--- /dev/null
+/*
+ address_cache.c -- Manage cache of recently seen addresses
+ Copyright (C) 2018 Guus Sliepen <guus@tinc-vpn.org>
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along
+ with this program; if not, write to the Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#include "system.h"
+
+#include "address_cache.h"
+#include "conf.h"
+#include "names.h"
+#include "netutl.h"
+#include "xalloc.h"
+
+static const unsigned int NOT_CACHED = -1;
+
+// Find edges pointing to this node, and use them to build a list of unique, known addresses.
+static struct addrinfo *get_known_addresses(node_t *n) {
+ struct addrinfo *ai = NULL;
+ struct addrinfo *oai = NULL;
+
+ for splay_each(edge_t, e, n->edge_tree) {
+ if(!e->reverse) {
+ continue;
+ }
+
+ bool found = false;
+
+ for(struct addrinfo *aip = ai; aip; aip = aip->ai_next) {
+ if(!sockaddrcmp(&e->reverse->address, (sockaddr_t *)aip->ai_addr)) {
+ found = true;
+ break;
+ }
+ }
+
+ if(found) {
+ continue;
+ }
+
+ oai = ai;
+ ai = xzalloc(sizeof(*ai));
+ ai->ai_family = e->reverse->address.sa.sa_family;
+ ai->ai_socktype = SOCK_STREAM;
+ ai->ai_protocol = IPPROTO_TCP;
+ ai->ai_addrlen = SALEN(e->reverse->address.sa);
+ ai->ai_addr = xmalloc(ai->ai_addrlen);
+ memcpy(ai->ai_addr, &e->reverse->address, ai->ai_addrlen);
+ ai->ai_next = oai;
+ }
+
+ return ai;
+}
+
+static void free_known_addresses(struct addrinfo *ai) {
+ for(struct addrinfo *aip = ai, *next; aip; aip = next) {
+ next = aip->ai_next;
+ free(aip);
+ }
+}
+
+static unsigned int find_cached(address_cache_t *cache, const sockaddr_t *sa) {
+ for(unsigned int i = 0; i < cache->data.used; i++)
+ if(!sockaddrcmp(&cache->data.address[i], sa)) {
+ return i;
+ }
+
+ return NOT_CACHED;
+}
+
+void add_recent_address(address_cache_t *cache, const sockaddr_t *sa) {
+ // Check if it's already cached
+ unsigned int pos = find_cached(cache, sa);
+
+ // It's in the first spot, so nothing to do
+ if (pos == 0) {
+ return;
+ }
+
+ // Shift everything, move/add the address to the first slot
+ if(pos == NOT_CACHED) {
+ if(cache->data.used < MAX_CACHED_ADDRESSES)
+ cache->data.used++;
+ pos = cache->data.used - 1;
+ }
+
+ memmove(&cache->data.address[1], &cache->data.address[0], pos * sizeof(cache->data.address[0]));
+
+ cache->data.address[0] = *sa;
+
+ // Write the cache
+ char fname[PATH_MAX];
+ snprintf(fname, sizeof(fname), "%s" SLASH "cache" SLASH "%s", confbase, cache->node->name);
+ FILE *fp = fopen(fname, "wb");
+
+ if(fp) {
+ fprintf(stderr, "Writing cache to %s\n", fname);
+ fwrite(&cache->data, sizeof(cache->data), 1, fp);
+ fclose(fp);
+ }
+}
+
+const sockaddr_t *get_recent_address(address_cache_t *cache) {
+ // Check if there is an address in our cache of recently seen addresses
+ if(cache->tried < cache->data.used) {
+ return &cache->data.address[cache->tried++];
+ }
+
+ // Next, check any recently seen addresses not in our cache
+ while(cache->tried == cache->data.used) {
+ if(!cache->ai) {
+ cache->aip = cache->ai = get_known_addresses(cache->node);
+ }
+
+ if(cache->ai) {
+ if(cache->aip) {
+ sockaddr_t *sa = (sockaddr_t *)cache->aip;
+
+ if(find_cached(cache, sa) != NOT_CACHED) {
+ continue;
+ }
+
+ cache->aip = cache->aip->ai_next;
+ return sa;
+ } else {
+ free_known_addresses(cache->ai);
+ cache->ai = NULL;
+ }
+ }
+
+ cache->tried++;
+ }
+
+ // Otherwise, check if there are any known Address statements
+ if(!cache->config_tree) {
+ init_configuration(&cache->config_tree);
+ read_host_config(cache->config_tree, cache->node->name, false);
+ cache->cfg = lookup_config(cache->config_tree, "Address");
+ }
+
+ while(cache->cfg && !cache->ai) {
+ char *address, *port;
+
+ get_config_string(cache->cfg, &address);
+
+ char *space = strchr(address, ' ');
+
+ if(space) {
+ port = xstrdup(space + 1);
+ *space = 0;
+ } else {
+ if(!get_config_string(lookup_config(cache->config_tree, "Port"), &port)) {
+ port = xstrdup("655");
+ }
+ }
+
+ cache->aip = cache->ai = str2addrinfo(address, port, SOCK_STREAM);
+ free(address);
+ free(port);
+
+ cache->cfg = lookup_config_next(cache->config_tree, cache->cfg);
+ }
+
+ if(cache->aip) {
+ sockaddr_t *sa = (sockaddr_t *)cache->aip->ai_addr;
+ cache->aip = cache->aip->ai_next;
+
+ if(!cache->aip) {
+ freeaddrinfo(cache->aip);
+ cache->aip = NULL;
+ }
+
+ return sa;
+ }
+
+ // We're all out of addresses.
+ exit_configuration(&cache->config_tree);
+ return false;
+}
+
+address_cache_t *open_address_cache(node_t *node) {
+ address_cache_t *cache = xmalloc(sizeof(*cache));
+ cache->node = node;
+
+ // Try to open an existing address cache
+ char fname[PATH_MAX];
+ snprintf(fname, sizeof(fname), "%s" SLASH "cache" SLASH "%s", confbase, node->name);
+ FILE *fp = fopen(fname, "rb");
+
+ if(!fp || fread(&cache->data, sizeof(cache->data), 1, fp) != 1 || cache->data.version != ADDRESS_CACHE_VERSION) {
+ memset(&cache->data, 0, sizeof(cache->data));
+ }
+
+ if(fp) {
+ fclose(fp);
+ }
+
+ // Ensure we have a valid state
+ cache->config_tree = NULL;
+ cache->cfg = NULL;
+ cache->ai = NULL;
+ cache->aip = NULL;
+ cache->tried = 0;
+ cache->data.version = ADDRESS_CACHE_VERSION;
+
+ if(cache->data.used > MAX_CACHED_ADDRESSES) {
+ cache->data.used = 0;
+ }
+
+ return cache;
+}
+
+void reset_address_cache(address_cache_t *cache, const sockaddr_t *sa) {
+ if(sa) {
+ add_recent_address(cache, sa);
+ }
+
+ if(cache->config_tree) {
+ exit_configuration(&cache->config_tree);
+ }
+
+ if(cache->ai) {
+ if(cache->tried == cache->data.used) {
+ free_known_addresses(cache->ai);
+ } else {
+ freeaddrinfo(cache->ai);
+ }
+ }
+
+ cache->config_tree = NULL;
+ cache->cfg = NULL;
+ cache->ai = NULL;
+ cache->aip = NULL;
+ cache->tried = 0;
+}
+
+void close_address_cache(address_cache_t *cache) {
+ if(cache->config_tree) {
+ exit_configuration(&cache->config_tree);
+ }
+
+ if(cache->ai) {
+ if(cache->tried == cache->data.used) {
+ free_known_addresses(cache->ai);
+ } else {
+ freeaddrinfo(cache->ai);
+ }
+ }
+
+ free(cache);
+}
projects / tinc / blobdiff