[UNIKRAFT/LIBLWIP PATCH v3 13/16] plat/tap: Start a tap device

[Sharan Santhanam <sharan.santhanam@xxxxxxxxx>]

The patch implements the function to start the tap device

Signed-off-by: Sharan Santhanam <sharan.santhanam@xxxxxxxxx>
---
 plat/drivers/tap/tap.c | 21 +++++++++++++++++++--
 plat/linuxu/tap_io.c   | 12 ++++++++++++
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/plat/drivers/tap/tap.c b/plat/drivers/tap/tap.c
index 2667fd10..b7037b64 100644
--- a/plat/drivers/tap/tap.c
+++ b/plat/drivers/tap/tap.c
@@ -430,10 +430,27 @@ err_exit:
 
 static int tap_netdev_start(struct uk_netdev *n)
 {
-       int rc = -EINVAL;
+       int rc = 0;
+       struct tap_net_dev *tdev = NULL;
+       struct uk_ifreq ifrq = {0};
 
        UK_ASSERT(n);
-       return rc;
+       tdev = to_tapnetdev(n);
+       /* Set the name of the device */
+       snprintf(ifrq.ifr_name, sizeof(ifrq.ifr_name), "%s", tdev->name);
+
+       ifrq.ifr_flags = UK_IFF_UP | UK_IFF_PROMISC;
+
+       /* Set the status of the device */
+       rc = tap_netif_configure(tdev->ctrl_sock, UK_SIOCSIFFLAGS, &ifrq);
+       if (rc < 0) {
+               uk_pr_err(DRIVER_NAME": Failed(%d) to set the flags of if: 
%s\n",
+                         rc, tdev->name);
+               return rc;
+       }
+       tdev->promisc = 1;
+
+       return 0;
 }
 
 static void tap_netdev_info_get(struct uk_netdev *dev __unused,
diff --git a/plat/linuxu/tap_io.c b/plat/linuxu/tap_io.c
index 4828639d..8c44281c 100644
--- a/plat/linuxu/tap_io.c
+++ b/plat/linuxu/tap_io.c
@@ -64,8 +64,20 @@ int tap_netif_configure(int fd, __u32 request, void *arg)
 {
        int rc;
        struct uk_ifreq *usr_ifr = (struct uk_ifreq *) arg;
+       struct uk_ifreq ifr = {0};
 
        switch (request) {
+       case UK_SIOCSIFFLAGS:
+               snprintf(ifr.ifr_name, IFNAMSIZ, "%s", usr_ifr->ifr_name);
+               rc = sys_ioctl(fd, UK_SIOCGIFFLAGS, &ifr);
+               /* fetch current flags to leave other flags untouched */
+               if (rc < 0) {
+                       uk_pr_err("Failed to read flags %d\n", rc);
+                       goto exit_error;
+               }
+               usr_ifr->ifr_flags |= ifr.ifr_flags;
+               break;
+       case UK_SIOCGIFFLAGS:
        case UK_SIOCGIFINDEX:
        case UK_SIOCGIFHWADDR:
        case UK_SIOCSIFHWADDR:
-- 
2.20.1