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hush/networking/tftp.c
Eric Andersen 76fa8ea790 Apply Glenn's tftp rewrite
2001-08-20 17:47:49 +00:00

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/* ------------------------------------------------------------------------- */
/* tftp.c */
/* */
/* A simple tftp client for busybox. */
/* Tries to follow RFC1350. */
/* Only "octet" mode and 512-byte data blocks are supported. */
/* */
/* 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 BB_FEATURE_TFTP_DEBUG
static const char *tftp_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"
};
const int tftp_cmd_get = 1;
const int tftp_cmd_put = 2;
static inline int tftp(const int cmd, const struct hostent *host,
const char *serverfile, int localfd, const int 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;
int block_nr = 1;
RESERVE_BB_BUFFER(buf, tftp_bufsize + 4); // Why 4 ?
tftp_bufsize += 4;
if ((socketfd = socket(PF_INET, SOCK_DGRAM, 0)) < 0) {
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 = htons(port);
memcpy(&sa.sin_addr, (struct in_addr *) host->h_addr,
sizeof(sa.sin_addr));
/* build opcode */
if (cmd_get) {
opcode = 1; // read request = 1
}
if (cmd_put) {
opcode = 2; // write request = 2
}
while (1) {
/* build packet of type "opcode" */
cp = buf;
*((unsigned short *) cp) = htons(opcode);
cp += 2;
/* add filename and mode */
if ((cmd_get && (opcode == 1)) || // read request = 1
(cmd_put && (opcode == 2))) { // write request = 2
/* what is this trying to do ? */
while (cp != &buf[tftp_bufsize - 1]) {
if ((*cp = *serverfile++) == '\0')
break;
cp++;
}
/* and this ? */
if ((*cp != '\0') || (&buf[tftp_bufsize - 1] - cp) < 7) {
error_msg("too long server-filename");
break;
}
memcpy(cp + 1, "octet", 6);
cp += 7;
}
/* add ack and data */
if ((cmd_get && (opcode == 4)) || // acknowledgement = 4
(cmd_put && (opcode == 3))) { // data packet == 3
*((unsigned short *) cp) = htons(block_nr);
cp += 2;
block_nr++;
if (cmd_put && (opcode == 3)) { // data packet == 3
len = read(localfd, cp, tftp_bufsize - 4);
if (len < 0) {
perror_msg("read");
break;
}
if (len != (tftp_bufsize - 4)) {
finished++;
}
cp += len;
} else if (finished) {
break;
}
}
/* send packet */
do {
len = cp - buf;
#ifdef BB_FEATURE_TFTP_DEBUG
printf("sending %u bytes\n", len);
for (cp = buf; cp < &buf[len]; cp++)
printf("%02x ", *cp);
printf("\n");
#endif
if (sendto(socketfd, buf, len, 0,
(struct sockaddr *) &sa, sizeof(sa)) < 0) {
perror_msg("send");
len = -1;
break;
}
/* receive packet */
memset(&from, 0, sizeof(from));
fromlen = sizeof(from);
tv.tv_sec = 5; // BB_TFPT_TIMEOUT = 5
tv.tv_usec = 0;
FD_ZERO(&rfds);
FD_SET(socketfd, &rfds);
switch (select(FD_SETSIZE, &rfds, NULL, NULL, &tv)) {
case 1:
len = recvfrom(socketfd, buf, tftp_bufsize, 0,
(struct sockaddr *) &from, &fromlen);
if (len < 0) {
perror_msg("recvfrom");
break;
}
timeout = 0;
if (sa.sin_port == htons(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:
error_msg("timeout");
if (timeout == 0) {
len = -1;
error_msg("last timeout");
} else {
timeout--;
}
break;
default:
perror_msg("select");
len = -1;
}
} while (timeout && (len >= 0));
if (len < 0) {
break;
}
/* process received packet */
opcode = ntohs(*((unsigned short *) buf));
tmp = ntohs(*((unsigned short *) &buf[2]));
#ifdef BB_FEATURE_TFTP_DEBUG
printf("received %d bytes: %04x %04x\n", len, opcode, tmp);
#endif
if (cmd_get && (opcode == 3)) { // data packet == 3
if (tmp == block_nr) {
len = write(localfd, &buf[4], len - 4);
if (len < 0) {
perror_msg("write");
break;
}
if (len != (tftp_bufsize - 4)) {
finished++;
}
opcode = 4; // acknowledgement = 4
continue;
}
}
if (cmd_put && (opcode == 4)) { // acknowledgement = 4
if (tmp == (block_nr - 1)) {
if (finished) {
break;
}
opcode = 3; // data packet == 3
continue;
}
}
if (opcode == 5) { // error code == 5
char *msg = NULL;
if (buf[4] != '\0') {
msg = &buf[4];
buf[tftp_bufsize - 1] = '\0';
} else if (tmp < (sizeof(tftp_error_msg) / sizeof(char *))) {
msg = (char *) tftp_error_msg[tmp];
}
if (msg) {
error_msg("server says: %s", msg);
}
break;
}
}
close(socketfd);
return finished ? EXIT_SUCCESS : EXIT_FAILURE;
}
int tftp_main(int argc, char **argv)
{
struct hostent *host = NULL;
char *localfile = NULL;
char *remotefile = NULL;
int port = 69;
int cmd = 0;
int fd = -1;
int flags = 0;
int opt;
int result;
int blocksize = 512;
while ((opt = getopt(argc, argv, "b:gpl:r:")) != -1) {
switch (opt) {
case 'b':
blocksize = atoi(optarg);
break;
#ifdef BB_FEATURE_TFTP_GET
case 'g':
cmd = tftp_cmd_get;
flags = O_WRONLY | O_CREAT;
break;
#endif
#ifdef BB_FEATURE_TFTP_PUT
case 'p':
cmd = tftp_cmd_put;
flags = O_RDONLY;
break;
#endif
case 'l':
localfile = xstrdup(optarg);
break;
case 'r':
remotefile = xstrdup(optarg);
break;
}
}
if ((cmd == 0) || (optind == argc)) {
show_usage();
}
fd = open(localfile, flags, 0644);
if (fd < 0) {
perror_msg_and_die("local file");
}
host = xgethostbyname(argv[optind]);
if (optind + 2 == argc) {
port = atoi(argv[optind + 1]);
}
#ifdef BB_FEATURE_TFTP_DEBUG
printf("using server \"%s\", serverfile \"%s\","
"localfile \"%s\".\n",
inet_ntoa(*((struct in_addr *) host->h_addr)),
remotefile, localfile);
#endif
result = tftp(cmd, host, remotefile, fd, port, blocksize);
close(fd);
return(result);
}
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