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    1: /*
    2:  *  $Id: libnet_build_mpls.c,v 1.1.1.1 2012/02/21 22:14:23 misho Exp $
    3:  *
    4:  *  libnet
    5:  *  libnet_build_mpls.c - MPLS packet assembler
    6:  *
    7:  *  Copyright (c) 1998 - 2004 Mike D. Schiffman <mike@infonexus.com>
    8:  *  All rights reserved.
    9:  *
   10:  * Redistribution and use in source and binary forms, with or without
   11:  * modification, are permitted provided that the following conditions
   12:  * are met:
   13:  * 1. Redistributions of source code must retain the above copyright
   14:  *    notice, this list of conditions and the following disclaimer.
   15:  * 2. Redistributions in binary form must reproduce the above copyright
   16:  *    notice, this list of conditions and the following disclaimer in the
   17:  *    documentation and/or other materials provided with the distribution.
   18:  *
   19:  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   20:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   21:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   22:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   23:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   24:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   25:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   26:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   27:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   28:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   29:  * SUCH DAMAGE.
   30:  *
   31:  */
   32: 
   33: #if (HAVE_CONFIG_H)
   34: #include "../include/config.h"
   35: #endif
   36: #if (!(_WIN32) || (__CYGWIN__)) 
   37: #include "../include/libnet.h"
   38: #else
   39: #include "../include/win32/libnet.h"
   40: #endif
   41: 
   42: libnet_ptag_t
   43: libnet_build_mpls(u_int32_t label, u_int8_t experimental, u_int8_t bos, 
   44: u_int8_t ttl, u_int8_t *payload, u_int32_t payload_s, libnet_t *l,
   45: libnet_ptag_t ptag)
   46: {
   47:     u_int32_t n, h;
   48:     libnet_pblock_t *p;
   49:     struct libnet_mpls_hdr mpls_hdr;
   50: 
   51:     if (l == NULL)
   52:     { 
   53:         return (-1);
   54:     } 
   55: 
   56:     n = LIBNET_MPLS_H + payload_s;
   57:     h = 0;
   58: 
   59:     /*
   60:      *  Find the existing protocol block if a ptag is specified, or create
   61:      *  a new one.
   62:      */
   63:     p = libnet_pblock_probe(l, ptag, n, LIBNET_PBLOCK_MPLS_H);
   64:     if (p == NULL)
   65:     {
   66:         return (-1);
   67:     }
   68: 
   69:     memset(&mpls_hdr, 0, sizeof(mpls_hdr));
   70:     mpls_hdr.mpls_les = htonl((((label & 0x000fffff) << 12) |
   71:                               ((experimental & 0x07) <<  9) |
   72:                               ((bos & 0x01)          <<  8) |
   73:                               ((ttl & 0xff))));
   74: 
   75:     n = libnet_pblock_append(l, p, (u_int8_t *)&mpls_hdr, LIBNET_MPLS_H);
   76:     if (n == -1)
   77:     {
   78:         goto bad;
   79:     }
   80: 
   81:     if ((payload && !payload_s) || (!payload && payload_s))
   82:     {
   83:          snprintf(l->err_buf, LIBNET_ERRBUF_SIZE,
   84: 			     "%s(): payload inconsistency\n", __func__);
   85:         goto bad;
   86:     }
   87: 
   88:     if (payload && payload_s)
   89:     {
   90:         n = libnet_pblock_append(l, p, payload, payload_s);
   91:         if (n == -1)
   92:         {
   93:             goto bad;
   94:         }
   95:     }
   96: 
   97:     /*
   98:      *  The link offset is actually 4 bytes further into the header than
   99:      *  before (the MPLS header adds this 4 bytes).  We need to update the
  100:      *  link offset pointer. XXX - should we set this here?
  101:      *  Probably not.  We should make pblock_coalesce check the pblock type
  102:      *  and adjust accordingly.
  103:      */
  104:     l->link_offset += 4;
  105: 
  106:     return (ptag ? ptag : libnet_pblock_update(l, p, h, LIBNET_PBLOCK_MPLS_H));
  107: bad:
  108:     libnet_pblock_delete(l, p);
  109:     return (-1);
  110: }
  111: 
  112: /* EOF */