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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
21static int xfrm4_rcv_encap_finish2(struct net *net, struct sock *sk,
22 struct sk_buff *skb)
23{
24 return dst_input(skb);
25}
26
27static inline int xfrm4_rcv_encap_finish(struct net *net, struct sock *sk,
28 struct sk_buff *skb)
29{
30 if (!skb_dst(skb)) {
31 const struct iphdr *iph = ip_hdr(skb);
32
33 if (ip_route_input_noref(skb, iph->daddr, iph->saddr,
34 iph->tos, skb->dev))
35 goto drop;
36 }
37
38 if (xfrm_trans_queue(skb, xfrm4_rcv_encap_finish2))
39 goto drop;
40
41 return 0;
42drop:
43 kfree_skb(skb);
44 return NET_RX_DROP;
45}
46
47int xfrm4_transport_finish(struct sk_buff *skb, int async)
48{
49 struct xfrm_offload *xo = xfrm_offload(skb);
50 struct iphdr *iph = ip_hdr(skb);
51
52 iph->protocol = XFRM_MODE_SKB_CB(skb)->protocol;
53
54#ifndef CONFIG_NETFILTER
55 if (!async)
56 return -iph->protocol;
57#endif
58
59 __skb_push(skb, skb->data - skb_network_header(skb));
60 iph->tot_len = htons(skb->len);
61 ip_send_check(iph);
62
63 if (xo && (xo->flags & XFRM_GRO)) {
64 skb_mac_header_rebuild(skb);
65 skb_reset_transport_header(skb);
66 return 0;
67 }
68
69 NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING,
70 dev_net(skb->dev), NULL, skb, skb->dev, NULL,
71 xfrm4_rcv_encap_finish);
72 return 0;
73}
74
75/* If it's a keepalive packet, then just eat it.
76 * If it's an encapsulated packet, then pass it to the
77 * IPsec xfrm input.
78 * Returns 0 if skb passed to xfrm or was dropped.
79 * Returns >0 if skb should be passed to UDP.
80 * Returns <0 if skb should be resubmitted (-ret is protocol)
81 */
82int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
83{
84 struct udp_sock *up = udp_sk(sk);
85 struct udphdr *uh;
86 struct iphdr *iph;
87 int iphlen, len;
88
89 __u8 *udpdata;
90 __be32 *udpdata32;
91 __u16 encap_type = up->encap_type;
92
93 /* if this is not encapsulated socket, then just return now */
94 if (!encap_type)
95 return 1;
96
97 /* If this is a paged skb, make sure we pull up
98 * whatever data we need to look at. */
99 len = skb->len - sizeof(struct udphdr);
100 if (!pskb_may_pull(skb, sizeof(struct udphdr) + min(len, 8)))
101 return 1;
102
103 /* Now we can get the pointers */
104 uh = udp_hdr(skb);
105 udpdata = (__u8 *)uh + sizeof(struct udphdr);
106 udpdata32 = (__be32 *)udpdata;
107
108 switch (encap_type) {
109 default:
110 case UDP_ENCAP_ESPINUDP:
111 /* Check if this is a keepalive packet. If so, eat it. */
112 if (len == 1 && udpdata[0] == 0xff) {
113 goto drop;
114 } else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) {
115 /* ESP Packet without Non-ESP header */
116 len = sizeof(struct udphdr);
117 } else
118 /* Must be an IKE packet.. pass it through */
119 return 1;
120 break;
121 case UDP_ENCAP_ESPINUDP_NON_IKE:
122 /* Check if this is a keepalive packet. If so, eat it. */
123 if (len == 1 && udpdata[0] == 0xff) {
124 goto drop;
125 } else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) &&
126 udpdata32[0] == 0 && udpdata32[1] == 0) {
127
128 /* ESP Packet with Non-IKE marker */
129 len = sizeof(struct udphdr) + 2 * sizeof(u32);
130 } else
131 /* Must be an IKE packet.. pass it through */
132 return 1;
133 break;
134 }
135
136 /* At this point we are sure that this is an ESPinUDP packet,
137 * so we need to remove 'len' bytes from the packet (the UDP
138 * header and optional ESP marker bytes) and then modify the
139 * protocol to ESP, and then call into the transform receiver.
140 */
141 if (skb_unclone(skb, GFP_ATOMIC))
142 goto drop;
143
144 /* Now we can update and verify the packet length... */
145 iph = ip_hdr(skb);
146 iphlen = iph->ihl << 2;
147 iph->tot_len = htons(ntohs(iph->tot_len) - len);
148 if (skb->len < iphlen + len) {
149 /* packet is too small!?! */
150 goto drop;
151 }
152
153 /* pull the data buffer up to the ESP header and set the
154 * transport header to point to ESP. Keep UDP on the stack
155 * for later.
156 */
157 __skb_pull(skb, len);
158 skb_reset_transport_header(skb);
159
160 /* process ESP */
161 return xfrm4_rcv_encap(skb, IPPROTO_ESP, 0, encap_type);
162
163drop:
164 kfree_skb(skb);
165 return 0;
166}
167
168int xfrm4_rcv(struct sk_buff *skb)
169{
170 return xfrm4_rcv_spi(skb, ip_hdr(skb)->protocol, 0);
171}
172EXPORT_SYMBOL(xfrm4_rcv);