diff options
| -rw-r--r-- | Documentation/lguest/lguest.c | 122 |
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...]"); } |
