blob: 1fc684111ce6afe6798bb21f5dcbcbcab53b9f6b [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
Eric W. Biederman0c4b51f2015-09-15 20:04:18 -050025static inline int xfrm4_rcv_encap_finish(struct net *net, struct sock *sk,
26 struct sk_buff *skb)
Patrick McHardyb05e1062006-01-06 23:03:34 -080027{
Ian Morris51456b22015-04-03 09:17:26 +010028 if (!skb_dst(skb)) {
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -070029 const struct iphdr *iph = ip_hdr(skb);
30
David S. Millerc6cffba2012-07-26 11:14:38 +000031 if (ip_route_input_noref(skb, iph->daddr, iph->saddr,
32 iph->tos, skb->dev))
Patrick McHardyb05e1062006-01-06 23:03:34 -080033 goto drop;
34 }
35 return dst_input(skb);
36drop:
37 kfree_skb(skb);
38 return NET_RX_DROP;
39}
Patrick McHardyb05e1062006-01-06 23:03:34 -080040
Herbert Xu716062f2007-11-13 21:44:23 -080041int xfrm4_transport_finish(struct sk_buff *skb, int async)
42{
Steffen Klassert7785bba2017-02-15 09:40:00 +010043 struct xfrm_offload *xo = xfrm_offload(skb);
Herbert Xu60d5fcf2007-11-19 18:47:58 -080044 struct iphdr *iph = ip_hdr(skb);
45
46 iph->protocol = XFRM_MODE_SKB_CB(skb)->protocol;
47
Herbert Xu0883ae02007-12-30 21:10:14 -080048#ifndef CONFIG_NETFILTER
49 if (!async)
50 return -iph->protocol;
51#endif
52
Herbert Xu716062f2007-11-13 21:44:23 -080053 __skb_push(skb, skb->data - skb_network_header(skb));
Herbert Xu60d5fcf2007-11-19 18:47:58 -080054 iph->tot_len = htons(skb->len);
55 ip_send_check(iph);
Herbert Xu716062f2007-11-13 21:44:23 -080056
Steffen Klassert7785bba2017-02-15 09:40:00 +010057 if (xo && (xo->flags & XFRM_GRO)) {
58 skb_mac_header_rebuild(skb);
59 return 0;
60 }
61
Eric W. Biederman29a26a52015-09-15 20:04:16 -050062 NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING,
63 dev_net(skb->dev), NULL, skb, skb->dev, NULL,
Herbert Xu716062f2007-11-13 21:44:23 -080064 xfrm4_rcv_encap_finish);
65 return 0;
Herbert Xu716062f2007-11-13 21:44:23 -080066}
67
James Chapman067b2072007-07-05 17:08:05 -070068/* 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 */
75int 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;
James Chapman067b2072007-07-05 17:08:05 -070081
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 */
Pravin B Shelar14bbd6a2013-02-14 09:44:49 +0000134 if (skb_unclone(skb, GFP_ATOMIC))
James Chapman067b2072007-07-05 17:08:05 -0700135 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
James Chapman067b2072007-07-05 17:08:05 -0700153 /* process ESP */
Herbert Xuf2712fd2008-12-26 01:31:18 -0800154 return xfrm4_rcv_encap(skb, IPPROTO_ESP, 0, encap_type);
James Chapman067b2072007-07-05 17:08:05 -0700155
156drop:
157 kfree_skb(skb);
158 return 0;
159}
160
161int xfrm4_rcv(struct sk_buff *skb)
162{
Herbert Xuc4541b42007-10-17 21:28:53 -0700163 return xfrm4_rcv_spi(skb, ip_hdr(skb)->protocol, 0);
James Chapman067b2072007-07-05 17:08:05 -0700164}
James Chapman067b2072007-07-05 17:08:05 -0700165EXPORT_SYMBOL(xfrm4_rcv);