mirror of
https://github.com/sheumann/hush.git
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523 lines
11 KiB
C
523 lines
11 KiB
C
/* vi: set sw=4 ts=4: */
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/* -------------------------------------------------------------------------
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* tftp.c
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*
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* A simple tftp client for busybox.
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* Tries to follow RFC1350.
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* Only "octet" mode supported.
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* Optional blocksize negotiation (RFC2347 + RFC2348)
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*
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* Copyright (C) 2001 Magnus Damm <damm@opensource.se>
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*
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* Parts of the code based on:
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*
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* atftp: Copyright (C) 2000 Jean-Pierre Lefebvre <helix@step.polymtl.ca>
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* and Remi Lefebvre <remi@debian.org>
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*
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* utftp: Copyright (C) 1999 Uwe Ohse <uwe@ohse.de>
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*
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* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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* ------------------------------------------------------------------------- */
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#include "busybox.h"
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#define TFTP_BLOCKSIZE_DEFAULT 512 /* according to RFC 1350, don't change */
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#define TFTP_TIMEOUT 5 /* seconds */
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#define TFTP_NUM_RETRIES 5 /* number of retries */
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/* opcodes we support */
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#define TFTP_RRQ 1
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#define TFTP_WRQ 2
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#define TFTP_DATA 3
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#define TFTP_ACK 4
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#define TFTP_ERROR 5
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#define TFTP_OACK 6
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static const char *const tftp_bb_error_msg[] = {
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"Undefined error",
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"File not found",
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"Access violation",
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"Disk full or allocation error",
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"Illegal TFTP operation",
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"Unknown transfer ID",
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"File already exists",
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"No such user"
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};
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#if ENABLE_FEATURE_TFTP_GET && !ENABLE_FEATURE_TFTP_PUT
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#define USE_GETPUT(a)
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#define CMD_GET(cmd) 1
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#define CMD_PUT(cmd) 0
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#elif !ENABLE_FEATURE_TFTP_GET && ENABLE_FEATURE_TFTP_PUT
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#define USE_GETPUT(a)
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#define CMD_GET(cmd) 0
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#define CMD_PUT(cmd) 1
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#else
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#define USE_GETPUT(a) a
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/* masks coming from getpot32 */
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#define CMD_GET(cmd) (cmd & 1)
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#define CMD_PUT(cmd) (cmd & 2)
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#endif
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/* NB: in the code below
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* CMD_GET(cmd) and CMD_GET(cmd) are mutually exclusive
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*/
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#if ENABLE_FEATURE_TFTP_BLOCKSIZE
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static int tftp_blocksize_check(int blocksize, int bufsize)
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{
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/* Check if the blocksize is valid:
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* RFC2348 says between 8 and 65464,
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* but our implementation makes it impossible
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* to use blocksizes smaller than 22 octets.
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*/
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if ((bufsize && (blocksize > bufsize))
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|| (blocksize < 8) || (blocksize > 65564)
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) {
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bb_error_msg("bad blocksize");
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return 0;
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}
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return blocksize;
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}
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static char *tftp_option_get(char *buf, int len, const char * const option)
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{
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int opt_val = 0;
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int opt_found = 0;
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int k;
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while (len > 0) {
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/* Make sure the options are terminated correctly */
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for (k = 0; k < len; k++) {
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if (buf[k] == '\0') {
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break;
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}
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}
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if (k >= len) {
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break;
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}
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if (opt_val == 0) {
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if (strcasecmp(buf, option) == 0) {
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opt_found = 1;
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}
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} else {
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if (opt_found) {
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return buf;
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}
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}
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k++;
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buf += k;
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len -= k;
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opt_val ^= 1;
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}
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return NULL;
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}
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#endif
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static int tftp(
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#if ENABLE_FEATURE_TFTP_GET && ENABLE_FEATURE_TFTP_PUT
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const int cmd,
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#endif
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const len_and_sockaddr *peer_lsa,
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const char *remotefile, const int localfd,
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unsigned port, int tftp_bufsize)
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{
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struct timeval tv;
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fd_set rfds;
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int socketfd;
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int len;
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int opcode = 0;
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int finished = 0;
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int timeout = TFTP_NUM_RETRIES;
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uint16_t block_nr = 1;
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uint16_t tmp;
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char *cp;
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USE_FEATURE_TFTP_BLOCKSIZE(int want_option_ack = 0;)
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/* Can't use RESERVE_CONFIG_BUFFER here since the allocation
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* size varies meaning BUFFERS_GO_ON_STACK would fail */
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/* We must keep the transmit and receive buffers seperate */
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/* In case we rcv a garbage pkt and we need to rexmit the last pkt */
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char *xbuf = xmalloc(tftp_bufsize += 4);
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char *rbuf = xmalloc(tftp_bufsize);
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port = htons(port);
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socketfd = xsocket(peer_lsa->sa.sa_family, SOCK_DGRAM, 0);
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/* build opcode */
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opcode = TFTP_WRQ;
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if (CMD_GET(cmd)) {
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opcode = TFTP_RRQ;
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}
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while (1) {
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cp = xbuf;
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/* first create the opcode part */
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*((uint16_t*)cp) = htons(opcode);
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cp += 2;
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/* add filename and mode */
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if (CMD_GET(cmd) ? (opcode == TFTP_RRQ) : (opcode == TFTP_WRQ)) {
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int too_long = 0;
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/* see if the filename fits into xbuf
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* and fill in packet. */
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len = strlen(remotefile) + 1;
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if ((cp + len) >= &xbuf[tftp_bufsize - 1]) {
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too_long = 1;
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} else {
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safe_strncpy(cp, remotefile, len);
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cp += len;
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}
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if (too_long || (&xbuf[tftp_bufsize - 1] - cp) < sizeof("octet")) {
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bb_error_msg("remote filename too long");
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break;
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}
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/* add "mode" part of the package */
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memcpy(cp, "octet", sizeof("octet"));
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cp += sizeof("octet");
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#if ENABLE_FEATURE_TFTP_BLOCKSIZE
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len = tftp_bufsize - 4; /* data block size */
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if (len != TFTP_BLOCKSIZE_DEFAULT) {
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if ((&xbuf[tftp_bufsize - 1] - cp) < 15) {
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bb_error_msg("remote filename too long");
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break;
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}
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/* add "blksize" + number of blocks */
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memcpy(cp, "blksize", sizeof("blksize"));
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cp += sizeof("blksize");
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cp += snprintf(cp, 6, "%d", len) + 1;
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want_option_ack = 1;
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}
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#endif
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}
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/* add ack and data */
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if (CMD_GET(cmd) ? (opcode == TFTP_ACK) : (opcode == TFTP_DATA)) {
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*((uint16_t*)cp) = htons(block_nr);
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cp += 2;
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block_nr++;
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if (CMD_PUT(cmd) && (opcode == TFTP_DATA)) {
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len = full_read(localfd, cp, tftp_bufsize - 4);
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if (len < 0) {
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bb_perror_msg(bb_msg_read_error);
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break;
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}
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if (len != (tftp_bufsize - 4)) {
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finished++;
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}
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cp += len;
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}
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}
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/* send packet */
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timeout = TFTP_NUM_RETRIES; /* re-initialize */
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do {
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len = cp - xbuf;
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#if ENABLE_DEBUG_TFTP
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fprintf(stderr, "sending %u bytes\n", len);
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for (cp = xbuf; cp < &xbuf[len]; cp++)
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fprintf(stderr, "%02x ", (unsigned char) *cp);
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fprintf(stderr, "\n");
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#endif
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if (sendto(socketfd, xbuf, len, 0,
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&peer_lsa->sa, peer_lsa->len) < 0) {
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bb_perror_msg("send");
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len = -1;
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break;
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}
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if (finished && (opcode == TFTP_ACK)) {
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break;
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}
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/* receive packet */
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tv.tv_sec = TFTP_TIMEOUT;
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tv.tv_usec = 0;
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FD_ZERO(&rfds);
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FD_SET(socketfd, &rfds);
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switch (select(socketfd + 1, &rfds, NULL, NULL, &tv)) {
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struct sockaddr *from;
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socklen_t fromlen;
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case 1:
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fromlen = peer_lsa->len;
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from = alloca(fromlen);
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memset(from, 0, fromlen);
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len = recvfrom(socketfd, rbuf, tftp_bufsize, 0,
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from, &fromlen);
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if (len < 0) {
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bb_perror_msg("recvfrom");
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break;
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}
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timeout = 0;
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if (from->sa_family == peer_lsa->sa.sa_family) {
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#if ENABLE_FEATURE_IPV6
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if (from->sa_family == AF_INET6
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&& ((struct sockaddr_in6*)from)->sin6_port == port
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)
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break;
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#endif
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/* Non-internet sockets are ok */
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if (from->sa_family != AF_INET)
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break;
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if (((struct sockaddr_in*)from)->sin_port == port)
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break;
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}
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/* family doesn't match, or
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* it is INET[v6] and port doesn't match -
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* fall-through for bad packets!
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* (discard the packet - treat as timeout) */
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timeout = TFTP_NUM_RETRIES;
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case 0:
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bb_error_msg("timeout");
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timeout--;
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if (timeout == 0) {
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len = -1;
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bb_error_msg("last timeout");
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}
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break;
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default:
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bb_perror_msg("select");
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len = -1;
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}
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} while (timeout && (len >= 0));
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if (finished || (len < 0)) {
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break;
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}
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/* process received packet */
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opcode = ntohs( ((uint16_t*)rbuf)[0] );
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tmp = ntohs( ((uint16_t*)rbuf)[1] );
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#if ENABLE_DEBUG_TFTP
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fprintf(stderr, "received %d bytes: %04x %04x\n", len, opcode, tmp);
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#endif
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if (opcode == TFTP_ERROR) {
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const char *msg = NULL;
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if (rbuf[4] != '\0') {
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msg = &rbuf[4];
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rbuf[tftp_bufsize - 1] = '\0';
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} else if (tmp < (sizeof(tftp_bb_error_msg)
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/ sizeof(char *))) {
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msg = tftp_bb_error_msg[tmp];
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}
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if (msg) {
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bb_error_msg("server says: %s", msg);
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}
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break;
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}
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#if ENABLE_FEATURE_TFTP_BLOCKSIZE
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if (want_option_ack) {
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want_option_ack = 0;
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if (opcode == TFTP_OACK) {
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/* server seems to support options */
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char *res;
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res = tftp_option_get(&rbuf[2], len - 2, "blksize");
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if (res) {
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int blksize = xatoi_u(res);
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if (tftp_blocksize_check(blksize, tftp_bufsize - 4)) {
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if (CMD_PUT(cmd)) {
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opcode = TFTP_DATA;
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} else {
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opcode = TFTP_ACK;
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}
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#if ENABLE_DEBUG_TFTP
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fprintf(stderr, "using blksize %u\n",
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blksize);
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#endif
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tftp_bufsize = blksize + 4;
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block_nr = 0;
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continue;
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}
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}
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/* FIXME:
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* we should send ERROR 8 */
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bb_error_msg("bad server option");
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break;
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}
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bb_error_msg("warning: blksize not supported by server"
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" - reverting to 512");
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tftp_bufsize = TFTP_BLOCKSIZE_DEFAULT + 4;
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}
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#endif
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if (CMD_GET(cmd) && (opcode == TFTP_DATA)) {
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if (tmp == block_nr) {
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len = full_write(localfd, &rbuf[4], len - 4);
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if (len < 0) {
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bb_perror_msg(bb_msg_write_error);
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break;
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}
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if (len != (tftp_bufsize - 4)) {
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finished++;
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}
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opcode = TFTP_ACK;
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continue;
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}
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/* in case the last ack disappeared into the ether */
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if (tmp == (block_nr - 1)) {
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--block_nr;
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opcode = TFTP_ACK;
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continue;
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// tmp==(block_nr-1) and (tmp+1)==block_nr is always same, I think. wtf?
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} else if (tmp + 1 == block_nr) {
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/* Server lost our TFTP_ACK. Resend it */
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block_nr = tmp;
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opcode = TFTP_ACK;
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continue;
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}
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}
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if (CMD_PUT(cmd) && (opcode == TFTP_ACK)) {
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if (tmp == (uint16_t) (block_nr - 1)) {
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if (finished) {
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break;
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}
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opcode = TFTP_DATA;
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continue;
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}
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}
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}
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#if ENABLE_FEATURE_CLEAN_UP
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close(socketfd);
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free(xbuf);
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free(rbuf);
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#endif
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return finished ? EXIT_SUCCESS : EXIT_FAILURE;
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}
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int tftp_main(int argc, char **argv)
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{
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len_and_sockaddr *peer_lsa;
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const char *localfile = NULL;
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const char *remotefile = NULL;
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#if ENABLE_FEATURE_TFTP_BLOCKSIZE
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const char *sblocksize = NULL;
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#endif
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int port;
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USE_GETPUT(int cmd;)
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int fd = -1;
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int flags = 0;
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int result;
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int blocksize = TFTP_BLOCKSIZE_DEFAULT;
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/* -p or -g is mandatory, and they are mutually exclusive */
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opt_complementary = "" USE_FEATURE_TFTP_GET("g:") USE_FEATURE_TFTP_PUT("p:")
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USE_GETPUT("?g--p:p--g");
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USE_GETPUT(cmd =) getopt32(argc, argv,
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USE_FEATURE_TFTP_GET("g") USE_FEATURE_TFTP_PUT("p")
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"l:r:" USE_FEATURE_TFTP_BLOCKSIZE("b:"),
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&localfile, &remotefile
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USE_FEATURE_TFTP_BLOCKSIZE(, &sblocksize));
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flags = O_RDONLY;
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if (CMD_GET(cmd))
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flags = O_WRONLY | O_CREAT | O_TRUNC;
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#if ENABLE_FEATURE_TFTP_BLOCKSIZE
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if (sblocksize) {
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blocksize = xatoi_u(sblocksize);
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if (!tftp_blocksize_check(blocksize, 0)) {
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return EXIT_FAILURE;
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}
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}
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#endif
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if (localfile == NULL)
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localfile = remotefile;
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if (remotefile == NULL)
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remotefile = localfile;
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if ((localfile == NULL && remotefile == NULL) || (argv[optind] == NULL))
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bb_show_usage();
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if (localfile == NULL || LONE_DASH(localfile)) {
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fd = CMD_GET(cmd) ? STDOUT_FILENO : STDIN_FILENO;
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} else {
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fd = xopen3(localfile, flags, 0644);
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}
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port = bb_lookup_port(argv[optind + 1], "udp", 69);
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peer_lsa = host2sockaddr(argv[optind], port);
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#if ENABLE_DEBUG_TFTP
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fprintf(stderr, "using server \"%s\", "
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"remotefile \"%s\", localfile \"%s\".\n",
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xmalloc_sockaddr2dotted(&peer_lsa->sa, peer_lsa->len),
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remotefile, localfile);
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#endif
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result = tftp(
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#if ENABLE_FEATURE_TFTP_GET && ENABLE_FEATURE_TFTP_PUT
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cmd,
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#endif
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peer_lsa, remotefile, fd, port, blocksize);
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if (fd > 1) {
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if (ENABLE_FEATURE_CLEAN_UP)
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close(fd);
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if (CMD_GET(cmd) && result != EXIT_SUCCESS)
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unlink(localfile);
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}
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return result;
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}
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