471 lines
11 KiB
C
471 lines
11 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (C) 2008 Edwin Groothuis. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <sys/stat.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <arpa/tftp.h>
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#include <assert.h>
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#include <errno.h>
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#include <setjmp.h>
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#include <signal.h>
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#include <stddef.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 <syslog.h>
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#include <unistd.h>
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#include "tftp-file.h"
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#include "tftp-io.h"
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#include "tftp-utils.h"
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#include "tftp-options.h"
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struct sockaddr_storage peer_sock;
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struct sockaddr_storage me_sock;
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static int send_packet(int peer, uint16_t block, char *pkt, int size);
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static struct errmsg {
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int e_code;
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const char *e_msg;
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} errmsgs[] = {
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{ EUNDEF, "Undefined error code" },
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{ ENOTFOUND, "File not found" },
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{ EACCESS, "Access violation" },
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{ ENOSPACE, "Disk full or allocation exceeded" },
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{ EBADOP, "Illegal TFTP operation" },
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{ EBADID, "Unknown transfer ID" },
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{ EEXISTS, "File already exists" },
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{ ENOUSER, "No such user" },
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{ EOPTNEG, "Option negotiation" },
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{ -1, NULL }
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};
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#define DROPPACKET(s) \
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if (packetdroppercentage != 0 && \
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random()%100 < packetdroppercentage) { \
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tftp_log(LOG_DEBUG, "Artificial packet drop in %s", s); \
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return; \
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}
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#define DROPPACKETn(s,n) \
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if (packetdroppercentage != 0 && \
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random()%100 < packetdroppercentage) { \
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tftp_log(LOG_DEBUG, "Artificial packet drop in %s", s); \
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return (n); \
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}
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const char *
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errtomsg(int error)
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{
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static char ebuf[40];
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struct errmsg *pe;
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if (error == 0)
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return ("success");
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for (pe = errmsgs; pe->e_code >= 0; pe++)
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if (pe->e_code == error)
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return (pe->e_msg);
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snprintf(ebuf, sizeof(ebuf), "error %d", error);
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return (ebuf);
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}
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static int
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send_packet(int peer, uint16_t block, char *pkt, int size)
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{
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int i;
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int t = 1;
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for (i = 0; i < 12 ; i++) {
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DROPPACKETn("send_packet", 0);
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if (sendto(peer, pkt, size, 0, (struct sockaddr *)&peer_sock,
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peer_sock.ss_len) == size) {
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if (i)
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tftp_log(LOG_ERR,
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"%s block %d, attempt %d successful",
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packettype(ntohs(((struct tftphdr *)
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(pkt))->th_opcode)), block, i);
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return (0);
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}
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tftp_log(LOG_ERR,
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"%s block %d, attempt %d failed (Error %d: %s)",
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packettype(ntohs(((struct tftphdr *)(pkt))->th_opcode)),
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block, i, errno, strerror(errno));
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sleep(t);
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if (t < 32)
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t <<= 1;
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}
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tftp_log(LOG_ERR, "send_packet: %s", strerror(errno));
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return (1);
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}
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/*
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* Send an ERROR packet (error message).
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* Error code passed in is one of the
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* standard TFTP codes, or a UNIX errno
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* offset by 100.
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*/
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void
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send_error(int peer, int error)
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{
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struct tftphdr *tp;
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int length;
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struct errmsg *pe;
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char buf[MAXPKTSIZE];
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if (debug & DEBUG_PACKETS)
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tftp_log(LOG_DEBUG, "Sending ERROR %d", error);
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DROPPACKET("send_error");
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tp = (struct tftphdr *)buf;
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tp->th_opcode = htons((u_short)ERROR);
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tp->th_code = htons((u_short)error);
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for (pe = errmsgs; pe->e_code >= 0; pe++)
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if (pe->e_code == error)
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break;
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if (pe->e_code < 0) {
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pe->e_msg = strerror(error - 100);
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tp->th_code = EUNDEF; /* set 'undef' errorcode */
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}
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strcpy(tp->th_msg, pe->e_msg);
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length = strlen(pe->e_msg);
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tp->th_msg[length] = '\0';
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length += 5;
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if (debug & DEBUG_PACKETS)
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tftp_log(LOG_DEBUG, "Sending ERROR %d: %s", error, tp->th_msg);
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if (sendto(peer, buf, length, 0,
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(struct sockaddr *)&peer_sock, peer_sock.ss_len) != length)
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tftp_log(LOG_ERR, "send_error: %s", strerror(errno));
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}
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/*
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* Send an WRQ packet (write request).
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*/
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int
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send_wrq(int peer, char *filename, char *mode)
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{
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int n;
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struct tftphdr *tp;
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char *bp;
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char buf[MAXPKTSIZE];
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int size;
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if (debug & DEBUG_PACKETS)
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tftp_log(LOG_DEBUG, "Sending WRQ: filename: '%s', mode '%s'",
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filename, mode
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);
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DROPPACKETn("send_wrq", 0);
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tp = (struct tftphdr *)buf;
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tp->th_opcode = htons((u_short)WRQ);
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size = offsetof(struct tftphdr, th_stuff);
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bp = tp->th_stuff;
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strlcpy(bp, filename, sizeof(buf) - size);
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bp += strlen(filename);
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*bp = 0;
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bp++;
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size += strlen(filename) + 1;
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strlcpy(bp, mode, sizeof(buf) - size);
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bp += strlen(mode);
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*bp = 0;
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bp++;
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size += strlen(mode) + 1;
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if (options_rfc_enabled)
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size += make_options(peer, bp, sizeof(buf) - size);
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n = sendto(peer, buf, size, 0,
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(struct sockaddr *)&peer_sock, peer_sock.ss_len);
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if (n != size) {
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tftp_log(LOG_ERR, "send_wrq: %s", strerror(errno));
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return (1);
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}
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return (0);
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}
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/*
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* Send an RRQ packet (write request).
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*/
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int
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send_rrq(int peer, char *filename, char *mode)
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{
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int n;
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struct tftphdr *tp;
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char *bp;
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char buf[MAXPKTSIZE];
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int size;
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if (debug & DEBUG_PACKETS)
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tftp_log(LOG_DEBUG, "Sending RRQ: filename: '%s', mode '%s'",
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filename, mode
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);
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DROPPACKETn("send_rrq", 0);
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tp = (struct tftphdr *)buf;
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tp->th_opcode = htons((u_short)RRQ);
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size = offsetof(struct tftphdr, th_stuff);
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bp = tp->th_stuff;
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strlcpy(bp, filename, sizeof(buf) - size);
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bp += strlen(filename);
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*bp = 0;
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bp++;
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size += strlen(filename) + 1;
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strlcpy(bp, mode, sizeof(buf) - size);
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bp += strlen(mode);
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*bp = 0;
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bp++;
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size += strlen(mode) + 1;
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if (options_rfc_enabled) {
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options_set_request(OPT_TSIZE, "0");
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size += make_options(peer, bp, sizeof(buf) - size);
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}
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n = sendto(peer, buf, size, 0,
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(struct sockaddr *)&peer_sock, peer_sock.ss_len);
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if (n != size) {
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tftp_log(LOG_ERR, "send_rrq: %d %s", n, strerror(errno));
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return (1);
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}
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return (0);
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}
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/*
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* Send an OACK packet (option acknowledgement).
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*/
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int
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send_oack(int peer)
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{
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struct tftphdr *tp;
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int size, i, n;
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char *bp;
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char buf[MAXPKTSIZE];
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if (debug & DEBUG_PACKETS)
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tftp_log(LOG_DEBUG, "Sending OACK");
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DROPPACKETn("send_oack", 0);
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/*
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* Send back an options acknowledgement (only the ones with
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* a reply for)
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*/
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tp = (struct tftphdr *)buf;
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bp = buf + 2;
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size = sizeof(buf) - 2;
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tp->th_opcode = htons((u_short)OACK);
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for (i = 0; options[i].o_type != NULL; i++) {
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if (options[i].o_reply != NULL) {
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n = snprintf(bp, size, "%s%c%s", options[i].o_type,
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0, options[i].o_reply);
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bp += n+1;
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size -= n+1;
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if (size < 0) {
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tftp_log(LOG_ERR, "oack: buffer overflow");
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exit(1);
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}
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}
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}
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size = bp - buf;
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if (sendto(peer, buf, size, 0,
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(struct sockaddr *)&peer_sock, peer_sock.ss_len) != size) {
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tftp_log(LOG_INFO, "send_oack: %s", strerror(errno));
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return (1);
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}
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return (0);
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}
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/*
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* Send an ACK packet (acknowledgement).
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*/
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int
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send_ack(int fp, uint16_t block)
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{
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struct tftphdr *tp;
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int size;
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char buf[MAXPKTSIZE];
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if (debug & DEBUG_PACKETS)
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tftp_log(LOG_DEBUG, "Sending ACK for block %d", block);
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DROPPACKETn("send_ack", 0);
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tp = (struct tftphdr *)buf;
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size = sizeof(buf) - 2;
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tp->th_opcode = htons((u_short)ACK);
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tp->th_block = htons((u_short)block);
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size = 4;
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if (sendto(fp, buf, size, 0,
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(struct sockaddr *)&peer_sock, peer_sock.ss_len) != size) {
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tftp_log(LOG_INFO, "send_ack: %s", strerror(errno));
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return (1);
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}
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return (0);
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}
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/*
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* Send a DATA packet
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*/
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int
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send_data(int peer, uint16_t block, char *data, int size)
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{
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char buf[MAXPKTSIZE];
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struct tftphdr *pkt;
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int n;
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if (debug & DEBUG_PACKETS)
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tftp_log(LOG_DEBUG, "Sending DATA packet %d of %d bytes",
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block, size);
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DROPPACKETn("send_data", 0);
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pkt = (struct tftphdr *)buf;
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pkt->th_opcode = htons((u_short)DATA);
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pkt->th_block = htons((u_short)block);
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memcpy(pkt->th_data, data, size);
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n = send_packet(peer, block, (char *)pkt, size + 4);
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return (n);
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}
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/*
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* Receive a packet
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*/
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static jmp_buf timeoutbuf;
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static void
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timeout(int sig __unused)
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{
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/* tftp_log(LOG_DEBUG, "Timeout\n"); Inside a signal handler... */
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longjmp(timeoutbuf, 1);
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}
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int
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receive_packet(int peer, char *data, int size, struct sockaddr_storage *from,
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int thistimeout)
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{
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struct tftphdr *pkt;
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struct sockaddr_storage from_local;
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struct sockaddr_storage *pfrom;
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socklen_t fromlen;
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int n;
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static int timed_out;
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if (debug & DEBUG_PACKETS)
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tftp_log(LOG_DEBUG,
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"Waiting %d seconds for packet", timeoutpacket);
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pkt = (struct tftphdr *)data;
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signal(SIGALRM, timeout);
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timed_out = setjmp(timeoutbuf);
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alarm(thistimeout);
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if (timed_out != 0) {
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tftp_log(LOG_ERR, "receive_packet: timeout");
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alarm(0);
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return (RP_TIMEOUT);
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}
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pfrom = (from == NULL) ? &from_local : from;
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fromlen = sizeof(*pfrom);
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n = recvfrom(peer, data, size, 0, (struct sockaddr *)pfrom, &fromlen);
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alarm(0);
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DROPPACKETn("receive_packet", RP_TIMEOUT);
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if (n < 0) {
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tftp_log(LOG_ERR, "receive_packet: timeout");
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return (RP_TIMEOUT);
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}
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if (n < 0) {
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/* No idea what could have happened if it isn't a timeout */
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tftp_log(LOG_ERR, "receive_packet: %s", strerror(errno));
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return (RP_RECVFROM);
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}
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if (n < 4) {
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tftp_log(LOG_ERR,
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"receive_packet: packet too small (%d bytes)", n);
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return (RP_TOOSMALL);
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}
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pkt->th_opcode = ntohs((u_short)pkt->th_opcode);
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if (pkt->th_opcode == DATA ||
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pkt->th_opcode == ACK)
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pkt->th_block = ntohs((u_short)pkt->th_block);
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if (pkt->th_opcode == DATA && n > pktsize) {
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tftp_log(LOG_ERR, "receive_packet: packet too big");
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return (RP_TOOBIG);
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}
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if (((struct sockaddr_in *)(pfrom))->sin_addr.s_addr !=
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((struct sockaddr_in *)(&peer_sock))->sin_addr.s_addr) {
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tftp_log(LOG_ERR,
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"receive_packet: received packet from wrong source");
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return (RP_WRONGSOURCE);
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}
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if (pkt->th_opcode == ERROR) {
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tftp_log(pkt->th_code == EUNDEF ? LOG_DEBUG : LOG_ERR,
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"Got ERROR packet: %s", pkt->th_msg);
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return (RP_ERROR);
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}
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if (debug & DEBUG_PACKETS)
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tftp_log(LOG_DEBUG, "Received %d bytes in a %s packet",
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n, packettype(pkt->th_opcode));
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return n - 4;
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}
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