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  • 81091f58f0c58ecd26c5b05de2ae20ca6cdb521c
  • master default protected
  • early-display
  • variant-emmc-nvme-boot
  • 2023-01-25
  • v3
  • variant-emmc-nvme-boot
  • 2020-06-01
8 results

imx31_litekit.c

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    net.c 33.66 KiB
    /*
     *	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
     *	SPDX-License-Identifier:	GPL-2.0
     */
    
    /*
     * 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 <errno.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) */
    struct in_addr net_netmask;
    /* Our gateways IP address */
    struct in_addr net_gateway;
    /* Our DNS IP address */
    struct in_addr net_dns_server;
    #if defined(CONFIG_BOOTP_DNS2)
    /* Our 2nd DNS IP address */
    struct in_addr net_dns_server2;
    #endif
    
    #ifdef CONFIG_MCAST_TFTP	/* Multicast TFTP */
    struct in_addr net_mcast_addr;
    #endif
    
    /** END OF BOOTP EXTENTIONS **/
    
    /* Our ethernet address */
    u8 net_ethaddr[6];
    /* Boot server enet address */
    u8 net_server_ethaddr[6];
    /* Our IP addr (0 = unknown) */
    struct in_addr	net_ip;
    /* Server IP addr (0 = unknown) */
    struct in_addr	net_server_ip;
    /* Current receive packet */
    uchar *net_rx_packet;
    /* Current rx packet length */
    int		net_rx_packet_len;
    /* IP packet ID */
    unsigned	NetIPID;
    /* Ethernet bcast address */
    const u8 net_bcast_ethaddr[6] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
    const u8 net_null_ethaddr[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		net_our_vlan = 0xFFFF;
    /* ditto */
    ushort		net_native_vlan = 0xFFFF;
    
    /* Boot File name */
    char net_boot_file_name[128];
    /* The actual transferred size of the bootfile (in bytes) */
    u32 net_boot_file_size;
    /* Boot file size in blocks as reported by the DHCP server */
    u32 net_boot_file_expected_size_in_blocks;
    
    #if defined(CONFIG_CMD_SNTP)
    /* NTP server IP address */
    struct in_addr	net_ntp_server;
    /* offset time from UTC */
    int		NetTimeOffset;
    #endif
    
    static uchar net_pkt_buf[(PKTBUFSRX+1) * PKTSIZE_ALIGN + PKTALIGN];
    /* Receive packets */
    uchar *net_rx_packets[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 *net_tx_packet;
    
    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(net_boot_file_name, value,
    			      sizeof(net_boot_file_name));
    		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.
    		 */
    		nfs_start();
    		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;
    	}
    	tftp_start(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) {
    		net_ip = getenv_ip("ipaddr");
    		net_gateway = getenv_ip("gatewayip");
    		net_netmask = getenv_ip("netmask");
    		net_server_ip = getenv_ip("serverip");
    		net_native_vlan = getenv_vlan("nvlan");
    		net_our_vlan = getenv_vlan("vlan");
    #if defined(CONFIG_CMD_DNS)
    		net_dns_server = getenv_ip("dnsip");
    #endif
    		env_changed_id = env_id;
    	}
    	if (eth_get_dev())
    		memcpy(net_ethaddr, eth_get_ethaddr(), 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;
    
    		net_tx_packet = &net_pkt_buf[0] + (PKTALIGN - 1);
    		net_tx_packet -= (ulong)net_tx_packet % PKTALIGN;
    		for (i = 0; i < PKTBUFSRX; i++) {
    			net_rx_packets[i] = net_tx_packet +
    				(i + 1) * PKTSIZE_ALIGN;
    		}
    		arp_init();
    		net_clear_handlers();
    
    		/* Only need to setup buffer pointers once. */
    		first_call = 0;
    	}
    
    	NetInitLoop();
    }
    
    /**********************************************************************/
    /*
     *	Main network processing loop.
     */
    
    int NetLoop(enum proto_t protocol)
    {
    	int ret = -EINVAL;
    
    	NetRestarted = 0;
    	NetDevExists = 0;
    	NetTryCount = 1;
    	debug_cond(DEBUG_INT_STATE, "--- NetLoop Entry\n");
    
    	bootstage_mark_name(BOOTSTAGE_ID_ETH_START, "eth_start");
    	net_init();
    	if (eth_is_on_demand_init() || protocol != NETCONS) {
    		eth_halt();
    		eth_set_current();
    		ret = eth_init();
    		if (ret < 0) {
    			eth_halt();
    			return ret;
    		}
    	} else
    		eth_init_state_only();
    
    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\n");
    	NetInitLoop();
    
    	switch (net_check_prereq(protocol)) {
    	case 1:
    		/* network not configured */
    		eth_halt();
    		return -ENODEV;
    
    	case 2:
    		/* network device not configured */
    		break;
    
    	case 0:
    		NetDevExists = 1;
    		net_boot_file_size = 0;
    		switch (protocol) {
    		case TFTPGET:
    #ifdef CONFIG_CMD_TFTPPUT
    		case TFTPPUT:
    #endif
    			/* always use ARP to get server ethernet address */
    			tftp_start(protocol);
    			break;
    #ifdef CONFIG_CMD_TFTPSRV
    		case TFTPSRV:
    			tftp_start_server();
    			break;
    #endif
    #if defined(CONFIG_CMD_DHCP)
    		case DHCP:
    			bootp_reset();
    			net_ip.s_addr = 0;
    			dhcp_request();		/* Basically same as BOOTP */
    			break;
    #endif
    
    		case BOOTP:
    			bootp_reset();
    			net_ip.s_addr = 0;
    			bootp_request();
    			break;
    
    #if defined(CONFIG_CMD_RARP)
    		case RARP:
    			rarp_try = 0;
    			net_ip.s_addr = 0;
    			rarp_request();
    			break;
    #endif
    #if defined(CONFIG_CMD_PING)
    		case PING:
    			ping_start();
    			break;
    #endif
    #if defined(CONFIG_CMD_NFS)
    		case NFS:
    			nfs_start();
    			break;
    #endif
    #if defined(CONFIG_CMD_CDP)
    		case CDP:
    			cdp_start();
    			break;
    #endif
    #if defined (CONFIG_NETCONSOLE) && !(CONFIG_SPL_BUILD)
    		case NETCONS:
    			nc_start();
    			break;
    #endif
    #if defined(CONFIG_CMD_SNTP)
    		case SNTP:
    			sntp_start();
    			break;
    #endif
    #if defined(CONFIG_CMD_DNS)
    		case DNS:
    			dns_start();
    			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.
    		 *	Most drivers return the most recent packet size, but not
    		 *	errors that may have happened.
    		 */
    		eth_rx();
    
    		/*
    		 *	Abort if ctrl-c was pressed.
    		 */
    		if (ctrlc()) {
    			/* cancel any ARP that may not have completed */
    			net_arp_wait_packet_ip.s_addr = 0;
    
    			net_cleanup_loop();
    			eth_halt();
    			/* Invalidate the last protocol */
    			eth_set_last_protocol(BOOTP);
    
    			puts("\nAbort\n");
    			/* include a debug print as well incase the debug
    			   messages are directed to stderr */
    			debug_cond(DEBUG_INT_STATE, "--- NetLoop Abort!\n");
    			goto done;
    		}
    
    		arp_timeout_check();
    
    		/*
    		 *	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\n");
    			x = timeHandler;
    			timeHandler = (thand_f *)0;
    			(*x)();
    		}
    
    		if (net_state == NETLOOP_FAIL)
    			ret = NetStartAgain();
    
    		switch (net_state) {
    
    		case NETLOOP_RESTART:
    			NetRestarted = 1;
    			goto restart;
    
    		case NETLOOP_SUCCESS:
    			net_cleanup_loop();
    			if (net_boot_file_size > 0) {
    				printf("Bytes transferred = %d (%x hex)\n",
    				       net_boot_file_size, net_boot_file_size);
    				setenv_hex("filesize", net_boot_file_size);
    				setenv_hex("fileaddr", load_addr);
    			}
    			if (protocol != NETCONS)
    				eth_halt();
    			else
    				eth_halt_state_only();
    
    			eth_set_last_protocol(protocol);
    
    			ret = net_boot_file_size;
    			debug_cond(DEBUG_INT_STATE, "--- NetLoop Success!\n");
    			goto done;
    
    		case NETLOOP_FAIL:
    			net_cleanup_loop();
    			/* Invalidate the last protocol */
    			eth_set_last_protocol(BOOTP);
    			debug_cond(DEBUG_INT_STATE, "--- NetLoop Fail!\n");
    			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);
    }
    
    int NetStartAgain(void)
    {
    	char *nretry;
    	int retry_forever = 0;
    	unsigned long retrycnt = 0;
    	int ret;
    
    	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 {
    		retrycnt = 0;
    		retry_forever = 0;
    	}
    
    	if ((!retry_forever) && (NetTryCount >= retrycnt)) {
    		eth_halt();
    		net_set_state(NETLOOP_FAIL);
    		/*
    		 * We don't provide a way for the protocol to return an error,
    		 * but this is almost always the reason.
    		 */
    		return -ETIMEDOUT;
    	}
    
    	NetTryCount++;
    
    	eth_halt();
    #if !defined(CONFIG_NET_DO_NOT_TRY_ANOTHER)
    	eth_try_another(!NetRestarted);
    #endif
    	ret = eth_init();
    	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);
    	}
    	return ret;
    }
    
    /**********************************************************************/
    /*
     *	Miscelaneous bits.
     */
    
    static void dummy_handler(uchar *pkt, unsigned dport,
    			struct in_addr 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)\n", 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)\n", 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\n");
    		timeHandler = (thand_f *)0;
    	} else {
    		debug_cond(DEBUG_INT_STATE,
    			"--- NetLoop timeout handler set (%p)\n", f);
    		timeHandler = f;
    		timeStart = get_timer(0);
    		timeDelta = iv * CONFIG_SYS_HZ / 1000;
    	}
    }
    
    int net_send_udp_packet(uchar *ether, struct in_addr dest, int dport, int sport,
    		int payload_len)
    {
    	uchar *pkt;
    	int eth_hdr_size;
    	int pkt_hdr_size;
    
    	/* make sure the net_tx_packet is initialized (NetInit() was called) */
    	assert(net_tx_packet != NULL);
    	if (net_tx_packet == NULL)
    		return -1;
    
    	/* convert to new style broadcast */
    	if (dest.s_addr == 0)
    		dest.s_addr = 0xFFFFFFFF;
    
    	/* if broadcast, make the ether address a broadcast and don't do ARP */
    	if (dest.s_addr == 0xFFFFFFFF)
    		ether = (uchar *)net_bcast_ethaddr;
    
    	pkt = (uchar *)net_tx_packet;
    
    	eth_hdr_size = net_set_ether(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, net_null_ethaddr, 6) == 0) {
    		debug_cond(DEBUG_DEV_PKT, "sending ARP for %pI4\n", &dest);
    
    		/* save the ip and eth addr for the packet to send after arp */
    		net_arp_wait_packet_ip = dest;
    		arp_wait_packet_ethaddr = ether;
    
    		/* size of the waiting packet */
    		arp_wait_tx_packet_size = pkt_hdr_size + payload_len;
    
    		/* and do the ARP request */
    		arp_wait_try = 1;
    		arp_wait_timer_start = get_timer(0);
    		arp_request();
    		return 1;	/* waiting */
    	} else {
    		debug_cond(DEBUG_DEV_PKT, "sending UDP to %pI4/%pM\n",
    			&dest, ether);
    		net_send_packet(net_tx_packet, 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,
    			struct in_addr 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 net_process_received_packet(uchar *in_packet, int len)
    {
    	struct ethernet_hdr *et;
    	struct ip_udp_hdr *ip;
    	struct in_addr dst_ip;
    	struct in_addr 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\n");
    
    	net_rx_packet = in_packet;
    	net_rx_packet_len = len;
    	et = (struct ethernet_hdr *)in_packet;
    
    	/* too small packet? */
    	if (len < ETHER_HDR_SIZE)
    		return;
    
    #ifdef CONFIG_API
    	if (push_packet) {
    		(*push_packet)(in_packet, len);
    		return;
    	}
    #endif
    
    #if defined(CONFIG_CMD_CDP)
    	/* keep track if packet is CDP */
    	iscdp = is_cdp_packet(et->et_dest);
    #endif
    
    	myvlanid = ntohs(net_our_vlan);
    	if (myvlanid == (ushort)-1)
    		myvlanid = VLAN_NONE;
    	mynvlanid = ntohs(net_native_vlan);
    	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 *)(in_packet + E802_HDR_SIZE);
    		len -= E802_HDR_SIZE;
    
    	} else if (eth_proto != PROT_VLAN) {	/* normal packet */
    		ip = (struct ip_udp_hdr *)(in_packet + 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\n");
    
    		/* too small packet? */
    		if (len < VLAN_ETHER_HDR_SIZE)
    			return;
    
    		/* if no VLAN active */
    		if ((ntohs(net_our_vlan) & 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 *)(in_packet + VLAN_ETHER_HDR_SIZE);
    		len -= VLAN_ETHER_HDR_SIZE;
    	}
    
    	debug_cond(DEBUG_NET_PKT, "Receive from protocol 0x%x\n", 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:
    		arp_receive(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\n");
    		/* Before we start poking the header, make sure it is there */
    		if (len < IP_UDP_HDR_SIZE) {
    			debug("len bad %d < %lu\n", len,
    				(ulong)IP_UDP_HDR_SIZE);
    			return;
    		}
    		/* Check the packet length */
    		if (len < ntohs(ip->ip_len)) {
    			debug("len bad %d < %d\n", len, ntohs(ip->ip_len));
    			return;
    		}
    		len = ntohs(ip->ip_len);
    		debug_cond(DEBUG_NET_PKT, "len=%d, v=%02x\n",
    			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 (!ip_checksum_ok((uchar *)ip, IP_HDR_SIZE)) {
    			debug("checksum bad\n");
    			return;
    		}
    		/* If it is not for us, ignore it */
    		dst_ip = net_read_ip(&ip->ip_dst);
    		if (net_ip.s_addr && dst_ip.s_addr != net_ip.s_addr &&
    		    dst_ip.s_addr != 0xFFFFFFFF) {
    #ifdef CONFIG_MCAST_TFTP
    			if (net_mcast_addr != dst_ip)
    #endif
    				return;
    		}
    		/* Read source IP address for later use */
    		src_ip = net_read_ip(&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)\n",
    			&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.s_addr) >> 16) & 0x0000ffff;
    			xsum += (ntohl(ip->ip_src.s_addr) >>  0) & 0x0000ffff;
    			xsum += (ntohl(ip->ip_dst.s_addr) >> 16) & 0x0000ffff;
    			xsum += (ntohl(ip->ip_dst.s_addr) >>  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\n",
    					xsum, ntohs(ip->udp_xsum));
    				return;
    			}
    		}
    #endif
    
    
    #if defined (CONFIG_NETCONSOLE) && !(CONFIG_SPL_BUILD)
    		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 (net_ping_ip.s_addr == 0) {
    			puts("*** ERROR: ping address not given\n");
    			return 1;
    		}
    		goto common;
    #endif
    #if defined(CONFIG_CMD_SNTP)
    	case SNTP:
    		if (net_ntp_server.s_addr == 0) {
    			puts("*** ERROR: NTP server address not given\n");
    			return 1;
    		}
    		goto common;
    #endif
    #if defined(CONFIG_CMD_DNS)
    	case DNS:
    		if (net_dns_server.s_addr == 0) {
    			puts("*** ERROR: DNS server address not given\n");
    			return 1;
    		}
    		goto common;
    #endif
    #if defined(CONFIG_CMD_NFS)
    	case NFS:
    #endif
    	case TFTPGET:
    	case TFTPPUT:
    		if (net_server_ip.s_addr == 0) {
    			puts("*** ERROR: `serverip' not set\n");
    			return 1;
    		}
    #if	defined(CONFIG_CMD_PING) || defined(CONFIG_CMD_SNTP) || \
    	defined(CONFIG_CMD_DNS)
    common:
    #endif
    		/* Fall through */
    
    	case NETCONS:
    	case TFTPSRV:
    		if (net_ip.s_addr == 0) {
    			puts("*** ERROR: `ipaddr' not set\n");
    			return 1;
    		}
    		/* Fall through */
    
    #ifdef CONFIG_CMD_RARP
    	case RARP:
    #endif
    	case BOOTP:
    	case CDP:
    	case DHCP:
    	case LINKLOCAL:
    		if (memcmp(net_ethaddr, "\0\0\0\0\0\0", 6) == 0) {
    			int num = eth_get_dev_index();
    
    			switch (num) {
    			case -1:
    				puts("*** ERROR: No ethernet found.\n");
    				return 1;
    			case 0:
    				puts("*** ERROR: `ethaddr' not set\n");
    				break;
    			default:
    				printf("*** ERROR: `eth%daddr' not set\n",
    					num);
    				break;
    			}
    
    			NetStartAgain();
    			return 2;
    		}
    		/* Fall through */
    	default:
    		return 0;
    	}
    	return 0;		/* OK */
    }
    /**********************************************************************/
    
    int
    net_eth_hdr_size(void)
    {
    	ushort myvlanid;
    
    	myvlanid = ntohs(net_our_vlan);
    	if (myvlanid == (ushort)-1)
    		myvlanid = VLAN_NONE;
    
    	return ((myvlanid & VLAN_IDMASK) == VLAN_NONE) ? ETHER_HDR_SIZE :
    		VLAN_ETHER_HDR_SIZE;
    }
    
    int net_set_ether(uchar *xet, const uchar *dest_ethaddr, uint prot)
    {
    	struct ethernet_hdr *et = (struct ethernet_hdr *)xet;
    	ushort myvlanid;
    
    	myvlanid = ntohs(net_our_vlan);
    	if (myvlanid == (ushort)-1)
    		myvlanid = VLAN_NONE;
    
    	memcpy(et->et_dest, dest_ethaddr, 6);
    	memcpy(et->et_src, net_ethaddr, 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, net_ethaddr, 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, struct in_addr dest, struct in_addr 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 */
    	net_copy_ip((void *)&ip->ip_src, &source);
    	/* already in network byte order */
    	net_copy_ip((void *)&ip->ip_dst, &dest);
    }
    
    void net_set_udp_header(uchar *pkt, struct in_addr 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, net_ip);
    	ip->ip_len   = htons(IP_UDP_HDR_SIZE + len);
    	ip->ip_p     = IPPROTO_UDP;
    	ip->ip_sum   = compute_ip_checksum(ip, IP_HDR_SIZE);
    
    	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(struct in_addr x, char *s)
    {
    	x.s_addr = ntohl(x.s_addr);
    	sprintf(s, "%d.%d.%d.%d",
    		(int) ((x.s_addr >> 24) & 0xff),
    		(int) ((x.s_addr >> 16) & 0xff),
    		(int) ((x.s_addr >> 8) & 0xff),
    		(int) ((x.s_addr >> 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));
    }