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hush/networking/tftp.c

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/* ------------------------------------------------------------------------- */
/* tftp.c */
/* */
/* A simple tftp client for busybox. */
/* Tries to follow RFC1350. */
/* Only "octet" mode supported. */
/* Optional blocksize negotiation (RFC2347 + RFC2348) */
/* */
/* Copyright (C) 2001 Magnus Damm <damm@opensource.se> */
/* */
/* Parts of the code based on: */
/* */
/* atftp: Copyright (C) 2000 Jean-Pierre Lefebvre <helix@step.polymtl.ca> */
/* and Remi Lefebvre <remi@debian.org> */
/* */
/* utftp: Copyright (C) 1999 Uwe Ohse <uwe@ohse.de> */
/* */
/* This program 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 of the License, or */
/* (at your option) any later version. */
/* */
/* This program 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 this program; if not, write to the Free Software */
/* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
/* */
/* ------------------------------------------------------------------------- */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <netdb.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <fcntl.h>
#include "busybox.h"
//#define CONFIG_FEATURE_TFTP_DEBUG
#define TFTP_BLOCKSIZE_DEFAULT 512 /* according to RFC 1350, don't change */
#define TFTP_TIMEOUT 5 /* seconds */
/* opcodes we support */
#define TFTP_RRQ 1
#define TFTP_WRQ 2
#define TFTP_DATA 3
#define TFTP_ACK 4
#define TFTP_ERROR 5
#define TFTP_OACK 6
static const char * const tftp_bb_error_msg[] = {
"Undefined error",
"File not found",
"Access violation",
"Disk full or allocation error",
"Illegal TFTP operation",
"Unknown transfer ID",
"File already exists",
"No such user"
};
#ifdef CONFIG_FEATURE_TFTP_GET
# define tftp_cmd_get 1
#else
# define tftp_cmd_get 0
#endif
#ifdef CONFIG_FEATURE_TFTP_PUT
# define tftp_cmd_put (tftp_cmd_get+1)
#else
# define tftp_cmd_put 0
#endif
#ifdef CONFIG_FEATURE_TFTP_BLOCKSIZE
static int tftp_blocksize_check(int blocksize, int bufsize)
{
/* Check if the blocksize is valid:
* RFC2348 says between 8 and 65464,
* but our implementation makes it impossible
* to use blocksizes smaller than 22 octets.
*/
if ((bufsize && (blocksize > bufsize)) ||
(blocksize < 8) || (blocksize > 65464)) {
bb_error_msg("bad blocksize");
return 0;
}
return blocksize;
}
static char *tftp_option_get(char *buf, int len, char *option)
{
int opt_val = 0;
int opt_found = 0;
int k;
while (len > 0) {
/* Make sure the options are terminated correctly */
for (k = 0; k < len; k++) {
if (buf[k] == '\0') {
break;
}
}
if (k >= len) {
break;
}
if (opt_val == 0) {
if (strcasecmp(buf, option) == 0) {
opt_found = 1;
}
}
else {
if (opt_found) {
return buf;
}
}
k++;
buf += k;
len -= k;
opt_val ^= 1;
}
return NULL;
}
#endif
static inline int tftp(const int cmd, const struct hostent *host,
const char *remotefile, int localfd, const unsigned short port, int tftp_bufsize)
{
const int cmd_get = cmd & tftp_cmd_get;
const int cmd_put = cmd & tftp_cmd_put;
const int bb_tftp_num_retries = 5;
struct sockaddr_in sa;
struct sockaddr_in from;
struct timeval tv;
socklen_t fromlen;
fd_set rfds;
char *cp;
unsigned short tmp;
int socketfd;
int len;
int opcode = 0;
int finished = 0;
int timeout = bb_tftp_num_retries;
unsigned short block_nr = 1;
#ifdef CONFIG_FEATURE_TFTP_BLOCKSIZE
int want_option_ack = 0;
#endif
/* Can't use RESERVE_CONFIG_BUFFER here since the allocation
* size varies meaning BUFFERS_GO_ON_STACK would fail */
char *buf=xmalloc(tftp_bufsize + 4);
tftp_bufsize += 4;
if ((socketfd = socket(PF_INET, SOCK_DGRAM, 0)) < 0) {
bb_perror_msg("socket");
return EXIT_FAILURE;
}
len = sizeof(sa);
memset(&sa, 0, len);
bind(socketfd, (struct sockaddr *)&sa, len);
sa.sin_family = host->h_addrtype;
sa.sin_port = port;
memcpy(&sa.sin_addr, (struct in_addr *) host->h_addr,
sizeof(sa.sin_addr));
/* build opcode */
if (cmd_get) {
opcode = TFTP_RRQ;
}
if (cmd_put) {
opcode = TFTP_WRQ;
}
while (1) {
cp = buf;
/* first create the opcode part */
*((unsigned short *) cp) = htons(opcode);
cp += 2;
/* add filename and mode */
if ((cmd_get && (opcode == TFTP_RRQ)) ||
(cmd_put && (opcode == TFTP_WRQ))) {
int too_long = 0;
/* see if the filename fits into buf */
/* and fill in packet */
len = strlen(remotefile) + 1;
if ((cp + len) >= &buf[tftp_bufsize - 1]) {
too_long = 1;
}
else {
safe_strncpy(cp, remotefile, len);
cp += len;
}
if (too_long || ((&buf[tftp_bufsize - 1] - cp) < 6)) {
bb_error_msg("too long remote-filename");
break;
}
/* add "mode" part of the package */
memcpy(cp, "octet", 6);
cp += 6;
#ifdef CONFIG_FEATURE_TFTP_BLOCKSIZE
len = tftp_bufsize - 4; /* data block size */
if (len != TFTP_BLOCKSIZE_DEFAULT) {
if ((&buf[tftp_bufsize - 1] - cp) < 15) {
bb_error_msg("too long remote-filename");
break;
}
/* add "blksize" + number of blocks */
memcpy(cp, "blksize", 8);
cp += 8;
cp += snprintf(cp, 6, "%d", len) + 1;
want_option_ack = 1;
}
#endif
}
/* add ack and data */
if ((cmd_get && (opcode == TFTP_ACK)) ||
(cmd_put && (opcode == TFTP_DATA))) {
*((unsigned short *) cp) = htons(block_nr);
cp += 2;
block_nr++;
if (cmd_put && (opcode == TFTP_DATA)) {
len = bb_full_read(localfd, cp, tftp_bufsize - 4);
if (len < 0) {
bb_perror_msg("read");
break;
}
if (len != (tftp_bufsize - 4)) {
finished++;
}
cp += len;
}
}
/* send packet */
timeout = bb_tftp_num_retries; /* re-initialize */
do {
len = cp - buf;
#ifdef CONFIG_FEATURE_TFTP_DEBUG
fprintf(stderr, "sending %u bytes\n", len);
for (cp = buf; cp < &buf[len]; cp++)
fprintf(stderr, "%02x ", (unsigned char)*cp);
fprintf(stderr, "\n");
#endif
if (sendto(socketfd, buf, len, 0,
(struct sockaddr *) &sa, sizeof(sa)) < 0) {
bb_perror_msg("send");
len = -1;
break;
}
if (finished && (opcode == TFTP_ACK)) {
break;
}
/* receive packet */
memset(&from, 0, sizeof(from));
fromlen = sizeof(from);
tv.tv_sec = TFTP_TIMEOUT;
tv.tv_usec = 0;
FD_ZERO(&rfds);
FD_SET(socketfd, &rfds);
switch (select(socketfd + 1, &rfds, NULL, NULL, &tv)) {
case 1:
len = recvfrom(socketfd, buf, tftp_bufsize, 0,
(struct sockaddr *) &from, &fromlen);
if (len < 0) {
bb_perror_msg("recvfrom");
break;
}
timeout = 0;
if (sa.sin_port == port) {
sa.sin_port = from.sin_port;
}
if (sa.sin_port == from.sin_port) {
break;
}
/* fall-through for bad packets! */
/* discard the packet - treat as timeout */
timeout = bb_tftp_num_retries;
case 0:
bb_error_msg("timeout");
timeout--;
if (timeout == 0) {
len = -1;
bb_error_msg("last timeout");
}
break;
default:
bb_perror_msg("select");
len = -1;
}
} while (timeout && (len >= 0));
if ((finished) || (len < 0)) {
break;
}
/* process received packet */
opcode = ntohs(*((unsigned short *) buf));
tmp = ntohs(*((unsigned short *) &buf[2]));
#ifdef CONFIG_FEATURE_TFTP_DEBUG
fprintf(stderr, "received %d bytes: %04x %04x\n", len, opcode, tmp);
#endif
if (opcode == TFTP_ERROR) {
const char *msg = NULL;
if (buf[4] != '\0') {
msg = &buf[4];
buf[tftp_bufsize - 1] = '\0';
} else if (tmp < (sizeof(tftp_bb_error_msg)
/ sizeof(char *))) {
msg = tftp_bb_error_msg[tmp];
}
if (msg) {
bb_error_msg("server says: %s", msg);
}
break;
}
#ifdef CONFIG_FEATURE_TFTP_BLOCKSIZE
if (want_option_ack) {
want_option_ack = 0;
if (opcode == TFTP_OACK) {
/* server seems to support options */
char *res;
res = tftp_option_get(&buf[2], len-2,
"blksize");
if (res) {
int blksize = atoi(res);
if (tftp_blocksize_check(blksize,
tftp_bufsize - 4)) {
if (cmd_put) {
opcode = TFTP_DATA;
}
else {
opcode = TFTP_ACK;
}
#ifdef CONFIG_FEATURE_TFTP_DEBUG
fprintf(stderr, "using blksize %u\n", blksize);
#endif
tftp_bufsize = blksize + 4;
block_nr = 0;
continue;
}
}
/* FIXME:
* we should send ERROR 8 */
bb_error_msg("bad server option");
break;
}
bb_error_msg("warning: blksize not supported by server"
" - reverting to 512");
tftp_bufsize = TFTP_BLOCKSIZE_DEFAULT + 4;
}
#endif
if (cmd_get && (opcode == TFTP_DATA)) {
if (tmp == block_nr) {
len = bb_full_write(localfd, &buf[4], len - 4);
if (len < 0) {
bb_perror_msg("write");
break;
}
if (len != (tftp_bufsize - 4)) {
finished++;
}
opcode = TFTP_ACK;
continue;
}
/* in case the last ack disappeared into the ether */
if ( tmp == (block_nr - 1) ) {
--block_nr;
opcode = TFTP_ACK;
continue;
} else if (tmp + 1 == block_nr) {
/* Server lost our TFTP_ACK. Resend it */
block_nr = tmp;
opcode = TFTP_ACK;
continue;
}
}
if (cmd_put && (opcode == TFTP_ACK)) {
if (tmp == (unsigned short)(block_nr - 1)) {
if (finished) {
break;
}
opcode = TFTP_DATA;
continue;
}
}
}
#ifdef CONFIG_FEATURE_CLEAN_UP
close(socketfd);
free(buf);
#endif
return finished ? EXIT_SUCCESS : EXIT_FAILURE;
}
int tftp_main(int argc, char **argv)
{
struct hostent *host = NULL;
const char *localfile = NULL;
const char *remotefile = NULL;
int port;
int cmd = 0;
int fd = -1;
int flags = 0;
int opt;
int result;
int blocksize = TFTP_BLOCKSIZE_DEFAULT;
/* figure out what to pass to getopt */
#ifdef CONFIG_FEATURE_TFTP_BLOCKSIZE
char *sblocksize = NULL;
#define BS "b:"
#define BS_ARG , &sblocksize
#else
#define BS
#define BS_ARG
#endif
#ifdef CONFIG_FEATURE_TFTP_GET
#define GET "g"
#define GET_COMPL ":g"
#else
#define GET
#define GET_COMP
#endif
#ifdef CONFIG_FEATURE_TFTP_PUT
#define PUT "p"
#define PUT_COMPL ":p"
#else
#define PUT
#define PUT_COMPL
#endif
#if defined(CONFIG_FEATURE_TFTP_GET) && defined(CONFIG_FEATURE_TFTP_PUT)
bb_opt_complementally = GET_COMPL PUT_COMPL ":?g--p:p--g";
#elif defined(CONFIG_FEATURE_TFTP_GET) || defined(CONFIG_FEATURE_TFTP_PUT)
bb_opt_complementally = GET_COMPL PUT_COMPL;
#else
/* XXX: may be should #error ? */
#endif
opt = bb_getopt_ulflags(argc, argv, GET PUT "l:r:" BS,
&localfile, &remotefile BS_ARG);
#ifdef CONFIG_FEATURE_TFTP_BLOCKSIZE
if(sblocksize) {
blocksize = atoi(sblocksize);
if (!tftp_blocksize_check(blocksize, 0)) {
return EXIT_FAILURE;
}
}
#endif
cmd &= (tftp_cmd_get & tftp_cmd_put);
#ifdef CONFIG_FEATURE_TFTP_GET
if(cmd == tftp_cmd_get)
flags = O_WRONLY | O_CREAT | O_TRUNC;
#endif
#ifdef CONFIG_FEATURE_TFTP_PUT
if(cmd == tftp_cmd_put)
flags = O_RDONLY;
#endif
if(localfile == NULL)
localfile = remotefile;
if(remotefile == NULL)
remotefile = localfile;
/* XXX: I corrected this, but may be wrong too. vodz */
if(localfile==NULL || strcmp(localfile, "-") == 0) {
fd = fileno((cmd==tftp_cmd_get)? stdout : stdin);
} else if (fd==-1) {
fd = open(localfile, flags, 0644);
}
if (fd < 0) {
bb_perror_msg_and_die("local file");
}
/* XXX: argv[optind] and/or argv[optind + 1] may be NULL! */
host = xgethostbyname(argv[optind]);
port = bb_lookup_port(argv[optind + 1], "udp", 69);
#ifdef CONFIG_FEATURE_TFTP_DEBUG
fprintf(stderr, "using server \"%s\", remotefile \"%s\", "
"localfile \"%s\".\n",
inet_ntoa(*((struct in_addr *) host->h_addr)),
remotefile, localfile);
#endif
result = tftp(cmd, host, remotefile, fd, port, blocksize);
#ifdef CONFIG_FEATURE_CLEAN_UP
if (!(fd == STDOUT_FILENO || fd == STDIN_FILENO)) {
close(fd);
}
#endif
return(result);
}
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