From: Nick Mathewson <nickm@torproject.org>
Date: Thu, 17 Apr 2025 13:39:06 +0000 (-0400)
Subject: prop359: Introduce an enum for cell format.
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3c2364790c5a1cf836c15227a9f28b948918d8d3;p=thirdparty%2Ftor.git

prop359: Introduce an enum for cell format.

(Using u8 everywhere makes me nervous.)
---

diff --git a/src/core/or/or.h b/src/core/or/or.h
index 9c6f690a71..88954be32c 100644
--- a/src/core/or/or.h
+++ b/src/core/or/or.h
@@ -472,6 +472,14 @@ typedef enum {
 /** Maximum length of a header on a variable-length cell. */
 #define VAR_CELL_MAX_HEADER_SIZE 7
 
+/** Which format should we use for relay cells? */
+typedef enum relay_cell_fmt_t {
+  /** Our original format, with 2 byte recognized field and a 4-byte digest */
+  RELAY_CELL_FORMAT_V0,
+  /** New format introduced for CGO, with 16 byte tag. */
+  RELAY_CELL_FORMAT_V1,
+} relay_cell_fmt_t;
+
 static int get_cell_network_size(int wide_circ_ids);
 static inline int get_cell_network_size(int wide_circ_ids)
 {
diff --git a/src/core/or/relay_msg_st.h b/src/core/or/relay_msg_st.h
index 4cdaa75d6d..75292b7f89 100644
--- a/src/core/or/relay_msg_st.h
+++ b/src/core/or/relay_msg_st.h
@@ -20,10 +20,10 @@
  * This CAN NOT be made opaque so to avoid heap allocation in the fast path. */
 typedef struct relay_msg_t {
   /* Relay cell protocol version of this message. */
-  uint8_t relay_cell_proto;
+  relay_cell_fmt_t relay_cell_proto;
   /* Relay command of a message. */
   uint8_t command;
-  /* Length of payload. */
+  /* Length of the message body. */
   uint16_t length;
   /* Optional routing header: stream ID of a message or 0. */
   streamid_t stream_id;