From ef86ee0bae22da7948c8f03899b53cbb55e80a06 Mon Sep 17 00:00:00 2001
From: Christian Decker <decker.christian@gmail.com>
Date: Tue, 3 Mar 2020 18:32:06 +0100
Subject: [PATCH] sphinx: Migrate sphinx compression to new interface

It also removes the duplicate compression code and serialization code.
---
 common/sphinx.c  | 26 +-------------------------
 common/sphinx.h  |  9 ---------
 devtools/onion.c | 18 ++++++++++++------
 3 files changed, 13 insertions(+), 40 deletions(-)

diff --git a/common/sphinx.c b/common/sphinx.c
index 4adea1e0c..7b51625e1 100644
--- a/common/sphinx.c
+++ b/common/sphinx.c
@@ -149,30 +149,6 @@ u8 *serialize_onionpacket(
 	return dst;
 }
 
-u8 *serialize_compressed_onion(const tal_t *ctx,
-			       const struct sphinx_path *sp,
-			       const struct onionpacket *packet)
-{
-	u8 *dst;
-	u8 der[PUBKEY_CMPR_LEN];
-	size_t payloads_size = sphinx_path_payloads_size(sp);
-	size_t max_prefill  = ROUTING_INFO_SIZE - payloads_size;
-	size_t rv_onion_size = TOTAL_PACKET_SIZE - max_prefill;
-	int p = 0;
-
-	assert(sp->rendezvous_id != NULL);
-
-	dst = tal_arr(ctx, u8, rv_onion_size);
-
-	pubkey_to_der(der, &packet->ephemeralkey);
-	write_buffer(dst, &packet->version, 1, &p);
-	write_buffer(dst, der, sizeof(der), &p);
-	write_buffer(dst, packet->routinginfo, ROUTING_INFO_SIZE - max_prefill, &p);
-	write_buffer(dst, packet->mac, sizeof(packet->mac), &p);
-	return dst;
-}
-
-
 enum onion_type parse_onionpacket(const u8 *src,
 				  const size_t srclen,
 				  struct onionpacket *dest)
@@ -810,7 +786,7 @@ sphinx_compress(const tal_t *ctx, const struct onionpacket *packet,
 	size_t payloads_size = sphinx_path_payloads_size(path);
 
 	/* We can't compress an onion that doesn't have a rendez-vous node. */
-	if (path->rendezvous_id)
+	if (path->rendezvous_id == NULL)
 		return NULL;
 
 	res = tal(ctx, struct sphinx_compressed_onion);
diff --git a/common/sphinx.h b/common/sphinx.h
index dc9caeb2f..ccb57cd1b 100644
--- a/common/sphinx.h
+++ b/common/sphinx.h
@@ -234,15 +234,6 @@ void sphinx_add_hop(struct sphinx_path *path, const struct pubkey *pubkey,
  */
 size_t sphinx_path_payloads_size(const struct sphinx_path *path);
 
-/**
- * Compress a rendez-vous onion by removing the unused blinded middle
- * part. This middle part can be regenerated by the node processing this
- * onion.
- */
-u8 *serialize_compressed_onion(const tal_t *ctx,
-			       const struct sphinx_path *sp,
-			       const struct onionpacket *packet);
-
 /**
  * Set the rendez-vous node_id and make the onion generated from the
  * sphinx_path compressible. To unset pass in a NULL rendezvous_id.
diff --git a/devtools/onion.c b/devtools/onion.c
index 49008e6ae..e9e13ef01 100644
--- a/devtools/onion.c
+++ b/devtools/onion.c
@@ -32,7 +32,9 @@ static void do_generate(int argc, char **argv,
 	struct secret session_key;
 	struct secret *shared_secrets;
 	struct sphinx_path *sp;
-
+	struct sphinx_compressed_onion *comp;
+	u8 *serialized;
+	struct onionpacket *packet;
 	const u8* tmp_assocdata =tal_dup_arr(ctx, u8, assocdata,
 					  ASSOC_DATA_SIZE, 0);
 	memset(&session_key, 'A', sizeof(struct secret));
@@ -93,13 +95,17 @@ static void do_generate(int argc, char **argv,
 		}
 	}
 
-	struct onionpacket *res = create_onionpacket(ctx, sp, &shared_secrets);
+	packet = create_onionpacket(ctx, sp, &shared_secrets);
 
-	if (rvnode_id != NULL)
-		printf("Rendezvous onion: %s\n",
-		       tal_hex(ctx, serialize_compressed_onion(ctx, sp, res)));
+	if (rvnode_id != NULL) {
+		comp = sphinx_compress(ctx, packet, sp);
+		serialized = sphinx_compressed_onion_serialize(ctx, comp);
+		printf("Rendezvous onion: %s\n", tal_hex(ctx, serialized));
+	} else {
+		assert(sphinx_compress(ctx, packet, sp) == NULL);
+	}
 
-	u8 *serialized = serialize_onionpacket(ctx, res);
+	serialized = serialize_onionpacket(ctx, packet);
 	if (!serialized)
 		errx(1, "Error serializing message.");
 	printf("%s\n", tal_hex(ctx, serialized));