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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 | ||
b05e1066 PM |
19 | #ifdef CONFIG_NETFILTER |
20 | static inline int xfrm4_rcv_encap_finish(struct sk_buff *skb) | |
21 | { | |
b05e1066 | 22 | if (skb->dst == NULL) { |
eddc9ec5 ACM |
23 | const struct iphdr *iph = ip_hdr(skb); |
24 | ||
b05e1066 | 25 | if (ip_route_input(skb, iph->daddr, iph->saddr, iph->tos, |
e905a9ed | 26 | skb->dev)) |
b05e1066 PM |
27 | goto drop; |
28 | } | |
29 | return dst_input(skb); | |
30 | drop: | |
31 | kfree_skb(skb); | |
32 | return NET_RX_DROP; | |
33 | } | |
34 | #endif | |
35 | ||
c4541b41 HX |
36 | int xfrm4_rcv_encap(struct sk_buff *skb, int nexthdr, __be32 spi, |
37 | int encap_type) | |
1da177e4 | 38 | { |
c4541b41 HX |
39 | int err; |
40 | __be32 seq; | |
dbe5b4aa | 41 | struct xfrm_state *xfrm_vec[XFRM_MAX_DEPTH]; |
1da177e4 LT |
42 | struct xfrm_state *x; |
43 | int xfrm_nr = 0; | |
44 | int decaps = 0; | |
631a6698 | 45 | unsigned int nhoff = offsetof(struct iphdr, protocol); |
1da177e4 | 46 | |
c4541b41 HX |
47 | seq = 0; |
48 | if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0) | |
1da177e4 LT |
49 | goto drop; |
50 | ||
51 | do { | |
eddc9ec5 | 52 | const struct iphdr *iph = ip_hdr(skb); |
1da177e4 LT |
53 | |
54 | if (xfrm_nr == XFRM_MAX_DEPTH) | |
55 | goto drop; | |
56 | ||
c0d56408 | 57 | x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, |
c4541b41 | 58 | nexthdr, AF_INET); |
1da177e4 LT |
59 | if (x == NULL) |
60 | goto drop; | |
61 | ||
62 | spin_lock(&x->lock); | |
63 | if (unlikely(x->km.state != XFRM_STATE_VALID)) | |
64 | goto drop_unlock; | |
65 | ||
8bf4b8a1 | 66 | if ((x->encap ? x->encap->encap_type : 0) != encap_type) |
e695633e HX |
67 | goto drop_unlock; |
68 | ||
1da177e4 LT |
69 | if (x->props.replay_window && xfrm_replay_check(x, seq)) |
70 | goto drop_unlock; | |
71 | ||
72 | if (xfrm_state_check_expire(x)) | |
73 | goto drop_unlock; | |
74 | ||
631a6698 HX |
75 | nexthdr = x->type->input(x, skb); |
76 | if (nexthdr <= 0) | |
1da177e4 LT |
77 | goto drop_unlock; |
78 | ||
631a6698 HX |
79 | skb_network_header(skb)[nhoff] = nexthdr; |
80 | ||
1da177e4 LT |
81 | /* only the first xfrm gets the encap type */ |
82 | encap_type = 0; | |
83 | ||
84 | if (x->props.replay_window) | |
85 | xfrm_replay_advance(x, seq); | |
86 | ||
87 | x->curlft.bytes += skb->len; | |
88 | x->curlft.packets++; | |
89 | ||
90 | spin_unlock(&x->lock); | |
91 | ||
dbe5b4aa | 92 | xfrm_vec[xfrm_nr++] = x; |
1da177e4 | 93 | |
b59f45d0 HX |
94 | if (x->mode->input(x, skb)) |
95 | goto drop; | |
1da177e4 | 96 | |
1bfcb10f | 97 | if (x->mode->flags & XFRM_MODE_FLAG_TUNNEL) { |
1da177e4 LT |
98 | decaps = 1; |
99 | break; | |
100 | } | |
101 | ||
c4541b41 | 102 | err = xfrm_parse_spi(skb, nexthdr, &spi, &seq); |
eddc9ec5 | 103 | if (err < 0) |
1da177e4 LT |
104 | goto drop; |
105 | } while (!err); | |
106 | ||
107 | /* Allocate new secpath or COW existing one. */ | |
108 | ||
109 | if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) { | |
110 | struct sec_path *sp; | |
111 | sp = secpath_dup(skb->sp); | |
112 | if (!sp) | |
113 | goto drop; | |
114 | if (skb->sp) | |
115 | secpath_put(skb->sp); | |
116 | skb->sp = sp; | |
117 | } | |
118 | if (xfrm_nr + skb->sp->len > XFRM_MAX_DEPTH) | |
119 | goto drop; | |
120 | ||
dbe5b4aa HX |
121 | memcpy(skb->sp->xvec + skb->sp->len, xfrm_vec, |
122 | xfrm_nr * sizeof(xfrm_vec[0])); | |
1da177e4 LT |
123 | skb->sp->len += xfrm_nr; |
124 | ||
b05e1066 PM |
125 | nf_reset(skb); |
126 | ||
1da177e4 | 127 | if (decaps) { |
f282d45c KM |
128 | dst_release(skb->dst); |
129 | skb->dst = NULL; | |
1da177e4 LT |
130 | netif_rx(skb); |
131 | return 0; | |
132 | } else { | |
b05e1066 | 133 | #ifdef CONFIG_NETFILTER |
d56f90a7 | 134 | __skb_push(skb, skb->data - skb_network_header(skb)); |
eddc9ec5 ACM |
135 | ip_hdr(skb)->tot_len = htons(skb->len); |
136 | ip_send_check(ip_hdr(skb)); | |
b05e1066 PM |
137 | |
138 | NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, skb->dev, NULL, | |
e905a9ed | 139 | xfrm4_rcv_encap_finish); |
b05e1066 PM |
140 | return 0; |
141 | #else | |
eddc9ec5 | 142 | return -ip_hdr(skb)->protocol; |
b05e1066 | 143 | #endif |
1da177e4 LT |
144 | } |
145 | ||
146 | drop_unlock: | |
147 | spin_unlock(&x->lock); | |
148 | xfrm_state_put(x); | |
149 | drop: | |
150 | while (--xfrm_nr >= 0) | |
dbe5b4aa | 151 | xfrm_state_put(xfrm_vec[xfrm_nr]); |
1da177e4 LT |
152 | |
153 | kfree_skb(skb); | |
154 | return 0; | |
155 | } | |
c4541b41 | 156 | EXPORT_SYMBOL(xfrm4_rcv_encap); |
067b207b JC |
157 | |
158 | /* If it's a keepalive packet, then just eat it. | |
159 | * If it's an encapsulated packet, then pass it to the | |
160 | * IPsec xfrm input. | |
161 | * Returns 0 if skb passed to xfrm or was dropped. | |
162 | * Returns >0 if skb should be passed to UDP. | |
163 | * Returns <0 if skb should be resubmitted (-ret is protocol) | |
164 | */ | |
165 | int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb) | |
166 | { | |
167 | struct udp_sock *up = udp_sk(sk); | |
168 | struct udphdr *uh; | |
169 | struct iphdr *iph; | |
170 | int iphlen, len; | |
171 | int ret; | |
172 | ||
173 | __u8 *udpdata; | |
174 | __be32 *udpdata32; | |
175 | __u16 encap_type = up->encap_type; | |
176 | ||
177 | /* if this is not encapsulated socket, then just return now */ | |
178 | if (!encap_type) | |
179 | return 1; | |
180 | ||
181 | /* If this is a paged skb, make sure we pull up | |
182 | * whatever data we need to look at. */ | |
183 | len = skb->len - sizeof(struct udphdr); | |
184 | if (!pskb_may_pull(skb, sizeof(struct udphdr) + min(len, 8))) | |
185 | return 1; | |
186 | ||
187 | /* Now we can get the pointers */ | |
188 | uh = udp_hdr(skb); | |
189 | udpdata = (__u8 *)uh + sizeof(struct udphdr); | |
190 | udpdata32 = (__be32 *)udpdata; | |
191 | ||
192 | switch (encap_type) { | |
193 | default: | |
194 | case UDP_ENCAP_ESPINUDP: | |
195 | /* Check if this is a keepalive packet. If so, eat it. */ | |
196 | if (len == 1 && udpdata[0] == 0xff) { | |
197 | goto drop; | |
198 | } else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) { | |
199 | /* ESP Packet without Non-ESP header */ | |
200 | len = sizeof(struct udphdr); | |
201 | } else | |
202 | /* Must be an IKE packet.. pass it through */ | |
203 | return 1; | |
204 | break; | |
205 | case UDP_ENCAP_ESPINUDP_NON_IKE: | |
206 | /* Check if this is a keepalive packet. If so, eat it. */ | |
207 | if (len == 1 && udpdata[0] == 0xff) { | |
208 | goto drop; | |
209 | } else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) && | |
210 | udpdata32[0] == 0 && udpdata32[1] == 0) { | |
211 | ||
212 | /* ESP Packet with Non-IKE marker */ | |
213 | len = sizeof(struct udphdr) + 2 * sizeof(u32); | |
214 | } else | |
215 | /* Must be an IKE packet.. pass it through */ | |
216 | return 1; | |
217 | break; | |
218 | } | |
219 | ||
220 | /* At this point we are sure that this is an ESPinUDP packet, | |
221 | * so we need to remove 'len' bytes from the packet (the UDP | |
222 | * header and optional ESP marker bytes) and then modify the | |
223 | * protocol to ESP, and then call into the transform receiver. | |
224 | */ | |
225 | if (skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) | |
226 | goto drop; | |
227 | ||
228 | /* Now we can update and verify the packet length... */ | |
229 | iph = ip_hdr(skb); | |
230 | iphlen = iph->ihl << 2; | |
231 | iph->tot_len = htons(ntohs(iph->tot_len) - len); | |
232 | if (skb->len < iphlen + len) { | |
233 | /* packet is too small!?! */ | |
234 | goto drop; | |
235 | } | |
236 | ||
237 | /* pull the data buffer up to the ESP header and set the | |
238 | * transport header to point to ESP. Keep UDP on the stack | |
239 | * for later. | |
240 | */ | |
241 | __skb_pull(skb, len); | |
242 | skb_reset_transport_header(skb); | |
243 | ||
067b207b | 244 | /* process ESP */ |
c4541b41 | 245 | ret = xfrm4_rcv_encap(skb, IPPROTO_ESP, 0, encap_type); |
067b207b JC |
246 | return ret; |
247 | ||
248 | drop: | |
249 | kfree_skb(skb); | |
250 | return 0; | |
251 | } | |
252 | ||
253 | int xfrm4_rcv(struct sk_buff *skb) | |
254 | { | |
c4541b41 | 255 | return xfrm4_rcv_spi(skb, ip_hdr(skb)->protocol, 0); |
067b207b JC |
256 | } |
257 | ||
258 | EXPORT_SYMBOL(xfrm4_rcv); |