/*	$OpenBSD: rde_lsdb.c,v 1.9 2005/02/09 22:58:08 claudio Exp $ */

/*
 * Copyright (c) 2004, 2005 Claudio Jeker <claudio@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/types.h>
#include <sys/tree.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "ospf.h"
#include "ospfd.h"
#include "rde.h"
#include "log.h"

struct vertex	*vertex_get(struct lsa *, struct rde_nbr *);

int		 lsa_router_check(struct lsa *, u_int16_t);
void		 lsa_age(struct vertex *);
void		 lsa_timeout(int, short, void *);
void		 lsa_refresh(struct vertex *);

struct lsa_tree	*global_lsa_tree;

RB_GENERATE(lsa_tree, vertex, entry, lsa_compare)

void
lsa_init(struct lsa_tree *t)
{
	global_lsa_tree = t;
	RB_INIT(global_lsa_tree);
}

int
lsa_compare(struct vertex *a, struct vertex *b)
{
	if (a->type < b->type)
		return (-1);
	if (a->type > b->type)
		return (1);
	if (a->ls_id < b->ls_id)
		return (-1);
	if (a->ls_id > b->ls_id)
		return (1);
	if (a->adv_rtr < b->adv_rtr)
		return (-1);
	if (a->adv_rtr > b->adv_rtr)
		return (1);
	return (0);
}


struct vertex *
vertex_get(struct lsa *lsa, struct rde_nbr *nbr)
{
	struct vertex	*v;

	if ((v = calloc(1, sizeof(struct vertex))) == NULL)
		fatal(NULL);
	v->nbr = nbr;
	v->lsa = lsa;
	v->changed = v->stamp = time(NULL);
	v->cost = LS_INFINITY;
	v->ls_id = ntohl(lsa->hdr.ls_id);
	v->adv_rtr = ntohl(lsa->hdr.adv_rtr);
	v->type = lsa->hdr.type;
	if (!nbr->self)
		v->flooded = 1; /* XXX fix me */

	evtimer_set(&v->ev, lsa_timeout, v);

	return (v);
}

void
vertex_free(struct vertex *v)
{
	if (v == NULL)
		return;

	evtimer_del(&v->ev);
	free(v->lsa);
	free(v);
}

/* returns -1 if a is older, 1 if newer and 0 if equal to b */
int
lsa_newer(struct lsa_hdr *a, struct lsa_hdr *b)
{
	int32_t		 a32, b32;
	u_int16_t	 a16, b16;
	int		 i;

	if (a == NULL)
		return (-1);
	if (b == NULL)
		return (1);

	/*
	 * The sequnece number is defined as signed 32-bit integer,
	 * no idea how IETF came up with such a stupid idea.
	 */
	a32 = (int32_t)ntohl(a->seq_num);
	b32 = (int32_t)ntohl(b->seq_num);

	if (a32 > b32)
		return (1);
	if (a32 < b32)
		return (-1);

	a16 = ntohs(a->ls_chksum);
	b16 = ntohs(b->ls_chksum);

	if (a16 > b16)
		return (1);
	if (a16 < b16)
		return (-1);

	a16 = ntohs(a->age);
	b16 = ntohs(b->age);

	if (b16 >= MAX_AGE)
		return (-1);
	if (a16 >= MAX_AGE)
		return (1);

	i = b16 - a16;
	if (abs(i) > MAX_AGE_DIFF)
		return (i > 0 ? 1 : -1);

	return (0);
}

int
lsa_check(struct rde_nbr *nbr, struct lsa *lsa, u_int16_t len)
{
	struct area	*area = nbr->area;
	u_int32_t	 metric;

	if (len < sizeof(lsa->hdr)) {
		log_warnx("lsa_check: bad packet size");
		return (0);
	}
	if (ntohs(lsa->hdr.len) != len) {
		log_warnx("lsa_check: bad packet size");
		return (0);
	}

	if (iso_cksum(lsa, len, 0)) {
		log_warnx("lsa_check: bad packet checksum");
		return (0);
	}

	/* invalid ages */
	if ((ntohs(lsa->hdr.age) < 1 && !nbr->self) ||
	    ntohs(lsa->hdr.age) > MAX_AGE) {
		log_warnx("lsa_check: bad age");
		return (0);
	}

	/* invalid sequence number */
	if (ntohl(lsa->hdr.seq_num) == RESV_SEQ_NUM) {
		log_warnx("ls_check: bad seq num");
		return (0);
	}

	switch (lsa->hdr.type) {
	case LSA_TYPE_ROUTER:
		if (!lsa_router_check(lsa, len))
			return (0);
		break;
	case LSA_TYPE_NETWORK:
		if ((len % sizeof(u_int32_t)) ||
		    len < sizeof(lsa->hdr) + sizeof(u_int32_t)) {
			log_warnx("lsa_check: bad LSA network packet");
			return (0);
		}
		break;
	case LSA_TYPE_SUM_NETWORK:
	case LSA_TYPE_SUM_ROUTER:
		if ((len % sizeof(u_int32_t)) ||
		    len < sizeof(lsa->hdr) + sizeof(lsa->data.sum)) {
			log_warnx("lsa_check: bad LSA summary packet");
			return (0);
		}
		metric = ntohl(lsa->data.sum.metric);
		if (metric & ~LSA_METRIC_MASK) {
			log_warnx("lsa_check: bad LSA summary metric");
			return (0);
		}
		break;
	case LSA_TYPE_EXTERNAL:
		if ((len % (3 * sizeof(u_int32_t))) ||
		    len < sizeof(lsa->hdr) + sizeof(lsa->data.asext)) {
			log_warnx("lsa_check: bad LSA as-external packet");
			return (0);
		}
		metric = ntohl(lsa->data.asext.metric);
		if (metric & ~(LSA_METRIC_MASK | LSA_ASEXT_E_FLAG)) {
			log_warnx("lsa_check: bad LSA as-external metric");
			return (0);
		}
		/* AS-external-LSA are silently discarded in stub areas */
		if (area->stub)
			return (0);
		break;
	default:
		log_warnx("lsa_check: unknown type %u", lsa->hdr.type);
		return (0);
	}

	/* MaxAge handling */
	if (lsa->hdr.age == htons(MAX_AGE) && !nbr->self && lsa_find(area,
	    lsa->hdr.type, lsa->hdr.ls_id, lsa->hdr.adv_rtr) == NULL &&
	    !rde_nbr_loading(area)) {
		/*
		 * if no neighbor in state Exchange or Loading
		 * ack LSA but don't add it. Needs to be a direct ack.
		 */
		rde_imsg_compose_ospfe(IMSG_LS_ACK, nbr->peerid, 0, &lsa->hdr,
		    sizeof(struct lsa_hdr));
		return (0);
	}

	return (1);
}

int
lsa_router_check(struct lsa *lsa, u_int16_t len)
{
	struct lsa_rtr_link	*rtr_link;
	char			*buf = (char *)lsa;
	u_int16_t		 i, off, nlinks;

	off = sizeof(lsa->hdr) + sizeof(struct lsa_rtr);
	if (off > len) {
		log_warnx("lsa_check: invalid LSA router packet");
		return (0);
	}

	nlinks = ntohs(lsa->data.rtr.nlinks);
	for (i = 0; i < nlinks; i++) {
		rtr_link = (struct lsa_rtr_link *)(buf + off);
		off += sizeof(struct lsa_rtr_link);
		if (off > len) {
			log_warnx("lsa_check: invalid LSA router packet");
			return (0);
		}
		off += rtr_link->num_tos * sizeof(u_int32_t);
		if (off > len) {
			log_warnx("lsa_check: invalid LSA router packet");
			return (0);
		}
	}

	if (i != nlinks) {
		log_warnx("lsa_check: invalid LSA router packet");
		return (0);
	}
	return (1);
}

int
lsa_self(struct rde_nbr *nbr, struct lsa *new, struct vertex *v)
{
	struct iface	*iface;
	struct lsa	*dummy;

	if (nbr->self)
		return (0);

	if (rde_router_id() == new->hdr.adv_rtr)
		goto self;

	if (new->hdr.type == LSA_TYPE_NETWORK)
		LIST_FOREACH(iface, &nbr->area->iface_list, entry)
		    if (iface->addr.s_addr == new->hdr.ls_id)
			    goto self;

	return (0);

self:
	if (v == NULL) {
		/*
		 * LSA is no longer announced, remove by premature aging.
		 * The problem is that new may not be altered so a copy
		 * needs to be added to the LSA DB first.
		 */
		if ((dummy = malloc(ntohs(new->hdr.len))) == NULL)
			fatal("lsa_self");
		memcpy(dummy, new, ntohs(new->hdr.len));
		dummy->hdr.age = htons(MAX_AGE);
		/*
		 * The clue is that by using the remote nbr as originator
		 * the dummy LSA will be reflooded via the default timeout
		 * handler.
		 */
		lsa_add(rde_nbr_self(nbr->area), dummy);
		return (1);
	}

	/*
	 * LSA is still originated, just reflood it. But we need to create
	 * a new instance by setting the LSA sequence number equal to the
	 * one of new and calling lsa_refresh(). Flooding will be done by the
	 * caller.
	 */
	v->lsa->hdr.seq_num = new->hdr.seq_num;
	lsa_refresh(v);
	return (1);
}

void
lsa_add(struct rde_nbr *nbr, struct lsa *lsa)
{
	struct lsa_tree	*tree;
	struct vertex	*new, *old;
	struct timeval	 tv;

	if (lsa->hdr.type == LSA_TYPE_EXTERNAL)
		tree = global_lsa_tree;
	else
		tree = &nbr->area->lsa_tree;

	new = vertex_get(lsa, nbr);
	old = RB_INSERT(lsa_tree, tree, new);
	if (old != NULL) {
		RB_REMOVE(lsa_tree, tree, old);
		vertex_free(old);
		RB_INSERT(lsa_tree, tree, new);
	}

	/* timeout handling either MAX_AGE or LS_REFRESH_TIME */
	timerclear(&tv);

	if (nbr->self && ntohs(new->lsa->hdr.age) == DEFAULT_AGE)
		tv.tv_sec = LS_REFRESH_TIME;
	else
		tv.tv_sec = MAX_AGE - ntohs(new->lsa->hdr.age);

	if (evtimer_add(&new->ev, &tv) != 0)
		fatal("lsa_add");
}

void
lsa_del(struct rde_nbr *nbr, struct lsa_hdr *lsa)
{
	struct lsa_tree	*tree;
	struct vertex	*v;

	v = lsa_find(nbr->area, lsa->type, lsa->ls_id, lsa->adv_rtr);
	if (v == NULL) {
		log_warnx("lsa_del: LSA no longer in table");
		return;
	}

	if (lsa->type == LSA_TYPE_EXTERNAL)
		tree = global_lsa_tree;
	else
		tree = &nbr->area->lsa_tree;

	RB_REMOVE(lsa_tree, tree, v);
	vertex_free(v);
}

void
lsa_age(struct vertex *v)
{
	time_t		now;
	int		d;
	u_int16_t	age;

	now = time(NULL);
	d = now - v->stamp;
	if (d < 0) {
		log_warnx("lsa_age: time went backwards");
		return;
	}

	age = ntohs(v->lsa->hdr.age);
	if (age + d > MAX_AGE)
		age = MAX_AGE;
	else
		age += d;

	v->lsa->hdr.age = htons(age);
	v->stamp = now;
}

struct vertex *
lsa_find(struct area *area, u_int8_t type, u_int32_t ls_id, u_int32_t adv_rtr)
{
	struct vertex	 key;
	struct vertex	*v;
	struct lsa_tree	*tree;

	key.ls_id = ntohl(ls_id);
	key.adv_rtr = ntohl(adv_rtr);
	key.type = type;

	if (type == LSA_TYPE_EXTERNAL)
		tree = global_lsa_tree;
	else
		tree = &area->lsa_tree;

	v = RB_FIND(lsa_tree, tree, &key);
	if (v)
		lsa_age(v);

	return (v);
}

void
lsa_snap(struct area *area, u_int32_t peerid)
{
	struct lsa_tree	*tree = &area->lsa_tree;
	struct vertex	*v;

	do {
		RB_FOREACH(v, lsa_tree, tree) {
			lsa_age(v);
			if (ntohs(v->lsa->hdr.age) >= MAX_AGE)
				rde_imsg_compose_ospfe(IMSG_LS_UPD, peerid,
				    0, &v->lsa->hdr, ntohs(v->lsa->hdr.len));
			else
				rde_imsg_compose_ospfe(IMSG_DB_SNAPSHOT, peerid,
				    0, &v->lsa->hdr, sizeof(struct lsa_hdr));
		}
		if (tree != &area->lsa_tree)
			break;
		tree = global_lsa_tree;
	} while (1);
}

void
lsa_dump(struct lsa_tree *tree, pid_t pid)
{
	struct vertex	*v;

	RB_FOREACH(v, lsa_tree, tree) {
		lsa_age(v);
		rde_imsg_compose_ospfe(IMSG_CTL_SHOW_DATABASE, 0, pid,
		    &v->lsa->hdr, ntohs(v->lsa->hdr.len));
	}
}

void
lsa_timeout(int fd, short event, void *bula)
{
	struct vertex	*v = bula;

	lsa_age(v);

	log_debug("lsa_timeout: REFLOOD age %d", ntohs(v->lsa->hdr.age));

	if (v->nbr->self && ntohs(v->lsa->hdr.age) < MAX_AGE)
		lsa_refresh(v);

	rde_imsg_compose_ospfe(IMSG_LS_FLOOD, v->nbr->peerid, 0,
	    v->lsa, ntohs(v->lsa->hdr.len));
}

void
lsa_refresh(struct vertex *v)
{
	struct timeval	 tv;
	u_int32_t	 seqnum;
	u_int16_t	 len;

	/* refresh LSA by increasing sequence number by one */
	v->lsa->hdr.age = htons(DEFAULT_AGE);
	seqnum = ntohl(v->lsa->hdr.seq_num);
	if (seqnum++ == MAX_SEQ_NUM)
		/* XXX fix me */
		fatalx("sequence number wrapping");
	v->lsa->hdr.seq_num = htonl(seqnum);

	/* recalculate checksum */
	len = ntohs(v->lsa->hdr.len);
	v->lsa->hdr.ls_chksum = 0;
	v->lsa->hdr.ls_chksum = htons(iso_cksum(v->lsa, len, LS_CKSUM_OFFSET));

	v->changed = v->stamp = time(NULL);
	timerclear(&tv);
	tv.tv_sec = LS_REFRESH_TIME;
	evtimer_add(&v->ev, &tv);
}

void
lsa_merge(struct rde_nbr *nbr, struct lsa *lsa, struct vertex *v)
{
	struct timeval	tv;
	time_t		now;

	if (v == NULL) {
		lsa_add(nbr, lsa);
		rde_imsg_compose_ospfe(IMSG_LS_FLOOD, nbr->peerid, 0,
		    lsa, ntohs(lsa->hdr.len));
		return;
	}

	/* TODO check for changes */

	/* set the seq_num to the current on. lsa_refresh() will do the ++ */
	lsa->hdr.seq_num = v->lsa->hdr.seq_num;
	/* overwrite the lsa all other fields are unaffected */
	free(v->lsa);
	v->lsa = lsa;
	
	/* set correct timeout for reflooding the LSA */
	now = time(NULL);
	timerclear(&tv);
	if (v->changed + MIN_LS_ARRIVAL >= now) 
		tv.tv_sec = MIN_LS_ARRIVAL;
	evtimer_add(&v->ev, &tv);
}