system-linux: add a function to clear bridge membership of a device and bring down...

diff --git a/system-linux.c b/system-linux.c
index db809bb4f91b7495cc9ea22057f334ea136bffa5..9a55d7410785fb9be2fd8e348eb30bede75bc5b1 100644 (file)
--- a/system-linux.c
+++ b/system-linux.c
@@ -1,12 +1,15 @@
 #include <sys/socket.h>
 #include <sys/ioctl.h>
+#include <sys/stat.h>
 
 #include <linux/rtnetlink.h>
 #include <linux/sockios.h>
 #include <linux/if_vlan.h>
 
+#include <unistd.h>
 #include <string.h>
 #include <fcntl.h>
+#include <glob.h>
 
 #include <netlink/msg.h>
 #include <netlink/attr.h>
@@ -113,87 +116,153 @@ static int system_rtnl_call(struct nl_msg *msg)
        return s;
 }
 
-int system_bridge_addbr(struct device *bridge)
-{
-       return ioctl(sock_ioctl, SIOCBRADDBR, bridge->ifname);
-}
-
 int system_bridge_delbr(struct device *bridge)
 {
        return ioctl(sock_ioctl, SIOCBRDELBR, bridge->ifname);
 }
 
-static int system_bridge_if(struct device *bridge, struct device *dev, int cmd)
+static int system_bridge_if(const char *bridge, struct device *dev, int cmd)
 {
        struct ifreq ifr;
        ifr.ifr_ifindex = dev->ifindex;
-       strncpy(ifr.ifr_name, bridge->ifname, sizeof(ifr.ifr_name));
+       strncpy(ifr.ifr_name, bridge, sizeof(ifr.ifr_name));
        return ioctl(sock_ioctl, cmd, &ifr);
 }
 
 int system_bridge_addif(struct device *bridge, struct device *dev)
 {
-       return system_bridge_if(bridge, dev, SIOCBRADDIF);
+       return system_bridge_if(bridge->ifname, dev, SIOCBRADDIF);
 }
 
 int system_bridge_delif(struct device *bridge, struct device *dev)
 {
-       return system_bridge_if(bridge, dev, SIOCBRDELIF);
+       return system_bridge_if(bridge->ifname, dev, SIOCBRDELIF);
 }
 
-static int system_vlan(struct device *dev, int id)
+static bool system_is_bridge(const char *name, char *buf, int buflen)
 {
-       struct vlan_ioctl_args ifr = {
-               .cmd = (id == 0) ? DEL_VLAN_CMD : ADD_VLAN_CMD,
-               .u = {.VID = id},
-       };
-       strncpy(ifr.device1, dev->ifname, sizeof(ifr.device1));
-       return ioctl(sock_ioctl, SIOCSIFVLAN, &ifr);
+       struct stat st;
+
+       snprintf(buf, buflen, "/sys/devices/virtual/net/%s/bridge", name);
+       if (stat(buf, &st) < 0)
+               return false;
+
+       return true;
 }
 
-int system_vlan_add(struct device *dev, int id)
+static char *system_get_bridge(const char *name, char *buf, int buflen)
 {
-       return system_vlan(dev, id);
+       char *path;
+       ssize_t len;
+       glob_t gl;
+
+       snprintf(buf, buflen, "/sys/devices/virtual/net/*/brif/%s/bridge", name);
+       if (glob(buf, GLOB_NOSORT, NULL, &gl) < 0)
+               return NULL;
+
+       if (gl.gl_pathc == 0)
+               return NULL;
+
+       len = readlink(gl.gl_pathv[0], buf, buflen);
+       if (len < 0)
+               return NULL;
+
+       buf[len] = 0;
+       path = strrchr(buf, '/');
+       if (!path)
+               return NULL;
+
+       return path + 1;
 }
 
-int system_vlan_del(struct device *dev)
+static int system_if_resolve(struct device *dev)
 {
-       return system_vlan(dev, 0);
+       struct ifreq ifr;
+       strncpy(ifr.ifr_name, dev->ifname, sizeof(ifr.ifr_name));
+       if (!ioctl(sock_ioctl, SIOCGIFINDEX, &ifr))
+               return ifr.ifr_ifindex;
+       else
+               return 0;
 }
 
-static int system_if_flags(struct device *dev, unsigned add, unsigned rem)
+static int system_if_flags(const char *ifname, unsigned add, unsigned rem)
 {
        struct ifreq ifr;
-       strncpy(ifr.ifr_name, dev->ifname, sizeof(ifr.ifr_name));
+       strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
        ioctl(sock_ioctl, SIOCGIFFLAGS, &ifr);
        ifr.ifr_flags |= add;
        ifr.ifr_flags &= ~rem;
        return ioctl(sock_ioctl, SIOCSIFFLAGS, &ifr);
 }
 
-static int system_if_resolve(struct device *dev)
+/*
+ * Clear bridge (membership) state and bring down device
+ */
+static void system_if_clear_state(struct device *dev)
 {
-       struct ifreq ifr;
-       strncpy(ifr.ifr_name, dev->ifname, sizeof(ifr.ifr_name));
-       if (!ioctl(sock_ioctl, SIOCGIFINDEX, &ifr))
-               return ifr.ifr_ifindex;
-       else
-               return 0;
+       char buf[256];
+       char *bridge;
+
+       dev->ifindex = system_if_resolve(dev);
+       if (!dev->ifindex)
+               return;
+
+       system_if_flags(dev->ifname, 0, IFF_UP);
+
+       if (system_is_bridge(dev->ifname, buf, sizeof(buf))) {
+               D(SYSTEM, "Delete existing bridge named '%s'\n", dev->ifname);
+               system_bridge_delbr(dev);
+               return;
+       }
+
+       bridge = system_get_bridge(dev->ifname, buf, sizeof(buf));
+       if (bridge) {
+               D(SYSTEM, "Remove device '%s' from bridge '%s'\n", dev->ifname, bridge);
+               system_bridge_if(bridge, dev, SIOCBRDELIF);
+       }
+}
+
+int system_bridge_addbr(struct device *bridge)
+{
+       system_if_clear_state(bridge);
+       return ioctl(sock_ioctl, SIOCBRADDBR, bridge->ifname);
+}
+
+static int system_vlan(struct device *dev, int id)
+{
+       struct vlan_ioctl_args ifr = {
+               .cmd = (id == 0) ? DEL_VLAN_CMD : ADD_VLAN_CMD,
+               .u = {.VID = id},
+       };
+       strncpy(ifr.device1, dev->ifname, sizeof(ifr.device1));
+       return ioctl(sock_ioctl, SIOCSIFVLAN, &ifr);
+}
+
+int system_vlan_add(struct device *dev, int id)
+{
+       system_if_clear_state(dev);
+       return system_vlan(dev, id);
+}
+
+int system_vlan_del(struct device *dev)
+{
+       return system_vlan(dev, 0);
 }
 
 int system_if_up(struct device *dev)
 {
        dev->ifindex = system_if_resolve(dev);
-       return system_if_flags(dev, IFF_UP, 0);
+       return system_if_flags(dev->ifname, IFF_UP, 0);
 }
 
 int system_if_down(struct device *dev)
 {
-       return system_if_flags(dev, 0, IFF_UP);
+       return system_if_flags(dev->ifname, 0, IFF_UP);
 }
 
 int system_if_check(struct device *dev)
 {
+       system_if_clear_state(dev);
        device_set_present(dev, (system_if_resolve(dev) >= 0));
        return 0;
 }