#define pr_fmt(fmt) "TCP: " fmt
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/sysctl.h>
#include <linux/kernel.h>
#include <linux/prefetch.h>
#include <net/dst.h>
#include <net/tcp.h>
#include <net/inet_common.h>
#include <linux/ipsec.h>
#include <asm/unaligned.h>
#include <linux/errqueue.h>
#include <trace/events/tcp.h>
#include <linux/jump_label_ratelimit.h>
#include <net/busy_poll.h>
#include <net/mptcp.h>
int sysctl_tcp_max_orphans __read_mostly = NR_FILE;
#define FLAG_DATA 0x01 /* Incoming frame contained data. */
#define FLAG_WIN_UPDATE 0x02 /* Incoming ACK was a window update. */
#define FLAG_DATA_ACKED 0x04 /* This ACK acknowledged new data. */
#define FLAG_RETRANS_DATA_ACKED 0x08 /* "" "" some of which was retransmitted. */
#define FLAG_SYN_ACKED 0x10 /* This ACK acknowledged SYN. */
#define FLAG_DATA_SACKED 0x20 /* New SACK. */
#define FLAG_ECE 0x40 /* ECE in this ACK */
#define FLAG_LOST_RETRANS 0x80 /* This ACK marks some retransmission lost */
#define FLAG_SLOWPATH 0x100 /* Do not skip RFC checks for window update.*/
#define FLAG_ORIG_SACK_ACKED 0x200 /* Never retransmitted data are (s)acked */
#define FLAG_SND_UNA_ADVANCED 0x400 /* Snd_una was changed (!= FLAG_DATA_ACKED) */
#define FLAG_DSACKING_ACK 0x800 /* SACK blocks contained D-SACK info */
#define FLAG_SET_XMIT_TIMER 0x1000 /* Set TLP or RTO timer */
#define FLAG_SACK_RENEGING 0x2000 /* snd_una advanced to a sacked seq */
#define FLAG_UPDATE_TS_RECENT 0x4000 /* tcp_replace_ts_recent() */
#define FLAG_NO_CHALLENGE_ACK 0x8000 /* do not call tcp_send_challenge_ack() */
#define FLAG_ACK_MAYBE_DELAYED 0x10000 /* Likely a delayed ACK */
#define FLAG_DSACK_TLP 0x20000 /* DSACK for tail loss probe */
#define FLAG_ACKED (FLAG_DATA_ACKED|FLAG_SYN_ACKED)
#define FLAG_NOT_DUP (FLAG_DATA|FLAG_WIN_UPDATE|FLAG_ACKED)
#define FLAG_CA_ALERT (FLAG_DATA_SACKED|FLAG_ECE|FLAG_DSACKING_ACK)
#define FLAG_FORWARD_PROGRESS (FLAG_ACKED|FLAG_DATA_SACKED)
#define TCP_REMNANT (TCP_FLAG_FIN|TCP_FLAG_URG|TCP_FLAG_SYN|TCP_FLAG_PSH)
#define TCP_HP_BITS (~(TCP_RESERVED_BITS|TCP_FLAG_PSH))
#define REXMIT_NONE 0 /* no loss recovery to do */
#define REXMIT_LOST 1 /* retransmit packets marked lost */
#define REXMIT_NEW 2 /* FRTO-style transmit of unsent/new packets */
#if IS_ENABLED(CONFIG_TLS_DEVICE)
static DEFINE_STATIC_KEY_DEFERRED_FALSE(clean_acked_data_enabled, HZ);
void clean_acked_data_enable(struct inet_connection_sock *icsk,
void (*cad)(struct sock *sk, u32 ack_seq))
{
icsk->icsk_clean_acked = cad;
static_branch_deferred_inc(&clean_acked_data_enabled);
}
EXPORT_SYMBOL_GPL(clean_acked_data_enable);
void clean_acked_data_disable(struct inet_connection_sock *icsk)
{
static_branch_slow_dec_deferred(&clean_acked_data_enabled);
icsk->icsk_clean_acked = NULL;
}
EXPORT_SYMBOL_GPL(clean_acked_data_disable);
void clean_acked_data_flush(void)
{
static_key_deferred_flush(&clean_acked_data_enabled);
}
EXPORT_SYMBOL_GPL(clean_acked_data_flush);
#endif
#ifdef CONFIG_CGROUP_BPF
static void bpf_skops_parse_hdr(struct sock *sk, struct sk_buff *skb)
{
bool unknown_opt = tcp_sk(sk)->rx_opt.saw_unknown &&
BPF_SOCK_OPS_TEST_FLAG(tcp_sk(sk),
BPF_SOCK_OPS_PARSE_UNKNOWN_HDR_OPT_CB_FLAG);
bool parse_all_opt = BPF_SOCK_OPS_TEST_FLAG(tcp_sk(sk),
BPF_SOCK_OPS_PARSE_ALL_HDR_OPT_CB_FLAG);
struct bpf_sock_ops_kern sock_ops;
if (likely(!unknown_opt && !parse_all_opt))
return;
switch (sk->sk_state) {
case TCP_SYN_RECV:
case TCP_SYN_SENT:
case TCP_LISTEN:
return;
}
sock_owned_by_me(sk);
memset(&sock_ops, 0, offsetof(struct bpf_sock_ops_kern, temp));
sock_ops.op = BPF_SOCK_OPS_PARSE_HDR_OPT_CB;
sock_ops.is_fullsock = 1;
sock_ops.sk = sk;
bpf_skops_init_skb(&sock_ops, skb, tcp_hdrlen(skb));
BPF_CGROUP_RUN_PROG_SOCK_OPS(&sock_ops);
}
static void bpf_skops_established(struct sock *sk, int bpf_op,
struct sk_buff *skb)
{
struct bpf_sock_ops_kern sock_ops;
sock_owned_by_me(sk);
memset(&sock_ops, 0, offsetof(struct bpf_sock_ops_kern, temp));
sock_ops.op = bpf_op;
sock_ops.is_fullsock = 1;
sock_ops.sk = sk;
if (skb)
bpf_skops_init_skb(&sock_ops, skb, tcp_hdrlen(skb));
BPF_CGROUP_RUN_PROG_SOCK_OPS(&sock_ops);
}
#else
static void bpf_skops_parse_hdr(struct sock *sk, struct sk_buff *skb)
{
}
static void bpf_skops_established(struct sock *sk, int bpf_op,
struct sk_buff *skb)
{
}
#endif
static void tcp_gro_dev_warn(struct sock *sk, const struct sk_buff *skb,
unsigned int len)
{
static bool __once __read_mostly;
if (!__once) {
struct net_device *dev;
__once = true;
rcu_read_lock();
dev = dev_get_by_index_rcu(sock_net(sk), skb->skb_iif);
if (!dev || len >= dev->mtu)
pr_warn("%s: Driver has suspect GRO implementation, TCP performance may be compromised.\n",
dev ? dev->name : "Unknown driver");
rcu_read_unlock();
}
}
static void tcp_measure_rcv_mss(struct sock *sk, const struct sk_buff *skb)
{
struct inet_connection_sock *icsk = inet_csk(sk);
const unsigned int lss = icsk->icsk_ack.last_seg_size;
unsigned int len;
icsk->icsk_ack.last_seg_size = 0;
len = skb_shinfo(skb)->gso_size ? : skb->len;
if (len >= icsk->icsk_ack.rcv_mss) {
if (unlikely(len != icsk->icsk_ack.rcv_mss)) {
u64 val = (u64)skb->len << TCP_RMEM_TO_WIN_SCALE;
do_div(val, skb->truesize);
tcp_sk(sk)->scaling_ratio = val ? val : 1;
}
icsk->icsk_ack.rcv_mss = min_t(unsigned int, len,
tcp_sk(sk)->advmss);
if (unlikely(len > icsk->icsk_ack.rcv_mss +
MAX_TCP_OPTION_SPACE))
tcp_gro_dev_warn(sk, skb, len);
if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_PSH)
icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
} else {
len += skb->data - skb_transport_header(skb);
if (len >= TCP_MSS_DEFAULT + sizeof(struct tcphdr) ||
(len >= TCP_MIN_MSS + sizeof(struct tcphdr) &&
!(tcp_flag_word(tcp_hdr(skb)) & TCP_REMNANT))) {
len -= tcp_sk(sk)->tcp_header_len;
icsk->icsk_ack.last_seg_size = len;
if (len == lss) {
icsk->icsk_ack.rcv_mss = len;
return;
}
}
if (icsk->icsk_ack.pending & ICSK_ACK_PUSHED)
icsk->icsk_ack.pending |= ICSK_ACK_PUSHED2;
icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
}
}
static void tcp_incr_quickack(struct sock *sk, unsigned int max_quickacks)
{
struct inet_connection_sock *icsk = inet_csk(sk);
unsigned int quickacks = tcp_sk(sk)->rcv_wnd / (2 * icsk->icsk_ack.rcv_mss);
if (quickacks == 0)
quickacks = 2;
quickacks = min(quickacks, max_quickacks);
if (quickacks > icsk->icsk_ack.quick)
icsk->icsk_ack.quick = quickacks;
}
static void tcp_enter_quickack_mode(struct sock *sk, unsigned int max_quickacks)
{
struct inet_connection_sock *icsk = inet_csk(sk);
tcp_incr_quickack(sk, max_quickacks);
inet_csk_exit_pingpong_mode(sk);
icsk->icsk_ack.ato = TCP_ATO_MIN;
}
static bool tcp_in_quickack_mode(struct sock *sk)
{
const struct inet_connection_sock *icsk = inet_csk(sk);
const struct dst_entry *dst = __sk_dst_get(sk);
return (dst && dst_metric(dst, RTAX_QUICKACK)) ||
(icsk->icsk_ack.quick && !inet_csk_in_pingpong_mode(sk));
}
static void tcp_ecn_queue_cwr(struct tcp_sock *tp)
{
if (tp->ecn_flags & TCP_ECN_OK)
tp->ecn_flags |= TCP_ECN_QUEUE_CWR;
}
static void tcp_ecn_accept_cwr(struct sock *sk, const struct sk_buff *skb)
{
if (tcp_hdr(skb)->cwr) {
tcp_sk(sk)->ecn_flags &= ~TCP_ECN_DEMAND_CWR;
if (TCP_SKB_CB(skb)->seq != TCP_SKB_CB(skb)->end_seq)
inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_NOW;
}
}
static void tcp_ecn_withdraw_cwr(struct tcp_sock *tp)
{
tp->ecn_flags &= ~TCP_ECN_QUEUE_CWR;
}
static void __tcp_ecn_check_ce(struct sock *sk, const struct sk_buff *skb)
{
struct tcp_sock *tp = tcp_sk(sk);
switch (TCP_SKB_CB(skb)->ip_dsfield & INET_ECN_MASK) {
case INET_ECN_NOT_ECT:
if (tp->ecn_flags & TCP_ECN_SEEN)
tcp_enter_quickack_mode(sk, 2);
break;
case INET_ECN_CE:
if (tcp_ca_needs_ecn(sk))
tcp_ca_event(sk, CA_EVENT_ECN_IS_CE);
if (!(tp->ecn_flags & TCP_ECN_DEMAND_CWR)) {
tcp_enter_quickack_mode(sk, 2);
tp->ecn_flags |= TCP_ECN_DEMAND_CWR;
}
tp->ecn_flags |= TCP_ECN_SEEN;
break;
default:
if (tcp_ca_needs_ecn(sk))
tcp_ca_event(sk, CA_EVENT_ECN_NO_CE);
tp->ecn_flags |= TCP_ECN_SEEN;
break;
}
}
static void tcp_ecn_check_ce(struct sock *sk, const struct sk_buff *skb)
{
if (tcp_sk(sk)->ecn_flags & TCP_ECN_OK)
__tcp_ecn_check_ce(sk, skb);
}
static void tcp_ecn_rcv_synack(struct tcp_sock *tp, const struct tcphdr *th)
{
if ((tp->ecn_flags & TCP_ECN_OK) && (!th->ece || th->cwr))
tp->ecn_flags &= ~TCP_ECN_OK;
}
static void tcp_ecn_rcv_syn(struct tcp_sock *tp, const struct tcphdr *th)
{
if ((tp->ecn_flags & TCP_ECN_OK) && (!th->ece || !th->cwr))
tp->ecn_flags &= ~TCP_ECN_OK;
}
static bool tcp_ecn_rcv_ecn_echo(const struct tcp_sock *tp, const struct tcphdr *th)
{
if (th->ece && !th->syn && (tp->ecn_flags & TCP_ECN_OK))
return true;
return false;
}
static void tcp_sndbuf_expand(struct sock *sk)
{
const struct tcp_sock *tp = tcp_sk(sk);
const struct tcp_congestion_ops *ca_ops = inet_csk(sk)->icsk_ca_ops;
int sndmem, per_mss;
u32 nr_segs;
per_mss = max_t(u32, tp->rx_opt.mss_clamp, tp->mss_cache) +
MAX_TCP_HEADER +
SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
per_mss = roundup_pow_of_two(per_mss) +
SKB_DATA_ALIGN(sizeof(struct sk_buff));
nr_segs = max_t(u32, TCP_INIT_CWND, tcp_snd_cwnd(tp));
nr_segs = max_t(u32, nr_segs, tp->reordering + 1);
sndmem = ca_ops->sndbuf_expand ? ca_ops->sndbuf_expand(sk) : 2;
sndmem *= nr_segs * per_mss;
if (sk->sk_sndbuf < sndmem)
WRITE_ONCE(sk->sk_sndbuf,
min(sndmem, READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_wmem[2])));
}
static int __tcp_grow_window(const struct sock *sk, const struct sk_buff *skb,
unsigned int skbtruesize)
{
const struct tcp_sock *tp = tcp_sk(sk);
int truesize = tcp_win_from_space(sk, skbtruesize) >> 1;
int window = tcp_win_from_space(sk, READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_rmem[2])) >> 1;
while (tp->rcv_ssthresh <= window) {
if (truesize <= skb->len)
return 2 * inet_csk(sk)->icsk_ack.rcv_mss;
truesize >>= 1;
window >>= 1;
}
return 0;
}
static u32 truesize_adjust(bool adjust, const struct sk_buff *skb)
{
u32 truesize = skb->truesize;
if (adjust && !skb_headlen(skb)) {
truesize -= SKB_TRUESIZE(skb_end_offset(skb));
if (unlikely((int)truesize < (int)skb->len))
truesize = skb->truesize;
}
return truesize;
}
static void tcp_grow_window(struct sock *sk, const struct sk_buff *skb,
bool adjust)
{
struct tcp_sock *tp = tcp_sk(sk);
int room;
room = min_t(int, tp->window_clamp, tcp_space(sk)) - tp->rcv_ssthresh;
if (room <= 0)
return;
if (!tcp_under_memory_pressure(sk)) {
unsigned int truesize = truesize_adjust(adjust, skb);
int incr;
if (tcp_win_from_space(sk, truesize) <= skb->len)
incr = 2 * tp->advmss;
else
incr = __tcp_grow_window(sk, skb, truesize);
if (incr) {
incr = max_t(int, incr, 2 * skb->len);
tp->rcv_ssthresh += min(room, incr);
inet_csk(sk)->icsk_ack.quick |= 1;
}
} else {
tcp_adjust_rcv_ssthresh(sk);
}
}
static void tcp_init_buffer_space(struct sock *sk)
{
int tcp_app_win = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_app_win);
struct tcp_sock *tp = tcp_sk(sk);
int maxwin;
if (!(sk->sk_userlocks & SOCK_SNDBUF_LOCK))
tcp_sndbuf_expand(sk);
tcp_mstamp_refresh(tp);
tp->rcvq_space.time = tp->tcp_mstamp;
tp->rcvq_space.seq = tp->copied_seq;
maxwin = tcp_full_space(sk);
if (tp->window_clamp >= maxwin) {
tp->window_clamp = maxwin;
if (tcp_app_win && maxwin > 4 * tp->advmss)
tp->window_clamp = max(maxwin -
(maxwin >> tcp_app_win),
4 * tp->advmss);
}
if (tcp_app_win &&
tp->window_clamp > 2 * tp->advmss &&
tp->window_clamp + tp->advmss > maxwin)
tp->window_clamp = max(2 * tp->advmss, maxwin - tp->advmss);
tp->rcv_ssthresh = min(tp->rcv_ssthresh, tp->window_clamp);
tp->snd_cwnd_stamp = tcp_jiffies32;
tp->rcvq_space.space = min3(tp->rcv_ssthresh, tp->rcv_wnd,
(u32)TCP_INIT_CWND * tp->advmss);
}
static void tcp_clamp_window(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);
struct inet_connection_sock *icsk = inet_csk(sk);
struct net *net = sock_net(sk);
int rmem2;
icsk->icsk_ack.quick = 0;
rmem2 = READ_ONCE(net->ipv4.sysctl_tcp_rmem[2]);
if (sk->sk_rcvbuf < rmem2 &&
!(sk->sk_userlocks & SOCK_RCVBUF_LOCK) &&
!tcp_under_memory_pressure(sk) &&
sk_memory_allocated(sk) < sk_prot_mem_limits(sk, 0)) {
WRITE_ONCE(sk->sk_rcvbuf,
min(atomic_read(&sk->sk_rmem_alloc), rmem2));
}
if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf)
tp->rcv_ssthresh = min(tp->window_clamp, 2U * tp->advmss);
}
void tcp_initialize_rcv_mss(struct sock *sk)
{
const struct tcp_sock *tp = tcp_sk(sk);
unsigned int hint = min_t(unsigned int, tp->advmss, tp->mss_cache);
hint = min(hint, tp->rcv_wnd / 2);
hint = min(hint, TCP_MSS_DEFAULT);
hint = max(hint, TCP_MIN_MSS);
inet_csk(sk)->icsk_ack.rcv_mss = hint;
}
EXPORT_SYMBOL(tcp_initialize_rcv_mss);
static void tcp_rcv_rtt_update(struct tcp_sock *tp, u32 sample, int win_dep)
{
u32 new_sample = tp->rcv_rtt_est.rtt_us;
long m = sample;
if (new_sample != 0) {
if (!win_dep) {
m -= (new_sample >> 3);
new_sample += m;
} else {
m <<= 3;
if (m < new_sample)
new_sample = m;
}
} else {
new_sample = m << 3;
}
tp->rcv_rtt_est.rtt_us = new_sample;
}
static inline void tcp_rcv_rtt_measure(struct tcp_sock *tp)
{
u32 delta_us;
if (tp->rcv_rtt_est.time == 0)
goto new_measure;
if (before(tp->rcv_nxt, tp->rcv_rtt_est.seq))
return;
delta_us = tcp_stamp_us_delta(tp->tcp_mstamp, tp->rcv_rtt_est.time);
if (!delta_us)
delta_us = 1;
tcp_rcv_rtt_update(tp, delta_us, 1);
new_measure:
tp->rcv_rtt_est.seq = tp->rcv_nxt + tp->rcv_wnd;
tp->rcv_rtt_est.time = tp->tcp_mstamp;
}
static inline void tcp_rcv_rtt_measure_ts(struct sock *sk,
const struct sk_buff *skb)
{
struct tcp_sock *tp = tcp_sk(sk);
if (tp->rx_opt.rcv_tsecr == tp->rcv_rtt_last_tsecr)
return;
tp->rcv_rtt_last_tsecr = tp->rx_opt.rcv_tsecr;
if (TCP_SKB_CB(skb)->end_seq -
TCP_SKB_CB(skb)->seq >= inet_csk(sk)->icsk_ack.rcv_mss) {
u32 delta = tcp_time_stamp(tp) - tp->rx_opt.rcv_tsecr;
u32 delta_us;
if (likely(delta < INT_MAX / (USEC_PER_SEC / TCP_TS_HZ))) {
if (!delta)
delta = 1;
delta_us = delta * (USEC_PER_SEC / TCP_TS_HZ);
tcp_rcv_rtt_update(tp, delta_us, 0);
}
}
}
void tcp_rcv_space_adjust(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);
u32 copied;
int time;
trace_tcp_rcv_space_adjust(sk);
tcp_mstamp_refresh(tp);
time = tcp_stamp_us_delta(tp->tcp_mstamp, tp->rcvq_space.time);
if (time < (tp->rcv_rtt_est.rtt_us >> 3) || tp->rcv_rtt_est.rtt_us == 0)
return;
copied = tp->copied_seq - tp->rcvq_space.seq;
if (copied <= tp->rcvq_space.space)
goto new_measure;
if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf) &&
!(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {
u64 rcvwin, grow;
int rcvbuf;
rcvwin = ((u64)copied << 1) + 16 * tp->advmss;
grow = rcvwin * (copied - tp->rcvq_space.space);
do_div(grow, tp->rcvq_space.space);
rcvwin += (grow << 1);
rcvbuf = min_t(u64, tcp_space_from_win(sk, rcvwin),
READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_rmem[2]));
if (rcvbuf > sk->sk_rcvbuf) {
WRITE_ONCE(sk->sk_rcvbuf, rcvbuf);
tp->window_clamp = tcp_win_from_space(sk, rcvbuf);
}
}
tp->rcvq_space.space = copied;
new_measure:
tp->rcvq_space.seq = tp->copied_seq;
tp->rcvq_space.time = tp->tcp_mstamp;
}
static void tcp_event_data_recv(struct sock *sk, struct sk_buff *skb)
{
struct tcp_sock *tp = tcp_sk(sk);
struct inet_connection_sock *icsk = inet_csk(sk);
u32 now;
inet_csk_schedule_ack(sk);
tcp_measure_rcv_mss(sk, skb);
tcp_rcv_rtt_measure(tp);
now = tcp_jiffies32;
if (!icsk->icsk_ack.ato) {
tcp_incr_quickack(sk, TCP_MAX_QUICKACKS);
icsk->icsk_ack.ato = TCP_ATO_MIN;
} else {
int m = now - icsk->icsk_ack.lrcvtime;
if (m <= TCP_ATO_MIN / 2) {
icsk->icsk_ack.ato = (icsk->icsk_ack.ato >> 1) + TCP_ATO_MIN / 2;
} else if (m < icsk->icsk_ack.ato) {
icsk->icsk_ack.ato = (icsk->icsk_ack.ato >> 1) + m;
if (icsk->icsk_ack.ato > icsk->icsk_rto)
icsk->icsk_ack.ato = icsk->icsk_rto;
} else if (m > icsk->icsk_rto) {
tcp_incr_quickack(sk, TCP_MAX_QUICKACKS);
}
}
icsk->icsk_ack.lrcvtime = now;
tcp_ecn_check_ce(sk, skb);
if (skb->len >= 128)
tcp_grow_window(sk, skb, true);
}
static void tcp_rtt_estimator(struct sock *sk, long mrtt_us)
{
struct tcp_sock *tp = tcp_sk(sk);
long m = mrtt_us;
u32 srtt = tp->srtt_us;
if (srtt != 0) {
m -= (srtt >> 3);
srtt += m;
if (m < 0) {
m = -m;
m -= (tp->mdev_us >> 2);
if (m > 0)
m >>= 3;
} else {
m -= (tp->mdev_us >> 2);
}
tp->mdev_us += m;
if (tp->mdev_us > tp->mdev_max_us) {
tp->mdev_max_us = tp->mdev_us;
if (tp->mdev_max_us > tp->rttvar_us)
tp->rttvar_us = tp->mdev_max_us;
}
if (after(tp->snd_una, tp->rtt_seq)) {
if (tp->mdev_max_us < tp->rttvar_us)
tp->rttvar_us -= (tp->rttvar_us - tp->mdev_max_us) >> 2;
tp->rtt_seq = tp->snd_nxt;
tp->mdev_max_us = tcp_rto_min_us(sk);
tcp_bpf_rtt(sk);
}
} else {
srtt = m << 3;
tp->mdev_us = m << 1;
tp->rttvar_us = max(tp->mdev_us, tcp_rto_min_us(sk));
tp->mdev_max_us = tp->rttvar_us;
tp->rtt_seq = tp->snd_nxt;
tcp_bpf_rtt(sk);
}
tp->srtt_us = max(1U, srtt);
}
static void tcp_update_pacing_rate(struct sock *sk)
{
const struct tcp_sock *tp = tcp_sk(sk);
u64 rate;
rate = (u64)tp->mss_cache * ((USEC_PER_SEC / 100) << 3);
if (tcp_snd_cwnd(tp) < tp->snd_ssthresh / 2)
rate *= READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_pacing_ss_ratio);
else
rate *= READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_pacing_ca_ratio);
rate *= max(tcp_snd_cwnd(tp), tp->packets_out);
if (likely(tp->srtt_us))
do_div(rate, tp->srtt_us);
WRITE_ONCE(sk->sk_pacing_rate, min_t(u64, rate,
sk->sk_max_pacing_rate));
}
static void tcp_set_rto(struct sock *sk)
{
const struct tcp_sock *tp = tcp_sk(sk);
inet_csk(sk)->icsk_rto = __tcp_set_rto(tp);
tcp_bound_rto(sk);
}
__u32 tcp_init_cwnd(const struct tcp_sock *tp, const struct dst_entry *dst)
{
__u32 cwnd = (dst ? dst_metric(dst, RTAX_INITCWND) : 0);
if (!cwnd)
cwnd = TCP_INIT_CWND;
return min_t(__u32, cwnd, tp->snd_cwnd_clamp);
}
struct tcp_sacktag_state {
u64 first_sackt;
u64 last_sackt;
u32 reord;
u32 sack_delivered;
int flag;
unsigned int mss_now;
struct rate_sample *rate;
};
static u32 tcp_dsack_seen(struct tcp_sock *tp, u32 start_seq,
u32 end_seq, struct tcp_sacktag_state *state)
{
u32 seq_len, dup_segs = 1;
if (!before(start_seq, end_seq))
return 0;
seq_len = end_seq - start_seq;
if (seq_len > tp->max_window)
return 0;
if (seq_len > tp->mss_cache)
dup_segs = DIV_ROUND_UP(seq_len, tp->mss_cache);
else if (tp->tlp_high_seq && tp->tlp_high_seq == end_seq)
state->flag |= FLAG_DSACK_TLP;
tp->dsack_dups += dup_segs;
if (tp->dsack_dups > tp->total_retrans)
return 0;
tp->rx_opt.sack_ok |= TCP_DSACK_SEEN;
if (tp->reord_seen && !(state->flag & FLAG_DSACK_TLP))
tp->rack.dsack_seen = 1;
state->flag |= FLAG_DSACKING_ACK;
state->sack_delivered += dup_segs;
return dup_segs;
}
static void tcp_check_sack_reordering(struct sock *sk, const u32 low_seq,
const int ts)
{
struct tcp_sock *tp = tcp_sk(sk);
const u32 mss = tp->mss_cache;
u32 fack, metric;
fack = tcp_highest_sack_seq(tp);
if (!before(low_seq, fack))
return;
metric = fack - low_seq;
if ((metric > tp->reordering * mss) && mss) {
#if FASTRETRANS_DEBUG > 1
pr_debug("Disorder%d %d %u f%u s%u rr%d\n",
tp->rx_opt.sack_ok, inet_csk(sk)->icsk_ca_state,
tp->reordering,
0,
tp->sacked_out,
tp->undo_marker ? tp->undo_retrans : 0);
#endif
tp->reordering = min_t(u32, (metric + mss - 1) / mss,
READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_max_reordering));
}
tp->reord_seen++;
NET_INC_STATS(sock_net(sk),
ts ? LINUX_MIB_TCPTSREORDER : LINUX_MIB_TCPSACKREORDER);
}
static void tcp_verify_retransmit_hint(struct tcp_sock *tp, struct sk_buff *skb)
{
if ((!tp->retransmit_skb_hint && tp->retrans_out >= tp->lost_out) ||
(tp->retransmit_skb_hint &&
before(TCP_SKB_CB(skb)->seq,
TCP_SKB_CB(tp->retransmit_skb_hint)->seq)))
tp->retransmit_skb_hint = skb;
}
static void tcp_notify_skb_loss_event(struct tcp_sock *tp, const struct sk_buff *skb)
{
tp->lost += tcp_skb_pcount(skb);
}
void tcp_mark_skb_lost(struct sock *sk, struct sk_buff *skb)
{
__u8 sacked = TCP_SKB_CB(skb)->sacked;
struct tcp_sock *tp = tcp_sk(sk);
if (sacked & TCPCB_SACKED_ACKED)
return;
tcp_verify_retransmit_hint(tp, skb);
if (sacked & TCPCB_LOST) {
if (sacked & TCPCB_SACKED_RETRANS) {
TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_RETRANS;
tp->retrans_out -= tcp_skb_pcount(skb);
NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPLOSTRETRANSMIT,
tcp_skb_pcount(skb));
tcp_notify_skb_loss_event(tp, skb);
}
} else {
tp->lost_out += tcp_skb_pcount(skb);
TCP_SKB_CB(skb)->sacked |= TCPCB_LOST;
tcp_notify_skb_loss_event(tp, skb);
}
}
static void tcp_count_delivered(struct tcp_sock *tp, u32 delivered,
bool ece_ack)
{
tp->delivered += delivered;
if (ece_ack)
tp->delivered_ce += delivered;
}
static bool tcp_is_sackblock_valid(struct tcp_sock *tp, bool is_dsack,
u32 start_seq, u32 end_seq)
{
if (after(end_seq, tp->snd_nxt) || !before(start_seq, end_seq))
return false;
if (!before(start_seq, tp->snd_nxt))
return false;
if (after(start_seq, tp->snd_una))
return true;
if (!is_dsack || !tp->undo_marker)
return false;
if (after(end_seq, tp->snd_una))
return false;
if (!before(start_seq, tp->undo_marker))
return true;
if (!after(end_seq, tp->undo_marker))
return false;
return !before(start_seq, end_seq - tp->max_window);
}
static bool tcp_check_dsack(struct sock *sk, const struct sk_buff *ack_skb,
struct tcp_sack_block_wire *sp, int num_sacks,
u32 prior_snd_una, struct tcp_sacktag_state *state)
{
struct tcp_sock *tp = tcp_sk(sk);
u32 start_seq_0 = get_unaligned_be32(&sp[0].start_seq);
u32 end_seq_0 = get_unaligned_be32(&sp[0].end_seq);
u32 dup_segs;
if (before(start_seq_0, TCP_SKB_CB(ack_skb)->ack_seq)) {
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPDSACKRECV);
} else if (num_sacks > 1) {
u32 end_seq_1 = get_unaligned_be32(&sp[1].end_seq);
u32 start_seq_1 = get_unaligned_be32(&sp[1].start_seq);
if (after(end_seq_0, end_seq_1) || before(start_seq_0, start_seq_1))
return false;
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPDSACKOFORECV);
} else {
return false;
}
dup_segs = tcp_dsack_seen(tp, start_seq_0, end_seq_0, state);
if (!dup_segs) {
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPDSACKIGNOREDDUBIOUS);
return false;
}
NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPDSACKRECVSEGS, dup_segs);
if (tp->undo_marker && tp->undo_retrans > 0 &&
!after(end_seq_0, prior_snd_una) &&
after(end_seq_0, tp->undo_marker))
tp->undo_retrans = max_t(int, 0, tp->undo_retrans - dup_segs);
return true;
}
static int tcp_match_skb_to_sack(struct sock *sk, struct sk_buff *skb,
u32 start_seq, u32 end_seq)
{
int err;
bool in_sack;
unsigned int pkt_len;
unsigned int mss;
in_sack = !after(start_seq, TCP_SKB_CB(skb)->seq) &&
!before(end_seq, TCP_SKB_CB(skb)->end_seq);
if (tcp_skb_pcount(skb) > 1 && !in_sack &&
after(TCP_SKB_CB(skb)->end_seq, start_seq)) {
mss = tcp_skb_mss(skb);
in_sack = !after(start_seq, TCP_SKB_CB(skb)->seq);
if (!in_sack) {
pkt_len = start_seq - TCP_SKB_CB(skb)->seq;
if (pkt_len < mss)
pkt_len = mss;
} else {
pkt_len = end_seq - TCP_SKB_CB(skb)->seq;
if (pkt_len < mss)
return -EINVAL;
}
if (pkt_len > mss) {
unsigned int new_len = (pkt_len / mss) * mss;
if (!in_sack && new_len < pkt_len)
new_len += mss;
pkt_len = new_len;
}
if (pkt_len >= skb->len && !in_sack)
return 0;
err = tcp_fragment(sk, TCP_FRAG_IN_RTX_QUEUE, skb,
pkt_len, mss, GFP_ATOMIC);
if (err < 0)
return err;
}
return in_sack;
}
static u8 tcp_sacktag_one(struct sock *sk,
struct tcp_sacktag_state *state, u8 sacked,
u32 start_seq, u32 end_seq,
int dup_sack, int pcount,
u64 xmit_time)
{
struct tcp_sock *tp = tcp_sk(sk);
if (dup_sack && (sacked & TCPCB_RETRANS)) {
if (tp->undo_marker && tp->undo_retrans > 0 &&
after(end_seq, tp->undo_marker))
tp->undo_retrans = max_t(int, 0, tp->undo_retrans - pcount);
if ((sacked & TCPCB_SACKED_ACKED) &&
before(start_seq, state->reord))
state->reord = start_seq;
}
if (!after(end_seq, tp->snd_una))
return sacked;
if (!(sacked & TCPCB_SACKED_ACKED)) {
tcp_rack_advance(tp, sacked, end_seq, xmit_time);
if (sacked & TCPCB_SACKED_RETRANS) {
if (sacked & TCPCB_LOST) {
sacked &= ~(TCPCB_LOST|TCPCB_SACKED_RETRANS);
tp->lost_out -= pcount;
tp->retrans_out -= pcount;
}
} else {
if (!(sacked & TCPCB_RETRANS)) {
if (before(start_seq,
tcp_highest_sack_seq(tp)) &&
before(start_seq, state->reord))
state->reord = start_seq;
if (!after(end_seq, tp->high_seq))
state->flag |= FLAG_ORIG_SACK_ACKED;
if (state->first_sackt == 0)
state->first_sackt = xmit_time;
state->last_sackt = xmit_time;
}
if (sacked & TCPCB_LOST) {
sacked &= ~TCPCB_LOST;
tp->lost_out -= pcount;
}
}
sacked |= TCPCB_SACKED_ACKED;
state->flag |= FLAG_DATA_SACKED;
tp->sacked_out += pcount;
state->sack_delivered += pcount;
if (tp->lost_skb_hint &&
before(start_seq, TCP_SKB_CB(tp->lost_skb_hint)->seq))
tp->lost_cnt_hint += pcount;
}
if (dup_sack && (sacked & TCPCB_SACKED_RETRANS)) {
sacked &= ~TCPCB_SACKED_RETRANS;
tp->retrans_out -= pcount;
}
return sacked;
}
static bool tcp_shifted_skb(struct sock *sk, struct sk_buff *prev,
struct sk_buff *skb,
struct tcp_sacktag_state *state,
unsigned int pcount, int shifted, int mss,
bool dup_sack)
{
struct tcp_sock *tp = tcp_sk(sk);
u32 start_seq = TCP_SKB_CB(skb)->seq;
u32 end_seq = start_seq + shifted;
BUG_ON(!pcount);
tcp_sacktag_one(sk, state, TCP_SKB_CB(skb)->sacked,
start_seq, end_seq, dup_sack, pcount,
tcp_skb_timestamp_us(skb));
tcp_rate_skb_delivered(sk, skb, state->rate);
if (skb == tp->lost_skb_hint)
tp->lost_cnt_hint += pcount;
TCP_SKB_CB(prev)->end_seq += shifted;
TCP_SKB_CB(skb)->seq += shifted;
tcp_skb_pcount_add(prev, pcount);
WARN_ON_ONCE(tcp_skb_pcount(skb) < pcount);
tcp_skb_pcount_add(skb, -pcount);
if (!TCP_SKB_CB(prev)->tcp_gso_size)
TCP_SKB_CB(prev)->tcp_gso_size = mss;
if (tcp_skb_pcount(skb) <= 1)
TCP_SKB_CB(skb)->tcp_gso_size = 0;
TCP_SKB_CB(prev)->sacked |= (TCP_SKB_CB(skb)->sacked & TCPCB_EVER_RETRANS);
if (skb->len > 0) {
BUG_ON(!tcp_skb_pcount(skb));
NET_INC_STATS(sock_net(sk), LINUX_MIB_SACKSHIFTED);
return false;
}
if (skb == tp->retransmit_skb_hint)
tp->retransmit_skb_hint = prev;
if (skb == tp->lost_skb_hint) {
tp->lost_skb_hint = prev;
tp->lost_cnt_hint -= tcp_skb_pcount(prev);
}
TCP_SKB_CB(prev)->tcp_flags |= TCP_SKB_CB(skb)->tcp_flags;
TCP_SKB_CB(prev)->eor = TCP_SKB_CB(skb)->eor;
if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
TCP_SKB_CB(prev)->end_seq++;
if (skb == tcp_highest_sack(sk))
tcp_advance_highest_sack(sk, skb);
tcp_skb_collapse_tstamp(prev, skb);
if (unlikely(TCP_SKB_CB(prev)->tx.delivered_mstamp))
TCP_SKB_CB(prev)->tx.delivered_mstamp = 0;
tcp_rtx_queue_unlink_and_free(skb, sk);
NET_INC_STATS(sock_net(sk), LINUX_MIB_SACKMERGED);
return true;
}
static int tcp_skb_seglen(const struct sk_buff *skb)
{
return tcp_skb_pcount(skb) == 1 ? skb->len : tcp_skb_mss(skb);
}
static int skb_can_shift(const struct sk_buff *skb)
{
return !skb_headlen(skb) && skb_is_nonlinear(skb);
}
int tcp_skb_shift(struct sk_buff *to, struct sk_buff *from,
int pcount, int shiftlen)
{
if (unlikely(to->len + shiftlen >= 65535 * TCP_MIN_GSO_SIZE))
return 0;
if (unlikely(tcp_skb_pcount(to) + pcount > 65535))
return 0;
return skb_shift(to, from, shiftlen);
}
static struct sk_buff *tcp_shift_skb_data(struct sock *sk, struct sk_buff *skb,
struct tcp_sacktag_state *state,
u32 start_seq, u32 end_seq,
bool dup_sack)
{
struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *prev;
int mss;
int pcount = 0;
int len;
int in_sack;
if (!dup_sack &&
(TCP_SKB_CB(skb)->sacked & (TCPCB_LOST|TCPCB_SACKED_RETRANS)) == TCPCB_SACKED_RETRANS)
goto fallback;
if (!skb_can_shift(skb))
goto fallback;
if (!after(TCP_SKB_CB(skb)->end_seq, tp->snd_una))
goto fallback;
prev = skb_rb_prev(skb);
if (!prev)
goto fallback;
if ((TCP_SKB_CB(prev)->sacked & TCPCB_TAGBITS) != TCPCB_SACKED_ACKED)
goto fallback;
if (!tcp_skb_can_collapse(prev, skb))
goto fallback;
in_sack = !after(start_seq, TCP_SKB_CB(skb)->seq) &&
!before(end_seq, TCP_SKB_CB(skb)->end_seq);
if (in_sack) {
len = skb->len;
pcount = tcp_skb_pcount(skb);
mss = tcp_skb_seglen(skb);
if (mss != tcp_skb_seglen(prev))
goto fallback;
} else {
if (!after(TCP_SKB_CB(skb)->end_seq, start_seq))
goto noop;
if (tcp_skb_pcount(skb) <= 1)
goto noop;
in_sack = !after(start_seq, TCP_SKB_CB(skb)->seq);
if (!in_sack) {
goto fallback;
}
len = end_seq - TCP_SKB_CB(skb)->seq;
BUG_ON(len < 0);
BUG_ON(len > skb->len);
mss = tcp_skb_mss(skb);
if (mss != tcp_skb_seglen(prev))
goto fallback;
if (len == mss) {
pcount = 1;
} else if (len < mss) {
goto noop;
} else {
pcount = len / mss;
len = pcount * mss;
}
}
if (!after(TCP_SKB_CB(skb)->seq + len, tp->snd_una))
goto fallback;
if (!tcp_skb_shift(prev, skb, pcount, len))
goto fallback;
if (!tcp_shifted_skb(sk, prev, skb, state, pcount, len, mss, dup_sack))
goto out;
skb = skb_rb_next(prev);
if (!skb)
goto out;
if (!skb_can_shift(skb) ||
((TCP_SKB_CB(skb)->sacked & TCPCB_TAGBITS) != TCPCB_SACKED_ACKED) ||
(mss != tcp_skb_seglen(skb)))
goto out;
if (!tcp_skb_can_collapse(prev, skb))
goto out;
len = skb->len;
pcount = tcp_skb_pcount(skb);
if (tcp_skb_shift(prev, skb, pcount, len))
tcp_shifted_skb(sk, prev, skb, state, pcount,
len, mss, 0);
out:
return prev;
noop:
return skb;
fallback:
NET_INC_STATS(sock_net(sk), LINUX_MIB_SACKSHIFTFALLBACK);
return NULL;
}
static struct sk_buff *tcp_sacktag_walk(struct sk_buff *skb, struct sock *sk,
struct tcp_sack_block *next_dup,
struct tcp_sacktag_state *state,
u32 start_seq, u32 end_seq,
bool dup_sack_in)
{
struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *tmp;
skb_rbtree_walk_from(skb) {
int in_sack = 0;
bool dup_sack = dup_sack_in;
if (!before(TCP_SKB_CB(skb)->seq, end_seq))
break;
if (next_dup &&
before(TCP_SKB_CB(skb)->seq, next_dup->end_seq)) {
in_sack = tcp_match_skb_to_sack(sk, skb,
next_dup->start_seq,
next_dup->end_seq);
if (in_sack > 0)
dup_sack = true;
}
if (in_sack <= 0) {
tmp = tcp_shift_skb_data(sk, skb, state,
start_seq, end_seq, dup_sack);
if (tmp) {
if (tmp != skb) {
skb = tmp;
continue;
}
in_sack = 0;
} else {
in_sack = tcp_match_skb_to_sack(sk, skb,
start_seq,
end_seq);
}
}
if (unlikely(in_sack < 0))
break;
if (in_sack) {
TCP_SKB_CB(skb)->sacked =
tcp_sacktag_one(sk,
state,
TCP_SKB_CB(skb)->sacked,
TCP_SKB_CB(skb)->seq,
TCP_SKB_CB(skb)->end_seq,
dup_sack,
tcp_skb_pcount(skb),
tcp_skb_timestamp_us(skb));
tcp_rate_skb_delivered(sk, skb, state->rate);
if (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)
list_del_init(&skb->tcp_tsorted_anchor);
if (!before(TCP_SKB_CB(skb)->seq,
tcp_highest_sack_seq(tp)))
tcp_advance_highest_sack(sk, skb);
}
}
return skb;
}
static struct sk_buff *tcp_sacktag_bsearch(struct sock *sk, u32 seq)
{
struct rb_node *parent, **p = &sk->tcp_rtx_queue.rb_node;
struct sk_buff *skb;
while (*p) {
parent = *p;
skb = rb_to_skb(parent);
if (before(seq, TCP_SKB_CB(skb)->seq)) {
p = &parent->rb_left;
continue;
}
if (!before(seq, TCP_SKB_CB(skb)->end_seq)) {
p = &parent->rb_right;
continue;
}
return skb;
}
return NULL;
}
static struct sk_buff *tcp_sacktag_skip(struct sk_buff *skb, struct sock *sk,
u32 skip_to_seq)
{
if (skb && after(TCP_SKB_CB(skb)->seq, skip_to_seq))
return skb;
return tcp_sacktag_bsearch(sk, skip_to_seq);
}
static struct sk_buff *tcp_maybe_skipping_dsack(struct sk_buff *skb,
struct sock *sk,
struct tcp_sack_block *next_dup,
struct tcp_sacktag_state *state,
u32 skip_to_seq)
{
if (!next_dup)
return skb;
if (before(next_dup->start_seq, skip_to_seq)) {
skb = tcp_sacktag_skip(skb, sk, next_dup->start_seq);
skb = tcp_sacktag_walk(skb, sk, NULL, state,
next_dup->start_seq, next_dup->end_seq,
1);
}
return skb;
}
static int tcp_sack_cache_ok(const struct tcp_sock *tp, const struct tcp_sack_block *cache)
{
return cache < tp->recv_sack_cache + ARRAY_SIZE(tp->recv_sack_cache);
}
static int
tcp_sacktag_write_queue(struct sock *sk, const struct sk_buff *ack_skb,
u32 prior_snd_una, struct tcp_sacktag_state *state)
{
struct tcp_sock *tp = tcp_sk(sk);
const unsigned char *ptr = (skb_transport_header(ack_skb) +
TCP_SKB_CB(ack_skb)->sacked);
struct tcp_sack_block_wire *sp_wire = (struct tcp_sack_block_wire *)(ptr+2);
struct tcp_sack_block sp[TCP_NUM_SACKS];
struct tcp_sack_block *cache;
struct sk_buff *skb;
int num_sacks = min(TCP_NUM_SACKS, (ptr[1] - TCPOLEN_SACK_BASE) >> 3);
int used_sacks;
bool found_dup_sack = false;
int i, j;
int first_sack_index;
state->flag = 0;
state->reord = tp->snd_nxt;
if (!tp->sacked_out)
tcp_highest_sack_reset(sk);
found_dup_sack = tcp_check_dsack(sk, ack_skb, sp_wire,
num_sacks, prior_snd_una, state);
if (before(TCP_SKB_CB(ack_skb)->ack_seq, prior_snd_una - tp->max_window))
return 0;
if (!tp->packets_out)
goto out;
used_sacks = 0;
first_sack_index = 0;
for (i = 0; i < num_sacks; i++) {
bool dup_sack = !i && found_dup_sack;
sp[used_sacks].start_seq = get_unaligned_be32(&sp_wire[i].start_seq);
sp[used_sacks].end_seq = get_unaligned_be32(&sp_wire[i].end_seq);
if (!tcp_is_sackblock_valid(tp, dup_sack,
sp[used_sacks].start_seq,
sp[used_sacks].end_seq)) {
int mib_idx;
if (dup_sack) {
if (!tp->undo_marker)
mib_idx = LINUX_MIB_TCPDSACKIGNOREDNOUNDO;
else
mib_idx = LINUX_MIB_TCPDSACKIGNOREDOLD;
} else {
if ((TCP_SKB_CB(ack_skb)->ack_seq != tp->snd_una) &&
!after(sp[used_sacks].end_seq, tp->snd_una))
continue;
mib_idx = LINUX_MIB_TCPSACKDISCARD;
}
NET_INC_STATS(sock_net(sk), mib_idx);
if (i == 0)
first_sack_index = -1;
continue;
}
if (!after(sp[used_sacks].end_seq, prior_snd_una)) {
if (i == 0)
first_sack_index = -1;
continue;
}
used_sacks++;
}
for (i = used_sacks - 1; i > 0; i--) {
for (j = 0; j < i; j++) {
if (after(sp[j].start_seq, sp[j + 1].start_seq)) {
swap(sp[j], sp[j + 1]);
if (j == first_sack_index)
first_sack_index = j + 1;
}
}
}
state->mss_now = tcp_current_mss(sk);
skb = NULL;
i = 0;
if (!tp->sacked_out) {
cache = tp->recv_sack_cache + ARRAY_SIZE(tp->recv_sack_cache);
} else {
cache = tp->recv_sack_cache;
while (tcp_sack_cache_ok(tp, cache) && !cache->start_seq &&
!cache->end_seq)
cache++;
}
while (i < used_sacks) {
u32 start_seq = sp[i].start_seq;
u32 end_seq = sp[i].end_seq;
bool dup_sack = (found_dup_sack && (i == first_sack_index));
struct tcp_sack_block *next_dup = NULL;
if (found_dup_sack && ((i + 1) == first_sack_index))
next_dup = &sp[i + 1];
while (tcp_sack_cache_ok(tp, cache) &&
!before(start_seq, cache->end_seq))
cache++;
if (tcp_sack_cache_ok(tp, cache) && !dup_sack &&
after(end_seq, cache->start_seq)) {
if (before(start_seq, cache->start_seq)) {
skb = tcp_sacktag_skip(skb, sk, start_seq);
skb = tcp_sacktag_walk(skb, sk, next_dup,
state,
start_seq,
cache->start_seq,
dup_sack);
}
if (!after(end_seq, cache->end_seq))
goto advance_sp;
skb = tcp_maybe_skipping_dsack(skb, sk, next_dup,
state,
cache->end_seq);
if (tcp_highest_sack_seq(tp) == cache->end_seq) {
skb = tcp_highest_sack(sk);
if (!skb)
break;
cache++;
goto walk;
}
skb = tcp_sacktag_skip(skb, sk, cache->end_seq);
cache++;
continue;
}
if (!before(start_seq, tcp_highest_sack_seq(tp))) {
skb = tcp_highest_sack(sk);
if (!skb)
break;
}
skb = tcp_sacktag_skip(skb, sk, start_seq);
walk:
skb = tcp_sacktag_walk(skb, sk, next_dup, state,
start_seq, end_seq, dup_sack);
advance_sp:
i++;
}
for (i = 0; i < ARRAY_SIZE(tp->recv_sack_cache) - used_sacks; i++) {
tp->recv_sack_cache[i].start_seq = 0;
tp->recv_sack_cache[i].end_seq = 0;
}
for (j = 0; j < used_sacks; j++)
tp->recv_sack_cache[i++] = sp[j];
if (inet_csk(sk)->icsk_ca_state != TCP_CA_Loss || tp->undo_marker)
tcp_check_sack_reordering(sk, state->reord, 0);
tcp_verify_left_out(tp);
out:
#if FASTRETRANS_DEBUG > 0
WARN_ON((int)tp->sacked_out < 0);
WARN_ON((int)tp->lost_out < 0);
WARN_ON((int)tp->retrans_out < 0);
WARN_ON((int)tcp_packets_in_flight(tp) < 0);
#endif
return state->flag;
}
static bool tcp_limit_reno_sacked(struct tcp_sock *tp)
{
u32 holes;
holes = max(tp->lost_out, 1U);
holes = min(holes, tp->packets_out);
if ((tp->sacked_out + holes) > tp->packets_out) {
tp->sacked_out = tp->packets_out - holes;
return true;
}
return false;
}
static void tcp_check_reno_reordering(struct sock *sk, const int addend)
{
struct tcp_sock *tp = tcp_sk(sk);
if (!tcp_limit_reno_sacked(tp))
return;
tp->reordering = min_t(u32, tp->packets_out + addend,
READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_max_reordering));
tp->reord_seen++;
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPRENOREORDER);
}
static void tcp_add_reno_sack(struct sock *sk, int num_dupack, bool ece_ack)
{
if (num_dupack) {
struct tcp_sock *tp = tcp_sk(sk);
u32 prior_sacked = tp->sacked_out;
s32 delivered;
tp->sacked_out += num_dupack;
tcp_check_reno_reordering(sk, 0);
delivered = tp->sacked_out - prior_sacked;
if (delivered > 0)
tcp_count_delivered(tp, delivered, ece_ack);
tcp_verify_left_out(tp);
}
}
static void tcp_remove_reno_sacks(struct sock *sk, int acked, bool ece_ack)
{
struct tcp_sock *tp = tcp_sk(sk);
if (acked > 0) {
tcp_count_delivered(tp, max_t(int, acked - tp->sacked_out, 1),
ece_ack);
if (acked - 1 >= tp->sacked_out)
tp->sacked_out = 0;
else
tp->sacked_out -= acked - 1;
}
tcp_check_reno_reordering(sk, acked);
tcp_verify_left_out(tp);
}
static inline void tcp_reset_reno_sack(struct tcp_sock *tp)
{
tp->sacked_out = 0;
}
void tcp_clear_retrans(struct tcp_sock *tp)
{
tp->retrans_out = 0;
tp->lost_out = 0;
tp->undo_marker = 0;
tp->undo_retrans = -1;
tp->sacked_out = 0;
}
static inline void tcp_init_undo(struct tcp_sock *tp)
{
tp->undo_marker = tp->snd_una;
tp->undo_retrans = tp->retrans_out ? : -1;
}
static bool tcp_is_rack(const struct sock *sk)
{
return READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_recovery) &
TCP_RACK_LOSS_DETECTION;
}
static void tcp_timeout_mark_lost(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *skb, *head;
bool is_reneg;
head = tcp_rtx_queue_head(sk);
is_reneg = head && (TCP_SKB_CB(head)->sacked & TCPCB_SACKED_ACKED);
if (is_reneg) {
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPSACKRENEGING);
tp->sacked_out = 0;
tp->is_sack_reneg = 1;
} else if (tcp_is_reno(tp)) {
tcp_reset_reno_sack(tp);
}
skb = head;
skb_rbtree_walk_from(skb) {
if (is_reneg)
TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_ACKED;
else if (tcp_is_rack(sk) && skb != head &&
tcp_rack_skb_timeout(tp, skb, 0) > 0)
continue;
tcp_mark_skb_lost(sk, skb);
}
tcp_verify_left_out(tp);
tcp_clear_all_retrans_hints(tp);
}
void tcp_enter_loss(struct sock *sk)
{
const struct inet_connection_sock *icsk = inet_csk(sk);
struct tcp_sock *tp = tcp_sk(sk);
struct net *net = sock_net(sk);
bool new_recovery = icsk->icsk_ca_state < TCP_CA_Recovery;
u8 reordering;
tcp_timeout_mark_lost(sk);
if (icsk->icsk_ca_state <= TCP_CA_Disorder ||
!after(tp->high_seq, tp->snd_una) ||
(icsk->icsk_ca_state == TCP_CA_Loss && !icsk->icsk_retransmits)) {
tp->prior_ssthresh = tcp_current_ssthresh(sk);
tp->prior_cwnd = tcp_snd_cwnd(tp);
tp->snd_ssthresh = icsk->icsk_ca_ops->ssthresh(sk);
tcp_ca_event(sk, CA_EVENT_LOSS);
tcp_init_undo(tp);
}
tcp_snd_cwnd_set(tp, tcp_packets_in_flight(tp) + 1);
tp->snd_cwnd_cnt = 0;
tp->snd_cwnd_stamp = tcp_jiffies32;
reordering = READ_ONCE(net->ipv4.sysctl_tcp_reordering);
if (icsk->icsk_ca_state <= TCP_CA_Disorder &&
tp->sacked_out >= reordering)
tp->reordering = min_t(unsigned int, tp->reordering,
reordering);
tcp_set_ca_state(sk, TCP_CA_Loss);
tp->high_seq = tp->snd_nxt;
tcp_ecn_queue_cwr(tp);
tp->frto = READ_ONCE(net->ipv4.sysctl_tcp_frto) &&
(new_recovery || icsk->icsk_retransmits) &&
!inet_csk(sk)->icsk_mtup.probe_size;
}
static bool tcp_check_sack_reneging(struct sock *sk, int *ack_flag)
{
if (*ack_flag & FLAG_SACK_RENEGING &&
*ack_flag & FLAG_SND_UNA_ADVANCED) {
struct tcp_sock *tp = tcp_sk(sk);
unsigned long delay = max(usecs_to_jiffies(tp->srtt_us >> 4),
msecs_to_jiffies(10));
inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
delay, TCP_RTO_MAX);
*ack_flag &= ~FLAG_SET_XMIT_TIMER;
return true;
}
return false;
}
static inline int tcp_dupack_heuristics(const struct tcp_sock *tp)
{
return tp->sacked_out + 1;
}
static bool tcp_time_to_recover(struct sock *sk, int flag)
{
struct tcp_sock *tp = tcp_sk(sk);
if (tp->lost_out)
return true;
if (!tcp_is_rack(sk) && tcp_dupack_heuristics(tp) > tp->reordering)
return true;
return false;
}
static void tcp_mark_head_lost(struct sock *sk, int packets, int mark_head)
{
struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *skb;
int cnt;
const u32 loss_high = tp->snd_nxt;
WARN_ON(packets > tp->packets_out);
skb = tp->lost_skb_hint;
if (skb) {
if (mark_head && after(TCP_SKB_CB(skb)->seq, tp->snd_una))
return;
cnt = tp->lost_cnt_hint;
} else {
skb = tcp_rtx_queue_head(sk);
cnt = 0;
}
skb_rbtree_walk_from(skb) {
tp->lost_skb_hint = skb;
tp->lost_cnt_hint = cnt;
if (after(TCP_SKB_CB(skb)->end_seq, loss_high))
break;
if (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)
cnt += tcp_skb_pcount(skb);
if (cnt > packets)
break;
if (!(TCP_SKB_CB(skb)->sacked & TCPCB_LOST))
tcp_mark_skb_lost(sk, skb);
if (mark_head)
break;
}
tcp_verify_left_out(tp);
}
static void tcp_update_scoreboard(struct sock *sk, int fast_rexmit)
{
struct tcp_sock *tp = tcp_sk(sk);
if (tcp_is_sack(tp)) {
int sacked_upto = tp->sacked_out - tp->reordering;
if (sacked_upto >= 0)
tcp_mark_head_lost(sk, sacked_upto, 0);
else if (fast_rexmit)
tcp_mark_head_lost(sk, 1, 1);
}
}
static bool tcp_tsopt_ecr_before(const struct tcp_sock *tp, u32 when)
{
return tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr &&
before(tp->rx_opt.rcv_tsecr, when);
}
static bool tcp_skb_spurious_retrans(const struct tcp_sock *tp,
const struct sk_buff *skb)
{
return (TCP_SKB_CB(skb)->sacked & TCPCB_RETRANS) &&
tcp_tsopt_ecr_before(tp, tcp_skb_timestamp(skb));
}
static inline bool tcp_packet_delayed(const struct tcp_sock *tp)
{
return tp->retrans_stamp &&
tcp_tsopt_ecr_before(tp, tp->retrans_stamp);
}
static bool tcp_any_retrans_done(const struct sock *sk)
{
const struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *skb;
if (tp->retrans_out)
return true;
skb = tcp_rtx_queue_head(sk);
if (unlikely(skb && TCP_SKB_CB(skb)->sacked & TCPCB_EVER_RETRANS))
return true;
return false;
}
static void DBGUNDO(struct sock *sk, const char *msg)
{
#if FASTRETRANS_DEBUG > 1
struct tcp_sock *tp = tcp_sk(sk);
struct inet_sock *inet = inet_sk(sk);
if (sk->sk_family == AF_INET) {
pr_debug("Undo %s %pI4/%u c%u l%u ss%u/%u p%u\n",
msg,
&inet->inet_daddr, ntohs(inet->inet_dport),
tcp_snd_cwnd(tp), tcp_left_out(tp),
tp->snd_ssthresh, tp->prior_ssthresh,
tp->packets_out);
}
#if IS_ENABLED(CONFIG_IPV6)
else if (sk->sk_family == AF_INET6) {
pr_debug("Undo %s %pI6/%u c%u l%u ss%u/%u p%u\n",
msg,
&sk->sk_v6_daddr, ntohs(inet->inet_dport),
tcp_snd_cwnd(tp), tcp_left_out(tp),
tp->snd_ssthresh, tp->prior_ssthresh,
tp->packets_out);
}
#endif
#endif
}
static void tcp_undo_cwnd_reduction(struct sock *sk, bool unmark_loss)
{
struct tcp_sock *tp = tcp_sk(sk);
if (unmark_loss) {
struct sk_buff *skb;
skb_rbtree_walk(skb, &sk->tcp_rtx_queue) {
TCP_SKB_CB(skb)->sacked &= ~TCPCB_LOST;
}
tp->lost_out = 0;
tcp_clear_all_retrans_hints(tp);
}
if (tp->prior_ssthresh) {
const struct inet_connection_sock *icsk = inet_csk(sk);
tcp_snd_cwnd_set(tp, icsk->icsk_ca_ops->undo_cwnd(sk));
if (tp->prior_ssthresh > tp->snd_ssthresh) {
tp->snd_ssthresh = tp->prior_ssthresh;
tcp_ecn_withdraw_cwr(tp);
}
}
tp->snd_cwnd_stamp = tcp_jiffies32;
tp->undo_marker = 0;
tp->rack.advanced = 1;
}
static inline bool tcp_may_undo(const struct tcp_sock *tp)
{
return tp->undo_marker && (!tp->undo_retrans || tcp_packet_delayed(tp));
}
static bool tcp_is_non_sack_preventing_reopen(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);
if (tp->snd_una == tp->high_seq && tcp_is_reno(tp)) {
if (!tcp_any_retrans_done(sk))
tp->retrans_stamp = 0;
return true;
}
return false;
}
static bool tcp_try_undo_recovery(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);
if (tcp_may_undo(tp)) {
int mib_idx;
DBGUNDO(sk, inet_csk(sk)->icsk_ca_state == TCP_CA_Loss ? "loss" : "retrans");
tcp_undo_cwnd_reduction(sk, false);
if (inet_csk(sk)->icsk_ca_state == TCP_CA_Loss)
mib_idx = LINUX_MIB_TCPLOSSUNDO;
else
mib_idx = LINUX_MIB_TCPFULLUNDO;
NET_INC_STATS(sock_net(sk), mib_idx);
} else if (tp->rack.reo_wnd_persist) {
tp->rack.reo_wnd_persist--;
}
if (tcp_is_non_sack_preventing_reopen(sk))
return true;
tcp_set_ca_state(sk, TCP_CA_Open);
tp->is_sack_reneg = 0;
return false;
}
static bool tcp_try_undo_dsack(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);
if (tp->undo_marker && !tp->undo_retrans) {
tp->rack.reo_wnd_persist = min(TCP_RACK_RECOVERY_THRESH,
tp->rack.reo_wnd_persist + 1);
DBGUNDO(sk, "D-SACK");
tcp_undo_cwnd_reduction(sk, false);
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPDSACKUNDO);
return true;
}
return false;
}
static bool tcp_try_undo_loss(struct sock *sk, bool frto_undo)
{
struct tcp_sock *tp = tcp_sk(sk);
if (frto_undo || tcp_may_undo(tp)) {
tcp_undo_cwnd_reduction(sk, true);
DBGUNDO(sk, "partial loss");
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPLOSSUNDO);
if (frto_undo)
NET_INC_STATS(sock_net(sk),
LINUX_MIB_TCPSPURIOUSRTOS);
inet_csk(sk)->icsk_retransmits = 0;
if (tcp_is_non_sack_preventing_reopen(sk))
return true;
if (frto_undo || tcp_is_sack(tp)) {
tcp_set_ca_state(sk, TCP_CA_Open);
tp->is_sack_reneg = 0;
}
return true;
}
return false;
}
static void tcp_init_cwnd_reduction(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);
tp->high_seq = tp->snd_nxt;
tp->tlp_high_seq = 0;
tp->snd_cwnd_cnt = 0;
tp->prior_cwnd = tcp_snd_cwnd(tp);
tp->prr_delivered = 0;
tp->prr_out = 0;
tp->snd_ssthresh = inet_csk(sk)->icsk_ca_ops->ssthresh(sk);
tcp_ecn_queue_cwr(tp);
}
void tcp_cwnd_reduction(struct sock *sk, int newly_acked_sacked, int newly_lost, int flag)
{
struct tcp_sock *tp = tcp_sk(sk);
int sndcnt = 0;
int delta = tp->snd_ssthresh - tcp_packets_in_flight(tp);
if (newly_acked_sacked <= 0 || WARN_ON_ONCE(!tp->prior_cwnd))
return;
tp->prr_delivered += newly_acked_sacked;
if (delta < 0) {
u64 dividend = (u64)tp->snd_ssthresh * tp->prr_delivered +
tp->prior_cwnd - 1;
sndcnt = div_u64(dividend, tp->prior_cwnd) - tp->prr_out;
} else {
sndcnt = max_t(int, tp->prr_delivered - tp->prr_out,
newly_acked_sacked);
if (flag & FLAG_SND_UNA_ADVANCED && !newly_lost)
sndcnt++;
sndcnt = min(delta, sndcnt);
}
sndcnt = max(sndcnt, (tp->prr_out ? 0 : 1));
tcp_snd_cwnd_set(tp, tcp_packets_in_flight(tp) + sndcnt);
}
static inline void tcp_end_cwnd_reduction(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);
if (inet_csk(sk)->icsk_ca_ops->cong_control)
return;
if (tp->snd_ssthresh < TCP_INFINITE_SSTHRESH &&
(inet_csk(sk)->icsk_ca_state == TCP_CA_CWR || tp->undo_marker)) {
tcp_snd_cwnd_set(tp, tp->snd_ssthresh);
tp->snd_cwnd_stamp = tcp_jiffies32;
}
tcp_ca_event(sk, CA_EVENT_COMPLETE_CWR);
}
void tcp_enter_cwr(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);
tp->prior_ssthresh = 0;
if (inet_csk(sk)->icsk_ca_state < TCP_CA_CWR) {
tp->undo_marker = 0;
tcp_init_cwnd_reduction(sk);
tcp_set_ca_state(sk, TCP_CA_CWR);
}
}
EXPORT_SYMBOL(tcp_enter_cwr);
static void tcp_try_keep_open(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);
int state = TCP_CA_Open;
if (tcp_left_out(tp) || tcp_any_retrans_done(sk))
state = TCP_CA_Disorder;
if (inet_csk(sk)->icsk_ca_state != state) {
tcp_set_ca_state(sk, state);
tp->high_seq = tp->snd_nxt;
}
}
static void tcp_try_to_open(struct sock *sk, int flag)
{
struct tcp_sock *tp = tcp_sk(sk);
tcp_verify_left_out(tp);
if (!tcp_any_retrans_done(sk))
tp->retrans_stamp = 0;
if (flag & FLAG_ECE)
tcp_enter_cwr(sk);
if (inet_csk(sk)->icsk_ca_state != TCP_CA_CWR) {
tcp_try_keep_open(sk);
}
}
static void tcp_mtup_probe_failed(struct sock *sk)
{
struct inet_connection_sock *icsk = inet_csk(sk);
icsk->icsk_mtup.search_high = icsk->icsk_mtup.probe_size - 1;
icsk->icsk_mtup.probe_size = 0;
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMTUPFAIL);
}
static void tcp_mtup_probe_success(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);
struct inet_connection_sock *icsk = inet_csk(sk);
u64 val;
tp->prior_ssthresh = tcp_current_ssthresh(sk);
val = (u64)tcp_snd_cwnd(tp) * tcp_mss_to_mtu(sk, tp->mss_cache);
do_div(val, icsk->icsk_mtup.probe_size);
DEBUG_NET_WARN_ON_ONCE((u32)val != val);
tcp_snd_cwnd_set(tp, max_t(u32, 1U, val));
tp->snd_cwnd_cnt = 0;
tp->snd_cwnd_stamp = tcp_jiffies32;
tp->snd_ssthresh = tcp_current_ssthresh(sk);
icsk->icsk_mtup.search_low = icsk->icsk_mtup.probe_size;
icsk->icsk_mtup.probe_size = 0;
tcp_sync_mss(sk, icsk->icsk_pmtu_cookie);
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMTUPSUCCESS);
}
void tcp_simple_retransmit(struct sock *sk)
{
const struct inet_connection_sock *icsk = inet_csk(sk);
struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *skb;
int mss;
if (tp->syn_data && sk->sk_state == TCP_SYN_SENT)
mss = -1;
else
mss = tcp_current_mss(sk);
skb_rbtree_walk(skb, &sk->tcp_rtx_queue) {
if (tcp_skb_seglen(skb) > mss)
tcp_mark_skb_lost(sk, skb);
}
tcp_clear_retrans_hints_partial(tp);
if (!tp->lost_out)
return;
if (tcp_is_reno(tp))
tcp_limit_reno_sacked(tp);
tcp_verify_left_out(tp);
if (icsk->icsk_ca_state != TCP_CA_Loss) {
tp->high_seq = tp->snd_nxt;
tp->snd_ssthresh = tcp_current_ssthresh(sk);
tp->prior_ssthresh = 0;
tp->undo_marker = 0;
tcp_set_ca_state(sk, TCP_CA_Loss);
}
tcp_xmit_retransmit_queue(sk);
}
EXPORT_SYMBOL(tcp_simple_retransmit);
void tcp_enter_recovery(struct sock *sk, bool ece_ack)
{
struct tcp_sock *tp = tcp_sk(sk);
int mib_idx;
if (tcp_is_reno(tp))
mib_idx = LINUX_MIB_TCPRENORECOVERY;
else
mib_idx = LINUX_MIB_TCPSACKRECOVERY;
NET_INC_STATS(sock_net(sk), mib_idx);
tp->prior_ssthresh = 0;
tcp_init_undo(tp);
if (!tcp_in_cwnd_reduction(sk)) {
if (!ece_ack)
tp->prior_ssthresh = tcp_current_ssthresh(sk);
tcp_init_cwnd_reduction(sk);
}
tcp_set_ca_state(sk, TCP_CA_Recovery);
}
static void tcp_process_loss(struct sock *sk, int flag, int num_dupack,
int *rexmit)
{
struct tcp_sock *tp = tcp_sk(sk);
bool recovered = !before(tp->snd_una, tp->high_seq);
if ((flag & FLAG_SND_UNA_ADVANCED || rcu_access_pointer(tp->fastopen_rsk)) &&
tcp_try_undo_loss(sk, false))
return;
if (tp->frto) {
if ((flag & FLAG_ORIG_SACK_ACKED) &&
tcp_try_undo_loss(sk, true))
return;
if (after(tp->snd_nxt, tp->high_seq)) {
if (flag & FLAG_DATA_SACKED || num_dupack)
tp->frto = 0;
} else if (flag & FLAG_SND_UNA_ADVANCED && !recovered) {
tp->high_seq = tp->snd_nxt;
if (!tcp_write_queue_empty(sk) &&
after(tcp_wnd_end(tp), tp->snd_nxt)) {
*rexmit = REXMIT_NEW;
return;
}
tp->frto = 0;
}
}
if (recovered) {
tcp_try_undo_recovery(sk);
return;
}
if (tcp_is_reno(tp)) {
if (after(tp->snd_nxt, tp->high_seq) && num_dupack)
tcp_add_reno_sack(sk, num_dupack, flag & FLAG_ECE);
else if (flag & FLAG_SND_UNA_ADVANCED)
tcp_reset_reno_sack(tp);
}
*rexmit = REXMIT_LOST;
}
static bool tcp_force_fast_retransmit(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);
return after(tcp_highest_sack_seq(tp),
tp->snd_una + tp->reordering * tp->mss_cache);
}
static bool tcp_try_undo_partial(struct sock *sk, u32 prior_snd_una,
bool *do_lost)
{
struct tcp_sock *tp = tcp_sk(sk);
if (tp->undo_marker && tcp_packet_delayed(tp)) {
tcp_check_sack_reordering(sk, prior_snd_una, 1);
if (tp->retrans_out)
return true;
if (!tcp_any_retrans_done(sk))
tp->retrans_stamp = 0;
DBGUNDO(sk, "partial recovery");
tcp_undo_cwnd_reduction(sk, true);
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPPARTIALUNDO);
tcp_try_keep_open(sk);
} else {
*do_lost = tcp_force_fast_retransmit(sk);
}
return false;
}
static void tcp_identify_packet_loss(struct sock *sk, int *ack_flag)
{
struct tcp_sock *tp = tcp_sk(sk);
if (tcp_rtx_queue_empty(sk))
return;
if (unlikely(tcp_is_reno(tp))) {
tcp_newreno_mark_lost(sk, *ack_flag & FLAG_SND_UNA_ADVANCED);
} else if (tcp_is_rack(sk)) {
u32 prior_retrans = tp->retrans_out;
if (tcp_rack_mark_lost(sk))
*ack_flag &= ~FLAG_SET_XMIT_TIMER;
if (prior_retrans > tp->retrans_out)
*ack_flag |= FLAG_LOST_RETRANS;
}
}
static void tcp_fastretrans_alert(struct sock *sk, const u32 prior_snd_una,
int num_dupack, int *ack_flag, int *rexmit)
{
struct inet_connection_sock *icsk = inet_csk(sk);
struct tcp_sock *tp = tcp_sk(sk);
int fast_rexmit = 0, flag = *ack_flag;
bool ece_ack = flag & FLAG_ECE;
bool do_lost = num_dupack || ((flag & FLAG_DATA_SACKED) &&
tcp_force_fast_retransmit(sk));
if (!tp->packets_out && tp->sacked_out)
tp->sacked_out = 0;
if (ece_ack)
tp->prior_ssthresh = 0;
if (tcp_check_sack_reneging(sk, ack_flag))
return;
tcp_verify_left_out(tp);
if (icsk->icsk_ca_state == TCP_CA_Open) {
WARN_ON(tp->retrans_out != 0 && !tp->syn_data);
tp->retrans_stamp = 0;
} else if (!before(tp->snd_una, tp->high_seq)) {
switch (icsk->icsk_ca_state) {
case TCP_CA_CWR:
if (tp->snd_una != tp->high_seq) {
tcp_end_cwnd_reduction(sk);
tcp_set_ca_state(sk, TCP_CA_Open);
}
break;
case TCP_CA_Recovery:
if (tcp_is_reno(tp))
tcp_reset_reno_sack(tp);
if (tcp_try_undo_recovery(sk))
return;
tcp_end_cwnd_reduction(sk);
break;
}
}
switch (icsk->icsk_ca_state) {
case TCP_CA_Recovery:
if (!(flag & FLAG_SND_UNA_ADVANCED)) {
if (tcp_is_reno(tp))
tcp_add_reno_sack(sk, num_dupack, ece_ack);
} else if (tcp_try_undo_partial(sk, prior_snd_una, &do_lost))
return;
if (tcp_try_undo_dsack(sk))
tcp_try_keep_open(sk);
tcp_identify_packet_loss(sk, ack_flag);
if (icsk->icsk_ca_state != TCP_CA_Recovery) {
if (!tcp_time_to_recover(sk, flag))
return;
tcp_enter_recovery(sk, ece_ack);
}
break;
case TCP_CA_Loss:
tcp_process_loss(sk, flag, num_dupack, rexmit);
tcp_identify_packet_loss(sk, ack_flag);
if (!(icsk->icsk_ca_state == TCP_CA_Open ||
(*ack_flag & FLAG_LOST_RETRANS)))
return;
fallthrough;
default:
if (tcp_is_reno(tp)) {
if (flag & FLAG_SND_UNA_ADVANCED)
tcp_reset_reno_sack(tp);
tcp_add_reno_sack(sk, num_dupack, ece_ack);
}
if (icsk->icsk_ca_state <= TCP_CA_Disorder)
tcp_try_undo_dsack(sk);
tcp_identify_packet_loss(sk, ack_flag);
if (!tcp_time_to_recover(sk, flag)) {
tcp_try_to_open(sk, flag);
return;
}
if (icsk->icsk_ca_state < TCP_CA_CWR &&
icsk->icsk_mtup.probe_size &&
tp->snd_una == tp->mtu_probe.probe_seq_start) {
tcp_mtup_probe_failed(sk);
tcp_snd_cwnd_set(tp, tcp_snd_cwnd(tp) + 1);
tcp_simple_retransmit(sk);
return;
}
tcp_enter_recovery(sk, ece_ack);
fast_rexmit = 1;
}
if (!tcp_is_rack(sk) && do_lost)
tcp_update_scoreboard(sk, fast_rexmit);
*rexmit = REXMIT_LOST;
}
static void tcp_update_rtt_min(struct sock *sk, u32 rtt_us, const int flag)
{
u32 wlen = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_min_rtt_wlen) * HZ;
struct tcp_sock *tp = tcp_sk(sk);
if ((flag & FLAG_ACK_MAYBE_DELAYED) && rtt_us > tcp_min_rtt(tp)) {
return;
}
minmax_running_min(&tp->rtt_min, wlen, tcp_jiffies32,
rtt_us ? : jiffies_to_usecs(1));
}
static bool tcp_ack_update_rtt(struct sock *sk, const int flag,
long seq_rtt_us, long sack_rtt_us,
long ca_rtt_us, struct rate_sample *rs)
{
const struct tcp_sock *tp = tcp_sk(sk);
if (seq_rtt_us < 0)
seq_rtt_us = sack_rtt_us;
if (seq_rtt_us < 0 && tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr &&
flag & FLAG_ACKED) {
u32 delta = tcp_time_stamp(tp) - tp->rx_opt.rcv_tsecr;
if (likely(delta < INT_MAX / (USEC_PER_SEC / TCP_TS_HZ))) {
if (!delta)
delta = 1;
seq_rtt_us = delta * (USEC_PER_SEC / TCP_TS_HZ);
ca_rtt_us = seq_rtt_us;
}
}
rs->rtt_us = ca_rtt_us;
if (seq_rtt_us < 0)
return false;
tcp_update_rtt_min(sk, ca_rtt_us, flag);
tcp_rtt_estimator(sk, seq_rtt_us);
tcp_set_rto(sk);
inet_csk(sk)->icsk_backoff = 0;
return true;
}
void tcp_synack_rtt_meas(struct sock *sk, struct request_sock *req)
{
struct rate_sample rs;
long rtt_us = -1L;
if (req && !req->num_retrans && tcp_rsk(req)->snt_synack)
rtt_us = tcp_stamp_us_delta(tcp_clock_us(), tcp_rsk(req)->snt_synack);
tcp_ack_update_rtt(sk, FLAG_SYN_ACKED, rtt_us, -1L, rtt_us, &rs);
}
static void tcp_cong_avoid(struct sock *sk, u32 ack, u32 acked)
{
const struct inet_connection_sock *icsk = inet_csk(sk);
icsk->icsk_ca_ops->cong_avoid(sk, ack, acked);
tcp_sk(sk)->snd_cwnd_stamp = tcp_jiffies32;
}
void tcp_rearm_rto(struct sock *sk)
{
const struct inet_connection_sock *icsk = inet_csk(sk);
struct tcp_sock *tp = tcp_sk(sk);
if (rcu_access_pointer(tp->fastopen_rsk))
return;
if (!tp->packets_out) {
inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
} else {
u32 rto = inet_csk(sk)->icsk_rto;
if (icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT ||
icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
s64 delta_us = tcp_rto_delta_us(sk);
rto = usecs_to_jiffies(max_t(int, delta_us, 1));
}
tcp_reset_xmit_timer(sk, ICSK_TIME_RETRANS, rto,
TCP_RTO_MAX);
}
}
static void tcp_set_xmit_timer(struct sock *sk)
{
if (!tcp_schedule_loss_probe(sk, true))
tcp_rearm_rto(sk);
}
static u32 tcp_tso_acked(struct sock *sk, struct sk_buff *skb)
{
struct tcp_sock *tp = tcp_sk(sk);
u32 packets_acked;
BUG_ON(!after(TCP_SKB_CB(skb)->end_seq, tp->snd_una));
packets_acked = tcp_skb_pcount(skb);
if (tcp_trim_head(sk, skb, tp->snd_una - TCP_SKB_CB(skb)->seq))
return 0;
packets_acked -= tcp_skb_pcount(skb);
if (packets_acked) {
BUG_ON(tcp_skb_pcount(skb) == 0);
BUG_ON(!before(TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq));
}
return packets_acked;
}
static void tcp_ack_tstamp(struct sock *sk, struct sk_buff *skb,
const struct sk_buff *ack_skb, u32 prior_snd_una)
{
const struct skb_shared_info *shinfo;
if (likely(!TCP_SKB_CB(skb)->txstamp_ack))
return;
shinfo = skb_shinfo(skb);
if (!before(shinfo->tskey, prior_snd_una) &&
before(shinfo->tskey, tcp_sk(sk)->snd_una)) {
tcp_skb_tsorted_save(skb) {
__skb_tstamp_tx(skb, ack_skb, NULL, sk, SCM_TSTAMP_ACK);
} tcp_skb_tsorted_restore(skb);
}
}
static int tcp_clean_rtx_queue(struct sock *sk, const struct sk_buff *ack_skb,
u32 prior_fack, u32 prior_snd_una,
struct tcp_sacktag_state *sack, bool ece_ack)
{
const struct inet_connection_sock *icsk = inet_csk(sk);
u64 first_ackt, last_ackt;
struct tcp_sock *tp = tcp_sk(sk);
u32 prior_sacked = tp->sacked_out;
u32 reord = tp->snd_nxt;
struct sk_buff *skb, *next;
bool fully_acked = true;
long sack_rtt_us = -1L;
long seq_rtt_us = -1L;
long ca_rtt_us = -1L;
u32 pkts_acked = 0;
bool rtt_update;
int flag = 0;
first_ackt = 0;
for (skb = skb_rb_first(&sk->tcp_rtx_queue); skb; skb = next) {
struct tcp_skb_cb *scb = TCP_SKB_CB(skb);
const u32 start_seq = scb->seq;
u8 sacked = scb->sacked;
u32 acked_pcount;
if (after(scb->end_seq, tp->snd_una)) {
if (tcp_skb_pcount(skb) == 1 ||
!after(tp->snd_una, scb->seq))
break;
acked_pcount = tcp_tso_acked(sk, skb);
if (!acked_pcount)
break;
fully_acked = false;
} else {
acked_pcount = tcp_skb_pcount(skb);
}
if (unlikely(sacked & TCPCB_RETRANS)) {
if (sacked & TCPCB_SACKED_RETRANS)
tp->retrans_out -= acked_pcount;
flag |= FLAG_RETRANS_DATA_ACKED;
} else if (!(sacked & TCPCB_SACKED_ACKED)) {
last_ackt = tcp_skb_timestamp_us(skb);
WARN_ON_ONCE(last_ackt == 0);
if (!first_ackt)
first_ackt = last_ackt;
if (before(start_seq, reord))
reord = start_seq;
if (!after(scb->end_seq, tp->high_seq))
flag |= FLAG_ORIG_SACK_ACKED;
}
if (sacked & TCPCB_SACKED_ACKED) {
tp->sacked_out -= acked_pcount;
} else if (tcp_is_sack(tp)) {
tcp_count_delivered(tp, acked_pcount, ece_ack);
if (!tcp_skb_spurious_retrans(tp, skb))
tcp_rack_advance(tp, sacked, scb->end_seq,
tcp_skb_timestamp_us(skb));
}
if (sacked & TCPCB_LOST)
tp->lost_out -= acked_pcount;
tp->packets_out -= acked_pcount;
pkts_acked += acked_pcount;
tcp_rate_skb_delivered(sk, skb, sack->rate);
if (likely(!(scb->tcp_flags & TCPHDR_SYN))) {
flag |= FLAG_DATA_ACKED;
} else {
flag |= FLAG_SYN_ACKED;
tp->retrans_stamp = 0;
}
if (!fully_acked)
break;
tcp_ack_tstamp(sk, skb, ack_skb, prior_snd_una);
next = skb_rb_next(skb);
if (unlikely(skb == tp->retransmit_skb_hint))
tp->retransmit_skb_hint = NULL;
if (unlikely(skb == tp->lost_skb_hint))
tp->lost_skb_hint = NULL;
tcp_highest_sack_replace(sk, skb, next);
tcp_rtx_queue_unlink_and_free(skb, sk);
}
if (!skb)
tcp_chrono_stop(sk, TCP_CHRONO_BUSY);
if (likely(between(tp->snd_up, prior_snd_una, tp->snd_una)))
tp->snd_up = tp->snd_una;
if (skb) {
tcp_ack_tstamp(sk, skb, ack_skb, prior_snd_una);
if (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)
flag |= FLAG_SACK_RENEGING;
}
if (likely(first_ackt) && !(flag & FLAG_RETRANS_DATA_ACKED)) {
seq_rtt_us = tcp_stamp_us_delta(tp->tcp_mstamp, first_ackt);
ca_rtt_us = tcp_stamp_us_delta(tp->tcp_mstamp, last_ackt);
if (pkts_acked == 1 && fully_acked && !prior_sacked &&
(tp->snd_una - prior_snd_una) < tp->mss_cache &&
sack->rate->prior_delivered + 1 == tp->delivered &&
!(flag & (FLAG_CA_ALERT | FLAG_SYN_ACKED))) {
flag |= FLAG_ACK_MAYBE_DELAYED;
}
}
if (sack->first_sackt) {
sack_rtt_us = tcp_stamp_us_delta(tp->tcp_mstamp, sack->first_sackt);
ca_rtt_us = tcp_stamp_us_delta(tp->tcp_mstamp, sack->last_sackt);
}
rtt_update = tcp_ack_update_rtt(sk, flag, seq_rtt_us, sack_rtt_us,
ca_rtt_us, sack->rate);
if (flag & FLAG_ACKED) {
flag |= FLAG_SET_XMIT_TIMER;
if (unlikely(icsk->icsk_mtup.probe_size &&
!after(tp->mtu_probe.probe_seq_end, tp->snd_una))) {
tcp_mtup_probe_success(sk);
}
if (tcp_is_reno(tp)) {
tcp_remove_reno_sacks(sk, pkts_acked, ece_ack);
if (flag & FLAG_RETRANS_DATA_ACKED)
flag &= ~FLAG_ORIG_SACK_ACKED;
} else {
int delta;
if (before(reord, prior_fack))
tcp_check_sack_reordering(sk, reord, 0);
delta = prior_sacked - tp->sacked_out;
tp->lost_cnt_hint -= min(tp->lost_cnt_hint, delta);
}
} else if (skb && rtt_update && sack_rtt_us >= 0 &&
sack_rtt_us > tcp_stamp_us_delta(tp->tcp_mstamp,
tcp_skb_timestamp_us(skb))) {
flag |= FLAG_SET_XMIT_TIMER;
}
if (icsk->icsk_ca_ops->pkts_acked) {
struct ack_sample sample = { .pkts_acked = pkts_acked,
.rtt_us = sack->rate->rtt_us };
sample.in_flight = tp->mss_cache *
(tp->delivered - sack->rate->prior_delivered);
icsk->icsk_ca_ops->pkts_acked(sk, &sample);
}
#if FASTRETRANS_DEBUG > 0
WARN_ON((int)tp->sacked_out < 0);
WARN_ON((int)tp->lost_out < 0);
WARN_ON((int)tp->retrans_out < 0);
if (!tp->packets_out && tcp_is_sack(tp)) {
icsk = inet_csk(sk);
if (tp->lost_out) {
pr_debug("Leak l=%u %d\n",
tp->lost_out, icsk->icsk_ca_state);
tp->lost_out = 0;
}
if (tp->sacked_out) {
pr_debug("Leak s=%u %d\n",
tp->sacked_out, icsk->icsk_ca_state);
tp->sacked_out = 0;
}
if (tp->retrans_out) {
pr_debug("Leak r=%u %d\n",
tp->retrans_out, icsk->icsk_ca_state);
tp->retrans_out = 0;
}
}
#endif
return flag;
}
static void tcp_ack_probe(struct sock *sk)
{
struct inet_connection_sock *icsk = inet_csk(sk);
struct sk_buff *head = tcp_send_head(sk);
const struct tcp_sock *tp = tcp_sk(sk);
if (!head)
return;
if (!after(TCP_SKB_CB(head)->end_seq, tcp_wnd_end(tp))) {
icsk->icsk_backoff = 0;
icsk->icsk_probes_tstamp = 0;
inet_csk_clear_xmit_timer(sk, ICSK_TIME_PROBE0);
} else {
unsigned long when = tcp_probe0_when(sk, TCP_RTO_MAX);
when = tcp_clamp_probe0_to_user_timeout(sk, when);
tcp_reset_xmit_timer(sk, ICSK_TIME_PROBE0, when, TCP_RTO_MAX);
}
}
static inline bool tcp_ack_is_dubious(const struct sock *sk, const int flag)
{
return !(flag & FLAG_NOT_DUP) || (flag & FLAG_CA_ALERT) ||
inet_csk(sk)->icsk_ca_state != TCP_CA_Open;
}
static inline bool tcp_may_raise_cwnd(const struct sock *sk, const int flag)
{
if (tcp_sk(sk)->reordering >
READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reordering))
return flag & FLAG_FORWARD_PROGRESS;
return flag & FLAG_DATA_ACKED;
}
static void tcp_cong_control(struct sock *sk, u32 ack, u32 acked_sacked,
int flag, const struct rate_sample *rs)
{
const struct inet_connection_sock *icsk = inet_csk(sk);
if (icsk->icsk_ca_ops->cong_control) {
icsk->icsk_ca_ops->cong_control(sk, rs);
return;
}
if (tcp_in_cwnd_reduction(sk)) {
tcp_cwnd_reduction(sk, acked_sacked, rs->losses, flag);
} else if (tcp_may_raise_cwnd(sk, flag)) {
tcp_cong_avoid(sk, ack, acked_sacked);
}
tcp_update_pacing_rate(sk);
}
static inline bool tcp_may_update_window(const struct tcp_sock *tp,
const u32 ack, const u32 ack_seq,
const u32 nwin)
{
return after(ack, tp->snd_una) ||
after(ack_seq, tp->snd_wl1) ||
(ack_seq == tp->snd_wl1 && (nwin > tp->snd_wnd || !nwin));
}
static void tcp_snd_una_update(struct tcp_sock *tp, u32 ack)
{
u32 delta = ack - tp->snd_una;
sock_owned_by_me((struct sock *)tp);
tp->bytes_acked += delta;
tp->snd_una = ack;
}
static void tcp_rcv_nxt_update(struct tcp_sock *tp, u32 seq)
{
u32 delta = seq - tp->rcv_nxt;
sock_owned_by_me((struct sock *)tp);
tp->bytes_received += delta;
WRITE_ONCE(tp->rcv_nxt, seq);
}
static int tcp_ack_update_window(struct sock *sk, const struct sk_buff *skb, u32 ack,
u32 ack_seq)
{
struct tcp_sock *tp = tcp_sk(sk);
int flag = 0;
u32 nwin = ntohs(tcp_hdr(skb)->window);
if (likely(!tcp_hdr(skb)->syn))
nwin <<= tp->rx_opt.snd_wscale;
if (tcp_may_update_window(tp, ack, ack_seq, nwin)) {
flag |= FLAG_WIN_UPDATE;
tcp_update_wl(tp, ack_seq);
if (tp->snd_wnd != nwin) {
tp->snd_wnd = nwin;
tp->pred_flags = 0;
tcp_fast_path_check(sk);
if (!tcp_write_queue_empty(sk))
tcp_slow_start_after_idle_check(sk);
if (nwin > tp->max_window) {
tp->max_window = nwin;
tcp_sync_mss(sk, inet_csk(sk)->icsk_pmtu_cookie);
}
}
}
tcp_snd_una_update(tp, ack);
return flag;
}
static bool __tcp_oow_rate_limited(struct net *net, int mib_idx,
u32 *last_oow_ack_time)
{
u32 val = READ_ONCE(*last_oow_ack_time);
if (val) {
s32 elapsed = (s32)(tcp_jiffies32 - val);
if (0 <= elapsed &&
elapsed < READ_ONCE(net->ipv4.sysctl_tcp_invalid_ratelimit)) {
NET_INC_STATS(net, mib_idx);
return true;
}
}
WRITE_ONCE(*last_oow_ack_time, tcp_jiffies32);
return false;
}
bool tcp_oow_rate_limited(struct net *net, const struct sk_buff *skb,
int mib_idx, u32 *last_oow_ack_time)
{
if ((TCP_SKB_CB(skb)->seq != TCP_SKB_CB(skb)->end_seq) &&
!tcp_hdr(skb)->syn)
return false;
return __tcp_oow_rate_limited(net, mib_idx, last_oow_ack_time);
}
static void tcp_send_challenge_ack(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);
struct net *net = sock_net(sk);
u32 count, now, ack_limit;
if (__tcp_oow_rate_limited(net,
LINUX_MIB_TCPACKSKIPPEDCHALLENGE,
&tp->last_oow_ack_time))
return;
ack_limit = READ_ONCE(net->ipv4.sysctl_tcp_challenge_ack_limit);
if (ack_limit == INT_MAX)
goto send_ack;
now = jiffies / HZ;
if (now != READ_ONCE(net->ipv4.tcp_challenge_timestamp)) {
u32 half = (ack_limit + 1) >> 1;
WRITE_ONCE(net->ipv4.tcp_challenge_timestamp, now);
WRITE_ONCE(net->ipv4.tcp_challenge_count,
get_random_u32_inclusive(half, ack_limit + half - 1));
}
count = READ_ONCE(net->ipv4.tcp_challenge_count);
if (count > 0) {
WRITE_ONCE(net->ipv4.tcp_challenge_count, count - 1);
send_ack:
NET_INC_STATS(net, LINUX_MIB_TCPCHALLENGEACK);
tcp_send_ack(sk);
}
}
static void tcp_store_ts_recent(struct tcp_sock *tp)
{
tp->rx_opt.ts_recent = tp->rx_opt.rcv_tsval;
tp->rx_opt.ts_recent_stamp = ktime_get_seconds();
}
static void tcp_replace_ts_recent(struct tcp_sock *tp, u32 seq)
{
if (tp->rx_opt.saw_tstamp && !after(seq, tp->rcv_wup)) {
if (tcp_paws_check(&tp->rx_opt, 0))
tcp_store_ts_recent(tp);
}
}
static void tcp_process_tlp_ack(struct sock *sk, u32 ack, int flag)
{
struct tcp_sock *tp = tcp_sk(sk);
if (before(ack, tp->tlp_high_seq))
return;
if (!tp->tlp_retrans) {
tp->tlp_high_seq = 0;
} else if (flag & FLAG_DSACK_TLP) {
tp->tlp_high_seq = 0;
} else if (after(ack, tp->tlp_high_seq)) {
tcp_init_cwnd_reduction(sk);
tcp_set_ca_state(sk, TCP_CA_CWR);
tcp_end_cwnd_reduction(sk);
tcp_try_keep_open(sk);
NET_INC_STATS(sock_net(sk),
LINUX_MIB_TCPLOSSPROBERECOVERY);
} else if (!(flag & (FLAG_SND_UNA_ADVANCED |
FLAG_NOT_DUP | FLAG_DATA_SACKED))) {
tp->tlp_high_seq = 0;
}
}
static inline void tcp_in_ack_event(struct sock *sk, u32 flags)
{
const struct inet_connection_sock *icsk = inet_csk(sk);
if (icsk->icsk_ca_ops->in_ack_event)
icsk->icsk_ca_ops->in_ack_event(sk, flags);
}
static void tcp_xmit_recovery(struct sock *sk, int rexmit)
{
struct tcp_sock *tp = tcp_sk(sk);
if (rexmit == REXMIT_NONE || sk->sk_state == TCP_SYN_SENT)
return;
if (unlikely(rexmit == REXMIT_NEW)) {
__tcp_push_pending_frames(sk, tcp_current_mss(sk),
TCP_NAGLE_OFF);
if (after(tp->snd_nxt, tp->high_seq))
return;
tp->frto = 0;
}
tcp_xmit_retransmit_queue(sk);
}
static u32 tcp_newly_delivered(struct sock *sk, u32 prior_delivered, int flag)
{
const struct net *net = sock_net(sk);
struct tcp_sock *tp = tcp_sk(sk);
u32 delivered;
delivered = tp->delivered - prior_delivered;
NET_ADD_STATS(net, LINUX_MIB_TCPDELIVERED, delivered);
if (flag & FLAG_ECE)
NET_ADD_STATS(net, LINUX_MIB_TCPDELIVEREDCE, delivered);
return delivered;
}
static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
{
struct inet_connection_sock *icsk = inet_csk(sk);
struct tcp_sock *tp = tcp_sk(sk);
struct tcp_sacktag_state sack_state;
struct rate_sample rs = { .prior_delivered = 0 };
u32 prior_snd_una = tp->snd_una;
bool is_sack_reneg = tp->is_sack_reneg;
u32 ack_seq = TCP_SKB_CB(skb)->seq;
u32 ack = TCP_SKB_CB(skb)->ack_seq;
int num_dupack = 0;
int prior_packets = tp->packets_out;
u32 delivered = tp->delivered;
u32 lost = tp->lost;
int rexmit = REXMIT_NONE;
u32 prior_fack;
sack_state.first_sackt = 0;
sack_state.rate = &rs;
sack_state.sack_delivered = 0;
prefetch(sk->tcp_rtx_queue.rb_node);
if (before(ack, prior_snd_una)) {
if (before(ack, prior_snd_una - tp->max_window)) {
if (!(flag & FLAG_NO_CHALLENGE_ACK))
tcp_send_challenge_ack(sk);
return -SKB_DROP_REASON_TCP_TOO_OLD_ACK;
}
goto old_ack;
}
if (after(ack, tp->snd_nxt))
return -SKB_DROP_REASON_TCP_ACK_UNSENT_DATA;
if (after(ack, prior_snd_una)) {
flag |= FLAG_SND_UNA_ADVANCED;
icsk->icsk_retransmits = 0;
#if IS_ENABLED(CONFIG_TLS_DEVICE)
if (static_branch_unlikely(&clean_acked_data_enabled.key))
if (icsk->icsk_clean_acked)
icsk->icsk_clean_acked(sk, ack);
#endif
}
prior_fack = tcp_is_sack(tp) ? tcp_highest_sack_seq(tp) : tp->snd_una;
rs.prior_in_flight = tcp_packets_in_flight(tp);
if (flag & FLAG_UPDATE_TS_RECENT)
tcp_replace_ts_recent(tp, TCP_SKB_CB(skb)->seq);
if ((flag & (FLAG_SLOWPATH | FLAG_SND_UNA_ADVANCED)) ==
FLAG_SND_UNA_ADVANCED) {
tcp_update_wl(tp, ack_seq);
tcp_snd_una_update(tp, ack);
flag |= FLAG_WIN_UPDATE;
tcp_in_ack_event(sk, CA_ACK_WIN_UPDATE);
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPHPACKS);
} else {
u32 ack_ev_flags = CA_ACK_SLOWPATH;
if (ack_seq != TCP_SKB_CB(skb)->end_seq)
flag |= FLAG_DATA;
else
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPPUREACKS);
flag |= tcp_ack_update_window(sk, skb, ack, ack_seq);
if (TCP_SKB_CB(skb)->sacked)
flag |= tcp_sacktag_write_queue(sk, skb, prior_snd_una,
&sack_state);
if (tcp_ecn_rcv_ecn_echo(tp, tcp_hdr(skb))) {
flag |= FLAG_ECE;
ack_ev_flags |= CA_ACK_ECE;
}
if (sack_state.sack_delivered)
tcp_count_delivered(tp, sack_state.sack_delivered,
flag & FLAG_ECE);
if (flag & FLAG_WIN_UPDATE)
ack_ev_flags |= CA_ACK_WIN_UPDATE;
tcp_in_ack_event(sk, ack_ev_flags);
}
tcp_ecn_accept_cwr(sk, skb);
WRITE_ONCE(sk->sk_err_soft, 0);
icsk->icsk_probes_out = 0;
tp->rcv_tstamp = tcp_jiffies32;
if (!prior_packets)
goto no_queue;
flag |= tcp_clean_rtx_queue(sk, skb, prior_fack, prior_snd_una,
&sack_state, flag & FLAG_ECE);
tcp_rack_update_reo_wnd(sk, &rs);
if (tp->tlp_high_seq)
tcp_process_tlp_ack(sk, ack, flag);
if (tcp_ack_is_dubious(sk, flag)) {
if (!(flag & (FLAG_SND_UNA_ADVANCED |
FLAG_NOT_DUP | FLAG_DSACKING_ACK))) {
num_dupack = 1;
if (!(flag & FLAG_DATA))
num_dupack = max_t(u16, 1, skb_shinfo(skb)->gso_segs);
}
tcp_fastretrans_alert(sk, prior_snd_una, num_dupack, &flag,
&rexmit);
}
if (flag & FLAG_SET_XMIT_TIMER)
tcp_set_xmit_timer(sk);
if ((flag & FLAG_FORWARD_PROGRESS) || !(flag & FLAG_NOT_DUP))
sk_dst_confirm(sk);
delivered = tcp_newly_delivered(sk, delivered, flag);
lost = tp->lost - lost;
rs.is_ack_delayed = !!(flag & FLAG_ACK_MAYBE_DELAYED);
tcp_rate_gen(sk, delivered, lost, is_sack_reneg, sack_state.rate);
tcp_cong_control(sk, ack, delivered, flag, sack_state.rate);
tcp_xmit_recovery(sk, rexmit);
return 1;
no_queue:
if (flag & FLAG_DSACKING_ACK) {
tcp_fastretrans_alert(sk, prior_snd_una, num_dupack, &flag,
&rexmit);
tcp_newly_delivered(sk, delivered, flag);
}
tcp_ack_probe(sk);
if (tp->tlp_high_seq)
tcp_process_tlp_ack(sk, ack, flag);
return 1;
old_ack:
if (TCP_SKB_CB(skb)->sacked) {
flag |= tcp_sacktag_write_queue(sk, skb, prior_snd_una,
&sack_state);
tcp_fastretrans_alert(sk, prior_snd_una, num_dupack, &flag,
&rexmit);
tcp_newly_delivered(sk, delivered, flag);
tcp_xmit_recovery(sk, rexmit);
}
return 0;
}
static void tcp_parse_fastopen_option(int len, const unsigned char *cookie,
bool syn, struct tcp_fastopen_cookie *foc,
bool exp_opt)
{
if (!foc || !syn || len < 0 || (len & 1))
return;
if (len >= TCP_FASTOPEN_COOKIE_MIN &&
len <= TCP_FASTOPEN_COOKIE_MAX)
memcpy(foc->val, cookie, len);
else if (len != 0)
len = -1;
foc->len = len;
foc->exp = exp_opt;
}
static bool smc_parse_options(const struct tcphdr *th,
struct tcp_options_received *opt_rx,
const unsigned char *ptr,
int opsize)
{
#if IS_ENABLED(CONFIG_SMC)
if (static_branch_unlikely(&tcp_have_smc)) {
if (th->syn && !(opsize & 1) &&
opsize >= TCPOLEN_EXP_SMC_BASE &&
get_unaligned_be32(ptr) == TCPOPT_SMC_MAGIC) {
opt_rx->smc_ok = 1;
return true;
}
}
#endif
return false;
}
u16 tcp_parse_mss_option(const struct tcphdr *th, u16 user_mss)
{
const unsigned char *ptr = (const unsigned char *)(th + 1);
int length = (th->doff * 4) - sizeof(struct tcphdr);
u16 mss = 0;
while (length > 0) {
int opcode = *ptr++;
int opsize;
switch (opcode) {
case TCPOPT_EOL:
return mss;
case TCPOPT_NOP:
length--;
continue;
default:
if (length < 2)
return mss;
opsize = *ptr++;
if (opsize < 2)
return mss;
if (opsize > length)
return mss;
if (opcode == TCPOPT_MSS && opsize == TCPOLEN_MSS) {
u16 in_mss = get_unaligned_be16(ptr);
if (in_mss) {
if (user_mss && user_mss < in_mss)
in_mss = user_mss;
mss = in_mss;
}
}
ptr += opsize - 2;
length -= opsize;
}
}
return mss;
}
EXPORT_SYMBOL_GPL(tcp_parse_mss_option);
void tcp_parse_options(const struct net *net,
const struct sk_buff *skb,
struct tcp_options_received *opt_rx, int estab,
struct tcp_fastopen_cookie *foc)
{
const unsigned char *ptr;
const struct tcphdr *th = tcp_hdr(skb);
int length = (th->doff * 4) - sizeof(struct tcphdr);
ptr = (const unsigned char *)(th + 1);
opt_rx->saw_tstamp = 0;
opt_rx->saw_unknown = 0;
while (length > 0) {
int opcode = *ptr++;
int opsize;
switch (opcode) {
case TCPOPT_EOL:
return;
case TCPOPT_NOP:
length--;
continue;
default:
if (length < 2)
return;
opsize = *ptr++;
if (opsize < 2)
return;
if (opsize > length)
return;
switch (opcode) {
case TCPOPT_MSS:
if (opsize == TCPOLEN_MSS && th->syn && !estab) {
u16 in_mss = get_unaligned_be16(ptr);
if (in_mss) {
if (opt_rx->user_mss &&
opt_rx->user_mss < in_mss)
in_mss = opt_rx->user_mss;
opt_rx->mss_clamp = in_mss;
}
}
break;
case TCPOPT_WINDOW:
if (opsize == TCPOLEN_WINDOW && th->syn &&
!estab && READ_ONCE(net->ipv4.sysctl_tcp_window_scaling)) {
__u8 snd_wscale = *(__u8 *)ptr;
opt_rx->wscale_ok = 1;
if (snd_wscale > TCP_MAX_WSCALE) {
net_info_ratelimited("%s: Illegal window scaling value %d > %u received\n",
__func__,
snd_wscale,
TCP_MAX_WSCALE);
snd_wscale = TCP_MAX_WSCALE;
}
opt_rx->snd_wscale = snd_wscale;
}
break;
case TCPOPT_TIMESTAMP:
if ((opsize == TCPOLEN_TIMESTAMP) &&
((estab && opt_rx->tstamp_ok) ||
(!estab && READ_ONCE(net->ipv4.sysctl_tcp_timestamps)))) {
opt_rx->saw_tstamp = 1;
opt_rx->rcv_tsval = get_unaligned_be32(ptr);
opt_rx->rcv_tsecr = get_unaligned_be32(ptr + 4);
}
break;
case TCPOPT_SACK_PERM:
if (opsize == TCPOLEN_SACK_PERM && th->syn &&
!estab && READ_ONCE(net->ipv4.sysctl_tcp_sack)) {
opt_rx->sack_ok = TCP_SACK_SEEN;
tcp_sack_reset(opt_rx);
}
break;
case TCPOPT_SACK:
if ((opsize >= (TCPOLEN_SACK_BASE + TCPOLEN_SACK_PERBLOCK)) &&
!((opsize - TCPOLEN_SACK_BASE) % TCPOLEN_SACK_PERBLOCK) &&
opt_rx->sack_ok) {
TCP_SKB_CB(skb)->sacked = (ptr - 2) - (unsigned char *)th;
}
break;
#ifdef CONFIG_TCP_MD5SIG
case TCPOPT_MD5SIG:
break;
#endif
case TCPOPT_FASTOPEN:
tcp_parse_fastopen_option(
opsize - TCPOLEN_FASTOPEN_BASE,
ptr, th->syn, foc, false);
break;
case TCPOPT_EXP:
if (opsize >= TCPOLEN_EXP_FASTOPEN_BASE &&
get_unaligned_be16(ptr) ==
TCPOPT_FASTOPEN_MAGIC) {
tcp_parse_fastopen_option(opsize -
TCPOLEN_EXP_FASTOPEN_BASE,
ptr + 2, th->syn, foc, true);
break;
}
if (smc_parse_options(th, opt_rx, ptr, opsize))
break;
opt_rx->saw_unknown = 1;
break;
default:
opt_rx->saw_unknown = 1;
}
ptr += opsize-2;
length -= opsize;
}
}
}
EXPORT_SYMBOL(tcp_parse_options);
static bool tcp_parse_aligned_timestamp(struct tcp_sock *tp, const struct tcphdr *th)
{
const __be32 *ptr = (const __be32 *)(th + 1);
if (*ptr == htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16)
| (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP)) {
tp->rx_opt.saw_tstamp = 1;
++ptr;
tp->rx_opt.rcv_tsval = ntohl(*ptr);
++ptr;
if (*ptr)
tp->rx_opt.rcv_tsecr = ntohl(*ptr) - tp->tsoffset;
else
tp->rx_opt.rcv_tsecr = 0;
return true;
}
return false;
}
static bool tcp_fast_parse_options(const struct net *net,
const struct sk_buff *skb,
const struct tcphdr *th, struct tcp_sock *tp)
{
if (th->doff == (sizeof(*th) / 4)) {
tp->rx_opt.saw_tstamp = 0;
return false;
} else if (tp->rx_opt.tstamp_ok &&
th->doff == ((sizeof(*th) + TCPOLEN_TSTAMP_ALIGNED) / 4)) {
if (tcp_parse_aligned_timestamp(tp, th))
return true;
}
tcp_parse_options(net, skb, &tp->rx_opt, 1, NULL);
if (tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr)
tp->rx_opt.rcv_tsecr -= tp->tsoffset;
return true;
}
#ifdef CONFIG_TCP_MD5SIG
const u8 *tcp_parse_md5sig_option(const struct tcphdr *th)
{
int length = (th->doff << 2) - sizeof(*th);
const u8 *ptr = (const u8 *)(th + 1);
while (length >= TCPOLEN_MD5SIG) {
int opcode = *ptr++;
int opsize;
switch (opcode) {
case TCPOPT_EOL:
return NULL;
case TCPOPT_NOP:
length--;
continue;
default:
opsize = *ptr++;
if (opsize < 2 || opsize > length)
return NULL;
if (opcode == TCPOPT_MD5SIG)
return opsize == TCPOLEN_MD5SIG ? ptr : NULL;
}
ptr += opsize - 2;
length -= opsize;
}
return NULL;
}
EXPORT_SYMBOL(tcp_parse_md5sig_option);
#endif
static int tcp_disordered_ack(const struct sock *sk, const struct sk_buff *skb)
{
const struct tcp_sock *tp = tcp_sk(sk);
const struct tcphdr *th = tcp_hdr(skb);
u32 seq = TCP_SKB_CB(skb)->seq;
u32 ack = TCP_SKB_CB(skb)->ack_seq;
return (
(th->ack && seq == TCP_SKB_CB(skb)->end_seq && seq == tp->rcv_nxt) &&
ack == tp->snd_una &&
!tcp_may_update_window(tp, ack, seq, ntohs(th->window) << tp->rx_opt.snd_wscale) &&
(s32)(tp->rx_opt.ts_recent - tp->rx_opt.rcv_tsval) <= (inet_csk(sk)->icsk_rto * 1024) / HZ);
}
static inline bool tcp_paws_discard(const struct sock *sk,
const struct sk_buff *skb)
{
const struct tcp_sock *tp = tcp_sk(sk);
return !tcp_paws_check(&tp->rx_opt, TCP_PAWS_WINDOW) &&
!tcp_disordered_ack(sk, skb);
}
static enum skb_drop_reason tcp_sequence(const struct tcp_sock *tp,
u32 seq, u32 end_seq)
{
if (before(end_seq, tp->rcv_wup))
return SKB_DROP_REASON_TCP_OLD_SEQUENCE;
if (after(seq, tp->rcv_nxt + tcp_receive_window(tp)))
return SKB_DROP_REASON_TCP_INVALID_SEQUENCE;
return SKB_NOT_DROPPED_YET;
}
void tcp_reset(struct sock *sk, struct sk_buff *skb)
{
trace_tcp_receive_reset(sk);
if (sk_is_mptcp(sk))
mptcp_incoming_options(sk, skb);
switch (sk->sk_state) {
case TCP_SYN_SENT:
WRITE_ONCE(sk->sk_err, ECONNREFUSED);
break;
case TCP_CLOSE_WAIT:
WRITE_ONCE(sk->sk_err, EPIPE);
break;
case TCP_CLOSE:
return;
default:
WRITE_ONCE(sk->sk_err, ECONNRESET);
}
smp_wmb();
tcp_write_queue_purge(sk);
tcp_done(sk);
if (!sock_flag(sk, SOCK_DEAD))
sk_error_report(sk);
}
void tcp_fin(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);
inet_csk_schedule_ack(sk);
WRITE_ONCE(sk->sk_shutdown, sk->sk_shutdown | RCV_SHUTDOWN);
sock_set_flag(sk, SOCK_DONE);
switch (sk->sk_state) {
case TCP_SYN_RECV:
case TCP_ESTABLISHED:
tcp_set_state(sk, TCP_CLOSE_WAIT);
inet_csk_enter_pingpong_mode(sk);
break;
case TCP_CLOSE_WAIT:
case TCP_CLOSING:
break;
case TCP_LAST_ACK:
break;
case TCP_FIN_WAIT1:
tcp_send_ack(sk);
tcp_set_state(sk, TCP_CLOSING);
break;
case TCP_FIN_WAIT2:
tcp_send_ack(sk);
tcp_time_wait(sk, TCP_TIME_WAIT, 0);
break;
default:
pr_err("%s: Impossible, sk->sk_state=%d\n",
__func__, sk->sk_state);
break;
}
skb_rbtree_purge(&tp->out_of_order_queue);
if (tcp_is_sack(tp))
tcp_sack_reset(&tp->rx_opt);
if (!sock_flag(sk, SOCK_DEAD)) {
sk->sk_state_change(sk);
if (sk->sk_shutdown == SHUTDOWN_MASK ||
sk->sk_state == TCP_CLOSE)
sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP);
else
sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
}
}
static inline bool tcp_sack_extend(struct tcp_sack_block *sp, u32 seq,
u32 end_seq)
{
if (!after(seq, sp->end_seq) && !after(sp->start_seq, end_seq)) {
if (before(seq, sp->start_seq))
sp->start_seq = seq;
if (after(end_seq, sp->end_seq))
sp->end_seq = end_seq;
return true;
}
return false;
}
static void tcp_dsack_set(struct sock *sk, u32 seq, u32 end_seq)
{
struct tcp_sock *tp = tcp_sk(sk);
if (tcp_is_sack(tp) && READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_dsack)) {
int mib_idx;
if (before(seq, tp->rcv_nxt))
mib_idx = LINUX_MIB_TCPDSACKOLDSENT;
else
mib_idx = LINUX_MIB_TCPDSACKOFOSENT;
NET_INC_STATS(sock_net(sk), mib_idx);
tp->rx_opt.dsack = 1;
tp->duplicate_sack[0].start_seq = seq;
tp->duplicate_sack[0].end_seq = end_seq;
}
}
static void tcp_dsack_extend(struct sock *sk, u32 seq, u32 end_seq)
{
struct tcp_sock *tp = tcp_sk(sk);
if (!tp->rx_opt.dsack)
tcp_dsack_set(sk, seq, end_seq);
else
tcp_sack_extend(tp->duplicate_sack, seq, end_seq);
}
static void tcp_rcv_spurious_retrans(struct sock *sk, const struct sk_buff *skb)
{
if (TCP_SKB_CB(skb)->seq == tcp_sk(sk)->duplicate_sack[0].start_seq &&
sk_rethink_txhash(sk))
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPDUPLICATEDATAREHASH);
}
static void tcp_send_dupack(struct sock *sk, const struct sk_buff *skb)
{
struct tcp_sock *tp = tcp_sk(sk);
if (TCP_SKB_CB(skb)->end_seq != TCP_SKB_CB(skb)->seq &&
before(TCP_SKB_CB(skb)->seq, tp->rcv_nxt)) {
NET_INC_STATS(sock_net(sk), LINUX_MIB_DELAYEDACKLOST);
tcp_enter_quickack_mode(sk, TCP_MAX_QUICKACKS);
if (tcp_is_sack(tp) && READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_dsack)) {
u32 end_seq = TCP_SKB_CB(skb)->end_seq;
tcp_rcv_spurious_retrans(sk, skb);
if (after(TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt))
end_seq = tp->rcv_nxt;
tcp_dsack_set(sk, TCP_SKB_CB(skb)->seq, end_seq);
}
}
tcp_send_ack(sk);
}
static void tcp_sack_maybe_coalesce(struct tcp_sock *tp)
{
int this_sack;
struct tcp_sack_block *sp = &tp->selective_acks[0];
struct tcp_sack_block *swalk = sp + 1;
for (this_sack = 1; this_sack < tp->rx_opt.num_sacks;) {
if (tcp_sack_extend(sp, swalk->start_seq, swalk->end_seq)) {
int i;
tp->rx_opt.num_sacks--;
for (i = this_sack; i < tp->rx_opt.num_sacks; i++)
sp[i] = sp[i + 1];
continue;
}
this_sack++;
swalk++;
}
}
void tcp_sack_compress_send_ack(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);
if (!tp->compressed_ack)
return;
if (hrtimer_try_to_cancel(&tp->compressed_ack_timer) == 1)
__sock_put(sk);
NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPACKCOMPRESSED,
tp->compressed_ack - 1);
tp->compressed_ack = 0;
tcp_send_ack(sk);
}
#define TCP_SACK_BLOCKS_EXPECTED 2
static void tcp_sack_new_ofo_skb(struct sock *sk, u32 seq, u32 end_seq)
{
struct tcp_sock *tp = tcp_sk(sk);
struct tcp_sack_block *sp = &tp->selective_acks[0];
int cur_sacks = tp->rx_opt.num_sacks;
int this_sack;
if (!cur_sacks)
goto new_sack;
for (this_sack = 0; this_sack < cur_sacks; this_sack++, sp++) {
if (tcp_sack_extend(sp, seq, end_seq)) {
if (this_sack >= TCP_SACK_BLOCKS_EXPECTED)
tcp_sack_compress_send_ack(sk);
for (; this_sack > 0; this_sack--, sp--)
swap(*sp, *(sp - 1));
if (cur_sacks > 1)
tcp_sack_maybe_coalesce(tp);
return;
}
}
if (this_sack >= TCP_SACK_BLOCKS_EXPECTED)
tcp_sack_compress_send_ack(sk);
if (this_sack >= TCP_NUM_SACKS) {
this_sack--;
tp->rx_opt.num_sacks--;
sp--;
}
for (; this_sack > 0; this_sack--, sp--)
*sp = *(sp - 1);
new_sack:
sp->start_seq = seq;
sp->end_seq = end_seq;
tp->rx_opt.num_sacks++;
}
static void tcp_sack_remove(struct tcp_sock *tp)
{
struct tcp_sack_block *sp = &tp->selective_acks[0];
int num_sacks = tp->rx_opt.num_sacks;
int this_sack;
if (RB_EMPTY_ROOT(&tp->out_of_order_queue)) {
tp->rx_opt.num_sacks = 0;
return;
}
for (this_sack = 0; this_sack < num_sacks;) {
if (!before(tp->rcv_nxt, sp->start_seq)) {
int i;
WARN_ON(before(tp->rcv_nxt, sp->end_seq));
for (i = this_sack+1; i < num_sacks; i++)
tp->selective_acks[i-1] = tp->selective_acks[i];
num_sacks--;
continue;
}
this_sack++;
sp++;
}
tp->rx_opt.num_sacks = num_sacks;
}
static bool tcp_try_coalesce(struct sock *sk,
struct sk_buff *to,
struct sk_buff *from,
bool *fragstolen)
{
int delta;
*fragstolen = false;
if (TCP_SKB_CB(from)->seq != TCP_SKB_CB(to)->end_seq)
return false;
if (!mptcp_skb_can_collapse(to, from))
return false;
#ifdef CONFIG_TLS_DEVICE
if (from->decrypted != to->decrypted)
return false;
#endif
if (!skb_try_coalesce(to, from, fragstolen, &delta))
return false;
atomic_add(delta, &sk->sk_rmem_alloc);
sk_mem_charge(sk, delta);
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPRCVCOALESCE);
TCP_SKB_CB(to)->end_seq = TCP_SKB_CB(from)->end_seq;
TCP_SKB_CB(to)->ack_seq = TCP_SKB_CB(from)->ack_seq;
TCP_SKB_CB(to)->tcp_flags |= TCP_SKB_CB(from)->tcp_flags;
if (TCP_SKB_CB(from)->has_rxtstamp) {
TCP_SKB_CB(to)->has_rxtstamp = true;
to->tstamp = from->tstamp;
skb_hwtstamps(to)->hwtstamp = skb_hwtstamps(from)->hwtstamp;
}
return true;
}
static bool tcp_ooo_try_coalesce(struct sock *sk,
struct sk_buff *to,
struct sk_buff *from,
bool *fragstolen)
{
bool res = tcp_try_coalesce(sk, to, from, fragstolen);
if (res) {
u32 gso_segs = max_t(u16, 1, skb_shinfo(to)->gso_segs) +
max_t(u16, 1, skb_shinfo(from)->gso_segs);
skb_shinfo(to)->gso_segs = min_t(u32, gso_segs, 0xFFFF);
}
return res;
}
static void tcp_drop_reason(struct sock *sk, struct sk_buff *skb,
enum skb_drop_reason reason)
{
sk_drops_add(sk, skb);
kfree_skb_reason(skb, reason);
}
static void tcp_ofo_queue(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);
__u32 dsack_high = tp->rcv_nxt;
bool fin, fragstolen, eaten;
struct sk_buff *skb, *tail;
struct rb_node *p;
p = rb_first(&tp->out_of_order_queue);
while (p) {
skb = rb_to_skb(p);
if (after(TCP_SKB_CB(skb)->seq, tp->rcv_nxt))
break;
if (before(TCP_SKB_CB(skb)->seq, dsack_high)) {
__u32 dsack = dsack_high;
if (before(TCP_SKB_CB(skb)->end_seq, dsack_high))
dsack_high = TCP_SKB_CB(skb)->end_seq;
tcp_dsack_extend(sk, TCP_SKB_CB(skb)->seq, dsack);
}
p = rb_next(p);
rb_erase(&skb->rbnode, &tp->out_of_order_queue);
if (unlikely(!after(TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt))) {
tcp_drop_reason(sk, skb, SKB_DROP_REASON_TCP_OFO_DROP);
continue;
}
tail = skb_peek_tail(&sk->sk_receive_queue);
eaten = tail && tcp_try_coalesce(sk, tail, skb, &fragstolen);
tcp_rcv_nxt_update(tp, TCP_SKB_CB(skb)->end_seq);
fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;
if (!eaten)
__skb_queue_tail(&sk->sk_receive_queue, skb);
else
kfree_skb_partial(skb, fragstolen);
if (unlikely(fin)) {
tcp_fin(sk);
break;
}
}
}
static bool tcp_prune_ofo_queue(struct sock *sk, const struct sk_buff *in_skb);
static int tcp_prune_queue(struct sock *sk, const struct sk_buff *in_skb);
static int tcp_try_rmem_schedule(struct sock *sk, struct sk_buff *skb,
unsigned int size)
{
if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
!sk_rmem_schedule(sk, skb, size)) {
if (tcp_prune_queue(sk, skb) < 0)
return -1;
while (!sk_rmem_schedule(sk, skb, size)) {
if (!tcp_prune_ofo_queue(sk, skb))
return -1;
}
}
return 0;
}
static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)
{
struct tcp_sock *tp = tcp_sk(sk);
struct rb_node **p, *parent;
struct sk_buff *skb1;
u32 seq, end_seq;
bool fragstolen;
tcp_ecn_check_ce(sk, skb);
if (unlikely(tcp_try_rmem_schedule(sk, skb, skb->truesize))) {
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPOFODROP);
sk->sk_data_ready(sk);
tcp_drop_reason(sk, skb, SKB_DROP_REASON_PROTO_MEM);
return;
}
tp->pred_flags = 0;
inet_csk_schedule_ack(sk);
tp->rcv_ooopack += max_t(u16, 1, skb_shinfo(skb)->gso_segs);
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPOFOQUEUE);
seq = TCP_SKB_CB(skb)->seq;
end_seq = TCP_SKB_CB(skb)->end_seq;
p = &tp->out_of_order_queue.rb_node;
if (RB_EMPTY_ROOT(&tp->out_of_order_queue)) {
if (tcp_is_sack(tp)) {
tp->rx_opt.num_sacks = 1;
tp->selective_acks[0].start_seq = seq;
tp->selective_acks[0].end_seq = end_seq;
}
rb_link_node(&skb->rbnode, NULL, p);
rb_insert_color(&skb->rbnode, &tp->out_of_order_queue);
tp->ooo_last_skb = skb;
goto end;
}
if (tcp_ooo_try_coalesce(sk, tp->ooo_last_skb,
skb, &fragstolen)) {
coalesce_done:
if (tcp_is_sack(tp))
tcp_grow_window(sk, skb, true);
kfree_skb_partial(skb, fragstolen);
skb = NULL;
goto add_sack;
}
if (!before(seq, TCP_SKB_CB(tp->ooo_last_skb)->end_seq)) {
parent = &tp->ooo_last_skb->rbnode;
p = &parent->rb_right;
goto insert;
}
parent = NULL;
while (*p) {
parent = *p;
skb1 = rb_to_skb(parent);
if (before(seq, TCP_SKB_CB(skb1)->seq)) {
p = &parent->rb_left;
continue;
}
if (before(seq, TCP_SKB_CB(skb1)->end_seq)) {
if (!after(end_seq, TCP_SKB_CB(skb1)->end_seq)) {
NET_INC_STATS(sock_net(sk),
LINUX_MIB_TCPOFOMERGE);
tcp_drop_reason(sk, skb,
SKB_DROP_REASON_TCP_OFOMERGE);
skb = NULL;
tcp_dsack_set(sk, seq, end_seq);
goto add_sack;
}
if (after(seq, TCP_SKB_CB(skb1)->seq)) {
tcp_dsack_set(sk, seq, TCP_SKB_CB(skb1)->end_seq);
} else {
rb_replace_node(&skb1->rbnode, &skb->rbnode,
&tp->out_of_order_queue);
tcp_dsack_extend(sk,
TCP_SKB_CB(skb1)->seq,
TCP_SKB_CB(skb1)->end_seq);
NET_INC_STATS(sock_net(sk),
LINUX_MIB_TCPOFOMERGE);
tcp_drop_reason(sk, skb1,
SKB_DROP_REASON_TCP_OFOMERGE);
goto merge_right;
}
} else if (tcp_ooo_try_coalesce(sk, skb1,
skb, &fragstolen)) {
goto coalesce_done;
}
p = &parent->rb_right;
}
insert:
rb_link_node(&skb->rbnode, parent, p);
rb_insert_color(&skb->rbnode, &tp->out_of_order_queue);
merge_right:
while ((skb1 = skb_rb_next(skb)) != NULL) {
if (!after(end_seq, TCP_SKB_CB(skb1)->seq))
break;
if (before(end_seq, TCP_SKB_CB(skb1)->end_seq)) {
tcp_dsack_extend(sk, TCP_SKB_CB(skb1)->seq,
end_seq);
break;
}
rb_erase(&skb1->rbnode, &tp->out_of_order_queue);
tcp_dsack_extend(sk, TCP_SKB_CB(skb1)->seq,
TCP_SKB_CB(skb1)->end_seq);
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPOFOMERGE);
tcp_drop_reason(sk, skb1, SKB_DROP_REASON_TCP_OFOMERGE);
}
if (!skb1)
tp->ooo_last_skb = skb;
add_sack:
if (tcp_is_sack(tp))
tcp_sack_new_ofo_skb(sk, seq, end_seq);
end:
if (skb) {
if (tcp_is_sack(tp))
tcp_grow_window(sk, skb, false);
skb_condense(skb);
skb_set_owner_r(skb, sk);
}
}
static int __must_check tcp_queue_rcv(struct sock *sk, struct sk_buff *skb,
bool *fragstolen)
{
int eaten;
struct sk_buff *tail = skb_peek_tail(&sk->sk_receive_queue);
eaten = (tail &&
tcp_try_coalesce(sk, tail,
skb, fragstolen)) ? 1 : 0;
tcp_rcv_nxt_update(tcp_sk(sk), TCP_SKB_CB(skb)->end_seq);
if (!eaten) {
__skb_queue_tail(&sk->sk_receive_queue, skb);
skb_set_owner_r(skb, sk);
}
return eaten;
}
int tcp_send_rcvq(struct sock *sk, struct msghdr *msg, size_t size)
{
struct sk_buff *skb;
int err = -ENOMEM;
int data_len = 0;
bool fragstolen;
if (size == 0)
return 0;
if (size > PAGE_SIZE) {
int npages = min_t(size_t, size >> PAGE_SHIFT, MAX_SKB_FRAGS);
data_len = npages << PAGE_SHIFT;
size = data_len + (size & ~PAGE_MASK);
}
skb = alloc_skb_with_frags(size - data_len, data_len,
PAGE_ALLOC_COSTLY_ORDER,
&err, sk->sk_allocation);
if (!skb)
goto err;
skb_put(skb, size - data_len);
skb->data_len = data_len;
skb->len = size;
if (tcp_try_rmem_schedule(sk, skb, skb->truesize)) {
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPRCVQDROP);
goto err_free;
}
err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, size);
if (err)
goto err_free;
TCP_SKB_CB(skb)->seq = tcp_sk(sk)->rcv_nxt;
TCP_SKB_CB(skb)->end_seq = TCP_SKB_CB(skb)->seq + size;
TCP_SKB_CB(skb)->ack_seq = tcp_sk(sk)->snd_una - 1;
if (tcp_queue_rcv(sk, skb, &fragstolen)) {
WARN_ON_ONCE(fragstolen);
__kfree_skb(skb);
}
return size;
err_free:
kfree_skb(skb);
err:
return err;
}
void tcp_data_ready(struct sock *sk)
{
if (tcp_epollin_ready(sk, sk->sk_rcvlowat) || sock_flag(sk, SOCK_DONE))
sk->sk_data_ready(sk);
}
static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)
{
struct tcp_sock *tp = tcp_sk(sk);
enum skb_drop_reason reason;
bool fragstolen;
int eaten;
if (sk_is_mptcp(sk) && !mptcp_incoming_options(sk, skb)) {
__kfree_skb(skb);
return;
}
if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq) {
__kfree_skb(skb);
return;
}
skb_dst_drop(skb);
__skb_pull(skb, tcp_hdr(skb)->doff * 4);
reason = SKB_DROP_REASON_NOT_SPECIFIED;
tp->rx_opt.dsack = 0;
if (TCP_SKB_CB(skb)->seq == tp->rcv_nxt) {
if (tcp_receive_window(tp) == 0) {
reason = SKB_DROP_REASON_TCP_ZEROWINDOW;
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPZEROWINDOWDROP);
goto out_of_window;
}
queue_and_out:
if (tcp_try_rmem_schedule(sk, skb, skb->truesize)) {
inet_csk(sk)->icsk_ack.pending |=
(ICSK_ACK_NOMEM | ICSK_ACK_NOW);
inet_csk_schedule_ack(sk);
sk->sk_data_ready(sk);
if (skb_queue_len(&sk->sk_receive_queue)) {
reason = SKB_DROP_REASON_PROTO_MEM;
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPRCVQDROP);
goto drop;
}
sk_forced_mem_schedule(sk, skb->truesize);
}
eaten = tcp_queue_rcv(sk, skb, &fragstolen);
if (skb->len)
tcp_event_data_recv(sk, skb);
if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
tcp_fin(sk);
if (!RB_EMPTY_ROOT(&tp->out_of_order_queue)) {
tcp_ofo_queue(sk);
if (RB_EMPTY_ROOT(&tp->out_of_order_queue))
inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_NOW;
}
if (tp->rx_opt.num_sacks)
tcp_sack_remove(tp);
tcp_fast_path_check(sk);
if (eaten > 0)
kfree_skb_partial(skb, fragstolen);
if (!sock_flag(sk, SOCK_DEAD))
tcp_data_ready(sk);
return;
}
if (!after(TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt)) {
tcp_rcv_spurious_retrans(sk, skb);
reason = SKB_DROP_REASON_TCP_OLD_DATA;
NET_INC_STATS(sock_net(sk), LINUX_MIB_DELAYEDACKLOST);
tcp_dsack_set(sk, TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq);
out_of_window:
tcp_enter_quickack_mode(sk, TCP_MAX_QUICKACKS);
inet_csk_schedule_ack(sk);
drop:
tcp_drop_reason(sk, skb, reason);
return;
}
if (!before(TCP_SKB_CB(skb)->seq,
tp->rcv_nxt + tcp_receive_window(tp))) {
reason = SKB_DROP_REASON_TCP_OVERWINDOW;
goto out_of_window;
}
if (before(TCP_SKB_CB(skb)->seq, tp->rcv_nxt)) {
tcp_dsack_set(sk, TCP_SKB_CB(skb)->seq, tp->rcv_nxt);
if (!tcp_receive_window(tp)) {
reason = SKB_DROP_REASON_TCP_ZEROWINDOW;
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPZEROWINDOWDROP);
goto out_of_window;
}
goto queue_and_out;
}
tcp_data_queue_ofo(sk, skb);
}
static struct sk_buff *tcp_skb_next(struct sk_buff *skb, struct sk_buff_head *list)
{
if (list)
return !skb_queue_is_last(list, skb) ? skb->next : NULL;
return skb_rb_next(skb);
}
static struct sk_buff *tcp_collapse_one(struct sock *sk, struct sk_buff *skb,
struct sk_buff_head *list,
struct rb_root *root)
{
struct sk_buff *next = tcp_skb_next(skb, list);
if (list)
__skb_unlink(skb, list);
else
rb_erase(&skb->rbnode, root);
__kfree_skb(skb);
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPRCVCOLLAPSED);
return next;
}
void tcp_rbtree_insert(struct rb_root *root, struct sk_buff *skb)
{
struct rb_node **p = &root->rb_node;
struct rb_node *parent = NULL;
struct sk_buff *skb1;
while (*p) {
parent = *p;
skb1 = rb_to_skb(parent);
if (before(TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb1)->seq))
p = &parent->rb_left;
else
p = &parent->rb_right;
}
rb_link_node(&skb->rbnode, parent, p);
rb_insert_color(&skb->rbnode, root);
}
static void
tcp_collapse(struct sock *sk, struct sk_buff_head *list, struct rb_root *root,
struct sk_buff *head, struct sk_buff *tail, u32 start, u32 end)
{
struct sk_buff *skb = head, *n;
struct sk_buff_head tmp;
bool end_of_skbs;
restart:
for (end_of_skbs = true; skb != NULL && skb != tail; skb = n) {
n = tcp_skb_next(skb, list);
if (!before(start, TCP_SKB_CB(skb)->end_seq)) {
skb = tcp_collapse_one(sk, skb, list, root);
if (!skb)
break;
goto restart;
}
if (!(TCP_SKB_CB(skb)->tcp_flags & (TCPHDR_SYN | TCPHDR_FIN)) &&
(tcp_win_from_space(sk, skb->truesize) > skb->len ||
before(TCP_SKB_CB(skb)->seq, start))) {
end_of_skbs = false;
break;
}
if (n && n != tail && mptcp_skb_can_collapse(skb, n) &&
TCP_SKB_CB(skb)->end_seq != TCP_SKB_CB(n)->seq) {
end_of_skbs = false;
break;
}
start = TCP_SKB_CB(skb)->end_seq;
}
if (end_of_skbs ||
(TCP_SKB_CB(skb)->tcp_flags & (TCPHDR_SYN | TCPHDR_FIN)))
return;
__skb_queue_head_init(&tmp);
while (before(start, end)) {
int copy = min_t(int, SKB_MAX_ORDER(0, 0), end - start);
struct sk_buff *nskb;
nskb = alloc_skb(copy, GFP_ATOMIC);
if (!nskb)
break;
memcpy(nskb->cb, skb->cb, sizeof(skb->cb));
#ifdef CONFIG_TLS_DEVICE
nskb->decrypted = skb->decrypted;
#endif
TCP_SKB_CB(nskb)->seq = TCP_SKB_CB(nskb)->end_seq = start;
if (list)
__skb_queue_before(list, skb, nskb);
else
__skb_queue_tail(&tmp, nskb);
skb_set_owner_r(nskb, sk);
mptcp_skb_ext_move(nskb, skb);
while (copy > 0) {
int offset = start - TCP_SKB_CB(skb)->seq;
int size = TCP_SKB_CB(skb)->end_seq - start;
BUG_ON(offset < 0);
if (size > 0) {
size = min(copy, size);
if (skb_copy_bits(skb, offset, skb_put(nskb, size), size))
BUG();
TCP_SKB_CB(nskb)->end_seq += size;
copy -= size;
start += size;
}
if (!before(start, TCP_SKB_CB(skb)->end_seq)) {
skb = tcp_collapse_one(sk, skb, list, root);
if (!skb ||
skb == tail ||
!mptcp_skb_can_collapse(nskb, skb) ||
(TCP_SKB_CB(skb)->tcp_flags & (TCPHDR_SYN | TCPHDR_FIN)))
goto end;
#ifdef CONFIG_TLS_DEVICE
if (skb->decrypted != nskb->decrypted)
goto end;
#endif
}
}
}
end:
skb_queue_walk_safe(&tmp, skb, n)
tcp_rbtree_insert(root, skb);
}
static void tcp_collapse_ofo_queue(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);
u32 range_truesize, sum_tiny = 0;
struct sk_buff *skb, *head;
u32 start, end;
skb = skb_rb_first(&tp->out_of_order_queue);
new_range:
if (!skb) {
tp->ooo_last_skb = skb_rb_last(&tp->out_of_order_queue);
return;
}
start = TCP_SKB_CB(skb)->seq;
end = TCP_SKB_CB(skb)->end_seq;
range_truesize = skb->truesize;
for (head = skb;;) {
skb = skb_rb_next(skb);
if (!skb ||
after(TCP_SKB_CB(skb)->seq, end) ||
before(TCP_SKB_CB(skb)->end_seq, start)) {
if (range_truesize != head->truesize ||
end - start >= SKB_WITH_OVERHEAD(PAGE_SIZE)) {
tcp_collapse(sk, NULL, &tp->out_of_order_queue,
head, skb, start, end);
} else {
sum_tiny += range_truesize;
if (sum_tiny > sk->sk_rcvbuf >> 3)
return;
}
goto new_range;
}
range_truesize += skb->truesize;
if (unlikely(before(TCP_SKB_CB(skb)->seq, start)))
start = TCP_SKB_CB(skb)->seq;
if (after(TCP_SKB_CB(skb)->end_seq, end))
end = TCP_SKB_CB(skb)->end_seq;
}
}
static bool tcp_prune_ofo_queue(struct sock *sk, const struct sk_buff *in_skb)
{
struct tcp_sock *tp = tcp_sk(sk);
struct rb_node *node, *prev;
bool pruned = false;
int goal;
if (RB_EMPTY_ROOT(&tp->out_of_order_queue))
return false;
goal = sk->sk_rcvbuf >> 3;
node = &tp->ooo_last_skb->rbnode;
do {
struct sk_buff *skb = rb_to_skb(node);
if (after(TCP_SKB_CB(in_skb)->seq, TCP_SKB_CB(skb)->seq))
break;
pruned = true;
prev = rb_prev(node);
rb_erase(node, &tp->out_of_order_queue);
goal -= skb->truesize;
tcp_drop_reason(sk, skb, SKB_DROP_REASON_TCP_OFO_QUEUE_PRUNE);
tp->ooo_last_skb = rb_to_skb(prev);
if (!prev || goal <= 0) {
if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
!tcp_under_memory_pressure(sk))
break;
goal = sk->sk_rcvbuf >> 3;
}
node = prev;
} while (node);
if (pruned) {
NET_INC_STATS(sock_net(sk), LINUX_MIB_OFOPRUNED);
if (tp->rx_opt.sack_ok)
tcp_sack_reset(&tp->rx_opt);
}
return pruned;
}
static int tcp_prune_queue(struct sock *sk, const struct sk_buff *in_skb)
{
struct tcp_sock *tp = tcp_sk(sk);
NET_INC_STATS(sock_net(sk), LINUX_MIB_PRUNECALLED);
if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
tcp_clamp_window(sk);
else if (tcp_under_memory_pressure(sk))
tcp_adjust_rcv_ssthresh(sk);
if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf)
return 0;
tcp_collapse_ofo_queue(sk);
if (!skb_queue_empty(&sk->sk_receive_queue))
tcp_collapse(sk, &sk->sk_receive_queue, NULL,
skb_peek(&sk->sk_receive_queue),
NULL,
tp->copied_seq, tp->rcv_nxt);
if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf)
return 0;
tcp_prune_ofo_queue(sk, in_skb);
if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf)
return 0;
NET_INC_STATS(sock_net(sk), LINUX_MIB_RCVPRUNED);
tp->pred_flags = 0;
return -1;
}
static bool tcp_should_expand_sndbuf(struct sock *sk)
{
const struct tcp_sock *tp = tcp_sk(sk);
if (sk->sk_userlocks & SOCK_SNDBUF_LOCK)
return false;
if (tcp_under_memory_pressure(sk)) {
int unused_mem = sk_unused_reserved_mem(sk);
if (unused_mem > SOCK_MIN_SNDBUF)
WRITE_ONCE(sk->sk_sndbuf, unused_mem);
return false;
}
if (sk_memory_allocated(sk) >= sk_prot_mem_limits(sk, 0))
return false;
if (tcp_packets_in_flight(tp) >= tcp_snd_cwnd(tp))
return false;
return true;
}
static void tcp_new_space(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);
if (tcp_should_expand_sndbuf(sk)) {
tcp_sndbuf_expand(sk);
tp->snd_cwnd_stamp = tcp_jiffies32;
}
INDIRECT_CALL_1(sk->sk_write_space, sk_stream_write_space, sk);
}
void tcp_check_space(struct sock *sk)
{
smp_mb();
if (sk->sk_socket &&
test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
tcp_new_space(sk);
if (!test_bit(SOCK_NOSPACE, &sk->sk_socket->flags))
tcp_chrono_stop(sk, TCP_CHRONO_SNDBUF_LIMITED);
}
}
static inline void tcp_data_snd_check(struct sock *sk)
{
tcp_push_pending_frames(sk);
tcp_check_space(sk);
}
static void __tcp_ack_snd_check(struct sock *sk, int ofo_possible)
{
struct tcp_sock *tp = tcp_sk(sk);
unsigned long rtt, delay;
if (((tp->rcv_nxt - tp->rcv_wup) > inet_csk(sk)->icsk_ack.rcv_mss &&
(tp->rcv_nxt - tp->copied_seq < sk->sk_rcvlowat ||
__tcp_select_window(sk) >= tp->rcv_wnd)) ||
tcp_in_quickack_mode(sk) ||
inet_csk(sk)->icsk_ack.pending & ICSK_ACK_NOW) {
send_now:
tcp_send_ack(sk);
return;
}
if (!ofo_possible || RB_EMPTY_ROOT(&tp->out_of_order_queue)) {
tcp_send_delayed_ack(sk);
return;
}
if (!tcp_is_sack(tp) ||
tp->compressed_ack >= READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_comp_sack_nr))
goto send_now;
if (tp->compressed_ack_rcv_nxt != tp->rcv_nxt) {
tp->compressed_ack_rcv_nxt = tp->rcv_nxt;
tp->dup_ack_counter = 0;
}
if (tp->dup_ack_counter < TCP_FASTRETRANS_THRESH) {
tp->dup_ack_counter++;
goto send_now;
}
tp->compressed_ack++;
if (hrtimer_is_queued(&tp->compressed_ack_timer))
return;
rtt = tp->rcv_rtt_est.rtt_us;
if (tp->srtt_us && tp->srtt_us < rtt)
rtt = tp->srtt_us;
delay = min_t(unsigned long,
READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_comp_sack_delay_ns),
rtt * (NSEC_PER_USEC >> 3)/20);
sock_hold(sk);
hrtimer_start_range_ns(&tp->compressed_ack_timer, ns_to_ktime(delay),
READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_comp_sack_slack_ns),
HRTIMER_MODE_REL_PINNED_SOFT);
}
static inline void tcp_ack_snd_check(struct sock *sk)
{
if (!inet_csk_ack_scheduled(sk)) {
return;
}
__tcp_ack_snd_check(sk, 1);
}
static void tcp_check_urg(struct sock *sk, const struct tcphdr *th)
{
struct tcp_sock *tp = tcp_sk(sk);
u32 ptr = ntohs(th->urg_ptr);
if (ptr && !READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_stdurg))
ptr--;
ptr += ntohl(th->seq);
if (after(tp->copied_seq, ptr))
return;
if (before(ptr, tp->rcv_nxt))
return;
if (tp->urg_data && !after(ptr, tp->urg_seq))
return;
sk_send_sigurg(sk);
if (tp->urg_seq == tp->copied_seq && tp->urg_data &&
!sock_flag(sk, SOCK_URGINLINE) && tp->copied_seq != tp->rcv_nxt) {
struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
tp->copied_seq++;
if (skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq)) {
__skb_unlink(skb, &sk->sk_receive_queue);
__kfree_skb(skb);
}
}
WRITE_ONCE(tp->urg_data, TCP_URG_NOTYET);
WRITE_ONCE(tp->urg_seq, ptr);
tp->pred_flags = 0;
}
static void tcp_urg(struct sock *sk, struct sk_buff *skb, const struct tcphdr *th)
{
struct tcp_sock *tp = tcp_sk(sk);
if (unlikely(th->urg))
tcp_check_urg(sk, th);
if (unlikely(tp->urg_data == TCP_URG_NOTYET)) {
u32 ptr = tp->urg_seq - ntohl(th->seq) + (th->doff * 4) -
th->syn;
if (ptr < skb->len) {
u8 tmp;
if (skb_copy_bits(skb, ptr, &tmp, 1))
BUG();
WRITE_ONCE(tp->urg_data, TCP_URG_VALID | tmp);
if (!sock_flag(sk, SOCK_DEAD))
sk->sk_data_ready(sk);
}
}
}
static bool tcp_reset_check(const struct sock *sk, const struct sk_buff *skb)
{
const struct tcp_sock *tp = tcp_sk(sk);
return unlikely(TCP_SKB_CB(skb)->seq == (tp->rcv_nxt - 1) &&
(1 << sk->sk_state) & (TCPF_CLOSE_WAIT | TCPF_LAST_ACK |
TCPF_CLOSING));
}
static bool tcp_validate_incoming(struct sock *sk, struct sk_buff *skb,
const struct tcphdr *th, int syn_inerr)
{
struct tcp_sock *tp = tcp_sk(sk);
SKB_DR(reason);
if (tcp_fast_parse_options(sock_net(sk), skb, th, tp) &&
tp->rx_opt.saw_tstamp &&
tcp_paws_discard(sk, skb)) {
if (!th->rst) {
if (unlikely(th->syn))
goto syn_challenge;
NET_INC_STATS(sock_net(sk), LINUX_MIB_PAWSESTABREJECTED);
if (!tcp_oow_rate_limited(sock_net(sk), skb,
LINUX_MIB_TCPACKSKIPPEDPAWS,
&tp->last_oow_ack_time))
tcp_send_dupack(sk, skb);
SKB_DR_SET(reason, TCP_RFC7323_PAWS);
goto discard;
}
}
reason = tcp_sequence(tp, TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq);
if (reason) {
if (!th->rst) {
if (th->syn)
goto syn_challenge;
if (!tcp_oow_rate_limited(sock_net(sk), skb,
LINUX_MIB_TCPACKSKIPPEDSEQ,
&tp->last_oow_ack_time))
tcp_send_dupack(sk, skb);
} else if (tcp_reset_check(sk, skb)) {
goto reset;
}
goto discard;
}
if (th->rst) {
if (TCP_SKB_CB(skb)->seq == tp->rcv_nxt ||
tcp_reset_check(sk, skb))
goto reset;
if (tcp_is_sack(tp) && tp->rx_opt.num_sacks > 0) {
struct tcp_sack_block *sp = &tp->selective_acks[0];
int max_sack = sp[0].end_seq;
int this_sack;
for (this_sack = 1; this_sack < tp->rx_opt.num_sacks;
++this_sack) {
max_sack = after(sp[this_sack].end_seq,
max_sack) ?
sp[this_sack].end_seq : max_sack;
}
if (TCP_SKB_CB(skb)->seq == max_sack)
goto reset;
}
if (tp->syn_fastopen && !tp->data_segs_in &&
sk->sk_state == TCP_ESTABLISHED)
tcp_fastopen_active_disable(sk);
tcp_send_challenge_ack(sk);
SKB_DR_SET(reason, TCP_RESET);
goto discard;
}
if (th->syn) {
syn_challenge:
if (syn_inerr)
TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPSYNCHALLENGE);
tcp_send_challenge_ack(sk);
SKB_DR_SET(reason, TCP_INVALID_SYN);
goto discard;
}
bpf_skops_parse_hdr(sk, skb);
return true;
discard:
tcp_drop_reason(sk, skb, reason);
return false;
reset:
tcp_reset(sk, skb);
__kfree_skb(skb);
return false;
}
void tcp_rcv_established(struct sock *sk, struct sk_buff *skb)
{
enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED;
const struct tcphdr *th = (const struct tcphdr *)skb->data;
struct tcp_sock *tp = tcp_sk(sk);
unsigned int len = skb->len;
trace_tcp_probe(sk, skb);
tcp_mstamp_refresh(tp);
if (unlikely(!rcu_access_pointer(sk->sk_rx_dst)))
inet_csk(sk)->icsk_af_ops->sk_rx_dst_set(sk, skb);
tp->rx_opt.saw_tstamp = 0;
if ((tcp_flag_word(th) & TCP_HP_BITS) == tp->pred_flags &&
TCP_SKB_CB(skb)->seq == tp->rcv_nxt &&
!after(TCP_SKB_CB(skb)->ack_seq, tp->snd_nxt)) {
int tcp_header_len = tp->tcp_header_len;
if (tcp_header_len == sizeof(struct tcphdr) + TCPOLEN_TSTAMP_ALIGNED) {
if (!tcp_parse_aligned_timestamp(tp, th))
goto slow_path;
if ((s32)(tp->rx_opt.rcv_tsval - tp->rx_opt.ts_recent) < 0)
goto slow_path;
}
if (len <= tcp_header_len) {
if (len == tcp_header_len) {
if (tcp_header_len ==
(sizeof(struct tcphdr) + TCPOLEN_TSTAMP_ALIGNED) &&
tp->rcv_nxt == tp->rcv_wup)
tcp_store_ts_recent(tp);
tcp_ack(sk, skb, 0);
__kfree_skb(skb);
tcp_data_snd_check(sk);
tp->rcv_rtt_last_tsecr = tp->rx_opt.rcv_tsecr;
return;
} else {
reason = SKB_DROP_REASON_PKT_TOO_SMALL;
TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
goto discard;
}
} else {
int eaten = 0;
bool fragstolen = false;
if (tcp_checksum_complete(skb))
goto csum_error;
if ((int)skb->truesize > sk->sk_forward_alloc)
goto step5;
if (tcp_header_len ==
(sizeof(struct tcphdr) + TCPOLEN_TSTAMP_ALIGNED) &&
tp->rcv_nxt == tp->rcv_wup)
tcp_store_ts_recent(tp);
tcp_rcv_rtt_measure_ts(sk, skb);
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPHPHITS);
skb_dst_drop(skb);
__skb_pull(skb, tcp_header_len);
eaten = tcp_queue_rcv(sk, skb, &fragstolen);
tcp_event_data_recv(sk, skb);
if (TCP_SKB_CB(skb)->ack_seq != tp->snd_una) {
tcp_ack(sk, skb, FLAG_DATA);
tcp_data_snd_check(sk);
if (!inet_csk_ack_scheduled(sk))
goto no_ack;
} else {
tcp_update_wl(tp, TCP_SKB_CB(skb)->seq);
}
__tcp_ack_snd_check(sk, 0);
no_ack:
if (eaten)
kfree_skb_partial(skb, fragstolen);
tcp_data_ready(sk);
return;
}
}
slow_path:
if (len < (th->doff << 2) || tcp_checksum_complete(skb))
goto csum_error;
if (!th->ack && !th->rst && !th->syn) {
reason = SKB_DROP_REASON_TCP_FLAGS;
goto discard;
}
if (!tcp_validate_incoming(sk, skb, th, 1))
return;
step5:
reason = tcp_ack(sk, skb, FLAG_SLOWPATH | FLAG_UPDATE_TS_RECENT);
if ((int)reason < 0) {
reason = -reason;
goto discard;
}
tcp_rcv_rtt_measure_ts(sk, skb);
tcp_urg(sk, skb, th);
tcp_data_queue(sk, skb);
tcp_data_snd_check(sk);
tcp_ack_snd_check(sk);
return;
csum_error:
reason = SKB_DROP_REASON_TCP_CSUM;
trace_tcp_bad_csum(skb);
TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
discard:
tcp_drop_reason(sk, skb, reason);
}
EXPORT_SYMBOL(tcp_rcv_established);
void tcp_init_transfer(struct sock *sk, int bpf_op, struct sk_buff *skb)
{
struct inet_connection_sock *icsk = inet_csk(sk);
struct tcp_sock *tp = tcp_sk(sk);
tcp_mtup_init(sk);
icsk->icsk_af_ops->rebuild_header(sk);
tcp_init_metrics(sk);
if (tp->total_retrans > 1 && tp->undo_marker)
tcp_snd_cwnd_set(tp, 1);
else
tcp_snd_cwnd_set(tp, tcp_init_cwnd(tp, __sk_dst_get(sk)));
tp->snd_cwnd_stamp = tcp_jiffies32;
bpf_skops_established(sk, bpf_op, skb);
if (!icsk->icsk_ca_initialized)
tcp_init_congestion_control(sk);
tcp_init_buffer_space(sk);
}
void tcp_finish_connect(struct sock *sk, struct sk_buff *skb)
{
struct tcp_sock *tp = tcp_sk(sk);
struct inet_connection_sock *icsk = inet_csk(sk);
tcp_set_state(sk, TCP_ESTABLISHED);
icsk->icsk_ack.lrcvtime = tcp_jiffies32;
if (skb) {
icsk->icsk_af_ops->sk_rx_dst_set(sk, skb);
security_inet_conn_established(sk, skb);
sk_mark_napi_id(sk, skb);
}
tcp_init_transfer(sk, BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB, skb);
tp->lsndtime = tcp_jiffies32;
if (sock_flag(sk, SOCK_KEEPOPEN))
inet_csk_reset_keepalive_timer(sk, keepalive_time_when(tp));
if (!tp->rx_opt.snd_wscale)
__tcp_fast_path_on(tp, tp->snd_wnd);
else
tp->pred_flags = 0;
}
static bool tcp_rcv_fastopen_synack(struct sock *sk, struct sk_buff *synack,
struct tcp_fastopen_cookie *cookie)
{
struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *data = tp->syn_data ? tcp_rtx_queue_head(sk) : NULL;
u16 mss = tp->rx_opt.mss_clamp, try_exp = 0;
bool syn_drop = false;
if (mss == tp->rx_opt.user_mss) {
struct tcp_options_received opt;
tcp_clear_options(&opt);
opt.user_mss = opt.mss_clamp = 0;
tcp_parse_options(sock_net(sk), synack, &opt, 0, NULL);
mss = opt.mss_clamp;
}
if (!tp->syn_fastopen) {
cookie->len = -1;
} else if (tp->total_retrans) {
syn_drop = (cookie->len < 0 && data);
} else if (cookie->len < 0 && !tp->syn_data) {
try_exp = tp->syn_fastopen_exp ? 2 : 1;
}
tcp_fastopen_cache_set(sk, mss, cookie, syn_drop, try_exp);
if (data) {
if (tp->total_retrans)
tp->fastopen_client_fail = TFO_SYN_RETRANSMITTED;
else
tp->fastopen_client_fail = TFO_DATA_NOT_ACKED;
skb_rbtree_walk_from(data)
tcp_mark_skb_lost(sk, data);
tcp_xmit_retransmit_queue(sk);
NET_INC_STATS(sock_net(sk),
LINUX_MIB_TCPFASTOPENACTIVEFAIL);
return true;
}
tp->syn_data_acked = tp->syn_data;
if (tp->syn_data_acked) {
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPFASTOPENACTIVE);
if (tp->delivered > 1)
--tp->delivered;
}
tcp_fastopen_add_skb(sk, synack);
return false;
}
static void smc_check_reset_syn(struct tcp_sock *tp)
{
#if IS_ENABLED(CONFIG_SMC)
if (static_branch_unlikely(&tcp_have_smc)) {
if (tp->syn_smc && !tp->rx_opt.smc_ok)
tp->syn_smc = 0;
}
#endif
}
static void tcp_try_undo_spurious_syn(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);
u32 syn_stamp;
syn_stamp = tp->retrans_stamp;
if (tp->undo_marker && syn_stamp && tp->rx_opt.saw_tstamp &&
syn_stamp == tp->rx_opt.rcv_tsecr)
tp->undo_marker = 0;
}
static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
const struct tcphdr *th)
{
struct inet_connection_sock *icsk = inet_csk(sk);
struct tcp_sock *tp = tcp_sk(sk);
struct tcp_fastopen_cookie foc = { .len = -1 };
int saved_clamp = tp->rx_opt.mss_clamp;
bool fastopen_fail;
SKB_DR(reason);
tcp_parse_options(sock_net(sk), skb, &tp->rx_opt, 0, &foc);
if (tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr)
tp->rx_opt.rcv_tsecr -= tp->tsoffset;
if (th->ack) {
if (!after(TCP_SKB_CB(skb)->ack_seq, tp->snd_una) ||
after(TCP_SKB_CB(skb)->ack_seq, tp->snd_nxt)) {
if (icsk->icsk_retransmits == 0)
inet_csk_reset_xmit_timer(sk,
ICSK_TIME_RETRANS,
TCP_TIMEOUT_MIN, TCP_RTO_MAX);
goto reset_and_undo;
}
if (tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr &&
!between(tp->rx_opt.rcv_tsecr, tp->retrans_stamp,
tcp_time_stamp(tp))) {
NET_INC_STATS(sock_net(sk),
LINUX_MIB_PAWSACTIVEREJECTED);
goto reset_and_undo;
}
if (th->rst) {
tcp_reset(sk, skb);
consume:
__kfree_skb(skb);
return 0;
}
if (!th->syn) {
SKB_DR_SET(reason, TCP_FLAGS);
goto discard_and_undo;
}
tcp_ecn_rcv_synack(tp, th);
tcp_init_wl(tp, TCP_SKB_CB(skb)->seq);
tcp_try_undo_spurious_syn(sk);
tcp_ack(sk, skb, FLAG_SLOWPATH);
WRITE_ONCE(tp->rcv_nxt, TCP_SKB_CB(skb)->seq + 1);
tp->rcv_wup = TCP_SKB_CB(skb)->seq + 1;
tp->snd_wnd = ntohs(th->window);
if (!tp->rx_opt.wscale_ok) {
tp->rx_opt.snd_wscale = tp->rx_opt.rcv_wscale = 0;
tp->window_clamp = min(tp->window_clamp, 65535U);
}
if (tp->rx_opt.saw_tstamp) {
tp->rx_opt.tstamp_ok = 1;
tp->tcp_header_len =
sizeof(struct tcphdr) + TCPOLEN_TSTAMP_ALIGNED;
tp->advmss -= TCPOLEN_TSTAMP_ALIGNED;
tcp_store_ts_recent(tp);
} else {
tp->tcp_header_len = sizeof(struct tcphdr);
}
tcp_sync_mss(sk, icsk->icsk_pmtu_cookie);
tcp_initialize_rcv_mss(sk);
WRITE_ONCE(tp->copied_seq, tp->rcv_nxt);
smc_check_reset_syn(tp);
smp_mb();
tcp_finish_connect(sk, skb);
fastopen_fail = (tp->syn_fastopen || tp->syn_data) &&
tcp_rcv_fastopen_synack(sk, skb, &foc);
if (!sock_flag(sk, SOCK_DEAD)) {
sk->sk_state_change(sk);
sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT);
}
if (fastopen_fail)
return -1;
if (sk->sk_write_pending ||
READ_ONCE(icsk->icsk_accept_queue.rskq_defer_accept) ||
inet_csk_in_pingpong_mode(sk)) {
inet_csk_schedule_ack(sk);
tcp_enter_quickack_mode(sk, TCP_MAX_QUICKACKS);
inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
TCP_DELACK_MAX, TCP_RTO_MAX);
goto consume;
}
tcp_send_ack(sk);
return -1;
}
if (th->rst) {
SKB_DR_SET(reason, TCP_RESET);
goto discard_and_undo;
}
if (tp->rx_opt.ts_recent_stamp && tp->rx_opt.saw_tstamp &&
tcp_paws_reject(&tp->rx_opt, 0)) {
SKB_DR_SET(reason, TCP_RFC7323_PAWS);
goto discard_and_undo;
}
if (th->syn) {
tcp_set_state(sk, TCP_SYN_RECV);
if (tp->rx_opt.saw_tstamp) {
tp->rx_opt.tstamp_ok = 1;
tcp_store_ts_recent(tp);
tp->tcp_header_len =
sizeof(struct tcphdr) + TCPOLEN_TSTAMP_ALIGNED;
} else {
tp->tcp_header_len = sizeof(struct tcphdr);
}
WRITE_ONCE(tp->rcv_nxt, TCP_SKB_CB(skb)->seq + 1);
WRITE_ONCE(tp->copied_seq, tp->rcv_nxt);
tp->rcv_wup = TCP_SKB_CB(skb)->seq + 1;
tp->snd_wnd = ntohs(th->window);
tp->snd_wl1 = TCP_SKB_CB(skb)->seq;
tp->max_window = tp->snd_wnd;
tcp_ecn_rcv_syn(tp, th);
tcp_mtup_init(sk);
tcp_sync_mss(sk, icsk->icsk_pmtu_cookie);
tcp_initialize_rcv_mss(sk);
tcp_send_synack(sk);
#if 0
return -1;
#else
goto consume;
#endif
}
discard_and_undo:
tcp_clear_options(&tp->rx_opt);
tp->rx_opt.mss_clamp = saved_clamp;
tcp_drop_reason(sk, skb, reason);
return 0;
reset_and_undo:
tcp_clear_options(&tp->rx_opt);
tp->rx_opt.mss_clamp = saved_clamp;
return 1;
}
static void tcp_rcv_synrecv_state_fastopen(struct sock *sk)
{
struct request_sock *req;
if (inet_csk(sk)->icsk_ca_state == TCP_CA_Loss)
tcp_try_undo_loss(sk, false);
tcp_sk(sk)->retrans_stamp = 0;
inet_csk(sk)->icsk_retransmits = 0;
req = rcu_dereference_protected(tcp_sk(sk)->fastopen_rsk,
lockdep_sock_is_held(sk));
reqsk_fastopen_remove(sk, req, false);
tcp_rearm_rto(sk);
}
int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
{
struct tcp_sock *tp = tcp_sk(sk);
struct inet_connection_sock *icsk = inet_csk(sk);
const struct tcphdr *th = tcp_hdr(skb);
struct request_sock *req;
int queued = 0;
bool acceptable;
SKB_DR(reason);
switch (sk->sk_state) {
case TCP_CLOSE:
SKB_DR_SET(reason, TCP_CLOSE);
goto discard;
case TCP_LISTEN:
if (th->ack)
return 1;
if (th->rst) {
SKB_DR_SET(reason, TCP_RESET);
goto discard;
}
if (th->syn) {
if (th->fin) {
SKB_DR_SET(reason, TCP_FLAGS);
goto discard;
}
rcu_read_lock();
local_bh_disable();
acceptable = icsk->icsk_af_ops->conn_request(sk, skb) >= 0;
local_bh_enable();
rcu_read_unlock();
if (!acceptable)
return 1;
consume_skb(skb);
return 0;
}
SKB_DR_SET(reason, TCP_FLAGS);
goto discard;
case TCP_SYN_SENT:
tp->rx_opt.saw_tstamp = 0;
tcp_mstamp_refresh(tp);
queued = tcp_rcv_synsent_state_process(sk, skb, th);
if (queued >= 0)
return queued;
tcp_urg(sk, skb, th);
__kfree_skb(skb);
tcp_data_snd_check(sk);
return 0;
}
tcp_mstamp_refresh(tp);
tp->rx_opt.saw_tstamp = 0;
req = rcu_dereference_protected(tp->fastopen_rsk,
lockdep_sock_is_held(sk));
if (req) {
bool req_stolen;
WARN_ON_ONCE(sk->sk_state != TCP_SYN_RECV &&
sk->sk_state != TCP_FIN_WAIT1);
if (!tcp_check_req(sk, skb, req, true, &req_stolen)) {
SKB_DR_SET(reason, TCP_FASTOPEN);
goto discard;
}
}
if (!th->ack && !th->rst && !th->syn) {
SKB_DR_SET(reason, TCP_FLAGS);
goto discard;
}
if (!tcp_validate_incoming(sk, skb, th, 0))
return 0;
acceptable = tcp_ack(sk, skb, FLAG_SLOWPATH |
FLAG_UPDATE_TS_RECENT |
FLAG_NO_CHALLENGE_ACK) > 0;
if (!acceptable) {
if (sk->sk_state == TCP_SYN_RECV)
return 1;
tcp_send_challenge_ack(sk);
SKB_DR_SET(reason, TCP_OLD_ACK);
goto discard;
}
switch (sk->sk_state) {
case TCP_SYN_RECV:
tp->delivered++;
if (!tp->srtt_us)
tcp_synack_rtt_meas(sk, req);
if (req) {
tcp_rcv_synrecv_state_fastopen(sk);
} else {
tcp_try_undo_spurious_syn(sk);
tp->retrans_stamp = 0;
tcp_init_transfer(sk, BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB,
skb);
WRITE_ONCE(tp->copied_seq, tp->rcv_nxt);
}
smp_mb();
tcp_set_state(sk, TCP_ESTABLISHED);
sk->sk_state_change(sk);
if (sk->sk_socket)
sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT);
tp->snd_una = TCP_SKB_CB(skb)->ack_seq;
tp->snd_wnd = ntohs(th->window) << tp->rx_opt.snd_wscale;
tcp_init_wl(tp, TCP_SKB_CB(skb)->seq);
if (tp->rx_opt.tstamp_ok)
tp->advmss -= TCPOLEN_TSTAMP_ALIGNED;
if (!inet_csk(sk)->icsk_ca_ops->cong_control)
tcp_update_pacing_rate(sk);
tp->lsndtime = tcp_jiffies32;
tcp_initialize_rcv_mss(sk);
tcp_fast_path_on(tp);
break;
case TCP_FIN_WAIT1: {
int tmo;
if (req)
tcp_rcv_synrecv_state_fastopen(sk);
if (tp->snd_una != tp->write_seq)
break;
tcp_set_state(sk, TCP_FIN_WAIT2);
WRITE_ONCE(sk->sk_shutdown, sk->sk_shutdown | SEND_SHUTDOWN);
sk_dst_confirm(sk);
if (!sock_flag(sk, SOCK_DEAD)) {
sk->sk_state_change(sk);
break;
}