/*
 *      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 <console.h>
#include <environment.h>
#include <errno.h>
#include <net.h>
#include <net/tftp.h>
#if defined(CONFIG_LED_STATUS)
#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

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 */
static unsigned net_ip_id;
/* Ethernet bcast address */
const u8 net_bcast_ethaddr[6] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
const u8 net_null_ethaddr[6];
#if defined(CONFIG_API) || defined(CONFIG_EFI_LOADER)
void (*push_packet)(void *, int len) = 0;
#endif
/* Network loop state */
enum net_loop_state net_state;
/* Tried all network devices */
int             net_restart_wrap;
/* Network loop restarted */
static int      net_restarted;
/* At least one device configured */
static int      net_dev_exists;

/* 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[1024];
/* 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             net_ntp_time_offset;
#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 *time_handler;
/* Time base value */
static ulong    time_start;
/* Current timeout value */
static ulong    time_delta;
/* THE transmit packet */
uchar *net_tx_packet;

static int net_check_prereq(enum proto_t protocol);

static int net_try_count;

int __maybe_unused net_busy_flag;

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

static int on_bootfile(const char *name, const char *value, enum env_op op,
        int flags)
{
        if (flags & H_PROGRAMMATIC)
                return 0;

        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);

static int on_ipaddr(const char *name, const char *value, enum env_op op,
        int flags)
{
        if (flags & H_PROGRAMMATIC)
                return 0;

        net_ip = string_to_ip(value);

        return 0;
}
U_BOOT_ENV_CALLBACK(ipaddr, on_ipaddr);

static int on_gatewayip(const char *name, const char *value, enum env_op op,
        int flags)
{
        if (flags & H_PROGRAMMATIC)
                return 0;

        net_gateway = string_to_ip(value);

        return 0;
}
U_BOOT_ENV_CALLBACK(gatewayip, on_gatewayip);

static int on_netmask(const char *name, const char *value, enum env_op op,
        int flags)
{
        if (flags & H_PROGRAMMATIC)
                return 0;

        net_netmask = string_to_ip(value);

        return 0;
}
U_BOOT_ENV_CALLBACK(netmask, on_netmask);

static int on_serverip(const char *name, const char *value, enum env_op op,
        int flags)
{
        if (flags & H_PROGRAMMATIC)
                return 0;

        net_server_ip = string_to_ip(value);

        return 0;
}
U_BOOT_ENV_CALLBACK(serverip, on_serverip);

static int on_nvlan(const char *name, const char *value, enum env_op op,
        int flags)
{
        if (flags & H_PROGRAMMATIC)
                return 0;

        net_native_vlan = string_to_vlan(value);

        return 0;
}
U_BOOT_ENV_CALLBACK(nvlan, on_nvlan);

static int on_vlan(const char *name, const char *value, enum env_op op,
        int flags)
{
        if (flags & H_PROGRAMMATIC)
                return 0;

        net_our_vlan = string_to_vlan(value);

        return 0;
}
U_BOOT_ENV_CALLBACK(vlan, on_vlan);

#if defined(CONFIG_CMD_DNS)
static int on_dnsip(const char *name, const char *value, enum env_op op,
        int flags)
{
        if (flags & H_PROGRAMMATIC)
                return 0;

        net_dns_server = string_to_ip(value);

        return 0;
}
U_BOOT_ENV_CALLBACK(dnsip, on_dnsip);
#endif

/*
 * 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 = env_get("autoload");

        if (s != NULL && strcmp(s, "NFS") == 0) {
                /*
                 * Use NFS to load the bootfile.
                 */
                nfs_start();
                return;
        }
#endif
        if (env_get_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 net_init_loop(void)
{
        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);
        net_set_timeout_handler(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;
        }

        net_init_loop();
}

/**********************************************************************/
/*
 *      Main network processing loop.
 */

int net_loop(enum proto_t protocol)
{
        int ret = -EINVAL;

        net_restarted = 0;
        net_dev_exists = 0;
        net_try_count = 1;
        debug_cond(DEBUG_INT_STATE, "--- net_loop 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, "--- net_loop Init\n");
        net_init_loop();

        switch (net_check_prereq(protocol)) {
        case 1:
                /* network not configured */
                eth_halt();
                return -ENODEV;

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

        case 0:
                net_dev_exists = 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) && !defined(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_LED_STATUS)                      && \
        defined(CONFIG_LED_STATUS_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(CONFIG_LED_STATUS_RED, CONFIG_LED_STATUS_OFF);
        else
                status_led_set(CONFIG_LED_STATUS_RED, CONFIG_LED_STATUS_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
                if (arp_timeout_check() > 0)
                        time_start = get_timer(0);

                /*
                 *      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, "--- net_loop Abort!\n");
                        ret = -EINTR;
                        goto done;
                }

                /*
                 *      Check for a timeout, and run the timeout handler
                 *      if we have one.
                 */
                if (time_handler &&
                    ((get_timer(0) - time_start) > time_delta)) {
                        thand_f *x;

#if defined(CONFIG_MII) || defined(CONFIG_CMD_MII)
#if     defined(CONFIG_SYS_FAULT_ECHO_LINK_DOWN)        && \
        defined(CONFIG_LED_STATUS)                      && \
        defined(CONFIG_LED_STATUS_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(CONFIG_LED_STATUS_RED,
                                               CONFIG_LED_STATUS_OFF);
                        else
                                status_led_set(CONFIG_LED_STATUS_RED,
                                               CONFIG_LED_STATUS_ON);
#endif /* CONFIG_SYS_FAULT_ECHO_LINK_DOWN, ... */
#endif /* CONFIG_MII, ... */
                        debug_cond(DEBUG_INT_STATE, "--- net_loop timeout\n");
                        x = time_handler;
                        time_handler = (thand_f *)0;
                        (*x)();
                }

                if (net_state == NETLOOP_FAIL)
                        ret = net_start_again();

                switch (net_state) {
                case NETLOOP_RESTART:
                        net_restarted = 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);
                                env_set_hex("filesize", net_boot_file_size);
                                env_set_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, "--- net_loop Success!\n");
                        goto done;

                case NETLOOP_FAIL:
                        net_cleanup_loop();
                        /* Invalidate the last protocol */
                        eth_set_last_protocol(BOOTP);
                        debug_cond(DEBUG_INT_STATE, "--- net_loop 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 start_again_timeout_handler(void)
{
        net_set_state(NETLOOP_RESTART);
}

int net_start_again(void)
{
        char *nretry;
        int retry_forever = 0;
        unsigned long retrycnt = 0;
        int ret;

        nretry = env_get("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) && (net_try_count >= 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;
        }

        net_try_count++;

        eth_halt();
#if !defined(CONFIG_NET_DO_NOT_TRY_ANOTHER)
        eth_try_another(!net_restarted);
#endif
        ret = eth_init();
        if (net_restart_wrap) {
                net_restart_wrap = 0;
                if (net_dev_exists) {
                        net_set_timeout_handler(10000UL,
                                                start_again_timeout_handler);
                        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, "--- net_loop 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, "--- net_loop 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 net_set_timeout_handler(ulong iv, thand_f *f)
{
        if (iv == 0) {
                debug_cond(DEBUG_INT_STATE,
                           "--- net_loop timeout handler cancelled\n");
                time_handler = (thand_f *)0;
        } else {
                debug_cond(DEBUG_INT_STATE,
                           "--- net_loop timeout handler set (%p)\n", f);
                time_handler = f;
                time_start = get_timer(0);
                time_delta = 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 (net_init() 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
#define IP_PKTSIZE (CONFIG_NET_MAXDEFRAG)

#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 *__net_defragment(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 *net_defragment(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 __net_defragment(ip, lenp);
}

#else /* !CONFIG_IP_DEFRAG */

static inline struct ip_udp_hdr *net_defragment(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;

#if defined(CONFIG_API) || defined(CONFIG_EFI_LOADER)
        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 = net_defragment(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) && !defined(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
                /* Fall through */
        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;
                        }

                        net_start_again();
                        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(net_ip_id++);
        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 env_get_vlan(char *var)
{
        return string_to_vlan(env_get(var));
}