retain subdomain of hostname if any

[l2tpns.git] / l2tpns.c

diff --git a/l2tpns.c b/l2tpns.c
index d95517e..a265507 100644 (file)
--- a/l2tpns.c
+++ b/l2tpns.c
@@ -4,7 +4,7 @@
 // Copyright (c) 2002 FireBrick (Andrews & Arnold Ltd / Watchfront Ltd) - GPL licenced
 // vim: sw=8 ts=8
 
-char const *cvs_id_l2tpns = "$Id: l2tpns.c,v 1.39 2004-11-03 13:23:58 bodea Exp $";
+char const *cvs_id_l2tpns = "$Id: l2tpns.c,v 1.40 2004-11-04 05:08:36 bodea Exp $";
 
 #include <arpa/inet.h>
 #include <assert.h>
@@ -23,6 +23,7 @@ char const *cvs_id_l2tpns = "$Id: l2tpns.c,v 1.39 2004-11-03 13:23:58 bodea Exp
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
+#include <ctype.h>
 #include <sys/ioctl.h>
 #include <sys/socket.h>
 #include <sys/stat.h>
@@ -2442,6 +2443,71 @@ void mainloop(void)
        // Important!!! We MUST not process any packets past this point!
 }
 
+static void stripdomain(char *host)
+{
+       char *p;
+
+       if ((p = strchr(host, '.')))
+       {
+               char *domain = 0;
+               char _domain[1024];
+
+               // strip off domain
+               FILE *resolv = fopen("/etc/resolv.conf", "r");
+               if (resolv)
+               {
+                       char buf[1024];
+                       char *b;
+
+                       while (fgets(buf, sizeof(buf), resolv))
+                       {
+                               if (strncmp(buf, "domain", 6) && strncmp(buf, "search", 6))
+                                       continue;
+
+                               if (!isspace(buf[6]))
+                                       continue;
+
+                               b = buf + 7;
+                               while (isspace(*b)) b++;
+
+                               if (*b)
+                               {
+                                       char *d = b;
+                                       while (*b && !isspace(*b)) b++;
+                                       *b = 0;
+                                       if (buf[0] == 'd') // domain is canonical
+                                       {
+                                               domain = d;
+                                               break;
+                                       }
+
+                                       // first search line
+                                       if (!domain)
+                                       {
+                                               // hold, may be subsequent domain line
+                                               strncpy(_domain, d, sizeof(_domain))[sizeof(_domain)-1] = 0;
+                                               domain = _domain;
+                                       }
+                               }
+                       }
+
+                       fclose(resolv);
+               }
+
+               if (domain)
+               {
+                       int hl = strlen(host);
+                       int dl = strlen(domain);
+                       if (dl < hl && host[hl - dl - 1] == '.' && !strcmp(host + hl - dl, domain))
+                               host[hl -dl - 1] = 0;
+               }
+               else
+               {
+                       *p = 0; // everything after first dot
+               }
+       }
+}
+
 // Init data structures
 void initdata(int optdebug, char *optconfig)
 {
@@ -2536,10 +2602,9 @@ void initdata(int optdebug, char *optconfig)
 
        if (!*hostname)
        {
-               char *p;
                // Grab my hostname unless it's been specified
                gethostname(hostname, sizeof(hostname));
-               if ((p = strchr(hostname, '.'))) *p = 0;
+               stripdomain(hostname);
        }
 
        _statistics->start_time = _statistics->last_reset = time(NULL);