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Diffstat (limited to 'net/ipv4/gre_demux.c')
-rw-r--r--net/ipv4/gre_demux.c235
1 files changed, 1 insertions, 234 deletions
diff --git a/net/ipv4/gre_demux.c b/net/ipv4/gre_demux.c
index 4a7b5b2a1ce3..d9c552a721fc 100644
--- a/net/ipv4/gre_demux.c
+++ b/net/ipv4/gre_demux.c
@@ -31,7 +31,6 @@
31#include <net/xfrm.h> 31#include <net/xfrm.h>
32 32
33static const struct gre_protocol __rcu *gre_proto[GREPROTO_MAX] __read_mostly; 33static const struct gre_protocol __rcu *gre_proto[GREPROTO_MAX] __read_mostly;
34static struct gre_cisco_protocol __rcu *gre_cisco_proto_list[GRE_IP_PROTO_MAX];
35 34
36int gre_add_protocol(const struct gre_protocol *proto, u8 version) 35int gre_add_protocol(const struct gre_protocol *proto, u8 version)
37{ 36{
@@ -61,197 +60,6 @@ int gre_del_protocol(const struct gre_protocol *proto, u8 version)
61} 60}
62EXPORT_SYMBOL_GPL(gre_del_protocol); 61EXPORT_SYMBOL_GPL(gre_del_protocol);
63 62
64void gre_build_header(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
65 int hdr_len)
66{
67 struct gre_base_hdr *greh;
68
69 skb_push(skb, hdr_len);
70
71 skb_reset_transport_header(skb);
72 greh = (struct gre_base_hdr *)skb->data;
73 greh->flags = tnl_flags_to_gre_flags(tpi->flags);
74 greh->protocol = tpi->proto;
75
76 if (tpi->flags&(TUNNEL_KEY|TUNNEL_CSUM|TUNNEL_SEQ)) {
77 __be32 *ptr = (__be32 *)(((u8 *)greh) + hdr_len - 4);
78
79 if (tpi->flags&TUNNEL_SEQ) {
80 *ptr = tpi->seq;
81 ptr--;
82 }
83 if (tpi->flags&TUNNEL_KEY) {
84 *ptr = tpi->key;
85 ptr--;
86 }
87 if (tpi->flags&TUNNEL_CSUM &&
88 !(skb_shinfo(skb)->gso_type &
89 (SKB_GSO_GRE|SKB_GSO_GRE_CSUM))) {
90 *ptr = 0;
91 *(__sum16 *)ptr = csum_fold(skb_checksum(skb, 0,
92 skb->len, 0));
93 }
94 }
95}
96EXPORT_SYMBOL_GPL(gre_build_header);
97
98static int parse_gre_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
99 bool *csum_err)
100{
101 const struct gre_base_hdr *greh;
102 __be32 *options;
103 int hdr_len;
104
105 if (unlikely(!pskb_may_pull(skb, sizeof(struct gre_base_hdr))))
106 return -EINVAL;
107
108 greh = (struct gre_base_hdr *)skb_transport_header(skb);
109 if (unlikely(greh->flags & (GRE_VERSION | GRE_ROUTING)))
110 return -EINVAL;
111
112 tpi->flags = gre_flags_to_tnl_flags(greh->flags);
113 hdr_len = ip_gre_calc_hlen(tpi->flags);
114
115 if (!pskb_may_pull(skb, hdr_len))
116 return -EINVAL;
117
118 greh = (struct gre_base_hdr *)skb_transport_header(skb);
119 tpi->proto = greh->protocol;
120
121 options = (__be32 *)(greh + 1);
122 if (greh->flags & GRE_CSUM) {
123 if (skb_checksum_simple_validate(skb)) {
124 *csum_err = true;
125 return -EINVAL;
126 }
127
128 skb_checksum_try_convert(skb, IPPROTO_GRE, 0,
129 null_compute_pseudo);
130
131 options++;
132 }
133
134 if (greh->flags & GRE_KEY) {
135 tpi->key = *options;
136 options++;
137 } else
138 tpi->key = 0;
139
140 if (unlikely(greh->flags & GRE_SEQ)) {
141 tpi->seq = *options;
142 options++;
143 } else
144 tpi->seq = 0;
145
146 /* WCCP version 1 and 2 protocol decoding.
147 * - Change protocol to IP
148 * - When dealing with WCCPv2, Skip extra 4 bytes in GRE header
149 */
150 if (greh->flags == 0 && tpi->proto == htons(ETH_P_WCCP)) {
151 tpi->proto = htons(ETH_P_IP);
152 if ((*(u8 *)options & 0xF0) != 0x40) {
153 hdr_len += 4;
154 if (!pskb_may_pull(skb, hdr_len))
155 return -EINVAL;
156 }
157 }
158
159 return iptunnel_pull_header(skb, hdr_len, tpi->proto);
160}
161
162static int gre_cisco_rcv(struct sk_buff *skb)
163{
164 struct tnl_ptk_info tpi;
165 int i;
166 bool csum_err = false;
167
168#ifdef CONFIG_NET_IPGRE_BROADCAST
169 if (ipv4_is_multicast(ip_hdr(skb)->daddr)) {
170 /* Looped back packet, drop it! */
171 if (rt_is_output_route(skb_rtable(skb)))
172 goto drop;
173 }
174#endif
175
176 if (parse_gre_header(skb, &tpi, &csum_err) < 0)
177 goto drop;
178
179 rcu_read_lock();
180 for (i = 0; i < GRE_IP_PROTO_MAX; i++) {
181 struct gre_cisco_protocol *proto;
182 int ret;
183
184 proto = rcu_dereference(gre_cisco_proto_list[i]);
185 if (!proto)
186 continue;
187 ret = proto->handler(skb, &tpi);
188 if (ret == PACKET_RCVD) {
189 rcu_read_unlock();
190 return 0;
191 }
192 }
193 rcu_read_unlock();
194
195 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
196drop:
197 kfree_skb(skb);
198 return 0;
199}
200
201static void gre_cisco_err(struct sk_buff *skb, u32 info)
202{
203 /* All the routers (except for Linux) return only
204 * 8 bytes of packet payload. It means, that precise relaying of
205 * ICMP in the real Internet is absolutely infeasible.
206 *
207 * Moreover, Cisco "wise men" put GRE key to the third word
208 * in GRE header. It makes impossible maintaining even soft
209 * state for keyed
210 * GRE tunnels with enabled checksum. Tell them "thank you".
211 *
212 * Well, I wonder, rfc1812 was written by Cisco employee,
213 * what the hell these idiots break standards established
214 * by themselves???
215 */
216
217 const int type = icmp_hdr(skb)->type;
218 const int code = icmp_hdr(skb)->code;
219 struct tnl_ptk_info tpi;
220 bool csum_err = false;
221 int i;
222
223 if (parse_gre_header(skb, &tpi, &csum_err)) {
224 if (!csum_err) /* ignore csum errors. */
225 return;
226 }
227
228 if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
229 ipv4_update_pmtu(skb, dev_net(skb->dev), info,
230 skb->dev->ifindex, 0, IPPROTO_GRE, 0);
231 return;
232 }
233 if (type == ICMP_REDIRECT) {
234 ipv4_redirect(skb, dev_net(skb->dev), skb->dev->ifindex, 0,
235 IPPROTO_GRE, 0);
236 return;
237 }
238
239 rcu_read_lock();
240 for (i = 0; i < GRE_IP_PROTO_MAX; i++) {
241 struct gre_cisco_protocol *proto;
242
243 proto = rcu_dereference(gre_cisco_proto_list[i]);
244 if (!proto)
245 continue;
246
247 if (proto->err_handler(skb, info, &tpi) == PACKET_RCVD)
248 goto out;
249
250 }
251out:
252 rcu_read_unlock();
253}
254
255static int gre_rcv(struct sk_buff *skb) 63static int gre_rcv(struct sk_buff *skb)
256{ 64{
257 const struct gre_protocol *proto; 65 const struct gre_protocol *proto;
@@ -302,60 +110,19 @@ static const struct net_protocol net_gre_protocol = {
302 .netns_ok = 1, 110 .netns_ok = 1,
303}; 111};
304 112
305static const struct gre_protocol ipgre_protocol = {
306 .handler = gre_cisco_rcv,
307 .err_handler = gre_cisco_err,
308};
309
310int gre_cisco_register(struct gre_cisco_protocol *newp)
311{
312 struct gre_cisco_protocol **proto = (struct gre_cisco_protocol **)
313 &gre_cisco_proto_list[newp->priority];
314
315 return (cmpxchg(proto, NULL, newp) == NULL) ? 0 : -EBUSY;
316}
317EXPORT_SYMBOL_GPL(gre_cisco_register);
318
319int gre_cisco_unregister(struct gre_cisco_protocol *del_proto)
320{
321 struct gre_cisco_protocol **proto = (struct gre_cisco_protocol **)
322 &gre_cisco_proto_list[del_proto->priority];
323 int ret;
324
325 ret = (cmpxchg(proto, del_proto, NULL) == del_proto) ? 0 : -EINVAL;
326
327 if (ret)
328 return ret;
329
330 synchronize_net();
331 return 0;
332}
333EXPORT_SYMBOL_GPL(gre_cisco_unregister);
334
335static int __init gre_init(void) 113static int __init gre_init(void)
336{ 114{
337 pr_info("GRE over IPv4 demultiplexor driver\n"); 115 pr_info("GRE over IPv4 demultiplexor driver\n");
338 116
339 if (inet_add_protocol(&net_gre_protocol, IPPROTO_GRE) < 0) { 117 if (inet_add_protocol(&net_gre_protocol, IPPROTO_GRE) < 0) {
340 pr_err("can't add protocol\n"); 118 pr_err("can't add protocol\n");
341 goto err; 119 return -EAGAIN;
342 }
343
344 if (gre_add_protocol(&ipgre_protocol, GREPROTO_CISCO) < 0) {
345 pr_info("%s: can't add ipgre handler\n", __func__);
346 goto err_gre;
347 } 120 }
348
349 return 0; 121 return 0;
350err_gre:
351 inet_del_protocol(&net_gre_protocol, IPPROTO_GRE);
352err:
353 return -EAGAIN;
354} 122}
355 123
356static void __exit gre_exit(void) 124static void __exit gre_exit(void)
357{ 125{
358 gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO);
359 inet_del_protocol(&net_gre_protocol, IPPROTO_GRE); 126 inet_del_protocol(&net_gre_protocol, IPPROTO_GRE);
360} 127}
361 128
generated by cgit v1.2.2 (git 2.25.0) at 2025-02-26 01:04:15 -0500