Annotation of embedaddon/libnet/sample/ntp.c, revision 1.1
1.1 ! misho 1: /*
! 2: * $Id: ntp.c,v 1.3 2004/02/20 18:53:49 mike Exp $
! 3: *
! 4: * libnet 1.1
! 5: * Build an NTP Packet
! 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: #include "./libnet_test.h"
! 37:
! 38: int
! 39: main(int argc, char **argv)
! 40: {
! 41: int c;
! 42: libnet_t *l;
! 43: u_long dst_ip;
! 44: libnet_ptag_t t;
! 45: char errbuf[LIBNET_ERRBUF_SIZE];
! 46:
! 47: printf("libnet 1.1 NTP packet shaping[raw -- autobuilding IP]\n");
! 48:
! 49: /*
! 50: * Initialize the library. Root priviledges are required.
! 51: */
! 52: l = libnet_init(
! 53: LIBNET_RAW4, /* injection type */
! 54: NULL, /* network interface */
! 55: errbuf); /* error buf */
! 56:
! 57: if (l == NULL)
! 58: {
! 59: fprintf(stderr, "libnet_init() failed: %s", errbuf);
! 60: exit(EXIT_FAILURE);
! 61: }
! 62:
! 63: dst_ip = 0;
! 64: while((c = getopt(argc, argv, "d:")) != EOF)
! 65: {
! 66: switch (c)
! 67: {
! 68: /*
! 69: * We expect the input to be of the form `ip.ip.ip.ip.port`. We
! 70: * point cp to the last dot of the IP address/port string and
! 71: * then seperate them with a NULL byte. The optarg now points to
! 72: * just the IP address, and cp points to the port.
! 73: */
! 74: case 'd':
! 75: if ((dst_ip = libnet_name2addr4(l, optarg, LIBNET_RESOLVE)) == -1)
! 76: {
! 77: fprintf(stderr, "Bad destination IP address: %s\n", optarg);
! 78: exit(1);
! 79: }
! 80: break;
! 81: }
! 82: }
! 83: if (!dst_ip)
! 84: {
! 85: usage(argv[0]);
! 86: exit(EXIT_FAILURE);
! 87: }
! 88:
! 89: /*
! 90: * Build the packet, remmebering that order IS important. We must
! 91: * build the packet from lowest protocol type on up as it would
! 92: * appear on the wire. So for our NTP packet:
! 93: *
! 94: * --------------------------------------------------------------------
! 95: * | IP | UDP | NTP |
! 96: * --------------------------------------------------------------------
! 97: * ^ ^ ^
! 98: * |-------------- | |
! 99: * libnet_build_ipv4()--| | |
! 100: * | |
! 101: * libnet_build_udp()-------| |
! 102: * |
! 103: * libnet_build_ntp()------------------------------|
! 104: */
! 105: t = libnet_build_ntp(
! 106: LIBNET_NTP_LI_AC, /* leap indicator */
! 107: LIBNET_NTP_VN_4, /* version */
! 108: LIBNET_NTP_MODE_S, /* mode */
! 109: LIBNET_NTP_STRATUM_PRIMARY, /* stratum */
! 110: 4, /* poll interval */
! 111: 1, /* precision */
! 112: 0xffff, /* delay interval */
! 113: 0xffff, /* delay fraction */
! 114: 0xffff, /* dispersion interval */
! 115: 0xffff, /* dispersion fraction */
! 116: LIBNET_NTP_REF_PPS, /* reference id */
! 117: 0x11, /* reference ts int */
! 118: 0x22, /* reference ts frac */
! 119: 0x33, /* originate ts int */
! 120: 0x44, /* originate ts frac */
! 121: 0x55, /* receive ts int */
! 122: 0x66, /* receive ts frac */
! 123: 0x77, /* transmit ts interval */
! 124: 0x88, /* transmit ts fraction */
! 125: NULL, /* payload */
! 126: 0, /* payload size */
! 127: l, /* libnet handle */
! 128: 0); /* libnet id */
! 129: if (t == -1)
! 130: {
! 131: fprintf(stderr, "Can't build NTP header: %s\n", libnet_geterror(l));
! 132: goto bad;
! 133: }
! 134:
! 135: libnet_seed_prand(l);
! 136: t = libnet_build_udp(
! 137: libnet_get_prand(LIBNET_PRu16), /* source port */
! 138: 123, /* NTP port */
! 139: LIBNET_UDP_H + LIBNET_NTP_H, /* UDP packet length */
! 140: 0, /* checksum */
! 141: NULL, /* payload */
! 142: 0, /* payload size */
! 143: l, /* libnet handle */
! 144: 0); /* libnet id */
! 145: if (t == -1)
! 146: {
! 147: fprintf(stderr, "Can't build UDP header: %s\n", libnet_geterror(l));
! 148: goto bad;
! 149: }
! 150:
! 151: t = libnet_autobuild_ipv4(
! 152: LIBNET_IPV4_H + LIBNET_UDP_H + LIBNET_NTP_H,/* packet length */
! 153: IPPROTO_UDP,
! 154: dst_ip,
! 155: l);
! 156: if (t == -1)
! 157: {
! 158: fprintf(stderr, "Can't build IP header: %s\n", libnet_geterror(l));
! 159: goto bad;
! 160: }
! 161:
! 162: /*
! 163: * Write it to the wire.
! 164: */
! 165:
! 166: fprintf(stderr, "l contains a %d byte packet\n", libnet_getpacket_size(l));
! 167: c = libnet_write(l);
! 168: if (c == -1)
! 169: {
! 170: fprintf(stderr, "Write error: %s\n", libnet_geterror(l));
! 171: goto bad;
! 172: }
! 173: else
! 174: {
! 175: fprintf(stderr, "Wrote %d byte NTP packet; check the wire.\n", c);
! 176: }
! 177: libnet_destroy(l);
! 178: return (EXIT_SUCCESS);
! 179: bad:
! 180: libnet_destroy(l);
! 181: return (EXIT_FAILURE);
! 182: }
! 183:
! 184:
! 185: void
! 186: usage(char *name)
! 187: {
! 188: fprintf(stderr,
! 189: "usage: %s -d destination_ip\n",
! 190: name);
! 191: }
! 192:
! 193: /* EOF */
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