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    1: /*
    2:  *  $Id: libnet_build_dhcp.c,v 1.1.1.1 2012/02/21 22:14:23 misho Exp $
    3:  *
    4:  *  libnet
    5:  *  libnet_build_dhcp.c - DHCP/BOOTP 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_dhcpv4(u_int8_t opcode, u_int8_t htype, u_int8_t hlen, 
   44: u_int8_t hopcount, u_int32_t xid, u_int16_t secs, u_int16_t flags,
   45: u_int32_t cip, u_int32_t yip, u_int32_t sip, u_int32_t gip, u_int8_t *chaddr,
   46: u_int8_t *sname, u_int8_t *file, u_int8_t *payload, u_int32_t payload_s,
   47: libnet_t *l, libnet_ptag_t ptag)
   48: {
   49:     u_int32_t n, h;
   50:     libnet_pblock_t *p; 
   51:     struct libnet_dhcpv4_hdr dhcp_hdr;
   52: 
   53:     if (l == NULL)
   54:     { 
   55:         return (-1);
   56:     } 
   57: 
   58:     n = LIBNET_DHCPV4_H + payload_s;
   59:     h = 0;          /* no checksum */
   60:  
   61:     /*
   62:      *  Find the existing protocol block if a ptag is specified, or create
   63:      *  a new one.
   64:      */
   65:     p = libnet_pblock_probe(l, ptag, n, LIBNET_PBLOCK_DHCPV4_H);
   66:     if (p == NULL)
   67:     {
   68:         return (-1);
   69:     }
   70: 
   71:     memset(&dhcp_hdr, 0, sizeof(dhcp_hdr));
   72:     dhcp_hdr.dhcp_opcode    = opcode;
   73:     dhcp_hdr.dhcp_htype     = htype;
   74:     dhcp_hdr.dhcp_hlen      = hlen;
   75:     dhcp_hdr.dhcp_hopcount  = hopcount;
   76:     dhcp_hdr.dhcp_xid       = htonl(xid);
   77:     dhcp_hdr.dhcp_secs      = htons(secs);
   78:     dhcp_hdr.dhcp_flags     = htons(flags);
   79:     dhcp_hdr.dhcp_cip       = htonl(cip);
   80:     dhcp_hdr.dhcp_yip       = htonl(yip);
   81:     dhcp_hdr.dhcp_sip       = htonl(sip);
   82:     dhcp_hdr.dhcp_gip       = htonl(gip);
   83: 
   84:     if (chaddr)
   85:     { 
   86:         memcpy(dhcp_hdr.dhcp_chaddr, chaddr, sizeof (dhcp_hdr.dhcp_chaddr));
   87:         dhcp_hdr.dhcp_chaddr[sizeof(dhcp_hdr.dhcp_chaddr) - 1] = 0;
   88:     }
   89:     else
   90:     {
   91:         memset(dhcp_hdr.dhcp_chaddr, 0, sizeof (dhcp_hdr.dhcp_chaddr));
   92:     }
   93:  
   94:     if (sname)
   95:     { 
   96:         memcpy(dhcp_hdr.dhcp_sname, sname, sizeof (dhcp_hdr.dhcp_sname));
   97:         dhcp_hdr.dhcp_sname[sizeof(dhcp_hdr.dhcp_sname) - 1] = 0;
   98:     }
   99:     else
  100:     {
  101:         memset(dhcp_hdr.dhcp_sname, 0, sizeof (dhcp_hdr.dhcp_sname));
  102:     }
  103: 
  104:     if (file)
  105:     {
  106:         memcpy(dhcp_hdr.dhcp_file, file, sizeof (dhcp_hdr.dhcp_file));
  107:         dhcp_hdr.dhcp_file[sizeof(dhcp_hdr.dhcp_file) - 1] = 0;
  108:     }
  109:     else
  110:     {
  111:         memset(dhcp_hdr.dhcp_file, 0, sizeof(dhcp_hdr.dhcp_file));
  112:     }
  113:     dhcp_hdr.dhcp_magic = htonl(DHCP_MAGIC);    /* should this be tunable? */
  114: 
  115:     n = libnet_pblock_append(l, p, (u_int8_t *)&dhcp_hdr, LIBNET_DHCPV4_H);
  116:     if (n == -1)
  117:     {
  118:         goto bad;
  119:     }
  120: 
  121:     if ((payload && !payload_s) || (!payload && payload_s))
  122:     {
  123:          snprintf(l->err_buf, LIBNET_ERRBUF_SIZE,
  124:                  "%s(): payload inconsistency\n", __func__);
  125:         goto bad;
  126:     }
  127:  
  128:     if (payload && payload_s)
  129:     {
  130:         n = libnet_pblock_append(l, p, payload, payload_s);
  131:         if (n == -1)
  132:         {
  133:             goto bad;
  134:         }
  135:     }
  136:  
  137:     return (ptag ? ptag : libnet_pblock_update(l, p, h, 
  138:             LIBNET_PBLOCK_DHCPV4_H));
  139: bad:
  140:     libnet_pblock_delete(l, p);
  141:     return (-1);
  142: }
  143: 
  144: libnet_ptag_t
  145: libnet_build_bootpv4(u_int8_t opcode, u_int8_t htype, u_int8_t hlen,
  146: u_int8_t hopcount, u_int32_t xid, u_int16_t secs, u_int16_t flags,
  147: u_int32_t cip, u_int32_t yip, u_int32_t sip, u_int32_t gip, u_int8_t *chaddr,
  148: u_int8_t *sname, u_int8_t *file, u_int8_t *payload, u_int32_t payload_s,
  149: libnet_t *l, libnet_ptag_t ptag)
  150: {
  151:     return (libnet_build_dhcpv4(opcode, htype, hlen, hopcount, xid, secs,
  152:         flags, cip, yip, sip, gip, chaddr, sname, file, payload, payload_s, 
  153:         l, ptag));
  154: }
  155: 
  156: /* EOF */