/*
* iplink.c "ip link".
*
* 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: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <syslog.h>
#include <fcntl.h>
#include <dlfcn.h>
#include <errno.h>
#include <sys/socket.h>
#include <linux/if.h>
#include <linux/if_packet.h>
#include <linux/if_ether.h>
#include <linux/sockios.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <sys/ioctl.h>
#include <linux/sockios.h>
#include "rt_names.h"
#include "utils.h"
#include "ip_common.h"
#define IPLINK_IOCTL_COMPAT 1
#ifndef LIBDIR
#define LIBDIR "/usr/lib/"
#endif
static void usage(void) __attribute__((noreturn));
static int iplink_have_newlink(void);
void iplink_usage(void)
{
if (iplink_have_newlink()) {
fprintf(stderr, "Usage: ip link add link DEV [ name ] NAME\n");
fprintf(stderr, " [ txqueuelen PACKETS ]\n");
fprintf(stderr, " [ address LLADDR ]\n");
fprintf(stderr, " [ broadcast LLADDR ]\n");
fprintf(stderr, " [ mtu MTU ]\n");
fprintf(stderr, " type TYPE [ ARGS ]\n");
fprintf(stderr, " ip link delete DEV type TYPE [ ARGS ]\n");
fprintf(stderr, "\n");
fprintf(stderr, " ip link set DEVICE [ { up | down } ]\n");
} else
fprintf(stderr, "Usage: ip link set DEVICE [ { up | down } ]\n");
fprintf(stderr, " [ arp { on | off } ]\n");
fprintf(stderr, " [ dynamic { on | off } ]\n");
fprintf(stderr, " [ multicast { on | off } ]\n");
fprintf(stderr, " [ allmulticast { on | off } ]\n");
fprintf(stderr, " [ promisc { on | off } ]\n");
fprintf(stderr, " [ trailers { on | off } ]\n");
fprintf(stderr, " [ txqueuelen PACKETS ]\n");
fprintf(stderr, " [ name NEWNAME ]\n");
fprintf(stderr, " [ address LLADDR ]\n");
fprintf(stderr, " [ broadcast LLADDR ]\n");
fprintf(stderr, " [ mtu MTU ]\n");
fprintf(stderr, " [ netns PID ]\n");
fprintf(stderr, " [ alias NAME ]\n");
fprintf(stderr, " ip link show [ DEVICE ]\n");
if (iplink_have_newlink()) {
fprintf(stderr, "\n");
fprintf(stderr, "TYPE := { vlan | veth | vcan | dummy | ifb | macvlan | can }\n");
}
exit(-1);
}
static void usage(void)
{
iplink_usage();
}
static int on_off(char *msg)
{
fprintf(stderr, "Error: argument of \"%s\" must be \"on\" or \"off\"\n", msg);
return -1;
}
static void *BODY; /* cached dlopen(NULL) handle */
static struct link_util *linkutil_list;
struct link_util *get_link_kind(const char *id)
{
void *dlh;
char buf[256];
struct link_util *l;
for (l = linkutil_list; l; l = l->next)
if (strcmp(l->id, id) == 0)
return l;
snprintf(buf, sizeof(buf), LIBDIR "/ip/link_%s.so", id);
dlh = dlopen(buf, RTLD_LAZY);
if (dlh == NULL) {
/* look in current binary, only open once */
dlh = BODY;
if (dlh == NULL) {
dlh = BODY = dlopen(NULL, RTLD_LAZY);
if (dlh == NULL)
return NULL;
}
}
snprintf(buf, sizeof(buf), "%s_link_util", id);
l = dlsym(dlh, buf);
if (l == NULL)
return NULL;
l->next = linkutil_list;
linkutil_list = l;
return l;
}
#if IPLINK_IOCTL_COMPAT
static int have_rtnl_newlink = -1;
static int accept_msg(const struct sockaddr_nl *who,
struct nlmsghdr *n, void *arg)
{
struct nlmsgerr *err = (struct nlmsgerr *)NLMSG_DATA(n);
if (n->nlmsg_type == NLMSG_ERROR &&
(err->error == -EOPNOTSUPP || err->error == -EINVAL))
have_rtnl_newlink = 0;
else
have_rtnl_newlink = 1;
return -1;
}
static int iplink_have_newlink(void)
{
struct {
struct nlmsghdr n;
struct ifinfomsg i;
char buf[1024];
} req;
if (have_rtnl_newlink < 0) {
memset(&req, 0, sizeof(req));
req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
req.n.nlmsg_flags = NLM_F_REQUEST|NLM_F_ACK;
req.n.nlmsg_type = RTM_NEWLINK;
req.i.ifi_family = AF_UNSPEC;
rtnl_send(&rth, (char *)&req.n, req.n.nlmsg_len);
rtnl_listen(&rth, accept_msg, NULL);
}
return have_rtnl_newlink;
}
#else /* IPLINK_IOCTL_COMPAT */
static int iplink_have_newlink(void)
{
return 1;
}
#endif /* ! IPLINK_IOCTL_COMPAT */
struct iplink_req {
struct nlmsghdr n;
struct ifinfomsg i;
char buf[1024];
};
int iplink_parse(int argc, char **argv, struct iplink_req *req,
char **name, char **type, char **link, char **dev)
{
int ret, len;
char abuf[32];
int qlen = -1;
int mtu = -1;
int netns = -1;
ret = argc;
while (argc > 0) {
if (strcmp(*argv, "up") == 0) {
req->i.ifi_change |= IFF_UP;
req->i.ifi_flags |= IFF_UP;
} else if (strcmp(*argv, "down") == 0) {
req->i.ifi_change |= IFF_UP;
req->i.ifi_flags &= ~IFF_UP;
} else if (strcmp(*argv, "name") == 0) {
NEXT_ARG();
*name = *argv;
} else if (matches(*argv, "link") == 0) {
NEXT_ARG();
*link = *argv;
} else if (matches(*argv, "address") == 0) {
NEXT_ARG();
len = ll_addr_a2n(abuf, sizeof(abuf), *argv);
if (len < 0)
return -1;
addattr_l(&req->n, sizeof(*req), IFLA_ADDRESS, abuf, len);
} else if (matches(*argv, "broadcast") == 0 ||
strcmp(*argv, "brd") == 0) {
NEXT_ARG();
len = ll_addr_a2n(abuf, sizeof(abuf), *argv);
if (len < 0)
return -1;
addattr_l(&req->n, sizeof(*req), IFLA_BROADCAST, abuf, len);
} else if (matches(*argv, "txqueuelen") == 0 ||
strcmp(*argv, "qlen") == 0 ||
matches(*argv, "txqlen") == 0) {
NEXT_ARG();
if (qlen != -1)
duparg("txqueuelen", *argv);
if (get_integer(&qlen, *argv, 0))
invarg("Invalid \"txqueuelen\" value\n", *argv);
addattr_l(&req->n, sizeof(*req), IFLA_TXQLEN, &qlen, 4);
} else if (strcmp(*argv, "mtu") == 0) {
NEXT_ARG();
if (mtu != -1)
duparg("mtu", *argv);
if (get_integer(&mtu, *argv, 0))
invarg("Invalid \"mtu\" value\n", *argv);
addattr_l(&req->n, sizeof(*req), IFLA_MTU, &mtu, 4);
} else if (strcmp(*argv, "netns") == 0) {
NEXT_ARG();
if (netns != -1)
duparg("netns", *argv);
if (get_integer(&netns, *argv, 0))
invarg("Invalid \"netns\" value\n", *argv);
addattr_l(&req->n, sizeof(*req), IFLA_NET_NS_PID, &netns, 4);
} else if (strcmp(*argv, "multicast") == 0) {
NEXT_ARG();
req->i.ifi_change |= IFF_MULTICAST;
if (strcmp(*argv, "on") == 0) {
req->i.ifi_flags |= IFF_MULTICAST;
} else if (strcmp(*argv, "off") == 0) {
req->i.ifi_flags &= ~IFF_MULTICAST;
} else
return on_off("multicast");
} else if (strcmp(*argv, "allmulticast") == 0) {
NEXT_ARG();
req->i.ifi_change |= IFF_ALLMULTI;
if (strcmp(*argv, "on") == 0) {
req->i.ifi_flags |= IFF_ALLMULTI;
} else if (strcmp(*argv, "off") == 0) {
req->i.ifi_flags &= ~IFF_ALLMULTI;
} else
return on_off("allmulticast");
} else if (strcmp(*argv, "promisc") == 0) {
NEXT_ARG();
req->i.ifi_change |= IFF_PROMISC;
if (strcmp(*argv, "on") == 0) {
req->i.ifi_flags |= IFF_PROMISC;
} else if (strcmp(*argv, "off") == 0) {
req->i.ifi_flags &= ~IFF_PROMISC;
} else
return on_off("promisc");
} else if (strcmp(*argv, "trailers") == 0) {
NEXT_ARG();
req->i.ifi_change |= IFF_NOTRAILERS;
if (strcmp(*argv, "off") == 0) {
req->i.ifi_flags |= IFF_NOTRAILERS;
} else if (strcmp(*argv, "on") == 0) {
req->i.ifi_flags &= ~IFF_NOTRAILERS;
} else
return on_off("trailers");
} else if (strcmp(*argv, "arp") == 0) {
NEXT_ARG();
req->i.ifi_change |= IFF_NOARP;
if (strcmp(*argv, "on") == 0) {
req->i.ifi_flags &= ~IFF_NOARP;
} else if (strcmp(*argv, "off") == 0) {
req->i.ifi_flags |= IFF_NOARP;
} else
return on_off("noarp");
#ifdef IFF_DYNAMIC
} else if (matches(*argv, "dynamic") == 0) {
NEXT_ARG();
req->i.ifi_change |= IFF_DYNAMIC;
if (strcmp(*argv, "on") == 0) {
req->i.ifi_flags |= IFF_DYNAMIC;
} else if (strcmp(*argv, "off") == 0) {
req->i.ifi_flags &= ~IFF_DYNAMIC;
} else
return on_off("dynamic");
#endif
} else if (matches(*argv, "type") == 0) {
NEXT_ARG();
*type = *argv;
argc--; argv++;
break;
} else if (matches(*argv, "alias") == 0) {
NEXT_ARG();
addattr_l(&req->n, sizeof(*req), IFLA_IFALIAS,
*argv, strlen(*argv));
argc--; argv++;
break;
} else {
if (strcmp(*argv, "dev") == 0) {
NEXT_ARG();
}
if (matches(*argv, "help") == 0)
usage();
if (*dev)
duparg2("dev", *argv);
*dev = *argv;
}
argc--; argv++;
}
return ret - argc;
}
static int iplink_modify(int cmd, unsigned int flags, int argc, char **argv)
{
int len;
char *dev = NULL;
char *name = NULL;
char *link = NULL;
char *type = NULL;
struct link_util *lu = NULL;
struct iplink_req req;
int ret;
memset(&req, 0, sizeof(req));
req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
req.n.nlmsg_flags = NLM_F_REQUEST|flags;
req.n.nlmsg_type = cmd;
req.i.ifi_family = preferred_family;
ret = iplink_parse(argc, argv, &req, &name, &type, &link, &dev);
if (ret < 0)
return ret;
argc -= ret;
argv += ret;
ll_init_map(&rth);
if (type) {
struct rtattr *linkinfo = NLMSG_TAIL(&req.n);
addattr_l(&req.n, sizeof(req), IFLA_LINKINFO, NULL, 0);
addattr_l(&req.n, sizeof(req), IFLA_INFO_KIND, type,
strlen(type));
lu = get_link_kind(type);
if (lu && argc) {
struct rtattr * data = NLMSG_TAIL(&req.n);
addattr_l(&req.n, sizeof(req), IFLA_INFO_DATA, NULL, 0);
if (lu->parse_opt &&
lu->parse_opt(lu, argc, argv, &req.n))
return -1;
data->rta_len = (void *)NLMSG_TAIL(&req.n) - (void *)data;
} else if (argc) {
if (matches(*argv, "help") == 0)
usage();
fprintf(stderr, "Garbage instead of arguments \"%s ...\". "
"Try \"ip link help\".\n", *argv);
return -1;
}
linkinfo->rta_len = (void *)NLMSG_TAIL(&req.n) - (void *)linkinfo;
} else if (flags & NLM_F_CREATE) {
fprintf(stderr, "Not enough information: \"type\" argument "
"is required\n");
return -1;
}
if (!(flags & NLM_F_CREATE)) {
if (!dev) {
fprintf(stderr, "Not enough information: \"dev\" "
"argument is required.\n");
exit(-1);
}
req.i.ifi_index = ll_name_to_index(dev);
if (req.i.ifi_index == 0) {
fprintf(stderr, "Cannot find device \"%s\"\n", dev);
return -1;
}
} else {
/* Allow "ip link add dev" and "ip link add name" */
if (!name)
name = dev;
if (link) {
int ifindex;
ifindex = ll_name_to_index(link);
if (ifindex == 0) {
fprintf(stderr, "Cannot find device \"%s\"\n",
link);
return -1;
}
addattr_l(&req.n, sizeof(req), IFLA_LINK, &ifindex, 4);
}
}
if (name) {
len = strlen(name) + 1;
if (len == 1)
invarg("\"\" is not a valid device identifier\n", "name");
if (len > IFNAMSIZ)
invarg("\"name\" too long\n", name);
addattr_l(&req.n, sizeof(req), IFLA_IFNAME, name, len);
}
if (rtnl_talk(&rth, &req.n, 0, 0, NULL, NULL, NULL) < 0)
exit(2);
return 0;
}
#if IPLINK_IOCTL_COMPAT
static int get_ctl_fd(void)
{
int s_errno;
int fd;
fd = socket(PF_INET, SOCK_DGRAM, 0);
if (fd >= 0)
return fd;
s_errno = errno;
fd = socket(PF_PACKET, SOCK_DGRAM, 0);
if (fd >= 0)
return fd;
fd = socket(PF_INET6, SOCK_DGRAM, 0);
if (fd >= 0)
return fd;
errno = s_errno;
perror("Cannot create control socket");
return -1;
}
static int do_chflags(const char *dev, __u32 flags, __u32 mask)
{
struct ifreq ifr;
int fd;
int err;
strncpy(ifr.ifr_name, dev, IFNAMSIZ);
fd = get_ctl_fd();
if (fd < 0)
return -1;
err = ioctl(fd, SIOCGIFFLAGS, &ifr);
if (err) {
perror("SIOCGIFFLAGS");
close(fd);
return -1;
}
if ((ifr.ifr_flags^flags)&mask) {
ifr.ifr_flags &= ~mask;
ifr.ifr_flags |= mask&flags;
err = ioctl(fd, SIOCSIFFLAGS, &ifr);
if (err)
perror("SIOCSIFFLAGS");
}
close(fd);
return err;
}
static int do_changename(const char *dev, const char *newdev)
{
struct ifreq ifr;
int fd;
int err;
strncpy(ifr.ifr_name, dev, IFNAMSIZ);
strncpy(ifr.ifr_newname, newdev, IFNAMSIZ);
fd = get_ctl_fd();
if (fd < 0)
return -1;
err = ioctl(fd, SIOCSIFNAME, &ifr);
if (err) {
perror("SIOCSIFNAME");
close(fd);
return -1;
}
close(fd);
return err;
}
static int set_qlen(const char *dev, int qlen)
{
struct ifreq ifr;
int s;
s = get_ctl_fd();
if (s < 0)
return -1;
memset(&ifr, 0, sizeof(ifr));
strncpy(ifr.ifr_name, dev, IFNAMSIZ);
ifr.ifr_qlen = qlen;
if (ioctl(s, SIOCSIFTXQLEN, &ifr) < 0) {
perror("SIOCSIFXQLEN");
close(s);
return -1;
}
close(s);
return 0;
}
static int set_mtu(const char *dev, int mtu)
{
struct ifreq ifr;
int s;
s = get_ctl_fd();
if (s < 0)
return -1;
memset(&ifr, 0, sizeof(ifr));
strncpy(ifr.ifr_name, dev, IFNAMSIZ);
ifr.ifr_mtu = mtu;
if (ioctl(s, SIOCSIFMTU, &ifr) < 0) {
perror("SIOCSIFMTU");
close(s);
return -1;
}
close(s);
return 0;
}
static int get_address(const char *dev, int *htype)
{
struct ifreq ifr;
struct sockaddr_ll me;
socklen_t alen;
int s;
s = socket(PF_PACKET, SOCK_DGRAM, 0);
if (s < 0) {
perror("socket(PF_PACKET)");
return -1;
}
memset(&ifr, 0, sizeof(ifr));
strncpy(ifr.ifr_name, dev, IFNAMSIZ);
if (ioctl(s, SIOCGIFINDEX, &ifr) < 0) {
perror("SIOCGIFINDEX");
close(s);
return -1;
}
memset(&me, 0, sizeof(me));
me.sll_family = AF_PACKET;
me.sll_ifindex = ifr.ifr_ifindex;
me.sll_protocol = htons(ETH_P_LOOP);
if (bind(s, (struct sockaddr*)&me, sizeof(me)) == -1) {
perror("bind");
close(s);
return -1;
}
alen = sizeof(me);
if (getsockname(s, (struct sockaddr*)&me, &alen) == -1) {
perror("getsockname");
close(s);
return -1;
}
close(s);
*htype = me.sll_hatype;
return me.sll_halen;
}
static int parse_address(const char *dev, int hatype, int halen,
char *lla, struct ifreq *ifr)
{
int alen;
memset(ifr, 0, sizeof(*ifr));
strncpy(ifr->ifr_name, dev, IFNAMSIZ);
ifr->ifr_hwaddr.sa_family = hatype;
alen = ll_addr_a2n(ifr->ifr_hwaddr.sa_data, 14, lla);
if (alen < 0)
return -1;
if (alen != halen) {
fprintf(stderr, "Wrong address (%s) length: expected %d bytes\n", lla, halen);
return -1;
}
return 0;
}
static int set_address(struct ifreq *ifr, int brd)
{
int s;
s = get_ctl_fd();
if (s < 0)
return -1;
if (ioctl(s, brd?SIOCSIFHWBROADCAST:SIOCSIFHWADDR, ifr) < 0) {
perror(brd?"SIOCSIFHWBROADCAST":"SIOCSIFHWADDR");
close(s);
return -1;
}
close(s);
return 0;
}
static int do_set(int argc, char **argv)
{
char *dev = NULL;
__u32 mask = 0;
__u32 flags = 0;
int qlen = -1;
int mtu = -1;
char *newaddr = NULL;
char *newbrd = NULL;
struct ifreq ifr0, ifr1;
char *newname = NULL;
int htype, halen;
while (argc > 0) {
if (strcmp(*argv, "up") == 0) {
mask |= IFF_UP;
flags |= IFF_UP;
} else if (strcmp(*argv, "down") == 0) {
mask |= IFF_UP;
flags &= ~IFF_UP;
} else if (strcmp(*argv, "name") == 0) {
NEXT_ARG();
newname = *argv;
} else if (matches(*argv, "address") == 0) {
NEXT_ARG();
newaddr = *argv;
} else if (matches(*argv, "broadcast") == 0 ||
strcmp(*argv, "brd") == 0) {
NEXT_ARG();
newbrd = *argv;
} else if (matches(*argv, "txqueuelen") == 0 ||
strcmp(*argv, "qlen") == 0 ||
matches(*argv, "txqlen") == 0) {
NEXT_ARG();
if (qlen != -1)
duparg("txqueuelen", *argv);
if (get_integer(&qlen, *argv, 0))
invarg("Invalid \"txqueuelen\" value\n", *argv);
} else if (strcmp(*argv, "mtu") == 0) {
NEXT_ARG();
if (mtu != -1)
duparg("mtu", *argv);
if (get_integer(&mtu, *argv, 0))
invarg("Invalid \"mtu\" value\n", *argv);
} else if (strcmp(*argv, "multicast") == 0) {
NEXT_ARG();
mask |= IFF_MULTICAST;
if (strcmp(*argv, "on") == 0) {
flags |= IFF_MULTICAST;
} else if (strcmp(*argv, "off") == 0) {
flags &= ~IFF_MULTICAST;
} else
return on_off("multicast");
} else if (strcmp(*argv, "allmulticast") == 0) {
NEXT_ARG();
mask |= IFF_ALLMULTI;
if (strcmp(*argv, "on") == 0) {
flags |= IFF_ALLMULTI;
} else if (strcmp(*argv, "off") == 0) {
flags &= ~IFF_ALLMULTI;
} else
return on_off("allmulticast");
} else if (strcmp(*argv, "promisc") == 0) {
NEXT_ARG();
mask |= IFF_PROMISC;
if (strcmp(*argv, "on") == 0) {
flags |= IFF_PROMISC;
} else if (strcmp(*argv, "off") == 0) {
flags &= ~IFF_PROMISC;
} else
return on_off("promisc");
} else if (strcmp(*argv, "trailers") == 0) {
NEXT_ARG();
mask |= IFF_NOTRAILERS;
if (strcmp(*argv, "off") == 0) {
flags |= IFF_NOTRAILERS;
} else if (strcmp(*argv, "on") == 0) {
flags &= ~IFF_NOTRAILERS;
} else
return on_off("trailers");
} else if (strcmp(*argv, "arp") == 0) {
NEXT_ARG();
mask |= IFF_NOARP;
if (strcmp(*argv, "on") == 0) {
flags &= ~IFF_NOARP;
} else if (strcmp(*argv, "off") == 0) {
flags |= IFF_NOARP;
} else
return on_off("noarp");
#ifdef IFF_DYNAMIC
} else if (matches(*argv, "dynamic") == 0) {
NEXT_ARG();
mask |= IFF_DYNAMIC;
if (strcmp(*argv, "on") == 0) {
flags |= IFF_DYNAMIC;
} else if (strcmp(*argv, "off") == 0) {
flags &= ~IFF_DYNAMIC;
} else
return on_off("dynamic");
#endif
} else {
if (strcmp(*argv, "dev") == 0) {
NEXT_ARG();
}
if (matches(*argv, "help") == 0)
usage();
if (dev)
duparg2("dev", *argv);
dev = *argv;
}
argc--; argv++;
}
if (!dev) {
fprintf(stderr, "Not enough of information: \"dev\" argument is required.\n");
exit(-1);
}
if (newaddr || newbrd) {
halen = get_address(dev, &htype);
if (halen < 0)
return -1;
if (newaddr) {
if (parse_address(dev, htype, halen, newaddr, &ifr0) < 0)
return -1;
}
if (newbrd) {
if (parse_address(dev, htype, halen, newbrd, &ifr1) < 0)
return -1;
}
}
if (newname && strcmp(dev, newname)) {
if (strlen(newname) == 0)
invarg("\"\" is not a valid device identifier\n", "name");
if (do_changename(dev, newname) < 0)
return -1;
dev = newname;
}
if (qlen != -1) {
if (set_qlen(dev, qlen) < 0)
return -1;
}
if (mtu != -1) {
if (set_mtu(dev, mtu) < 0)
return -1;
}
if (newaddr || newbrd) {
if (newbrd) {
if (set_address(&ifr1, 1) < 0)
return -1;
}
if (newaddr) {
if (set_address(&ifr0, 0) < 0)
return -1;
}
}
if (mask)
return do_chflags(dev, flags, mask);
return 0;
}
#endif /* IPLINK_IOCTL_COMPAT */
int do_iplink(int argc, char **argv)
{
if (argc > 0) {
if (iplink_have_newlink()) {
if (matches(*argv, "add") == 0)
return iplink_modify(RTM_NEWLINK,
NLM_F_CREATE|NLM_F_EXCL,
argc-1, argv+1);
if (matches(*argv, "set") == 0 ||
matches(*argv, "change") == 0)
return iplink_modify(RTM_NEWLINK, 0,
argc-1, argv+1);
if (matches(*argv, "replace") == 0)
return iplink_modify(RTM_NEWLINK,
NLM_F_CREATE|NLM_F_REPLACE,
argc-1, argv+1);
if (matches(*argv, "delete") == 0)
return iplink_modify(RTM_DELLINK, 0,
argc-1, argv+1);
} else {
#if IPLINK_IOCTL_COMPAT
if (matches(*argv, "set") == 0)
return do_set(argc-1, argv+1);
#endif
}
if (matches(*argv, "show") == 0 ||
matches(*argv, "lst") == 0 ||
matches(*argv, "list") == 0)
return ipaddr_list_link(argc-1, argv+1);
if (matches(*argv, "help") == 0)
usage();
} else
return ipaddr_list_link(0, NULL);
fprintf(stderr, "Command \"%s\" is unknown, try \"ip link help\".\n", *argv);
exit(-1);
}