332 lines
7.1 KiB
C
332 lines
7.1 KiB
C
/* $NetBSD: ip4_frag_1.c,v 1.2 2010/10/03 19:41:25 rmind Exp $ */
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/*-
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* Copyright (c) 2010 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software developed for The NetBSD Foundation
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* by Mindaugas Rasiukevicius <rmind at NetBSD org>.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Test various cases of IPv4 reassembly.
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*/
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#include <sys/cdefs.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <stddef.h>
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#include <unistd.h>
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#include <netdb.h>
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#include <assert.h>
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#include <err.h>
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#include <sys/socket.h>
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#include <netinet/in_systm.h>
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#include <netinet/in.h>
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#include <netinet/ip.h>
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#include <netinet/udp.h>
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#include <netinet/ip_icmp.h>
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#include <arpa/inet.h>
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#define IP_SIZE sizeof(struct ip)
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#define ICMP_SIZE offsetof(struct icmp, icmp_ip)
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static void *
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xalloc(size_t sz)
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{
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void *ptr = calloc(1, sz);
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if (ptr == NULL) {
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err(EXIT_FAILURE, "calloc");
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}
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return ptr;
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}
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static int
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create_socket(void)
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{
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int s, val = 1;
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s = socket(AF_INET, SOCK_RAW, IPPROTO_RAW);
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if (s == -1) {
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err(EXIT_FAILURE, "socket");
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}
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if (setsockopt(s, IPPROTO_IP, IP_HDRINCL, &val, sizeof(val)) == -1) {
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err(EXIT_FAILURE, "setsockopt");
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}
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return s;
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}
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void *
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create_ip_packet(in_addr_t target, int foff, size_t addlen)
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{
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struct ip *ip;
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unsigned int n;
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uint8_t *data;
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int first;
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/* Header at zero offset - first fragment. */
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first = ((foff & IP_MF) == 0);
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if (first) {
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assert(addlen >= ICMP_SIZE);
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addlen -= ICMP_SIZE;
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}
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ip = xalloc(IP_SIZE + addlen);
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/*
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* IP header.
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* Note: ip_len and ip_off shall be in host byte order.
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*/
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ip->ip_v = IPVERSION;
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ip->ip_hl = 5;
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ip->ip_tos = 0;
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ip->ip_len = (5 << 2) + addlen;
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ip->ip_id = htons(1);
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ip->ip_off = foff;
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ip->ip_ttl = 64;
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ip->ip_p = IPPROTO_ICMP;
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ip->ip_sum = 0;
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ip->ip_src.s_addr = INADDR_ANY;
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ip->ip_dst.s_addr = target;
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/* Fill in some data. */
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data = (void *)(ip + 1);
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if (first) {
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struct icmp *icmp = (void *)data;
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icmp->icmp_type = ICMP_ECHO;
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icmp->icmp_code = 0;
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icmp->icmp_cksum = 0;
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n = ICMP_SIZE;
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} else {
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n = 0;
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}
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for (data += n; n < addlen; n++) {
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*data = (0xf & n);
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data++;
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}
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return (void *)ip;
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}
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void
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send_packet(int s, void *p, in_addr_t target)
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{
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struct ip *ip = (struct ip *)p;
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struct sockaddr_in addr;
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ssize_t ret;
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memset(&addr, 0, sizeof(addr));
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addr.sin_family = AF_INET;
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addr.sin_addr.s_addr = target;
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/* Note: total length was set host byte-order. */
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ret = sendto(s, p, ip->ip_len, 0,
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(struct sockaddr *)&addr, sizeof(struct sockaddr_in));
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if (ret == -1) {
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err(EXIT_FAILURE, "sendto");
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}
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free(p);
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}
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void
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test_case_0(int sock, in_addr_t target)
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{
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void *p;
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/*
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* Case 0: normal reassembly.
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* => IP_STAT_FRAGMENTS
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*/
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p = create_ip_packet(target, 0 | IP_MF, 1480);
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send_packet(sock, p, target);
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p = create_ip_packet(target, 185, 1480);
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send_packet(sock, p, target);
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}
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void
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test_case_1(int sock, in_addr_t target)
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{
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void *p;
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/*
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* Case 1: ip_len of the first fragment and ip_off + hlen of other
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* fragments should be at least 68 (IP_MINFRAGSIZE - 1) bytes.
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* => IP_STAT_BADFRAGS (malformed)
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*/
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/* 20 + 48 == 68, OK */
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p = create_ip_packet(target, 0 | IP_MF, 48);
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send_packet(sock, p, target);
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/* 20 + (5 * 8) = 60 < 68, ERR */
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p = create_ip_packet(target, 6 - 1, 8);
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send_packet(sock, p, target);
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}
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void
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test_case_2(int sock, in_addr_t target)
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{
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void *p;
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struct ip *ip;
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/*
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* Case 2: mismatch of TOS.
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* => IP_STAT_BADFRAGS (malformed)
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*/
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p = create_ip_packet(target, 0 | IP_MF, 48);
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ip = (struct ip *)p;
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ip->ip_tos = 123;
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send_packet(sock, p, target);
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p = create_ip_packet(target, 6, 48);
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send_packet(sock, p, target);
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}
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void
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test_case_3(int sock, in_addr_t target)
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{
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void *p;
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/*
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* Case 3: data length is not multiple of 8 bytes.
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* => IP_STAT_BADFRAGS (malformed)
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*/
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p = create_ip_packet(target, 0 | IP_MF, 48);
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send_packet(sock, p, target);
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/* (48 + 1) & 0x7 != 0, ERR */
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p = create_ip_packet(target, 6, 48 + 1);
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send_packet(sock, p, target);
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}
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void
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test_case_4(int sock, in_addr_t target)
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{
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void *p;
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/*
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* Case 4: fragment covering previous (duplicate).
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* => IP_STAT_FRAGDROPPED (dup, out of space)
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*/
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p = create_ip_packet(target, 0 | IP_MF, 48);
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send_packet(sock, p, target);
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p = create_ip_packet(target, 6 | IP_MF, 96);
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send_packet(sock, p, target);
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p = create_ip_packet(target, 6, 48);
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send_packet(sock, p, target);
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}
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void
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test_case_5(int sock, in_addr_t target)
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{
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void *p;
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int cnt, left, off;
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/*
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* Case 5: construct packet larger than IP_MAXPACKET.
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* => IP_STAT_TOOLONG (with length > max ip packet size)
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*/
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/*
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* Assumptions:
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* - 1500 MTU. Minus IP header - 1480.
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* - Bytes left: 65535 - (1480 * 44) = 415.
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*/
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cnt = IP_MAXPACKET / 1480;
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left = IP_MAXPACKET - (1480 * cnt);
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left = (left / 8) * 8;
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for (off = 0; cnt != 0; cnt--) {
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p = create_ip_packet(target, off | IP_MF, 1480);
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send_packet(sock, p, target);
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off += (1480 >> 3);
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}
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/* Add 8 bytes and thus cross IP_MAXPACKET limit. */
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p = create_ip_packet(target, off, left + 8);
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send_packet(sock, p, target);
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}
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void
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test_case_6(int sock, in_addr_t target)
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{
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struct ip *ip;
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void *p;
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/*
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* Case 6: cause a fragment timeout.
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* => IP_STAT_FRAGTIMEOUT (fragments dropped after timeout)
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*/
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p = create_ip_packet(target, 0 | IP_MF, 48);
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ip = (struct ip *)p;
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ip->ip_id = htons(321);
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send_packet(sock, p, target);
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/*
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* Missing non-MF packet - timeout.
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*/
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}
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int
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main(int argc, char **argv)
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{
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struct hostent *he;
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in_addr_t target;
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int sock;
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if (argc < 2) {
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printf("%s: <target host>\n", argv[0]);
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exit(EXIT_SUCCESS);
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}
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he = gethostbyname(argv[1]);
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if (he == NULL) {
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err(EXIT_FAILURE, "gethostbyname");
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}
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memcpy(&target, he->h_addr, sizeof(target));
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sock = create_socket();
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test_case_0(sock, target);
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test_case_1(sock, target);
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test_case_2(sock, target);
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test_case_3(sock, target);
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test_case_4(sock, target);
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test_case_5(sock, target);
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test_case_6(sock, target);
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close(sock);
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return 0;
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}
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