| 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 | |
| 29 | EXPORT_SYMBOL(xfrm6_find_1stfragopt); |
| 30 | |
| 31 | static int xfrm6_local_dontfrag(struct sk_buff *skb) |
| 32 | { |
| 33 | int proto; |
| 34 | struct sock *sk = skb->sk; |
| 35 | |
| 36 | if (sk) { |
| 37 | proto = sk->sk_protocol; |
| 38 | |
| 39 | if (proto == IPPROTO_UDP || proto == IPPROTO_RAW) |
| 40 | return inet6_sk(sk)->dontfrag; |
| 41 | } |
| 42 | |
| 43 | return 0; |
| 44 | } |
| 45 | |
| 46 | static void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu) |
| 47 | { |
| 48 | struct flowi6 fl6; |
| 49 | struct sock *sk = skb->sk; |
| 50 | |
| 51 | fl6.flowi6_oif = sk->sk_bound_dev_if; |
| 52 | fl6.daddr = ipv6_hdr(skb)->daddr; |
| 53 | |
| 54 | ipv6_local_rxpmtu(sk, &fl6, mtu); |
| 55 | } |
| 56 | |
| 57 | static void xfrm6_local_error(struct sk_buff *skb, u32 mtu) |
| 58 | { |
| 59 | struct flowi6 fl6; |
| 60 | struct sock *sk = skb->sk; |
| 61 | |
| 62 | fl6.fl6_dport = inet_sk(sk)->inet_dport; |
| 63 | fl6.daddr = ipv6_hdr(skb)->daddr; |
| 64 | |
| 65 | ipv6_local_error(sk, EMSGSIZE, &fl6, mtu); |
| 66 | } |
| 67 | |
| 68 | static int xfrm6_tunnel_check_size(struct sk_buff *skb) |
| 69 | { |
| 70 | int mtu, ret = 0; |
| 71 | struct dst_entry *dst = skb_dst(skb); |
| 72 | |
| 73 | mtu = dst_mtu(dst); |
| 74 | if (mtu < IPV6_MIN_MTU) |
| 75 | mtu = IPV6_MIN_MTU; |
| 76 | |
| 77 | if (!skb->local_df && skb->len > mtu) { |
| 78 | skb->dev = dst->dev; |
| 79 | |
| 80 | if (xfrm6_local_dontfrag(skb)) |
| 81 | xfrm6_local_rxpmtu(skb, mtu); |
| 82 | else if (skb->sk) |
| 83 | xfrm6_local_error(skb, mtu); |
| 84 | else |
| 85 | icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); |
| 86 | ret = -EMSGSIZE; |
| 87 | } |
| 88 | |
| 89 | return ret; |
| 90 | } |
| 91 | |
| 92 | int xfrm6_extract_output(struct xfrm_state *x, struct sk_buff *skb) |
| 93 | { |
| 94 | int err; |
| 95 | |
| 96 | err = xfrm6_tunnel_check_size(skb); |
| 97 | if (err) |
| 98 | return err; |
| 99 | |
| 100 | XFRM_MODE_SKB_CB(skb)->protocol = ipv6_hdr(skb)->nexthdr; |
| 101 | |
| 102 | return xfrm6_extract_header(skb); |
| 103 | } |
| 104 | |
| 105 | int xfrm6_prepare_output(struct xfrm_state *x, struct sk_buff *skb) |
| 106 | { |
| 107 | int err; |
| 108 | |
| 109 | err = xfrm_inner_extract_output(x, skb); |
| 110 | if (err) |
| 111 | return err; |
| 112 | |
| 113 | memset(IP6CB(skb), 0, sizeof(*IP6CB(skb))); |
| 114 | #ifdef CONFIG_NETFILTER |
| 115 | IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED; |
| 116 | #endif |
| 117 | |
| 118 | skb->protocol = htons(ETH_P_IPV6); |
| 119 | skb->local_df = 1; |
| 120 | |
| 121 | return x->outer_mode->output2(x, skb); |
| 122 | } |
| 123 | EXPORT_SYMBOL(xfrm6_prepare_output); |
| 124 | |
| 125 | int xfrm6_output_finish(struct sk_buff *skb) |
| 126 | { |
| 127 | #ifdef CONFIG_NETFILTER |
| 128 | IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED; |
| 129 | #endif |
| 130 | |
| 131 | skb->protocol = htons(ETH_P_IPV6); |
| 132 | return xfrm_output(skb); |
| 133 | } |
| 134 | |
| 135 | static int __xfrm6_output(struct sk_buff *skb) |
| 136 | { |
| 137 | struct dst_entry *dst = skb_dst(skb); |
| 138 | struct xfrm_state *x = dst->xfrm; |
| 139 | int mtu = ip6_skb_dst_mtu(skb); |
| 140 | |
| 141 | if (skb->len > mtu && xfrm6_local_dontfrag(skb)) { |
| 142 | xfrm6_local_rxpmtu(skb, mtu); |
| 143 | return -EMSGSIZE; |
| 144 | } else if (!skb->local_df && skb->len > mtu && skb->sk) { |
| 145 | xfrm6_local_error(skb, mtu); |
| 146 | return -EMSGSIZE; |
| 147 | } |
| 148 | |
| 149 | if (x->props.mode == XFRM_MODE_TUNNEL && |
| 150 | ((skb->len > mtu && !skb_is_gso(skb)) || |
| 151 | dst_allfrag(skb_dst(skb)))) { |
| 152 | return ip6_fragment(skb, x->outer_mode->afinfo->output_finish); |
| 153 | } |
| 154 | return x->outer_mode->afinfo->output_finish(skb); |
| 155 | } |
| 156 | |
| 157 | int xfrm6_output(struct sk_buff *skb) |
| 158 | { |
| 159 | return NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING, skb, NULL, |
| 160 | skb_dst(skb)->dev, __xfrm6_output); |
| 161 | } |