protover: Add node functions for IPv6 extend support

Part of 33226.

2 files changed, 56 insertions, 1 deletions

diff --git a/src/feature/nodelist/nodelist.c b/src/feature/nodelist/nodelist.c
index 6a8e1723de..a553390628 100644
--- a/src/feature/nodelist/nodelist.c
+++ b/src/feature/nodelist/nodelist.c
@@ -1133,7 +1133,7 @@ node_ed25519_id_matches(const node_t *node, const ed25519_public_key_t *id)
 /** Dummy object that should be unreturnable.  Used to ensure that
  * node_get_protover_summary_flags() always returns non-NULL. */
 static const protover_summary_flags_t zero_protover_flags = {
-  0,0,0,0,0,0,0,0,0
+  0,0,0,0,0,0,0,0,0,0,0,0
 };
 
 /** Return the protover_summary_flags for a given node. */
@@ -1219,6 +1219,56 @@ node_supports_establish_intro_dos_extension(const node_t *node)
                            supports_establish_intro_dos_extension;
 }
 
+/** Return true iff <b>node</b> can initiate IPv6 extends (Relay=3).
+ *
+ * This check should only be performed by client path selection code.
+ *
+ * Extending relays should check their own IPv6 support using
+ * router_can_extend_over_ipv6(). Like other extends, they should not verify
+ * the link specifiers in the extend cell against the consensus, because it
+ * may be out of date. */
+bool
+node_supports_initiating_ipv6_extends(const node_t *node)
+{
+  tor_assert(node);
+
+  /* Relays can't initiate an IPv6 extend, unless they have an IPv6 ORPort. */
+  if (!node_has_ipv6_orport(node)) {
+    return 0;
+  }
+
+  /* Initiating relays also need to support the relevant protocol version. */
+  return
+    node_get_protover_summary_flags(node)->supports_initiating_ipv6_extends;
+}
+
+/** Return true iff <b>node</b> can accept IPv6 extends (Relay=2 or Relay=3)
+ * from other relays. If <b>need_canonical_ipv6_conn</b> is true, also check
+ * if the relay supports canonical IPv6 connections (Relay=3 only).
+ *
+ * This check should only be performed by client path selection code.
+ */
+bool
+node_supports_accepting_ipv6_extends(const node_t *node,
+                                            bool need_canonical_ipv6_conn)
+{
+  tor_assert(node);
+
+  /* Relays can't accept an IPv6 extend, unless they have an IPv6 ORPort. */
+  if (!node_has_ipv6_orport(node)) {
+    return 0;
+  }
+
+  /* Accepting relays also need to support the relevant protocol version. */
+  if (need_canonical_ipv6_conn) {
+    return
+      node_get_protover_summary_flags(node)->supports_canonical_ipv6_conns;
+  } else {
+    return
+      node_get_protover_summary_flags(node)->supports_accepting_ipv6_extends;
+  }
+}
+
 /** Return the RSA ID key's SHA1 digest for the provided node. */
 const uint8_t *
 node_get_rsa_id_digest(const node_t *node)
diff --git a/src/feature/nodelist/nodelist.h b/src/feature/nodelist/nodelist.h
index 57ab2d5913..991cec319b 100644
--- a/src/feature/nodelist/nodelist.h
+++ b/src/feature/nodelist/nodelist.h
@@ -81,6 +81,11 @@ int node_supports_v3_hsdir(const node_t *node);
 int node_supports_ed25519_hs_intro(const node_t *node);
 int node_supports_v3_rendezvous_point(const node_t *node);
 int node_supports_establish_intro_dos_extension(const node_t *node);
+bool node_supports_initiating_ipv6_extends(const node_t *node);
+bool node_supports_accepting_ipv6_extends(
+                                             const node_t *node,
+                                             bool need_canonical_ipv6_conn);
+
 const uint8_t *node_get_rsa_id_digest(const node_t *node);
 MOCK_DECL(smartlist_t *,node_get_link_specifier_smartlist,(const node_t *node,
                                                            bool direct_conn));