ipops: new cfg function dns_nc_match_ip(hostname, ipaddr)

- do dns query for the hostname and compare the result to see if is a
  match with ipaddr

modules/ipops/README

@@ -36,6 +36,7 @@ I
               4.8. compare_pure_ips (ip1, ip2)
               4.9. is_ip_rfc1918 (ip)
               4.10. is_in_subnet (ip, subnet)
+              4.11. dns_nc_match_ip(hostname, ipaddr)
 
    List of Examples
 
@@ -49,6 +50,7 @@ I
    1.8. compare_pure_ips usage
    1.9. is_ip_rfc1918 usage
    1.10. is_in_subnet usage
+   1.11. dns_nc_match_ip usage
 
 Chapter 1. Admin Guide
 
@@ -73,6 +75,7 @@ Chapter 1. Admin Guide
         4.8. compare_pure_ips (ip1, ip2)
         4.9. is_ip_rfc1918 (ip)
         4.10. is_in_subnet (ip, subnet)
+        4.11. dns_nc_match_ip(hostname, ipaddr)
 
 1. Overview
 
@@ -124,6 +127,7 @@ Chapter 1. Admin Guide
    4.8. compare_pure_ips (ip1, ip2)
    4.9. is_ip_rfc1918 (ip)
    4.10. is_in_subnet (ip, subnet)
+   4.11. dns_nc_match_ip(hostname, ipaddr)
 
 4.1. is_ip (ip)
 
@@ -329,3 +333,23 @@ if (is_in_subnet("10.0.123.123", "10.0.123.1/24")) {
   xlog("L_INFO", "it's in the subnet\n");
 }
 ...
+
+4.11. dns_nc_match_ip(hostname, ipaddr)
+
+   Returns TRUE if ipaddr is associated by DNS to hostname. FALSE
+   otherwise. It does not use the internal DNS cache, but directly
+   getaddrinfo(...).
+
+   Parameters:
+     * ipaddr - string or pseudo-variable containing the ip address.
+     * hostname - string or pseudo-variable containing the hostname. The
+       resulting IP addresses from DNS query are compared with ipaddress.
+
+   This function can be used from ANY_ROUTE.
+
+   Example 1.11. dns_nc_match_ip usage
+...
+if (!dns_nc_match_ip("myhost.com", "1.2.3.4")) {
+    xdbg("ip address not associated with hostname\n");
+}
+...

modules/ipops/doc/ipops_admin.xml

@@ -523,6 +523,51 @@ if (is_ip_rfc1918("10.0.123.123")) {
 if (is_in_subnet("10.0.123.123", "10.0.123.1/24")) {
   xlog("L_INFO", "it's in the subnet\n");
 }
+...
+        </programlisting>
+      </example>
+
+    </section>
+
+    <section id="ipops.f.dns_nc_match_ip">
+      <title>
+        <function moreinfo="none">dns_nc_match_ip(hostname, ipaddr)</function>
+      </title>
+
+      <para>
+		  Returns TRUE if ipaddr is associated by DNS to hostname. FALSE otherwise. It
+		  does not use the internal DNS cache, but directly getaddrinfo(...).
+      </para>
+
+      <para>Parameters:</para>
+
+      <itemizedlist>
+        <listitem>
+          <para>
+            <emphasis>ipaddr</emphasis> - string or pseudo-variable containing the ip address.
+          </para>
+        </listitem>
+        <listitem>
+          <para>
+			  <emphasis>hostname</emphasis> - string or pseudo-variable containing the hostname.
+			  The resulting IP addresses from DNS query are compared with ipaddress.
+          </para>
+        </listitem>
+      </itemizedlist>
+
+      <para>
+        This function can be used from ANY_ROUTE.
+      </para>
+
+      <example>
+        <title>
+          <function>dns_nc_match_ip</function> usage
+        </title>
+        <programlisting format="linespecific">
+...
+if (!dns_nc_match_ip("myhost.com", "1.2.3.4")) {
+    xdbg("ip address not associated with hostname\n");
+}
 ...
         </programlisting>
       </example>

modules/ipops/ipops_mod.c

@@ -40,12 +40,16 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netdb.h>
 #include <arpa/inet.h>
 #include "../../sr_module.h"
 #include "../../dprint.h"
 #include "../../str.h"
 #include "../../mod_fix.h"
 #include "../../pvar.h"
+#include "../../resolve.h"
 #include "api.h"
 #include "ip_parser.h"
 #include "rfc1918_parser.h"
@@ -83,6 +87,7 @@ static int w_compare_ips(struct sip_msg*, char*, char*);
 static int w_compare_pure_ips(struct sip_msg*, char*, char*);
 static int w_is_ip_rfc1918(struct sip_msg*, char*);
 static int w_ip_is_in_subnet(struct sip_msg*, char*, char*);
+static int w_dns_nc_match_ip(sip_msg_t*, char*, char*);
 
 
 /*
@@ -110,6 +115,8 @@ static cmd_export_t cmds[] =
   REQUEST_ROUTE|FAILURE_ROUTE|ONREPLY_ROUTE|BRANCH_ROUTE|LOCAL_ROUTE },
   { "is_in_subnet", (cmd_function)w_ip_is_in_subnet, 2, fixup_spve_spve, 0,
   REQUEST_ROUTE|FAILURE_ROUTE|ONREPLY_ROUTE|BRANCH_ROUTE|LOCAL_ROUTE },
+  { "dns_nc_match_ip", (cmd_function)w_dns_nc_match_ip, 2, fixup_spve_spve, 0,
+  ANY_ROUTE },
   { "bind_ipops", (cmd_function)bind_ipops, 0, 0, 0, 0},
   { 0, 0, 0, 0, 0, 0 }
 };
@@ -596,3 +603,80 @@ static int w_is_ip_rfc1918(struct sip_msg* _msg, char* _s)
   else
     return -1;
 }
+
+static inline ip_addr_t *strtoipX(str *ips)
+{
+	/* try to figure out INET class */
+	if(ips->s[0] == '[' || memchr(ips->s, ':', ips->len)!=NULL)
+	{
+		/* IPv6 */
+		return str2ip6(ips);
+	} else {
+		/* IPv4 */
+		return str2ip(ips);
+	}
+}
+
+static int w_dns_nc_match_ip(sip_msg_t *msg, char *hnp, char *ipp)
+{
+	struct addrinfo hints, *res, *p;
+	int status;
+	ip_addr_t *ipa;
+	void *addr;
+	str hns;
+	str ips;
+	struct sockaddr_in *ipv4;
+	struct sockaddr_in6 *ipv6;
+
+	if (fixup_get_svalue(msg, (gparam_p)hnp, &hns))
+	{
+		LM_ERR("cannot evaluate hostname parameter\n");
+		return -2;
+	}
+
+	if (fixup_get_svalue(msg, (gparam_p)ipp, &ips))
+	{
+		LM_ERR("cannot evaluate ip address parameter\n");
+		return -2;
+	}
+
+	ipa = strtoipX(&ips);
+	if(ipa==NULL)
+	{
+		LM_ERR("invalid ip address: %.*s\n", ips.len, ips.s);
+		return -3;
+	}
+
+	memset(&hints, 0, sizeof(hints));
+	hints.ai_family = AF_UNSPEC; /* allow any of AF_INET or AF_INET6 */
+
+	if ((status = getaddrinfo(hns.s, NULL, &hints, &res)) != 0)
+	{
+        LM_ERR("getaddrinfo: %s\n", gai_strerror(status));
+        return -2;
+    }
+
+	for(p = res;p != NULL; p = p->ai_next)
+	{
+		if(p->ai_family==ipa->af)
+		{
+			if (p->ai_family==AF_INET)
+			{
+				ipv4 = (struct sockaddr_in *)p->ai_addr;
+				addr = &(ipv4->sin_addr);
+			} else {
+				ipv6 = (struct sockaddr_in6 *)p->ai_addr;
+				addr = &(ipv6->sin6_addr);
+			}
+			if(memcmp(ipa->u.addr, addr, ipa->len)==0)
+			{
+				/* matched IP */
+				freeaddrinfo(res);
+				return 1;
+			}
+		}
+    }
+	freeaddrinfo(res);
+
+	return -1;
+}