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27#include <linux/module.h>
28#include <linux/types.h>
29#include <linux/timer.h>
30#include <linux/list.h>
31#include <linux/seq_file.h>
32#include <linux/in.h>
33#include <linux/netdevice.h>
34#include <linux/skbuff.h>
35#include <linux/slab.h>
36#include <net/dst.h>
37#include <net/net_namespace.h>
38#include <net/netns/generic.h>
39#include <net/netfilter/nf_conntrack_l4proto.h>
40#include <net/netfilter/nf_conntrack_helper.h>
41#include <net/netfilter/nf_conntrack_core.h>
42#include <linux/netfilter/nf_conntrack_proto_gre.h>
43#include <linux/netfilter/nf_conntrack_pptp.h>
44
45enum grep_conntrack {
46 GRE_CT_UNREPLIED,
47 GRE_CT_REPLIED,
48 GRE_CT_MAX
49};
50
51static unsigned int gre_timeouts[GRE_CT_MAX] = {
52 [GRE_CT_UNREPLIED] = 30*HZ,
53 [GRE_CT_REPLIED] = 180*HZ,
54};
55
56static int proto_gre_net_id __read_mostly;
57struct netns_proto_gre {
58 struct nf_proto_net nf;
59 rwlock_t keymap_lock;
60 struct list_head keymap_list;
61 unsigned int gre_timeouts[GRE_CT_MAX];
62};
63
64static inline struct netns_proto_gre *gre_pernet(struct net *net)
65{
66 return net_generic(net, proto_gre_net_id);
67}
68
69static void nf_ct_gre_keymap_flush(struct net *net)
70{
71 struct netns_proto_gre *net_gre = gre_pernet(net);
72 struct nf_ct_gre_keymap *km, *tmp;
73
74 write_lock_bh(&net_gre->keymap_lock);
75 list_for_each_entry_safe(km, tmp, &net_gre->keymap_list, list) {
76 list_del(&km->list);
77 kfree(km);
78 }
79 write_unlock_bh(&net_gre->keymap_lock);
80}
81
82static inline int gre_key_cmpfn(const struct nf_ct_gre_keymap *km,
83 const struct nf_conntrack_tuple *t)
84{
85 return km->tuple.src.l3num == t->src.l3num &&
86 !memcmp(&km->tuple.src.u3, &t->src.u3, sizeof(t->src.u3)) &&
87 !memcmp(&km->tuple.dst.u3, &t->dst.u3, sizeof(t->dst.u3)) &&
88 km->tuple.dst.protonum == t->dst.protonum &&
89 km->tuple.dst.u.all == t->dst.u.all;
90}
91
92
93static __be16 gre_keymap_lookup(struct net *net, struct nf_conntrack_tuple *t)
94{
95 struct netns_proto_gre *net_gre = gre_pernet(net);
96 struct nf_ct_gre_keymap *km;
97 __be16 key = 0;
98
99 read_lock_bh(&net_gre->keymap_lock);
100 list_for_each_entry(km, &net_gre->keymap_list, list) {
101 if (gre_key_cmpfn(km, t)) {
102 key = km->tuple.src.u.gre.key;
103 break;
104 }
105 }
106 read_unlock_bh(&net_gre->keymap_lock);
107
108 pr_debug("lookup src key 0x%x for ", key);
109 nf_ct_dump_tuple(t);
110
111 return key;
112}
113
114
115int nf_ct_gre_keymap_add(struct nf_conn *ct, enum ip_conntrack_dir dir,
116 struct nf_conntrack_tuple *t)
117{
118 struct net *net = nf_ct_net(ct);
119 struct netns_proto_gre *net_gre = gre_pernet(net);
120 struct nf_ct_pptp_master *ct_pptp_info = nfct_help_data(ct);
121 struct nf_ct_gre_keymap **kmp, *km;
122
123 kmp = &ct_pptp_info->keymap[dir];
124 if (*kmp) {
125
126 read_lock_bh(&net_gre->keymap_lock);
127 list_for_each_entry(km, &net_gre->keymap_list, list) {
128 if (gre_key_cmpfn(km, t) && km == *kmp) {
129 read_unlock_bh(&net_gre->keymap_lock);
130 return 0;
131 }
132 }
133 read_unlock_bh(&net_gre->keymap_lock);
134 pr_debug("trying to override keymap_%s for ct %p\n",
135 dir == IP_CT_DIR_REPLY ? "reply" : "orig", ct);
136 return -EEXIST;
137 }
138
139 km = kmalloc(sizeof(*km), GFP_ATOMIC);
140 if (!km)
141 return -ENOMEM;
142 memcpy(&km->tuple, t, sizeof(*t));
143 *kmp = km;
144
145 pr_debug("adding new entry %p: ", km);
146 nf_ct_dump_tuple(&km->tuple);
147
148 write_lock_bh(&net_gre->keymap_lock);
149 list_add_tail(&km->list, &net_gre->keymap_list);
150 write_unlock_bh(&net_gre->keymap_lock);
151
152 return 0;
153}
154EXPORT_SYMBOL_GPL(nf_ct_gre_keymap_add);
155
156
157void nf_ct_gre_keymap_destroy(struct nf_conn *ct)
158{
159 struct net *net = nf_ct_net(ct);
160 struct netns_proto_gre *net_gre = gre_pernet(net);
161 struct nf_ct_pptp_master *ct_pptp_info = nfct_help_data(ct);
162 enum ip_conntrack_dir dir;
163
164 pr_debug("entering for ct %p\n", ct);
165
166 write_lock_bh(&net_gre->keymap_lock);
167 for (dir = IP_CT_DIR_ORIGINAL; dir < IP_CT_DIR_MAX; dir++) {
168 if (ct_pptp_info->keymap[dir]) {
169 pr_debug("removing %p from list\n",
170 ct_pptp_info->keymap[dir]);
171 list_del(&ct_pptp_info->keymap[dir]->list);
172 kfree(ct_pptp_info->keymap[dir]);
173 ct_pptp_info->keymap[dir] = NULL;
174 }
175 }
176 write_unlock_bh(&net_gre->keymap_lock);
177}
178EXPORT_SYMBOL_GPL(nf_ct_gre_keymap_destroy);
179
180
181
182
183static bool gre_invert_tuple(struct nf_conntrack_tuple *tuple,
184 const struct nf_conntrack_tuple *orig)
185{
186 tuple->dst.u.gre.key = orig->src.u.gre.key;
187 tuple->src.u.gre.key = orig->dst.u.gre.key;
188 return true;
189}
190
191
192static bool gre_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff,
193 struct net *net, struct nf_conntrack_tuple *tuple)
194{
195 const struct pptp_gre_header *pgrehdr;
196 struct pptp_gre_header _pgrehdr;
197 __be16 srckey;
198 const struct gre_base_hdr *grehdr;
199 struct gre_base_hdr _grehdr;
200
201
202 grehdr = skb_header_pointer(skb, dataoff, sizeof(_grehdr), &_grehdr);
203 if (!grehdr || (grehdr->flags & GRE_VERSION) != GRE_VERSION_1) {
204
205 tuple->src.u.all = 0;
206 tuple->dst.u.all = 0;
207 return true;
208 }
209
210
211 pgrehdr = skb_header_pointer(skb, dataoff, 8, &_pgrehdr);
212 if (!pgrehdr)
213 return true;
214
215 if (grehdr->protocol != GRE_PROTO_PPP) {
216 pr_debug("Unsupported GRE proto(0x%x)\n", ntohs(grehdr->protocol));
217 return false;
218 }
219
220 tuple->dst.u.gre.key = pgrehdr->call_id;
221 srckey = gre_keymap_lookup(net, tuple);
222 tuple->src.u.gre.key = srckey;
223
224 return true;
225}
226
227
228static void gre_print_tuple(struct seq_file *s,
229 const struct nf_conntrack_tuple *tuple)
230{
231 seq_printf(s, "srckey=0x%x dstkey=0x%x ",
232 ntohs(tuple->src.u.gre.key),
233 ntohs(tuple->dst.u.gre.key));
234}
235
236
237static void gre_print_conntrack(struct seq_file *s, struct nf_conn *ct)
238{
239 seq_printf(s, "timeout=%u, stream_timeout=%u ",
240 (ct->proto.gre.timeout / HZ),
241 (ct->proto.gre.stream_timeout / HZ));
242}
243
244static unsigned int *gre_get_timeouts(struct net *net)
245{
246 return gre_pernet(net)->gre_timeouts;
247}
248
249
250static int gre_packet(struct nf_conn *ct,
251 const struct sk_buff *skb,
252 unsigned int dataoff,
253 enum ip_conntrack_info ctinfo,
254 u_int8_t pf,
255 unsigned int hooknum,
256 unsigned int *timeouts)
257{
258
259
260 if (ct->status & IPS_SEEN_REPLY) {
261 nf_ct_refresh_acct(ct, ctinfo, skb,
262 ct->proto.gre.stream_timeout);
263
264 if (!test_and_set_bit(IPS_ASSURED_BIT, &ct->status))
265 nf_conntrack_event_cache(IPCT_ASSURED, ct);
266 } else
267 nf_ct_refresh_acct(ct, ctinfo, skb,
268 ct->proto.gre.timeout);
269
270 return NF_ACCEPT;
271}
272
273
274static bool gre_new(struct nf_conn *ct, const struct sk_buff *skb,
275 unsigned int dataoff, unsigned int *timeouts)
276{
277 pr_debug(": ");
278 nf_ct_dump_tuple(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
279
280
281
282 ct->proto.gre.stream_timeout = timeouts[GRE_CT_REPLIED];
283 ct->proto.gre.timeout = timeouts[GRE_CT_UNREPLIED];
284
285 return true;
286}
287
288
289
290static void gre_destroy(struct nf_conn *ct)
291{
292 struct nf_conn *master = ct->master;
293 pr_debug(" entering\n");
294
295 if (!master)
296 pr_debug("no master !?!\n");
297 else
298 nf_ct_gre_keymap_destroy(master);
299}
300
301#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
302
303#include <linux/netfilter/nfnetlink.h>
304#include <linux/netfilter/nfnetlink_cttimeout.h>
305
306static int gre_timeout_nlattr_to_obj(struct nlattr *tb[],
307 struct net *net, void *data)
308{
309 unsigned int *timeouts = data;
310 struct netns_proto_gre *net_gre = gre_pernet(net);
311
312
313 timeouts[GRE_CT_UNREPLIED] = net_gre->gre_timeouts[GRE_CT_UNREPLIED];
314 timeouts[GRE_CT_REPLIED] = net_gre->gre_timeouts[GRE_CT_REPLIED];
315
316 if (tb[CTA_TIMEOUT_GRE_UNREPLIED]) {
317 timeouts[GRE_CT_UNREPLIED] =
318 ntohl(nla_get_be32(tb[CTA_TIMEOUT_GRE_UNREPLIED])) * HZ;
319 }
320 if (tb[CTA_TIMEOUT_GRE_REPLIED]) {
321 timeouts[GRE_CT_REPLIED] =
322 ntohl(nla_get_be32(tb[CTA_TIMEOUT_GRE_REPLIED])) * HZ;
323 }
324 return 0;
325}
326
327static int
328gre_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
329{
330 const unsigned int *timeouts = data;
331
332 if (nla_put_be32(skb, CTA_TIMEOUT_GRE_UNREPLIED,
333 htonl(timeouts[GRE_CT_UNREPLIED] / HZ)) ||
334 nla_put_be32(skb, CTA_TIMEOUT_GRE_REPLIED,
335 htonl(timeouts[GRE_CT_REPLIED] / HZ)))
336 goto nla_put_failure;
337 return 0;
338
339nla_put_failure:
340 return -ENOSPC;
341}
342
343static const struct nla_policy
344gre_timeout_nla_policy[CTA_TIMEOUT_GRE_MAX+1] = {
345 [CTA_TIMEOUT_GRE_UNREPLIED] = { .type = NLA_U32 },
346 [CTA_TIMEOUT_GRE_REPLIED] = { .type = NLA_U32 },
347};
348#endif
349
350static int gre_init_net(struct net *net, u_int16_t proto)
351{
352 struct netns_proto_gre *net_gre = gre_pernet(net);
353 int i;
354
355 rwlock_init(&net_gre->keymap_lock);
356 INIT_LIST_HEAD(&net_gre->keymap_list);
357 for (i = 0; i < GRE_CT_MAX; i++)
358 net_gre->gre_timeouts[i] = gre_timeouts[i];
359
360 return 0;
361}
362
363
364static struct nf_conntrack_l4proto nf_conntrack_l4proto_gre4 __read_mostly = {
365 .l3proto = AF_INET,
366 .l4proto = IPPROTO_GRE,
367 .name = "gre",
368 .pkt_to_tuple = gre_pkt_to_tuple,
369 .invert_tuple = gre_invert_tuple,
370 .print_tuple = gre_print_tuple,
371 .print_conntrack = gre_print_conntrack,
372 .get_timeouts = gre_get_timeouts,
373 .packet = gre_packet,
374 .new = gre_new,
375 .destroy = gre_destroy,
376 .me = THIS_MODULE,
377#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
378 .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
379 .nlattr_tuple_size = nf_ct_port_nlattr_tuple_size,
380 .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
381 .nla_policy = nf_ct_port_nla_policy,
382#endif
383#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
384 .ctnl_timeout = {
385 .nlattr_to_obj = gre_timeout_nlattr_to_obj,
386 .obj_to_nlattr = gre_timeout_obj_to_nlattr,
387 .nlattr_max = CTA_TIMEOUT_GRE_MAX,
388 .obj_size = sizeof(unsigned int) * GRE_CT_MAX,
389 .nla_policy = gre_timeout_nla_policy,
390 },
391#endif
392 .net_id = &proto_gre_net_id,
393 .init_net = gre_init_net,
394};
395
396static int proto_gre_net_init(struct net *net)
397{
398 int ret = 0;
399 ret = nf_ct_l4proto_pernet_register(net, &nf_conntrack_l4proto_gre4);
400 if (ret < 0)
401 pr_err("nf_conntrack_gre4: pernet registration failed.\n");
402 return ret;
403}
404
405static void proto_gre_net_exit(struct net *net)
406{
407 nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_gre4);
408 nf_ct_gre_keymap_flush(net);
409}
410
411static struct pernet_operations proto_gre_net_ops = {
412 .init = proto_gre_net_init,
413 .exit = proto_gre_net_exit,
414 .id = &proto_gre_net_id,
415 .size = sizeof(struct netns_proto_gre),
416};
417
418static int __init nf_ct_proto_gre_init(void)
419{
420 int ret;
421
422 ret = register_pernet_subsys(&proto_gre_net_ops);
423 if (ret < 0)
424 goto out_pernet;
425
426 ret = nf_ct_l4proto_register(&nf_conntrack_l4proto_gre4);
427 if (ret < 0)
428 goto out_gre4;
429
430 return 0;
431out_gre4:
432 unregister_pernet_subsys(&proto_gre_net_ops);
433out_pernet:
434 return ret;
435}
436
437static void __exit nf_ct_proto_gre_fini(void)
438{
439 nf_ct_l4proto_unregister(&nf_conntrack_l4proto_gre4);
440 unregister_pernet_subsys(&proto_gre_net_ops);
441}
442
443module_init(nf_ct_proto_gre_init);
444module_exit(nf_ct_proto_gre_fini);
445
446MODULE_LICENSE("GPL");
447
