*** UNIX MANUAL PAGE BROWSER ***

PCAP_FINDALLDEVS(3) Library Functions Manual PCAP_FINDALLDEVS(3) NAME pcap_findalldevs, pcap_freealldevs - get a list of capture devices, and free that list SYNOPSIS #include <pcap/pcap.h> char errbuf[PCAP_ERRBUF_SIZE]; int pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf); void pcap_freealldevs(pcap_if_t *alldevs); 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 does not have sufficient privileges to open them for capturing; if so, those devices will not appear on the list.) If pcap_findalldevs() suc- ceeds, the pointer pointed to by alldevsp is set to point to the first element of the list, or to NULL if no devices were found (this is con- sidered success). 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-read- able description of the device addresses a pointer to the first element of a list of network ad- dresses for the device, or NULL if the device has no ad- dresses flags device flags: PCAP_IF_LOOPBACK set if the device is a loopback interface PCAP_IF_UP set if the device is up PCAP_IF_RUNNING set if the device is running 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 device 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 device isn't a point-to-point interface Note that the addresses in the list of addresses might be IPv4 ad- dresses, IPv6 addresses, or some other type of addresses, so you must check the sa_family member of the 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 AF_INET, IPv6 addresses have the value AF_INET6 (which older operating systems that don't support IPv6 might not define), and other addresses have other values. Whether other addresses are re- turned, and what types they might have is platform-dependent. For IPv4 addresses, the struct sockaddr pointer can be interpreted as if it pointed to a struct sockaddr_in; for IPv6 addresses, it can be inter- preted as if it pointed to a struct sockaddr_in6. The list of devices must be freed with pcap_freealldevs(), which frees the list pointed to by alldevs. RETURN VALUE pcap_findalldevs() returns 0 on success and -1 on failure; as indi- cated, finding no devices is considered success, rather than failure, so 0 will be returned in that case. 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(3), pcap_create(3), pcap_activate(3), pcap_open_live(3) 10 January 2014 PCAP_FINDALLDEVS(3)