Commit | Line | Data |
---|---|---|
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 | ||
6067b2ba | 19 | static int xfrm4_parse_spi(struct sk_buff *skb, u8 nexthdr, __be32 *spi, __be32 *seq) |
1da177e4 LT |
20 | { |
21 | switch (nexthdr) { | |
22 | case IPPROTO_IPIP: | |
c0d56408 | 23 | case IPPROTO_IPV6: |
eddc9ec5 | 24 | *spi = ip_hdr(skb)->saddr; |
1da177e4 LT |
25 | *seq = 0; |
26 | return 0; | |
27 | } | |
28 | ||
29 | return xfrm_parse_spi(skb, nexthdr, spi, seq); | |
30 | } | |
31 | ||
b05e1066 PM |
32 | #ifdef CONFIG_NETFILTER |
33 | static inline int xfrm4_rcv_encap_finish(struct sk_buff *skb) | |
34 | { | |
b05e1066 | 35 | if (skb->dst == NULL) { |
eddc9ec5 ACM |
36 | const struct iphdr *iph = ip_hdr(skb); |
37 | ||
b05e1066 | 38 | if (ip_route_input(skb, iph->daddr, iph->saddr, iph->tos, |
e905a9ed | 39 | skb->dev)) |
b05e1066 PM |
40 | goto drop; |
41 | } | |
42 | return dst_input(skb); | |
43 | drop: | |
44 | kfree_skb(skb); | |
45 | return NET_RX_DROP; | |
46 | } | |
47 | #endif | |
48 | ||
067b207b | 49 | static int xfrm4_rcv_encap(struct sk_buff *skb, __u16 encap_type) |
1da177e4 | 50 | { |
6067b2ba | 51 | __be32 spi, seq; |
dbe5b4aa | 52 | struct xfrm_state *xfrm_vec[XFRM_MAX_DEPTH]; |
1da177e4 LT |
53 | struct xfrm_state *x; |
54 | int xfrm_nr = 0; | |
55 | int decaps = 0; | |
eddc9ec5 | 56 | int err = xfrm4_parse_spi(skb, ip_hdr(skb)->protocol, &spi, &seq); |
631a6698 | 57 | unsigned int nhoff = offsetof(struct iphdr, protocol); |
1da177e4 | 58 | |
eddc9ec5 | 59 | if (err != 0) |
1da177e4 LT |
60 | goto drop; |
61 | ||
62 | do { | |
eddc9ec5 | 63 | const struct iphdr *iph = ip_hdr(skb); |
631a6698 | 64 | int nexthdr; |
1da177e4 LT |
65 | |
66 | if (xfrm_nr == XFRM_MAX_DEPTH) | |
67 | goto drop; | |
68 | ||
c0d56408 KM |
69 | x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, |
70 | iph->protocol != IPPROTO_IPV6 ? iph->protocol : IPPROTO_IPIP, AF_INET); | |
1da177e4 LT |
71 | if (x == NULL) |
72 | goto drop; | |
73 | ||
74 | spin_lock(&x->lock); | |
75 | if (unlikely(x->km.state != XFRM_STATE_VALID)) | |
76 | goto drop_unlock; | |
77 | ||
8bf4b8a1 | 78 | if ((x->encap ? x->encap->encap_type : 0) != encap_type) |
e695633e HX |
79 | goto drop_unlock; |
80 | ||
1da177e4 LT |
81 | if (x->props.replay_window && xfrm_replay_check(x, seq)) |
82 | goto drop_unlock; | |
83 | ||
84 | if (xfrm_state_check_expire(x)) | |
85 | goto drop_unlock; | |
86 | ||
631a6698 HX |
87 | nexthdr = x->type->input(x, skb); |
88 | if (nexthdr <= 0) | |
1da177e4 LT |
89 | goto drop_unlock; |
90 | ||
631a6698 HX |
91 | skb_network_header(skb)[nhoff] = nexthdr; |
92 | ||
1da177e4 LT |
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 | ||
eddc9ec5 ACM |
114 | err = xfrm_parse_spi(skb, ip_hdr(skb)->protocol, &spi, &seq); |
115 | if (err < 0) | |
1da177e4 LT |
116 | goto drop; |
117 | } while (!err); | |
118 | ||
119 | /* Allocate new secpath or COW existing one. */ | |
120 | ||
121 | if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) { | |
122 | struct sec_path *sp; | |
123 | sp = secpath_dup(skb->sp); | |
124 | if (!sp) | |
125 | goto drop; | |
126 | if (skb->sp) | |
127 | secpath_put(skb->sp); | |
128 | skb->sp = sp; | |
129 | } | |
130 | if (xfrm_nr + skb->sp->len > XFRM_MAX_DEPTH) | |
131 | goto drop; | |
132 | ||
dbe5b4aa HX |
133 | memcpy(skb->sp->xvec + skb->sp->len, xfrm_vec, |
134 | xfrm_nr * sizeof(xfrm_vec[0])); | |
1da177e4 LT |
135 | skb->sp->len += xfrm_nr; |
136 | ||
b05e1066 PM |
137 | nf_reset(skb); |
138 | ||
1da177e4 | 139 | if (decaps) { |
f282d45c KM |
140 | dst_release(skb->dst); |
141 | skb->dst = NULL; | |
1da177e4 LT |
142 | netif_rx(skb); |
143 | return 0; | |
144 | } else { | |
b05e1066 | 145 | #ifdef CONFIG_NETFILTER |
d56f90a7 | 146 | __skb_push(skb, skb->data - skb_network_header(skb)); |
eddc9ec5 ACM |
147 | ip_hdr(skb)->tot_len = htons(skb->len); |
148 | ip_send_check(ip_hdr(skb)); | |
b05e1066 PM |
149 | |
150 | NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, skb->dev, NULL, | |
e905a9ed | 151 | xfrm4_rcv_encap_finish); |
b05e1066 PM |
152 | return 0; |
153 | #else | |
eddc9ec5 | 154 | return -ip_hdr(skb)->protocol; |
b05e1066 | 155 | #endif |
1da177e4 LT |
156 | } |
157 | ||
158 | drop_unlock: | |
159 | spin_unlock(&x->lock); | |
160 | xfrm_state_put(x); | |
161 | drop: | |
162 | while (--xfrm_nr >= 0) | |
dbe5b4aa | 163 | xfrm_state_put(xfrm_vec[xfrm_nr]); |
1da177e4 LT |
164 | |
165 | kfree_skb(skb); | |
166 | return 0; | |
167 | } | |
067b207b JC |
168 | |
169 | /* If it's a keepalive packet, then just eat it. | |
170 | * If it's an encapsulated packet, then pass it to the | |
171 | * IPsec xfrm input. | |
172 | * Returns 0 if skb passed to xfrm or was dropped. | |
173 | * Returns >0 if skb should be passed to UDP. | |
174 | * Returns <0 if skb should be resubmitted (-ret is protocol) | |
175 | */ | |
176 | int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb) | |
177 | { | |
178 | struct udp_sock *up = udp_sk(sk); | |
179 | struct udphdr *uh; | |
180 | struct iphdr *iph; | |
181 | int iphlen, len; | |
182 | int ret; | |
183 | ||
184 | __u8 *udpdata; | |
185 | __be32 *udpdata32; | |
186 | __u16 encap_type = up->encap_type; | |
187 | ||
188 | /* if this is not encapsulated socket, then just return now */ | |
189 | if (!encap_type) | |
190 | return 1; | |
191 | ||
192 | /* If this is a paged skb, make sure we pull up | |
193 | * whatever data we need to look at. */ | |
194 | len = skb->len - sizeof(struct udphdr); | |
195 | if (!pskb_may_pull(skb, sizeof(struct udphdr) + min(len, 8))) | |
196 | return 1; | |
197 | ||
198 | /* Now we can get the pointers */ | |
199 | uh = udp_hdr(skb); | |
200 | udpdata = (__u8 *)uh + sizeof(struct udphdr); | |
201 | udpdata32 = (__be32 *)udpdata; | |
202 | ||
203 | switch (encap_type) { | |
204 | default: | |
205 | case UDP_ENCAP_ESPINUDP: | |
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 > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) { | |
210 | /* ESP Packet without Non-ESP header */ | |
211 | len = sizeof(struct udphdr); | |
212 | } else | |
213 | /* Must be an IKE packet.. pass it through */ | |
214 | return 1; | |
215 | break; | |
216 | case UDP_ENCAP_ESPINUDP_NON_IKE: | |
217 | /* Check if this is a keepalive packet. If so, eat it. */ | |
218 | if (len == 1 && udpdata[0] == 0xff) { | |
219 | goto drop; | |
220 | } else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) && | |
221 | udpdata32[0] == 0 && udpdata32[1] == 0) { | |
222 | ||
223 | /* ESP Packet with Non-IKE marker */ | |
224 | len = sizeof(struct udphdr) + 2 * sizeof(u32); | |
225 | } else | |
226 | /* Must be an IKE packet.. pass it through */ | |
227 | return 1; | |
228 | break; | |
229 | } | |
230 | ||
231 | /* At this point we are sure that this is an ESPinUDP packet, | |
232 | * so we need to remove 'len' bytes from the packet (the UDP | |
233 | * header and optional ESP marker bytes) and then modify the | |
234 | * protocol to ESP, and then call into the transform receiver. | |
235 | */ | |
236 | if (skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) | |
237 | goto drop; | |
238 | ||
239 | /* Now we can update and verify the packet length... */ | |
240 | iph = ip_hdr(skb); | |
241 | iphlen = iph->ihl << 2; | |
242 | iph->tot_len = htons(ntohs(iph->tot_len) - len); | |
243 | if (skb->len < iphlen + len) { | |
244 | /* packet is too small!?! */ | |
245 | goto drop; | |
246 | } | |
247 | ||
248 | /* pull the data buffer up to the ESP header and set the | |
249 | * transport header to point to ESP. Keep UDP on the stack | |
250 | * for later. | |
251 | */ | |
252 | __skb_pull(skb, len); | |
253 | skb_reset_transport_header(skb); | |
254 | ||
255 | /* modify the protocol (it's ESP!) */ | |
256 | iph->protocol = IPPROTO_ESP; | |
257 | ||
258 | /* process ESP */ | |
259 | ret = xfrm4_rcv_encap(skb, encap_type); | |
260 | return ret; | |
261 | ||
262 | drop: | |
263 | kfree_skb(skb); | |
264 | return 0; | |
265 | } | |
266 | ||
267 | int xfrm4_rcv(struct sk_buff *skb) | |
268 | { | |
269 | return xfrm4_rcv_encap(skb, 0); | |
270 | } | |
271 | ||
272 | EXPORT_SYMBOL(xfrm4_rcv); |