[GNUnet-SVN] r38085 - gnunet/src/dns

[gnunet]

Author: grothoff
Date: 2016-10-09 14:00:15 +0200 (Sun, 09 Oct 2016)
New Revision: 38085

Modified:
   gnunet/src/dns/gnunet-helper-dns.c
Log:
do not try to intercept link local DNS traffic, as we cannot properly re-inject 
it intot the kernel's IP stack

Modified: gnunet/src/dns/gnunet-helper-dns.c
===================================================================
--- gnunet/src/dns/gnunet-helper-dns.c  2016-10-09 11:51:12 UTC (rev 38084)
+++ gnunet/src/dns/gnunet-helper-dns.c  2016-10-09 12:00:15 UTC (rev 38085)
@@ -966,14 +966,16 @@
         "ACCEPT", NULL
         };
       if (0 != fork_and_exec (sbin_ip6tables, mangle_args))
-        goto cleanup_rest;
+        goto cleanup_mangle_1b;
     }
-    /* Mark all of the other DNS traffic using our mark DNS_MARK */
+    /* Mark all of the other DNS traffic using our mark DNS_MARK,
+       unless it is on a link-local IPv6 address, which we cannot support. */
     {
       char *const mark_args[] =
         {
         "iptables", "-t", "mangle", "-I", "OUTPUT", "2", "-p",
-        "udp", "--dport", DNS_PORT, "-j", "MARK", "--set-mark", DNS_MARK,
+        "udp", "--dport", DNS_PORT,
+         "-j", "MARK", "--set-mark", DNS_MARK,
         NULL
         };
       if (0 != fork_and_exec (sbin_iptables, mark_args))
@@ -983,11 +985,13 @@
       char *const mark_args[] =
         {
         "ip6tables", "-t", "mangle", "-I", "OUTPUT", "2", "-p",
-        "udp", "--dport", DNS_PORT, "-j", "MARK", "--set-mark", DNS_MARK,
+        "udp", "--dport", DNS_PORT,
+         "!", "-s", "fe80::/10", /* this line excludes link-local traffic */
+         "-j", "MARK", "--set-mark", DNS_MARK,
         NULL
         };
       if (0 != fork_and_exec (sbin_ip6tables, mark_args))
-        goto cleanup_mangle_1;
+        goto cleanup_mark_2b;
     }
     /* Forward all marked DNS traffic to our DNS_TABLE */
     {
@@ -1004,7 +1008,7 @@
           "ip", "-6", "rule", "add", "fwmark", DNS_MARK, "table", DNS_TABLE, 
NULL
         };
       if (0 != fork_and_exec (sbin_ip, forward_args))
-        goto cleanup_mark_2;
+        goto cleanup_forward_3b;
     }
     /* Finally, add rule in our forwarding table to pass to our virtual 
interface */
     {
@@ -1023,7 +1027,7 @@
           "table", DNS_TABLE, NULL
         };
       if (0 != fork_and_exec (sbin_ip, route_args))
-        goto cleanup_forward_3;
+        goto cleanup_route_4b;
     }
   }
 
@@ -1049,7 +1053,7 @@
   r = 0; /* did fully setup routing table (if nothing else happens, we were 
successful!) */
 
   /* now forward until we hit a problem */
-   run (fd_tun);
+  run (fd_tun);
 
   /* now need to regain privs so we can remove the firewall rules we added! */
 #ifdef HAVE_SETRESUID
@@ -1075,17 +1079,18 @@
   {
     char *const route_clean_args[] =
       {
-       "ip", "route", "del", "default", "dev", dev,
+       "ip", "-6", "route", "del", "default", "dev", dev,
        "table", DNS_TABLE, NULL
       };
     if (0 != fork_and_exec (sbin_ip, route_clean_args))
       r += 1;
   }
+ cleanup_route_4b:
   if (0 == nortsetup)
   {
     char *const route_clean_args[] =
       {
-       "ip", "-6", "route", "del", "default", "dev", dev,
+       "ip", "route", "del", "default", "dev", dev,
        "table", DNS_TABLE, NULL
       };
     if (0 != fork_and_exec (sbin_ip, route_clean_args))
@@ -1096,16 +1101,17 @@
   {
     char *const forward_clean_args[] =
       {
-       "ip", "rule", "del", "fwmark", DNS_MARK, "table", DNS_TABLE, NULL
+       "ip", "-6", "rule", "del", "fwmark", DNS_MARK, "table", DNS_TABLE, NULL
       };
     if (0 != fork_and_exec (sbin_ip, forward_clean_args))
       r += 2;
   }
+ cleanup_forward_3b:
   if (0 == nortsetup)
   {
     char *const forward_clean_args[] =
       {
-       "ip", "-6", "rule", "del", "fwmark", DNS_MARK, "table", DNS_TABLE, NULL
+       "ip", "rule", "del", "fwmark", DNS_MARK, "table", DNS_TABLE, NULL
       };
     if (0 != fork_and_exec (sbin_ip, forward_clean_args))
       r += 2;
@@ -1115,20 +1121,23 @@
   {
     char *const mark_clean_args[] =
       {
-       "iptables", "-t", "mangle", "-D", "OUTPUT", "-p", "udp",
-       "--dport", DNS_PORT, "-j", "MARK", "--set-mark", DNS_MARK, NULL
+       "ip6tables", "-t", "mangle", "-D", "OUTPUT", "-p", "udp",
+       "--dport", DNS_PORT,
+        "!", "-s", "fe80::/10", /* this line excludes link-local traffic */
+        "-j", "MARK", "--set-mark", DNS_MARK, NULL
       };
-    if (0 != fork_and_exec (sbin_iptables, mark_clean_args))
+    if (0 != fork_and_exec (sbin_ip6tables, mark_clean_args))
       r += 4;
   }
+ cleanup_mark_2b:
   if (0 == nortsetup)
   {
     char *const mark_clean_args[] =
       {
-       "ip6tables", "-t", "mangle", "-D", "OUTPUT", "-p", "udp",
+       "iptables", "-t", "mangle", "-D", "OUTPUT", "-p", "udp",
        "--dport", DNS_PORT, "-j", "MARK", "--set-mark", DNS_MARK, NULL
       };
-    if (0 != fork_and_exec (sbin_ip6tables, mark_clean_args))
+    if (0 != fork_and_exec (sbin_iptables, mark_clean_args))
       r += 4;
   }
  cleanup_mangle_1:
@@ -1136,22 +1145,23 @@
   {
     char *const mangle_clean_args[] =
       {
-       "iptables", "-m", "owner", "-t", "mangle", "-D", "OUTPUT", "-p", "udp",
+       "ip6tables", "-m", "owner", "-t", "mangle", "-D", "OUTPUT", "-p", "udp",
         "--gid-owner", mygid, "--dport", DNS_PORT, "-j", "ACCEPT",
        NULL
       };
-    if (0 != fork_and_exec (sbin_iptables, mangle_clean_args))
+    if (0 != fork_and_exec (sbin_ip6tables, mangle_clean_args))
       r += 8;
   }
+ cleanup_mangle_1b:
   if (0 == nortsetup)
   {
     char *const mangle_clean_args[] =
       {
-       "ip6tables", "-m", "owner", "-t", "mangle", "-D", "OUTPUT", "-p", "udp",
+       "iptables", "-m", "owner", "-t", "mangle", "-D", "OUTPUT", "-p", "udp",
         "--gid-owner", mygid, "--dport", DNS_PORT, "-j", "ACCEPT",
        NULL
       };
-    if (0 != fork_and_exec (sbin_ip6tables, mangle_clean_args))
+    if (0 != fork_and_exec (sbin_iptables, mangle_clean_args))
       r += 8;
   }