/*

 * Copyright (c) 2005, Swedish Institute of Computer Science

 * 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.

 * 3. Neither the name of the Institute nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE 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 INSTITUTE 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.

 *

 * This file is part of the uIP TCP/IP stack

 *

 */

#include <errno.h>

#include <pthread.h>

#include <stdio.h>

#include <string.h>

#include <stdlib.h>

#include <arpa/inet.h>

#include "uip.h"

#include "dhcpc.h"

#include "timer.h"

#include "pt.h"

#include "debug.h"

#include "logger.h"

#include "nic.h"

#include "nic_utils.h"

struct __attribute__ ((__packed__)) dhcp_msg {

	u8_t op, htype, hlen, hops;

	u8_t xid[4];

	u16_t secs, flags;

	u8_t ciaddr[4];

	u8_t yiaddr[4];

	u8_t siaddr[4];

	u8_t giaddr[4];

	u8_t chaddr[16];

#ifndef UIP_CONF_DHCP_LIGHT

	u8_t sname[64];

	u8_t file[128];

#endif

	u8_t options[312];

};

#define BOOTP_BROADCAST 0x8000

#define DHCP_REQUEST        1

#define DHCP_REPLY          2

#define DHCP_HTYPE_ETHERNET 1

#define DHCP_HLEN_ETHERNET  6

#define DHCP_MSG_LEN      236

#define DHCPC_SERVER_PORT  67

#define DHCPC_CLIENT_PORT  68

#define DHCPDISCOVER  1

#define DHCPOFFER     2

#define DHCPREQUEST   3

#define DHCPDECLINE   4

#define DHCPACK       5

#define DHCPNAK       6

#define DHCPRELEASE   7

#define DHCP_OPTION_SUBNET_MASK   1

#define DHCP_OPTION_ROUTER        3

#define DHCP_OPTION_DNS_SERVER    6

#define DHCP_OPTION_REQ_IPADDR   50

#define DHCP_OPTION_LEASE_TIME   51

#define DHCP_OPTION_MSG_TYPE     53

#define DHCP_OPTION_SERVER_ID    54

#define DHCP_OPTION_REQ_LIST     55

#define DHCP_OPTION_END         255

static u8_t xid[4] = { 0xad, 0xde, 0x12, 0x23 };

static const u8_t magic_cookie[4] = { 99, 130, 83, 99 };

struct dhcpc_options dhcpc_opt = {

	.enable_random_xid = 1,

};

/*---------------------------------------------------------------------------*/

static u8_t *add_msg_type(u8_t *optptr, u8_t type)

{

	*optptr++ = DHCP_OPTION_MSG_TYPE;

	*optptr++ = 1;

	*optptr++ = type;

	return optptr;

}

/*---------------------------------------------------------------------------*/

static u8_t *add_server_id(struct dhcpc_state *s, u8_t *optptr)

{

	*optptr++ = DHCP_OPTION_SERVER_ID;

	*optptr++ = 4;

	memcpy(optptr, s->serverid, 4);

	return optptr + 4;

}

/*---------------------------------------------------------------------------*/

static u8_t *add_req_ipaddr(struct dhcpc_state *s, u8_t *optptr)

{

	*optptr++ = DHCP_OPTION_REQ_IPADDR;

	*optptr++ = 4;

	memcpy(optptr, s->ipaddr, 4);

	return optptr + 4;

}

/*---------------------------------------------------------------------------*/

static u8_t *add_req_options(u8_t *optptr)

{

	*optptr++ = DHCP_OPTION_REQ_LIST;

	*optptr++ = 3;

	*optptr++ = DHCP_OPTION_SUBNET_MASK;

	*optptr++ = DHCP_OPTION_ROUTER;

	*optptr++ = DHCP_OPTION_DNS_SERVER;

	return optptr;

}

/*---------------------------------------------------------------------------*/

static u8_t *add_end(u8_t *optptr)

{

	*optptr++ = DHCP_OPTION_END;

	return optptr;

}

/*---------------------------------------------------------------------------*/

static void create_msg(struct dhcpc_state *s, struct dhcp_msg *m)

{

	m->op = DHCP_REQUEST;

	m->htype = DHCP_HTYPE_ETHERNET;

	m->hlen = s->mac_len;

	m->hops = 0;

	memcpy(m->xid, xid, sizeof(m->xid));

	m->secs = 0;

	m->flags = const_htons(BOOTP_BROADCAST);	/*  Broadcast bit. */

	/*  uip_ipaddr_copy(m->ciaddr, uip_hostaddr); */

	memcpy(m->ciaddr, s->ustack->hostaddr, sizeof(m->ciaddr));

	memset(m->yiaddr, 0, sizeof(m->yiaddr));

	memset(m->siaddr, 0, sizeof(m->siaddr));

	memset(m->giaddr, 0, sizeof(m->giaddr));

	memcpy(m->chaddr, s->mac_addr, s->mac_len);

	memset(&m->chaddr[s->mac_len], 0, sizeof(m->chaddr) - s->mac_len);

#ifndef UIP_CONF_DHCP_LIGHT

	memset(m->sname, 0, sizeof(m->sname));

	memset(m->file, 0, sizeof(m->file));

#endif

	memcpy(m->options, magic_cookie, sizeof(magic_cookie));

}

/*---------------------------------------------------------------------------*/

static void send_discover(struct dhcpc_state *s)

{

	u8_t *end;

	struct dhcp_msg *m = (struct dhcp_msg *)s->ustack->uip_appdata;

	create_msg(s, m);

	end = add_msg_type(&m->options[4], DHCPDISCOVER);

	end = add_req_options(end);

	end = add_end(end);

	uip_appsend(s->ustack, s->ustack->uip_appdata,

		    end - (u8_t *) s->ustack->uip_appdata);

}

/*---------------------------------------------------------------------------*/

static void send_request(struct dhcpc_state *s)

{

	u8_t *end;

	struct dhcp_msg *m = (struct dhcp_msg *)s->ustack->uip_appdata;

	create_msg(s, m);

	end = add_msg_type(&m->options[4], DHCPREQUEST);

	end = add_server_id(s, end);

	end = add_req_ipaddr(s, end);

	end = add_end(end);

	uip_appsend(s->ustack, s->ustack->uip_appdata,

		    end - (u8_t *) s->ustack->uip_appdata);

}

/*---------------------------------------------------------------------------*/

static u8_t parse_options(struct dhcpc_state *s, u8_t *optptr, int len)

{

	u8_t *end = optptr + len;

	u8_t type = 0;

	while (optptr < end) {

		switch (*optptr) {

		case DHCP_OPTION_SUBNET_MASK:

			memcpy(s->netmask, optptr + 2, 4);

			break;

		case DHCP_OPTION_ROUTER:

			memcpy(s->default_router, optptr + 2, 4);

			break;

		case DHCP_OPTION_DNS_SERVER:

			memcpy(s->dnsaddr, optptr + 2, 4);

			break;

		case DHCP_OPTION_MSG_TYPE:

			type = *(optptr + 2);

			break;

		case DHCP_OPTION_SERVER_ID:

			memcpy(s->serverid, optptr + 2, 4);

			break;

		case DHCP_OPTION_LEASE_TIME:

			memcpy(s->lease_time, optptr + 2, 4);

			break;

		case DHCP_OPTION_END:

			return type;

		}

		optptr += optptr[1] + 2;

	}

	return type;

}

/*---------------------------------------------------------------------------*/

static u8_t parse_msg(struct dhcpc_state *s)

{

	struct dhcp_msg *m = (struct dhcp_msg *)s->ustack->uip_appdata;

	if (m->op == DHCP_REPLY &&

	    memcmp(m->xid, xid, sizeof(xid)) == 0 &&

	    memcmp(m->chaddr, s->mac_addr, s->mac_len) == 0) {

		memcpy(s->ipaddr, m->yiaddr, 4);

		return parse_options(s, &m->options[4], uip_datalen(s->ustack));

	}

	return 0;

}

/*---------------------------------------------------------------------------*/

static PT_THREAD(handle_dhcp(struct uip_stack *ustack))

{

	struct dhcpc_state *s;

	s = ustack->dhcpc;

	if (s == NULL) {

		LOG_WARN("Could not find dhcpc state");

		return PT_ENDED;

	}

	PT_BEGIN(&s->pt);

	/* try_again: */

	s->state = STATE_SENDING;

	s->ticks = CLOCK_SECOND;

	do {

		send_discover(s);

		timer_set(&s->timer, s->ticks);

		PT_WAIT_UNTIL(&s->pt, uip_newdata(s->ustack)

			      || timer_expired(&s->timer));

		if (uip_newdata(s->ustack) && parse_msg(s) == DHCPOFFER) {

			s->state = STATE_OFFER_RECEIVED;

			break;

		}

		if (s->ticks < CLOCK_SECOND * 60)

			s->ticks += CLOCK_SECOND;

		else

			PT_RESTART(&s->pt);

	} while (s->state != STATE_OFFER_RECEIVED);

	s->ticks = CLOCK_SECOND;

	do {

		send_request(s);

		timer_set(&s->timer, s->ticks);

		s->ustack->uip_flags &= ~UIP_NEWDATA;

		PT_WAIT_UNTIL(&s->pt, uip_newdata(s->ustack)

			      || timer_expired(&s->timer));

		if (uip_newdata(s->ustack) && parse_msg(s) == DHCPACK) {

			s->state = STATE_CONFIG_RECEIVED;

			break;

		}

		if (s->ticks <= CLOCK_SECOND * 10)

			s->ticks += CLOCK_SECOND;

		else

			PT_RESTART(&s->pt);

	} while (s->state != STATE_CONFIG_RECEIVED);

	LOG_INFO("Got IP address %d.%d.%d.%d",

		 uip_ipaddr1(s->ipaddr), uip_ipaddr2(s->ipaddr),

		 uip_ipaddr3(s->ipaddr), uip_ipaddr4(s->ipaddr));

	LOG_INFO("Got netmask %d.%d.%d.%d",

		 uip_ipaddr1(s->netmask), uip_ipaddr2(s->netmask),

		 uip_ipaddr3(s->netmask), uip_ipaddr4(s->netmask));

	LOG_INFO("Got DNS server %d.%d.%d.%d",

		 uip_ipaddr1(s->dnsaddr), uip_ipaddr2(s->dnsaddr),

		 uip_ipaddr3(s->dnsaddr), uip_ipaddr4(s->dnsaddr));

	LOG_INFO("Got default router %d.%d.%d.%d",

		 uip_ipaddr1(s->default_router), uip_ipaddr2(s->default_router),

		 uip_ipaddr3(s->default_router),

		 uip_ipaddr4(s->default_router));

	s->lease_time_nl32 =

	    ntohs(s->lease_time[0]) * 65536ul + ntohs(s->lease_time[1]);

	LOG_INFO("Lease expires in %ld seconds", s->lease_time_nl32);

	s->last_update = time(NULL);

	set_uip_stack(s->ustack,

		      (uip_ip4addr_t *) s->ipaddr,

		      (uip_ip4addr_t *) s->netmask,

		      (uip_ip4addr_t *) s->default_router,

		      (uint8_t *) s->mac_addr);

	/*  Put the stack thread back into a long sleep */

	s->nic->flags |= NIC_LONG_SLEEP;

	/*  timer_stop(&s.timer); */

	/* Handle DHCP lease expiration */

	s->ticks = CLOCK_SECOND * s->lease_time_nl32;

	timer_set(&s->timer, s->ticks);

	PT_WAIT_UNTIL(&s->pt, timer_expired(&s->timer));

	LOG_INFO("Lease expired, re-acquire IP address");

	s->nic->flags &= ~NIC_LONG_SLEEP;

	PT_RESTART(&s->pt);

	/*

	 * PT_END restarts the thread so we do this instead. Eventually we

	 * should reacquire expired leases here.

	 */

	while (1)

		PT_YIELD(&s->pt);

	PT_END(&(s->pt));

}

/*---------------------------------------------------------------------------*/

int dhcpc_init(nic_t *nic, struct uip_stack *ustack,

	       const void *mac_addr, int mac_len)

{

	uip_ip4addr_t addr;

	struct dhcpc_state *s = ustack->dhcpc;

	if (s) {

		LOG_DEBUG("DHCP: DHCP context already allocated");

		return -EALREADY;

	}

	s = malloc(sizeof(*s));

	if (s == NULL) {

		LOG_ERR("Couldn't allocate size for dhcpc info");

		return -ENOMEM;

	}

	memset(s, 0, sizeof(*s));

	s->nic = nic;

	s->ustack = ustack;

	s->mac_addr = mac_addr;

	s->mac_len = mac_len;

	s->state = STATE_INITIAL;

	/*  Initialize XID to randomly */

	if (dhcpc_opt.enable_random_xid == 1) {

		u32_t gen_xid;

		gen_xid = random();

		memcpy(xid, &gen_xid, sizeof(gen_xid));

	}

	uip_ipaddr(addr, 255, 255, 255, 255);

	s->conn = uip_udp_new(ustack, &addr, const_htons(DHCPC_SERVER_PORT));

	if (s->conn != NULL)

		uip_udp_bind(s->conn, const_htons(DHCPC_CLIENT_PORT));

	ustack->dhcpc = s;

	/* Let the RX poll value take over */

	nic->flags &= ~NIC_LONG_SLEEP;

	PT_INIT(&s->pt);

	return 0;

}

/*---------------------------------------------------------------------------*/

void dhcpc_appcall(struct uip_stack *ustack)

{

	handle_dhcp(ustack);

}

/*---------------------------------------------------------------------------*/

void dhcpc_request(struct uip_stack *ustack)

{

	struct dhcpc_state *s = ustack->dhcpc;

	if (s != NULL && s->state == STATE_INITIAL)

		handle_dhcp(ustack);

}

/*---------------------------------------------------------------------------*/