17b93fadfSCorey Bryant /* 27b93fadfSCorey Bryant * QEMU Bridge Helper 37b93fadfSCorey Bryant * 47b93fadfSCorey Bryant * Copyright IBM, Corp. 2011 57b93fadfSCorey Bryant * 67b93fadfSCorey Bryant * Authors: 77b93fadfSCorey Bryant * Anthony Liguori <aliguori@us.ibm.com> 87b93fadfSCorey Bryant * Richa Marwaha <rmarwah@linux.vnet.ibm.com> 97b93fadfSCorey Bryant * Corey Bryant <coreyb@linux.vnet.ibm.com> 107b93fadfSCorey Bryant * 117b93fadfSCorey Bryant * This work is licensed under the terms of the GNU GPL, version 2. See 127b93fadfSCorey Bryant * the COPYING file in the top-level directory. 137b93fadfSCorey Bryant * 147b93fadfSCorey Bryant */ 157b93fadfSCorey Bryant 167b93fadfSCorey Bryant #include "config-host.h" 177b93fadfSCorey Bryant 187b93fadfSCorey Bryant #include <stdio.h> 197b93fadfSCorey Bryant #include <errno.h> 207b93fadfSCorey Bryant #include <fcntl.h> 217b93fadfSCorey Bryant #include <unistd.h> 227b93fadfSCorey Bryant #include <string.h> 237b93fadfSCorey Bryant #include <stdlib.h> 247b93fadfSCorey Bryant #include <stdbool.h> 257b93fadfSCorey Bryant #include <ctype.h> 26*bdef79a2SCorey Bryant #include <glib.h> 277b93fadfSCorey Bryant 287b93fadfSCorey Bryant #include <sys/types.h> 297b93fadfSCorey Bryant #include <sys/ioctl.h> 307b93fadfSCorey Bryant #include <sys/socket.h> 317b93fadfSCorey Bryant #include <sys/un.h> 327b93fadfSCorey Bryant #include <sys/prctl.h> 337b93fadfSCorey Bryant 347b93fadfSCorey Bryant #include <net/if.h> 357b93fadfSCorey Bryant 367b93fadfSCorey Bryant #include <linux/sockios.h> 377b93fadfSCorey Bryant 38*bdef79a2SCorey Bryant #include "qemu-queue.h" 39*bdef79a2SCorey Bryant 407b93fadfSCorey Bryant #include "net/tap-linux.h" 417b93fadfSCorey Bryant 42*bdef79a2SCorey Bryant #define DEFAULT_ACL_FILE CONFIG_QEMU_CONFDIR "/bridge.conf" 43*bdef79a2SCorey Bryant 44*bdef79a2SCorey Bryant enum { 45*bdef79a2SCorey Bryant ACL_ALLOW = 0, 46*bdef79a2SCorey Bryant ACL_ALLOW_ALL, 47*bdef79a2SCorey Bryant ACL_DENY, 48*bdef79a2SCorey Bryant ACL_DENY_ALL, 49*bdef79a2SCorey Bryant }; 50*bdef79a2SCorey Bryant 51*bdef79a2SCorey Bryant typedef struct ACLRule { 52*bdef79a2SCorey Bryant int type; 53*bdef79a2SCorey Bryant char iface[IFNAMSIZ]; 54*bdef79a2SCorey Bryant QSIMPLEQ_ENTRY(ACLRule) entry; 55*bdef79a2SCorey Bryant } ACLRule; 56*bdef79a2SCorey Bryant 57*bdef79a2SCorey Bryant typedef QSIMPLEQ_HEAD(ACLList, ACLRule) ACLList; 58*bdef79a2SCorey Bryant 597b93fadfSCorey Bryant static void usage(void) 607b93fadfSCorey Bryant { 617b93fadfSCorey Bryant fprintf(stderr, 627b93fadfSCorey Bryant "Usage: qemu-bridge-helper [--use-vnet] --br=bridge --fd=unixfd\n"); 637b93fadfSCorey Bryant } 647b93fadfSCorey Bryant 65*bdef79a2SCorey Bryant static int parse_acl_file(const char *filename, ACLList *acl_list) 66*bdef79a2SCorey Bryant { 67*bdef79a2SCorey Bryant FILE *f; 68*bdef79a2SCorey Bryant char line[4096]; 69*bdef79a2SCorey Bryant ACLRule *acl_rule; 70*bdef79a2SCorey Bryant 71*bdef79a2SCorey Bryant f = fopen(filename, "r"); 72*bdef79a2SCorey Bryant if (f == NULL) { 73*bdef79a2SCorey Bryant return -1; 74*bdef79a2SCorey Bryant } 75*bdef79a2SCorey Bryant 76*bdef79a2SCorey Bryant while (fgets(line, sizeof(line), f) != NULL) { 77*bdef79a2SCorey Bryant char *ptr = line; 78*bdef79a2SCorey Bryant char *cmd, *arg, *argend; 79*bdef79a2SCorey Bryant 80*bdef79a2SCorey Bryant while (isspace(*ptr)) { 81*bdef79a2SCorey Bryant ptr++; 82*bdef79a2SCorey Bryant } 83*bdef79a2SCorey Bryant 84*bdef79a2SCorey Bryant /* skip comments and empty lines */ 85*bdef79a2SCorey Bryant if (*ptr == '#' || *ptr == 0) { 86*bdef79a2SCorey Bryant continue; 87*bdef79a2SCorey Bryant } 88*bdef79a2SCorey Bryant 89*bdef79a2SCorey Bryant cmd = ptr; 90*bdef79a2SCorey Bryant arg = strchr(cmd, ' '); 91*bdef79a2SCorey Bryant if (arg == NULL) { 92*bdef79a2SCorey Bryant arg = strchr(cmd, '\t'); 93*bdef79a2SCorey Bryant } 94*bdef79a2SCorey Bryant 95*bdef79a2SCorey Bryant if (arg == NULL) { 96*bdef79a2SCorey Bryant fprintf(stderr, "Invalid config line:\n %s\n", line); 97*bdef79a2SCorey Bryant fclose(f); 98*bdef79a2SCorey Bryant errno = EINVAL; 99*bdef79a2SCorey Bryant return -1; 100*bdef79a2SCorey Bryant } 101*bdef79a2SCorey Bryant 102*bdef79a2SCorey Bryant *arg = 0; 103*bdef79a2SCorey Bryant arg++; 104*bdef79a2SCorey Bryant while (isspace(*arg)) { 105*bdef79a2SCorey Bryant arg++; 106*bdef79a2SCorey Bryant } 107*bdef79a2SCorey Bryant 108*bdef79a2SCorey Bryant argend = arg + strlen(arg); 109*bdef79a2SCorey Bryant while (arg != argend && isspace(*(argend - 1))) { 110*bdef79a2SCorey Bryant argend--; 111*bdef79a2SCorey Bryant } 112*bdef79a2SCorey Bryant *argend = 0; 113*bdef79a2SCorey Bryant 114*bdef79a2SCorey Bryant if (strcmp(cmd, "deny") == 0) { 115*bdef79a2SCorey Bryant acl_rule = g_malloc(sizeof(*acl_rule)); 116*bdef79a2SCorey Bryant if (strcmp(arg, "all") == 0) { 117*bdef79a2SCorey Bryant acl_rule->type = ACL_DENY_ALL; 118*bdef79a2SCorey Bryant } else { 119*bdef79a2SCorey Bryant acl_rule->type = ACL_DENY; 120*bdef79a2SCorey Bryant snprintf(acl_rule->iface, IFNAMSIZ, "%s", arg); 121*bdef79a2SCorey Bryant } 122*bdef79a2SCorey Bryant QSIMPLEQ_INSERT_TAIL(acl_list, acl_rule, entry); 123*bdef79a2SCorey Bryant } else if (strcmp(cmd, "allow") == 0) { 124*bdef79a2SCorey Bryant acl_rule = g_malloc(sizeof(*acl_rule)); 125*bdef79a2SCorey Bryant if (strcmp(arg, "all") == 0) { 126*bdef79a2SCorey Bryant acl_rule->type = ACL_ALLOW_ALL; 127*bdef79a2SCorey Bryant } else { 128*bdef79a2SCorey Bryant acl_rule->type = ACL_ALLOW; 129*bdef79a2SCorey Bryant snprintf(acl_rule->iface, IFNAMSIZ, "%s", arg); 130*bdef79a2SCorey Bryant } 131*bdef79a2SCorey Bryant QSIMPLEQ_INSERT_TAIL(acl_list, acl_rule, entry); 132*bdef79a2SCorey Bryant } else if (strcmp(cmd, "include") == 0) { 133*bdef79a2SCorey Bryant /* ignore errors */ 134*bdef79a2SCorey Bryant parse_acl_file(arg, acl_list); 135*bdef79a2SCorey Bryant } else { 136*bdef79a2SCorey Bryant fprintf(stderr, "Unknown command `%s'\n", cmd); 137*bdef79a2SCorey Bryant fclose(f); 138*bdef79a2SCorey Bryant errno = EINVAL; 139*bdef79a2SCorey Bryant return -1; 140*bdef79a2SCorey Bryant } 141*bdef79a2SCorey Bryant } 142*bdef79a2SCorey Bryant 143*bdef79a2SCorey Bryant fclose(f); 144*bdef79a2SCorey Bryant 145*bdef79a2SCorey Bryant return 0; 146*bdef79a2SCorey Bryant } 147*bdef79a2SCorey Bryant 1487b93fadfSCorey Bryant static bool has_vnet_hdr(int fd) 1497b93fadfSCorey Bryant { 1507b93fadfSCorey Bryant unsigned int features = 0; 1517b93fadfSCorey Bryant 1527b93fadfSCorey Bryant if (ioctl(fd, TUNGETFEATURES, &features) == -1) { 1537b93fadfSCorey Bryant return false; 1547b93fadfSCorey Bryant } 1557b93fadfSCorey Bryant 1567b93fadfSCorey Bryant if (!(features & IFF_VNET_HDR)) { 1577b93fadfSCorey Bryant return false; 1587b93fadfSCorey Bryant } 1597b93fadfSCorey Bryant 1607b93fadfSCorey Bryant return true; 1617b93fadfSCorey Bryant } 1627b93fadfSCorey Bryant 1637b93fadfSCorey Bryant static void prep_ifreq(struct ifreq *ifr, const char *ifname) 1647b93fadfSCorey Bryant { 1657b93fadfSCorey Bryant memset(ifr, 0, sizeof(*ifr)); 1667b93fadfSCorey Bryant snprintf(ifr->ifr_name, IFNAMSIZ, "%s", ifname); 1677b93fadfSCorey Bryant } 1687b93fadfSCorey Bryant 1697b93fadfSCorey Bryant static int send_fd(int c, int fd) 1707b93fadfSCorey Bryant { 1717b93fadfSCorey Bryant char msgbuf[CMSG_SPACE(sizeof(fd))]; 1727b93fadfSCorey Bryant struct msghdr msg = { 1737b93fadfSCorey Bryant .msg_control = msgbuf, 1747b93fadfSCorey Bryant .msg_controllen = sizeof(msgbuf), 1757b93fadfSCorey Bryant }; 1767b93fadfSCorey Bryant struct cmsghdr *cmsg; 1777b93fadfSCorey Bryant struct iovec iov; 1787b93fadfSCorey Bryant char req[1] = { 0x00 }; 1797b93fadfSCorey Bryant 1807b93fadfSCorey Bryant cmsg = CMSG_FIRSTHDR(&msg); 1817b93fadfSCorey Bryant cmsg->cmsg_level = SOL_SOCKET; 1827b93fadfSCorey Bryant cmsg->cmsg_type = SCM_RIGHTS; 1837b93fadfSCorey Bryant cmsg->cmsg_len = CMSG_LEN(sizeof(fd)); 1847b93fadfSCorey Bryant msg.msg_controllen = cmsg->cmsg_len; 1857b93fadfSCorey Bryant 1867b93fadfSCorey Bryant iov.iov_base = req; 1877b93fadfSCorey Bryant iov.iov_len = sizeof(req); 1887b93fadfSCorey Bryant 1897b93fadfSCorey Bryant msg.msg_iov = &iov; 1907b93fadfSCorey Bryant msg.msg_iovlen = 1; 1917b93fadfSCorey Bryant memcpy(CMSG_DATA(cmsg), &fd, sizeof(fd)); 1927b93fadfSCorey Bryant 1937b93fadfSCorey Bryant return sendmsg(c, &msg, 0); 1947b93fadfSCorey Bryant } 1957b93fadfSCorey Bryant 1967b93fadfSCorey Bryant int main(int argc, char **argv) 1977b93fadfSCorey Bryant { 1987b93fadfSCorey Bryant struct ifreq ifr; 1997b93fadfSCorey Bryant int fd, ctlfd, unixfd = -1; 2007b93fadfSCorey Bryant int use_vnet = 0; 2017b93fadfSCorey Bryant int mtu; 2027b93fadfSCorey Bryant const char *bridge = NULL; 2037b93fadfSCorey Bryant char iface[IFNAMSIZ]; 2047b93fadfSCorey Bryant int index; 205*bdef79a2SCorey Bryant ACLRule *acl_rule; 206*bdef79a2SCorey Bryant ACLList acl_list; 207*bdef79a2SCorey Bryant int access_allowed, access_denied; 2087b93fadfSCorey Bryant int ret = EXIT_SUCCESS; 2097b93fadfSCorey Bryant 2107b93fadfSCorey Bryant /* parse arguments */ 2117b93fadfSCorey Bryant for (index = 1; index < argc; index++) { 2127b93fadfSCorey Bryant if (strcmp(argv[index], "--use-vnet") == 0) { 2137b93fadfSCorey Bryant use_vnet = 1; 2147b93fadfSCorey Bryant } else if (strncmp(argv[index], "--br=", 5) == 0) { 2157b93fadfSCorey Bryant bridge = &argv[index][5]; 2167b93fadfSCorey Bryant } else if (strncmp(argv[index], "--fd=", 5) == 0) { 2177b93fadfSCorey Bryant unixfd = atoi(&argv[index][5]); 2187b93fadfSCorey Bryant } else { 2197b93fadfSCorey Bryant usage(); 2207b93fadfSCorey Bryant return EXIT_FAILURE; 2217b93fadfSCorey Bryant } 2227b93fadfSCorey Bryant } 2237b93fadfSCorey Bryant 2247b93fadfSCorey Bryant if (bridge == NULL || unixfd == -1) { 2257b93fadfSCorey Bryant usage(); 2267b93fadfSCorey Bryant return EXIT_FAILURE; 2277b93fadfSCorey Bryant } 2287b93fadfSCorey Bryant 229*bdef79a2SCorey Bryant /* parse default acl file */ 230*bdef79a2SCorey Bryant QSIMPLEQ_INIT(&acl_list); 231*bdef79a2SCorey Bryant if (parse_acl_file(DEFAULT_ACL_FILE, &acl_list) == -1) { 232*bdef79a2SCorey Bryant fprintf(stderr, "failed to parse default acl file `%s'\n", 233*bdef79a2SCorey Bryant DEFAULT_ACL_FILE); 234*bdef79a2SCorey Bryant ret = EXIT_FAILURE; 235*bdef79a2SCorey Bryant goto cleanup; 236*bdef79a2SCorey Bryant } 237*bdef79a2SCorey Bryant 238*bdef79a2SCorey Bryant /* validate bridge against acl -- default policy is to deny 239*bdef79a2SCorey Bryant * according acl policy if we have a deny and allow both 240*bdef79a2SCorey Bryant * then deny should always win over allow 241*bdef79a2SCorey Bryant */ 242*bdef79a2SCorey Bryant access_allowed = 0; 243*bdef79a2SCorey Bryant access_denied = 0; 244*bdef79a2SCorey Bryant QSIMPLEQ_FOREACH(acl_rule, &acl_list, entry) { 245*bdef79a2SCorey Bryant switch (acl_rule->type) { 246*bdef79a2SCorey Bryant case ACL_ALLOW_ALL: 247*bdef79a2SCorey Bryant access_allowed = 1; 248*bdef79a2SCorey Bryant break; 249*bdef79a2SCorey Bryant case ACL_ALLOW: 250*bdef79a2SCorey Bryant if (strcmp(bridge, acl_rule->iface) == 0) { 251*bdef79a2SCorey Bryant access_allowed = 1; 252*bdef79a2SCorey Bryant } 253*bdef79a2SCorey Bryant break; 254*bdef79a2SCorey Bryant case ACL_DENY_ALL: 255*bdef79a2SCorey Bryant access_denied = 1; 256*bdef79a2SCorey Bryant break; 257*bdef79a2SCorey Bryant case ACL_DENY: 258*bdef79a2SCorey Bryant if (strcmp(bridge, acl_rule->iface) == 0) { 259*bdef79a2SCorey Bryant access_denied = 1; 260*bdef79a2SCorey Bryant } 261*bdef79a2SCorey Bryant break; 262*bdef79a2SCorey Bryant } 263*bdef79a2SCorey Bryant } 264*bdef79a2SCorey Bryant 265*bdef79a2SCorey Bryant if ((access_allowed == 0) || (access_denied == 1)) { 266*bdef79a2SCorey Bryant fprintf(stderr, "access denied by acl file\n"); 267*bdef79a2SCorey Bryant ret = EXIT_FAILURE; 268*bdef79a2SCorey Bryant goto cleanup; 269*bdef79a2SCorey Bryant } 270*bdef79a2SCorey Bryant 2717b93fadfSCorey Bryant /* open a socket to use to control the network interfaces */ 2727b93fadfSCorey Bryant ctlfd = socket(AF_INET, SOCK_STREAM, 0); 2737b93fadfSCorey Bryant if (ctlfd == -1) { 2747b93fadfSCorey Bryant fprintf(stderr, "failed to open control socket: %s\n", strerror(errno)); 2757b93fadfSCorey Bryant ret = EXIT_FAILURE; 2767b93fadfSCorey Bryant goto cleanup; 2777b93fadfSCorey Bryant } 2787b93fadfSCorey Bryant 2797b93fadfSCorey Bryant /* open the tap device */ 2807b93fadfSCorey Bryant fd = open("/dev/net/tun", O_RDWR); 2817b93fadfSCorey Bryant if (fd == -1) { 2827b93fadfSCorey Bryant fprintf(stderr, "failed to open /dev/net/tun: %s\n", strerror(errno)); 2837b93fadfSCorey Bryant ret = EXIT_FAILURE; 2847b93fadfSCorey Bryant goto cleanup; 2857b93fadfSCorey Bryant } 2867b93fadfSCorey Bryant 2877b93fadfSCorey Bryant /* request a tap device, disable PI, and add vnet header support if 2887b93fadfSCorey Bryant * requested and it's available. */ 2897b93fadfSCorey Bryant prep_ifreq(&ifr, "tap%d"); 2907b93fadfSCorey Bryant ifr.ifr_flags = IFF_TAP|IFF_NO_PI; 2917b93fadfSCorey Bryant if (use_vnet && has_vnet_hdr(fd)) { 2927b93fadfSCorey Bryant ifr.ifr_flags |= IFF_VNET_HDR; 2937b93fadfSCorey Bryant } 2947b93fadfSCorey Bryant 2957b93fadfSCorey Bryant if (ioctl(fd, TUNSETIFF, &ifr) == -1) { 2967b93fadfSCorey Bryant fprintf(stderr, "failed to create tun device: %s\n", strerror(errno)); 2977b93fadfSCorey Bryant ret = EXIT_FAILURE; 2987b93fadfSCorey Bryant goto cleanup; 2997b93fadfSCorey Bryant } 3007b93fadfSCorey Bryant 3017b93fadfSCorey Bryant /* save tap device name */ 3027b93fadfSCorey Bryant snprintf(iface, sizeof(iface), "%s", ifr.ifr_name); 3037b93fadfSCorey Bryant 3047b93fadfSCorey Bryant /* get the mtu of the bridge */ 3057b93fadfSCorey Bryant prep_ifreq(&ifr, bridge); 3067b93fadfSCorey Bryant if (ioctl(ctlfd, SIOCGIFMTU, &ifr) == -1) { 3077b93fadfSCorey Bryant fprintf(stderr, "failed to get mtu of bridge `%s': %s\n", 3087b93fadfSCorey Bryant bridge, strerror(errno)); 3097b93fadfSCorey Bryant ret = EXIT_FAILURE; 3107b93fadfSCorey Bryant goto cleanup; 3117b93fadfSCorey Bryant } 3127b93fadfSCorey Bryant 3137b93fadfSCorey Bryant /* save mtu */ 3147b93fadfSCorey Bryant mtu = ifr.ifr_mtu; 3157b93fadfSCorey Bryant 3167b93fadfSCorey Bryant /* set the mtu of the interface based on the bridge */ 3177b93fadfSCorey Bryant prep_ifreq(&ifr, iface); 3187b93fadfSCorey Bryant ifr.ifr_mtu = mtu; 3197b93fadfSCorey Bryant if (ioctl(ctlfd, SIOCSIFMTU, &ifr) == -1) { 3207b93fadfSCorey Bryant fprintf(stderr, "failed to set mtu of device `%s' to %d: %s\n", 3217b93fadfSCorey Bryant iface, mtu, strerror(errno)); 3227b93fadfSCorey Bryant ret = EXIT_FAILURE; 3237b93fadfSCorey Bryant goto cleanup; 3247b93fadfSCorey Bryant } 3257b93fadfSCorey Bryant 3267b93fadfSCorey Bryant /* add the interface to the bridge */ 3277b93fadfSCorey Bryant prep_ifreq(&ifr, bridge); 3287b93fadfSCorey Bryant ifr.ifr_ifindex = if_nametoindex(iface); 3297b93fadfSCorey Bryant 3307b93fadfSCorey Bryant if (ioctl(ctlfd, SIOCBRADDIF, &ifr) == -1) { 3317b93fadfSCorey Bryant fprintf(stderr, "failed to add interface `%s' to bridge `%s': %s\n", 3327b93fadfSCorey Bryant iface, bridge, strerror(errno)); 3337b93fadfSCorey Bryant ret = EXIT_FAILURE; 3347b93fadfSCorey Bryant goto cleanup; 3357b93fadfSCorey Bryant } 3367b93fadfSCorey Bryant 3377b93fadfSCorey Bryant /* bring the interface up */ 3387b93fadfSCorey Bryant prep_ifreq(&ifr, iface); 3397b93fadfSCorey Bryant if (ioctl(ctlfd, SIOCGIFFLAGS, &ifr) == -1) { 3407b93fadfSCorey Bryant fprintf(stderr, "failed to get interface flags for `%s': %s\n", 3417b93fadfSCorey Bryant iface, strerror(errno)); 3427b93fadfSCorey Bryant ret = EXIT_FAILURE; 3437b93fadfSCorey Bryant goto cleanup; 3447b93fadfSCorey Bryant } 3457b93fadfSCorey Bryant 3467b93fadfSCorey Bryant ifr.ifr_flags |= IFF_UP; 3477b93fadfSCorey Bryant if (ioctl(ctlfd, SIOCSIFFLAGS, &ifr) == -1) { 3487b93fadfSCorey Bryant fprintf(stderr, "failed to bring up interface `%s': %s\n", 3497b93fadfSCorey Bryant iface, strerror(errno)); 3507b93fadfSCorey Bryant ret = EXIT_FAILURE; 3517b93fadfSCorey Bryant goto cleanup; 3527b93fadfSCorey Bryant } 3537b93fadfSCorey Bryant 3547b93fadfSCorey Bryant /* write fd to the domain socket */ 3557b93fadfSCorey Bryant if (send_fd(unixfd, fd) == -1) { 3567b93fadfSCorey Bryant fprintf(stderr, "failed to write fd to unix socket: %s\n", 3577b93fadfSCorey Bryant strerror(errno)); 3587b93fadfSCorey Bryant ret = EXIT_FAILURE; 3597b93fadfSCorey Bryant goto cleanup; 3607b93fadfSCorey Bryant } 3617b93fadfSCorey Bryant 3627b93fadfSCorey Bryant /* ... */ 3637b93fadfSCorey Bryant 3647b93fadfSCorey Bryant /* profit! */ 3657b93fadfSCorey Bryant 3667b93fadfSCorey Bryant cleanup: 3677b93fadfSCorey Bryant 368*bdef79a2SCorey Bryant while ((acl_rule = QSIMPLEQ_FIRST(&acl_list)) != NULL) { 369*bdef79a2SCorey Bryant QSIMPLEQ_REMOVE_HEAD(&acl_list, entry); 370*bdef79a2SCorey Bryant g_free(acl_rule); 371*bdef79a2SCorey Bryant } 372*bdef79a2SCorey Bryant 3737b93fadfSCorey Bryant return ret; 3747b93fadfSCorey Bryant } 375