Return to lib.c CVS log

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

igmpproxy

    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: