The
pflog
interface is a device which makes visible all packets logged by
the packet filter,
pf(4).
Logged packets can easily be monitored in real
time by invoking
tcpdump(1)
on the
pflog
interface, or stored to disk using
pflogd(8).
The pflog0 interface is created when the
pflog
module is loaded;
further instances can be created using
ifconfig(8).
The
pflog
module is loaded automatically if both
pf(4)
and
pflogd(8)
are enabled.
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];
u_int32_t ridentifier;
};
