Return to libnet_build_udp.c CVS log

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

Annotation of embedaddon/libnet/src/libnet_build_udp.c, revision 1.1

1.1     ! misho       1: /*
        !             2:  *  $Id: libnet_build_udp.c,v 1.10 2004/01/21 19:01:29 mike Exp $
        !             3:  *
        !             4:  *  libnet
        !             5:  *  libnet_build_udp.c - UDP 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_udp(u_int16_t sp, u_int16_t dp, u_int16_t len, u_int16_t sum,
        !            44: u_int8_t *payload, u_int32_t payload_s, libnet_t *l, libnet_ptag_t ptag)
        !            45: {
        !            46:     u_int32_t n, h;
        !            47:     libnet_pblock_t *p;
        !            48:     struct libnet_udp_hdr udp_hdr;
        !            49: 
        !            50:     if (l == NULL)
        !            51:     { 
        !            52:         return (-1);
        !            53:     } 
        !            54: 
        !            55:     n = LIBNET_UDP_H + payload_s;               /* size of memory block */
        !            56:     h = len;                                    /* header length (for cksum) */
        !            57: 
        !            58:     /*
        !            59:      *  Find the existing protocol block if a ptag is specified, or create
        !            60:      *  a new one.
        !            61:      */
        !            62:     p = libnet_pblock_probe(l, ptag, n, LIBNET_PBLOCK_UDP_H);
        !            63:     if (p == NULL)
        !            64:     {
        !            65:         return (-1);
        !            66:     }
        !            67: 
        !            68:     memset(&udp_hdr, 0, sizeof(udp_hdr));
        !            69:     udp_hdr.uh_sport   = htons(sp);             /* source port */
        !            70:     udp_hdr.uh_dport   = htons(dp);             /* destination port */
        !            71:     udp_hdr.uh_ulen    = htons(h);              /* total length of UDP packet*/
        !            72:     udp_hdr.uh_sum     = (sum ? htons(sum) : 0);/* checksum */
        !            73: 
        !            74:     n = libnet_pblock_append(l, p, (u_int8_t *)&udp_hdr, LIBNET_UDP_H);
        !            75:     if (n == -1)
        !            76:     {
        !            77:         goto bad;
        !            78:     }
        !            79: 
        !            80:     if ((payload && !payload_s) || (!payload && payload_s))
        !            81:     {
        !            82:         snprintf(l->err_buf, LIBNET_ERRBUF_SIZE,
        !            83:                            "%s(): payload inconsistency\n", __func__);
        !            84:         goto bad;
        !            85:     }
        !            86:  
        !            87:     if (payload && payload_s)
        !            88:     {
        !            89:         n = libnet_pblock_append(l, p, payload, payload_s);
        !            90:         if (n == -1)
        !            91:         {
        !            92:             goto bad;
        !            93:         }
        !            94:     }
        !            95:  
        !            96:     if (sum == 0)
        !            97:     {
        !            98:         /*
        !            99:          *  If checksum is zero, by default libnet will compute a checksum
        !           100:          *  for the user.  The programmer can override this by calling
        !           101:          *  libnet_toggle_checksum(l, ptag, 1);
        !           102:          */
        !           103:         libnet_pblock_setflags(p, LIBNET_PBLOCK_DO_CHECKSUM);
        !           104:     }
        !           105:     return (ptag ? ptag : libnet_pblock_update(l, p, h, LIBNET_PBLOCK_UDP_H));
        !           106: bad:
        !           107:     libnet_pblock_delete(l, p);
        !           108:     return (-1);
        !           109: }
        !           110: 
        !           111: /* EOF */