ip/link_gre.c - platform/external/iproute2 - Git at Google

 /*
  * link_gre.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:	Herbert Xu <herbert@gondor.apana.org.au>
  *
  */

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

 static void print_usage(FILE *f)
 {
 	fprintf(f,
 		"Usage: ... { gre | gretap | erspan } [ remote ADDR ]\n"
 		"                            [ local ADDR ]\n"
 		"                            [ [i|o]seq ]\n"
 		"                            [ [i|o]key KEY ]\n"
 		"                            [ [i|o]csum ]\n"
 		"                            [ ttl TTL ]\n"
 		"                            [ tos TOS ]\n"
 		"                            [ [no]pmtudisc ]\n"
 		"                            [ [no]ignore-df ]\n"
 		"                            [ dev PHYS_DEV ]\n"
 		"                            [ noencap ]\n"
 		"                            [ encap { fou | gue | none } ]\n"
 		"                            [ encap-sport PORT ]\n"
 		"                            [ encap-dport PORT ]\n"
 		"                            [ [no]encap-csum ]\n"
 		"                            [ [no]encap-csum6 ]\n"
 		"                            [ [no]encap-remcsum ]\n"
 		"                            [ fwmark MARK ]\n"
 		"                            [ erspan IDX ]\n"
 		"\n"
 		"Where: ADDR := { IP_ADDRESS | any }\n"
 		"       TOS  := { NUMBER | inherit }\n"
 		"       TTL  := { 1..255 | inherit }\n"
 		"       KEY  := { DOTTED_QUAD | NUMBER }\n"
 		"       MARK := { 0x0..0xffffffff }\n"
 	);
 }

 static void usage(void) __attribute__((noreturn));
 static void usage(void)
 {
 	print_usage(stderr);
 	exit(-1);
 }

 static int gre_parse_opt(struct link_util *lu, int argc, char **argv,
 			 struct nlmsghdr *n)
 {
 	struct ifinfomsg *ifi = (struct ifinfomsg *)(n + 1);
 	struct {
 		struct nlmsghdr n;
 		struct ifinfomsg i;
 		char buf[16384];
 	} req = {
 		.n.nlmsg_len = NLMSG_LENGTH(sizeof(*ifi)),
 		.n.nlmsg_flags = NLM_F_REQUEST,
 		.n.nlmsg_type = RTM_GETLINK,
 		.i.ifi_family = preferred_family,
 		.i.ifi_index = ifi->ifi_index,
 	};
 	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 int ikey = 0;
 	unsigned int okey = 0;
 	unsigned int saddr = 0;
 	unsigned int daddr = 0;
 	unsigned int link = 0;
 	__u8 pmtudisc = 1;
 	__u8 ttl = 0;
 	__u8 tos = 0;
 	int len;
 	__u16 encaptype = 0;
 	__u16 encapflags = 0;
 	__u16 encapsport = 0;
 	__u16 encapdport = 0;
 	__u8 metadata = 0;
 	__u8 ignore_df = 0;
 	__u32 fwmark = 0;
 	__u32 erspan_idx = 0;

 	if (!(n->nlmsg_flags & NLM_F_CREATE)) {
 		if (rtnl_talk(&rth, &req.n, &req.n, sizeof(req)) < 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])
 			saddr = rta_getattr_u32(greinfo[IFLA_GRE_LOCAL]);

 		if (greinfo[IFLA_GRE_REMOTE])
 			daddr = rta_getattr_u32(greinfo[IFLA_GRE_REMOTE]);

 		if (greinfo[IFLA_GRE_PMTUDISC])
 			pmtudisc = rta_getattr_u8(
 				greinfo[IFLA_GRE_PMTUDISC]);

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

 		if (greinfo[IFLA_GRE_TOS])
 			tos = rta_getattr_u8(greinfo[IFLA_GRE_TOS]);

 		if (greinfo[IFLA_GRE_LINK])
 			link = rta_getattr_u8(greinfo[IFLA_GRE_LINK]);

 		if (greinfo[IFLA_GRE_ENCAP_TYPE])
 			encaptype = rta_getattr_u16(greinfo[IFLA_GRE_ENCAP_TYPE]);
 		if (greinfo[IFLA_GRE_ENCAP_FLAGS])
 			encapflags = rta_getattr_u16(greinfo[IFLA_GRE_ENCAP_FLAGS]);
 		if (greinfo[IFLA_GRE_ENCAP_SPORT])
 			encapsport = rta_getattr_u16(greinfo[IFLA_GRE_ENCAP_SPORT]);
 		if (greinfo[IFLA_GRE_ENCAP_DPORT])
 			encapdport = rta_getattr_u16(greinfo[IFLA_GRE_ENCAP_DPORT]);

 		if (greinfo[IFLA_GRE_COLLECT_METADATA])
 			metadata = 1;

 		if (greinfo[IFLA_GRE_IGNORE_DF])
 			ignore_df =
 				!!rta_getattr_u8(greinfo[IFLA_GRE_IGNORE_DF]);

 		if (greinfo[IFLA_GRE_FWMARK])
 			fwmark = rta_getattr_u32(greinfo[IFLA_GRE_FWMARK]);

 		if (greinfo[IFLA_GRE_ERSPAN_INDEX])
 			erspan_idx = rta_getattr_u32(greinfo[IFLA_GRE_ERSPAN_INDEX]);
 	}

 	while (argc > 0) {
 		if (!matches(*argv, "key")) {
 			unsigned int 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\": \"%s\"; it should be an unsigned integer\n", *argv);
 					exit(-1);
 				}
 				uval = htonl(uval);
 			}

 			ikey = okey = uval;
 		} else if (!matches(*argv, "ikey")) {
 			unsigned int 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 for \"ikey\": \"%s\"; it should be an unsigned integer\n", *argv);
 					exit(-1);
 				}
 				uval = htonl(uval);
 			}
 			ikey = uval;
 		} else if (!matches(*argv, "okey")) {
 			unsigned int 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 for \"okey\": \"%s\"; it should be an unsigned integer\n", *argv);
 					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, "nopmtudisc")) {
 			pmtudisc = 0;
 		} else if (!matches(*argv, "pmtudisc")) {
 			pmtudisc = 1;
 		} else if (!matches(*argv, "remote")) {
 			NEXT_ARG();
 			if (strcmp(*argv, "any"))
 				daddr = get_addr32(*argv);
 		} else if (!matches(*argv, "local")) {
 			NEXT_ARG();
 			if (strcmp(*argv, "any"))
 				saddr = get_addr32(*argv);
 		} else if (!matches(*argv, "dev")) {
 			NEXT_ARG();
 			link = if_nametoindex(*argv);
 			if (link == 0) {
 				fprintf(stderr, "Cannot find device \"%s\"\n",
 					*argv);
 				exit(-1);
 			}
 		} else if (!matches(*argv, "ttl") ||
 			   !matches(*argv, "hoplimit")) {
 			unsigned int uval;

 			NEXT_ARG();
 			if (strcmp(*argv, "inherit") != 0) {
 				if (get_unsigned(&uval, *argv, 0))
 					invarg("invalid TTL\n", *argv);
 				if (uval > 255)
 					invarg("TTL must be <= 255\n", *argv);
 				ttl = uval;
 			}
 		} else if (!matches(*argv, "tos") ||
 			   !matches(*argv, "tclass") ||
 			   !matches(*argv, "dsfield")) {
 			__u32 uval;

 			NEXT_ARG();
 			if (strcmp(*argv, "inherit") != 0) {
 				if (rtnl_dsfield_a2n(&uval, *argv))
 					invarg("bad TOS value", *argv);
 				tos = uval;
 			} else
 				tos = 1;
 		} else if (strcmp(*argv, "noencap") == 0) {
 			encaptype = TUNNEL_ENCAP_NONE;
 		} else if (strcmp(*argv, "encap") == 0) {
 			NEXT_ARG();
 			if (strcmp(*argv, "fou") == 0)
 				encaptype = TUNNEL_ENCAP_FOU;
 			else if (strcmp(*argv, "gue") == 0)
 				encaptype = TUNNEL_ENCAP_GUE;
 			else if (strcmp(*argv, "none") == 0)
 				encaptype = TUNNEL_ENCAP_NONE;
 			else
 				invarg("Invalid encap type.", *argv);
 		} else if (strcmp(*argv, "encap-sport") == 0) {
 			NEXT_ARG();
 			if (strcmp(*argv, "auto") == 0)
 				encapsport = 0;
 			else if (get_u16(&encapsport, *argv, 0))
 				invarg("Invalid source port.", *argv);
 		} else if (strcmp(*argv, "encap-dport") == 0) {
 			NEXT_ARG();
 			if (get_u16(&encapdport, *argv, 0))
 				invarg("Invalid destination port.", *argv);
 		} else if (strcmp(*argv, "encap-csum") == 0) {
 			encapflags |= TUNNEL_ENCAP_FLAG_CSUM;
 		} else if (strcmp(*argv, "noencap-csum") == 0) {
 			encapflags &= ~TUNNEL_ENCAP_FLAG_CSUM;
 		} else if (strcmp(*argv, "encap-udp6-csum") == 0) {
 			encapflags |= TUNNEL_ENCAP_FLAG_CSUM6;
 		} else if (strcmp(*argv, "noencap-udp6-csum") == 0) {
 			encapflags |= ~TUNNEL_ENCAP_FLAG_CSUM6;
 		} else if (strcmp(*argv, "encap-remcsum") == 0) {
 			encapflags |= TUNNEL_ENCAP_FLAG_REMCSUM;
 		} else if (strcmp(*argv, "noencap-remcsum") == 0) {
 			encapflags |= ~TUNNEL_ENCAP_FLAG_REMCSUM;
 		} else if (strcmp(*argv, "external") == 0) {
 			metadata = 1;
 		} else if (strcmp(*argv, "ignore-df") == 0) {
 			ignore_df = 1;
 		} else if (strcmp(*argv, "noignore-df") == 0) {
 			/*
 			 *only the lsb is significant, use 2 for presence
 			 */
 			ignore_df = 2;
 		} else if (strcmp(*argv, "fwmark") == 0) {
 			NEXT_ARG();
 			if (get_u32(&fwmark, *argv, 0))
 				invarg("invalid fwmark\n", *argv);
 		} else if (strcmp(*argv, "erspan") == 0) {
 			NEXT_ARG();
 			if (get_u32(&erspan_idx, *argv, 0))
 				invarg("invalid erspan index\n", *argv);
 			if (erspan_idx & ~((1<<20) - 1) || erspan_idx == 0)
 				invarg("erspan index must be > 0 and <= 20-bit\n", *argv);
 		} else
 			usage();
 		argc--; argv++;
 	}

 	if (!ikey && IN_MULTICAST(ntohl(daddr))) {
 		ikey = daddr;
 		iflags |= GRE_KEY;
 	}
 	if (!okey && IN_MULTICAST(ntohl(daddr))) {
 		okey = daddr;
 		oflags |= GRE_KEY;
 	}
 	if (IN_MULTICAST(ntohl(daddr)) && !saddr) {
 		fprintf(stderr, "A broadcast tunnel requires a source address.\n");
 		return -1;
 	}

 	if (!metadata) {
 		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, &saddr, 4);
 		addattr_l(n, 1024, IFLA_GRE_REMOTE, &daddr, 4);
 		addattr_l(n, 1024, IFLA_GRE_PMTUDISC, &pmtudisc, 1);
 		if (link)
 			addattr32(n, 1024, IFLA_GRE_LINK, link);
 		addattr_l(n, 1024, IFLA_GRE_TTL, &ttl, 1);
 		addattr_l(n, 1024, IFLA_GRE_TOS, &tos, 1);
 		addattr32(n, 1024, IFLA_GRE_FWMARK, fwmark);
 		if (erspan_idx != 0)
 			addattr32(n, 1024, IFLA_GRE_ERSPAN_INDEX, erspan_idx);
 	} else {
 		addattr_l(n, 1024, IFLA_GRE_COLLECT_METADATA, NULL, 0);
 	}

 	addattr16(n, 1024, IFLA_GRE_ENCAP_TYPE, encaptype);
 	addattr16(n, 1024, IFLA_GRE_ENCAP_FLAGS, encapflags);
 	addattr16(n, 1024, IFLA_GRE_ENCAP_SPORT, htons(encapsport));
 	addattr16(n, 1024, IFLA_GRE_ENCAP_DPORT, htons(encapdport));

 	if (ignore_df)
 		addattr8(n, 1024, IFLA_GRE_IGNORE_DF, ignore_df & 1);

 	return 0;
 }

 static void gre_print_direct_opt(FILE *f, struct rtattr *tb[])
 {
 	char s2[64];
 	const char *local = "any";
 	const char *remote = "any";
 	unsigned int iflags = 0;
 	unsigned int oflags = 0;

 	if (tb[IFLA_GRE_REMOTE]) {
 		unsigned int addr = rta_getattr_u32(tb[IFLA_GRE_REMOTE]);

 		if (addr)
 			remote = format_host(AF_INET, 4, &addr);
 	}

 	print_string(PRINT_ANY, "remote", "remote %s ", remote);

 	if (tb[IFLA_GRE_LOCAL]) {
 		unsigned int addr = rta_getattr_u32(tb[IFLA_GRE_LOCAL]);

 		if (addr)
 			local = format_host(AF_INET, 4, &addr);
 	}

 	print_string(PRINT_ANY, "local", "local %s ", local);

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

 		if (n)
 			print_string(PRINT_ANY, "link", "dev %s ", n);
 		else
 			print_uint(PRINT_ANY, "link_index", "dev %u ", link);
 	}

 	if (tb[IFLA_GRE_TTL]) {
 		__u8 ttl = rta_getattr_u8(tb[IFLA_GRE_TTL]);

 		if (ttl)
 			print_int(PRINT_ANY, "ttl", "ttl %d ", ttl);
 		else
 			print_int(PRINT_JSON, "ttl", NULL, ttl);
 	} else {
 		print_string(PRINT_FP, NULL, "ttl %s ", "inherit");
 	}

 	if (tb[IFLA_GRE_TOS] && rta_getattr_u8(tb[IFLA_GRE_TOS])) {
 		int tos = rta_getattr_u8(tb[IFLA_GRE_TOS]);

 		if (is_json_context()) {
 			SPRINT_BUF(b1);

 			snprintf(b1, sizeof(b1), "0x%x", tos);
 			print_string(PRINT_JSON, "tos", NULL, b1);
 		} else {
 			fputs("tos ", f);
 			if (tos == 1)
 				fputs("inherit ", f);
 			else
 				fprintf(f, "0x%x ", tos);
 		}
 	}

 	if (tb[IFLA_GRE_PMTUDISC]) {
 		if (!rta_getattr_u8(tb[IFLA_GRE_PMTUDISC]))
 			print_bool(PRINT_ANY, "pmtudisc", "nopmtudisc ", false);
 		else
 			print_bool(PRINT_JSON, "pmtudisc", NULL, true);
 	}

 	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));
 		print_string(PRINT_ANY, "ikey", "ikey %s ", s2);
 	}

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

 	if (iflags & GRE_SEQ)
 		print_bool(PRINT_ANY, "iseq", "iseq ", true);
 	if (oflags & GRE_SEQ)
 		print_bool(PRINT_ANY, "oseq", "oseq ", true);
 	if (iflags & GRE_CSUM)
 		print_bool(PRINT_ANY, "icsum", "icsum ", true);
 	if (oflags & GRE_CSUM)
 		print_bool(PRINT_ANY, "ocsum", "ocsum ", true);

 	if (tb[IFLA_GRE_FWMARK]) {
 		__u32 fwmark = rta_getattr_u32(tb[IFLA_GRE_FWMARK]);

 		if (fwmark) {
 			snprintf(s2, sizeof(s2), "0x%x", fwmark);

 			print_string(PRINT_ANY, "fwmark", "fwmark %s ", s2);
 		}
 	}
 }

 static void gre_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
 {
 	if (!tb)
 		return;

 	if (!tb[IFLA_GRE_COLLECT_METADATA])
 		gre_print_direct_opt(f, tb);
 	else
 		print_bool(PRINT_ANY, "external", "external ", true);

 	if (tb[IFLA_GRE_IGNORE_DF] && rta_getattr_u8(tb[IFLA_GRE_IGNORE_DF]))
 		print_bool(PRINT_ANY, "ignore_df", "ignore-df ", true);

 	if (tb[IFLA_GRE_ERSPAN_INDEX]) {
 		__u32 erspan_idx = rta_getattr_u32(tb[IFLA_GRE_ERSPAN_INDEX]);

 		fprintf(f, "erspan_index %u ", erspan_idx);
 	}

 	if (tb[IFLA_GRE_ENCAP_TYPE] &&
 	    rta_getattr_u16(tb[IFLA_GRE_ENCAP_TYPE]) != TUNNEL_ENCAP_NONE) {
 		__u16 type = rta_getattr_u16(tb[IFLA_GRE_ENCAP_TYPE]);
 		__u16 flags = rta_getattr_u16(tb[IFLA_GRE_ENCAP_FLAGS]);
 		__u16 sport = rta_getattr_u16(tb[IFLA_GRE_ENCAP_SPORT]);
 		__u16 dport = rta_getattr_u16(tb[IFLA_GRE_ENCAP_DPORT]);


 		open_json_object("encap");
 		print_string(PRINT_FP, NULL, "encap ", NULL);

 		switch (type) {
 		case TUNNEL_ENCAP_FOU:
 			print_string(PRINT_ANY, "type", "%s ", "fou");
 			break;
 		case TUNNEL_ENCAP_GUE:
 			print_string(PRINT_ANY, "type", "%s ", "gue");
 			break;
 		default:
 			print_null(PRINT_ANY, "type", "%s ", "unknown");
 			break;
 		}

 		if (is_json_context()) {
 			print_uint(PRINT_JSON,
 				   "sport",
 				   NULL,
 				   sport ? ntohs(sport) : 0);
 			print_uint(PRINT_JSON, "dport", NULL, ntohs(dport));

 			print_bool(PRINT_JSON,
 				   "csum",
 				   NULL,
 				   flags & TUNNEL_ENCAP_FLAG_CSUM);

 			print_bool(PRINT_JSON,
 				   "csum6",
 				   NULL,
 				   flags & TUNNEL_ENCAP_FLAG_CSUM6);

 			print_bool(PRINT_JSON,
 				   "remcsum",
 				   NULL,
 				   flags & TUNNEL_ENCAP_FLAG_REMCSUM);

 			close_json_object();
 		} else {
 			if (sport == 0)
 				fputs("encap-sport auto ", f);
 			else
 				fprintf(f, "encap-sport %u", ntohs(sport));

 			fprintf(f, "encap-dport %u ", ntohs(dport));

 			if (flags & TUNNEL_ENCAP_FLAG_CSUM)
 				fputs("encap-csum ", f);
 			else
 				fputs("noencap-csum ", f);

 			if (flags & TUNNEL_ENCAP_FLAG_CSUM6)
 				fputs("encap-csum6 ", f);
 			else
 				fputs("noencap-csum6 ", f);

 			if (flags & TUNNEL_ENCAP_FLAG_REMCSUM)
 				fputs("encap-remcsum ", f);
 			else
 				fputs("noencap-remcsum ", f);
 		}
 	}
 }

 static void gre_print_help(struct link_util *lu, int argc, char **argv,
 			   FILE *f)
 {
 	print_usage(f);
 }

 struct link_util gre_link_util = {
 	.id = "gre",
 	.maxattr = IFLA_GRE_MAX,
 	.parse_opt = gre_parse_opt,
 	.print_opt = gre_print_opt,
 	.print_help = gre_print_help,
 };

 struct link_util gretap_link_util = {
 	.id = "gretap",
 	.maxattr = IFLA_GRE_MAX,
 	.parse_opt = gre_parse_opt,
 	.print_opt = gre_print_opt,
 	.print_help = gre_print_help,
 };

 struct link_util erspan_link_util = {
 	.id = "erspan",
 	.maxattr = IFLA_GRE_MAX,
 	.parse_opt = gre_parse_opt,
 	.print_opt = gre_print_opt,
 	.print_help = gre_print_help,
 };
	/*
	* link_gre.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: Herbert Xu <herbert@gondor.apana.org.au>
	*
	*/

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

	static void print_usage(FILE *f)
	{
	fprintf(f,
	"Usage: ... { gre \| gretap \| erspan } [ remote ADDR ]\n"
	" [ local ADDR ]\n"
	" [ [i\|o]seq ]\n"
	" [ [i\|o]key KEY ]\n"
	" [ [i\|o]csum ]\n"
	" [ ttl TTL ]\n"
	" [ tos TOS ]\n"
	" [ [no]pmtudisc ]\n"
	" [ [no]ignore-df ]\n"
	" [ dev PHYS_DEV ]\n"
	" [ noencap ]\n"
	" [ encap { fou \| gue \| none } ]\n"
	" [ encap-sport PORT ]\n"
	" [ encap-dport PORT ]\n"
	" [ [no]encap-csum ]\n"
	" [ [no]encap-csum6 ]\n"
	" [ [no]encap-remcsum ]\n"
	" [ fwmark MARK ]\n"
	" [ erspan IDX ]\n"
	"\n"
	"Where: ADDR := { IP_ADDRESS \| any }\n"
	" TOS := { NUMBER \| inherit }\n"
	" TTL := { 1..255 \| inherit }\n"
	" KEY := { DOTTED_QUAD \| NUMBER }\n"
	" MARK := { 0x0..0xffffffff }\n"
	);
	}

	static void usage(void) __attribute__((noreturn));
	static void usage(void)
	{
	print_usage(stderr);
	exit(-1);
	}

	static int gre_parse_opt(struct link_util lu, int argc, char *argv,
	struct nlmsghdr *n)
	{
	struct ifinfomsg ifi = (struct ifinfomsg )(n + 1);
	struct {
	struct nlmsghdr n;
	struct ifinfomsg i;
	char buf[16384];
	} req = {
	.n.nlmsg_len = NLMSG_LENGTH(sizeof(*ifi)),
	.n.nlmsg_flags = NLM_F_REQUEST,
	.n.nlmsg_type = RTM_GETLINK,
	.i.ifi_family = preferred_family,
	.i.ifi_index = ifi->ifi_index,
	};
	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 int ikey = 0;
	unsigned int okey = 0;
	unsigned int saddr = 0;
	unsigned int daddr = 0;
	unsigned int link = 0;
	__u8 pmtudisc = 1;
	__u8 ttl = 0;
	__u8 tos = 0;
	int len;
	__u16 encaptype = 0;
	__u16 encapflags = 0;
	__u16 encapsport = 0;
	__u16 encapdport = 0;
	__u8 metadata = 0;
	__u8 ignore_df = 0;
	__u32 fwmark = 0;
	__u32 erspan_idx = 0;

	if (!(n->nlmsg_flags & NLM_F_CREATE)) {
	if (rtnl_talk(&rth, &req.n, &req.n, sizeof(req)) < 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])
	saddr = rta_getattr_u32(greinfo[IFLA_GRE_LOCAL]);

	if (greinfo[IFLA_GRE_REMOTE])
	daddr = rta_getattr_u32(greinfo[IFLA_GRE_REMOTE]);

	if (greinfo[IFLA_GRE_PMTUDISC])
	pmtudisc = rta_getattr_u8(
	greinfo[IFLA_GRE_PMTUDISC]);

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

	if (greinfo[IFLA_GRE_TOS])
	tos = rta_getattr_u8(greinfo[IFLA_GRE_TOS]);

	if (greinfo[IFLA_GRE_LINK])
	link = rta_getattr_u8(greinfo[IFLA_GRE_LINK]);

	if (greinfo[IFLA_GRE_ENCAP_TYPE])
	encaptype = rta_getattr_u16(greinfo[IFLA_GRE_ENCAP_TYPE]);
	if (greinfo[IFLA_GRE_ENCAP_FLAGS])
	encapflags = rta_getattr_u16(greinfo[IFLA_GRE_ENCAP_FLAGS]);
	if (greinfo[IFLA_GRE_ENCAP_SPORT])
	encapsport = rta_getattr_u16(greinfo[IFLA_GRE_ENCAP_SPORT]);
	if (greinfo[IFLA_GRE_ENCAP_DPORT])
	encapdport = rta_getattr_u16(greinfo[IFLA_GRE_ENCAP_DPORT]);

	if (greinfo[IFLA_GRE_COLLECT_METADATA])
	metadata = 1;

	if (greinfo[IFLA_GRE_IGNORE_DF])
	ignore_df =
	!!rta_getattr_u8(greinfo[IFLA_GRE_IGNORE_DF]);

	if (greinfo[IFLA_GRE_FWMARK])
	fwmark = rta_getattr_u32(greinfo[IFLA_GRE_FWMARK]);

	if (greinfo[IFLA_GRE_ERSPAN_INDEX])
	erspan_idx = rta_getattr_u32(greinfo[IFLA_GRE_ERSPAN_INDEX]);
	}

	while (argc > 0) {
	if (!matches(*argv, "key")) {
	unsigned int 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\": \"%s\"; it should be an unsigned integer\n", *argv);
	exit(-1);
	}
	uval = htonl(uval);
	}

	ikey = okey = uval;
	} else if (!matches(*argv, "ikey")) {
	unsigned int 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 for \"ikey\": \"%s\"; it should be an unsigned integer\n", *argv);
	exit(-1);
	}
	uval = htonl(uval);
	}
	ikey = uval;
	} else if (!matches(*argv, "okey")) {
	unsigned int 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 for \"okey\": \"%s\"; it should be an unsigned integer\n", *argv);
	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, "nopmtudisc")) {
	pmtudisc = 0;
	} else if (!matches(*argv, "pmtudisc")) {
	pmtudisc = 1;
	} else if (!matches(*argv, "remote")) {
	NEXT_ARG();
	if (strcmp(*argv, "any"))
	daddr = get_addr32(*argv);
	} else if (!matches(*argv, "local")) {
	NEXT_ARG();
	if (strcmp(*argv, "any"))
	saddr = get_addr32(*argv);
	} else if (!matches(*argv, "dev")) {
	NEXT_ARG();
	link = if_nametoindex(*argv);
	if (link == 0) {
	fprintf(stderr, "Cannot find device \"%s\"\n",
	*argv);
	exit(-1);
	}
	} else if (!matches(*argv, "ttl") \|\|
	!matches(*argv, "hoplimit")) {
	unsigned int uval;

	NEXT_ARG();
	if (strcmp(*argv, "inherit") != 0) {
	if (get_unsigned(&uval, *argv, 0))
	invarg("invalid TTL\n", *argv);
	if (uval > 255)
	invarg("TTL must be <= 255\n", *argv);
	ttl = uval;
	}
	} else if (!matches(*argv, "tos") \|\|
	!matches(*argv, "tclass") \|\|
	!matches(*argv, "dsfield")) {
	__u32 uval;

	NEXT_ARG();
	if (strcmp(*argv, "inherit") != 0) {
	if (rtnl_dsfield_a2n(&uval, *argv))
	invarg("bad TOS value", *argv);
	tos = uval;
	} else
	tos = 1;
	} else if (strcmp(*argv, "noencap") == 0) {
	encaptype = TUNNEL_ENCAP_NONE;
	} else if (strcmp(*argv, "encap") == 0) {
	NEXT_ARG();
	if (strcmp(*argv, "fou") == 0)
	encaptype = TUNNEL_ENCAP_FOU;
	else if (strcmp(*argv, "gue") == 0)
	encaptype = TUNNEL_ENCAP_GUE;
	else if (strcmp(*argv, "none") == 0)
	encaptype = TUNNEL_ENCAP_NONE;
	else
	invarg("Invalid encap type.", *argv);
	} else if (strcmp(*argv, "encap-sport") == 0) {
	NEXT_ARG();
	if (strcmp(*argv, "auto") == 0)
	encapsport = 0;
	else if (get_u16(&encapsport, *argv, 0))
	invarg("Invalid source port.", *argv);
	} else if (strcmp(*argv, "encap-dport") == 0) {
	NEXT_ARG();
	if (get_u16(&encapdport, *argv, 0))
	invarg("Invalid destination port.", *argv);
	} else if (strcmp(*argv, "encap-csum") == 0) {
	encapflags \|= TUNNEL_ENCAP_FLAG_CSUM;
	} else if (strcmp(*argv, "noencap-csum") == 0) {
	encapflags &= ~TUNNEL_ENCAP_FLAG_CSUM;
	} else if (strcmp(*argv, "encap-udp6-csum") == 0) {
	encapflags \|= TUNNEL_ENCAP_FLAG_CSUM6;
	} else if (strcmp(*argv, "noencap-udp6-csum") == 0) {
	encapflags \|= ~TUNNEL_ENCAP_FLAG_CSUM6;
	} else if (strcmp(*argv, "encap-remcsum") == 0) {
	encapflags \|= TUNNEL_ENCAP_FLAG_REMCSUM;
	} else if (strcmp(*argv, "noencap-remcsum") == 0) {
	encapflags \|= ~TUNNEL_ENCAP_FLAG_REMCSUM;
	} else if (strcmp(*argv, "external") == 0) {
	metadata = 1;
	} else if (strcmp(*argv, "ignore-df") == 0) {
	ignore_df = 1;
	} else if (strcmp(*argv, "noignore-df") == 0) {
	/*
	*only the lsb is significant, use 2 for presence
	*/
	ignore_df = 2;
	} else if (strcmp(*argv, "fwmark") == 0) {
	NEXT_ARG();
	if (get_u32(&fwmark, *argv, 0))
	invarg("invalid fwmark\n", *argv);
	} else if (strcmp(*argv, "erspan") == 0) {
	NEXT_ARG();
	if (get_u32(&erspan_idx, *argv, 0))
	invarg("invalid erspan index\n", *argv);
	if (erspan_idx & ~((1<<20) - 1) \|\| erspan_idx == 0)
	invarg("erspan index must be > 0 and <= 20-bit\n", *argv);
	} else
	usage();
	argc--; argv++;
	}

	if (!ikey && IN_MULTICAST(ntohl(daddr))) {
	ikey = daddr;
	iflags \|= GRE_KEY;
	}
	if (!okey && IN_MULTICAST(ntohl(daddr))) {
	okey = daddr;
	oflags \|= GRE_KEY;
	}
	if (IN_MULTICAST(ntohl(daddr)) && !saddr) {
	fprintf(stderr, "A broadcast tunnel requires a source address.\n");
	return -1;
	}

	if (!metadata) {
	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, &saddr, 4);
	addattr_l(n, 1024, IFLA_GRE_REMOTE, &daddr, 4);
	addattr_l(n, 1024, IFLA_GRE_PMTUDISC, &pmtudisc, 1);
	if (link)
	addattr32(n, 1024, IFLA_GRE_LINK, link);
	addattr_l(n, 1024, IFLA_GRE_TTL, &ttl, 1);
	addattr_l(n, 1024, IFLA_GRE_TOS, &tos, 1);
	addattr32(n, 1024, IFLA_GRE_FWMARK, fwmark);
	if (erspan_idx != 0)
	addattr32(n, 1024, IFLA_GRE_ERSPAN_INDEX, erspan_idx);
	} else {
	addattr_l(n, 1024, IFLA_GRE_COLLECT_METADATA, NULL, 0);
	}

	addattr16(n, 1024, IFLA_GRE_ENCAP_TYPE, encaptype);
	addattr16(n, 1024, IFLA_GRE_ENCAP_FLAGS, encapflags);
	addattr16(n, 1024, IFLA_GRE_ENCAP_SPORT, htons(encapsport));
	addattr16(n, 1024, IFLA_GRE_ENCAP_DPORT, htons(encapdport));

	if (ignore_df)
	addattr8(n, 1024, IFLA_GRE_IGNORE_DF, ignore_df & 1);

	return 0;
	}

	static void gre_print_direct_opt(FILE f, struct rtattr tb[])
	{
	char s2[64];
	const char *local = "any";
	const char *remote = "any";
	unsigned int iflags = 0;
	unsigned int oflags = 0;

	if (tb[IFLA_GRE_REMOTE]) {
	unsigned int addr = rta_getattr_u32(tb[IFLA_GRE_REMOTE]);

	if (addr)
	remote = format_host(AF_INET, 4, &addr);
	}

	print_string(PRINT_ANY, "remote", "remote %s ", remote);

	if (tb[IFLA_GRE_LOCAL]) {
	unsigned int addr = rta_getattr_u32(tb[IFLA_GRE_LOCAL]);

	if (addr)
	local = format_host(AF_INET, 4, &addr);
	}

	print_string(PRINT_ANY, "local", "local %s ", local);

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

	if (n)
	print_string(PRINT_ANY, "link", "dev %s ", n);
	else
	print_uint(PRINT_ANY, "link_index", "dev %u ", link);
	}

	if (tb[IFLA_GRE_TTL]) {
	__u8 ttl = rta_getattr_u8(tb[IFLA_GRE_TTL]);

	if (ttl)
	print_int(PRINT_ANY, "ttl", "ttl %d ", ttl);
	else
	print_int(PRINT_JSON, "ttl", NULL, ttl);
	} else {
	print_string(PRINT_FP, NULL, "ttl %s ", "inherit");
	}

	if (tb[IFLA_GRE_TOS] && rta_getattr_u8(tb[IFLA_GRE_TOS])) {
	int tos = rta_getattr_u8(tb[IFLA_GRE_TOS]);

	if (is_json_context()) {
	SPRINT_BUF(b1);

	snprintf(b1, sizeof(b1), "0x%x", tos);
	print_string(PRINT_JSON, "tos", NULL, b1);
	} else {
	fputs("tos ", f);
	if (tos == 1)
	fputs("inherit ", f);
	else
	fprintf(f, "0x%x ", tos);
	}
	}

	if (tb[IFLA_GRE_PMTUDISC]) {
	if (!rta_getattr_u8(tb[IFLA_GRE_PMTUDISC]))
	print_bool(PRINT_ANY, "pmtudisc", "nopmtudisc ", false);
	else
	print_bool(PRINT_JSON, "pmtudisc", NULL, true);
	}

	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));
	print_string(PRINT_ANY, "ikey", "ikey %s ", s2);
	}

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

	if (iflags & GRE_SEQ)
	print_bool(PRINT_ANY, "iseq", "iseq ", true);
	if (oflags & GRE_SEQ)
	print_bool(PRINT_ANY, "oseq", "oseq ", true);
	if (iflags & GRE_CSUM)
	print_bool(PRINT_ANY, "icsum", "icsum ", true);
	if (oflags & GRE_CSUM)
	print_bool(PRINT_ANY, "ocsum", "ocsum ", true);

	if (tb[IFLA_GRE_FWMARK]) {
	__u32 fwmark = rta_getattr_u32(tb[IFLA_GRE_FWMARK]);

	if (fwmark) {
	snprintf(s2, sizeof(s2), "0x%x", fwmark);

	print_string(PRINT_ANY, "fwmark", "fwmark %s ", s2);
	}
	}
	}

	static void gre_print_opt(struct link_util lu, FILE f, struct rtattr *tb[])
	{
	if (!tb)
	return;

	if (!tb[IFLA_GRE_COLLECT_METADATA])
	gre_print_direct_opt(f, tb);
	else
	print_bool(PRINT_ANY, "external", "external ", true);

	if (tb[IFLA_GRE_IGNORE_DF] && rta_getattr_u8(tb[IFLA_GRE_IGNORE_DF]))
	print_bool(PRINT_ANY, "ignore_df", "ignore-df ", true);

	if (tb[IFLA_GRE_ERSPAN_INDEX]) {
	__u32 erspan_idx = rta_getattr_u32(tb[IFLA_GRE_ERSPAN_INDEX]);

	fprintf(f, "erspan_index %u ", erspan_idx);
	}

	if (tb[IFLA_GRE_ENCAP_TYPE] &&
	rta_getattr_u16(tb[IFLA_GRE_ENCAP_TYPE]) != TUNNEL_ENCAP_NONE) {
	__u16 type = rta_getattr_u16(tb[IFLA_GRE_ENCAP_TYPE]);
	__u16 flags = rta_getattr_u16(tb[IFLA_GRE_ENCAP_FLAGS]);
	__u16 sport = rta_getattr_u16(tb[IFLA_GRE_ENCAP_SPORT]);
	__u16 dport = rta_getattr_u16(tb[IFLA_GRE_ENCAP_DPORT]);


	open_json_object("encap");
	print_string(PRINT_FP, NULL, "encap ", NULL);

	switch (type) {
	case TUNNEL_ENCAP_FOU:
	print_string(PRINT_ANY, "type", "%s ", "fou");
	break;
	case TUNNEL_ENCAP_GUE:
	print_string(PRINT_ANY, "type", "%s ", "gue");
	break;
	default:
	print_null(PRINT_ANY, "type", "%s ", "unknown");
	break;
	}

	if (is_json_context()) {
	print_uint(PRINT_JSON,
	"sport",
	NULL,
	sport ? ntohs(sport) : 0);
	print_uint(PRINT_JSON, "dport", NULL, ntohs(dport));

	print_bool(PRINT_JSON,
	"csum",
	NULL,
	flags & TUNNEL_ENCAP_FLAG_CSUM);

	print_bool(PRINT_JSON,
	"csum6",
	NULL,
	flags & TUNNEL_ENCAP_FLAG_CSUM6);

	print_bool(PRINT_JSON,
	"remcsum",
	NULL,
	flags & TUNNEL_ENCAP_FLAG_REMCSUM);

	close_json_object();
	} else {
	if (sport == 0)
	fputs("encap-sport auto ", f);
	else
	fprintf(f, "encap-sport %u", ntohs(sport));

	fprintf(f, "encap-dport %u ", ntohs(dport));

	if (flags & TUNNEL_ENCAP_FLAG_CSUM)
	fputs("encap-csum ", f);
	else
	fputs("noencap-csum ", f);

	if (flags & TUNNEL_ENCAP_FLAG_CSUM6)
	fputs("encap-csum6 ", f);
	else
	fputs("noencap-csum6 ", f);

	if (flags & TUNNEL_ENCAP_FLAG_REMCSUM)
	fputs("encap-remcsum ", f);
	else
	fputs("noencap-remcsum ", f);
	}
	}
	}

	static void gre_print_help(struct link_util lu, int argc, char *argv,
	FILE *f)
	{
	print_usage(f);
	}

	struct link_util gre_link_util = {
	.id = "gre",
	.maxattr = IFLA_GRE_MAX,
	.parse_opt = gre_parse_opt,
	.print_opt = gre_print_opt,
	.print_help = gre_print_help,
	};

	struct link_util gretap_link_util = {
	.id = "gretap",
	.maxattr = IFLA_GRE_MAX,
	.parse_opt = gre_parse_opt,
	.print_opt = gre_print_opt,
	.print_help = gre_print_help,
	};

	struct link_util erspan_link_util = {
	.id = "erspan",
	.maxattr = IFLA_GRE_MAX,
	.parse_opt = gre_parse_opt,
	.print_opt = gre_print_opt,
	.print_help = gre_print_help,
	};