prop224: Add client code to handle fetched HS descriptors.

This code handles received HS descriptors by storing them in the
client-side HS cache.

Signed-off-by: David Goulet <dgoulet@torproject.org>

src/or/directory.c

@@ -2538,6 +2538,9 @@ connection_dir_client_reached_eof(dir_connection_t *conn)
     case DIR_PURPOSE_UPLOAD_HSDESC:
       rv = handle_response_upload_hsdesc(conn, &args);
       break;
+    case DIR_PURPOSE_FETCH_HSDESC:
+      rv = handle_response_fetch_hsdesc_v3(conn, &args);
+      break;
     default:
       tor_assert_nonfatal_unreached();
       rv = -1;
@@ -3082,6 +3085,58 @@ handle_response_upload_signatures(dir_connection_t *conn,
   return 0;
 }
 
+/**
+ * Handler function: processes a response to a request for a v3 hidden service
+ * descriptor.
+ **/
+STATIC int
+handle_response_fetch_hsdesc_v3(dir_connection_t *conn,
+                                const response_handler_args_t *args)
+{
+  const int status_code = args->status_code;
+  const char *reason = args->reason;
+  const char *body = args->body;
+  const size_t body_len = args->body_len;
+
+  tor_assert(conn->hs_ident);
+
+  log_info(LD_REND,"Received v3 hsdesc (body size %d, status %d (%s))",
+           (int)body_len, status_code, escaped(reason));
+
+  switch (status_code) {
+  case 200:
+    /* We got something: Try storing it in the cache. */
+    if (hs_cache_store_as_client(body, &conn->hs_ident->identity_pk) < 0) {
+      log_warn(LD_REND, "Failed to store hidden service descriptor");
+    } else {
+      log_info(LD_REND, "Stored hidden service descriptor successfully.");
+    }
+    break;
+  case 404:
+    /* Not there. We'll retry when connection_about_to_close_connection()
+     * tries to clean this conn up. */
+    log_info(LD_REND, "Fetching hidden service v3 descriptor not found: "
+                      "Retrying at another directory.");
+    /* TODO: Inform the control port */
+    break;
+  case 400:
+    log_warn(LD_REND, "Fetching v3 hidden service descriptor failed: "
+                      "http status 400 (%s). Dirserver didn't like our "
+                      "query? Retrying at another directory.",
+             escaped(reason));
+    break;
+  default:
+    log_warn(LD_REND, "Fetching v3 hidden service descriptor failed: "
+             "http status %d (%s) response unexpected from HSDir server "
+             "'%s:%d'. Retrying at another directory.",
+             status_code, escaped(reason), TO_CONN(conn)->address,
+             TO_CONN(conn)->port);
+    break;
+  }
+
+  return 0;
+}
+
 /**
  * Handler function: processes a response to a request for a v2 hidden service
  * descriptor.

src/or/directory.h

@@ -176,6 +176,10 @@ STATIC char *accept_encoding_header(void);
 STATIC int allowed_anonymous_connection_compression_method(compress_method_t);
 STATIC void warn_disallowed_anonymous_compression_method(compress_method_t);
 
+typedef struct response_handler_args_t response_handler_args_t;
+STATIC int handle_response_fetch_hsdesc_v3(dir_connection_t *conn,
+                                          const response_handler_args_t *args);
+
 #endif
 
 #ifdef TOR_UNIT_TESTS