1 files changed, 89 insertions, 33 deletions

diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c
index 686e2d435c75..684d61191bee 100644
--- a/Documentation/lguest/lguest.c
+++ b/Documentation/lguest/lguest.c
@@ -1265,10 +1265,25 @@ static void setup_console(void)
 
 static u32 str2ip(const char *ipaddr)
 {
-        unsigned int byte[4];
+        unsigned int b[4];
 
-        sscanf(ipaddr, "%u.%u.%u.%u", &byte[0], &byte[1], &byte[2], &byte[3]);
-        return (byte[0] << 24) | (byte[1] << 16) | (byte[2] << 8) | byte[3];
+        if (sscanf(ipaddr, "%u.%u.%u.%u", &b[0], &b[1], &b[2], &b[3]) != 4)
+                errx(1, "Failed to parse IP address '%s'", ipaddr);
+        return (b[0] << 24) | (b[1] << 16) | (b[2] << 8) | b[3];
+}
+
+static void str2mac(const char *macaddr, unsigned char mac[6])
+{
+        unsigned int m[6];
+        if (sscanf(macaddr, "%02x:%02x:%02x:%02x:%02x:%02x",
+                   &m[0], &m[1], &m[2], &m[3], &m[4], &m[5]) != 6)
+                errx(1, "Failed to parse mac address '%s'", macaddr);
+        mac[0] = m[0];
+        mac[1] = m[1];
+        mac[2] = m[2];
+        mac[3] = m[3];
+        mac[4] = m[4];
+        mac[5] = m[5];
 }
 
 /* This code is "adapted" from libbridge: it attaches the Host end of the
@@ -1289,6 +1304,7 @@ static void add_to_bridge(int fd, const char *if_name, const char *br_name)
                 errx(1, "interface %s does not exist!", if_name);
 
         strncpy(ifr.ifr_name, br_name, IFNAMSIZ);
+        ifr.ifr_name[IFNAMSIZ-1] = '\0';
         ifr.ifr_ifindex = ifidx;
         if (ioctl(fd, SIOCBRADDIF, &ifr) < 0)
                 err(1, "can't add %s to bridge %s", if_name, br_name);
@@ -1297,58 +1313,80 @@ static void add_to_bridge(int fd, const char *if_name, const char *br_name)
 /* This sets up the Host end of the network device with an IP address, brings
  * it up so packets will flow, the copies the MAC address into the hwaddr
  * pointer. */
-static void configure_device(int fd, const char *devname, u32 ipaddr,
-                             unsigned char hwaddr[6])
+static void configure_device(int fd, const char *tapif, u32 ipaddr)
 {
         struct ifreq ifr;
         struct sockaddr_in *sin = (struct sockaddr_in *)&ifr.ifr_addr;
 
-        /* Don't read these incantations.  Just cut & paste them like I did! */
         memset(&ifr, 0, sizeof(ifr));
-        strcpy(ifr.ifr_name, devname);
+        strcpy(ifr.ifr_name, tapif);
+
+        /* Don't read these incantations.  Just cut & paste them like I did! */
         sin->sin_family = AF_INET;
         sin->sin_addr.s_addr = htonl(ipaddr);
         if (ioctl(fd, SIOCSIFADDR, &ifr) != 0)
-                err(1, "Setting %s interface address", devname);
+                err(1, "Setting %s interface address", tapif);
         ifr.ifr_flags = IFF_UP;
         if (ioctl(fd, SIOCSIFFLAGS, &ifr) != 0)
-                err(1, "Bringing interface %s up", devname);
+                err(1, "Bringing interface %s up", tapif);
+}
+
+static void get_mac(int fd, const char *tapif, unsigned char hwaddr[6])
+{
+        struct ifreq ifr;
+
+        memset(&ifr, 0, sizeof(ifr));
+        strcpy(ifr.ifr_name, tapif);
 
         /* SIOC stands for Socket I/O Control.  G means Get (vs S for Set
          * above).  IF means Interface, and HWADDR is hardware address.
          * Simple! */
         if (ioctl(fd, SIOCGIFHWADDR, &ifr) != 0)
-                err(1, "getting hw address for %s", devname);
+                err(1, "getting hw address for %s", tapif);
         memcpy(hwaddr, ifr.ifr_hwaddr.sa_data, 6);
 }
 
-/*L:195 Our network is a Host<->Guest network.  This can either use bridging or
- * routing, but the principle is the same: it uses the "tun" device to inject
- * packets into the Host as if they came in from a normal network card.  We
- * just shunt packets between the Guest and the tun device. */
-static void setup_tun_net(const char *arg)
+static int get_tun_device(char tapif[IFNAMSIZ])
 {
-        struct device *dev;
         struct ifreq ifr;
-        int netfd, ipfd;
-        u32 ip;
-        const char *br_name = NULL;
-        struct virtio_net_config conf;
+        int netfd;
+
+        /* Start with this zeroed.  Messy but sure. */
+        memset(&ifr, 0, sizeof(ifr));
 
         /* We open the /dev/net/tun device and tell it we want a tap device.  A
          * tap device is like a tun device, only somehow different.  To tell
          * the truth, I completely blundered my way through this code, but it
          * works now! */
         netfd = open_or_die("/dev/net/tun", O_RDWR);
-        memset(&ifr, 0, sizeof(ifr));
         ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
         strcpy(ifr.ifr_name, "tap%d");
         if (ioctl(netfd, TUNSETIFF, &ifr) != 0)
                 err(1, "configuring /dev/net/tun");
+
         /* We don't need checksums calculated for packets coming in this
          * device: trust us! */
         ioctl(netfd, TUNSETNOCSUM, 1);
 
+        memcpy(tapif, ifr.ifr_name, IFNAMSIZ);
+        return netfd;
+}
+
+/*L:195 Our network is a Host<->Guest network.  This can either use bridging or
+ * routing, but the principle is the same: it uses the "tun" device to inject
+ * packets into the Host as if they came in from a normal network card.  We
+ * just shunt packets between the Guest and the tun device. */
+static void setup_tun_net(char *arg)
+{
+        struct device *dev;
+        int netfd, ipfd;
+        u32 ip = INADDR_ANY;
+        bool bridging = false;
+        char tapif[IFNAMSIZ], *p;
+        struct virtio_net_config conf;
+
+        netfd = get_tun_device(tapif);
+
         /* First we create a new network device. */
         dev = new_device("net", VIRTIO_ID_NET, netfd, handle_tun_input);
 
@@ -1365,14 +1403,29 @@ static void setup_tun_net(const char *arg)
 
         /* If the command line was --tunnet=bridge:<name> do bridging. */
         if (!strncmp(BRIDGE_PFX, arg, strlen(BRIDGE_PFX))) {
-                ip = INADDR_ANY;
-                br_name = arg + strlen(BRIDGE_PFX);
-                add_to_bridge(ipfd, ifr.ifr_name, br_name);
-        } else /* It is an IP address to set up the device with */
+                arg += strlen(BRIDGE_PFX);
+                bridging = true;
+        }
+
+        /* A mac address may follow the bridge name or IP address */
+        p = strchr(arg, ':');
+        if (p) {
+                str2mac(p+1, conf.mac);
+                *p = '\0';
+        } else {
+                p = arg + strlen(arg);
+                /* None supplied; query the randomly assigned mac. */
+                get_mac(ipfd, tapif, conf.mac);
+        }
+
+        /* arg is now either an IP address or a bridge name */
+        if (bridging)
+                add_to_bridge(ipfd, tapif, arg);
+        else
                 ip = str2ip(arg);
 
-        /* Set up the tun device, and get the mac address for the interface. */
-        configure_device(ipfd, ifr.ifr_name, ip, conf.mac);
+        /* Set up the tun device. */
+        configure_device(ipfd, tapif, ip);
 
         /* Tell Guest what MAC address to use. */
         add_feature(dev, VIRTIO_NET_F_MAC);
@@ -1382,11 +1435,14 @@ static void setup_tun_net(const char *arg)
         /* We don't need the socket any more; setup is done. */
         close(ipfd);
 
-        verbose("device %u: tun net %u.%u.%u.%u\n",
-                devices.device_num++,
-                (u8)(ip>>24),(u8)(ip>>16),(u8)(ip>>8),(u8)ip);
-        if (br_name)
-                verbose("attached to bridge: %s\n", br_name);
+        devices.device_num++;
+
+        if (bridging)
+                verbose("device %u: tun %s attached to bridge: %s\n",
+                        devices.device_num, tapif, arg);
+        else
+                verbose("device %u: tun %s: %s\n",
+                        devices.device_num, tapif, arg);
 }
 
 /* Our block (disk) device should be really simple: the Guest asks for a block
@@ -1698,7 +1754,7 @@ static struct option opts[] = {
 static void usage(void)
 {
         errx(1, "Usage: lguest [--verbose] "
-             "[--tunnet=(<ipaddr>|bridge:<bridgename>)\n"
+             "[--tunnet=(<ipaddr>:<macaddr>|bridge:<bridgename>:<macaddr>)\n"
              "|--block=<filename>|--initrd=<filename>]...\n"
              "<mem-in-mb> vmlinux [args...]");
 }