dd1037ee0c
messages send by routers when they deny our traffic, this causes
a timeout when trying to connect to TCP ports/services on a remote
host, which is blocked by routers or firewalls.
rfc1122 (Requirements for Internet Hosts) section 3.2.2.1 actually
requi re that we treat such a message for a TCP session, that we
treat it like if we had recieved a RST.
quote begin.
A Destination Unreachable message that is received MUST be
reported to the transport layer. The transport layer SHOULD
use the information appropriately; for example, see Sections
4.1.3.3, 4.2.3.9, and 4.2.4 below. A transport protocol
that has its own mechanism for notifying the sender that a
port is unreachable (e.g., TCP, which sends RST segments)
MUST nevertheless accept an ICMP Port Unreachable for the
same purpose.
quote end.
I've written a small extension that implement this, it also create
a sysctl "net.inet.tcp.icmp_admin_prohib_like_rst" to control if
this new behaviour is activated.
When it's activated (set to 1) we'll treat a ICMP administratively
prohibited message (icmp type 3 code 9, 10 and 13) for a TCP
sessions, as if we recived a TCP RST, but only if the TCP session
is in SYN_SENT state.
The reason for only reacting when in SYN_SENT state, is that this
will solve the problem, and at the same time minimize the risk of
this being abused.
I suggest that we enable this new behaviour by default, but it
would be a change of current behaviour, so if people prefer to
leave it disabled by default, at least for now, this would be ok
for me, the attached diff actually have the sysctl set to 0 by
default.
PR: 23086
Submitted by: Jesper Skriver <jesper@skriver.dk>
891 lines
22 KiB
C
891 lines
22 KiB
C
/*
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* Copyright (c) 1982, 1986, 1988, 1993
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* The Regents of the University of California. 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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* @(#)ip_icmp.c 8.2 (Berkeley) 1/4/94
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* $FreeBSD$
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*/
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#include "opt_ipsec.h"
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#include <sys/param.h>
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#include <sys/systm.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 <sys/sysctl.h>
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#include <net/if.h>
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#include <net/route.h>
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#define _IP_VHL
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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/ip_var.h>
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#include <netinet/icmp_var.h>
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#ifdef IPSEC
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#include <netinet6/ipsec.h>
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#include <netkey/key.h>
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#endif
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#include "faith.h"
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#if defined(NFAITH) && NFAITH > 0
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#include <net/if_types.h>
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#endif
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#include <machine/in_cksum.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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static struct icmpstat icmpstat;
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SYSCTL_STRUCT(_net_inet_icmp, ICMPCTL_STATS, stats, CTLFLAG_RD,
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&icmpstat, icmpstat, "");
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static int icmpmaskrepl = 0;
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SYSCTL_INT(_net_inet_icmp, ICMPCTL_MASKREPL, maskrepl, CTLFLAG_RW,
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&icmpmaskrepl, 0, "");
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static int drop_redirect = 0;
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SYSCTL_INT(_net_inet_icmp, OID_AUTO, drop_redirect, CTLFLAG_RW,
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&drop_redirect, 0, "");
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static int log_redirect = 0;
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SYSCTL_INT(_net_inet_icmp, OID_AUTO, log_redirect, CTLFLAG_RW,
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&log_redirect, 0, "");
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static int icmplim = 200;
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SYSCTL_INT(_net_inet_icmp, ICMPCTL_ICMPLIM, icmplim, CTLFLAG_RW,
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&icmplim, 0, "");
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static int icmplim_output = 1;
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SYSCTL_INT(_net_inet_icmp, OID_AUTO, icmplim_output, CTLFLAG_RW,
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&icmplim_output, 0, "");
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/*
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* ICMP broadcast echo sysctl
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*/
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static int icmpbmcastecho = 0;
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SYSCTL_INT(_net_inet_icmp, OID_AUTO, bmcastecho, CTLFLAG_RW,
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&icmpbmcastecho, 0, "");
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#ifdef ICMPPRINTFS
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int icmpprintfs = 0;
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#endif
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static void icmp_reflect __P((struct mbuf *));
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static void icmp_send __P((struct mbuf *, struct mbuf *));
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static int ip_next_mtu __P((int, int));
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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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void
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icmp_error(n, type, code, dest, destifp)
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struct mbuf *n;
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int type, code;
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n_long dest;
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struct ifnet *destifp;
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{
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register struct ip *oip = mtod(n, struct ip *), *nip;
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register unsigned oiplen = IP_VHL_HL(oip->ip_vhl) << 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(%p, %x, %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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/* Don't send error in response to a multicast or broadcast packet */
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if (n->m_flags & (M_BCAST|M_MCAST))
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goto freeit;
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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 = min(oiplen + 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.s_addr = dest;
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else {
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icp->icmp_void = 0;
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/*
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* The following assignments assume an overlay with the
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* zeroed icmp_void field.
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*/
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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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} else if (type == ICMP_UNREACH &&
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code == ICMP_UNREACH_NEEDFRAG && destifp) {
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icp->icmp_nextmtu = htons(destifp->if_mtu);
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}
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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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/*
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* Convert fields to network representation.
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*/
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HTONS(nip->ip_len);
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HTONS(nip->ip_off);
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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, sizeof(struct ip));
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nip->ip_len = m->m_len;
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nip->ip_vhl = IP_VHL_BORING;
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nip->ip_p = IPPROTO_ICMP;
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nip->ip_tos = 0;
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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 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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/*
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* Process a received ICMP message.
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*/
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void
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icmp_input(m, off, proto)
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register struct mbuf *m;
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int off, proto;
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{
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int hlen = off;
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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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void (*ctlfunc) __P((int, struct sockaddr *, void *));
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int code;
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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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char buf[4 * sizeof "123"];
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strcpy(buf, inet_ntoa(ip->ip_src));
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printf("icmp_input from %s to %s, len %d\n",
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buf, inet_ntoa(ip->ip_dst), icmplen);
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}
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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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#if defined(NFAITH) && 0 < NFAITH
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if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) {
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/*
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* Deliver very specific ICMP type only.
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*/
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switch (icp->icmp_type) {
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case ICMP_UNREACH:
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case ICMP_TIMXCEED:
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break;
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default:
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goto freeit;
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}
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}
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#endif
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#ifdef ICMPPRINTFS
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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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#ifdef IPSEC
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/* drop it if it does not match the policy */
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/* XXX Is there meaning of check in here ? */
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if (ipsec4_in_reject(m, NULL)) {
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ipsecstat.in_polvio++;
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goto freeit;
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}
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#endif
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/*
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* Message type specific processing.
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*/
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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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switch (code) {
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case ICMP_UNREACH_NET:
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case ICMP_UNREACH_HOST:
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case ICMP_UNREACH_PROTOCOL:
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case ICMP_UNREACH_PORT:
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case ICMP_UNREACH_SRCFAIL:
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code += PRC_UNREACH_NET;
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break;
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case ICMP_UNREACH_NEEDFRAG:
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code = PRC_MSGSIZE;
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break;
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case ICMP_UNREACH_NET_UNKNOWN:
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case ICMP_UNREACH_NET_PROHIB:
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if (icp->icmp_ip.ip_p == IPPROTO_TCP) {
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code = PRC_UNREACH_PORT;
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break;
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}
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case ICMP_UNREACH_TOSNET:
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code = PRC_UNREACH_NET;
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break;
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case ICMP_UNREACH_HOST_UNKNOWN:
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case ICMP_UNREACH_ISOLATED:
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case ICMP_UNREACH_HOST_PROHIB:
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if (icp->icmp_ip.ip_p == IPPROTO_TCP) {
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code = PRC_UNREACH_PORT;
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break;
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}
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case ICMP_UNREACH_TOSHOST:
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code = PRC_UNREACH_HOST;
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break;
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case ICMP_UNREACH_FILTER_PROHIB:
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if (icp->icmp_ip.ip_p == IPPROTO_TCP) {
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code = PRC_UNREACH_PORT;
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break;
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}
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case ICMP_UNREACH_HOST_PRECEDENCE:
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case ICMP_UNREACH_PRECEDENCE_CUTOFF:
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code = PRC_UNREACH_PORT;
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break;
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default:
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goto badcode;
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}
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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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|
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case ICMP_PARAMPROB:
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if (code > 1)
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goto badcode;
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code = PRC_PARAMPROB;
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goto deliver;
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|
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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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IP_VHL_HL(icp->icmp_ip.ip_vhl) < (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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/* Discard ICMP's in response to multicast packets */
|
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if (IN_MULTICAST(ntohl(icp->icmp_ip.ip_dst.s_addr)))
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goto badcode;
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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 1
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|
/*
|
|
* MTU discovery:
|
|
* If we got a needfrag and there is a host route to the
|
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* original destination, and the MTU is not locked, then
|
|
* set the MTU in the route to the suggested new value
|
|
* (if given) and then notify as usual. The ULPs will
|
|
* notice that the MTU has changed and adapt accordingly.
|
|
* If no new MTU was suggested, then we guess a new one
|
|
* less than the current value. If the new MTU is
|
|
* unreasonably small (arbitrarily set at 296), then
|
|
* we reset the MTU to the interface value and enable the
|
|
* lock bit, indicating that we are no longer doing MTU
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|
* discovery.
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|
*/
|
|
if (code == PRC_MSGSIZE) {
|
|
struct rtentry *rt;
|
|
int mtu;
|
|
|
|
rt = rtalloc1((struct sockaddr *)&icmpsrc, 0,
|
|
RTF_CLONING | RTF_PRCLONING);
|
|
if (rt && (rt->rt_flags & RTF_HOST)
|
|
&& !(rt->rt_rmx.rmx_locks & RTV_MTU)) {
|
|
mtu = ntohs(icp->icmp_nextmtu);
|
|
if (!mtu)
|
|
mtu = ip_next_mtu(rt->rt_rmx.rmx_mtu,
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|
1);
|
|
#ifdef DEBUG_MTUDISC
|
|
printf("MTU for %s reduced to %d\n",
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inet_ntoa(icmpsrc.sin_addr), mtu);
|
|
#endif
|
|
if (mtu < 296) {
|
|
/* rt->rt_rmx.rmx_mtu =
|
|
rt->rt_ifp->if_mtu; */
|
|
rt->rt_rmx.rmx_locks |= RTV_MTU;
|
|
} else if (rt->rt_rmx.rmx_mtu > mtu) {
|
|
rt->rt_rmx.rmx_mtu = mtu;
|
|
}
|
|
}
|
|
if (rt)
|
|
RTFREE(rt);
|
|
}
|
|
|
|
#endif
|
|
/*
|
|
* XXX if the packet contains [IPv4 AH TCP], we can't make a
|
|
* notification to TCP layer.
|
|
*/
|
|
ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput;
|
|
if (ctlfunc)
|
|
(*ctlfunc)(code, (struct sockaddr *)&icmpsrc,
|
|
(void *)&icp->icmp_ip);
|
|
break;
|
|
|
|
badcode:
|
|
icmpstat.icps_badcode++;
|
|
break;
|
|
|
|
case ICMP_ECHO:
|
|
if (!icmpbmcastecho
|
|
&& (m->m_flags & (M_MCAST | M_BCAST)) != 0) {
|
|
icmpstat.icps_bmcastecho++;
|
|
break;
|
|
}
|
|
icp->icmp_type = ICMP_ECHOREPLY;
|
|
if (badport_bandlim(BANDLIM_ECHO) < 0)
|
|
goto freeit;
|
|
else
|
|
goto reflect;
|
|
|
|
case ICMP_TSTAMP:
|
|
if (!icmpbmcastecho
|
|
&& (m->m_flags & (M_MCAST | M_BCAST)) != 0) {
|
|
icmpstat.icps_bmcasttstamp++;
|
|
break;
|
|
}
|
|
if (icmplen < ICMP_TSLEN) {
|
|
icmpstat.icps_badlen++;
|
|
break;
|
|
}
|
|
icp->icmp_type = ICMP_TSTAMPREPLY;
|
|
icp->icmp_rtime = iptime();
|
|
icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */
|
|
if (badport_bandlim(BANDLIM_TSTAMP) < 0)
|
|
goto freeit;
|
|
else
|
|
goto reflect;
|
|
|
|
case ICMP_MASKREQ:
|
|
#define satosin(sa) ((struct sockaddr_in *)(sa))
|
|
if (icmpmaskrepl == 0)
|
|
break;
|
|
/*
|
|
* We are not able to respond with all ones broadcast
|
|
* unless we receive it over a point-to-point interface.
|
|
*/
|
|
if (icmplen < ICMP_MASKLEN)
|
|
break;
|
|
switch (ip->ip_dst.s_addr) {
|
|
|
|
case INADDR_BROADCAST:
|
|
case INADDR_ANY:
|
|
icmpdst.sin_addr = ip->ip_src;
|
|
break;
|
|
|
|
default:
|
|
icmpdst.sin_addr = ip->ip_dst;
|
|
}
|
|
ia = (struct in_ifaddr *)ifaof_ifpforaddr(
|
|
(struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif);
|
|
if (ia == 0)
|
|
break;
|
|
if (ia->ia_ifp == 0)
|
|
break;
|
|
icp->icmp_type = ICMP_MASKREPLY;
|
|
icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr;
|
|
if (ip->ip_src.s_addr == 0) {
|
|
if (ia->ia_ifp->if_flags & IFF_BROADCAST)
|
|
ip->ip_src = satosin(&ia->ia_broadaddr)->sin_addr;
|
|
else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT)
|
|
ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr;
|
|
}
|
|
reflect:
|
|
ip->ip_len += hlen; /* since ip_input deducts this */
|
|
icmpstat.icps_reflect++;
|
|
icmpstat.icps_outhist[icp->icmp_type]++;
|
|
icmp_reflect(m);
|
|
return;
|
|
|
|
case ICMP_REDIRECT:
|
|
if (log_redirect) {
|
|
u_long src, dst, gw;
|
|
|
|
src = ntohl(ip->ip_src.s_addr);
|
|
dst = ntohl(icp->icmp_ip.ip_dst.s_addr);
|
|
gw = ntohl(icp->icmp_gwaddr.s_addr);
|
|
printf("icmp redirect from %d.%d.%d.%d: "
|
|
"%d.%d.%d.%d => %d.%d.%d.%d\n",
|
|
(int)(src >> 24), (int)((src >> 16) & 0xff),
|
|
(int)((src >> 8) & 0xff), (int)(src & 0xff),
|
|
(int)(dst >> 24), (int)((dst >> 16) & 0xff),
|
|
(int)((dst >> 8) & 0xff), (int)(dst & 0xff),
|
|
(int)(gw >> 24), (int)((gw >> 16) & 0xff),
|
|
(int)((gw >> 8) & 0xff), (int)(gw & 0xff));
|
|
}
|
|
if (drop_redirect)
|
|
break;
|
|
if (code > 3)
|
|
goto badcode;
|
|
if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
|
|
IP_VHL_HL(icp->icmp_ip.ip_vhl) < (sizeof(struct ip) >> 2)) {
|
|
icmpstat.icps_badlen++;
|
|
break;
|
|
}
|
|
/*
|
|
* Short circuit routing redirects to force
|
|
* immediate change in the kernel's routing
|
|
* tables. The message is also handed to anyone
|
|
* listening on a raw socket (e.g. the routing
|
|
* daemon for use in updating its tables).
|
|
*/
|
|
icmpgw.sin_addr = ip->ip_src;
|
|
icmpdst.sin_addr = icp->icmp_gwaddr;
|
|
#ifdef ICMPPRINTFS
|
|
if (icmpprintfs) {
|
|
char buf[4 * sizeof "123"];
|
|
strcpy(buf, inet_ntoa(icp->icmp_ip.ip_dst));
|
|
|
|
printf("redirect dst %s to %s\n",
|
|
buf, inet_ntoa(icp->icmp_gwaddr));
|
|
}
|
|
#endif
|
|
icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
|
|
rtredirect((struct sockaddr *)&icmpsrc,
|
|
(struct sockaddr *)&icmpdst,
|
|
(struct sockaddr *)0, RTF_GATEWAY | RTF_HOST,
|
|
(struct sockaddr *)&icmpgw, (struct rtentry **)0);
|
|
pfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&icmpsrc);
|
|
#ifdef IPSEC
|
|
key_sa_routechange((struct sockaddr *)&icmpsrc);
|
|
#endif
|
|
break;
|
|
|
|
/*
|
|
* No kernel processing for the following;
|
|
* just fall through to send to raw listener.
|
|
*/
|
|
case ICMP_ECHOREPLY:
|
|
case ICMP_ROUTERADVERT:
|
|
case ICMP_ROUTERSOLICIT:
|
|
case ICMP_TSTAMPREPLY:
|
|
case ICMP_IREQREPLY:
|
|
case ICMP_MASKREPLY:
|
|
default:
|
|
break;
|
|
}
|
|
|
|
raw:
|
|
rip_input(m, off, proto);
|
|
return;
|
|
|
|
freeit:
|
|
m_freem(m);
|
|
}
|
|
|
|
/*
|
|
* Reflect the ip packet back to the source
|
|
*/
|
|
static void
|
|
icmp_reflect(m)
|
|
struct mbuf *m;
|
|
{
|
|
register struct ip *ip = mtod(m, struct ip *);
|
|
register struct in_ifaddr *ia;
|
|
struct in_addr t;
|
|
struct mbuf *opts = 0;
|
|
int optlen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip);
|
|
|
|
if (!in_canforward(ip->ip_src) &&
|
|
((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) !=
|
|
(IN_LOOPBACKNET << IN_CLASSA_NSHIFT))) {
|
|
m_freem(m); /* Bad return address */
|
|
goto done; /* Ip_output() will check for broadcast */
|
|
}
|
|
t = ip->ip_dst;
|
|
ip->ip_dst = ip->ip_src;
|
|
/*
|
|
* If the incoming packet was addressed directly to us,
|
|
* use dst as the src for the reply. Otherwise (broadcast
|
|
* or anonymous), use the address which corresponds
|
|
* to the incoming interface.
|
|
*/
|
|
for (ia = in_ifaddrhead.tqh_first; ia; ia = ia->ia_link.tqe_next) {
|
|
if (t.s_addr == IA_SIN(ia)->sin_addr.s_addr)
|
|
break;
|
|
if (ia->ia_ifp && (ia->ia_ifp->if_flags & IFF_BROADCAST) &&
|
|
t.s_addr == satosin(&ia->ia_broadaddr)->sin_addr.s_addr)
|
|
break;
|
|
}
|
|
icmpdst.sin_addr = t;
|
|
if ((ia == (struct in_ifaddr *)0) && m->m_pkthdr.rcvif)
|
|
ia = (struct in_ifaddr *)ifaof_ifpforaddr(
|
|
(struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif);
|
|
/*
|
|
* The following happens if the packet was not addressed to us,
|
|
* and was received on an interface with no IP address.
|
|
*/
|
|
if (ia == (struct in_ifaddr *)0)
|
|
ia = in_ifaddrhead.tqh_first;
|
|
t = IA_SIN(ia)->sin_addr;
|
|
ip->ip_src = t;
|
|
ip->ip_ttl = MAXTTL;
|
|
|
|
if (optlen > 0) {
|
|
register u_char *cp;
|
|
int opt, cnt;
|
|
u_int len;
|
|
|
|
/*
|
|
* Retrieve any source routing from the incoming packet;
|
|
* add on any record-route or timestamp options.
|
|
*/
|
|
cp = (u_char *) (ip + 1);
|
|
if ((opts = ip_srcroute()) == 0 &&
|
|
(opts = m_gethdr(M_DONTWAIT, MT_HEADER))) {
|
|
opts->m_len = sizeof(struct in_addr);
|
|
mtod(opts, struct in_addr *)->s_addr = 0;
|
|
}
|
|
if (opts) {
|
|
#ifdef ICMPPRINTFS
|
|
if (icmpprintfs)
|
|
printf("icmp_reflect optlen %d rt %d => ",
|
|
optlen, opts->m_len);
|
|
#endif
|
|
for (cnt = optlen; cnt > 0; cnt -= len, cp += len) {
|
|
opt = cp[IPOPT_OPTVAL];
|
|
if (opt == IPOPT_EOL)
|
|
break;
|
|
if (opt == IPOPT_NOP)
|
|
len = 1;
|
|
else {
|
|
if (cnt < IPOPT_OLEN + sizeof(*cp))
|
|
break;
|
|
len = cp[IPOPT_OLEN];
|
|
if (len < IPOPT_OLEN + sizeof(*cp) ||
|
|
len > cnt)
|
|
break;
|
|
}
|
|
/*
|
|
* Should check for overflow, but it "can't happen"
|
|
*/
|
|
if (opt == IPOPT_RR || opt == IPOPT_TS ||
|
|
opt == IPOPT_SECURITY) {
|
|
bcopy((caddr_t)cp,
|
|
mtod(opts, caddr_t) + opts->m_len, len);
|
|
opts->m_len += len;
|
|
}
|
|
}
|
|
/* Terminate & pad, if necessary */
|
|
cnt = opts->m_len % 4;
|
|
if (cnt) {
|
|
for (; cnt < 4; cnt++) {
|
|
*(mtod(opts, caddr_t) + opts->m_len) =
|
|
IPOPT_EOL;
|
|
opts->m_len++;
|
|
}
|
|
}
|
|
#ifdef ICMPPRINTFS
|
|
if (icmpprintfs)
|
|
printf("%d\n", opts->m_len);
|
|
#endif
|
|
}
|
|
/*
|
|
* Now strip out original options by copying rest of first
|
|
* mbuf's data back, and adjust the IP length.
|
|
*/
|
|
ip->ip_len -= optlen;
|
|
ip->ip_vhl = IP_VHL_BORING;
|
|
m->m_len -= optlen;
|
|
if (m->m_flags & M_PKTHDR)
|
|
m->m_pkthdr.len -= optlen;
|
|
optlen += sizeof(struct ip);
|
|
bcopy((caddr_t)ip + optlen, (caddr_t)(ip + 1),
|
|
(unsigned)(m->m_len - sizeof(struct ip)));
|
|
}
|
|
m->m_flags &= ~(M_BCAST|M_MCAST);
|
|
icmp_send(m, opts);
|
|
done:
|
|
if (opts)
|
|
(void)m_free(opts);
|
|
}
|
|
|
|
/*
|
|
* Send an icmp packet back to the ip level,
|
|
* after supplying a checksum.
|
|
*/
|
|
static void
|
|
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;
|
|
struct route ro;
|
|
|
|
hlen = IP_VHL_HL(ip->ip_vhl) << 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;
|
|
m->m_pkthdr.rcvif = (struct ifnet *)0;
|
|
#ifdef ICMPPRINTFS
|
|
if (icmpprintfs) {
|
|
char buf[4 * sizeof "123"];
|
|
strcpy(buf, inet_ntoa(ip->ip_dst));
|
|
printf("icmp_send dst %s src %s\n",
|
|
buf, inet_ntoa(ip->ip_src));
|
|
}
|
|
#endif
|
|
bzero(&ro, sizeof ro);
|
|
(void) ip_output(m, opts, &ro, 0, NULL);
|
|
if (ro.ro_rt)
|
|
RTFREE(ro.ro_rt);
|
|
}
|
|
|
|
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));
|
|
}
|
|
|
|
#if 1
|
|
/*
|
|
* Return the next larger or smaller MTU plateau (table from RFC 1191)
|
|
* given current value MTU. If DIR is less than zero, a larger plateau
|
|
* is returned; otherwise, a smaller value is returned.
|
|
*/
|
|
static int
|
|
ip_next_mtu(mtu, dir)
|
|
int mtu;
|
|
int dir;
|
|
{
|
|
static int mtutab[] = {
|
|
65535, 32000, 17914, 8166, 4352, 2002, 1492, 1006, 508, 296,
|
|
68, 0
|
|
};
|
|
int i;
|
|
|
|
for (i = 0; i < (sizeof mtutab) / (sizeof mtutab[0]); i++) {
|
|
if (mtu >= mtutab[i])
|
|
break;
|
|
}
|
|
|
|
if (dir < 0) {
|
|
if (i == 0) {
|
|
return 0;
|
|
} else {
|
|
return mtutab[i - 1];
|
|
}
|
|
} else {
|
|
if (mtutab[i] == 0) {
|
|
return 0;
|
|
} else if(mtu > mtutab[i]) {
|
|
return mtutab[i];
|
|
} else {
|
|
return mtutab[i + 1];
|
|
}
|
|
}
|
|
}
|
|
#endif
|
|
|
|
|
|
/*
|
|
* badport_bandlim() - check for ICMP bandwidth limit
|
|
*
|
|
* Return 0 if it is ok to send an ICMP error response, -1 if we have
|
|
* hit our bandwidth limit and it is not ok.
|
|
*
|
|
* If icmplim is <= 0, the feature is disabled and 0 is returned.
|
|
*
|
|
* For now we separate the TCP and UDP subsystems w/ different 'which'
|
|
* values. We may eventually remove this separation (and simplify the
|
|
* code further).
|
|
*
|
|
* Note that the printing of the error message is delayed so we can
|
|
* properly print the icmp error rate that the system was trying to do
|
|
* (i.e. 22000/100 pps, etc...). This can cause long delays in printing
|
|
* the 'final' error, but it doesn't make sense to solve the printing
|
|
* delay with more complex code.
|
|
*/
|
|
|
|
int
|
|
badport_bandlim(int which)
|
|
{
|
|
static int lticks[BANDLIM_MAX + 1];
|
|
static int lpackets[BANDLIM_MAX + 1];
|
|
int dticks;
|
|
const char *bandlimittype[] = {
|
|
"Limiting icmp unreach response",
|
|
"Limiting closed port RST response",
|
|
"Limiting open port RST response",
|
|
"Limiting icmp ping response",
|
|
"Limiting icmp tstamp response"
|
|
};
|
|
|
|
/*
|
|
* Return ok status if feature disabled or argument out of
|
|
* ranage.
|
|
*/
|
|
|
|
if (icmplim <= 0 || which > BANDLIM_MAX || which < 0)
|
|
return(0);
|
|
dticks = ticks - lticks[which];
|
|
|
|
/*
|
|
* reset stats when cumulative dt exceeds one second.
|
|
*/
|
|
|
|
if ((unsigned int)dticks > hz) {
|
|
if (lpackets[which] > icmplim && icmplim_output) {
|
|
printf("%s from %d to %d packets per second\n",
|
|
bandlimittype[which],
|
|
lpackets[which],
|
|
icmplim
|
|
);
|
|
}
|
|
lticks[which] = ticks;
|
|
lpackets[which] = 0;
|
|
}
|
|
|
|
/*
|
|
* bump packet count
|
|
*/
|
|
|
|
if (++lpackets[which] > icmplim) {
|
|
return(-1);
|
|
}
|
|
return(0);
|
|
}
|
|
|