Merge branch 'ipv6-only-client_squashed'

6 files changed, 80 insertions, 44 deletions

diff --git a/changes/bug20996 b/changes/bug20996
new file mode 100644
index 0000000000..b2be805b0a
--- /dev/null
+++ b/changes/bug20996
@@ -0,0 +1,9 @@
+  o Minor bugfixes (IPv6):
+    - Make IP6-using clients try harder to find an IPv6 directory server.
+      Fixes bug 20999; bugfix on 77a9de0 from 17840 in 0.2.8.2-alpha.
+    - When IPv6 addresses have not been downloaded, use hard-coded address
+      info for authorities, fallbacks, and configured bridges.
+      (When IPv6-only clients receive a microdesc consensus, it has no IPv6
+      addresses, so they can't use it until microdescs are downloaded.)
+      This allows IPv6-only clients to use microdescriptors.
+      Fixes bug 20996; bugfix on b167e82 from 19608 in 0.2.8.5-alpha.
diff --git a/src/or/config.c b/src/or/config.c
index d4177878e7..b8ca14e85b 100644
--- a/src/or/config.c
+++ b/src/or/config.c
@@ -3361,23 +3361,6 @@ options_validate(or_options_t *old_options, or_options_t *options,
            "of the Internet, so they must not set Reachable*Addresses "
            "or FascistFirewall or FirewallPorts or ClientUseIPv4 0.");
 
-  /* We check if Reachable*Addresses blocks all addresses in
-   * parse_reachable_addresses(). */
-
-#define WARN_PLEASE_USE_IPV6_LOG_MSG \
-        "ClientPreferIPv6%sPort 1 is ignored unless tor is using IPv6. " \
-        "Please set ClientUseIPv6 1, ClientUseIPv4 0, or configure bridges."
-
-  if (!fascist_firewall_use_ipv6(options)
-      && options->ClientPreferIPv6ORPort == 1)
-    log_warn(LD_CONFIG, WARN_PLEASE_USE_IPV6_LOG_MSG, "OR");
-
-  if (!fascist_firewall_use_ipv6(options)
-      && options->ClientPreferIPv6DirPort == 1)
-    log_warn(LD_CONFIG, WARN_PLEASE_USE_IPV6_LOG_MSG, "Dir");
-
-#undef WARN_PLEASE_USE_IPV6_LOG_MSG
-
   if (options->UseBridges &&
       server_mode(options))
     REJECT("Servers must be able to freely connect to the rest "
diff --git a/src/or/nodelist.c b/src/or/nodelist.c
index 2bcedbfb0c..804af297ba 100644
--- a/src/or/nodelist.c
+++ b/src/or/nodelist.c
@@ -1126,6 +1126,9 @@ node_get_prim_orport(const node_t *node, tor_addr_port_t *ap_out)
   node_assert_ok(node);
   tor_assert(ap_out);
 
+  /* Check ri first, because rewrite_node_address_for_bridge() updates
+   * node->ri with the configured bridge address. */
+
   RETURN_IPV4_AP(node->ri, or_port, ap_out);
   RETURN_IPV4_AP(node->rs, or_port, ap_out);
   /* Microdescriptors only have an IPv6 address */
@@ -1156,9 +1159,11 @@ node_get_pref_ipv6_orport(const node_t *node, tor_addr_port_t *ap_out)
   node_assert_ok(node);
   tor_assert(ap_out);
 
-  /* Prefer routerstatus over microdesc for consistency with the
-   * fascist_firewall_* functions. Also check if the address or port are valid,
-   * and try another alternative if they are not. */
+  /* Check ri first, because rewrite_node_address_for_bridge() updates
+   * node->ri with the configured bridge address.
+   * Prefer rs over md for consistency with the fascist_firewall_* functions.
+   * Check if the address or port are valid, and try another alternative
+   * if they are not. */
 
   if (node->ri && tor_addr_port_is_valid(&node->ri->ipv6_addr,
                                          node->ri->ipv6_orport, 0)) {
@@ -1218,6 +1223,9 @@ node_get_prim_dirport(const node_t *node, tor_addr_port_t *ap_out)
   node_assert_ok(node);
   tor_assert(ap_out);
 
+  /* Check ri first, because rewrite_node_address_for_bridge() updates
+   * node->ri with the configured bridge address. */
+
   RETURN_IPV4_AP(node->ri, dir_port, ap_out);
   RETURN_IPV4_AP(node->rs, dir_port, ap_out);
   /* Microdescriptors only have an IPv6 address */
@@ -1250,8 +1258,11 @@ node_get_pref_ipv6_dirport(const node_t *node, tor_addr_port_t *ap_out)
   node_assert_ok(node);
   tor_assert(ap_out);
 
-  /* Check if the address or port are valid, and try another alternative if
-   * they are not. Note that microdescriptors have no dir_port. */
+  /* Check ri first, because rewrite_node_address_for_bridge() updates
+   * node->ri with the configured bridge address.
+   * Prefer rs over md for consistency with the fascist_firewall_* functions.
+   * Check if the address or port are valid, and try another alternative
+   * if they are not. */
 
   /* Assume IPv4 and IPv6 dirports are the same */
   if (node->ri && tor_addr_port_is_valid(&node->ri->ipv6_addr,
diff --git a/src/or/policies.c b/src/or/policies.c
index f4c0cddbcc..84600f7ef8 100644
--- a/src/or/policies.c
+++ b/src/or/policies.c
@@ -20,6 +20,7 @@
 #include "or.h"
 #include "config.h"
 #include "dirserv.h"
+#include "microdesc.h"
 #include "networkstatus.h"
 #include "nodelist.h"
 #include "policies.h"
@@ -297,8 +298,8 @@ parse_reachable_addresses(void)
     } else if (fascist_firewall_use_ipv6(options)
        && (policy_is_reject_star(reachable_or_addr_policy, AF_INET6, 0)
          || policy_is_reject_star(reachable_dir_addr_policy, AF_INET6, 0))) {
-          log_warn(LD_CONFIG, "You have configured tor to use IPv6 "
-                   "(ClientUseIPv6 1 or UseBridges 1), but "
+          log_warn(LD_CONFIG, "You have configured tor to use or prefer IPv6 "
+                   "(or UseBridges 1), but "
                    "ReachableAddresses, ReachableORAddresses, or "
                    "ReachableDirAddresses reject all IPv6 addresses. "
                    "Tor will not connect using IPv6.");
@@ -316,10 +317,8 @@ firewall_is_fascist_impl(void)
   const or_options_t *options = get_options();
   /* Assume every non-bridge relay has an IPv4 address.
    * Clients which use bridges may only know the IPv6 address of their
-   * bridge. */
-  return (options->ClientUseIPv4 == 0
-          || (!fascist_firewall_use_ipv6(options)
-              && options->UseBridges == 1));
+   * bridge, but they will connect regardless of the ClientUseIPv6 setting. */
+  return options->ClientUseIPv4 == 0;
 }
 
 /** Return true iff the firewall options, including ClientUseIPv4 0 and
@@ -426,6 +425,9 @@ fascist_firewall_allows_address(const tor_addr_t *addr,
 }
 
 /** Is this client configured to use IPv6?
+ * Returns true if the client might use IPv6 for some of its connections
+ * (including dual-stack and IPv6-only clients), and false if it will never
+ * use IPv6 for any connections.
  * Use node_ipv6_or/dir_preferred() when checking a specific node and OR/Dir
  * port: it supports bridge client per-node IPv6 preferences.
  */
@@ -433,9 +435,11 @@ int
 fascist_firewall_use_ipv6(const or_options_t *options)
 {
   /* Clients use IPv6 if it's set, or they use bridges, or they don't use
-   * IPv4 */
-  return (options->ClientUseIPv6 == 1 || options->UseBridges == 1
-          || options->ClientUseIPv4 == 0);
+   * IPv4, or they prefer it.
+   * ClientPreferIPv6DirPort is deprecated, but check it anyway. */
+  return (options->ClientUseIPv6 == 1 || options->ClientUseIPv4 == 0 ||
+          options->ClientPreferIPv6ORPort == 1 ||
+          options->ClientPreferIPv6DirPort == 1 || options->UseBridges == 1);
 }
 
 /** Do we prefer to connect to IPv6, ignoring ClientPreferIPv6ORPort and
@@ -888,6 +892,33 @@ fascist_firewall_choose_address_ipv4h(uint32_t ipv4h_addr,
                                               pref_ipv6, ap);
 }
 
+/* The microdescriptor consensus has no IPv6 addresses in rs: they are in
+ * the microdescriptors. This means we can't rely on the node's IPv6 address
+ * until its microdescriptor is available (when using microdescs).
+ * But for bridges, rewrite_node_address_for_bridge() updates node->ri with
+ * the configured address, so we can trust bridge addresses.
+ * (Bridges could gain an IPv6 address if their microdescriptor arrives, but
+ * this will never be their preferred address: that is in the config.)
+ * Returns true if the node needs a microdescriptor for its IPv6 address, and
+ * false if the addresses in the node are already up-to-date.
+ */
+static int
+node_awaiting_ipv6(const or_options_t* options, const node_t *node)
+{
+  tor_assert(node);
+
+  /* There's no point waiting for an IPv6 address if we'd never use it */
+  if (!fascist_firewall_use_ipv6(options)) {
+    return 0;
+  }
+
+  /* We are waiting if we_use_microdescriptors_for_circuits() and we have no
+   * md. Bridges have a ri based on their config. They would never use the
+   * address from their md, so there's no need to wait for it. */
+  return (!node->md && we_use_microdescriptors_for_circuits(options) &&
+          !node->ri);
+}
+
 /** Like fascist_firewall_choose_address_base(), but takes <b>rs</b>.
  * Consults the corresponding node, then falls back to rs if node is NULL.
  * This should only happen when there's no valid consensus, and rs doesn't
@@ -904,15 +935,15 @@ fascist_firewall_choose_address_rs(const routerstatus_t *rs,
 
   tor_assert(ap);
 
+  const or_options_t *options = get_options();
   const node_t *node = node_get_by_id(rs->identity_digest);
 
-  if (node) {
+  if (node && !node_awaiting_ipv6(options, node)) {
     return fascist_firewall_choose_address_node(node, fw_connection, pref_only,
                                                 ap);
   } else {
     /* There's no node-specific IPv6 preference, so use the generic IPv6
      * preference instead. */
-    const or_options_t *options = get_options();
     int pref_ipv6 = (fw_connection == FIREWALL_OR_CONNECTION
                      ? fascist_firewall_prefer_ipv6_orport(options)
                      : fascist_firewall_prefer_ipv6_dirport(options));
@@ -946,6 +977,18 @@ fascist_firewall_choose_address_node(const node_t *node,
 
   node_assert_ok(node);
 
+  /* Calling fascist_firewall_choose_address_node() when the node is missing
+   * IPv6 information breaks IPv6-only clients.
+   * If the node is a hard-coded fallback directory or authority, call
+   * fascist_firewall_choose_address_rs() on the fake (hard-coded) routerstatus
+   * for the node.
+   * If it is not hard-coded, check that the node has a microdescriptor, full
+   * descriptor (routerinfo), or is one of our configured bridges before
+   * calling this function. */
+  if (BUG(node_awaiting_ipv6(get_options(), node))) {
+    return 0;
+  }
+
   const int pref_ipv6_node = (fw_connection == FIREWALL_OR_CONNECTION
                               ? node_ipv6_or_preferred(node)
                               : node_ipv6_dir_preferred(node));
diff --git a/src/or/routerlist.c b/src/or/routerlist.c
index 78e7d02ebe..e6ccdddbef 100644
--- a/src/or/routerlist.c
+++ b/src/or/routerlist.c
@@ -949,7 +949,7 @@ authority_certs_fetch_resource_impl(const char *resource,
 
   /* If we've just downloaded a consensus from a bridge, re-use that
    * bridge */
-  if (options->UseBridges && node && !get_via_tor) {
+  if (options->UseBridges && node && node->ri && !get_via_tor) {
     /* clients always make OR connections to bridges */
     tor_addr_port_t or_ap;
     /* we are willing to use a non-preferred address if we need to */
diff --git a/src/test/test_options.c b/src/test/test_options.c
index 29ec1e9824..ce5e1ed62c 100644
--- a/src/test/test_options.c
+++ b/src/test/test_options.c
@@ -1797,14 +1797,6 @@ test_options_validate__reachable_addresses(void *ignored)
 
   /* Test IPv4-only clients setting IPv6 preferences */
 
-#define WARN_PLEASE_USE_IPV6_OR_LOG_MSG \
-        "ClientPreferIPv6ORPort 1 is ignored unless tor is using IPv6. " \
-        "Please set ClientUseIPv6 1, ClientUseIPv4 0, or configure bridges.\n"
-
-#define WARN_PLEASE_USE_IPV6_DIR_LOG_MSG \
-        "ClientPreferIPv6DirPort 1 is ignored unless tor is using IPv6. " \
-        "Please set ClientUseIPv6 1, ClientUseIPv4 0, or configure bridges.\n"
-
   free_options_test_data(tdata);
   tdata = get_options_test_data(TEST_OPTIONS_DEFAULT_VALUES
                                 "ClientUseIPv4 1\n"
@@ -1814,7 +1806,6 @@ test_options_validate__reachable_addresses(void *ignored)
 
   ret = options_validate(tdata->old_opt, tdata->opt, tdata->def_opt, 0, &msg);
   tt_int_op(ret, OP_EQ, 0);
-  expect_log_msg(WARN_PLEASE_USE_IPV6_OR_LOG_MSG);
   tor_free(msg);
 
   free_options_test_data(tdata);
@@ -1826,7 +1817,6 @@ test_options_validate__reachable_addresses(void *ignored)
 
   ret = options_validate(tdata->old_opt, tdata->opt, tdata->def_opt, 0, &msg);
   tt_int_op(ret, OP_EQ, 0);
-  expect_log_msg(WARN_PLEASE_USE_IPV6_DIR_LOG_MSG);
   tor_free(msg);
 
   /* Now test an IPv4/IPv6 client setting IPv6 preferences */