1de7b4b805
Mainly focus on files that use BSD 2-Clause license, however the tool I was using misidentified many licenses so this was mostly a manual - error prone - task. The Software Package Data Exchange (SPDX) group provides a specification to make it easier for automated tools to detect and summarize well known opensource licenses. We are gradually adopting the specification, noting that the tags are considered only advisory and do not, in any way, superceed or replace the license texts. No functional change intended.
97 lines
3.2 KiB
C
97 lines
3.2 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 2010 Bjoern A. Zeeb <bz@FreeBSD.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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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* $FreeBSD$
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*/
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#include <string.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include "findsaddr.h"
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#include "traceroute.h"
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/*
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* Return the source address for the given destination address.
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*
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* This makes use of proper source address selection in the FreeBSD kernel
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* even taking jails into account (sys/netinet/in_pcb.c:in_pcbladdr()).
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* We open a UDP socket, and connect to the destination, letting the kernel
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* do the bind and then read the source IPv4 address using getsockname(2).
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* This has multiple advantages: no need to do PF_ROUTE operations possibly
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* needing special privileges, jails properly taken into account and most
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* important - getting the result the kernel would give us rather than
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* best-guessing ourselves.
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*/
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const char *
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findsaddr(register const struct sockaddr_in *to,
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register struct sockaddr_in *from)
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{
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const char *errstr;
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struct sockaddr_in cto, cfrom;
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int s;
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socklen_t len;
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s = socket(AF_INET, SOCK_DGRAM, 0);
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if (s == -1)
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return ("failed to open DGRAM socket for src addr selection.");
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errstr = NULL;
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len = sizeof(struct sockaddr_in);
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memcpy(&cto, to, len);
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cto.sin_port = htons(65535); /* Dummy port for connect(2). */
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if (connect(s, (struct sockaddr *)&cto, len) == -1) {
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errstr = "failed to connect to peer for src addr selection.";
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goto err;
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}
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if (getsockname(s, (struct sockaddr *)&cfrom, &len) == -1) {
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errstr = "failed to get socket name for src addr selection.";
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goto err;
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}
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if (len != sizeof(struct sockaddr_in) || cfrom.sin_family != AF_INET) {
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errstr = "unexpected address family in src addr selection.";
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goto err;
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}
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/* Update source address for traceroute. */
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setsin(from, cfrom.sin_addr.s_addr);
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err:
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(void) close(s);
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/* No error (string) to return. */
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return (errstr);
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}
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/* end */
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