usr/src/cmd/ipf/lib/common/tcpflags.c

   1 /*
   2  * Copyright (C) 1993-2001 by Darren Reed.
   3  *
   4  * See the IPFILTER.LICENCE file for details on licencing.
   5  *
   6  * $Id: tcpflags.c,v 1.3 2002/11/02 07:18:01 darrenr Exp $
   7  */
   8
   9 #include "ipf.h"
  10
  11
  12 /*
  13  * ECN is a new addition to TCP - RFC 2481
  14  */
  15 #ifndef TH_ECN
  16 # define        TH_ECN  0x40
  17 #endif
  18 #ifndef TH_CWR
  19 # define        TH_CWR  0x80
  20 #endif
  21
  22 extern  char    flagset[];
  23 extern  u_char  flags[];
  24
  25
  26 u_char tcpflags(flgs)
  27 char *flgs;
  28 {
  29         u_char tcpf = 0;
  30         char *s, *t;
  31
  32         for (s = flgs; *s; s++) {
  33                 if (*s == 'W')
  34                         tcpf |= TH_CWR;
  35                 else {
  36                         if (!(t = strchr(flagset, *s))) {
  37                                 return 0;
  38                         }
  39                         tcpf |= flags[t - flagset];
  40                 }
  41         }
  42         return tcpf;
  43 }