interfaces: use ethtool to get permanent MAC for bonds/teams

As this doesn't work for all devices (like dummy and veth), we still
fallback to old code using /proc/net/bonding for bonds. No fallback
available for team devices.

diff --git a/NEWS b/NEWS
index 61f917a65f576534d0cd87cccda8d5f7401048d6..11764521ea60d433ca85308f9b7186b63ee6c98f 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -1,6 +1,9 @@
 lldpd (0.9.8)
   * Changes:
     + "Station" capability is only set if no other bit is set.
+    + Use ethtool to get permanent address for bonds and teams. This
+      might provide different results than the previous method. Some
+      devices may still use the previous method.
   * Fixes:
     + Handle team interfaces like a bond. Real MAC address cannot be
       retrieved yet.

diff --git a/src/daemon/interfaces-linux.c b/src/daemon/interfaces-linux.c
index 3150e6b888f59002f7826f20089e6fc5b14e665c..ea7d6221509774e6b0cc5c7837081f273749304b 100644 (file)
--- a/src/daemon/interfaces-linux.c
+++ b/src/daemon/interfaces-linux.c
@@ -277,12 +277,64 @@ iflinux_is_bond(struct lldpd *cfg,
        return 0;
 }
 
+/**
+ * Get permanent MAC from ethtool.
+ *
+ * Return 0 on success, -1 on error.
+ */
+static int
+iflinux_get_permanent_mac_ethtool(struct lldpd *cfg,
+    struct interfaces_device_list *interfaces,
+    struct interfaces_device *iface)
+{
+       struct ifreq ifr = {};
+       union {
+               struct ethtool_perm_addr addr;
+               /* cppcheck-suppress unusedStructMember */
+               char u8[sizeof(struct ethtool_perm_addr) + ETHER_ADDR_LEN];
+       } epaddr;
+
+       strlcpy(ifr.ifr_name, iface->name, sizeof(ifr.ifr_name));
+       epaddr.addr.cmd = ETHTOOL_GPERMADDR;
+       epaddr.addr.size = ETHER_ADDR_LEN;
+       ifr.ifr_data = (caddr_t)&epaddr.addr;
+       if (ioctl(cfg->g_sock, SIOCETHTOOL, &ifr) == -1) {
+               static int once = 0;
+               if (errno == EPERM && !once) {
+                       log_warn("interfaces",
+                           "no permission to get permanent MAC address for %s (requires 2.6.19+)",
+                           iface->name);
+                       once = 1;
+                       return -1;
+               }
+               if (errno != EPERM)
+                       log_warnx("interfaces", "cannot get permanent MAC address for %s",
+                           iface->name);
+               return -1;
+       }
+       if (epaddr.addr.data[0] != 0 ||
+           epaddr.addr.data[1] != 0 ||
+           epaddr.addr.data[2] != 0 ||
+           epaddr.addr.data[3] != 0 ||
+           epaddr.addr.data[4] != 0 ||
+           epaddr.addr.data[5] != 0 ||
+           epaddr.addr.data[6] != 0) {
+               memcpy(iface->address, epaddr.addr.data, ETHER_ADDR_LEN);
+               return 0;
+       }
+       log_debug("interfaces", "cannot get permanent MAC for %s", iface->name);
+       return -1;
+}
+
+/**
+ * Get permanent MAC address for a bond device.
+ */
 static void
-iflinux_get_permanent_mac(struct lldpd *cfg,
+iflinux_get_permanent_mac_bond(struct lldpd *cfg,
     struct interfaces_device_list *interfaces,
     struct interfaces_device *iface)
 {
-       struct interfaces_device *master;
+       struct interfaces_device *master = iface->upper;
        int f, state = 0;
        FILE *netbond;
        const char *slaveif = "Slave Interface: ";
@@ -291,12 +343,6 @@ iflinux_get_permanent_mac(struct lldpd *cfg,
        char path[SYSFS_PATH_MAX];
        char line[100];
 
-       if ((master = iface->upper) == NULL || master->type != IFACE_BOND_T)
-               return;
-       if (master->driver == NULL || strcmp(master->driver, "bonding"))
-               /* Not a bond interface, maybe a team */
-               return;
-
        /* We have a bond, we need to query it to get real MAC addresses */
        if (snprintf(path, SYSFS_PATH_MAX, "/proc/net/bonding/%s",
                master->name) >= SYSFS_PATH_MAX) {
@@ -314,7 +360,7 @@ iflinux_get_permanent_mac(struct lldpd *cfg,
        if (f < 0) {
                log_warnx("interfaces",
                    "unable to get permanent MAC address for %s",
-                   master->name);
+                   iface->name);
                return;
        }
        if ((netbond = fdopen(f, "r")) == NULL) {
@@ -362,11 +408,29 @@ iflinux_get_permanent_mac(struct lldpd *cfg,
                        break;
                }
        }
-       log_warnx("interfaces", "unable to find real mac address for %s",
+       log_warnx("interfaces", "unable to find real MAC address for enslaved %s",
            iface->name);
        fclose(netbond);
 }
 
+/**
+ * Get permanent MAC.
+ */
+static void
+iflinux_get_permanent_mac(struct lldpd *cfg,
+    struct interfaces_device_list *interfaces,
+    struct interfaces_device *iface)
+{
+       struct interfaces_device *master = iface->upper;
+
+       if (master == NULL || master->type != IFACE_BOND_T)
+               return;
+       if (iflinux_get_permanent_mac_ethtool(cfg, interfaces, iface) == -1 &&
+           (master->driver == NULL || !strcmp(master->driver, "bonding")))
+               /* Fallback to old method for a bond */
+               iflinux_get_permanent_mac_bond(cfg, interfaces, iface);
+}
+
 static inline int
 iflinux_ethtool_link_mode_test_bit(unsigned int nr, const uint32_t *mask)
 {