Clients connect to public relays over IPv6.

Add ClientUseIPv6 and ClientPreferIPv6ORPort configuration options.

Use "preferred OR port" for all entry nodes, not only for bridges.

Mark bridges with "prefer IPv6 OR port" if an IPv6 address is
configured in Bridge line and ClientPreferIPv6ORPort is set.

Mark relays with "prefer IPv6 OR port" if an IPv6 address is found in
descriptor and ClientPreferIPv6ORPort is set.

Filter "preferred OR port" through the ClientUseIPv6 config option. We
might want to move this test to where actual connection is being set
up once we have a fall back mechanism in place.

Have only non-servers pick an IPv6 address for the first hop: We
don't want relays to connect over IPv6 yet. (IPv6 has never been used
for second or third hops.)

Implements ticket 5535.

1 files changed, 12 insertions, 0 deletions

diff --git a/doc/tor.1.txt b/doc/tor.1.txt
index aa9303c2fb..68898eb88f 100644
--- a/doc/tor.1.txt
+++ b/doc/tor.1.txt
@@ -1171,6 +1171,18 @@ The following options are useful only for clients (that is, if
     If no defaults are available there, these options default to 20, .70,
     0.0, 200, and 4 respectively.
 
+**ClientUseIPv6** **0**|**1**::
+    If this option is set to 1, Tor might connect to entry nodes over
+    IPv6. Note that clients configured with an IPv6 address in a
+    **Bridge** option will try connecting over IPv6 if even if
+    **ClientUseIPv6** is set to 0. (Default: 0)
+
+**ClientPreferIPv6ORPort** **0**|**1**::
+    If this option is set to 1, Tor prefers an OR port with an IPv6
+    address over one with IPv4 if a given entry node has both. Other
+    things may influence the choice. This option breaks a tie to the
+    favor of IPv6. (Default: 0)
+
 
 SERVER OPTIONS
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