dist/ipf/lib/tcpflags.c

   1 /*      $NetBSD$        */
   2
   3 /*
   4  * Copyright (C) 2001-2002 by Darren Reed.
   5  *
   6  * See the IPFILTER.LICENCE file for details on licencing.
   7  *
   8  * Id: tcpflags.c,v 1.3.4.1 2006/06/16 17:21:17 darrenr Exp
   9  */
  10
  11 #include "ipf.h"
  12
  13
  14 /*
  15  * ECN is a new addition to TCP - RFC 2481
  16  */
  17 #ifndef TH_ECN
  18 # define        TH_ECN  0x40
  19 #endif
  20 #ifndef TH_CWR
  21 # define        TH_CWR  0x80
  22 #endif
  23
  24 extern  char    flagset[];
  25 extern  u_char  flags[];
  26
  27
  28 u_char tcpflags(flgs)
  29 char *flgs;
  30 {
  31         u_char tcpf = 0;
  32         char *s, *t;
  33
  34         for (s = flgs; *s; s++) {
  35                 if (*s == 'W')
  36                         tcpf |= TH_CWR;
  37                 else {
  38                         if (!(t = strchr(flagset, *s))) {
  39                                 return 0;
  40                         }
  41                         tcpf |= flags[t - flagset];
  42                 }
  43         }
  44         return tcpf;
  45 }