921 lines
24 KiB
C
921 lines
24 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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* 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 "opt_mac.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/if_types.h>
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#include <net/route.h>
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#include <netinet/in.h>
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#include <netinet/in_pcb.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/ip_options.h>
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#include <netinet/tcp.h>
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#include <netinet/tcp_var.h>
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#include <netinet/tcpip.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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#ifdef FAST_IPSEC
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#include <netipsec/ipsec.h>
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#include <netipsec/key.h>
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#define IPSEC
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#endif
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#include <machine/in_cksum.h>
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#include <security/mac/mac_framework.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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struct icmpstat icmpstat;
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SYSCTL_STRUCT(_net_inet_icmp, ICMPCTL_STATS, stats, CTLFLAG_RW,
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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, "Reply to ICMP Address Mask Request packets.");
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static u_int icmpmaskfake = 0;
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SYSCTL_UINT(_net_inet_icmp, OID_AUTO, maskfake, CTLFLAG_RW,
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&icmpmaskfake, 0, "Fake reply to ICMP Address Mask Request packets.");
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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, "Ignore ICMP redirects");
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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, "Log ICMP redirects to the console");
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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, "Maximum number of ICMP responses per second");
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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, "Enable rate limiting of ICMP responses");
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static char reply_src[IFNAMSIZ];
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SYSCTL_STRING(_net_inet_icmp, OID_AUTO, reply_src, CTLFLAG_RW,
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&reply_src, IFNAMSIZ, "icmp reply source for non-local packets.");
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static int icmp_rfi = 0;
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SYSCTL_INT(_net_inet_icmp, OID_AUTO, reply_from_interface, CTLFLAG_RW,
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&icmp_rfi, 0, "ICMP reply from incoming interface for "
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"non-local packets");
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static int icmp_quotelen = 8;
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SYSCTL_INT(_net_inet_icmp, OID_AUTO, quotelen, CTLFLAG_RW,
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&icmp_quotelen, 0, "Number of bytes from original packet to "
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"quote in ICMP reply");
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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(struct mbuf *);
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static void icmp_send(struct mbuf *, struct mbuf *);
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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(struct mbuf *n, int type, int code, n_long dest, int mtu)
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{
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register struct ip *oip = mtod(n, struct ip *), *nip;
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register unsigned oiphlen = 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, icmpelen, nlen;
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KASSERT((u_int)type <= ICMP_MAXTYPE, ("%s: illegal ICMP type", __func__));
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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:
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* if the original packet was encrypted.
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* if not the first fragment of message.
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* in response to a multicast or broadcast packet.
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* if the old packet protocol was an ICMP error message.
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*/
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if (n->m_flags & M_DECRYPTED)
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goto freeit;
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if (oip->ip_off & ~(IP_MF|IP_DF))
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goto freeit;
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if (n->m_flags & (M_BCAST|M_MCAST))
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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 >= oiphlen + ICMP_MINLEN &&
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!ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiphlen))->icmp_type)) {
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icmpstat.icps_oldicmp++;
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goto freeit;
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}
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/* Drop if IP header plus 8 bytes is not contignous in first mbuf. */
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if (oiphlen + 8 > n->m_len)
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goto freeit;
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/*
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* Calculate length to quote from original packet and
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* prevent the ICMP mbuf from overflowing.
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* Unfortunatly this is non-trivial since ip_forward()
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* sends us truncated packets.
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*/
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nlen = m_length(n, NULL);
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if (oip->ip_p == IPPROTO_TCP) {
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struct tcphdr *th;
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int tcphlen;
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if (oiphlen + sizeof(struct tcphdr) > n->m_len &&
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n->m_next == NULL)
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goto stdreply;
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if (n->m_len < oiphlen + sizeof(struct tcphdr) &&
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((n = m_pullup(n, oiphlen + sizeof(struct tcphdr))) == NULL))
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goto freeit;
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th = (struct tcphdr *)((caddr_t)oip + oiphlen);
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tcphlen = th->th_off << 2;
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if (tcphlen < sizeof(struct tcphdr))
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goto freeit;
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if (oip->ip_len < oiphlen + tcphlen)
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goto freeit;
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if (oiphlen + tcphlen > n->m_len && n->m_next == NULL)
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goto stdreply;
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if (n->m_len < oiphlen + tcphlen &&
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((n = m_pullup(n, oiphlen + tcphlen)) == NULL))
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goto freeit;
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icmpelen = max(tcphlen, min(icmp_quotelen, oip->ip_len - oiphlen));
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} else
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stdreply: icmpelen = max(8, min(icmp_quotelen, oip->ip_len - oiphlen));
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icmplen = min(oiphlen + icmpelen, nlen);
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if (icmplen < sizeof(struct ip))
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goto freeit;
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if (MHLEN > sizeof(struct ip) + ICMP_MINLEN + icmplen)
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m = m_gethdr(M_DONTWAIT, MT_DATA);
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else
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m = m_getcl(M_DONTWAIT, MT_DATA, M_PKTHDR);
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if (m == NULL)
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goto freeit;
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#ifdef MAC
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mac_create_mbuf_netlayer(n, m);
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#endif
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icmplen = min(icmplen, M_TRAILINGSPACE(m) - sizeof(struct ip) - ICMP_MINLEN);
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m_align(m, ICMP_MINLEN + icmplen);
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m->m_len = ICMP_MINLEN + icmplen;
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icp = mtod(m, struct icmp *);
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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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* just 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 && mtu) {
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icp->icmp_nextmtu = htons(mtu);
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}
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}
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icp->icmp_code = code;
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/*
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* Copy the quotation into ICMP message and
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* convert quoted IP header back to network representation.
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*/
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m_copydata(n, 0, icmplen, (caddr_t)&icp->icmp_ip);
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nip = &icp->icmp_ip;
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nip->ip_len = htons(nip->ip_len);
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nip->ip_off = htons(nip->ip_off);
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/*
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* Set up ICMP message mbuf and copy old IP header (without options
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* in front of ICMP message.
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* If the original mbuf was meant to bypass the firewall, the error
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* reply should bypass as well.
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*/
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m->m_flags |= n->m_flags & M_SKIP_FIREWALL;
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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_v = IPVERSION;
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nip->ip_hl = 5;
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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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/*
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* Process a received ICMP message.
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*/
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void
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icmp_input(struct mbuf *m, int off)
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{
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struct icmp *icp;
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struct in_ifaddr *ia;
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struct ip *ip = mtod(m, struct ip *);
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struct sockaddr_in icmpsrc, icmpdst, icmpgw;
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int hlen = off;
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int icmplen = ip->ip_len;
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int i, code;
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void (*ctlfunc)(int, struct sockaddr *, void *);
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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 (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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#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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/*
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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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/* Initialize */
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bzero(&icmpsrc, sizeof(icmpsrc));
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icmpsrc.sin_len = sizeof(struct sockaddr_in);
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icmpsrc.sin_family = AF_INET;
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bzero(&icmpdst, sizeof(icmpdst));
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icmpdst.sin_len = sizeof(struct sockaddr_in);
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icmpdst.sin_family = AF_INET;
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bzero(&icmpgw, sizeof(icmpgw));
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icmpgw.sin_len = sizeof(struct sockaddr_in);
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icmpgw.sin_family = AF_INET;
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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_SRCFAIL:
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case ICMP_UNREACH_NET_UNKNOWN:
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case ICMP_UNREACH_HOST_UNKNOWN:
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case ICMP_UNREACH_ISOLATED:
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case ICMP_UNREACH_TOSNET:
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case ICMP_UNREACH_TOSHOST:
|
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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_NET;
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break;
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|
|
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case ICMP_UNREACH_NEEDFRAG:
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code = PRC_MSGSIZE;
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break;
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|
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/*
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* RFC 1122, Sections 3.2.2.1 and 4.2.3.9.
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* Treat subcodes 2,3 as immediate RST
|
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*/
|
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case ICMP_UNREACH_PROTOCOL:
|
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case ICMP_UNREACH_PORT:
|
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code = PRC_UNREACH_PORT;
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break;
|
|
|
|
case ICMP_UNREACH_NET_PROHIB:
|
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case ICMP_UNREACH_HOST_PROHIB:
|
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case ICMP_UNREACH_FILTER_PROHIB:
|
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code = PRC_UNREACH_ADMIN_PROHIB;
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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;
|
|
|
|
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;
|
|
|
|
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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* 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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}
|
|
icp->icmp_ip.ip_len = ntohs(icp->icmp_ip.ip_len);
|
|
/* 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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/*
|
|
* XXX if the packet contains [IPv4 AH TCP], we can't make a
|
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* notification to TCP layer.
|
|
*/
|
|
ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput;
|
|
if (ctlfunc)
|
|
(*ctlfunc)(code, (struct sockaddr *)&icmpsrc,
|
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(void *)&icp->icmp_ip);
|
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break;
|
|
|
|
badcode:
|
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icmpstat.icps_badcode++;
|
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break;
|
|
|
|
case ICMP_ECHO:
|
|
if (!icmpbmcastecho
|
|
&& (m->m_flags & (M_MCAST | M_BCAST)) != 0) {
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icmpstat.icps_bmcastecho++;
|
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break;
|
|
}
|
|
icp->icmp_type = ICMP_ECHOREPLY;
|
|
if (badport_bandlim(BANDLIM_ICMP_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_ICMP_TSTAMP) < 0)
|
|
goto freeit;
|
|
else
|
|
goto reflect;
|
|
|
|
case ICMP_MASKREQ:
|
|
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;
|
|
if (icmpmaskfake == 0)
|
|
icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr;
|
|
else
|
|
icp->icmp_mask = icmpmaskfake;
|
|
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));
|
|
}
|
|
/*
|
|
* RFC1812 says we must ignore ICMP redirects if we
|
|
* are acting as router.
|
|
*/
|
|
if (drop_redirect || ipforwarding)
|
|
break;
|
|
if (code > 3)
|
|
goto badcode;
|
|
if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
|
|
icp->icmp_ip.ip_hl < (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);
|
|
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);
|
|
return;
|
|
|
|
freeit:
|
|
m_freem(m);
|
|
}
|
|
|
|
/*
|
|
* Reflect the ip packet back to the source
|
|
*/
|
|
static void
|
|
icmp_reflect(struct mbuf *m)
|
|
{
|
|
struct ip *ip = mtod(m, struct ip *);
|
|
struct ifaddr *ifa;
|
|
struct ifnet *ifn;
|
|
struct in_ifaddr *ia;
|
|
struct in_addr t;
|
|
struct mbuf *opts = 0;
|
|
int optlen = (ip->ip_hl << 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 */
|
|
icmpstat.icps_badaddr++;
|
|
goto done; /* Ip_output() will check for broadcast */
|
|
}
|
|
t = ip->ip_dst;
|
|
ip->ip_dst = ip->ip_src;
|
|
|
|
/*
|
|
* Source selection for ICMP replies:
|
|
*
|
|
* If the incoming packet was addressed directly to one of our
|
|
* own addresses, use dst as the src for the reply.
|
|
*/
|
|
LIST_FOREACH(ia, INADDR_HASH(t.s_addr), ia_hash)
|
|
if (t.s_addr == IA_SIN(ia)->sin_addr.s_addr)
|
|
goto match;
|
|
/*
|
|
* If the incoming packet was addressed to one of our broadcast
|
|
* addresses, use the first non-broadcast address which corresponds
|
|
* to the incoming interface.
|
|
*/
|
|
if (m->m_pkthdr.rcvif != NULL &&
|
|
m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) {
|
|
TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) {
|
|
if (ifa->ifa_addr->sa_family != AF_INET)
|
|
continue;
|
|
ia = ifatoia(ifa);
|
|
if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
|
|
t.s_addr)
|
|
goto match;
|
|
}
|
|
}
|
|
/*
|
|
* If the packet was transiting through us, use the address of
|
|
* the interface the packet came through in. If that interface
|
|
* doesn't have a suitable IP address, the normal selection
|
|
* criteria apply.
|
|
*/
|
|
if (icmp_rfi && m->m_pkthdr.rcvif != NULL) {
|
|
TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) {
|
|
if (ifa->ifa_addr->sa_family != AF_INET)
|
|
continue;
|
|
ia = ifatoia(ifa);
|
|
goto match;
|
|
}
|
|
}
|
|
/*
|
|
* If the incoming packet was not addressed directly to us, use
|
|
* designated interface for icmp replies specified by sysctl
|
|
* net.inet.icmp.reply_src (default not set). Otherwise continue
|
|
* with normal source selection.
|
|
*/
|
|
if (reply_src[0] != '\0' && (ifn = ifunit(reply_src))) {
|
|
TAILQ_FOREACH(ifa, &ifn->if_addrhead, ifa_link) {
|
|
if (ifa->ifa_addr->sa_family != AF_INET)
|
|
continue;
|
|
ia = ifatoia(ifa);
|
|
goto match;
|
|
}
|
|
}
|
|
/*
|
|
* If the packet was transiting through us, use the address of
|
|
* the interface that is the closest to the packet source.
|
|
* When we don't have a route back to the packet source, stop here
|
|
* and drop the packet.
|
|
*/
|
|
ia = ip_rtaddr(ip->ip_dst);
|
|
if (ia == NULL) {
|
|
m_freem(m);
|
|
icmpstat.icps_noroute++;
|
|
goto done;
|
|
}
|
|
match:
|
|
#ifdef MAC
|
|
mac_reflect_mbuf_icmp(m);
|
|
#endif
|
|
t = IA_SIN(ia)->sin_addr;
|
|
ip->ip_src = t;
|
|
ip->ip_ttl = ip_defttl;
|
|
|
|
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(m)) == 0 &&
|
|
(opts = m_gethdr(M_DONTWAIT, MT_DATA))) {
|
|
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_v = IPVERSION;
|
|
ip->ip_hl = 5;
|
|
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_tag_delete_nonpersistent(m);
|
|
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(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;
|
|
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
|
|
(void) ip_output(m, opts, NULL, 0, NULL, NULL);
|
|
}
|
|
|
|
n_time
|
|
iptime(void)
|
|
{
|
|
struct timeval atv;
|
|
u_long t;
|
|
|
|
getmicrotime(&atv);
|
|
t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000;
|
|
return (htonl(t));
|
|
}
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
int
|
|
ip_next_mtu(int mtu, int dir)
|
|
{
|
|
static int mtutab[] = {
|
|
65535, 32000, 17914, 8166, 4352, 2002, 1492, 1280, 1006, 508,
|
|
296, 68, 0
|
|
};
|
|
int i, size;
|
|
|
|
size = (sizeof mtutab) / (sizeof mtutab[0]);
|
|
if (dir >= 0) {
|
|
for (i = 0; i < size; i++)
|
|
if (mtu > mtutab[i])
|
|
return mtutab[i];
|
|
} else {
|
|
for (i = size - 1; i >= 0; i--)
|
|
if (mtu < mtutab[i])
|
|
return mtutab[i];
|
|
if (mtu == mtutab[0])
|
|
return mtutab[0];
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
|
|
/*
|
|
* 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)
|
|
{
|
|
#define N(a) (sizeof (a) / sizeof (a[0]))
|
|
static struct rate {
|
|
const char *type;
|
|
struct timeval lasttime;
|
|
int curpps;
|
|
} rates[BANDLIM_MAX+1] = {
|
|
{ "icmp unreach response" },
|
|
{ "icmp ping response" },
|
|
{ "icmp tstamp response" },
|
|
{ "closed port RST response" },
|
|
{ "open port RST response" }
|
|
};
|
|
|
|
/*
|
|
* Return ok status if feature disabled or argument out of range.
|
|
*/
|
|
if (icmplim > 0 && (u_int) which < N(rates)) {
|
|
struct rate *r = &rates[which];
|
|
int opps = r->curpps;
|
|
|
|
if (!ppsratecheck(&r->lasttime, &r->curpps, icmplim))
|
|
return -1; /* discard packet */
|
|
/*
|
|
* If we've dropped below the threshold after having
|
|
* rate-limited traffic print the message. This preserves
|
|
* the previous behaviour at the expense of added complexity.
|
|
*/
|
|
if (icmplim_output && opps > icmplim)
|
|
printf("Limiting %s from %d to %d packets/sec\n",
|
|
r->type, opps, icmplim);
|
|
}
|
|
return 0; /* okay to send packet */
|
|
#undef N
|
|
}
|