Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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/skbuff.h> |
| 13 | #include <linux/spinlock.h> |
| 14 | #include <linux/icmpv6.h> |
| 15 | #include <net/dsfield.h> |
| 16 | #include <net/inet_ecn.h> |
| 17 | #include <net/ipv6.h> |
| 18 | #include <net/xfrm.h> |
| 19 | |
| 20 | /* Add encapsulation header. |
| 21 | * |
| 22 | * In transport mode, the IP header and mutable extension headers will be moved |
| 23 | * forward to make space for the encapsulation header. |
| 24 | * |
| 25 | * In tunnel mode, the top IP header will be constructed per RFC 2401. |
| 26 | * The following fields in it shall be filled in by x->type->output: |
| 27 | * payload_len |
| 28 | * |
| 29 | * On exit, skb->h will be set to the start of the encapsulation header to be |
| 30 | * filled in by x->type->output and skb->nh will be set to the nextheader field |
| 31 | * of the extension header directly preceding the encapsulation header, or in |
| 32 | * its absence, that of the top IP header. The value of skb->data will always |
| 33 | * point to the top IP header. |
| 34 | */ |
| 35 | static void xfrm6_encap(struct sk_buff *skb) |
| 36 | { |
| 37 | struct dst_entry *dst = skb->dst; |
| 38 | struct xfrm_state *x = dst->xfrm; |
| 39 | struct ipv6hdr *iph, *top_iph; |
| 40 | int dsfield; |
| 41 | |
| 42 | skb_push(skb, x->props.header_len); |
| 43 | iph = skb->nh.ipv6h; |
| 44 | |
| 45 | if (!x->props.mode) { |
| 46 | u8 *prevhdr; |
| 47 | int hdr_len; |
| 48 | |
| 49 | hdr_len = ip6_find_1stfragopt(skb, &prevhdr); |
| 50 | skb->nh.raw = prevhdr - x->props.header_len; |
| 51 | skb->h.raw = skb->data + hdr_len; |
| 52 | memmove(skb->data, iph, hdr_len); |
| 53 | return; |
| 54 | } |
| 55 | |
| 56 | skb->nh.raw = skb->data; |
| 57 | top_iph = skb->nh.ipv6h; |
| 58 | skb->nh.raw = &top_iph->nexthdr; |
| 59 | skb->h.ipv6h = top_iph + 1; |
| 60 | |
| 61 | top_iph->version = 6; |
| 62 | top_iph->priority = iph->priority; |
| 63 | top_iph->flow_lbl[0] = iph->flow_lbl[0]; |
| 64 | top_iph->flow_lbl[1] = iph->flow_lbl[1]; |
| 65 | top_iph->flow_lbl[2] = iph->flow_lbl[2]; |
| 66 | dsfield = ipv6_get_dsfield(top_iph); |
| 67 | dsfield = INET_ECN_encapsulate(dsfield, dsfield); |
| 68 | if (x->props.flags & XFRM_STATE_NOECN) |
| 69 | dsfield &= ~INET_ECN_MASK; |
| 70 | ipv6_change_dsfield(top_iph, 0, dsfield); |
| 71 | top_iph->nexthdr = IPPROTO_IPV6; |
| 72 | top_iph->hop_limit = dst_metric(dst->child, RTAX_HOPLIMIT); |
| 73 | ipv6_addr_copy(&top_iph->saddr, (struct in6_addr *)&x->props.saddr); |
| 74 | ipv6_addr_copy(&top_iph->daddr, (struct in6_addr *)&x->id.daddr); |
| 75 | } |
| 76 | |
| 77 | static int xfrm6_tunnel_check_size(struct sk_buff *skb) |
| 78 | { |
| 79 | int mtu, ret = 0; |
| 80 | struct dst_entry *dst = skb->dst; |
| 81 | |
| 82 | mtu = dst_mtu(dst); |
| 83 | if (mtu < IPV6_MIN_MTU) |
| 84 | mtu = IPV6_MIN_MTU; |
| 85 | |
| 86 | if (skb->len > mtu) { |
| 87 | icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, skb->dev); |
| 88 | ret = -EMSGSIZE; |
| 89 | } |
| 90 | |
| 91 | return ret; |
| 92 | } |
| 93 | |
| 94 | int xfrm6_output(struct sk_buff *skb) |
| 95 | { |
| 96 | struct dst_entry *dst = skb->dst; |
| 97 | struct xfrm_state *x = dst->xfrm; |
| 98 | int err; |
| 99 | |
| 100 | if (skb->ip_summed == CHECKSUM_HW) { |
| 101 | err = skb_checksum_help(skb, 0); |
| 102 | if (err) |
| 103 | goto error_nolock; |
| 104 | } |
| 105 | |
| 106 | if (x->props.mode) { |
| 107 | err = xfrm6_tunnel_check_size(skb); |
| 108 | if (err) |
| 109 | goto error_nolock; |
| 110 | } |
| 111 | |
| 112 | spin_lock_bh(&x->lock); |
| 113 | err = xfrm_state_check(x, skb); |
| 114 | if (err) |
| 115 | goto error; |
| 116 | |
| 117 | xfrm6_encap(skb); |
| 118 | |
| 119 | err = x->type->output(x, skb); |
| 120 | if (err) |
| 121 | goto error; |
| 122 | |
| 123 | x->curlft.bytes += skb->len; |
| 124 | x->curlft.packets++; |
| 125 | |
| 126 | spin_unlock_bh(&x->lock); |
| 127 | |
| 128 | skb->nh.raw = skb->data; |
| 129 | |
| 130 | if (!(skb->dst = dst_pop(dst))) { |
| 131 | err = -EHOSTUNREACH; |
| 132 | goto error_nolock; |
| 133 | } |
| 134 | err = NET_XMIT_BYPASS; |
| 135 | |
| 136 | out_exit: |
| 137 | return err; |
| 138 | error: |
| 139 | spin_unlock_bh(&x->lock); |
| 140 | error_nolock: |
| 141 | kfree_skb(skb); |
| 142 | goto out_exit; |
| 143 | } |