pfopen(3) [osf1 man page]

pfopen(3)						     Library Functions Manual							 pfopen(3)

NAME

       pfopen - Open a packet filter file

SYNOPSIS

       pfopen(ifname, flags)

       char *ifname; int flags;

DESCRIPTION

       The  packet filter (see packetfilter(7)) provides raw access to Ethernets and similar network data link layers.	The routine pfopen is used
       to open a packet filter 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, ln0) or it may be a pseudo-interface 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 open(2) system call.

       The file descriptor returned by pfopen is otherwise identical to one returned by open(2).

ERRORS

       The pfopen routine returns a negative integer if the file could not be opened.  This may be because of resource limitations, or because the
       specified interface does not exist.

RELATED INFORMATION

       Commands: open(2)

       Files: bpf(7), packetfilter(7) delim off

																	 pfopen(3)

PFLOG(4)						   BSD Kernel Interfaces Manual 						  PFLOG(4)

NAME

     pflog -- packet filter logging interface

SYNOPSIS

     device pflog

DESCRIPTION

     The pflog interface is a pseudo-device which makes visible all packets logged by the packet filter, pf(4).  Logged packets can easily be mon-
     itored in real time by invoking tcpdump(1) on the pflog interface, or stored to disk using pflogd(8).

     The pflog0 interface is created automatically at boot if both pf(4) and pflogd(8) are enabled; further instances can be created using
     ifconfig(8).

     Each packet retrieved on this interface has a header associated with it of length PFLOG_HDRLEN.  This header documents the address family,
     interface name, rule number, reason, action, and direction of the packet that was logged.	This structure, defined in <net/if_pflog.h> looks
     like

	   struct pfloghdr {
		   u_int8_t	   length;
		   sa_family_t	   af;
		   u_int8_t	   action;
		   u_int8_t	   reason;
		   char 	   ifname[IFNAMSIZ];
		   char 	   ruleset[PF_RULESET_NAME_SIZE];
		   u_int32_t	   rulenr;
		   u_int32_t	   subrulenr;
		   uid_t	   uid;
		   pid_t	   pid;
		   uid_t	   rule_uid;
		   pid_t	   rule_pid;
		   u_int8_t	   dir;
		   u_int8_t	   pad[3];
	   };

EXAMPLES

     Create a pflog interface and monitor all packets logged on it:

	   # ifconfig pflog1 up
	   # tcpdump -n -e -ttt -i pflog1

SEE ALSO

     tcpdump(1) inet(4), inet6(4), netintro(4), pf(4), ifconfig(8), pflogd(8)

HISTORY

     The pflog device first appeared in OpenBSD 3.0.

BSD
								 December 10, 2001							       BSD