Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 1 | /* |
| 2 | * xfrm4_mode_tunnel.c - Tunnel mode encapsulation for IPv4. |
| 3 | * |
| 4 | * Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au> |
| 5 | */ |
| 6 | |
| 7 | #include <linux/init.h> |
| 8 | #include <linux/kernel.h> |
| 9 | #include <linux/module.h> |
| 10 | #include <linux/skbuff.h> |
| 11 | #include <linux/stringify.h> |
| 12 | #include <net/dst.h> |
| 13 | #include <net/inet_ecn.h> |
| 14 | #include <net/ip.h> |
| 15 | #include <net/xfrm.h> |
| 16 | |
| 17 | static inline void ipip_ecn_decapsulate(struct sk_buff *skb) |
| 18 | { |
Arnaldo Carvalho de Melo | b0061ce | 2007-04-25 18:02:22 -0700 | [diff] [blame] | 19 | struct iphdr *inner_iph = ipip_hdr(skb); |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 20 | |
Herbert Xu | 227620e | 2007-11-13 21:41:28 -0800 | [diff] [blame] | 21 | if (INET_ECN_is_ce(XFRM_MODE_SKB_CB(skb)->tos)) |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 22 | IP_ECN_set_ce(inner_iph); |
| 23 | } |
| 24 | |
| 25 | /* Add encapsulation header. |
| 26 | * |
Herbert Xu | ceb1eec8 | 2007-10-10 15:45:52 -0700 | [diff] [blame] | 27 | * The top IP header will be constructed per RFC 2401. |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 28 | */ |
Herbert Xu | 195ad6a | 2007-12-20 13:53:40 -0800 | [diff] [blame] | 29 | static int xfrm4_mode_tunnel_output(struct xfrm_state *x, struct sk_buff *skb) |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 30 | { |
| 31 | struct dst_entry *dst = skb->dst; |
Herbert Xu | 36cf9ac | 2007-11-13 21:40:52 -0800 | [diff] [blame] | 32 | struct iphdr *top_iph; |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 33 | int flags; |
| 34 | |
Herbert Xu | 7b277b1 | 2007-10-10 15:44:06 -0700 | [diff] [blame] | 35 | skb_set_network_header(skb, -x->props.header_len); |
Herbert Xu | 37fedd3 | 2007-10-10 15:44:44 -0700 | [diff] [blame] | 36 | skb->mac_header = skb->network_header + |
| 37 | offsetof(struct iphdr, protocol); |
Herbert Xu | 36cf9ac | 2007-11-13 21:40:52 -0800 | [diff] [blame] | 38 | skb->transport_header = skb->network_header + sizeof(*top_iph); |
Arnaldo Carvalho de Melo | eddc9ec | 2007-04-20 22:47:35 -0700 | [diff] [blame] | 39 | top_iph = ip_hdr(skb); |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 40 | |
| 41 | top_iph->ihl = 5; |
| 42 | top_iph->version = 4; |
| 43 | |
Kazunori MIYAZAWA | df9dcb4 | 2008-03-24 14:51:51 -0700 | [diff] [blame] | 44 | top_iph->protocol = xfrm_af2proto(skb->dst->ops->family); |
Miika Komu | c82f963 | 2007-02-06 14:27:02 -0800 | [diff] [blame] | 45 | |
| 46 | /* DS disclosed */ |
Herbert Xu | 36cf9ac | 2007-11-13 21:40:52 -0800 | [diff] [blame] | 47 | top_iph->tos = INET_ECN_encapsulate(XFRM_MODE_SKB_CB(skb)->tos, |
| 48 | XFRM_MODE_SKB_CB(skb)->tos); |
Miika Komu | c82f963 | 2007-02-06 14:27:02 -0800 | [diff] [blame] | 49 | |
Herbert Xu | 36cf9ac | 2007-11-13 21:40:52 -0800 | [diff] [blame] | 50 | flags = x->props.flags; |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 51 | if (flags & XFRM_STATE_NOECN) |
| 52 | IP_ECN_clear(top_iph); |
| 53 | |
Herbert Xu | 36cf9ac | 2007-11-13 21:40:52 -0800 | [diff] [blame] | 54 | top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) ? |
Steffen Klassert | fe833fc | 2008-06-17 16:37:13 -0700 | [diff] [blame^] | 55 | 0 : (XFRM_MODE_SKB_CB(skb)->frag_off & htons(IP_DF)); |
Herbert Xu | 36cf9ac | 2007-11-13 21:40:52 -0800 | [diff] [blame] | 56 | ip_select_ident(top_iph, dst->child, NULL); |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 57 | |
| 58 | top_iph->ttl = dst_metric(dst->child, RTAX_HOPLIMIT); |
| 59 | |
| 60 | top_iph->saddr = x->props.saddr.a4; |
| 61 | top_iph->daddr = x->id.daddr.a4; |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 62 | |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 63 | return 0; |
| 64 | } |
| 65 | |
Herbert Xu | 195ad6a | 2007-12-20 13:53:40 -0800 | [diff] [blame] | 66 | static int xfrm4_mode_tunnel_input(struct xfrm_state *x, struct sk_buff *skb) |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 67 | { |
Arnaldo Carvalho de Melo | 39f69c6 | 2007-03-10 12:40:27 -0300 | [diff] [blame] | 68 | const unsigned char *old_mac; |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 69 | int err = -EINVAL; |
| 70 | |
Herbert Xu | 227620e | 2007-11-13 21:41:28 -0800 | [diff] [blame] | 71 | if (XFRM_MODE_SKB_CB(skb)->protocol != IPPROTO_IPIP) |
| 72 | goto out; |
Miika Komu | c82f963 | 2007-02-06 14:27:02 -0800 | [diff] [blame] | 73 | |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 74 | if (!pskb_may_pull(skb, sizeof(struct iphdr))) |
| 75 | goto out; |
| 76 | |
| 77 | if (skb_cloned(skb) && |
| 78 | (err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC))) |
| 79 | goto out; |
| 80 | |
Herbert Xu | 227620e | 2007-11-13 21:41:28 -0800 | [diff] [blame] | 81 | if (x->props.flags & XFRM_STATE_DECAP_DSCP) |
| 82 | ipv4_copy_dscp(XFRM_MODE_SKB_CB(skb)->tos, ipip_hdr(skb)); |
| 83 | if (!(x->props.flags & XFRM_STATE_NOECN)) |
| 84 | ipip_ecn_decapsulate(skb); |
| 85 | |
Arnaldo Carvalho de Melo | 98e399f | 2007-03-19 15:33:04 -0700 | [diff] [blame] | 86 | old_mac = skb_mac_header(skb); |
Arnaldo Carvalho de Melo | 39f69c6 | 2007-03-10 12:40:27 -0300 | [diff] [blame] | 87 | skb_set_mac_header(skb, -skb->mac_len); |
Arnaldo Carvalho de Melo | 98e399f | 2007-03-19 15:33:04 -0700 | [diff] [blame] | 88 | memmove(skb_mac_header(skb), old_mac, skb->mac_len); |
Arnaldo Carvalho de Melo | c1d2bbe | 2007-04-10 20:45:18 -0700 | [diff] [blame] | 89 | skb_reset_network_header(skb); |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 90 | err = 0; |
| 91 | |
| 92 | out: |
| 93 | return err; |
| 94 | } |
| 95 | |
| 96 | static struct xfrm_mode xfrm4_tunnel_mode = { |
Herbert Xu | 195ad6a | 2007-12-20 13:53:40 -0800 | [diff] [blame] | 97 | .input2 = xfrm4_mode_tunnel_input, |
Herbert Xu | 227620e | 2007-11-13 21:41:28 -0800 | [diff] [blame] | 98 | .input = xfrm_prepare_input, |
Herbert Xu | 195ad6a | 2007-12-20 13:53:40 -0800 | [diff] [blame] | 99 | .output2 = xfrm4_mode_tunnel_output, |
Herbert Xu | 36cf9ac | 2007-11-13 21:40:52 -0800 | [diff] [blame] | 100 | .output = xfrm4_prepare_output, |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 101 | .owner = THIS_MODULE, |
| 102 | .encap = XFRM_MODE_TUNNEL, |
Herbert Xu | 1bfcb10 | 2007-10-17 21:31:50 -0700 | [diff] [blame] | 103 | .flags = XFRM_MODE_FLAG_TUNNEL, |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 104 | }; |
| 105 | |
Herbert Xu | 195ad6a | 2007-12-20 13:53:40 -0800 | [diff] [blame] | 106 | static int __init xfrm4_mode_tunnel_init(void) |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 107 | { |
| 108 | return xfrm_register_mode(&xfrm4_tunnel_mode, AF_INET); |
| 109 | } |
| 110 | |
Herbert Xu | 195ad6a | 2007-12-20 13:53:40 -0800 | [diff] [blame] | 111 | static void __exit xfrm4_mode_tunnel_exit(void) |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 112 | { |
| 113 | int err; |
| 114 | |
| 115 | err = xfrm_unregister_mode(&xfrm4_tunnel_mode, AF_INET); |
| 116 | BUG_ON(err); |
| 117 | } |
| 118 | |
Herbert Xu | 195ad6a | 2007-12-20 13:53:40 -0800 | [diff] [blame] | 119 | module_init(xfrm4_mode_tunnel_init); |
| 120 | module_exit(xfrm4_mode_tunnel_exit); |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 121 | MODULE_LICENSE("GPL"); |
| 122 | MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_TUNNEL); |