Removed the DNS caching system because tinyproxy did not determine the TTL

of the host names being resolved, which is not recommended by RFC2616.
Basically, if a HTTP client doesn't respect the TTL is should not be
caching the address since it leaves itself open to DNS spoofing attacks.

Also, having a DNS caching system is an administater decision, and so
should not be included in the tinyproxy source.

1 files changed, 0 insertions, 147 deletions

diff --git a/src/dnscache.c b/src/dnscache.c
deleted file mode 100644
index a711c91..0000000
--- a/src/dnscache.c
+++ /dev/null
@@ -1,147 +0,0 @@
-/* $Id: dnscache.c,v 1.18 2001-11-22 00:31:10 rjkaes Exp $
- *
- * This is a caching DNS system. When a host name is needed we look it up here
- * and see if there is already an answer for it. The domains are placed in a
- * hashed linked list. If the name is not here, then we need to look it up and
- * add it to the system. This really speeds up the connection to servers since
- * the DNS name does not need to be looked up each time. It's kind of cool. :)
- *
- * Copyright (C) 1999  Robert James Kaes (rjkaes@flarenet.com)
- * Copyright (C) 2000  Chris Lightfoot (chris@ex-parrot.com)
- *
- * 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, 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.
- */
-
-#include "tinyproxy.h"
-
-#include "dnscache.h"
-#include "log.h"
-#include "ternary.h"
-#include "utils.h"
-
-/*
- * The mutex is used for locking around accesses to the ternary tree.
- */
-static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
-
-#define LOCK()   pthread_mutex_lock(&mutex);
-#define UNLOCK() pthread_mutex_unlock(&mutex);
-
-#define DNSEXPIRE (5 * 60)
-#define DNS_INSERT_LIMIT 10000	/* free the memory after inserts */
-
-struct dnscache_s {
-	struct in_addr ipaddr;
-	time_t expire;
-};
-
-static TERNARY dns_tree = -1;
-static unsigned int dns_insertions;
-
-static int
-dns_lookup(struct in_addr *addr, char *domain)
-{
-	int ret;
-	struct dnscache_s *ptr;
-
-	assert(addr != NULL);
-	assert(domain != NULL);
-
-	ret = ternary_search(dns_tree, domain, (void *) &ptr);
-
-	if (TE_ISERROR(ret)
-	    || difftime(time(NULL), ptr->expire) > DNSEXPIRE) {
-		return -1;
-	}
-
-	memcpy(addr, &ptr->ipaddr, sizeof(struct in_addr));
-
-	return 0;
-}
-
-static int
-dns_insert(struct in_addr *addr, char *domain)
-{
-	struct dnscache_s *newptr;
-
-	assert(addr != NULL);
-	assert(domain != NULL);
-
-	if (!(newptr = safemalloc(sizeof(struct dnscache_s)))) {
-		return -1;
-	}
-
-	memcpy(&newptr->ipaddr, addr, sizeof(struct in_addr));
-	newptr->expire = time(NULL);
-
-	DEBUG2("Inserting [%s] into DNS cache", domain);
-
-	if (TE_ISERROR(ternary_replace(dns_tree, domain, newptr))) {
-		safefree(newptr);
-		return -1;
-	}
-
-	DEBUG2("Finished inserting [%s] into DNS cache", domain);
-
-	return 0;
-}
-
-int
-dnscache(struct in_addr *addr, char *domain)
-{
-	struct hostent *resolv;
-
-	assert(addr != NULL);
-	assert(domain != NULL);
-
-	LOCK();
-
-	/* If the DNS tree doesn't exist, build a new one */
-	if (dns_tree < 0) {
-		dns_tree = ternary_new();
-		dns_insertions = 0;
-	}
-
-	if (inet_aton(domain, (struct in_addr *) addr) != 0) {
-		UNLOCK();
-		return 0;
-	}
-
-	/* Well, we're not dotted-decimal so we need to look it up */
-	if (dns_lookup(addr, domain) == 0) {
-		UNLOCK();
-		return 0;
-	}
-
-	/* Okay, so not in the list... need to actually look it up. */
-	if (!(resolv = gethostbyname(domain))) {
-		UNLOCK();
-		return -1;
-	}
-
-	memcpy(addr, resolv->h_addr_list[0], resolv->h_length);
-
-	dns_insert(addr, domain);
-
-	dns_insertions++;
-	if (dns_insertions > DNS_INSERT_LIMIT) {
-		log_message(LOG_INFO,
-			    "DNS Insertion limit reached (%u). Rebuilding cache.",
-			    dns_insertions);
-		ternary_destroy(dns_tree, free);
-		dns_tree = ternary_new();
-		dns_insertions = 0;
-	}
-
-	UNLOCK();
-
-	return 0;
-}