ip/link_gre6.c - maze/iproute2 - Git at Google

 /*
  * link_gre6.c	gre driver module
  *
  *		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:	Dmitry Kozlov <xeb@mail.ru>
  *
  */

 #include <string.h>
 #include <net/if.h>
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <arpa/inet.h>

 #include <linux/ip.h>
 #include <linux/if_tunnel.h>
 #include <linux/ip6_tunnel.h>

 #include "rt_names.h"
 #include "utils.h"
 #include "ip_common.h"
 #include "tunnel.h"

 #define IP6_FLOWINFO_TCLASS	htonl(0x0FF00000)
 #define IP6_FLOWINFO_FLOWLABEL	htonl(0x000FFFFF)

 #define DEFAULT_TNL_HOP_LIMIT	(64)

 static void usage(void) __attribute__((noreturn));
 static void usage(void)
 {
 	fprintf(stderr, "Usage: ip link { add | set | change | replace | del } NAME\n");
 	fprintf(stderr, "          type { ip6gre | ip6gretap } [ remote ADDR ] [ local ADDR ]\n");
 	fprintf(stderr, "          [ [i|o]seq ] [ [i|o]key KEY ] [ [i|o]csum ]\n");
 	fprintf(stderr, "          [ hoplimit TTL ] [ encaplimit ELIM ]\n");
 	fprintf(stderr, "          [ tclass TCLASS ] [ flowlabel FLOWLABEL ]\n");
 	fprintf(stderr, "          [ dscp inherit ] [ dev PHYS_DEV ]\n");
 	fprintf(stderr, "\n");
 	fprintf(stderr, "Where: NAME      := STRING\n");
 	fprintf(stderr, "       ADDR      := IPV6_ADDRESS\n");
 	fprintf(stderr, "       TTL       := { 0..255 } (default=%d)\n",
 		DEFAULT_TNL_HOP_LIMIT);
 	fprintf(stderr, "       KEY       := { DOTTED_QUAD | NUMBER }\n");
 	fprintf(stderr, "       ELIM      := { none | 0..255 }(default=%d)\n",
 		IPV6_DEFAULT_TNL_ENCAP_LIMIT);
 	fprintf(stderr, "       TCLASS    := { 0x0..0xff | inherit }\n");
 	fprintf(stderr, "       FLOWLABEL := { 0x0..0xfffff | inherit }\n");
 	exit(-1);
 }

 static int gre_parse_opt(struct link_util *lu, int argc, char **argv,
 			 struct nlmsghdr *n)
 {
 	struct {
 		struct nlmsghdr n;
 		struct ifinfomsg i;
 		char buf[1024];
 	} req;
 	struct ifinfomsg *ifi = (struct ifinfomsg *)(n + 1);
 	struct rtattr *tb[IFLA_MAX + 1];
 	struct rtattr *linkinfo[IFLA_INFO_MAX+1];
 	struct rtattr *greinfo[IFLA_GRE_MAX + 1];
 	__u16 iflags = 0;
 	__u16 oflags = 0;
 	unsigned ikey = 0;
 	unsigned okey = 0;
 	struct in6_addr raddr = IN6ADDR_ANY_INIT;
 	struct in6_addr laddr = IN6ADDR_ANY_INIT;
 	unsigned link = 0;
 	unsigned flowinfo = 0;
 	unsigned flags = 0;
 	__u8 hop_limit = DEFAULT_TNL_HOP_LIMIT;
 	__u8 encap_limit = IPV6_DEFAULT_TNL_ENCAP_LIMIT;
 	int len;

 	if (!(n->nlmsg_flags & NLM_F_CREATE)) {
 		memset(&req, 0, sizeof(req));

 		req.n.nlmsg_len = NLMSG_LENGTH(sizeof(*ifi));
 		req.n.nlmsg_flags = NLM_F_REQUEST;
 		req.n.nlmsg_type = RTM_GETLINK;
 		req.i.ifi_family = preferred_family;
 		req.i.ifi_index = ifi->ifi_index;

 		if (rtnl_talk(&rth, &req.n, 0, 0, &req.n) < 0) {
 get_failed:
 			fprintf(stderr,
 				"Failed to get existing tunnel info.\n");
 			return -1;
 		}

 		len = req.n.nlmsg_len;
 		len -= NLMSG_LENGTH(sizeof(*ifi));
 		if (len < 0)
 			goto get_failed;

 		parse_rtattr(tb, IFLA_MAX, IFLA_RTA(&req.i), len);

 		if (!tb[IFLA_LINKINFO])
 			goto get_failed;

 		parse_rtattr_nested(linkinfo, IFLA_INFO_MAX, tb[IFLA_LINKINFO]);

 		if (!linkinfo[IFLA_INFO_DATA])
 			goto get_failed;

 		parse_rtattr_nested(greinfo, IFLA_GRE_MAX,
 				    linkinfo[IFLA_INFO_DATA]);

 		if (greinfo[IFLA_GRE_IKEY])
 			ikey = rta_getattr_u32(greinfo[IFLA_GRE_IKEY]);

 		if (greinfo[IFLA_GRE_OKEY])
 			okey = rta_getattr_u32(greinfo[IFLA_GRE_OKEY]);

 		if (greinfo[IFLA_GRE_IFLAGS])
 			iflags = rta_getattr_u16(greinfo[IFLA_GRE_IFLAGS]);

 		if (greinfo[IFLA_GRE_OFLAGS])
 			oflags = rta_getattr_u16(greinfo[IFLA_GRE_OFLAGS]);

 		if (greinfo[IFLA_GRE_LOCAL])
 			memcpy(&laddr, RTA_DATA(greinfo[IFLA_GRE_LOCAL]), sizeof(laddr));

 		if (greinfo[IFLA_GRE_REMOTE])
 			memcpy(&raddr, RTA_DATA(greinfo[IFLA_GRE_REMOTE]), sizeof(raddr));

 		if (greinfo[IFLA_GRE_TTL])
 			hop_limit = rta_getattr_u8(greinfo[IFLA_GRE_TTL]);

 		if (greinfo[IFLA_GRE_LINK])
 			link = rta_getattr_u32(greinfo[IFLA_GRE_LINK]);

 		if (greinfo[IFLA_GRE_ENCAP_LIMIT])
 			encap_limit = rta_getattr_u8(greinfo[IFLA_GRE_ENCAP_LIMIT]);

 		if (greinfo[IFLA_GRE_FLOWINFO])
 			flowinfo = rta_getattr_u32(greinfo[IFLA_GRE_FLOWINFO]);

 		if (greinfo[IFLA_GRE_FLAGS])
 			flags = rta_getattr_u32(greinfo[IFLA_GRE_FLAGS]);
 	}

 	while (argc > 0) {
 		if (!matches(*argv, "key")) {
 			unsigned uval;

 			NEXT_ARG();
 			iflags |= GRE_KEY;
 			oflags |= GRE_KEY;
 			if (strchr(*argv, '.'))
 				uval = get_addr32(*argv);
 			else {
 				if (get_unsigned(&uval, *argv, 0) < 0) {
 					fprintf(stderr,
 						"Invalid value for \"key\"\n");
 					exit(-1);
 				}
 				uval = htonl(uval);
 			}

 			ikey = okey = uval;
 		} else if (!matches(*argv, "ikey")) {
 			unsigned uval;

 			NEXT_ARG();
 			iflags |= GRE_KEY;
 			if (strchr(*argv, '.'))
 				uval = get_addr32(*argv);
 			else {
 				if (get_unsigned(&uval, *argv, 0)<0) {
 					fprintf(stderr, "invalid value of \"ikey\"\n");
 					exit(-1);
 				}
 				uval = htonl(uval);
 			}
 			ikey = uval;
 		} else if (!matches(*argv, "okey")) {
 			unsigned uval;

 			NEXT_ARG();
 			oflags |= GRE_KEY;
 			if (strchr(*argv, '.'))
 				uval = get_addr32(*argv);
 			else {
 				if (get_unsigned(&uval, *argv, 0)<0) {
 					fprintf(stderr, "invalid value of \"okey\"\n");
 					exit(-1);
 				}
 				uval = htonl(uval);
 			}
 			okey = uval;
 		} else if (!matches(*argv, "seq")) {
 			iflags |= GRE_SEQ;
 			oflags |= GRE_SEQ;
 		} else if (!matches(*argv, "iseq")) {
 			iflags |= GRE_SEQ;
 		} else if (!matches(*argv, "oseq")) {
 			oflags |= GRE_SEQ;
 		} else if (!matches(*argv, "csum")) {
 			iflags |= GRE_CSUM;
 			oflags |= GRE_CSUM;
 		} else if (!matches(*argv, "icsum")) {
 			iflags |= GRE_CSUM;
 		} else if (!matches(*argv, "ocsum")) {
 			oflags |= GRE_CSUM;
 		} else if (!matches(*argv, "remote")) {
 			inet_prefix addr;
 			NEXT_ARG();
 			get_prefix(&addr, *argv, preferred_family);
 			if (addr.family == AF_UNSPEC)
 				invarg("\"remote\" address family is AF_UNSPEC", *argv);
 			memcpy(&raddr, &addr.data, sizeof(raddr));
 		} else if (!matches(*argv, "local")) {
 			inet_prefix addr;
 			NEXT_ARG();
 			get_prefix(&addr, *argv, preferred_family);
 			if (addr.family == AF_UNSPEC)
 				invarg("\"local\" address family is AF_UNSPEC", *argv);
 			memcpy(&laddr, &addr.data, sizeof(laddr));
 		} else if (!matches(*argv, "dev")) {
 			NEXT_ARG();
 			link = if_nametoindex(*argv);
 			if (link == 0)
 				exit(-1);
 		} else if (!matches(*argv, "ttl") ||
 			   !matches(*argv, "hoplimit")) {
 			__u8 uval;
 			NEXT_ARG();
 			if (get_u8(&uval, *argv, 0))
 				invarg("invalid TTL", *argv);
 			hop_limit = uval;
 		} else if (!matches(*argv, "tos") ||
 			   !matches(*argv, "tclass") ||
 			   !matches(*argv, "dsfield")) {
 			__u8 uval;
 			NEXT_ARG();
 			if (strcmp(*argv, "inherit") == 0)
 				flags |= IP6_TNL_F_USE_ORIG_TCLASS;
 			else {
 				if (get_u8(&uval, *argv, 16))
 					invarg("invalid TClass", *argv);
 				flowinfo |= htonl((__u32)uval << 20) & IP6_FLOWINFO_TCLASS;
 				flags &= ~IP6_TNL_F_USE_ORIG_TCLASS;
 			}
 		} else if (strcmp(*argv, "flowlabel") == 0 ||
 			   strcmp(*argv, "fl") == 0) {
 			__u32 uval;
 			NEXT_ARG();
 			if (strcmp(*argv, "inherit") == 0)
 				flags |= IP6_TNL_F_USE_ORIG_FLOWLABEL;
 			else {
 				if (get_u32(&uval, *argv, 16))
 					invarg("invalid Flowlabel", *argv);
 				if (uval > 0xFFFFF)
 					invarg("invalid Flowlabel", *argv);
 				flowinfo |= htonl(uval) & IP6_FLOWINFO_FLOWLABEL;
 				flags &= ~IP6_TNL_F_USE_ORIG_FLOWLABEL;
 			}
 		} else if (strcmp(*argv, "dscp") == 0) {
 			NEXT_ARG();
 			if (strcmp(*argv, "inherit") != 0)
 				invarg("not inherit", *argv);
 			flags |= IP6_TNL_F_RCV_DSCP_COPY;
 		} else
 			usage();
 		argc--; argv++;
 	}

 	addattr32(n, 1024, IFLA_GRE_IKEY, ikey);
 	addattr32(n, 1024, IFLA_GRE_OKEY, okey);
 	addattr_l(n, 1024, IFLA_GRE_IFLAGS, &iflags, 2);
 	addattr_l(n, 1024, IFLA_GRE_OFLAGS, &oflags, 2);
 	addattr_l(n, 1024, IFLA_GRE_LOCAL, &laddr, sizeof(laddr));
 	addattr_l(n, 1024, IFLA_GRE_REMOTE, &raddr, sizeof(raddr));
 	if (link)
 		addattr32(n, 1024, IFLA_GRE_LINK, link);
 	addattr_l(n, 1024, IFLA_GRE_TTL, &hop_limit, 1);
 	addattr_l(n, 1024, IFLA_GRE_ENCAP_LIMIT, &encap_limit, 1);
 	addattr_l(n, 1024, IFLA_GRE_FLOWINFO, &flowinfo, 4);
 	addattr_l(n, 1024, IFLA_GRE_FLAGS, &flowinfo, 4);

 	return 0;
 }

 static void gre_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
 {
 	char s1[1024];
 	char s2[64];
 	const char *local = "any";
 	const char *remote = "any";
 	unsigned iflags = 0;
 	unsigned oflags = 0;
 	unsigned flags = 0;
 	unsigned flowinfo = 0;
 	struct in6_addr in6_addr_any = IN6ADDR_ANY_INIT;

 	if (!tb)
 		return;

 	if (tb[IFLA_GRE_FLAGS])
 		flags = rta_getattr_u32(tb[IFLA_GRE_FLAGS]);

 	if (tb[IFLA_GRE_FLOWINFO])
 		flags = rta_getattr_u32(tb[IFLA_GRE_FLOWINFO]);

 	if (tb[IFLA_GRE_REMOTE]) {
 		struct in6_addr addr;
 		memcpy(&addr, RTA_DATA(tb[IFLA_GRE_REMOTE]), sizeof(addr));

 		if (memcmp(&addr, &in6_addr_any, sizeof(addr)))
 			remote = format_host(AF_INET6, sizeof(addr), &addr, s1, sizeof(s1));
 	}

 	fprintf(f, "remote %s ", remote);

 	if (tb[IFLA_GRE_LOCAL]) {
 		struct in6_addr addr;
 		memcpy(&addr, RTA_DATA(tb[IFLA_GRE_LOCAL]), sizeof(addr));

 		if (memcmp(&addr, &in6_addr_any, sizeof(addr)))
 			local = format_host(AF_INET6, sizeof(addr), &addr, s1, sizeof(s1));
 	}

 	fprintf(f, "local %s ", local);

 	if (tb[IFLA_GRE_LINK] && rta_getattr_u32(tb[IFLA_GRE_LINK])) {
 		unsigned link = rta_getattr_u32(tb[IFLA_GRE_LINK]);
 		const char *n = if_indextoname(link, s2);

 		if (n)
 			fprintf(f, "dev %s ", n);
 		else
 			fprintf(f, "dev %u ", link);
 	}

 	if (tb[IFLA_GRE_TTL] && rta_getattr_u8(tb[IFLA_GRE_TTL]))
 		fprintf(f, "hoplimit %d ", rta_getattr_u8(tb[IFLA_GRE_TTL]));

 	if (flags & IP6_TNL_F_IGN_ENCAP_LIMIT)
 		fprintf(f, "encaplimit none ");
 	else if (tb[IFLA_GRE_ENCAP_LIMIT]) {
 		int encap_limit = rta_getattr_u8(tb[IFLA_GRE_ENCAP_LIMIT]);

 		fprintf(f, "encaplimit %d ", encap_limit);
 	}

 	if (flags & IP6_TNL_F_USE_ORIG_FLOWLABEL)
 		fprintf(f, "flowlabel inherit ");
 	else
 		fprintf(f, "flowlabel 0x%05x ", ntohl(flowinfo & IP6_FLOWINFO_FLOWLABEL));

 	if (flags & IP6_TNL_F_RCV_DSCP_COPY)
 		fprintf(f, "dscp inherit ");

 	if (tb[IFLA_GRE_IFLAGS])
 		iflags = rta_getattr_u16(tb[IFLA_GRE_IFLAGS]);

 	if (tb[IFLA_GRE_OFLAGS])
 		oflags = rta_getattr_u16(tb[IFLA_GRE_OFLAGS]);

 	if ((iflags & GRE_KEY) && tb[IFLA_GRE_IKEY]) {
 		inet_ntop(AF_INET, RTA_DATA(tb[IFLA_GRE_IKEY]), s2, sizeof(s2));
 		fprintf(f, "ikey %s ", s2);
 	}

 	if ((oflags & GRE_KEY) && tb[IFLA_GRE_OKEY]) {
 		inet_ntop(AF_INET, RTA_DATA(tb[IFLA_GRE_OKEY]), s2, sizeof(s2));
 		fprintf(f, "okey %s ", s2);
 	}

 	if (iflags & GRE_SEQ)
 		fputs("iseq ", f);
 	if (oflags & GRE_SEQ)
 		fputs("oseq ", f);
 	if (iflags & GRE_CSUM)
 		fputs("icsum ", f);
 	if (oflags & GRE_CSUM)
 		fputs("ocsum ", f);
 }

 struct link_util ip6gre_link_util = {
 	.id = "ip6gre",
 	.maxattr = IFLA_GRE_MAX,
 	.parse_opt = gre_parse_opt,
 	.print_opt = gre_print_opt,
 };

 struct link_util ip6gretap_link_util = {
 	.id = "ip6gretap",
 	.maxattr = IFLA_GRE_MAX,
 	.parse_opt = gre_parse_opt,
 	.print_opt = gre_print_opt,
 };
	/*
	* link_gre6.c gre driver module
	*
	* 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: Dmitry Kozlov <xeb@mail.ru>
	*
	*/

	#include <string.h>
	#include <net/if.h>
	#include <sys/types.h>
	#include <sys/socket.h>
	#include <arpa/inet.h>

	#include <linux/ip.h>
	#include <linux/if_tunnel.h>
	#include <linux/ip6_tunnel.h>

	#include "rt_names.h"
	#include "utils.h"
	#include "ip_common.h"
	#include "tunnel.h"

	#define IP6_FLOWINFO_TCLASS htonl(0x0FF00000)
	#define IP6_FLOWINFO_FLOWLABEL htonl(0x000FFFFF)

	#define DEFAULT_TNL_HOP_LIMIT (64)

	static void usage(void) __attribute__((noreturn));
	static void usage(void)
	{
	fprintf(stderr, "Usage: ip link { add \| set \| change \| replace \| del } NAME\n");
	fprintf(stderr, " type { ip6gre \| ip6gretap } [ remote ADDR ] [ local ADDR ]\n");
	fprintf(stderr, " [ [i\|o]seq ] [ [i\|o]key KEY ] [ [i\|o]csum ]\n");
	fprintf(stderr, " [ hoplimit TTL ] [ encaplimit ELIM ]\n");
	fprintf(stderr, " [ tclass TCLASS ] [ flowlabel FLOWLABEL ]\n");
	fprintf(stderr, " [ dscp inherit ] [ dev PHYS_DEV ]\n");
	fprintf(stderr, "\n");
	fprintf(stderr, "Where: NAME := STRING\n");
	fprintf(stderr, " ADDR := IPV6_ADDRESS\n");
	fprintf(stderr, " TTL := { 0..255 } (default=%d)\n",
	DEFAULT_TNL_HOP_LIMIT);
	fprintf(stderr, " KEY := { DOTTED_QUAD \| NUMBER }\n");
	fprintf(stderr, " ELIM := { none \| 0..255 }(default=%d)\n",
	IPV6_DEFAULT_TNL_ENCAP_LIMIT);
	fprintf(stderr, " TCLASS := { 0x0..0xff \| inherit }\n");
	fprintf(stderr, " FLOWLABEL := { 0x0..0xfffff \| inherit }\n");
	exit(-1);
	}

	static int gre_parse_opt(struct link_util lu, int argc, char *argv,
	struct nlmsghdr *n)
	{
	struct {
	struct nlmsghdr n;
	struct ifinfomsg i;
	char buf[1024];
	} req;
	struct ifinfomsg ifi = (struct ifinfomsg )(n + 1);
	struct rtattr *tb[IFLA_MAX + 1];
	struct rtattr *linkinfo[IFLA_INFO_MAX+1];
	struct rtattr *greinfo[IFLA_GRE_MAX + 1];
	__u16 iflags = 0;
	__u16 oflags = 0;
	unsigned ikey = 0;
	unsigned okey = 0;
	struct in6_addr raddr = IN6ADDR_ANY_INIT;
	struct in6_addr laddr = IN6ADDR_ANY_INIT;
	unsigned link = 0;
	unsigned flowinfo = 0;
	unsigned flags = 0;
	__u8 hop_limit = DEFAULT_TNL_HOP_LIMIT;
	__u8 encap_limit = IPV6_DEFAULT_TNL_ENCAP_LIMIT;
	int len;

	if (!(n->nlmsg_flags & NLM_F_CREATE)) {
	memset(&req, 0, sizeof(req));

	req.n.nlmsg_len = NLMSG_LENGTH(sizeof(*ifi));
	req.n.nlmsg_flags = NLM_F_REQUEST;
	req.n.nlmsg_type = RTM_GETLINK;
	req.i.ifi_family = preferred_family;
	req.i.ifi_index = ifi->ifi_index;

	if (rtnl_talk(&rth, &req.n, 0, 0, &req.n) < 0) {
	get_failed:
	fprintf(stderr,
	"Failed to get existing tunnel info.\n");
	return -1;
	}

	len = req.n.nlmsg_len;
	len -= NLMSG_LENGTH(sizeof(*ifi));
	if (len < 0)
	goto get_failed;

	parse_rtattr(tb, IFLA_MAX, IFLA_RTA(&req.i), len);

	if (!tb[IFLA_LINKINFO])
	goto get_failed;

	parse_rtattr_nested(linkinfo, IFLA_INFO_MAX, tb[IFLA_LINKINFO]);

	if (!linkinfo[IFLA_INFO_DATA])
	goto get_failed;

	parse_rtattr_nested(greinfo, IFLA_GRE_MAX,
	linkinfo[IFLA_INFO_DATA]);

	if (greinfo[IFLA_GRE_IKEY])
	ikey = rta_getattr_u32(greinfo[IFLA_GRE_IKEY]);

	if (greinfo[IFLA_GRE_OKEY])
	okey = rta_getattr_u32(greinfo[IFLA_GRE_OKEY]);

	if (greinfo[IFLA_GRE_IFLAGS])
	iflags = rta_getattr_u16(greinfo[IFLA_GRE_IFLAGS]);

	if (greinfo[IFLA_GRE_OFLAGS])
	oflags = rta_getattr_u16(greinfo[IFLA_GRE_OFLAGS]);

	if (greinfo[IFLA_GRE_LOCAL])
	memcpy(&laddr, RTA_DATA(greinfo[IFLA_GRE_LOCAL]), sizeof(laddr));

	if (greinfo[IFLA_GRE_REMOTE])
	memcpy(&raddr, RTA_DATA(greinfo[IFLA_GRE_REMOTE]), sizeof(raddr));

	if (greinfo[IFLA_GRE_TTL])
	hop_limit = rta_getattr_u8(greinfo[IFLA_GRE_TTL]);

	if (greinfo[IFLA_GRE_LINK])
	link = rta_getattr_u32(greinfo[IFLA_GRE_LINK]);

	if (greinfo[IFLA_GRE_ENCAP_LIMIT])
	encap_limit = rta_getattr_u8(greinfo[IFLA_GRE_ENCAP_LIMIT]);

	if (greinfo[IFLA_GRE_FLOWINFO])
	flowinfo = rta_getattr_u32(greinfo[IFLA_GRE_FLOWINFO]);

	if (greinfo[IFLA_GRE_FLAGS])
	flags = rta_getattr_u32(greinfo[IFLA_GRE_FLAGS]);
	}

	while (argc > 0) {
	if (!matches(*argv, "key")) {
	unsigned uval;

	NEXT_ARG();
	iflags \|= GRE_KEY;
	oflags \|= GRE_KEY;
	if (strchr(*argv, '.'))
	uval = get_addr32(*argv);
	else {
	if (get_unsigned(&uval, *argv, 0) < 0) {
	fprintf(stderr,
	"Invalid value for \"key\"\n");
	exit(-1);
	}
	uval = htonl(uval);
	}

	ikey = okey = uval;
	} else if (!matches(*argv, "ikey")) {
	unsigned uval;

	NEXT_ARG();
	iflags \|= GRE_KEY;
	if (strchr(*argv, '.'))
	uval = get_addr32(*argv);
	else {
	if (get_unsigned(&uval, *argv, 0)<0) {
	fprintf(stderr, "invalid value of \"ikey\"\n");
	exit(-1);
	}
	uval = htonl(uval);
	}
	ikey = uval;
	} else if (!matches(*argv, "okey")) {
	unsigned uval;

	NEXT_ARG();
	oflags \|= GRE_KEY;
	if (strchr(*argv, '.'))
	uval = get_addr32(*argv);
	else {
	if (get_unsigned(&uval, *argv, 0)<0) {
	fprintf(stderr, "invalid value of \"okey\"\n");
	exit(-1);
	}
	uval = htonl(uval);
	}
	okey = uval;
	} else if (!matches(*argv, "seq")) {
	iflags \|= GRE_SEQ;
	oflags \|= GRE_SEQ;
	} else if (!matches(*argv, "iseq")) {
	iflags \|= GRE_SEQ;
	} else if (!matches(*argv, "oseq")) {
	oflags \|= GRE_SEQ;
	} else if (!matches(*argv, "csum")) {
	iflags \|= GRE_CSUM;
	oflags \|= GRE_CSUM;
	} else if (!matches(*argv, "icsum")) {
	iflags \|= GRE_CSUM;
	} else if (!matches(*argv, "ocsum")) {
	oflags \|= GRE_CSUM;
	} else if (!matches(*argv, "remote")) {
	inet_prefix addr;
	NEXT_ARG();
	get_prefix(&addr, *argv, preferred_family);
	if (addr.family == AF_UNSPEC)
	invarg("\"remote\" address family is AF_UNSPEC", *argv);
	memcpy(&raddr, &addr.data, sizeof(raddr));
	} else if (!matches(*argv, "local")) {
	inet_prefix addr;
	NEXT_ARG();
	get_prefix(&addr, *argv, preferred_family);
	if (addr.family == AF_UNSPEC)
	invarg("\"local\" address family is AF_UNSPEC", *argv);
	memcpy(&laddr, &addr.data, sizeof(laddr));
	} else if (!matches(*argv, "dev")) {
	NEXT_ARG();
	link = if_nametoindex(*argv);
	if (link == 0)
	exit(-1);
	} else if (!matches(*argv, "ttl") \|\|
	!matches(*argv, "hoplimit")) {
	__u8 uval;
	NEXT_ARG();
	if (get_u8(&uval, *argv, 0))
	invarg("invalid TTL", *argv);
	hop_limit = uval;
	} else if (!matches(*argv, "tos") \|\|
	!matches(*argv, "tclass") \|\|
	!matches(*argv, "dsfield")) {
	__u8 uval;
	NEXT_ARG();
	if (strcmp(*argv, "inherit") == 0)
	flags \|= IP6_TNL_F_USE_ORIG_TCLASS;
	else {
	if (get_u8(&uval, *argv, 16))
	invarg("invalid TClass", *argv);
	flowinfo \|= htonl((__u32)uval << 20) & IP6_FLOWINFO_TCLASS;
	flags &= ~IP6_TNL_F_USE_ORIG_TCLASS;
	}
	} else if (strcmp(*argv, "flowlabel") == 0 \|\|
	strcmp(*argv, "fl") == 0) {
	__u32 uval;
	NEXT_ARG();
	if (strcmp(*argv, "inherit") == 0)
	flags \|= IP6_TNL_F_USE_ORIG_FLOWLABEL;
	else {
	if (get_u32(&uval, *argv, 16))
	invarg("invalid Flowlabel", *argv);
	if (uval > 0xFFFFF)
	invarg("invalid Flowlabel", *argv);
	flowinfo \|= htonl(uval) & IP6_FLOWINFO_FLOWLABEL;
	flags &= ~IP6_TNL_F_USE_ORIG_FLOWLABEL;
	}
	} else if (strcmp(*argv, "dscp") == 0) {
	NEXT_ARG();
	if (strcmp(*argv, "inherit") != 0)
	invarg("not inherit", *argv);
	flags \|= IP6_TNL_F_RCV_DSCP_COPY;
	} else
	usage();
	argc--; argv++;
	}

	addattr32(n, 1024, IFLA_GRE_IKEY, ikey);
	addattr32(n, 1024, IFLA_GRE_OKEY, okey);
	addattr_l(n, 1024, IFLA_GRE_IFLAGS, &iflags, 2);
	addattr_l(n, 1024, IFLA_GRE_OFLAGS, &oflags, 2);
	addattr_l(n, 1024, IFLA_GRE_LOCAL, &laddr, sizeof(laddr));
	addattr_l(n, 1024, IFLA_GRE_REMOTE, &raddr, sizeof(raddr));
	if (link)
	addattr32(n, 1024, IFLA_GRE_LINK, link);
	addattr_l(n, 1024, IFLA_GRE_TTL, &hop_limit, 1);
	addattr_l(n, 1024, IFLA_GRE_ENCAP_LIMIT, &encap_limit, 1);
	addattr_l(n, 1024, IFLA_GRE_FLOWINFO, &flowinfo, 4);
	addattr_l(n, 1024, IFLA_GRE_FLAGS, &flowinfo, 4);

	return 0;
	}

	static void gre_print_opt(struct link_util lu, FILE f, struct rtattr *tb[])
	{
	char s1[1024];
	char s2[64];
	const char *local = "any";
	const char *remote = "any";
	unsigned iflags = 0;
	unsigned oflags = 0;
	unsigned flags = 0;
	unsigned flowinfo = 0;
	struct in6_addr in6_addr_any = IN6ADDR_ANY_INIT;

	if (!tb)
	return;

	if (tb[IFLA_GRE_FLAGS])
	flags = rta_getattr_u32(tb[IFLA_GRE_FLAGS]);

	if (tb[IFLA_GRE_FLOWINFO])
	flags = rta_getattr_u32(tb[IFLA_GRE_FLOWINFO]);

	if (tb[IFLA_GRE_REMOTE]) {
	struct in6_addr addr;
	memcpy(&addr, RTA_DATA(tb[IFLA_GRE_REMOTE]), sizeof(addr));

	if (memcmp(&addr, &in6_addr_any, sizeof(addr)))
	remote = format_host(AF_INET6, sizeof(addr), &addr, s1, sizeof(s1));
	}

	fprintf(f, "remote %s ", remote);

	if (tb[IFLA_GRE_LOCAL]) {
	struct in6_addr addr;
	memcpy(&addr, RTA_DATA(tb[IFLA_GRE_LOCAL]), sizeof(addr));

	if (memcmp(&addr, &in6_addr_any, sizeof(addr)))
	local = format_host(AF_INET6, sizeof(addr), &addr, s1, sizeof(s1));
	}

	fprintf(f, "local %s ", local);

	if (tb[IFLA_GRE_LINK] && rta_getattr_u32(tb[IFLA_GRE_LINK])) {
	unsigned link = rta_getattr_u32(tb[IFLA_GRE_LINK]);
	const char *n = if_indextoname(link, s2);

	if (n)
	fprintf(f, "dev %s ", n);
	else
	fprintf(f, "dev %u ", link);
	}

	if (tb[IFLA_GRE_TTL] && rta_getattr_u8(tb[IFLA_GRE_TTL]))
	fprintf(f, "hoplimit %d ", rta_getattr_u8(tb[IFLA_GRE_TTL]));

	if (flags & IP6_TNL_F_IGN_ENCAP_LIMIT)
	fprintf(f, "encaplimit none ");
	else if (tb[IFLA_GRE_ENCAP_LIMIT]) {
	int encap_limit = rta_getattr_u8(tb[IFLA_GRE_ENCAP_LIMIT]);

	fprintf(f, "encaplimit %d ", encap_limit);
	}

	if (flags & IP6_TNL_F_USE_ORIG_FLOWLABEL)
	fprintf(f, "flowlabel inherit ");
	else
	fprintf(f, "flowlabel 0x%05x ", ntohl(flowinfo & IP6_FLOWINFO_FLOWLABEL));

	if (flags & IP6_TNL_F_RCV_DSCP_COPY)
	fprintf(f, "dscp inherit ");

	if (tb[IFLA_GRE_IFLAGS])
	iflags = rta_getattr_u16(tb[IFLA_GRE_IFLAGS]);

	if (tb[IFLA_GRE_OFLAGS])
	oflags = rta_getattr_u16(tb[IFLA_GRE_OFLAGS]);

	if ((iflags & GRE_KEY) && tb[IFLA_GRE_IKEY]) {
	inet_ntop(AF_INET, RTA_DATA(tb[IFLA_GRE_IKEY]), s2, sizeof(s2));
	fprintf(f, "ikey %s ", s2);
	}

	if ((oflags & GRE_KEY) && tb[IFLA_GRE_OKEY]) {
	inet_ntop(AF_INET, RTA_DATA(tb[IFLA_GRE_OKEY]), s2, sizeof(s2));
	fprintf(f, "okey %s ", s2);
	}

	if (iflags & GRE_SEQ)
	fputs("iseq ", f);
	if (oflags & GRE_SEQ)
	fputs("oseq ", f);
	if (iflags & GRE_CSUM)
	fputs("icsum ", f);
	if (oflags & GRE_CSUM)
	fputs("ocsum ", f);
	}

	struct link_util ip6gre_link_util = {
	.id = "ip6gre",
	.maxattr = IFLA_GRE_MAX,
	.parse_opt = gre_parse_opt,
	.print_opt = gre_print_opt,
	};

	struct link_util ip6gretap_link_util = {
	.id = "ip6gretap",
	.maxattr = IFLA_GRE_MAX,
	.parse_opt = gre_parse_opt,
	.print_opt = gre_print_opt,
	};