/*

 * iptunnel.c	       "ip tunnel"

 *

 *		This program is free software; you can redistribute it and/or

 *		modify it under the terms of the GNU General Public License

 *		as published by the Free Software Foundation; either version

 *		2 of the License, or (at your option) any later version.

 *

 * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>

 *

 */

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include <sys/types.h>

#include <sys/socket.h>

#include <arpa/inet.h>

#include <sys/ioctl.h>

#include <net/if.h>

#include <net/if_arp.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 usage(void) __attribute__((noreturn));

static void usage(void)

{

	fprintf(stderr,

		"Usage: ip tunnel { add | change | del | show | prl | 6rd } [ NAME ]\n"

		"	 [ mode { ipip | gre | sit | isatap | vti } ] [ remote ADDR ] [ local ADDR ]\n"

		"	 [ [i|o]seq ] [ [i|o]key KEY ] [ [i|o]csum ]\n"

		"	 [ prl-default ADDR ] [ prl-nodefault ADDR ] [ prl-delete ADDR ]\n"

		"	 [ 6rd-prefix ADDR ] [ 6rd-relay_prefix ADDR ] [ 6rd-reset ]\n"

		"	 [ ttl TTL ] [ tos TOS ] [ [no]pmtudisc ] [ dev PHYS_DEV ]\n"

		"\n"

		"Where:	NAME := STRING\n"

		"	ADDR := { IP_ADDRESS | any }\n"

		"	TOS  := { STRING | 00..ff | inherit | inherit/STRING | inherit/00..ff }\n"

		"	TTL  := { 1..255 | inherit }\n"

		"	KEY  := { DOTTED_QUAD | NUMBER }\n");

	exit(-1);

}

static void set_tunnel_proto(struct ip_tunnel_parm *p, int proto)

{

	if (p->iph.protocol && p->iph.protocol != proto) {

		fprintf(stderr,

			"You managed to ask for more than one tunnel mode.\n");

		exit(-1);

	}

	p->iph.protocol = proto;

}

static int parse_args(int argc, char **argv, int cmd, struct ip_tunnel_parm *p)

{

	int count = 0;

	const char *medium = NULL;

	int isatap = 0;

	memset(p, 0, sizeof(*p));

	p->iph.version = 4;

	p->iph.ihl = 5;

#ifndef IP_DF

#define IP_DF		0x4000		/* Flag: "Don't Fragment"	*/

#endif

	p->iph.frag_off = htons(IP_DF);

	while (argc > 0) {

		if (strcmp(*argv, "mode") == 0) {

			NEXT_ARG();

			if (strcmp(*argv, "ipip") == 0 ||

			    strcmp(*argv, "ip/ip") == 0) {

				set_tunnel_proto(p, IPPROTO_IPIP);

			} else if (strcmp(*argv, "gre") == 0 ||

				   strcmp(*argv, "gre/ip") == 0) {

				set_tunnel_proto(p, IPPROTO_GRE);

			} else if (strcmp(*argv, "sit") == 0 ||

				   strcmp(*argv, "ipv6/ip") == 0) {

				set_tunnel_proto(p, IPPROTO_IPV6);

			} else if (strcmp(*argv, "isatap") == 0) {

				set_tunnel_proto(p, IPPROTO_IPV6);

				isatap++;

			} else if (strcmp(*argv, "vti") == 0) {

				set_tunnel_proto(p, IPPROTO_IPIP);

				p->i_flags |= VTI_ISVTI;

			} else {

				fprintf(stderr,

					"Unknown tunnel mode \"%s\"\n", *argv);

				exit(-1);

			}

		} else if (strcmp(*argv, "key") == 0) {

			NEXT_ARG();

			p->i_flags |= GRE_KEY;

			p->o_flags |= GRE_KEY;

			p->i_key = p->o_key = tnl_parse_key("key", *argv);

		} else if (strcmp(*argv, "ikey") == 0) {

			NEXT_ARG();

			p->i_flags |= GRE_KEY;

			p->i_key = tnl_parse_key("ikey", *argv);

		} else if (strcmp(*argv, "okey") == 0) {

			NEXT_ARG();

			p->o_flags |= GRE_KEY;

			p->o_key = tnl_parse_key("okey", *argv);

		} else if (strcmp(*argv, "seq") == 0) {

			p->i_flags |= GRE_SEQ;

			p->o_flags |= GRE_SEQ;

		} else if (strcmp(*argv, "iseq") == 0) {

			p->i_flags |= GRE_SEQ;

		} else if (strcmp(*argv, "oseq") == 0) {

			p->o_flags |= GRE_SEQ;

		} else if (strcmp(*argv, "csum") == 0) {

			p->i_flags |= GRE_CSUM;

			p->o_flags |= GRE_CSUM;

		} else if (strcmp(*argv, "icsum") == 0) {

			p->i_flags |= GRE_CSUM;

		} else if (strcmp(*argv, "ocsum") == 0) {

			p->o_flags |= GRE_CSUM;

		} else if (strcmp(*argv, "nopmtudisc") == 0) {

			p->iph.frag_off = 0;

		} else if (strcmp(*argv, "pmtudisc") == 0) {

			p->iph.frag_off = htons(IP_DF);

		} else if (strcmp(*argv, "remote") == 0) {

			NEXT_ARG();

			p->iph.daddr = get_addr32(*argv);

		} else if (strcmp(*argv, "local") == 0) {

			NEXT_ARG();

			p->iph.saddr = get_addr32(*argv);

		} else if (strcmp(*argv, "dev") == 0) {

			NEXT_ARG();

			medium = *argv;

		} else if (strcmp(*argv, "ttl") == 0 ||

			   strcmp(*argv, "hoplimit") == 0 ||

			   strcmp(*argv, "hlim") == 0) {

			__u8 uval;

			NEXT_ARG();

			if (strcmp(*argv, "inherit") != 0) {

				if (get_u8(&uval, *argv, 0))

					invarg("invalid TTL\n", *argv);

				p->iph.ttl = uval;

			}

		} else if (strcmp(*argv, "tos") == 0 ||

			   strcmp(*argv, "tclass") == 0 ||

			   matches(*argv, "dsfield") == 0) {

			char *dsfield;

			__u32 uval;

			NEXT_ARG();

			dsfield = *argv;

			strsep(&dsfield, "/");

			if (strcmp(*argv, "inherit") != 0) {

				dsfield = *argv;

				p->iph.tos = 0;

			} else

				p->iph.tos = 1;

			if (dsfield) {

				if (rtnl_dsfield_a2n(&uval, dsfield))

					invarg("bad TOS value", *argv);

				p->iph.tos |= uval;

			}

		} else {

			if (strcmp(*argv, "name") == 0)

				NEXT_ARG();

			else if (matches(*argv, "help") == 0)

				usage();

			if (p->name[0])

				duparg2("name", *argv);

			if (get_ifname(p->name, *argv))

				invarg("\"name\" not a valid ifname", *argv);

			if (cmd == SIOCCHGTUNNEL && count == 0) {

				struct ip_tunnel_parm old_p = {};

				if (tnl_get_ioctl(*argv, &old_p))

					return -1;

				*p = old_p;

			}

		}

		count++;

		argc--; argv++;

	}

	if (p->iph.protocol == 0) {

		if (memcmp(p->name, "gre", 3) == 0)

			p->iph.protocol = IPPROTO_GRE;

		else if (memcmp(p->name, "ipip", 4) == 0)

			p->iph.protocol = IPPROTO_IPIP;

		else if (memcmp(p->name, "sit", 3) == 0)

			p->iph.protocol = IPPROTO_IPV6;

		else if (memcmp(p->name, "isatap", 6) == 0) {

			p->iph.protocol = IPPROTO_IPV6;

			isatap++;

		} else if (memcmp(p->name, "vti", 3) == 0) {

			p->iph.protocol = IPPROTO_IPIP;

			p->i_flags |= VTI_ISVTI;

		}

	}

	if ((p->i_flags & GRE_KEY) || (p->o_flags & GRE_KEY)) {

		if (!(p->i_flags & VTI_ISVTI) &&

		    (p->iph.protocol != IPPROTO_GRE)) {

			fprintf(stderr, "Keys are not allowed with ipip and sit tunnels\n");

			return -1;

		}

	}

	if (medium) {

		p->link = ll_name_to_index(medium);

		if (!p->link)

			return nodev(medium);

	}

	if (p->i_key == 0 && IN_MULTICAST(ntohl(p->iph.daddr))) {

		p->i_key = p->iph.daddr;

		p->i_flags |= GRE_KEY;

	}

	if (p->o_key == 0 && IN_MULTICAST(ntohl(p->iph.daddr))) {

		p->o_key = p->iph.daddr;

		p->o_flags |= GRE_KEY;

	}

	if (IN_MULTICAST(ntohl(p->iph.daddr)) && !p->iph.saddr) {

		fprintf(stderr, "A broadcast tunnel requires a source address\n");

		return -1;

	}

	if (isatap)

		p->i_flags |= SIT_ISATAP;

	return 0;

}

static const char *tnl_defname(const struct ip_tunnel_parm *p)

{

	switch (p->iph.protocol) {

	case IPPROTO_IPIP:

		if (p->i_flags & VTI_ISVTI)

			return "ip_vti0";

		else

			return "tunl0";

	case IPPROTO_GRE:

		return "gre0";

	case IPPROTO_IPV6:

		return "sit0";

	}

	return NULL;

}

static int do_add(int cmd, int argc, char **argv)

{

	struct ip_tunnel_parm p;

	const char *basedev;

	if (parse_args(argc, argv, cmd, &p) < 0)

		return -1;

	if (p.iph.ttl && p.iph.frag_off == 0) {

		fprintf(stderr, "ttl != 0 and nopmtudisc are incompatible\n");

		return -1;

	}

	basedev = tnl_defname(&p);

	if (!basedev) {

		fprintf(stderr,

			"cannot determine tunnel mode (ipip, gre, vti or sit)\n");

		return -1;

	}

	return tnl_add_ioctl(cmd, basedev, p.name, &p);

}

static int do_del(int argc, char **argv)

{

	struct ip_tunnel_parm p;

	if (parse_args(argc, argv, SIOCDELTUNNEL, &p) < 0)

		return -1;

	return tnl_del_ioctl(tnl_defname(&p) ? : p.name, p.name, &p);

}

static void print_tunnel(const void *t)

{

	const struct ip_tunnel_parm *p = t;

	struct ip_tunnel_6rd ip6rd = {};

	SPRINT_BUF(b1);

	/* Do not use format_host() for local addr,

	 * symbolic name will not be useful.

	 */

	open_json_object(NULL);

	print_color_string(PRINT_ANY, COLOR_IFNAME, "ifname", "%s: ", p->name);

	snprintf(b1, sizeof(b1), "%s/ip", tnl_strproto(p->iph.protocol));

	print_string(PRINT_ANY, "mode", "%s ", b1);

	print_null(PRINT_FP, NULL, "remote ", NULL);

	print_color_string(PRINT_ANY, COLOR_INET, "remote", "%s ",

			   p->iph.daddr || is_json_context()

				? format_host_r(AF_INET, 4, &p->iph.daddr, b1, sizeof(b1))

				: "any");

	print_null(PRINT_FP, NULL, "local ", NULL);

	print_color_string(PRINT_ANY, COLOR_INET, "local", "%s",

			   p->iph.saddr || is_json_context()

				? rt_addr_n2a_r(AF_INET, 4, &p->iph.saddr, b1, sizeof(b1))

				: "any");

	if (p->iph.protocol == IPPROTO_IPV6 && (p->i_flags & SIT_ISATAP)) {

		struct ip_tunnel_prl prl[16] = {};

		int i;

		prl[0].datalen = sizeof(prl) - sizeof(prl[0]);

		prl[0].addr = htonl(INADDR_ANY);

		if (!tnl_prl_ioctl(SIOCGETPRL, p->name, prl)) {

			for (i = 1; i < ARRAY_SIZE(prl); i++) {

				if (prl[i].addr == htonl(INADDR_ANY))

					continue;

				if (prl[i].flags & PRL_DEFAULT)

					print_string(PRINT_ANY, "pdr",

						     " pdr %s",

						     format_host(AF_INET, 4, &prl[i].addr));

				else

					print_string(PRINT_ANY, "pr", " pr %s",

						     format_host(AF_INET, 4, &prl[i].addr));

			}

		}

	}

	if (p->link) {

		const char *n = ll_index_to_name(p->link);

		if (n)

			print_string(PRINT_ANY, "dev", " dev %s", n);

	}

	if (p->iph.ttl)

		print_uint(PRINT_ANY, "ttl", " ttl %u", p->iph.ttl);

	else

		print_string(PRINT_FP, "ttl", " ttl %s", "inherit");

	if (p->iph.tos) {

		SPRINT_BUF(b2);

		if (p->iph.tos != 1) {

			if (!is_json_context() && p->iph.tos & 1)

				snprintf(b2, sizeof(b2), "%s%s",

					 p->iph.tos & 1 ? "inherit/" : "",

					 rtnl_dsfield_n2a(p->iph.tos & ~1, b1, sizeof(b1)));

			else

				snprintf(b2, sizeof(b2), "%s",

					 rtnl_dsfield_n2a(p->iph.tos, b1, sizeof(b1)));

			print_string(PRINT_ANY, "tos", " tos %s", b2);

		} else {

			print_string(PRINT_FP, NULL, " tos %s", "inherit");

		}

	}

	if (!(p->iph.frag_off & htons(IP_DF)))

		print_null(PRINT_ANY, "nopmtudisc", " nopmtudisc", NULL);

	if (p->iph.protocol == IPPROTO_IPV6 && !tnl_ioctl_get_6rd(p->name, &ip6rd) && ip6rd.prefixlen) {

		print_string(PRINT_ANY, "6rd-prefix", " 6rd-prefix %s",

			     inet_ntop(AF_INET6, &ip6rd.prefix, b1, sizeof(b1)));

		print_uint(PRINT_ANY, "6rd-prefixlen", "/%u", ip6rd.prefixlen);

		if (ip6rd.relay_prefix) {

			print_string(PRINT_ANY, "6rd-relay_prefix",

				     " 6rd-relay_prefix %s",

				     format_host(AF_INET, 4, &ip6rd.relay_prefix));

			print_uint(PRINT_ANY, "6rd-relay_prefixlen", "/%u",

				   ip6rd.relay_prefixlen);

		}

	}

	tnl_print_gre_flags(p->iph.protocol, p->i_flags, p->o_flags,

			    p->i_key, p->o_key);

	close_json_object();

}

static void ip_tunnel_parm_initialize(const struct tnl_print_nlmsg_info *info)

{

	struct ip_tunnel_parm *p2 = info->p2;

	memset(p2, 0, sizeof(*p2));

}

static bool ip_tunnel_parm_match(const struct tnl_print_nlmsg_info *info)

{

	const struct ip_tunnel_parm *p1 = info->p1;

	const struct ip_tunnel_parm *p2 = info->p2;

	return ((!p1->link || p1->link == p2->link) &&

		(!p1->name[0] || strcmp(p1->name, p2->name) == 0) &&

		(!p1->iph.daddr || p1->iph.daddr == p2->iph.daddr) &&

		(!p1->iph.saddr || p1->iph.saddr == p2->iph.saddr) &&

		(!p1->i_key || p1->i_key == p2->i_key));

}

static int do_show(int argc, char **argv)

{

	struct ip_tunnel_parm p, p1;

	const char *basedev;

	if (parse_args(argc, argv, SIOCGETTUNNEL, &p) < 0)

		return -1;

	basedev = tnl_defname(&p);

	if (!basedev) {

		struct tnl_print_nlmsg_info info = {

			.p1    = &p,

			.p2    = &p1,

			.init  = ip_tunnel_parm_initialize,

			.match = ip_tunnel_parm_match,

			.print = print_tunnel,

		};

		return do_tunnels_list(&info;;

	}

	if (tnl_get_ioctl(p.name[0] ? p.name : basedev, &p))

		return -1;

	print_tunnel(&p);

	fputc('\n', stdout);

	return 0;

}

static int do_prl(int argc, char **argv)

{

	struct ip_tunnel_prl p = {};

	int count = 0;

	int cmd = 0;

	const char *medium = NULL;

	while (argc > 0) {

		if (strcmp(*argv, "prl-default") == 0) {

			NEXT_ARG();

			cmd = SIOCADDPRL;

			p.addr = get_addr32(*argv);

			p.flags |= PRL_DEFAULT;

			count++;

		} else if (strcmp(*argv, "prl-nodefault") == 0) {

			NEXT_ARG();

			cmd = SIOCADDPRL;

			p.addr = get_addr32(*argv);

			count++;

		} else if (strcmp(*argv, "prl-delete") == 0) {

			NEXT_ARG();

			cmd = SIOCDELPRL;

			p.addr = get_addr32(*argv);

			count++;

		} else if (strcmp(*argv, "dev") == 0) {

			NEXT_ARG();

			if (check_ifname(*argv))

				invarg("\"dev\" not a valid ifname", *argv);

			medium = *argv;

		} else {

			fprintf(stderr,

				"Invalid PRL parameter \"%s\"\n", *argv);

			exit(-1);

		}

		if (count > 1) {

			fprintf(stderr,

				"One PRL entry at a time\n");

			exit(-1);

		}

		argc--; argv++;

	}

	if (!medium) {

		fprintf(stderr, "Must specify device\n");

		exit(-1);

	}

	return tnl_prl_ioctl(cmd, medium, &p);

}

static int do_6rd(int argc, char **argv)

{

	struct ip_tunnel_6rd ip6rd = {};

	int cmd = 0;

	const char *medium = NULL;

	inet_prefix prefix;

	while (argc > 0) {

		if (strcmp(*argv, "6rd-prefix") == 0) {

			NEXT_ARG();

			if (get_prefix(&prefix, *argv, AF_INET6))

				invarg("invalid 6rd_prefix\n", *argv);

			cmd = SIOCADD6RD;

			memcpy(&ip6rd.prefix, prefix.data, 16);

			ip6rd.prefixlen = prefix.bitlen;

		} else if (strcmp(*argv, "6rd-relay_prefix") == 0) {

			NEXT_ARG();

			if (get_prefix(&prefix, *argv, AF_INET))

				invarg("invalid 6rd-relay_prefix\n", *argv);

			cmd = SIOCADD6RD;

			memcpy(&ip6rd.relay_prefix, prefix.data, 4);

			ip6rd.relay_prefixlen = prefix.bitlen;

		} else if (strcmp(*argv, "6rd-reset") == 0) {

			cmd = SIOCDEL6RD;

		} else if (strcmp(*argv, "dev") == 0) {

			NEXT_ARG();

			if (check_ifname(*argv))

				invarg("\"dev\" not a valid ifname", *argv);

			medium = *argv;

		} else {

			fprintf(stderr,

				"Invalid 6RD parameter \"%s\"\n", *argv);

			exit(-1);

		}

		argc--; argv++;

	}

	if (!medium) {

		fprintf(stderr, "Must specify device\n");

		exit(-1);

	}

	return tnl_6rd_ioctl(cmd, medium, &ip6rd);

}

static int tunnel_mode_is_ipv6(char *tunnel_mode)

{

	static const char * const ipv6_modes[] = {

		"ipv6/ipv6", "ip6ip6",

		"vti6",

		"ip/ipv6", "ipv4/ipv6", "ipip6", "ip4ip6",

		"ip6gre", "gre/ipv6",

		"any/ipv6", "any"

	};

	int i;

	for (i = 0; i < ARRAY_SIZE(ipv6_modes); i++) {

		if (strcmp(ipv6_modes[i], tunnel_mode) == 0)

			return 1;

	}

	return 0;

}

int do_iptunnel(int argc, char **argv)

{

	int i;

	for (i = 0; i < argc - 1; i++) {

		if (strcmp(argv[i], "mode") == 0) {

			if (tunnel_mode_is_ipv6(argv[i + 1]))

				preferred_family = AF_INET6;

			break;

		}

	}

	switch (preferred_family) {

	case AF_UNSPEC:

		preferred_family = AF_INET;

		break;

	case AF_INET:

		break;

	/*

	 * This is silly enough but we have no easy way to make it

	 * protocol-independent because of unarranged structure between

	 * IPv4 and IPv6.

	 */

	case AF_INET6:

		return do_ip6tunnel(argc, argv);

	default:

		fprintf(stderr, "Unsupported protocol family: %d\n", preferred_family);

		exit(-1);

	}

	if (argc > 0) {

		if (matches(*argv, "add") == 0)

			return do_add(SIOCADDTUNNEL, argc - 1, argv + 1);

		if (matches(*argv, "change") == 0)

			return do_add(SIOCCHGTUNNEL, argc - 1, argv + 1);

		if (matches(*argv, "delete") == 0)

			return do_del(argc - 1, argv + 1);

		if (matches(*argv, "show") == 0 ||

		    matches(*argv, "lst") == 0 ||

		    matches(*argv, "list") == 0)

			return do_show(argc - 1, argv + 1);

		if (matches(*argv, "prl") == 0)

			return do_prl(argc - 1, argv + 1);

		if (matches(*argv, "6rd") == 0)

			return do_6rd(argc - 1, argv + 1);

		if (matches(*argv, "help") == 0)

			usage();

	} else

		return do_show(0, NULL);

	fprintf(stderr, "Command \"%s\" is unknown, try \"ip tunnel help\"\n", *argv);

	exit(-1);

}