source: rtems/c/src/lib/libnetworking/lib/tftpDriver.c @ 39e6e65a

/*
 * Trivial File Transfer Protocol (RFC 1350)
 *
 * Transfer file to/from remote host
 *
 * W. Eric Norum
 * Saskatchewan Accelerator Laboratory
 * University of Saskatchewan
 * Saskatoon, Saskatchewan, CANADA
 * eric@skatter.usask.ca
 *
 *  $Id$
 */

#include <stdio.h>
#include <errno.h>
#include <malloc.h>
#include <string.h>
#include <unistd.h>
#include <rtems.h>
#include <rtems/libio.h>
#include <rtems/rtems_bsdnet.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

/*
 * Range of UDP ports to try
 */
#define UDP_PORT_BASE   3180

/*
 * Pathname prefix
 */
#define TFTP_PATHNAME_PREFIX    "/TFTP/"

/*
 * Default limits
 */
#define PACKET_REPLY_MILLISECONDS       6000
#define OPEN_RETRY_LIMIT        10
#define IO_RETRY_LIMIT          10

/*
 * TFTP opcodes
 */
#define TFTP_OPCODE_RRQ         1
#define TFTP_OPCODE_WRQ         2
#define TFTP_OPCODE_DATA        3
#define TFTP_OPCODE_ACK         4
#define TFTP_OPCODE_ERROR       5

/*
 * Largest data transfer
 */
#define TFTP_BUFSIZE    512

/*
 * Packets transferred between machines
 */
union tftpPacket {
        /*
         * RRQ/WRQ packet
         */
        struct tftpRWRQ {
                rtems_unsigned16        opcode;
                char                    filename_mode[TFTP_BUFSIZE];
        } tftpRWRQ;

        /*
         * DATA packet
         */
        struct tftpDATA {
                rtems_unsigned16        opcode;
                rtems_unsigned16        blocknum;
                rtems_unsigned8         data[TFTP_BUFSIZE];
        } tftpDATA;

        /*
         * ACK packet
         */
        struct tftpACK {
                rtems_unsigned16        opcode;
                rtems_unsigned16        blocknum;
        } tftpACK;

        /*
         * ERROR packet
         */
        struct tftpERROR {
                rtems_unsigned16        opcode;
                rtems_unsigned16        errorCode;
                char                    errorMessage[TFTP_BUFSIZE];
        } tftpERROR;
};

/*
 * State of each TFTP stream
 */
struct tftpStream {
        /*
         * Buffer for storing most recently-received packet
         */
        union tftpPacket        pkbuf;

        /*
         * Last block number received
         */
        rtems_unsigned16        blocknum;

        /*
         * Data transfer socket
         */
        int                     socket;
        struct sockaddr_in      myAddress;
        struct sockaddr_in      farAddress;

        /*
         * Indices into buffer
         */
        int     nleft;
        int     nused;

        /*
         * Flags
         */
        int     firstReply;
        int     eof;
};

/*
 * Number of streams open at the same time
 */
static rtems_id tftp_mutex;
static int nStreams;
static struct tftpStream ** volatile tftpStreams;

/*
 * Initialize the TFTP driver
 */
rtems_device_driver rtems_tftp_initialize(
  rtems_device_major_number major,
  rtems_device_minor_number minor,
  void *pargp
)
{
        rtems_status_code sc;

        sc = rtems_semaphore_create (rtems_build_name('T', 'F', 'T', 'P'),
                                        1,
                                        RTEMS_FIFO |
                                                RTEMS_BINARY_SEMAPHORE |
                                                RTEMS_NO_INHERIT_PRIORITY |
                                                RTEMS_NO_PRIORITY_CEILING |
                                                RTEMS_LOCAL,
                                        0,
                                        &tftp_mutex);
        if (sc != RTEMS_SUCCESSFUL)
                return sc;
        rtems_io_register_name (TFTP_PATHNAME_PREFIX, major, minor);
        return RTEMS_SUCCESSFUL;
}

/*
 * Set error message
 * This RTEMS/UNIX error mapping needs to be fixed!
 */
static void
tftpSetErrno (struct tftpStream *tp)
{
        unsigned int tftpError;
        static const int errorMap[] = {
                0,
                ENOENT,
                EPERM,
                ENOSPC,
                EINVAL,
                ENXIO,
                EEXIST,
                ESRCH,
                0,
        };

        tftpError = ntohs (tp->pkbuf.tftpERROR.errorCode);
        if (tftpError < (sizeof errorMap / sizeof errorMap[0]))
                errno = errorMap[tftpError];
        else
                errno = 1000 + tftpError;
}

/*
 * Send a message to make the other end shut up
 */
static void
sendStifle (struct tftpStream *tp, struct sockaddr_in *to)
{
        int len;

        /*
         * Create the error packet (Unknown transfer ID).
         */
        tp->pkbuf.tftpERROR.opcode = htons (TFTP_OPCODE_ERROR);
        tp->pkbuf.tftpERROR.errorCode = htons (5);
        len = sizeof tp->pkbuf.tftpERROR.opcode +
                                sizeof tp->pkbuf.tftpERROR.errorCode + 1;
        len += sprintf (tp->pkbuf.tftpERROR.errorMessage, "GO AWAY"); 

        /*
         * Send it
         */
        sendto (tp->socket, (char *)&tp->pkbuf, len, 0,
                                        (struct sockaddr *)to, sizeof *to);
}

/*
 * Wait for a data packet
 */
static int
getPacket (struct tftpStream *tp)
{
        int len;
        struct timeval tv;

        tv.tv_sec = 6;
        tv.tv_usec = 0;
        setsockopt (tp->socket, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof tv);
        for (;;) {
                union {
                        struct sockaddr s;
                        struct sockaddr_in i;
                } from;
                int fromlen = sizeof from;
                len = recvfrom (tp->socket, (char *)&tp->pkbuf,
                                                        sizeof tp->pkbuf, 0,
                                                        &from.s, &fromlen);
                if (len < 0)
                        break;
                if (from.i.sin_addr.s_addr == tp->farAddress.sin_addr.s_addr) {
                        if (tp->firstReply) {
                                tp->firstReply = 0;
                                tp->farAddress.sin_port = from.i.sin_port;
                        }
                        if (tp->farAddress.sin_port == from.i.sin_port) 
                                break;
                }

                /*
                 * Packet is from someone with whom we are
                 * not interested.  Tell them to go away.
                 */
                sendStifle (tp, &from.i);
        }
        tv.tv_sec = 0;
        setsockopt (tp->socket, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof tv);
        return len;
}

/*
 * Send an acknowledgement
 */
static int
sendAck (struct tftpStream *tp)
{
        /*
         * Create the acknowledgement
         */
        tp->pkbuf.tftpACK.opcode = htons (TFTP_OPCODE_ACK);
        tp->pkbuf.tftpACK.blocknum = htons (tp->blocknum);

        /*
         * Send it
         */
        if (sendto (tp->socket, (char *)&tp->pkbuf, sizeof tp->pkbuf.tftpACK, 0,
                                        (struct sockaddr *)&tp->farAddress,
                                        sizeof tp->farAddress) < 0)
                return errno;
        return 0;
}

/*
 * Release a stream and clear the pointer to it
 */
static void
releaseStream (int s)
{
        rtems_semaphore_obtain (tftp_mutex, RTEMS_WAIT, RTEMS_NO_TIMEOUT);
        free (tftpStreams[s]);
        tftpStreams[s] = NULL;
        rtems_semaphore_release (tftp_mutex);
}

/*
 * Open a TFTP stream
 */
rtems_device_driver rtems_tftp_open(
  rtems_device_major_number major,
  rtems_device_minor_number minor,
  void *pargp
)
{
        rtems_libio_open_close_args_t *ap = pargp;
        struct tftpStream *tp;
        int retryCount;
        rtems_unsigned32 farAddress;
        int s;
        int len;
        char *cp1, *cp2;
        char *remoteFilename;
        rtems_interval now;
        rtems_status_code sc;

        /*
         * Read-only for now
         */
        if (ap->flags & LIBIO_FLAGS_WRITE)
                return RTEMS_NOT_IMPLEMENTED;

        /*
         * Pick apart the name into a host:pathname pair
         */
        if (strlen (ap->iop->pathname) <= strlen (TFTP_PATHNAME_PREFIX))
                return RTEMS_INVALID_NAME;
        cp2 = ap->iop->pathname + strlen (TFTP_PATHNAME_PREFIX);
        if (*cp2 == '/') {
                farAddress = rtems_bsdnet_bootp_server_address.s_addr;
        }
        else {
                char *hostname;

                cp1 = cp2;
                while (*cp2 != '/') {
                        if (*cp2 == '\0')
                                return RTEMS_INVALID_NAME;
                        cp2++;
                }
                len = cp2 - cp1;
                hostname = malloc (len + 1);
                if (hostname == NULL)
                        return RTEMS_NO_MEMORY;
                strncpy (hostname, cp1, len);
                hostname[len] = '\0';
                farAddress = inet_addr (hostname);
                free (hostname);
        }
        if ((farAddress == 0) || (farAddress == ~0))
                return RTEMS_INVALID_NAME;
        if (*++cp2 == '\0')
                return RTEMS_INVALID_NAME;
        remoteFilename = cp2;
        if (strlen (remoteFilename) > (TFTP_BUFSIZE - 10))
                return RTEMS_INVALID_NAME;

        /*
         * Find a free stream
         */
        sc = rtems_semaphore_obtain (tftp_mutex, RTEMS_WAIT, RTEMS_NO_TIMEOUT);
        if (sc != RTEMS_SUCCESSFUL)
                return sc;
        for (s = 0 ; s < nStreams ; s++) {
                if (tftpStreams[s] == NULL)
                        break;
        }
        if (s == nStreams) {
                /*
                 * Reallocate stream pointers
                 * Guard against the case where realloc() returns NULL.
                 */
                struct tftpStream **np;

                np = realloc (tftpStreams, ++nStreams * sizeof *tftpStreams);
                if (np == NULL) {
                        rtems_semaphore_release (tftp_mutex);
                        return RTEMS_NO_MEMORY;
                }
                tftpStreams = np;
        }
        tp = tftpStreams[s] = malloc (sizeof (struct tftpStream));
        rtems_semaphore_release (tftp_mutex);
        if (tp == NULL)
                return RTEMS_NO_MEMORY;
        ap->iop->data0 = s;
        ap->iop->data1 = tp;

        /*
         * Create the socket
         */
        if ((tp->socket = socket (AF_INET, SOCK_DGRAM, 0)) < 0) {
                releaseStream (s);
                return RTEMS_TOO_MANY;
        }

        /*
         * Bind the socket to a local address
         */
        retryCount = 0;
        rtems_clock_get (RTEMS_CLOCK_GET_TICKS_SINCE_BOOT, &now);
        for (;;) {
                int try = (now + retryCount) % 10;

                tp->myAddress.sin_family = AF_INET;
                tp->myAddress.sin_port = htons (UDP_PORT_BASE + nStreams * try + minor);
                tp->myAddress.sin_addr.s_addr = htonl (INADDR_ANY);
                if (bind (tp->socket, (struct sockaddr *)&tp->myAddress, sizeof tp->myAddress) >= 0)
                        break;
                if (++retryCount == 10) {
                        close (tp->socket);
                        releaseStream (minor);
                        return RTEMS_RESOURCE_IN_USE;
                }
        }

        /*
         * Set the UDP destination to the TFTP server
         * port on the remote machine.
         */
        tp->farAddress.sin_family = AF_INET;
        tp->farAddress.sin_addr.s_addr = farAddress;
        tp->farAddress.sin_port = htons (69);

        /*
         * Start the transfer
         */
        tp->firstReply = 1;
        for (;;) {
                /*
                 * Create the request
                 */
                tp->pkbuf.tftpRWRQ.opcode = htons (TFTP_OPCODE_RRQ);
                cp1 = tp->pkbuf.tftpRWRQ.filename_mode;
                cp2 = remoteFilename;
                while ((*cp1++ = *cp2++) != '\0')
                        continue;
                cp2 = "octet";
                while ((*cp1++ = *cp2++) != '\0')
                        continue;
                len = cp1 - (char *)&tp->pkbuf.tftpRWRQ;

                /*
                 * Send the request
                 */
                if (sendto (tp->socket, (char *)&tp->pkbuf, len, 0, 
                                        (struct sockaddr *)&tp->farAddress,
                                        sizeof tp->farAddress) < 0) {
                        close (tp->socket);
                        releaseStream (minor);
                        return RTEMS_UNSATISFIED;
                }

                /*
                 * Get reply
                 */
                len = getPacket (tp);
                if (len >= (int) sizeof tp->pkbuf.tftpACK) {
                        int opcode = ntohs (tp->pkbuf.tftpDATA.opcode);
                        if ((opcode == TFTP_OPCODE_DATA)
                         && (ntohs (tp->pkbuf.tftpDATA.blocknum) == 1)) {
                                tp->nused = 0;
                                tp->blocknum = 1;
                                tp->nleft = len - 2 * sizeof (rtems_unsigned16);
                                tp->eof = (tp->nleft < TFTP_BUFSIZE);
                                if (sendAck (tp) != 0) {
                                        close (tp->socket);
                                        releaseStream (minor);
                                        return RTEMS_UNSATISFIED;
                                }
                                break;
                        }
                        if (opcode == TFTP_OPCODE_ERROR) {
                                tftpSetErrno (tp);
                                close (tp->socket);
                                releaseStream (ap->iop->data0);
                                return RTEMS_INTERNAL_ERROR;
                        }
                }

                /*
                 * Keep trying
                 */
                if (++retryCount >= OPEN_RETRY_LIMIT) {
                        close (tp->socket);
                        releaseStream (minor);
                        return RTEMS_UNSATISFIED;
                }
        }
        return RTEMS_SUCCESSFUL;
}

/*
 * Read from a TFTP stream
 */
rtems_device_driver rtems_tftp_read(
  rtems_device_major_number major,
  rtems_device_minor_number minor,
  void *pargp
)
{
        rtems_libio_rw_args_t *ap = pargp;
        char *bp;
        struct tftpStream *tp;
        int retryCount;
        int nwant;

        tp = ap->iop->data1;

        /*
         * Read till user request is satisfied or EOF is reached
         */
        bp = ap->buffer;
        nwant = ap->count;
        while (nwant) {
                if (tp->nleft) {
                        int count;
                        if (nwant < tp->nleft)
                                count = nwant;
                        else
                                count = tp->nleft;
                        memcpy (bp, &tp->pkbuf.tftpDATA.data[tp->nused], count);
                        tp->nused += count;
                        tp->nleft -= count;
                        bp += count;
                        nwant -= count;
                        if (nwant == 0)
                                break;
                }
                if (tp->eof)
                        break;

                /*
                 * Wait for the next packet
                 */
                retryCount = 0;
                for (;;) {
                        int len = getPacket (tp);
                        if (len >= (int)sizeof tp->pkbuf.tftpACK) {
                                int opcode = ntohs (tp->pkbuf.tftpDATA.opcode);
                                rtems_unsigned16 nextBlock = tp->blocknum + 1;
                                if ((opcode == TFTP_OPCODE_DATA)
                                 && (ntohs (tp->pkbuf.tftpDATA.blocknum) == nextBlock)) {
                                        tp->nused = 0;
                                        tp->nleft = len - 2 * sizeof (rtems_unsigned16);
                                        tp->eof = (tp->nleft < TFTP_BUFSIZE);
                                        tp->blocknum++;
                                        if (sendAck (tp) != 0)
                                                return RTEMS_IO_ERROR;
                                        break;
                                }
                                if (opcode == TFTP_OPCODE_ERROR) {
                                        tftpSetErrno (tp);
                                        return RTEMS_INTERNAL_ERROR;
                                }
                        }

                        /*
                         * Keep trying?
                         */
                        if (++retryCount == IO_RETRY_LIMIT)
                                return RTEMS_IO_ERROR;
                        if (sendAck (tp) != 0)
                                return RTEMS_IO_ERROR;
                }
        }
        ap->bytes_moved = ap->count - nwant;
        return RTEMS_SUCCESSFUL;
}

/*
 * Close a TFTP stream
 */
rtems_device_driver rtems_tftp_close(
  rtems_device_major_number major,
  rtems_device_minor_number minor,
  void *pargp
)
{
        rtems_libio_open_close_args_t *ap = pargp;
        struct tftpStream *tp = ap->iop->data1;;

        if (!tp->eof && !tp->firstReply) {
                /*
                 * Tell the other end to stop
                 */
                rtems_interval ticksPerSecond;
                sendStifle (tp, &tp->farAddress);
                rtems_clock_get (RTEMS_CLOCK_GET_TICKS_PER_SECOND, &ticksPerSecond);
                rtems_task_wake_after (1 + ticksPerSecond / 10);
        }
        close (tp->socket);
        releaseStream (ap->iop->data0);
        return RTEMS_SUCCESSFUL;
}

rtems_device_driver rtems_tftp_write(
  rtems_device_major_number major,
  rtems_device_minor_number minor,
  void *pargp
)
{
        return RTEMS_NOT_CONFIGURED;
}

rtems_device_driver rtems_tftp_control(
  rtems_device_major_number major,
  rtems_device_minor_number minor,
  void *pargp
)
{
        return RTEMS_NOT_CONFIGURED;
}