path: root/share/man/man4/pf.4

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.Dd June 24, 2001
.Dt PF 4
.Os
.Sh NAME
.Nm pf
.Nd packet filter
.Sh SYNOPSIS
.Cd "pseudo-device pf 1"
.Sh DESCRIPTION
Packet filtering takes place in the kernel.
A pseudo-device, /dev/pf, allows userland processes to control the
behavior of the packet filter through an
.Xr ioctl 2
interface.
There are commands to enable and disable the filter, load rulesets,
add and remove individual rules or retrieve state table entries and
statistics.
The most commonly used functions are covered by
.Xr pfctl 8 .
.Pp
Manipulations like loading a ruleset that involve more than a single
ioctl call require a so-called ticket, which prevents the occurrence of
multiple concurrent manipulations.
.Pp
Fields of ioctl parameter structures that refer to packet data (like
addresses and ports) are generally expected in network byte-order.
.Sh FILES
.Bl -tag -width /dev/pf -compact
.It Pa /dev/pf
packet filtering device.
.El
.Sh IOCTL INTERFACE
pf supports the following
.Xr ioctl 2
commands:
.Bl -tag -width xxxxxx
.It Dv DIOCSTART
Starts the packet filter.
.It Dv DIOCSTOP
Stops the packet filter.
.It Dv DIOCSTARTALTQ
Starts the ALTQ bandwidth control system.
.It Dv DIOCSTOPALTQ
Stops the ALTQ bandwidth control system.
.It Dv DIOCBEGINADDRS  Fa "u_int32_t"
Clears the buffer address pool
and returns ticket for subsequent DIOCADDADDR, DIOCADDRULE and
DIOCCHANGERULE calls.
.It Dv DIOCADDADDR     Fa "struct pfioc_pooladdr"
.Bd -literal
struct pfioc_pooladdr {
	u_int32_t		action;
	u_int32_t		ticket;
	u_int32_t		nr;
	u_int32_t		r_num;
	u_int8_t		r_action;
	u_int8_t		r_last;
	u_int8_t		af;
	char			anchor[PF_ANCHOR_NAME_SIZE];
	char			ruleset[PF_RULESET_NAME_SIZE];
	struct pf_pooladdr	addr;
};
.Ed
.Pp
Adds pool address
.Va addr
to the buffer address pool to be used in the following
DIOCADDRULE or DIOCCHANGERULE call.
All other members of the structure are ignored.
.It Dv DIOCBEGINRULES  Fa "u_int32_t"
Clears the inactive ruleset for the type of rule indicated by
.Va rule.action
and returns ticket for subsequent
DIOCADDRULE and DIOCCOMMITRULES calls.
.It Dv DIOCADDRULE     Fa "struct pfioc_rule"
.Bd -literal
struct pfioc_rule {
	u_int32_t	action;
	u_int32_t	ticket;
	u_int32_t	pool_ticket;
	u_int32_t	nr;
	char		anchor[PF_ANCHOR_NAME_SIZE];
	char		ruleset[PF_RULESET_NAME_SIZE];
	struct pf_rule	rule;
};
.Ed
.Pp
Adds
.Va rule
at the end of the inactive ruleset.
Requires
.Va ticket
obtained through preceding DIOCBEGINRULES call, and
.Va pool_ticket
obtained through DIOCBEGINADDRS call.
DIOCADDADDR must also be called if any pool addresses are required.
The optional
.Va anchor
and
.Va ruleset
names indicate the anchor and ruleset in which to append the rule.
.Va nr
and
.Va action
are ignored.
.It Dv DIOCCOMMITRULES Fa "u_int32_t"
Switch inactive to active filter ruleset.
Requires
.Va ticket .
.It Dv DIOCBEGINALTQS  Fa "u_int32_t"
Clears the inactive list of queues and returns ticket for subsequent
DIOCADDALTQ and DIOCCOMMITALTQS calls.
.It Dv DIOCADDALTQ     Fa "struct pfioc_altq"
Adds
.Bd -literal
struct pfioc_altq {
	u_int32_t	ticket;
	u_int32_t	nr;
	struct pf_altq   altq;
};
.Ed
.It Dv DIOCCOMMITALTQS Fa "u_int32_t"
Switch inactive to active list of queues.
Requires
.Va ticket .
.It Dv DIOCGETRULES    Fa "struct pfioc_rule"
Returns
.Va ticket
for subsequent DIOCGETRULE calls and
.Va nr
of rules in the active ruleset.
.It Dv DIOCGETRULE     Fa "struct pfioc_rule"
Returns
.Va rule
number
.Va nr
using
.Va ticket
obtained through a preceding DIOCGETRULES call.
.It Dv DIOCGETADDRS    Fa "struct pfioc_pooladdr"
Returns
.Va ticket
for subsequent DIOCGETADDR calls and
.Va nr
of pool addresses in the rule specified with
.Va r_action ,
.Va r_num ,
.Va anchor
and
.Va ruleset .
.It Dv DIOCGETADDR     Fa "struct pfioc_pooladdr"
Returns pool address
.Va addr
number
.Va nr
from the rule specified with
.Va r_action ,
.Va r_num ,
.Va anchor
and
.Va ruleset
using
.Va ticket
obtained through a preceding DIOCGETADDRS call.
.It Dv DIOCGETALTQS    Fa "struct pfioc_altq"
Returns
.Va ticket
for subsequent DIOCGETALTQ calls and
.Va nr
of queues in the active list.
.It Dv DIOCGETALTQ     Fa "struct pfioc_altq"
Returns
.Va altq
number
.Va nr
using
.Va ticket
obtained through a preceding DIOCGETALTQS call.
.It Dv DIOCGETQSTATS   Fa "struct pfioc_qstats"
Returns statistics on a queue.
.Bd -literal
struct pfioc_qstats {
	u_int32_t	 ticket;
	u_int32_t	 nr;
	void		*buf;
	int		 nbytes;
	u_int8_t	 scheduler;
};
.Ed
.Pp
A pointer to a buffer of statistics
.Va buf
of length
.Va nbytes
for the queue specified by
.Va nr .
.It Dv DIOCCLRSTATES
Clears the state table.
.It Dv DIOCADDSTATE    Fa "struct pfioc_state"
Adds a state entry.
.It Dv DIOCGETSTATE    Fa "struct pfioc_state"
.Bd -literal
struct pfioc_state {
	u_int32_t	 nr;
	struct pf_state	 state;
};
.Ed
.Pp
Extracts the entry with the specified number from the state table.
.It Dv DIOCKILLSTATES  Fa "struct pfioc_state_kill"
Removes matching entries from the state table.
Returns the number of killed states in psk_af.
.Bd -literal
struct pfioc_state_kill {
	int			psk_af;
	int			psk_proto;
	struct pf_rule_addr	psk_src;
	struct pf_rule_addr	psk_dst;
};
.Ed
.It Dv DIOCSETSTATUSIF Fa "struct pfioc_if"
.Bd -literal
struct pfioc_if {
	char		 ifname[IFNAMSIZ];
};
.Ed
.Pp
Specifies the interface for which statistics are accumulated.
.It Dv DIOCGETSTATUS   Fa "struct pf_status"
.Bd -literal
struct pf_status {
	u_int64_t	 counters[PFRES_MAX];
	u_int64_t	 fcounters[FCNT_MAX];
	u_int64_t	 pcounters[2][2][3];
	u_int64_t	 bcounters[2][2];
	u_int32_t	 running;
	u_int32_t	 states;
	u_int32_t	 since;
	u_int32_t	 debug;
};
.Ed
.Pp
Gets the internal packet filter statistics.
.It Dv DIOCCLRSTATUS
Clears the internal packet filter statistics.
.It Dv DIOCNATLOOK     Fa "struct pfioc_natlook"
Looks up a state table entry by source and destination addresses and ports.
.Bd -literal
struct pfioc_natlook {
	struct pf_addr	 saddr;
	struct pf_addr	 daddr;
	struct pf_addr	 rsaddr;
	struct pf_addr	 rdaddr;
	u_int16_t	 sport;
	u_int16_t	 dport;
	u_int16_t	 rsport;
	u_int16_t	 rdport;
	u_int8_t	 af;
	u_int8_t	 proto;
	u_int8_t	 direction;
};
.Ed
.It Dv DIOCSETDEBUG    Fa "u_int32_t"
Sets the debug level.
.Bd -literal
enum	{ PF_DEBUG_NONE=0, PF_DEBUG_URGENT=1, PF_DEBUG_MISC=2 };
.Ed
.It Dv DIOCGETSTATES   Fa "struct pfioc_states"
.Bd -literal
struct pfioc_states {
	int	ps_len;
	union {
		caddr_t psu_buf;
		struct pf_state *psu_states;
	} ps_u;
#define ps_buf		ps_u.psu_buf
#define ps_states	ps_u.psu_states
};
.Ed
.It Dv DIOCCHANGERULE  Fa "struct pfioc_rule"
Adds or removes the
.Va rule
in the ruleset specified by
.Va rule.action .
.Bd -literal
enum	{ PF_CHANGE_ADD_HEAD=1, PF_CHANGE_ADD_TAIL=2,
	  PF_CHANGE_ADD_BEFORE=3, PF_CHANGE_ADD_AFTER=4,
	  PF_CHANGE_REMOVE=5, PF_CHANGE_GET_TICKET=6 };
.Ed
.Pp
The type of operation to be performed is indicated by
.Va action .
.Pp
.Va ticket
must be set to the value obtained with PF_CHANGE_GET_TICKET
for all actions except PF_CHANGE_GET_TICKET.
.Va pool_ticket
must be set to the value obtained with the DIOCBEGINADDRS call
for all actions except PF_CHANGE_REMOVE and PF_CHANGE_GET_TICKET.
.Pp
.Va anchor
and
.Va ruleset
indicate which anchor and ruleset the operation applies to.
.Va nr
indicates the rule number against which PF_CHANGE_ADD_BEFORE,
PF_CHANGE_ADD_AFTER or PF_CHANGE_REMOVE actions are applied.
.It Dv DIOCCHANGEADDR  Fa "struct pfioc_addr"
Adds or removes a pool address
.Va addr
from a rule specified with
.Va r_action ,
.Va r_num ,
.Va anchor
and
.Va ruleset .
.It Dv DIOCSETTIMEOUT  Fa "struct pfioc_tm"
.Bd -literal
struct pfioc_tm {
	int		 timeout;
	int		 seconds;
};
.Ed
.It Dv DIOCGETTIMEOUT  Fa "struct pfioc_tm"
.It Dv DIOCCLRRULECTRS
Clear per-rule statistics.
.It Dv DIOCSETLIMIT   Fa "struct pfioc_limit"
Sets hard limits on the memory pools used by the packet filter.
.Bd -literal
struct pfioc_limit {
	int		index;
	unsigned	limit;
};
.Ed
.It Dv DIOCGETLIMIT   Fa "struct pfioc_limit"
.El
.Sh EXAMPLES
The following example demonstrates how to use the DIOCNATLOOK command
to find the internal host/port of a NATed connection.
.Bd -literal
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <sys/fcntl.h>
#include <net/if.h>
#include <netinet/in.h>
#include <net/pfvar.h>
#include <stdio.h>

u_int32_t
read_address(const char *s)
{
	int a, b, c, d;

	sscanf(s, "%i.%i.%i.%i", &a, &b, &c, &d);
	return htonl(a << 24 | b << 16 | c << 8 | d);
}

void
print_address(u_int32_t a)
{
	a = ntohl(a);
	printf("%d.%d.%d.%d", a >> 24 & 255, a >> 16 & 255,
	    a >> 8 & 255, a & 255);
}

int
main(int argc, char *argv[])
{
	struct pfioc_natlook nl;
	int dev;

	if (argc != 5) {
		printf("%s <gwy addr> <gwy port> <ext addr> <ext port>\\n",
		    argv[0]);
		return 1;
	}

	dev = open("/dev/pf", O_RDWR);
	if (dev == -1)
		err(1, "open(\\"/dev/pf\\") failed");

	memset(&nl, 0, sizeof(struct pfioc_natlook));
	nl.saddr.v4.s_addr	= read_address(argv[1]);
	nl.sport		= htons(atoi(argv[2]));
	nl.daddr.v4.s_addr	= read_address(argv[3]);
	nl.dport		= htons(atoi(argv[4]));
	nl.af			= AF_INET;
	nl.proto		= IPPROTO_TCP;
	nl.direction		= PF_IN;

	if (ioctl(dev, DIOCNATLOOK, &nl))
		err(1, "DIOCNATLOOK");

	printf("internal host ");
	print_address(nl.rsaddr.v4.s_addr);
	printf(":%u\\n", ntohs(nl.rsport));
	return 0;
}
.Ed
.Sh SEE ALSO
.Xr bridge 4 ,
.Xr ioctl 2 ,
.Xr pflog 4 ,
.Xr pfsync 4 ,
.Xr pfctl 8
.Sh HISTORY
The
.Nm
packet filtering mechanism first appeared in
.Ox 3.0 .