1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * xfrm6_output.c - Common IPsec encapsulation code for IPv6.
4 * Copyright (C) 2002 USAGI/WIDE Project
5 * Copyright (c) 2004 Herbert Xu <herbert@gondor.apana.org.au>
8 #include <linux/if_ether.h>
9 #include <linux/kernel.h>
10 #include <linux/module.h>
11 #include <linux/skbuff.h>
12 #include <linux/icmpv6.h>
13 #include <linux/netfilter_ipv6.h>
16 #include <net/ip6_route.h>
19 int xfrm6_find_1stfragopt(struct xfrm_state *x, struct sk_buff *skb,
22 return ip6_find_1stfragopt(skb, prevhdr);
24 EXPORT_SYMBOL(xfrm6_find_1stfragopt);
26 static int xfrm6_local_dontfrag(struct sk_buff *skb)
29 struct sock *sk = skb->sk;
32 if (sk->sk_family != AF_INET6)
35 proto = sk->sk_protocol;
36 if (proto == IPPROTO_UDP || proto == IPPROTO_RAW)
37 return inet6_sk(sk)->dontfrag;
43 static void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu)
46 struct sock *sk = skb->sk;
48 fl6.flowi6_oif = sk->sk_bound_dev_if;
49 fl6.daddr = ipv6_hdr(skb)->daddr;
51 ipv6_local_rxpmtu(sk, &fl6, mtu);
54 void xfrm6_local_error(struct sk_buff *skb, u32 mtu)
57 const struct ipv6hdr *hdr;
58 struct sock *sk = skb->sk;
60 hdr = skb->encapsulation ? inner_ipv6_hdr(skb) : ipv6_hdr(skb);
61 fl6.fl6_dport = inet_sk(sk)->inet_dport;
62 fl6.daddr = hdr->daddr;
64 ipv6_local_error(sk, EMSGSIZE, &fl6, mtu);
67 static int xfrm6_tunnel_check_size(struct sk_buff *skb)
70 struct dst_entry *dst = skb_dst(skb);
76 if (mtu < IPV6_MIN_MTU)
79 if ((!skb_is_gso(skb) && skb->len > mtu) ||
81 !skb_gso_validate_network_len(skb, ip6_skb_dst_mtu(skb)))) {
83 skb->protocol = htons(ETH_P_IPV6);
85 if (xfrm6_local_dontfrag(skb))
86 xfrm6_local_rxpmtu(skb, mtu);
88 xfrm_local_error(skb, mtu);
90 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
97 int xfrm6_extract_output(struct xfrm_state *x, struct sk_buff *skb)
101 err = xfrm6_tunnel_check_size(skb);
105 XFRM_MODE_SKB_CB(skb)->protocol = ipv6_hdr(skb)->nexthdr;
107 return xfrm6_extract_header(skb);
110 int xfrm6_output_finish(struct sock *sk, struct sk_buff *skb)
112 memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
114 #ifdef CONFIG_NETFILTER
115 IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
118 return xfrm_output(sk, skb);
121 static int __xfrm6_output_state_finish(struct xfrm_state *x, struct sock *sk,
124 const struct xfrm_state_afinfo *afinfo;
125 int ret = -EAFNOSUPPORT;
128 afinfo = xfrm_state_afinfo_get_rcu(x->outer_mode.family);
130 ret = afinfo->output_finish(sk, skb);
138 static int __xfrm6_output_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
140 struct xfrm_state *x = skb_dst(skb)->xfrm;
142 return __xfrm6_output_state_finish(x, sk, skb);
145 static int __xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
147 struct dst_entry *dst = skb_dst(skb);
148 struct xfrm_state *x = dst->xfrm;
152 #ifdef CONFIG_NETFILTER
154 IP6CB(skb)->flags |= IP6SKB_REROUTED;
155 return dst_output(net, sk, skb);
159 if (x->props.mode != XFRM_MODE_TUNNEL)
162 if (skb->protocol == htons(ETH_P_IPV6))
163 mtu = ip6_skb_dst_mtu(skb);
165 mtu = dst_mtu(skb_dst(skb));
167 toobig = skb->len > mtu && !skb_is_gso(skb);
169 if (toobig && xfrm6_local_dontfrag(skb)) {
170 xfrm6_local_rxpmtu(skb, mtu);
173 } else if (!skb->ignore_df && toobig && skb->sk) {
174 xfrm_local_error(skb, mtu);
179 if (toobig || dst_allfrag(skb_dst(skb)))
180 return ip6_fragment(net, sk, skb,
181 __xfrm6_output_finish);
184 return __xfrm6_output_state_finish(x, sk, skb);
187 int xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
189 return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
190 net, sk, skb, NULL, skb_dst(skb)->dev,
192 !(IP6CB(skb)->flags & IP6SKB_REROUTED));