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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#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 ip4h_dscp(iph), 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 }
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 */
127 if (skb_unclone(skb, GFP_ATOMIC))
128 return -EINVAL;
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 return -EINVAL;
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 if (pull) {
144 __skb_pull(skb, len);
145 skb_reset_transport_header(skb);
146 } else {
147 skb_set_transport_header(skb, len);
148 }
149
150 /* process ESP */
151 return 0;
152}
153
154/* If it's a keepalive packet, then just eat it.
155 * If it's an encapsulated packet, then pass it to the
156 * IPsec xfrm input.
157 * Returns 0 if skb passed to xfrm or was dropped.
158 * Returns >0 if skb should be passed to UDP.
159 * Returns <0 if skb should be resubmitted (-ret is protocol)
160 */
161int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
162{
163 int ret;
164
165 ret = __xfrm4_udp_encap_rcv(sk, skb, true);
166 if (!ret)
167 return xfrm4_rcv_encap(skb, IPPROTO_ESP, 0,
168 udp_sk(sk)->encap_type);
169
170 if (ret < 0) {
171 kfree_skb(skb);
172 return 0;
173 }
174
175 return ret;
176}
177EXPORT_SYMBOL(xfrm4_udp_encap_rcv);
178
179struct sk_buff *xfrm4_gro_udp_encap_rcv(struct sock *sk, struct list_head *head,
180 struct sk_buff *skb)
181{
182 int offset = skb_gro_offset(skb);
183 const struct net_offload *ops;
184 struct sk_buff *pp = NULL;
185 int ret;
186
187 offset = offset - sizeof(struct udphdr);
188
189 if (!pskb_pull(skb, offset))
190 return NULL;
191
192 rcu_read_lock();
193 ops = rcu_dereference(inet_offloads[IPPROTO_ESP]);
194 if (!ops || !ops->callbacks.gro_receive)
195 goto out;
196
197 ret = __xfrm4_udp_encap_rcv(sk, skb, false);
198 if (ret)
199 goto out;
200
201 skb_push(skb, offset);
202 NAPI_GRO_CB(skb)->proto = IPPROTO_UDP;
203
204 pp = call_gro_receive(ops->callbacks.gro_receive, head, skb);
205 rcu_read_unlock();
206
207 return pp;
208
209out:
210 rcu_read_unlock();
211 skb_push(skb, offset);
212 NAPI_GRO_CB(skb)->same_flow = 0;
213 NAPI_GRO_CB(skb)->flush = 1;
214
215 return NULL;
216}
217EXPORT_SYMBOL(xfrm4_gro_udp_encap_rcv);
218
219int xfrm4_rcv(struct sk_buff *skb)
220{
221 return xfrm4_rcv_spi(skb, ip_hdr(skb)->protocol, 0);
222}
223EXPORT_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->data - skb_network_header(skb));
62 iph->tot_len = htons(skb->len);
63 ip_send_check(iph);
64
65 if (xo && (xo->flags & XFRM_GRO)) {
66 skb_mac_header_rebuild(skb);
67 skb_reset_transport_header(skb);
68 return 0;
69 }
70
71 NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING,
72 dev_net(skb->dev), NULL, skb, skb->dev, NULL,
73 xfrm4_rcv_encap_finish);
74 return 0;
75}
76
77static int __xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb, bool pull)
78{
79 struct udp_sock *up = udp_sk(sk);
80 struct udphdr *uh;
81 struct iphdr *iph;
82 int iphlen, len;
83 __u8 *udpdata;
84 __be32 *udpdata32;
85 u16 encap_type;
86
87 encap_type = READ_ONCE(up->encap_type);
88 /* if this is not encapsulated socket, then just return now */
89 if (!encap_type)
90 return 1;
91
92 /* If this is a paged skb, make sure we pull up
93 * whatever data we need to look at. */
94 len = skb->len - sizeof(struct udphdr);
95 if (!pskb_may_pull(skb, sizeof(struct udphdr) + min(len, 8)))
96 return 1;
97
98 /* Now we can get the pointers */
99 uh = udp_hdr(skb);
100 udpdata = (__u8 *)uh + sizeof(struct udphdr);
101 udpdata32 = (__be32 *)udpdata;
102
103 switch (encap_type) {
104 default:
105 case UDP_ENCAP_ESPINUDP:
106 /* Check if this is a keepalive packet. If so, eat it. */
107 if (len == 1 && udpdata[0] == 0xff) {
108 return -EINVAL;
109 } else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) {
110 /* ESP Packet without Non-ESP header */
111 len = sizeof(struct udphdr);
112 } else
113 /* Must be an IKE packet.. pass it through */
114 return 1;
115 break;
116 case UDP_ENCAP_ESPINUDP_NON_IKE:
117 /* Check if this is a keepalive packet. If so, eat it. */
118 if (len == 1 && udpdata[0] == 0xff) {
119 return -EINVAL;
120 } else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) &&
121 udpdata32[0] == 0 && udpdata32[1] == 0) {
122
123 /* ESP Packet with Non-IKE marker */
124 len = sizeof(struct udphdr) + 2 * sizeof(u32);
125 } else
126 /* Must be an IKE packet.. pass it through */
127 return 1;
128 break;
129 }
130
131 /* At this point we are sure that this is an ESPinUDP packet,
132 * so we need to remove 'len' bytes from the packet (the UDP
133 * header and optional ESP marker bytes) and then modify the
134 * protocol to ESP, and then call into the transform receiver.
135 */
136 if (skb_unclone(skb, GFP_ATOMIC))
137 return -EINVAL;
138
139 /* Now we can update and verify the packet length... */
140 iph = ip_hdr(skb);
141 iphlen = iph->ihl << 2;
142 iph->tot_len = htons(ntohs(iph->tot_len) - len);
143 if (skb->len < iphlen + len) {
144 /* packet is too small!?! */
145 return -EINVAL;
146 }
147
148 /* pull the data buffer up to the ESP header and set the
149 * transport header to point to ESP. Keep UDP on the stack
150 * for later.
151 */
152 if (pull) {
153 __skb_pull(skb, len);
154 skb_reset_transport_header(skb);
155 } else {
156 skb_set_transport_header(skb, len);
157 }
158
159 /* process ESP */
160 return 0;
161}
162
163/* If it's a keepalive packet, then just eat it.
164 * If it's an encapsulated packet, then pass it to the
165 * IPsec xfrm input.
166 * Returns 0 if skb passed to xfrm or was dropped.
167 * Returns >0 if skb should be passed to UDP.
168 * Returns <0 if skb should be resubmitted (-ret is protocol)
169 */
170int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
171{
172 int ret;
173
174 ret = __xfrm4_udp_encap_rcv(sk, skb, true);
175 if (!ret)
176 return xfrm4_rcv_encap(skb, IPPROTO_ESP, 0,
177 udp_sk(sk)->encap_type);
178
179 if (ret < 0) {
180 kfree_skb(skb);
181 return 0;
182 }
183
184 return ret;
185}
186EXPORT_SYMBOL(xfrm4_udp_encap_rcv);
187
188struct sk_buff *xfrm4_gro_udp_encap_rcv(struct sock *sk, struct list_head *head,
189 struct sk_buff *skb)
190{
191 int offset = skb_gro_offset(skb);
192 const struct net_offload *ops;
193 struct sk_buff *pp = NULL;
194 int ret;
195
196 offset = offset - sizeof(struct udphdr);
197
198 if (!pskb_pull(skb, offset))
199 return NULL;
200
201 rcu_read_lock();
202 ops = rcu_dereference(inet_offloads[IPPROTO_ESP]);
203 if (!ops || !ops->callbacks.gro_receive)
204 goto out;
205
206 ret = __xfrm4_udp_encap_rcv(sk, skb, false);
207 if (ret)
208 goto out;
209
210 skb_push(skb, offset);
211 NAPI_GRO_CB(skb)->proto = IPPROTO_UDP;
212
213 pp = call_gro_receive(ops->callbacks.gro_receive, head, skb);
214 rcu_read_unlock();
215
216 return pp;
217
218out:
219 rcu_read_unlock();
220 skb_push(skb, offset);
221 NAPI_GRO_CB(skb)->same_flow = 0;
222 NAPI_GRO_CB(skb)->flush = 1;
223
224 return NULL;
225}
226EXPORT_SYMBOL(xfrm4_gro_udp_encap_rcv);
227
228int xfrm4_rcv(struct sk_buff *skb)
229{
230 return xfrm4_rcv_spi(skb, ip_hdr(skb)->protocol, 0);
231}
232EXPORT_SYMBOL(xfrm4_rcv);