rework the HELLO logic inside FT-FW

4 files changed, 59 insertions, 8 deletions

diff --git a/ChangeLog b/ChangeLog
index 597206a..14ba054 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -36,6 +36,7 @@ o add Mcast[Snd|Rcv]SocketBuffer clauses to tune multicast socket buffers
 o add missing string.h required by strdup in config parsing
 o add eventfd emulation to communicate receiver -> sender
 o add best effort replication protocol (aka NOTRACK)
+o rework the HELLO logic inside FT-FW
 
 version 0.9.6 (2008/03/08)
 ------------------------------
diff --git a/include/network.h b/include/network.h
index baa1eba..777be11 100644
--- a/include/network.h
+++ b/include/network.h
@@ -31,6 +31,8 @@ enum {
 	NET_F_NACK 	= (1 << 2),
 	NET_F_ACK 	= (1 << 3),
 	NET_F_ALIVE 	= (1 << 4),
+	NET_F_HELLO	= (1 << 5),
+	NET_F_HELLO_BACK= (1 << 6),
 };
 
 enum {
@@ -63,6 +65,12 @@ enum {
 	SEQ_BEFORE,
 };
 
+enum {
+	SAY_HELLO,
+	HELLO_BACK,
+	HELLO_DONE,
+};
+
 int mcast_track_seq(uint32_t seq, uint32_t *exp_seq);
 void mcast_track_update_seq(uint32_t seq);
 int mcast_track_is_seq_set(void);
@@ -74,12 +82,14 @@ void mcast_buffered_destroy(void);
 int mcast_buffered_send_netmsg(struct mcast_sock *m, void *data, size_t len);
 ssize_t mcast_buffered_pending_netmsg(struct mcast_sock *m);
 
-#define IS_DATA(x)	(x->flags == 0)
+#define IS_DATA(x)	((x->flags & ~(NET_F_HELLO | NET_F_HELLO_BACK)) == 0)
 #define IS_ACK(x)	(x->flags & NET_F_ACK)
 #define IS_NACK(x)	(x->flags & NET_F_NACK)
 #define IS_RESYNC(x)	(x->flags & NET_F_RESYNC)
 #define IS_ALIVE(x)	(x->flags & NET_F_ALIVE)
 #define IS_CTL(x)	IS_ACK(x) || IS_NACK(x) || IS_RESYNC(x) || IS_ALIVE(x)
+#define IS_HELLO(x)	(x->flags & NET_F_HELLO)
+#define IS_HELLO_BACK(x)(x->flags & NET_F_HELLO_BACK)
 
 #define HDR_NETWORK2HOST(x)						\
 ({									\
diff --git a/src/sync-ftfw.c b/src/sync-ftfw.c
index adfdda9..42005c4 100644
--- a/src/sync-ftfw.c
+++ b/src/sync-ftfw.c
@@ -52,6 +52,7 @@ static uint32_t window;
 static uint32_t ack_from;
 static int ack_from_set = 0;
 static struct alarm_block alive_alarm;
+static int hello_state = SAY_HELLO;
 
 /* XXX: alive message expiration configurable */
 #define ALIVE_INT 1
@@ -97,6 +98,16 @@ static void tx_queue_add_ctlmsg(uint32_t flags, uint32_t from, uint32_t to)
 		.to    = to,
 	};
 
+	switch(hello_state) {
+	case SAY_HELLO:
+		ack.flags |= NET_F_HELLO;
+		break;
+	case HELLO_BACK:
+		ack.flags |= NET_F_HELLO_BACK;
+		hello_state = HELLO_DONE;
+		break;
+	}
+
 	queue_add(tx_queue, &ack, NETHDR_ACK_SIZ);
 	write_evfd(STATE_SYNC(evfd));
 }
@@ -315,10 +326,29 @@ static int digest_msg(const struct nethdr *net)
 	return MSG_BAD;
 }
 
+static int digest_hello(const struct nethdr *net)
+{
+	int ret = 0;
+
+	if (IS_HELLO(net)) {
+		dlog(LOG_NOTICE, "The other node says HELLO");
+		hello_state = HELLO_BACK;
+		ret = 1;
+	} else if (IS_HELLO_BACK(net)) {
+		dlog(LOG_NOTICE, "The other node says HELLO BACK");
+		hello_state = HELLO_DONE;
+	}
+
+	return ret;
+}
+
 static int ftfw_recv(const struct nethdr *net)
 {
 	int ret = MSG_DATA;
 
+	if (digest_hello(net))
+		goto bypass;
+
 	switch (mcast_track_seq(net->seq, &exp_seq)) {
 	case SEQ_AFTER:
 		ret = digest_msg(net);
@@ -348,14 +378,12 @@ static int ftfw_recv(const struct nethdr *net)
 		/* we don't accept delayed packets */
 		dlog(LOG_WARNING, "Received seq=%u before expected seq=%u",
 				   net->seq, exp_seq);
-		dlog(LOG_WARNING, "Probably the other node has come back"
-				  "to life but you forgot to add "
-				  "conntrackd -r to your scripts");
 		ret = MSG_DROP;
 		break;
 
 	case SEQ_UNSET:
 	case SEQ_IN_SYNC:
+bypass:
 		ret = digest_msg(net);
 		if (ret == MSG_BAD) {
 			ret = MSG_BAD;
@@ -390,8 +418,6 @@ static void ftfw_send(struct nethdr *net, struct us_conntrack *u)
 	struct netpld *pld = NETHDR_DATA(net);
 	struct cache_ftfw *cn;
 
-	HDR_NETWORK2HOST(net);
-
 	switch(ntohs(pld->query)) {
 	case NFCT_Q_CREATE:
 	case NFCT_Q_UPDATE:
@@ -404,7 +430,19 @@ static void ftfw_send(struct nethdr *net, struct us_conntrack *u)
 			rs_list_len--;
 		}
 
-		cn->seq = net->seq;
+		switch(hello_state) {
+		case SAY_HELLO:
+			net->flags = ntohs(net->flags) | NET_F_HELLO;
+			net->flags = htons(net->flags);
+			break;
+		case HELLO_BACK:
+			net->flags = ntohs(net->flags) | NET_F_HELLO_BACK;
+			net->flags = htons(net->flags);
+			hello_state = HELLO_DONE;
+			break;
+		}
+
+		cn->seq = ntohl(net->seq);
 		list_add_tail(&cn->rs_list, &rs_list);
 		rs_list_len++;
 		break;
diff --git a/src/sync-mode.c b/src/sync-mode.c
index 16cc70d..4b36935 100644
--- a/src/sync-mode.c
+++ b/src/sync-mode.c
@@ -395,9 +395,11 @@ static void mcast_send_sync(struct us_conntrack *u, int query)
 
 	net = BUILD_NETMSG(u->ct, query);
 	len = prepare_send_netmsg(STATE_SYNC(mcast_client), net);
-	mcast_buffered_send_netmsg(STATE_SYNC(mcast_client), net, len);
+
 	if (STATE_SYNC(sync)->send)
 		STATE_SYNC(sync)->send(net, u);
+
+	mcast_buffered_send_netmsg(STATE_SYNC(mcast_client), net, len);
 }
 
 static int purge_step(void *data1, void *data2)