/* $USAGI: $ */

/*
 * Copyright (C)2004 USAGI/WIDE Project
 * 
 * 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.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
/*
 * based on iproute.c
 */
/*
 * Authors:
 *	Masahide NAKAMURA @USAGI
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <netdb.h>
#include <linux/netlink.h>
#include <linux/xfrm.h>
#include "utils.h"
#include "xfrm.h"
#include "ip_common.h"

//#define NLMSG_FLUSH_BUF_SIZE (4096-512)
#define NLMSG_FLUSH_BUF_SIZE 8192

/*
 * Receiving buffer defines:
 * nlmsg
 *   data = struct xfrm_userpolicy_info
 *   rtattr
 *     data = struct xfrm_user_tmpl[]
 */
#define NLMSG_BUF_SIZE 4096
#define RTA_BUF_SIZE 2048
#define XFRM_TMPLS_BUF_SIZE 1024

static void usage(void) __attribute__((noreturn));

static void usage(void)
{
	fprintf(stderr, "Usage: ip xfrm policy { add | update } dir DIR sel SELECTOR [ index INDEX ] \n");
	fprintf(stderr, "        [ action ACTION ] [ priority PRIORITY ] [ LIMIT-LIST ] [ TMPL-LIST ]\n");
	fprintf(stderr, "Usage: ip xfrm policy { merge | change | replace } dir DIR\n");
	fprintf(stderr, "        [ sel SELECTOR | index INDEX ] [ TMPL-LIST ]\n");
	fprintf(stderr, "Usage: ip xfrm policy { delete | get } dir DIR [ sel SELECTOR | index INDEX ]\n");
	fprintf(stderr, "Usage: ip xfrm policy { flush | list } [ dir DIR ] [ sel SELECTOR ]\n");
	fprintf(stderr, "        [ index INDEX ] [ action ACTION ] [ priority PRIORITY ]\n");
	fprintf(stderr, "DIR := [ in | out | fwd ]\n");

	fprintf(stderr, "SELECTOR := src ADDR[/PLEN] dst ADDR[/PLEN] [ upspec UPSPEC ] [ dev DEV ]\n");

	fprintf(stderr, "UPSPEC := proto PROTO [ UPSPEC_OPT ]\n");
	fprintf(stderr, "UPSPEC_OPT := [ [ sport PORT ] [ dport PORT ] ] |\n");
#ifdef USE_MIP6
	fprintf(stderr, "              [ type TYPE [ code CODE ] ](for PROTO=ipv6-icmp) |\n");
	fprintf(stderr, "              [ type TYPE ](for PROTO=ipv6-mh)\n");
#else
	fprintf(stderr, "              [ type TYPE [ code CODE ] ](for PROTO=ipv6-icmp)\n");
#endif

	//fprintf(stderr, "DEV - device name(default=none)\n");

	fprintf(stderr, "ACTION := [ allow | block ](default=allow)\n");

	//fprintf(stderr, "PRIORITY - priority value(default=0)\n");

	fprintf(stderr, "LIMIT-LIST := [ LIMIT-LIST ] | [ limit LIMIT ]\n");
	fprintf(stderr, "LIMIT := [ [time-soft|time-hard|time-use-soft|time-use-hard] SECONDS ] |\n");
	fprintf(stderr, "         [ [byte-soft|byte-hard] SIZE ] | [ [packet-soft|packet-hard] NUMBER ]\n");

	fprintf(stderr, "TMPL-LIST := [ TMPL-LIST ] | [ tmpl TMPL ] | [ tmpl remain ](change only)\n");
	fprintf(stderr, "TMPL := ID [ mode MODE ] [ reqid REQID ] [ level LEVEL ]\n");
	fprintf(stderr, "ID := [ src ADDR ] [ dst ADDR ] [ proto XFRM_PROTO ] [ spi SPI ]\n");

#ifdef USE_MIP6
	fprintf(stderr, "XFRM_PROTO := [ esp | ah | ipcomp | route2 | hao ]\n");
#else
	fprintf(stderr, "XFRM_PROTO := [ esp | ah | ipcomp ]\n");
#endif

 	fprintf(stderr, "MODE := [ transport | tunnel ](default=transport)\n");
 	//fprintf(stderr, "REQID - number(default=0)\n");
	fprintf(stderr, "LEVEL := [ required | use ](default=required)\n");

	exit(-1);
}

static int xfrm_policy_dir_parse(__u8 *dir, int *argcp, char ***argvp)
{
	int argc = *argcp;
	char **argv = *argvp;

	if (strcmp(*argv, "in") == 0)
		*dir = XFRM_POLICY_IN;
	else if (strcmp(*argv, "out") == 0)
		*dir = XFRM_POLICY_OUT;
	else if (strcmp(*argv, "fwd") == 0)
		*dir = XFRM_POLICY_FWD;
	else
		invarg("\"DIR\" is invalid", *argv);

	*argcp = argc;
	*argvp = argv;

	return 0;
}

static int xfrm_tmpl_parse(struct xfrm_user_tmpl *tmpl,
			   int *argcp, char ***argvp)
{
	int argc = *argcp;
	char **argv = *argvp;
	char *idp = NULL;

	while (1) {
		if (strcmp(*argv, "mode") == 0) {
			NEXT_ARG();
			xfrm_mode_parse(&tmpl->mode,  &argc, &argv);
		} else if (strcmp(*argv, "reqid") == 0) {
			NEXT_ARG();
			xfrm_reqid_parse(&tmpl->reqid, &argc, &argv);
		} else if (strcmp(*argv, "level") == 0) {
			NEXT_ARG();

			if (strcmp(*argv, "required") == 0)
				tmpl->optional = 0;
			else if (strcmp(*argv, "use") == 0)
				tmpl->optional = 1;
			else
				invarg("\"level\" value is invalid\n", *argv);

		} else {
			if (idp) {
				PREV_ARG(); /* back track */
				break;
			}
			idp = *argv;
			xfrm_id_parse(&tmpl->saddr, &tmpl->id, &tmpl->family,
				      &argc, &argv);
			if (preferred_family == AF_UNSPEC)
				preferred_family = tmpl->family;
		}

		if (!NEXT_ARG_OK())
			break;

		NEXT_ARG();
	}
	if (argc == *argcp)
		missarg("TMPL");

	*argcp = argc;
	*argvp = argv;

	return 0;
}

static int xfrm_policy_modify(int cmd, unsigned flags, int argc, char **argv)
{
	struct rtnl_handle rth;
	struct {
		struct nlmsghdr			n;
		struct xfrm_userpolicy_info	xpinfo;
		char				buf[RTA_BUF_SIZE];
	} req;
	char *dirp = NULL;
	char tmpls_buf[XFRM_TMPLS_BUF_SIZE];
	int tmpls_len = 0;

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

	req.n.nlmsg_len = NLMSG_LENGTH(sizeof(req.xpinfo));
	req.n.nlmsg_flags = NLM_F_REQUEST|flags;
	req.n.nlmsg_type = cmd;
	req.xpinfo.sel.family = preferred_family;

	req.xpinfo.lft.soft_byte_limit = XFRM_INF;
	req.xpinfo.lft.hard_byte_limit = XFRM_INF;
	req.xpinfo.lft.soft_packet_limit = XFRM_INF;
	req.xpinfo.lft.hard_packet_limit = XFRM_INF;

	while (argc > 0) {
		if (strcmp(*argv, "dir") == 0) {
			if (dirp)
				duparg("dir", *argv);
			dirp = *argv;

			NEXT_ARG();
			xfrm_policy_dir_parse(&req.xpinfo.dir, &argc, &argv);

			filter.dir_mask = XFRM_FILTER_MASK_FULL;

		} else if (strcmp(*argv, "sel") == 0) {
			NEXT_ARG();
			xfrm_selector_parse(&req.xpinfo.sel, &argc, &argv);
			if (preferred_family == AF_UNSPEC)
				preferred_family = req.xpinfo.sel.family;

		} else if (strcmp(*argv, "index") == 0) {
			NEXT_ARG();
			if (get_u32(&req.xpinfo.index, *argv, 0))
				invarg("\"INDEX\" is invalid", *argv);

			filter.index_mask = XFRM_FILTER_MASK_FULL;

		} else if (strcmp(*argv, "action") == 0) {
			NEXT_ARG();
			if (strcmp(*argv, "allow") == 0)
				req.xpinfo.action = XFRM_POLICY_ALLOW;
			else if (strcmp(*argv, "block") == 0)
				req.xpinfo.action = XFRM_POLICY_BLOCK;
			else
				invarg("\"action\" value is invalid\n", *argv);

			filter.action_mask = XFRM_FILTER_MASK_FULL;

		} else if (strcmp(*argv, "priority") == 0) {
			NEXT_ARG();
			if (get_u32(&req.xpinfo.priority, *argv, 0))
				invarg("\"PRIORITY\" is invalid", *argv);

			filter.priority_mask = XFRM_FILTER_MASK_FULL;

		} else if (strcmp(*argv, "limit") == 0) {
			NEXT_ARG();
			xfrm_lifetime_cfg_parse(&req.xpinfo.lft, &argc, &argv);
		} else if (strcmp(*argv, "tmpl") == 0) {
			struct xfrm_user_tmpl *tmpl;

			if (tmpls_len + sizeof(*tmpl) > sizeof(tmpls_buf)) {
				fprintf(stderr, "Too many tmpls: buffer overflow\n");
				exit(1);
			}
			tmpl = (struct xfrm_user_tmpl *)((char *)tmpls_buf + tmpls_len);

			tmpl->family = preferred_family;
			tmpl->aalgos = (~(__u32)0);
			tmpl->ealgos = (~(__u32)0);
			tmpl->calgos = (~(__u32)0);

			NEXT_ARG();
			xfrm_tmpl_parse(tmpl, &argc, &argv);

			tmpls_len += sizeof(*tmpl);
		} else
			invarg("unknown", *argv);

		argc--; argv++;
	}

	if (!dirp) {
		fprintf(stderr, "Not enough information: \"DIR\" is required.\n");
		exit(1);
	}

	if (tmpls_len > 0) {
		addattr_l(&req.n, sizeof(req), XFRMA_TMPL,
			  (void *)tmpls_buf, tmpls_len);
	}

	if (rtnl_open_byproto(&rth, 0, NETLINK_XFRM) < 0)
		exit(1);

	if (req.xpinfo.sel.family == AF_UNSPEC)
		req.xpinfo.sel.family = AF_INET;

	if (rtnl_talk(&rth, &req.n, 0, 0, NULL, NULL, NULL) < 0)
		exit(2);

	rtnl_close(&rth);

	return 0;
}

static int xfrm_policy_filter_match(struct xfrm_userpolicy_info *xpinfo)
{
	if (!filter.use)
		return 1;

	if ((xpinfo->dir^filter.xpinfo.dir)&filter.dir_mask)
		return 0;

	if (filter.sel_src_mask) {
		if (memcmp(&xpinfo->sel.saddr, &filter.xpinfo.sel.saddr,
			   filter.sel_src_mask) != 0)
			return 0;
		if (xpinfo->sel.prefixlen_s != filter.xpinfo.sel.prefixlen_s)
			return 0;
	}

	if (filter.sel_dst_mask) {
		if (memcmp(&xpinfo->sel.daddr, &filter.xpinfo.sel.daddr,
			   filter.sel_dst_mask) != 0)
			return 0;
		if (xpinfo->sel.prefixlen_d != filter.xpinfo.sel.prefixlen_d)
			return 0;
	}

	if ((xpinfo->sel.ifindex^filter.xpinfo.sel.ifindex)&filter.sel_dev_mask)
		return 0;

	if ((xpinfo->sel.proto^filter.xpinfo.sel.proto)&filter.upspec_proto_mask)
		return 0;

	if (filter.upspec_sport_mask) {
		if (xpinfo->sel.proto == IPPROTO_ICMPV6)
			return 0;
#ifdef USE_MIP6
		if (xpinfo->sel.proto == IPPROTO_MH)
			return 0;
#endif
		if ((xpinfo->sel.sport^filter.xpinfo.sel.sport)&filter.upspec_sport_mask)
			return 0;
	}

	if (filter.upspec_dport_mask) {
		if (xpinfo->sel.proto == IPPROTO_ICMPV6)
			return 0;
#ifdef USE_MIP6
		if (xpinfo->sel.proto == IPPROTO_MH)
			return 0;
#endif
		if ((xpinfo->sel.dport^filter.xpinfo.sel.dport)&filter.upspec_dport_mask)
			return 0;
	}

	if (filter.upspec_type_mask) {
		if (xpinfo->sel.proto == IPPROTO_ICMPV6) {
			if ((xpinfo->sel.xfrmsel_icmp_type^filter.xpinfo.sel.xfrmsel_icmp_type)&filter.xpinfo.sel.xfrmsel_icmp_type_mask)
				return 0;
#ifdef USE_MIP6
		} else if (xpinfo->sel.proto == IPPROTO_MH) {
			if ((xpinfo->sel.xfrmsel_mh_type^filter.xpinfo.sel.xfrmsel_mh_type)&filter.xpinfo.sel.xfrmsel_mh_type_mask)
				return 0;
#endif
		} else
			return 0;
	}

	if (filter.upspec_code_mask) {
		if (xpinfo->sel.proto == IPPROTO_ICMPV6) {
			if ((xpinfo->sel.xfrmsel_icmp_code^filter.xpinfo.sel.xfrmsel_icmp_code)&filter.upspec_code_mask)
				return 0;
		} else
			return 0;
	}

	if ((xpinfo->index^filter.xpinfo.index)&filter.index_mask)
		return 0;

	if ((xpinfo->action^filter.xpinfo.action)&filter.action_mask)
		return 0;

	if ((xpinfo->priority^filter.xpinfo.priority)&filter.priority_mask)
		return 0;

	return 1;
}

int xfrm_policy_print(struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)
{
	FILE *fp = (FILE*)arg;
	struct xfrm_userpolicy_info *xpinfo = NLMSG_DATA(n);
	int len = n->nlmsg_len;
	struct rtattr * tb[XFRM_MAX_DEPTH];
	int ntb;

	if (n->nlmsg_type != XFRM_MSG_NEWPOLICY &&
	    n->nlmsg_type != XFRM_MSG_DELPOLICY) {
		fprintf(stderr, "Not a policy: %08x %08x %08x\n",
			n->nlmsg_len, n->nlmsg_type, n->nlmsg_flags);
		return 0;
	}

	len -= NLMSG_LENGTH(sizeof(*xpinfo));
	if (len < 0) {
		fprintf(stderr, "BUG: wrong nlmsg len %d\n", len);
		return -1;
	}

	if (!xfrm_policy_filter_match(xpinfo))
		return 0;

	memset(tb, 0, sizeof(tb));
	ntb = parse_rtattr_byindex(tb, XFRM_MAX_DEPTH, XFRMP_RTA(xpinfo), len);

	if (n->nlmsg_type == XFRM_MSG_DELPOLICY)
		fprintf(fp, "Deleted ");

	xfrm_selector_print(&xpinfo->sel, preferred_family, fp, NULL);

	fprintf(fp, "\t");
	fprintf(fp, "%s ", (xpinfo->dir == XFRM_POLICY_IN ? "in " :
			    xpinfo->dir == XFRM_POLICY_OUT ? "out" :
			    xpinfo->dir == XFRM_POLICY_FWD ? "fwd" :
			    "unknown-dir"));
	fprintf(fp, "%s ", (xpinfo->action == XFRM_POLICY_ALLOW ? "allow" :
			   xpinfo->action == XFRM_POLICY_BLOCK ? "block" :
			   "unknown-action"));
	fprintf(fp, "index %u ", xpinfo->index);
	fprintf(fp, "priority %u ", xpinfo->priority);
	fprintf(fp, "share %s ", strxf_share(xpinfo->share));
	fprintf(fp, "flags 0x%s", strxf_flags(xpinfo->flags));
	fprintf(fp, "\n");

	if (show_stats > 0)
		xfrm_lifetime_print(&xpinfo->lft, &xpinfo->curlft, fp, "\t");

	xfrm_xfrma_print(tb, ntb, xpinfo->sel.family, fp, "\t");

	return 0;
}

static int xfrm_policy_get_or_delete(int argc, char **argv, int delete,
				     void *res_nlbuf)
{
	struct rtnl_handle rth;
	struct {
		struct nlmsghdr			n;
		struct xfrm_userpolicy_id	xpid;
	} req;
	char *dirp = NULL;
	char *selp = NULL;
	char *indexp = NULL;

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

	req.n.nlmsg_len = NLMSG_LENGTH(sizeof(req.xpid));
	req.n.nlmsg_flags = NLM_F_REQUEST;
	req.n.nlmsg_type = delete ? XFRM_MSG_DELPOLICY : XFRM_MSG_GETPOLICY;

	while (argc > 0) {
		if (strcmp(*argv, "dir") == 0) {
			if (dirp)
				duparg("dir", *argv);
			dirp = *argv;

			NEXT_ARG();
			xfrm_policy_dir_parse(&req.xpid.dir, &argc, &argv);

		} else if (strcmp(*argv, "sel") == 0) {
			if (selp)
				duparg("sel", *argv);
			selp = *argv;

			NEXT_ARG();
			xfrm_selector_parse(&req.xpid.sel, &argc, &argv);
			if (preferred_family == AF_UNSPEC)
				preferred_family = req.xpid.sel.family;

		} else if (strcmp(*argv, "index") == 0) {
			if (indexp)
				duparg("index", *argv);
			indexp = *argv;

			NEXT_ARG();
			if (get_u32(&req.xpid.index, *argv, 0))
				invarg("\"INDEX\" is invalid", *argv);

		} else
			invarg("unknown", *argv);

		argc--; argv++;
	}

	if (!dirp) {
		fprintf(stderr, "Not enough information: \"DIR\" is required.\n");
		exit(1);
	}
	if (!selp && !indexp) {
		fprintf(stderr, "Not enough information: either \"SELECTOR\" or \"INDEX\" is required.\n");
		exit(1);
	}
	if (selp && indexp)
		duparg2("SELECTOR", "INDEX");

	if (rtnl_open_byproto(&rth, 0, NETLINK_XFRM) < 0)
		exit(1);

	if (req.xpid.sel.family == AF_UNSPEC)
		req.xpid.sel.family = AF_INET;

	if (rtnl_talk(&rth, &req.n, 0, 0, res_nlbuf, NULL, NULL) < 0)
		exit(2);

	rtnl_close(&rth);

	return 0;
}

/*
 * Smaller scored tmpl should be first for a policy.
 * Score=0 means unknown protocol or one which can't be judged.
 */
static int xfrm_id_proto_score(__u8 proto, __u8 dir)
{
	/*
	 * Basically, score is reversed order as extensions headers
	 *
	 *     <- large                     small ->
	 * [IP][..][RT2][HAO][..][AH][ESP][COMP][..]
	 *
	 * Exception:
	 * At outbound case, any protocols should be followed AH.
	 */
	switch (proto) {
	case IPPROTO_ESP:
		return (1 << 3);
	case IPPROTO_AH:
		if (dir == XFRM_POLICY_IN)
			return (1 << 4);
		else
			return (1 << 12);
	case IPPROTO_COMP:
		return (1 << 2);
#ifdef USE_MIP6
	case IPPROTO_ROUTING: /* assuming RT2 */
		return (1 << 7);
	case IPPROTO_DSTOPTS: /* assuming HAO */
		return (1 << 6);
#endif
	default:
		break;
	}

	return 0;
}

/*
 * Compare templates t1 and t2 and return less than, equal to, or greater
 * than zero if t1 is found respectively, to be before, to be the same,
 * or to be after than t2 for its "preferred" order for a policy
 * in using under IPsec and/or MIPv6.
 */
static int xfrm_tmpl_preferred_cmp(struct xfrm_user_tmpl *t1,
				   struct xfrm_user_tmpl *t2,
				   __u8 dir)
{
	int score1;
	int score2;

	score1 = xfrm_id_proto_score(t1->id.proto, dir);
	if (score1 == 0) {
		/* assume t1 as lower score */
		return -1;
	}

	score2 = xfrm_id_proto_score(t2->id.proto, dir);

	return (score1 - score2);
}

static int xfrm_tmpl_extract(struct rtattr *tb[], int ntb,
			     struct xfrm_user_tmpl *tmpls, int *ntmpls)
{
	int idx = 0;
	__u16 type;
	int n;
	struct xfrm_user_tmpl *t;
	int i;
	int j;

	/* store existing templates */
	for (i = 0; i < ntb; i++) {
		type = tb[i]->rta_type;
		if (type != XFRMA_TMPL) {
			fprintf(stderr, "Policy has attr which is not template: %u\n", type);
			exit(1);
		}

		n = tb[i]->rta_len / sizeof(struct xfrm_user_tmpl);
		t = (struct xfrm_user_tmpl *)RTA_DATA(tb[i]);

		for (j = 0; j < n; j++) {
			memcpy(&tmpls[idx], &t[j], sizeof(tmpls[idx]));
			idx ++;
		}
	}

	*ntmpls = idx;
	return 0;
}

/*
 * (existing tmpl=ET, new tmpls=NT)
 * Any ET keeps sequence within ETs (ET never changes order within ETs).
 * It is also NT's case. With those rules, tmpls are merged by preferred order.
 */
static int xfrm_tmpl_merge(struct xfrm_user_tmpl *tcur, int n_tcur,
			   struct xfrm_user_tmpl *tnew, int n_tnew,
			   __u8 dir, struct nlmsghdr *n, int len)
{
	struct tmpl_list {
		struct tmpl_list *next;
		struct xfrm_user_tmpl *tmplp;
	};
	struct tmpl_list *head = NULL;
	struct tmpl_list *prev;
	struct tmpl_list *p;
	struct xfrm_user_tmpl tmpls[XFRM_MAX_DEPTH];
	int ntmpls;
	int i;

	if (n_tcur + n_tnew > XFRM_MAX_DEPTH) {
		fprintf(stderr, "Too many tmpls when merging: exists=%u + new=%u makes overflow\n", n_tcur, n_tnew);
		exit(1);
	}

	fprintf(stderr, "DEBUG: %s: dir = %s\n", __FUNCTION__,
		(dir == XFRM_POLICY_IN ? "in " :
		 dir == XFRM_POLICY_OUT ? "out" :
		 dir == XFRM_POLICY_FWD ? "fwd" :
		 "unknown-dir"));

	/* store existing templates to list */
	prev = NULL;
	for (i = 0; i < n_tcur; i++) {
		struct tmpl_list *tl;

		tl = malloc(sizeof(struct tmpl_list));
		if (!tl) {
			perror("malloc");
			exit(1);
		}
		tl->next = NULL;
		tl->tmplp = &tcur[i];

		fprintf(stderr, "DEBUG: kernel tmpl %d = %u\n",i+1,tl->tmplp->id.proto);

		if (!prev)
			head = tl;
		else
			prev->next = tl;
		prev = tl;
	}

#if 1
	for (i = 0; i < n_tnew; i++)
		fprintf(stderr, "DEBUG: new tmpl %d = %u\n",i+1,tnew[i].id.proto);
#endif

	/* order them; compare and insert new one to list */
	i = 0;
	prev = NULL;
	for (p = head; p; p = p->next) {
		int cmp = xfrm_tmpl_preferred_cmp(p->tmplp, &tnew[i], dir);
		if (cmp > 0) {
			struct tmpl_list *tl;

			tl = malloc(sizeof(struct tmpl_list));
			if (!tl) {
				perror("malloc");
				exit(1);
			}
			tl->tmplp = &tnew[i];
			tl->next = p;

			if (p == head)
				head = tl;
			if (prev)
				prev->next = tl;
			p = tl;

			i ++;
		}
		prev = p;

		if (i >= n_tnew)
			break;
	}
	if (!p) {
		/* append rest of new tmpls to the end of list */
		p = prev;
		for (; i < n_tnew; i++) {
			struct tmpl_list *tl;

			tl = malloc(sizeof(struct tmpl_list));
			if (!tl) {
				perror("malloc");
				exit(1);
			}
			tl->tmplp = &tnew[i];
			tl->next = NULL;

			if (!p) /* no kernel tmpls case */
				head = tl;
			else
				p->next = tl;
			p = tl;
		}
	}

	/* store ordered list to buffer */
	memset(&tmpls, 0, sizeof(tmpls));
	i = 0;
	for (p = head; p; p = p->next) {
		if (i >= sizeof(tmpls) / sizeof(tmpls[0])) {
			fprintf(stderr, "Too many tmpls: buffer overflow\n");
			exit(1);
		}

		memcpy(&tmpls[i], p->tmplp, sizeof(tmpls[i]));

		fprintf(stderr, "DEBUG: merged tmpl %d = %u\n", i+1, p->tmplp->id.proto);

		i ++;
	}
	ntmpls = i;

	prev = NULL;
	for (p = head; p; p = p->next) {
		if (prev)
			free(prev);
		prev = p;
	}
	if (prev)
		free(prev);

	addattr_l(n, len, XFRMA_TMPL, (void *)tmpls,
		  (sizeof(struct xfrm_user_tmpl) * ntmpls));

	return 0;
}

/*
 * (existing tmpl=ET, new tmpls=NT)
 * Updates ET by specified NT at each order without "remain" NT.
 */
static int xfrm_tmpl_change(struct xfrm_user_tmpl *tcur, int n_tcur,
			    struct xfrm_user_tmpl *tnew, int n_tnew,
			    __u8 dir, struct nlmsghdr *n, int len)
{
	struct xfrm_user_tmpl tmpls[XFRM_MAX_DEPTH];
	int ntmpls;
	int n_changed = 0;
	int i;

	if (n_tcur != n_tnew) {
		fprintf(stderr, "Templates count differs: %d != %d\n",
			n_tcur, n_tnew);
		exit(1);
	}
	if (n_tcur >= sizeof(tmpls) / sizeof(tmpls[0])) {
		fprintf(stderr, "Too many tmpls: buffer overflow\n");
		exit(1);
	}

	fprintf(stderr, "DEBUG: %s: dir = %s\n", __FUNCTION__,
		(dir == XFRM_POLICY_IN ? "in " :
		 dir == XFRM_POLICY_OUT ? "out" :
		 dir == XFRM_POLICY_FWD ? "fwd" :
		 "unknown-dir"));

	/* change it to new one except remain request */
	for (i = 0; i < n_tcur; i++) {
		struct xfrm_user_tmpl *t;

		if (tnew[i].id.proto == 0) /* remain case */
			t = &tcur[i];
		else {
			t = &tnew[i];
			n_changed ++;
		}

		memcpy(&tmpls[i], t, sizeof(tmpls[i]));
	}
	ntmpls = n_tcur;

	if (n_changed == 0) {
		fprintf(stderr, "No template to be changed is found.\n");
		exit(1);
	}
	fprintf(stderr, "DEBUG: changed tmpls = %d\n", n_changed);

	addattr_l(n, len, XFRMA_TMPL, (void *)tmpls,
		  (sizeof(struct xfrm_user_tmpl) * ntmpls));

	return 0;
}

/*
 * (existing tmpl=ET, new tmpls=NT)
 * Updates the first ET whose protocol is matched with NT once.
 */
static int xfrm_tmpl_replace(struct xfrm_user_tmpl *tcur, int n_tcur,
			    struct xfrm_user_tmpl *tnew, int n_tnew,
			    __u8 dir, struct nlmsghdr *n, int len)
{
	struct xfrm_user_tmpl tmpls[XFRM_MAX_DEPTH];
	int ntmpls;
	int n_replaced = 0;
	int i;
	int j;

	if (n_tcur < n_tnew) {
		fprintf(stderr, "Too many tmpls: %d < %d: replace request should be less than current\n", n_tcur, n_tnew);
		exit(1);
	}
	if (n_tcur >= sizeof(tmpls) / sizeof(tmpls[0])) {
		fprintf(stderr, "Too many tmpls: buffer overflow\n");
		exit(1);
	}

	/* check if duplcate protocol is found */
	for (i = 0; i < n_tnew; i++) {
		for (j = i + 1; j < n_tnew; j++) {
			if (tnew[j].id.proto == tnew[i].id.proto) {
				fprintf(stderr, "Duplicate protocol specified by replacing request\n");
				exit(1);
			}
		}
	}

	/* at first, just store existing tmpls to buffer */
	for (i = 0; i < n_tcur; i++)
		memcpy(&tmpls[i], &tcur[i], sizeof(tmpls[i]));
	ntmpls = n_tcur;

	/* compare and change it to new one */
	for (i = 0; i < n_tnew; i++) {

		if (tnew[i].id.proto == 0) /* remain case */
			continue;

		for (j = 0; j < ntmpls; j++) {
			if (tmpls[j].id.proto == tnew[i].id.proto) {
				memcpy(&tmpls[j], &tnew[i], sizeof(tmpls[j]));
				n_replaced ++;
				break;
			}
		}
	}

	if (n_replaced == 0) {
		fprintf(stderr, "No template to be replaced is found.\n");
		exit(1);
	}
	fprintf(stderr, "DEBUG: %s: dir = %s\n", __FUNCTION__,
		(dir == XFRM_POLICY_IN ? "in " :
		 dir == XFRM_POLICY_OUT ? "out" :
		 dir == XFRM_POLICY_FWD ? "fwd" :
		 "unknown-dir"));
	fprintf(stderr, "DEBUG: replaced tmpls = %d\n", n_replaced);

	addattr_l(n, len, XFRMA_TMPL, (void *)tmpls,
		  (sizeof(struct xfrm_user_tmpl) * ntmpls));

	return 0;
}

/*
 * To modify templates, get existing policy and then update it.
 *
 * "modify":
 *   0 : To merge both exsiting template and new one.
 *   1 : To change existing template by which new one at each order.
 *   2 : To replace existing template whose protocol is matched by new one.
 *       Each replacing occurs once.
 */
static int xfrm_policy_tmpl_modify(int cmd, unsigned flags,
				   int argc, char **argv, int modify)
{
	struct rtnl_handle rth;
	struct {
		struct nlmsghdr			n;
		struct xfrm_userpolicy_id	xpid;
	} req;
	char *dirp = NULL;
	char *selp = NULL;
	char *indexp = NULL;
	int len;
	struct rtattr * tb[XFRMA_MAX+1];
	int ntb;
	char res_buf[NLMSG_BUF_SIZE];
	struct nlmsghdr *res_n;
	struct xfrm_userpolicy_info *res_xpinfo;
	struct xfrm_user_tmpl tmpls_cur[XFRM_MAX_DEPTH];
	int ntmpls_cur = 0;
	struct xfrm_user_tmpl tmpls_new[XFRM_MAX_DEPTH];
	int ntmpls_new = 0;
	struct {
		struct nlmsghdr			n;
		struct xfrm_userpolicy_info	xpinfo;
		char				buf[RTA_BUF_SIZE];
	} req_upd;

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

	req.n.nlmsg_len = NLMSG_LENGTH(sizeof(req.xpid));
	req.n.nlmsg_flags = NLM_F_REQUEST;
	req.n.nlmsg_type = XFRM_MSG_GETPOLICY;

	while (argc > 0) {
		if (strcmp(*argv, "dir") == 0) {
			if (dirp)
				duparg("dir", *argv);
			dirp = *argv;

			NEXT_ARG();
			xfrm_policy_dir_parse(&req.xpid.dir, &argc, &argv);

		} else if (strcmp(*argv, "sel") == 0) {
			if (selp)
				duparg("sel", *argv);
			selp = *argv;

			NEXT_ARG();
			xfrm_selector_parse(&req.xpid.sel, &argc, &argv);
			if (preferred_family == AF_UNSPEC)
				preferred_family = req.xpid.sel.family;

		} else if (strcmp(*argv, "index") == 0) {
			if (indexp)
				duparg("index", *argv);
			indexp = *argv;

			NEXT_ARG();
			if (get_u32(&req.xpid.index, *argv, 0))
				invarg("\"INDEX\" is invalid", *argv);

		} else if (strcmp(*argv, "tmpl") == 0) {
			struct xfrm_user_tmpl *tmpl;

			if (ntmpls_new >= sizeof(tmpls_new) / sizeof(struct xfrm_user_tmpl)) {
				fprintf(stderr, "Too many tmpls: buffer overflow: %d\n", ntmpls_new);
				exit(1);
			}
			tmpl = &tmpls_new[ntmpls_new];
			ntmpls_new ++;

			memset(tmpl, 0, sizeof(*tmpl));
			tmpl->family = preferred_family;
			tmpl->aalgos = (~(__u32)0);
			tmpl->ealgos = (~(__u32)0);
			tmpl->calgos = (~(__u32)0);

			NEXT_ARG();

			if (strcmp(*argv, "remain") == 0) {
				if (modify == 0)
					invarg("invalid with merge command", *argv);
				/*
				 * do nothing;
				 * id.proto = 0 will be assumed remain one
				 * after here.
				 */
			} else
				xfrm_tmpl_parse(tmpl, &argc, &argv);

		} else
				invarg("unknown", *argv);

		argc--; argv++;
	}

	if (!dirp) {
		fprintf(stderr, "Not enough information: \"DIR\" is required.\n");
		exit(1);
	}
	if (!selp && !indexp) {
		fprintf(stderr, "Not enough information: either \"SELECTOR\" or \"INDEX\" is required.\n");
		exit(1);
	}

	if (rtnl_open_byproto(&rth, 0, NETLINK_XFRM) < 0)
		exit(1);

	if (req.xpid.sel.family == AF_UNSPEC)
		req.xpid.sel.family = AF_INET;

	memset(res_buf, 0, sizeof(res_buf));
	res_n = (struct nlmsghdr *)res_buf;

	/* try to get an existing policy */
	if (rtnl_talk(&rth, &req.n, 0, 0, res_n, NULL, NULL) < 0)
		exit(2);

	res_xpinfo = (struct xfrm_userpolicy_info *)NLMSG_DATA(res_n);
	len = res_n->nlmsg_len - NLMSG_LENGTH(sizeof(*res_xpinfo));
	if (len < 0) {
		fprintf(stderr, "BUG: wrong nlmsg len %d\n", len);
		return -1;
	}

	memset(tb, 0, sizeof(tb));
	ntb = parse_rtattr_byindex(tb, XFRM_MAX_DEPTH, XFRMP_RTA(res_xpinfo), len);

	ntmpls_cur = 0;
	xfrm_tmpl_extract(tb, ntb, tmpls_cur, &ntmpls_cur);

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

	req_upd.n.nlmsg_len = NLMSG_LENGTH(sizeof(req_upd.xpinfo));
	req_upd.n.nlmsg_flags = NLM_F_REQUEST|flags;
	req_upd.n.nlmsg_type = XFRM_MSG_UPDPOLICY;

	memcpy(&req_upd.xpinfo, res_xpinfo, sizeof(req_upd.xpinfo));

	switch (modify) {
	case 0:
		/* merging templates */
		xfrm_tmpl_merge(tmpls_cur, ntmpls_cur, tmpls_new, ntmpls_new,
				req.xpid.dir, &req_upd.n, sizeof(req_upd));
		break;
	case 1:
		/* changing templates */
		xfrm_tmpl_change(tmpls_cur, ntmpls_cur, tmpls_new, ntmpls_new,
				 req.xpid.dir, &req_upd.n, sizeof(req_upd));
		break;
	case 2:
		/* replacing templates */
		xfrm_tmpl_replace(tmpls_cur, ntmpls_cur, tmpls_new, ntmpls_new,
				  req.xpid.dir, &req_upd.n, sizeof(req_upd));
		break;
	default:
		/* not reached */
		fprintf(stderr, "Internal error\n");
		exit(1);
	}

	if (req_upd.xpinfo.sel.family == AF_UNSPEC)
		req_upd.xpinfo.sel.family = AF_INET;

	/* update with new poilcy */
	if (rtnl_talk(&rth, &req_upd.n, 0, 0, NULL, NULL, NULL) < 0)
		exit(2);

	rtnl_close(&rth);

	return 0;
}

static int xfrm_policy_delete(int argc, char **argv)
{
	return xfrm_policy_get_or_delete(argc, argv, 1, NULL);
}

static int xfrm_policy_get(int argc, char **argv)
{
	char buf[NLMSG_BUF_SIZE];
	struct nlmsghdr *n = (struct nlmsghdr *)buf;

	memset(buf, 0, sizeof(buf));

	xfrm_policy_get_or_delete(argc, argv, 0, n);

	if (xfrm_policy_print(NULL, n, (void*)stdout) < 0) {
		fprintf(stderr, "An error :-)\n");
		exit(1);
	}

	return 0;
}

/*
 * With an existing policy of nlmsg, make new nlmsg for deleting the policy
 * and store it to buffer.
 */
int xfrm_policy_keep(struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)
{
	struct xfrm_buffer *xb = (struct xfrm_buffer *)arg;
	struct rtnl_handle *rth = xb->rth;
	struct xfrm_userpolicy_info *xpinfo = NLMSG_DATA(n);
	int len = n->nlmsg_len;
	struct nlmsghdr *new_n;
	struct xfrm_userpolicy_id *xpid;

	if (n->nlmsg_type != XFRM_MSG_NEWPOLICY) {
		fprintf(stderr, "Not a policy: %08x %08x %08x\n",
			n->nlmsg_len, n->nlmsg_type, n->nlmsg_flags);
		return 0;
	}

	len -= NLMSG_LENGTH(sizeof(*xpinfo));
	if (len < 0) {
		fprintf(stderr, "BUG: wrong nlmsg len %d\n", len);
		return -1;
	}

	if (!xfrm_policy_filter_match(xpinfo))
		return 0;

	if (xb->offset > xb->size) {
		fprintf(stderr, "Flush buffer overflow\n");
		return -1;
	}

	new_n = (struct nlmsghdr *)(xb->buf + xb->offset);
	new_n->nlmsg_len = NLMSG_LENGTH(sizeof(*xpid));
	new_n->nlmsg_flags = NLM_F_REQUEST;
	new_n->nlmsg_type = XFRM_MSG_DELPOLICY;
	new_n->nlmsg_seq = ++rth->seq;

	xpid = NLMSG_DATA(new_n);
	memcpy(&xpid->sel, &xpinfo->sel, sizeof(xpid->sel));
	xpid->dir = xpinfo->dir;
	xpid->index = xpinfo->index;

	xb->offset += new_n->nlmsg_len;
	xb->nlmsg_count ++;

	return 0;
}

static int xfrm_policy_list_or_flush(int argc, char **argv, int flush)
{
	struct rtnl_handle rth;

	if (argc > 0)
		filter.use = 1;
	filter.xpinfo.sel.family = preferred_family;

	while (argc > 0) {
		if (strcmp(*argv, "dir") == 0) {
			NEXT_ARG();
			xfrm_policy_dir_parse(&filter.xpinfo.dir, &argc, &argv);

			filter.dir_mask = XFRM_FILTER_MASK_FULL;

		} else if (strcmp(*argv, "sel") == 0) {
			NEXT_ARG();
			xfrm_selector_parse(&filter.xpinfo.sel, &argc, &argv);
			if (preferred_family == AF_UNSPEC)
				preferred_family = filter.xpinfo.sel.family;

		} else if (strcmp(*argv, "index") == 0) {
			NEXT_ARG();
			if (get_u32(&filter.xpinfo.index, *argv, 0))
				invarg("\"INDEX\" is invalid", *argv);

			filter.index_mask = XFRM_FILTER_MASK_FULL;

		} else if (strcmp(*argv, "action") == 0) {
			NEXT_ARG();
			if (strcmp(*argv, "allow") == 0)
				filter.xpinfo.action = XFRM_POLICY_ALLOW;
			else if (strcmp(*argv, "block") == 0)
				filter.xpinfo.action = XFRM_POLICY_BLOCK;
			else
				invarg("\"action\" value is invalid\n", *argv);

			filter.action_mask = XFRM_FILTER_MASK_FULL;

		} else if (strcmp(*argv, "priority") == 0) {
			NEXT_ARG();
			if (get_u32(&filter.xpinfo.priority, *argv, 0))
				invarg("\"PRIORITY\" is invalid", *argv);

			filter.priority_mask = XFRM_FILTER_MASK_FULL;

		} else
			invarg("unknown", *argv);

		argc--; argv++;
	}

	if (rtnl_open_byproto(&rth, 0, NETLINK_XFRM) < 0)
		exit(1);

	if (flush) {
		struct xfrm_buffer xb;
		char buf[NLMSG_FLUSH_BUF_SIZE];
		int i;

		xb.buf = buf;
		xb.size = sizeof(buf);
		xb.rth = &rth;

		for (i = 0; ; i++) {
			xb.offset = 0;
			xb.nlmsg_count = 0;

			if (show_stats > 1)
				fprintf(stderr, "Flush round = %d\n", i);

			if (rtnl_wilddump_request(&rth, preferred_family, XFRM_MSG_GETPOLICY) < 0) {
				perror("Cannot send dump request");
				exit(1);
			}

			if (rtnl_dump_filter(&rth, xfrm_policy_keep, &xb, NULL, NULL) < 0) {
				fprintf(stderr, "Flush terminated\n");
				exit(1);
			}
			if (xb.nlmsg_count == 0) {
				if (show_stats > 1)
					fprintf(stderr, "Flush completed\n");
				break;
			}

			if (rtnl_send(&rth, xb.buf, xb.offset) < 0) {
				perror("Failed to send flush request\n");
				exit(1);
			}
			if (show_stats > 1)
				fprintf(stderr, "Flushed nlmsg count = %d\n", xb.nlmsg_count);

			xb.offset = 0;
			xb.nlmsg_count = 0;
		}
	} else {
		if (rtnl_wilddump_request(&rth, preferred_family, XFRM_MSG_GETPOLICY) < 0) {
			perror("Cannot send dump request");
			exit(1);
		}

		if (rtnl_dump_filter(&rth, xfrm_policy_print, stdout, NULL, NULL) < 0) {
			fprintf(stderr, "Dump terminated\n");
			exit(1);
		}
	}

	rtnl_close(&rth);

	exit(0);
}

int do_xfrm_policy(int argc, char **argv)
{
	if (argc < 1)
		return xfrm_policy_list_or_flush(0, NULL, 0);

#if 0
	/*
	 * NLM_F_X is not supported for xfrm in the kernel.
	 */
	if (matches(*argv, "add") == 0)
		return xfrm_policy_modify(XFRM_MSG_NEWPOLICY, NLM_F_CREATE|NLM_F_EXCL,
					  argc-1, argv+1);
	if (matches(*argv, "change") == 0 || strcmp(*argv, "chg") == 0)
		return xfrm_policy_modify(XFRM_MSG_NEWPOLICY, NLM_F_REPLACE,
					  argc-1, argv+1);
	if (matches(*argv, "replace") == 0)
		return xfrm_policy_modify(XFRM_MSG_NEWPOLICY, NLM_F_CREATE|NLM_F_REPLACE,
					  argc-1, argv+1);
	if (matches(*argv, "prepend") == 0)
		return xfrm_policy_modify(XFRM_MSG_NEWPOLICY, NLM_F_CREATE,
					  argc-1, argv+1);
	if (matches(*argv, "append") == 0)
		return xfrm_policy_modify(XFRM_MSG_NEWPOLICY, NLM_F_CREATE|NLM_F_APPEND,
					  argc-1, argv+1);
	if (matches(*argv, "test") == 0)
		return xfrm_policy_modify(XFRM_MSG_NEWPOLICY, NLM_F_EXCL,
					  argc-1, argv+1);
#endif
	if (matches(*argv, "add") == 0)
		return xfrm_policy_modify(XFRM_MSG_NEWPOLICY, 0,
					  argc-1, argv+1);
	if (matches(*argv, "update") == 0)
		return xfrm_policy_modify(XFRM_MSG_UPDPOLICY, 0,
					  argc-1, argv+1);
	if (matches(*argv, "merge") == 0)
		return xfrm_policy_tmpl_modify(XFRM_MSG_UPDPOLICY, 0,
					       argc-1, argv+1, 0);
	if (matches(*argv, "change") == 0)
		return xfrm_policy_tmpl_modify(XFRM_MSG_UPDPOLICY, 0,
					       argc-1, argv+1, 1);
	if (matches(*argv, "replace") == 0)
		return xfrm_policy_tmpl_modify(XFRM_MSG_UPDPOLICY, 0,
					       argc-1, argv+1, 2);
	if (matches(*argv, "delete") == 0 || matches(*argv, "del") == 0)
		return xfrm_policy_delete(argc-1, argv+1);
	if (matches(*argv, "list") == 0 || matches(*argv, "show") == 0
	    || matches(*argv, "lst") == 0)
		return xfrm_policy_list_or_flush(argc-1, argv+1, 0);
	if (matches(*argv, "get") == 0)
		return xfrm_policy_get(argc-1, argv+1);
	if (matches(*argv, "flush") == 0)
		return xfrm_policy_list_or_flush(argc-1, argv+1, 1);
	if (matches(*argv, "help") == 0)
		usage();
	fprintf(stderr, "Command \"%s\" is unknown, try \"ip xfrm policy help\".\n", *argv);
	exit(-1);
}