Add necessary code to parse and handle required/recommended protocols

src/or/networkstatus.c

@@ -28,6 +28,7 @@
 #include "microdesc.h"
 #include "networkstatus.h"
 #include "nodelist.h"
+#include "protover.h"
 #include "relay.h"
 #include "router.h"
 #include "routerlist.h"
@@ -275,6 +276,11 @@ networkstatus_vote_free(networkstatus_t *ns)
 
   tor_free(ns->client_versions);
   tor_free(ns->server_versions);
+  tor_free(ns->recommended_client_protocols);
+  tor_free(ns->recommended_relay_protocols);
+  tor_free(ns->required_client_protocols);
+  tor_free(ns->required_relay_protocols);
+
   if (ns->known_flags) {
     SMARTLIST_FOREACH(ns->known_flags, char *, c, tor_free(c));
     smartlist_free(ns->known_flags);
@@ -2364,6 +2370,56 @@ getinfo_helper_networkstatus(control_connection_t *conn,
   return 0;
 }
 
+/** Check whether the networkstatus <b>ns</b> lists any protocol
+ * versions as "required" or "recommended" that we do not support.  If
+ * so, set *<b>warning_out</b> to a newly allocated string describing
+ * the problem.
+ *
+ * Return 1 if we should exit, 0 if we should not. */
+int
+networkstatus_check_required_protocols(const networkstatus_t *ns,
+                                       int client_mode,
+                                       char **warning_out)
+{
+  const char *func = client_mode ? "client" : "relay";
+  const char *required, *recommended;
+  char *missing = NULL;
+
+  tor_assert(warning_out);
+
+  if (client_mode) {
+    required = ns->required_client_protocols;
+    recommended = ns->recommended_client_protocols;
+  } else {
+    required = ns->required_relay_protocols;
+    recommended = ns->recommended_relay_protocols;
+  }
+
+  if (!protover_all_supported(required, &missing)) {
+    tor_asprintf(warning_out, "At least one protocol listed as required in "
+                 "the consensus is not supported by this version of Tor. "
+                 "You should upgrade. This version of Tor will not work as a "
+                 "%s on the Tor network. The missing protocols are: %s",
+                 func, missing);
+    tor_free(missing);
+    return 1;
+  }
+
+  if (! protover_all_supported(recommended, &missing)) {
+    tor_asprintf(warning_out, "At least one protocol listed as recommended in "
+                 "the consensus is not supported by this version of Tor. "
+                 "You should upgrade. This version of Tor will eventually "
+                 "stop working as a %s on the Tor network. The missing "
+                 "protocols are: %s",
+                 func, missing);
+    tor_free(missing);
+  }
+
+  tor_assert_nonfatal(missing == NULL);
+
+  return 0;
+}
+
 /** Free all storage held locally in this module. */
 void
 networkstatus_free_all(void)

src/or/networkstatus.h

@@ -122,6 +122,9 @@ void document_signature_free(document_signature_t *sig);
 document_signature_t *document_signature_dup(const document_signature_t *sig);
 void networkstatus_free_all(void);
 int networkstatus_get_weight_scale_param(networkstatus_t *ns);
+int networkstatus_check_required_protocols(const networkstatus_t *ns,
+                                           int client_mode,
+                                           char **warning_out);
 
 #ifdef NETWORKSTATUS_PRIVATE
 STATIC void vote_routerstatus_free(vote_routerstatus_t *rs);

src/or/or.h

@@ -2525,6 +2525,16 @@ typedef struct networkstatus_t {
    * voter has no opinion. */
   char *client_versions;
   char *server_versions;
+
+  /** Lists of subprotocol versions which are _recommended_ for relays and
+   * clients, or which are _require_ for relays and clients. Tor shouldn't
+   * make any more network connections if a required protocol is missing.
+   */
+  char *recommended_relay_protocols;
+  char *recommended_client_protocols;
+  char *required_relay_protocols;
+  char *required_client_protocols;
+
   /** List of flags that this vote/consensus applies to routers.  If a flag is
    * not listed here, the voter has no opinion on what its value should be. */
   smartlist_t *known_flags;

src/or/routerparse.c

@@ -75,6 +75,10 @@ typedef enum {
   K_DIR_OPTIONS,
   K_CLIENT_VERSIONS,
   K_SERVER_VERSIONS,
+  K_RECOMMENDED_CLIENT_PROTOCOLS,
+  K_RECOMMENDED_RELAY_PROTOCOLS,
+  K_REQUIRED_CLIENT_PROTOCOLS,
+  K_REQUIRED_RELAY_PROTOCOLS,
   K_OR_ADDRESS,
   K_ID,
   K_P,
@@ -461,6 +465,14 @@ static token_rule_t networkstatus_token_table[] = {
   T01("shared-rand-previous-value", K_PREVIOUS_SRV,EQ(2),       NO_OBJ ),
   T01("shared-rand-current-value",  K_CURRENT_SRV, EQ(2),       NO_OBJ ),
   T0N("package",               K_PACKAGE,          CONCAT_ARGS, NO_OBJ ),
+  T01("recommended-client-protocols", K_RECOMMENDED_CLIENT_PROTOCOLS,
+      CONCAT_ARGS, NO_OBJ ),
+  T01("recommended-relay-protocols", K_RECOMMENDED_RELAY_PROTOCOLS,
+      CONCAT_ARGS, NO_OBJ ),
+  T01("required-client-protocols",    K_REQUIRED_CLIENT_PROTOCOLS,
+      CONCAT_ARGS, NO_OBJ ),
+  T01("required-relay-protocols",    K_REQUIRED_RELAY_PROTOCOLS,
+      CONCAT_ARGS, NO_OBJ ),
 
   CERTIFICATE_MEMBERS
 
@@ -502,6 +514,15 @@ static token_rule_t networkstatus_consensus_token_table[] = {
   T01("shared-rand-previous-value", K_PREVIOUS_SRV, EQ(2),   NO_OBJ ),
   T01("shared-rand-current-value",  K_CURRENT_SRV,  EQ(2),   NO_OBJ ),
 
+  T01("recommended-client-protocols", K_RECOMMENDED_CLIENT_PROTOCOLS,
+      CONCAT_ARGS, NO_OBJ ),
+  T01("recommended-relay-protocols", K_RECOMMENDED_RELAY_PROTOCOLS,
+      CONCAT_ARGS, NO_OBJ ),
+  T01("required-client-protocols",    K_REQUIRED_CLIENT_PROTOCOLS,
+      CONCAT_ARGS, NO_OBJ ),
+  T01("required-relay-protocols",    K_REQUIRED_RELAY_PROTOCOLS,
+      CONCAT_ARGS, NO_OBJ ),
+
   END_OF_TABLE
 };
 
@@ -3651,6 +3672,15 @@ networkstatus_parse_vote_from_string(const char *s, const char **eos_out,
     }
   }
 
+  if ((tok = find_opt_by_keyword(tokens, K_RECOMMENDED_CLIENT_PROTOCOLS)))
+    ns->recommended_client_protocols = tor_strdup(tok->args[0]);
+  if ((tok = find_opt_by_keyword(tokens, K_RECOMMENDED_RELAY_PROTOCOLS)))
+    ns->recommended_relay_protocols = tor_strdup(tok->args[0]);
+  if ((tok = find_opt_by_keyword(tokens, K_REQUIRED_CLIENT_PROTOCOLS)))
+    ns->required_client_protocols = tor_strdup(tok->args[0]);
+  if ((tok = find_opt_by_keyword(tokens, K_REQUIRED_RELAY_PROTOCOLS)))
+    ns->required_relay_protocols = tor_strdup(tok->args[0]);
+
   tok = find_by_keyword(tokens, K_VALID_AFTER);
   if (parse_iso_time(tok->args[0], &ns->valid_after))
     goto err;