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 | |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 7 | #include <linux/gfp.h> |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 8 | #include <linux/init.h> |
| 9 | #include <linux/kernel.h> |
| 10 | #include <linux/module.h> |
| 11 | #include <linux/skbuff.h> |
| 12 | #include <linux/stringify.h> |
| 13 | #include <net/dst.h> |
| 14 | #include <net/inet_ecn.h> |
| 15 | #include <net/ip.h> |
| 16 | #include <net/xfrm.h> |
| 17 | |
Saurabh | eb8637c | 2012-07-17 09:44:49 +0000 | [diff] [blame] | 18 | /* Informational hook. The decap is still done here. */ |
| 19 | static struct xfrm_tunnel __rcu *rcv_notify_handlers __read_mostly; |
| 20 | static DEFINE_MUTEX(xfrm4_mode_tunnel_input_mutex); |
| 21 | |
| 22 | int xfrm4_mode_tunnel_input_register(struct xfrm_tunnel *handler) |
| 23 | { |
| 24 | struct xfrm_tunnel __rcu **pprev; |
| 25 | struct xfrm_tunnel *t; |
| 26 | int ret = -EEXIST; |
| 27 | int priority = handler->priority; |
| 28 | |
| 29 | mutex_lock(&xfrm4_mode_tunnel_input_mutex); |
| 30 | |
| 31 | for (pprev = &rcv_notify_handlers; |
| 32 | (t = rcu_dereference_protected(*pprev, |
| 33 | lockdep_is_held(&xfrm4_mode_tunnel_input_mutex))) != NULL; |
| 34 | pprev = &t->next) { |
| 35 | if (t->priority > priority) |
| 36 | break; |
| 37 | if (t->priority == priority) |
| 38 | goto err; |
| 39 | |
| 40 | } |
| 41 | |
| 42 | handler->next = *pprev; |
| 43 | rcu_assign_pointer(*pprev, handler); |
| 44 | |
| 45 | ret = 0; |
| 46 | |
| 47 | err: |
| 48 | mutex_unlock(&xfrm4_mode_tunnel_input_mutex); |
| 49 | return ret; |
| 50 | } |
| 51 | EXPORT_SYMBOL_GPL(xfrm4_mode_tunnel_input_register); |
| 52 | |
| 53 | int xfrm4_mode_tunnel_input_deregister(struct xfrm_tunnel *handler) |
| 54 | { |
| 55 | struct xfrm_tunnel __rcu **pprev; |
| 56 | struct xfrm_tunnel *t; |
| 57 | int ret = -ENOENT; |
| 58 | |
| 59 | mutex_lock(&xfrm4_mode_tunnel_input_mutex); |
| 60 | for (pprev = &rcv_notify_handlers; |
| 61 | (t = rcu_dereference_protected(*pprev, |
| 62 | lockdep_is_held(&xfrm4_mode_tunnel_input_mutex))) != NULL; |
| 63 | pprev = &t->next) { |
| 64 | if (t == handler) { |
| 65 | *pprev = handler->next; |
| 66 | ret = 0; |
| 67 | break; |
| 68 | } |
| 69 | } |
| 70 | mutex_unlock(&xfrm4_mode_tunnel_input_mutex); |
| 71 | synchronize_net(); |
| 72 | |
| 73 | return ret; |
| 74 | } |
| 75 | EXPORT_SYMBOL_GPL(xfrm4_mode_tunnel_input_deregister); |
| 76 | |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 77 | static inline void ipip_ecn_decapsulate(struct sk_buff *skb) |
| 78 | { |
Arnaldo Carvalho de Melo | b0061ce | 2007-04-25 18:02:22 -0700 | [diff] [blame] | 79 | struct iphdr *inner_iph = ipip_hdr(skb); |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 80 | |
Herbert Xu | 227620e | 2007-11-13 21:41:28 -0800 | [diff] [blame] | 81 | if (INET_ECN_is_ce(XFRM_MODE_SKB_CB(skb)->tos)) |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 82 | IP_ECN_set_ce(inner_iph); |
| 83 | } |
| 84 | |
| 85 | /* Add encapsulation header. |
| 86 | * |
Herbert Xu | ceb1eec8 | 2007-10-10 15:45:52 -0700 | [diff] [blame] | 87 | * The top IP header will be constructed per RFC 2401. |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 88 | */ |
Herbert Xu | 195ad6a | 2007-12-20 13:53:40 -0800 | [diff] [blame] | 89 | 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] | 90 | { |
Eric Dumazet | adf3090 | 2009-06-02 05:19:30 +0000 | [diff] [blame] | 91 | struct dst_entry *dst = skb_dst(skb); |
Herbert Xu | 36cf9ac | 2007-11-13 21:40:52 -0800 | [diff] [blame] | 92 | struct iphdr *top_iph; |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 93 | int flags; |
| 94 | |
Herbert Xu | 7b277b1 | 2007-10-10 15:44:06 -0700 | [diff] [blame] | 95 | skb_set_network_header(skb, -x->props.header_len); |
Herbert Xu | 37fedd3 | 2007-10-10 15:44:44 -0700 | [diff] [blame] | 96 | skb->mac_header = skb->network_header + |
| 97 | offsetof(struct iphdr, protocol); |
Herbert Xu | 36cf9ac | 2007-11-13 21:40:52 -0800 | [diff] [blame] | 98 | skb->transport_header = skb->network_header + sizeof(*top_iph); |
Arnaldo Carvalho de Melo | eddc9ec | 2007-04-20 22:47:35 -0700 | [diff] [blame] | 99 | top_iph = ip_hdr(skb); |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 100 | |
| 101 | top_iph->ihl = 5; |
| 102 | top_iph->version = 4; |
| 103 | |
Eric Dumazet | adf3090 | 2009-06-02 05:19:30 +0000 | [diff] [blame] | 104 | top_iph->protocol = xfrm_af2proto(skb_dst(skb)->ops->family); |
Miika Komu | c82f963 | 2007-02-06 14:27:02 -0800 | [diff] [blame] | 105 | |
Nicolas Dichtel | a947b0a | 2013-02-22 10:54:54 +0100 | [diff] [blame] | 106 | /* DS disclosing depends on XFRM_SA_XFLAG_DONT_ENCAP_DSCP */ |
| 107 | if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP) |
| 108 | top_iph->tos = 0; |
| 109 | else |
| 110 | top_iph->tos = XFRM_MODE_SKB_CB(skb)->tos; |
| 111 | top_iph->tos = INET_ECN_encapsulate(top_iph->tos, |
Herbert Xu | 36cf9ac | 2007-11-13 21:40:52 -0800 | [diff] [blame] | 112 | XFRM_MODE_SKB_CB(skb)->tos); |
Miika Komu | c82f963 | 2007-02-06 14:27:02 -0800 | [diff] [blame] | 113 | |
Herbert Xu | 36cf9ac | 2007-11-13 21:40:52 -0800 | [diff] [blame] | 114 | flags = x->props.flags; |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 115 | if (flags & XFRM_STATE_NOECN) |
| 116 | IP_ECN_clear(top_iph); |
| 117 | |
Herbert Xu | 36cf9ac | 2007-11-13 21:40:52 -0800 | [diff] [blame] | 118 | top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) ? |
Steffen Klassert | fe833fc | 2008-06-17 16:37:13 -0700 | [diff] [blame] | 119 | 0 : (XFRM_MODE_SKB_CB(skb)->frag_off & htons(IP_DF)); |
Ansis Atteka | 703133d | 2013-09-18 15:29:53 -0700 | [diff] [blame] | 120 | ip_select_ident(skb, dst->child, NULL); |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 121 | |
David S. Miller | 323e126 | 2010-12-12 21:55:08 -0800 | [diff] [blame] | 122 | top_iph->ttl = ip4_dst_hoplimit(dst->child); |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 123 | |
| 124 | top_iph->saddr = x->props.saddr.a4; |
| 125 | top_iph->daddr = x->id.daddr.a4; |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 126 | |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 127 | return 0; |
| 128 | } |
| 129 | |
Saurabh | eb8637c | 2012-07-17 09:44:49 +0000 | [diff] [blame] | 130 | #define for_each_input_rcu(head, handler) \ |
| 131 | for (handler = rcu_dereference(head); \ |
| 132 | handler != NULL; \ |
| 133 | handler = rcu_dereference(handler->next)) |
| 134 | |
Herbert Xu | 195ad6a | 2007-12-20 13:53:40 -0800 | [diff] [blame] | 135 | 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] | 136 | { |
Saurabh | eb8637c | 2012-07-17 09:44:49 +0000 | [diff] [blame] | 137 | struct xfrm_tunnel *handler; |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 138 | int err = -EINVAL; |
| 139 | |
Herbert Xu | 227620e | 2007-11-13 21:41:28 -0800 | [diff] [blame] | 140 | if (XFRM_MODE_SKB_CB(skb)->protocol != IPPROTO_IPIP) |
| 141 | goto out; |
Miika Komu | c82f963 | 2007-02-06 14:27:02 -0800 | [diff] [blame] | 142 | |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 143 | if (!pskb_may_pull(skb, sizeof(struct iphdr))) |
| 144 | goto out; |
| 145 | |
Saurabh | eb8637c | 2012-07-17 09:44:49 +0000 | [diff] [blame] | 146 | for_each_input_rcu(rcv_notify_handlers, handler) |
| 147 | handler->handler(skb); |
| 148 | |
stephen hemminger | 9aac22d | 2013-02-16 07:40:29 +0000 | [diff] [blame] | 149 | err = skb_unclone(skb, GFP_ATOMIC); |
| 150 | if (err) |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 151 | goto out; |
| 152 | |
Herbert Xu | 227620e | 2007-11-13 21:41:28 -0800 | [diff] [blame] | 153 | if (x->props.flags & XFRM_STATE_DECAP_DSCP) |
| 154 | ipv4_copy_dscp(XFRM_MODE_SKB_CB(skb)->tos, ipip_hdr(skb)); |
| 155 | if (!(x->props.flags & XFRM_STATE_NOECN)) |
| 156 | ipip_ecn_decapsulate(skb); |
| 157 | |
Arnaldo Carvalho de Melo | c1d2bbe | 2007-04-10 20:45:18 -0700 | [diff] [blame] | 158 | skb_reset_network_header(skb); |
Eric Dumazet | 0360689 | 2012-02-23 10:55:02 +0000 | [diff] [blame] | 159 | skb_mac_header_rebuild(skb); |
| 160 | |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 161 | err = 0; |
| 162 | |
| 163 | out: |
| 164 | return err; |
| 165 | } |
| 166 | |
| 167 | static struct xfrm_mode xfrm4_tunnel_mode = { |
Herbert Xu | 195ad6a | 2007-12-20 13:53:40 -0800 | [diff] [blame] | 168 | .input2 = xfrm4_mode_tunnel_input, |
Herbert Xu | 227620e | 2007-11-13 21:41:28 -0800 | [diff] [blame] | 169 | .input = xfrm_prepare_input, |
Herbert Xu | 195ad6a | 2007-12-20 13:53:40 -0800 | [diff] [blame] | 170 | .output2 = xfrm4_mode_tunnel_output, |
Herbert Xu | 36cf9ac | 2007-11-13 21:40:52 -0800 | [diff] [blame] | 171 | .output = xfrm4_prepare_output, |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 172 | .owner = THIS_MODULE, |
| 173 | .encap = XFRM_MODE_TUNNEL, |
Herbert Xu | 1bfcb10 | 2007-10-17 21:31:50 -0700 | [diff] [blame] | 174 | .flags = XFRM_MODE_FLAG_TUNNEL, |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 175 | }; |
| 176 | |
Herbert Xu | 195ad6a | 2007-12-20 13:53:40 -0800 | [diff] [blame] | 177 | static int __init xfrm4_mode_tunnel_init(void) |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 178 | { |
| 179 | return xfrm_register_mode(&xfrm4_tunnel_mode, AF_INET); |
| 180 | } |
| 181 | |
Herbert Xu | 195ad6a | 2007-12-20 13:53:40 -0800 | [diff] [blame] | 182 | static void __exit xfrm4_mode_tunnel_exit(void) |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 183 | { |
| 184 | int err; |
| 185 | |
| 186 | err = xfrm_unregister_mode(&xfrm4_tunnel_mode, AF_INET); |
| 187 | BUG_ON(err); |
| 188 | } |
| 189 | |
Herbert Xu | 195ad6a | 2007-12-20 13:53:40 -0800 | [diff] [blame] | 190 | module_init(xfrm4_mode_tunnel_init); |
| 191 | module_exit(xfrm4_mode_tunnel_exit); |
Herbert Xu | b59f45d | 2006-05-27 23:05:54 -0700 | [diff] [blame] | 192 | MODULE_LICENSE("GPL"); |
| 193 | MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_TUNNEL); |