blob: 850d919591d1c817bc196407a90fd338ab0d2316 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
9 *
10 */
11
12#include <linux/module.h>
13#include <linux/string.h>
Patrick McHardyb05e1062006-01-06 23:03:34 -080014#include <linux/netfilter.h>
15#include <linux/netfilter_ipv4.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <net/inet_ecn.h>
17#include <net/ip.h>
18#include <net/xfrm.h>
19
20int xfrm4_rcv(struct sk_buff *skb)
21{
22 return xfrm4_rcv_encap(skb, 0);
23}
24
25EXPORT_SYMBOL(xfrm4_rcv);
26
27static inline void ipip_ecn_decapsulate(struct sk_buff *skb)
28{
29 struct iphdr *outer_iph = skb->nh.iph;
30 struct iphdr *inner_iph = skb->h.ipiph;
31
32 if (INET_ECN_is_ce(outer_iph->tos))
33 IP_ECN_set_ce(inner_iph);
34}
35
36static int xfrm4_parse_spi(struct sk_buff *skb, u8 nexthdr, u32 *spi, u32 *seq)
37{
38 switch (nexthdr) {
39 case IPPROTO_IPIP:
40 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
41 return -EINVAL;
42 *spi = skb->nh.iph->saddr;
43 *seq = 0;
44 return 0;
45 }
46
47 return xfrm_parse_spi(skb, nexthdr, spi, seq);
48}
49
Patrick McHardyb05e1062006-01-06 23:03:34 -080050#ifdef CONFIG_NETFILTER
51static inline int xfrm4_rcv_encap_finish(struct sk_buff *skb)
52{
53 struct iphdr *iph = skb->nh.iph;
54
55 if (skb->dst == NULL) {
56 if (ip_route_input(skb, iph->daddr, iph->saddr, iph->tos,
57 skb->dev))
58 goto drop;
59 }
60 return dst_input(skb);
61drop:
62 kfree_skb(skb);
63 return NET_RX_DROP;
64}
65#endif
66
Linus Torvalds1da177e2005-04-16 15:20:36 -070067int xfrm4_rcv_encap(struct sk_buff *skb, __u16 encap_type)
68{
69 int err;
70 u32 spi, seq;
71 struct sec_decap_state xfrm_vec[XFRM_MAX_DEPTH];
72 struct xfrm_state *x;
73 int xfrm_nr = 0;
74 int decaps = 0;
75
76 if ((err = xfrm4_parse_spi(skb, skb->nh.iph->protocol, &spi, &seq)) != 0)
77 goto drop;
78
79 do {
80 struct iphdr *iph = skb->nh.iph;
81
82 if (xfrm_nr == XFRM_MAX_DEPTH)
83 goto drop;
84
85 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, iph->protocol, AF_INET);
86 if (x == NULL)
87 goto drop;
88
89 spin_lock(&x->lock);
90 if (unlikely(x->km.state != XFRM_STATE_VALID))
91 goto drop_unlock;
92
93 if (x->props.replay_window && xfrm_replay_check(x, seq))
94 goto drop_unlock;
95
96 if (xfrm_state_check_expire(x))
97 goto drop_unlock;
98
99 xfrm_vec[xfrm_nr].decap.decap_type = encap_type;
100 if (x->type->input(x, &(xfrm_vec[xfrm_nr].decap), skb))
101 goto drop_unlock;
102
103 /* only the first xfrm gets the encap type */
104 encap_type = 0;
105
106 if (x->props.replay_window)
107 xfrm_replay_advance(x, seq);
108
109 x->curlft.bytes += skb->len;
110 x->curlft.packets++;
111
112 spin_unlock(&x->lock);
113
114 xfrm_vec[xfrm_nr++].xvec = x;
115
116 iph = skb->nh.iph;
117
118 if (x->props.mode) {
119 if (iph->protocol != IPPROTO_IPIP)
120 goto drop;
121 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
122 goto drop;
123 if (skb_cloned(skb) &&
124 pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
125 goto drop;
126 if (x->props.flags & XFRM_STATE_DECAP_DSCP)
127 ipv4_copy_dscp(iph, skb->h.ipiph);
128 if (!(x->props.flags & XFRM_STATE_NOECN))
129 ipip_ecn_decapsulate(skb);
130 skb->mac.raw = memmove(skb->data - skb->mac_len,
131 skb->mac.raw, skb->mac_len);
132 skb->nh.raw = skb->data;
133 memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options));
134 decaps = 1;
135 break;
136 }
137
138 if ((err = xfrm_parse_spi(skb, skb->nh.iph->protocol, &spi, &seq)) < 0)
139 goto drop;
140 } while (!err);
141
142 /* Allocate new secpath or COW existing one. */
143
144 if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
145 struct sec_path *sp;
146 sp = secpath_dup(skb->sp);
147 if (!sp)
148 goto drop;
149 if (skb->sp)
150 secpath_put(skb->sp);
151 skb->sp = sp;
152 }
153 if (xfrm_nr + skb->sp->len > XFRM_MAX_DEPTH)
154 goto drop;
155
156 memcpy(skb->sp->x+skb->sp->len, xfrm_vec, xfrm_nr*sizeof(struct sec_decap_state));
157 skb->sp->len += xfrm_nr;
158
Patrick McHardyb05e1062006-01-06 23:03:34 -0800159 nf_reset(skb);
160
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161 if (decaps) {
162 if (!(skb->dev->flags&IFF_LOOPBACK)) {
163 dst_release(skb->dst);
164 skb->dst = NULL;
165 }
166 netif_rx(skb);
167 return 0;
168 } else {
Patrick McHardyb05e1062006-01-06 23:03:34 -0800169#ifdef CONFIG_NETFILTER
170 __skb_push(skb, skb->data - skb->nh.raw);
171 skb->nh.iph->tot_len = htons(skb->len);
172 ip_send_check(skb->nh.iph);
173
174 NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, skb->dev, NULL,
175 xfrm4_rcv_encap_finish);
176 return 0;
177#else
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178 return -skb->nh.iph->protocol;
Patrick McHardyb05e1062006-01-06 23:03:34 -0800179#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180 }
181
182drop_unlock:
183 spin_unlock(&x->lock);
184 xfrm_state_put(x);
185drop:
186 while (--xfrm_nr >= 0)
187 xfrm_state_put(xfrm_vec[xfrm_nr].xvec);
188
189 kfree_skb(skb);
190 return 0;
191}