From f59990f24ddf3e5c7cdeb82c9e8cf16c7dcce56b Mon Sep 17 00:00:00 2001
From: George Kadianakis <desnacked@riseup.net>
Date: Thu, 25 Aug 2016 11:04:59 -0400
Subject: [PATCH] prop224: Directory support for v3 descriptor fetch

Signed-off-by: David Goulet <dgoulet@torproject.org>
Signed-off-by: George Kadianakis <desnacked@riseup.net>
---
 src/or/directory.c | 51 ++++++++++++++++++++++++++++++++++++++++++----
 src/or/directory.h | 10 ++++++++-
 2 files changed, 56 insertions(+), 5 deletions(-)

diff --git a/src/or/directory.c b/src/or/directory.c
index 8abdc454e8..f72bc556fe 100644
--- a/src/or/directory.c
+++ b/src/or/directory.c
@@ -3,6 +3,8 @@
  * Copyright (c) 2007-2016, The Tor Project, Inc. */
 /* See LICENSE for licensing information */
 
+#define DIRECTORY_PRIVATE
+
 #include "or.h"
 #include "backtrace.h"
 #include "buffers.h"
@@ -2770,8 +2772,8 @@ static int handle_get_descriptor(dir_connection_t *conn,
                                 const get_handler_args_t *args);
 static int handle_get_keys(dir_connection_t *conn,
                                 const get_handler_args_t *args);
-static int handle_get_rendezvous2(dir_connection_t *conn,
-                                const get_handler_args_t *args);
+static int handle_get_hs_descriptor_v2(dir_connection_t *conn,
+                                       const get_handler_args_t *args);
 static int handle_get_robots(dir_connection_t *conn,
                                 const get_handler_args_t *args);
 static int handle_get_networkstatus_bridges(dir_connection_t *conn,
@@ -2787,7 +2789,8 @@ static const url_table_ent_t url_table[] = {
   { "/tor/server/", 1, handle_get_descriptor },
   { "/tor/extra/", 1, handle_get_descriptor },
   { "/tor/keys/", 1, handle_get_keys },
-  { "/tor/rendezvous2/", 1, handle_get_rendezvous2 },
+  { "/tor/rendezvous2/", 1, handle_get_hs_descriptor_v2 },
+  { "/tor/hs/3/", 1, handle_get_hs_descriptor_v3 },
   { "/tor/robots.txt", 0, handle_get_robots },
   { "/tor/networkstatus-bridges", 0, handle_get_networkstatus_bridges },
   { NULL, 0, NULL },
@@ -3355,7 +3358,8 @@ handle_get_keys(dir_connection_t *conn, const get_handler_args_t *args)
 /** Helper function for GET /tor/rendezvous2/
  */
 static int
-handle_get_rendezvous2(dir_connection_t *conn, const get_handler_args_t *args)
+handle_get_hs_descriptor_v2(dir_connection_t *conn,
+                            const get_handler_args_t *args)
 {
   const char *url = args->url;
   if (connection_dir_is_encrypted(conn)) {
@@ -3389,6 +3393,45 @@ handle_get_rendezvous2(dir_connection_t *conn, const get_handler_args_t *args)
   return 0;
 }
 
+/** Helper function for GET /tor/hs/3/<z>. Only for version 3.
+ */
+STATIC int
+handle_get_hs_descriptor_v3(dir_connection_t *conn,
+                            const get_handler_args_t *args)
+{
+  int retval;
+  char *desc_str = NULL;
+  const char *pubkey_str = NULL;
+  const char *url = args->url;
+
+  /* Reject unencrypted dir connections */
+  if (!connection_dir_is_encrypted(conn)) {
+    write_http_status_line(conn, 404, "Not found");
+    goto done;
+  }
+
+  /* After the path prefix follows the base64 encoded blinded pubkey which we
+   * use to get the descriptor from the cache. Skip the prefix and get the
+   * pubkey. */
+  tor_assert(!strcmpstart(url, "/tor/hs/3/"));
+  pubkey_str = url + strlen("/tor/hs/3/");
+  retval = hs_cache_lookup_as_dir(HS_VERSION_THREE,
+                                  pubkey_str, &desc_str);
+  if (retval < 0) {
+    write_http_status_line(conn, 404, "Not found");
+    goto done;
+  }
+
+  /* Found requested descriptor! Pass it to this nice client. */
+  write_http_response_header(conn, strlen(desc_str), 0, 0);
+  connection_write_to_buf(desc_str, strlen(desc_str), TO_CONN(conn));
+
+ done:
+  tor_free(desc_str);
+
+  return 0;
+}
+
 /** Helper function for GET /tor/networkstatus-bridges
  */
 static int
diff --git a/src/or/directory.h b/src/or/directory.h
index a6c33d7f39..2fe42f2de6 100644
--- a/src/or/directory.h
+++ b/src/or/directory.h
@@ -134,8 +134,16 @@ time_t download_status_get_next_attempt_at(const download_status_t *dls);
 
 int purpose_needs_anonymity(uint8_t dir_purpose, uint8_t router_purpose);
 
+#ifdef DIRECTORY_PRIVATE
+
+struct get_handler_args_t;
+STATIC int handle_get_hs_descriptor_v3(dir_connection_t *conn,
+                                       const struct get_handler_args_t *args);
+
+#endif
+
 #ifdef TOR_UNIT_TESTS
-/* Used only by directory.c and test_dir.c */
+/* Used only by test_dir.c */
 
 STATIC int parse_http_url(const char *headers, char **url);
 STATIC dirinfo_type_t dir_fetch_type(int dir_purpose, int router_purpose,