temp_channel_id: move to common

We actually do need this for dualopend's, specifically for returning
errors to open_channel2

common/channel_id.c

@@ -1,6 +1,7 @@
 #include <bitcoin/pubkey.h>
 #include <bitcoin/tx.h>
 #include <common/channel_id.h>
+#include <common/pseudorand.h>
 #include <common/type_to_string.h>
 #include <wire/wire.h>
 
@@ -46,6 +47,23 @@ void derive_channel_id_v2(struct channel_id *channel_id,
 	memcpy(channel_id, &sha, sizeof(*channel_id));
 }
 
+/* BOLT #2:
+ *
+ * The sending node:
+ *...
+ *  - MUST ensure `temporary_channel_id` is unique from any other channel ID
+ *    with the same peer.
+ */
+void temporary_channel_id(struct channel_id *channel_id)
+{
+	size_t i;
+
+	/* Randomness FTW. */
+	for (i = 0; i < sizeof(*channel_id); i++)
+		channel_id->id[i] = pseudorand(256);
+}
+
+
 void towire_channel_id(u8 **pptr, const struct channel_id *channel_id)
 {
 	towire(pptr, channel_id, sizeof(*channel_id));

common/channel_id.h

@@ -26,6 +26,8 @@ void derive_channel_id(struct channel_id *channel_id,
 void derive_channel_id_v2(struct channel_id *channel_id,
 			  const struct pubkey *basepoint_1,
 			  const struct pubkey *basepoint_2);
+
+void temporary_channel_id(struct channel_id *channel_id);
 /* Marshalling/unmarshalling functions */
 void towire_channel_id(u8 **pptr, const struct channel_id *channel_id);
 void fromwire_channel_id(const u8 **cursor, size_t *max,

openingd/openingd.c

@@ -33,7 +33,6 @@
 #include <common/peer_failed.h>
 #include <common/peer_status_wiregen.h>
 #include <common/penalty_base.h>
-#include <common/pseudorand.h>
 #include <common/read_peer_msg.h>
 #include <common/status.h>
 #include <common/subdaemon.h>
@@ -214,22 +213,6 @@ static void set_reserve(struct state *state, const struct amount_sat dust_limit)
 			= dust_limit;
 }
 
-/* BOLT #2:
- *
- * The sending node:
- *...
- *  - MUST ensure `temporary_channel_id` is unique from any other channel ID
- *    with the same peer.
- */
-static void temporary_channel_id(struct channel_id *channel_id)
-{
-	size_t i;
-
-	/* Randomness FTW. */
-	for (i = 0; i < sizeof(*channel_id); i++)
-		channel_id->id[i] = pseudorand(256);
-}
-
 /*~ Handle random messages we might get during opening negotiation, (eg. gossip)
  * returning the first non-handled one, or NULL if we aborted negotiation. */
 static u8 *opening_negotiate_msg(const tal_t *ctx, struct state *state,

wire/test/Makefile

@@ -10,6 +10,7 @@ ALL_C_SOURCES += $(WIRE_TEST_SRC)
 ALL_TEST_PROGRAMS += $(WIRE_TEST_PROGRAMS)
 
 WIRE_TEST_COMMON_OBJS :=		\
+	common/pseudorand.o		\
 	common/setup.o			\
 	common/utils.o