diff options
Diffstat (limited to 'net/netfilter/nft_chain_route.c')
-rw-r--r-- | net/netfilter/nft_chain_route.c | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/net/netfilter/nft_chain_route.c b/net/netfilter/nft_chain_route.c new file mode 100644 index 0000000000..925db0dce4 --- /dev/null +++ b/net/netfilter/nft_chain_route.c @@ -0,0 +1,169 @@ +// 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 +} |