ip/link_iptnl.c - pub/scm/network/iproute2/iproute2-next - Git at Google

 /*
  * link_iptnl.c	ipip and sit 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:	Nicolas Dichtel <nicolas.dichtel@6wind.com>
  *
  */

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

 #include <linux/in.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 iptunnel_print_help(struct link_util *lu, int argc, char **argv,
 				FILE *f)
 {
 	const char *mode;

 	if (strcmp(lu->id, "sit") == 0) {
 		mode =	"{ ip6ip | ipip | mplsip | any } ]\n"
 			"			[ isatap";
 	} else {
 		mode = "{ ipip | mplsip | any }";
 	}

 	fprintf(f,
 		"Usage: ... %-6s	[ remote ADDR ]\n"
 		"			[ local ADDR ]\n"
 		"			[ ttl TTL ]\n"
 		"			[ tos TOS ]\n"
 		"			[ [no]pmtudisc ]\n"
 		"			[ 6rd-prefix ADDR ]\n"
 		"			[ 6rd-relay_prefix ADDR ]\n"
 		"			[ 6rd-reset ]\n"
 		"			[ dev PHYS_DEV ]\n"
 		"			[ fwmark MARK ]\n"
 		"			[ external ]\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"
 		"			[ mode %s ]\n"
 		"\n"
 		"Where:	ADDR := { IP_ADDRESS | any }\n"
 		"	TOS  := { NUMBER | inherit }\n"
 		"	TTL  := { 1..255 | inherit }\n"
 		"	MARK := { 0x0..0xffffffff }\n",
 		lu->id, mode);
 }

 static int iptunnel_parse_opt(struct link_util *lu, int argc, char **argv,
 			      struct nlmsghdr *n)
 {
 	struct ifinfomsg *ifi = NLMSG_DATA(n);
 	struct {
 		struct nlmsghdr n;
 		struct ifinfomsg i;
 	} 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 nlmsghdr *answer;
 	struct rtattr *tb[IFLA_MAX + 1];
 	struct rtattr *linkinfo[IFLA_INFO_MAX+1];
 	struct rtattr *iptuninfo[IFLA_IPTUN_MAX + 1];
 	int len;
 	inet_prefix saddr, daddr, ip6rdprefix, ip6rdrelayprefix;
 	__u8 pmtudisc = 1;
 	__u8 tos = 0;
 	__u16 iflags = 0;
 	__u8 ttl = 0;
 	__u8 proto = 0;
 	__u32 link = 0;
 	__u16 encaptype = 0;
 	__u16 encapflags = 0;
 	__u16 encapsport = 0;
 	__u16 encapdport = 0;
 	__u8 metadata = 0;
 	__u32 fwmark = 0;

 	inet_prefix_reset(&saddr);
 	inet_prefix_reset(&daddr);

 	inet_prefix_reset(&ip6rdprefix);
 	inet_prefix_reset(&ip6rdrelayprefix);

 	if (!(n->nlmsg_flags & NLM_F_CREATE)) {
 		const struct rtattr *rta;

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

 		len = answer->nlmsg_len;
 		len -= NLMSG_LENGTH(sizeof(*ifi));
 		if (len < 0)
 			goto get_failed;

 		parse_rtattr(tb, IFLA_MAX, IFLA_RTA(NLMSG_DATA(answer)), 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(iptuninfo, IFLA_IPTUN_MAX,
 				    linkinfo[IFLA_INFO_DATA]);

 		rta = iptuninfo[IFLA_IPTUN_LOCAL];
 		if (rta && get_addr_rta(&saddr, rta, AF_INET))
 			goto get_failed;

 		rta = iptuninfo[IFLA_IPTUN_REMOTE];
 		if (rta && get_addr_rta(&daddr, rta, AF_INET))
 			goto get_failed;

 		rta = iptuninfo[IFLA_IPTUN_6RD_PREFIX];
 		if (rta && get_addr_rta(&ip6rdprefix, rta, AF_INET6))
 			goto get_failed;

 		rta = iptuninfo[IFLA_IPTUN_6RD_RELAY_PREFIX];
 		if (rta && get_addr_rta(&ip6rdrelayprefix, rta, AF_INET))
 			goto get_failed;

 		rta = iptuninfo[IFLA_IPTUN_6RD_PREFIXLEN];
 		ip6rdprefix.bitlen = rta ? rta_getattr_u16(rta) : 0;

 		rta = iptuninfo[IFLA_IPTUN_6RD_RELAY_PREFIXLEN];
 		ip6rdrelayprefix.bitlen = rta ? rta_getattr_u16(rta) : 0;

 		if (iptuninfo[IFLA_IPTUN_TTL])
 			ttl = rta_getattr_u8(iptuninfo[IFLA_IPTUN_TTL]);

 		if (iptuninfo[IFLA_IPTUN_PMTUDISC])
 			pmtudisc =
 				rta_getattr_u8(iptuninfo[IFLA_IPTUN_PMTUDISC]);

 		if (iptuninfo[IFLA_IPTUN_TOS])
 			tos = rta_getattr_u8(iptuninfo[IFLA_IPTUN_TOS]);

 		if (iptuninfo[IFLA_IPTUN_FLAGS])
 			iflags = rta_getattr_u16(iptuninfo[IFLA_IPTUN_FLAGS]);

 		if (iptuninfo[IFLA_IPTUN_LINK])
 			link = rta_getattr_u32(iptuninfo[IFLA_IPTUN_LINK]);

 		if (iptuninfo[IFLA_IPTUN_PROTO])
 			proto = rta_getattr_u8(iptuninfo[IFLA_IPTUN_PROTO]);

 		if (iptuninfo[IFLA_IPTUN_ENCAP_TYPE])
 			encaptype = rta_getattr_u16(iptuninfo[IFLA_IPTUN_ENCAP_TYPE]);
 		if (iptuninfo[IFLA_IPTUN_ENCAP_FLAGS])
 			encapflags = rta_getattr_u16(iptuninfo[IFLA_IPTUN_ENCAP_FLAGS]);
 		if (iptuninfo[IFLA_IPTUN_ENCAP_SPORT])
 			encapsport = rta_getattr_u16(iptuninfo[IFLA_IPTUN_ENCAP_SPORT]);
 		if (iptuninfo[IFLA_IPTUN_ENCAP_DPORT])
 			encapdport = rta_getattr_u16(iptuninfo[IFLA_IPTUN_ENCAP_DPORT]);

 		if (iptuninfo[IFLA_IPTUN_COLLECT_METADATA])
 			metadata = 1;

 		if (iptuninfo[IFLA_IPTUN_FWMARK])
 			fwmark = rta_getattr_u32(iptuninfo[IFLA_IPTUN_FWMARK]);

 		free(answer);
 	}

 	while (argc > 0) {
 		if (strcmp(*argv, "mode") == 0) {
 			NEXT_ARG();
 			if (strcmp(lu->id, "sit") == 0 &&
 			    (strcmp(*argv, "ipv6/ipv4") == 0 ||
 			     strcmp(*argv, "ip6ip") == 0))
 				proto = IPPROTO_IPV6;
 			else if (strcmp(*argv, "ipv4/ipv4") == 0 ||
 				 strcmp(*argv, "ipip") == 0 ||
 				 strcmp(*argv, "ip4ip4") == 0)
 				proto = IPPROTO_IPIP;
 			else if (strcmp(*argv, "mpls/ipv4") == 0 ||
 				   strcmp(*argv, "mplsip") == 0)
 				proto = IPPROTO_MPLS;
 			else if (strcmp(*argv, "any/ipv4") == 0 ||
 				 strcmp(*argv, "any") == 0)
 				proto = 0;
 			else
 				invarg("Cannot guess tunnel mode.", *argv);
 		} else if (strcmp(*argv, "remote") == 0) {
 			NEXT_ARG();
 			get_addr(&daddr, *argv, AF_INET);
 		} else if (strcmp(*argv, "local") == 0) {
 			NEXT_ARG();
 			get_addr(&saddr, *argv, AF_INET);
 		} else if (matches(*argv, "dev") == 0) {
 			NEXT_ARG();
 			link = ll_name_to_index(*argv);
 			if (!link)
 				exit(nodev(*argv));
 		} else if (strcmp(*argv, "ttl") == 0 ||
 			   strcmp(*argv, "hoplimit") == 0 ||
 			   strcmp(*argv, "hlim") == 0) {
 			NEXT_ARG();
 			if (strcmp(*argv, "inherit") != 0) {
 				if (get_u8(&ttl, *argv, 0))
 					invarg("invalid TTL\n", *argv);
 			} else
 				ttl = 0;
 		} else if (strcmp(*argv, "tos") == 0 ||
 			   strcmp(*argv, "tclass") == 0 ||
 			   strcmp(*argv, "tc") == 0 ||
 			   matches(*argv, "dsfield") == 0) {
 			__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, "nopmtudisc") == 0) {
 			pmtudisc = 0;
 		} else if (strcmp(*argv, "pmtudisc") == 0) {
 			pmtudisc = 1;
 		} else if (strcmp(lu->id, "sit") == 0 &&
 			   strcmp(*argv, "isatap") == 0) {
 			iflags |= SIT_ISATAP;
 		} 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, "6rd-prefix") == 0) {
 			NEXT_ARG();
 			if (get_prefix(&ip6rdprefix, *argv, AF_INET6))
 				invarg("invalid 6rd_prefix\n", *argv);
 		} else if (strcmp(*argv, "6rd-relay_prefix") == 0) {
 			NEXT_ARG();
 			if (get_prefix(&ip6rdrelayprefix, *argv, AF_INET))
 				invarg("invalid 6rd-relay_prefix\n", *argv);
 		} else if (strcmp(*argv, "6rd-reset") == 0) {
 			get_prefix(&ip6rdprefix, "2002::/16", AF_INET6);
 			inet_prefix_reset(&ip6rdrelayprefix);
 		} else if (strcmp(*argv, "fwmark") == 0) {
 			NEXT_ARG();
 			if (get_u32(&fwmark, *argv, 0))
 				invarg("invalid fwmark\n", *argv);
 		} else {
 			iptunnel_print_help(lu, argc, argv, stderr);
 			return -1;
 		}
 		argc--, argv++;
 	}

 	if (ttl && pmtudisc == 0) {
 		fprintf(stderr, "ttl != 0 and nopmtudisc are incompatible\n");
 		exit(-1);
 	}

 	addattr8(n, 1024, IFLA_IPTUN_PROTO, proto);
 	if (metadata) {
 		addattr_l(n, 1024, IFLA_IPTUN_COLLECT_METADATA, NULL, 0);
 		return 0;
 	}

 	if (is_addrtype_inet_not_unspec(&saddr)) {
 		addattr_l(n, 1024, IFLA_IPTUN_LOCAL,
 			  saddr.data, saddr.bytelen);
 	}
 	if (is_addrtype_inet_not_unspec(&daddr)) {
 		addattr_l(n, 1024, IFLA_IPTUN_REMOTE,
 			  daddr.data, daddr.bytelen);
 	}
 	addattr8(n, 1024, IFLA_IPTUN_PMTUDISC, pmtudisc);
 	addattr8(n, 1024, IFLA_IPTUN_TOS, tos);
 	addattr8(n, 1024, IFLA_IPTUN_TTL, ttl);
 	addattr32(n, 1024, IFLA_IPTUN_LINK, link);
 	addattr32(n, 1024, IFLA_IPTUN_FWMARK, fwmark);

 	addattr16(n, 1024, IFLA_IPTUN_ENCAP_TYPE, encaptype);
 	addattr16(n, 1024, IFLA_IPTUN_ENCAP_FLAGS, encapflags);
 	addattr16(n, 1024, IFLA_IPTUN_ENCAP_SPORT, htons(encapsport));
 	addattr16(n, 1024, IFLA_IPTUN_ENCAP_DPORT, htons(encapdport));

 	if (strcmp(lu->id, "sit") == 0) {
 		addattr16(n, 1024, IFLA_IPTUN_FLAGS, iflags);
 		if (is_addrtype_inet(&ip6rdprefix)) {
 			addattr_l(n, 1024, IFLA_IPTUN_6RD_PREFIX,
 				  ip6rdprefix.data, ip6rdprefix.bytelen);
 			addattr16(n, 1024, IFLA_IPTUN_6RD_PREFIXLEN,
 				  ip6rdprefix.bitlen);
 		}
 		if (is_addrtype_inet(&ip6rdrelayprefix)) {
 			addattr32(n, 1024, IFLA_IPTUN_6RD_RELAY_PREFIX,
 				  ip6rdrelayprefix.data[0]);
 			addattr16(n, 1024, IFLA_IPTUN_6RD_RELAY_PREFIXLEN,
 				  ip6rdrelayprefix.bitlen);
 		}
 	}

 	return 0;
 }

 static void iptunnel_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
 {
 	char s2[64];
 	__u16 prefixlen;
 	__u8 ttl = 0;
 	__u8 tos = 0;

 	if (!tb)
 		return;

 	if (tb[IFLA_IPTUN_COLLECT_METADATA]) {
 		print_bool(PRINT_ANY, "external", "external ", true);
 		return;
 	}

 	if (tb[IFLA_IPTUN_PROTO]) {
 		switch (rta_getattr_u8(tb[IFLA_IPTUN_PROTO])) {
 		case IPPROTO_IPIP:
 			print_string(PRINT_ANY, "proto", "%s ", "ipip");
 			break;
 		case IPPROTO_IPV6:
 			print_string(PRINT_ANY, "proto", "%s ", "ip6ip");
 			break;
 		case IPPROTO_MPLS:
 			print_string(PRINT_ANY, "proto", "%s ", "mplsip");
 			break;
 		case 0:
 			print_string(PRINT_ANY, "proto", "%s ", "any");
 			break;
 		}
 	}

 	tnl_print_endpoint("remote", tb[IFLA_IPTUN_REMOTE], AF_INET);
 	tnl_print_endpoint("local", tb[IFLA_IPTUN_LOCAL], AF_INET);

 	if (tb[IFLA_IPTUN_LINK]) {
 		__u32 link = rta_getattr_u32(tb[IFLA_IPTUN_LINK]);

 		if (link) {
 			print_string(PRINT_ANY, "link", "dev %s ",
 				     ll_index_to_name(link));
 		}
 	}

 	if (tb[IFLA_IPTUN_TTL])
 		ttl = rta_getattr_u8(tb[IFLA_IPTUN_TTL]);
 	if (is_json_context() || ttl)
 		print_uint(PRINT_ANY, "ttl", "ttl %u ", ttl);
 	else
 		print_string(PRINT_FP, NULL, "ttl %s ", "inherit");

 	if (tb[IFLA_IPTUN_TOS])
 		tos = rta_getattr_u8(tb[IFLA_IPTUN_TOS]);
 	if (tos) {
 		if (is_json_context() || tos != 1)
 			print_0xhex(PRINT_ANY, "tos", "tos %#llx ", tos);
 		else
 			print_string(PRINT_FP, NULL, "tos %s ", "inherit");
 	}

 	if (tb[IFLA_IPTUN_PMTUDISC] && rta_getattr_u8(tb[IFLA_IPTUN_PMTUDISC]))
 		print_bool(PRINT_ANY, "pmtudisc", "pmtudisc ", true);
 	else
 		print_bool(PRINT_ANY, "pmtudisc", "nopmtudisc ", false);

 	if (tb[IFLA_IPTUN_FLAGS]) {
 		__u16 iflags = rta_getattr_u16(tb[IFLA_IPTUN_FLAGS]);

 		if (iflags & SIT_ISATAP)
 			print_bool(PRINT_ANY, "isatap", "isatap ", true);
 	}

 	if (tb[IFLA_IPTUN_6RD_PREFIXLEN] &&
 	    (prefixlen = rta_getattr_u16(tb[IFLA_IPTUN_6RD_PREFIXLEN]))) {
 		__u16 relayprefixlen =
 			rta_getattr_u16(tb[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]);
 		__u32 relayprefix =
 			rta_getattr_u32(tb[IFLA_IPTUN_6RD_RELAY_PREFIX]);

 		const char *prefix = inet_ntop(AF_INET6,
 					       RTA_DATA(tb[IFLA_IPTUN_6RD_PREFIX]),
 					       s2, sizeof(s2));

 		if (is_json_context()) {
 			print_string(PRINT_JSON, "prefix", NULL, prefix);
 			print_int(PRINT_JSON, "prefixlen", NULL, prefixlen);
 			if (relayprefix) {
 				print_string(PRINT_JSON,
 					     "relay_prefix",
 					     NULL,
 					     format_host(AF_INET,
 							 4,
 							 &relayprefix));
 				print_int(PRINT_JSON,
 					  "relay_prefixlen",
 					  NULL,
 					  relayprefixlen);
 			}
 		} else {
 			printf("6rd-prefix %s/%u ", prefix, prefixlen);
 			if (relayprefix) {
 				printf("6rd-relay_prefix %s/%u ",
 				       format_host(AF_INET, 4, &relayprefix),
 				       relayprefixlen);
 			}
 		}
 	}

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

 		if (fwmark) {
 			print_0xhex(PRINT_ANY,
 				    "fwmark", "fwmark %#llx ", fwmark);
 		}
 	}

 	tnl_print_encap(tb,
 			IFLA_IPTUN_ENCAP_TYPE,
 			IFLA_IPTUN_ENCAP_FLAGS,
 			IFLA_IPTUN_ENCAP_SPORT,
 			IFLA_IPTUN_ENCAP_DPORT);
 }

 struct link_util ipip_link_util = {
 	.id = "ipip",
 	.maxattr = IFLA_IPTUN_MAX,
 	.parse_opt = iptunnel_parse_opt,
 	.print_opt = iptunnel_print_opt,
 	.print_help = iptunnel_print_help,
 };

 struct link_util sit_link_util = {
 	.id = "sit",
 	.maxattr = IFLA_IPTUN_MAX,
 	.parse_opt = iptunnel_parse_opt,
 	.print_opt = iptunnel_print_opt,
 	.print_help = iptunnel_print_help,
 };
	/*
	* link_iptnl.c ipip and sit 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: Nicolas Dichtel <nicolas.dichtel@6wind.com>
	*
	*/

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

	#include <linux/in.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 iptunnel_print_help(struct link_util lu, int argc, char *argv,
	FILE *f)
	{
	const char *mode;

	if (strcmp(lu->id, "sit") == 0) {
	mode = "{ ip6ip \| ipip \| mplsip \| any } ]\n"
	" [ isatap";
	} else {
	mode = "{ ipip \| mplsip \| any }";
	}

	fprintf(f,
	"Usage: ... %-6s [ remote ADDR ]\n"
	" [ local ADDR ]\n"
	" [ ttl TTL ]\n"
	" [ tos TOS ]\n"
	" [ [no]pmtudisc ]\n"
	" [ 6rd-prefix ADDR ]\n"
	" [ 6rd-relay_prefix ADDR ]\n"
	" [ 6rd-reset ]\n"
	" [ dev PHYS_DEV ]\n"
	" [ fwmark MARK ]\n"
	" [ external ]\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"
	" [ mode %s ]\n"
	"\n"
	"Where: ADDR := { IP_ADDRESS \| any }\n"
	" TOS := { NUMBER \| inherit }\n"
	" TTL := { 1..255 \| inherit }\n"
	" MARK := { 0x0..0xffffffff }\n",
	lu->id, mode);
	}

	static int iptunnel_parse_opt(struct link_util lu, int argc, char *argv,
	struct nlmsghdr *n)
	{
	struct ifinfomsg *ifi = NLMSG_DATA(n);
	struct {
	struct nlmsghdr n;
	struct ifinfomsg i;
	} 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 nlmsghdr *answer;
	struct rtattr *tb[IFLA_MAX + 1];
	struct rtattr *linkinfo[IFLA_INFO_MAX+1];
	struct rtattr *iptuninfo[IFLA_IPTUN_MAX + 1];
	int len;
	inet_prefix saddr, daddr, ip6rdprefix, ip6rdrelayprefix;
	__u8 pmtudisc = 1;
	__u8 tos = 0;
	__u16 iflags = 0;
	__u8 ttl = 0;
	__u8 proto = 0;
	__u32 link = 0;
	__u16 encaptype = 0;
	__u16 encapflags = 0;
	__u16 encapsport = 0;
	__u16 encapdport = 0;
	__u8 metadata = 0;
	__u32 fwmark = 0;

	inet_prefix_reset(&saddr);
	inet_prefix_reset(&daddr);

	inet_prefix_reset(&ip6rdprefix);
	inet_prefix_reset(&ip6rdrelayprefix);

	if (!(n->nlmsg_flags & NLM_F_CREATE)) {
	const struct rtattr *rta;

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

	len = answer->nlmsg_len;
	len -= NLMSG_LENGTH(sizeof(*ifi));
	if (len < 0)
	goto get_failed;

	parse_rtattr(tb, IFLA_MAX, IFLA_RTA(NLMSG_DATA(answer)), 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(iptuninfo, IFLA_IPTUN_MAX,
	linkinfo[IFLA_INFO_DATA]);

	rta = iptuninfo[IFLA_IPTUN_LOCAL];
	if (rta && get_addr_rta(&saddr, rta, AF_INET))
	goto get_failed;

	rta = iptuninfo[IFLA_IPTUN_REMOTE];
	if (rta && get_addr_rta(&daddr, rta, AF_INET))
	goto get_failed;

	rta = iptuninfo[IFLA_IPTUN_6RD_PREFIX];
	if (rta && get_addr_rta(&ip6rdprefix, rta, AF_INET6))
	goto get_failed;

	rta = iptuninfo[IFLA_IPTUN_6RD_RELAY_PREFIX];
	if (rta && get_addr_rta(&ip6rdrelayprefix, rta, AF_INET))
	goto get_failed;

	rta = iptuninfo[IFLA_IPTUN_6RD_PREFIXLEN];
	ip6rdprefix.bitlen = rta ? rta_getattr_u16(rta) : 0;

	rta = iptuninfo[IFLA_IPTUN_6RD_RELAY_PREFIXLEN];
	ip6rdrelayprefix.bitlen = rta ? rta_getattr_u16(rta) : 0;

	if (iptuninfo[IFLA_IPTUN_TTL])
	ttl = rta_getattr_u8(iptuninfo[IFLA_IPTUN_TTL]);

	if (iptuninfo[IFLA_IPTUN_PMTUDISC])
	pmtudisc =
	rta_getattr_u8(iptuninfo[IFLA_IPTUN_PMTUDISC]);

	if (iptuninfo[IFLA_IPTUN_TOS])
	tos = rta_getattr_u8(iptuninfo[IFLA_IPTUN_TOS]);

	if (iptuninfo[IFLA_IPTUN_FLAGS])
	iflags = rta_getattr_u16(iptuninfo[IFLA_IPTUN_FLAGS]);

	if (iptuninfo[IFLA_IPTUN_LINK])
	link = rta_getattr_u32(iptuninfo[IFLA_IPTUN_LINK]);

	if (iptuninfo[IFLA_IPTUN_PROTO])
	proto = rta_getattr_u8(iptuninfo[IFLA_IPTUN_PROTO]);

	if (iptuninfo[IFLA_IPTUN_ENCAP_TYPE])
	encaptype = rta_getattr_u16(iptuninfo[IFLA_IPTUN_ENCAP_TYPE]);
	if (iptuninfo[IFLA_IPTUN_ENCAP_FLAGS])
	encapflags = rta_getattr_u16(iptuninfo[IFLA_IPTUN_ENCAP_FLAGS]);
	if (iptuninfo[IFLA_IPTUN_ENCAP_SPORT])
	encapsport = rta_getattr_u16(iptuninfo[IFLA_IPTUN_ENCAP_SPORT]);
	if (iptuninfo[IFLA_IPTUN_ENCAP_DPORT])
	encapdport = rta_getattr_u16(iptuninfo[IFLA_IPTUN_ENCAP_DPORT]);

	if (iptuninfo[IFLA_IPTUN_COLLECT_METADATA])
	metadata = 1;

	if (iptuninfo[IFLA_IPTUN_FWMARK])
	fwmark = rta_getattr_u32(iptuninfo[IFLA_IPTUN_FWMARK]);

	free(answer);
	}

	while (argc > 0) {
	if (strcmp(*argv, "mode") == 0) {
	NEXT_ARG();
	if (strcmp(lu->id, "sit") == 0 &&
	(strcmp(*argv, "ipv6/ipv4") == 0 \|\|
	strcmp(*argv, "ip6ip") == 0))
	proto = IPPROTO_IPV6;
	else if (strcmp(*argv, "ipv4/ipv4") == 0 \|\|
	strcmp(*argv, "ipip") == 0 \|\|
	strcmp(*argv, "ip4ip4") == 0)
	proto = IPPROTO_IPIP;
	else if (strcmp(*argv, "mpls/ipv4") == 0 \|\|
	strcmp(*argv, "mplsip") == 0)
	proto = IPPROTO_MPLS;
	else if (strcmp(*argv, "any/ipv4") == 0 \|\|
	strcmp(*argv, "any") == 0)
	proto = 0;
	else
	invarg("Cannot guess tunnel mode.", *argv);
	} else if (strcmp(*argv, "remote") == 0) {
	NEXT_ARG();
	get_addr(&daddr, *argv, AF_INET);
	} else if (strcmp(*argv, "local") == 0) {
	NEXT_ARG();
	get_addr(&saddr, *argv, AF_INET);
	} else if (matches(*argv, "dev") == 0) {
	NEXT_ARG();
	link = ll_name_to_index(*argv);
	if (!link)
	exit(nodev(*argv));
	} else if (strcmp(*argv, "ttl") == 0 \|\|
	strcmp(*argv, "hoplimit") == 0 \|\|
	strcmp(*argv, "hlim") == 0) {
	NEXT_ARG();
	if (strcmp(*argv, "inherit") != 0) {
	if (get_u8(&ttl, *argv, 0))
	invarg("invalid TTL\n", *argv);
	} else
	ttl = 0;
	} else if (strcmp(*argv, "tos") == 0 \|\|
	strcmp(*argv, "tclass") == 0 \|\|
	strcmp(*argv, "tc") == 0 \|\|
	matches(*argv, "dsfield") == 0) {
	__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, "nopmtudisc") == 0) {
	pmtudisc = 0;
	} else if (strcmp(*argv, "pmtudisc") == 0) {
	pmtudisc = 1;
	} else if (strcmp(lu->id, "sit") == 0 &&
	strcmp(*argv, "isatap") == 0) {
	iflags \|= SIT_ISATAP;
	} 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, "6rd-prefix") == 0) {
	NEXT_ARG();
	if (get_prefix(&ip6rdprefix, *argv, AF_INET6))
	invarg("invalid 6rd_prefix\n", *argv);
	} else if (strcmp(*argv, "6rd-relay_prefix") == 0) {
	NEXT_ARG();
	if (get_prefix(&ip6rdrelayprefix, *argv, AF_INET))
	invarg("invalid 6rd-relay_prefix\n", *argv);
	} else if (strcmp(*argv, "6rd-reset") == 0) {
	get_prefix(&ip6rdprefix, "2002::/16", AF_INET6);
	inet_prefix_reset(&ip6rdrelayprefix);
	} else if (strcmp(*argv, "fwmark") == 0) {
	NEXT_ARG();
	if (get_u32(&fwmark, *argv, 0))
	invarg("invalid fwmark\n", *argv);
	} else {
	iptunnel_print_help(lu, argc, argv, stderr);
	return -1;
	}
	argc--, argv++;
	}

	if (ttl && pmtudisc == 0) {
	fprintf(stderr, "ttl != 0 and nopmtudisc are incompatible\n");
	exit(-1);
	}

	addattr8(n, 1024, IFLA_IPTUN_PROTO, proto);
	if (metadata) {
	addattr_l(n, 1024, IFLA_IPTUN_COLLECT_METADATA, NULL, 0);
	return 0;
	}

	if (is_addrtype_inet_not_unspec(&saddr)) {
	addattr_l(n, 1024, IFLA_IPTUN_LOCAL,
	saddr.data, saddr.bytelen);
	}
	if (is_addrtype_inet_not_unspec(&daddr)) {
	addattr_l(n, 1024, IFLA_IPTUN_REMOTE,
	daddr.data, daddr.bytelen);
	}
	addattr8(n, 1024, IFLA_IPTUN_PMTUDISC, pmtudisc);
	addattr8(n, 1024, IFLA_IPTUN_TOS, tos);
	addattr8(n, 1024, IFLA_IPTUN_TTL, ttl);
	addattr32(n, 1024, IFLA_IPTUN_LINK, link);
	addattr32(n, 1024, IFLA_IPTUN_FWMARK, fwmark);

	addattr16(n, 1024, IFLA_IPTUN_ENCAP_TYPE, encaptype);
	addattr16(n, 1024, IFLA_IPTUN_ENCAP_FLAGS, encapflags);
	addattr16(n, 1024, IFLA_IPTUN_ENCAP_SPORT, htons(encapsport));
	addattr16(n, 1024, IFLA_IPTUN_ENCAP_DPORT, htons(encapdport));

	if (strcmp(lu->id, "sit") == 0) {
	addattr16(n, 1024, IFLA_IPTUN_FLAGS, iflags);
	if (is_addrtype_inet(&ip6rdprefix)) {
	addattr_l(n, 1024, IFLA_IPTUN_6RD_PREFIX,
	ip6rdprefix.data, ip6rdprefix.bytelen);
	addattr16(n, 1024, IFLA_IPTUN_6RD_PREFIXLEN,
	ip6rdprefix.bitlen);
	}
	if (is_addrtype_inet(&ip6rdrelayprefix)) {
	addattr32(n, 1024, IFLA_IPTUN_6RD_RELAY_PREFIX,
	ip6rdrelayprefix.data[0]);
	addattr16(n, 1024, IFLA_IPTUN_6RD_RELAY_PREFIXLEN,
	ip6rdrelayprefix.bitlen);
	}
	}

	return 0;
	}

	static void iptunnel_print_opt(struct link_util lu, FILE f, struct rtattr *tb[])
	{
	char s2[64];
	__u16 prefixlen;
	__u8 ttl = 0;
	__u8 tos = 0;

	if (!tb)
	return;

	if (tb[IFLA_IPTUN_COLLECT_METADATA]) {
	print_bool(PRINT_ANY, "external", "external ", true);
	return;
	}

	if (tb[IFLA_IPTUN_PROTO]) {
	switch (rta_getattr_u8(tb[IFLA_IPTUN_PROTO])) {
	case IPPROTO_IPIP:
	print_string(PRINT_ANY, "proto", "%s ", "ipip");
	break;
	case IPPROTO_IPV6:
	print_string(PRINT_ANY, "proto", "%s ", "ip6ip");
	break;
	case IPPROTO_MPLS:
	print_string(PRINT_ANY, "proto", "%s ", "mplsip");
	break;
	case 0:
	print_string(PRINT_ANY, "proto", "%s ", "any");
	break;
	}
	}

	tnl_print_endpoint("remote", tb[IFLA_IPTUN_REMOTE], AF_INET);
	tnl_print_endpoint("local", tb[IFLA_IPTUN_LOCAL], AF_INET);

	if (tb[IFLA_IPTUN_LINK]) {
	__u32 link = rta_getattr_u32(tb[IFLA_IPTUN_LINK]);

	if (link) {
	print_string(PRINT_ANY, "link", "dev %s ",
	ll_index_to_name(link));
	}
	}

	if (tb[IFLA_IPTUN_TTL])
	ttl = rta_getattr_u8(tb[IFLA_IPTUN_TTL]);
	if (is_json_context() \|\| ttl)
	print_uint(PRINT_ANY, "ttl", "ttl %u ", ttl);
	else
	print_string(PRINT_FP, NULL, "ttl %s ", "inherit");

	if (tb[IFLA_IPTUN_TOS])
	tos = rta_getattr_u8(tb[IFLA_IPTUN_TOS]);
	if (tos) {
	if (is_json_context() \|\| tos != 1)
	print_0xhex(PRINT_ANY, "tos", "tos %#llx ", tos);
	else
	print_string(PRINT_FP, NULL, "tos %s ", "inherit");
	}

	if (tb[IFLA_IPTUN_PMTUDISC] && rta_getattr_u8(tb[IFLA_IPTUN_PMTUDISC]))
	print_bool(PRINT_ANY, "pmtudisc", "pmtudisc ", true);
	else
	print_bool(PRINT_ANY, "pmtudisc", "nopmtudisc ", false);

	if (tb[IFLA_IPTUN_FLAGS]) {
	__u16 iflags = rta_getattr_u16(tb[IFLA_IPTUN_FLAGS]);

	if (iflags & SIT_ISATAP)
	print_bool(PRINT_ANY, "isatap", "isatap ", true);
	}

	if (tb[IFLA_IPTUN_6RD_PREFIXLEN] &&
	(prefixlen = rta_getattr_u16(tb[IFLA_IPTUN_6RD_PREFIXLEN]))) {
	__u16 relayprefixlen =
	rta_getattr_u16(tb[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]);
	__u32 relayprefix =
	rta_getattr_u32(tb[IFLA_IPTUN_6RD_RELAY_PREFIX]);

	const char *prefix = inet_ntop(AF_INET6,
	RTA_DATA(tb[IFLA_IPTUN_6RD_PREFIX]),
	s2, sizeof(s2));

	if (is_json_context()) {
	print_string(PRINT_JSON, "prefix", NULL, prefix);
	print_int(PRINT_JSON, "prefixlen", NULL, prefixlen);
	if (relayprefix) {
	print_string(PRINT_JSON,
	"relay_prefix",
	NULL,
	format_host(AF_INET,
	4,
	&relayprefix));
	print_int(PRINT_JSON,
	"relay_prefixlen",
	NULL,
	relayprefixlen);
	}
	} else {
	printf("6rd-prefix %s/%u ", prefix, prefixlen);
	if (relayprefix) {
	printf("6rd-relay_prefix %s/%u ",
	format_host(AF_INET, 4, &relayprefix),
	relayprefixlen);
	}
	}
	}

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

	if (fwmark) {
	print_0xhex(PRINT_ANY,
	"fwmark", "fwmark %#llx ", fwmark);
	}
	}

	tnl_print_encap(tb,
	IFLA_IPTUN_ENCAP_TYPE,
	IFLA_IPTUN_ENCAP_FLAGS,
	IFLA_IPTUN_ENCAP_SPORT,
	IFLA_IPTUN_ENCAP_DPORT);
	}

	struct link_util ipip_link_util = {
	.id = "ipip",
	.maxattr = IFLA_IPTUN_MAX,
	.parse_opt = iptunnel_parse_opt,
	.print_opt = iptunnel_print_opt,
	.print_help = iptunnel_print_help,
	};

	struct link_util sit_link_util = {
	.id = "sit",
	.maxattr = IFLA_IPTUN_MAX,
	.parse_opt = iptunnel_parse_opt,
	.print_opt = iptunnel_print_opt,
	.print_help = iptunnel_print_help,
	};