[tor-commits] [tor/master] Add new option ClientAutoIPv6ORPort to switch between IPv4 and IPv6 OR ports
nickm at torproject.org
nickm at torproject.org
Sun Dec 2 01:32:25 UTC 2018
commit 822cb93cab59e9735e2efda70bc88c47cc92c498
Author: Neel Chauhan <neel at neelc.org>
Date: Wed Sep 26 19:14:33 2018 -0400
Add new option ClientAutoIPv6ORPort to switch between IPv4 and IPv6 OR ports
---
changes/ticket27490 | 6 ++++++
doc/tor.1.txt | 6 ++++++
src/app/config/config.c | 1 +
src/app/config/or_options_st.h | 3 +++
src/core/mainloop/connection.c | 5 +++++
src/core/or/policies.c | 15 ++++++++++++++-
src/feature/client/bridges.c | 3 ++-
7 files changed, 37 insertions(+), 2 deletions(-)
diff --git a/changes/ticket27490 b/changes/ticket27490
new file mode 100644
index 000000000..523477dfe
--- /dev/null
+++ b/changes/ticket27490
@@ -0,0 +1,6 @@
+ o Minor features (ipv6):
+ - We add an option ClientAutoIPv6ORPort which makes clients randomly
+ prefer a node's IPv4 or IPv6 ORPort. The random preference is set
+ every time a node is loaded from a new consensus or bridge config.
+ Closes ticket 27490. Patch by Neel Chauhan.
+
diff --git a/doc/tor.1.txt b/doc/tor.1.txt
index 406372433..bd4dbbcbd 100644
--- a/doc/tor.1.txt
+++ b/doc/tor.1.txt
@@ -1748,6 +1748,12 @@ The following options are useful only for clients (that is, if
other clients prefer IPv4. Other things may influence the choice. This
option breaks a tie to the favor of IPv6. (Default: auto)
+[[ClientAutoIPv6ORPort]] **ClientAutoIPv6ORPort** **0**|**1**::
+ If this option is set to 1, Tor clients randomly prefer a node's IPv4 or
+ IPv6 ORPort. The random preference is set every time a node is loaded
+ from a new consensus or bridge config. When this option is set to 1,
+ **ClientPreferIPv6ORPort** is ignored. (Default: 0)
+
[[PathsNeededToBuildCircuits]] **PathsNeededToBuildCircuits** __NUM__::
Tor clients don't build circuits for user traffic until they know
about enough of the network so that they could potentially construct
diff --git a/src/app/config/config.c b/src/app/config/config.c
index 01b48e3c5..6a510c56d 100644
--- a/src/app/config/config.c
+++ b/src/app/config/config.c
@@ -332,6 +332,7 @@ static config_var_t option_vars_[] = {
V(ClientOnly, BOOL, "0"),
V(ClientPreferIPv6ORPort, AUTOBOOL, "auto"),
V(ClientPreferIPv6DirPort, AUTOBOOL, "auto"),
+ V(ClientAutoIPv6ORPort, BOOL, "0"),
V(ClientRejectInternalAddresses, BOOL, "1"),
V(ClientTransportPlugin, LINELIST, NULL),
V(ClientUseIPv6, BOOL, "0"),
diff --git a/src/app/config/or_options_st.h b/src/app/config/or_options_st.h
index 3524b99b5..ff3d30d7e 100644
--- a/src/app/config/or_options_st.h
+++ b/src/app/config/or_options_st.h
@@ -666,6 +666,9 @@ struct or_options_t {
* accessing this value directly. */
int ClientPreferIPv6DirPort;
+ /** If true, prefer an IPv4 or IPv6 OR port at random. */
+ int ClientAutoIPv6ORPort;
+
/** The length of time that we think a consensus should be fresh. */
int V3AuthVotingInterval;
/** The length of time we think it will take to distribute votes. */
diff --git a/src/core/mainloop/connection.c b/src/core/mainloop/connection.c
index 4231bec01..9f8169082 100644
--- a/src/core/mainloop/connection.c
+++ b/src/core/mainloop/connection.c
@@ -2069,6 +2069,11 @@ connection_connect_log_client_use_ip_version(const connection_t *conn)
return;
}
+ if (fascist_firewall_use_ipv6(options)) {
+ log_info(LD_NET, "Our outgoing connection is using IPv%d.",
+ tor_addr_family(&real_addr) == AF_INET6 ? 6 : 4);
+ }
+
/* Check if we couldn't satisfy an address family preference */
if ((!pref_ipv6 && tor_addr_family(&real_addr) == AF_INET6)
|| (pref_ipv6 && tor_addr_family(&real_addr) == AF_INET)) {
diff --git a/src/core/or/policies.c b/src/core/or/policies.c
index 3443a1710..e51a49cf6 100644
--- a/src/core/or/policies.c
+++ b/src/core/or/policies.c
@@ -28,6 +28,7 @@
#include "feature/nodelist/routerparse.h"
#include "feature/stats/geoip.h"
#include "ht.h"
+#include "lib/crypt_ops/crypto_rand.h"
#include "lib/encoding/confline.h"
#include "core/or/addr_policy_st.h"
@@ -487,6 +488,15 @@ fascist_firewall_prefer_ipv6_impl(const or_options_t *options)
return -1;
}
+/* Choose whether we prefer IPv4 or IPv6 by randomly choosing an address
+ * family. Return 0 for IPv4, and 1 for IPv6. */
+static int
+fascist_firewall_rand_prefer_ipv6_addr(void)
+{
+ /* TODO: Check for failures, and infer our preference based on this. */
+ return crypto_rand_int(2);
+}
+
/** Do we prefer to connect to IPv6 ORPorts?
* Use node_ipv6_or_preferred() whenever possible: it supports bridge client
* per-node IPv6 preferences.
@@ -501,7 +511,10 @@ fascist_firewall_prefer_ipv6_orport(const or_options_t *options)
}
/* We can use both IPv4 and IPv6 - which do we prefer? */
- if (options->ClientPreferIPv6ORPort == 1) {
+ if (options->ClientAutoIPv6ORPort == 1) {
+ /* If ClientAutoIPv6ORPort is 1, we prefer IPv4 or IPv6 at random. */
+ return fascist_firewall_rand_prefer_ipv6_addr();
+ } else if (options->ClientPreferIPv6ORPort == 1) {
return 1;
}
diff --git a/src/feature/client/bridges.c b/src/feature/client/bridges.c
index e8afb5a92..e3ed28841 100644
--- a/src/feature/client/bridges.c
+++ b/src/feature/client/bridges.c
@@ -844,7 +844,8 @@ rewrite_node_address_for_bridge(const bridge_info_t *bridge, node_t *node)
}
}
- if (options->ClientPreferIPv6ORPort == -1) {
+ if (options->ClientPreferIPv6ORPort == -1 ||
+ options->ClientAutoIPv6ORPort == 0) {
/* Mark which address to use based on which bridge_t we got. */
node->ipv6_preferred = (tor_addr_family(&bridge->addr) == AF_INET6 &&
!tor_addr_is_null(&node->ri->ipv6_addr));
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