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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 | ||
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 | ||
0c4b51f0 EB |
25 | static inline int xfrm4_rcv_encap_finish(struct net *net, struct sock *sk, |
26 | struct sk_buff *skb) | |
b05e1066 | 27 | { |
51456b29 | 28 | if (!skb_dst(skb)) { |
eddc9ec5 ACM |
29 | const struct iphdr *iph = ip_hdr(skb); |
30 | ||
c6cffba4 DM |
31 | if (ip_route_input_noref(skb, iph->daddr, iph->saddr, |
32 | iph->tos, skb->dev)) | |
b05e1066 PM |
33 | goto drop; |
34 | } | |
35 | return dst_input(skb); | |
36 | drop: | |
37 | kfree_skb(skb); | |
38 | return NET_RX_DROP; | |
39 | } | |
b05e1066 | 40 | |
716062fd HX |
41 | int xfrm4_transport_finish(struct sk_buff *skb, int async) |
42 | { | |
7785bba2 | 43 | struct xfrm_offload *xo = xfrm_offload(skb); |
60d5fcfb HX |
44 | struct iphdr *iph = ip_hdr(skb); |
45 | ||
46 | iph->protocol = XFRM_MODE_SKB_CB(skb)->protocol; | |
47 | ||
0883ae0e HX |
48 | #ifndef CONFIG_NETFILTER |
49 | if (!async) | |
50 | return -iph->protocol; | |
51 | #endif | |
52 | ||
716062fd | 53 | __skb_push(skb, skb->data - skb_network_header(skb)); |
60d5fcfb HX |
54 | iph->tot_len = htons(skb->len); |
55 | ip_send_check(iph); | |
b05e1066 | 56 | |
7785bba2 SK |
57 | if (xo && (xo->flags & XFRM_GRO)) { |
58 | skb_mac_header_rebuild(skb); | |
59 | return 0; | |
60 | } | |
61 | ||
29a26a56 EB |
62 | NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING, |
63 | dev_net(skb->dev), NULL, skb, skb->dev, NULL, | |
716062fd HX |
64 | xfrm4_rcv_encap_finish); |
65 | return 0; | |
1da177e4 | 66 | } |
067b207b JC |
67 | |
68 | /* If it's a keepalive packet, then just eat it. | |
69 | * If it's an encapsulated packet, then pass it to the | |
70 | * IPsec xfrm input. | |
71 | * Returns 0 if skb passed to xfrm or was dropped. | |
72 | * Returns >0 if skb should be passed to UDP. | |
73 | * Returns <0 if skb should be resubmitted (-ret is protocol) | |
74 | */ | |
75 | int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb) | |
76 | { | |
77 | struct udp_sock *up = udp_sk(sk); | |
78 | struct udphdr *uh; | |
79 | struct iphdr *iph; | |
80 | int iphlen, len; | |
067b207b JC |
81 | |
82 | __u8 *udpdata; | |
83 | __be32 *udpdata32; | |
84 | __u16 encap_type = up->encap_type; | |
85 | ||
86 | /* if this is not encapsulated socket, then just return now */ | |
87 | if (!encap_type) | |
88 | return 1; | |
89 | ||
90 | /* If this is a paged skb, make sure we pull up | |
91 | * whatever data we need to look at. */ | |
92 | len = skb->len - sizeof(struct udphdr); | |
93 | if (!pskb_may_pull(skb, sizeof(struct udphdr) + min(len, 8))) | |
94 | return 1; | |
95 | ||
96 | /* Now we can get the pointers */ | |
97 | uh = udp_hdr(skb); | |
98 | udpdata = (__u8 *)uh + sizeof(struct udphdr); | |
99 | udpdata32 = (__be32 *)udpdata; | |
100 | ||
101 | switch (encap_type) { | |
102 | default: | |
103 | case UDP_ENCAP_ESPINUDP: | |
104 | /* Check if this is a keepalive packet. If so, eat it. */ | |
105 | if (len == 1 && udpdata[0] == 0xff) { | |
106 | goto drop; | |
107 | } else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) { | |
108 | /* ESP Packet without Non-ESP header */ | |
109 | len = sizeof(struct udphdr); | |
110 | } else | |
111 | /* Must be an IKE packet.. pass it through */ | |
112 | return 1; | |
113 | break; | |
114 | case UDP_ENCAP_ESPINUDP_NON_IKE: | |
115 | /* Check if this is a keepalive packet. If so, eat it. */ | |
116 | if (len == 1 && udpdata[0] == 0xff) { | |
117 | goto drop; | |
118 | } else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) && | |
119 | udpdata32[0] == 0 && udpdata32[1] == 0) { | |
120 | ||
121 | /* ESP Packet with Non-IKE marker */ | |
122 | len = sizeof(struct udphdr) + 2 * sizeof(u32); | |
123 | } else | |
124 | /* Must be an IKE packet.. pass it through */ | |
125 | return 1; | |
126 | break; | |
127 | } | |
128 | ||
129 | /* At this point we are sure that this is an ESPinUDP packet, | |
130 | * so we need to remove 'len' bytes from the packet (the UDP | |
131 | * header and optional ESP marker bytes) and then modify the | |
132 | * protocol to ESP, and then call into the transform receiver. | |
133 | */ | |
14bbd6a5 | 134 | if (skb_unclone(skb, GFP_ATOMIC)) |
067b207b JC |
135 | goto drop; |
136 | ||
137 | /* Now we can update and verify the packet length... */ | |
138 | iph = ip_hdr(skb); | |
139 | iphlen = iph->ihl << 2; | |
140 | iph->tot_len = htons(ntohs(iph->tot_len) - len); | |
141 | if (skb->len < iphlen + len) { | |
142 | /* packet is too small!?! */ | |
143 | goto drop; | |
144 | } | |
145 | ||
146 | /* pull the data buffer up to the ESP header and set the | |
147 | * transport header to point to ESP. Keep UDP on the stack | |
148 | * for later. | |
149 | */ | |
150 | __skb_pull(skb, len); | |
151 | skb_reset_transport_header(skb); | |
152 | ||
067b207b | 153 | /* process ESP */ |
f2712fd0 | 154 | return xfrm4_rcv_encap(skb, IPPROTO_ESP, 0, encap_type); |
067b207b JC |
155 | |
156 | drop: | |
157 | kfree_skb(skb); | |
158 | return 0; | |
159 | } | |
160 | ||
161 | int xfrm4_rcv(struct sk_buff *skb) | |
162 | { | |
c4541b41 | 163 | return xfrm4_rcv_spi(skb, ip_hdr(skb)->protocol, 0); |
067b207b | 164 | } |
067b207b | 165 | EXPORT_SYMBOL(xfrm4_rcv); |