Add TFTP client as specified by RFC 1350
This client does not support the netascii mode. The default mode is octet/binary and should be sufficient. One thing left to do is to check the source port of the server to make sure it doesn't change. If it does, we should ignore the packet and send an error back without disturbing an existing transfer.
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sin
parent
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1
README
1
README
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@ -78,6 +78,7 @@ The following tools are implemented:
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=*|x tar .
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=*|o tee .
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=*|o test .
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=* x tftp .
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=*|o time .
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=*|o touch .
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#*|o tr .
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29
tftp.1
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29
tftp.1
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@ -0,0 +1,29 @@
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.Dd August 14, 2015
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.Dt TFTP 1
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.Os sbase
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.Sh NAME
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.Nm tftp
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.Nd trivial file transfer protocol client
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.Sh SYNOPSIS
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.Nm
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.Fl h Ar host
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.Op Fl p Ar port
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.Op Fl x | c
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.Ar file
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.Sh DESCRIPTION
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.Nm
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is a client that implements the trivial file transfer protocol over
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either IPv4 or IPv6 as specified in RFC 1350. It can be used to transfer
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files to and from remote machines.
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.Sh OPTIONS
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.Bl -tag -width Ds
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.It Fl h Ar host
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Set the remote hostname.
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.It Fl p Ar port
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Set the remote port. It defaults to port 69.
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.It Fl x
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Extract a file from the server. This is the default
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if no flags are specified. Output goes to stdout.
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.It Fl c
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Create a file on the server. Input comes from stdin.
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.El
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308
tftp.c
Normal file
308
tftp.c
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@ -0,0 +1,308 @@
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/* See LICENSE file for copyright and license details. */
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <netdb.h>
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#include <netinet/in.h>
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "util.h"
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#define BLKSIZE 512
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#define HDRSIZE 4
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#define PKTSIZE (BLKSIZE + HDRSIZE)
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#define TIMEOUT_SEC 5
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/* transfer will time out after NRETRIES * TIMEOUT_SEC */
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#define NRETRIES 5
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#define RRQ 1
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#define WWQ 2
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#define DATA 3
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#define ACK 4
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#define ERR 5
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static char *errtext[] = {
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"Undefined",
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"File not found",
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"Access violation",
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"Disk full or allocation exceeded",
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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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static struct sockaddr_storage to;
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static socklen_t tolen;
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static int timeout;
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static int state;
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static int s;
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static int
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packreq(unsigned char *buf, int op, char *path, char *mode)
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{
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unsigned char *p = buf;
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*p++ = op >> 8;
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*p++ = op & 0xff;
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if (strlen(path) + 1 > 256)
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eprintf("filename too long\n");
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memcpy(p, path, strlen(path) + 1);
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p += strlen(path) + 1;
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memcpy(p, mode, strlen(mode) + 1);
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p += strlen(mode) + 1;
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return p - buf;
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}
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static int
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packack(unsigned char *buf, int blkno)
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{
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buf[0] = ACK >> 8;
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buf[1] = ACK & 0xff;
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buf[2] = blkno >> 8;
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buf[3] = blkno & 0xff;
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return 4;
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}
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static int
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packdata(unsigned char *buf, int blkno)
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{
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buf[0] = DATA >> 8;
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buf[1] = DATA & 0xff;
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buf[2] = blkno >> 8;
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buf[3] = blkno & 0xff;
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return 4;
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}
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static int
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unpackop(unsigned char *buf)
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{
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return (buf[0] << 8) | (buf[1] & 0xff);
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}
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static int
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unpackblkno(unsigned char *buf)
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{
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return (buf[2] << 8) | (buf[3] & 0xff);
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}
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static int
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unpackerrc(unsigned char *buf)
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{
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int errc;
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errc = (buf[2] << 8) | (buf[3] & 0xff);
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if (errc < 0 || errc >= LEN(errtext))
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eprintf("bad error code: %d\n", errc);
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return errc;
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}
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static int
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writepkt(unsigned char *buf, int len)
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{
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int n;
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n = sendto(s, buf, len, 0, (struct sockaddr *)&to,
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tolen);
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if (n < 0)
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if (errno != EINTR)
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eprintf("sendto:");
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return n;
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}
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static int
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readpkt(unsigned char *buf, int len)
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{
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int n;
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n = recvfrom(s, buf, len, 0, (struct sockaddr *)&to,
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&tolen);
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if (n < 0) {
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if (errno != EINTR && errno != EWOULDBLOCK)
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eprintf("recvfrom:");
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timeout++;
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if (timeout == NRETRIES)
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eprintf("transfer timed out\n");
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} else {
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timeout = 0;
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}
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return n;
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}
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static void
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getfile(char *file)
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{
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unsigned char buf[PKTSIZE];
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int n, op, blkno, nextblkno = 1, done = 0;
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state = RRQ;
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for (;;) {
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switch (state) {
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case RRQ:
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n = packreq(buf, RRQ, file, "octet");
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writepkt(buf, n);
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n = readpkt(buf, sizeof(buf));
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if (n > 0) {
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op = unpackop(buf);
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if (op != DATA && op != ERR)
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eprintf("bad opcode: %d\n", op);
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state = op;
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}
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break;
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case DATA:
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n -= HDRSIZE;
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if (n < 0)
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eprintf("truncated packet\n");
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blkno = unpackblkno(buf);
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if (blkno == nextblkno) {
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nextblkno++;
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write(1, &buf[HDRSIZE], n);
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}
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if (n < BLKSIZE)
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done = 1;
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state = ACK;
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break;
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case ACK:
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n = packack(buf, blkno);
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writepkt(buf, n);
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if (done)
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return;
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n = readpkt(buf, sizeof(buf));
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if (n > 0) {
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op = unpackop(buf);
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if (op != DATA && op != ERR)
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eprintf("bad opcode: %d\n", op);
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state = op;
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}
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break;
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case ERR:
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eprintf("error: %s\n", errtext[unpackerrc(buf)]);
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}
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}
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}
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static void
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putfile(char *file)
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{
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unsigned char inbuf[PKTSIZE], outbuf[PKTSIZE];
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int inb, outb, op, blkno, nextblkno = 0, done = 0;
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state = WWQ;
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for (;;) {
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switch (state) {
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case WWQ:
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outb = packreq(outbuf, WWQ, file, "octet");
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writepkt(outbuf, outb);
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inb = readpkt(inbuf, sizeof(inbuf));
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if (inb > 0) {
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op = unpackop(inbuf);
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if (op != ACK && op != ERR)
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eprintf("bad opcode: %d\n", op);
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state = op;
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}
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break;
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case DATA:
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if (blkno == nextblkno) {
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nextblkno++;
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packdata(outbuf, nextblkno);
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outb = read(0, &outbuf[HDRSIZE], BLKSIZE);
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if (outb < BLKSIZE)
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done = 1;
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}
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writepkt(outbuf, outb + HDRSIZE);
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inb = readpkt(inbuf, sizeof(inbuf));
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if (inb > 0) {
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op = unpackop(inbuf);
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if (op != ACK && op != ERR)
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eprintf("bad opcode: %d\n", op);
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state = op;
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}
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break;
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case ACK:
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if (inb < HDRSIZE)
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eprintf("truncated packet\n");
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blkno = unpackblkno(inbuf);
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if (blkno == nextblkno)
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if (done)
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return;
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state = DATA;
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break;
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case ERR:
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eprintf("error: %s\n", errtext[unpackerrc(inbuf)]);
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}
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}
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}
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static void
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usage(void)
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{
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eprintf("usage: %s -h host [-p port] [-x | -c] file\n", argv0);
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}
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int
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main(int argc, char *argv[])
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{
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struct addrinfo hints, *res, *r;
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struct timeval tv;
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char *host = NULL, *port = "tftp";
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void (*fn)(char *) = getfile;
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int ret;
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ARGBEGIN {
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case 'h':
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host = EARGF(usage());
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break;
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case 'p':
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port = EARGF(usage());
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break;
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case 'x':
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fn = getfile;
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break;
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case 'c':
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fn = putfile;
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break;
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default:
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usage();
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} ARGEND;
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if (!host || !argc)
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usage();
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memset(&hints, 0, sizeof(hints));
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hints.ai_family = AF_UNSPEC;
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hints.ai_socktype = SOCK_DGRAM;
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hints.ai_protocol = IPPROTO_UDP;
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ret = getaddrinfo(host, port, &hints, &res);
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if (ret)
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eprintf("getaddrinfo: %s\n", gai_strerror(ret));
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for (r = res; r; r = r->ai_next) {
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if (r->ai_family != AF_INET &&
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r->ai_family != AF_INET6)
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continue;
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s = socket(r->ai_family, r->ai_socktype,
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r->ai_protocol);
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if (s < 0)
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continue;
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break;
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}
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if (!r)
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eprintf("cannot create socket\n");
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memcpy(&to, r->ai_addr, r->ai_addrlen);
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tolen = r->ai_addrlen;
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freeaddrinfo(res);
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tv.tv_sec = TIMEOUT_SEC;
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tv.tv_usec = 0;
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if (setsockopt(s, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)) < 0)
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eprintf("setsockopt:");
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fn(argv[0]);
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return 0;
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}
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