/*
 * Zebra connect code.
 * Copyright (C) 2018 Cumulus Networks, Inc.
 *               Donald Sharp
 *
 * FRR 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, or (at your option) any
 * later version.
 *
 * FRR 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; see the file COPYING; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */
#include <zebra.h>

#include "thread.h"
#include "command.h"
#include "network.h"
#include "prefix.h"
#include "routemap.h"
#include "table.h"
#include "stream.h"
#include "memory.h"
#include "zclient.h"
#include "filter.h"
#include "plist.h"
#include "log.h"
#include "nexthop.h"
#include "nexthop_group.h"

#include "pbr_nht.h"
#include "pbr_map.h"
#include "pbr_memory.h"
#include "pbr_zebra.h"
#include "pbr_debug.h"

DEFINE_MTYPE_STATIC(PBRD, PBR_INTERFACE, "PBR Interface")

/* Zebra structure to hold current status. */
struct zclient *zclient;

struct pbr_interface *pbr_if_new(struct interface *ifp)
{
	struct pbr_interface *pbr_ifp;

	zassert(ifp);
	zassert(!ifp->info);

	pbr_ifp = XCALLOC(MTYPE_PBR_INTERFACE, sizeof(*pbr_ifp));

	ifp->info = pbr_ifp;
	return pbr_ifp;
}

/* Inteface addition message from zebra. */
static int interface_add(int command, struct zclient *zclient,
			       zebra_size_t length, vrf_id_t vrf_id)
{
	struct interface *ifp;

	ifp = zebra_interface_add_read(zclient->ibuf, vrf_id);

	if (!ifp)
		return 0;

	if (!ifp->info)
		pbr_if_new(ifp);

	return 0;
}

static int interface_delete(int command, struct zclient *zclient,
			    zebra_size_t length, vrf_id_t vrf_id)
{
	struct interface *ifp;
	struct stream *s;

	s = zclient->ibuf;
	/* zebra_interface_state_read () updates interface structure in iflist
	 */
	ifp = zebra_interface_state_read(s, vrf_id);

	if (ifp == NULL)
		return 0;

	if_set_index(ifp, IFINDEX_INTERNAL);

	return 0;
}

static int interface_address_add(int command, struct zclient *zclient,
				 zebra_size_t length, vrf_id_t vrf_id)
{
	zebra_interface_address_read(command, zclient->ibuf, vrf_id);

	return 0;
}

static int interface_address_delete(int command, struct zclient *zclient,
				    zebra_size_t length, vrf_id_t vrf_id)
{
	struct connected *c;

	c = zebra_interface_address_read(command, zclient->ibuf, vrf_id);

	if (!c)
		return 0;

	connected_free(c);
	return 0;
}

static int interface_state_up(int command, struct zclient *zclient,
			      zebra_size_t length, vrf_id_t vrf_id)
{

	zebra_interface_state_read(zclient->ibuf, vrf_id);

	return 0;
}

static int interface_state_down(int command, struct zclient *zclient,
				zebra_size_t length, vrf_id_t vrf_id)
{

	zebra_interface_state_read(zclient->ibuf, vrf_id);

	return 0;
}

static int route_notify_owner(int command, struct zclient *zclient,
			      zebra_size_t length, vrf_id_t vrf_id)
{
	struct prefix p;
	enum zapi_route_notify_owner note;
	uint32_t table_id;
	char buf[PREFIX_STRLEN];

	prefix2str(&p, buf, sizeof(buf));

	if (!zapi_route_notify_decode(zclient->ibuf, &p, &table_id, &note))
		return -1;

	switch (note) {
	case ZAPI_ROUTE_FAIL_INSTALL:
		DEBUGD(&pbr_dbg_zebra,
		       "%s: [%s] Route install failure for table: %u",
		       __PRETTY_FUNCTION__, buf, table_id);
		break;
	case ZAPI_ROUTE_BETTER_ADMIN_WON:
		DEBUGD(&pbr_dbg_zebra,
		       "%s: [%s] Route better admin distance won for table: %u",
		       __PRETTY_FUNCTION__, buf, table_id);
		break;
	case ZAPI_ROUTE_INSTALLED:
		DEBUGD(&pbr_dbg_zebra,
		       "%s: [%s] Route installed succeeded for table: %u",
		       __PRETTY_FUNCTION__, buf, table_id);
		pbr_nht_route_installed_for_table(table_id);
		break;
	case ZAPI_ROUTE_REMOVED:
		DEBUGD(&pbr_dbg_zebra,
		       "%s: [%s] Route Removed succeeded for table: %u",
		       __PRETTY_FUNCTION__, buf, table_id);
		pbr_nht_route_removed_for_table(table_id);
		break;
	case ZAPI_ROUTE_REMOVE_FAIL:
		DEBUGD(&pbr_dbg_zebra,
		       "%s: [%s] Route remove fail for table: %u",
		       __PRETTY_FUNCTION__, buf, table_id);
		break;
	}

	return 0;
}

static int rule_notify_owner(int command, struct zclient *zclient,
			     zebra_size_t length, vrf_id_t vrf_id)
{
	uint32_t seqno, priority, unique;
	enum zapi_rule_notify_owner note;
	struct pbr_map_sequence *pbrms;
	struct pbr_map_interface *pmi;
	ifindex_t ifi;
	uint64_t installed;

	if (!zapi_rule_notify_decode(zclient->ibuf, &seqno, &priority, &unique,
				     &ifi, &note))
		return -1;

	pmi = NULL;
	pbrms = pbrms_lookup_unique(unique, ifi, &pmi);
	if (!pbrms) {
		DEBUGD(&pbr_dbg_zebra,
		       "%s: Failure to lookup pbrms based upon %u",
		       __PRETTY_FUNCTION__, unique);
		return 0;
	}

	installed = 1 << pmi->install_bit;

	switch (note) {
	case ZAPI_RULE_FAIL_INSTALL:
		DEBUGD(&pbr_dbg_zebra, "%s: Received RULE_FAIL_INSTALL",
		       __PRETTY_FUNCTION__);
		pbrms->installed &= ~installed;
		break;
	case ZAPI_RULE_INSTALLED:
		pbrms->installed |= installed;
		DEBUGD(&pbr_dbg_zebra, "%s: Received RULE_INSTALLED",
		       __PRETTY_FUNCTION__);
		break;
	case ZAPI_RULE_FAIL_REMOVE:
	case ZAPI_RULE_REMOVED:
		pbrms->installed &= ~installed;
		DEBUGD(&pbr_dbg_zebra, "%s: Received RULE REMOVED",
		       __PRETTY_FUNCTION__);
		break;
	}

	return 0;
}

static void zebra_connected(struct zclient *zclient)
{
	zclient_send_reg_requests(zclient, VRF_DEFAULT);
}

static void route_add_helper(struct zapi_route *api, struct nexthop_group nhg,
			     uint8_t install_afi)
{
	struct zapi_nexthop *api_nh;
	struct nexthop *nhop;
	int i;

	api->prefix.family = install_afi;

	i = 0;
	for (ALL_NEXTHOPS(nhg, nhop)) {
		api_nh = &api->nexthops[i];
		api_nh->vrf_id = nhop->vrf_id;
		api_nh->type = nhop->type;
		switch (nhop->type) {
		case NEXTHOP_TYPE_IPV4:
			api_nh->gate.ipv4 = nhop->gate.ipv4;
			break;
		case NEXTHOP_TYPE_IPV4_IFINDEX:
			api_nh->gate.ipv4 = nhop->gate.ipv4;
			api_nh->ifindex = nhop->ifindex;
			break;
		case NEXTHOP_TYPE_IFINDEX:
			api_nh->ifindex = nhop->ifindex;
			break;
		case NEXTHOP_TYPE_IPV6:
			memcpy(&api_nh->gate.ipv6, &nhop->gate.ipv6, 16);
			break;
		case NEXTHOP_TYPE_IPV6_IFINDEX:
			api_nh->ifindex = nhop->ifindex;
			memcpy(&api_nh->gate.ipv6, &nhop->gate.ipv6, 16);
			break;
		case NEXTHOP_TYPE_BLACKHOLE:
			api_nh->bh_type = nhop->bh_type;
			break;
		}
		i++;
	}
	api->nexthop_num = i;

	zclient_route_send(ZEBRA_ROUTE_ADD, zclient, api);
}

/*
 * This function assumes a default route is being
 * installed into the appropriate tableid
 */
void route_add(struct pbr_nexthop_group_cache *pnhgc, struct nexthop_group nhg,
	       afi_t install_afi)
{
	struct zapi_route api;

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

	api.vrf_id = VRF_DEFAULT;
	api.type = ZEBRA_ROUTE_PBR;
	api.safi = SAFI_UNICAST;
	/*
	 * Sending a default route
	 */
	api.tableid = pnhgc->table_id;
	SET_FLAG(api.flags, ZEBRA_FLAG_ALLOW_RECURSION);
	SET_FLAG(api.message, ZAPI_MESSAGE_TABLEID);
	SET_FLAG(api.message, ZAPI_MESSAGE_NEXTHOP);
	switch (install_afi) {
	case AFI_MAX:
		route_add_helper(&api, nhg, AF_INET);
		route_add_helper(&api, nhg, AF_INET6);
		break;
	case AFI_IP:
		route_add_helper(&api, nhg, AF_INET);
		break;
	case AFI_IP6:
		route_add_helper(&api, nhg, AF_INET6);
		break;
	case AFI_L2VPN:
		DEBUGD(&pbr_dbg_zebra,
		       "%s: Asked to install unsupported route type: L2VPN",
		       __PRETTY_FUNCTION__);
		break;
	}
}

/*
 * This function assumes a default route is being
 * removed from the appropriate tableid
 */
void route_delete(struct pbr_nexthop_group_cache *pnhgc, afi_t afi)
{
	struct zapi_route api;

	memset(&api, 0, sizeof(api));
	api.vrf_id = VRF_DEFAULT;
	api.type = ZEBRA_ROUTE_PBR;
	api.safi = SAFI_UNICAST;

	api.tableid = pnhgc->table_id;
	SET_FLAG(api.message, ZAPI_MESSAGE_TABLEID);

	switch (afi) {
	case AFI_IP:
		api.prefix.family = AF_INET;
		zclient_route_send(ZEBRA_ROUTE_DELETE, zclient, &api);
		break;
	case AFI_IP6:
		api.prefix.family = AF_INET6;
		zclient_route_send(ZEBRA_ROUTE_DELETE, zclient, &api);
		break;
	case AFI_MAX:
		api.prefix.family = AF_INET;
		zclient_route_send(ZEBRA_ROUTE_DELETE, zclient, &api);
		api.prefix.family = AF_INET6;
		zclient_route_send(ZEBRA_ROUTE_DELETE, zclient, &api);
		break;
	case AFI_L2VPN:
		DEBUGD(&pbr_dbg_zebra,
		       "%s: Asked to delete unsupported route type: L2VPN",
		       __PRETTY_FUNCTION__);
		break;
	}
}

static int pbr_zebra_nexthop_update(int command, struct zclient *zclient,
				    zebra_size_t length, vrf_id_t vrf_id)
{
	struct zapi_route nhr;
	char buf[PREFIX2STR_BUFFER];
	uint32_t i;

	if (!zapi_nexthop_update_decode(zclient->ibuf, &nhr)) {
		zlog_warn("Failure to decode Nexthop update message");
		return 0;
	}

	if (DEBUG_MODE_CHECK(&pbr_dbg_zebra, DEBUG_MODE_ALL)) {

		DEBUGD(&pbr_dbg_zebra, "%s: Received Nexthop update: %s",
		       __PRETTY_FUNCTION__,
		       prefix2str(&nhr.prefix, buf, sizeof(buf)));

		DEBUGD(&pbr_dbg_zebra, "%s: (\tNexthops(%u)",
		       __PRETTY_FUNCTION__, nhr.nexthop_num);

		for (i = 0; i < nhr.nexthop_num; i++) {
			DEBUGD(&pbr_dbg_zebra,
			       "%s: \tType: %d: vrf: %d, ifindex: %d gate: %s",
			       __PRETTY_FUNCTION__, nhr.nexthops[i].type,
			       nhr.nexthops[i].vrf_id, nhr.nexthops[i].ifindex,
			       inet_ntoa(nhr.nexthops[i].gate.ipv4));
		}
	}

	pbr_nht_nexthop_update(&nhr);
	return 1;
}

extern struct zebra_privs_t pbr_privs;

void pbr_zebra_init(void)
{
	struct zclient_options opt = { .receive_notify = true };

	zclient = zclient_new(master, &opt);

	zclient_init(zclient, ZEBRA_ROUTE_PBR, 0, &pbr_privs);
	zclient->zebra_connected = zebra_connected;
	zclient->interface_add = interface_add;
	zclient->interface_delete = interface_delete;
	zclient->interface_up = interface_state_up;
	zclient->interface_down = interface_state_down;
	zclient->interface_address_add = interface_address_add;
	zclient->interface_address_delete = interface_address_delete;
	zclient->route_notify_owner = route_notify_owner;
	zclient->rule_notify_owner = rule_notify_owner;
	zclient->nexthop_update = pbr_zebra_nexthop_update;
}

void pbr_send_rnh(struct nexthop *nhop, bool reg)
{
	uint32_t command;
	struct prefix p;

	command = (reg) ?
		ZEBRA_NEXTHOP_REGISTER : ZEBRA_NEXTHOP_UNREGISTER;

	memset(&p, 0, sizeof(p));
	switch (nhop->type) {
	case NEXTHOP_TYPE_IFINDEX:
	case NEXTHOP_TYPE_BLACKHOLE:
		return;
	case NEXTHOP_TYPE_IPV4:
	case NEXTHOP_TYPE_IPV4_IFINDEX:
		p.family = AF_INET;
		p.u.prefix4.s_addr = nhop->gate.ipv4.s_addr;
		p.prefixlen = 32;
		break;
	case NEXTHOP_TYPE_IPV6:
	case NEXTHOP_TYPE_IPV6_IFINDEX:
		p.family = AF_INET6;
		memcpy(&p.u.prefix6, &nhop->gate.ipv6, 16);
		p.prefixlen = 128;
		break;
	}

	if (zclient_send_rnh(zclient, command, &p,
			     false, nhop->vrf_id) < 0) {
		zlog_warn("%s: Failure to send nexthop to zebra",
			  __PRETTY_FUNCTION__);
	}
}

static void pbr_encode_pbr_map_sequence_prefix(struct stream *s,
					       struct prefix *p,
					       unsigned char  family)
{
	struct prefix any;

	if (!p) {
		memset(&any, 0, sizeof(any));
		any.family = family;
		p = &any;
	}

	stream_putc(s, p->family);
	stream_putc(s, p->prefixlen);
	stream_put(s, &p->u.prefix, prefix_blen(p));
}

static void pbr_encode_pbr_map_sequence(struct stream *s,
					struct pbr_map_sequence *pbrms,
					struct interface *ifp)
{
	unsigned char family;

	family = AF_INET;
	if (pbrms->family)
		family = pbrms->family;

	stream_putl(s, pbrms->seqno);
	stream_putl(s, pbrms->ruleno);
	stream_putl(s, pbrms->unique);
	pbr_encode_pbr_map_sequence_prefix(s, pbrms->src, family);
	stream_putw(s, 0);  /* src port */
	pbr_encode_pbr_map_sequence_prefix(s, pbrms->dst, family);
	stream_putw(s, 0);  /* dst port */
	stream_putl(s, 0);  /* fwmark */
	if (pbrms->nhgrp_name)
		stream_putl(s, pbr_nht_get_table(pbrms->nhgrp_name));
	else if (pbrms->nhg)
		stream_putl(s, pbr_nht_get_table(pbrms->internal_nhg_name));
	stream_putl(s, ifp->ifindex);
}

void pbr_send_pbr_map(struct pbr_map_sequence *pbrms,
		      struct pbr_map_interface *pmi, bool install)
{
	struct pbr_map *pbrm = pbrms->parent;
	struct stream *s;
	uint64_t is_installed = (uint64_t)1 << pmi->install_bit;

	is_installed &= pbrms->installed;

	DEBUGD(&pbr_dbg_zebra, "%s: for %s %d(%" PRIu64 ")",
	       __PRETTY_FUNCTION__, pbrm->name, install, is_installed);

	/*
	 * If we are installed and asked to do so again
	 * just return.  If we are not installed and asked
	 * and asked to delete just return;
	 */
	if (install && is_installed)
		return;

	if (!install && !is_installed)
		return;

	s = zclient->obuf;
	stream_reset(s);

	zclient_create_header(s,
			      install ? ZEBRA_RULE_ADD : ZEBRA_RULE_DELETE,
			      VRF_DEFAULT);

	/*
	 * We are sending one item at a time at the moment
	 */
	stream_putl(s, 1);

	DEBUGD(&pbr_dbg_zebra, "%s: \t%s %s %d %s %u",
	       __PRETTY_FUNCTION__, install ? "Installing" : "Deleting",
	       pbrm->name, install, pmi->ifp->name, pmi->delete);

	pbr_encode_pbr_map_sequence(s, pbrms, pmi->ifp);

	stream_putw_at(s, 0, stream_get_endp(s));

	zclient_send_message(zclient);
}