| 1 | /* $Id: ip_icmp.c 98103 2023-01-17 14:15:46Z vboxsync $ */
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| 2 | /** @file
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| 3 | * NAT - IP/ICMP handling.
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| 4 | */
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| 5 |
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| 6 | /*
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| 7 | * Copyright (C) 2006-2023 Oracle and/or its affiliates.
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| 8 | *
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| 9 | * This file is part of VirtualBox base platform packages, as
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| 10 | * available from https://www.virtualbox.org.
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| 11 | *
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| 12 | * This program is free software; you can redistribute it and/or
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| 13 | * modify it under the terms of the GNU General Public License
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| 14 | * as published by the Free Software Foundation, in version 3 of the
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| 15 | * License.
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| 16 | *
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| 17 | * This program is distributed in the hope that it will be useful, but
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| 18 | * WITHOUT ANY WARRANTY; without even the implied warranty of
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| 19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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| 20 | * General Public License for more details.
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| 21 | *
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| 22 | * You should have received a copy of the GNU General Public License
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| 23 | * along with this program; if not, see <https://www.gnu.org/licenses>.
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| 24 | *
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| 25 | * SPDX-License-Identifier: GPL-3.0-only
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| 26 | */
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| 27 |
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| 28 | /*
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| 29 | * This code is based on:
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| 30 | *
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| 31 | * Copyright (c) 1982, 1986, 1988, 1993
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| 32 | * The Regents of the University of California. All rights reserved.
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| 33 | *
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| 34 | * Redistribution and use in source and binary forms, with or without
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| 35 | * modification, are permitted provided that the following conditions
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| 36 | * are met:
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| 37 | * 1. Redistributions of source code must retain the above copyright
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| 38 | * notice, this list of conditions and the following disclaimer.
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| 39 | * 2. Redistributions in binary form must reproduce the above copyright
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| 40 | * notice, this list of conditions and the following disclaimer in the
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| 41 | * documentation and/or other materials provided with the distribution.
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| 42 | * 3. Neither the name of the University nor the names of its contributors
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| 43 | * may be used to endorse or promote products derived from this software
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| 44 | * without specific prior written permission.
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| 45 | *
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| 46 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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| 47 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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| 48 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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| 49 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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| 50 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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| 51 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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| 52 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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| 53 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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| 54 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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| 55 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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| 56 | * SUCH DAMAGE.
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| 57 | *
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| 58 | * @(#)ip_icmp.c 8.2 (Berkeley) 1/4/94
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| 59 | * ip_icmp.c,v 1.7 1995/05/30 08:09:42 rgrimes Exp
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| 60 | */
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| 61 |
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| 62 | #include "slirp.h"
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| 63 | #include "ip_icmp.h"
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| 64 |
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| 65 | #ifdef VBOX_RAWSOCK_DEBUG_HELPER
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| 66 | int getrawsock(int type);
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| 67 | #endif
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| 68 |
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| 69 |
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| 70 | /* The message sent when emulating PING */
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| 71 | /* Be nice and tell them it's just a psuedo-ping packet */
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| 72 | #if 0 /* unused */
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| 73 | static const char icmp_ping_msg[] = "This is a psuedo-PING packet used by Slirp to emulate ICMP ECHO-REQUEST packets.\n";
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| 74 | #endif
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| 75 |
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| 76 | /* list of actions for icmp_error() on RX of an icmp message */
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| 77 | static const int icmp_flush[19] =
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| 78 | {
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| 79 | /* ECHO REPLY (0) */ 0,
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| 80 | 1,
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| 81 | 1,
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| 82 | /* DEST UNREACH (3) */ 1,
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| 83 | /* SOURCE QUENCH (4)*/ 1,
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| 84 | /* REDIRECT (5) */ 1,
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| 85 | 1,
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| 86 | 1,
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| 87 | /* ECHO (8) */ 0,
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| 88 | /* ROUTERADVERT (9) */ 1,
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| 89 | /* ROUTERSOLICIT (10) */ 1,
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| 90 | /* TIME EXCEEDED (11) */ 1,
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| 91 | /* PARAMETER PROBLEM (12) */ 1,
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| 92 | /* TIMESTAMP (13) */ 0,
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| 93 | /* TIMESTAMP REPLY (14) */ 0,
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| 94 | /* INFO (15) */ 0,
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| 95 | /* INFO REPLY (16) */ 0,
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| 96 | /* ADDR MASK (17) */ 0,
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| 97 | /* ADDR MASK REPLY (18) */ 0
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| 98 | };
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| 99 |
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| 100 |
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| 101 | int
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| 102 | icmp_init(PNATState pData, int iIcmpCacheLimit)
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| 103 | {
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| 104 | pData->icmp_socket.so_type = IPPROTO_ICMP;
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| 105 | pData->icmp_socket.so_state = SS_ISFCONNECTED;
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| 106 |
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| 107 | #ifndef RT_OS_WINDOWS
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| 108 | TAILQ_INIT(&pData->icmp_msg_head);
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| 109 |
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| 110 | if (iIcmpCacheLimit < 0)
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| 111 | {
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| 112 | LogRel(("NAT: iIcmpCacheLimit is invalid %d, will be alter to default value 100\n", iIcmpCacheLimit));
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| 113 | iIcmpCacheLimit = 100;
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| 114 | }
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| 115 | pData->iIcmpCacheLimit = iIcmpCacheLimit;
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| 116 | # ifndef RT_OS_DARWIN
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| 117 | pData->icmp_socket.s = socket(PF_INET, SOCK_RAW, IPPROTO_ICMP);
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| 118 | # else /* !RT_OS_DARWIN */
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| 119 | pData->icmp_socket.s = socket(AF_INET, SOCK_DGRAM, IPPROTO_ICMP);
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| 120 | # endif /* RT_OS_DARWIN */
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| 121 | if (pData->icmp_socket.s == -1)
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| 122 | {
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| 123 | int rc = RTErrConvertFromErrno(errno);
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| 124 | # if defined(RT_OS_DARWIN) || !defined(VBOX_RAWSOCK_DEBUG_HELPER)
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| 125 | LogRel(("NAT: ICMP/ping not available (could not open ICMP socket, error %Rrc)\n", rc));
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| 126 | return 1;
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| 127 | # else
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| 128 | /* try to get it from privileged helper */
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| 129 | LogRel(("NAT: ICMP/ping raw socket error %Rrc, asking helper...\n", rc));
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| 130 | pData->icmp_socket.s = getrawsock(AF_INET);
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| 131 | if (pData->icmp_socket.s == -1)
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| 132 | {
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| 133 | LogRel(("NAT: ICMP/ping not available\n"));
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| 134 | return 1;
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| 135 | }
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| 136 | # endif /* !RT_OS_DARWIN && VBOX_RAWSOCK_DEBUG_HELPER */
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| 137 | }
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| 138 | fd_nonblock(pData->icmp_socket.s);
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| 139 | NSOCK_INC();
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| 140 |
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| 141 | #else /* RT_OS_WINDOWS */
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| 142 | RT_NOREF(iIcmpCacheLimit);
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| 143 |
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| 144 | if (icmpwin_init(pData) != 0)
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| 145 | return 1;
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| 146 | #endif /* RT_OS_WINDOWS */
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| 147 |
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| 148 | return 0;
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| 149 | }
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| 150 |
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| 151 | /**
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| 152 | * Cleans ICMP cache.
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| 153 | */
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| 154 | void
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| 155 | icmp_finit(PNATState pData)
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| 156 | {
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| 157 | #ifdef RT_OS_WINDOWS
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| 158 | icmpwin_finit(pData);
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| 159 | #else
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| 160 | while (!TAILQ_EMPTY(&pData->icmp_msg_head))
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| 161 | {
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| 162 | struct icmp_msg *icm = TAILQ_FIRST(&pData->icmp_msg_head);
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| 163 | icmp_msg_delete(pData, icm);
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| 164 | }
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| 165 | closesocket(pData->icmp_socket.s);
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| 166 | #endif
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| 167 | }
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| 168 |
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| 169 |
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| 170 | #if !defined(RT_OS_WINDOWS)
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| 171 | static struct icmp_msg *
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| 172 | icmp_msg_alloc(PNATState pData)
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| 173 | {
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| 174 | struct icmp_msg *icm;
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| 175 |
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| 176 | #ifdef DEBUG
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| 177 | {
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| 178 | int iTally = 0;
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| 179 | TAILQ_FOREACH(icm, &pData->icmp_msg_head, im_queue)
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| 180 | ++iTally;
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| 181 | Assert(pData->cIcmpCacheSize == iTally);
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| 182 | }
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| 183 | #endif
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| 184 |
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| 185 | if (pData->cIcmpCacheSize >= pData->iIcmpCacheLimit)
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| 186 | {
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| 187 | int cTargetCacheSize = pData->iIcmpCacheLimit/2;
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| 188 |
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| 189 | while (pData->cIcmpCacheSize > cTargetCacheSize)
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| 190 | {
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| 191 | icm = TAILQ_FIRST(&pData->icmp_msg_head);
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| 192 | icmp_msg_delete(pData, icm);
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| 193 | }
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| 194 | }
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| 195 |
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| 196 | icm = RTMemAlloc(sizeof(struct icmp_msg));
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| 197 | if (RT_UNLIKELY(icm == NULL))
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| 198 | return NULL;
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| 199 |
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| 200 | TAILQ_INSERT_TAIL(&pData->icmp_msg_head, icm, im_queue);
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| 201 | pData->cIcmpCacheSize++;
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| 202 |
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| 203 | return icm;
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| 204 | }
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| 205 |
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| 206 |
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| 207 | static void
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| 208 | icmp_attach(PNATState pData, struct mbuf *m)
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| 209 | {
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| 210 | struct icmp_msg *icm;
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| 211 |
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| 212 | #ifdef DEBUG
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| 213 | {
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| 214 | /* only used for ping */
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| 215 | struct ip *ip = mtod(m, struct ip *);
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| 216 | Assert(ip->ip_p == IPPROTO_ICMP);
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| 217 | }
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| 218 | #endif
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| 219 |
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| 220 | icm = icmp_msg_alloc(pData);
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| 221 | if (RT_UNLIKELY(icm == NULL))
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| 222 | return;
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| 223 |
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| 224 | icm->im_so = &pData->icmp_socket;
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| 225 | icm->im_m = m;
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| 226 | }
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| 227 |
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| 228 |
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| 229 | void
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| 230 | icmp_msg_delete(PNATState pData, struct icmp_msg *icm)
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| 231 | {
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| 232 | if (RT_UNLIKELY(icm == NULL))
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| 233 | return;
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| 234 |
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| 235 | #ifdef DEBUG
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| 236 | {
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| 237 | struct icmp_msg *existing;
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| 238 | int iTally = 0;
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| 239 |
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| 240 | TAILQ_FOREACH(existing, &pData->icmp_msg_head, im_queue)
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| 241 | ++iTally;
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| 242 | Assert(pData->cIcmpCacheSize == iTally);
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| 243 |
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| 244 | Assert(pData->cIcmpCacheSize > 0);
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| 245 | TAILQ_FOREACH(existing, &pData->icmp_msg_head, im_queue)
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| 246 | {
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| 247 | if (existing == icm)
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| 248 | break;
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| 249 | }
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| 250 | Assert(existing != NULL);
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| 251 | }
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| 252 | #endif
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| 253 |
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| 254 | TAILQ_REMOVE(&pData->icmp_msg_head, icm, im_queue);
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| 255 | pData->cIcmpCacheSize--;
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| 256 |
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| 257 | icm->im_so->so_m = NULL;
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| 258 | if (icm->im_m != NULL)
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| 259 | m_freem(pData, icm->im_m);
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| 260 |
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| 261 | RTMemFree(icm);
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| 262 | }
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| 263 |
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| 264 |
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| 265 | /*
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| 266 | * ip here is ip header + 64bytes readed from ICMP packet
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| 267 | */
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| 268 | struct icmp_msg *
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| 269 | icmp_find_original_mbuf(PNATState pData, struct ip *ip)
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| 270 | {
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| 271 | struct mbuf *m0;
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| 272 | struct ip *ip0;
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| 273 | struct icmp *icp, *icp0;
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| 274 | struct icmp_msg *icm = NULL;
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| 275 | int found = 0;
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| 276 | struct udphdr *udp;
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| 277 | struct tcphdr *tcp;
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| 278 | struct socket *head_socket = NULL;
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| 279 | struct socket *last_socket = NULL;
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| 280 | struct socket *so = NULL;
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| 281 | struct in_addr faddr;
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| 282 | u_short lport, fport;
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| 283 |
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| 284 | faddr.s_addr = ~0;
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| 285 |
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| 286 | lport = ~0;
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| 287 | fport = ~0;
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| 288 |
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| 289 |
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| 290 | LogFlowFunc(("ENTER: ip->ip_p:%d\n", ip->ip_p));
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| 291 | switch (ip->ip_p)
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| 292 | {
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| 293 | case IPPROTO_ICMP:
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| 294 | icp = (struct icmp *)((char *)ip + (ip->ip_hl << 2));
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| 295 | TAILQ_FOREACH(icm, &pData->icmp_msg_head, im_queue)
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| 296 | {
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| 297 | m0 = icm->im_m;
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| 298 | ip0 = mtod(m0, struct ip *);
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| 299 | if (ip0->ip_p != IPPROTO_ICMP)
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| 300 | {
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| 301 | /* try next item */
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| 302 | continue;
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| 303 | }
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| 304 | icp0 = (struct icmp *)((char *)ip0 + (ip0->ip_hl << 2));
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| 305 | /*
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| 306 | * IP could pointer to ICMP_REPLY datagram (1)
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| 307 | * or pointer IP header in ICMP payload in case of
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| 308 | * ICMP_TIMXCEED or ICMP_UNREACH (2)
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| 309 | *
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| 310 | * if (1) and then ICMP (type should be ICMP_ECHOREPLY) and we need check that
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| 311 | * IP.IP_SRC == IP0.IP_DST received datagramm comes from destination.
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| 312 | *
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| 313 | * if (2) then check that payload ICMP has got type ICMP_ECHO and
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| 314 | * IP.IP_DST == IP0.IP_DST destination of returned datagram is the same as
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| 315 | * one was sent.
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| 316 | */
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| 317 | if ( ( (icp->icmp_type != ICMP_ECHO && ip->ip_src.s_addr == ip0->ip_dst.s_addr)
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| 318 | || (icp->icmp_type == ICMP_ECHO && ip->ip_dst.s_addr == ip0->ip_dst.s_addr))
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| 319 | && icp->icmp_id == icp0->icmp_id
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| 320 | && icp->icmp_seq == icp0->icmp_seq)
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| 321 | {
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| 322 | found = 1;
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| 323 | Log(("Have found %R[natsock]\n", icm->im_so));
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| 324 | break;
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| 325 | }
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| 326 | Log(("Have found nothing\n"));
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| 327 | }
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| 328 | break;
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| 329 |
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| 330 | /*
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| 331 | * for TCP and UDP logic little bit reverted, we try to find the HOST socket
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| 332 | * from which the IP package has been sent.
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| 333 | */
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| 334 | case IPPROTO_UDP:
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| 335 | head_socket = &udb;
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| 336 | udp = (struct udphdr *)((char *)ip + (ip->ip_hl << 2));
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| 337 | faddr.s_addr = ip->ip_dst.s_addr;
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| 338 | fport = udp->uh_dport;
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| 339 | lport = udp->uh_sport;
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| 340 | last_socket = udp_last_so;
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| 341 | RT_FALL_THRU();
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| 342 |
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| 343 | case IPPROTO_TCP:
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| 344 | if (head_socket == NULL)
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| 345 | {
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| 346 | tcp = (struct tcphdr *)((char *)ip + (ip->ip_hl << 2));
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| 347 | head_socket = &tcb; /* head_socket could be initialized with udb*/
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| 348 | faddr.s_addr = ip->ip_dst.s_addr;
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| 349 | fport = tcp->th_dport;
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| 350 | lport = tcp->th_sport;
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| 351 | last_socket = tcp_last_so;
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| 352 | }
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| 353 | /* check last socket first */
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| 354 | if ( last_socket->so_faddr.s_addr == faddr.s_addr
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| 355 | && last_socket->so_fport == fport
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| 356 | && last_socket->so_hlport == lport)
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| 357 | {
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| 358 | found = 1;
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| 359 | so = last_socket;
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| 360 | break;
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| 361 | }
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| 362 | for (so = head_socket->so_prev; so != head_socket; so = so->so_prev)
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| 363 | {
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| 364 | /* Should be replaced by hash here */
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| 365 | Log(("trying:%R[natsock] against %RTnaipv4:%d lport=%d hlport=%d\n",
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| 366 | so, faddr.s_addr, ntohs(fport), ntohs(lport), ntohs(so->so_hlport)));
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| 367 | if ( so->so_faddr.s_addr == faddr.s_addr
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| 368 | && so->so_fport == fport
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| 369 | && so->so_hlport == lport)
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| 370 | {
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| 371 | found = 1;
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| 372 | break;
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| 373 | }
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| 374 | }
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| 375 | break;
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| 376 |
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| 377 | default:
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| 378 | Log(("NAT:ICMP: unsupported protocol(%d)\n", ip->ip_p));
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| 379 | }
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| 380 |
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| 381 | #ifdef DEBUG
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| 382 | if (found)
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| 383 | Assert((icm != NULL) ^ (so != NULL));
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| 384 | #endif
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| 385 |
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| 386 | if (found && icm == NULL)
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| 387 | {
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| 388 | /*
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| 389 | * XXX: Implies this is not a pong, found socket. This is, of
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| 390 | * course, wasteful since the caller will delete icmp_msg
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| 391 | * immediately after processing, so there's not much reason to
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| 392 | * clutter up the queue with it.
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| 393 | */
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| 394 | AssertReturn(so != NULL, NULL);
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| 395 |
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| 396 | /*
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| 397 | * XXX: FIXME: If the very first send(2) fails, the socket is
|
|---|
| 398 | * still in SS_NOFDREF and so we will not report this too.
|
|---|
| 399 | */
|
|---|
| 400 | if (so->so_state == SS_NOFDREF)
|
|---|
| 401 | {
|
|---|
| 402 | /* socket is shutting down we've already sent ICMP on it. */
|
|---|
| 403 | Log(("NAT:ICMP: disconnected %R[natsock]\n", so));
|
|---|
| 404 | LogFlowFunc(("LEAVE: icm:NULL\n"));
|
|---|
| 405 | return NULL;
|
|---|
| 406 | }
|
|---|
| 407 |
|
|---|
| 408 | if (so->so_m == NULL)
|
|---|
| 409 | {
|
|---|
| 410 | Log(("NAT:ICMP: no saved mbuf for %R[natsock]\n", so));
|
|---|
| 411 | LogFlowFunc(("LEAVE: icm:NULL\n"));
|
|---|
| 412 | return NULL;
|
|---|
| 413 | }
|
|---|
| 414 |
|
|---|
| 415 | icm = icmp_msg_alloc(pData);
|
|---|
| 416 | if (RT_UNLIKELY(icm == NULL))
|
|---|
| 417 | {
|
|---|
| 418 | LogFlowFunc(("LEAVE: icm:NULL\n"));
|
|---|
| 419 | return NULL;
|
|---|
| 420 | }
|
|---|
| 421 |
|
|---|
| 422 | Log(("NAT:ICMP: for %R[natsock]\n", so));
|
|---|
| 423 | icm->im_so = so;
|
|---|
| 424 | icm->im_m = so->so_m;
|
|---|
| 425 | }
|
|---|
| 426 | LogFlowFunc(("LEAVE: icm:%p\n", icm));
|
|---|
| 427 | return icm;
|
|---|
| 428 | }
|
|---|
| 429 | #endif /* !RT_OS_WINDOWS */
|
|---|
| 430 |
|
|---|
| 431 |
|
|---|
| 432 | /*
|
|---|
| 433 | * Process a received ICMP message.
|
|---|
| 434 | */
|
|---|
| 435 | void
|
|---|
| 436 | icmp_input(PNATState pData, struct mbuf *m, int hlen)
|
|---|
| 437 | {
|
|---|
| 438 | register struct ip *ip = mtod(m, struct ip *);
|
|---|
| 439 | int icmplen = ip->ip_len;
|
|---|
| 440 | uint8_t icmp_type;
|
|---|
| 441 | void *icp_buf = NULL;
|
|---|
| 442 | uint32_t dst;
|
|---|
| 443 |
|
|---|
| 444 | /* int code; */
|
|---|
| 445 |
|
|---|
| 446 | LogFlowFunc(("ENTER: m = %p, m_len = %d\n", m, m ? m->m_len : 0));
|
|---|
| 447 |
|
|---|
| 448 | icmpstat.icps_received++;
|
|---|
| 449 |
|
|---|
| 450 | /*
|
|---|
| 451 | * Locate icmp structure in mbuf, and check
|
|---|
| 452 | * that its not corrupted and of at least minimum length.
|
|---|
| 453 | */
|
|---|
| 454 | if (icmplen < ICMP_MINLEN)
|
|---|
| 455 | {
|
|---|
| 456 | /* min 8 bytes payload */
|
|---|
| 457 | icmpstat.icps_tooshort++;
|
|---|
| 458 | goto end_error_free_m;
|
|---|
| 459 | }
|
|---|
| 460 |
|
|---|
| 461 | m->m_len -= hlen;
|
|---|
| 462 | m->m_data += hlen;
|
|---|
| 463 |
|
|---|
| 464 | if (cksum(m, icmplen))
|
|---|
| 465 | {
|
|---|
| 466 | icmpstat.icps_checksum++;
|
|---|
| 467 | goto end_error_free_m;
|
|---|
| 468 | }
|
|---|
| 469 |
|
|---|
| 470 | /* are we guaranteed to have ICMP header in first mbuf? be safe. */
|
|---|
| 471 | m_copydata(m, 0, sizeof(icmp_type), (caddr_t)&icmp_type);
|
|---|
| 472 |
|
|---|
| 473 | m->m_len += hlen;
|
|---|
| 474 | m->m_data -= hlen;
|
|---|
| 475 |
|
|---|
| 476 | /* icmpstat.icps_inhist[icp->icmp_type]++; */
|
|---|
| 477 | /* code = icp->icmp_code; */
|
|---|
| 478 |
|
|---|
| 479 | LogFlow(("icmp_type = %d\n", icmp_type));
|
|---|
| 480 | switch (icmp_type)
|
|---|
| 481 | {
|
|---|
| 482 | case ICMP_ECHO:
|
|---|
| 483 | ip->ip_len += hlen; /* since ip_input subtracts this */
|
|---|
| 484 | dst = ip->ip_dst.s_addr;
|
|---|
| 485 | if ( CTL_CHECK(dst, CTL_ALIAS)
|
|---|
| 486 | || CTL_CHECK(dst, CTL_DNS)
|
|---|
| 487 | || CTL_CHECK(dst, CTL_TFTP))
|
|---|
| 488 | {
|
|---|
| 489 | /* Don't reply to ping requests for the hosts loopback interface if it is disabled. */
|
|---|
| 490 | if ( CTL_CHECK(dst, CTL_ALIAS)
|
|---|
| 491 | && !pData->fLocalhostReachable)
|
|---|
| 492 | goto done;
|
|---|
| 493 |
|
|---|
| 494 | uint8_t echo_reply = ICMP_ECHOREPLY;
|
|---|
| 495 | m_copyback(pData, m, hlen + RT_OFFSETOF(struct icmp, icmp_type),
|
|---|
| 496 | sizeof(echo_reply), (caddr_t)&echo_reply);
|
|---|
| 497 | ip->ip_dst.s_addr = ip->ip_src.s_addr;
|
|---|
| 498 | ip->ip_src.s_addr = dst;
|
|---|
| 499 | icmp_reflect(pData, m);
|
|---|
| 500 | m = NULL; /* m was consumed and freed */
|
|---|
| 501 | goto done;
|
|---|
| 502 | }
|
|---|
| 503 |
|
|---|
| 504 | #ifdef RT_OS_WINDOWS
|
|---|
| 505 | {
|
|---|
| 506 | icmpwin_ping(pData, m, hlen);
|
|---|
| 507 | break; /* free mbuf */
|
|---|
| 508 | }
|
|---|
| 509 | #else
|
|---|
| 510 | {
|
|---|
| 511 | struct icmp *icp;
|
|---|
| 512 | struct sockaddr_in addr;
|
|---|
| 513 |
|
|---|
| 514 | /* XXX: FIXME: this is bogus, see CTL_CHECKs above */
|
|---|
| 515 | addr.sin_family = AF_INET;
|
|---|
| 516 | if ((ip->ip_dst.s_addr & RT_H2N_U32(pData->netmask)) == pData->special_addr.s_addr)
|
|---|
| 517 | {
|
|---|
| 518 | /* It's an alias */
|
|---|
| 519 | switch (RT_N2H_U32(ip->ip_dst.s_addr) & ~pData->netmask)
|
|---|
| 520 | {
|
|---|
| 521 | case CTL_DNS:
|
|---|
| 522 | case CTL_ALIAS:
|
|---|
| 523 | default:
|
|---|
| 524 | addr.sin_addr = loopback_addr;
|
|---|
| 525 | break;
|
|---|
| 526 | }
|
|---|
| 527 | }
|
|---|
| 528 | else
|
|---|
| 529 | addr.sin_addr.s_addr = ip->ip_dst.s_addr;
|
|---|
| 530 |
|
|---|
| 531 | if (m->m_next)
|
|---|
| 532 | {
|
|---|
| 533 | icp_buf = RTMemAlloc(icmplen);
|
|---|
| 534 | if (!icp_buf)
|
|---|
| 535 | {
|
|---|
| 536 | Log(("NAT: not enought memory to allocate the buffer\n"));
|
|---|
| 537 | goto end_error_free_m;
|
|---|
| 538 | }
|
|---|
| 539 | m_copydata(m, hlen, icmplen, icp_buf);
|
|---|
| 540 | icp = (struct icmp *)icp_buf;
|
|---|
| 541 | }
|
|---|
| 542 | else
|
|---|
| 543 | icp = (struct icmp *)(mtod(m, char *) + hlen);
|
|---|
| 544 |
|
|---|
| 545 | if (pData->icmp_socket.s != -1)
|
|---|
| 546 | {
|
|---|
| 547 | static bool fIcmpSocketErrorReported;
|
|---|
| 548 | int ttl;
|
|---|
| 549 | int status;
|
|---|
| 550 | ssize_t rc;
|
|---|
| 551 |
|
|---|
| 552 | ttl = ip->ip_ttl;
|
|---|
| 553 | Log(("NAT/ICMP: try to set TTL(%d)\n", ttl));
|
|---|
| 554 | status = setsockopt(pData->icmp_socket.s, IPPROTO_IP, IP_TTL,
|
|---|
| 555 | (void *)&ttl, sizeof(ttl));
|
|---|
| 556 | if (status < 0)
|
|---|
| 557 | Log(("NAT: Error (%s) occurred while setting TTL attribute of IP packet\n",
|
|---|
| 558 | strerror(errno)));
|
|---|
| 559 | rc = sendto(pData->icmp_socket.s, icp, icmplen, 0,
|
|---|
| 560 | (struct sockaddr *)&addr, sizeof(addr));
|
|---|
| 561 | if (rc >= 0)
|
|---|
| 562 | {
|
|---|
| 563 | icmp_attach(pData, m);
|
|---|
| 564 | m = NULL; /* m was stashed away for safekeeping */
|
|---|
| 565 | goto done;
|
|---|
| 566 | }
|
|---|
| 567 |
|
|---|
| 568 |
|
|---|
| 569 | if (!fIcmpSocketErrorReported)
|
|---|
| 570 | {
|
|---|
| 571 | LogRel(("NAT: icmp_input udp sendto tx errno = %d (%s)\n",
|
|---|
| 572 | errno, strerror(errno)));
|
|---|
| 573 | fIcmpSocketErrorReported = true;
|
|---|
| 574 | }
|
|---|
| 575 | icmp_error(pData, m, ICMP_UNREACH, ICMP_UNREACH_NET, 0, strerror(errno));
|
|---|
| 576 | m = NULL; /* m was consumed and freed */
|
|---|
| 577 | goto done;
|
|---|
| 578 | }
|
|---|
| 579 | }
|
|---|
| 580 | #endif /* !RT_OS_WINDOWS */
|
|---|
| 581 | break;
|
|---|
| 582 | case ICMP_UNREACH:
|
|---|
| 583 | case ICMP_TIMXCEED:
|
|---|
| 584 | /* @todo(vvl): both up cases comes from guest,
|
|---|
| 585 | * indeed right solution would be find the socket
|
|---|
| 586 | * corresponding to ICMP data and close it.
|
|---|
| 587 | */
|
|---|
| 588 | case ICMP_PARAMPROB:
|
|---|
| 589 | case ICMP_SOURCEQUENCH:
|
|---|
| 590 | case ICMP_TSTAMP:
|
|---|
| 591 | case ICMP_MASKREQ:
|
|---|
| 592 | case ICMP_REDIRECT:
|
|---|
| 593 | icmpstat.icps_notsupp++;
|
|---|
| 594 | break;
|
|---|
| 595 |
|
|---|
| 596 | default:
|
|---|
| 597 | icmpstat.icps_badtype++;
|
|---|
| 598 | } /* switch */
|
|---|
| 599 |
|
|---|
| 600 | end_error_free_m:
|
|---|
| 601 | if (m != NULL)
|
|---|
| 602 | m_freem(pData, m);
|
|---|
| 603 |
|
|---|
| 604 | done:
|
|---|
| 605 | if (icp_buf)
|
|---|
| 606 | RTMemFree(icp_buf);
|
|---|
| 607 | }
|
|---|
| 608 |
|
|---|
| 609 |
|
|---|
| 610 | /**
|
|---|
| 611 | * Send an ICMP message in response to a situation
|
|---|
| 612 | *
|
|---|
| 613 | * RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header. MAY send more (we do).
|
|---|
| 614 | * MUST NOT change this header information.
|
|---|
| 615 | * MUST NOT reply to a multicast/broadcast IP address.
|
|---|
| 616 | * MUST NOT reply to a multicast/broadcast MAC address.
|
|---|
| 617 | * MUST reply to only the first fragment.
|
|---|
| 618 | *
|
|---|
| 619 | * Send ICMP_UNREACH back to the source regarding msrc.
|
|---|
| 620 | * It is reported as the bad ip packet. The header should
|
|---|
| 621 | * be fully correct and in host byte order.
|
|---|
| 622 | * ICMP fragmentation is illegal.
|
|---|
| 623 | *
|
|---|
| 624 | * @note: implementation note: MSIZE is 256 bytes (minimal buffer).
|
|---|
| 625 | * We always truncate original payload to 8 bytes required by the RFC,
|
|---|
| 626 | * so the largest possible datagram is 14 (ethernet) + 20 (ip) +
|
|---|
| 627 | * 8 (icmp) + 60 (max original ip with options) + 8 (original payload)
|
|---|
| 628 | * = 110 bytes which fits into sinlge mbuf.
|
|---|
| 629 | *
|
|---|
| 630 | * @note This function will free msrc!
|
|---|
| 631 | */
|
|---|
| 632 |
|
|---|
| 633 | void icmp_error(PNATState pData, struct mbuf *msrc, u_char type, u_char code, int minsize, const char *message)
|
|---|
| 634 | {
|
|---|
| 635 | unsigned ohlen, olen;
|
|---|
| 636 | struct mbuf *m;
|
|---|
| 637 | struct ip *oip, *ip;
|
|---|
| 638 | struct icmp *icp;
|
|---|
| 639 | void *payload;
|
|---|
| 640 | RT_NOREF(minsize);
|
|---|
| 641 |
|
|---|
| 642 | LogFlow(("icmp_error: msrc = %p, msrc_len = %d\n",
|
|---|
| 643 | (void *)msrc, msrc ? msrc->m_len : 0));
|
|---|
| 644 |
|
|---|
| 645 | if (RT_UNLIKELY(msrc == NULL))
|
|---|
| 646 | goto end_error;
|
|---|
| 647 |
|
|---|
| 648 | M_ASSERTPKTHDR(msrc);
|
|---|
| 649 |
|
|---|
| 650 | if ( type != ICMP_UNREACH
|
|---|
| 651 | && type != ICMP_TIMXCEED
|
|---|
| 652 | && type != ICMP_SOURCEQUENCH)
|
|---|
| 653 | goto end_error;
|
|---|
| 654 |
|
|---|
| 655 | oip = mtod(msrc, struct ip *);
|
|---|
| 656 | LogFunc(("msrc: %RTnaipv4 -> %RTnaipv4\n", oip->ip_src, oip->ip_dst));
|
|---|
| 657 |
|
|---|
| 658 | if (oip->ip_src.s_addr == INADDR_ANY)
|
|---|
| 659 | goto end_error;
|
|---|
| 660 |
|
|---|
| 661 | if (oip->ip_off & IP_OFFMASK)
|
|---|
| 662 | goto end_error; /* Only reply to fragment 0 */
|
|---|
| 663 |
|
|---|
| 664 | ohlen = oip->ip_hl * 4;
|
|---|
| 665 | AssertStmt(ohlen >= sizeof(struct ip), goto end_error);
|
|---|
| 666 |
|
|---|
| 667 | olen = oip->ip_len;
|
|---|
| 668 | AssertStmt(olen >= ohlen, goto end_error);
|
|---|
| 669 |
|
|---|
| 670 | if (oip->ip_p == IPPROTO_ICMP)
|
|---|
| 671 | {
|
|---|
| 672 | struct icmp *oicp = (struct icmp *)((char *)oip + ohlen);
|
|---|
| 673 | /*
|
|---|
| 674 | * Assume any unknown ICMP type is an error. This isn't
|
|---|
| 675 | * specified by the RFC, but think about it..
|
|---|
| 676 | */
|
|---|
| 677 | if (oicp->icmp_type > ICMP_MAXTYPE || icmp_flush[oicp->icmp_type])
|
|---|
| 678 | goto end_error;
|
|---|
| 679 | }
|
|---|
| 680 |
|
|---|
| 681 | /* undo byte order conversions done in ip_input() */
|
|---|
| 682 | HTONS(oip->ip_len);
|
|---|
| 683 | HTONS(oip->ip_id);
|
|---|
| 684 | HTONS(oip->ip_off);
|
|---|
| 685 |
|
|---|
| 686 | m = m_gethdr(pData, M_NOWAIT, MT_HEADER);
|
|---|
| 687 | if (RT_UNLIKELY(m == NULL))
|
|---|
| 688 | goto end_error;
|
|---|
| 689 |
|
|---|
| 690 | m->m_flags |= M_SKIP_FIREWALL;
|
|---|
| 691 | m->m_data += if_maxlinkhdr;
|
|---|
| 692 |
|
|---|
| 693 | ip = mtod(m, struct ip *);
|
|---|
| 694 | m->m_pkthdr.header = (void *)ip;
|
|---|
| 695 |
|
|---|
| 696 | /* fill in ip (ip_output0() does the boilerplate for us) */
|
|---|
| 697 | ip->ip_tos = ((oip->ip_tos & 0x1E) | 0xC0); /* high priority for errors */
|
|---|
| 698 | /* ip->ip_len will be set later */
|
|---|
| 699 | ip->ip_off = 0;
|
|---|
| 700 | ip->ip_ttl = MAXTTL;
|
|---|
| 701 | ip->ip_p = IPPROTO_ICMP;
|
|---|
| 702 | ip->ip_src = alias_addr;
|
|---|
| 703 | ip->ip_dst = oip->ip_src;
|
|---|
| 704 |
|
|---|
| 705 | /* fill in icmp */
|
|---|
| 706 | icp = (struct icmp *)((char *)ip + sizeof(*ip));
|
|---|
| 707 | icp->icmp_type = type;
|
|---|
| 708 | icp->icmp_code = code;
|
|---|
| 709 | icp->icmp_id = 0;
|
|---|
| 710 | icp->icmp_seq = 0;
|
|---|
| 711 |
|
|---|
| 712 | /* fill in icmp payload: original ip header plus 8 bytes of its payload */
|
|---|
| 713 | if (olen > ohlen + 8)
|
|---|
| 714 | olen = ohlen + 8;
|
|---|
| 715 | payload = (void *)((char *)icp + ICMP_MINLEN);
|
|---|
| 716 | memcpy(payload, oip, olen);
|
|---|
| 717 |
|
|---|
| 718 | /*
|
|---|
| 719 | * Original code appended this message after the payload. This
|
|---|
| 720 | * might have been a good idea for real slirp, as it provided a
|
|---|
| 721 | * communication channel with the remote host. But 90s are over.
|
|---|
| 722 | */
|
|---|
| 723 | NOREF(message);
|
|---|
| 724 |
|
|---|
| 725 | /* hide ip header for icmp checksum calculation */
|
|---|
| 726 | m->m_data += sizeof(struct ip);
|
|---|
| 727 | m->m_len = ICMP_MINLEN + /* truncated */ olen;
|
|---|
| 728 |
|
|---|
| 729 | icp->icmp_cksum = 0;
|
|---|
| 730 | icp->icmp_cksum = cksum(m, m->m_len);
|
|---|
| 731 |
|
|---|
| 732 | /* reveal ip header */
|
|---|
| 733 | m->m_data -= sizeof(struct ip);
|
|---|
| 734 | m->m_len += sizeof(struct ip);
|
|---|
| 735 | ip->ip_len = m->m_len;
|
|---|
| 736 |
|
|---|
| 737 | (void) ip_output0(pData, (struct socket *)NULL, m, 1);
|
|---|
| 738 |
|
|---|
| 739 | icmpstat.icps_reflect++;
|
|---|
| 740 |
|
|---|
| 741 | /* clear source datagramm in positive branch */
|
|---|
| 742 | m_freem(pData, msrc);
|
|---|
| 743 | LogFlowFuncLeave();
|
|---|
| 744 | return;
|
|---|
| 745 |
|
|---|
| 746 | end_error:
|
|---|
| 747 |
|
|---|
| 748 | /*
|
|---|
| 749 | * clear source datagramm in case if some of requirement haven't been met.
|
|---|
| 750 | */
|
|---|
| 751 | if (msrc)
|
|---|
| 752 | m_freem(pData, msrc);
|
|---|
| 753 |
|
|---|
| 754 | {
|
|---|
| 755 | static bool fIcmpErrorReported;
|
|---|
| 756 | if (!fIcmpErrorReported)
|
|---|
| 757 | {
|
|---|
| 758 | LogRel(("NAT: Error occurred while sending ICMP error message\n"));
|
|---|
| 759 | fIcmpErrorReported = true;
|
|---|
| 760 | }
|
|---|
| 761 | }
|
|---|
| 762 | LogFlowFuncLeave();
|
|---|
| 763 | }
|
|---|
| 764 |
|
|---|
| 765 | /*
|
|---|
| 766 | * Reflect the ip packet back to the source
|
|---|
| 767 | * Note: m isn't duplicated by this method and more delivered to ip_output then.
|
|---|
| 768 | */
|
|---|
| 769 | void
|
|---|
| 770 | icmp_reflect(PNATState pData, struct mbuf *m)
|
|---|
| 771 | {
|
|---|
| 772 | register struct ip *ip = mtod(m, struct ip *);
|
|---|
| 773 | int hlen = ip->ip_hl << 2;
|
|---|
| 774 | register struct icmp *icp;
|
|---|
| 775 | LogFlowFunc(("ENTER: m:%p\n", m));
|
|---|
| 776 |
|
|---|
| 777 | /*
|
|---|
| 778 | * Send an icmp packet back to the ip level,
|
|---|
| 779 | * after supplying a checksum.
|
|---|
| 780 | */
|
|---|
| 781 | m->m_data += hlen;
|
|---|
| 782 | m->m_len -= hlen;
|
|---|
| 783 | icp = mtod(m, struct icmp *);
|
|---|
| 784 |
|
|---|
| 785 | icp->icmp_cksum = 0;
|
|---|
| 786 | icp->icmp_cksum = cksum(m, ip->ip_len - hlen);
|
|---|
| 787 |
|
|---|
| 788 | m->m_data -= hlen;
|
|---|
| 789 | m->m_len += hlen;
|
|---|
| 790 |
|
|---|
| 791 | (void) ip_output(pData, (struct socket *)NULL, m);
|
|---|
| 792 |
|
|---|
| 793 | icmpstat.icps_reflect++;
|
|---|
| 794 | LogFlowFuncLeave();
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|---|
| 795 | }
|
|---|
