common: add struct onionreply

I really want a type which means "I am a wrapped onion reply" as separate
from "I am a normal wire msg".  Currently both user u8 *, and I got very
confused trying to figure out where each one was an unwrapped error msg,
or where it still needed (un)wrapping.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

common/Makefile

@@ -41,6 +41,7 @@ COMMON_SRC_NOGEN :=				\
 	common/msg_queue.c			\
 	common/node_id.c			\
 	common/onion.c				\
+	common/onionreply.c			\
 	common/param.c				\
 	common/per_peer_state.c			\
 	common/peer_billboard.c			\

common/onionreply.c

@@ -0,0 +1,40 @@
+#include <ccan/cast/cast.h>
+#include <common/onionreply.h>
+#include <wire/wire.h>
+
+void towire_onionreply(u8 **cursor, const struct onionreply *r)
+{
+	towire_u16(cursor, tal_count(r->contents));
+	towire_u8_array(cursor, r->contents, tal_count(r->contents));
+}
+
+struct onionreply *fromwire_onionreply(const tal_t *ctx,
+				       const u8 **cursor, size_t *max)
+{
+	struct onionreply *r = tal(ctx, struct onionreply);
+	r->contents = tal_arr(r, u8, fromwire_u16(cursor, max));
+	fromwire_u8_array(cursor, max, r->contents, tal_count(r->contents));
+	if (!*cursor)
+		return tal_free(r);
+	return r;
+}
+
+struct onionreply *dup_onionreply(const tal_t *ctx,
+				  const struct onionreply *r TAKES)
+{
+	struct onionreply *n;
+
+	if (taken(r))
+		return cast_const(struct onionreply *, tal_steal(ctx, r));
+
+	n = tal(ctx, struct onionreply);
+	n->contents = tal_dup_arr(n, u8, r->contents, tal_count(r->contents), 0);
+	return n;
+}
+
+struct onionreply *new_onionreply(const tal_t *ctx, const u8 *contents TAKES)
+{
+	struct onionreply *r = tal(ctx, struct onionreply);
+	r->contents = tal_dup_arr(r, u8, contents, tal_count(contents), 0);
+	return r;
+}

common/onionreply.h

@@ -0,0 +1,24 @@
+#ifndef LIGHTNING_COMMON_ONIONREPLY_H
+#define LIGHTNING_COMMON_ONIONREPLY_H
+#include "config.h"
+#include <ccan/short_types/short_types.h>
+#include <ccan/tal/tal.h>
+
+/* A separate type for an onion reply, to differentiate from a wire msg. */
+struct onionreply {
+	u8 *contents;
+};
+
+/**
+ * Wire marshalling routines for onionreply
+ */
+void towire_onionreply(u8 **cursor, const struct onionreply *r);
+struct onionreply *fromwire_onionreply(const tal_t *ctx,
+				       const u8 **cursor, size_t *max);
+
+
+struct onionreply *dup_onionreply(const tal_t *ctx,
+				  const struct onionreply *r TAKES);
+
+struct onionreply *new_onionreply(const tal_t *ctx, const u8 *contents TAKES);
+#endif /* LIGHTNING_COMMON_ONIONREPLY_H */

tools/generate-wire.py

@@ -224,6 +224,7 @@ class Type(FieldSet):
         'bitcoin_tx_output',
         'exclude_entry',
         'fee_states',
+        'onionreply',
     ]
 
     # Some BOLT types are re-typed based on their field name

wallet/db.c

@@ -3,6 +3,7 @@
 #include <ccan/array_size/array_size.h>
 #include <ccan/tal/str/str.h>
 #include <common/node_id.h>
+#include <common/onionreply.h>
 #include <common/version.h>
 #include <inttypes.h>
 #include <lightningd/lightningd.h>
@@ -1227,6 +1228,11 @@ void db_bind_json_escape(struct db_stmt *stmt, int pos,
 	db_bind_text(stmt, pos, esc->s);
 }
 
+void db_bind_onionreply(struct db_stmt *stmt, int pos, const struct onionreply *r)
+{
+	db_bind_blob(stmt, pos, r->contents, tal_bytelen(r->contents));
+}
+
 void db_column_preimage(struct db_stmt *stmt, int col,
 			struct preimage *preimage)
 {
@@ -1409,6 +1415,16 @@ void db_column_txid(struct db_stmt *stmt, int pos, struct bitcoin_txid *t)
 	db_column_sha256d(stmt, pos, &t->shad);
 }
 
+struct onionreply *db_column_onionreply(const tal_t *ctx,
+					struct db_stmt *stmt, int col)
+{
+	struct onionreply *r = tal(ctx, struct onionreply);
+	r->contents = tal_dup_arr(r, u8,
+				  db_column_blob(stmt, col),
+				  db_column_bytes(stmt, col), 0);
+	return r;
+}
+
 bool db_exec_prepared_v2(struct db_stmt *stmt TAKES)
 {
 	bool ret = stmt->db->config->exec_fn(stmt);

wallet/db.h

@@ -18,6 +18,7 @@
 struct lightningd;
 struct log;
 struct node_id;
+struct onionreply;
 struct db_stmt;
 struct db;
 
@@ -120,6 +121,8 @@ void db_bind_amount_sat(struct db_stmt *stmt, int pos,
 			const struct amount_sat *sat);
 void db_bind_json_escape(struct db_stmt *stmt, int pos,
 			 const struct json_escape *esc);
+void db_bind_onionreply(struct db_stmt *stmt, int col,
+			const struct onionreply *r);
 
 bool db_step(struct db_stmt *stmt);
 u64 db_column_u64(struct db_stmt *stmt, int col);
@@ -151,6 +154,9 @@ bool db_column_signature(struct db_stmt *stmt, int col,
 struct timeabs db_column_timeabs(struct db_stmt *stmt, int col);
 struct bitcoin_tx *db_column_tx(const tal_t *ctx, struct db_stmt *stmt, int col);
 
+struct onionreply *db_column_onionreply(const tal_t *ctx,
+					struct db_stmt *stmt, int col);
+
 #define db_column_arr(ctx, stmt, col, type)			\
 	((type *)db_column_arr_((ctx), (stmt), (col),		\
 				sizeof(type), TAL_LABEL(type, "[]"),	\