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 int xfrm6_find_1stfragopt(struct xfrm_state *x, struct sk_buff *skb, 20 u8 **prevhdr) 21 { 22 return ip6_find_1stfragopt(skb, prevhdr); 23 } 24 EXPORT_SYMBOL(xfrm6_find_1stfragopt); 25 26 void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu) 27 { 28 struct flowi6 fl6; 29 struct sock *sk = skb->sk; 30 31 fl6.flowi6_oif = sk->sk_bound_dev_if; 32 fl6.daddr = ipv6_hdr(skb)->daddr; 33 34 ipv6_local_rxpmtu(sk, &fl6, mtu); 35 } 36 37 void xfrm6_local_error(struct sk_buff *skb, u32 mtu) 38 { 39 struct flowi6 fl6; 40 const struct ipv6hdr *hdr; 41 struct sock *sk = skb->sk; 42 43 hdr = skb->encapsulation ? inner_ipv6_hdr(skb) : ipv6_hdr(skb); 44 fl6.fl6_dport = inet_sk(sk)->inet_dport; 45 fl6.daddr = hdr->daddr; 46 47 ipv6_local_error(sk, EMSGSIZE, &fl6, mtu); 48 } 49 50 static int __xfrm6_output_finish(struct net *net, struct sock *sk, struct sk_buff *skb) 51 { 52 return xfrm_output(sk, skb); 53 } 54 55 static int __xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb) 56 { 57 struct dst_entry *dst = skb_dst(skb); 58 struct xfrm_state *x = dst->xfrm; 59 int mtu; 60 bool toobig; 61 62 #ifdef CONFIG_NETFILTER 63 if (!x) { 64 IP6CB(skb)->flags |= IP6SKB_REROUTED; 65 return dst_output(net, sk, skb); 66 } 67 #endif 68 69 if (x->props.mode != XFRM_MODE_TUNNEL) 70 goto skip_frag; 71 72 if (skb->protocol == htons(ETH_P_IPV6)) 73 mtu = ip6_skb_dst_mtu(skb); 74 else 75 mtu = dst_mtu(skb_dst(skb)); 76 77 toobig = skb->len > mtu && !skb_is_gso(skb); 78 79 if (toobig && xfrm6_local_dontfrag(skb->sk)) { 80 xfrm6_local_rxpmtu(skb, mtu); 81 kfree_skb(skb); 82 return -EMSGSIZE; 83 } else if (!skb->ignore_df && toobig && skb->sk) { 84 xfrm_local_error(skb, mtu); 85 kfree_skb(skb); 86 return -EMSGSIZE; 87 } 88 89 if (toobig || dst_allfrag(skb_dst(skb))) 90 return ip6_fragment(net, sk, skb, 91 __xfrm6_output_finish); 92 93 skip_frag: 94 return xfrm_output(sk, skb); 95 } 96 97 int xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb) 98 { 99 return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING, 100 net, sk, skb, skb->dev, skb_dst(skb)->dev, 101 __xfrm6_output, 102 !(IP6CB(skb)->flags & IP6SKB_REROUTED)); 103 } 104