X-Git-Url: http://pileus.org/git/?a=blobdiff_plain;f=checkalias.c;h=6437db4c7c7f979b535e564bc9e5859fb7a583b2;hb=33cddbff323efcbae1503e91e6e65b2733da80c7;hp=1eca63daadc7c19409d3fc83ffd555fbc9d30911;hpb=b75b43db636a92444be6224e56c765edece19fc3;p=~andy%2Ffetchmail

diff --git a/checkalias.c b/checkalias.c
index 1eca63da..6437db4c 100644
--- a/checkalias.c
+++ b/checkalias.c
@@ -1,82 +1,75 @@
 /*
- * checkalias.c -- check to see if the IP addresses of two hosts are the same
+ * checkalias.c -- check to see if two hostnames or IP addresses are equivalent
  *
  * Copyright 1997 by Eric S. Raymond
  * For license terms, see the file COPYING in this directory.
  */
-
+#include "config.h"
+#include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
 #include <sys/types.h>
-#include <sys/socket.h>
-#include <netinet/in.h>
-#include <arpa/inet.h>
-#include <netdb.h>
-#include "fetchmail.h"
- 
-int is_ip_alias(const char *name1,const char *name2)
-/* Given two hostnames as arguments, returns TRUE if they
- * have at least one IP address in common.
- * It is meant to be called by the is_host_alias() function in driver.c
- * No check is done on errors returned by gethostbyname,
- * the calling function does them.
- */
-{
-    typedef unsigned char address_t[sizeof (struct in_addr)]; 
-    typedef struct _address_e
-    {
-	struct _address_e *next;
-	address_t address;
-    } 
-    address_e;
-    address_e *host_a_addr, *host_b_addr,*dummy_addr;
-
-    int i;
-    struct hostent *hp;
-    char **p;
- 
-    hp = gethostbyname(name1);
- 
-    dummy_addr = (address_e *)NULL;
-
-    for (i=0,p = hp->h_addr_list; *p != 0; i++,p++)
-    {
-	struct in_addr in;
-	(void) memcpy(&in.s_addr, *p, sizeof (in.s_addr));
-	host_a_addr = (address_e *)xmalloc(sizeof( address_e));
-	memset (host_a_addr,0, sizeof (address_e));
-	host_a_addr->next = dummy_addr;
-	(void) memcpy(&host_a_addr->address, *p, sizeof (in.s_addr));
-	dummy_addr = host_a_addr;
-    }
 
+#include "fetchmail.h"
 
-    hp = gethostbyname(name2);
+int is_host_alias(const char *name, struct query *ctl, struct addrinfo **res)
+/* determine whether name is a DNS alias of the mailserver for this query */
+{
+    struct idlist	*idl;
+    size_t		namelen;
 
-    dummy_addr = (address_e *)NULL;
+    struct hostdata *lead_server =
+	ctl->server.lead_server ? ctl->server.lead_server : &ctl->server;
 
-    for (i=0,p = hp->h_addr_list; *p != 0; i++,p++)
-    {
-	struct in_addr in;
-	(void) memcpy(&in.s_addr, *p, sizeof (in.s_addr));
-	host_b_addr = (address_e *)xmalloc(sizeof( address_e));
-	memset (host_b_addr,0, sizeof (address_e));
-	host_b_addr->next = dummy_addr;
-	(void) memcpy(&host_b_addr->address, *p, sizeof (in.s_addr));
-	dummy_addr = host_b_addr;
-    }
+    /*
+     * The first two checks are optimizations that will catch a good
+     * many cases.
+     *
+     * (1) check against the `true name' deduced from the poll label
+     * and the via option (if present) at the beginning of the poll cycle.
+     * Odds are good this will either be the mailserver's FQDN or a suffix of
+     * it with the mailserver's domain's default host name omitted.
+     *
+     * (2) Then check the rest of the `also known as'
+     * cache accumulated by previous DNS checks.  This cache is primed
+     * by the aka list option.
+     *
+     * Any of these on a mail address is definitive.  Only if the
+     * name doesn't match any is it time to call the bind library.
+     * If this happens odds are good we're looking at an MX name.
+     */
+    if (strcasecmp(lead_server->truename, name) == 0)
+	return(TRUE);
+    else if (str_in_list(&lead_server->akalist, name, TRUE))
+	return(TRUE);
 
-    while (host_a_addr)
+    /*
+     * Now check for a suffix match on the akalist.  The theory here is
+     * that if the user says `aka netaxs.com', we actually want to match
+     * foo.netaxs.com and bar.netaxs.com.
+     */
+    namelen = strlen(name);
+    for (idl = lead_server->akalist; idl; idl = idl->next)
     {
-	while (host_b_addr)
-	{
-	    if (!memcmp(host_b_addr->address,host_a_addr->address, sizeof (address_t)))
-		return (TRUE);
+	const char	*ep;
 
-	    host_b_addr = host_b_addr->next;
-	}
-	host_a_addr = host_a_addr->next;
+	/*
+	 * Test is >= here because str_in_list() should have caught the
+	 * equal-length case above.  Doing it this way guarantees that
+	 * ep[-1] is a valid reference.
+	 */
+	if (strlen(idl->id) >= namelen)
+	    continue;
+	ep = name + (namelen - strlen(idl->id));
+	/* a suffix led by . must match */
+	if (ep[-1] == '.' && !strcasecmp(ep, idl->id))
+	    return(TRUE);
     }
-    return (FALSE);
+
+    if (!ctl->server.dns)
+	return(FALSE);
+    (void)res;
+    return(FALSE);
 }
 
+/* checkalias.c ends here */