[dpdk-dev] [PATCH] net/tap: restore state of remote device when stopping

[Thomas Monjalon <thomas@monjalon.net>]

When exiting a DPDK application, the TAP remote was left
with the link down even if it was initially up.

The device flags of the remote netdevice are saved when probing,
and restored when calling the stop function.

Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
---
 drivers/net/tap/rte_eth_tap.c | 18 +++++++++++++++++-
 drivers/net/tap/rte_eth_tap.h |  2 ++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/net/tap/rte_eth_tap.c b/drivers/net/tap/rte_eth_tap.c
index 7cfa0a85d..5128152ee 100644
--- a/drivers/net/tap/rte_eth_tap.c
+++ b/drivers/net/tap/rte_eth_tap.c
@@ -565,11 +565,22 @@ tap_ioctl(struct pmd_internals *pmd, unsigned long request,
 static int
 tap_link_set_down(struct rte_eth_dev *dev)
 {
+	int err, remote_err;
 	struct pmd_internals *pmd = dev->data->dev_private;
 	struct ifreq ifr = { .ifr_flags = IFF_UP };
 
 	dev->data->dev_link.link_status = ETH_LINK_DOWN;
-	return tap_ioctl(pmd, SIOCSIFFLAGS, &ifr, 0, LOCAL_AND_REMOTE);
+	err = tap_ioctl(pmd, SIOCSIFFLAGS, &ifr, 0, LOCAL_ONLY);
+
+	if (pmd->remote_if_index) {
+		/* Restore initial remote state */
+		remote_err = ioctl(pmd->ioctl_sock, SIOCSIFFLAGS,
+				&pmd->remote_initial_ifr);
+		if (remote_err < 0)
+			err = -1;
+	}
+
+	return err;
 }
 
 static int
@@ -1320,6 +1331,11 @@ eth_dev_tap_create(struct rte_vdev_device *vdev, char *tap_name,
 		}
 		snprintf(pmd->remote_iface, RTE_ETH_NAME_MAX_LEN,
 			 "%s", remote_iface);
+
+		/* Save state of remote device */
+		tap_ioctl(pmd, SIOCGIFFLAGS, &pmd->remote_initial_ifr, 0, REMOTE_ONLY);
+
+		/* Replicate remote MAC address */
 		if (tap_ioctl(pmd, SIOCGIFHWADDR, &ifr, 0, REMOTE_ONLY) < 0) {
 			RTE_LOG(ERR, PMD, "%s: failed to get %s MAC address.",
 				pmd->name, pmd->remote_iface);
diff --git a/drivers/net/tap/rte_eth_tap.h b/drivers/net/tap/rte_eth_tap.h
index ad497b3d1..08a72d279 100644
--- a/drivers/net/tap/rte_eth_tap.h
+++ b/drivers/net/tap/rte_eth_tap.h
@@ -37,6 +37,7 @@
 #include <sys/queue.h>
 #include <sys/uio.h>
 #include <inttypes.h>
+#include <net/if.h>
 
 #include <linux/if_tun.h>
 
@@ -83,6 +84,7 @@ struct pmd_internals {
 	char name[RTE_ETH_NAME_MAX_LEN];  /* Internal Tap device name */
 	uint16_t nb_queues;               /* Number of queues supported */
 	struct ether_addr eth_addr;       /* Mac address of the device port */
+	struct ifreq remote_initial_ifr;  /* remote netdevice flags on init */
 	int remote_if_index;              /* remote netdevice IF_INDEX */
 	int if_index;                     /* IF_INDEX for the port */
 	int ioctl_sock;                   /* socket for ioctl calls */
-- 
2.13.1