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/* |
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* Copyright (c) 2002-2003 Andy Smith |
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* Copyright (c) 2014-2016 ircd-hybrid development team |
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* |
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License as published by |
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* the Free Software Foundation; either version 2 of the License, or |
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* (at your option) any later version. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public License |
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* along with this program; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 |
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* USA |
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*/ |
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|
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/* |
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* A Negative caching implementation for IPv4/IPv6 addresses. The idea is that |
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* every time an IP address is seen, it is checked against a patricia trie. If |
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* the IP address was previously seen and within an acceptable period of time, |
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* it is not scanned again. Otherwise, the address is scanned as normal. If |
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* it is proven to be OK (i.e. it doesn't run an open proxy) then it is added |
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* to the trie. |
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*/ |
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|
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#include "setup.h" |
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|
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <sys/time.h> |
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#include <time.h> |
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#include <sys/types.h> |
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#include <sys/socket.h> |
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#include <netinet/in.h> |
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#include <arpa/inet.h> |
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|
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#include "irc.h" |
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#include "negcache.h" |
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#include "config.h" |
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#include "memory.h" |
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#include "log.h" |
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#include "patricia.h" |
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#include "list.h" |
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|
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|
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extern unsigned int OPT_DEBUG; |
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|
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static list_t *negcache_list; |
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static patricia_tree_t *negcache_trie; |
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|
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|
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/* |
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* Initialise the patricia trie we use for storing our negative cache. |
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*/ |
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void |
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negcache_init(void) |
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{ |
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if (negcache_trie) |
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/* Cache already exists */ |
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return; |
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|
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negcache_trie = New_Patricia(PATRICIA_MAXBITS); |
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negcache_list = list_create(); |
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} |
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|
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/* |
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* Check whether an IP address is in our negative cache and was added |
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* recently enough. Return a pointer to its node if so, NULL otherwise. |
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*/ |
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struct negcache_item * |
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check_neg_cache(const char *ipstr) |
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{ |
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if (OptionsItem->negcache == 0) |
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return NULL; |
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|
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patricia_node_t *pnode = try_search_exact(negcache_trie, (char *)ipstr); |
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if (pnode) |
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{ |
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struct negcache_item *n = pnode->data; |
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|
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if (time(NULL) - n->seen <= OptionsItem->negcache) |
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return n; |
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} |
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|
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return NULL; |
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} |
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|
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/* |
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* Prepare an ASCII string representing an IPv4/IPv6 address for inserting into |
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* our negative cache. |
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*/ |
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void |
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negcache_insert(const char *ipstr) |
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{ |
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patricia_node_t *pnode = make_and_lookup(negcache_trie, (char *)ipstr); |
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if (!pnode) |
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return; |
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|
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struct negcache_item *n = xcalloc(sizeof(*n)); |
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n->seen = time(NULL); |
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|
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pnode->data = n; |
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list_add(negcache_list, node_create(pnode)); |
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} |
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|
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/* |
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* Wrapper for recursive rebuild function. |
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*/ |
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void |
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negcache_rebuild(void) |
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{ |
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node_t *node, *node_next; |
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|
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LIST_FOREACH_SAFE(node, node_next, negcache_list->head) |
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{ |
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patricia_node_t *pnode = node->data; |
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struct negcache_item *n = pnode->data; |
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|
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if (n->seen + OptionsItem->negcache < time(NULL)) |
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{ |
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if (OPT_DEBUG >= 2) |
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log_printf("NEGCACHE -> Deleting expired negcache node for %s added at %lu", |
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prefix_toa(pnode->prefix), n->seen); |
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|
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list_remove(negcache_list, node); |
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node_free(node); |
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xfree(n); |
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patricia_remove(negcache_trie, pnode); |
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} |
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} |
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} |