From: Willy Tarreau <w@1wt.eu>
Date: Fri, 25 Sep 2020 17:40:31 +0000 (+0200)
Subject: MINOR: protocol: implement an ->rx_resume() method
X-Git-Tag: v2.3-dev6~29
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=58e6b71bb0a8b06276970e7c6e9c4fea2aff1b37;p=thirdparty%2Fhaproxy.git

MINOR: protocol: implement an ->rx_resume() method

This one undoes ->rx_suspend(), it tries to restore an operational socket.
It was only implemented for TCP since it's the only one we support right
now.
---

diff --git a/include/haproxy/protocol-t.h b/include/haproxy/protocol-t.h
index 75da65b468..3d5ce82cdc 100644
--- a/include/haproxy/protocol-t.h
+++ b/include/haproxy/protocol-t.h
@@ -74,8 +74,9 @@ struct proto_fam {
 
 /* This structure contains all information needed to easily handle a protocol.
  * Its primary goal is to ease listeners maintenance. Specifically, the
- * bind() primitive must be used before any fork(). rx_* may be null if the
- * protocol doesn't provide direct access to the receiver.
+ * bind() primitive must be used before any fork(). rx_suspend()/rx_resume()
+ * return >0 on success, 0 if rx stopped, -1 on failure to proceed. rx_* may
+ * be null if the protocol doesn't provide direct access to the receiver.
  */
 struct protocol {
 	char name[PROTO_NAME_LEN];			/* protocol name, zero-terminated */
@@ -91,6 +92,7 @@ struct protocol {
 
 	/* functions acting on the receiver */
 	int (*rx_suspend)(struct receiver *rx);         /* temporarily suspend this receiver for a soft restart */
+	int (*rx_resume)(struct receiver *rx);          /* try to resume a temporarily suspended receiver */
 
 	/* functions acting on connections */
 	void (*accept)(int fd);				/* generic accept function */
diff --git a/src/proto_tcp.c b/src/proto_tcp.c
index b3dbdd467d..5aa7bfd60f 100644
--- a/src/proto_tcp.c
+++ b/src/proto_tcp.c
@@ -46,6 +46,7 @@
 
 static int tcp_bind_listener(struct listener *listener, char *errmsg, int errlen);
 static int tcp_suspend_receiver(struct receiver *rx);
+static int tcp_resume_receiver(struct receiver *rx);
 static void tcpv4_add_listener(struct listener *listener, int port);
 static void tcpv6_add_listener(struct listener *listener, int port);
 
@@ -60,6 +61,7 @@ static struct protocol proto_tcpv4 = {
 	.add = tcpv4_add_listener,
 	.listen = tcp_bind_listener,
 	.rx_suspend = tcp_suspend_receiver,
+	.rx_resume = tcp_resume_receiver,
 	.accept = &listener_accept,
 	.connect = tcp_connect_server,
 	.receivers = LIST_HEAD_INIT(proto_tcpv4.receivers),
@@ -79,6 +81,7 @@ static struct protocol proto_tcpv6 = {
 	.add = tcpv6_add_listener,
 	.listen = tcp_bind_listener,
 	.rx_suspend = tcp_suspend_receiver,
+	.rx_resume = tcp_resume_receiver,
 	.accept = &listener_accept,
 	.connect = tcp_connect_server,
 	.receivers = LIST_HEAD_INIT(proto_tcpv6.receivers),
@@ -767,6 +770,23 @@ static int tcp_suspend_receiver(struct receiver *rx)
 	return -1;
 }
 
+/* Resume a receiver. Returns < 0 in case of failure, 0 if the receiver
+ * was totally stopped, or > 0 if correctly suspended.
+ */
+static int tcp_resume_receiver(struct receiver *rx)
+{
+	struct listener *l = LIST_ELEM(rx, struct listener *, rx);
+
+	if (rx->fd < 0)
+		return 0;
+
+	if (listen(rx->fd, listener_backlog(l)) == 0) {
+		fd_want_recv(l->rx.fd);
+		return 1;
+	}
+	return -1;
+}
+
 
 /*
  * Local variables: