hs-v3: Implement HS_DESC REQUESTED event

This changes the control_event_hs_descriptor_requested() call to add the hsdir
index optional value. v2 passes NULL all the time.

This commit creates hs_control.{c|h} that contains wrappers for the HS
subsystem to interact with the control port subsystem.

The descriptor REQUESTED event is implemented following proposal 284 extension
for v3.

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

1 files changed, 52 insertions, 0 deletions

diff --git a/src/or/hs_control.c b/src/or/hs_control.c
new file mode 100644
index 0000000000..0bcb41dccf
--- /dev/null
+++ b/src/or/hs_control.c
@@ -0,0 +1,52 @@
+/* Copyright (c) 2017, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file hs_control.c
+ * \brief Contains control port event related code.
+ **/
+
+#include "or.h"
+#include "control.h"
+#include "hs_common.h"
+#include "hs_control.h"
+#include "nodelist.h"
+
+/* Send on the control port the "HS_DESC REQUESTED [...]" event.
+ *
+ * The onion_pk is the onion service public key, base64_blinded_pk is the
+ * base64 encoded blinded key for the service and hsdir_rs is the routerstatus
+ * object of the HSDir that this request is for. */
+void
+hs_control_desc_event_requested(const ed25519_public_key_t *onion_pk,
+                                const char *base64_blinded_pk,
+                                const routerstatus_t *hsdir_rs)
+{
+  char onion_address[HS_SERVICE_ADDR_LEN_BASE32 + 1];
+  const uint8_t *hsdir_index;
+  const node_t *hsdir_node;
+
+  tor_assert(onion_pk);
+  tor_assert(base64_blinded_pk);
+  tor_assert(hsdir_rs);
+
+  hs_build_address(onion_pk, HS_VERSION_THREE, onion_address);
+
+  /* Get the node from the routerstatus object to get the HSDir index used for
+   * this request. We can't have a routerstatus entry without a node and we
+   * can't pick a node without an hsdir_index. */
+  hsdir_node = node_get_by_id(hsdir_rs->identity_digest);
+  tor_assert(hsdir_node);
+  tor_assert(hsdir_node->hsdir_index);
+  /* This is a fetch event. */
+  hsdir_index = hsdir_node->hsdir_index->fetch;
+
+  /* Trigger the event. */
+  control_event_hs_descriptor_requested(onion_address, REND_NO_AUTH,
+                                        hsdir_rs->identity_digest,
+                                        base64_blinded_pk,
+                                        hex_str((const char *) hsdir_index,
+                                                DIGEST256_LEN));
+  memwipe(onion_address, 0, sizeof(onion_address));
+}
+