1 // SPDX-License-Identifier: GPL-2.0
6 * YOSHIFUJI Hideaki @USAGI
7 * Split up af-specific portion
8 * Derek Atkins <derek@ihtfp.com>
9 * Add Encapsulation support
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>
20 #include <net/protocol.h>
23 static int xfrm4_rcv_encap_finish2(struct net *net, struct sock *sk,
26 return dst_input(skb);
29 static inline int xfrm4_rcv_encap_finish(struct net *net, struct sock *sk,
33 const struct iphdr *iph = ip_hdr(skb);
35 if (ip_route_input_noref(skb, iph->daddr, iph->saddr,
40 if (xfrm_trans_queue(skb, xfrm4_rcv_encap_finish2))
49 int xfrm4_transport_finish(struct sk_buff *skb, int async)
51 struct xfrm_offload *xo = xfrm_offload(skb);
52 struct iphdr *iph = ip_hdr(skb);
54 iph->protocol = XFRM_MODE_SKB_CB(skb)->protocol;
56 #ifndef CONFIG_NETFILTER
58 return -iph->protocol;
61 __skb_push(skb, skb->data - skb_network_header(skb));
62 iph->tot_len = htons(skb->len);
65 if (xo && (xo->flags & XFRM_GRO)) {
66 skb_mac_header_rebuild(skb);
67 skb_reset_transport_header(skb);
71 NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING,
72 dev_net(skb->dev), NULL, skb, skb->dev, NULL,
73 xfrm4_rcv_encap_finish);
77 static int __xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb, bool pull)
79 struct udp_sock *up = udp_sk(sk);
87 encap_type = READ_ONCE(up->encap_type);
88 /* if this is not encapsulated socket, then just return now */
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)))
98 /* Now we can get the pointers */
100 udpdata = (__u8 *)uh + sizeof(struct udphdr);
101 udpdata32 = (__be32 *)udpdata;
103 switch (encap_type) {
105 case UDP_ENCAP_ESPINUDP:
106 /* Check if this is a keepalive packet. If so, eat it. */
107 if (len == 1 && udpdata[0] == 0xff) {
109 } else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) {
110 /* ESP Packet without Non-ESP header */
111 len = sizeof(struct udphdr);
113 /* Must be an IKE packet.. pass it through */
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) {
120 } else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) &&
121 udpdata32[0] == 0 && udpdata32[1] == 0) {
123 /* ESP Packet with Non-IKE marker */
124 len = sizeof(struct udphdr) + 2 * sizeof(u32);
126 /* Must be an IKE packet.. pass it through */
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.
136 if (skb_unclone(skb, GFP_ATOMIC))
139 /* Now we can update and verify the packet length... */
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!?! */
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
153 __skb_pull(skb, len);
154 skb_reset_transport_header(skb);
156 skb_set_transport_header(skb, len);
163 /* If it's a keepalive packet, then just eat it.
164 * If it's an encapsulated packet, then pass it to the
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)
170 int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
174 ret = __xfrm4_udp_encap_rcv(sk, skb, true);
176 return xfrm4_rcv_encap(skb, IPPROTO_ESP, 0,
177 udp_sk(sk)->encap_type);
186 EXPORT_SYMBOL(xfrm4_udp_encap_rcv);
188 struct sk_buff *xfrm4_gro_udp_encap_rcv(struct sock *sk, struct list_head *head,
191 int offset = skb_gro_offset(skb);
192 const struct net_offload *ops;
193 struct sk_buff *pp = NULL;
196 offset = offset - sizeof(struct udphdr);
198 if (!pskb_pull(skb, offset))
202 ops = rcu_dereference(inet_offloads[IPPROTO_ESP]);
203 if (!ops || !ops->callbacks.gro_receive)
206 ret = __xfrm4_udp_encap_rcv(sk, skb, false);
210 skb_push(skb, offset);
211 NAPI_GRO_CB(skb)->proto = IPPROTO_UDP;
213 pp = call_gro_receive(ops->callbacks.gro_receive, head, skb);
220 skb_push(skb, offset);
221 NAPI_GRO_CB(skb)->same_flow = 0;
222 NAPI_GRO_CB(skb)->flush = 1;
226 EXPORT_SYMBOL(xfrm4_gro_udp_encap_rcv);
228 int xfrm4_rcv(struct sk_buff *skb)
230 return xfrm4_rcv_spi(skb, ip_hdr(skb)->protocol, 0);
232 EXPORT_SYMBOL(xfrm4_rcv);