trunnel: Make hs/cell_common.trunnel generic

Move it to extension.trunnel instead so that extension ABI construction
can be used in other parts of tor than just HS cells.

Specifically, we'll use it in the ntorv3 data payload and make a
congestion control parameter extension using that binary structure.

Only rename. No code behavior changes.

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

5 files changed, 40 insertions, 43 deletions

diff --git a/src/feature/hs/hs_cell.c b/src/feature/hs/hs_cell.c
index f84407de9e..116395b3c8 100644
--- a/src/feature/hs/hs_cell.c
+++ b/src/feature/hs/hs_cell.c
@@ -19,7 +19,7 @@
 
 /* Trunnel. */
 #include "trunnel/ed25519_cert.h"
-#include "trunnel/hs/cell_common.h"
+#include "trunnel/extension.h"
 #include "trunnel/hs/cell_establish_intro.h"
 #include "trunnel/hs/cell_introduce1.h"
 #include "trunnel/hs/cell_rendezvous.h"
@@ -379,7 +379,7 @@ introduce1_set_encrypted(trn_cell_introduce1_t *cell,
                          const hs_cell_introduce1_data_t *data)
 {
   trn_cell_introduce_encrypted_t *enc_cell;
-  trn_cell_extension_t *ext;
+  trn_extension_t *ext;
 
   tor_assert(cell);
   tor_assert(data);
@@ -388,9 +388,9 @@ introduce1_set_encrypted(trn_cell_introduce1_t *cell,
   tor_assert(enc_cell);
 
   /* Set extension data. None are used. */
-  ext = trn_cell_extension_new();
+  ext = trn_extension_new();
   tor_assert(ext);
-  trn_cell_extension_set_num(ext, 0);
+  trn_extension_set_num(ext, 0);
   trn_cell_introduce_encrypted_set_extensions(enc_cell, ext);
 
   /* Set the rendezvous cookie. */
@@ -454,20 +454,20 @@ build_establish_intro_dos_param(trn_cell_extension_dos_t *dos_ext,
  * possible if there is a bug.) */
 static int
 build_establish_intro_dos_extension(const hs_service_config_t *service_config,
-                                    trn_cell_extension_t *extensions)
+                                    trn_extension_t *extensions)
 {
   ssize_t ret;
   size_t dos_ext_encoded_len;
   uint8_t *field_array;
-  trn_cell_extension_field_t *field = NULL;
+  trn_extension_field_t *field = NULL;
   trn_cell_extension_dos_t *dos_ext = NULL;
 
   tor_assert(service_config);
   tor_assert(extensions);
 
   /* We are creating a cell extension field of the type DoS. */
-  field = trn_cell_extension_field_new();
-  trn_cell_extension_field_set_field_type(field,
+  field = trn_extension_field_new();
+  trn_extension_field_set_field_type(field,
                                           TRUNNEL_CELL_EXTENSION_TYPE_DOS);
 
   /* Build DoS extension field. We will put in two parameters. */
@@ -490,24 +490,23 @@ build_establish_intro_dos_extension(const hs_service_config_t *service_config,
   }
   dos_ext_encoded_len = ret;
   /* Set length field and the field array size length. */
-  trn_cell_extension_field_set_field_len(field, dos_ext_encoded_len);
-  trn_cell_extension_field_setlen_field(field, dos_ext_encoded_len);
+  trn_extension_field_set_field_len(field, dos_ext_encoded_len);
+  trn_extension_field_setlen_field(field, dos_ext_encoded_len);
   /* Encode the DoS extension into the cell extension field. */
-  field_array = trn_cell_extension_field_getarray_field(field);
+  field_array = trn_extension_field_getarray_field(field);
   ret = trn_cell_extension_dos_encode(field_array,
-                 trn_cell_extension_field_getlen_field(field), dos_ext);
+                 trn_extension_field_getlen_field(field), dos_ext);
   if (BUG(ret <= 0)) {
     goto err;
   }
   tor_assert(ret == (ssize_t) dos_ext_encoded_len);
 
   /* Finally, encode field into the cell extension. */
-  trn_cell_extension_add_fields(extensions, field);
+  trn_extension_add_fields(extensions, field);
 
   /* We've just add an extension field to the cell extensions so increment the
    * total number. */
-  trn_cell_extension_set_num(extensions,
-                             trn_cell_extension_get_num(extensions) + 1);
+  trn_extension_set_num(extensions, trn_extension_get_num(extensions) + 1);
 
   /* Cleanup. DoS extension has been encoded at this point. */
   trn_cell_extension_dos_free(dos_ext);
@@ -515,7 +514,7 @@ build_establish_intro_dos_extension(const hs_service_config_t *service_config,
   return 0;
 
  err:
-  trn_cell_extension_field_free(field);
+  trn_extension_field_free(field);
   trn_cell_extension_dos_free(dos_ext);
   return -1;
 }
@@ -526,18 +525,18 @@ build_establish_intro_dos_extension(const hs_service_config_t *service_config,
 
 /** Allocate and build all the ESTABLISH_INTRO cell extension. The given
  * extensions pointer is always set to a valid cell extension object. */
-STATIC trn_cell_extension_t *
+STATIC trn_extension_t *
 build_establish_intro_extensions(const hs_service_config_t *service_config,
                                  const hs_service_intro_point_t *ip)
 {
   int ret;
-  trn_cell_extension_t *extensions;
+  trn_extension_t *extensions;
 
   tor_assert(service_config);
   tor_assert(ip);
 
-  extensions = trn_cell_extension_new();
-  trn_cell_extension_set_num(extensions, 0);
+  extensions = trn_extension_new();
+  trn_extension_set_num(extensions, 0);
 
   /* If the defense has been enabled service side (by the operator with a
    * torrc option) and the intro point does support it. */
@@ -568,7 +567,7 @@ hs_cell_build_establish_intro(const char *circ_nonce,
   ssize_t cell_len = -1;
   uint16_t sig_len = ED25519_SIG_LEN;
   trn_cell_establish_intro_t *cell = NULL;
-  trn_cell_extension_t *extensions;
+  trn_extension_t *extensions;
 
   tor_assert(circ_nonce);
   tor_assert(service_config);
@@ -947,7 +946,7 @@ hs_cell_build_introduce1(const hs_cell_introduce1_data_t *data,
 {
   ssize_t cell_len;
   trn_cell_introduce1_t *cell;
-  trn_cell_extension_t *ext;
+  trn_extension_t *ext;
 
   tor_assert(data);
   tor_assert(cell_out);
@@ -956,9 +955,9 @@ hs_cell_build_introduce1(const hs_cell_introduce1_data_t *data,
   tor_assert(cell);
 
   /* Set extension data. None are used. */
-  ext = trn_cell_extension_new();
+  ext = trn_extension_new();
   tor_assert(ext);
-  trn_cell_extension_set_num(ext, 0);
+  trn_extension_set_num(ext, 0);
   trn_cell_introduce1_set_extensions(cell, ext);
 
   /* Set the authentication key. */
diff --git a/src/feature/hs/hs_cell.h b/src/feature/hs/hs_cell.h
index dc083ca03f..c25fd45567 100644
--- a/src/feature/hs/hs_cell.h
+++ b/src/feature/hs/hs_cell.h
@@ -115,9 +115,9 @@ void hs_cell_introduce1_data_clear(hs_cell_introduce1_data_t *data);
 
 #ifdef TOR_UNIT_TESTS
 
-#include "trunnel/hs/cell_common.h"
+#include "trunnel/extension.h"
 
-STATIC trn_cell_extension_t *
+STATIC trn_extension_t *
 build_establish_intro_extensions(const hs_service_config_t *service_config,
                                  const hs_service_intro_point_t *ip);
 
diff --git a/src/feature/hs/hs_circuit.c b/src/feature/hs/hs_circuit.c
index 0d7dd1c2b8..3347bdca07 100644
--- a/src/feature/hs/hs_circuit.c
+++ b/src/feature/hs/hs_circuit.c
@@ -35,7 +35,6 @@
 
 /* Trunnel. */
 #include "trunnel/ed25519_cert.h"
-#include "trunnel/hs/cell_common.h"
 #include "trunnel/hs/cell_establish_intro.h"
 
 #include "core/or/cpath_build_state_st.h"
diff --git a/src/feature/hs/hs_intropoint.c b/src/feature/hs/hs_intropoint.c
index b589e44cc3..0a656b78dd 100644
--- a/src/feature/hs/hs_intropoint.c
+++ b/src/feature/hs/hs_intropoint.c
@@ -20,7 +20,7 @@
 
 /* Trunnel */
 #include "trunnel/ed25519_cert.h"
-#include "trunnel/hs/cell_common.h"
+#include "trunnel/extension.h"
 #include "trunnel/hs/cell_establish_intro.h"
 #include "trunnel/hs/cell_introduce1.h"
 
@@ -155,14 +155,14 @@ hs_intro_send_intro_established_cell,(or_circuit_t *circ))
   uint8_t *encoded_cell = NULL;
   ssize_t encoded_len, result_len;
   trn_cell_intro_established_t *cell;
-  trn_cell_extension_t *ext;
+  trn_extension_t *ext;
 
   tor_assert(circ);
 
   /* Build the cell payload. */
   cell = trn_cell_intro_established_new();
-  ext = trn_cell_extension_new();
-  trn_cell_extension_set_num(ext, 0);
+  ext = trn_extension_new();
+  trn_extension_set_num(ext, 0);
   trn_cell_intro_established_set_extensions(cell, ext);
   /* Encode the cell to binary format. */
   encoded_len = trn_cell_intro_established_encoded_len(cell);
@@ -249,7 +249,7 @@ cell_dos_extension_parameters_are_valid(uint64_t intro2_rate_per_sec,
  * values, the DoS defenses is disabled on the circuit. */
 static void
 handle_establish_intro_cell_dos_extension(
-                                const trn_cell_extension_field_t *field,
+                                const trn_extension_field_t *field,
                                 or_circuit_t *circ)
 {
   ssize_t ret;
@@ -260,8 +260,8 @@ handle_establish_intro_cell_dos_extension(
   tor_assert(circ);
 
   ret = trn_cell_extension_dos_parse(&dos,
-                 trn_cell_extension_field_getconstarray_field(field),
-                 trn_cell_extension_field_getlen_field(field));
+                 trn_extension_field_getconstarray_field(field),
+                 trn_extension_field_getlen_field(field));
   if (ret < 0) {
     goto end;
   }
@@ -332,7 +332,7 @@ handle_establish_intro_cell_extensions(
                             const trn_cell_establish_intro_t *parsed_cell,
                             or_circuit_t *circ)
 {
-  const trn_cell_extension_t *extensions;
+  const trn_extension_t *extensions;
 
   tor_assert(parsed_cell);
   tor_assert(circ);
@@ -343,15 +343,15 @@ handle_establish_intro_cell_extensions(
   }
 
   /* Go over all extensions. */
-  for (size_t idx = 0; idx < trn_cell_extension_get_num(extensions); idx++) {
-    const trn_cell_extension_field_t *field =
-      trn_cell_extension_getconst_fields(extensions, idx);
+  for (size_t idx = 0; idx < trn_extension_get_num(extensions); idx++) {
+    const trn_extension_field_t *field =
+      trn_extension_getconst_fields(extensions, idx);
     if (BUG(field == NULL)) {
       /* The number of extensions should match the number of fields. */
       break;
     }
 
-    switch (trn_cell_extension_field_get_field_type(field)) {
+    switch (trn_extension_field_get_field_type(field)) {
     case TRUNNEL_CELL_EXTENSION_TYPE_DOS:
       /* After this, the circuit should be set for DoS defenses. */
       handle_establish_intro_cell_dos_extension(field, circ);
@@ -541,7 +541,7 @@ send_introduce_ack_cell(or_circuit_t *circ, uint16_t status)
   uint8_t *encoded_cell = NULL;
   ssize_t encoded_len, result_len;
   trn_cell_introduce_ack_t *cell;
-  trn_cell_extension_t *ext;
+  trn_extension_t *ext;
 
   tor_assert(circ);
 
@@ -550,8 +550,8 @@ send_introduce_ack_cell(or_circuit_t *circ, uint16_t status)
   cell = trn_cell_introduce_ack_new();
   ret = trn_cell_introduce_ack_set_status(cell, status);
   /* We have no cell extensions in an INTRODUCE_ACK cell. */
-  ext = trn_cell_extension_new();
-  trn_cell_extension_set_num(ext, 0);
+  ext = trn_extension_new();
+  trn_extension_set_num(ext, 0);
   trn_cell_introduce_ack_set_extensions(cell, ext);
   /* A wrong status is a very bad code flow error as this value is controlled
    * by the code in this file and not an external input. This means we use a
diff --git a/src/feature/hs/hs_service.c b/src/feature/hs/hs_service.c
index 2b3699422a..bf99ad69bd 100644
--- a/src/feature/hs/hs_service.c
+++ b/src/feature/hs/hs_service.c
@@ -59,7 +59,6 @@
 
 /* Trunnel */
 #include "trunnel/ed25519_cert.h"
-#include "trunnel/hs/cell_common.h"
 #include "trunnel/hs/cell_establish_intro.h"
 
 #ifdef HAVE_SYS_STAT_H