common/gossip_store: avoid fd pass for new store, use end marker.

This is also simpler.

Signed-off-by: Rusty Russell <[email protected]>

closingd/Makefile

@@ -59,6 +59,7 @@ CLOSINGD_COMMON_OBJS :=				\
 	common/version.o			\
 	common/wire_error.o			\
 	common/wireaddr.o			\
+	gossipd/gossip_store_wiregen.o		\
 	gossipd/gossipd_peerd_wiregen.o
 
 ifeq ($(EXPERIMENTAL_FEATURES),1)

common/gossip_store.c

@@ -7,7 +7,11 @@
 #include <common/status.h>
 #include <common/utils.h>
 #include <errno.h>
+#include <fcntl.h>
+#include <gossipd/gossip_store_wiregen.h>
 #include <inttypes.h>
+#include <sys/stat.h>
+#include <sys/types.h>
 #include <unistd.h>
 #include <wire/peer_wire.h>
 
@@ -74,6 +78,32 @@ static void undo_read(int fd, int len, size_t wanted)
 	lseek(fd, -len, SEEK_CUR);
 }
 
+static void reopen_gossip_store(struct per_peer_state *pps,
+				const u8 *msg)
+{
+	u64 equivalent_offset;
+	int newfd;
+
+	if (!fromwire_gossip_store_ended(msg, &equivalent_offset))
+		status_failed(STATUS_FAIL_GOSSIP_IO,
+			      "Bad gossipd GOSSIP_STORE_ENDED msg: %s",
+			      tal_hex(tmpctx, msg));
+
+	newfd = open(GOSSIP_STORE_FILENAME, O_RDONLY);
+	if (newfd < 0)
+		status_failed(STATUS_FAIL_INTERNAL_ERROR,
+			      "Cannot open %s: %s",
+			      GOSSIP_STORE_FILENAME,
+			      strerror(errno));
+
+	status_debug("gossip_store at end, new fd moved to %"PRIu64,
+		     equivalent_offset);
+	lseek(newfd, equivalent_offset, SEEK_SET);
+
+	close(pps->gossip_store_fd);
+	pps->gossip_store_fd = newfd;
+}
+
 u8 *gossip_store_next(const tal_t *ctx, struct per_peer_state *pps)
 {
 	u8 *msg = NULL;
@@ -134,9 +164,11 @@ u8 *gossip_store_next(const tal_t *ctx, struct per_peer_state *pps)
 			continue;
 		}
 
-		/* Ignore gossipd internal messages. */
 		type = fromwire_peektype(msg);
-		if (type != WIRE_CHANNEL_ANNOUNCEMENT
+		if (type == WIRE_GOSSIP_STORE_ENDED)
+			reopen_gossip_store(pps, msg);
+		/* Ignore gossipd internal messages. */
+		else if (type != WIRE_CHANNEL_ANNOUNCEMENT
 		    && type != WIRE_CHANNEL_UPDATE
 		    && type != WIRE_NODE_ANNOUNCEMENT)
 			msg = tal_free(msg);
@@ -146,54 +178,3 @@ u8 *gossip_store_next(const tal_t *ctx, struct per_peer_state *pps)
 
 	return msg;
 }
-
-/* newfd is at offset 1.  We need to adjust it to similar offset as our
- * current one. */
-void gossip_store_switch_fd(struct per_peer_state *pps,
-			    int newfd, u64 offset_shorter)
-{
-	u64 cur = lseek(pps->gossip_store_fd, 0, SEEK_CUR);
-
-	/* If we're already at end (common), we know where to go in new one. */
-	if (cur == lseek(pps->gossip_store_fd, 0, SEEK_END)) {
-		status_debug("gossip_store at end, new fd moved to %"PRIu64,
-			     cur - offset_shorter);
-		assert(cur > offset_shorter);
-		lseek(newfd, cur - offset_shorter, SEEK_SET);
-	} else if (cur > offset_shorter) {
-		/* We're part way through.  Worst case, we should move back by
-		 * offset_shorter (that's how much the *end* moved), but in
-		 * practice we'll probably end up retransmitting some stuff */
-		u64 target = cur - offset_shorter;
-		size_t num = 0;
-
-		status_debug("gossip_store new fd moving back %"PRIu64
-			     " to %"PRIu64,
-			     cur, target);
-		cur = 1;
-		while (cur < target) {
-			u32 msglen;
-			struct gossip_hdr hdr;
-
-			if (read(newfd, &hdr, sizeof(hdr)) != sizeof(hdr))
-				status_failed(STATUS_FAIL_INTERNAL_ERROR,
-					      "gossip_store: "
-					      "can't read hdr offset %"PRIu64
-					      " in new store target %"PRIu64,
-					      cur, target);
-			/* Skip over it. */
-			msglen = (be32_to_cpu(hdr.len)
-				  & ~GOSSIP_STORE_LEN_DELETED_BIT);
-			cur = lseek(newfd, msglen, SEEK_CUR);
-			num++;
-		}
-		status_debug("gossip_store: skipped %zu records to %"PRIu64,
-			     num, cur);
-	} else
-		status_debug("gossip_store new fd moving back %"PRIu64
-			     " to start (offset_shorter=%"PRIu64")",
-			     cur, offset_shorter);
-
-	close(pps->gossip_store_fd);
-	pps->gossip_store_fd = newfd;
-}

common/read_peer_msg.c

@@ -108,15 +108,9 @@ bool is_wrong_channel(const u8 *msg, const struct channel_id *expected,
 void handle_gossip_msg(struct per_peer_state *pps, const u8 *msg TAKES)
 {
 	u8 *gossip;
-	u64 offset_shorter;
 
-	if (fromwire_gossipd_new_store_fd(msg, &offset_shorter)) {
-		gossip_store_switch_fd(pps, fdpass_recv(pps->gossip_fd),
-				       offset_shorter);
-		goto out;
-	} else
-		/* It's a raw gossip msg: this copies or takes() */
-		gossip = tal_dup_talarr(tmpctx, u8, msg);
+	/* It's a raw gossip msg: this copies or takes() */
+	gossip = tal_dup_talarr(tmpctx, u8, msg);
 
 	/* Gossipd can send us gossip messages, OR errors */
 	if (fromwire_peektype(gossip) == WIRE_ERROR) {
@@ -125,10 +119,6 @@ void handle_gossip_msg(struct per_peer_state *pps, const u8 *msg TAKES)
 	} else {
 		sync_crypto_write(pps, gossip);
 	}
-
-out:
-	if (taken(msg))
-		tal_free(msg);
 }
 
 /* takes iff returns true */

gossipd/gossip_store.c

@@ -465,7 +465,7 @@ bool gossip_store_compact(struct gossip_store *gs)
 {
 	size_t count = 0, deleted = 0;
 	int fd;
-	u64 off, len = sizeof(gs->version), oldlen, idx;
+	u64 off, len = sizeof(gs->version), idx;
 	struct offmap *offmap;
 	struct gossip_hdr hdr;
 	struct offmap_iter oit;
@@ -578,18 +578,15 @@ bool gossip_store_compact(struct gossip_store *gs)
 	    deleted, count, len);
 
 	/* Write end marker now new one is ready */
-	oldlen = gs->len;
 	append_msg(gs->fd, towire_gossip_store_ended(tmpctx, len),
-		   0, false, &oldlen);
+		   0, false, &gs->len);
 
 	gs->count = count;
 	gs->deleted = 0;
-	off = gs->len - len;
 	gs->len = len;
 	close(gs->fd);
 	gs->fd = fd;
 
-	update_peers_broadcast_index(gs->peers, off);
 	return true;
 
 unlink_disable:

gossipd/gossipd.c

@@ -281,32 +281,6 @@ static u8 *handle_channel_update_msg(struct peer *peer, const u8 *msg)
 	return NULL;
 }
 
-/*~ When we compact the gossip store, all the broadcast indexs move.
- * We simply offset everyone, which means in theory they could retransmit
- * some, but that's a lesser evil than skipping some. */
-void update_peers_broadcast_index(struct list_head *peers, u32 offset)
-{
-	struct peer *peer, *next;
-
-	list_for_each_safe(peers, peer, next, list) {
-		int gs_fd;
-		/*~ Since store has been compacted, they need a new fd for the
-		 * new store.  We also tell them how much this is shrunk, so
-		 * they can (approximately) tell where to start in the new store.
-		 */
-		gs_fd = gossip_store_readonly_fd(peer->daemon->rstate->gs);
-		if (gs_fd < 0) {
-			status_broken("Can't get read-only gossip store fd:"
-				      " killing peer");
-			tal_free(peer);
-		} else {
-			u8 *msg = towire_gossipd_new_store_fd(NULL, offset);
-			daemon_conn_send(peer->dc, take(msg));
-			daemon_conn_send_fd(peer->dc, gs_fd);
-		}
-	}
-}
-
 /*~ For simplicity, all pings and pongs are forwarded to us here in gossipd. */
 static u8 *handle_ping(struct peer *peer, const u8 *ping)
 {
@@ -522,7 +496,6 @@ static struct io_plan *peer_msg_in(struct io_conn *conn,
 
 	/* These are the ones we send, not them */
 	case WIRE_GOSSIPD_GET_UPDATE_REPLY:
-	case WIRE_GOSSIPD_NEW_STORE_FD:
 		break;
 	}
 

gossipd/gossipd_peerd_wire.csv

@@ -22,11 +22,6 @@ msgdata,gossipd_local_channel_update,fee_base_msat,u32,
 msgdata,gossipd_local_channel_update,fee_proportional_millionths,u32,
 msgdata,gossipd_local_channel_update,htlc_maximum_msat,amount_msat,
 
-# Update your gossip_store fd: + gossip_store_fd
-msgtype,gossipd_new_store_fd,3505
-# How much shorter the new store is, so you can offset streaming.
-msgdata,gossipd_new_store_fd,offset_shorter,u64,
-
 # Send this channel_announcement
 msgtype,gossipd_local_channel_announcement,3506
 msgdata,gossipd_local_channel_announcement,len,u16,

openingd/Makefile

@@ -82,8 +82,8 @@ OPENINGD_COMMON_OBJS :=				\
 	common/version.o			\
 	common/wire_error.o			\
 	common/wireaddr.o			\
-	gossipd/gossipd_peerd_wiregen.o		\
-	lightningd/gossip_msg.o
+	gossipd/gossip_store_wiregen.o		\
+	gossipd/gossipd_peerd_wiregen.o
 
 ifeq ($(EXPERIMENTAL_FEATURES),1)
 OPENINGD_COMMON_OBJS += common/psbt_open.o