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Commit	Line	Data
	1	/*
	2	* Copyright (c) 2000-2002 Apple Computer, Inc. All rights reserved.
	3	*
	4	* @APPLE_LICENSE_HEADER_START@
	5	*
	6	* This file contains Original Code and/or Modifications of Original Code
	7	* as defined in and that are subject to the Apple Public Source License
	8	* Version 2.0 (the 'License'). You may not use this file except in
	9	* compliance with the License. Please obtain a copy of the License at
	10	* http://www.opensource.apple.com/apsl/ and read it before using this
	11	* file.
	12	*
	13	* The Original Code and all software distributed under the License are
	14	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
	15	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	16	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
	17	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	18	* Please see the License for the specific language governing rights and
	19	* limitations under the License.
	20	*
	21	* @APPLE_LICENSE_HEADER_END@
	22	*/
	23	/*
	24	* natd - Network Address Translation Daemon for FreeBSD.
	25	*
	26	* This software is provided free of charge, with no
	27	* warranty of any kind, either expressed or implied.
	28	* Use at your own risk.
	29	*
	30	* You may copy, modify and distribute this software (icmp.c) freely.
	31	*
	32	* Ari Suutari <suutari@iki.fi>
	33	*
	34	* Based upon:
	35	* $FreeBSD: src/sbin/natd/icmp.c,v 1.6 1999/08/28 00:13:45 peter Exp $
	36	*/
	37
	38	#include <stdlib.h>
	39	#include <stdio.h>
	40	#include <unistd.h>
	41	#include <string.h>
	42	#include <ctype.h>
	43
	44	#include <sys/types.h>
	45	#include <sys/socket.h>
	46	#include <sys/time.h>
	47	#include <errno.h>
	48	#include <signal.h>
	49
	50	#include <netdb.h>
	51
	52	#include <netinet/in.h>
	53	#include <netinet/in_systm.h>
	54	#include <netinet/ip.h>
	55	#include <netinet/ip_icmp.h>
	56
	57	#include <alias.h>
	58
	59	#include "natd.h"
	60
	61	int SendNeedFragIcmp (int sock, struct ip* failedDgram, int mtu)
	62	{
	63	char icmpBuf[IP_MAXPACKET];
	64	struct ip* ip;
	65	struct icmp* icmp;
	66	int icmpLen;
	67	int failBytes;
	68	int failHdrLen;
	69	struct sockaddr_in addr;
	70	int wrote;
	71	struct in_addr swap;
	72	/*
	73	* Don't send error if packet is
	74	* not the first fragment.
	75	*/
	76	if (ntohs (failedDgram->ip_off) & ~(IP_MF \| IP_DF))
	77	return 0;
	78	/*
	79	* Dont respond if failed datagram is ICMP.
	80	*/
	81	if (failedDgram->ip_p == IPPROTO_ICMP)
	82	return 0;
	83	/*
	84	* Start building the message.
	85	*/
	86	ip = (struct ip*) icmpBuf;
	87	icmp = (struct icmp*) (icmpBuf + sizeof (struct ip));
	88	/*
	89	* Complete ICMP part.
	90	*/
	91	icmp->icmp_type = ICMP_UNREACH;
	92	icmp->icmp_code = ICMP_UNREACH_NEEDFRAG;
	93	icmp->icmp_cksum = 0;
	94	icmp->icmp_void = 0;
	95	icmp->icmp_nextmtu = htons (mtu);
	96	/*
	97	* Copy header + 64 bits of original datagram.
	98	*/
	99	failHdrLen = (failedDgram->ip_hl << 2);
	100	failBytes = failedDgram->ip_len - failHdrLen;
	101	if (failBytes > 8)
	102	failBytes = 8;
	103
	104	failBytes += failHdrLen;
	105	icmpLen = ICMP_MINLEN + failBytes;
	106
	107	memcpy (&icmp->icmp_ip, failedDgram, failBytes);
	108	/*
	109	* Calculate checksum.
	110	*/
	111	icmp->icmp_cksum = PacketAliasInternetChecksum ((u_short*) icmp,
	112	icmpLen);
	113	/*
	114	* Add IP header using old IP header as template.
	115	*/
	116	memcpy (ip, failedDgram, sizeof (struct ip));
	117
	118	ip->ip_v = 4;
	119	ip->ip_hl = 5;
	120	ip->ip_len = htons (sizeof (struct ip) + icmpLen);
	121	ip->ip_p = IPPROTO_ICMP;
	122	ip->ip_tos = 0;
	123
	124	swap = ip->ip_dst;
	125	ip->ip_dst = ip->ip_src;
	126	ip->ip_src = swap;
	127
	128	PacketAliasIn ((char*) ip, IP_MAXPACKET);
	129
	130	addr.sin_family = AF_INET;
	131	addr.sin_addr = ip->ip_dst;
	132	addr.sin_port = 0;
	133	/*
	134	* Put packet into processing queue.
	135	*/
	136	wrote = sendto (sock,
	137	icmp,
	138	icmpLen,
	139	0,
	140	(struct sockaddr*) &addr,
	141	sizeof addr);
	142
	143	if (wrote != icmpLen)
	144	Warn ("Cannot send ICMP message.");
	145
	146	return 1;
	147	}
	148
	149