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Annotation of 43BSDReno/usr.bin/telnet/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 provided
        !             6:  * that: (1) source distributions retain this entire copyright notice and
        !             7:  * comment, and (2) distributions including binaries display the following
        !             8:  * acknowledgement:  ``This product includes software developed by the
        !             9:  * University of California, Berkeley and its contributors'' in the
        !            10:  * documentation or other materials provided with the distribution and in
        !            11:  * all advertising materials mentioning features or use of this software.
        !            12:  * Neither the name of the University nor the names of its contributors may
        !            13:  * be used to endorse or promote products derived from this software without
        !            14:  * specific prior written permission.
        !            15:  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
        !            16:  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
        !            17:  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
        !            18:  */
        !            19: 
        !            20: #ifndef lint
        !            21: static char sccsid[] = "@(#)network.c  1.15 (Berkeley) 6/28/90";
        !            22: #endif /* not lint */
        !            23: 
        !            24: #include <sys/types.h>
        !            25: #include <sys/socket.h>
        !            26: #include <sys/time.h>
        !            27: 
        !            28: #include <errno.h>
        !            29: 
        !            30: #include <arpa/telnet.h>
        !            31: 
        !            32: #include "ring.h"
        !            33: 
        !            34: #include "defines.h"
        !            35: #include "externs.h"
        !            36: #include "fdset.h"
        !            37: 
        !            38: Ring   netoring, netiring;
        !            39: char   netobuf[2*BUFSIZ], netibuf[BUFSIZ];
        !            40: 
        !            41: /*
        !            42:  * Initialize internal network data structures.
        !            43:  */
        !            44: 
        !            45: init_network()
        !            46: {
        !            47:     if (ring_init(&netoring, netobuf, sizeof netobuf) != 1) {
        !            48:        exit(1);
        !            49:     }
        !            50:     if (ring_init(&netiring, netibuf, sizeof netibuf) != 1) {
        !            51:        exit(1);
        !            52:     }
        !            53:     NetTrace = stdout;
        !            54: }
        !            55: 
        !            56: 
        !            57: /*
        !            58:  * Check to see if any out-of-band data exists on a socket (for
        !            59:  * Telnet "synch" processing).
        !            60:  */
        !            61: 
        !            62: int
        !            63: stilloob()
        !            64: {
        !            65:     static struct timeval timeout = { 0 };
        !            66:     fd_set     excepts;
        !            67:     int value;
        !            68: 
        !            69:     do {
        !            70:        FD_ZERO(&excepts);
        !            71:        FD_SET(net, &excepts);
        !            72:        value = select(net+1, (fd_set *)0, (fd_set *)0, &excepts, &timeout);
        !            73:     } while ((value == -1) && (errno == EINTR));
        !            74: 
        !            75:     if (value < 0) {
        !            76:        perror("select");
        !            77:        (void) quit();
        !            78:        /* NOTREACHED */
        !            79:     }
        !            80:     if (FD_ISSET(net, &excepts)) {
        !            81:        return 1;
        !            82:     } else {
        !            83:        return 0;
        !            84:     }
        !            85: }
        !            86: 
        !            87: 
        !            88: /*
        !            89:  *  setneturg()
        !            90:  *
        !            91:  *     Sets "neturg" to the current location.
        !            92:  */
        !            93: 
        !            94: void
        !            95: setneturg()
        !            96: {
        !            97:     ring_mark(&netoring);
        !            98: }
        !            99: 
        !           100: 
        !           101: /*
        !           102:  *  netflush
        !           103:  *             Send as much data as possible to the network,
        !           104:  *     handling requests for urgent data.
        !           105:  *
        !           106:  *             The return value indicates whether we did any
        !           107:  *     useful work.
        !           108:  */
        !           109: 
        !           110: 
        !           111: int
        !           112: netflush()
        !           113: {
        !           114:     register int n, n1;
        !           115: 
        !           116:     if ((n1 = n = ring_full_consecutive(&netoring)) > 0) {
        !           117:        if (!ring_at_mark(&netoring)) {
        !           118:            n = send(net, netoring.consume, n, 0);      /* normal write */
        !           119:        } else {
        !           120:            /*
        !           121:             * In 4.2 (and 4.3) systems, there is some question about
        !           122:             * what byte in a sendOOB operation is the "OOB" data.
        !           123:             * To make ourselves compatible, we only send ONE byte
        !           124:             * out of band, the one WE THINK should be OOB (though
        !           125:             * we really have more the TCP philosophy of urgent data
        !           126:             * rather than the Unix philosophy of OOB data).
        !           127:             */
        !           128:            n = send(net, netoring.consume, 1, MSG_OOB);/* URGENT data */
        !           129:        }
        !           130:     }
        !           131:     if (n < 0) {
        !           132:        if (errno != ENOBUFS && errno != EWOULDBLOCK) {
        !           133:            setcommandmode();
        !           134:            perror(hostname);
        !           135:            (void)NetClose(net);
        !           136:            ring_clear_mark(&netoring);
        !           137:            longjmp(peerdied, -1);
        !           138:            /*NOTREACHED*/
        !           139:        }
        !           140:        n = 0;
        !           141:     }
        !           142:     if (netdata && n) {
        !           143:        Dump('>', netoring.consume, n);
        !           144:     }
        !           145:     if (n) {
        !           146:        ring_consumed(&netoring, n);
        !           147:        /*
        !           148:         * If we sent all, and more to send, then recurse to pick
        !           149:         * up the other half.
        !           150:         */
        !           151:        if ((n1 == n) && ring_full_consecutive(&netoring)) {
        !           152:            (void) netflush();
        !           153:        }
        !           154:        return 1;
        !           155:     } else {
        !           156:        return 0;
        !           157:     }
        !           158: }

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