pcap_findalldevs(3) - Linux man page

Name

pcap_findalldevs - get a list of capture devices

Synopsis

#include <pcap/pcap.h>

char errbuf[PCAP_ERRBUF_SIZE];

int pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf);

Description

pcap_findalldevs() constructs a list of network devices that can be opened with pcap_create() and pcap_activate() or with pcap_open_live(). (Note that there may be network devices that cannot be opened by the process calling pcap_findalldevs(), because, for example, that process might not have sufficient privileges to open them for capturing; if so, those devices will not appear on the list.) alldevsp is set to point to the first element of the list; each element of the list is of type pcap_if_t, and has the following members:
next
if not NULL, a pointer to the next element in the list; NULL for the last element of the list
name
a pointer to a string giving a name for the device to pass to pcap_open_live()
description
if not NULL, a pointer to a string giving a human-readable description of the device
addresses
a pointer to the first element of a list of addresses for the interface
flags
interface flags:
PCAP_IF_LOOPBACK
set if the interface is a loopback interface

Each element of the list of addresses is of type pcap_addr_t, and has the following members:

next
if not NULL, a pointer to the next element in the list; NULL for the last element of the list
addr
a pointer to a struct sockaddr containing an address
netmask
if not NULL, a pointer to a struct sockaddr that contains the netmask corresponding to the address pointed to by addr
broadaddr
if not NULL, a pointer to a struct sockaddr that contains the broadcast address corresponding to the address pointed to by addr; may be null if the interface doesn't support broadcasts
dstaddr
if not NULL, a pointer to a struct sockaddr that contains the destination address corresponding to the address pointed to by addr;
may be null if the interface isn't a point-to-point interface

Note that not all the addresses in the list of addresses are necessarily IPv4 or IPv6 addresses - you must check the sa_family member of the struct sockaddr before interpreting the contents of the address.

The list of devices must be freed with pcap_freealldevs().

Return Value

pcap_findalldevs() returns 0 on success and -1 on failure. If -1 is returned, errbuf is filled in with an appropriate error message. errbuf is assumed to be able to hold at least PCAP_ERRBUF_SIZE chars.

See Also

pcap(3PCAP), pcap_create(3PCAP), pcap_activate(3PCAP), pcap_open_live(3PCAP), pcap_freealldevs(3PCAP)