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Annotation of 43BSDTahoe/ucb/tn3270/api/api_exch.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1988 Regents of the University of California.
        !             3:  * All rights reserved.
        !             4:  *
        !             5:  * Redistribution and use in source and binary forms are permitted
        !             6:  * provided that this notice is preserved and that due credit is given
        !             7:  * to the University of California at Berkeley. The name of the University
        !             8:  * may not be used to endorse or promote products derived from this
        !             9:  * software without specific prior written permission. This software
        !            10:  * is provided ``as is'' without express or implied warranty.
        !            11:  */
        !            12: 
        !            13: #ifndef lint
        !            14: static char sccsid[] = "@(#)api_exch.c 3.2 (Berkeley) 3/28/88";
        !            15: #endif /* not lint */
        !            16: 
        !            17: #include <stdio.h>
        !            18: 
        !            19: #include "../general/general.h"
        !            20: 
        !            21: #include "api_exch.h"
        !            22: 
        !            23: static int sock;               /* Socket number */
        !            24: 
        !            25: static char whoarewe[40] = "";
        !            26: #define        WHO_ARE_WE()    fprintf(stderr, "(API %s) ", whoarewe);
        !            27: 
        !            28: static enum {CONTENTION, SEND, RECEIVE } conversation;
        !            29: 
        !            30: static struct exch_exch exch_state;
        !            31: 
        !            32: static unsigned int
        !            33:     my_sequence,
        !            34:     your_sequence;
        !            35: 
        !            36: static char ibuffer[4000], *ibuf_next, *ibuf_last;
        !            37: #define        IBUFADDED(i)            ibuf_last += (i)
        !            38: #define        IBUFAVAILABLE()         (ibuf_last-ibuf_next)
        !            39: #define        IBUFFER()               ibuffer
        !            40: #define        IBUFFREE()              (ibuffer+sizeof ibuffer-ibuf_last-1)
        !            41: #define        IBUFGETBYTES(w,l)       { memcpy(w, ibuf_next, l); ibuf_next += l; }
        !            42: #define        IBUFRESET()             (ibuf_next = ibuf_last = ibuffer)
        !            43: 
        !            44: char obuffer[4000], *obuf_next;
        !            45: #define        OBUFADDBYTES(w,l)       { memcpy(obuf_next, w, l); obuf_next += l; }
        !            46: #define        OBUFAVAILABLE()         (obuf_next - obuffer)
        !            47: #define        OBUFFER()               obuffer
        !            48: #define        OBUFRESET()             obuf_next = obuffer
        !            49: #define        OBUFROOM()              (obuffer+sizeof obuffer-obuf_next)
        !            50: 
        !            51: 
        !            52: static int
        !            53: outflush()
        !            54: {
        !            55:     int length = OBUFAVAILABLE();
        !            56: 
        !            57:     if (length != 0) {
        !            58:        if (write(sock, OBUFFER(), length) != length) {
        !            59:            WHO_ARE_WE();
        !            60:            perror("write");
        !            61:            return -1;
        !            62:        }
        !            63:        OBUFRESET();
        !            64:     }
        !            65:     return 0;                          /* All OK */
        !            66: }
        !            67: 
        !            68: 
        !            69: static int
        !            70: iget(location, length)
        !            71: char   *location;
        !            72: int    length;
        !            73: {
        !            74:     int i;
        !            75:     int count;
        !            76: 
        !            77:     if (OBUFAVAILABLE()) {
        !            78:        if (outflush() == -1) {
        !            79:            return -1;
        !            80:        }
        !            81:     }
        !            82:     if ((count = IBUFAVAILABLE()) != 0) {
        !            83:        if (count > length) {
        !            84:            count = length;
        !            85:        }
        !            86:        IBUFGETBYTES(location, count);
        !            87:        length -= count;
        !            88:        location += count;
        !            89:     }
        !            90:     while (length) {
        !            91:        if (ibuf_next == ibuf_last) {
        !            92:            IBUFRESET();
        !            93:        }
        !            94:        if ((count = read(sock, IBUFFER(), IBUFFREE())) < 0) {
        !            95:            WHO_ARE_WE();
        !            96:            perror("read");
        !            97:            return -1;
        !            98:        }
        !            99:        if (count == 0) {
        !           100:            /* Reading past end-of-file */
        !           101:            WHO_ARE_WE();
        !           102:            fprintf(stderr, "End of file read\r\n");
        !           103:            return -1;
        !           104:        }
        !           105:        IBUFADDED(count);
        !           106:        if (count > length) {
        !           107:            count = length;
        !           108:        }
        !           109:        IBUFGETBYTES(location, count);
        !           110:        length -= count;
        !           111:        location += count;
        !           112:     }
        !           113:     return 0;
        !           114: }
        !           115: 
        !           116: static char *
        !           117: exch_to_ascii(exch)
        !           118: int exch;                      /* opcode to decode */
        !           119: {
        !           120:     switch (exch) {
        !           121:     case EXCH_EXCH_COMMAND:
        !           122:        return "Command";
        !           123:     case EXCH_EXCH_TYPE:
        !           124:        return "Type";
        !           125:     case EXCH_EXCH_TURNAROUND:
        !           126:        return "Turnaround";
        !           127:     case EXCH_EXCH_RTS:
        !           128:        return "Request to Send";
        !           129:     default:
        !           130:        {
        !           131:            static char unknown[40];
        !           132: 
        !           133:            sprintf(unknown, "(Unknown exchange 0x%02x)", exch&0xff);
        !           134:            return unknown;
        !           135:        }
        !           136:     }
        !           137: }
        !           138: 
        !           139: /*
        !           140:  * Send the exch structure, updating the sequnce number field.
        !           141:  */
        !           142: 
        !           143: static int
        !           144: send_state()
        !           145: {
        !           146:     if (OBUFROOM() < sizeof exch_state) {
        !           147:        if (outflush() == -1) {
        !           148:            return -1;
        !           149:        }
        !           150:     }
        !           151:     my_sequence = (my_sequence+1)&0xff;
        !           152:     exch_state.my_sequence = my_sequence;
        !           153:     exch_state.your_sequence = your_sequence;
        !           154:     OBUFADDBYTES((char *)&exch_state, sizeof exch_state);
        !           155:     return 0;
        !           156: }
        !           157: 
        !           158: /*
        !           159:  * Receive the exch structure from the other side, checking
        !           160:  * sequence numbering.
        !           161:  */
        !           162: 
        !           163: static int
        !           164: receive_state()
        !           165: {
        !           166:     if (iget((char *)&exch_state, sizeof exch_state) == -1) {
        !           167:        return -1;
        !           168:     }
        !           169:     if (conversation != CONTENTION) {
        !           170:        if (exch_state.your_sequence != my_sequence) {
        !           171:            WHO_ARE_WE();
        !           172:            fprintf(stderr, "Send sequence number mismatch.\n");
        !           173:            return -1;
        !           174:        }
        !           175:        if (exch_state.my_sequence != ((++your_sequence)&0xff)) {
        !           176:            WHO_ARE_WE();
        !           177:            fprintf(stderr, "Receive sequence number mismatch.\n");
        !           178:            return -1;
        !           179:        }
        !           180:     }
        !           181:     your_sequence = exch_state.my_sequence;
        !           182:     return 0;
        !           183: }
        !           184: 
        !           185: static int
        !           186: enter_receive()
        !           187: {
        !           188:     switch (conversation) {
        !           189:     case CONTENTION:
        !           190:        exch_state.opcode = EXCH_EXCH_TURNAROUND;
        !           191:        if (send_state() == -1) {
        !           192:            return -1;
        !           193:        }
        !           194:        if (receive_state() == -1) {
        !           195:            return -1;
        !           196:        }
        !           197:        if (exch_state.opcode != EXCH_EXCH_RTS) {
        !           198:            WHO_ARE_WE();
        !           199:            fprintf(stderr, "In CONTENTION state:  ");
        !           200:            if (exch_state.opcode == EXCH_EXCH_TURNAROUND) {
        !           201:                fprintf(stderr,
        !           202:                    "Both sides tried to enter RECEIVE state.\n");
        !           203:            } else {
        !           204:                fprintf(stderr,
        !           205:                    "Protocol error trying to enter RECEIVE state.\n");
        !           206:            }
        !           207:            return -1;
        !           208:        }
        !           209:        break;
        !           210:     case SEND:
        !           211:        exch_state.opcode = EXCH_EXCH_TURNAROUND;
        !           212:        if (send_state() == -1) {
        !           213:            return -1;
        !           214:        }
        !           215:        break;
        !           216:     }
        !           217:     conversation = RECEIVE;
        !           218:     return 0;
        !           219: }
        !           220: 
        !           221: static int
        !           222: enter_send()
        !           223: {
        !           224:     switch (conversation) {
        !           225:     case CONTENTION:
        !           226:        exch_state.opcode = EXCH_EXCH_RTS;
        !           227:        if (send_state() == -1) {
        !           228:            return -1;
        !           229:        }
        !           230:         /* fall through */
        !           231:     case RECEIVE:
        !           232:        if (receive_state() == -1) {
        !           233:            return -1;
        !           234:        }
        !           235:        if (exch_state.opcode != EXCH_EXCH_TURNAROUND) {
        !           236:            WHO_ARE_WE();
        !           237:            fprintf(stderr, "Conversation error - both sides in SEND state.\n");
        !           238:            return -1;
        !           239:        }
        !           240:     }
        !           241:     conversation = SEND;
        !           242:     return 0;
        !           243: }
        !           244: 
        !           245: int
        !           246: api_exch_nextcommand()
        !           247: {
        !           248:     if (conversation != RECEIVE) {
        !           249:        if (enter_receive() == -1) {
        !           250:            return -1;
        !           251:        }
        !           252:     }
        !           253:     if (receive_state() == -1) {
        !           254:        return -1;
        !           255:     }
        !           256:     if (exch_state.opcode != EXCH_EXCH_COMMAND) {
        !           257:        WHO_ARE_WE();
        !           258:        fprintf(stderr, "Expected a %s exchange, received a %s exchange.\n",
        !           259:            exch_to_ascii(EXCH_EXCH_COMMAND), exch_to_ascii(exch_state.opcode));
        !           260:        return -1;
        !           261:     }
        !           262:     return exch_state.command_or_type;
        !           263: }
        !           264: 
        !           265: 
        !           266: int
        !           267: api_exch_incommand(command)
        !           268: int command;
        !           269: {
        !           270:     int i;
        !           271: 
        !           272:     if ((i = api_exch_nextcommand()) == -1) {
        !           273:        return -1;
        !           274:     }
        !           275:     if (i != command) {
        !           276:        WHO_ARE_WE();
        !           277:        fprintf(stderr, "Expected API command 0x%x, got API command 0x%x.\n",
        !           278:                                command, i);
        !           279:        return -1;
        !           280:     }
        !           281:     return 0;
        !           282: }
        !           283: 
        !           284: 
        !           285: int
        !           286: api_exch_outcommand(command)
        !           287: int command;
        !           288: {
        !           289:     if (conversation != SEND) {
        !           290:        if (enter_send() == -1) {
        !           291:            return -1;
        !           292:        }
        !           293:     }
        !           294:     exch_state.command_or_type = command;
        !           295:     exch_state.opcode = EXCH_EXCH_COMMAND;
        !           296:     if (send_state() == -1) {
        !           297:        return -1;
        !           298:     } else {
        !           299:        return 0;
        !           300:     }
        !           301: }
        !           302: 
        !           303: 
        !           304: int
        !           305: api_exch_outtype(type, length, location)
        !           306: int
        !           307:     type,
        !           308:     length;
        !           309: char
        !           310:     *location;
        !           311: {
        !           312:     int netleng = length;
        !           313: 
        !           314:     if (conversation != SEND) {
        !           315:        if (enter_send() == -1) {
        !           316:            return -1;
        !           317:        }
        !           318:     }
        !           319:     exch_state.opcode = EXCH_EXCH_TYPE;
        !           320:     exch_state.command_or_type = type;
        !           321:     exch_state.length = netleng;
        !           322:     if (send_state() == -1) {
        !           323:        return -1;
        !           324:     }
        !           325:     if (length) {
        !           326:        if (OBUFROOM() > length) {
        !           327:            OBUFADDBYTES(location, length);
        !           328:        } else {
        !           329:            if (outflush() == -1) {
        !           330:                return -1;
        !           331:            }
        !           332:            if (write(sock, location, length) != length) {
        !           333:                WHO_ARE_WE();
        !           334:                perror("write");
        !           335:                return -1;
        !           336:            }
        !           337:        }
        !           338:     }
        !           339:     return 0;
        !           340: }
        !           341: 
        !           342: 
        !           343: int
        !           344: api_exch_intype(type, length, location)
        !           345: int
        !           346:     type,
        !           347:     length;
        !           348: char
        !           349:     *location;
        !           350: {
        !           351:     int i, netleng = length;
        !           352: 
        !           353:     if (conversation != RECEIVE) {
        !           354:        if (enter_receive() == -1) {
        !           355:            return -1;
        !           356:        }
        !           357:     }
        !           358:     if (receive_state() == -1) {
        !           359:        return -1;
        !           360:     }
        !           361:     if (exch_state.opcode != EXCH_EXCH_TYPE) {
        !           362:        WHO_ARE_WE();
        !           363:        fprintf(stderr,
        !           364:            "Expected to receive a %s exchange, received a %s exchange.\n",
        !           365:            exch_to_ascii(EXCH_EXCH_TYPE), exch_to_ascii(exch_state.opcode));
        !           366:        return -1;
        !           367:     }
        !           368:     if (exch_state.command_or_type != type) {
        !           369:        WHO_ARE_WE();
        !           370:        fprintf(stderr, "Expected type 0x%x, got type 0x%x.\n",
        !           371:            type, exch_state.command_or_type);
        !           372:        return -1;
        !           373:     }
        !           374:     if (exch_state.length != netleng) {
        !           375:        fprintf(stderr, "Type 0x%x - expected length %d, received length %d.\n",
        !           376:                type, length, exch_state.length);
        !           377:        return -1;
        !           378:     }
        !           379:     if (iget(location, length) == -1) {
        !           380:        return -1;
        !           381:     }
        !           382:     return 0;
        !           383: }
        !           384: 
        !           385: int
        !           386: api_exch_flush()
        !           387: {
        !           388:     return outflush();
        !           389: }
        !           390: 
        !           391: int
        !           392: api_exch_init(sock_number, ourname)
        !           393: int sock_number;
        !           394: char *ourname;
        !           395: {
        !           396:     sock = sock_number;
        !           397:     strcpy(whoarewe, ourname);         /* For error messages */
        !           398: 
        !           399:     my_sequence = your_sequence = 0;
        !           400: 
        !           401:     conversation = CONTENTION;         /* We don't know which direction */
        !           402: 
        !           403:     IBUFRESET();
        !           404:     OBUFRESET();
        !           405: 
        !           406:     return 0;
        !           407: }

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