/*
   *	Copied from Linux Monitor (LiMon) - Networking.
   *
   *	Copyright 1994 - 2000 Neil Russell.
   *	(See License)
   *	Copyright 2000 Roland Borde
   *	Copyright 2000 Paolo Scaffardi
   *	Copyright 2000-2002 Wolfgang Denk, wd@denx.de
   */
  
  /*
   * General Desription:
   *
   * The user interface supports commands for BOOTP, RARP, and TFTP.
   * Also, we support ARP internally. Depending on available data,
   * these interact as follows:
   *
   * BOOTP:
   *
   *	Prerequisites:	- own ethernet address
   *	We want:	- own IP address
   *			- TFTP server IP address
   *			- name of bootfile
   *	Next step:	ARP
   *

   * LINK_LOCAL:
   *
   *	Prerequisites:	- own ethernet address
   *	We want:	- own IP address
   *	Next step:	ARP
   *

   * RARP:
   *
   *	Prerequisites:	- own ethernet address
   *	We want:	- own IP address
   *			- TFTP server IP address
   *	Next step:	ARP
   *
   * ARP:
   *
   *	Prerequisites:	- own ethernet address
   *			- own IP address
   *			- TFTP server IP address
   *	We want:	- TFTP server ethernet address
   *	Next step:	TFTP
   *
   * DHCP:
   *

   *     Prerequisites:	- own ethernet address
   *     We want:		- IP, Netmask, ServerIP, Gateway IP
   *			- bootfilename, lease time
   *     Next step:	- TFTP

   *
   * TFTP:
   *
   *	Prerequisites:	- own ethernet address
   *			- own IP address
   *			- TFTP server IP address
   *			- TFTP server ethernet address
   *			- name of bootfile (if unknown, we use a default name
   *			  derived from our own IP address)
   *	We want:	- load the boot file
   *	Next step:	none

   *
   * NFS:
   *
   *	Prerequisites:	- own ethernet address
   *			- own IP address
   *			- name of bootfile (if unknown, we use a default name
   *			  derived from our own IP address)
   *	We want:	- load the boot file
   *	Next step:	none

   *
   * SNTP:
   *

   *	Prerequisites:	- own ethernet address

   *			- own IP address
   *	We want:	- network time
   *	Next step:	none

   */
  
  
  #include <common.h>

  #include <command.h>

  #include <environment.h>

  #include <net.h>

  #if defined(CONFIG_STATUS_LED)

  #include <miiphy.h>

  #include <status_led.h>

  #endif

  #include <watchdog.h>
  #include <linux/compiler.h>
  #include "arp.h"
  #include "bootp.h"

  #include "cdp.h"

  #if defined(CONFIG_CMD_DNS)
  #include "dns.h"
  #endif

  #include "link_local.h"

  #include "nfs.h"

  #include "ping.h"

  #include "rarp.h"
  #if defined(CONFIG_CMD_SNTP)
  #include "sntp.h"
  #endif
  #include "tftp.h"

  DECLARE_GLOBAL_DATA_PTR;

  /** BOOTP EXTENTIONS **/

  /* Our subnet mask (0=unknown) */

  IPaddr_t	NetOurSubnetMask;

  /* Our gateways IP address */

  IPaddr_t	NetOurGatewayIP;

  /* Our DNS IP address */

  IPaddr_t	NetOurDNSIP;

  #if defined(CONFIG_BOOTP_DNS2)

  /* Our 2nd DNS IP address */

  IPaddr_t	NetOurDNS2IP;

  #endif
  /* Our NIS domain */

  char		NetOurNISDomain[32] = {0,};

  /* Our hostname */

  char		NetOurHostName[32] = {0,};

  /* Our bootpath */

  char		NetOurRootPath[64] = {0,};

  /* Our bootfile size in blocks */

  ushort		NetBootFileSize;

  #ifdef CONFIG_MCAST_TFTP	/* Multicast TFTP */
  IPaddr_t Mcast_addr;
  #endif

  /** END OF BOOTP EXTENTIONS **/

  /* The actual transferred size of the bootfile (in bytes) */
  ulong		NetBootFileXferSize;
  /* Our ethernet address */
  uchar		NetOurEther[6];
  /* Boot server enet address */

  uchar		NetServerEther[6];

  /* Our IP addr (0 = unknown) */
  IPaddr_t	NetOurIP;
  /* Server IP addr (0 = unknown) */
  IPaddr_t	NetServerIP;
  /* Current receive packet */

  uchar *NetRxPacket;

  /* Current rx packet length */
  int		NetRxPacketLen;
  /* IP packet ID */
  unsigned	NetIPID;
  /* Ethernet bcast address */

  uchar		NetBcastAddr[6] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
  uchar		NetEtherNullAddr[6];

  #ifdef CONFIG_API

  void		(*push_packet)(void *, int len) = 0;

  #endif

  /* Network loop state */

  enum net_loop_state net_state;

  /* Tried all network devices */

  int		NetRestartWrap;

  /* Network loop restarted */

  static int	NetRestarted;

  /* At least one device configured */

  static int	NetDevExists;

  /* XXX in both little & big endian machines 0xFFFF == ntohs(-1) */

  /* default is without VLAN */
  ushort		NetOurVLAN = 0xFFFF;
  /* ditto */
  ushort		NetOurNativeVLAN = 0xFFFF;

  /* Boot File name */
  char		BootFile[128];

  #if defined(CONFIG_CMD_SNTP)

  /* NTP server IP address */
  IPaddr_t	NetNtpServerIP;
  /* offset time from UTC */

  int		NetTimeOffset;

  #endif

  static uchar PktBuf[(PKTBUFSRX+1) * PKTSIZE_ALIGN + PKTALIGN];

  /* Receive packet */

  uchar *NetRxPackets[PKTBUFSRX];

  /* Current UDP RX packet handler */
  static rxhand_f *udp_packet_handler;
  /* Current ARP RX packet handler */
  static rxhand_f *arp_packet_handler;

  #ifdef CONFIG_CMD_TFTPPUT

  /* Current ICMP rx handler */
  static rxhand_icmp_f *packet_icmp_handler;

  #endif

  /* Current timeout handler */
  static thand_f *timeHandler;
  /* Time base value */
  static ulong	timeStart;
  /* Current timeout value */
  static ulong	timeDelta;
  /* THE transmit packet */

  uchar *NetTxPacket;

  static int net_check_prereq(enum proto_t protocol);

  static int NetTryCount;

  int __maybe_unused net_busy_flag;

  /**********************************************************************/

  static int on_bootfile(const char *name, const char *value, enum env_op op,
  	int flags)
  {
  	switch (op) {
  	case env_op_create:
  	case env_op_overwrite:
  		copy_filename(BootFile, value, sizeof(BootFile));
  		break;
  	default:
  		break;
  	}
  
  	return 0;
  }
  U_BOOT_ENV_CALLBACK(bootfile, on_bootfile);

  /*
   * Check if autoload is enabled. If so, use either NFS or TFTP to download
   * the boot file.
   */
  void net_auto_load(void)
  {

  #if defined(CONFIG_CMD_NFS)

  	const char *s = getenv("autoload");

  	if (s != NULL && strcmp(s, "NFS") == 0) {
  		/*
  		 * Use NFS to load the bootfile.
  		 */
  		NfsStart();
  		return;
  	}

  #endif

  	if (getenv_yesno("autoload") == 0) {
  		/*
  		 * Just use BOOTP/RARP to configure system;
  		 * Do not use TFTP to load the bootfile.
  		 */
  		net_set_state(NETLOOP_SUCCESS);
  		return;

  	}
  	TftpStart(TFTPGET);
  }

  static void NetInitLoop(void)

  {

  	static int env_changed_id;

  	int env_id = get_env_id();

  
  	/* update only when the environment has changed */

  	if (env_changed_id != env_id) {

  		NetOurIP = getenv_IPaddr("ipaddr");

  		NetOurGatewayIP = getenv_IPaddr("gatewayip");
  		NetOurSubnetMask = getenv_IPaddr("netmask");
  		NetServerIP = getenv_IPaddr("serverip");

  		NetOurNativeVLAN = getenv_VLAN("nvlan");

  		NetOurVLAN = getenv_VLAN("vlan");

  #if defined(CONFIG_CMD_DNS)
  		NetOurDNSIP = getenv_IPaddr("dnsip");
  #endif

  		env_changed_id = env_id;

  	}

  	if (eth_get_dev())
  		memcpy(NetOurEther, eth_get_dev()->enetaddr, 6);

  	return;

  }

  static void net_clear_handlers(void)
  {
  	net_set_udp_handler(NULL);
  	net_set_arp_handler(NULL);
  	NetSetTimeout(0, NULL);
  }
  
  static void net_cleanup_loop(void)
  {
  	net_clear_handlers();
  }

  void net_init(void)
  {
  	static int first_call = 1;
  
  	if (first_call) {
  		/*
  		 *	Setup packet buffers, aligned correctly.
  		 */
  		int i;
  
  		NetTxPacket = &PktBuf[0] + (PKTALIGN - 1);
  		NetTxPacket -= (ulong)NetTxPacket % PKTALIGN;
  		for (i = 0; i < PKTBUFSRX; i++)
  			NetRxPackets[i] = NetTxPacket + (i + 1) * PKTSIZE_ALIGN;
  
  		ArpInit();
  		net_clear_handlers();
  
  		/* Only need to setup buffer pointers once. */
  		first_call = 0;
  	}
  
  	NetInitLoop();
  }

  /**********************************************************************/

  /*
   *	Main network processing loop.
   */

  int NetLoop(enum proto_t protocol)

  {

  	bd_t *bd = gd->bd;

  	int ret = -1;

  	NetRestarted = 0;
  	NetDevExists = 0;

  	NetTryCount = 1;

  	debug_cond(DEBUG_INT_STATE, "--- NetLoop Entry
  ");

  	bootstage_mark_name(BOOTSTAGE_ID_ETH_START, "eth_start");

  	net_init();

  	if (eth_is_on_demand_init() || protocol != NETCONS) {

  		eth_halt();

  		eth_set_current();
  		if (eth_init(bd) < 0) {
  			eth_halt();
  			return -1;
  		}
  	} else
  		eth_init_state_only(bd);

  
  restart:

  #ifdef CONFIG_USB_KEYBOARD
  	net_busy_flag = 0;
  #endif

  	net_set_state(NETLOOP_CONTINUE);

  
  	/*
  	 *	Start the ball rolling with the given start function.  From
  	 *	here on, this code is a state machine driven by received
  	 *	packets and timer events.
  	 */

  	debug_cond(DEBUG_INT_STATE, "--- NetLoop Init
  ");

  	NetInitLoop();

  	switch (net_check_prereq(protocol)) {

  	case 1:
  		/* network not configured */

  		eth_halt();

  		return -1;

  	case 2:
  		/* network device not configured */
  		break;

  
  	case 0:

  		NetDevExists = 1;

  		NetBootFileXferSize = 0;

  		switch (protocol) {

  		case TFTPGET:

  #ifdef CONFIG_CMD_TFTPPUT
  		case TFTPPUT:
  #endif

  			/* always use ARP to get server ethernet address */

  			TftpStart(protocol);

  			break;

  #ifdef CONFIG_CMD_TFTPSRV
  		case TFTPSRV:
  			TftpStartServer();
  			break;
  #endif

  #if defined(CONFIG_CMD_DHCP)

  		case DHCP:

  			BootpTry = 0;

  			NetOurIP = 0;

  			DhcpRequest();		/* Basically same as BOOTP */
  			break;

  #endif

  
  		case BOOTP:
  			BootpTry = 0;

  			NetOurIP = 0;

  			BootpRequest();

  			break;

  #if defined(CONFIG_CMD_RARP)

  		case RARP:
  			RarpTry = 0;

  			NetOurIP = 0;

  			RarpRequest();

  			break;

  #endif

  #if defined(CONFIG_CMD_PING)

  		case PING:

  			ping_start();

  			break;
  #endif

  #if defined(CONFIG_CMD_NFS)

  		case NFS:
  			NfsStart();
  			break;
  #endif

  #if defined(CONFIG_CMD_CDP)

  		case CDP:
  			CDPStart();
  			break;
  #endif

  #ifdef CONFIG_NETCONSOLE
  		case NETCONS:
  			NcStart();
  			break;
  #endif

  #if defined(CONFIG_CMD_SNTP)

  		case SNTP:
  			SntpStart();
  			break;
  #endif

  #if defined(CONFIG_CMD_DNS)
  		case DNS:
  			DnsStart();
  			break;
  #endif

  #if defined(CONFIG_CMD_LINK_LOCAL)
  		case LINKLOCAL:
  			link_local_start();
  			break;
  #endif

  		default:
  			break;
  		}

  		break;
  	}

  #if defined(CONFIG_MII) || defined(CONFIG_CMD_MII)

  #if	defined(CONFIG_SYS_FAULT_ECHO_LINK_DOWN)	&& \
  	defined(CONFIG_STATUS_LED)			&& \
  	defined(STATUS_LED_RED)

  	/*

  	 * Echo the inverted link state to the fault LED.

  	 */

  	if (miiphy_link(eth_get_dev()->name, CONFIG_SYS_FAULT_MII_ADDR))

  		status_led_set(STATUS_LED_RED, STATUS_LED_OFF);

  	else

  		status_led_set(STATUS_LED_RED, STATUS_LED_ON);

  #endif /* CONFIG_SYS_FAULT_ECHO_LINK_DOWN, ... */

  #endif /* CONFIG_MII, ... */

  #ifdef CONFIG_USB_KEYBOARD
  	net_busy_flag = 1;
  #endif

  
  	/*
  	 *	Main packet reception loop.  Loop receiving packets until

  	 *	someone sets `net_state' to a state that terminates.

  	 */
  	for (;;) {
  		WATCHDOG_RESET();
  #ifdef CONFIG_SHOW_ACTIVITY

  		show_activity(1);

  #endif
  		/*
  		 *	Check the ethernet for a new packet.  The ethernet
  		 *	receive routine will process it.
  		 */

  		eth_rx();

  
  		/*
  		 *	Abort if ctrl-c was pressed.
  		 */
  		if (ctrlc()) {

  			/* cancel any ARP that may not have completed */
  			NetArpWaitPacketIP = 0;

  			net_cleanup_loop();

  			eth_halt();

  			/* Invalidate the last protocol */
  			eth_set_last_protocol(BOOTP);

  			puts("
  Abort
  ");

  			/* include a debug print as well incase the debug
  			   messages are directed to stderr */
  			debug_cond(DEBUG_INT_STATE, "--- NetLoop Abort!
  ");

  			goto done;

  		}

  		ArpTimeoutCheck();

  
  		/*
  		 *	Check for a timeout, and run the timeout handler
  		 *	if we have one.
  		 */

  		if (timeHandler && ((get_timer(0) - timeStart) > timeDelta)) {

  			thand_f *x;

  #if defined(CONFIG_MII) || defined(CONFIG_CMD_MII)

  #if	defined(CONFIG_SYS_FAULT_ECHO_LINK_DOWN)	&& \
  	defined(CONFIG_STATUS_LED)			&& \
  	defined(STATUS_LED_RED)

  			/*

  			 * Echo the inverted link state to the fault LED.

  			 */

  			if (miiphy_link(eth_get_dev()->name,

  				       CONFIG_SYS_FAULT_MII_ADDR)) {

  				status_led_set(STATUS_LED_RED, STATUS_LED_OFF);

  			} else {

  				status_led_set(STATUS_LED_RED, STATUS_LED_ON);

  			}

  #endif /* CONFIG_SYS_FAULT_ECHO_LINK_DOWN, ... */

  #endif /* CONFIG_MII, ... */

  			debug_cond(DEBUG_INT_STATE, "--- NetLoop timeout
  ");

  			x = timeHandler;
  			timeHandler = (thand_f *)0;
  			(*x)();
  		}

  		switch (net_state) {

  
  		case NETLOOP_RESTART:

  			NetRestarted = 1;

  			goto restart;
  
  		case NETLOOP_SUCCESS:

  			net_cleanup_loop();

  			if (NetBootFileXferSize > 0) {

  				printf("Bytes transferred = %ld (%lx hex)
  ",
  					NetBootFileXferSize,
  					NetBootFileXferSize);

  				setenv_hex("filesize", NetBootFileXferSize);
  				setenv_hex("fileaddr", load_addr);

  			}

  			if (protocol != NETCONS)
  				eth_halt();
  			else
  				eth_halt_state_only();
  
  			eth_set_last_protocol(protocol);

  			ret = NetBootFileXferSize;

  			debug_cond(DEBUG_INT_STATE, "--- NetLoop Success!
  ");

  			goto done;

  
  		case NETLOOP_FAIL:

  			net_cleanup_loop();

  			/* Invalidate the last protocol */
  			eth_set_last_protocol(BOOTP);

  			debug_cond(DEBUG_INT_STATE, "--- NetLoop Fail!
  ");

  			goto done;

  
  		case NETLOOP_CONTINUE:
  			continue;

  		}
  	}

  
  done:

  #ifdef CONFIG_USB_KEYBOARD
  	net_busy_flag = 0;
  #endif

  #ifdef CONFIG_CMD_TFTPPUT

  	/* Clear out the handlers */

  	net_set_udp_handler(NULL);

  	net_set_icmp_handler(NULL);

  #endif

  	return ret;

  }
  
  /**********************************************************************/
  
  static void
  startAgainTimeout(void)
  {

  	net_set_state(NETLOOP_RESTART);

  }

  void NetStartAgain(void)

  {

  	char *nretry;

  	int retry_forever = 0;
  	unsigned long retrycnt = 0;
  
  	nretry = getenv("netretry");
  	if (nretry) {
  		if (!strcmp(nretry, "yes"))
  			retry_forever = 1;
  		else if (!strcmp(nretry, "no"))
  			retrycnt = 0;
  		else if (!strcmp(nretry, "once"))
  			retrycnt = 1;
  		else
  			retrycnt = simple_strtoul(nretry, NULL, 0);
  	} else
  		retry_forever = 1;
  
  	if ((!retry_forever) && (NetTryCount >= retrycnt)) {
  		eth_halt();

  		net_set_state(NETLOOP_FAIL);

  		return;
  	}

  
  	NetTryCount++;

  	eth_halt();

  #if !defined(CONFIG_NET_DO_NOT_TRY_ANOTHER)

  	eth_try_another(!NetRestarted);

  #endif

  	eth_init(gd->bd);

  	if (NetRestartWrap) {

  		NetRestartWrap = 0;

  		if (NetDevExists) {

  			NetSetTimeout(10000UL, startAgainTimeout);

  			net_set_udp_handler(NULL);

  		} else {

  			net_set_state(NETLOOP_FAIL);

  		}

  	} else {

  		net_set_state(NETLOOP_RESTART);

  	}

  }
  
  /**********************************************************************/
  /*
   *	Miscelaneous bits.
   */

  static void dummy_handler(uchar *pkt, unsigned dport,
  			IPaddr_t sip, unsigned sport,
  			unsigned len)

  {

  }

  rxhand_f *net_get_udp_handler(void)
  {
  	return udp_packet_handler;
  }

  void net_set_udp_handler(rxhand_f *f)
  {

  	debug_cond(DEBUG_INT_STATE, "--- NetLoop UDP handler set (%p)
  ", f);

  	if (f == NULL)
  		udp_packet_handler = dummy_handler;
  	else
  		udp_packet_handler = f;
  }
  
  rxhand_f *net_get_arp_handler(void)

  {

  	return arp_packet_handler;
  }
  
  void net_set_arp_handler(rxhand_f *f)
  {

  	debug_cond(DEBUG_INT_STATE, "--- NetLoop ARP handler set (%p)
  ", f);

  	if (f == NULL)
  		arp_packet_handler = dummy_handler;
  	else
  		arp_packet_handler = f;

  }

  #ifdef CONFIG_CMD_TFTPPUT

  void net_set_icmp_handler(rxhand_icmp_f *f)
  {
  	packet_icmp_handler = f;
  }

  #endif

  
  void

  NetSetTimeout(ulong iv, thand_f *f)

  {
  	if (iv == 0) {

  		debug_cond(DEBUG_INT_STATE,
  			"--- NetLoop timeout handler cancelled
  ");

  		timeHandler = (thand_f *)0;
  	} else {

  		debug_cond(DEBUG_INT_STATE,
  			"--- NetLoop timeout handler set (%p)
  ", f);

  		timeHandler = f;

  		timeStart = get_timer(0);

  		timeDelta = iv * CONFIG_SYS_HZ / 1000;

  	}
  }

  int NetSendUDPPacket(uchar *ether, IPaddr_t dest, int dport, int sport,
  		int payload_len)

  {

  	uchar *pkt;

  	int eth_hdr_size;
  	int pkt_hdr_size;

  	/* make sure the NetTxPacket is initialized (NetInit() was called) */
  	assert(NetTxPacket != NULL);
  	if (NetTxPacket == NULL)
  		return -1;

  	/* convert to new style broadcast */
  	if (dest == 0)
  		dest = 0xFFFFFFFF;
  
  	/* if broadcast, make the ether address a broadcast and don't do ARP */
  	if (dest == 0xFFFFFFFF)
  		ether = NetBcastAddr;

  	pkt = (uchar *)NetTxPacket;

  
  	eth_hdr_size = NetSetEther(pkt, ether, PROT_IP);
  	pkt += eth_hdr_size;
  	net_set_udp_header(pkt, dest, dport, sport, payload_len);
  	pkt_hdr_size = eth_hdr_size + IP_UDP_HDR_SIZE;

  	/* if MAC address was not discovered yet, do an ARP request */
  	if (memcmp(ether, NetEtherNullAddr, 6) == 0) {

  		debug_cond(DEBUG_DEV_PKT, "sending ARP for %pI4
  ", &dest);

  		/* save the ip and eth addr for the packet to send after arp */

  		NetArpWaitPacketIP = dest;
  		NetArpWaitPacketMAC = ether;

  		/* size of the waiting packet */

  		NetArpWaitTxPacketSize = pkt_hdr_size + payload_len;

  
  		/* and do the ARP request */
  		NetArpWaitTry = 1;
  		NetArpWaitTimerStart = get_timer(0);
  		ArpRequest();
  		return 1;	/* waiting */

  	} else {

  		debug_cond(DEBUG_DEV_PKT, "sending UDP to %pI4/%pM
  ",
  			&dest, ether);

  		NetSendPacket(NetTxPacket, pkt_hdr_size + payload_len);

  		return 0;	/* transmitted */

  	}

  }

  #ifdef CONFIG_IP_DEFRAG
  /*
   * This function collects fragments in a single packet, according
   * to the algorithm in RFC815. It returns NULL or the pointer to
   * a complete packet, in static storage
   */
  #ifndef CONFIG_NET_MAXDEFRAG
  #define CONFIG_NET_MAXDEFRAG 16384
  #endif
  /*
   * MAXDEFRAG, above, is chosen in the config file and  is real data
   * so we need to add the NFS overhead, which is more than TFTP.
   * To use sizeof in the internal unnamed structures, we need a real
   * instance (can't do "sizeof(struct rpc_t.u.reply))", unfortunately).
   * The compiler doesn't complain nor allocates the actual structure
   */
  static struct rpc_t rpc_specimen;
  #define IP_PKTSIZE (CONFIG_NET_MAXDEFRAG + sizeof(rpc_specimen.u.reply))

  #define IP_MAXUDP (IP_PKTSIZE - IP_HDR_SIZE)

  
  /*
   * this is the packet being assembled, either data or frag control.
   * Fragments go by 8 bytes, so this union must be 8 bytes long
   */
  struct hole {
  	/* first_byte is address of this structure */
  	u16 last_byte;	/* last byte in this hole + 1 (begin of next hole) */
  	u16 next_hole;	/* index of next (in 8-b blocks), 0 == none */
  	u16 prev_hole;	/* index of prev, 0 == none */
  	u16 unused;
  };

  static struct ip_udp_hdr *__NetDefragment(struct ip_udp_hdr *ip, int *lenp)

  {

  	static uchar pkt_buff[IP_PKTSIZE] __aligned(PKTALIGN);

  	static u16 first_hole, total_len;
  	struct hole *payload, *thisfrag, *h, *newh;

  	struct ip_udp_hdr *localip = (struct ip_udp_hdr *)pkt_buff;

  	uchar *indata = (uchar *)ip;
  	int offset8, start, len, done = 0;
  	u16 ip_off = ntohs(ip->ip_off);
  
  	/* payload starts after IP header, this fragment is in there */

  	payload = (struct hole *)(pkt_buff + IP_HDR_SIZE);

  	offset8 =  (ip_off & IP_OFFS);
  	thisfrag = payload + offset8;
  	start = offset8 * 8;

  	len = ntohs(ip->ip_len) - IP_HDR_SIZE;

  
  	if (start + len > IP_MAXUDP) /* fragment extends too far */
  		return NULL;
  
  	if (!total_len || localip->ip_id != ip->ip_id) {
  		/* new (or different) packet, reset structs */
  		total_len = 0xffff;
  		payload[0].last_byte = ~0;
  		payload[0].next_hole = 0;
  		payload[0].prev_hole = 0;
  		first_hole = 0;
  		/* any IP header will work, copy the first we received */

  		memcpy(localip, ip, IP_HDR_SIZE);

  	}
  
  	/*
  	 * What follows is the reassembly algorithm. We use the payload
  	 * array as a linked list of hole descriptors, as each hole starts
  	 * at a multiple of 8 bytes. However, last byte can be whatever value,
  	 * so it is represented as byte count, not as 8-byte blocks.
  	 */
  
  	h = payload + first_hole;
  	while (h->last_byte < start) {
  		if (!h->next_hole) {
  			/* no hole that far away */
  			return NULL;
  		}
  		h = payload + h->next_hole;
  	}

  	/* last fragment may be 1..7 bytes, the "+7" forces acceptance */
  	if (offset8 + ((len + 7) / 8) <= h - payload) {

  		/* no overlap with holes (dup fragment?) */
  		return NULL;
  	}
  
  	if (!(ip_off & IP_FLAGS_MFRAG)) {
  		/* no more fragmentss: truncate this (last) hole */
  		total_len = start + len;
  		h->last_byte = start + len;
  	}
  
  	/*
  	 * There is some overlap: fix the hole list. This code doesn't
  	 * deal with a fragment that overlaps with two different holes
  	 * (thus being a superset of a previously-received fragment).
  	 */

  	if ((h >= thisfrag) && (h->last_byte <= start + len)) {

  		/* complete overlap with hole: remove hole */
  		if (!h->prev_hole && !h->next_hole) {
  			/* last remaining hole */
  			done = 1;
  		} else if (!h->prev_hole) {
  			/* first hole */
  			first_hole = h->next_hole;
  			payload[h->next_hole].prev_hole = 0;
  		} else if (!h->next_hole) {
  			/* last hole */
  			payload[h->prev_hole].next_hole = 0;
  		} else {
  			/* in the middle of the list */
  			payload[h->next_hole].prev_hole = h->prev_hole;
  			payload[h->prev_hole].next_hole = h->next_hole;
  		}
  
  	} else if (h->last_byte <= start + len) {
  		/* overlaps with final part of the hole: shorten this hole */
  		h->last_byte = start;
  
  	} else if (h >= thisfrag) {
  		/* overlaps with initial part of the hole: move this hole */
  		newh = thisfrag + (len / 8);
  		*newh = *h;
  		h = newh;
  		if (h->next_hole)
  			payload[h->next_hole].prev_hole = (h - payload);
  		if (h->prev_hole)
  			payload[h->prev_hole].next_hole = (h - payload);
  		else
  			first_hole = (h - payload);
  
  	} else {
  		/* fragment sits in the middle: split the hole */
  		newh = thisfrag + (len / 8);
  		*newh = *h;
  		h->last_byte = start;
  		h->next_hole = (newh - payload);
  		newh->prev_hole = (h - payload);
  		if (newh->next_hole)
  			payload[newh->next_hole].prev_hole = (newh - payload);
  	}
  
  	/* finally copy this fragment and possibly return whole packet */

  	memcpy((uchar *)thisfrag, indata + IP_HDR_SIZE, len);

  	if (!done)
  		return NULL;
  
  	localip->ip_len = htons(total_len);

  	*lenp = total_len + IP_HDR_SIZE;

  	return localip;
  }

  static inline struct ip_udp_hdr *NetDefragment(struct ip_udp_hdr *ip, int *lenp)

  {
  	u16 ip_off = ntohs(ip->ip_off);
  	if (!(ip_off & (IP_OFFS | IP_FLAGS_MFRAG)))
  		return ip; /* not a fragment */
  	return __NetDefragment(ip, lenp);
  }
  
  #else /* !CONFIG_IP_DEFRAG */

  static inline struct ip_udp_hdr *NetDefragment(struct ip_udp_hdr *ip, int *lenp)

  {
  	u16 ip_off = ntohs(ip->ip_off);
  	if (!(ip_off & (IP_OFFS | IP_FLAGS_MFRAG)))
  		return ip; /* not a fragment */
  	return NULL;
  }
  #endif

  /**
   * Receive an ICMP packet. We deal with REDIRECT and PING here, and silently
   * drop others.
   *
   * @parma ip	IP packet containing the ICMP
   */

  static void receive_icmp(struct ip_udp_hdr *ip, int len,

  			IPaddr_t src_ip, struct ethernet_hdr *et)

  {

  	struct icmp_hdr *icmph = (struct icmp_hdr *)&ip->udp_src;

  
  	switch (icmph->type) {
  	case ICMP_REDIRECT:
  		if (icmph->code != ICMP_REDIR_HOST)
  			return;
  		printf(" ICMP Host Redirect to %pI4 ",
  			&icmph->un.gateway);
  		break;

  	default:

  #if defined(CONFIG_CMD_PING)

  		ping_receive(et, ip, len);

  #endif

  #ifdef CONFIG_CMD_TFTPPUT

  		if (packet_icmp_handler)
  			packet_icmp_handler(icmph->type, icmph->code,
  				ntohs(ip->udp_dst), src_ip, ntohs(ip->udp_src),
  				icmph->un.data, ntohs(ip->udp_len));

  #endif

  		break;
  	}
  }

  void

  NetReceive(uchar *inpkt, int len)

  {

  	struct ethernet_hdr *et;

  	struct ip_udp_hdr *ip;

  	IPaddr_t dst_ip;

  	IPaddr_t src_ip;

  	int eth_proto;

  #if defined(CONFIG_CMD_CDP)

  	int iscdp;
  #endif
  	ushort cti = 0, vlanid = VLAN_NONE, myvlanid, mynvlanid;

  	debug_cond(DEBUG_NET_PKT, "packet received
  ");

  	NetRxPacket = inpkt;
  	NetRxPacketLen = len;

  	et = (struct ethernet_hdr *)inpkt;

  
  	/* too small packet? */
  	if (len < ETHER_HDR_SIZE)
  		return;

  #ifdef CONFIG_API
  	if (push_packet) {
  		(*push_packet)(inpkt, len);
  		return;
  	}
  #endif

  #if defined(CONFIG_CMD_CDP)

  	/* keep track if packet is CDP */

  	iscdp = is_cdp_packet(et->et_dest);

  #endif
  
  	myvlanid = ntohs(NetOurVLAN);
  	if (myvlanid == (ushort)-1)
  		myvlanid = VLAN_NONE;
  	mynvlanid = ntohs(NetOurNativeVLAN);
  	if (mynvlanid == (ushort)-1)
  		mynvlanid = VLAN_NONE;

  	eth_proto = ntohs(et->et_protlen);

  	if (eth_proto < 1514) {

  		struct e802_hdr *et802 = (struct e802_hdr *)et;

  		/*

  		 *	Got a 802.2 packet.  Check the other protocol field.
  		 *	XXX VLAN over 802.2+SNAP not implemented!

  		 */

  		eth_proto = ntohs(et802->et_prot);

  		ip = (struct ip_udp_hdr *)(inpkt + E802_HDR_SIZE);

  		len -= E802_HDR_SIZE;

  	} else if (eth_proto != PROT_VLAN) {	/* normal packet */

  		ip = (struct ip_udp_hdr *)(inpkt + ETHER_HDR_SIZE);

  		len -= ETHER_HDR_SIZE;

  
  	} else {			/* VLAN packet */

  		struct vlan_ethernet_hdr *vet =
  			(struct vlan_ethernet_hdr *)et;

  		debug_cond(DEBUG_NET_PKT, "VLAN packet received
  ");

  		/* too small packet? */
  		if (len < VLAN_ETHER_HDR_SIZE)
  			return;
  
  		/* if no VLAN active */
  		if ((ntohs(NetOurVLAN) & VLAN_IDMASK) == VLAN_NONE

  #if defined(CONFIG_CMD_CDP)

  				&& iscdp == 0
  #endif
  				)
  			return;
  
  		cti = ntohs(vet->vet_tag);
  		vlanid = cti & VLAN_IDMASK;

  		eth_proto = ntohs(vet->vet_type);

  		ip = (struct ip_udp_hdr *)(inpkt + VLAN_ETHER_HDR_SIZE);

  		len -= VLAN_ETHER_HDR_SIZE;

  	}

  	debug_cond(DEBUG_NET_PKT, "Receive from protocol 0x%x
  ", eth_proto);

  #if defined(CONFIG_CMD_CDP)

  	if (iscdp) {

  		cdp_receive((uchar *)ip, len);

  		return;
  	}
  #endif
  
  	if ((myvlanid & VLAN_IDMASK) != VLAN_NONE) {
  		if (vlanid == VLAN_NONE)
  			vlanid = (mynvlanid & VLAN_IDMASK);
  		/* not matched? */
  		if (vlanid != (myvlanid & VLAN_IDMASK))
  			return;
  	}

  	switch (eth_proto) {

  
  	case PROT_ARP:

  		ArpReceive(et, ip, len);

  		break;

  #ifdef CONFIG_CMD_RARP

  	case PROT_RARP:

  		rarp_receive(ip, len);

  		break;

  #endif

  	case PROT_IP:

  		debug_cond(DEBUG_NET_PKT, "Got IP
  ");

  		/* Before we start poking the header, make sure it is there */

  		if (len < IP_UDP_HDR_SIZE) {
  			debug("len bad %d < %lu
  ", len,
  				(ulong)IP_UDP_HDR_SIZE);

  			return;
  		}

  		/* Check the packet length */

  		if (len < ntohs(ip->ip_len)) {

  			debug("len bad %d < %d
  ", len, ntohs(ip->ip_len));

  			return;
  		}
  		len = ntohs(ip->ip_len);

  		debug_cond(DEBUG_NET_PKT, "len=%d, v=%02x
  ",
  			len, ip->ip_hl_v & 0xff);

  		/* Can't deal with anything except IPv4 */

  		if ((ip->ip_hl_v & 0xf0) != 0x40)

  			return;

  		/* Can't deal with IP options (headers != 20 bytes) */

  		if ((ip->ip_hl_v & 0x0f) > 0x05)

  			return;

  		/* Check the Checksum of the header */

  		if (!NetCksumOk((uchar *)ip, IP_HDR_SIZE / 2)) {

  			debug("checksum bad
  ");

  			return;
  		}

  		/* If it is not for us, ignore it */

  		dst_ip = NetReadIP(&ip->ip_dst);
  		if (NetOurIP && dst_ip != NetOurIP && dst_ip != 0xFFFFFFFF) {

  #ifdef CONFIG_MCAST_TFTP

  			if (Mcast_addr != dst_ip)

  #endif

  				return;

  		}

  		/* Read source IP address for later use */
  		src_ip = NetReadIP(&ip->ip_src);

  		/*

  		 * The function returns the unchanged packet if it's not
  		 * a fragment, and either the complete packet or NULL if
  		 * it is a fragment (if !CONFIG_IP_DEFRAG, it returns NULL)
  		 */

  		ip = NetDefragment(ip, &len);
  		if (!ip)

  			return;
  		/*

  		 * watch for ICMP host redirects
  		 *

  		 * There is no real handler code (yet). We just watch
  		 * for ICMP host redirect messages. In case anybody
  		 * sees these messages: please contact me
  		 * (wd@denx.de), or - even better - send me the
  		 * necessary fixes :-)

  		 *

  		 * Note: in all cases where I have seen this so far
  		 * it was a problem with the router configuration,
  		 * for instance when a router was configured in the
  		 * BOOTP reply, but the TFTP server was on the same
  		 * subnet. So this is probably a warning that your
  		 * configuration might be wrong. But I'm not really
  		 * sure if there aren't any other situations.

  		 *
  		 * Simon Glass <sjg@chromium.org>: We get an ICMP when
  		 * we send a tftp packet to a dead connection, or when
  		 * there is no server at the other end.

  		 */
  		if (ip->ip_p == IPPROTO_ICMP) {

  			receive_icmp(ip, len, src_ip, et);
  			return;

  		} else if (ip->ip_p != IPPROTO_UDP) {	/* Only UDP packets */
  			return;
  		}

  		debug_cond(DEBUG_DEV_PKT,
  			"received UDP (to=%pI4, from=%pI4, len=%d)
  ",
  			&dst_ip, &src_ip, len);

  #ifdef CONFIG_UDP_CHECKSUM
  		if (ip->udp_xsum != 0) {

  			ulong   xsum;

  			ushort *sumptr;
  			ushort  sumlen;
  
  			xsum  = ip->ip_p;
  			xsum += (ntohs(ip->udp_len));
  			xsum += (ntohl(ip->ip_src) >> 16) & 0x0000ffff;
  			xsum += (ntohl(ip->ip_src) >>  0) & 0x0000ffff;
  			xsum += (ntohl(ip->ip_dst) >> 16) & 0x0000ffff;
  			xsum += (ntohl(ip->ip_dst) >>  0) & 0x0000ffff;
  
  			sumlen = ntohs(ip->udp_len);
  			sumptr = (ushort *) &(ip->udp_src);
  
  			while (sumlen > 1) {

  				ushort sumdata;

  
  				sumdata = *sumptr++;
  				xsum += ntohs(sumdata);
  				sumlen -= 2;
  			}
  			if (sumlen > 0) {

  				ushort sumdata;

  
  				sumdata = *(unsigned char *) sumptr;

  				sumdata = (sumdata << 8) & 0xff00;

  				xsum += sumdata;
  			}
  			while ((xsum >> 16) != 0) {

  				xsum = (xsum & 0x0000ffff) +
  				       ((xsum >> 16) & 0x0000ffff);

  			}
  			if ((xsum != 0x00000000) && (xsum != 0x0000ffff)) {

  				printf(" UDP wrong checksum %08lx %08x
  ",
  					xsum, ntohs(ip->udp_xsum));

  				return;
  			}
  		}
  #endif

  #ifdef CONFIG_NETCONSOLE

  		nc_input_packet((uchar *)ip + IP_UDP_HDR_SIZE,

  					src_ip,

  					ntohs(ip->udp_dst),
  					ntohs(ip->udp_src),
  					ntohs(ip->udp_len) - UDP_HDR_SIZE);

  #endif

  		/*
  		 *	IP header OK.  Pass the packet to the current handler.
  		 */

  		(*udp_packet_handler)((uchar *)ip + IP_UDP_HDR_SIZE,
  				ntohs(ip->udp_dst),
  				src_ip,
  				ntohs(ip->udp_src),
  				ntohs(ip->udp_len) - UDP_HDR_SIZE);

  		break;
  	}
  }
  
  
  /**********************************************************************/

  static int net_check_prereq(enum proto_t protocol)

  {
  	switch (protocol) {

  		/* Fall through */

  #if defined(CONFIG_CMD_PING)

  	case PING:

  		if (NetPingIP == 0) {

  			puts("*** ERROR: ping address not given
  ");

  			return 1;

  		}
  		goto common;

  #endif

  #if defined(CONFIG_CMD_SNTP)

  	case SNTP:
  		if (NetNtpServerIP == 0) {

  			puts("*** ERROR: NTP server address not given
  ");

  			return 1;

  		}
  		goto common;
  #endif

  #if defined(CONFIG_CMD_DNS)
  	case DNS:
  		if (NetOurDNSIP == 0) {
  			puts("*** ERROR: DNS server address not given
  ");
  			return 1;
  		}
  		goto common;
  #endif

  #if defined(CONFIG_CMD_NFS)

  	case NFS:
  #endif

  	case TFTPGET:

  	case TFTPPUT:

  		if (NetServerIP == 0) {

  			puts("*** ERROR: `serverip' not set
  ");

  			return 1;

  		}

  #if	defined(CONFIG_CMD_PING) || defined(CONFIG_CMD_SNTP) || \
  	defined(CONFIG_CMD_DNS)
  common:

  #endif

  		/* Fall through */

  	case NETCONS:

  	case TFTPSRV:

  		if (NetOurIP == 0) {

  			puts("*** ERROR: `ipaddr' not set
  ");

  			return 1;

  		}
  		/* Fall through */

  #ifdef CONFIG_CMD_RARP

  	case RARP:

  #endif

  	case BOOTP:

  	case CDP:

  	case DHCP:

  	case LINKLOCAL:

  		if (memcmp(NetOurEther, "\0\0\0\0\0\0", 6) == 0) {

  			int num = eth_get_dev_index();

  			switch (num) {
  			case -1:

  				puts("*** ERROR: No ethernet found.
  ");

  				return 1;

  			case 0:

  				puts("*** ERROR: `ethaddr' not set
  ");

  				break;

  			default:

  				printf("*** ERROR: `eth%daddr' not set
  ",

  					num);
  				break;

  			}

  			NetStartAgain();

  			return 2;

  		}
  		/* Fall through */
  	default:

  		return 0;

  	}

  	return 0;		/* OK */

  }
  /**********************************************************************/
  
  int

  NetCksumOk(uchar *ptr, int len)

  {
  	return !((NetCksum(ptr, len) + 1) & 0xfffe);
  }
  
  
  unsigned

  NetCksum(uchar *ptr, int len)

  {
  	ulong	xsum;

  	ushort *p = (ushort *)ptr;

  
  	xsum = 0;
  	while (len-- > 0)

  		xsum += *p++;

  	xsum = (xsum & 0xffff) + (xsum >> 16);
  	xsum = (xsum & 0xffff) + (xsum >> 16);

  	return xsum & 0xffff;

  }

  int
  NetEthHdrSize(void)
  {
  	ushort myvlanid;

  	myvlanid = ntohs(NetOurVLAN);
  	if (myvlanid == (ushort)-1)
  		myvlanid = VLAN_NONE;

  	return ((myvlanid & VLAN_IDMASK) == VLAN_NONE) ? ETHER_HDR_SIZE :
  		VLAN_ETHER_HDR_SIZE;

  }
  
  int

  NetSetEther(uchar *xet, uchar * addr, uint prot)

  {

  	struct ethernet_hdr *et = (struct ethernet_hdr *)xet;

  	ushort myvlanid;
  
  	myvlanid = ntohs(NetOurVLAN);
  	if (myvlanid == (ushort)-1)
  		myvlanid = VLAN_NONE;

  	memcpy(et->et_dest, addr, 6);
  	memcpy(et->et_src, NetOurEther, 6);

  	if ((myvlanid & VLAN_IDMASK) == VLAN_NONE) {

  		et->et_protlen = htons(prot);

  		return ETHER_HDR_SIZE;
  	} else {

  		struct vlan_ethernet_hdr *vet =
  			(struct vlan_ethernet_hdr *)xet;

  		vet->vet_vlan_type = htons(PROT_VLAN);
  		vet->vet_tag = htons((0 << 5) | (myvlanid & VLAN_IDMASK));
  		vet->vet_type = htons(prot);
  		return VLAN_ETHER_HDR_SIZE;
  	}
  }

  int net_update_ether(struct ethernet_hdr *et, uchar *addr, uint prot)
  {
  	ushort protlen;
  
  	memcpy(et->et_dest, addr, 6);
  	memcpy(et->et_src, NetOurEther, 6);
  	protlen = ntohs(et->et_protlen);
  	if (protlen == PROT_VLAN) {
  		struct vlan_ethernet_hdr *vet =
  			(struct vlan_ethernet_hdr *)et;
  		vet->vet_type = htons(prot);
  		return VLAN_ETHER_HDR_SIZE;
  	} else if (protlen > 1514) {
  		et->et_protlen = htons(prot);
  		return ETHER_HDR_SIZE;
  	} else {
  		/* 802.2 + SNAP */
  		struct e802_hdr *et802 = (struct e802_hdr *)et;
  		et802->et_prot = htons(prot);
  		return E802_HDR_SIZE;
  	}
  }

  void net_set_ip_header(uchar *pkt, IPaddr_t dest, IPaddr_t source)

  {

  	struct ip_udp_hdr *ip = (struct ip_udp_hdr *)pkt;

  
  	/*

  	 *	Construct an IP header.

  	 */

  	/* IP_HDR_SIZE / 4 (not including UDP) */
  	ip->ip_hl_v  = 0x45;

  	ip->ip_tos   = 0;

  	ip->ip_len   = htons(IP_HDR_SIZE);

  	ip->ip_id    = htons(NetIPID++);

  	ip->ip_off   = htons(IP_FLAGS_DFRAG);	/* Don't fragment */

  	ip->ip_ttl   = 255;

  	ip->ip_sum   = 0;

  	/* already in network byte order */

  	NetCopyIP((void *)&ip->ip_src, &source);
  	/* already in network byte order */

  	NetCopyIP((void *)&ip->ip_dst, &dest);

  }
  
  void net_set_udp_header(uchar *pkt, IPaddr_t dest, int dport, int sport,
  			int len)
  {
  	struct ip_udp_hdr *ip = (struct ip_udp_hdr *)pkt;
  
  	/*
  	 *	If the data is an odd number of bytes, zero the
  	 *	byte after the last byte so that the checksum
  	 *	will work.
  	 */
  	if (len & 1)
  		pkt[IP_UDP_HDR_SIZE + len] = 0;
  
  	net_set_ip_header(pkt, dest, NetOurIP);
  	ip->ip_len   = htons(IP_UDP_HDR_SIZE + len);
  	ip->ip_p     = IPPROTO_UDP;
  	ip->ip_sum   = ~NetCksum((uchar *)ip, IP_HDR_SIZE >> 1);

  	ip->udp_src  = htons(sport);
  	ip->udp_dst  = htons(dport);

  	ip->udp_len  = htons(UDP_HDR_SIZE + len);

  	ip->udp_xsum = 0;

  }

  void copy_filename(char *dst, const char *src, int size)

  {
  	if (*src && (*src == '"')) {
  		++src;
  		--size;
  	}

  	while ((--size > 0) && *src && (*src != '"'))

  		*dst++ = *src++;

  	*dst = '\0';
  }

  #if	defined(CONFIG_CMD_NFS)		|| \
  	defined(CONFIG_CMD_SNTP)	|| \
  	defined(CONFIG_CMD_DNS)

  /*

   * make port a little random (1024-17407)
   * This keeps the math somewhat trivial to compute, and seems to work with
   * all supported protocols/clients/servers

   */
  unsigned int random_port(void)
  {

  	return 1024 + (get_timer(0) % 0x4000);

  }
  #endif

  void ip_to_string(IPaddr_t x, char *s)

  {

  	x = ntohl(x);
  	sprintf(s, "%d.%d.%d.%d",
  		(int) ((x >> 24) & 0xff),
  		(int) ((x >> 16) & 0xff),
  		(int) ((x >> 8) & 0xff), (int) ((x >> 0) & 0xff)

  	);

  }

  void VLAN_to_string(ushort x, char *s)
  {
  	x = ntohs(x);
  
  	if (x == (ushort)-1)
  		x = VLAN_NONE;
  
  	if (x == VLAN_NONE)
  		strcpy(s, "none");
  	else
  		sprintf(s, "%d", x & VLAN_IDMASK);
  }

  ushort string_to_VLAN(const char *s)

  {
  	ushort id;
  
  	if (s == NULL)

  		return htons(VLAN_NONE);

  
  	if (*s < '0' || *s > '9')
  		id = VLAN_NONE;
  	else
  		id = (ushort)simple_strtoul(s, NULL, 10);

  	return htons(id);

  }

  ushort getenv_VLAN(char *var)
  {

  	return string_to_VLAN(getenv(var));

  }