1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 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> 6 */ 7 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> 14 #include <net/dst.h> 15 #include <net/ipv6.h> 16 #include <net/ip6_route.h> 17 #include <net/xfrm.h> 18 19 void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu) 20 { 21 struct flowi6 fl6; 22 struct sock *sk = skb->sk; 23 24 fl6.flowi6_oif = sk->sk_bound_dev_if; 25 fl6.daddr = ipv6_hdr(skb)->daddr; 26 27 ipv6_local_rxpmtu(sk, &fl6, mtu); 28 } 29 30 void xfrm6_local_error(struct sk_buff *skb, u32 mtu) 31 { 32 struct flowi6 fl6; 33 const struct ipv6hdr *hdr; 34 struct sock *sk = skb->sk; 35 36 hdr = skb->encapsulation ? inner_ipv6_hdr(skb) : ipv6_hdr(skb); 37 fl6.fl6_dport = inet_sk(sk)->inet_dport; 38 fl6.daddr = hdr->daddr; 39 40 ipv6_local_error(sk, EMSGSIZE, &fl6, mtu); 41 } 42 43 static int __xfrm6_output_finish(struct net *net, struct sock *sk, struct sk_buff *skb) 44 { 45 return xfrm_output(sk, skb); 46 } 47 48 static int __xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb) 49 { 50 struct dst_entry *dst = skb_dst(skb); 51 struct xfrm_state *x = dst->xfrm; 52 unsigned int mtu; 53 bool toobig; 54 55 #ifdef CONFIG_NETFILTER 56 if (!x) { 57 IP6CB(skb)->flags |= IP6SKB_REROUTED; 58 return dst_output(net, sk, skb); 59 } 60 #endif 61 62 if (x->props.mode != XFRM_MODE_TUNNEL) 63 goto skip_frag; 64 65 if (skb->protocol == htons(ETH_P_IPV6)) 66 mtu = ip6_skb_dst_mtu(skb); 67 else 68 mtu = dst_mtu(skb_dst(skb)); 69 70 toobig = skb->len > mtu && !skb_is_gso(skb); 71 72 if (toobig && xfrm6_local_dontfrag(skb->sk)) { 73 xfrm6_local_rxpmtu(skb, mtu); 74 kfree_skb(skb); 75 return -EMSGSIZE; 76 } else if (!skb->ignore_df && toobig && skb->sk) { 77 xfrm_local_error(skb, mtu); 78 kfree_skb(skb); 79 return -EMSGSIZE; 80 } 81 82 if (toobig || dst_allfrag(skb_dst(skb))) 83 return ip6_fragment(net, sk, skb, 84 __xfrm6_output_finish); 85 86 skip_frag: 87 return xfrm_output(sk, skb); 88 } 89 90 int xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb) 91 { 92 return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING, 93 net, sk, skb, skb->dev, skb_dst(skb)->dev, 94 __xfrm6_output, 95 !(IP6CB(skb)->flags & IP6SKB_REROUTED)); 96 } 97