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 | ||
5a0e3ad6 | 12 | #include <linux/slab.h> |
1da177e4 LT |
13 | #include <linux/module.h> |
14 | #include <linux/string.h> | |
b05e1066 PM |
15 | #include <linux/netfilter.h> |
16 | #include <linux/netfilter_ipv4.h> | |
1da177e4 LT |
17 | #include <net/ip.h> |
18 | #include <net/xfrm.h> | |
19 | ||
227620e2 HX |
20 | int xfrm4_extract_input(struct xfrm_state *x, struct sk_buff *skb) |
21 | { | |
22 | return xfrm4_extract_header(skb); | |
23 | } | |
24 | ||
b05e1066 PM |
25 | static inline int xfrm4_rcv_encap_finish(struct sk_buff *skb) |
26 | { | |
adf30907 | 27 | if (skb_dst(skb) == NULL) { |
eddc9ec5 ACM |
28 | const struct iphdr *iph = ip_hdr(skb); |
29 | ||
4a94445c ED |
30 | if (ip_route_input_noref(skb, iph->daddr, iph->saddr, |
31 | iph->tos, skb->dev)) | |
b05e1066 PM |
32 | goto drop; |
33 | } | |
34 | return dst_input(skb); | |
35 | drop: | |
36 | kfree_skb(skb); | |
37 | return NET_RX_DROP; | |
38 | } | |
b05e1066 | 39 | |
c4541b41 HX |
40 | int xfrm4_rcv_encap(struct sk_buff *skb, int nexthdr, __be32 spi, |
41 | int encap_type) | |
1da177e4 | 42 | { |
2fcb45b6 | 43 | XFRM_SPI_SKB_CB(skb)->family = AF_INET; |
716062fd HX |
44 | XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr); |
45 | return xfrm_input(skb, nexthdr, spi, encap_type); | |
46 | } | |
47 | EXPORT_SYMBOL(xfrm4_rcv_encap); | |
b05e1066 | 48 | |
716062fd HX |
49 | int xfrm4_transport_finish(struct sk_buff *skb, int async) |
50 | { | |
60d5fcfb HX |
51 | struct iphdr *iph = ip_hdr(skb); |
52 | ||
53 | iph->protocol = XFRM_MODE_SKB_CB(skb)->protocol; | |
54 | ||
0883ae0e HX |
55 | #ifndef CONFIG_NETFILTER |
56 | if (!async) | |
57 | return -iph->protocol; | |
58 | #endif | |
59 | ||
716062fd | 60 | __skb_push(skb, skb->data - skb_network_header(skb)); |
60d5fcfb HX |
61 | iph->tot_len = htons(skb->len); |
62 | ip_send_check(iph); | |
b05e1066 | 63 | |
9bbc768a | 64 | NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING, skb, skb->dev, NULL, |
716062fd HX |
65 | xfrm4_rcv_encap_finish); |
66 | return 0; | |
1da177e4 | 67 | } |
067b207b JC |
68 | |
69 | /* If it's a keepalive packet, then just eat it. | |
70 | * If it's an encapsulated packet, then pass it to the | |
71 | * IPsec xfrm input. | |
72 | * Returns 0 if skb passed to xfrm or was dropped. | |
73 | * Returns >0 if skb should be passed to UDP. | |
74 | * Returns <0 if skb should be resubmitted (-ret is protocol) | |
75 | */ | |
76 | int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb) | |
77 | { | |
78 | struct udp_sock *up = udp_sk(sk); | |
79 | struct udphdr *uh; | |
80 | struct iphdr *iph; | |
81 | int iphlen, len; | |
067b207b JC |
82 | |
83 | __u8 *udpdata; | |
84 | __be32 *udpdata32; | |
85 | __u16 encap_type = up->encap_type; | |
86 | ||
87 | /* if this is not encapsulated socket, then just return now */ | |
88 | if (!encap_type) | |
89 | return 1; | |
90 | ||
91 | /* If this is a paged skb, make sure we pull up | |
92 | * whatever data we need to look at. */ | |
93 | len = skb->len - sizeof(struct udphdr); | |
94 | if (!pskb_may_pull(skb, sizeof(struct udphdr) + min(len, 8))) | |
95 | return 1; | |
96 | ||
97 | /* Now we can get the pointers */ | |
98 | uh = udp_hdr(skb); | |
99 | udpdata = (__u8 *)uh + sizeof(struct udphdr); | |
100 | udpdata32 = (__be32 *)udpdata; | |
101 | ||
102 | switch (encap_type) { | |
103 | default: | |
104 | case UDP_ENCAP_ESPINUDP: | |
105 | /* Check if this is a keepalive packet. If so, eat it. */ | |
106 | if (len == 1 && udpdata[0] == 0xff) { | |
107 | goto drop; | |
108 | } else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) { | |
109 | /* ESP Packet without Non-ESP header */ | |
110 | len = sizeof(struct udphdr); | |
111 | } else | |
112 | /* Must be an IKE packet.. pass it through */ | |
113 | return 1; | |
114 | break; | |
115 | case UDP_ENCAP_ESPINUDP_NON_IKE: | |
116 | /* Check if this is a keepalive packet. If so, eat it. */ | |
117 | if (len == 1 && udpdata[0] == 0xff) { | |
118 | goto drop; | |
119 | } else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) && | |
120 | udpdata32[0] == 0 && udpdata32[1] == 0) { | |
121 | ||
122 | /* ESP Packet with Non-IKE marker */ | |
123 | len = sizeof(struct udphdr) + 2 * sizeof(u32); | |
124 | } else | |
125 | /* Must be an IKE packet.. pass it through */ | |
126 | return 1; | |
127 | break; | |
128 | } | |
129 | ||
130 | /* At this point we are sure that this is an ESPinUDP packet, | |
131 | * so we need to remove 'len' bytes from the packet (the UDP | |
132 | * header and optional ESP marker bytes) and then modify the | |
133 | * protocol to ESP, and then call into the transform receiver. | |
134 | */ | |
135 | if (skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) | |
136 | goto drop; | |
137 | ||
138 | /* Now we can update and verify the packet length... */ | |
139 | iph = ip_hdr(skb); | |
140 | iphlen = iph->ihl << 2; | |
141 | iph->tot_len = htons(ntohs(iph->tot_len) - len); | |
142 | if (skb->len < iphlen + len) { | |
143 | /* packet is too small!?! */ | |
144 | goto drop; | |
145 | } | |
146 | ||
147 | /* pull the data buffer up to the ESP header and set the | |
148 | * transport header to point to ESP. Keep UDP on the stack | |
149 | * for later. | |
150 | */ | |
151 | __skb_pull(skb, len); | |
152 | skb_reset_transport_header(skb); | |
153 | ||
067b207b | 154 | /* process ESP */ |
f2712fd0 | 155 | return xfrm4_rcv_encap(skb, IPPROTO_ESP, 0, encap_type); |
067b207b JC |
156 | |
157 | drop: | |
158 | kfree_skb(skb); | |
159 | return 0; | |
160 | } | |
161 | ||
162 | int xfrm4_rcv(struct sk_buff *skb) | |
163 | { | |
c4541b41 | 164 | return xfrm4_rcv_spi(skb, ip_hdr(skb)->protocol, 0); |
067b207b JC |
165 | } |
166 | ||
167 | EXPORT_SYMBOL(xfrm4_rcv); |