/* * iptunnel.c "ip tuntap" * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. * * Authors: David Woodhouse * */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "rt_names.h" #include "utils.h" #include "ip_common.h" #define TUNDEV "/dev/net/tun" static void usage(void) __attribute__((noreturn)); static void usage(void) { fprintf(stderr, "Usage: ip tuntap { add | del } [ dev PHYS_DEV ] \n"); fprintf(stderr, " [ mode { tun | tap } ] [ user USER ] [ group GROUP ]\n"); fprintf(stderr, " [ one_queue ] [ pi ] [ vnet_hdr ] [ multi_queue ]\n"); fprintf(stderr, "\n"); fprintf(stderr, "Where: USER := { STRING | NUMBER }\n"); fprintf(stderr, " GROUP := { STRING | NUMBER }\n"); exit(-1); } static int tap_add_ioctl(struct ifreq *ifr, uid_t uid, gid_t gid) { int fd; int ret = -1; #ifdef IFF_TUN_EXCL ifr->ifr_flags |= IFF_TUN_EXCL; #endif fd = open(TUNDEV, O_RDWR); if (fd < 0) { perror("open"); return -1; } if (ioctl(fd, TUNSETIFF, ifr)) { perror("ioctl(TUNSETIFF)"); goto out; } if (uid != -1 && ioctl(fd, TUNSETOWNER, uid)) { perror("ioctl(TUNSETOWNER)"); goto out; } if (gid != -1 && ioctl(fd, TUNSETGROUP, gid)) { perror("ioctl(TUNSETGROUP)"); goto out; } if (ioctl(fd, TUNSETPERSIST, 1)) { perror("ioctl(TUNSETPERSIST)"); goto out; } ret = 0; out: close(fd); return ret; } static int tap_del_ioctl(struct ifreq *ifr) { int fd = open(TUNDEV, O_RDWR); int ret = -1; if (fd < 0) { perror("open"); return -1; } if (ioctl(fd, TUNSETIFF, ifr)) { perror("ioctl(TUNSETIFF)"); goto out; } if (ioctl(fd, TUNSETPERSIST, 0)) { perror("ioctl(TUNSETPERSIST)"); goto out; } ret = 0; out: close(fd); return ret; } static int parse_args(int argc, char **argv, struct ifreq *ifr, uid_t *uid, gid_t *gid) { int count = 0; memset(ifr, 0, sizeof(*ifr)); ifr->ifr_flags |= IFF_NO_PI; while (argc > 0) { if (matches(*argv, "mode") == 0) { NEXT_ARG(); if (matches(*argv, "tun") == 0) { if (ifr->ifr_flags & IFF_TAP) { fprintf(stderr,"You managed to ask for more than one tunnel mode.\n"); exit(-1); } ifr->ifr_flags |= IFF_TUN; } else if (matches(*argv, "tap") == 0) { if (ifr->ifr_flags & IFF_TUN) { fprintf(stderr,"You managed to ask for more than one tunnel mode.\n"); exit(-1); } ifr->ifr_flags |= IFF_TAP; } else { fprintf(stderr,"Unknown tunnel mode \"%s\"\n", *argv); exit(-1); } } else if (uid && matches(*argv, "user") == 0) { char *end; unsigned long user; NEXT_ARG(); if (**argv && ((user = strtol(*argv, &end, 10)), !*end)) *uid = user; else { struct passwd *pw = getpwnam(*argv); if (!pw) { fprintf(stderr, "invalid user \"%s\"\n", *argv); exit(-1); } *uid = pw->pw_uid; } } else if (gid && matches(*argv, "group") == 0) { char *end; unsigned long group; NEXT_ARG(); if (**argv && ((group = strtol(*argv, &end, 10)), !*end)) *gid = group; else { struct group *gr = getgrnam(*argv); if (!gr) { fprintf(stderr, "invalid group \"%s\"\n", *argv); exit(-1); } *gid = gr->gr_gid; } } else if (matches(*argv, "pi") == 0) { ifr->ifr_flags &= ~IFF_NO_PI; } else if (matches(*argv, "one_queue") == 0) { ifr->ifr_flags |= IFF_ONE_QUEUE; } else if (matches(*argv, "vnet_hdr") == 0) { ifr->ifr_flags |= IFF_VNET_HDR; } else if (matches(*argv, "multi_queue") == 0) { ifr->ifr_flags |= IFF_MULTI_QUEUE; } else if (matches(*argv, "dev") == 0) { NEXT_ARG(); strncpy(ifr->ifr_name, *argv, IFNAMSIZ-1); } else { if (matches(*argv, "name") == 0) { NEXT_ARG(); } else if (matches(*argv, "help") == 0) usage(); if (ifr->ifr_name[0]) duparg2("name", *argv); strncpy(ifr->ifr_name, *argv, IFNAMSIZ); } count++; argc--; argv++; } return 0; } static int do_add(int argc, char **argv) { struct ifreq ifr; uid_t uid = -1; gid_t gid = -1; if (parse_args(argc, argv, &ifr, &uid, &gid) < 0) return -1; if (!(ifr.ifr_flags & TUN_TYPE_MASK)) { fprintf(stderr, "You failed to specify a tunnel mode\n"); return -1; } return tap_add_ioctl(&ifr, uid, gid); } static int do_del(int argc, char **argv) { struct ifreq ifr; if (parse_args(argc, argv, &ifr, NULL, NULL) < 0) return -1; return tap_del_ioctl(&ifr); } static int read_prop(char *dev, char *prop, long *value) { char fname[IFNAMSIZ+25], buf[80], *endp; ssize_t len; int fd; long result; sprintf(fname, "/sys/class/net/%s/%s", dev, prop); fd = open(fname, O_RDONLY); if (fd < 0) { if (strcmp(prop, "tun_flags")) fprintf(stderr, "open %s: %s\n", fname, strerror(errno)); return -1; } len = read(fd, buf, sizeof(buf)-1); close(fd); if (len < 0) { fprintf(stderr, "read %s: %s", fname, strerror(errno)); return -1; } buf[len] = 0; result = strtol(buf, &endp, 0); if (*endp != '\n') { fprintf(stderr, "Failed to parse %s\n", fname); return -1; } *value = result; return 0; } static void print_flags(long flags) { if (flags & IFF_TUN) printf(" tun"); if (flags & IFF_TAP) printf(" tap"); if (!(flags & IFF_NO_PI)) printf(" pi"); if (flags & IFF_ONE_QUEUE) printf(" one_queue"); if (flags & IFF_VNET_HDR) printf(" vnet_hdr"); flags &= ~(IFF_TUN|IFF_TAP|IFF_NO_PI|IFF_ONE_QUEUE|IFF_VNET_HDR); if (flags) printf(" UNKNOWN_FLAGS:%lx", flags); } static int do_show(int argc, char **argv) { DIR *dir; struct dirent *d; long flags, owner = -1, group = -1; dir = opendir("/sys/class/net"); if (!dir) { perror("opendir"); return -1; } while ((d = readdir(dir))) { if (d->d_name[0] == '.' && (d->d_name[1] == 0 || d->d_name[1] == '.')) continue; if (read_prop(d->d_name, "tun_flags", &flags)) continue; read_prop(d->d_name, "owner", &owner); read_prop(d->d_name, "group", &group); printf("%s:", d->d_name); print_flags(flags); if (owner != -1) printf(" user %ld", owner); if (group != -1) printf(" group %ld", group); printf("\n"); } closedir(dir); return 0; } int do_iptuntap(int argc, char **argv) { if (argc > 0) { if (matches(*argv, "add") == 0) return do_add(argc-1, argv+1); if (matches(*argv, "delete") == 0) return do_del(argc-1, argv+1); if (matches(*argv, "show") == 0 || matches(*argv, "lst") == 0 || matches(*argv, "list") == 0) return do_show(argc-1, argv+1); if (matches(*argv, "help") == 0) usage(); } else return do_show(0, NULL); fprintf(stderr, "Command \"%s\" is unknown, try \"ip tuntap help\".\n", *argv); exit(-1); }