pcap_lookupnet(3pcap) — Linux manual page

PCAP_LOOKUPNET(3PCAP)                               PCAP_LOOKUPNET(3PCAP)

NAME         top

       pcap_lookupnet - find the IPv4 network number and netmask for a
       device

SYNOPSIS         top

       #include <pcap/pcap.h>

       char errbuf[PCAP_ERRBUF_SIZE];

       int pcap_lookupnet(const char *device, bpf_u_int32 *netp,
           bpf_u_int32 *maskp, char *errbuf);

DESCRIPTION         top

       pcap_lookupnet() is used to determine the IPv4 network number and
       mask associated with the network device device.  Both netp and
       maskp are bpf_u_int32 pointers, on success both values will be set
       in network byte order.  errbuf is a buffer large enough to hold at
       least PCAP_ERRBUF_SIZE chars.

       This function is not available on Windows.  It supports neither
       IPv6 nor multiple IPv4 addresses per interface, which obviously is
       not practical in modern networks.  See pcap_findalldevs(3PCAP) for
       a more elaborate solution to the problem.

RETURN VALUE         top

       pcap_lookupnet() returns 0 on success and PCAP_ERROR on failure.
       If PCAP_ERROR is returned, errbuf is filled in with an appropriate
       error message.

SEE ALSO         top

       pcap(3PCAP)

COLOPHON         top

       This page is part of the libpcap (packet capture library) project.
       Information about the project can be found at 
       ⟨http://www.tcpdump.org/⟩.  If you have a bug report for this
       manual page, see ⟨http://www.tcpdump.org/#patches⟩.  This page was
       obtained from the project's upstream Git repository
       ⟨https://github.com/the-tcpdump-group/libpcap.git⟩ on 2025-02-02.
       (At that time, the date of the most recent commit that was found
       in the repository was 2025-01-31.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there is
       a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to
       man-pages@man7.org

                             31 January 2025        PCAP_LOOKUPNET(3PCAP)

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