net/tap: add MTU management

The MTU is assigned to the tap netdevice according to the argument, but
packet transmission and reception just write/read on an fd with the
default limit being the socket buffer size.

As a new rte_eth_dev_data is allocated during tap device init, ensure it
is set again dev->data->mtu.
Once the actual netdevice is created via tun_alloc(), make sure to apply
the desired MTU to the netdevice.

Signed-off-by: Pascal Mazon <pascal.mazon@6wind.com>
Reviewed-by: Ferruh Yigit <ferruh.yigit@intel.com>

diff --git a/doc/guides/nics/features/tap.ini b/doc/guides/nics/features/tap.ini
index d9b47a0..b805777 100644 (file)
--- a/doc/guides/nics/features/tap.ini
+++ b/doc/guides/nics/features/tap.ini
@@ -9,6 +9,7 @@ Jumbo frame          = Y
 Promiscuous mode     = Y
 Allmulticast mode    = Y
 Basic stats          = Y
+MTU update           = Y
 Unicast MAC filter   = Y
 Other kdrv           = Y
 ARMv7                = Y

diff --git a/drivers/net/tap/rte_eth_tap.c b/drivers/net/tap/rte_eth_tap.c
index 2cf8203..b14bbab 100644 (file)
--- a/drivers/net/tap/rte_eth_tap.c
+++ b/drivers/net/tap/rte_eth_tap.c
@@ -350,6 +350,7 @@ tap_ioctl(struct pmd_internals *pmd, unsigned long request,
                break;
        case SIOCGIFHWADDR:
        case SIOCSIFHWADDR:
+       case SIOCSIFMTU:
                break;
        default:
                RTE_LOG(WARNING, PMD, "%s: ioctl() called with wrong arg\n",
@@ -595,6 +596,15 @@ tap_setup_queue(struct rte_eth_dev *dev,
                                        pmd->name, qid);
                                return -1;
                        }
+                       if (qid == 0) {
+                               struct ifreq ifr;
+
+                               ifr.ifr_mtu = dev->data->mtu;
+                               if (tap_ioctl(pmd, SIOCSIFMTU, &ifr, 1) < 0) {
+                                       close(fd);
+                                       return -1;
+                               }
+                       }
                }
        }
 
@@ -691,6 +701,20 @@ tap_tx_queue_setup(struct rte_eth_dev *dev,
        return 0;
 }
 
+static int
+tap_mtu_set(struct rte_eth_dev *dev, uint16_t mtu)
+{
+       struct pmd_internals *pmd = dev->data->dev_private;
+       struct ifreq ifr = { .ifr_mtu = mtu };
+       int err = 0;
+
+       err = tap_ioctl(pmd, SIOCSIFMTU, &ifr, 1);
+       if (!err)
+               dev->data->mtu = mtu;
+
+       return err;
+}
+
 static const struct eth_dev_ops ops = {
        .dev_start              = tap_dev_start,
        .dev_stop               = tap_dev_stop,
@@ -709,6 +733,7 @@ static const struct eth_dev_ops ops = {
        .allmulticast_enable    = tap_allmulti_enable,
        .allmulticast_disable   = tap_allmulti_disable,
        .mac_addr_set           = tap_mac_set,
+       .mtu_set                = tap_mtu_set,
        .stats_get              = tap_stats_get,
        .stats_reset            = tap_stats_reset,
 };
@@ -759,6 +784,7 @@ eth_dev_tap_create(const char *name, char *tap_name)
        /* Setup some default values */
        data->dev_private = pmd;
        data->port_id = dev->data->port_id;
+       data->mtu = dev->data->mtu;
        data->dev_flags = RTE_ETH_DEV_DETACHABLE;
        data->kdrv = RTE_KDRV_NONE;
        data->drv_name = pmd_tap_drv.driver.name;