tftp_client.c

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//==========================================================================
//
//      lib/tftp_client.c
//
//      TFTP client support
//
//==========================================================================
//####ECOSGPLCOPYRIGHTBEGIN####
// -------------------------------------------
// This file is part of eCos, the Embedded Configurable Operating System.
// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
// Copyright (C) 2003 [e-mail]
//
// eCos is free software; you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 2 or (at your option) any later version.
//
// eCos is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
// for more details.
//
// You should have received a copy of the GNU General Public License along
// with eCos; if not, write to the Free Software Foundation, Inc.,
// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
//
// As a special exception, if other files instantiate templates or use macros
// or inline functions from this file, or you compile this file and link it
// with other works to produce a work based on this file, this file does not
// by itself cause the resulting work to be covered by the GNU General Public
// License. However the source code for this file must still be made available
// in accordance with section (3) of the GNU General Public License.
//
// This exception does not invalidate any other reasons why a work based on
// this file might be covered by the GNU General Public License.
//
// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.
// at http://sources.redhat.com/ecos/ecos-license/
// -------------------------------------------
//####ECOSGPLCOPYRIGHTEND####
//==========================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s):    gthomas
// Contributors: gthomas, [e-mail]
// Date:         2000-04-06
// Purpose:      
// Description:  
//              
//
//####DESCRIPTIONEND####
//
//==========================================================================

// TFTP client support

#include <network.h>
#include <arpa/tftp.h>
#include <tftp_support.h>
#include <stdlib.h>
#include <stdio.h>

#define min(x,y) (x<y ? x : y)

//
// Read a file from a host into a local buffer.  Returns the
// number of bytes actually read, or (-1) if an error occurs.
// On error, *err will hold the reason.
// This version uses the server name. This can be a name for DNS lookup
// or a dotty or colony number format for IPv4 or IPv6.
static int tftp_client_get_inner(char *data,
                    const char * const filename,
                    const char * const server,
                    const int port,
                    char *buf,
                    int len,
                    const int mode,
                    int * const err
#ifdef CYGPKG_NET_TFTPD_CLIENT_BIG_PACKET
                    ,int negotiate
#endif
                    ) {
        
        int blksize=SEGSIZE;
    int result = 0;
    int s=-1;
    int actual_len, data_len;
    socklen_t from_len, recv_len;
    static int get_port = 7700;
    struct addrinfo * addrinfo;
    struct addrinfo * res;
    struct addrinfo hints;
    int error;

    struct sockaddr local_addr, from_addr;
    struct tftphdr *hdr = (struct tftphdr *)data;
    const char *fp;
    char *cp, *bp;
    struct timeval timeout;
    unsigned short last_good_block = 0;
    fd_set fds;
    int total_timeouts = 0;

    *err = 0;  // Just in case

    // Create initial request
    hdr->th_opcode = htons(RRQ);  // Read file
    cp = (char *)&hdr->th_stuff;
    fp = filename;
    while (*fp) *cp++ = *fp++;
    *cp++ = '\0';
    if (mode == TFTP_NETASCII) {
        fp = "NETASCII";
    } else if (mode == TFTP_OCTET) {
        fp = "OCTET";
    } else {
        *err = TFTP_INVALID;
        return -1;
    }
    while (*fp) *cp++ = *fp++;
    *cp++ = '\0';
#ifdef CYGPKG_NET_TFTPD_CLIENT_BIG_PACKET
    if (negotiate) {
        fp="blksize";
        while (*fp) 
          *cp++ = *fp++;
        *cp++ = '\0';
        cp+=sprintf(cp, "%d", CYGPKG_NET_TFTPD_CLIENT_BIG_PACKET_SIZE);
        *cp++ = '\0';
    }
#endif

    memset(&hints,0,sizeof(hints));
    hints.ai_family = PF_UNSPEC;
    error = getaddrinfo(server, "tftp", &hints, &res);
    if (error) {
      *err = TFTP_NETERR;
      return -1;
    }
    
    addrinfo = res;
    while (addrinfo) {
      s = socket(addrinfo->ai_family, addrinfo->ai_socktype, 
                 addrinfo->ai_protocol);
      if (s >= 0) {
        memcpy(&local_addr,addrinfo->ai_addr,addrinfo->ai_addrlen);
        switch(addrinfo->ai_addr->sa_family) {
        case AF_INET: {
          struct sockaddr_in * saddr = 
            (struct sockaddr_in *) addrinfo->ai_addr;
          struct sockaddr_in * laddr = 
            (struct sockaddr_in *) &local_addr;
          if (port) {
            saddr->sin_port = htons(port);
          }
          laddr->sin_port = htons(get_port++);
          laddr->sin_addr.s_addr = INADDR_ANY;
          break;
        }
#ifdef CYGPKG_NET_INET6
        case AF_INET6: {
          struct sockaddr_in6 * saddr = 
            (struct sockaddr_in6 *) addrinfo->ai_addr;
          struct sockaddr_in6 * laddr = 
            (struct sockaddr_in6 *) &local_addr;
          if (port) {
            saddr->sin6_port = htons(port);
          }
          laddr->sin6_port = htons(get_port++);
          laddr->sin6_addr = in6addr_any;
          break;
        }
#endif
        default:
          *err = TFTP_NETERR;
          goto out;
        }

        if (bind(s,&local_addr,addrinfo->ai_addrlen) < 0) {
          *err = TFTP_NETERR;
          goto out;
        }
        
        // Send request
        if (sendto(s, data, (int)(cp-data), 0, 
                   addrinfo->ai_addr, 
                   addrinfo->ai_addrlen) < 0) {
          // Problem sending request
          *err = TFTP_NETERR;
          goto nextaddr;
        }

        // Read data
        bp = buf;
        while (true) {
          timeout.tv_sec = TFTP_TIMEOUT_PERIOD;
          timeout.tv_usec = 0;
          FD_ZERO(&fds);
          FD_SET(s, &fds);
          if (select(s+1, &fds, 0, 0, &timeout) <= 0) {
            total_timeouts++;
            if ((last_good_block == 0) && (total_timeouts > TFTP_RETRIES_MAX)) {
              // Timeout - no data received. Probably no server.
              *err = TFTP_TIMEOUT;
              goto nextaddr;
            }
            if (total_timeouts > TFTP_TIMEOUT_MAX) {
              // Timeout - have received data. Network problem?
              *err = TFTP_TIMEOUT;
              goto out;
            }
            
            if (last_good_block == 0 ) {
              // Send request
              if (sendto(s, data, (int)(cp-data), 0, 
                         addrinfo->ai_addr, 
                         addrinfo->ai_addrlen) < 0) {
                // Problem sending request
                *err = TFTP_NETERR;
                goto nextaddr;
              }
            } else {
              // Try resending last ACK
              hdr->th_opcode = htons(ACK);
              hdr->th_block = htons(last_good_block);
              if (sendto(s, data, 4 /* FIXME */, 0, 
                         &from_addr, from_len) < 0) {
                // Problem sending request
                *err = TFTP_NETERR;
                goto out;
              }
            }
          } else {
            recv_len = blksize+sizeof(struct tftphdr);
            from_len = sizeof(from_addr);
            if ((data_len = recvfrom(s, data, recv_len, 0, 
                                     &from_addr, &from_len)) < 0) {
              // What happened?
              *err = TFTP_NETERR;
              goto out;
            }
#ifdef CYGPKG_NET_TFTPD_CLIENT_BIG_PACKET
            if (ntohs(hdr->th_opcode) == OACK) {
              // We can have only *one* option, the one we sent..
              if (strncmp(data+2, "blksize", data_len)==0) {
                blksize=atol(data+2+strlen("blksize")+1);
              } else {
                // option ignored, use default.
              }
              // Send out the ACK
              hdr->th_opcode = htons(ACK);
              hdr->th_block = htons(last_good_block);
              if (sendto(s, data, 4 /* FIXME */, 0, 
                         &from_addr, from_len) < 0) {
                // Problem sending request
                *err = TFTP_NETERR;
                goto out;
              }
            } else
#endif
              if (ntohs(hdr->th_opcode) == DATA) {
                actual_len = 0;
                if (ntohs(hdr->th_block) == (last_good_block+1)) {
                  // Consume this data
                  cp = hdr->th_data;
                  data_len -= 4;  /* Sizeof TFTP header */
                  actual_len = data_len;
                  result += actual_len;
                  if (len<data_len)
                    {
                      // Buffer overflow
                      *err = TFTP_TOOLARGE;
                      goto out;
                    }
                  memcpy(bp, cp, data_len);
                  bp+=data_len;
                  len-=data_len;
                  last_good_block++;
                } else {
                  // To prevent an out-of-sequence packet from
                  // terminating transmission prematurely, set
                  // actual_len to a full size packet.
                  actual_len = blksize;
                }
                // Send out the ACK
                hdr->th_opcode = htons(ACK);
                hdr->th_block = htons(last_good_block);
                if (sendto(s, data, 4 /* FIXME */, 0, 
                           &from_addr, from_len) < 0) {
                  // Problem sending request
                  *err = TFTP_NETERR;
                  goto out;
                }
                // A short packet marks the end of the file.
                /* 4 = Sizeof TFTP header */
                if ((actual_len >= 0) && (actual_len < blksize)) {
                  // End of data
                  close(s);
                  freeaddrinfo(res);
                  return result;
                }
              } else 
                if (ntohs(hdr->th_opcode) == ERROR) {
                  *err = ntohs(hdr->th_code);
                  goto out;
                } else {
                  // What kind of packet is this?
                  *err = TFTP_PROTOCOL;
                  goto out;
                }
          }
        }
      }
      // If we got here, it means there was a problem connecting to the 
      // server. Try the next address returned by getaddrinfo
    nextaddr:
      if (-1 != s) {
        close(s);
      }
      addrinfo=addrinfo->ai_next;
    }
    // We ran into problems. Cleanup
 out:
    if (-1 != s) {
      close (s);
    }
    freeaddrinfo(res);
    return -1;
}