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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * xfrm4_input.c
4 *
5 * Changes:
6 * YOSHIFUJI Hideaki @USAGI
7 * Split up af-specific portion
8 * Derek Atkins <derek@ihtfp.com>
9 * Add Encapsulation support
10 *
11 */
12
13#include <linux/slab.h>
14#include <linux/module.h>
15#include <linux/string.h>
16#include <linux/netfilter.h>
17#include <linux/netfilter_ipv4.h>
18#include <net/ip.h>
19#include <net/xfrm.h>
20
21int xfrm4_extract_input(struct xfrm_state *x, struct sk_buff *skb)
22{
23 return xfrm4_extract_header(skb);
24}
25
26static int xfrm4_rcv_encap_finish2(struct net *net, struct sock *sk,
27 struct sk_buff *skb)
28{
29 return dst_input(skb);
30}
31
32static inline int xfrm4_rcv_encap_finish(struct net *net, struct sock *sk,
33 struct sk_buff *skb)
34{
35 if (!skb_dst(skb)) {
36 const struct iphdr *iph = ip_hdr(skb);
37
38 if (ip_route_input_noref(skb, iph->daddr, iph->saddr,
39 iph->tos, skb->dev))
40 goto drop;
41 }
42
43 if (xfrm_trans_queue(skb, xfrm4_rcv_encap_finish2))
44 goto drop;
45
46 return 0;
47drop:
48 kfree_skb(skb);
49 return NET_RX_DROP;
50}
51
52int xfrm4_transport_finish(struct sk_buff *skb, int async)
53{
54 struct xfrm_offload *xo = xfrm_offload(skb);
55 struct iphdr *iph = ip_hdr(skb);
56
57 iph->protocol = XFRM_MODE_SKB_CB(skb)->protocol;
58
59#ifndef CONFIG_NETFILTER
60 if (!async)
61 return -iph->protocol;
62#endif
63
64 __skb_push(skb, skb->data - skb_network_header(skb));
65 iph->tot_len = htons(skb->len);
66 ip_send_check(iph);
67
68 if (xo && (xo->flags & XFRM_GRO)) {
69 skb_mac_header_rebuild(skb);
70 return 0;
71 }
72
73 NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING,
74 dev_net(skb->dev), NULL, skb, skb->dev, NULL,
75 xfrm4_rcv_encap_finish);
76 return 0;
77}
78
79/* If it's a keepalive packet, then just eat it.
80 * If it's an encapsulated packet, then pass it to the
81 * IPsec xfrm input.
82 * Returns 0 if skb passed to xfrm or was dropped.
83 * Returns >0 if skb should be passed to UDP.
84 * Returns <0 if skb should be resubmitted (-ret is protocol)
85 */
86int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
87{
88 struct udp_sock *up = udp_sk(sk);
89 struct udphdr *uh;
90 struct iphdr *iph;
91 int iphlen, len;
92
93 __u8 *udpdata;
94 __be32 *udpdata32;
95 __u16 encap_type = up->encap_type;
96
97 /* if this is not encapsulated socket, then just return now */
98 if (!encap_type)
99 return 1;
100
101 /* If this is a paged skb, make sure we pull up
102 * whatever data we need to look at. */
103 len = skb->len - sizeof(struct udphdr);
104 if (!pskb_may_pull(skb, sizeof(struct udphdr) + min(len, 8)))
105 return 1;
106
107 /* Now we can get the pointers */
108 uh = udp_hdr(skb);
109 udpdata = (__u8 *)uh + sizeof(struct udphdr);
110 udpdata32 = (__be32 *)udpdata;
111
112 switch (encap_type) {
113 default:
114 case UDP_ENCAP_ESPINUDP:
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 > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) {
119 /* ESP Packet without Non-ESP header */
120 len = sizeof(struct udphdr);
121 } else
122 /* Must be an IKE packet.. pass it through */
123 return 1;
124 break;
125 case UDP_ENCAP_ESPINUDP_NON_IKE:
126 /* Check if this is a keepalive packet. If so, eat it. */
127 if (len == 1 && udpdata[0] == 0xff) {
128 goto drop;
129 } else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) &&
130 udpdata32[0] == 0 && udpdata32[1] == 0) {
131
132 /* ESP Packet with Non-IKE marker */
133 len = sizeof(struct udphdr) + 2 * sizeof(u32);
134 } else
135 /* Must be an IKE packet.. pass it through */
136 return 1;
137 break;
138 }
139
140 /* At this point we are sure that this is an ESPinUDP packet,
141 * so we need to remove 'len' bytes from the packet (the UDP
142 * header and optional ESP marker bytes) and then modify the
143 * protocol to ESP, and then call into the transform receiver.
144 */
145 if (skb_unclone(skb, GFP_ATOMIC))
146 goto drop;
147
148 /* Now we can update and verify the packet length... */
149 iph = ip_hdr(skb);
150 iphlen = iph->ihl << 2;
151 iph->tot_len = htons(ntohs(iph->tot_len) - len);
152 if (skb->len < iphlen + len) {
153 /* packet is too small!?! */
154 goto drop;
155 }
156
157 /* pull the data buffer up to the ESP header and set the
158 * transport header to point to ESP. Keep UDP on the stack
159 * for later.
160 */
161 __skb_pull(skb, len);
162 skb_reset_transport_header(skb);
163
164 /* process ESP */
165 return xfrm4_rcv_encap(skb, IPPROTO_ESP, 0, encap_type);
166
167drop:
168 kfree_skb(skb);
169 return 0;
170}
171
172int xfrm4_rcv(struct sk_buff *skb)
173{
174 return xfrm4_rcv_spi(skb, ip_hdr(skb)->protocol, 0);
175}
176EXPORT_SYMBOL(xfrm4_rcv);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * xfrm4_input.c
4 *
5 * Changes:
6 * YOSHIFUJI Hideaki @USAGI
7 * Split up af-specific portion
8 * Derek Atkins <derek@ihtfp.com>
9 * Add Encapsulation support
10 *
11 */
12
13#include <linux/slab.h>
14#include <linux/module.h>
15#include <linux/string.h>
16#include <linux/netfilter.h>
17#include <linux/netfilter_ipv4.h>
18#include <net/ip.h>
19#include <net/xfrm.h>
20#include <net/protocol.h>
21#include <net/gro.h>
22
23static int xfrm4_rcv_encap_finish2(struct net *net, struct sock *sk,
24 struct sk_buff *skb)
25{
26 return dst_input(skb);
27}
28
29static inline int xfrm4_rcv_encap_finish(struct net *net, struct sock *sk,
30 struct sk_buff *skb)
31{
32 if (!skb_dst(skb)) {
33 const struct iphdr *iph = ip_hdr(skb);
34
35 if (ip_route_input_noref(skb, iph->daddr, iph->saddr,
36 iph->tos, skb->dev))
37 goto drop;
38 }
39
40 if (xfrm_trans_queue(skb, xfrm4_rcv_encap_finish2))
41 goto drop;
42
43 return 0;
44drop:
45 kfree_skb(skb);
46 return NET_RX_DROP;
47}
48
49int xfrm4_transport_finish(struct sk_buff *skb, int async)
50{
51 struct xfrm_offload *xo = xfrm_offload(skb);
52 struct iphdr *iph = ip_hdr(skb);
53
54 iph->protocol = XFRM_MODE_SKB_CB(skb)->protocol;
55
56#ifndef CONFIG_NETFILTER
57 if (!async)
58 return -iph->protocol;
59#endif
60
61 __skb_push(skb, -skb_network_offset(skb));
62 iph->tot_len = htons(skb->len);
63 ip_send_check(iph);
64
65 if (xo && (xo->flags & XFRM_GRO)) {
66 /* The full l2 header needs to be preserved so that re-injecting the packet at l2
67 * works correctly in the presence of vlan tags.
68 */
69 skb_mac_header_rebuild_full(skb, xo->orig_mac_len);
70 skb_reset_network_header(skb);
71 skb_reset_transport_header(skb);
72 return 0;
73 }
74
75 NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING,
76 dev_net(skb->dev), NULL, skb, skb->dev, NULL,
77 xfrm4_rcv_encap_finish);
78 return 0;
79}
80
81static int __xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb, bool pull)
82{
83 struct udp_sock *up = udp_sk(sk);
84 struct udphdr *uh;
85 struct iphdr *iph;
86 int iphlen, len;
87 __u8 *udpdata;
88 __be32 *udpdata32;
89 u16 encap_type;
90
91 encap_type = READ_ONCE(up->encap_type);
92 /* if this is not encapsulated socket, then just return now */
93 if (!encap_type)
94 return 1;
95
96 /* If this is a paged skb, make sure we pull up
97 * whatever data we need to look at. */
98 len = skb->len - sizeof(struct udphdr);
99 if (!pskb_may_pull(skb, sizeof(struct udphdr) + min(len, 8)))
100 return 1;
101
102 /* Now we can get the pointers */
103 uh = udp_hdr(skb);
104 udpdata = (__u8 *)uh + sizeof(struct udphdr);
105 udpdata32 = (__be32 *)udpdata;
106
107 switch (encap_type) {
108 default:
109 case UDP_ENCAP_ESPINUDP:
110 /* Check if this is a keepalive packet. If so, eat it. */
111 if (len == 1 && udpdata[0] == 0xff) {
112 return -EINVAL;
113 } else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) {
114 /* ESP Packet without Non-ESP header */
115 len = sizeof(struct udphdr);
116 } else
117 /* Must be an IKE packet.. pass it through */
118 return 1;
119 break;
120 case UDP_ENCAP_ESPINUDP_NON_IKE:
121 /* Check if this is a keepalive packet. If so, eat it. */
122 if (len == 1 && udpdata[0] == 0xff) {
123 return -EINVAL;
124 } else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) &&
125 udpdata32[0] == 0 && udpdata32[1] == 0) {
126
127 /* ESP Packet with Non-IKE marker */
128 len = sizeof(struct udphdr) + 2 * sizeof(u32);
129 } else
130 /* Must be an IKE packet.. pass it through */
131 return 1;
132 break;
133 }
134
135 /* At this point we are sure that this is an ESPinUDP packet,
136 * so we need to remove 'len' bytes from the packet (the UDP
137 * header and optional ESP marker bytes) and then modify the
138 * protocol to ESP, and then call into the transform receiver.
139 */
140 if (skb_unclone(skb, GFP_ATOMIC))
141 return -EINVAL;
142
143 /* Now we can update and verify the packet length... */
144 iph = ip_hdr(skb);
145 iphlen = iph->ihl << 2;
146 iph->tot_len = htons(ntohs(iph->tot_len) - len);
147 if (skb->len < iphlen + len) {
148 /* packet is too small!?! */
149 return -EINVAL;
150 }
151
152 /* pull the data buffer up to the ESP header and set the
153 * transport header to point to ESP. Keep UDP on the stack
154 * for later.
155 */
156 if (pull) {
157 __skb_pull(skb, len);
158 skb_reset_transport_header(skb);
159 } else {
160 skb_set_transport_header(skb, len);
161 }
162
163 /* process ESP */
164 return 0;
165}
166
167/* If it's a keepalive packet, then just eat it.
168 * If it's an encapsulated packet, then pass it to the
169 * IPsec xfrm input.
170 * Returns 0 if skb passed to xfrm or was dropped.
171 * Returns >0 if skb should be passed to UDP.
172 * Returns <0 if skb should be resubmitted (-ret is protocol)
173 */
174int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
175{
176 int ret;
177
178 ret = __xfrm4_udp_encap_rcv(sk, skb, true);
179 if (!ret)
180 return xfrm4_rcv_encap(skb, IPPROTO_ESP, 0,
181 udp_sk(sk)->encap_type);
182
183 if (ret < 0) {
184 kfree_skb(skb);
185 return 0;
186 }
187
188 return ret;
189}
190EXPORT_SYMBOL(xfrm4_udp_encap_rcv);
191
192struct sk_buff *xfrm4_gro_udp_encap_rcv(struct sock *sk, struct list_head *head,
193 struct sk_buff *skb)
194{
195 int offset = skb_gro_offset(skb);
196 const struct net_offload *ops;
197 struct sk_buff *pp = NULL;
198 int ret;
199
200 offset = offset - sizeof(struct udphdr);
201
202 if (!pskb_pull(skb, offset))
203 return NULL;
204
205 rcu_read_lock();
206 ops = rcu_dereference(inet_offloads[IPPROTO_ESP]);
207 if (!ops || !ops->callbacks.gro_receive)
208 goto out;
209
210 ret = __xfrm4_udp_encap_rcv(sk, skb, false);
211 if (ret)
212 goto out;
213
214 skb_push(skb, offset);
215 NAPI_GRO_CB(skb)->proto = IPPROTO_UDP;
216
217 pp = call_gro_receive(ops->callbacks.gro_receive, head, skb);
218 rcu_read_unlock();
219
220 return pp;
221
222out:
223 rcu_read_unlock();
224 skb_push(skb, offset);
225 NAPI_GRO_CB(skb)->same_flow = 0;
226 NAPI_GRO_CB(skb)->flush = 1;
227
228 return NULL;
229}
230EXPORT_SYMBOL(xfrm4_gro_udp_encap_rcv);
231
232int xfrm4_rcv(struct sk_buff *skb)
233{
234 return xfrm4_rcv_spi(skb, ip_hdr(skb)->protocol, 0);
235}
236EXPORT_SYMBOL(xfrm4_rcv);