/*
 * 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 <stdbool.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 ] [index IDX ]\n");
		fprintf(stderr, "                   [ numtxqueues QUEUE_COUNT ]\n");
		fprintf(stderr, "                   [ numrxqueues QUEUE_COUNT ]\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 { dev DEVICE | group DEVGROUP } [ { 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, "	                  [ netns NAME ]\n");
	fprintf(stderr, "			  [ alias NAME ]\n");
	fprintf(stderr, "	                  [ vf NUM [ mac LLADDR ]\n");
	fprintf(stderr, "				   [ vlan VLANID [ qos VLAN-QOS ] ]\n");

	fprintf(stderr, "				   [ rate TXRATE ] ] \n");

	fprintf(stderr, "				   [ spoofchk { on | off} ] ] \n");
	fprintf(stderr, "				   [ state { auto | enable | disable} ] ]\n");
	fprintf(stderr, "			  [ master DEVICE ]\n");
	fprintf(stderr, "			  [ nomaster ]\n");
	fprintf(stderr, "			  [ addrgenmode { eui64 | none } ]\n");
	fprintf(stderr, "       ip link show [ DEVICE | group GROUP ] [up] [master DEV] [type TYPE]\n");

	if (iplink_have_newlink()) {
		fprintf(stderr, "       ip link help [ TYPE ]\n");
		fprintf(stderr, "\n");
		fprintf(stderr, "TYPE := { vlan | veth | vcan | dummy | ifb | macvlan | macvtap |\n");
		fprintf(stderr, "          bridge | bond | ipoib | ip6tnl | ipip | sit | vxlan |\n");
		fprintf(stderr, "          gre | gretap | ip6gre | ip6gretap | vti | nlmon |\n");
		fprintf(stderr, "          bond_slave }\n");
	}
	exit(-1);
}

static void usage(void)
{
	iplink_usage();
}

static int on_off(const char *msg, const char *realval)
{
	fprintf(stderr, "Error: argument of \"%s\" must be \"on\" or \"off\", not \"%s\"\n", msg, realval);
	return -1;
}

static void *BODY;		/* cached dlopen(NULL) handle */
static struct link_util *linkutil_list;

static struct link_util *__get_link_kind(const char *id, bool slave)
{
	void *dlh;
	char buf[256];
	struct link_util *l;

	for (l = linkutil_list; l; l = l->next)
		if (strcmp(l->id, id) == 0 &&
		    l->slave == slave)
			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;
		}
	}

	if (slave)
		snprintf(buf, sizeof(buf), "%s_slave_link_util", id);
	else
		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;
}

struct link_util *get_link_kind(const char *id)
{
	return __get_link_kind(id, false);
}

struct link_util *get_link_slave_kind(const char *id)
{
	return __get_link_kind(id, true);
}

static int get_link_mode(const char *mode)
{
	if (strcasecmp(mode, "default") == 0)
		return IF_LINK_MODE_DEFAULT;
	if (strcasecmp(mode, "dormant") == 0)
		return IF_LINK_MODE_DORMANT;
	return -1;
}

static int get_addr_gen_mode(const char *mode)
{
	if (strcasecmp(mode, "eui64") == 0)
		return IN6_ADDR_GEN_MODE_EUI64;
	if (strcasecmp(mode, "none") == 0)
		return IN6_ADDR_GEN_MODE_NONE;
	return -1;
}

#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;

		if (rtnl_send(&rth, &req.n, req.n.nlmsg_len) < 0) {
			perror("request send failed");
			exit(1);
		}
		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];
};

static int iplink_parse_vf(int vf, int *argcp, char ***argvp,
			   struct iplink_req *req, int dev_index)
{
	char new_rate_api = 0, count = 0, override_legacy_rate = 0;
	struct ifla_vf_rate tivt;
	int len, argc = *argcp;
	char **argv = *argvp;
	struct rtattr *vfinfo;

	tivt.min_tx_rate = -1;
	tivt.max_tx_rate = -1;

	vfinfo = addattr_nest(&req->n, sizeof(*req), IFLA_VF_INFO);

	while (NEXT_ARG_OK()) {
		NEXT_ARG();
		count++;
		if (!matches(*argv, "max_tx_rate")) {
			/* new API in use */
			new_rate_api = 1;
			/* override legacy rate */
			override_legacy_rate = 1;
		} else if (!matches(*argv, "min_tx_rate")) {
			/* new API in use */
			new_rate_api = 1;
		}
	}

	while (count--) {
		/* rewind arg */
		PREV_ARG();
	}

	while (NEXT_ARG_OK()) {
		NEXT_ARG();
		if (matches(*argv, "mac") == 0) {
			struct ifla_vf_mac ivm;
			NEXT_ARG();
			ivm.vf = vf;
			len = ll_addr_a2n((char *)ivm.mac, 32, *argv);
			if (len < 0)
				return -1;
			addattr_l(&req->n, sizeof(*req), IFLA_VF_MAC, &ivm, sizeof(ivm));
		} else if (matches(*argv, "vlan") == 0) {
			struct ifla_vf_vlan ivv;
			NEXT_ARG();
			if (get_unsigned(&ivv.vlan, *argv, 0)) {
				invarg("Invalid \"vlan\" value\n", *argv);
			}
			ivv.vf = vf;
			ivv.qos = 0;
			if (NEXT_ARG_OK()) {
				NEXT_ARG();
				if (matches(*argv, "qos") == 0) {
					NEXT_ARG();
					if (get_unsigned(&ivv.qos, *argv, 0)) {
						invarg("Invalid \"qos\" value\n", *argv);
					}
				} else {
					/* rewind arg */
					PREV_ARG();
				}
			}
			addattr_l(&req->n, sizeof(*req), IFLA_VF_VLAN, &ivv, sizeof(ivv));
		} else if (matches(*argv, "rate") == 0) {
			struct ifla_vf_tx_rate ivt;
			NEXT_ARG();
			if (get_unsigned(&ivt.rate, *argv, 0)) {
				invarg("Invalid \"rate\" value\n", *argv);
			}
			ivt.vf = vf;
			if (!new_rate_api)
				addattr_l(&req->n, sizeof(*req),
					  IFLA_VF_TX_RATE, &ivt, sizeof(ivt));
			else if (!override_legacy_rate)
				tivt.max_tx_rate = ivt.rate;

		} else if (matches(*argv, "max_tx_rate") == 0) {
			NEXT_ARG();
			if (get_unsigned(&tivt.max_tx_rate, *argv, 0))
				invarg("Invalid \"max tx rate\" value\n",
				       *argv);
			tivt.vf = vf;

		} else if (matches(*argv, "min_tx_rate") == 0) {
			NEXT_ARG();
			if (get_unsigned(&tivt.min_tx_rate, *argv, 0))
				invarg("Invalid \"min tx rate\" value\n",
				       *argv);
			tivt.vf = vf;

		} else if (matches(*argv, "spoofchk") == 0) {
			struct ifla_vf_spoofchk ivs;
			NEXT_ARG();
			if (matches(*argv, "on") == 0)
				ivs.setting = 1;
			else if (matches(*argv, "off") == 0)
				ivs.setting = 0;
			else
				invarg("Invalid \"spoofchk\" value\n", *argv);
			ivs.vf = vf;
			addattr_l(&req->n, sizeof(*req), IFLA_VF_SPOOFCHK, &ivs, sizeof(ivs));

		} else if (matches(*argv, "state") == 0) {
			struct ifla_vf_link_state ivl;
			NEXT_ARG();
			if (matches(*argv, "auto") == 0)
				ivl.link_state = IFLA_VF_LINK_STATE_AUTO;
			else if (matches(*argv, "enable") == 0)
				ivl.link_state = IFLA_VF_LINK_STATE_ENABLE;
			else if (matches(*argv, "disable") == 0)
				ivl.link_state = IFLA_VF_LINK_STATE_DISABLE;
			else
				invarg("Invalid \"state\" value\n", *argv);
			ivl.vf = vf;
			addattr_l(&req->n, sizeof(*req), IFLA_VF_LINK_STATE, &ivl, sizeof(ivl));
		} else {
			/* rewind arg */
			PREV_ARG();
			break;
		}
	}

	if (new_rate_api) {
		int tmin, tmax;

		if (tivt.min_tx_rate == -1 || tivt.max_tx_rate == -1) {
			ipaddr_get_vf_rate(tivt.vf, &tmin, &tmax, dev_index);
			if (tivt.min_tx_rate == -1)
				tivt.min_tx_rate = tmin;
			if (tivt.max_tx_rate == -1)
				tivt.max_tx_rate = tmax;
		}
		addattr_l(&req->n, sizeof(*req), IFLA_VF_RATE, &tivt,
			  sizeof(tivt));
	}

	if (argc == *argcp)
		incomplete_command();

	addattr_nest_end(&req->n, vfinfo);

	*argcp = argc;
	*argvp = argv;
	return 0;
}

int iplink_parse(int argc, char **argv, struct iplink_req *req,
		char **name, char **type, char **link, char **dev, int *group, int *index)
{
	int ret, len;
	char abuf[32];
	int qlen = -1;
	int mtu = -1;
	int netns = -1;
	int vf = -1;
	int numtxqueues = -1;
	int numrxqueues = -1;
	int dev_index = 0;

	*group = -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 (strcmp(*argv, "index") == 0) {
			NEXT_ARG();
			*index = atoi(*argv);
			if (*index < 0)
				invarg("Invalid \"index\" value", *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 ((netns = get_netns_fd(*argv)) >= 0)
				addattr_l(&req->n, sizeof(*req), IFLA_NET_NS_FD, &netns, 4);
			else if (get_integer(&netns, *argv, 0) == 0)
				addattr_l(&req->n, sizeof(*req), IFLA_NET_NS_PID, &netns, 4);
			else
				invarg("Invalid \"netns\" value\n", *argv);
		} 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", *argv);
		} 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", *argv);
		} 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", *argv);
		} 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", *argv);
		} 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", *argv);
		} else if (strcmp(*argv, "vf") == 0) {
			struct rtattr *vflist;
			NEXT_ARG();
			if (get_integer(&vf,  *argv, 0)) {
				invarg("Invalid \"vf\" value\n", *argv);
			}
			vflist = addattr_nest(&req->n, sizeof(*req),
					      IFLA_VFINFO_LIST);
			if (dev_index == 0)
				missarg("dev");

			len = iplink_parse_vf(vf, &argc, &argv, req, dev_index);
			if (len < 0)
				return -1;
			addattr_nest_end(&req->n, vflist);
		} else if (matches(*argv, "master") == 0) {
			int ifindex;
			NEXT_ARG();
			ifindex = ll_name_to_index(*argv);
			if (!ifindex)
				invarg("Device does not exist\n", *argv);
			addattr_l(&req->n, sizeof(*req), IFLA_MASTER,
				  &ifindex, 4);
		} else if (matches(*argv, "nomaster") == 0) {
			int ifindex = 0;
			addattr_l(&req->n, sizeof(*req), IFLA_MASTER,
				  &ifindex, 4);
		} 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", *argv);
		} 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, "group") == 0) {
			NEXT_ARG();
			if (*group != -1)
				duparg("group", *argv);
			if (rtnl_group_a2n(group, *argv))
				invarg("Invalid \"group\" value\n", *argv);
		} else if (strcmp(*argv, "mode") == 0) {
			int mode;
			NEXT_ARG();
			mode = get_link_mode(*argv);
			if (mode < 0)
				invarg("Invalid link mode\n", *argv);
			addattr8(&req->n, sizeof(*req), IFLA_LINKMODE, mode);
		} else if (strcmp(*argv, "state") == 0) {
			int state;
			NEXT_ARG();
			state = get_operstate(*argv);
			if (state < 0)
				invarg("Invalid operstate\n", *argv);

			addattr8(&req->n, sizeof(*req), IFLA_OPERSTATE, state);
		} else if (matches(*argv, "numtxqueues") == 0) {
			NEXT_ARG();
			if (numtxqueues != -1)
				duparg("numtxqueues", *argv);
			if (get_integer(&numtxqueues, *argv, 0))
				invarg("Invalid \"numtxqueues\" value\n", *argv);
			addattr_l(&req->n, sizeof(*req), IFLA_NUM_TX_QUEUES,
				  &numtxqueues, 4);
		} else if (matches(*argv, "numrxqueues") == 0) {
			NEXT_ARG();
			if (numrxqueues != -1)
				duparg("numrxqueues", *argv);
			if (get_integer(&numrxqueues, *argv, 0))
				invarg("Invalid \"numrxqueues\" value\n", *argv);
			addattr_l(&req->n, sizeof(*req), IFLA_NUM_RX_QUEUES,
				  &numrxqueues, 4);
		} else if (matches(*argv, "addrgenmode") == 0) {
			struct rtattr *afs, *afs6;
			int mode;
			NEXT_ARG();
			mode = get_addr_gen_mode(*argv);
			if (mode < 0)
				invarg("Invalid address generation mode\n", *argv);
			afs = addattr_nest(&req->n, sizeof(*req), IFLA_AF_SPEC);
			afs6 = addattr_nest(&req->n, sizeof(*req), AF_INET6);
			addattr8(&req->n, sizeof(*req), IFLA_INET6_ADDR_GEN_MODE, mode);
			addattr_nest_end(&req->n, afs6);
			addattr_nest_end(&req->n, afs);
		} else {
			if (strcmp(*argv, "dev") == 0) {
				NEXT_ARG();
			}
			if (matches(*argv, "help") == 0)
				usage();
			if (*dev)
				duparg2("dev", *argv);
			*dev = *argv;
			dev_index = ll_name_to_index(*dev);
		}
		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;
	int index = -1;
	int group;
	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, &group, &index);
	if (ret < 0)
		return ret;

	argc -= ret;
	argv += ret;

	if (group != -1) {
		if (dev)
			addattr_l(&req.n, sizeof(req), IFLA_GROUP,
					&group, sizeof(group));
		else {
			if (argc) {
				fprintf(stderr, "Garbage instead of arguments "
						"\"%s ...\". Try \"ip link "
						"help\".\n", *argv);
				return -1;
			}
			if (flags & NLM_F_CREATE) {
				fprintf(stderr, "group cannot be used when "
						"creating devices.\n");
				return -1;
			}

			req.i.ifi_index = 0;
			addattr32(&req.n, sizeof(req), IFLA_GROUP, group);
			if (rtnl_talk(&rth, &req.n, 0, 0, NULL) < 0)
				exit(2);
			return 0;
		}
	}

	if (!(flags & NLM_F_CREATE)) {
		if (!dev) {
			fprintf(stderr, "Not enough information: \"dev\" "
					"argument is required.\n");
			exit(-1);
		}
		if (cmd == RTM_NEWLINK && index != -1) {
			fprintf(stderr, "index can be used only when "
					"creating devices.\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 (index == -1)
			req.i.ifi_index = 0;
		else
			req.i.ifi_index = index;
	}

	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 (type) {
		struct rtattr *linkinfo = NLMSG_TAIL(&req.n);
		char slavebuf[128], *ulinep = strchr(type, '_');
		int iflatype;

		addattr_l(&req.n, sizeof(req), IFLA_LINKINFO, NULL, 0);
		addattr_l(&req.n, sizeof(req), IFLA_INFO_KIND, type,
			 strlen(type));

		if (ulinep && !strcmp(ulinep, "_slave")) {
			strncpy(slavebuf, type, sizeof(slavebuf));
			slavebuf[sizeof(slavebuf) - 1] = '\0';
			ulinep = strchr(slavebuf, '_');
			/* check in case it was after sizeof(slavebuf) - 1*/
			if (ulinep)
				*ulinep = '\0';
			lu = get_link_slave_kind(slavebuf);
			iflatype = IFLA_INFO_SLAVE_DATA;
		} else {
			lu = get_link_kind(type);
			iflatype = IFLA_INFO_DATA;
		}
		if (lu && argc) {
			struct rtattr * data = NLMSG_TAIL(&req.n);
			addattr_l(&req.n, sizeof(req), iflatype, 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 (rtnl_talk(&rth, &req.n, 0, 0, NULL) < 0)
		exit(2);

	return 0;
}

int iplink_get(unsigned int flags, char *name, __u32 filt_mask)
{
	int len;
	struct iplink_req req;
	char answer[16384];

	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 = RTM_GETLINK;
	req.i.ifi_family = preferred_family;

	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);
	}
	addattr32(&req.n, sizeof(req), IFLA_EXT_MASK, filt_mask);

	if (rtnl_talk(&rth, &req.n, 0, 0, (struct nlmsghdr *)answer) < 0)
		return -2;

	print_linkinfo(NULL, (struct nlmsghdr *)answer, stdout);

	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", *argv);
		} 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", *argv);
		} 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", *argv);
		} 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", *argv);
		} 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", *argv);
		} 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", *argv);
		} 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 */

static void do_help(int argc, char **argv)
{
	struct link_util *lu = NULL;

	if (argc <= 0) {
		usage();
		return ;
	}

	lu = get_link_kind(*argv);

	if (lu && lu->print_help)
		lu->print_help(lu, argc-1, argv+1, stdout);
	else
		usage();
}

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) {
			do_help(argc-1, argv+1);
			return 0;
		}
	} else
		return ipaddr_list_link(0, NULL);

	fprintf(stderr, "Command \"%s\" is unknown, try \"ip link help\".\n", *argv);
	exit(-1);
}
