[reSIProcate] DnsUtils improvement

[Nils Ohlmeier <lists@xxxxxxxxxxxx>]

Hi there,

from ym own experiences with sipsak http://sipsak.org I would  conclude that 
the current implementation of DnsUtils::getLocalHostName will fail on many 
*nix systems. Unfortunately the result of gethostname() hardly depends on the 
configuration of the system.
The idea of the attached improvement is taken from the hostname binary 
(net-tools 1.60).

Secondly IMHO the function getLocalDomainName is also more or less broken, 
because on many systems getdomainname returns the NIS domain (which can be 
any given string) if it returns anything at all. Should I provide a similar 
fix for that, although it is currently not used anywhere?

At last a question: what is the reason that a DNS name is used in the 
Record-Route headers of repro instead of the IP address like in the Via?
Besides for high availability scenarios I can not find any good argument for 
inserting this extra DNS lookup step.

Regards
  Nils

Index: DnsUtil.cxx
===================================================================
--- DnsUtil.cxx	(revision 4501)
+++ DnsUtil.cxx	(working copy)
@@ -7,6 +7,7 @@
 #include <sys/ioctl.h>
 #include <net/if.h>
 #include <errno.h>
+#include <netdb.h>
 #endif
 
 #include <stdio.h>
@@ -44,6 +45,12 @@
          throw Exception("could not find local hostname",__FILE__,__LINE__);
       }
    }
+   struct hostent* he;
+   if ((he = gethostbyname(buffer)) != NULL) {
+     if (strchr(he->h_name, '.') != NULL) {
+       strncpy(buffer, he->h_name, 256);
+     }
+   }
    return Data(buffer);
 }