gossipd: handle a "push" marker into the gossip_store.

This tells clients to ignore any timestamp_filter and always
send this message when it sees it.

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

common/gossip_store.c

@@ -84,6 +84,7 @@ u8 *gossip_store_next(const tal_t *ctx, struct per_peer_state *pps)
 	while (!msg) {
 		struct gossip_hdr hdr;
 		u32 msglen, checksum, timestamp;
+		bool push;
 		int type, r;
 
 		r = read(pps->gossip_store_fd, &hdr, sizeof(hdr));
@@ -99,12 +100,15 @@ u8 *gossip_store_next(const tal_t *ctx, struct per_peer_state *pps)
 		if (be32_to_cpu(hdr.len) & GOSSIP_STORE_LEN_DELETED_BIT) {
 			/* Skip over it. */
 			lseek(pps->gossip_store_fd,
-			      be32_to_cpu(hdr.len) & ~GOSSIP_STORE_LEN_DELETED_BIT,
+			      be32_to_cpu(hdr.len) & GOSSIP_STORE_LEN_MASK,
 			      SEEK_CUR);
 			continue;
 		}
 
 		msglen = be32_to_cpu(hdr.len);
+		push = (msglen & GOSSIP_STORE_LEN_PUSH_BIT);
+		msglen &= GOSSIP_STORE_LEN_MASK;
+
 		checksum = be32_to_cpu(hdr.crc);
 		timestamp = be32_to_cpu(hdr.timestamp);
 		msg = tal_arr(ctx, u8, msglen);
@@ -135,7 +139,7 @@ u8 *gossip_store_next(const tal_t *ctx, struct per_peer_state *pps)
 		    && type != WIRE_CHANNEL_UPDATE
 		    && type != WIRE_NODE_ANNOUNCEMENT)
 			msg = tal_free(msg);
-		else if (!timestamp_filter(pps, timestamp))
+		else if (!push && !timestamp_filter(pps, timestamp))
 			msg = tal_free(msg);
 	}
 

common/gossip_store.h

@@ -17,6 +17,15 @@ struct per_peer_state;
  */
 #define GOSSIP_STORE_LEN_DELETED_BIT 0x80000000U
 
+/**
+ * Bit of length we use to mark an important record.
+ */
+#define GOSSIP_STORE_LEN_PUSH_BIT 0x40000000U
+
+/* Mask for extracting just the length part of len field */
+#define GOSSIP_STORE_LEN_MASK \
+	(~(GOSSIP_STORE_LEN_PUSH_BIT | GOSSIP_STORE_LEN_DELETED_BIT))
+
 /**
  * gossip_hdr -- On-disk format header.
  */

devtools/dump-gossipstore.c

@@ -55,11 +55,12 @@ int main(int argc, char *argv[])
 		struct amount_sat sat;
 		u32 msglen = be32_to_cpu(hdr.len);
 		u8 *msg, *inner;
-		bool deleted;
+		bool deleted, push;
 
 		deleted = (msglen & GOSSIP_STORE_LEN_DELETED_BIT);
+		push = (msglen & GOSSIP_STORE_LEN_PUSH_BIT);
 
-		msglen &= ~GOSSIP_STORE_LEN_DELETED_BIT;
+		msglen &= GOSSIP_STORE_LEN_MASK;
 		msg = tal_arr(NULL, u8, msglen);
 		if (read(fd, msg, msglen) != msglen)
 			errx(1, "%zu: Truncated file?", off);
@@ -68,7 +69,9 @@ int main(int argc, char *argv[])
 		    != crc32c(be32_to_cpu(hdr.timestamp), msg, msglen))
 			warnx("Checksum verification failed");
 
-		printf("%zu: %s", off, deleted ? "DELETED " : "");
+		printf("%zu: %s%s", off,
+		       deleted ? "DELETED " : "",
+		       push ? "PUSH " : "");
 		if (deleted && !print_deleted) {
 			printf("\n");
 			goto end;

gossipd/gossip_store.c

@@ -157,7 +157,7 @@ static u32 gossip_store_compact_offline(void)
 		size_t msglen;
 		u8 *msg;
 
-		msglen = (be32_to_cpu(hdr.len) & ~GOSSIP_STORE_LEN_DELETED_BIT);
+		msglen = (be32_to_cpu(hdr.len) & GOSSIP_STORE_LEN_MASK);
 		msg = tal_arr(NULL, u8, msglen);
 		if (!read_all(old_fd, msg, msglen)) {
 			status_broken("gossip_store_compact_offline: reading msg len %zu from store: %s",
@@ -272,6 +272,9 @@ static size_t transfer_store_msg(int from_fd, size_t from_off,
 		return 0;
 	}
 
+	/* Ignore any non-length bits (e.g. push) */
+	msglen &= GOSSIP_STORE_LEN_MASK;
+
 	/* FIXME: Reuse buffer? */
 	msg = tal_arr(tmpctx, u8, sizeof(hdr) + msglen);
 	memcpy(msg, &hdr, sizeof(hdr));
@@ -395,7 +398,7 @@ bool gossip_store_compact(struct gossip_store *gs)
 		u32 msglen, wlen;
 		int msgtype;
 
-		msglen = (be32_to_cpu(hdr.len) & ~GOSSIP_STORE_LEN_DELETED_BIT);
+		msglen = (be32_to_cpu(hdr.len) & GOSSIP_STORE_LEN_MASK);
 		if (be32_to_cpu(hdr.len) & GOSSIP_STORE_LEN_DELETED_BIT) {
 			off += sizeof(hdr) + msglen;
 			deleted++;
@@ -547,7 +550,7 @@ static u32 delete_by_index(struct gossip_store *gs, u32 index, int type)
 	gs->deleted++;
 
 	return index + sizeof(struct gossip_hdr)
-		+ (be32_to_cpu(belen) & ~GOSSIP_STORE_LEN_DELETED_BIT);
+		+ (be32_to_cpu(belen) & GOSSIP_STORE_LEN_MASK);
 }
 
 void gossip_store_delete(struct gossip_store *gs,
@@ -595,7 +598,7 @@ const u8 *gossip_store_get(const tal_t *ctx,
 			      "/%"PRIu64"",
 			      offset, gs->len);
 
-	msglen = be32_to_cpu(hdr.len);
+	msglen = (be32_to_cpu(hdr.len) & GOSSIP_STORE_LEN_MASK);
 	checksum = be32_to_cpu(hdr.crc);
 	msg = tal_arr(ctx, u8, msglen);
 	if (pread(gs->fd, msg, msglen, offset + sizeof(hdr)) != msglen)
@@ -651,7 +654,7 @@ u32 gossip_store_load(struct routing_state *rstate, struct gossip_store *gs)
 
 	gs->writable = false;
 	while (pread(gs->fd, &hdr, sizeof(hdr), gs->len) == sizeof(hdr)) {
-		msglen = be32_to_cpu(hdr.len) & ~GOSSIP_STORE_LEN_DELETED_BIT;
+		msglen = be32_to_cpu(hdr.len) & GOSSIP_STORE_LEN_MASK;
 		checksum = be32_to_cpu(hdr.crc);
 		msg = tal_arr(tmpctx, u8, msglen);