networking/libiproute/iplink.c - codeaurora/busybox - Gitiles

 /* vi: set sw=4 ts=4: */
 /*
  * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  *
  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
 #include <net/if.h>
 #include <net/if_packet.h>
 #include <netpacket/packet.h>
 #include <net/ethernet.h>

 #include "ip_common.h"  /* #include "libbb.h" is inside */
 #include "rt_names.h"
 #include "utils.h"

 #ifndef IFLA_LINKINFO
 # define IFLA_LINKINFO 18
 # define IFLA_INFO_KIND 1
 #endif

 /* taken from linux/sockios.h */
 #define SIOCSIFNAME  0x8923  /* set interface name */

 /* Exits on error */
 static int get_ctl_fd(void)
 {
 	int fd;

 	fd = socket(PF_INET, SOCK_DGRAM, 0);
 	if (fd >= 0)
 		return fd;
 	fd = socket(PF_PACKET, SOCK_DGRAM, 0);
 	if (fd >= 0)
 		return fd;
 	return xsocket(PF_INET6, SOCK_DGRAM, 0);
 }

 /* Exits on error */
 static void do_chflags(char *dev, uint32_t flags, uint32_t mask)
 {
 	struct ifreq ifr;
 	int fd;

 	strncpy_IFNAMSIZ(ifr.ifr_name, dev);
 	fd = get_ctl_fd();
 	xioctl(fd, SIOCGIFFLAGS, &ifr);
 	if ((ifr.ifr_flags ^ flags) & mask) {
 		ifr.ifr_flags &= ~mask;
 		ifr.ifr_flags |= mask & flags;
 		xioctl(fd, SIOCSIFFLAGS, &ifr);
 	}
 	close(fd);
 }

 /* Exits on error */
 static void do_changename(char *dev, char *newdev)
 {
 	struct ifreq ifr;
 	int fd;

 	strncpy_IFNAMSIZ(ifr.ifr_name, dev);
 	strncpy_IFNAMSIZ(ifr.ifr_newname, newdev);
 	fd = get_ctl_fd();
 	xioctl(fd, SIOCSIFNAME, &ifr);
 	close(fd);
 }

 /* Exits on error */
 static void set_qlen(char *dev, int qlen)
 {
 	struct ifreq ifr;
 	int s;

 	s = get_ctl_fd();
 	memset(&ifr, 0, sizeof(ifr));
 	strncpy_IFNAMSIZ(ifr.ifr_name, dev);
 	ifr.ifr_qlen = qlen;
 	xioctl(s, SIOCSIFTXQLEN, &ifr);
 	close(s);
 }

 /* Exits on error */
 static void set_mtu(char *dev, int mtu)
 {
 	struct ifreq ifr;
 	int s;

 	s = get_ctl_fd();
 	memset(&ifr, 0, sizeof(ifr));
 	strncpy_IFNAMSIZ(ifr.ifr_name, dev);
 	ifr.ifr_mtu = mtu;
 	xioctl(s, SIOCSIFMTU, &ifr);
 	close(s);
 }

 /* Exits on error */
 static int get_address(char *dev, int *htype)
 {
 	struct ifreq ifr;
 	struct sockaddr_ll me;
 	socklen_t alen;
 	int s;

 	s = xsocket(PF_PACKET, SOCK_DGRAM, 0);

 	memset(&ifr, 0, sizeof(ifr));
 	strncpy_IFNAMSIZ(ifr.ifr_name, dev);
 	xioctl(s, SIOCGIFINDEX, &ifr);

 	memset(&me, 0, sizeof(me));
 	me.sll_family = AF_PACKET;
 	me.sll_ifindex = ifr.ifr_ifindex;
 	me.sll_protocol = htons(ETH_P_LOOP);
 	xbind(s, (struct sockaddr*)&me, sizeof(me));
 	alen = sizeof(me);
 	getsockname(s, (struct sockaddr*)&me, &alen);
 	//never happens:
 	//if (getsockname(s, (struct sockaddr*)&me, &alen) == -1)
 	//	bb_perror_msg_and_die("getsockname");
 	close(s);
 	*htype = me.sll_hatype;
 	return me.sll_halen;
 }

 /* Exits on error */
 static void parse_address(char *dev, int hatype, int halen, char *lla, struct ifreq *ifr)
 {
 	int alen;

 	memset(ifr, 0, sizeof(*ifr));
 	strncpy_IFNAMSIZ(ifr->ifr_name, dev);
 	ifr->ifr_hwaddr.sa_family = hatype;

 	alen = hatype == 1/*ARPHRD_ETHER*/ ? 14/*ETH_HLEN*/ : 19/*INFINIBAND_HLEN*/;
 	alen = ll_addr_a2n((unsigned char *)(ifr->ifr_hwaddr.sa_data), alen, lla);
 	if (alen < 0)
 		exit(EXIT_FAILURE);
 	if (alen != halen) {
 		bb_error_msg_and_die("wrong address (%s) length: expected %d bytes", lla, halen);
 	}
 }

 /* Exits on error */
 static void set_address(struct ifreq *ifr, int brd)
 {
 	int s;

 	s = get_ctl_fd();
 	if (brd)
 		xioctl(s, SIOCSIFHWBROADCAST, ifr);
 	else
 		xioctl(s, SIOCSIFHWADDR, ifr);
 	close(s);
 }


 static void die_must_be_on_off(const char *msg) NORETURN;
 static void die_must_be_on_off(const char *msg)
 {
 	bb_error_msg_and_die("argument of \"%s\" must be \"on\" or \"off\"", msg);
 }

 /* Return value becomes exitcode. It's okay to not return at all */
 static int do_set(char **argv)
 {
 	char *dev = NULL;
 	uint32_t mask = 0;
 	uint32_t flags = 0;
 	int qlen = -1;
 	int mtu = -1;
 	char *newaddr = NULL;
 	char *newbrd = NULL;
 	struct ifreq ifr0, ifr1;
 	char *newname = NULL;
 	int htype, halen;
 	static const char keywords[] ALIGN1 =
 		"up\0""down\0""name\0""mtu\0""qlen\0""multicast\0"
 		"arp\0""address\0""dev\0";
 	enum { ARG_up = 0, ARG_down, ARG_name, ARG_mtu, ARG_qlen, ARG_multicast,
 		ARG_arp, ARG_addr, ARG_dev };
 	static const char str_on_off[] ALIGN1 = "on\0""off\0";
 	enum { PARM_on = 0, PARM_off };
 	smalluint key;

 	while (*argv) {
 		/* substring search ensures that e.g. "addr" and "address"
 		 * are both accepted */
 		key = index_in_substrings(keywords, *argv);
 		if (key == ARG_up) {
 			mask |= IFF_UP;
 			flags |= IFF_UP;
 		} else if (key == ARG_down) {
 			mask |= IFF_UP;
 			flags &= ~IFF_UP;
 		} else if (key == ARG_name) {
 			NEXT_ARG();
 			newname = *argv;
 		} else if (key == ARG_mtu) {
 			NEXT_ARG();
 			if (mtu != -1)
 				duparg("mtu", *argv);
 			mtu = get_unsigned(*argv, "mtu");
 		} else if (key == ARG_qlen) {
 			NEXT_ARG();
 			if (qlen != -1)
 				duparg("qlen", *argv);
 			qlen = get_unsigned(*argv, "qlen");
 		} else if (key == ARG_addr) {
 			NEXT_ARG();
 			newaddr = *argv;
 		} else if (key >= ARG_dev) {
 			if (key == ARG_dev) {
 				NEXT_ARG();
 			}
 			if (dev)
 				duparg2("dev", *argv);
 			dev = *argv;
 		} else {
 			int param;
 			NEXT_ARG();
 			param = index_in_strings(str_on_off, *argv);
 			if (key == ARG_multicast) {
 				if (param < 0)
 					die_must_be_on_off("multicast");
 				mask |= IFF_MULTICAST;
 				if (param == PARM_on)
 					flags |= IFF_MULTICAST;
 				else
 					flags &= ~IFF_MULTICAST;
 			} else if (key == ARG_arp) {
 				if (param < 0)
 					die_must_be_on_off("arp");
 				mask |= IFF_NOARP;
 				if (param == PARM_on)
 					flags &= ~IFF_NOARP;
 				else
 					flags |= IFF_NOARP;
 			}
 		}
 		argv++;
 	}

 	if (!dev) {
 		bb_error_msg_and_die(bb_msg_requires_arg, "\"dev\"");
 	}

 	if (newaddr || newbrd) {
 		halen = get_address(dev, &htype);
 		if (newaddr) {
 			parse_address(dev, htype, halen, newaddr, &ifr0);
 			set_address(&ifr0, 0);
 		}
 		if (newbrd) {
 			parse_address(dev, htype, halen, newbrd, &ifr1);
 			set_address(&ifr1, 1);
 		}
 	}

 	if (newname && strcmp(dev, newname)) {
 		do_changename(dev, newname);
 		dev = newname;
 	}
 	if (qlen != -1) {
 		set_qlen(dev, qlen);
 	}
 	if (mtu != -1) {
 		set_mtu(dev, mtu);
 	}
 	if (mask)
 		do_chflags(dev, flags, mask);
 	return 0;
 }

 static int ipaddr_list_link(char **argv)
 {
 	preferred_family = AF_PACKET;
 	return ipaddr_list_or_flush(argv, 0);
 }

 #ifndef NLMSG_TAIL
 #define NLMSG_TAIL(nmsg) \
 	((struct rtattr *) (((void *) (nmsg)) + NLMSG_ALIGN((nmsg)->nlmsg_len)))
 #endif
 /* Return value becomes exitcode. It's okay to not return at all */
 static int do_change(char **argv, const unsigned rtm)
 {
 	static const char keywords[] ALIGN1 =
 		"link\0""name\0""type\0""dev\0";
 	enum {
 		ARG_link,
 		ARG_name,
 		ARG_type,
 		ARG_dev,
 	};
 	struct rtnl_handle rth;
 	struct {
 		struct nlmsghdr  n;
 		struct ifinfomsg i;
 		char             buf[1024];
 	} req;
 	smalluint arg;
 	char *name_str = NULL, *link_str = NULL, *type_str = NULL, *dev_str = NULL;

 	memset(&req, 0, sizeof(req));

 	req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
 	req.n.nlmsg_flags = NLM_F_REQUEST;
 	req.n.nlmsg_type = rtm;
 	req.i.ifi_family = preferred_family;
 	if (rtm == RTM_NEWLINK)
 		req.n.nlmsg_flags |= NLM_F_CREATE|NLM_F_EXCL;

 	while (*argv) {
 		arg = index_in_substrings(keywords, *argv);
 		if (arg == ARG_link) {
 			NEXT_ARG();
 			link_str = *argv;
 		} else if (arg == ARG_name) {
 			NEXT_ARG();
 			name_str = *argv;
 		} else if (arg == ARG_type) {
 			NEXT_ARG();
 			type_str = *argv;
 		} else {
 			if (arg == ARG_dev) {
 				if (dev_str)
 					duparg(*argv, "dev");
 				NEXT_ARG();
 			}
 			dev_str = *argv;
 		}
 		argv++;
 	}
 	xrtnl_open(&rth);
 	ll_init_map(&rth);
 	if (type_str) {
 		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_str,
 				strlen(type_str));
 		linkinfo->rta_len = (void *)NLMSG_TAIL(&req.n) - (void *)linkinfo;
 	}
 	if (rtm != RTM_NEWLINK) {
 		if (!dev_str)
 			return 1; /* Need a device to delete */
 		req.i.ifi_index = xll_name_to_index(dev_str);
 	} else {
 		if (!name_str)
 			name_str = dev_str;
 		if (link_str) {
 			int idx = xll_name_to_index(link_str);
 			addattr_l(&req.n, sizeof(req), IFLA_LINK, &idx, 4);
 		}
 	}
 	if (name_str) {
 		const size_t name_len = strlen(name_str) + 1;
 		if (name_len < 2 || name_len > IFNAMSIZ)
 			invarg(name_str, "name");
 		addattr_l(&req.n, sizeof(req), IFLA_IFNAME, name_str, name_len);
 	}
 	if (rtnl_talk(&rth, &req.n, 0, 0, NULL, NULL, NULL) < 0)
 		return 2;
 	return 0;
 }

 /* Return value becomes exitcode. It's okay to not return at all */
 int FAST_FUNC do_iplink(char **argv)
 {
 	static const char keywords[] ALIGN1 =
 		"add\0""delete\0""set\0""show\0""lst\0""list\0";
 	if (*argv) {
 		smalluint key = index_in_substrings(keywords, *argv);
 		if (key > 5) /* invalid argument */
 			bb_error_msg_and_die(bb_msg_invalid_arg, *argv, applet_name);
 		argv++;
 		if (key <= 1) /* add/delete */
 			return do_change(argv, key ? RTM_DELLINK : RTM_NEWLINK);
 		else if (key == 2) /* set */
 			return do_set(argv);
 	}
 	/* show, lst, list */
 	return ipaddr_list_link(argv);
 }
	/* vi: set sw=4 ts=4: */
	/*
	* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
	*
	* Licensed under GPLv2 or later, see file LICENSE in this source tree.
	*/
	#include <net/if.h>
	#include <net/if_packet.h>
	#include <netpacket/packet.h>
	#include <net/ethernet.h>

	#include "ip_common.h" /* #include "libbb.h" is inside */
	#include "rt_names.h"
	#include "utils.h"

	#ifndef IFLA_LINKINFO
	# define IFLA_LINKINFO 18
	# define IFLA_INFO_KIND 1
	#endif

	/* taken from linux/sockios.h */
	#define SIOCSIFNAME 0x8923 /* set interface name */

	/* Exits on error */
	static int get_ctl_fd(void)
	{
	int fd;

	fd = socket(PF_INET, SOCK_DGRAM, 0);
	if (fd >= 0)
	return fd;
	fd = socket(PF_PACKET, SOCK_DGRAM, 0);
	if (fd >= 0)
	return fd;
	return xsocket(PF_INET6, SOCK_DGRAM, 0);
	}

	/* Exits on error */
	static void do_chflags(char *dev, uint32_t flags, uint32_t mask)
	{
	struct ifreq ifr;
	int fd;

	strncpy_IFNAMSIZ(ifr.ifr_name, dev);
	fd = get_ctl_fd();
	xioctl(fd, SIOCGIFFLAGS, &ifr);
	if ((ifr.ifr_flags ^ flags) & mask) {
	ifr.ifr_flags &= ~mask;
	ifr.ifr_flags \|= mask & flags;
	xioctl(fd, SIOCSIFFLAGS, &ifr);
	}
	close(fd);
	}

	/* Exits on error */
	static void do_changename(char dev, char newdev)
	{
	struct ifreq ifr;
	int fd;

	strncpy_IFNAMSIZ(ifr.ifr_name, dev);
	strncpy_IFNAMSIZ(ifr.ifr_newname, newdev);
	fd = get_ctl_fd();
	xioctl(fd, SIOCSIFNAME, &ifr);
	close(fd);
	}

	/* Exits on error */
	static void set_qlen(char *dev, int qlen)
	{
	struct ifreq ifr;
	int s;

	s = get_ctl_fd();
	memset(&ifr, 0, sizeof(ifr));
	strncpy_IFNAMSIZ(ifr.ifr_name, dev);
	ifr.ifr_qlen = qlen;
	xioctl(s, SIOCSIFTXQLEN, &ifr);
	close(s);
	}

	/* Exits on error */
	static void set_mtu(char *dev, int mtu)
	{
	struct ifreq ifr;
	int s;

	s = get_ctl_fd();
	memset(&ifr, 0, sizeof(ifr));
	strncpy_IFNAMSIZ(ifr.ifr_name, dev);
	ifr.ifr_mtu = mtu;
	xioctl(s, SIOCSIFMTU, &ifr);
	close(s);
	}

	/* Exits on error */
	static int get_address(char dev, int htype)
	{
	struct ifreq ifr;
	struct sockaddr_ll me;
	socklen_t alen;
	int s;

	s = xsocket(PF_PACKET, SOCK_DGRAM, 0);

	memset(&ifr, 0, sizeof(ifr));
	strncpy_IFNAMSIZ(ifr.ifr_name, dev);
	xioctl(s, SIOCGIFINDEX, &ifr);

	memset(&me, 0, sizeof(me));
	me.sll_family = AF_PACKET;
	me.sll_ifindex = ifr.ifr_ifindex;
	me.sll_protocol = htons(ETH_P_LOOP);
	xbind(s, (struct sockaddr*)&me, sizeof(me));
	alen = sizeof(me);
	getsockname(s, (struct sockaddr*)&me, &alen);
	//never happens:
	//if (getsockname(s, (struct sockaddr*)&me, &alen) == -1)
	// bb_perror_msg_and_die("getsockname");
	close(s);
	*htype = me.sll_hatype;
	return me.sll_halen;
	}

	/* Exits on error */
	static void parse_address(char dev, int hatype, int halen, char lla, struct ifreq *ifr)
	{
	int alen;

	memset(ifr, 0, sizeof(*ifr));
	strncpy_IFNAMSIZ(ifr->ifr_name, dev);
	ifr->ifr_hwaddr.sa_family = hatype;

	alen = hatype == 1/ARPHRD_ETHER/ ? 14/ETH_HLEN/ : 19/INFINIBAND_HLEN/;
	alen = ll_addr_a2n((unsigned char *)(ifr->ifr_hwaddr.sa_data), alen, lla);
	if (alen < 0)
	exit(EXIT_FAILURE);
	if (alen != halen) {
	bb_error_msg_and_die("wrong address (%s) length: expected %d bytes", lla, halen);
	}
	}

	/* Exits on error */
	static void set_address(struct ifreq *ifr, int brd)
	{
	int s;

	s = get_ctl_fd();
	if (brd)
	xioctl(s, SIOCSIFHWBROADCAST, ifr);
	else
	xioctl(s, SIOCSIFHWADDR, ifr);
	close(s);
	}


	static void die_must_be_on_off(const char *msg) NORETURN;
	static void die_must_be_on_off(const char *msg)
	{
	bb_error_msg_and_die("argument of \"%s\" must be \"on\" or \"off\"", msg);
	}

	/* Return value becomes exitcode. It's okay to not return at all */
	static int do_set(char **argv)
	{
	char *dev = NULL;
	uint32_t mask = 0;
	uint32_t flags = 0;
	int qlen = -1;
	int mtu = -1;
	char *newaddr = NULL;
	char *newbrd = NULL;
	struct ifreq ifr0, ifr1;
	char *newname = NULL;
	int htype, halen;
	static const char keywords[] ALIGN1 =
	"up\0""down\0""name\0""mtu\0""qlen\0""multicast\0"
	"arp\0""address\0""dev\0";
	enum { ARG_up = 0, ARG_down, ARG_name, ARG_mtu, ARG_qlen, ARG_multicast,
	ARG_arp, ARG_addr, ARG_dev };
	static const char str_on_off[] ALIGN1 = "on\0""off\0";
	enum { PARM_on = 0, PARM_off };
	smalluint key;

	while (*argv) {
	/* substring search ensures that e.g. "addr" and "address"
	* are both accepted */
	key = index_in_substrings(keywords, *argv);
	if (key == ARG_up) {
	mask \|= IFF_UP;
	flags \|= IFF_UP;
	} else if (key == ARG_down) {
	mask \|= IFF_UP;
	flags &= ~IFF_UP;
	} else if (key == ARG_name) {
	NEXT_ARG();
	newname = *argv;
	} else if (key == ARG_mtu) {
	NEXT_ARG();
	if (mtu != -1)
	duparg("mtu", *argv);
	mtu = get_unsigned(*argv, "mtu");
	} else if (key == ARG_qlen) {
	NEXT_ARG();
	if (qlen != -1)
	duparg("qlen", *argv);
	qlen = get_unsigned(*argv, "qlen");
	} else if (key == ARG_addr) {
	NEXT_ARG();
	newaddr = *argv;
	} else if (key >= ARG_dev) {
	if (key == ARG_dev) {
	NEXT_ARG();
	}
	if (dev)
	duparg2("dev", *argv);
	dev = *argv;
	} else {
	int param;
	NEXT_ARG();
	param = index_in_strings(str_on_off, *argv);
	if (key == ARG_multicast) {
	if (param < 0)
	die_must_be_on_off("multicast");
	mask \|= IFF_MULTICAST;
	if (param == PARM_on)
	flags \|= IFF_MULTICAST;
	else
	flags &= ~IFF_MULTICAST;
	} else if (key == ARG_arp) {
	if (param < 0)
	die_must_be_on_off("arp");
	mask \|= IFF_NOARP;
	if (param == PARM_on)
	flags &= ~IFF_NOARP;
	else
	flags \|= IFF_NOARP;
	}
	}
	argv++;
	}

	if (!dev) {
	bb_error_msg_and_die(bb_msg_requires_arg, "\"dev\"");
	}

	if (newaddr \|\| newbrd) {
	halen = get_address(dev, &htype);
	if (newaddr) {
	parse_address(dev, htype, halen, newaddr, &ifr0);
	set_address(&ifr0, 0);
	}
	if (newbrd) {
	parse_address(dev, htype, halen, newbrd, &ifr1);
	set_address(&ifr1, 1);
	}
	}

	if (newname && strcmp(dev, newname)) {
	do_changename(dev, newname);
	dev = newname;
	}
	if (qlen != -1) {
	set_qlen(dev, qlen);
	}
	if (mtu != -1) {
	set_mtu(dev, mtu);
	}
	if (mask)
	do_chflags(dev, flags, mask);
	return 0;
	}

	static int ipaddr_list_link(char **argv)
	{
	preferred_family = AF_PACKET;
	return ipaddr_list_or_flush(argv, 0);
	}

	#ifndef NLMSG_TAIL
	#define NLMSG_TAIL(nmsg) \
	((struct rtattr ) (((void ) (nmsg)) + NLMSG_ALIGN((nmsg)->nlmsg_len)))
	#endif
	/* Return value becomes exitcode. It's okay to not return at all */
	static int do_change(char **argv, const unsigned rtm)
	{
	static const char keywords[] ALIGN1 =
	"link\0""name\0""type\0""dev\0";
	enum {
	ARG_link,
	ARG_name,
	ARG_type,
	ARG_dev,
	};
	struct rtnl_handle rth;
	struct {
	struct nlmsghdr n;
	struct ifinfomsg i;
	char buf[1024];
	} req;
	smalluint arg;
	char name_str = NULL, link_str = NULL, type_str = NULL, dev_str = NULL;

	memset(&req, 0, sizeof(req));

	req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
	req.n.nlmsg_flags = NLM_F_REQUEST;
	req.n.nlmsg_type = rtm;
	req.i.ifi_family = preferred_family;
	if (rtm == RTM_NEWLINK)
	req.n.nlmsg_flags \|= NLM_F_CREATE\|NLM_F_EXCL;

	while (*argv) {
	arg = index_in_substrings(keywords, *argv);
	if (arg == ARG_link) {
	NEXT_ARG();
	link_str = *argv;
	} else if (arg == ARG_name) {
	NEXT_ARG();
	name_str = *argv;
	} else if (arg == ARG_type) {
	NEXT_ARG();
	type_str = *argv;
	} else {
	if (arg == ARG_dev) {
	if (dev_str)
	duparg(*argv, "dev");
	NEXT_ARG();
	}
	dev_str = *argv;
	}
	argv++;
	}
	xrtnl_open(&rth);
	ll_init_map(&rth);
	if (type_str) {
	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_str,
	strlen(type_str));
	linkinfo->rta_len = (void )NLMSG_TAIL(&req.n) - (void )linkinfo;
	}
	if (rtm != RTM_NEWLINK) {
	if (!dev_str)
	return 1; /* Need a device to delete */
	req.i.ifi_index = xll_name_to_index(dev_str);
	} else {
	if (!name_str)
	name_str = dev_str;
	if (link_str) {
	int idx = xll_name_to_index(link_str);
	addattr_l(&req.n, sizeof(req), IFLA_LINK, &idx, 4);
	}
	}
	if (name_str) {
	const size_t name_len = strlen(name_str) + 1;
	if (name_len < 2 \|\| name_len > IFNAMSIZ)
	invarg(name_str, "name");
	addattr_l(&req.n, sizeof(req), IFLA_IFNAME, name_str, name_len);
	}
	if (rtnl_talk(&rth, &req.n, 0, 0, NULL, NULL, NULL) < 0)
	return 2;
	return 0;
	}

	/* Return value becomes exitcode. It's okay to not return at all */
	int FAST_FUNC do_iplink(char **argv)
	{
	static const char keywords[] ALIGN1 =
	"add\0""delete\0""set\0""show\0""lst\0""list\0";
	if (*argv) {
	smalluint key = index_in_substrings(keywords, *argv);
	if (key > 5) /* invalid argument */
	bb_error_msg_and_die(bb_msg_invalid_arg, *argv, applet_name);
	argv++;
	if (key <= 1) /* add/delete */
	return do_change(argv, key ? RTM_DELLINK : RTM_NEWLINK);
	else if (key == 2) /* set */
	return do_set(argv);
	}
	/* show, lst, list */
	return ipaddr_list_link(argv);
	}