Fix reading broken BER in gcrypt/rsa.c
[tinc] / src / address_cache.c
1 /*
2     address_cache.c -- Manage cache of recently seen addresses
3     Copyright (C) 2018 Guus Sliepen <guus@tinc-vpn.org>
4
5     This program is free software; you can redistribute it and/or modify
6     it under the terms of the GNU General Public License as published by
7     the Free Software Foundation; either version 2 of the License, or
8     (at your option) any later version.
9
10     This program is distributed in the hope that it will be useful,
11     but WITHOUT ANY WARRANTY; without even the implied warranty of
12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13     GNU General Public License for more details.
14
15     You should have received a copy of the GNU General Public License along
16     with this program; if not, write to the Free Software Foundation, Inc.,
17     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
18 */
19
20 #include "system.h"
21
22 #include "address_cache.h"
23 #include "conf.h"
24 #include "names.h"
25 #include "netutl.h"
26 #include "xalloc.h"
27
28 static const unsigned int NOT_CACHED = -1;
29
30 // Find edges pointing to this node, and use them to build a list of unique, known addresses.
31 static struct addrinfo *get_known_addresses(node_t *n) {
32         struct addrinfo *ai = NULL;
33         struct addrinfo *oai = NULL;
34
35         for splay_each(edge_t, e, &n->edge_tree) {
36                 if(!e->reverse) {
37                         continue;
38                 }
39
40                 bool found = false;
41
42                 for(struct addrinfo *aip = ai; aip; aip = aip->ai_next) {
43                         if(!sockaddrcmp(&e->reverse->address, (sockaddr_t *)aip->ai_addr)) {
44                                 found = true;
45                                 break;
46                         }
47                 }
48
49                 if(found) {
50                         continue;
51                 }
52
53                 oai = ai;
54                 ai = xzalloc(sizeof(*ai));
55                 ai->ai_family = e->reverse->address.sa.sa_family;
56                 ai->ai_socktype = SOCK_STREAM;
57                 ai->ai_protocol = IPPROTO_TCP;
58                 ai->ai_addrlen = SALEN(e->reverse->address.sa);
59                 ai->ai_addr = xmalloc(ai->ai_addrlen);
60                 memcpy(ai->ai_addr, &e->reverse->address, ai->ai_addrlen);
61                 ai->ai_next = oai;
62         }
63
64         return ai;
65 }
66
67 static void free_known_addresses(struct addrinfo *ai) {
68         for(struct addrinfo *aip = ai, *next; aip; aip = next) {
69                 next = aip->ai_next;
70                 free(aip->ai_addr);
71                 free(aip);
72         }
73 }
74
75 static unsigned int find_cached(address_cache_t *cache, const sockaddr_t *sa) {
76         for(unsigned int i = 0; i < cache->data.used; i++)
77                 if(!sockaddrcmp(&cache->data.address[i], sa)) {
78                         return i;
79                 }
80
81         return NOT_CACHED;
82 }
83
84 void add_recent_address(address_cache_t *cache, const sockaddr_t *sa) {
85         // Check if it's already cached
86         unsigned int pos = find_cached(cache, sa);
87
88         // It's in the first spot, so nothing to do
89         if(pos == 0) {
90                 return;
91         }
92
93         // Shift everything, move/add the address to the first slot
94         if(pos == NOT_CACHED) {
95                 if(cache->data.used < MAX_CACHED_ADDRESSES) {
96                         cache->data.used++;
97                 }
98
99                 pos = cache->data.used - 1;
100         }
101
102         memmove(&cache->data.address[1], &cache->data.address[0], pos * sizeof(cache->data.address[0]));
103
104         cache->data.address[0] = *sa;
105
106         // Write the cache
107         char fname[PATH_MAX];
108         snprintf(fname, sizeof(fname), "%s" SLASH "cache" SLASH "%s", confbase, cache->node->name);
109         FILE *fp = fopen(fname, "wb");
110
111         if(fp) {
112                 fwrite(&cache->data, sizeof(cache->data), 1, fp);
113                 fclose(fp);
114         }
115 }
116
117 const sockaddr_t *get_recent_address(address_cache_t *cache) {
118         // Check if there is an address in our cache of recently seen addresses
119         if(cache->tried < cache->data.used) {
120                 return &cache->data.address[cache->tried++];
121         }
122
123         // Next, check any recently seen addresses not in our cache
124         while(cache->tried == cache->data.used) {
125                 if(!cache->ai) {
126                         cache->aip = cache->ai = get_known_addresses(cache->node);
127                 }
128
129                 if(cache->ai) {
130                         if(cache->aip) {
131                                 sockaddr_t *sa = (sockaddr_t *)cache->aip->ai_addr;
132                                 cache->aip = cache->aip->ai_next;
133
134                                 if(find_cached(cache, sa) != NOT_CACHED) {
135                                         continue;
136                                 }
137
138                                 return sa;
139                         } else {
140                                 free_known_addresses(cache->ai);
141                                 cache->ai = NULL;
142                         }
143                 }
144
145                 cache->tried++;
146         }
147
148         // Otherwise, check if there are any known Address statements
149         if(!cache->config_tree) {
150                 cache->config_tree = create_configuration();
151                 read_host_config(cache->config_tree, cache->node->name, false);
152                 cache->cfg = lookup_config(cache->config_tree, "Address");
153         }
154
155         while(cache->cfg && !cache->aip) {
156                 char *address, *port;
157
158                 get_config_string(cache->cfg, &address);
159
160                 char *space = strchr(address, ' ');
161
162                 if(space) {
163                         port = xstrdup(space + 1);
164                         *space = 0;
165                 } else {
166                         if(!get_config_string(lookup_config(cache->config_tree, "Port"), &port)) {
167                                 port = xstrdup("655");
168                         }
169                 }
170
171                 if(cache->ai) {
172                         free_known_addresses(cache->ai);
173                 }
174
175                 cache->aip = cache->ai = str2addrinfo(address, port, SOCK_STREAM);
176
177                 if(cache->ai) {
178                         struct addrinfo *ai = NULL;
179
180                         for(; cache->aip; cache->aip = cache->aip->ai_next) {
181                                 struct addrinfo *oai = ai;
182
183                                 ai = xzalloc(sizeof(*ai));
184                                 ai->ai_family = cache->aip->ai_family;
185                                 ai->ai_socktype = cache->aip->ai_socktype;
186                                 ai->ai_protocol = cache->aip->ai_protocol;
187                                 ai->ai_addrlen = cache->aip->ai_addrlen;
188                                 ai->ai_addr = xmalloc(ai->ai_addrlen);
189                                 memcpy(ai->ai_addr, cache->aip->ai_addr, ai->ai_addrlen);
190                                 ai->ai_next = oai;
191                         }
192
193                         freeaddrinfo(cache->ai);
194                         cache->aip = cache->ai = ai;
195                 }
196
197                 free(address);
198                 free(port);
199
200                 cache->cfg = lookup_config_next(cache->config_tree, cache->cfg);
201         }
202
203         if(cache->ai) {
204                 if(cache->aip) {
205                         sockaddr_t *sa = (sockaddr_t *)cache->aip->ai_addr;
206
207                         cache->aip = cache->aip->ai_next;
208                         return sa;
209                 } else {
210                         free_known_addresses(cache->ai);
211                         cache->ai = NULL;
212                 }
213         }
214
215         // We're all out of addresses.
216         exit_configuration(&cache->config_tree);
217         return false;
218 }
219
220 address_cache_t *open_address_cache(node_t *node) {
221         address_cache_t *cache = xmalloc(sizeof(*cache));
222         cache->node = node;
223
224         // Try to open an existing address cache
225         char fname[PATH_MAX];
226         snprintf(fname, sizeof(fname), "%s" SLASH "cache" SLASH "%s", confbase, node->name);
227         FILE *fp = fopen(fname, "rb");
228
229         if(!fp || fread(&cache->data, sizeof(cache->data), 1, fp) != 1 || cache->data.version != ADDRESS_CACHE_VERSION) {
230                 memset(&cache->data, 0, sizeof(cache->data));
231         }
232
233         if(fp) {
234                 fclose(fp);
235         }
236
237         // Ensure we have a valid state
238         cache->config_tree = NULL;
239         cache->cfg = NULL;
240         cache->ai = NULL;
241         cache->aip = NULL;
242         cache->tried = 0;
243         cache->data.version = ADDRESS_CACHE_VERSION;
244
245         if(cache->data.used > MAX_CACHED_ADDRESSES) {
246                 cache->data.used = 0;
247         }
248
249         return cache;
250 }
251
252 void reset_address_cache(address_cache_t *cache, const sockaddr_t *sa) {
253         if(sa) {
254                 add_recent_address(cache, sa);
255         }
256
257         if(cache->config_tree) {
258                 exit_configuration(&cache->config_tree);
259         }
260
261         if(cache->ai) {
262                 free_known_addresses(cache->ai);
263         }
264
265         cache->config_tree = NULL;
266         cache->cfg = NULL;
267         cache->ai = NULL;
268         cache->aip = NULL;
269         cache->tried = 0;
270 }
271
272 void close_address_cache(address_cache_t *cache) {
273         if(cache->config_tree) {
274                 exit_configuration(&cache->config_tree);
275         }
276
277         if(cache->ai) {
278                 free_known_addresses(cache->ai);
279         }
280
281         free(cache);
282 }