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/***************************************************************************
* nsock_pcap.h -- Header for pcap operations functions from *
* the nsock parallel socket event library *
* *
***********************IMPORTANT NSOCK LICENSE TERMS***********************
*
* The nsock parallel socket event library is (C) 1999-2023 Nmap Software LLC
* This library is free software; you may redistribute and/or modify it under
* the terms of the GNU General Public License as published by the Free Software
* Foundation; Version 2. This guarantees your right to use, modify, and
* redistribute this software under certain conditions. If this license is
* unacceptable to you, Nmap Software LLC may be willing to sell alternative
* licenses (contact sales@nmap.com ).
*
* As a special exception to the GPL terms, Nmap Software LLC grants permission
* to link the code of this program with any version of the OpenSSL library
* which is distributed under a license identical to that listed in the included
* docs/licenses/OpenSSL.txt file, and distribute linked combinations including
* the two. You must obey the GNU GPL in all respects for all of the code used
* other than OpenSSL. If you modify this file, you may extend this exception to
* your version of the file, but you are not obligated to do so.
*
* If you received these files with a written license agreement stating terms
* other than the (GPL) terms above, then that alternative license agreement
* takes precedence over this comment.
*
* Source is provided to this software because we believe users have a right to
* know exactly what a program is going to do before they run it. This also
* allows you to audit the software for security holes.
*
* Source code also allows you to port Nmap to new platforms, fix bugs, and add
* new features. You are highly encouraged to send your changes to the
* dev@nmap.org mailing list for possible incorporation into the main
* distribution. By sending these changes to Fyodor or one of the Insecure.Org
* development mailing lists, or checking them into the Nmap source code
* repository, it is understood (unless you specify otherwise) that you are
* offering the Nmap Project (Nmap Software LLC) the unlimited, non-exclusive
* right to reuse, modify, and relicense the code. Nmap will always be available
* Open Source, but this is important because the inability to relicense code
* has caused devastating problems for other Free Software projects (such as KDE
* and NASM). We also occasionally relicense the code to third parties as
* discussed above. If you wish to specify special license conditions of your
* contributions, just say so when you send them.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License v2.0 for more
* details (http://www.gnu.org/licenses/gpl-2.0.html).
*
***************************************************************************/
/* $Id$ */
#ifndef NSOCK_PCAP_H
#define NSOCK_PCAP_H
#include "nsock_internal.h"
#ifdef HAVE_PCAP
#include "pcap.h"
#include <string.h>
#include <stdarg.h>
/*
* There are three possible ways to read packets from pcap descriptor:
* - select() on descriptor:
* this one is of course the best, but there are systems that
* don't support this like WIN32. This works perfectly for Linux.
*
* - select() + some hacks:
* this one is hack for older bsd systems,
* Descriptor *must* be set in nonblocking mode.
*
* - never do select():
* this one is for WIN32 and other systems that return descriptor -1
* from pcap_get_selectable_fd().
* In this case descriptor *must* be set in nonblocking mode.
* If that fails than we can't do any sniffing from that box.
*
* In any case we try to set descriptor to non-blocking mode.
*/
/* Returns whether the system supports pcap_get_selectable_fd() properly */
#if !defined(WIN32) && !defined(SOLARIS_BPF_PCAP_CAPTURE)
#define PCAP_CAN_DO_SELECT 1
#endif
/* In some systems (like Windows), the pcap descriptor is not selectable.
* Therefore, we cannot just select() on it and expect it to wake us up and
* deliver a packet, but we need to poll it continuously. This define sets the
* frequency, in milliseconds, at which the pcap handle is polled to determine
* if there are any captured packets. Note that this is only used when
* PCAP_CAN_DO_SELECT is not defined and therefore it has no effect on systems
* like Linux.
*/
#define PCAP_POLL_INTERVAL 2
/* Note that on most versions of most BSDs (including Mac OS X) select() and
* poll() do not work correctly on BPF devices; pcap_get_selectable_fd() will
* return a file descriptor on most of those versions (the exceptions being
* FreeBSD 4.3 and 4.4), a simple select() or poll() will not return even after
* a timeout specified in pcap_open_live() expires. To work around this, an
* application that uses select() or poll() to wait for packets to arrive must
* put the pcap_t in non-blocking mode, and must arrange that the select() or
* poll() have a timeout less than or equal to the timeout specified in
* pcap_open_live(), and must try to read packets after that timeout expires,
* regardless of whether select() or poll() indicated that the file descriptor
* for the pcap_t is ready to be read or not. (That workaround will not work in
* FreeBSD 4.3 and later; however, in FreeBSD 4.6 and later, select() and poll()
* work correctly on BPF devices, so the workaround isn't necessary, although it
* does no harm.)
*/
#if defined(MACOSX) || defined(FREEBSD) || defined(OPENBSD)
/* Well, now select() is not receiving any pcap events on MACOSX, but maybe it
* will someday :) in both cases. It never hurts to enable this feature. It just
* has performance penalty. */
#define PCAP_BSD_SELECT_HACK 1
#endif
/* Returns whether the packet receive time value obtained from libpcap
* (and thus by readip_pcap()) should be considered valid. When
* invalid (Windows and Amiga), readip_pcap returns the time you called it. */
#if !defined(WIN32) && !defined(__amigaos__)
#define PCAP_RECV_TIMEVAL_VALID 1
#endif
typedef struct{
pcap_t *pt;
int pcap_desc;
/* Like the corresponding member in iod, when this reaches 0 we stop
* watching the socket for readability. */
int readsd_count;
int datalink;
int l3_offset;
int snaplen;
char *pcap_device;
} mspcap;
typedef struct{
struct timeval ts;
int caplen;
int len;
const unsigned char *packet; /* caplen bytes */
} nsock_pcap;
int do_actual_pcap_read(struct nevent *nse);
#endif /* HAVE_PCAP */
#endif /* NSOCK_PCAP_H */
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