/* $NetBSD: ldp_peer.c,v 1.16.28.1 2023/08/04 13:26:17 martin Exp $ */

/*
 * Copyright (c) 2010 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Mihai Chelaru <kefren@NetBSD.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <netmpls/mpls.h>
#include <arpa/inet.h>

#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <strings.h>
#include <stddef.h>
#include <stdio.h>
#include <unistd.h>

#include "conffile.h"
#include "socketops.h"
#include "ldp_errors.h"
#include "ldp.h"
#include "tlv_stack.h"
#include "mpls_interface.h"
#include "notifications.h"
#include "ldp_peer.h"

extern int ldp_holddown_time;

static struct label_mapping *ldp_peer_get_lm(struct ldp_peer *,
    const struct sockaddr *, uint);

static int mappings_compare(void *, const void *, const void *);
static rb_tree_ops_t mappings_tree_ops = {
	.rbto_compare_nodes = mappings_compare,
	.rbto_compare_key = mappings_compare,
	.rbto_node_offset = offsetof(struct label_mapping, mappings_node),
	.rbto_context = NULL
};

void 
ldp_peer_init(void)
{
	SLIST_INIT(&ldp_peer_head);
}

int
sockaddr_cmp(const struct sockaddr *a, const struct sockaddr *b)
{
	if (a == NULL || b == NULL || a->sa_len != b->sa_len ||
	    a->sa_family != b->sa_family)
		return -1;
	return memcmp(a, b, a->sa_len);
}

static int
mappings_compare(void *context, const void *node1, const void *node2)
{
	const struct label_mapping *l1 = node1, *l2 = node2;
	int ret;

	if (__predict_false(l1->address.sa.sa_family !=
	    l2->address.sa.sa_family))
		return l1->address.sa.sa_family > l2->address.sa.sa_family ?
		    1 : -1;

	assert(l1->address.sa.sa_len == l2->address.sa.sa_len);
	if ((ret = memcmp(&l1->address.sa, &l2->address.sa, l1->address.sa.sa_len)) != 0)
		return ret;

	if (__predict_false(l1->prefix != l2->prefix))
		return l1->prefix > l2->prefix ? 1 : -1;

	return 0;
}

/*
 * soc should be > 1 if there is already a TCP socket for this else we'll
 * initiate a new one
 */
struct ldp_peer *
ldp_peer_new(const struct in_addr * ldp_id, const struct sockaddr * padd,
	     const struct sockaddr * tradd, uint16_t holdtime, int soc)
{
	struct ldp_peer *p;
	int s = soc, sopts;
	union sockunion connecting_su;
	struct conf_neighbour *cn;

	assert(tradd == NULL || tradd->sa_family == padd->sa_family);

	if (soc < 1) {
		s = socket(PF_INET, SOCK_STREAM, 0);
		if (s < 0) {
			fatalp("ldp_peer_new: cannot create socket\n");
			return NULL;
		}
		if (tradd != NULL) {
			assert(tradd->sa_len <= sizeof(connecting_su));
			memcpy(&connecting_su, tradd, tradd->sa_len);
		} else {
			assert(padd->sa_len <= sizeof(connecting_su));
			memcpy(&connecting_su, padd, padd->sa_len);
		}

		assert(connecting_su.sa.sa_family == AF_INET ||
		    connecting_su.sa.sa_family == AF_INET6);

		if (connecting_su.sa.sa_family == AF_INET)
			connecting_su.sin.sin_port = htons(LDP_PORT);
		else
			connecting_su.sin6.sin6_port = htons(LDP_PORT);

		set_ttl(s);
	}

	/* MD5 authentication needed ? */
	SLIST_FOREACH(cn, &conei_head, neilist)
		if (cn->authenticate != 0 &&
		    ldp_id->s_addr == cn->address.s_addr) {
			if (setsockopt(s, IPPROTO_TCP, TCP_MD5SIG, &(int){1},
			    sizeof(int)) != 0)
				fatalp("setsockopt TCP_MD5SIG: %s\n",
				    strerror(errno));
			break;
		}

	/* Set the peer in CONNECTING/CONNECTED state */
	p = calloc(1, sizeof(*p));

	if (!p) {
		fatalp("ldp_peer_new: calloc problem\n");
		return NULL;
	}

	SLIST_INSERT_HEAD(&ldp_peer_head, p, peers);
	p->address = (struct sockaddr *)malloc(padd->sa_len);
	memcpy(p->address, padd, padd->sa_len);
	memcpy(&p->ldp_id, ldp_id, sizeof(struct in_addr));
	if (tradd != NULL) {
		p->transport_address = (struct sockaddr *)malloc(tradd->sa_len);
		memcpy(p->transport_address, tradd, tradd->sa_len);
	} else {
		p->transport_address = (struct sockaddr *)malloc(padd->sa_len);
		memcpy(p->transport_address, padd, padd->sa_len);
	}
	p->holdtime=holdtime > ldp_holddown_time ? holdtime : ldp_holddown_time;
	p->socket = s;
	if (soc < 1) {
		p->state = LDP_PEER_CONNECTING;
		p->master = 1;
	} else {
		p->state = LDP_PEER_CONNECTED;
		p->master = 0;
		set_ttl(p->socket);
	}
	SLIST_INIT(&p->ldp_peer_address_head);
	rb_tree_init(&p->label_mapping_tree, &mappings_tree_ops);
	p->timeout = p->holdtime;

	sopts = fcntl(p->socket, F_GETFL);
	if (sopts >= 0) {
		sopts |= O_NONBLOCK;
		fcntl(p->socket, F_SETFL, &sopts);
	}

	/* And connect to peer */
	if (soc < 1 &&
	    connect(s, &connecting_su.sa, connecting_su.sa.sa_len) == -1) {
		if (errno == EINTR || errno == EINPROGRESS)
			/* We take care of this in big_loop */
			return p;
		warnp("connect to %s failed: %s\n",
		    satos(&connecting_su.sa), strerror(errno));
		ldp_peer_holddown(p);
		return NULL;
	}
	p->state = LDP_PEER_CONNECTED;
	return p;
}

void 
ldp_peer_holddown(struct ldp_peer * p)
{

	if (!p || p->state == LDP_PEER_HOLDDOWN)
		return;
	if (p->state == LDP_PEER_ESTABLISHED) {
		p->state = LDP_PEER_HOLDDOWN;
		mpls_delete_ldp_peer(p);
	} else
		p->state = LDP_PEER_HOLDDOWN;
	p->timeout = p->holdtime;
	shutdown(p->socket, SHUT_RDWR);
	ldp_peer_delete_all_mappings(p);
	del_all_ifaddr(p);
	fatalp("LDP Neighbour %s is DOWN\n", inet_ntoa(p->ldp_id));
}

void
ldp_peer_holddown_all()
{
	struct ldp_peer *p;

	SLIST_FOREACH(p, &ldp_peer_head, peers) {
		if ((p->state == LDP_PEER_ESTABLISHED) ||
		    (p->state == LDP_PEER_CONNECTED))
			send_notification(p, get_message_id(),
			    NOTIF_FATAL | NOTIF_SHUTDOWN);
		ldp_peer_holddown(p);
	}
}

void 
ldp_peer_delete(struct ldp_peer * p)
{

	if (!p)
		return;

	SLIST_REMOVE(&ldp_peer_head, p, ldp_peer, peers);
	close(p->socket);
	warnp("LDP Neighbor %s holddown timer expired\n", inet_ntoa(p->ldp_id));
	free(p->address);
	free(p->transport_address);
	free(p);
}

struct ldp_peer *
get_ldp_peer(const struct sockaddr * a)
{
	struct ldp_peer *p;
	const struct sockaddr_in *a_inet = (const struct sockaddr_in *)a;

	SLIST_FOREACH(p, &ldp_peer_head, peers) {
		if (a->sa_family == AF_INET &&
		    memcmp((const void *) &a_inet->sin_addr,
		      (const void *) &p->ldp_id,
		      sizeof(struct in_addr)) == 0)
			return p;
		if (sockaddr_cmp(a, p->address) == 0 ||
		    sockaddr_cmp(a, p->transport_address) == 0 ||
		    check_ifaddr(p, a))
			return p;
	}
	return NULL;
}

struct ldp_peer *
get_ldp_peer_by_id(const struct in_addr *a)
{
	struct ldp_peer *p;

	SLIST_FOREACH(p, &ldp_peer_head, peers)
		if (memcmp((const void*)a,
		    (const void*)&p->ldp_id, sizeof(*a)) == 0)
			return p;
	return NULL;
}

struct ldp_peer *
get_ldp_peer_by_socket(int s)
{
	struct ldp_peer *p;

	SLIST_FOREACH(p, &ldp_peer_head, peers)
		if (p->socket == s)
			return p;
	return NULL;
}

/*
 * Adds address list bounded to a specific peer
 * Returns the number of addresses inserted successfuly
 */
int 
add_ifaddresses(struct ldp_peer * p, const struct al_tlv * a)
{
	int             i, c, n;
	const char		*ia;
	struct sockaddr_in	ipa;

	memset(&ipa, 0, sizeof(ipa));
	ipa.sin_len = sizeof(ipa);
	ipa.sin_family = AF_INET;
	/*
	 * Check if tlv is Address type, if it's correct size (at least one
	 * address) and if it's IPv4
	 */

	if ((ntohs(a->type) != TLV_ADDRESS_LIST) ||
	    (ntohs(a->length) < sizeof(a->af) + sizeof(struct in_addr)) ||
	    (ntohs(a->af) != LDP_AF_INET))
		return 0;

	/* Number of addresses to insert */
	n = (ntohs(a->length) - sizeof(a->af)) / sizeof(struct in_addr);

	debugp("Trying to add %d addresses to peer %s ... \n", n,
	    inet_ntoa(p->ldp_id));

	for (ia = (const void *)&a->address, c = 0, i = 0; i < n; i++) {
		memcpy(&ipa.sin_addr, ia + i*sizeof(ipa.sin_addr),
		    sizeof(ipa.sin_addr));
		if (add_ifaddr(p, (struct sockaddr *)&ipa) == LDP_E_OK)
			c++;
	}

	debugp("Added %d addresses\n", c);

	return c;
}

int 
del_ifaddresses(struct ldp_peer * p, const struct al_tlv * a)
{
	int             i, c, n;
	const struct in_addr *ia;
	struct sockaddr_in	ipa;

	memset(&ipa, 0, sizeof(ipa));
	ipa.sin_len = sizeof(ipa);
	ipa.sin_family = AF_INET;
	/*
	 * Check if tlv is Address type, if it's correct size (at least one
	 * address) and if it's IPv4
	 */

	if (ntohs(a->type) != TLV_ADDRESS_LIST ||
	    ntohs(a->length) > sizeof(a->af) + sizeof(struct in_addr) ||
	    ntohs(a->af) != LDP_AF_INET)
		return -1;

	n = (ntohs(a->length) - sizeof(a->af)) / sizeof(struct in_addr);

	debugp("Trying to delete %d addresses from peer %s ... \n", n,
	    inet_ntoa(p->ldp_id));

	for (ia = (const struct in_addr *) & a[1], c = 0, i = 0; i < n; i++) {
		memcpy(&ipa.sin_addr, &ia[i], sizeof(ipa.sin_addr));
		if (del_ifaddr(p, (struct sockaddr *)&ipa) == LDP_E_OK)
			c++;
	}

	debugp("Deleted %d addresses\n", c);

	return c;
}


/* Adds a _SINGLE_ INET address to a specific peer */
int 
add_ifaddr(struct ldp_peer * p, const struct sockaddr * a)
{
	struct ldp_peer_address *lpa;

	/* Is it already there ? */
	if (check_ifaddr(p, a))
		return LDP_E_ALREADY_DONE;

	lpa = calloc(1, sizeof(*lpa));

	if (!lpa) {
		fatalp("add_ifaddr: malloc problem\n");
		return LDP_E_MEMORY;
	}

	assert(a->sa_len <= sizeof(union sockunion));

	memcpy(&lpa->address.sa, a, a->sa_len);

	SLIST_INSERT_HEAD(&p->ldp_peer_address_head, lpa, addresses);
	return LDP_E_OK;
}

/* Deletes an address bounded to a specific peer */
int 
del_ifaddr(struct ldp_peer * p, const struct sockaddr * a)
{
	struct ldp_peer_address *wp;

	wp = check_ifaddr(p, a);
	if (!wp)
		return LDP_E_NOENT;

	SLIST_REMOVE(&p->ldp_peer_address_head, wp, ldp_peer_address,
	    addresses);
	free(wp);
	return LDP_E_OK;
}

/* Checks if an address is already bounded */
struct ldp_peer_address *
check_ifaddr(const struct ldp_peer * p, const struct sockaddr * a)
{
	struct ldp_peer_address *wp;

	SLIST_FOREACH(wp, &p->ldp_peer_address_head, addresses)
		if (sockaddr_cmp(a, &wp->address.sa) == 0)
			return wp;
	return NULL;
}

void 
del_all_ifaddr(struct ldp_peer * p)
{
	struct ldp_peer_address *wp;

	while (!SLIST_EMPTY(&p->ldp_peer_address_head)) {
		wp = SLIST_FIRST(&p->ldp_peer_address_head);
		SLIST_REMOVE_HEAD(&p->ldp_peer_address_head, addresses);
		free(wp);
	}
}

void 
print_bounded_addresses(const struct ldp_peer * p)
{
	struct ldp_peer_address *wp;
	char abuf[512];

	snprintf(abuf, sizeof(abuf), "Addresses bounded to peer %s: ",
	    satos(p->address));
	SLIST_FOREACH(wp, &p->ldp_peer_address_head, addresses) {
		strncat(abuf, satos(&wp->address.sa),
			sizeof(abuf) -1);
		strncat(abuf, " ", sizeof(abuf) -1);
	}
	warnp("%s\n", abuf);
}

/* Adds a label and a prefix to a specific peer */
int 
ldp_peer_add_mapping(struct ldp_peer * p, const struct sockaddr * a,
    int prefix, int label)
{
	struct label_mapping *lma;

	if (!p)
		return -1;
	if ((lma = ldp_peer_get_lm(p, a, prefix)) != NULL) {
		/* Change the current label */
		lma->label = label;
		return LDP_E_OK;
	}

	lma = malloc(sizeof(*lma));

	if (!lma) {
		fatalp("ldp_peer_add_mapping: malloc problem\n");
		return LDP_E_MEMORY;
	}

	memcpy(&lma->address, a, a->sa_len);
	lma->prefix = prefix;
	lma->label = label;

	rb_tree_insert_node(&p->label_mapping_tree, lma);

	return LDP_E_OK;
}

int 
ldp_peer_delete_mapping(struct ldp_peer * p, const struct sockaddr * a,
    int prefix)
{
	struct label_mapping *lma;

	if (a == NULL || (lma = ldp_peer_get_lm(p, a, prefix)) == NULL)
		return LDP_E_NOENT;

	rb_tree_remove_node(&p->label_mapping_tree, lma);
	free(lma);

	return LDP_E_OK;
}

static struct label_mapping *
ldp_peer_get_lm(struct ldp_peer * p, const struct sockaddr * a,
    uint prefix)
{
	struct label_mapping rv;

	assert(a->sa_len <= sizeof(union sockunion));

	memset(&rv, 0, sizeof(rv));
	memcpy(&rv.address.sa, a, a->sa_len);
	rv.prefix = prefix;

	return rb_tree_find_node(&p->label_mapping_tree, &rv);
}

void
ldp_peer_delete_all_mappings(struct ldp_peer * p)
{
	struct label_mapping *lma;

	while((lma = RB_TREE_MIN(&p->label_mapping_tree)) != NULL) {
		rb_tree_remove_node(&p->label_mapping_tree, lma);
		free(lma);
	}
}

/* returns a mapping and its peer */
struct peer_map *
ldp_test_mapping(const struct sockaddr * a, int prefix,
    const struct sockaddr * gate)
{
	struct ldp_peer *lpeer;
	struct peer_map *rv = NULL;
	struct label_mapping *lm = NULL;

	/* Checks if it's LPDID, else checks if it's an interface */

	lpeer = get_ldp_peer(gate);
	if (!lpeer) {
		debugp("ldp_test_mapping: Gateway is not an LDP peer\n");
		return NULL;
	}
	if (lpeer->state != LDP_PEER_ESTABLISHED) {
		fatalp("ldp_test_mapping: peer is down ?!\n");
		return NULL;
	}
	lm = ldp_peer_get_lm(lpeer, a, prefix);

	if (!lm) {
		debugp("Cannot match prefix %s/%d to the specified peer\n",
		    satos(a), prefix);
		return NULL;
	}
	rv = malloc(sizeof(*rv));

	if (!rv) {
		fatalp("ldp_test_mapping: malloc problem\n");
		return NULL;
	}

	rv->lm = lm;
	rv->peer = lpeer;

	return rv;
}

struct label_mapping * ldp_peer_lm_right(struct ldp_peer *p,
    struct label_mapping * map)
{
	if (map == NULL)
		return RB_TREE_MIN(&p->label_mapping_tree);
	else
		return rb_tree_iterate(&p->label_mapping_tree, map,
		    RB_DIR_RIGHT);
}

/* Name from state */
const char * ldp_state_to_name(int state)
{
	switch(state) {
		case LDP_PEER_CONNECTING:
			return "CONNECTING";
		case LDP_PEER_CONNECTED:
			return "CONNECTED";
		case LDP_PEER_ESTABLISHED:
			return "ESTABLISHED";
		case LDP_PEER_HOLDDOWN:
			return "HOLDDOWN";
	}
	return "UNKNOWN";
}