pfopen(3) Library Functions Manual pfopen(3)
Name
pfopen - open a packet filter file
Syntax
pfopen(ifname, flags)
char *ifname;
int flags;
Description
The packet filter (see ) provides raw access to Ethernets and similar network data link layers. The routine is used to open a packet fil-
ter file descriptor. The routine hides various details about the way packet filter files are opened and named.
The ifname argument is a pointer to a null-terminated string containing the name of the interface for which the application is opening the
packet filter. This name may be the name of an actual interface on the system (for example, ``de0'', ``qe2'') or it may be a pseudo-inter-
face name of the form ``pfn'', used to specify the nth interface attached to the system. For example, ``pf0'' specifies the first such
interface. If ifname is NULL, the default interface (``pf0'') is used.
The flags argument has the same meaning as the corresponding argument to the system call.
The file descriptor returned by is otherwise identical to one returned by
Diagnostics
The routine returns a negative integer if the file could not be opened. This may be because of resource limitations, or because the speci-
fied interface does not exist.
If there are a lot of packet filter applications in use, the routine might take a while.
See Also
open(2), packetfilter(4)
The Packet Filter: An Efficient Mechanism for User Level Network Code
pfopen(3)
