526 lines
14 KiB
C
526 lines
14 KiB
C
/*
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* Copyright (c) 1982, 1986, 1989 Regents of the University of California.
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* All rights reserved.
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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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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* from: @(#)ip_icmp.c 7.15 (Berkeley) 4/20/91
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* $Id: ip_icmp.c,v 1.4 1993/12/18 00:41:56 mycroft Exp $
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/malloc.h>
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#include <sys/mbuf.h>
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#include <sys/protosw.h>
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#include <sys/socket.h>
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#include <sys/time.h>
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#include <sys/kernel.h>
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#include <net/route.h>
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#include <net/if.h>
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#include <netinet/in.h>
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#include <netinet/in_systm.h>
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#include <netinet/in_var.h>
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#include <netinet/ip.h>
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#include <netinet/ip_icmp.h>
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#include <netinet/icmp_var.h>
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/*
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* ICMP routines: error generation, receive packet processing, and
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* routines to turnaround packets back to the originator, and
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* host table maintenance routines.
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*/
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#ifdef ICMPPRINTFS
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int icmpprintfs = 0;
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#endif
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extern struct protosw inetsw[];
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/*
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* Generate an error packet of type error
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* in response to bad packet ip.
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*/
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/*VARARGS3*/
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icmp_error(n, type, code, dest)
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struct mbuf *n;
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int type, code;
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struct in_addr dest;
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{
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register struct ip *oip = mtod(n, struct ip *), *nip;
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register unsigned oiplen = oip->ip_hl << 2;
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register struct icmp *icp;
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register struct mbuf *m;
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unsigned icmplen;
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#ifdef ICMPPRINTFS
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if (icmpprintfs)
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printf("icmp_error(%x, %d, %d)\n", oip, type, code);
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#endif
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if (type != ICMP_REDIRECT)
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icmpstat.icps_error++;
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/*
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* Don't send error if not the first fragment of message.
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* Don't error if the old packet protocol was ICMP
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* error message, only known informational types.
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*/
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if (oip->ip_off &~ (IP_MF|IP_DF))
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goto freeit;
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if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT &&
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n->m_len >= oiplen + ICMP_MINLEN &&
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!ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiplen))->icmp_type)) {
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icmpstat.icps_oldicmp++;
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goto freeit;
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}
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#ifdef MULTICAST
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/* Don't send error in response to a multicast or broadcast packet */
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if (n->m_flags & (M_MCAST | M_BCAST))
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goto freeit;
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#endif
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/*
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* First, formulate icmp message
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*/
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m = m_gethdr(M_DONTWAIT, MT_HEADER);
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if (m == NULL)
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goto freeit;
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icmplen = oiplen + min(8, oip->ip_len);
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m->m_len = icmplen + ICMP_MINLEN;
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MH_ALIGN(m, m->m_len);
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icp = mtod(m, struct icmp *);
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if ((u_int)type > ICMP_MAXTYPE)
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panic("icmp_error");
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icmpstat.icps_outhist[type]++;
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icp->icmp_type = type;
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if (type == ICMP_REDIRECT)
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icp->icmp_gwaddr = dest;
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else
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icp->icmp_void = 0;
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if (type == ICMP_PARAMPROB) {
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icp->icmp_pptr = code;
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code = 0;
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}
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icp->icmp_code = code;
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bcopy((caddr_t)oip, (caddr_t)&icp->icmp_ip, icmplen);
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nip = &icp->icmp_ip;
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nip->ip_len = htons((u_short)(nip->ip_len + oiplen));
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/*
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* Now, copy old ip header (without options)
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* in front of icmp message.
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*/
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if (m->m_data - sizeof(struct ip) < m->m_pktdat)
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panic("icmp len");
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m->m_data -= sizeof(struct ip);
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m->m_len += sizeof(struct ip);
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m->m_pkthdr.len = m->m_len;
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m->m_pkthdr.rcvif = n->m_pkthdr.rcvif;
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nip = mtod(m, struct ip *);
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bcopy((caddr_t)oip, (caddr_t)nip, oiplen);
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nip->ip_len = m->m_len;
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nip->ip_hl = sizeof(struct ip) >> 2;
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nip->ip_p = IPPROTO_ICMP;
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icmp_reflect(m);
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freeit:
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m_freem(n);
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}
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static struct sockproto icmproto = { AF_INET, IPPROTO_ICMP };
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static struct sockaddr_in icmpsrc = { sizeof (struct sockaddr_in), AF_INET };
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static struct sockaddr_in icmpdst = { sizeof (struct sockaddr_in), AF_INET };
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static struct sockaddr_in icmpgw = { sizeof (struct sockaddr_in), AF_INET };
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struct sockaddr_in icmpmask = { 8, 0 };
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struct in_ifaddr *ifptoia();
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/*
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* Process a received ICMP message.
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*/
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icmp_input(m, hlen)
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register struct mbuf *m;
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int hlen;
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{
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register struct icmp *icp;
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register struct ip *ip = mtod(m, struct ip *);
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int icmplen = ip->ip_len;
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register int i;
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struct in_ifaddr *ia;
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int (*ctlfunc)(), code;
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extern u_char ip_protox[];
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extern struct in_addr in_makeaddr();
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/*
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* Locate icmp structure in mbuf, and check
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* that not corrupted and of at least minimum length.
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*/
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#ifdef ICMPPRINTFS
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if (icmpprintfs)
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printf("icmp_input from %x, len %d\n", ip->ip_src, icmplen);
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#endif
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if (icmplen < ICMP_MINLEN) {
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icmpstat.icps_tooshort++;
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goto freeit;
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}
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i = hlen + MIN(icmplen, ICMP_ADVLENMIN);
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if (m->m_len < i && (m = m_pullup(m, i)) == 0) {
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icmpstat.icps_tooshort++;
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return;
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}
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ip = mtod(m, struct ip *);
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m->m_len -= hlen;
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m->m_data += hlen;
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icp = mtod(m, struct icmp *);
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if (in_cksum(m, icmplen)) {
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icmpstat.icps_checksum++;
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goto freeit;
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}
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m->m_len += hlen;
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m->m_data -= hlen;
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#ifdef ICMPPRINTFS
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/*
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* Message type specific processing.
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*/
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if (icmpprintfs)
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printf("icmp_input, type %d code %d\n", icp->icmp_type,
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icp->icmp_code);
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#endif
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if (icp->icmp_type > ICMP_MAXTYPE)
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goto raw;
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icmpstat.icps_inhist[icp->icmp_type]++;
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code = icp->icmp_code;
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switch (icp->icmp_type) {
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case ICMP_UNREACH:
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if (code > 5)
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goto badcode;
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code += PRC_UNREACH_NET;
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goto deliver;
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case ICMP_TIMXCEED:
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if (code > 1)
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goto badcode;
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code += PRC_TIMXCEED_INTRANS;
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goto deliver;
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case ICMP_PARAMPROB:
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if (code)
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goto badcode;
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code = PRC_PARAMPROB;
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goto deliver;
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case ICMP_SOURCEQUENCH:
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if (code)
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goto badcode;
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code = PRC_QUENCH;
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deliver:
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/*
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* Problem with datagram; advise higher level routines.
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*/
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if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
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icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) {
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icmpstat.icps_badlen++;
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goto freeit;
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}
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NTOHS(icp->icmp_ip.ip_len);
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#ifdef ICMPPRINTFS
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if (icmpprintfs)
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printf("deliver to protocol %d\n", icp->icmp_ip.ip_p);
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#endif
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icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
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if (ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput)
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(*ctlfunc)(code, (struct sockaddr *)&icmpsrc,
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(caddr_t) &icp->icmp_ip);
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break;
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badcode:
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icmpstat.icps_badcode++;
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break;
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case ICMP_ECHO:
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icp->icmp_type = ICMP_ECHOREPLY;
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goto reflect;
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case ICMP_TSTAMP:
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if (icmplen < ICMP_TSLEN) {
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icmpstat.icps_badlen++;
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break;
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}
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icp->icmp_type = ICMP_TSTAMPREPLY;
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icp->icmp_rtime = iptime();
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icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */
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goto reflect;
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case ICMP_IREQ:
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#define satosin(sa) ((struct sockaddr_in *)(sa))
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if (in_netof(ip->ip_src) == 0 &&
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(ia = ifptoia(m->m_pkthdr.rcvif)))
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ip->ip_src = in_makeaddr(in_netof(IA_SIN(ia)->sin_addr),
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in_lnaof(ip->ip_src));
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icp->icmp_type = ICMP_IREQREPLY;
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goto reflect;
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case ICMP_MASKREQ:
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if (icmplen < ICMP_MASKLEN ||
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(ia = ifptoia(m->m_pkthdr.rcvif)) == 0)
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break;
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icp->icmp_type = ICMP_MASKREPLY;
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icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr;
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if (ip->ip_src.s_addr == 0) {
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if (ia->ia_ifp->if_flags & IFF_BROADCAST)
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ip->ip_src = satosin(&ia->ia_broadaddr)->sin_addr;
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else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT)
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ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr;
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}
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reflect:
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ip->ip_len += hlen; /* since ip_input deducts this */
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icmpstat.icps_reflect++;
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icmpstat.icps_outhist[icp->icmp_type]++;
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icmp_reflect(m);
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return;
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case ICMP_REDIRECT:
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if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp)) {
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icmpstat.icps_badlen++;
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break;
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}
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/*
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* Short circuit routing redirects to force
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* immediate change in the kernel's routing
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* tables. The message is also handed to anyone
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* listening on a raw socket (e.g. the routing
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* daemon for use in updating its tables).
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*/
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icmpgw.sin_addr = ip->ip_src;
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icmpdst.sin_addr = icp->icmp_gwaddr;
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#ifdef ICMPPRINTFS
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if (icmpprintfs)
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printf("redirect dst %x to %x\n", icp->icmp_ip.ip_dst,
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icp->icmp_gwaddr);
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#endif
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if (code == ICMP_REDIRECT_NET || code == ICMP_REDIRECT_TOSNET) {
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u_long in_netof();
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icmpsrc.sin_addr =
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in_makeaddr(in_netof(icp->icmp_ip.ip_dst), INADDR_ANY);
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in_sockmaskof(icp->icmp_ip.ip_dst, &icmpmask);
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rtredirect((struct sockaddr *)&icmpsrc,
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(struct sockaddr *)&icmpdst,
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(struct sockaddr *)&icmpmask, RTF_GATEWAY,
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(struct sockaddr *)&icmpgw, (struct rtentry **)0);
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icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
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pfctlinput(PRC_REDIRECT_NET,
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(struct sockaddr *)&icmpsrc);
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} else {
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icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
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rtredirect((struct sockaddr *)&icmpsrc,
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(struct sockaddr *)&icmpdst,
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(struct sockaddr *)0, RTF_GATEWAY | RTF_HOST,
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(struct sockaddr *)&icmpgw, (struct rtentry **)0);
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pfctlinput(PRC_REDIRECT_HOST,
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(struct sockaddr *)&icmpsrc);
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}
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break;
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/*
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* No kernel processing for the following;
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* just fall through to send to raw listener.
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*/
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case ICMP_ECHOREPLY:
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case ICMP_TSTAMPREPLY:
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case ICMP_IREQREPLY:
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case ICMP_MASKREPLY:
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default:
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break;
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}
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raw:
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icmpsrc.sin_addr = ip->ip_src;
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icmpdst.sin_addr = ip->ip_dst;
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(void) raw_input(m, &icmproto, (struct sockaddr *)&icmpsrc,
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(struct sockaddr *)&icmpdst);
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return;
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freeit:
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m_freem(m);
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}
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/*
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* Reflect the ip packet back to the source
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*/
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icmp_reflect(m)
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struct mbuf *m;
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{
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register struct ip *ip = mtod(m, struct ip *);
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register struct in_ifaddr *ia;
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struct in_addr t;
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struct mbuf *opts = 0, *ip_srcroute();
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int optlen = (ip->ip_hl << 2) - sizeof(struct ip);
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t = ip->ip_dst;
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ip->ip_dst = ip->ip_src;
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/*
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* If the incoming packet was addressed directly to us,
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* use dst as the src for the reply. Otherwise (broadcast
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* or anonymous), use the address which corresponds
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* to the incoming interface.
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*/
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for (ia = in_ifaddr; ia; ia = ia->ia_next) {
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if (t.s_addr == IA_SIN(ia)->sin_addr.s_addr)
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break;
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if ((ia->ia_ifp->if_flags & IFF_BROADCAST) &&
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t.s_addr == satosin(&ia->ia_broadaddr)->sin_addr.s_addr)
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break;
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}
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if (ia == (struct in_ifaddr *)0)
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ia = ifptoia(m->m_pkthdr.rcvif);
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if (ia == (struct in_ifaddr *)0)
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ia = in_ifaddr;
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t = IA_SIN(ia)->sin_addr;
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ip->ip_src = t;
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ip->ip_ttl = MAXTTL;
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if (optlen > 0) {
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register u_char *cp;
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int opt, cnt;
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u_int len;
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/*
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* Retrieve any source routing from the incoming packet;
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* add on any record-route or timestamp options.
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*/
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cp = (u_char *) (ip + 1);
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if ((opts = ip_srcroute()) == 0 &&
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(opts = m_gethdr(M_DONTWAIT, MT_HEADER))) {
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opts->m_len = sizeof(struct in_addr);
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mtod(opts, struct in_addr *)->s_addr = 0;
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}
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if (opts) {
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#ifdef ICMPPRINTFS
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if (icmpprintfs)
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printf("icmp_reflect optlen %d rt %d => ",
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optlen, opts->m_len);
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#endif
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for (cnt = optlen; cnt > 0; cnt -= len, cp += len) {
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opt = cp[IPOPT_OPTVAL];
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if (opt == IPOPT_EOL)
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break;
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if (opt == IPOPT_NOP)
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len = 1;
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else {
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len = cp[IPOPT_OLEN];
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if (len <= 0 || len > cnt)
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break;
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}
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/*
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* should check for overflow, but it "can't happen"
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*/
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if (opt == IPOPT_RR || opt == IPOPT_TS) {
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bcopy((caddr_t)cp,
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mtod(opts, caddr_t) + opts->m_len, len);
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opts->m_len += len;
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}
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}
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if (opts->m_len % 4 != 0) {
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*(mtod(opts, caddr_t) + opts->m_len) = IPOPT_EOL;
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opts->m_len++;
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}
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#ifdef ICMPPRINTFS
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if (icmpprintfs)
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printf("%d\n", opts->m_len);
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#endif
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}
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/*
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* Now strip out original options by copying rest of first
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* mbuf's data back, and adjust the IP length.
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*/
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ip->ip_len -= optlen;
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ip->ip_hl = sizeof(struct ip) >> 2;
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m->m_len -= optlen;
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if (m->m_flags & M_PKTHDR)
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m->m_pkthdr.len -= optlen;
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optlen += sizeof(struct ip);
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bcopy((caddr_t)ip + optlen, (caddr_t)(ip + 1),
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(unsigned)(m->m_len - sizeof(struct ip)));
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}
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m->m_flags &= ~(M_BCAST|M_MCAST);
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icmp_send(m, opts);
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if (opts)
|
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(void)m_free(opts);
|
|
}
|
|
|
|
struct in_ifaddr *
|
|
ifptoia(ifp)
|
|
struct ifnet *ifp;
|
|
{
|
|
register struct in_ifaddr *ia;
|
|
|
|
for (ia = in_ifaddr; ia; ia = ia->ia_next)
|
|
if (ia->ia_ifp == ifp)
|
|
return (ia);
|
|
return ((struct in_ifaddr *)0);
|
|
}
|
|
|
|
/*
|
|
* Send an icmp packet back to the ip level,
|
|
* after supplying a checksum.
|
|
*/
|
|
icmp_send(m, opts)
|
|
register struct mbuf *m;
|
|
struct mbuf *opts;
|
|
{
|
|
register struct ip *ip = mtod(m, struct ip *);
|
|
register int hlen;
|
|
register struct icmp *icp;
|
|
|
|
hlen = ip->ip_hl << 2;
|
|
m->m_data += hlen;
|
|
m->m_len -= hlen;
|
|
icp = mtod(m, struct icmp *);
|
|
icp->icmp_cksum = 0;
|
|
icp->icmp_cksum = in_cksum(m, ip->ip_len - hlen);
|
|
m->m_data -= hlen;
|
|
m->m_len += hlen;
|
|
#ifdef ICMPPRINTFS
|
|
if (icmpprintfs)
|
|
printf("icmp_send dst %x src %x\n", ip->ip_dst, ip->ip_src);
|
|
#endif
|
|
(void) ip_output(m, opts, (struct route *)0, 0);
|
|
}
|
|
|
|
n_time
|
|
iptime()
|
|
{
|
|
struct timeval atv;
|
|
u_long t;
|
|
|
|
microtime(&atv);
|
|
t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000;
|
|
return (htonl(t));
|
|
}
|