try to handle broken dns servers

git-svn: trunk@2249

clamav-devel/ChangeLog

@@ -1,3 +1,10 @@
+Wed Sep 13 17:46:06 CEST 2006 (tk)
+----------------------------------
+  * freshclam/dns.c: try to handle broken dns servers (such as in SpeedTouch
+		     510), the workaround must be enabled during installation
+		     Patch from Arnold Metselaar <arnold.metselaar*planet.nl>
+  * configure: new --enable-dns-fix switch
+
 Wed Sep 13 00:50:40 CEST 2006 (tk)
 ----------------------------------
   * shared/cfgparser.c: fix error path leaks, patch from Mark Pizzolato

clamav-devel/clamav-config.h.in

@@ -84,6 +84,9 @@
 /* file i/o buffer size */
 #undef FILEBUFF
 
+/* enable workaround for broken DNS servers */
+#undef FRESHCLAM_DNS_FIX
+
 /* use "Cache-Control: no-cache" in freshclam */
 #undef FRESHCLAM_NO_CACHE
 

clamav-devel/configure

@@ -1482,6 +1482,7 @@ Optional Features:
   --disable-clamav	  disable test for clamav user/group
   --enable-debug	  enable debug code
   --enable-no-cache	  use "Cache-Control: no-cache" in freshclam
+  --enable-dns-fix	  enable workaround for broken DNS servers (as in SpeedTouch 510)
   --enable-experimental	enable experimental code
   --enable-bigstack	  increase thread stack size
   --disable-gethostbyname_r	  disable support for gethostbyname_r
@@ -5882,7 +5883,7 @@ test "x$enable_libtool_lock" != xno && enable_libtool_lock=yes
 case $host in
 *-*-irix6*)
   # Find out which ABI we are using.
-  echo '#line 5885 "configure"' > conftest.$ac_ext
+  echo '#line 5886 "configure"' > conftest.$ac_ext
   if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
   (eval $ac_compile) 2>&5
   ac_status=$?
@@ -6515,7 +6516,7 @@ chmod -w .
 save_CFLAGS="$CFLAGS"
 CFLAGS="$CFLAGS -o out/conftest2.$ac_objext"
 compiler_c_o=no
-if { (eval echo configure:6518: \"$ac_compile\") 1>&5; (eval $ac_compile) 2>out/conftest.err; } && test -s out/conftest2.$ac_objext; then
+if { (eval echo configure:6519: \"$ac_compile\") 1>&5; (eval $ac_compile) 2>out/conftest.err; } && test -s out/conftest2.$ac_objext; then
   # The compiler can only warn and ignore the option if not recognized
   # So say no if there are warnings
   if test -s out/conftest.err; then
@@ -8551,7 +8552,7 @@ else
     lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<EOF
-#line 8554 "configure"
+#line 8555 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -8649,7 +8650,7 @@ else
     lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<EOF
-#line 8652 "configure"
+#line 8653 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -13174,6 +13175,22 @@ _ACEOF
 
 fi
 
+# Check whether --enable-dns-fix was given.
+if test "${enable_dns_fix+set}" = set; then
+  enableval=$enable_dns_fix; enable_dnsfix=$enableval
+else
+  enable_dnsfix="no"
+fi
+
+
+if test "$enable_dnsfix" = "yes"; then
+
+cat >>confdefs.h <<\_ACEOF
+#define FRESHCLAM_DNS_FIX 1
+_ACEOF
+
+fi
+
 # Check whether --enable-experimental was given.
 if test "${enable_experimental+set}" = set; then
   enableval=$enable_experimental; enable_experimental=$enableval

clamav-devel/configure.in

@@ -300,6 +300,14 @@ if test "$enable_nocache" = "yes"; then
   AC_DEFINE(FRESHCLAM_NO_CACHE,1,[use "Cache-Control: no-cache" in freshclam])
 fi
 
+AC_ARG_ENABLE(dns-fix,
+[  --enable-dns-fix	  enable workaround for broken DNS servers (as in SpeedTouch 510)],
+enable_dnsfix=$enableval, enable_dnsfix="no")
+
+if test "$enable_dnsfix" = "yes"; then
+  AC_DEFINE(FRESHCLAM_DNS_FIX,1,[enable workaround for broken DNS servers])
+fi
+
 AC_ARG_ENABLE(experimental,
 [  --enable-experimental	enable experimental code],
 enable_experimental=$enableval, enable_experimental="no")

clamav-devel/freshclam/dns.c

@@ -44,7 +44,7 @@
 char *txtquery(const char *domain, unsigned int *ttl)
 {
 	unsigned char answer[PACKETSZ], host[128], *pt, *txt;
-	int len, exp, cttl, size, txtlen, type;
+	int len, exp, cttl, size, txtlen, type, qtype;
 
 
     if(res_init() < 0) {
@@ -55,9 +55,24 @@ char *txtquery(const char *domain, unsigned int *ttl)
     logg("*Querying %s\n", domain);
 
     memset(answer, 0, PACKETSZ);
-    if((len = res_query(domain, C_IN, T_TXT, answer, PACKETSZ)) < 0) {
+    qtype = T_TXT;
+    if((len = res_query(domain, C_IN, qtype, answer, PACKETSZ)) < 0) {
+#ifdef FRESHCLAM_DNS_FIX
+	/*  The DNS server in the SpeedTouch Alcatel 510 modem can't
+	 *  handle a TXT-query, but it can resolve an ANY-query to a
+	 *  TXT-record, so we try an ANY-query now.  The thing we try
+	 *  to resolve normally only has a TXT-record anyway.  
+	 */
+	memset(answer, 0, PACKETSZ);
+	qtype=T_ANY;
+	if((len = res_query(domain, C_IN, qtype, answer, PACKETSZ)) < 0) {
+	    logg("^Can't query %s\n", domain);
+	    return NULL;
+	}
+#else
 	logg("^Can't query %s\n", domain);
 	return NULL;
+#endif
     }
 
     pt = answer + sizeof(HEADER);
@@ -70,7 +85,7 @@ char *txtquery(const char *domain, unsigned int *ttl)
     pt += exp;
 
     GETSHORT(type, pt);
-    if(type != T_TXT) {
+    if(type != qtype) {
 	logg("^Broken DNS reply.\n");
 	return NULL;
     }