blob: 60b032f58ccc9ffca8617de21c72288b919889b7 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +09009 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070010 */
11
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090012#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070013#include <linux/module.h>
14#include <linux/string.h>
Patrick McHardyb05e1062006-01-06 23:03:34 -080015#include <linux/netfilter.h>
16#include <linux/netfilter_ipv4.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include <net/ip.h>
18#include <net/xfrm.h>
19
Herbert Xu227620e2007-11-13 21:41:28 -080020int xfrm4_extract_input(struct xfrm_state *x, struct sk_buff *skb)
21{
22 return xfrm4_extract_header(skb);
23}
24
David Miller7026b1d2015-04-05 22:19:04 -040025static inline int xfrm4_rcv_encap_finish(struct sock *sk, struct sk_buff *skb)
Patrick McHardyb05e1062006-01-06 23:03:34 -080026{
Ian Morris51456b22015-04-03 09:17:26 +010027 if (!skb_dst(skb)) {
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -070028 const struct iphdr *iph = ip_hdr(skb);
29
David S. Millerc6cffba2012-07-26 11:14:38 +000030 if (ip_route_input_noref(skb, iph->daddr, iph->saddr,
31 iph->tos, skb->dev))
Patrick McHardyb05e1062006-01-06 23:03:34 -080032 goto drop;
33 }
34 return dst_input(skb);
35drop:
36 kfree_skb(skb);
37 return NET_RX_DROP;
38}
Patrick McHardyb05e1062006-01-06 23:03:34 -080039
Herbert Xu716062f2007-11-13 21:44:23 -080040int xfrm4_transport_finish(struct sk_buff *skb, int async)
41{
Herbert Xu60d5fcf2007-11-19 18:47:58 -080042 struct iphdr *iph = ip_hdr(skb);
43
44 iph->protocol = XFRM_MODE_SKB_CB(skb)->protocol;
45
Herbert Xu0883ae02007-12-30 21:10:14 -080046#ifndef CONFIG_NETFILTER
47 if (!async)
48 return -iph->protocol;
49#endif
50
Herbert Xu716062f2007-11-13 21:44:23 -080051 __skb_push(skb, skb->data - skb_network_header(skb));
Herbert Xu60d5fcf2007-11-19 18:47:58 -080052 iph->tot_len = htons(skb->len);
53 ip_send_check(iph);
Herbert Xu716062f2007-11-13 21:44:23 -080054
David Miller7026b1d2015-04-05 22:19:04 -040055 NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING, NULL, skb,
56 skb->dev, NULL,
Herbert Xu716062f2007-11-13 21:44:23 -080057 xfrm4_rcv_encap_finish);
58 return 0;
Herbert Xu716062f2007-11-13 21:44:23 -080059}
60
James Chapman067b2072007-07-05 17:08:05 -070061/* If it's a keepalive packet, then just eat it.
62 * If it's an encapsulated packet, then pass it to the
63 * IPsec xfrm input.
64 * Returns 0 if skb passed to xfrm or was dropped.
65 * Returns >0 if skb should be passed to UDP.
66 * Returns <0 if skb should be resubmitted (-ret is protocol)
67 */
68int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
69{
70 struct udp_sock *up = udp_sk(sk);
71 struct udphdr *uh;
72 struct iphdr *iph;
73 int iphlen, len;
James Chapman067b2072007-07-05 17:08:05 -070074
75 __u8 *udpdata;
76 __be32 *udpdata32;
77 __u16 encap_type = up->encap_type;
78
79 /* if this is not encapsulated socket, then just return now */
80 if (!encap_type)
81 return 1;
82
83 /* If this is a paged skb, make sure we pull up
84 * whatever data we need to look at. */
85 len = skb->len - sizeof(struct udphdr);
86 if (!pskb_may_pull(skb, sizeof(struct udphdr) + min(len, 8)))
87 return 1;
88
89 /* Now we can get the pointers */
90 uh = udp_hdr(skb);
91 udpdata = (__u8 *)uh + sizeof(struct udphdr);
92 udpdata32 = (__be32 *)udpdata;
93
94 switch (encap_type) {
95 default:
96 case UDP_ENCAP_ESPINUDP:
97 /* Check if this is a keepalive packet. If so, eat it. */
98 if (len == 1 && udpdata[0] == 0xff) {
99 goto drop;
100 } else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) {
101 /* ESP Packet without Non-ESP header */
102 len = sizeof(struct udphdr);
103 } else
104 /* Must be an IKE packet.. pass it through */
105 return 1;
106 break;
107 case UDP_ENCAP_ESPINUDP_NON_IKE:
108 /* Check if this is a keepalive packet. If so, eat it. */
109 if (len == 1 && udpdata[0] == 0xff) {
110 goto drop;
111 } else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) &&
112 udpdata32[0] == 0 && udpdata32[1] == 0) {
113
114 /* ESP Packet with Non-IKE marker */
115 len = sizeof(struct udphdr) + 2 * sizeof(u32);
116 } else
117 /* Must be an IKE packet.. pass it through */
118 return 1;
119 break;
120 }
121
122 /* At this point we are sure that this is an ESPinUDP packet,
123 * so we need to remove 'len' bytes from the packet (the UDP
124 * header and optional ESP marker bytes) and then modify the
125 * protocol to ESP, and then call into the transform receiver.
126 */
Pravin B Shelar14bbd6a2013-02-14 09:44:49 +0000127 if (skb_unclone(skb, GFP_ATOMIC))
James Chapman067b2072007-07-05 17:08:05 -0700128 goto drop;
129
130 /* Now we can update and verify the packet length... */
131 iph = ip_hdr(skb);
132 iphlen = iph->ihl << 2;
133 iph->tot_len = htons(ntohs(iph->tot_len) - len);
134 if (skb->len < iphlen + len) {
135 /* packet is too small!?! */
136 goto drop;
137 }
138
139 /* pull the data buffer up to the ESP header and set the
140 * transport header to point to ESP. Keep UDP on the stack
141 * for later.
142 */
143 __skb_pull(skb, len);
144 skb_reset_transport_header(skb);
145
James Chapman067b2072007-07-05 17:08:05 -0700146 /* process ESP */
Herbert Xuf2712fd2008-12-26 01:31:18 -0800147 return xfrm4_rcv_encap(skb, IPPROTO_ESP, 0, encap_type);
James Chapman067b2072007-07-05 17:08:05 -0700148
149drop:
150 kfree_skb(skb);
151 return 0;
152}
153
154int xfrm4_rcv(struct sk_buff *skb)
155{
Herbert Xuc4541b42007-10-17 21:28:53 -0700156 return xfrm4_rcv_spi(skb, ip_hdr(skb)->protocol, 0);
James Chapman067b2072007-07-05 17:08:05 -0700157}
James Chapman067b2072007-07-05 17:08:05 -0700158EXPORT_SYMBOL(xfrm4_rcv);