[retry] Hold reference while timer is running and during expiry callback

Guarantee that a retry timer cannot go out of scope while the timer is
running, and provide a guarantee to the expiry callback that the timer
will remain in scope during the entire callback (similar to the
guarantee provided to interface methods).

Signed-off-by: Michael Brown <mcb30@ipxe.org>

4 files changed, 8 insertions, 6 deletions

diff --git a/src/net/udp/dhcp.c b/src/net/udp/dhcp.c
index 77d46545..1169abaa 100644
--- a/src/net/udp/dhcp.c
+++ b/src/net/udp/dhcp.c
@@ -1425,7 +1425,7 @@ int start_dhcp ( struct interface *job, struct net_device *netdev ) {
 	ref_init ( &dhcp->refcnt, dhcp_free );
 	intf_init ( &dhcp->job, &dhcp_job_desc, &dhcp->refcnt );
 	intf_init ( &dhcp->xfer, &dhcp_xfer_desc, &dhcp->refcnt );
-	timer_init ( &dhcp->timer, dhcp_timer_expired );
+	timer_init ( &dhcp->timer, dhcp_timer_expired, &dhcp->refcnt );
 	dhcp->netdev = netdev_get ( netdev );
 	dhcp->local.sin_family = AF_INET;
 	dhcp->local.sin_port = htons ( BOOTPC_PORT );
@@ -1528,7 +1528,7 @@ int start_pxebs ( struct interface *job, struct net_device *netdev,
 	ref_init ( &dhcp->refcnt, dhcp_free );
 	intf_init ( &dhcp->job, &dhcp_job_desc, &dhcp->refcnt );
 	intf_init ( &dhcp->xfer, &dhcp_xfer_desc, &dhcp->refcnt );
-	timer_init ( &dhcp->timer, dhcp_timer_expired );
+	timer_init ( &dhcp->timer, dhcp_timer_expired, &dhcp->refcnt );
 	dhcp->netdev = netdev_get ( netdev );
 	dhcp->local.sin_family = AF_INET;
 	fetch_ipv4_setting ( netdev_settings ( netdev ), &ip_setting,
diff --git a/src/net/udp/dns.c b/src/net/udp/dns.c
index 8283e6fb..ddbccc32 100644
--- a/src/net/udp/dns.c
+++ b/src/net/udp/dns.c
@@ -527,7 +527,7 @@ static int dns_resolv ( struct interface *resolv,
 	ref_init ( &dns->refcnt, NULL );
 	intf_init ( &dns->resolv, &dns_resolv_desc, &dns->refcnt );
 	intf_init ( &dns->socket, &dns_socket_desc, &dns->refcnt );
-	timer_init ( &dns->timer, dns_timer_expired );
+	timer_init ( &dns->timer, dns_timer_expired, &dns->refcnt );
 	memcpy ( &dns->sa, sa, sizeof ( dns->sa ) );
 
 	/* Create query */
diff --git a/src/net/udp/slam.c b/src/net/udp/slam.c
index 026bc179..0de138cd 100644
--- a/src/net/udp/slam.c
+++ b/src/net/udp/slam.c
@@ -695,8 +695,10 @@ static int slam_open ( struct interface *xfer, struct uri *uri ) {
 	intf_init ( &slam->xfer, &slam_xfer_desc, &slam->refcnt );
 	intf_init ( &slam->socket, &slam_socket_desc, &slam->refcnt );
 	intf_init ( &slam->mc_socket, &slam_mc_socket_desc, &slam->refcnt );
-	timer_init ( &slam->master_timer, slam_master_timer_expired );
-	timer_init ( &slam->slave_timer, slam_slave_timer_expired );
+	timer_init ( &slam->master_timer, slam_master_timer_expired,
+		     &slam->refcnt );
+	timer_init ( &slam->slave_timer, slam_slave_timer_expired,
+		     &slam->refcnt );
 	/* Fake an invalid cached header of { 0x00, ... } */
 	slam->header_len = 1;
 	/* Fake parameters for initial NACK */
diff --git a/src/net/udp/tftp.c b/src/net/udp/tftp.c
index e8223c99..777632ef 100644
--- a/src/net/udp/tftp.c
+++ b/src/net/udp/tftp.c
@@ -1097,7 +1097,7 @@ static int tftp_core_open ( struct interface *xfer, struct uri *uri,
 	intf_init ( &tftp->xfer, &tftp_xfer_desc, &tftp->refcnt );
 	intf_init ( &tftp->socket, &tftp_socket_desc, &tftp->refcnt );
 	intf_init ( &tftp->mc_socket, &tftp_mc_socket_desc, &tftp->refcnt );
-	timer_init ( &tftp->timer, tftp_timer_expired );
+	timer_init ( &tftp->timer, tftp_timer_expired, &tftp->refcnt );
 	tftp->uri = uri_get ( uri );
 	tftp->blksize = TFTP_DEFAULT_BLKSIZE;
 	tftp->flags = flags;