[tor-dev] [PATCH 1/2] New option LocalOutboundBindAddress

[Andrew Cady]

This works just like OutboundBindAddress, but instead of excluding
connections to loopback addresses, it affects only connections to
loopback addresses.

The whitespace in this commit is a bit nutty, in order to put whitespace
changes into a separate commit.
---
 doc/tor.1.txt       |   11 +++++++++++
 src/or/config.c     |   25 ++++++++++++++++---------
 src/or/connection.c |   17 ++++++++++-------
 src/or/or.h         |    6 ++++++
 4 files changed, 43 insertions(+), 16 deletions(-)

diff --git a/doc/tor.1.txt b/doc/tor.1.txt
index 1e1ff1e..f25234d 100644
--- a/doc/tor.1.txt
+++ b/doc/tor.1.txt
@@ -477,6 +477,17 @@ GENERAL OPTIONS
     This setting will be ignored for connections to the loopback addresses
     (127.0.0.0/8 and ::1).
 
+**LocalOutboundBindAddress** __IP__::
+    Like OutboundBindAddress, but _only_ for connections to loopback
+    addresses (e.g., inbound connections to local hidden services).
+    This is useful to distinguish Tor traffic from local traffic in
+    the log files of your hidden services. +
+ +
+    The IP should be in the 127.0.0.0/8 range for maximum compatibility.
+    I recommend using 127.84.111.114, since 84.111.114 is the ASCII
+    encoding of "Tor".  I also recommend adding \'127.84.111.114 tor' to
+    your /etc/hosts file.
+
 **PidFile** __FILE__::
     On startup, write our PID to FILE. On clean shutdown, remove
     FILE.
diff --git a/src/or/config.c b/src/or/config.c
index 206ccc8..03e07f9 100644
--- a/src/or/config.c
+++ b/src/or/config.c
@@ -285,6 +285,7 @@ static config_var_t option_vars_[] = {
   OBSOLETE("IgnoreVersion"),
   V(KeepalivePeriod,             INTERVAL, "5 minutes"),
   VAR("Log",                     LINELIST, Logs,             NULL),
+  V(LocalOutboundBindAddress,    LINELIST,   NULL),
   V(LogMessageDomains,           BOOL,     "0"),
   OBSOLETE("LinkPadding"),
   OBSOLETE("LogLevel"),
@@ -5556,15 +5557,20 @@ getinfo_helper_config(control_connection_t *conn,
 static int
 parse_outbound_addresses(or_options_t *options, int validate_only, char **msg)
 {
-  const config_line_t *lines = options->OutboundBindAddress;
-  int found_v4 = 0, found_v6 = 0;
+ int i;
+ for (i=0; i<2; ++i) {
+
+  tor_addr_t *out4 = i ? &options->OutboundBindAddressIPv4_ : &options->LocalOutboundBindAddressIPv4_;
+  tor_addr_t *out6 = i ? &options->OutboundBindAddressIPv6_ : &options->LocalOutboundBindAddressIPv6_;
 
   if (!validate_only) {
-    memset(&options->OutboundBindAddressIPv4_, 0,
-           sizeof(options->OutboundBindAddressIPv4_));
-    memset(&options->OutboundBindAddressIPv6_, 0,
-           sizeof(options->OutboundBindAddressIPv6_));
+    memset(out4, 0, sizeof(*out4));
+    memset(out6, 0, sizeof(*out6));
   }
+
+  const config_line_t *lines = i ? options->OutboundBindAddress : options->LocalOutboundBindAddress;
+  int found_v4 = 0, found_v6 = 0;
+
   while (lines) {
     tor_addr_t addr, *dst_addr = NULL;
     int af = tor_addr_parse(&addr, lines->value);
@@ -5577,7 +5583,7 @@ parse_outbound_addresses(or_options_t *options, int validate_only, char **msg)
         return -1;
       }
       found_v4 = 1;
-      dst_addr = &options->OutboundBindAddressIPv4_;
+      dst_addr = out4;
       break;
     case AF_INET6:
       if (found_v6) {
@@ -5587,7 +5593,7 @@ parse_outbound_addresses(or_options_t *options, int validate_only, char **msg)
         return -1;
       }
       found_v6 = 1;
-      dst_addr = &options->OutboundBindAddressIPv6_;
+      dst_addr = out6;
       break;
     default:
       if (msg)
@@ -5599,7 +5605,8 @@ parse_outbound_addresses(or_options_t *options, int validate_only, char **msg)
       tor_addr_copy(dst_addr, &addr);
     lines = lines->next;
   }
-  return 0;
+ }
+ return 0;
 }
 
 /** Load one of the geoip files, <a>family</a> determining which
diff --git a/src/or/connection.c b/src/or/connection.c
index dbcfc41..397a2dc 100644
--- a/src/or/connection.c
+++ b/src/or/connection.c
@@ -1451,14 +1451,17 @@ connection_connect(connection_t *conn, const char *address,
 
   make_socket_reuseable(s);
 
-  if (!tor_addr_is_loopback(addr)) {
+  {
+    const int is_local = tor_addr_is_loopback(addr);
     const tor_addr_t *ext_addr = NULL;
-    if (protocol_family == AF_INET &&
-        !tor_addr_is_null(&options->OutboundBindAddressIPv4_))
-      ext_addr = &options->OutboundBindAddressIPv4_;
-    else if (protocol_family == AF_INET6 &&
-             !tor_addr_is_null(&options->OutboundBindAddressIPv6_))
-      ext_addr = &options->OutboundBindAddressIPv6_;
+    const tor_addr_t *maybe_ext_addr4 = is_local ? &options->LocalOutboundBindAddressIPv4_ : &options->OutboundBindAddressIPv4_;
+    const tor_addr_t *maybe_ext_addr6 = is_local ? &options->LocalOutboundBindAddressIPv6_ : &options->OutboundBindAddressIPv6_;
+
+    if (protocol_family == AF_INET && !tor_addr_is_null(maybe_ext_addr4))
+      ext_addr = maybe_ext_addr4;
+    else if (protocol_family == AF_INET6 && !tor_addr_is_null(maybe_ext_addr6))
+      ext_addr = maybe_ext_addr6;
+
     if (ext_addr) {
       struct sockaddr_storage ext_addr_sa;
       socklen_t ext_addr_len = 0;
diff --git a/src/or/or.h b/src/or/or.h
index a8645f8..a832e4f 100644
--- a/src/or/or.h
+++ b/src/or/or.h
@@ -3181,6 +3181,12 @@ typedef struct {
   tor_addr_t OutboundBindAddressIPv4_;
   /** IPv6 address derived from OutboundBindAddress. */
   tor_addr_t OutboundBindAddressIPv6_;
+  /** Local address to bind outbound sockets -- for loopback connections (e.g., hidden services) */
+  config_line_t *LocalOutboundBindAddress;
+  /** IPv4 address derived from LocalOutboundBindAddress. */
+  tor_addr_t LocalOutboundBindAddressIPv4_;
+  /** IPv6 address derived from LocalOutboundBindAddress. */
+  tor_addr_t LocalOutboundBindAddressIPv6_;
   /** Directory server only: which versions of
    * Tor should we tell users to run? */
   config_line_t *RecommendedVersions;
-- 
1.7.10.4