netdev: Swap transmit and receive stats on internal ports.

Internal ports appear to have their transmit and receive stats swapped
because from the kernel's point of view these ports are acting like
the machine connected to the switch, not the switch itself.  This swaps
the stats for consistency with other ports.

diff --git a/lib/netdev-linux.c b/lib/netdev-linux.c
index 11d83e9..7fde7e0 100644 (file)
--- a/lib/netdev-linux.c
+++ b/lib/netdev-linux.c
@@ -85,7 +85,8 @@ enum {
     VALID_IN4 = 1 << 2,
     VALID_IN6 = 1 << 3,
     VALID_MTU = 1 << 4,
-    VALID_CARRIER = 1 << 5
+    VALID_CARRIER = 1 << 5,
+    VALID_IS_INTERNAL = 1 << 6
 };
 
 /* Cached network device information. */
@@ -100,6 +101,7 @@ struct netdev_linux_cache {
     struct in6_addr in6;
     int mtu;
     int carrier;
+    bool is_internal;
 };
 
 static struct shash cache_map = SHASH_INITIALIZER(&cache_map);
@@ -625,25 +627,81 @@ check_for_working_netlink_stats(void)
  * XXX All of the members of struct netdev_stats are 64 bits wide, but on
  * 32-bit architectures the Linux network stats are only 32 bits. */
 static int
-netdev_linux_get_stats(const struct netdev *netdev, struct netdev_stats *stats)
+netdev_linux_get_stats(const struct netdev *netdev_, struct netdev_stats *stats)
 {
+    struct netdev_linux *netdev = netdev_linux_cast(netdev_);
     static int use_netlink_stats = -1;
     int error;
+    struct netdev_stats raw_stats;
+    struct netdev_stats *collect_stats = stats;
 
     COVERAGE_INC(netdev_get_stats);
+
+    if (!(netdev->cache->valid & VALID_IS_INTERNAL)) {
+        netdev->cache->is_internal = (netdev->tap_fd != -1);
+
+        if (!netdev->cache->is_internal) {
+            struct ethtool_drvinfo drvinfo;
+
+            memset(&drvinfo, 0, sizeof drvinfo);
+            error = netdev_linux_do_ethtool(&netdev->netdev,
+                                            (struct ethtool_cmd *)&drvinfo,
+                                            ETHTOOL_GDRVINFO,
+                                            "ETHTOOL_GDRVINFO");
+
+            if (!error) {
+                netdev->cache->is_internal = !strcmp(drvinfo.driver,
+                                                     "openvswitch");
+            }
+        }
+    }
+
+    if (netdev->cache->is_internal) {
+        collect_stats = &raw_stats;
+    }
+
     if (use_netlink_stats < 0) {
         use_netlink_stats = check_for_working_netlink_stats();
     }
     if (use_netlink_stats) {
         int ifindex;
 
-        error = get_ifindex(netdev, &ifindex);
+        error = get_ifindex(&netdev->netdev, &ifindex);
         if (!error) {
-            error = get_stats_via_netlink(ifindex, stats);
+            error = get_stats_via_netlink(ifindex, collect_stats);
         }
     } else {
-        error = get_stats_via_proc(netdev->name, stats);
+        error = get_stats_via_proc(netdev->netdev.name, collect_stats);
+    }
+
+    /* If this port is an internal port then the transmit and receive stats
+     * will appear to be swapped relative to the other ports since we are the
+     * one sending the data, not a remote computer.  For consistency, we swap
+     * them back here. */
+    if (netdev->cache->is_internal) {
+        stats->rx_packets = raw_stats.tx_packets;
+        stats->tx_packets = raw_stats.rx_packets;
+        stats->rx_bytes = raw_stats.tx_bytes;
+        stats->tx_bytes = raw_stats.rx_bytes;
+        stats->rx_errors = raw_stats.tx_errors;
+        stats->tx_errors = raw_stats.rx_errors;
+        stats->rx_dropped = raw_stats.tx_dropped;
+        stats->tx_dropped = raw_stats.rx_dropped;
+        stats->multicast = raw_stats.multicast;
+        stats->collisions = raw_stats.collisions;
+        stats->rx_length_errors = 0;
+        stats->rx_over_errors = 0;
+        stats->rx_crc_errors = 0;
+        stats->rx_frame_errors = 0;
+        stats->rx_fifo_errors = 0;
+        stats->rx_missed_errors = 0;
+        stats->tx_aborted_errors = 0;
+        stats->tx_carrier_errors = 0;
+        stats->tx_fifo_errors = 0;
+        stats->tx_heartbeat_errors = 0;
+        stats->tx_window_errors = 0;
     }
+
     return error;
 }