| 1 | /* $Id: ip_output.c 93115 2022-01-01 11:31:46Z vboxsync $ */
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| 2 | /** @file
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| 3 | * NAT - IP output.
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| 4 | */
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| 5 |
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| 6 | /*
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| 7 | * Copyright (C) 2006-2022 Oracle Corporation
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| 8 | *
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| 9 | * This file is part of VirtualBox Open Source Edition (OSE), as
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| 10 | * available from http://www.virtualbox.org. This file is free software;
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| 11 | * you can redistribute it and/or modify it under the terms of the GNU
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| 12 | * General Public License (GPL) as published by the Free Software
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| 13 | * Foundation, in version 2 as it comes in the "COPYING" file of the
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| 14 | * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
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| 15 | * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
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| 16 | */
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| 17 |
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| 18 | /*
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| 19 | * This code is based on:
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| 20 | *
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| 21 | * Copyright (c) 1982, 1986, 1988, 1990, 1993
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| 22 | * The Regents of the University of California. All rights reserved.
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| 23 | *
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| 24 | * Redistribution and use in source and binary forms, with or without
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| 25 | * modification, are permitted provided that the following conditions
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| 26 | * are met:
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| 27 | * 1. Redistributions of source code must retain the above copyright
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| 28 | * notice, this list of conditions and the following disclaimer.
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| 29 | * 2. Redistributions in binary form must reproduce the above copyright
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| 30 | * notice, this list of conditions and the following disclaimer in the
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| 31 | * documentation and/or other materials provided with the distribution.
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| 32 | * 3. All advertising materials mentioning features or use of this software
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| 33 | * must display the following acknowledgement:
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| 34 | * This product includes software developed by the University of
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| 35 | * California, Berkeley and its contributors.
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| 36 | * 4. Neither the name of the University nor the names of its contributors
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| 37 | * may be used to endorse or promote products derived from this software
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| 38 | * without specific prior written permission.
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| 39 | *
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| 40 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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| 41 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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| 42 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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| 43 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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| 44 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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| 45 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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| 46 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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| 47 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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| 48 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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| 49 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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| 50 | * SUCH DAMAGE.
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| 51 | *
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| 52 | * @(#)ip_output.c 8.3 (Berkeley) 1/21/94
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| 53 | * ip_output.c,v 1.9 1994/11/16 10:17:10 jkh Exp
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| 54 | */
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| 55 |
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| 56 | /*
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| 57 | * Changes and additions relating to SLiRP are
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| 58 | * Copyright (c) 1995 Danny Gasparovski.
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| 59 | *
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| 60 | * Please read the file COPYRIGHT for the
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| 61 | * terms and conditions of the copyright.
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| 62 | */
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| 63 |
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| 64 | #include <slirp.h>
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| 65 | #include <iprt/errcore.h>
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| 66 | #include "alias.h"
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| 67 |
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| 68 | static const uint8_t broadcast_ethaddr[6] =
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| 69 | {
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| 70 | 0xff, 0xff, 0xff, 0xff, 0xff, 0xff
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| 71 | };
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| 72 |
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| 73 | static int rt_lookup_in_cache(PNATState pData, uint32_t dst, uint8_t *ether)
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| 74 | {
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| 75 | int rc;
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| 76 | LogFlowFunc(("ENTER: dst:%RTnaipv4, ether:%RTmac\n", dst, ether));
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| 77 | if (dst == INADDR_BROADCAST)
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| 78 | {
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| 79 | memcpy(ether, broadcast_ethaddr, ETH_ALEN);
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| 80 | LogFlowFunc(("LEAVE: VINF_SUCCESS\n"));
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| 81 | return VINF_SUCCESS;
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| 82 | }
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| 83 |
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| 84 | rc = slirp_arp_lookup_ether_by_ip(pData, dst, ether);
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| 85 | if (RT_SUCCESS(rc))
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| 86 | {
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| 87 | LogFlowFunc(("LEAVE: %Rrc\n", rc));
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| 88 | return rc;
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| 89 | }
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| 90 |
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| 91 | rc = bootp_cache_lookup_ether_by_ip(pData, dst, ether);
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| 92 | if (RT_SUCCESS(rc))
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| 93 | {
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| 94 | LogFlowFunc(("LEAVE: %Rrc\n", rc));
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| 95 | return rc;
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| 96 | }
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| 97 | /*
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| 98 | * no chance to send this packet, sorry, we will request ether address via ARP
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| 99 | */
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| 100 | slirp_arp_who_has(pData, dst);
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| 101 | LogFlowFunc(("LEAVE: VERR_NOT_FOUND\n"));
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| 102 | return VERR_NOT_FOUND;
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| 103 | }
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| 104 |
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| 105 | /*
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| 106 | * IP output. The packet in mbuf chain m contains a skeletal IP
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| 107 | * header (with len, off, ttl, proto, tos, src, dst).
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| 108 | * The mbuf chain containing the packet will be freed.
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| 109 | * The mbuf opt, if present, will not be freed.
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| 110 | */
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| 111 | int
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| 112 | ip_output(PNATState pData, struct socket *so, struct mbuf *m0)
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| 113 | {
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| 114 | return ip_output0(pData, so, m0, 0);
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| 115 | }
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| 116 |
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| 117 | /* This function will free m0! */
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| 118 | int
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| 119 | ip_output0(PNATState pData, struct socket *so, struct mbuf *m0, int urg)
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| 120 | {
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| 121 | register struct ip *ip;
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| 122 | register struct mbuf *m = m0;
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| 123 | register int hlen = sizeof(struct ip);
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| 124 | int len, off, error = 0;
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| 125 | struct ethhdr *eh = NULL;
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| 126 | uint8_t eth_dst[ETH_ALEN];
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| 127 | int rc = 1;
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| 128 |
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| 129 | STAM_PROFILE_START(&pData->StatIP_output, a);
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| 130 |
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| 131 | #ifdef LOG_ENABLED
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| 132 | LogFlowFunc(("ip_output: so = %R[natsock], m0 = %p\n", so, m0));
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| 133 | #else
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| 134 | NOREF(so);
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| 135 | #endif
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| 136 |
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| 137 | M_ASSERTPKTHDR(m);
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| 138 | Assert(m->m_pkthdr.header);
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| 139 |
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| 140 | #if 0 /* We do no options */
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| 141 | if (opt)
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| 142 | {
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| 143 | m = ip_insertoptions(m, opt, &len);
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| 144 | hlen = len;
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| 145 | }
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| 146 | #endif
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| 147 | ip = mtod(m, struct ip *);
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| 148 | LogFunc(("ip(src:%RTnaipv4, dst:%RTnaipv4)\n", ip->ip_src, ip->ip_dst));
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| 149 | /*
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| 150 | * Fill in IP header.
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| 151 | */
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| 152 | ip->ip_v = IPVERSION;
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| 153 | ip->ip_off &= IP_DF;
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| 154 | ip->ip_id = RT_H2N_U16(ip_currid);
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| 155 | ip->ip_hl = hlen >> 2;
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| 156 | ip_currid++;
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| 157 | ipstat.ips_localout++;
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| 158 |
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| 159 | /* Current TCP/IP stack hasn't routing information at
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| 160 | * all so we need to calculate destination ethernet address
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| 161 | */
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| 162 | rc = rt_lookup_in_cache(pData, ip->ip_dst.s_addr, eth_dst);
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| 163 | if (RT_FAILURE(rc))
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| 164 | goto exit_drop_package;
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| 165 |
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| 166 | eh = (struct ethhdr *)(m->m_data - ETH_HLEN);
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| 167 | /*
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| 168 | * If small enough for interface, can just send directly.
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| 169 | */
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| 170 | if ((u_int16_t)ip->ip_len <= if_mtu)
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| 171 | {
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| 172 | ip->ip_len = RT_H2N_U16((u_int16_t)ip->ip_len);
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| 173 | ip->ip_off = RT_H2N_U16((u_int16_t)ip->ip_off);
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| 174 | ip->ip_sum = 0;
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| 175 | ip->ip_sum = cksum(m, hlen);
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| 176 |
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| 177 | if (!(m->m_flags & M_SKIP_FIREWALL)){
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| 178 | STAM_PROFILE_START(&pData->StatALIAS_output, b);
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| 179 | rc = LibAliasOut(pData->proxy_alias, mtod(m, char *), m_length(m, NULL));
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| 180 | if (rc == PKT_ALIAS_IGNORED)
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| 181 | {
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| 182 | Log(("NAT: packet was droppped\n"));
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| 183 | goto exit_drop_package;
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| 184 | }
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| 185 | STAM_PROFILE_STOP(&pData->StatALIAS_output, b);
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| 186 | }
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| 187 | else
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| 188 | m->m_flags &= ~M_SKIP_FIREWALL;
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| 189 |
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| 190 | memcpy(eh->h_source, eth_dst, ETH_ALEN);
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| 191 |
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| 192 | LogFlowFunc(("ip(ip_src:%RTnaipv4, ip_dst:%RTnaipv4)\n",
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| 193 | ip->ip_src, ip->ip_dst));
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| 194 | if_encap(pData, ETH_P_IP, m, urg? ETH_ENCAP_URG : 0);
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| 195 | goto done;
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| 196 | }
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| 197 |
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| 198 | /*
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| 199 | * Too large for interface; fragment if possible.
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| 200 | * Must be able to put at least 8 bytes per fragment.
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| 201 | */
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| 202 | if (ip->ip_off & IP_DF)
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| 203 | {
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| 204 | error = -1;
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| 205 | ipstat.ips_cantfrag++;
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| 206 | goto exit_drop_package;
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| 207 | }
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| 208 |
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| 209 | len = (if_mtu - hlen) &~ 7; /* ip databytes per packet */
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| 210 | if (len < 8)
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| 211 | {
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| 212 | error = -1;
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| 213 | goto exit_drop_package;
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| 214 | }
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| 215 |
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| 216 | {
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| 217 | int mhlen, firstlen = len;
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| 218 | struct mbuf **mnext = &m->m_nextpkt;
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| 219 | char *buf; /* intermediate buffer we'll use for a copy of the original packet */
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| 220 | /*
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| 221 | * Loop through length of segment after first fragment,
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| 222 | * make new header and copy data of each part and link onto chain.
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| 223 | */
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| 224 | m0 = m;
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| 225 | mhlen = ip->ip_hl << 2;
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| 226 | Log(("NAT:ip:frag: mhlen = %d\n", mhlen));
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| 227 | for (off = hlen + len; off < (u_int16_t)ip->ip_len; off += len)
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| 228 | {
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| 229 | register struct ip *mhip;
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| 230 | m = m_getjcl(pData, M_NOWAIT, MT_HEADER , M_PKTHDR, slirp_size(pData));
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| 231 | if (m == 0)
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| 232 | {
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| 233 | error = -1;
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| 234 | ipstat.ips_odropped++;
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| 235 | goto exit_drop_package;
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| 236 | }
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| 237 | m->m_data += if_maxlinkhdr;
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| 238 | mhip = mtod(m, struct ip *);
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| 239 | *mhip = *ip;
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| 240 | m->m_pkthdr.header = mtod(m, void *);
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| 241 | /* we've calculated eth_dst for first packet */
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| 242 | #if 0 /* No options */
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| 243 | if (hlen > sizeof (struct ip))
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| 244 | {
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| 245 | mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip);
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| 246 | mhip->ip_hl = mhlen >> 2;
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| 247 | }
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| 248 | #endif
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| 249 | m->m_len = mhlen;
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| 250 | mhip->ip_off = ((off - mhlen) >> 3) + (ip->ip_off & ~IP_MF);
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| 251 | if (ip->ip_off & IP_MF)
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| 252 | mhip->ip_off |= IP_MF;
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| 253 | if (off + len >= (u_int16_t)ip->ip_len)
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| 254 | len = (u_int16_t)ip->ip_len - off;
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| 255 | else
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| 256 | mhip->ip_off |= IP_MF;
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| 257 | mhip->ip_len = RT_H2N_U16((u_int16_t)(len + mhlen));
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| 258 |
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| 259 | buf = RTMemAlloc(len);
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| 260 | Log(("NAT:ip:frag: alloc = %d\n", len));
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| 261 | m_copydata(m0, off, len, buf); /* copy to buffer */
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| 262 | Log(("NAT:ip:frag: m_copydata(m0 = %p,off = %d, len = %d,)\n", m0, off, len));
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| 263 |
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| 264 | m->m_data += mhlen;
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| 265 | m->m_len -= mhlen;
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| 266 | m_copyback(pData, m, 0, len, buf); /* copy from buffer */
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| 267 | Log(("NAT:ip:frag: m_copyback(m = %p,, len = %d,)\n", m, len));
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| 268 | m->m_data -= mhlen;
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| 269 | m->m_len += mhlen;
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| 270 | RTMemFree(buf);
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| 271 | Assert((m->m_len == (mhlen + len)));
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| 272 |
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| 273 | mhip->ip_off = RT_H2N_U16((u_int16_t)(mhip->ip_off));
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| 274 | mhip->ip_sum = 0;
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| 275 | mhip->ip_sum = cksum(m, mhlen);
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| 276 | *mnext = m;
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| 277 | mnext = &m->m_nextpkt;
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| 278 | ipstat.ips_ofragments++;
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| 279 | }
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| 280 | /*
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| 281 | * Update first fragment by trimming what's been copied out
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| 282 | * and updating header, then send each fragment (in order).
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| 283 | *
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| 284 | * note: m_adj do all required releases for chained mbufs.
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| 285 | */
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| 286 | m = m0;
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| 287 | m_adj(m, mhlen + firstlen - (u_int16_t)ip->ip_len);
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| 288 | Log(("NAT:ip:frag: m_adj(m(m_len:%d) = %p, len = %d)\n", m->m_len, m, mhlen + firstlen - (u_int16_t)ip->ip_len));
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| 289 | ip->ip_len = RT_H2N_U16((u_int16_t)mhlen + firstlen);
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| 290 | ip->ip_off = RT_H2N_U16((u_int16_t)(ip->ip_off | IP_MF));
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| 291 | ip->ip_sum = 0;
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| 292 | ip->ip_sum = cksum(m, mhlen);
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| 293 |
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| 294 | if (!(m->m_flags & M_SKIP_FIREWALL)){
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| 295 | /** @todo We can't alias all fragments because the way libalias processing
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| 296 | * the fragments brake the sequence. libalias put alias_address to the source
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| 297 | * address of IP header of fragment, while IP header of the first packet is
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| 298 | * is unmodified. That confuses guest's TCP/IP stack and guest drop the sequence.
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| 299 | * Here we're letting libalias to process the first packet and send the rest as is,
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| 300 | * it's exactly the way in of packet are processing in proxyonly way.
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| 301 | * Here we need investigate what should be done to avoid such behavior and find right
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| 302 | * solution.
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| 303 | */
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| 304 | int rcLa;
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| 305 |
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| 306 | rcLa = LibAliasOut(pData->proxy_alias, mtod(m, char *), m->m_len);
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| 307 | if (rcLa == PKT_ALIAS_IGNORED)
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| 308 | {
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| 309 | Log(("NAT: packet was droppped\n"));
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| 310 | goto exit_drop_package;
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| 311 | }
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| 312 | Log2(("NAT: LibAlias return %d\n", rcLa));
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| 313 | }
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| 314 | else
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| 315 | m->m_flags &= ~M_SKIP_FIREWALL;
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| 316 | for (m = m0; m; m = m0)
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| 317 | {
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| 318 | m0 = m->m_nextpkt;
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| 319 | m->m_nextpkt = 0;
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| 320 | if (error == 0)
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| 321 | {
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| 322 | m->m_data -= ETH_HLEN;
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| 323 | eh = mtod(m, struct ethhdr *);
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| 324 | m->m_data += ETH_HLEN;
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| 325 | memcpy(eh->h_source, eth_dst, ETH_ALEN);
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| 326 |
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| 327 | Log(("NAT:ip:frag: if_encap(,,m(m_len = %d) = %p,0)\n", m->m_len, m));
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| 328 | if_encap(pData, ETH_P_IP, m, 0);
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| 329 | }
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| 330 | else
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| 331 | m_freem(pData, m);
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| 332 | }
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| 333 |
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| 334 | if (error == 0)
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| 335 | ipstat.ips_fragmented++;
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| 336 | }
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| 337 |
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| 338 | done:
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| 339 | STAM_PROFILE_STOP(&pData->StatIP_output, a);
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| 340 | LogFlowFunc(("LEAVE: %d\n", error));
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| 341 | return error;
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| 342 |
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| 343 | exit_drop_package:
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| 344 | m_freem(pData, m0);
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| 345 | STAM_PROFILE_STOP(&pData->StatIP_output, a);
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| 346 | LogFlowFunc(("LEAVE: %d\n", error));
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| 347 | return error;
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| 348 | }
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