1 /* 2 * xfrm6_output.c - Common IPsec encapsulation code for IPv6. 3 * Copyright (C) 2002 USAGI/WIDE Project 4 * Copyright (c) 2004 Herbert Xu <herbert@gondor.apana.org.au> 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License 8 * as published by the Free Software Foundation; either version 9 * 2 of the License, or (at your option) any later version. 10 */ 11 12 #include <linux/if_ether.h> 13 #include <linux/kernel.h> 14 #include <linux/module.h> 15 #include <linux/skbuff.h> 16 #include <linux/icmpv6.h> 17 #include <linux/netfilter_ipv6.h> 18 #include <net/dst.h> 19 #include <net/ipv6.h> 20 #include <net/ip6_route.h> 21 #include <net/xfrm.h> 22 23 int xfrm6_find_1stfragopt(struct xfrm_state *x, struct sk_buff *skb, 24 u8 **prevhdr) 25 { 26 return ip6_find_1stfragopt(skb, prevhdr); 27 } 28 EXPORT_SYMBOL(xfrm6_find_1stfragopt); 29 30 static int xfrm6_local_dontfrag(struct sk_buff *skb) 31 { 32 int proto; 33 struct sock *sk = skb->sk; 34 35 if (sk) { 36 if (sk->sk_family != AF_INET6) 37 return 0; 38 39 proto = sk->sk_protocol; 40 if (proto == IPPROTO_UDP || proto == IPPROTO_RAW) 41 return inet6_sk(sk)->dontfrag; 42 } 43 44 return 0; 45 } 46 47 static void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu) 48 { 49 struct flowi6 fl6; 50 struct sock *sk = skb->sk; 51 52 fl6.flowi6_oif = sk->sk_bound_dev_if; 53 fl6.daddr = ipv6_hdr(skb)->daddr; 54 55 ipv6_local_rxpmtu(sk, &fl6, mtu); 56 } 57 58 void xfrm6_local_error(struct sk_buff *skb, u32 mtu) 59 { 60 struct flowi6 fl6; 61 const struct ipv6hdr *hdr; 62 struct sock *sk = skb->sk; 63 64 hdr = skb->encapsulation ? inner_ipv6_hdr(skb) : ipv6_hdr(skb); 65 fl6.fl6_dport = inet_sk(sk)->inet_dport; 66 fl6.daddr = hdr->daddr; 67 68 ipv6_local_error(sk, EMSGSIZE, &fl6, mtu); 69 } 70 71 static int xfrm6_tunnel_check_size(struct sk_buff *skb) 72 { 73 int mtu, ret = 0; 74 struct dst_entry *dst = skb_dst(skb); 75 76 mtu = dst_mtu(dst); 77 if (mtu < IPV6_MIN_MTU) 78 mtu = IPV6_MIN_MTU; 79 80 if (!skb->ignore_df && skb->len > mtu) { 81 skb->dev = dst->dev; 82 83 if (xfrm6_local_dontfrag(skb)) 84 xfrm6_local_rxpmtu(skb, mtu); 85 else if (skb->sk) 86 xfrm_local_error(skb, mtu); 87 else 88 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); 89 ret = -EMSGSIZE; 90 } 91 92 return ret; 93 } 94 95 int xfrm6_extract_output(struct xfrm_state *x, struct sk_buff *skb) 96 { 97 int err; 98 99 err = xfrm6_tunnel_check_size(skb); 100 if (err) 101 return err; 102 103 XFRM_MODE_SKB_CB(skb)->protocol = ipv6_hdr(skb)->nexthdr; 104 105 return xfrm6_extract_header(skb); 106 } 107 108 int xfrm6_prepare_output(struct xfrm_state *x, struct sk_buff *skb) 109 { 110 int err; 111 112 err = xfrm_inner_extract_output(x, skb); 113 if (err) 114 return err; 115 116 skb->ignore_df = 1; 117 skb->protocol = htons(ETH_P_IPV6); 118 119 return x->outer_mode->output2(x, skb); 120 } 121 EXPORT_SYMBOL(xfrm6_prepare_output); 122 123 int xfrm6_output_finish(struct sock *sk, struct sk_buff *skb) 124 { 125 memset(IP6CB(skb), 0, sizeof(*IP6CB(skb))); 126 127 #ifdef CONFIG_NETFILTER 128 IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED; 129 #endif 130 131 return xfrm_output(sk, skb); 132 } 133 134 static int __xfrm6_output_finish(struct net *net, struct sock *sk, struct sk_buff *skb) 135 { 136 struct xfrm_state *x = skb_dst(skb)->xfrm; 137 138 return x->outer_mode->afinfo->output_finish(sk, skb); 139 } 140 141 static int __xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb) 142 { 143 struct dst_entry *dst = skb_dst(skb); 144 struct xfrm_state *x = dst->xfrm; 145 int mtu; 146 147 #ifdef CONFIG_NETFILTER 148 if (!x) { 149 IP6CB(skb)->flags |= IP6SKB_REROUTED; 150 return dst_output(sk, skb); 151 } 152 #endif 153 154 if (skb->protocol == htons(ETH_P_IPV6)) 155 mtu = ip6_skb_dst_mtu(skb); 156 else 157 mtu = dst_mtu(skb_dst(skb)); 158 159 if (skb->len > mtu && xfrm6_local_dontfrag(skb)) { 160 xfrm6_local_rxpmtu(skb, mtu); 161 return -EMSGSIZE; 162 } else if (!skb->ignore_df && skb->len > mtu && skb->sk) { 163 xfrm_local_error(skb, mtu); 164 return -EMSGSIZE; 165 } 166 167 if (x->props.mode == XFRM_MODE_TUNNEL && 168 ((skb->len > mtu && !skb_is_gso(skb)) || 169 dst_allfrag(skb_dst(skb)))) { 170 return ip6_fragment(net, sk, skb, 171 __xfrm6_output_finish); 172 } 173 return x->outer_mode->afinfo->output_finish(sk, skb); 174 } 175 176 int xfrm6_output(struct sock *sk, struct sk_buff *skb) 177 { 178 struct net *net = dev_net(skb_dst(skb)->dev); 179 180 return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING, 181 net, sk, skb, NULL, skb_dst(skb)->dev, 182 __xfrm6_output, 183 !(IP6CB(skb)->flags & IP6SKB_REROUTED)); 184 } 185