blob: 451f7f0eac6bbd95709057ca018563072be469f4 [file] [log] [blame]
/*
* 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 <David.Woodhouse@intel.com>
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <sys/ioctl.h>
#include <linux/if.h>
#include <linux/if_tun.h>
#include <pwd.h>
#include <grp.h>
#include <fcntl.h>
#include <dirent.h>
#include <errno.h>
#include <glob.h>
#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 | show | list | lst | help } [ dev PHYS_DEV ]\n");
fprintf(stderr, " [ mode { tun | tap } ] [ user USER ] [ group GROUP ]\n");
fprintf(stderr, " [ one_queue ] [ pi ] [ vnet_hdr ] [ multi_queue ] [ name NAME ]\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++;
}
if (!(ifr->ifr_flags & TUN_TYPE_MASK)) {
fprintf(stderr, "You failed to specify a tunnel mode\n");
return -1;
}
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;
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 char *pid_name(pid_t pid)
{
char *comm;
FILE *f;
int err;
err = asprintf(&comm, "/proc/%d/comm", pid);
if (err < 0)
return NULL;
f = fopen(comm, "r");
free(comm);
if (!f) {
perror("fopen");
return NULL;
}
if (fscanf(f, "%ms\n", &comm) != 1) {
perror("fscanf");
comm = NULL;
}
if (fclose(f))
perror("fclose");
return comm;
}
static void show_processes(const char *name)
{
glob_t globbuf = { };
char **fd_path;
int err;
err = glob("/proc/[0-9]*/fd/[0-9]*", GLOB_NOSORT,
NULL, &globbuf);
if (err)
return;
fd_path = globbuf.gl_pathv;
while (*fd_path) {
const char *dev_net_tun = "/dev/net/tun";
const size_t linkbuf_len = strlen(dev_net_tun) + 2;
char linkbuf[linkbuf_len], *fdinfo;
int pid, fd;
FILE *f;
if (sscanf(*fd_path, "/proc/%d/fd/%d", &pid, &fd) != 2)
goto next;
if (pid == getpid())
goto next;
err = readlink(*fd_path, linkbuf, linkbuf_len - 1);
if (err < 0) {
perror("readlink");
goto next;
}
linkbuf[err] = '\0';
if (strcmp(dev_net_tun, linkbuf))
goto next;
if (asprintf(&fdinfo, "/proc/%d/fdinfo/%d", pid, fd) < 0)
goto next;
f = fopen(fdinfo, "r");
free(fdinfo);
if (!f) {
perror("fopen");
goto next;
}
while (!feof(f)) {
char *key = NULL, *value = NULL;
err = fscanf(f, "%m[^:]: %ms\n", &key, &value);
if (err == EOF) {
if (ferror(f))
perror("fscanf");
break;
} else if (err == 2 &&
!strcmp("iff", key) &&
!strcmp(name, value)) {
char *pname = pid_name(pid);
printf(" %s(%d)", pname ? : "<NULL>", pid);
free(pname);
}
free(key);
free(value);
}
if (fclose(f))
perror("fclose");
next:
++fd_path;
}
globfree(&globbuf);
}
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");
if (show_details) {
printf("\tAttached to processes:");
show_processes(d->d_name);
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);
}