net/tap: add link status notification

As tap is a virtual device, there's no physical way a link can be cut.
However, it has an associated kernel netdevice and possibly a remote
netdevice too. These netdevices link status may change outside of the
DPDK scope, through an external command such as:

  ip link set dev tapX down

This commit implements link status notification through netlink.

Signed-off-by: Pascal Mazon <pascal.mazon@6wind.com>
Acked-by: Keith Wiles <keith.wiles@intel.com>

diff --git a/doc/guides/nics/features/tap.ini b/doc/guides/nics/features/tap.ini
index 9d73f61..20cbeee 100644 (file)
--- a/doc/guides/nics/features/tap.ini
+++ b/doc/guides/nics/features/tap.ini
@@ -5,6 +5,7 @@
 ;
 [Features]
 Link status          = Y
+Link status event    = Y
 Jumbo frame          = Y
 Promiscuous mode     = Y
 Allmulticast mode    = Y

diff --git a/drivers/net/tap/rte_eth_tap.c b/drivers/net/tap/rte_eth_tap.c
index 54122fd..6567bba 100644 (file)
--- a/drivers/net/tap/rte_eth_tap.c
+++ b/drivers/net/tap/rte_eth_tap.c
@@ -61,6 +61,7 @@
 
 #include <rte_eth_tap.h>
 #include <tap_flow.h>
+#include <tap_netlink.h>
 #include <tap_tcmsgs.h>
 
 /* Linux based path to the TUN device */
@@ -111,6 +112,8 @@ static int
 tap_ioctl(struct pmd_internals *pmd, unsigned long request,
          struct ifreq *ifr, int set);
 
+static int tap_intr_handle_set(struct rte_eth_dev *dev, int set);
+
 /* Tun/Tap allocation routine
  *
  * name is the number of the interface to use, unless NULL to take the host
@@ -520,6 +523,11 @@ tap_link_set_up(struct rte_eth_dev *dev)
 static int
 tap_dev_start(struct rte_eth_dev *dev)
 {
+       int err;
+
+       err = tap_intr_handle_set(dev, 1);
+       if (err)
+               return err;
        return tap_link_set_up(dev);
 }
 
@@ -528,6 +536,7 @@ tap_dev_start(struct rte_eth_dev *dev)
 static void
 tap_dev_stop(struct rte_eth_dev *dev)
 {
+       tap_intr_handle_set(dev, 0);
        tap_link_set_down(dev);
 }
 
@@ -976,6 +985,55 @@ tap_set_mc_addr_list(struct rte_eth_dev *dev __rte_unused,
        return 0;
 }
 
+static int
+tap_nl_msg_handler(struct nlmsghdr *nh, void *arg)
+{
+       struct rte_eth_dev *dev = arg;
+       struct pmd_internals *pmd = dev->data->dev_private;
+       struct ifinfomsg *info = NLMSG_DATA(nh);
+
+       if (nh->nlmsg_type != RTM_NEWLINK ||
+           (info->ifi_index != pmd->if_index &&
+            info->ifi_index != pmd->remote_if_index))
+               return 0;
+       return tap_link_update(dev, 0);
+}
+
+static void
+tap_dev_intr_handler(struct rte_intr_handle *intr_handle __rte_unused,
+                    void *cb_arg)
+{
+       struct rte_eth_dev *dev = cb_arg;
+       struct pmd_internals *pmd = dev->data->dev_private;
+
+       nl_recv(pmd->intr_handle.fd, tap_nl_msg_handler, dev);
+}
+
+static int
+tap_intr_handle_set(struct rte_eth_dev *dev, int set)
+{
+       struct pmd_internals *pmd = dev->data->dev_private;
+
+       /* In any case, disable interrupt if the conf is no longer there. */
+       if (!dev->data->dev_conf.intr_conf.lsc) {
+               if (pmd->intr_handle.fd != -1)
+                       nl_final(pmd->intr_handle.fd);
+               rte_intr_callback_unregister(
+                       &pmd->intr_handle, tap_dev_intr_handler, dev);
+               return 0;
+       }
+       if (set) {
+               pmd->intr_handle.fd = nl_init(RTMGRP_LINK);
+               if (unlikely(pmd->intr_handle.fd == -1))
+                       return -EBADF;
+               return rte_intr_callback_register(
+                       &pmd->intr_handle, tap_dev_intr_handler, dev);
+       }
+       nl_final(pmd->intr_handle.fd);
+       return rte_intr_callback_unregister(&pmd->intr_handle,
+                                           tap_dev_intr_handler, dev);
+}
+
 static const uint32_t*
 tap_dev_supported_ptypes_get(struct rte_eth_dev *dev __rte_unused)
 {
@@ -1117,7 +1175,7 @@ eth_dev_tap_create(const char *name, char *tap_name, char *remote_iface)
        data->dev_private = pmd;
        data->port_id = dev->data->port_id;
        data->mtu = dev->data->mtu;
-       data->dev_flags = RTE_ETH_DEV_DETACHABLE;
+       data->dev_flags = RTE_ETH_DEV_DETACHABLE | RTE_ETH_DEV_INTR_LSC;
        data->kdrv = RTE_KDRV_NONE;
        data->drv_name = pmd_tap_drv.driver.name;
        data->numa_node = numa_node;
@@ -1133,6 +1191,9 @@ eth_dev_tap_create(const char *name, char *tap_name, char *remote_iface)
        dev->rx_pkt_burst = pmd_rx_burst;
        dev->tx_pkt_burst = pmd_tx_burst;
 
+       pmd->intr_handle.type = RTE_INTR_HANDLE_EXT;
+       pmd->intr_handle.fd = -1;
+
        /* Presetup the fds to -1 as being not valid */
        for (i = 0; i < RTE_PMD_TAP_MAX_QUEUES; i++) {
                pmd->rxq[i].fd = -1;
@@ -1147,7 +1208,7 @@ eth_dev_tap_create(const char *name, char *tap_name, char *remote_iface)
         * If no netlink socket can be created, then it will fail when
         * creating/destroying flow rules.
         */
-       pmd->nlsk_fd = nl_init();
+       pmd->nlsk_fd = nl_init(0);
        if (strlen(remote_iface)) {
                pmd->remote_if_index = if_nametoindex(remote_iface);
                snprintf(pmd->remote_iface, RTE_ETH_NAME_MAX_LEN,

diff --git a/drivers/net/tap/rte_eth_tap.h b/drivers/net/tap/rte_eth_tap.h
index a559f6b..f1496dc 100644 (file)
--- a/drivers/net/tap/rte_eth_tap.h
+++ b/drivers/net/tap/rte_eth_tap.h
@@ -90,6 +90,7 @@ struct pmd_internals {
        LIST_HEAD(tap_implicit_flows, rte_flow) implicit_flows;
        struct rx_queue rxq[RTE_PMD_TAP_MAX_QUEUES]; /* List of RX queues */
        struct tx_queue txq[RTE_PMD_TAP_MAX_QUEUES]; /* List of TX queues */
+       struct rte_intr_handle intr_handle;          /* LSC interrupt handle. */
 };
 
 #endif /* _RTE_ETH_TAP_H_ */

diff --git a/drivers/net/tap/tap_netlink.c b/drivers/net/tap/tap_netlink.c
index 9710e41..6de896a 100644 (file)
--- a/drivers/net/tap/tap_netlink.c
+++ b/drivers/net/tap/tap_netlink.c
@@ -55,14 +55,21 @@ struct nested_tail {
 /**
  * Initialize a netlink socket for communicating with the kernel.
  *
+ * @param nl_groups
+ *   Set it to a netlink group value (e.g. RTMGRP_LINK) to receive messages for
+ *   specific netlink multicast groups. Otherwise, no subscription will be made.
+ *
  * @return
  *   netlink socket file descriptor on success, -1 otherwise.
  */
 int
-nl_init(void)
+nl_init(uint32_t nl_groups)
 {
        int fd, sndbuf_size = SNDBUF_SIZE, rcvbuf_size = RCVBUF_SIZE;
-       struct sockaddr_nl local = { .nl_family = AF_NETLINK };
+       struct sockaddr_nl local = {
+               .nl_family = AF_NETLINK,
+               .nl_groups = nl_groups,
+       };
 
        fd = socket(AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, NETLINK_ROUTE);
        if (fd < 0) {

diff --git a/drivers/net/tap/tap_netlink.h b/drivers/net/tap/tap_netlink.h
index 52ba8c0..98e1390 100644 (file)
--- a/drivers/net/tap/tap_netlink.h
+++ b/drivers/net/tap/tap_netlink.h
@@ -53,7 +53,7 @@ struct nlmsg {
 
 #define NLMSG_TAIL(nlh) (void *)((char *)(nlh) + NLMSG_ALIGN((nlh)->nlmsg_len))
 
-int nl_init(void);
+int nl_init(uint32_t nl_groups);
 int nl_final(int nlsk_fd);
 int nl_send(int nlsk_fd, struct nlmsghdr *nh);
 int nl_recv(int nlsk_fd, int (*callback)(struct nlmsghdr *, void *), void *arg);

diff --git a/drivers/net/tap/tap_tcmsgs.c b/drivers/net/tap/tap_tcmsgs.c
index 9a146d1..af1c9ae 100644 (file)
--- a/drivers/net/tap/tap_tcmsgs.c
+++ b/drivers/net/tap/tap_tcmsgs.c
@@ -107,7 +107,7 @@ qdisc_del(int nlsk_fd, uint16_t ifindex, struct qdisc *qinfo)
        msg.t.tcm_parent = qinfo->parent;
        /* if no netlink socket is provided, create one */
        if (!nlsk_fd) {
-               fd = nl_init();
+               fd = nl_init(0);
                if (fd < 0) {
                        RTE_LOG(ERR, PMD,
                                "Could not delete QDISC: null netlink socket\n");