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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * xfrm4_input.c | |
3 | * | |
4 | * Changes: | |
5 | * YOSHIFUJI Hideaki @USAGI | |
6 | * Split up af-specific portion | |
7 | * Derek Atkins <derek@ihtfp.com> | |
8 | * Add Encapsulation support | |
e905a9ed | 9 | * |
1da177e4 LT |
10 | */ |
11 | ||
12 | #include <linux/module.h> | |
13 | #include <linux/string.h> | |
b05e1066 PM |
14 | #include <linux/netfilter.h> |
15 | #include <linux/netfilter_ipv4.h> | |
1da177e4 LT |
16 | #include <net/ip.h> |
17 | #include <net/xfrm.h> | |
18 | ||
19 | int xfrm4_rcv(struct sk_buff *skb) | |
20 | { | |
21 | return xfrm4_rcv_encap(skb, 0); | |
22 | } | |
23 | ||
24 | EXPORT_SYMBOL(xfrm4_rcv); | |
25 | ||
6067b2ba | 26 | static int xfrm4_parse_spi(struct sk_buff *skb, u8 nexthdr, __be32 *spi, __be32 *seq) |
1da177e4 LT |
27 | { |
28 | switch (nexthdr) { | |
29 | case IPPROTO_IPIP: | |
1da177e4 LT |
30 | *spi = skb->nh.iph->saddr; |
31 | *seq = 0; | |
32 | return 0; | |
33 | } | |
34 | ||
35 | return xfrm_parse_spi(skb, nexthdr, spi, seq); | |
36 | } | |
37 | ||
b05e1066 PM |
38 | #ifdef CONFIG_NETFILTER |
39 | static inline int xfrm4_rcv_encap_finish(struct sk_buff *skb) | |
40 | { | |
41 | struct iphdr *iph = skb->nh.iph; | |
42 | ||
43 | if (skb->dst == NULL) { | |
44 | if (ip_route_input(skb, iph->daddr, iph->saddr, iph->tos, | |
e905a9ed | 45 | skb->dev)) |
b05e1066 PM |
46 | goto drop; |
47 | } | |
48 | return dst_input(skb); | |
49 | drop: | |
50 | kfree_skb(skb); | |
51 | return NET_RX_DROP; | |
52 | } | |
53 | #endif | |
54 | ||
1da177e4 LT |
55 | int xfrm4_rcv_encap(struct sk_buff *skb, __u16 encap_type) |
56 | { | |
57 | int err; | |
6067b2ba | 58 | __be32 spi, seq; |
dbe5b4aa | 59 | struct xfrm_state *xfrm_vec[XFRM_MAX_DEPTH]; |
1da177e4 LT |
60 | struct xfrm_state *x; |
61 | int xfrm_nr = 0; | |
62 | int decaps = 0; | |
63 | ||
64 | if ((err = xfrm4_parse_spi(skb, skb->nh.iph->protocol, &spi, &seq)) != 0) | |
65 | goto drop; | |
66 | ||
67 | do { | |
68 | struct iphdr *iph = skb->nh.iph; | |
69 | ||
70 | if (xfrm_nr == XFRM_MAX_DEPTH) | |
71 | goto drop; | |
72 | ||
73 | x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, iph->protocol, AF_INET); | |
74 | if (x == NULL) | |
75 | goto drop; | |
76 | ||
77 | spin_lock(&x->lock); | |
78 | if (unlikely(x->km.state != XFRM_STATE_VALID)) | |
79 | goto drop_unlock; | |
80 | ||
8bf4b8a1 | 81 | if ((x->encap ? x->encap->encap_type : 0) != encap_type) |
e695633e HX |
82 | goto drop_unlock; |
83 | ||
1da177e4 LT |
84 | if (x->props.replay_window && xfrm_replay_check(x, seq)) |
85 | goto drop_unlock; | |
86 | ||
87 | if (xfrm_state_check_expire(x)) | |
88 | goto drop_unlock; | |
89 | ||
e695633e | 90 | if (x->type->input(x, skb)) |
1da177e4 LT |
91 | goto drop_unlock; |
92 | ||
93 | /* only the first xfrm gets the encap type */ | |
94 | encap_type = 0; | |
95 | ||
96 | if (x->props.replay_window) | |
97 | xfrm_replay_advance(x, seq); | |
98 | ||
99 | x->curlft.bytes += skb->len; | |
100 | x->curlft.packets++; | |
101 | ||
102 | spin_unlock(&x->lock); | |
103 | ||
dbe5b4aa | 104 | xfrm_vec[xfrm_nr++] = x; |
1da177e4 | 105 | |
b59f45d0 HX |
106 | if (x->mode->input(x, skb)) |
107 | goto drop; | |
1da177e4 | 108 | |
7e49e6de | 109 | if (x->props.mode == XFRM_MODE_TUNNEL) { |
1da177e4 LT |
110 | decaps = 1; |
111 | break; | |
112 | } | |
113 | ||
114 | if ((err = xfrm_parse_spi(skb, skb->nh.iph->protocol, &spi, &seq)) < 0) | |
115 | goto drop; | |
116 | } while (!err); | |
117 | ||
118 | /* Allocate new secpath or COW existing one. */ | |
119 | ||
120 | if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) { | |
121 | struct sec_path *sp; | |
122 | sp = secpath_dup(skb->sp); | |
123 | if (!sp) | |
124 | goto drop; | |
125 | if (skb->sp) | |
126 | secpath_put(skb->sp); | |
127 | skb->sp = sp; | |
128 | } | |
129 | if (xfrm_nr + skb->sp->len > XFRM_MAX_DEPTH) | |
130 | goto drop; | |
131 | ||
dbe5b4aa HX |
132 | memcpy(skb->sp->xvec + skb->sp->len, xfrm_vec, |
133 | xfrm_nr * sizeof(xfrm_vec[0])); | |
1da177e4 LT |
134 | skb->sp->len += xfrm_nr; |
135 | ||
b05e1066 PM |
136 | nf_reset(skb); |
137 | ||
1da177e4 LT |
138 | if (decaps) { |
139 | if (!(skb->dev->flags&IFF_LOOPBACK)) { | |
140 | dst_release(skb->dst); | |
141 | skb->dst = NULL; | |
142 | } | |
143 | netif_rx(skb); | |
144 | return 0; | |
145 | } else { | |
b05e1066 PM |
146 | #ifdef CONFIG_NETFILTER |
147 | __skb_push(skb, skb->data - skb->nh.raw); | |
148 | skb->nh.iph->tot_len = htons(skb->len); | |
149 | ip_send_check(skb->nh.iph); | |
150 | ||
151 | NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, skb->dev, NULL, | |
e905a9ed | 152 | xfrm4_rcv_encap_finish); |
b05e1066 PM |
153 | return 0; |
154 | #else | |
1da177e4 | 155 | return -skb->nh.iph->protocol; |
b05e1066 | 156 | #endif |
1da177e4 LT |
157 | } |
158 | ||
159 | drop_unlock: | |
160 | spin_unlock(&x->lock); | |
161 | xfrm_state_put(x); | |
162 | drop: | |
163 | while (--xfrm_nr >= 0) | |
dbe5b4aa | 164 | xfrm_state_put(xfrm_vec[xfrm_nr]); |
1da177e4 LT |
165 | |
166 | kfree_skb(skb); | |
167 | return 0; | |
168 | } |