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 | ||
227620e2 HX |
19 | int xfrm4_extract_input(struct xfrm_state *x, struct sk_buff *skb) |
20 | { | |
21 | return xfrm4_extract_header(skb); | |
22 | } | |
23 | ||
b05e1066 PM |
24 | #ifdef CONFIG_NETFILTER |
25 | static inline int xfrm4_rcv_encap_finish(struct sk_buff *skb) | |
26 | { | |
b05e1066 | 27 | if (skb->dst == NULL) { |
eddc9ec5 ACM |
28 | const struct iphdr *iph = ip_hdr(skb); |
29 | ||
b05e1066 | 30 | if (ip_route_input(skb, iph->daddr, iph->saddr, iph->tos, |
e905a9ed | 31 | 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 | } | |
39 | #endif | |
40 | ||
c4541b41 HX |
41 | int xfrm4_rcv_encap(struct sk_buff *skb, int nexthdr, __be32 spi, |
42 | int encap_type) | |
1da177e4 | 43 | { |
716062fd HX |
44 | XFRM_SPI_SKB_CB(skb)->nhoff = offsetof(struct iphdr, protocol); |
45 | XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr); | |
46 | return xfrm_input(skb, nexthdr, spi, encap_type); | |
47 | } | |
48 | EXPORT_SYMBOL(xfrm4_rcv_encap); | |
b05e1066 | 49 | |
716062fd HX |
50 | int xfrm4_transport_finish(struct sk_buff *skb, int async) |
51 | { | |
b05e1066 | 52 | #ifdef CONFIG_NETFILTER |
716062fd HX |
53 | __skb_push(skb, skb->data - skb_network_header(skb)); |
54 | ip_hdr(skb)->tot_len = htons(skb->len); | |
55 | ip_send_check(ip_hdr(skb)); | |
b05e1066 | 56 | |
716062fd HX |
57 | NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, skb->dev, NULL, |
58 | xfrm4_rcv_encap_finish); | |
59 | return 0; | |
b05e1066 | 60 | #else |
716062fd | 61 | return -ip_hdr(skb)->protocol; |
b05e1066 | 62 | #endif |
1da177e4 | 63 | } |
067b207b JC |
64 | |
65 | /* If it's a keepalive packet, then just eat it. | |
66 | * If it's an encapsulated packet, then pass it to the | |
67 | * IPsec xfrm input. | |
68 | * Returns 0 if skb passed to xfrm or was dropped. | |
69 | * Returns >0 if skb should be passed to UDP. | |
70 | * Returns <0 if skb should be resubmitted (-ret is protocol) | |
71 | */ | |
72 | int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb) | |
73 | { | |
74 | struct udp_sock *up = udp_sk(sk); | |
75 | struct udphdr *uh; | |
76 | struct iphdr *iph; | |
77 | int iphlen, len; | |
78 | int ret; | |
79 | ||
80 | __u8 *udpdata; | |
81 | __be32 *udpdata32; | |
82 | __u16 encap_type = up->encap_type; | |
83 | ||
84 | /* if this is not encapsulated socket, then just return now */ | |
85 | if (!encap_type) | |
86 | return 1; | |
87 | ||
88 | /* If this is a paged skb, make sure we pull up | |
89 | * whatever data we need to look at. */ | |
90 | len = skb->len - sizeof(struct udphdr); | |
91 | if (!pskb_may_pull(skb, sizeof(struct udphdr) + min(len, 8))) | |
92 | return 1; | |
93 | ||
94 | /* Now we can get the pointers */ | |
95 | uh = udp_hdr(skb); | |
96 | udpdata = (__u8 *)uh + sizeof(struct udphdr); | |
97 | udpdata32 = (__be32 *)udpdata; | |
98 | ||
99 | switch (encap_type) { | |
100 | default: | |
101 | case UDP_ENCAP_ESPINUDP: | |
102 | /* Check if this is a keepalive packet. If so, eat it. */ | |
103 | if (len == 1 && udpdata[0] == 0xff) { | |
104 | goto drop; | |
105 | } else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) { | |
106 | /* ESP Packet without Non-ESP header */ | |
107 | len = sizeof(struct udphdr); | |
108 | } else | |
109 | /* Must be an IKE packet.. pass it through */ | |
110 | return 1; | |
111 | break; | |
112 | case UDP_ENCAP_ESPINUDP_NON_IKE: | |
113 | /* Check if this is a keepalive packet. If so, eat it. */ | |
114 | if (len == 1 && udpdata[0] == 0xff) { | |
115 | goto drop; | |
116 | } else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) && | |
117 | udpdata32[0] == 0 && udpdata32[1] == 0) { | |
118 | ||
119 | /* ESP Packet with Non-IKE marker */ | |
120 | len = sizeof(struct udphdr) + 2 * sizeof(u32); | |
121 | } else | |
122 | /* Must be an IKE packet.. pass it through */ | |
123 | return 1; | |
124 | break; | |
125 | } | |
126 | ||
127 | /* At this point we are sure that this is an ESPinUDP packet, | |
128 | * so we need to remove 'len' bytes from the packet (the UDP | |
129 | * header and optional ESP marker bytes) and then modify the | |
130 | * protocol to ESP, and then call into the transform receiver. | |
131 | */ | |
132 | if (skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) | |
133 | goto drop; | |
134 | ||
135 | /* Now we can update and verify the packet length... */ | |
136 | iph = ip_hdr(skb); | |
137 | iphlen = iph->ihl << 2; | |
138 | iph->tot_len = htons(ntohs(iph->tot_len) - len); | |
139 | if (skb->len < iphlen + len) { | |
140 | /* packet is too small!?! */ | |
141 | goto drop; | |
142 | } | |
143 | ||
144 | /* pull the data buffer up to the ESP header and set the | |
145 | * transport header to point to ESP. Keep UDP on the stack | |
146 | * for later. | |
147 | */ | |
148 | __skb_pull(skb, len); | |
149 | skb_reset_transport_header(skb); | |
150 | ||
067b207b | 151 | /* process ESP */ |
c4541b41 | 152 | ret = xfrm4_rcv_encap(skb, IPPROTO_ESP, 0, encap_type); |
067b207b JC |
153 | return ret; |
154 | ||
155 | drop: | |
156 | kfree_skb(skb); | |
157 | return 0; | |
158 | } | |
159 | ||
160 | int xfrm4_rcv(struct sk_buff *skb) | |
161 | { | |
c4541b41 | 162 | return xfrm4_rcv_spi(skb, ip_hdr(skb)->protocol, 0); |
067b207b JC |
163 | } |
164 | ||
165 | EXPORT_SYMBOL(xfrm4_rcv); |