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

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: