/*
  Copyright (c) 2013-2014, Matthias Schiffer <mschiffer@universe-factory.net>
  All rights reserved.

  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 COPYRIGHT HOLDERS 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 COPYRIGHT HOLDER 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 "babel.h"
#include "neigh.h"
#include "packet.h"
#include "tlv.h"
#include "tlv_types.h"

#include <assert.h>


static inline bool send_neigh(gmrf_context_t *ctx, const gp_babel_neigh_t *neigh, const gp_babel_packet_t *packet) {
	if (!neigh->iface)
		return false;

	if (!gmrf_iface_send(ctx->gmrf, neigh->iface->gmrf_iface, packet, gp_babel_packet_size(packet), &neigh->addr)) {
		gmrf_logf(ctx->gmrf, LOG_WARNING, "gmrf_iface_send: %m");
		return false;
	}

	return true;
}

static inline bool send_iface(gmrf_context_t *ctx, const gmrf_iface_state_t *iface, const gp_babel_packet_t *packet) {
	if (!gmrf_iface_send_bc(ctx->gmrf, iface->gmrf_iface, packet, gp_babel_packet_size(packet))) {
		gmrf_logf(ctx->gmrf, LOG_WARNING, "gmrf_iface_send_bc: %m");
		return false;
	}

	return true;
}

static inline void send_bc(gmrf_context_t *ctx, const gp_babel_packet_t *packet) {
	gmrf_iface_state_t *iface;
	for (iface = ctx->interfaces; iface; iface = iface->next)
		send_iface(ctx, iface, packet);
}

void gp_babel_send_ack(gmrf_context_t *ctx, gp_babel_neigh_t *neigh, uint16_t nonce) {
	gp_babel_packet_buf_t *buf = gp_babel_packet_alloca(GP_BABEL_PACKET_MAX);

	gp_babel_tlv_ack_t *ack = gp_babel_tlv_add(buf, TLV_ACK, sizeof(gp_babel_tlv_ack_t));
	if (!ack)
		return;

	ack->nonce = htons(nonce);

	send_neigh(ctx, neigh, &buf->packet);
}

static void add_ihus(gmrf_context_t *ctx, gp_babel_packet_buf_t *buf, const gmrf_iface_state_t *iface) {
	const gp_babel_neigh_t *neigh;

	for (neigh = iface->neighbours; neigh; neigh = neigh->next) {
		gp_babel_tlv_ihu_t *ihu = gp_babel_tlv_add(buf, TLV_IHU, sizeof(gp_babel_tlv_ihu_t)+sizeof(gmrf_addr_t));
		if (!ihu)
			return;

		ihu->ae = ADDR_ENC_GMRF;
		ihu->reserved = 0;
		ihu->rxcost = htons(gp_babel_neigh_get_rxcost(ctx, neigh));
		ihu->interval = htons(GP_BABEL_IHU_INTERVAL);
		memcpy(ihu->address, &neigh->addr, sizeof(gmrf_addr_t));
	}
}

void gp_babel_send_hellos(gmrf_context_t *ctx) {
	gmrf_logf(ctx->gmrf, LOG_DEBUG, "sending hellos...");

	gp_babel_packet_buf_t *buf = gp_babel_packet_alloca(GP_BABEL_PACKET_MAX);

	gp_babel_tlv_hello_t *hello = gp_babel_tlv_add(buf, TLV_HELLO, sizeof(gp_babel_tlv_hello_t));
	if (!hello)
		return;

	hello->reserved = 0;
	hello->interval = htons(GP_BABEL_HELLO_INTERVAL);

	uint16_t len = buf->packet.len;

	gmrf_iface_state_t *iface;
	for (iface = ctx->interfaces; iface; iface = iface->next) {
		hello->seqno = htons(ctx->hello_seqno);

		buf->packet.len = len;
		add_ihus(ctx, buf, iface);

		send_iface(ctx, iface, &buf->packet);
	}

	ctx->hello_seqno++;
}

/*static inline bool add_node_id_tlv(gp_babel_packet_buf_t *buf, const gp_babel_node_id_t *node_id) {
	gp_babel_tlv_node_id_t *tlv = gp_babel_tlv_add(buf, TLV_NODE_ID, sizeof(gp_babel_tlv_node_id_t));
	if (!tlv)
		return false;

	tlv->id = *node_id;

	return true;
	}*/

static gp_babel_tlv_update_t* add_update_tlv(gp_babel_packet_buf_t *buf, const gp_babel_node_id_t *node, gp_babel_metric_seqno_t ms) {
	gp_babel_tlv_update_t *update = gp_babel_tlv_add(buf, TLV_UPDATE, sizeof(gp_babel_tlv_update_t));

	if (!update)
		return NULL;

	update->flags = 0;
	update->reserved = 0;
	update->interval = htons(GP_BABEL_UPDATE_INTERVAL);
	update->seqno = (ms.metric != GP_BABEL_INFINITY) ? htons(ms.seqno) : 0;
	update->metric = htons(ms.metric);
	update->node = *node;

	return update;
}

static gp_babel_tlv_update_t* add_retract_tlv(gp_babel_packet_buf_t *buf, const gp_babel_node_id_t *node) {
	return add_update_tlv(buf, node, (gp_babel_metric_seqno_t){GP_BABEL_INFINITY, 0});
}

static bool add_update(gp_babel_packet_buf_t *buf, gp_babel_route_t *route, bool targeted) {
	gp_babel_tlv_update_t *update = add_update_tlv(buf, &route->node, route->metric);
	if (!update)
		return false;

	if (gp_babel_is_metric_better(route->metric, route->feasibility_distance))
		route->feasibility_distance = route->metric;

	if (!targeted)
		route->last_metric = route->metric.metric;

	return true;
}

void gp_babel_send_update(gmrf_context_t *ctx, gmrf_iface_state_t *iface, gp_babel_neigh_t *neigh) {
	gp_babel_packet_buf_t *buf = gp_babel_packet_alloca(GP_BABEL_PACKET_MAX);
	bool targeted = neigh;

	gp_babel_route_t *route;
	for (route = ctx->routes; route; route = route->next) {
		if ((route->metric.metric == GP_BABEL_INFINITY) && targeted)
			/* when targeted == true we are responding to a wildcard route request */
			continue;

		if (!add_update(buf, route, targeted)) {
			if (neigh)
				send_neigh(ctx, neigh, &buf->packet);
			else
				send_iface(ctx, iface, &buf->packet);

			buf->packet.len = 0;

			assert(add_update(buf, route, targeted));
		}
	}

	if (buf->packet.len) {
		if (neigh)
			send_neigh(ctx, neigh, &buf->packet);
		else
			send_iface(ctx, iface, &buf->packet);
	}
}

void gp_babel_send_update_for_route(gmrf_context_t *ctx, gmrf_iface_state_t *iface, gp_babel_neigh_t *neigh, gp_babel_route_t *route) {
	gp_babel_packet_buf_t *buf = gp_babel_packet_alloca(GP_BABEL_PACKET_MAX);

	assert(add_update(buf, route, neigh));

	if (neigh)
		send_neigh(ctx, neigh, &buf->packet);
	else
		send_iface(ctx, iface, &buf->packet);
}

void gp_babel_send_retract(gmrf_context_t *ctx, gmrf_iface_state_t *iface, gp_babel_neigh_t *neigh, const gp_babel_node_id_t *node) {
	gp_babel_packet_buf_t *buf = gp_babel_packet_alloca(GP_BABEL_PACKET_MAX);

	assert(add_retract_tlv(buf, node));

	if (neigh)
		send_neigh(ctx, neigh, &buf->packet);
	else
		send_iface(ctx, iface, &buf->packet);
}

void gp_babel_send_route_request(gmrf_context_t *ctx, gmrf_iface_state_t *iface, gp_babel_neigh_t *neigh, const gp_babel_node_id_t *node) {
	gp_babel_packet_buf_t *buf = gp_babel_packet_alloca(GP_BABEL_PACKET_MAX);

	gp_babel_tlv_route_req_t *req = gp_babel_tlv_add(buf, TLV_ROUTE_REQ, sizeof(gp_babel_tlv_route_req_t));
	if (!req)
		return;

	req->node = node ? (*node) : (gp_babel_node_id_t){};

	req->flags = 0;
	req->reserved = 0;

	if (neigh)
		send_neigh(ctx, neigh, &buf->packet);
	else
		send_iface(ctx, iface, &buf->packet);
}

void gp_babel_send_seqno_request(gmrf_context_t *ctx, gp_babel_neigh_t *neigh, gp_babel_route_t *route, uint16_t seqno, uint8_t hop_count) {
	gp_babel_packet_buf_t *buf = gp_babel_packet_alloca(GP_BABEL_PACKET_MAX);

	gp_babel_tlv_seqno_req_t *req = gp_babel_tlv_add(buf, TLV_SEQNO_REQ, sizeof(gp_babel_tlv_seqno_req_t));
	if (!req)
		return;

	req->seqno = htons(seqno);
	req->hop_count = hop_count;
	req->reserved = 0;
	req->node = route->node;

	if (neigh)
		send_neigh(ctx, neigh, &buf->packet);
	else
		send_bc(ctx, &buf->packet);
}