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// SPDX-License-Identifier: GPL-2.0
#include <linux/skbuff.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv4.h>
#include <linux/netfilter_ipv6.h>
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables_ipv4.h>
#include <net/netfilter/nf_tables_ipv6.h>
#include <net/route.h>
#include <net/ip.h>
#ifdef CONFIG_NF_TABLES_IPV4
static unsigned int nf_route_table_hook4(void *priv,
struct sk_buff *skb,
const struct nf_hook_state *state)
{
const struct iphdr *iph;
struct nft_pktinfo pkt;
__be32 saddr, daddr;
unsigned int ret;
u32 mark;
int err;
u8 tos;
nft_set_pktinfo(&pkt, skb, state);
nft_set_pktinfo_ipv4(&pkt);
mark = skb->mark;
iph = ip_hdr(skb);
saddr = iph->saddr;
daddr = iph->daddr;
tos = iph->tos;
ret = nft_do_chain(&pkt, priv);
if (ret == NF_ACCEPT) {
iph = ip_hdr(skb);
if (iph->saddr != saddr ||
iph->daddr != daddr ||
skb->mark != mark ||
iph->tos != tos) {
err = ip_route_me_harder(state->net, state->sk, skb, RTN_UNSPEC);
if (err < 0)
ret = NF_DROP_ERR(err);
}
}
return ret;
}
static const struct nft_chain_type nft_chain_route_ipv4 = {
.name = "route",
.type = NFT_CHAIN_T_ROUTE,
.family = NFPROTO_IPV4,
.hook_mask = (1 << NF_INET_LOCAL_OUT),
.hooks = {
[NF_INET_LOCAL_OUT] = nf_route_table_hook4,
},
};
#endif
#ifdef CONFIG_NF_TABLES_IPV6
static unsigned int nf_route_table_hook6(void *priv,
struct sk_buff *skb,
const struct nf_hook_state *state)
{
struct in6_addr saddr, daddr;
struct nft_pktinfo pkt;
u32 mark, flowlabel;
unsigned int ret;
u8 hop_limit;
int err;
nft_set_pktinfo(&pkt, skb, state);
nft_set_pktinfo_ipv6(&pkt);
/* save source/dest address, mark, hoplimit, flowlabel, priority */
memcpy(&saddr, &ipv6_hdr(skb)->saddr, sizeof(saddr));
memcpy(&daddr, &ipv6_hdr(skb)->daddr, sizeof(daddr));
mark = skb->mark;
hop_limit = ipv6_hdr(skb)->hop_limit;
/* flowlabel and prio (includes version, which shouldn't change either)*/
flowlabel = *((u32 *)ipv6_hdr(skb));
ret = nft_do_chain(&pkt, priv);
if (ret == NF_ACCEPT &&
(memcmp(&ipv6_hdr(skb)->saddr, &saddr, sizeof(saddr)) ||
memcmp(&ipv6_hdr(skb)->daddr, &daddr, sizeof(daddr)) ||
skb->mark != mark ||
ipv6_hdr(skb)->hop_limit != hop_limit ||
flowlabel != *((u32 *)ipv6_hdr(skb)))) {
err = nf_ip6_route_me_harder(state->net, state->sk, skb);
if (err < 0)
ret = NF_DROP_ERR(err);
}
return ret;
}
static const struct nft_chain_type nft_chain_route_ipv6 = {
.name = "route",
.type = NFT_CHAIN_T_ROUTE,
.family = NFPROTO_IPV6,
.hook_mask = (1 << NF_INET_LOCAL_OUT),
.hooks = {
[NF_INET_LOCAL_OUT] = nf_route_table_hook6,
},
};
#endif
#ifdef CONFIG_NF_TABLES_INET
static unsigned int nf_route_table_inet(void *priv,
struct sk_buff *skb,
const struct nf_hook_state *state)
{
struct nft_pktinfo pkt;
switch (state->pf) {
case NFPROTO_IPV4:
return nf_route_table_hook4(priv, skb, state);
case NFPROTO_IPV6:
return nf_route_table_hook6(priv, skb, state);
default:
nft_set_pktinfo(&pkt, skb, state);
break;
}
return nft_do_chain(&pkt, priv);
}
static const struct nft_chain_type nft_chain_route_inet = {
.name = "route",
.type = NFT_CHAIN_T_ROUTE,
.family = NFPROTO_INET,
.hook_mask = (1 << NF_INET_LOCAL_OUT),
.hooks = {
[NF_INET_LOCAL_OUT] = nf_route_table_inet,
},
};
#endif
void __init nft_chain_route_init(void)
{
#ifdef CONFIG_NF_TABLES_IPV6
nft_register_chain_type(&nft_chain_route_ipv6);
#endif
#ifdef CONFIG_NF_TABLES_IPV4
nft_register_chain_type(&nft_chain_route_ipv4);
#endif
#ifdef CONFIG_NF_TABLES_INET
nft_register_chain_type(&nft_chain_route_inet);
#endif
}
void __exit nft_chain_route_fini(void)
{
#ifdef CONFIG_NF_TABLES_IPV6
nft_unregister_chain_type(&nft_chain_route_ipv6);
#endif
#ifdef CONFIG_NF_TABLES_IPV4
nft_unregister_chain_type(&nft_chain_route_ipv4);
#endif
#ifdef CONFIG_NF_TABLES_INET
nft_unregister_chain_type(&nft_chain_route_inet);
#endif
}
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