[unix-history] / usr / src / usr.bin / tn3270 / api / api_exch.c

#include <stdio.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()
{
    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 i;
    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;
    }
    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;
	}
    }
    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;
char
    *location;
{
    int netleng = htons(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 i, netleng = htons(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 %d.\n",
		type, length, ntohs(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;
    strcpy(whoarewe, ourname);		/* For error messages */

    my_sequence = your_sequence = 0;

    conversation = CONTENTION;		/* We don't know which direction */

    IBUFRESET();
    OBUFRESET();

    return 0;
}
Commit	Line	Data
ba212048 GM	1	#include <stdio.h>
	2
	3	#include "api_exch.h"
	4
62946391 GM	5	static int sock; /* Socket number */
62946391 GM	6
224a681b	7	static char whoarewe[40] = "";
d024bcc4 GM	8	#define WHO_ARE_WE() fprintf(stderr, "(API %s) ", whoarewe);
	9
	10	static enum {CONTENTION, SEND, RECEIVE } conversation;
	11
	12	static struct exch_exch exch_state;
	13
	14	static unsigned int
	15	my_sequence,
	16	your_sequence;
224a681b	17
8d951982	18	static char ibuffer[4000], ibuf_next, ibuf_last;
ba212048	19	#define IBUFADDED(i) ibuf_last += (i)
8d951982	20	#define IBUFAVAILABLE() (ibuf_last-ibuf_next)
ba212048	21	#define IBUFFER() ibuffer
8d951982	22	#define IBUFFREE() (ibuffer+sizeof ibuffer-ibuf_last-1)
d024bcc4	23	#define IBUFGETBYTES(w,l) { memcpy(w, ibuf_next, l); ibuf_next += l; }
ba212048 GM	24	#define IBUFRESET() (ibuf_next = ibuf_last = ibuffer)
ba212048 GM	25
8d951982	26	char obuffer[4000], *obuf_next;
ba212048	27	#define OBUFADDBYTES(w,l) { memcpy(obuf_next, w, l); obuf_next += l; }
ba212048 GM	28	#define OBUFAVAILABLE() (obuf_next - obuffer)
	29	#define OBUFFER() obuffer
	30	#define OBUFRESET() obuf_next = obuffer
	31	#define OBUFROOM() (obuffer+sizeof obuffer-obuf_next)
	32
	33
	34	static int
	35	outflush()
	36	{
	37	int length = OBUFAVAILABLE();
	38
	39	if (length != 0) {
	40	if (write(sock, OBUFFER(), length) != length) {
d024bcc4	41	WHO_ARE_WE();
224a681b	42	perror("write");
ba212048 GM	43	return -1;
	44	}
	45	OBUFRESET();
	46	}
	47	return 0; /* All OK */
	48	}
	49
	50
	51	static int
8d951982 GM	52	iget(location, length)
	53	char *location;
	54	int length;
ba212048 GM	55	{
ba212048 GM	56	int i;
8d951982	57	int count;
ba212048 GM	58
	59	if (OBUFAVAILABLE()) {
	60	if (outflush() == -1) {
	61	return -1;
	62	}
	63	}
8d951982 GM	64	if ((count = IBUFAVAILABLE()) != 0) {
	65	if (count > length) {
	66	count = length;
	67	}
	68	IBUFGETBYTES(location, count);
	69	length -= count;
	70	location += count;
d024bcc4	71	}
8d951982 GM	72	while (length) {
	73	if (ibuf_next == ibuf_last) {
	74	IBUFRESET();
	75	}
	76	if ((count = read(sock, IBUFFER(), IBUFFREE())) < 0) {
d024bcc4	77	WHO_ARE_WE();
224a681b GM	78	perror("read");
	79	return -1;
	80	}
8d951982	81	if (count == 0) {
224a681b	82	/* Reading past end-of-file */
d024bcc4 GM	83	WHO_ARE_WE();
d024bcc4 GM	84	fprintf(stderr, "End of file read\r\n");
ba212048 GM	85	return -1;
ba212048 GM	86	}
8d951982 GM	87	IBUFADDED(count);
	88	if (count > length) {
	89	count = length;
	90	}
	91	IBUFGETBYTES(location, count);
	92	length -= count;
	93	location += count;
ba212048 GM	94	}
	95	return 0;
	96	}
	97
d024bcc4 GM	98	static char *
	99	exch_to_ascii(exch)
	100	int exch; /* opcode to decode */
	101	{
	102	switch (exch) {
	103	case EXCH_EXCH_COMMAND:
	104	return "Command";
	105	case EXCH_EXCH_TYPE:
	106	return "Type";
	107	case EXCH_EXCH_TURNAROUND:
	108	return "Turnaround";
	109	case EXCH_EXCH_RTS:
	110	return "Request to Send";
	111	default:
	112	{
	113	static char unknown[40];
	114
	115	sprintf(unknown, "(Unknown exchange 0x%02x)", exch&0xff);
	116	return unknown;
	117	}
	118	}
	119	}
	120
	121	/*
	122	* Send the exch structure, updating the sequnce number field.
	123	*/
	124
	125	static int
	126	send_state()
	127	{
	128	if (OBUFROOM() < sizeof exch_state) {
	129	if (outflush() == -1) {
	130	return -1;
	131	}
	132	}
e1e082cf GM	133	my_sequence = (my_sequence+1)&0xff;
e1e082cf GM	134	exch_state.my_sequence = my_sequence;
d024bcc4 GM	135	exch_state.your_sequence = your_sequence;
	136	OBUFADDBYTES((char *)&exch_state, sizeof exch_state);
	137	return 0;
	138	}
	139
	140	/*
	141	* Receive the exch structure from the other side, checking
	142	* sequence numbering.
	143	*/
	144
	145	static int
	146	receive_state()
	147	{
8d951982 GM	148	if (iget((char *)&exch_state, sizeof exch_state) == -1) {
8d951982 GM	149	return -1;
d024bcc4	150	}
d024bcc4 GM	151	if (conversation != CONTENTION) {
	152	if (exch_state.your_sequence != my_sequence) {
	153	WHO_ARE_WE();
	154	fprintf(stderr, "Send sequence number mismatch.\n");
	155	return -1;
	156	}
e1e082cf	157	if (exch_state.my_sequence != ((++your_sequence)&0xff)) {
d024bcc4 GM	158	WHO_ARE_WE();
	159	fprintf(stderr, "Receive sequence number mismatch.\n");
	160	return -1;
	161	}
d024bcc4	162	}
e1e082cf	163	your_sequence = exch_state.my_sequence;
d024bcc4 GM	164	return 0;
	165	}
	166
	167	static int
	168	enter_receive()
	169	{
	170	switch (conversation) {
	171	case CONTENTION:
	172	exch_state.opcode = EXCH_EXCH_TURNAROUND;
	173	if (send_state() == -1) {
	174	return -1;
	175	}
	176	if (receive_state() == -1) {
	177	return -1;
	178	}
	179	if (exch_state.opcode != EXCH_EXCH_RTS) {
	180	WHO_ARE_WE();
	181	fprintf(stderr, "In CONTENTION state: ");
	182	if (exch_state.opcode == EXCH_EXCH_TURNAROUND) {
	183	fprintf(stderr,
	184	"Both sides tried to enter RECEIVE state.\n");
	185	} else {
	186	fprintf(stderr,
	187	"Protocol error trying to enter RECEIVE state.\n");
	188	}
	189	return -1;
	190	}
	191	break;
	192	case SEND:
	193	exch_state.opcode = EXCH_EXCH_TURNAROUND;
	194	if (send_state() == -1) {
	195	return -1;
	196	}
	197	break;
	198	}
	199	conversation = RECEIVE;
	200	return 0;
	201	}
	202
	203	static int
	204	enter_send()
	205	{
	206	switch (conversation) {
	207	case CONTENTION:
	208	exch_state.opcode = EXCH_EXCH_RTS;
	209	if (send_state() == -1) {
	210	return -1;
	211	}
	212	/* fall through */
	213	case RECEIVE:
	214	if (receive_state() == -1) {
	215	return -1;
	216	}
	217	if (exch_state.opcode != EXCH_EXCH_TURNAROUND) {
	218	WHO_ARE_WE();
	219	fprintf(stderr, "Conversation error - both sides in SEND state.\n");
	220	return -1;
	221	}
	222	}
	223	conversation = SEND;
	224	return 0;
	225	}
	226
62946391	227	int
d024bcc4	228	api_exch_nextcommand()
62946391	229	{
d024bcc4 GM	230	if (conversation != RECEIVE) {
d024bcc4 GM	231	if (enter_receive() == -1) {
62946391 GM	232	return -1;
	233	}
	234	}
d024bcc4 GM	235	if (receive_state() == -1) {
	236	return -1;
	237	}
	238	if (exch_state.opcode != EXCH_EXCH_COMMAND) {
	239	WHO_ARE_WE();
	240	fprintf(stderr, "Expected a %s exchange, received a %s exchange.\n",
	241	exch_to_ascii(EXCH_EXCH_COMMAND), exch_to_ascii(exch_state.opcode));
	242	return -1;
	243	}
	244	return exch_state.command_or_type;
62946391 GM	245	}
	246
	247
	248	int
ba212048 GM	249	api_exch_incommand(command)
	250	int command;
	251	{
	252	int i;
	253
d024bcc4 GM	254	if ((i = api_exch_nextcommand()) == -1) {
d024bcc4 GM	255	return -1;
ba212048	256	}
ba212048	257	if (i != command) {
d024bcc4	258	WHO_ARE_WE();
ba212048 GM	259	fprintf(stderr, "Expected API command 0x%x, got API command 0x%x.\n",
	260	command, i);
	261	return -1;
	262	}
	263	return 0;
	264	}
	265
	266
62946391	267	int
ba212048 GM	268	api_exch_outcommand(command)
	269	int command;
	270	{
d024bcc4 GM	271	if (conversation != SEND) {
d024bcc4 GM	272	if (enter_send() == -1) {
ba212048 GM	273	return -1;
	274	}
	275	}
d024bcc4 GM	276	exch_state.command_or_type = command;
	277	exch_state.opcode = EXCH_EXCH_COMMAND;
	278	if (send_state() == -1) {
	279	return -1;
	280	} else {
	281	return 0;
	282	}
ba212048 GM	283	}
	284
	285
62946391	286	int
ba212048 GM	287	api_exch_outtype(type, length, location)
	288	int
	289	type,
	290	length;
	291	char
	292	*location;
	293	{
	294	int netleng = htons(length);
	295
d024bcc4 GM	296	if (conversation != SEND) {
d024bcc4 GM	297	if (enter_send() == -1) {
ba212048 GM	298	return -1;
	299	}
	300	}
d024bcc4 GM	301	exch_state.opcode = EXCH_EXCH_TYPE;
	302	exch_state.command_or_type = type;
	303	exch_state.length = netleng;
	304	if (send_state() == -1) {
	305	return -1;
	306	}
	307	if (length) {
	308	if (OBUFROOM() > length) {
	309	OBUFADDBYTES(location, length);
	310	} else {
	311	if (outflush() == -1) {
	312	return -1;
	313	}
	314	if (write(sock, location, length) != length) {
	315	WHO_ARE_WE();
	316	perror("write");
	317	return -1;
	318	}
ba212048 GM	319	}
ba212048 GM	320	}
d024bcc4	321	return 0;
ba212048 GM	322	}
	323
	324
62946391	325	int
ba212048 GM	326	api_exch_intype(type, length, location)
	327	int
	328	type,
	329	length;
	330	char
	331	*location;
	332	{
	333	int i, netleng = htons(length);
	334
d024bcc4 GM	335	if (conversation != RECEIVE) {
d024bcc4 GM	336	if (enter_receive() == -1) {
ba212048 GM	337	return -1;
	338	}
	339	}
d024bcc4 GM	340	if (receive_state() == -1) {
	341	return -1;
	342	}
	343	if (exch_state.opcode != EXCH_EXCH_TYPE) {
	344	WHO_ARE_WE();
	345	fprintf(stderr,
	346	"Expected to receive a %s exchange, received a %s exchange.\n",
	347	exch_to_ascii(EXCH_EXCH_TYPE), exch_to_ascii(exch_state.opcode));
ba212048 GM	348	return -1;
ba212048 GM	349	}
d024bcc4 GM	350	if (exch_state.command_or_type != type) {
	351	WHO_ARE_WE();
	352	fprintf(stderr, "Expected type 0x%x, got type 0x%x.\n",
	353	type, exch_state.command_or_type);
	354	return -1;
	355	}
	356	if (exch_state.length != netleng) {
ba212048	357	fprintf(stderr, "Type 0x%x - expected length %d, received length %d.\n",
d024bcc4	358	type, length, ntohs(exch_state.length));
ba212048 GM	359	return -1;
ba212048 GM	360	}
8d951982 GM	361	if (iget(location, length) == -1) {
8d951982 GM	362	return -1;
ba212048 GM	363	}
	364	return 0;
	365	}
62946391	366
d024bcc4 GM	367	int
	368	api_exch_flush()
	369	{
	370	return outflush();
	371	}
	372
62946391	373	int
224a681b	374	api_exch_init(sock_number, ourname)
62946391	375	int sock_number;
224a681b	376	char *ourname;
62946391 GM	377	{
62946391 GM	378	sock = sock_number;
224a681b	379	strcpy(whoarewe, ourname); /* For error messages */
62946391	380
d024bcc4 GM	381	my_sequence = your_sequence = 0;
	382
	383	conversation = CONTENTION; /* We don't know which direction */
	384
62946391 GM	385	IBUFRESET();
	386	OBUFRESET();
	387
	388	return 0;
	389	}