Change HiddenServiceExportCircuitID to take a string parameter: the protocol.

This patch changes HiddenServiceExportCircuitID so instead of being a
boolean it takes a string, which is the protocol. Currently only the
'haproxy' protocol is defined.

See: https://bugs.torproject.org/4700

3 files changed, 42 insertions, 7 deletions

diff --git a/src/feature/hs/hs_config.c b/src/feature/hs/hs_config.c
index 16bfe7c544..2378a4d3b2 100644
--- a/src/feature/hs/hs_config.c
+++ b/src/feature/hs/hs_config.c
@@ -145,6 +145,31 @@ helper_parse_uint64(const char *opt, const char *value, uint64_t min,
   return ret;
 }
 
+/** Helper function: Given a configuration option and its value, parse the
+ * value as a hs_circuit_id_protocol_t. On success, ok is set to 1 and ret is
+ * the parse value. On error, ok is set to 0 and the "none"
+ * hs_circuit_id_protocol_t is returned. This function logs on error. */
+static hs_circuit_id_protocol_t
+helper_parse_circuit_id_protocol(const char *key, const char *value, int *ok)
+{
+  tor_assert(value);
+  tor_assert(ok);
+
+  hs_circuit_id_protocol_t ret = HS_CIRCUIT_ID_PROTOCOL_NONE;
+  *ok = 0;
+
+  if (! strcasecmp(value, "haproxy")) {
+    *ok = 1;
+    ret = HS_CIRCUIT_ID_PROTOCOL_HAPROXY;
+  } else {
+    log_warn(LD_CONFIG, "%s must be 'haproxy'.", key);
+    goto err;
+  }
+
+ err:
+  return ret;
+}
+
 /* Return the service version by trying to learn it from the key on disk if
  * any. If nothing is found, the current service configured version is
  * returned. */
@@ -295,8 +320,8 @@ config_service_v3(const config_line_t *line_,
       continue;
     }
     if (!strcasecmp(line->key, "HiddenServiceExportCircuitID")) {
-      config->export_circuit_id =
-        (unsigned int) helper_parse_uint64(line->key, line->value, 0, 1, &ok);
+      config->circuit_id_protocol =
+        helper_parse_circuit_id_protocol(line->key, line->value, &ok);
       if (!ok || export_circuit_id) {
         if (export_circuit_id) {
           dup_opt_seen = line->key;
diff --git a/src/feature/hs/hs_service.c b/src/feature/hs/hs_service.c
index 75d7cb75ed..e87cb990f5 100644
--- a/src/feature/hs/hs_service.c
+++ b/src/feature/hs/hs_service.c
@@ -3764,15 +3764,15 @@ hs_service_set_conn_addr_port(const origin_circuit_t *circ,
 
 /** Does the service with identity pubkey <b>pk</b> export the circuit IDs of
  *  its clients?  */
-bool
+hs_circuit_id_protocol_t
 hs_service_exports_circuit_id(const ed25519_public_key_t *pk)
 {
   hs_service_t *service = find_service(hs_service_map, pk);
   if (!service) {
-    return 0;
+    return HS_CIRCUIT_ID_PROTOCOL_NONE;
   }
 
-  return service->config.export_circuit_id;
+  return service->config.circuit_id_protocol;
 }
 
 /* Add to file_list every filename used by a configured hidden service, and to
diff --git a/src/feature/hs/hs_service.h b/src/feature/hs/hs_service.h
index e541cb28b9..6fb15b9d37 100644
--- a/src/feature/hs/hs_service.h
+++ b/src/feature/hs/hs_service.h
@@ -161,6 +161,15 @@ typedef struct hs_service_authorized_client_t {
   curve25519_public_key_t client_pk;
 } hs_service_authorized_client_t;
 
+/** Which protocol to use for exporting HS client circuit ID. */
+typedef enum {
+  /** Don't expose the circuit id. */
+  HS_CIRCUIT_ID_PROTOCOL_NONE,
+
+  /** Use the HAProxy proxy protocol. */
+  HS_CIRCUIT_ID_PROTOCOL_HAPROXY
+} hs_circuit_id_protocol_t;
+
 /* Service configuration. The following are set from the torrc options either
  * set by the configuration file or by the control port. Nothing else should
  * change those values. */
@@ -212,7 +221,7 @@ typedef struct hs_service_config_t {
   unsigned int is_ephemeral : 1;
 
   /* Does this service export the circuit ID of its clients? */
-  bool export_circuit_id;
+  hs_circuit_id_protocol_t circuit_id_protocol;
 } hs_service_config_t;
 
 /* Service state. */
@@ -319,7 +328,8 @@ void hs_service_upload_desc_to_dir(const char *encoded_desc,
                                    const ed25519_public_key_t *blinded_pk,
                                    const routerstatus_t *hsdir_rs);
 
-bool hs_service_exports_circuit_id(const ed25519_public_key_t *pk);
+hs_circuit_id_protocol_t
+hs_service_exports_circuit_id(const ed25519_public_key_t *pk);
 
 #ifdef HS_SERVICE_PRIVATE