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