2 * Copyright (c) 2007-2013 Nicira, Inc.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of version 2 of the GNU General Public
6 * License as published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
13 * You should have received a copy of the GNU General Public License
14 * along with this program; if not, write to the Free Software
15 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
19 #include <linux/kconfig.h>
20 #if IS_ENABLED(CONFIG_NET_IPGRE_DEMUX)
22 #include <linux/module.h>
24 #include <linux/if_tunnel.h>
25 #include <linux/icmp.h>
28 #include <linux/kernel.h>
29 #include <linux/kmod.h>
30 #include <linux/netdevice.h>
31 #include <linux/skbuff.h>
32 #include <linux/spinlock.h>
36 #include <net/protocol.h>
37 #include <net/route.h>
42 static struct gre_cisco_protocol __rcu *gre_cisco_proto;
44 static void gre_csum_fix(struct sk_buff *skb)
46 struct gre_base_hdr *greh;
48 int gre_offset = skb_transport_offset(skb);
50 greh = (struct gre_base_hdr *)skb_transport_header(skb);
51 options = ((__be32 *)greh + 1);
54 *(__sum16 *)options = csum_fold(skb_checksum(skb, gre_offset,
55 skb->len - gre_offset, 0));
58 struct sk_buff *gre_handle_offloads(struct sk_buff *skb, bool gre_csum)
62 skb_reset_inner_headers(skb);
64 if (skb_is_gso(skb)) {
66 OVS_GSO_CB(skb)->fix_segment = gre_csum_fix;
68 if (skb->ip_summed == CHECKSUM_PARTIAL && gre_csum) {
69 err = skb_checksum_help(skb);
73 } else if (skb->ip_summed != CHECKSUM_PARTIAL)
74 skb->ip_summed = CHECKSUM_NONE;
82 static bool is_gre_gso(struct sk_buff *skb)
84 return skb_is_gso(skb);
87 void gre_build_header(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
90 struct gre_base_hdr *greh;
92 __skb_push(skb, hdr_len);
94 greh = (struct gre_base_hdr *)skb->data;
95 greh->flags = tnl_flags_to_gre_flags(tpi->flags);
96 greh->protocol = tpi->proto;
98 if (tpi->flags & (TUNNEL_KEY | TUNNEL_CSUM | TUNNEL_SEQ)) {
99 __be32 *ptr = (__be32 *)(((u8 *)greh) + hdr_len - 4);
101 if (tpi->flags & TUNNEL_SEQ) {
105 if (tpi->flags & TUNNEL_KEY) {
109 if (tpi->flags & TUNNEL_CSUM && !is_gre_gso(skb)) {
111 *(__sum16 *)ptr = csum_fold(skb_checksum(skb, 0,
117 static __sum16 check_checksum(struct sk_buff *skb)
121 switch (skb->ip_summed) {
122 case CHECKSUM_COMPLETE:
123 csum = csum_fold(skb->csum);
131 csum = __skb_checksum_complete(skb);
132 skb->ip_summed = CHECKSUM_COMPLETE;
139 static int parse_gre_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
142 unsigned int ip_hlen = ip_hdrlen(skb);
143 struct gre_base_hdr *greh;
147 if (unlikely(!pskb_may_pull(skb, sizeof(struct gre_base_hdr))))
150 greh = (struct gre_base_hdr *)(skb_network_header(skb) + ip_hlen);
151 if (unlikely(greh->flags & (GRE_VERSION | GRE_ROUTING)))
154 tpi->flags = gre_flags_to_tnl_flags(greh->flags);
155 hdr_len = ip_gre_calc_hlen(tpi->flags);
157 if (!pskb_may_pull(skb, hdr_len))
160 greh = (struct gre_base_hdr *)(skb_network_header(skb) + ip_hlen);
161 tpi->proto = greh->protocol;
163 options = (__be32 *)(greh + 1);
164 if (greh->flags & GRE_CSUM) {
165 if (check_checksum(skb)) {
172 if (greh->flags & GRE_KEY) {
178 if (unlikely(greh->flags & GRE_SEQ)) {
184 /* WCCP version 1 and 2 protocol decoding.
185 * - Change protocol to IP
186 * - When dealing with WCCPv2, Skip extra 4 bytes in GRE header
188 if (greh->flags == 0 && tpi->proto == htons(ETH_P_WCCP)) {
189 tpi->proto = htons(ETH_P_IP);
190 if ((*(u8 *)options & 0xF0) != 0x40) {
192 if (!pskb_may_pull(skb, hdr_len))
197 return iptunnel_pull_header(skb, hdr_len, tpi->proto);
200 static int gre_cisco_rcv(struct sk_buff *skb)
202 struct tnl_ptk_info tpi;
203 bool csum_err = false;
204 struct gre_cisco_protocol *proto;
207 proto = rcu_dereference(gre_cisco_proto);
211 if (parse_gre_header(skb, &tpi, &csum_err) < 0)
213 proto->handler(skb, &tpi);
223 static const struct gre_protocol ipgre_protocol = {
224 .handler = gre_cisco_rcv,
227 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,37)
228 static const struct gre_protocol __rcu *gre_proto[GREPROTO_MAX] __read_mostly;
230 int gre_add_protocol(const struct gre_protocol *proto, u8 version)
232 if (version >= GREPROTO_MAX)
235 return (cmpxchg((const struct gre_protocol **)&gre_proto[version], NULL, proto) == NULL) ?
239 int gre_del_protocol(const struct gre_protocol *proto, u8 version)
243 if (version >= GREPROTO_MAX)
246 ret = (cmpxchg((const struct gre_protocol **)&gre_proto[version], proto, NULL) == proto) ?
256 static int gre_rcv(struct sk_buff *skb)
258 const struct gre_protocol *proto;
262 if (!pskb_may_pull(skb, 12))
265 ver = skb->data[1] & 0x7f;
266 if (ver >= GREPROTO_MAX)
270 proto = rcu_dereference(gre_proto[ver]);
271 if (!proto || !proto->handler)
273 ret = proto->handler(skb);
284 static const struct net_protocol net_gre_protocol = {
286 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,32)
292 static int gre_compat_init(void)
296 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,37)
297 if (inet_add_protocol(&net_gre_protocol, IPPROTO_GRE) < 0) {
298 pr_err("%s: cannot register gre protocol handler\n", __func__);
302 err = gre_add_protocol(&ipgre_protocol, GREPROTO_CISCO);
304 pr_warn("%s: cannot register gre_cisco protocol handler\n", __func__);
306 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,37)
307 inet_del_protocol(&net_gre_protocol, IPPROTO_GRE);
314 static int gre_compat_exit(void)
318 ret = gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO);
322 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,37)
323 ret = inet_del_protocol(&net_gre_protocol, IPPROTO_GRE);
330 int gre_cisco_register(struct gre_cisco_protocol *newp)
334 err = gre_compat_init();
338 return (cmpxchg((struct gre_cisco_protocol **)&gre_cisco_proto, NULL, newp) == NULL) ?
342 int gre_cisco_unregister(struct gre_cisco_protocol *proto)
346 ret = (cmpxchg((struct gre_cisco_protocol **)&gre_cisco_proto, proto, NULL) == proto) ?
353 ret = gre_compat_exit();
357 #endif /* CONFIG_NET_IPGRE_DEMUX */