[pisa-src] r1745 - trunk/pisacd/cdservers.c

From: Thomas Jansen <mithi@xxxxxxxxx>
To: pisa-src@xxxxxxxxxxxxx
Date: Mon, 23 Nov 2009 16:46:29 +0100
Author: tjansen
Date: Mon Nov 23 16:46:26 2009
New Revision: 1745

Log:
Added DNS backend.

Look up HIT and remote IPv4 via DNS. Still needs proper error handling.

Modified:
   trunk/pisacd/cdservers.c

Modified: trunk/pisacd/cdservers.c
==============================================================================
--- trunk/pisacd/cdservers.c    Mon Nov 23 15:07:19 2009        (r1744)
+++ trunk/pisacd/cdservers.c    Mon Nov 23 16:46:26 2009        (r1745)
@@ -10,6 +10,12 @@
  * @date Jun. 2009
  */
 
+#define _XOPEN_SOURCE
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netdb.h>
+
 #include "cdconf.h"
 #include "cdctx.h"
 #include "cdregister.h"
@@ -220,42 +226,73 @@
 }
 
 /**
+ * Get the HIT and remote IPv4 of a service specified by a virtual local IP
+ * address.
+ *
+ * @param dn domain name
+ * @param hit destination buffer for the HIT
+ * @param remote destination buffer for the remote IPv4
+ * @return true on success, false otherwise
+ */
+static bool pisa_servers_lookup_dns(char *dn, struct in6_addr *hit, struct 
in_addr *remote)
+{
+       bool found_hit = false, found_remote = false;
+       struct addrinfo *ai, *ais = NULL, hints;
+
+       memset(&hints, 0, sizeof(hints));
+       hints.ai_family = AF_UNSPEC;
+       hints.ai_socktype = SOCK_DGRAM;
+       hints.ai_flags = AI_PASSIVE;
+
+       if (getaddrinfo(dn, NULL, &hints, &ais) != 0)
+               return false;
+
+       for (ai = ais; ai; ai = ai->ai_next) {
+               if (ai->ai_family == AF_INET) {
+                       struct sockaddr_in *tmp = (struct sockaddr_in *) 
ai->ai_addr;
+                       pisa_ipv4_copy(remote, &tmp->sin_addr);
+                       found_remote = true;
+               } else if (ai->ai_family == AF_INET6) {
+                       struct sockaddr_in6 *tmp = (struct sockaddr_in6 *) 
ai->ai_addr;
+                       pisa_ipv6_copy(hit, &tmp->sin6_addr);
+                       found_hit = true;
+               }
+       }
+
+       if (ais)
+               freeaddrinfo(ais);
+
+       return found_hit && found_remote;
+}
+
+/**
  * Retrieve the NAT mapping and the conmgr entry from DNS.
  *
  * TODO: Remove the NAT mapping if an error occurs. Otherwise we might have a
  * DOS attack vector: Attacker sends a lot of packets to different
  * (non-existant) virtual addresses the allocate memory for a NAT mapping.
  *
- * This is currently a stub using hardcoded values for Thomas' virtual
- * machines.
- *
  * @param data NAT mapping
  */
 static void pisa_servers_query_dns(void *data)
 {
        pisa_nat_mapping *nat = (pisa_nat_mapping *) data;
-       char local_str[INET_ADDRSTRLEN], remote_str[INET_ADDRSTRLEN];
-       char hit_str[INET6_ADDRSTRLEN], dn[128];
+       char dn[128];
        pisa_conmgr_entry *entry;
        struct in6_addr hit;
        struct in_addr remote;
 
-       inet_pton(AF_INET6, "2001:16:415e:da37:11f6:d0e7:33f5:3ee7", &hit);
-       inet_pton(AF_INET, "192.168.151.31", &remote);
-
-       entry = pisa_conmgr_findby_hit(cd_ctx.conlist, &hit);
+       if (!pisa_servers_build_domain_name(&nat->local_private, dn, 
sizeof(dn)))
+               return;
+       if (!pisa_servers_lookup_dns(dn, &hit, &remote))
+               return;
 
+       /* TODO: If no conmgr entry exists we have to build one... */
+       if (!(entry = pisa_conmgr_findby_hit(cd_ctx.conlist, &hit)))
+               return;
        pisa_nat_upgrade_preliminary(cd_ctx.natlist, nat, &remote, entry, NULL);
 
-       pisa_servers_build_domain_name(&nat->local_private, dn, sizeof(dn));
-       PISA_DEBUG(PL_CONFIG, "domain name: %s\n", dn);
-
-       inet_ntop(AF_INET, &nat->local_private, local_str, sizeof(local_str));
-       inet_ntop(AF_INET, &nat->remote.ipv4, remote_str, sizeof(remote_str));
-       inet_ntop(AF_INET6, &nat->remote.hit, hit_str, sizeof(hit_str));
-
-       PISA_DEBUG(PL_CONFIG, "Upgraded NAT mapping: local: %s remote %s HIT 
%s\n",
-       local_str, remote_str, hit_str);
+       /* TODO: clean up after failure, otherwise we're stuck */
 }
 
 /**
[pisa-src] r1745 - trunk/pisacd/cdservers.c

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