MEDIUM: listener: implement a per-protocol pause() function

In order to fix the abstact socket pause mechanism during soft restarts,
we'll need to proceed differently depending on the socket protocol. The
pause_listener() function already supports some protocol-specific handling
for the TCP case.

This commit makes this cleaner by adding a new ->pause() function to the
protocol struct, which, if defined, may be used to pause a listener of a
given protocol.

For now, only TCP has been adapted, with the specific code moved from
pause_listener() to tcp_pause_listener().
This commit is contained in:
Willy Tarreau 2014-07-07 20:22:12 +02:00
parent 3c5efa2b32
commit 092d865c53
4 changed files with 29 additions and 8 deletions

View File

@ -30,6 +30,7 @@
int tcp_bind_socket(int fd, int flags, struct sockaddr_storage *local, struct sockaddr_storage *remote);
void tcpv4_add_listener(struct listener *listener);
void tcpv6_add_listener(struct listener *listener);
int tcp_pause_listener(struct listener *l);
int tcp_connect_server(struct connection *conn, int data, int delack);
int tcp_connect_probe(struct connection *conn);
int tcp_get_src(int fd, struct sockaddr *sa, socklen_t salen, int dir);

View File

@ -60,6 +60,7 @@ struct protocol {
int (*get_src)(int fd, struct sockaddr *, socklen_t, int dir); /* syscall used to retrieve src addr */
int (*get_dst)(int fd, struct sockaddr *, socklen_t, int dir); /* syscall used to retrieve dst addr */
int (*drain)(int fd); /* indicates whether we can safely close the fd */
int (*pause)(struct listener *l); /* temporarily pause this listener for a soft restart */
struct list listeners; /* list of listeners using this protocol */
int nb_listeners; /* number of listeners */

View File

@ -95,15 +95,16 @@ int pause_listener(struct listener *l)
if (l->state <= LI_PAUSED)
return 1;
if (l->proto->sock_prot == IPPROTO_TCP) {
if (shutdown(l->fd, SHUT_WR) != 0)
return 0; /* Solaris dies here */
if (l->proto->pause) {
/* Returns < 0 in case of failure, 0 if the listener
* was totally stopped, or > 0 if correctly paused.
*/
int ret = l->proto->pause(l);
if (listen(l->fd, l->backlog ? l->backlog : l->maxconn) != 0)
return 0; /* OpenBSD dies here */
if (shutdown(l->fd, SHUT_RD) != 0)
return 0; /* should always be OK */
if (ret < 0)
return 0;
else if (ret == 0)
return 1;
}
if (l->state == LI_LIMITED)

View File

@ -80,6 +80,7 @@ static struct protocol proto_tcpv4 = {
.get_src = tcp_get_src,
.get_dst = tcp_get_dst,
.drain = tcp_drain,
.pause = tcp_pause_listener,
.listeners = LIST_HEAD_INIT(proto_tcpv4.listeners),
.nb_listeners = 0,
};
@ -102,6 +103,7 @@ static struct protocol proto_tcpv6 = {
.get_src = tcp_get_src,
.get_dst = tcp_get_dst,
.drain = tcp_drain,
.pause = tcp_pause_listener,
.listeners = LIST_HEAD_INIT(proto_tcpv6.listeners),
.nb_listeners = 0,
};
@ -947,6 +949,22 @@ void tcpv6_add_listener(struct listener *listener)
proto_tcpv6.nb_listeners++;
}
/* Pause a listener. Returns < 0 in case of failure, 0 if the listener
* was totally stopped, or > 0 if correctly paused.
*/
int tcp_pause_listener(struct listener *l)
{
if (shutdown(l->fd, SHUT_WR) != 0)
return -1; /* Solaris dies here */
if (listen(l->fd, l->backlog ? l->backlog : l->maxconn) != 0)
return -1; /* OpenBSD dies here */
if (shutdown(l->fd, SHUT_RD) != 0)
return -1; /* should always be OK */
return 1;
}
/* This function performs the TCP request analysis on the current request. It
* returns 1 if the processing can continue on next analysers, or zero if it
* needs more data, encounters an error, or wants to immediately abort the