NetBSD-5.0.2/usr.bin/tn3270/api/api_exch.c
/* $NetBSD: api_exch.c,v 1.8 2003/08/07 11:16:24 agc Exp $ */
/*-
* Copyright (c) 1988 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
#if defined(__RCSID) && !defined(lint)
#if 0
static char sccsid[] = "@(#)api_exch.c 4.2 (Berkeley) 4/26/91";
#else
__RCSID("$NetBSD: api_exch.c,v 1.8 2003/08/07 11:16:24 agc Exp $");
#endif
#endif /* not lint */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "../general/general.h"
#include "api_exch.h"
static int sock; /* Socket number */
static char whoarewe[40] = "";
#define WHO_ARE_WE() fprintf(stderr, "(API %s) ", whoarewe);
static enum {CONTENTION, SEND, RECEIVE } conversation;
static struct exch_exch exch_state;
static unsigned int
my_sequence,
your_sequence;
static char ibuffer[4000], *ibuf_next, *ibuf_last;
#define IBUFADDED(i) ibuf_last += (i)
#define IBUFAVAILABLE() (ibuf_last-ibuf_next)
#define IBUFFER() ibuffer
#define IBUFFREE() (ibuffer+sizeof ibuffer-ibuf_last-1)
#define IBUFGETBYTES(w,l) { memcpy(w, ibuf_next, l); ibuf_next += l; }
#define IBUFRESET() (ibuf_next = ibuf_last = ibuffer)
char obuffer[4000], *obuf_next;
#define OBUFADDBYTES(w,l) { memcpy(obuf_next, w, l); obuf_next += l; }
#define OBUFAVAILABLE() (obuf_next - obuffer)
#define OBUFFER() obuffer
#define OBUFRESET() obuf_next = obuffer
#define OBUFROOM() (obuffer+sizeof obuffer-obuf_next)
static int outflush(void);
static int iget(char *, int);
static char *exch_to_ascii(int);
static int send_state(void);
static int receive_state(void);
static int enter_receive(void);
static int enter_send(void);
static int
outflush()
{
int length = OBUFAVAILABLE();
if (length != 0) {
if (write(sock, OBUFFER(), length) != length) {
WHO_ARE_WE();
perror("write");
return -1;
}
OBUFRESET();
}
return 0; /* All OK */
}
static int
iget(location, length)
char *location;
int length;
{
int count;
if (OBUFAVAILABLE()) {
if (outflush() == -1) {
return -1;
}
}
if ((count = IBUFAVAILABLE()) != 0) {
if (count > length) {
count = length;
}
IBUFGETBYTES(location, count);
length -= count;
location += count;
}
while (length) {
if (ibuf_next == ibuf_last) {
IBUFRESET();
}
if ((count = read(sock, IBUFFER(), IBUFFREE())) < 0) {
WHO_ARE_WE();
perror("read");
return -1;
}
if (count == 0) {
/* Reading past end-of-file */
WHO_ARE_WE();
fprintf(stderr, "End of file read\r\n");
return -1;
}
IBUFADDED(count);
if (count > length) {
count = length;
}
IBUFGETBYTES(location, count);
length -= count;
location += count;
}
return 0;
}
static char *
exch_to_ascii(exch)
int exch; /* opcode to decode */
{
switch (exch) {
case EXCH_EXCH_COMMAND:
return "Command";
case EXCH_EXCH_TYPE:
return "Type";
case EXCH_EXCH_TURNAROUND:
return "Turnaround";
case EXCH_EXCH_RTS:
return "Request to Send";
default:
{
static char unknown[40];
sprintf(unknown, "(Unknown exchange 0x%02x)", exch&0xff);
return unknown;
}
}
}
/*
* Send the exch structure, updating the sequnce number field.
*/
static int
send_state()
{
if (OBUFROOM() < sizeof exch_state) {
if (outflush() == -1) {
return -1;
}
}
my_sequence = (my_sequence+1)&0xff;
exch_state.my_sequence = my_sequence;
exch_state.your_sequence = your_sequence;
OBUFADDBYTES((char *)&exch_state, sizeof exch_state);
return 0;
}
/*
* Receive the exch structure from the other side, checking
* sequence numbering.
*/
static int
receive_state()
{
if (iget((char *)&exch_state, sizeof exch_state) == -1) {
return -1;
}
if (conversation != CONTENTION) {
if (exch_state.your_sequence != my_sequence) {
WHO_ARE_WE();
fprintf(stderr, "Send sequence number mismatch.\n");
return -1;
}
if (exch_state.my_sequence != ((++your_sequence)&0xff)) {
WHO_ARE_WE();
fprintf(stderr, "Receive sequence number mismatch.\n");
return -1;
}
}
your_sequence = exch_state.my_sequence;
return 0;
}
static int
enter_receive()
{
switch (conversation) {
case CONTENTION:
exch_state.opcode = EXCH_EXCH_TURNAROUND;
if (send_state() == -1) {
return -1;
}
if (receive_state() == -1) {
return -1;
}
if (exch_state.opcode != EXCH_EXCH_RTS) {
WHO_ARE_WE();
fprintf(stderr, "In CONTENTION state: ");
if (exch_state.opcode == EXCH_EXCH_TURNAROUND) {
fprintf(stderr,
"Both sides tried to enter RECEIVE state.\n");
} else {
fprintf(stderr,
"Protocol error trying to enter RECEIVE state.\n");
}
return -1;
}
break;
case SEND:
exch_state.opcode = EXCH_EXCH_TURNAROUND;
if (send_state() == -1) {
return -1;
}
break;
case RECEIVE:
abort(); /* Unhandled case; remove abort if we die here */
}
conversation = RECEIVE;
return 0;
}
static int
enter_send()
{
switch (conversation) {
case CONTENTION:
exch_state.opcode = EXCH_EXCH_RTS;
if (send_state() == -1) {
return -1;
}
/* fall through */
case RECEIVE:
if (receive_state() == -1) {
return -1;
}
if (exch_state.opcode != EXCH_EXCH_TURNAROUND) {
WHO_ARE_WE();
fprintf(stderr, "Conversation error - both sides in SEND state.\n");
return -1;
}
case SEND:
abort(); /* Unhandled case; remove abort if we die here */
}
conversation = SEND;
return 0;
}
int
api_exch_nextcommand()
{
if (conversation != RECEIVE) {
if (enter_receive() == -1) {
return -1;
}
}
if (receive_state() == -1) {
return -1;
}
if (exch_state.opcode != EXCH_EXCH_COMMAND) {
WHO_ARE_WE();
fprintf(stderr, "Expected a %s exchange, received a %s exchange.\n",
exch_to_ascii(EXCH_EXCH_COMMAND), exch_to_ascii(exch_state.opcode));
return -1;
}
return exch_state.command_or_type;
}
int
api_exch_incommand(command)
int command;
{
int i;
if ((i = api_exch_nextcommand()) == -1) {
return -1;
}
if (i != command) {
WHO_ARE_WE();
fprintf(stderr, "Expected API command 0x%x, got API command 0x%x.\n",
command, i);
return -1;
}
return 0;
}
int
api_exch_outcommand(command)
int command;
{
if (conversation != SEND) {
if (enter_send() == -1) {
return -1;
}
}
exch_state.command_or_type = command;
exch_state.opcode = EXCH_EXCH_COMMAND;
if (send_state() == -1) {
return -1;
} else {
return 0;
}
}
int
api_exch_outtype(type, length, location)
int
type,
length;
const char
*location;
{
int netleng = length;
if (conversation != SEND) {
if (enter_send() == -1) {
return -1;
}
}
exch_state.opcode = EXCH_EXCH_TYPE;
exch_state.command_or_type = type;
exch_state.length = netleng;
if (send_state() == -1) {
return -1;
}
if (length) {
if (OBUFROOM() > length) {
OBUFADDBYTES(location, length);
} else {
if (outflush() == -1) {
return -1;
}
if (write(sock, location, length) != length) {
WHO_ARE_WE();
perror("write");
return -1;
}
}
}
return 0;
}
int
api_exch_intype(type, length, location)
int
type,
length;
char
*location;
{
int netleng = length;
if (conversation != RECEIVE) {
if (enter_receive() == -1) {
return -1;
}
}
if (receive_state() == -1) {
return -1;
}
if (exch_state.opcode != EXCH_EXCH_TYPE) {
WHO_ARE_WE();
fprintf(stderr,
"Expected to receive a %s exchange, received a %s exchange.\n",
exch_to_ascii(EXCH_EXCH_TYPE), exch_to_ascii(exch_state.opcode));
return -1;
}
if (exch_state.command_or_type != type) {
WHO_ARE_WE();
fprintf(stderr, "Expected type 0x%x, got type 0x%x.\n",
type, exch_state.command_or_type);
return -1;
}
if (exch_state.length != netleng) {
fprintf(stderr, "Type 0x%x - expected length %d, received length %u.\n",
type, length, exch_state.length);
return -1;
}
if (iget(location, length) == -1) {
return -1;
}
return 0;
}
int
api_exch_flush()
{
return outflush();
}
int
api_exch_init(sock_number, ourname)
int sock_number;
char *ourname;
{
sock = sock_number;
(void) strcpy(whoarewe, ourname); /* For error messages */
my_sequence = your_sequence = 0;
conversation = CONTENTION; /* We don't know which direction */
IBUFRESET();
OBUFRESET();
return 0;
}