Return to lib.c CVS log

Up to [ELWIX - Embedded LightWeight unIX -] / embedaddon / igmpproxy / src

Annotation of embedaddon/igmpproxy/src/lib.c, revision 1.1

1.1     ! misho       1: /*
        !             2: **  igmpproxy - IGMP proxy based multicast router 
        !             3: **  Copyright (C) 2005 Johnny Egeland <johnny@rlo.org>
        !             4: **
        !             5: **  This program is free software; you can redistribute it and/or modify
        !             6: **  it under the terms of the GNU General Public License as published by
        !             7: **  the Free Software Foundation; either version 2 of the License, or
        !             8: **  (at your option) any later version.
        !             9: **
        !            10: **  This program is distributed in the hope that it will be useful,
        !            11: **  but WITHOUT ANY WARRANTY; without even the implied warranty of
        !            12: **  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
        !            13: **  GNU General Public License for more details.
        !            14: **
        !            15: **  You should have received a copy of the GNU General Public License
        !            16: **  along with this program; if not, write to the Free Software
        !            17: **  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
        !            18: **
        !            19: **----------------------------------------------------------------------------
        !            20: **
        !            21: **  This software is derived work from the following software. The original
        !            22: **  source code has been modified from it's original state by the author
        !            23: **  of igmpproxy.
        !            24: **
        !            25: **  smcroute 0.92 - Copyright (C) 2001 Carsten Schill <carsten@cschill.de>
        !            26: **  - Licensed under the GNU General Public License, version 2
        !            27: **  
        !            28: **  mrouted 3.9-beta3 - COPYRIGHT 1989 by The Board of Trustees of 
        !            29: **  Leland Stanford Junior University.
        !            30: **  - Original license can be found in the Stanford.txt file.
        !            31: **
        !            32: */
        !            33: 
        !            34: #include "igmpproxy.h"
        !            35: 
        !            36: /*
        !            37:  * Exported variables.
        !            38:  */
        !            39: char s1[19];        /* buffers to hold the string representations  */
        !            40: char s2[19];        /* of IP addresses, to be passed to inet_fmt() */
        !            41: char s3[19];        /* or inet_fmts().                             */
        !            42: char s4[19];
        !            43:             
        !            44: /*
        !            45: ** Formats 'InAdr' into a dotted decimal string. 
        !            46: **
        !            47: ** returns: - pointer to 'St'
        !            48: **          
        !            49: */
        !            50: char *fmtInAdr( char *St, struct in_addr InAdr ) {
        !            51:     sprintf( St, "%u.%u.%u.%u", 
        !            52:              ((uint8_t *)&InAdr.s_addr)[ 0 ],
        !            53:              ((uint8_t *)&InAdr.s_addr)[ 1 ],
        !            54:              ((uint8_t *)&InAdr.s_addr)[ 2 ],
        !            55:              ((uint8_t *)&InAdr.s_addr)[ 3 ] );
        !            56: 
        !            57:     return St;
        !            58: }
        !            59: 
        !            60: /*
        !            61:  * Convert an IP address in u_long (network) format into a printable string.
        !            62:  */
        !            63: char *inetFmt(uint32_t addr, char *s) {
        !            64:     register u_char *a;
        !            65: 
        !            66:     a = (u_char *)&addr;
        !            67:     sprintf(s, "%u.%u.%u.%u", a[0], a[1], a[2], a[3]);
        !            68:     return(s);
        !            69: }
        !            70: 
        !            71: 
        !            72: /*
        !            73:  * Convert an IP subnet number in u_long (network) format into a printable
        !            74:  * string including the netmask as a number of bits.
        !            75:  */
        !            76: char *inetFmts(uint32_t addr, uint32_t mask, char *s) {
        !            77:     register u_char *a, *m;
        !            78:     int bits;
        !            79: 
        !            80:     if ((addr == 0) && (mask == 0)) {
        !            81:         sprintf(s, "default");
        !            82:         return(s);
        !            83:     }
        !            84:     a = (u_char *)&addr;
        !            85:     m = (u_char *)&mask;
        !            86:     bits = 33 - ffs(ntohl(mask));
        !            87: 
        !            88:     if (m[3] != 0) sprintf(s, "%u.%u.%u.%u/%d", a[0], a[1], a[2], a[3],
        !            89:                            bits);
        !            90:     else if (m[2] != 0) sprintf(s, "%u.%u.%u/%d",    a[0], a[1], a[2], bits);
        !            91:     else if (m[1] != 0) sprintf(s, "%u.%u/%d",       a[0], a[1], bits);
        !            92:     else                sprintf(s, "%u/%d",          a[0], bits);
        !            93: 
        !            94:     return(s);
        !            95: }
        !            96: 
        !            97: /*
        !            98:  * inet_cksum extracted from:
        !            99:  *                     P I N G . C
        !           100:  *
        !           101:  * Author -
        !           102:  *     Mike Muuss
        !           103:  *     U. S. Army Ballistic Research Laboratory
        !           104:  *     December, 1983
        !           105:  * Modified at Uc Berkeley
        !           106:  *
        !           107:  * (ping.c) Status -
        !           108:  *     Public Domain.  Distribution Unlimited.
        !           109:  *
        !           110:  *                     I N _ C K S U M
        !           111:  *
        !           112:  * Checksum routine for Internet Protocol family headers (C Version)
        !           113:  *
        !           114:  */
        !           115: uint16_t inetChksum(uint16_t *addr, int len) {
        !           116:     register int nleft = len;
        !           117:     register uint16_t *w = addr;
        !           118:     uint16_t answer = 0;
        !           119:     register int32_t sum = 0;
        !           120: 
        !           121:     /*
        !           122:      *  Our algorithm is simple, using a 32 bit accumulator (sum),
        !           123:      *  we add sequential 16 bit words to it, and at the end, fold
        !           124:      *  back all the carry bits from the top 16 bits into the lower
        !           125:      *  16 bits.
        !           126:      */
        !           127:     while (nleft > 1) {
        !           128:         sum += *w++;
        !           129:         nleft -= 2;
        !           130:     }
        !           131: 
        !           132:     /* mop up an odd byte, if necessary */
        !           133:     if (nleft == 1) {
        !           134:         *(uint8_t *) (&answer) = *(uint8_t *)w ;
        !           135:         sum += answer;
        !           136:     }
        !           137: 
        !           138:     /*
        !           139:      * add back carry outs from top 16 bits to low 16 bits
        !           140:      */
        !           141:     sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */
        !           142:     sum += (sum >> 16);         /* add carry */
        !           143:     answer = ~sum;              /* truncate to 16 bits */
        !           144:     return(answer);
        !           145: }
        !           146: 
        !           147: 
        !           148: