[ovs-dev] [PATCH 5/8] netdev-linux: use netlink to update netdev.

[Flavio Leitner]

The ioctl interface doesn't support network namespaces, so
try updating the netdev using netlink message instead.

To provide backwards compatibility, fall back to the previous
method if netlink isn't supported or fails.

Signed-off-by: Flavio Leitner <fbl at redhat.com>
---
 lib/netdev-linux.c | 107 +++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 104 insertions(+), 3 deletions(-)

diff --git a/lib/netdev-linux.c b/lib/netdev-linux.c
index 7f9387c0e..0250b0987 100644
--- a/lib/netdev-linux.c
+++ b/lib/netdev-linux.c
@@ -86,6 +86,9 @@ COVERAGE_DEFINE(netdev_get_ethtool);
 COVERAGE_DEFINE(netdev_set_ethtool);
 
 
+#ifndef IFLA_IF_NETNSID
+#define IFLA_IF_NETNSID 0x45
+#endif
 /* These were introduced in Linux 2.6.14, so they might be missing if we have
  * old headers. */
 #ifndef ADVERTISED_Pause
@@ -615,6 +618,7 @@ netdev_linux_netns_is_eq(struct netdev_linux *netdev, struct netns *ns)
     return netns_eq(&netdev->netns, ns);
 }
 
+static int netdev_linux_update_via_netlink(struct netdev_linux *);
 static void netdev_linux_update(struct netdev_linux *netdev, struct netns *,
                                 const struct rtnetlink_change *)
     OVS_REQUIRES(netdev->mutex);
@@ -1435,6 +1439,11 @@ netdev_linux_get_etheraddr(const struct netdev *netdev_, struct eth_addr *mac)
 
     ovs_mutex_lock(&netdev->mutex);
     if (!(netdev->cache_valid & VALID_ETHERADDR)) {
+        netdev_linux_update_via_netlink(netdev);
+    }
+
+    if (!(netdev->cache_valid & VALID_ETHERADDR)) {
+        /* Fall back to ioctl if netlink fails */
         netdev->ether_addr_error = get_etheraddr(netdev_get_name(netdev_),
                                                  &netdev->etheraddr);
         netdev->cache_valid |= VALID_ETHERADDR;
@@ -1455,6 +1464,11 @@ netdev_linux_get_mtu__(struct netdev_linux *netdev, int *mtup)
     int error;
 
     if (!(netdev->cache_valid & VALID_MTU)) {
+        netdev_linux_update_via_netlink(netdev);
+    }
+
+    if (!(netdev->cache_valid & VALID_MTU)) {
+        /* Fall back to ioctl if netlink fails */
         struct ifreq ifr;
 
         netdev->netdev_mtu_error = af_inet_ifreq_ioctl(
@@ -2867,12 +2881,21 @@ netdev_linux_update_flags(struct netdev *netdev_, enum netdev_flags off,
                           enum netdev_flags on, enum netdev_flags *old_flagsp)
 {
     struct netdev_linux *netdev = netdev_linux_cast(netdev_);
-    int error;
+    int error = 0;
 
     ovs_mutex_lock(&netdev->mutex);
-    error = update_flags(netdev, off, on, old_flagsp);
+    if (on || off) {
+        /* Changing flags over netlink isn't support yet. */
+        error = update_flags(netdev, off, on, old_flagsp);
+    } else {
+        /* Try reading flags over netlink, or fall back to ioctl. */
+        if (!netdev_linux_update_via_netlink(netdev)) {
+            *old_flagsp = iff_to_nd_flags(netdev->ifi_flags);
+        } else {
+            error = update_flags(netdev, off, on, old_flagsp);
+        }
+    }
     ovs_mutex_unlock(&netdev->mutex);
-
     return error;
 }
 
@@ -5515,6 +5538,11 @@ get_ifindex(const struct netdev *netdev_, int *ifindexp)
     struct netdev_linux *netdev = netdev_linux_cast(netdev_);
 
     if (!(netdev->cache_valid & VALID_IFINDEX)) {
+        netdev_linux_update_via_netlink(netdev);
+    }
+
+    if (!(netdev->cache_valid & VALID_IFINDEX)) {
+        /* Fall back to ioctl if netlink fails */
         int ifindex = linux_get_ifindex(netdev_get_name(netdev_));
 
         if (ifindex < 0) {
@@ -5532,6 +5560,79 @@ get_ifindex(const struct netdev *netdev_, int *ifindexp)
 }
 
 static int
+netdev_linux_update_via_netlink(struct netdev_linux *netdev)
+{
+    struct ofpbuf request;
+    struct ofpbuf *reply;
+    struct rtnetlink_change chg;
+    struct rtnetlink_change *change = &chg;
+    int error;
+
+    ofpbuf_init(&request, 0);
+    nl_msg_put_nlmsghdr(&request,
+                        sizeof(struct ifinfomsg) + NL_ATTR_SIZE(IFNAMSIZ),
+                        RTM_GETLINK, NLM_F_REQUEST);
+    ofpbuf_put_zeros(&request, sizeof(struct ifinfomsg));
+
+    /* The correct identifiers for a Linux device are netnsid and ifindex,
+     * but ifindex changes as the port is moved to another network namespace
+     * and the interface name statically stored in ovsdb. */
+    nl_msg_put_string(&request, IFLA_IFNAME, netdev_get_name(&netdev->up));
+    if (netdev_linux_netns_is_remote(netdev)) {
+        nl_msg_push_u32(&request, IFLA_IF_NETNSID, netdev->netns.id);
+    }
+    error = nl_transact(NETLINK_ROUTE, &request, &reply);
+    ofpbuf_uninit(&request);
+    if (error) {
+        ofpbuf_delete(reply);
+        return error;
+    }
+
+    if (rtnetlink_parse(reply, change)
+        && change->nlmsg_type == RTM_NEWLINK) {
+        bool changed = false;
+        error = 0;
+
+        /* Update netdev from rtnl msg and increment its seq if needed. */
+        if ((change->ifi_flags ^ netdev->ifi_flags) & IFF_RUNNING) {
+            netdev->carrier_resets++;
+            changed = true;
+        }
+        if (change->ifi_flags != netdev->ifi_flags) {
+            netdev->ifi_flags = change->ifi_flags;
+            changed = true;
+        }
+        if (change->mtu && change->mtu != netdev->mtu) {
+            netdev->mtu = change->mtu;
+            netdev->cache_valid |= VALID_MTU;
+            netdev->netdev_mtu_error = 0;
+            changed = true;
+        }
+        if (!eth_addr_is_zero(change->mac)
+            && !eth_addr_equals(change->mac, netdev->etheraddr)) {
+            netdev->etheraddr = change->mac;
+            netdev->cache_valid |= VALID_ETHERADDR;
+            netdev->ether_addr_error = 0;
+            changed = true;
+        }
+        if (change->if_index != netdev->ifindex) {
+            netdev->ifindex = change->if_index;
+            netdev->cache_valid |= VALID_IFINDEX;
+            netdev->get_ifindex_error = 0;
+            changed = true;
+        }
+        if (changed) {
+            netdev_change_seq_changed(&netdev->up);
+        }
+    } else {
+        error = EINVAL;
+    }
+
+    ofpbuf_delete(reply);
+    return error;
+}
+
+static int
 get_etheraddr(const char *netdev_name, struct eth_addr *ea)
 {
     struct ifreq ifr;
-- 
2.13.6