* Removed all of the thread cancellation cruft that is no longer necessary

[citadel.git] / citadel / locate_host.c

diff --git a/citadel/locate_host.c b/citadel/locate_host.c
index 9160c2d9a62b5e2f35d3ea9134ce9b23f047535a..b4f5cdbadcbb810385a4908cc26f82219f4b1a51 100644 (file)
--- a/citadel/locate_host.c
+++ b/citadel/locate_host.c
@@ -14,39 +14,56 @@
 #include <limits.h>
 #include <netdb.h>
 #include <string.h>
-#ifdef HAVE_PTHREAD_H
-#include <pthread.h>
-#endif
 #include "citadel.h"
 #include "server.h"
 #include "locate_host.h"
 #include "config.h"
+#include "tools.h"
 
-void locate_host(char *tbuf)
+void locate_host(char *tbuf, const struct in_addr *addr)
 {
-       struct sockaddr_in      cs;     
-       struct hostent      *   ch;        
-       int                     len;     
+       struct hostent *ch;
        char *i;
-       int a1,a2,a3,a4;
-       
-    len = sizeof(cs);   
-    if (getpeername(CC->client_socket, (struct sockaddr *)&cs,&len) < 0){   
-       strcpy(tbuf,config.c_fqdn);
-       return;
+       int a1, a2, a3, a4;
+
+#ifdef HAVE_NONREENTRANT_NETDB
+       begin_critical_section(S_NETDB);
+#endif
+
+       if ((ch = gethostbyaddr((char *) addr, sizeof(*addr), AF_INET)) ==
+           NULL) {
+             bad_dns:
+               i = (char *) addr;
+               a1 = ((*i++) & 0xff);
+               a2 = ((*i++) & 0xff);
+               a3 = ((*i++) & 0xff);
+               a4 = ((*i++) & 0xff);
+               sprintf(tbuf, "%d.%d.%d.%d", a1, a2, a3, a4);
+               goto end;       /* because we might need to end the critical
+                                  section */
        }
-     
-    if((ch = gethostbyaddr((char *) &cs.sin_addr, sizeof(cs.sin_addr),  
-         AF_INET)) == NULL) { 
-               i = (char *) &cs.sin_addr;
-               a1 = ((*i++)&0xff);
-               a2 = ((*i++)&0xff);
-               a3 = ((*i++)&0xff);
-               a4 = ((*i++)&0xff);
-               sprintf(tbuf,"%d.%d.%d.%d",a1,a2,a3,a4);
-               return;
+       /* check if the forward DNS agrees; if not, they're spoofing */
+       i = strdoop(ch->h_name);
+       ch = gethostbyname(i);
+       phree(i);
+       if (ch == NULL)
+               goto bad_dns;
+
+       /* check address for consistency */
+       for (; *ch->h_addr_list; ch->h_addr_list++)
+               if (!memcmp(*ch->h_addr_list, addr,
+                           sizeof *addr)) {
+                       safestrncpy(tbuf, ch->h_name, 25);
+                       goto end;
                }
+       goto bad_dns;           /* they were spoofing. report a numeric IP
+                                  address. */
 
-       strncpy(tbuf,ch->h_name, 24);
-       tbuf[24] = 0;
-       }
+      end:
+
+#ifdef HAVE_NONREENTRANT_NETDB
+       end_critical_section(S_NETDB);
+#endif
+
+       tbuf[25] = 0;
+}