191 lines
5.1 KiB
Plaintext
191 lines
5.1 KiB
Plaintext
.\" Copyright (c) 1994, 1996, 1997
|
|
.\" The Regents of the University of California. All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that: (1) source code distributions
|
|
.\" retain the above copyright notice and this paragraph in its entirety, (2)
|
|
.\" distributions including binary code include the above copyright notice and
|
|
.\" this paragraph in its entirety in the documentation or other materials
|
|
.\" provided with the distribution, and (3) all advertising materials mentioning
|
|
.\" features or use of this software display the following acknowledgement:
|
|
.\" ``This product includes software developed by the University of California,
|
|
.\" Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
|
|
.\" the University nor the names of its contributors may be used to endorse
|
|
.\" or promote products derived from this software without specific prior
|
|
.\" written permission.
|
|
.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
|
|
.\" WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
|
|
.\" MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
|
|
.\"
|
|
.TH PCAP_FINDALLDEVS 3PCAP "10 January 2014"
|
|
.SH NAME
|
|
pcap_findalldevs, pcap_freealldevs \- get a list of capture devices, and
|
|
free that list
|
|
.SH SYNOPSIS
|
|
.nf
|
|
.ft B
|
|
#include <pcap/pcap.h>
|
|
.ft
|
|
.LP
|
|
.nf
|
|
.ft B
|
|
char errbuf[PCAP_ERRBUF_SIZE];
|
|
.ft
|
|
.LP
|
|
.ft B
|
|
int pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf);
|
|
void pcap_freealldevs(pcap_if_t *alldevs);
|
|
.ft
|
|
.fi
|
|
.SH DESCRIPTION
|
|
.B pcap_findalldevs()
|
|
constructs a list of network devices that can be opened with
|
|
.B pcap_create()
|
|
and
|
|
.B pcap_activate()
|
|
or with
|
|
.BR pcap_open_live() .
|
|
(Note that there may be network devices that cannot be opened by the
|
|
process calling
|
|
.BR pcap_findalldevs() ,
|
|
because, for example, that process does not have sufficient privileges
|
|
to open them for capturing; if so, those devices will not appear on the
|
|
list.)
|
|
If
|
|
.B pcap_findalldevs()
|
|
succeeds, the pointer pointed to by
|
|
.I alldevsp
|
|
is set to point to the first element of the list, or to
|
|
.B NULL
|
|
if no devices were found (this is considered success).
|
|
Each element of the list is of type
|
|
.BR pcap_if_t ,
|
|
and has the following members:
|
|
.RS
|
|
.TP
|
|
.B next
|
|
if not
|
|
.BR NULL ,
|
|
a pointer to the next element in the list;
|
|
.B NULL
|
|
for the last element of the list
|
|
.TP
|
|
.B name
|
|
a pointer to a string giving a name for the device to pass to
|
|
.B pcap_open_live()
|
|
.TP
|
|
.B description
|
|
if not
|
|
.BR NULL ,
|
|
a pointer to a string giving a human-readable description of the device
|
|
.TP
|
|
.B addresses
|
|
a pointer to the first element of a list of network addresses for the
|
|
device,
|
|
or
|
|
.B NULL
|
|
if the device has no addresses
|
|
.TP
|
|
.B flags
|
|
device flags:
|
|
.RS
|
|
.TP
|
|
.B PCAP_IF_LOOPBACK
|
|
set if the device is a loopback interface
|
|
.TP
|
|
.B PCAP_IF_UP
|
|
set if the device is up
|
|
.TP
|
|
.B PCAP_IF_RUNNING
|
|
set if the device is running
|
|
.RE
|
|
.RE
|
|
.PP
|
|
Each element of the list of addresses is of type
|
|
.BR pcap_addr_t ,
|
|
and has the following members:
|
|
.RS
|
|
.TP
|
|
.B next
|
|
if not
|
|
.BR NULL ,
|
|
a pointer to the next element in the list;
|
|
.B NULL
|
|
for the last element of the list
|
|
.TP
|
|
.B addr
|
|
a pointer to a
|
|
.B "struct sockaddr"
|
|
containing an address
|
|
.TP
|
|
.B netmask
|
|
if not
|
|
.BR NULL ,
|
|
a pointer to a
|
|
.B "struct sockaddr"
|
|
that contains the netmask corresponding to the address pointed to by
|
|
.B addr
|
|
.TP
|
|
.B broadaddr
|
|
if not
|
|
.BR NULL ,
|
|
a pointer to a
|
|
.B "struct sockaddr"
|
|
that contains the broadcast address corresponding to the address pointed
|
|
to by
|
|
.BR addr ;
|
|
may be null if the device doesn't support broadcasts
|
|
.TP
|
|
.B dstaddr
|
|
if not
|
|
.BR NULL ,
|
|
a pointer to a
|
|
.B "struct sockaddr"
|
|
that contains the destination address corresponding to the address pointed
|
|
to by
|
|
.BR addr ;
|
|
may be null if the device isn't a point-to-point interface
|
|
.RE
|
|
.PP
|
|
Note that the addresses in the list of addresses might be IPv4
|
|
addresses, IPv6 addresses, or some other type of addresses, so you must
|
|
check the
|
|
.B sa_family
|
|
member of the
|
|
.B "struct sockaddr"
|
|
before interpreting the contents of the address; do not assume that the
|
|
addresses are all IPv4 addresses, or even all IPv4 or IPv6 addresses.
|
|
IPv4 addresses have the value
|
|
.BR AF_INET ,
|
|
IPv6 addresses have the value
|
|
.B AF_INET6
|
|
(which older operating systems that don't support IPv6 might not
|
|
define), and other addresses have other values. Whether other addresses
|
|
are returned, and what types they might have is platform-dependent.
|
|
For IPv4 addresses, the
|
|
.B "struct sockaddr"
|
|
pointer can be interpreted as if it pointed to a
|
|
.BR "struct sockaddr_in" ;
|
|
for IPv6 addresses, it can be interpreted as if it pointed to a
|
|
.BR "struct sockaddr_in6".
|
|
.PP
|
|
The list of devices must be freed with
|
|
.BR pcap_freealldevs() ,
|
|
which frees the list pointed to by
|
|
.IR alldevs .
|
|
.SH RETURN VALUE
|
|
.B pcap_findalldevs()
|
|
returns 0 on success and \-1 on failure; as indicated, finding no
|
|
devices is considered success, rather than failure, so 0 will be
|
|
returned in that case.
|
|
If \-1 is returned,
|
|
.I errbuf
|
|
is filled in with an appropriate error message.
|
|
.I errbuf
|
|
is assumed to be able to hold at least
|
|
.B PCAP_ERRBUF_SIZE
|
|
chars.
|
|
.SH SEE ALSO
|
|
pcap(3PCAP), pcap_create(3PCAP), pcap_activate(3PCAP),
|
|
pcap_open_live(3PCAP)
|