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Annotation of 43BSDTahoe/ucb/telnet/Source/network.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[] = "@(#)network.c  1.11 (Berkeley) 3/8/88";
        !            15: #endif /* not lint */
        !            16: 
        !            17: #include <sys/types.h>
        !            18: #include <sys/socket.h>
        !            19: #include <sys/time.h>
        !            20: 
        !            21: #include <errno.h>
        !            22: 
        !            23: #include <arpa/telnet.h>
        !            24: 
        !            25: #include "ring.h"
        !            26: 
        !            27: #include "defines.h"
        !            28: #include "externs.h"
        !            29: #include "fdset.h"
        !            30: 
        !            31: Ring   netoring, netiring;
        !            32: char   netobuf[2*BUFSIZ], netibuf[BUFSIZ];
        !            33: 
        !            34: /*
        !            35:  * Initialize internal network data structures.
        !            36:  */
        !            37: 
        !            38: init_network()
        !            39: {
        !            40:     ring_init(&netoring, netobuf, sizeof netobuf);
        !            41:     ring_init(&netiring, netibuf, sizeof netibuf);
        !            42:     NetTrace = stdout;
        !            43: }
        !            44: 
        !            45: 
        !            46: /*
        !            47:  * Check to see if any out-of-band data exists on a socket (for
        !            48:  * Telnet "synch" processing).
        !            49:  */
        !            50: 
        !            51: int
        !            52: stilloob()
        !            53: {
        !            54:     static struct timeval timeout = { 0 };
        !            55:     fd_set     excepts;
        !            56:     int value;
        !            57: 
        !            58:     do {
        !            59:        FD_ZERO(&excepts);
        !            60:        FD_SET(net, &excepts);
        !            61:        value = select(net+1, (fd_set *)0, (fd_set *)0, &excepts, &timeout);
        !            62:     } while ((value == -1) && (errno == EINTR));
        !            63: 
        !            64:     if (value < 0) {
        !            65:        perror("select");
        !            66:        quit();
        !            67:     }
        !            68:     if (FD_ISSET(net, &excepts)) {
        !            69:        return 1;
        !            70:     } else {
        !            71:        return 0;
        !            72:     }
        !            73: }
        !            74: 
        !            75: 
        !            76: /*
        !            77:  *  setneturg()
        !            78:  *
        !            79:  *     Sets "neturg" to the current location.
        !            80:  */
        !            81: 
        !            82: void
        !            83: setneturg()
        !            84: {
        !            85:     ring_mark(&netoring);
        !            86: }
        !            87: 
        !            88: 
        !            89: /*
        !            90:  *  netflush
        !            91:  *             Send as much data as possible to the network,
        !            92:  *     handling requests for urgent data.
        !            93:  *
        !            94:  *             The return value indicates whether we did any
        !            95:  *     useful work.
        !            96:  */
        !            97: 
        !            98: 
        !            99: int
        !           100: netflush()
        !           101: {
        !           102:     register int n, n1;
        !           103: 
        !           104:     if ((n1 = n = ring_full_consecutive(&netoring)) > 0) {
        !           105:        if (!ring_at_mark(&netoring)) {
        !           106:            n = send(net, netoring.consume, n, 0);      /* normal write */
        !           107:        } else {
        !           108:            /*
        !           109:             * In 4.2 (and 4.3) systems, there is some question about
        !           110:             * what byte in a sendOOB operation is the "OOB" data.
        !           111:             * To make ourselves compatible, we only send ONE byte
        !           112:             * out of band, the one WE THINK should be OOB (though
        !           113:             * we really have more the TCP philosophy of urgent data
        !           114:             * rather than the Unix philosophy of OOB data).
        !           115:             */
        !           116:            n = send(net, netoring.consume, 1, MSG_OOB);/* URGENT data */
        !           117:        }
        !           118:     }
        !           119:     if (n < 0) {
        !           120:        if (errno != ENOBUFS && errno != EWOULDBLOCK) {
        !           121:            setcommandmode();
        !           122:            perror(hostname);
        !           123:            NetClose(net);
        !           124:            ring_clear_mark(&netoring);
        !           125:            longjmp(peerdied, -1);
        !           126:            /*NOTREACHED*/
        !           127:        }
        !           128:        n = 0;
        !           129:     }
        !           130:     if (netdata && n) {
        !           131:        Dump('>', netoring.consume, n);
        !           132:     }
        !           133:     if (n) {
        !           134:        ring_consumed(&netoring, n);
        !           135:        /*
        !           136:         * If we sent all, and more to send, then recurse to pick
        !           137:         * up the other half.
        !           138:         */
        !           139:        if ((n1 == n) && ring_full_consecutive(&netoring)) {
        !           140:            (void) netflush();
        !           141:        }
        !           142:        return 1;
        !           143:     } else {
        !           144:        return 0;
        !           145:     }
        !           146: }

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