recv_block: ask for block contents on reinject.

Now we query blocks out of order, we often will get a block through
reinjection (once we finally get its prev) rather than directly from
the packet path.  Assume that if this happens, we are syncing, and thus
want to ask about contents and children.

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

recv_block.c

@@ -127,7 +127,7 @@ static void ask_block_contents(struct state *state, const struct block *b)
 /* peer is NULL if from generator, re-trying detached block or jsonrpc. */
 static enum protocol_ecode
 recv_block(struct state *state, struct log *log, struct peer *peer,
-	   const tal_t *pkt_ctx, const struct block_info *bi,
+	   const tal_t *pkt_ctx, const struct block_info *bi, bool need_contents,
 	   struct block **block)
 {
 	struct block *b, *prev;
@@ -184,7 +184,7 @@ recv_block(struct state *state, struct log *log, struct peer *peer,
 						   bad_shard);
 		} else {
 			/* If we're syncing, ask about children, contents */
-			if (peer && peer->we_are_syncing) {
+			if (need_contents) {
 				/* FIXME: Don't do these if below horizon */
 				todo_add_get_children(state, &b->sha);
 				get_block_contents(state, b);
@@ -229,7 +229,7 @@ recv_block_pkt(struct state *state, struct log *log, struct peer *peer,
 		return e;
 	}
 
-	return recv_block(state, log, peer, pkt, &bi, block);
+	return recv_block(state, log, peer, pkt, &bi, peer->we_are_syncing, block);
 }
 
 static struct txptr_with_ref
@@ -525,7 +525,8 @@ void recv_block_reinject(struct state *state,
 {
 	struct block *b;
 
-	recv_block(state, state->log, NULL, pkt_ctx, bi, &b);
+	/* A reinject implies we are catching up: explicitly ask for contents. */
+	recv_block(state, state->log, NULL, pkt_ctx, bi, true, &b);
 }
 
 static char *json_submitblock(struct json_connection *jcon,
@@ -553,7 +554,7 @@ static char *json_submitblock(struct json_connection *jcon,
 	if (e != PROTOCOL_ECODE_NONE)
 		return (char *)ecode_name(e);
 
-	e = recv_block(jcon->state, jcon->log, NULL, data, &bi, &block);
+	e = recv_block(jcon->state, jcon->log, NULL, data, &bi, false, &block);
 	if (e != PROTOCOL_ECODE_NONE)
 		return (char *)ecode_name(e);