Add ClientUseIPv4 and ClientPreferIPv6DirPort torrc options

ClientUseIPv4 0 tells tor to avoid IPv4 client connections.
ClientPreferIPv6DirPort 1 tells tor to prefer IPv6 directory connections.

Refactor policy for IPv4/IPv6 preferences.

Fix a bug where node->ipv6_preferred could become stale if
ClientPreferIPv6ORPort was changed after the consensus was loaded.

Update documentation, existing code, add unit tests.

2 files changed, 544 insertions, 0 deletions

diff --git a/src/test/test_entrynodes.c b/src/test/test_entrynodes.c
index 0011d3698a..87276dbbf8 100644
--- a/src/test/test_entrynodes.c
+++ b/src/test/test_entrynodes.c
@@ -624,6 +624,100 @@ test_entry_is_live(void *arg)
   ; /* XXX */
 }
 
+static or_options_t mocked_options;
+
+static const or_options_t *
+mock_get_options(void)
+{
+  return &mocked_options;
+}
+
+#define TEST_IPV4_ADDR "123.45.67.89"
+#define TEST_IPV6_ADDR "[1234:5678:90ab:cdef::]"
+
+static void
+test_node_preferred_orport(void *arg)
+{
+  (void)arg;
+  tor_addr_t ipv4_addr;
+  const uint16_t ipv4_port = 4444;
+  tor_addr_t ipv6_addr;
+  const uint16_t ipv6_port = 6666;
+  routerinfo_t node_ri;
+  node_t node;
+  tor_addr_port_t ap;
+
+  /* Setup options */
+  memset(&mocked_options, 0, sizeof(mocked_options));
+  /* We don't test ClientPreferIPv6ORPort here, because it's only used in
+   * nodelist_set_consensus to setup each node_t. */
+  MOCK(get_options, mock_get_options);
+
+  /* Setup IP addresses */
+  tor_addr_parse(&ipv4_addr, TEST_IPV4_ADDR);
+  tor_addr_parse(&ipv6_addr, TEST_IPV6_ADDR);
+
+  /* Setup node_ri */
+  memset(&node_ri, 0, sizeof(node_ri));
+  node_ri.addr = tor_addr_to_ipv4h(&ipv4_addr);
+  node_ri.or_port = ipv4_port;
+  tor_addr_copy(&node_ri.ipv6_addr, &ipv6_addr);
+  node_ri.ipv6_orport = ipv6_port;
+
+  /* Setup node */
+  memset(&node, 0, sizeof(node));
+  node.ri = &node_ri;
+
+  /* Check the preferred address is IPv4 if we're only using IPv4, regardless
+   * of whether we prefer it or not */
+  mocked_options.ClientUseIPv4 = 1;
+  mocked_options.ClientUseIPv6 = 0;
+  node.ipv6_preferred = 0;
+  node_get_pref_orport(&node, &ap);
+  tt_assert(tor_addr_eq(&ap.addr, &ipv4_addr));
+  tt_assert(ap.port == ipv4_port);
+
+  node.ipv6_preferred = 1;
+  node_get_pref_orport(&node, &ap);
+  tt_assert(tor_addr_eq(&ap.addr, &ipv4_addr));
+  tt_assert(ap.port == ipv4_port);
+
+  /* Check the preferred address is IPv4 if we're using IPv4 and IPv6, but
+   * don't prefer the IPv6 address */
+  mocked_options.ClientUseIPv4 = 1;
+  mocked_options.ClientUseIPv6 = 1;
+  node.ipv6_preferred = 0;
+  node_get_pref_orport(&node, &ap);
+  tt_assert(tor_addr_eq(&ap.addr, &ipv4_addr));
+  tt_assert(ap.port == ipv4_port);
+
+  /* Check the preferred address is IPv6 if we prefer it and
+   * ClientUseIPv6 is 1, regardless of ClientUseIPv4 */
+  mocked_options.ClientUseIPv4 = 1;
+  mocked_options.ClientUseIPv6 = 1;
+  node.ipv6_preferred = 1;
+  node_get_pref_orport(&node, &ap);
+  tt_assert(tor_addr_eq(&ap.addr, &ipv6_addr));
+  tt_assert(ap.port == ipv6_port);
+
+  mocked_options.ClientUseIPv4 = 0;
+  node_get_pref_orport(&node, &ap);
+  tt_assert(tor_addr_eq(&ap.addr, &ipv6_addr));
+  tt_assert(ap.port == ipv6_port);
+
+  /* Check the preferred address is IPv6 if we don't prefer it, but
+   * ClientUseIPv4 is 0 */
+  mocked_options.ClientUseIPv4 = 0;
+  mocked_options.ClientUseIPv6 = 1;
+  node.ipv6_preferred = 0;
+  node_get_pref_orport(&node, &ap);
+  tt_assert(tor_addr_eq(&ap.addr, &ipv6_addr));
+  tt_assert(ap.port == ipv6_port);
+
+ done:
+  UNMOCK(get_options);
+}
+
 static const struct testcase_setup_t fake_network = {
   fake_network_setup, fake_network_cleanup
 };
@@ -654,6 +748,9 @@ struct testcase_t entrynodes_tests[] = {
   { "entry_is_live",
     test_entry_is_live,
     TT_FORK, &fake_network, NULL },
+  { "node_preferred_orport",
+    test_node_preferred_orport,
+    0, NULL, NULL },
   END_OF_TESTCASES
 };
 
diff --git a/src/test/test_policy.c b/src/test/test_policy.c
index 4f5565e575..077d1b2af5 100644
--- a/src/test/test_policy.c
+++ b/src/test/test_policy.c
@@ -1127,6 +1127,449 @@ test_policies_getinfo_helper_policies(void *arg)
 #undef TEST_IPV4_ADDR
 #undef TEST_IPV6_ADDR
 
+#define TEST_IPV4_ADDR_STR "1.2.3.4"
+#define TEST_IPV6_ADDR_STR "[1002::4567]"
+#define REJECT_IPv4_FINAL_STR "reject 0.0.0.0/0:*"
+#define REJECT_IPv6_FINAL_STR "reject [::]/0:*"
+
+#define OTHER_IPV4_ADDR_STR "6.7.8.9"
+#define OTHER_IPV6_ADDR_STR "[afff::]"
+
+/** Run unit tests for fascist_firewall_allows_address */
+static void
+test_policies_fascist_firewall_allows_address(void *arg)
+{
+  (void)arg;
+  tor_addr_t ipv4_addr, ipv6_addr, r_ipv4_addr, r_ipv6_addr;
+  tor_addr_t n_ipv4_addr, n_ipv6_addr;
+  const uint16_t port = 1234;
+  smartlist_t *policy = NULL;
+  smartlist_t *e_policy = NULL;
+  addr_policy_t *item = NULL;
+  int malformed_list = 0;
+
+  /* Setup the options and the items in the policies */
+  memset(&mock_options, 0, sizeof(or_options_t));
+  MOCK(get_options, mock_get_options);
+
+  policy = smartlist_new();
+  item = router_parse_addr_policy_item_from_string("accept "
+                                                   TEST_IPV4_ADDR_STR ":*",
+                                                   ADDR_POLICY_ACCEPT,
+                                                   &malformed_list);
+  tt_assert(item);
+  tt_assert(!malformed_list);
+  smartlist_add(policy, item);
+  item = router_parse_addr_policy_item_from_string("accept "
+                                                   TEST_IPV6_ADDR_STR,
+                                                   ADDR_POLICY_ACCEPT,
+                                                   &malformed_list);
+  tt_assert(item);
+  tt_assert(!malformed_list);
+  smartlist_add(policy, item);
+  /* Normally, policy_expand_unspec would do this for us */
+  item = router_parse_addr_policy_item_from_string(REJECT_IPv4_FINAL_STR,
+                                                   ADDR_POLICY_ACCEPT,
+                                                   &malformed_list);
+  tt_assert(item);
+  tt_assert(!malformed_list);
+  smartlist_add(policy, item);
+  item = router_parse_addr_policy_item_from_string(REJECT_IPv6_FINAL_STR,
+                                                   ADDR_POLICY_ACCEPT,
+                                                   &malformed_list);
+  tt_assert(item);
+  tt_assert(!malformed_list);
+  smartlist_add(policy, item);
+  item = NULL;
+
+  e_policy = smartlist_new();
+
+  /*
+  char *polstr = policy_dump_to_string(policy, 1, 1);
+  printf("%s\n", polstr);
+  tor_free(polstr);
+   */
+
+  /* Parse the addresses */
+  tor_addr_parse(&ipv4_addr, TEST_IPV4_ADDR_STR);
+  tor_addr_parse(&ipv6_addr, TEST_IPV6_ADDR_STR);
+  tor_addr_parse(&r_ipv4_addr, OTHER_IPV4_ADDR_STR);
+  tor_addr_parse(&r_ipv6_addr, OTHER_IPV6_ADDR_STR);
+  tor_addr_make_null(&n_ipv4_addr, AF_INET);
+  tor_addr_make_null(&n_ipv6_addr, AF_INET6);
+
+  /* Test the function's address matching with IPv4 and IPv6 on */
+  memset(&mock_options, 0, sizeof(or_options_t));
+  mock_options.ClientUseIPv4 = 1;
+  mock_options.ClientUseIPv6 = 1;
+  mock_options.UseBridges = 0;
+
+  tt_assert(fascist_firewall_allows_address(&ipv4_addr, port, policy, 0, 0)
+            == 1);
+  tt_assert(fascist_firewall_allows_address(&ipv6_addr, port, policy, 0, 0)
+            == 1);
+  tt_assert(fascist_firewall_allows_address(&r_ipv4_addr, port, policy, 0, 0)
+            == 0);
+  tt_assert(fascist_firewall_allows_address(&r_ipv6_addr, port, policy, 0, 0)
+            == 0);
+
+  /* Preferring IPv4 */
+  tt_assert(fascist_firewall_allows_address(&ipv4_addr, port, policy, 1, 0)
+            == 1);
+  tt_assert(fascist_firewall_allows_address(&ipv6_addr, port, policy, 1, 0)
+            == 0);
+  tt_assert(fascist_firewall_allows_address(&r_ipv4_addr, port, policy, 1, 0)
+            == 0);
+  tt_assert(fascist_firewall_allows_address(&r_ipv6_addr, port, policy, 1, 0)
+            == 0);
+
+  /* Preferring IPv6 */
+  tt_assert(fascist_firewall_allows_address(&ipv4_addr, port, policy, 1, 1)
+            == 0);
+  tt_assert(fascist_firewall_allows_address(&ipv6_addr, port, policy, 1, 1)
+            == 1);
+  tt_assert(fascist_firewall_allows_address(&r_ipv4_addr, port, policy, 1, 1)
+            == 0);
+  tt_assert(fascist_firewall_allows_address(&r_ipv6_addr, port, policy, 1, 1)
+            == 0);
+
+  /* Test the function's address matching with UseBridges on */
+  memset(&mock_options, 0, sizeof(or_options_t));
+  mock_options.ClientUseIPv4 = 0;
+  mock_options.ClientUseIPv6 = 0;
+  mock_options.UseBridges = 1;
+
+  tt_assert(fascist_firewall_allows_address(&ipv4_addr, port, policy, 0, 0)
+            == 1);
+  tt_assert(fascist_firewall_allows_address(&ipv6_addr, port, policy, 0, 0)
+            == 1);
+  tt_assert(fascist_firewall_allows_address(&r_ipv4_addr, port, policy, 0, 0)
+            == 0);
+  tt_assert(fascist_firewall_allows_address(&r_ipv6_addr, port, policy, 0, 0)
+            == 0);
+
+  /* Test the function's address matching with IPv4 on */
+  memset(&mock_options, 0, sizeof(or_options_t));
+  mock_options.ClientUseIPv4 = 1;
+  mock_options.ClientUseIPv6 = 0;
+  mock_options.UseBridges = 0;
+
+  tt_assert(fascist_firewall_allows_address(&ipv4_addr, port, policy, 0, 0)
+            == 1);
+  tt_assert(fascist_firewall_allows_address(&ipv6_addr, port, policy, 0, 0)
+            == 0);
+  tt_assert(fascist_firewall_allows_address(&r_ipv4_addr, port, policy, 0, 0)
+            == 0);
+  tt_assert(fascist_firewall_allows_address(&r_ipv6_addr, port, policy, 0, 0)
+            == 0);
+
+  /* Test the function's address matching with IPv6 on */
+  memset(&mock_options, 0, sizeof(or_options_t));
+  mock_options.ClientUseIPv4 = 0;
+  mock_options.ClientUseIPv6 = 1;
+  mock_options.UseBridges = 0;
+
+  tt_assert(fascist_firewall_allows_address(&ipv4_addr, port, policy, 0, 0)
+            == 0);
+  tt_assert(fascist_firewall_allows_address(&ipv6_addr, port, policy, 0, 0)
+            == 1);
+  tt_assert(fascist_firewall_allows_address(&r_ipv4_addr, port, policy, 0, 0)
+            == 0);
+  tt_assert(fascist_firewall_allows_address(&r_ipv6_addr, port, policy, 0, 0)
+            == 0);
+
+  /* Test the function's address matching with everything off */
+  memset(&mock_options, 0, sizeof(or_options_t));
+  mock_options.ClientUseIPv4 = 0;
+  mock_options.ClientUseIPv6 = 0;
+  mock_options.UseBridges = 0;
+
+  tt_assert(fascist_firewall_allows_address(&ipv4_addr, port, policy, 0, 0)
+            == 0);
+  tt_assert(fascist_firewall_allows_address(&ipv6_addr, port, policy, 0, 0)
+            == 0);
+  tt_assert(fascist_firewall_allows_address(&r_ipv4_addr, port, policy, 0, 0)
+            == 0);
+  tt_assert(fascist_firewall_allows_address(&r_ipv6_addr, port, policy, 0, 0)
+            == 0);
+
+  /* Test the function's address matching for unusual inputs */
+  memset(&mock_options, 0, sizeof(or_options_t));
+  mock_options.ClientUseIPv4 = 1;
+  mock_options.ClientUseIPv6 = 1;
+  mock_options.UseBridges = 1;
+
+  /* NULL and tor_addr_is_null addresses are rejected */
+  tt_assert(fascist_firewall_allows_address(NULL, port, policy, 0, 0) == 0);
+  tt_assert(fascist_firewall_allows_address(&n_ipv4_addr, port, policy, 0, 0)
+            == 0);
+  tt_assert(fascist_firewall_allows_address(&n_ipv6_addr, port, policy, 0, 0)
+            == 0);
+
+  /* zero ports are rejected */
+  tt_assert(fascist_firewall_allows_address(&ipv4_addr, 0, policy, 0, 0)
+            == 0);
+  tt_assert(fascist_firewall_allows_address(&ipv6_addr, 0, policy, 0, 0)
+            == 0);
+
+  /* NULL and empty policies accept everything */
+  tt_assert(fascist_firewall_allows_address(&ipv4_addr, port, NULL, 0, 0)
+            == 1);
+  tt_assert(fascist_firewall_allows_address(&ipv6_addr, port, NULL, 0, 0)
+            == 1);
+  tt_assert(fascist_firewall_allows_address(&ipv4_addr, port, e_policy, 0, 0)
+            == 1);
+  tt_assert(fascist_firewall_allows_address(&ipv6_addr, port, e_policy, 0, 0)
+            == 1);
+
+ done:
+  addr_policy_free(item);
+  addr_policy_list_free(policy);
+  addr_policy_list_free(e_policy);
+  UNMOCK(get_options);
+}
+
+#undef REJECT_IPv4_FINAL_STR
+#undef REJECT_IPv6_FINAL_STR
+#undef OTHER_IPV4_ADDR_STR
+#undef OTHER_IPV6_ADDR_STR
+
+#define TEST_IPV4_OR_PORT  1234
+#define TEST_IPV4_DIR_PORT 2345
+#define TEST_IPV6_OR_PORT  61234
+#define TEST_IPV6_DIR_PORT 62345
+
+/** Run unit tests for fascist_firewall_choose_address */
+static void
+test_policies_fascist_firewall_choose_address(void *arg)
+{
+  (void)arg;
+  tor_addr_port_t ipv4_or_ap, ipv4_dir_ap, ipv6_or_ap, ipv6_dir_ap;
+  tor_addr_port_t n_ipv4_ap, n_ipv6_ap;
+
+  /* Setup the options */
+  memset(&mock_options, 0, sizeof(or_options_t));
+  MOCK(get_options, mock_get_options);
+
+  /* Parse the addresses */
+  tor_addr_parse(&ipv4_or_ap.addr, TEST_IPV4_ADDR_STR);
+  ipv4_or_ap.port = TEST_IPV4_OR_PORT;
+  tor_addr_parse(&ipv4_dir_ap.addr, TEST_IPV4_ADDR_STR);
+  ipv4_dir_ap.port = TEST_IPV4_DIR_PORT;
+
+  tor_addr_parse(&ipv6_or_ap.addr, TEST_IPV6_ADDR_STR);
+  ipv6_or_ap.port = TEST_IPV6_OR_PORT;
+  tor_addr_parse(&ipv6_dir_ap.addr, TEST_IPV6_ADDR_STR);
+  ipv6_dir_ap.port = TEST_IPV6_DIR_PORT;
+
+  tor_addr_make_null(&n_ipv4_ap.addr, AF_INET);
+  n_ipv4_ap.port = 0;
+  tor_addr_make_null(&n_ipv6_ap.addr, AF_INET6);
+  n_ipv6_ap.port = 0;
+
+  /* Choose an address with IPv4 and IPv6 on */
+  memset(&mock_options, 0, sizeof(or_options_t));
+  mock_options.ClientUseIPv4 = 1;
+  mock_options.ClientUseIPv6 = 1;
+  mock_options.UseBridges = 0;
+
+  /* Preferring IPv4 */
+  mock_options.ClientPreferIPv6ORPort = 0;
+  mock_options.ClientPreferIPv6DirPort = 0;
+  tt_assert(fascist_firewall_choose_address(&ipv4_or_ap, &ipv6_or_ap, 0,
+                                                 FIREWALL_OR_CONNECTION, 0)
+            == &ipv4_or_ap);
+  tt_assert(fascist_firewall_choose_address(&ipv4_or_ap, &ipv6_or_ap, 0,
+                                                 FIREWALL_OR_CONNECTION, 1)
+            == &ipv4_or_ap);
+  tt_assert(fascist_firewall_choose_address(&ipv4_dir_ap, &ipv6_dir_ap, 0,
+                                                 FIREWALL_DIR_CONNECTION, 0)
+            == &ipv4_dir_ap);
+  tt_assert(fascist_firewall_choose_address(&ipv4_dir_ap, &ipv6_dir_ap, 0,
+                                                 FIREWALL_DIR_CONNECTION, 1)
+            == &ipv4_dir_ap);
+
+  /* Preferring IPv6 */
+  mock_options.ClientPreferIPv6ORPort = 1;
+  mock_options.ClientPreferIPv6DirPort = 1;
+  tt_assert(fascist_firewall_choose_address(&ipv4_or_ap, &ipv6_or_ap, 0,
+                                                 FIREWALL_OR_CONNECTION, 0)
+            == &ipv6_or_ap);
+  tt_assert(fascist_firewall_choose_address(&ipv4_or_ap, &ipv6_or_ap, 0,
+                                                 FIREWALL_OR_CONNECTION, 1)
+            == &ipv6_or_ap);
+  tt_assert(fascist_firewall_choose_address(&ipv4_dir_ap, &ipv6_dir_ap, 0,
+                                                 FIREWALL_DIR_CONNECTION, 0)
+            == &ipv6_dir_ap);
+  tt_assert(fascist_firewall_choose_address(&ipv4_dir_ap, &ipv6_dir_ap, 0,
+                                                 FIREWALL_DIR_CONNECTION, 1)
+            == &ipv6_dir_ap);
+
+  /* Preferring IPv4 OR / IPv6 Dir */
+  mock_options.ClientPreferIPv6ORPort = 0;
+  mock_options.ClientPreferIPv6DirPort = 1;
+  tt_assert(fascist_firewall_choose_address(&ipv4_or_ap, &ipv6_or_ap, 0,
+                                                 FIREWALL_OR_CONNECTION, 0)
+            == &ipv4_or_ap);
+  tt_assert(fascist_firewall_choose_address(&ipv4_or_ap, &ipv6_or_ap, 0,
+                                                 FIREWALL_OR_CONNECTION, 1)
+            == &ipv4_or_ap);
+  tt_assert(fascist_firewall_choose_address(&ipv4_dir_ap, &ipv6_dir_ap, 0,
+                                                 FIREWALL_DIR_CONNECTION, 0)
+            == &ipv6_dir_ap);
+  tt_assert(fascist_firewall_choose_address(&ipv4_dir_ap, &ipv6_dir_ap, 0,
+                                                 FIREWALL_DIR_CONNECTION, 1)
+            == &ipv6_dir_ap);
+
+  /* Preferring IPv6 OR / IPv4 Dir */
+  mock_options.ClientPreferIPv6ORPort = 1;
+  mock_options.ClientPreferIPv6DirPort = 0;
+  tt_assert(fascist_firewall_choose_address(&ipv4_or_ap, &ipv6_or_ap, 0,
+                                                 FIREWALL_OR_CONNECTION, 0)
+            == &ipv6_or_ap);
+  tt_assert(fascist_firewall_choose_address(&ipv4_or_ap, &ipv6_or_ap, 0,
+                                                 FIREWALL_OR_CONNECTION, 1)
+            == &ipv6_or_ap);
+  tt_assert(fascist_firewall_choose_address(&ipv4_dir_ap, &ipv6_dir_ap, 0,
+                                                 FIREWALL_DIR_CONNECTION, 0)
+            == &ipv4_dir_ap);
+  tt_assert(fascist_firewall_choose_address(&ipv4_dir_ap, &ipv6_dir_ap, 0,
+                                                 FIREWALL_DIR_CONNECTION, 1)
+            == &ipv4_dir_ap);
+
+  /* Choose an address with UseBridges on */
+  memset(&mock_options, 0, sizeof(or_options_t));
+  mock_options.UseBridges = 1;
+
+  for (mock_options.ClientUseIPv4 = 0; mock_options.ClientUseIPv4 <= 1;
+       mock_options.ClientUseIPv4++) {
+    for (mock_options.ClientUseIPv6 = 0; mock_options.ClientUseIPv6 <= 1;
+         mock_options.ClientUseIPv6++) {
+      for (mock_options.ClientPreferIPv6ORPort = 0;
+           mock_options.ClientPreferIPv6ORPort <= 1;
+           mock_options.ClientPreferIPv6ORPort++) {
+        for (mock_options.ClientPreferIPv6DirPort = 0;
+             mock_options.ClientPreferIPv6DirPort <= 1;
+             mock_options.ClientPreferIPv6DirPort++) {
+          /* This (ab)uses the actual enum values */
+          tt_assert(FIREWALL_OR_CONNECTION < FIREWALL_DIR_CONNECTION);
+          for (firewall_connection_t fw_connection = FIREWALL_OR_CONNECTION;
+               fw_connection <= FIREWALL_DIR_CONNECTION; fw_connection++) {
+            for (int pref_only = 0; pref_only <= 1; pref_only++) {
+
+              /* Ignoring all other settings, want_a should choose the address
+               * for bridge clients */
+              tt_assert(fascist_firewall_choose_address(&ipv4_or_ap,
+                                                             &ipv6_or_ap, 1,
+                                                             fw_connection,
+                                                             pref_only)
+                        == &ipv4_or_ap);
+              tt_assert(fascist_firewall_choose_address(&ipv4_or_ap,
+                                                             &ipv6_or_ap, 0,
+                                                             fw_connection,
+                                                             pref_only)
+                        == &ipv6_or_ap);
+            }
+          }
+        }
+      }
+    }
+  }
+
+  /* Choose an address with IPv4 on */
+  memset(&mock_options, 0, sizeof(or_options_t));
+  mock_options.ClientUseIPv4 = 1;
+  mock_options.ClientUseIPv6 = 0;
+  mock_options.UseBridges = 0;
+
+  tt_assert(fascist_firewall_choose_address(&ipv4_or_ap, &ipv6_or_ap, 0,
+                                                 FIREWALL_OR_CONNECTION, 0)
+            == &ipv4_or_ap);
+  tt_assert(fascist_firewall_choose_address(&ipv4_or_ap, &ipv6_or_ap, 0,
+                                                 FIREWALL_OR_CONNECTION, 1)
+            == &ipv4_or_ap);
+  tt_assert(fascist_firewall_choose_address(&ipv4_dir_ap, &ipv6_dir_ap, 0,
+                                                 FIREWALL_DIR_CONNECTION, 0)
+            == &ipv4_dir_ap);
+  tt_assert(fascist_firewall_choose_address(&ipv4_dir_ap, &ipv6_dir_ap, 0,
+                                                 FIREWALL_DIR_CONNECTION, 1)
+            == &ipv4_dir_ap);
+
+  /* Choose an address with IPv6 on */
+  memset(&mock_options, 0, sizeof(or_options_t));
+  mock_options.ClientUseIPv4 = 0;
+  mock_options.ClientUseIPv6 = 1;
+  mock_options.UseBridges = 0;
+
+  tt_assert(fascist_firewall_choose_address(&ipv4_or_ap, &ipv6_or_ap, 0,
+                                                 FIREWALL_OR_CONNECTION, 0)
+            == &ipv6_or_ap);
+  tt_assert(fascist_firewall_choose_address(&ipv4_or_ap, &ipv6_or_ap, 0,
+                                                 FIREWALL_OR_CONNECTION, 1)
+            == &ipv6_or_ap);
+  tt_assert(fascist_firewall_choose_address(&ipv4_dir_ap, &ipv6_dir_ap, 0,
+                                                 FIREWALL_DIR_CONNECTION, 0)
+            == &ipv6_dir_ap);
+  tt_assert(fascist_firewall_choose_address(&ipv4_dir_ap, &ipv6_dir_ap, 0,
+                                                 FIREWALL_DIR_CONNECTION, 1)
+            == &ipv6_dir_ap);
+
+  /* Choose an address with everything off */
+  memset(&mock_options, 0, sizeof(or_options_t));
+  mock_options.ClientUseIPv4 = 0;
+  mock_options.ClientUseIPv6 = 0;
+  mock_options.UseBridges = 0;
+
+  tt_assert(fascist_firewall_choose_address(&ipv4_or_ap, &ipv6_or_ap, 0,
+                                                 FIREWALL_OR_CONNECTION, 0)
+            == NULL);
+  tt_assert(fascist_firewall_choose_address(&ipv4_or_ap, &ipv6_or_ap, 0,
+                                                 FIREWALL_OR_CONNECTION, 1)
+            == NULL);
+  tt_assert(fascist_firewall_choose_address(&ipv4_dir_ap, &ipv6_dir_ap, 0,
+                                                 FIREWALL_DIR_CONNECTION, 0)
+            == NULL);
+  tt_assert(fascist_firewall_choose_address(&ipv4_dir_ap, &ipv6_dir_ap, 0,
+                                                 FIREWALL_DIR_CONNECTION, 1)
+            == NULL);
+
+  /* Choose from unusual inputs */
+  memset(&mock_options, 0, sizeof(or_options_t));
+  mock_options.ClientUseIPv4 = 1;
+  mock_options.ClientUseIPv6 = 1;
+  mock_options.UseBridges = 1;
+
+  tt_assert(fascist_firewall_choose_address(&ipv4_or_ap, &n_ipv6_ap, 0,
+                                                 FIREWALL_OR_CONNECTION, 0)
+            == &ipv4_or_ap);
+  tt_assert(fascist_firewall_choose_address(&n_ipv4_ap, &ipv6_or_ap, 0,
+                                                 FIREWALL_OR_CONNECTION, 0)
+            == &ipv6_or_ap);
+  tt_assert(fascist_firewall_choose_address(&n_ipv4_ap, &n_ipv6_ap, 0,
+                                                 FIREWALL_OR_CONNECTION, 0)
+            == NULL);
+
+  tt_assert(fascist_firewall_choose_address(&ipv4_dir_ap, &n_ipv6_ap, 0,
+                                                 FIREWALL_DIR_CONNECTION, 0)
+            == &ipv4_dir_ap);
+  tt_assert(fascist_firewall_choose_address(&n_ipv4_ap, &ipv6_dir_ap, 0,
+                                                 FIREWALL_DIR_CONNECTION, 0)
+            == &ipv6_dir_ap);
+  tt_assert(fascist_firewall_choose_address(&n_ipv4_ap, &n_ipv6_ap, 0,
+                                                 FIREWALL_DIR_CONNECTION, 0)
+            == NULL);
+
+ done:
+  UNMOCK(get_options);
+}
+
+#undef TEST_IPV4_ADDR_STR
+#undef TEST_IPV6_ADDR_STR
+#undef TEST_IPV4_OR_PORT
+#undef TEST_IPV4_DIR_PORT
+#undef TEST_IPV6_OR_PORT
+#undef TEST_IPV6_DIR_PORT
+
 struct testcase_t policy_tests[] = {
   { "router_dump_exit_policy_to_string", test_dump_exit_policy_to_string, 0,
     NULL, NULL },
@@ -1137,6 +1580,10 @@ struct testcase_t policy_tests[] = {
   { "reject_interface_address", test_policies_reject_interface_address, 0,
     NULL, NULL },
   { "reject_port_address", test_policies_reject_port_address, 0, NULL, NULL },
+  { "fascist_firewall_allows_address",
+    test_policies_fascist_firewall_allows_address, 0, NULL, NULL },
+  { "fascist_firewall_choose_address",
+    test_policies_fascist_firewall_choose_address, 0, NULL, NULL },
   END_OF_TESTCASES
 };