/* SPDX-License-Identifier: GPL-2.0
*
* Copyright (c) 2019 Facebook
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*
* Include file for sample Host Bandwidth Manager (HBM) BPF programs
*/
#define KBUILD_MODNAME "foo"
#include <uapi/linux/bpf.h>
#include <uapi/linux/if_ether.h>
#include <uapi/linux/if_packet.h>
#include <uapi/linux/ip.h>
#include <uapi/linux/ipv6.h>
#include <uapi/linux/in.h>
#include <uapi/linux/tcp.h>
#include <uapi/linux/filter.h>
#include <uapi/linux/pkt_cls.h>
#include <net/ipv6.h>
#include <net/inet_ecn.h>
#include <bpf/bpf_endian.h>
#include <bpf/bpf_helpers.h>
#include "hbm.h"
#define DROP_PKT 0
#define ALLOW_PKT 1
#define TCP_ECN_OK 1
#define CWR 2
#ifndef HBM_DEBUG // Define HBM_DEBUG to enable debugging
#undef bpf_printk
#define bpf_printk(fmt, ...)
#endif
#define INITIAL_CREDIT_PACKETS 100
#define MAX_BYTES_PER_PACKET 1500
#define MARK_THRESH (40 * MAX_BYTES_PER_PACKET)
#define DROP_THRESH (80 * 5 * MAX_BYTES_PER_PACKET)
#define LARGE_PKT_DROP_THRESH (DROP_THRESH - (15 * MAX_BYTES_PER_PACKET))
#define MARK_REGION_SIZE (LARGE_PKT_DROP_THRESH - MARK_THRESH)
#define LARGE_PKT_THRESH 120
#define MAX_CREDIT (100 * MAX_BYTES_PER_PACKET)
#define INIT_CREDIT (INITIAL_CREDIT_PACKETS * MAX_BYTES_PER_PACKET)
// Time base accounting for fq's EDT
#define BURST_SIZE_NS 100000 // 100us
#define MARK_THRESH_NS 50000 // 50us
#define DROP_THRESH_NS 500000 // 500us
// Reserve 20us of queuing for small packets (less than 120 bytes)
#define LARGE_PKT_DROP_THRESH_NS (DROP_THRESH_NS - 20000)
#define MARK_REGION_SIZE_NS (LARGE_PKT_DROP_THRESH_NS - MARK_THRESH_NS)
// rate in bytes per ns << 20
#define CREDIT_PER_NS(delta, rate) ((((u64)(delta)) * (rate)) >> 20)
#define BYTES_PER_NS(delta, rate) ((((u64)(delta)) * (rate)) >> 20)
#define BYTES_TO_NS(bytes, rate) div64_u64(((u64)(bytes)) << 20, (u64)(rate))
struct {
__uint(type, BPF_MAP_TYPE_CGROUP_STORAGE);
__type(key, struct bpf_cgroup_storage_key);
__type(value, struct hbm_vqueue);
} queue_state SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__uint(max_entries, 1);
__type(key, u32);
__type(value, struct hbm_queue_stats);
} queue_stats SEC(".maps");
struct hbm_pkt_info {
int cwnd;
int rtt;
int packets_out;
bool is_ip;
bool is_tcp;
short ecn;
};
static int get_tcp_info(struct __sk_buff *skb, struct hbm_pkt_info *pkti)
{
struct bpf_sock *sk;
struct bpf_tcp_sock *tp;
sk = skb->sk;
if (sk) {
sk = bpf_sk_fullsock(sk);
if (sk) {
if (sk->protocol == IPPROTO_TCP) {
tp = bpf_tcp_sock(sk);
if (tp) {
pkti->cwnd = tp->snd_cwnd;
pkti->rtt = tp->srtt_us >> 3;
pkti->packets_out = tp->packets_out;
return 0;
}
}
}
}
pkti->cwnd = 0;
pkti->rtt = 0;
pkti->packets_out = 0;
return 1;
}
static void hbm_get_pkt_info(struct __sk_buff *skb,
struct hbm_pkt_info *pkti)
{
struct iphdr iph;
struct ipv6hdr *ip6h;
pkti->cwnd = 0;
pkti->rtt = 0;
bpf_skb_load_bytes(skb, 0, &iph, 12);
if (iph.version == 6) {
ip6h = (struct ipv6hdr *)&iph;
pkti->is_ip = true;
pkti->is_tcp = (ip6h->nexthdr == 6);
pkti->ecn = (ip6h->flow_lbl[0] >> 4) & INET_ECN_MASK;
} else if (iph.version == 4) {
pkti->is_ip = true;
pkti->is_tcp = (iph.protocol == 6);
pkti->ecn = iph.tos & INET_ECN_MASK;
} else {
pkti->is_ip = false;
pkti->is_tcp = false;
pkti->ecn = 0;
}
if (pkti->is_tcp)
get_tcp_info(skb, pkti);
}
static __always_inline void hbm_init_vqueue(struct hbm_vqueue *qdp, int rate)
{
bpf_printk("Initializing queue_state, rate:%d\n", rate * 128);
qdp->lasttime = bpf_ktime_get_ns();
qdp->credit = INIT_CREDIT;
qdp->rate = rate * 128;
}
static __always_inline void hbm_init_edt_vqueue(struct hbm_vqueue *qdp,
int rate)
{
unsigned long long curtime;
curtime = bpf_ktime_get_ns();
bpf_printk("Initializing queue_state, rate:%d\n", rate * 128);
qdp->lasttime = curtime - BURST_SIZE_NS; // support initial burst
qdp->credit = 0; // not used
qdp->rate = rate * 128;
}
static __always_inline void hbm_update_stats(struct hbm_queue_stats *qsp,
int len,
unsigned long long curtime,
bool congestion_flag,
bool drop_flag,
bool cwr_flag,
bool ecn_ce_flag,
struct hbm_pkt_info *pkti,
int credit)
{
int rv = ALLOW_PKT;
if (qsp != NULL) {
// Following is needed for work conserving
__sync_add_and_fetch(&(qsp->bytes_total), len);
if (qsp->stats) {
// Optionally update statistics
if (qsp->firstPacketTime == 0)
qsp->firstPacketTime = curtime;
qsp->lastPacketTime = curtime;
__sync_add_and_fetch(&(qsp->pkts_total), 1);
if (congestion_flag) {
__sync_add_and_fetch(&(qsp->pkts_marked), 1);
__sync_add_and_fetch(&(qsp->bytes_marked), len);
}
if (drop_flag) {
__sync_add_and_fetch(&(qsp->pkts_dropped), 1);
__sync_add_and_fetch(&(qsp->bytes_dropped),
len);
}
if (ecn_ce_flag)
__sync_add_and_fetch(&(qsp->pkts_ecn_ce), 1);
if (pkti->cwnd) {
__sync_add_and_fetch(&(qsp->sum_cwnd),
pkti->cwnd);
__sync_add_and_fetch(&(qsp->sum_cwnd_cnt), 1);
}
if (pkti->rtt)
__sync_add_and_fetch(&(qsp->sum_rtt),
pkti->rtt);
__sync_add_and_fetch(&(qsp->sum_credit), credit);
if (drop_flag)
rv = DROP_PKT;
if (cwr_flag)
rv |= 2;
if (rv == DROP_PKT)
__sync_add_and_fetch(&(qsp->returnValCount[0]),
1);
else if (rv == ALLOW_PKT)
__sync_add_and_fetch(&(qsp->returnValCount[1]),
1);
else if (rv == 2)
__sync_add_and_fetch(&(qsp->returnValCount[2]),
1);
else if (rv == 3)
__sync_add_and_fetch(&(qsp->returnValCount[3]),
1);
}
}
}