// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2021-2022 Intel Corporation
*/
#include <uapi/linux/if_ether.h>
#include <uapi/linux/if_arp.h>
#include <uapi/linux/icmp.h>
#include <linux/etherdevice.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/ieee80211.h>
#include <net/cfg80211.h>
#include <net/ip.h>
#include <linux/if_arp.h>
#include <linux/icmp.h>
#include <linux/udp.h>
#include <linux/ip.h>
#include <linux/mm.h>
#include "internal.h"
#include "sap.h"
#include "iwl-mei.h"
/*
* Returns true if further filtering should be stopped. Only in that case
* pass_to_csme and rx_handler_res are set. Otherwise, next level of filters
* should be checked.
*/
static bool iwl_mei_rx_filter_eth(const struct ethhdr *ethhdr,
const struct iwl_sap_oob_filters *filters,
bool *pass_to_csme,
rx_handler_result_t *rx_handler_res)
{
const struct iwl_sap_eth_filter *filt;
/* This filter is not relevant for UCAST packet */
if (!is_multicast_ether_addr(ethhdr->h_dest) ||
is_broadcast_ether_addr(ethhdr->h_dest))
return false;
for (filt = &filters->eth_filters[0];
filt < &filters->eth_filters[0] + ARRAY_SIZE(filters->eth_filters);
filt++) {
/* Assume there are no enabled filter after a disabled one */
if (!(filt->flags & SAP_ETH_FILTER_ENABLED))
break;
if (compare_ether_header(filt->mac_address, ethhdr->h_dest))
continue;
/* Packet needs to reach the host's stack */
if (filt->flags & SAP_ETH_FILTER_COPY)
*rx_handler_res = RX_HANDLER_PASS;
else
*rx_handler_res = RX_HANDLER_CONSUMED;
/* We have an authoritative answer, stop filtering */
if (filt->flags & SAP_ETH_FILTER_STOP) {
*pass_to_csme = true;
return true;
}
return false;
}
/* MCAST frames that don't match layer 2 filters are not sent to ME */
*pass_to_csme = false;
return true;
}
/*
* Returns true iff the frame should be passed to CSME in which case
* rx_handler_res is set.
*/
static bool iwl_mei_rx_filter_arp(struct sk_buff *skb,
const struct iwl_sap_oob_filters *filters,
rx_handler_result_t *rx_handler_res)
{
const struct iwl_sap_ipv4_filter *filt = &filters->ipv4_filter;
const struct arphdr *arp;
const __be32 *target_ip;
u32 flags = le32_to_cpu(filt->flags);
if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
return false;
arp = arp_hdr(skb);
/* Handle only IPv4 over ethernet ARP frames */
if (arp->ar_hrd != htons(ARPHRD_ETHER) ||
arp->ar_pro != htons(ETH_P_IP))
return false;
/*
* After the ARP header, we have:
* src MAC address - 6 bytes
* src IP address - 4 bytes
* target MAC addess - 6 bytes
*/
target_ip = (const void *)((const u8 *)(arp + 1) +
ETH_ALEN + sizeof(__be32) + ETH_ALEN);
/*
* ARP request is forwarded to ME only if IP address match in the
* ARP request's target ip field.
*/
if (arp->ar_op == htons(ARPOP_REQUEST) &&
(filt->flags & cpu_to_le32(SAP_IPV4_FILTER_ARP_REQ_PASS)) &&
(filt->ipv4_addr == 0 || filt->ipv4_addr == *target_ip)) {
if (flags & SAP_IPV4_FILTER_ARP_REQ_COPY)
*rx_handler_res = RX_HANDLER_PASS;
else
*rx_handler_res = RX_HANDLER_CONSUMED;
return true;
}
/* ARP reply is always forwarded to ME regardless of the IP */
if (flags & SAP_IPV4_FILTER_ARP_RESP_PASS &&
arp->ar_op == htons(ARPOP_REPLY)) {
if (flags & SAP_IPV4_FILTER_ARP_RESP_COPY)
*rx_handler_res = RX_HANDLER_PASS;
else
*rx_handler_res = RX_HANDLER_CONSUMED;
return true;
}
return false;
}
static bool
iwl_mei_rx_filter_tcp_udp(struct sk_buff *skb, bool ip_match,
const struct iwl_sap_oob_filters *filters,
rx_handler_result_t *rx_handler_res)
{
const struct iwl_sap_flex_filter *filt;
for (filt = &filters->flex_filters[0];
filt < &filters->flex_filters[0] + ARRAY_SIZE(filters->flex_filters);
filt++) {
if (!(filt->flags & SAP_FLEX_FILTER_ENABLED))
break;
/*
* We are required to have a match on the IP level and we didn't
* have such match.
*/
if ((filt->flags &
(SAP_FLEX_FILTER_IPV4 | SAP_FLEX_FILTER_IPV6)) &&
!ip_match)
continue;
if ((filt->flags & SAP_FLEX_FILTER_UDP) &&
ip_hdr(skb)->protocol != IPPROTO_UDP)
continue;
if ((filt->flags & SAP_FLEX_FILTER_TCP) &&
ip_hdr(skb)->protocol != IPPROTO_TCP)
continue;
/*
* We must have either a TCP header or a UDP header, both
* starts with a source port and then a destination port.
* Both are big endian words.
* Use a UDP header and that will work for TCP as well.
*/
if ((filt->src_port && filt->src_port != udp_hdr(skb)->source) ||
(filt->dst_port && filt->dst_port != udp_hdr(skb)->dest))
continue;
if (filt->flags & SAP_FLEX_FILTER_COPY)
*rx_handler_res = RX_HANDLER_PASS;
else
*rx_handler_res = RX_HANDLER_CONSUMED;
return true;
}
return false;
}
static bool iwl_mei_rx_filter_ipv4(struct sk_buff *skb,
const struct iwl_sap_oob_filters *filters,
rx_handler_result_t *rx_handler_res)
{
const struct iwl_sap_ipv4_filter *filt = &filters->ipv4_filter;
const struct iphdr *iphdr;
unsigned int iphdrlen;
bool match;
if (!pskb_may_pull(skb, skb_network_offset(skb) + sizeof(*iphdr)) ||
!pskb_may_pull(skb, skb_network_offset(skb) + ip_hdrlen(skb)))
return false;
iphdrlen = ip_hdrlen(skb);
iphdr = ip_hdr(skb);
match = !filters->ipv4_filter.ipv4_addr ||
filters->ipv4_filter.ipv4_addr == iphdr->daddr;
skb_set_transport_header(skb, skb_network_offset(skb) + iphdrlen);
switch (ip_hdr(skb)->protocol) {
case IPPROTO_UDP:
case IPPROTO_TCP:
/*
* UDP header is shorter than TCP header and we look at the first bytes
* of the header anyway (see below).
* If we have a truncated TCP packet, let CSME handle this.
*/
if (!pskb_may_pull(skb, skb_transport_offset(skb) +
sizeof(struct udphdr)))
return false;
return iwl_mei_rx_filter_tcp_udp(skb, match,
filters, rx_handler_res);
case IPPROTO_ICMP: {
struct icmphdr *icmp;
if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(*icmp)))
return false;
icmp = icmp_hdr(skb);
/*
* Don't pass echo requests to ME even if it wants it as we
* want the host to answer.
*/
if ((filt->flags & cpu_to_le32(SAP_IPV4_FILTER_ICMP_PASS)) &&
match && (icmp->type != ICMP_ECHO || icmp->code != 0)) {
if (filt->flags & cpu_to_le32(SAP_IPV4_FILTER_ICMP_COPY))
*rx_handler_res = RX_HANDLER_PASS;
else
*rx_handler_res = RX_HANDLER_CONSUMED;
return true;
}
break;
}
case IPPROTO_ICMPV6:
/* TODO: Should we have the same ICMP request logic here too? */
if ((filters->icmpv6_flags & cpu_to_le32(SAP_ICMPV6_FILTER_ENABLED) &&
match)) {
if (filters->icmpv6_flags &
cpu_to_le32(SAP_ICMPV6_FILTER_COPY))
*rx_handler_res = RX_HANDLER_PASS;
else
*rx_handler_res = RX_HANDLER_CONSUMED;
return true;
}
break;
default:
return false;
}
return false;
}
static bool iwl_mei_rx_filter_ipv6(struct sk_buff *skb,
const struct iwl_sap_oob_filters *filters,
rx_handler_result_t *rx_handler_res)
{
*rx_handler_res = RX_HANDLER_PASS;
/* TODO */
return false;
}
static rx_handler_result_t
iwl_mei_rx_pass_to_csme(struct sk_buff *skb,
const struct iwl_sap_oob_filters *filters,
bool *pass_to_csme)
{
const struct ethhdr *ethhdr = (void *)skb_mac_header(skb);
rx_handler_result_t rx_handler_res = RX_HANDLER_PASS;
bool (*filt_handler)(struct sk_buff *skb,
const struct iwl_sap_oob_filters *filters,
rx_handler_result_t *rx_handler_res);
/*
* skb->data points the IP header / ARP header and the ETH header
* is in the headroom.
*/
skb_reset_network_header(skb);
/*
* MCAST IP packets sent by us are received again here without
* an ETH header. Drop them here.
*/
if (!skb_mac_offset(skb))
return RX_HANDLER_PASS;
if (skb_headroom(skb) < sizeof(*ethhdr))
return RX_HANDLER_PASS;
if (iwl_mei_rx_filter_eth(ethhdr, filters,
pass_to_csme, &rx_handler_res))
return rx_handler_res;
switch (skb->protocol) {
case htons(ETH_P_IP):
filt_handler = iwl_mei_rx_filter_ipv4;
break;
case htons(ETH_P_ARP):
filt_handler = iwl_mei_rx_filter_arp;
break;
case htons(ETH_P_IPV6):
filt_handler = iwl_mei_rx_filter_ipv6;
break;
default:
*pass_to_csme = false;
return rx_handler_res;
}
*pass_to_csme = filt_handler(skb, filters, &rx_handler_res);
return rx_handler_res;
}
rx_handler_result_t iwl_mei_rx_filter(struct sk_buff *orig_skb,
const struct iwl_sap_oob_filters *filters,
bool *pass_to_csme)
{
rx_handler_result_t ret;
struct sk_buff *skb;
ret = iwl_mei_rx_pass_to_csme(orig_skb, filters, pass_to_csme);
if (!*pass_to_csme)
return RX_HANDLER_PASS;
if (ret == RX_HANDLER_PASS) {
skb = skb_copy(orig_skb, GFP_ATOMIC);
if (!skb)
return RX_HANDLER_PASS;
} else {
skb = orig_skb;
}
/* CSME wants the MAC header as well, push it back */
skb_push(skb, skb->data - skb_mac_header(skb));
/*
* Add the packet that CSME wants to get to the ring. Don't send the
* Check Shared Area HECI message since this is not possible from the
* Rx context. The caller will schedule a worker to do just that.
*/
iwl_mei_add_data_to_ring(skb, false);
/*
* In case we drop the packet, don't free it, the caller will do that
* for us
*/
if (ret == RX_HANDLER_PASS)
dev_kfree_skb(skb);
return ret;
}
#define DHCP_SERVER_PORT 67
#define DHCP_CLIENT_PORT 68
void iwl_mei_tx_copy_to_csme(struct sk_buff *origskb, unsigned int ivlen)
{
struct ieee80211_hdr *hdr;
struct sk_buff *skb;
struct ethhdr ethhdr;
struct ethhdr *eth;
/* Catch DHCP packets */
if (origskb->protocol != htons(ETH_P_IP) ||
ip_hdr(origskb)->protocol != IPPROTO_UDP ||
udp_hdr(origskb)->source != htons(DHCP_CLIENT_PORT) ||
udp_hdr(origskb)->dest != htons(DHCP_SERVER_PORT))
return;
/*
* We could be a bit less aggressive here and not copy everything, but
* this is very rare anyway, do don't bother much.
*/
skb = skb_copy(origskb, GFP_ATOMIC);
if (!skb)
return;
skb->protocol = origskb->protocol;
hdr = (void *)skb->data;
memcpy(ethhdr.h_dest, ieee80211_get_DA(hdr), ETH_ALEN);
memcpy(ethhdr.h_source, ieee80211_get_SA(hdr), ETH_ALEN);
/*
* Remove the ieee80211 header + IV + SNAP but leave the ethertype
* We still have enough headroom for the sap header.
*/
pskb_pull(skb, ieee80211_hdrlen(hdr->frame_control) + ivlen + 6);
eth = skb_push(skb, sizeof(ethhdr.h_dest) + sizeof(ethhdr.h_source));
memcpy(eth, ðhdr, sizeof(ethhdr.h_dest) + sizeof(ethhdr.h_source));
iwl_mei_add_data_to_ring(skb, true);
dev_kfree_skb(skb);
}
EXPORT_SYMBOL_GPL(iwl_mei_tx_copy_to_csme);