diff options
Diffstat (limited to 'libnet/src/libnet_build_udp.c')
-rw-r--r-- | libnet/src/libnet_build_udp.c | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/libnet/src/libnet_build_udp.c b/libnet/src/libnet_build_udp.c new file mode 100644 index 0000000..276ed89 --- /dev/null +++ b/libnet/src/libnet_build_udp.c @@ -0,0 +1,98 @@ +/* + * $Id: libnet_build_udp.c,v 1.11 2004/04/13 17:32:28 mike Exp $ + * + * libnet + * libnet_build_udp.c - UDP packet assembler + * + * Copyright (c) 1998 - 2004 Mike D. Schiffman <mike@infonexus.com> + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + */ + +#if (HAVE_CONFIG_H) +#include "../include/config.h" +#endif +#if (!(_WIN32) || (__CYGWIN__)) +#include "../include/libnet.h" +#else +#include "../include/win32/libnet.h" +#endif + +libnet_ptag_t +libnet_build_udp(u_int16_t sp, u_int16_t dp, u_int16_t len, u_int16_t sum, +u_int8_t *payload, u_int32_t payload_s, libnet_t *l, libnet_ptag_t ptag) +{ + u_int32_t n, h; + libnet_pblock_t *p; + struct libnet_udp_hdr udp_hdr; + + if (l == NULL) + { + return (-1); + } + + n = LIBNET_UDP_H + payload_s; /* size of memory block */ + h = len; /* header length (for cksum) */ + + /* + * Find the existing protocol block if a ptag is specified, or create + * a new one. + */ + p = libnet_pblock_probe(l, ptag, n, LIBNET_PBLOCK_UDP_H); + if (p == NULL) + { + return (-1); + } + + memset(&udp_hdr, 0, sizeof(udp_hdr)); + udp_hdr.uh_sport = htons(sp); /* source port */ + udp_hdr.uh_dport = htons(dp); /* destination port */ + udp_hdr.uh_ulen = htons(h); /* total length of UDP packet*/ + udp_hdr.uh_sum = (sum ? htons(sum) : 0);/* checksum */ + + n = libnet_pblock_append(l, p, (u_int8_t *)&udp_hdr, LIBNET_UDP_H); + if (n == -1) + { + goto bad; + } + + /* boilerplate payload sanity check / append macro */ + LIBNET_DO_PAYLOAD(l, p); + + if (sum == 0) + { + /* + * If checksum is zero, by default libnet will compute a checksum + * for the user. The programmer can override this by calling + * libnet_toggle_checksum(l, ptag, 1); + */ + libnet_pblock_setflags(p, LIBNET_PBLOCK_DO_CHECKSUM); + } + return (ptag ? ptag : libnet_pblock_update(l, p, h, LIBNET_PBLOCK_UDP_H)); +bad: + libnet_pblock_delete(l, p); + return (-1); +} + +/* EOF */ |