1PCAP_FINDALLDEVS(3PCAP) PCAP_FINDALLDEVS(3PCAP)
2
6 pcap_findalldevs, pcap_freealldevs - get a list of capture devices, and
7 free that list
8
10 #include <pcap/pcap.h>
11 char errbuf[PCAP_ERRBUF_SIZE];
13 int pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf);
15 void pcap_freealldevs(pcap_if_t *alldevs);
16
18 pcap_findalldevs() constructs a list of network devices that can be
19 opened with pcap_create() and pcap_activate() or with pcap_open_live().
20 (Note that there may be network devices that cannot be opened by the
21 process calling pcap_findalldevs(), because, for example, that process
22 does not have sufficient privileges to open them for capturing; if so,
23 those devices will not appear on the list.) If pcap_findalldevs() suc‐
24 ceeds, the pointer pointed to by alldevsp is set to point to the first
25 element of the list, or to NULL if no devices were found (this is con‐
26 sidered success). Each element of the list is of type pcap_if_t, and
27 has the following members:
28 next if not NULL, a pointer to the next element in the list;
30 NULL for the last element of the list
31 name a pointer to a string giving a name for the device to
33 pass to pcap_open_live()
34 description
36 if not NULL, a pointer to a string giving a human-read‐
37 able description of the device
38 addresses
40 a pointer to the first element of a list of network
41 addresses for the device, or NULL if the device has no
42 addresses
43 flags device flags:
45 PCAP_IF_LOOPBACK
47 set if the device is a loopback interface
48 Each element of the list of addresses is of type pcap_addr_t, and has
50 the following members:
51 next if not NULL, a pointer to the next element in the list;
53 NULL for the last element of the list
54 addr a pointer to a struct sockaddr containing an address
56 netmask
58 if not NULL, a pointer to a struct sockaddr that contains
59 the netmask corresponding to the address pointed to by
60 addr
61 broadaddr
63 if not NULL, a pointer to a struct sockaddr that contains
64 the broadcast address corresponding to the address
65 pointed to by addr; may be null if the device doesn't
66 support broadcasts
67 dstaddr
69 if not NULL, a pointer to a struct sockaddr that contains
70 the destination address corresponding to the address
71 pointed to by addr; may be null if the device isn't a
72 point-to-point interface
73 Note that the addresses in the list of addresses might be IPv4
75 addresses, IPv6 addresses, or some other type of addresses, so you must
76 check the sa_family member of the struct sockaddr before interpreting
77 the contents of the address; do not assume that the addresses are all
78 IPv4 addresses, or even all IPv4 or IPv6 addresses. IPv4 addresses
79 have the value AF_INET, IPv6 addresses have the value AF_INET6 (which
80 older operating systems that don't support IPv6 might not define), and
81 other addresses have other values. Whether other addresses are
82 returned, and what types they might have is platform-dependent. For
83 IPv4 addresses, the struct sockaddr pointer can be interpreted as if it
84 pointed to a struct sockaddr_in; for IPv6 addresses, it can be inter‐
85 preted as if it pointed to a struct sockaddr_in6.
86 The list of devices must be freed with pcap_freealldevs(), whch frees
88 the list pointed to by alldevs.
89
91 pcap_findalldevs() returns 0 on success and -1 on failure; as indi‐
92 cated, finding no devices is considered success, rather than failure,
93 so 0 will be returned in that case. If -1 is returned, errbuf is
94 filled in with an appropriate error message. errbuf is assumed to be
95 able to hold at least PCAP_ERRBUF_SIZE chars.
96
98 pcap(3PCAP), pcap_create(3PCAP), pcap_activate(3PCAP),
99 pcap_open_live(3PCAP)
100 22 August 2010 PCAP_FINDALLDEVS(3PCAP)