changes/bug12377

@@ -0,0 +1,5 @@
+  o Minor bugfixes:
+    - On Linux systems try to use an AF_NETLINK socket to determine the
+      external interface's IP address, before falling back to the various
+      older approaches (interface enumeration and then a UDP socket based
+      hack). Fixes part of #12377. Bugfix on Tor 0.2.3.11-alpha.

configure.ac

@@ -930,6 +930,8 @@ AC_CHECK_HEADERS(
         inttypes.h \
         limits.h \
         linux/types.h \
+        linux/netlink.h \
+        linux/rtnetlink.h \
         machine/limits.h \
         malloc.h \
         malloc/malloc.h \

src/common/address.c

@@ -24,6 +24,7 @@
 #include "compat.h"
 #include "util.h"
 #include "address.h"
+#include "netlink.h"
 #include "torlog.h"
 #include "container.h"
 #include "sandbox.h"
@@ -1589,6 +1590,10 @@ get_interface_address6,(int severity, sa_family_t family, tor_addr_t *addr))
   smartlist_t *addrs;
   tor_assert(addr);
 
+  /* Try to do this the routing table aware smart way if possible. */
+  if (!get_interface_address_netlink(severity, family, addr))
+    return 0;
+
   /* Try to do this the smart way if possible. */
   if ((addrs = get_interface_addresses_raw(severity))) {
     int rv = -1;

src/common/include.am

@@ -60,6 +60,7 @@ LIBOR_A_SOURCES = \
   src/common/di_ops.c					\
   src/common/log.c					\
   src/common/memarea.c					\
+  src/common/netlink.c					\
   src/common/util.c					\
   src/common/util_process.c				\
   src/common/sandbox.c					\
@@ -118,6 +119,7 @@ COMMONHEADERS = \
   src/common/crypto_s2k.h			\
   src/common/di_ops.h				\
   src/common/memarea.h				\
+  src/common/netlink.h				\
   src/common/linux_syscalls.inc			\
   src/common/procmon.h				\
   src/common/sandbox.h				\