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tftp_file.c
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/* hey emacs! -*- Mode: C; c-file-style: "k&r"; indent-tabs-mode: nil -*- */
/*
* tftp_file.c
* client side file operations. File receiving and sending.
*
* $Id: tftp_file.c,v 1.42 2004/02/13 03:16:09 jp Exp $
*
* Copyright (c) 2000 Jean-Pierre Lefebvre <[email protected]>
* and Remi Lefebvre <[email protected]>
*
* atftp is free software; you can redistribute them and/or modify them
* 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.
*
*/
#include "config.h"
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <arpa/tftp.h>
#include <netdb.h>
#include <string.h>
#include <sys/stat.h>
#include "tftp.h"
#include "tftp_io.h"
#include "tftp_def.h"
#include "options.h"
#define S_BEGIN 0
#define S_SEND_REQ 1
#define S_SEND_ACK 2
#define S_SEND_OACK 3
#define S_SEND_DATA 4
#define S_WAIT_PACKET 5
#define S_REQ_RECEIVED 6
#define S_ACK_RECEIVED 7
#define S_OACK_RECEIVED 8
#define S_DATA_RECEIVED 9
#define S_ABORT 10
#define S_END 11
#define NB_BLOCK 2048
extern int tftp_cancel;
extern int tftp_prevent_sas;
/*
* Find a hole in the file bitmap.
*/
int tftp_find_bitmap_hole(int prev_hole, unsigned int *bitmap)
{
int next_hole, next_word_no, next_bit_no;
unsigned int next_word;
/* initial stuff */
next_hole = 0; /*prev_hole + 1;*/
next_word_no = next_hole / 32;
next_bit_no = next_hole % 32;
next_word = bitmap[next_word_no];
/* Check if there is a remainder of the current word to traverse */
if (next_bit_no != 0)
{
/* traverse remainder of word. We know that all previous
bits are set */
if (next_word == 0xffffffff)
{
next_bit_no = 0;
next_word_no++;
next_word = bitmap[next_word_no];
}
}
/* travserse whole words */
while ((next_word == 0xffffffff) && (next_word_no < NB_BLOCK))
{
next_word_no++;
next_word = bitmap[next_word_no];
}
/* find the bit */
next_word >>= next_bit_no;
while (next_word & 1)
{
next_bit_no++;
next_word >>= 1;
}
return (next_word_no * 32) + next_bit_no;
}
/*
* Receive a file. This is implemented as a state machine using a while loop
* and a switch statement. Function flow is as follow:
* - sanity check
* - enter state machine
*
* 1) send request
* 2) wait reply
* - if DATA packet, read it, send an acknoledge, goto 2
* - if OACK (option acknowledge) acknowledge this option, goto 2
* - if ERROR abort
* - if TIMEOUT goto previous state
*/
int tftp_receive_file(struct client_data *data)
{
int state = S_SEND_REQ; /* current state in the state machine */
int timeout_state = state; /* what state should we go on when timeout */
int windowblock = 0; /* number of block in a window, c.f. RFC7440 */
int windowsize = 1; /* c.f. RFC7440 */
int result;
long block_number = 0;
long last_received_block = 0;
long last_block_number = -1; /* block number of last block for multicast */
int extra_ack = 0; /* number of additional ACKs */
//int debug = 0; /* used for simulating datagram losses */
int data_size; /* size of data received */
int sockfd = data->sockfd; /* just to simplify calls */
struct sockaddr_storage sa; /* a copy of data.sa_peer */
struct sockaddr_storage from;
char from_str[SOCKADDR_PRINT_ADDR_LEN];
int connected; /* 1 when sockfd is connected */
struct tftphdr *tftphdr = (struct tftphdr *)data->data_buffer;
FILE *fp = NULL; /* the local file pointer */
int number_of_timeout = 0;
int convert = 0; /* if true, do netascii conversion */
int oacks = 0; /* count OACK for improved error checking */
int multicast = 0; /* set to 1 if multicast */
int mc_port; /* multicast port */
char mc_addr[IPADDRLEN]; /* multicast address */
int mcast_sockfd = 0;
struct addrinfo hints, *addrinfo;
struct sockaddr_storage sa_mcast_group;
struct sockaddr_storage sa_mcast;
union ip_mreq_storage mreq;
int master_client = 0;
unsigned int file_bitmap[NB_BLOCK];
int prev_bitmap_hole = -1; /* the previous hole found in the bitmap */
char string[MAXLEN];
long prev_block_number = 0; /* needed to support netascii conversion */
int temp = 0;
int err;
data->file_size = 0;
tftp_cancel = 0;
memset(&from, 0, sizeof(from));
memset(&sa_mcast_group, 0, sizeof(sa_mcast_group));
memset(&file_bitmap, 0, sizeof(file_bitmap));
/* make sure the socket is not connected */
sa.ss_family = AF_UNSPEC;
connect(sockfd, (struct sockaddr *)&sa, sizeof(sa));
connected = 0;
/* copy sa_peer structure */
memcpy(&sa, &data->sa_peer, sizeof(sa));
/* check to see if conversion is requiered */
if (strcasecmp(data->tftp_options[OPT_MODE].value, "netascii") == 0)
convert = 1;
/* make sure the data buffer is SEGSIZE + 4 bytes */
if (data->data_buffer_size != (SEGSIZE + 4))
{
data->data_buffer = realloc(data->data_buffer, SEGSIZE + 4);
tftphdr = (struct tftphdr *)data->data_buffer;
if (data->data_buffer == NULL)
{
fprintf(stderr, "tftp: memory allocation failure.\n");
exit(1);
}
data->data_buffer_size = SEGSIZE + 4;
}
/* open the file for writing */
if ((fp = fopen(data->local_file, "w")) == NULL)
{
fprintf(stderr, "tftp: can't open %s for writing.\n",
data->local_file);
return ERR;
}
while (1)
{
#ifdef DEBUG
if (data->delay)
usleep(data->delay*1000);
#endif
if (tftp_cancel)
{
if (from.ss_family == 0)
state = S_ABORT;
else
{
tftp_send_error(sockfd, &sa, EUNDEF, data->data_buffer,
data->data_buffer_size);
if (data->trace)
fprintf(stderr, "sent ERROR <code: %d, msg: %s>\n",
EUNDEF, tftp_errmsg[EUNDEF]);
state = S_ABORT;
}
tftp_cancel = 0;
}
switch (state)
{
case S_SEND_REQ:
timeout_state = S_SEND_REQ;
if (data->trace)
{
opt_options_to_string(data->tftp_options, string, MAXLEN);
fprintf(stderr, "sent RRQ <file: %s, mode: %s <%s>>\n",
data->tftp_options[OPT_FILENAME].value,
data->tftp_options[OPT_MODE].value,
string);
}
sockaddr_set_port(&sa, sockaddr_get_port(&data->sa_peer));
/* send request packet */
if (tftp_send_request(sockfd, &sa, RRQ, data->data_buffer,
data->data_buffer_size,
data->tftp_options) == ERR)
state = S_ABORT;
else
state = S_WAIT_PACKET;
sockaddr_set_port(&sa, 0); /* must be set to 0 before the fist call to
tftp_get_packet, but is was set before the
call to tftp_send_request */
break;
case S_SEND_ACK:
windowblock = 0;
timeout_state = S_SEND_ACK;
if (multicast)
{
/* walk the bitmap to find the next missing block */
prev_bitmap_hole =
tftp_find_bitmap_hole(prev_bitmap_hole, file_bitmap);
block_number = last_received_block = prev_bitmap_hole;
}
/* This might be used for simulating a lost ACK (with windowsize=32):
if ((last_received_block != 320) || (debug != 0)) {
tftp_send_ack(sockfd, &sa, last_received_block);
} else {
debug++;
}
Comment the next line if debugging is activated! */
tftp_send_ack(sockfd, &sa, last_received_block);
if (data->trace)
fprintf(stderr, "sent ACK <block: %ld>\n", last_received_block);
/* if we just ACK the last block we are done */
if (block_number == last_block_number)
state = S_END;
else
state = S_WAIT_PACKET;
break;
case S_WAIT_PACKET:
data_size = data->data_buffer_size;
if (multicast)
{
result = tftp_get_packet(sockfd, mcast_sockfd, NULL, &sa, &from,
NULL, data->timeout, 0, &data_size,
data->data_buffer);
/* RFC2090 state we should verify source address as well
as source port */
if (!sockaddr_equal(&sa, &from))
{
result = GET_DISCARD;
fprintf(stderr, "source address or port mismatch\n");
}
}
else
{
result = tftp_get_packet(sockfd, -1, NULL, &sa, &from, NULL,
data->timeout, 0, &data_size,
data->data_buffer);
/* Check that source port match */
if ((sockaddr_get_port(&sa) != sockaddr_get_port(&from)) &&
((result == GET_OACK) || (result == GET_ERROR) ||
(result == GET_DATA)))
{
if (data->checkport)
{
result = GET_DISCARD;
fprintf(stderr, "source port mismatch\n");
}
else
fprintf(stderr, "source port mismatch, check bypassed");
}
}
switch (result)
{
case GET_TIMEOUT:
number_of_timeout++;
extra_ack = 0;
fprintf(stderr, "timeout: retrying ...\n");
if (number_of_timeout > NB_OF_RETRY)
state = S_ABORT;
else
state = timeout_state;
break;
case GET_OACK:
number_of_timeout = 0;
/* if the socket if not connected, connect it */
if (!connected)
{
connect(sockfd, (struct sockaddr *)&sa, sizeof(sa));
connected = 1;
}
state = S_OACK_RECEIVED;
break;
case GET_ERROR:
fprintf(stderr, "tftp: error received from server <");
fwrite(tftphdr->th_msg, 1, data_size - 4 - 1, stderr);
fprintf(stderr, ">\n");
state = S_ABORT;
break;
case GET_DATA:
number_of_timeout = 0;
/* if the socket if not connected, connect it */
if (!connected)
{
connect(sockfd, (struct sockaddr *)&sa, sizeof(sa));
connected = 1;
}
state = S_DATA_RECEIVED;
break;
case GET_DISCARD:
/* consider discarded packet as timeout to make sure when don't
lock up when doing multicast transfer and routing is broken */
number_of_timeout++;
fprintf(stderr, "tftp: packet discard <%s:%d>.\n",
sockaddr_print_addr(&from, from_str, sizeof(from_str)),
sockaddr_get_port(&from));
if (number_of_timeout > NB_OF_RETRY)
state = S_ABORT;
break;
case ERR:
fprintf(stderr, "tftp: unknown error.\n");
state = S_ABORT;
break;
default:
fprintf(stderr, "tftp: abnormal return value %d.\n",
result);
}
break;
case S_OACK_RECEIVED:
oacks++;
if (multicast)
{
/* This is not the first oack. From the RFC, I don't think
it is illegal to receive many OACK. Need to check more
into that, but server may send us an OACK with mc=0 anytime */
#if 0
/* If we are a master, it is abnormal to receive again
* an OACK. We should terminate the file transfer of we'll
* timeout and exit.
*/
if (master_client == 1)
{
tftp_send_error(sockfd, &sa, EUNDEF, data->data_buffer,
data->data_buffer_size);
fprintf(stderr, "tftp: unexpected OACK\n");
state = S_ABORT;
break;
}
#endif
/* parse OACK options */
opt_parse_options(data->data_buffer, data_size,
data->tftp_options_reply);
if ((result = opt_get_multicast(data->tftp_options_reply,
mc_addr, &mc_port,
&master_client)) > -1)
if (master_client == 1)
{
if (data->trace)
fprintf(stderr, "received OACK <mc = 1>\n");
state = S_SEND_ACK;
}
else
{
if (data->trace)
fprintf(stderr, "received OACK <mc = 0>\n");
state = S_WAIT_PACKET;
}
else
{
tftp_send_error(sockfd, &sa, EUNDEF, data->data_buffer,
data->data_buffer_size);
fprintf(stderr, "tftp: error parsing OACK\n");
state = S_ABORT;
}
break;
}
else
{
/* Normally we shouldn't receive more than one OACK
in non-multicast mode. */
if (oacks > 1)
{
tftp_send_error(sockfd, &sa, EUNDEF, data->data_buffer,
data->data_buffer_size);
fprintf(stderr, "tftp: unexpected OACK\n");
state = S_ABORT;
break;
}
/* clean the tftp_options structure */
memcpy(data->tftp_options_reply, tftp_default_options,
sizeof(tftp_default_options));
/*
* look in the returned string for tsize, timeout,
* blksize, windowsize or multicast
*/
opt_disable_options(data->tftp_options_reply, NULL);
opt_parse_options(data->data_buffer, data_size,
data->tftp_options_reply);
if (data->trace)
fprintf(stderr, "received OACK <");
/* tsize: funny, now we know the file size */
if ((result = opt_get_tsize(data->tftp_options_reply)) > -1)
{
if (data->trace)
fprintf(stderr, "tsize: %d, ", result);
}
/* windowsize */
if ((result = opt_get_windowsize(data->tftp_options_reply)) > -1)
{
if (data->trace)
fprintf(stderr, "windowsize: %d, ", result);
windowsize = result;
}
/* timeout */
if ((result = opt_get_timeout(data->tftp_options_reply)) > -1)
{
if (data->trace)
fprintf(stderr, "timeout: %d, ", result);
}
/* blksize: resize the buffer please */
if ((result = opt_get_blksize(data->tftp_options_reply)) > -1)
{
if (data->trace)
fprintf(stderr, "blksize: %d, ", result);
data->data_buffer = realloc(data->data_buffer, result + 4);
tftphdr = (struct tftphdr *)data->data_buffer;
if (data->data_buffer == NULL)
{
fprintf(stderr,
"tftp: memory allocation failure.\n");
exit(1);
}
data->data_buffer_size = result + 4;
}
/* multicast: yish, it's more complex. If we are a master,
we are responsible to ask packet with an ACK. If we are
not master, then just receive packets. Missing packets
will be asked when we become a master client. Also we
can receive data in any order, with hole. The option
reply contain the new address and port to listen to.*/
if ((result = opt_get_multicast(data->tftp_options_reply,
mc_addr, &mc_port,
&master_client)) > -1)
{
if (data->trace)
fprintf(stderr, "multicast: %s,%d,%d, ", mc_addr,
mc_port, master_client);
/* look up the host */
/* if valid, update s_inn structure */
memset(&hints, 0, sizeof(hints));
hints.ai_socktype = SOCK_DGRAM;
if (!getaddrinfo(mc_addr, NULL, &hints, &addrinfo) &&
!sockaddr_set_addrinfo(&sa_mcast_group, addrinfo))
{
if (!sockaddr_is_multicast(&sa_mcast_group))
{
fprintf(stderr,
"atftp: bad multicast address %s\n",
mc_addr);
exit(1);
}
freeaddrinfo(addrinfo);
}
else
{
fprintf(stderr, "tftp: bad multicast address %s",
mc_addr);
exit(1);
}
/* we need to open a new socket for multicast */
if ((mcast_sockfd = socket(sa_mcast_group.ss_family,
SOCK_DGRAM, 0))<0)
{
fprintf(stderr,
"atftp: unable to open socket\n");
exit(1);
}
memset(&sa_mcast, 0, sizeof(sa_mcast));
sa_mcast.ss_family = sa_mcast_group.ss_family;
sockaddr_set_port(&sa_mcast, mc_port);
if (bind(mcast_sockfd, (struct sockaddr *)&sa_mcast,
sizeof(sa_mcast)) < 0)
{
perror("bind"); /* FIXME */
exit(1);
}
sockaddr_get_mreq(&sa_mcast_group, &mreq);
if (sa_mcast_group.ss_family == AF_INET)
err = setsockopt(mcast_sockfd, IPPROTO_IP,
IP_ADD_MEMBERSHIP,
&mreq.v4, sizeof(mreq.v4));
else
err = setsockopt(mcast_sockfd, IPPROTO_IPV6,
IPV6_ADD_MEMBERSHIP,
&mreq.v6, sizeof(mreq.v6));
if (err < 0)
{
perror("setsockopt");
exit(1);
}
multicast = 1;
}
}
if (data->trace)
fprintf(stderr, "\b\b>\n");
if ((multicast && master_client) || (!multicast))
state = S_SEND_ACK;
else
state = S_WAIT_PACKET;
break;
case S_DATA_RECEIVED:
if (multicast)
block_number = ntohs(tftphdr->th_block);
else
block_number = tftp_rollover_blocknumber(ntohs(tftphdr->th_block), prev_block_number, 0);
if ((last_received_block < windowsize) && (timeout_state = S_SEND_OACK))
timeout_state = S_SEND_ACK;
if ((!multicast) || (multicast && master_client)) {
timeout_state = S_SEND_ACK;
/* The sequence of blocks may contain a gap, i.e. (block_number > last_received_block + 1).
Send an extra ACK for the last block before the gap once.
The ACK of a received window gets lost. The sender times out and starts
sending all blocks of that window again, i.e. (block_number < last_received_block + 1).
Again, send the extra ACK. */
if (block_number != last_received_block + 1) {
if (extra_ack < 1) {
fprintf(stderr, "got wrong block <block: %ld>, sending extra ACK for <block: %ld>\n",
block_number, last_received_block);
extra_ack++;
state = S_SEND_ACK;
} else {
fprintf(stderr, "got wrong block <block: %ld>, ignoring\n", block_number);
state = S_WAIT_PACKET;
}
break;
}
extra_ack = 0;
windowblock++;
} else {
timeout_state = S_WAIT_PACKET;
}
if (data->trace)
fprintf(stderr, "received %d. DATA <block: %ld, size %d>, update last received block: %ld → %ld\n",
windowblock, block_number, data_size - 4, last_received_block, block_number);
last_received_block = block_number;
if (tftp_file_write(fp, tftphdr->th_data, data->data_buffer_size - 4, block_number,
data_size - 4, convert, &prev_block_number, &temp) != data_size - 4)
{
fprintf(stderr, "tftp: error writing to file %s\n",
data->local_file);
tftp_send_error(sockfd, &sa, ENOSPACE, data->data_buffer,
data->data_buffer_size);
state = S_ABORT;
break;
}
data->file_size += data_size;
/* Record the block number of the last block. The last block
is the one with less data than the transfer block size */
if (data_size < data->data_buffer_size)
last_block_number = block_number;
if (multicast)
{
/* Mark the received block in the bitmap */
file_bitmap[(block_number - 1)/32]
|= (1 << ((block_number - 1) % 32));
/* if we are the master client we ack, else
we just wait for data */
if (master_client || !multicast) // FIXME
state = S_SEND_ACK;
else
state = S_WAIT_PACKET;
}
else
{
if ((windowblock >= windowsize) || (last_block_number != -1))
state = S_SEND_ACK;
else
state = S_WAIT_PACKET;
}
break;
case S_END:
case S_ABORT:
/* close file */
if (fp)
fclose(fp);
/* drop multicast membership */
if (multicast)
{
if (sa_mcast_group.ss_family == AF_INET)
err = setsockopt(mcast_sockfd, IPPROTO_IP,
IP_DROP_MEMBERSHIP,
&mreq.v4, sizeof(mreq.v4));
else
err = setsockopt(mcast_sockfd, IPPROTO_IPV6,
IPV6_DROP_MEMBERSHIP,
&mreq.v6, sizeof(mreq.v6));
if (err < 0)
{
perror("setsockopt");
exit(1);
}
}
/* close multicast socket */
if (mcast_sockfd)
close(mcast_sockfd);
/* return proper error code */
if (state == S_END)
return OK;
else
fprintf(stderr, "tftp: aborting\n");
default:
return ERR;
}
}
}
/*
* Send a file. This is implemented as a state machine using a while loop
* and a switch statement. Function flow is as follow:
* - sanity check
* - enter state machine
*
* 1) send request
* 2) wait replay
* - if ACK, goto 3
* - if OACK (option acknowledge) acknowledge this option, goto 2
* - if ERROR abort
* - if TIMEOUT goto previous state
* 3) send data, goto 2
*/
int tftp_send_file(struct client_data *data)
{
int state = S_SEND_REQ; /* current state in the state machine */
int timeout_state = state; /* what state should we go on when timeout */
int windowblock = 0; /* number of block in a window, c.f. RFC7440 */
int windowsize = 1; /* c.f. RFC7440 */
int delay = 0; /* delay between datagrams in a window */
int result;
long block_number = 0;
long last_requested_block = -1;
long last_block = -1;
int data_size; /* size of data received */
int sockfd = data->sockfd; /* just to simplify calls */
struct sockaddr_storage sa; /* a copy of data.sa_peer */
struct sockaddr_storage from;
char from_str[SOCKADDR_PRINT_ADDR_LEN];
int connected; /* 1 when sockfd is connected */
struct tftphdr *tftphdr = (struct tftphdr *)data->data_buffer;
FILE *fp; /* the local file pointer */
int number_of_timeout = 0;
struct stat file_stat;
int convert = 0; /* if true, do netascii conversion */
char string[MAXLEN];
long prev_block_number = 0; /* needed to support netascii conversion */
long prev_file_pos = 0;
int temp = 0;
data->file_size = 0;
tftp_cancel = 0;
memset(&from, 0, sizeof(from));
/* make sure the socket is not connected */
sa.ss_family = AF_UNSPEC;
connect(sockfd, (struct sockaddr *)&sa, sizeof(sa));
connected = 0;
/* copy sa_peer structure */
memcpy(&sa, &data->sa_peer, sizeof(sa));
/* check to see if conversion is requiered */
if (strcasecmp(data->tftp_options[OPT_MODE].value, "netascii") == 0)
convert = 1;
/* make sure the data buffer is SEGSIZE + 4 bytes */
if (data->data_buffer_size != (SEGSIZE + 4))
{
data->data_buffer = realloc(data->data_buffer, SEGSIZE + 4);
tftphdr = (struct tftphdr *)data->data_buffer;
if (data->data_buffer == NULL)
{
fprintf(stderr, "tftp: memory allocation failure.\n");
exit(1);
}
data->data_buffer_size = SEGSIZE + 4;
}
/* open the file for reading */
if ((fp = fopen(data->local_file, "r")) == NULL)
{
fprintf(stderr, "tftp: can't open %s for reading.\n",
data->local_file);
return ERR;
}
/* When sending a file with the tsize argument, we shall
put the file size as argument */
fstat(fileno(fp), &file_stat);
if (opt_get_tsize(data->tftp_options) > -1)
opt_set_tsize(file_stat.st_size, data->tftp_options);
while (1)
{
#ifdef DEBUG
if (data->delay)
usleep(data->delay*1000);
#endif
if (tftp_cancel)
{
/* Make sure we know the peer's address */
if (from.ss_family == 0)
state = S_ABORT;
else
{
tftp_send_error(sockfd, &sa, EUNDEF, data->data_buffer,
data->data_buffer_size);
if (data->trace)
fprintf(stderr, "sent ERROR <code: %d, msg: %s>\n",
EUNDEF, tftp_errmsg[EUNDEF]);
state = S_ABORT;
}
tftp_cancel = 0;
}
switch (state)
{
case S_SEND_REQ:
timeout_state = S_SEND_REQ;
if (data->trace)
{
opt_options_to_string(data->tftp_options, string, MAXLEN);
fprintf(stderr, "sent WRQ <file: %s, mode: %s <%s>>\n",
data->tftp_options[OPT_FILENAME].value,
data->tftp_options[OPT_MODE].value,
string);
}
sockaddr_set_port(&sa, sockaddr_get_port(&data->sa_peer));
/* send request packet */
if (tftp_send_request(sockfd, &sa, WRQ, data->data_buffer,
data->data_buffer_size,
data->tftp_options) == ERR)
state = S_ABORT;
else
state = S_WAIT_PACKET;
sockaddr_set_port(&sa, 0); /* must be set to 0 before the fist call to
tftp_get_packet, but is was set before the
call to tftp_send_request */
break;
case S_SEND_DATA:
timeout_state = S_SEND_DATA;
data_size = tftp_file_read(fp, tftphdr->th_data, data->data_buffer_size - 4, block_number,
convert, &prev_block_number, &prev_file_pos, &temp);
data_size += 4; /* need to consider tftp header */
tftp_send_data(sockfd, &sa, block_number + 1,
data_size, data->data_buffer);
data->file_size += data_size;
windowblock++;
if (data->trace)
fprintf(stderr, "sent %d. DATA <block: %ld, size %d>\n",
windowblock, block_number + 1, data_size - 4);
state = S_WAIT_PACKET;
if (feof(fp))
last_block = block_number;
else
block_number = tftp_rollover_blocknumber(
ntohs(tftphdr->th_block), prev_block_number, 0);
break;
case S_WAIT_PACKET:
data_size = data->data_buffer_size;
if ((windowblock >= windowsize) || (block_number == 0) || (last_block != -1))
{
windowblock = 0;
/* we wait for the ACK */
result = tftp_get_packet(sockfd, -1, NULL, &sa, &from, NULL,
data->timeout, 0, &data_size, data->data_buffer);
}
else
{
/* we check if an unsolicitated ACK arrived */
result = tftp_get_packet(sockfd, -1, NULL, &sa, &from, NULL,
0, delay, &data_size, data->data_buffer);
if (result == GET_TIMEOUT)
{
/* we send the next block */
state = S_SEND_DATA;
break;
}
}
/* check that source port match */
if (sockaddr_get_port(&sa) != sockaddr_get_port(&from))
{
if ((data->checkport) &&
((result == GET_ACK) || (result == GET_OACK) ||
(result == GET_ERROR)))
result = GET_DISCARD;
else
fprintf(stderr, "source port mismatch, check bypassed");
}
switch (result)
{
case GET_TIMEOUT:
number_of_timeout++;
fprintf(stderr, "timeout: retrying ...\n");
if (number_of_timeout > NB_OF_RETRY)
state = S_ABORT;
else
state = timeout_state;
break;
case GET_ACK:
number_of_timeout = 0;
windowblock = 0;
/* if the socket if not connected, connect it */
if (!connected)
{
//connect(sockfd, (struct sockaddr *)&sa, sizeof(sa));
connected = 1;
}
block_number = tftp_rollover_blocknumber(
ntohs(tftphdr->th_block), prev_block_number, 0);
// The last block has been sent, but not received. Reset last_block:
if (block_number < last_block) last_block = -1;
/* if turned on, check whether the block request isn't already fulfilled */
if (tftp_prevent_sas) {
if (last_requested_block >= block_number) {
if (data->trace)
fprintf(stderr, "received duplicated ACK <block: %ld >= %ld>\n",
last_requested_block, block_number);
break;
} else
last_requested_block = block_number;
}
if (data->trace)
fprintf(stderr, "received ACK <block: %ld>\n",
block_number);
if ((last_block != -1) && (block_number > last_block))
{
state = S_END;
break;
}
state = S_SEND_DATA;
break;
case GET_OACK:
number_of_timeout = 0;
/* if the socket if not connected, connect it */
if (!connected)
{
//connect(sockfd, (struct sockaddr *)&sa, sizeof(sa));
connected = 1;
}
state = S_OACK_RECEIVED;
break;
case GET_ERROR:
fprintf(stderr, "tftp: error received from server <");
fwrite(tftphdr->th_msg, 1, data_size - 4 - 1, stderr);
fprintf(stderr, ">\n");
state = S_ABORT;
break;
case GET_DISCARD:
/* consider discarded packet as timeout to make sure when don't lock up
if routing is broken */
number_of_timeout++;
fprintf(stderr, "tftp: packet discard <%s:%d>.\n",
sockaddr_print_addr(&from, from_str, sizeof(from_str)),
sockaddr_get_port(&from));
if (number_of_timeout > NB_OF_RETRY)
state = S_ABORT;
break;
case ERR:
fprintf(stderr, "tftp: unknown error.\n");
state = S_ABORT;
break;
default:
fprintf(stderr, "tftp: abnormal return value %d.\n",
result);
}
break;
case S_OACK_RECEIVED:
/* clean the tftp_options structure */
memcpy(data->tftp_options_reply, tftp_default_options,
sizeof(tftp_default_options));
/*
* look in the returned string for tsize, timeout, blksize or
* multicast
*/
opt_disable_options(data->tftp_options_reply, NULL);
opt_parse_options(data->data_buffer, data_size,
data->tftp_options_reply);
if (data->trace)
fprintf(stderr, "received OACK <");
/* tsize: funny, now we know the file size */
if ((result = opt_get_tsize(data->tftp_options_reply)) > -1)
{
if (data->trace)
fprintf(stderr, "tsize: %d, ", result);
}
/* windowsize */
if ((result = opt_get_windowsize(data->tftp_options_reply)) > -1)
{
if (data->trace)
fprintf(stderr, "windowsize: %d, ", result);
windowsize = result;
}
/* timeout */
if ((result = opt_get_timeout(data->tftp_options_reply)) > -1)
{
if (data->trace)
fprintf(stderr, "timeout: %d, ", result);
}
/* blksize: resize the buffer please */
if ((result = opt_get_blksize(data->tftp_options_reply)) > -1)
{
if (data->trace)
fprintf(stderr, "blksize: %d, ", result);
data->data_buffer = realloc(data->data_buffer,
result + 4);
tftphdr = (struct tftphdr *)data->data_buffer;
if (data->data_buffer == NULL)
{
fprintf(stderr,
"tftp: memory allocation failure.\n");
exit(1);
}
data->data_buffer_size = result + 4;
}
/* multicast: yish, it's more complex. If we are a master,
we are responsible to ask packet with an ACK. If we are
not master, then just receive packets. Missing packets
will be asked when we become a master client */
if (data->trace)
fprintf(stderr, "\b\b>\n");
state = S_SEND_DATA;
break;
case S_END:
if (fp)
fclose(fp);
return OK;
break;
case S_ABORT:
if (fp)
fclose(fp);
fprintf(stderr, "tftp: aborting\n");
default:
return ERR;
}
}
}