NAME¶
pf
—
packet filter
SYNOPSIS¶
device pf
options PF_DEFAULT_TO_DROP
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
ioctl(2) interface. There are commands to enable
and disable the filter, load rulesets, add and remove individual rules or
state table entries, and retrieve statistics. The most commonly used functions
are covered by
pfctl(8).
Manipulations like loading a ruleset that involve more than a single
ioctl(2) call require a so-called
ticket, which prevents the occurrence of multiple
concurrent manipulations.
Fields of
ioctl(2) parameter structures that refer
to packet data (like addresses and ports) are generally expected in network
byte-order.
Rules and address tables are contained in so-called
anchors. When servicing an
ioctl(2) request, if the anchor field of the
argument structure is empty, the kernel will use the default anchor (i.e., the
main ruleset) in operations. Anchors are specified by name and may be nested,
with components separated by ‘/’ characters, similar to how file
system hierarchies are laid out. The final component of the anchor path is the
anchor under which operations will be performed.
SYSCTL VARIABLES AND LOADER TUNABLES¶
The following
loader(8) tunables are available.
- net.pf.states_hashsize
- Size of hash tables that store states. Should be power of 2. Default value
is 32768.
- net.pf.source_nodes_hashsize
- Size of hash table that store source nodes. Should be power of 2. Default
value is 8192.
Read only
sysctl(8) variables with matching names
are provided to obtain current values at runtime.
KERNEL OPTIONS¶
The following options in the kernel configuration file are related to
pf
operation:
PF_DEFAULT_TO_DROP
- Change default policy to drop by default
IOCTL INTERFACE¶
pf
supports the following
ioctl(2) commands, available through
⟨
net/pfvar.h⟩:
DIOCSTART
- Start the packet filter.
DIOCSTOP
- Stop the packet filter.
DIOCSTARTALTQ
- Start the ALTQ bandwidth control system (see
altq(9)).
DIOCSTOPALTQ
- Stop the ALTQ bandwidth control system.
DIOCBEGINADDRS
struct pfioc_pooladdr *pp
-
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[MAXPATHLEN];
struct pf_pooladdr addr;
};
Clear the buffer address pool and get a
ticket for subsequent
DIOCADDADDR
,
DIOCADDRULE
, and
DIOCCHANGERULE
calls.
DIOCADDADDR
struct pfioc_pooladdr *pp
-
Add the pool address addr to the buffer
address pool to be used in the following
DIOCADDRULE
or
DIOCCHANGERULE
call. All other members
of the structure are ignored.
DIOCADDRULE
struct pfioc_rule *pr
-
struct pfioc_rule {
u_int32_t action;
u_int32_t ticket;
u_int32_t pool_ticket;
u_int32_t nr;
char anchor[MAXPATHLEN];
char anchor_call[MAXPATHLEN];
struct pf_rule rule;
};
Add rule at the end of the inactive
ruleset. This call requires a ticket
obtained through a preceding DIOCXBEGIN
call and a pool_ticket obtained through a
DIOCBEGINADDRS
call.
DIOCADDADDR
must also be called if any
pool addresses are required. The optional
anchor name indicates the anchor in which
to append the rule. nr and
action are ignored.
DIOCADDALTQ
struct pfioc_altq *pa
- Add an ALTQ discipline or queue.
struct pfioc_altq {
u_int32_t action;
u_int32_t ticket;
u_int32_t nr;
struct pf_altq altq;
};
DIOCGETRULES
struct pfioc_rule *pr
- Get a ticket for subsequent
DIOCGETRULE
calls and the number
nr of rules in the active ruleset.
DIOCGETRULE
struct pfioc_rule *pr
- Get a rule by its number
nr using the
ticket obtained through a preceding
DIOCGETRULES
call. If
action is set to
PF_GET_CLR_CNTR
, the per-rule
statistics on the requested rule are cleared.
DIOCGETADDRS
struct pfioc_pooladdr *pp
- Get a ticket for subsequent
DIOCGETADDR
calls and the number
nr of pool addresses in the rule
specified with r_action,
r_num, and
anchor.
DIOCGETADDR
struct pfioc_pooladdr *pp
- Get the pool address addr by its number
nr from the rule specified with
r_action,
r_num, and
anchor using the
ticket obtained through a preceding
DIOCGETADDRS
call.
DIOCGETALTQS
struct pfioc_altq *pa
- Get a ticket for subsequent
DIOCGETALTQ
calls and the number
nr of queues in the active list.
DIOCGETALTQ
struct pfioc_altq *pa
- Get the queueing discipline altq by its
number nr using the
ticket obtained through a preceding
DIOCGETALTQS
call.
DIOCGETQSTATS
struct pfioc_qstats *pq
- Get the statistics on a queue.
struct pfioc_qstats {
u_int32_t ticket;
u_int32_t nr;
void *buf;
int nbytes;
u_int8_t scheduler;
};
This call fills in a pointer to the buffer of statistics
buf, of length
nbytes, for the queue specified by
nr.
DIOCGETRULESETS
struct pfioc_ruleset *pr
-
struct pfioc_ruleset {
u_int32_t nr;
char path[MAXPATHLEN];
char name[PF_ANCHOR_NAME_SIZE];
};
Get the number nr of rulesets (i.e.,
anchors) directly attached to the anchor named by
path for use in subsequent
DIOCGETRULESET
calls. Nested anchors,
since they are not directly attached to the given anchor, will not be
included. This ioctl returns EINVAL
if
the given anchor does not exist.
DIOCGETRULESET
struct pfioc_ruleset *pr
- Get a ruleset (i.e., an anchor) name by
its number nr from the given anchor
path, the maximum number of which can be
obtained from a preceding
DIOCGETRULESETS
call. This ioctl
returns EINVAL
if the given anchor does
not exist or EBUSY
if another process
is concurrently updating a ruleset.
DIOCADDSTATE
struct pfioc_state *ps
- Add a state entry.
struct pfioc_state {
struct pfsync_state state;
};
DIOCGETSTATE
struct pfioc_state *ps
- Extract the entry identified by the id
and creatorid fields of the
state structure from the state
table.
DIOCKILLSTATES
struct pfioc_state_kill *psk
- Remove matching entries from the state table. This ioctl returns the
number of killed states in psk_killed.
struct pfioc_state_kill {
struct pf_state_cmp psk_pfcmp;
sa_family_t psk_af;
int psk_proto;
struct pf_rule_addr psk_src;
struct pf_rule_addr psk_dst;
char psk_ifname[IFNAMSIZ];
char psk_label[PF_RULE_LABEL_SIZE];
u_int psk_killed;
};
DIOCCLRSTATES
struct pfioc_state_kill *psk
- Clear all states. It works like
DIOCKILLSTATES
, but ignores the
psk_af,
psk_proto,
psk_src, and
psk_dst fields of the
pfioc_state_kill structure.
DIOCSETSTATUSIF
struct pfioc_if *pi
- Specify the interface for which statistics are accumulated.
struct pfioc_if {
char ifname[IFNAMSIZ];
};
DIOCGETSTATUS
struct pf_status *s
- Get the internal packet filter statistics.
struct pf_status {
u_int64_t counters[PFRES_MAX];
u_int64_t lcounters[LCNT_MAX];
u_int64_t fcounters[FCNT_MAX];
u_int64_t scounters[SCNT_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 src_nodes;
u_int32_t since;
u_int32_t debug;
u_int32_t hostid;
char ifname[IFNAMSIZ];
u_int8_t pf_chksum[MD5_DIGEST_LENGTH];
};
DIOCCLRSTATUS
- Clear the internal packet filter statistics.
DIOCNATLOOK
struct pfioc_natlook *pnl
- Look up a state table entry by source and destination addresses and ports.
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;
sa_family_t af;
u_int8_t proto;
u_int8_t direction;
};
DIOCSETDEBUG
u_int32_t *level
- Set the debug level.
enum { PF_DEBUG_NONE, PF_DEBUG_URGENT, PF_DEBUG_MISC,
PF_DEBUG_NOISY };
DIOCGETSTATES
struct pfioc_states *ps
- Get state table entries.
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
};
If ps_len is non-zero on entry, as many
states as possible that can fit into this size will be copied into the
supplied buffer ps_states. On exit,
ps_len is always set to the total size
required to hold all state table entries (i.e., it is set to
sizeof(struct pf_state) * nr
).
DIOCCHANGERULE
struct pfioc_rule *pcr
- Add or remove the rule in the ruleset
specified by rule.action.
The type of operation to be performed is indicated by
action, which can be any of the
following:
enum { PF_CHANGE_NONE, PF_CHANGE_ADD_HEAD, PF_CHANGE_ADD_TAIL,
PF_CHANGE_ADD_BEFORE, PF_CHANGE_ADD_AFTER,
PF_CHANGE_REMOVE, PF_CHANGE_GET_TICKET };
ticket must be set to the value obtained
with PF_CHANGE_GET_TICKET
for all
actions except PF_CHANGE_GET_TICKET
.
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
.
anchor indicates to which anchor the
operation applies. nr indicates the rule
number against which
PF_CHANGE_ADD_BEFORE
,
PF_CHANGE_ADD_AFTER
, or
PF_CHANGE_REMOVE
actions are
applied.
DIOCCHANGEADDR
struct pfioc_pooladdr *pca
- Add or remove the pool address addr from
the rule specified by r_action,
r_num, and
anchor.
DIOCSETTIMEOUT
struct pfioc_tm *pt
-
struct pfioc_tm {
int timeout;
int seconds;
};
Set the state timeout of timeout to
seconds. The old value will be placed
into seconds. For possible values of
timeout, consult the
PFTM_*
values in
⟨net/pfvar.h⟩.
DIOCGETTIMEOUT
struct pfioc_tm *pt
- Get the state timeout of timeout. The
value will be placed into the seconds
field.
DIOCCLRRULECTRS
- Clear per-rule statistics.
DIOCSETLIMIT
struct pfioc_limit *pl
- Set the hard limits on the memory pools used by the packet filter.
struct pfioc_limit {
int index;
unsigned limit;
};
enum { PF_LIMIT_STATES, PF_LIMIT_SRC_NODES, PF_LIMIT_FRAGS,
PF_LIMIT_TABLE_ENTRIES, PF_LIMIT_MAX };
DIOCGETLIMIT
struct pfioc_limit *pl
- Get the hard limit for the memory pool
indicated by index.
DIOCRCLRTABLES
struct pfioc_table *io
- Clear all tables. All the ioctls that manipulate radix tables use the same
structure described below. For
DIOCRCLRTABLES
,
pfrio_ndel contains on exit the number of
tables deleted.
struct pfioc_table {
struct pfr_table pfrio_table;
void *pfrio_buffer;
int pfrio_esize;
int pfrio_size;
int pfrio_size2;
int pfrio_nadd;
int pfrio_ndel;
int pfrio_nchange;
int pfrio_flags;
u_int32_t pfrio_ticket;
};
#define pfrio_exists pfrio_nadd
#define pfrio_nzero pfrio_nadd
#define pfrio_nmatch pfrio_nadd
#define pfrio_naddr pfrio_size2
#define pfrio_setflag pfrio_size2
#define pfrio_clrflag pfrio_nadd
DIOCRADDTABLES
struct pfioc_table *io
- Create one or more tables. On entry,
pfrio_buffer must point to an array of
struct pfr_table containing at least
pfrio_size elements.
pfrio_esize must be the size of
struct pfr_table. On exit,
pfrio_nadd contains the number of tables
effectively created.
struct pfr_table {
char pfrt_anchor[MAXPATHLEN];
char pfrt_name[PF_TABLE_NAME_SIZE];
u_int32_t pfrt_flags;
u_int8_t pfrt_fback;
};
DIOCRDELTABLES
struct pfioc_table *io
- Delete one or more tables. On entry,
pfrio_buffer must point to an array of
struct pfr_table containing at least
pfrio_size elements.
pfrio_esize must be the size of
struct pfr_table. On exit,
pfrio_ndel contains the number of tables
effectively deleted.
DIOCRGETTABLES
struct pfioc_table *io
- Get the list of all tables. On entry,
pfrio_buffer[pfrio_size] contains a valid
writeable buffer for pfr_table
structures. On exit, pfrio_size contains
the number of tables written into the buffer. If the buffer is too small,
the kernel does not store anything but just returns the required buffer
size, without error.
DIOCRGETTSTATS
struct pfioc_table *io
- This call is like
DIOCRGETTABLES
but is
used to get an array of pfr_tstats
structures.
struct pfr_tstats {
struct pfr_table pfrts_t;
u_int64_t pfrts_packets
[PFR_DIR_MAX][PFR_OP_TABLE_MAX];
u_int64_t pfrts_bytes
[PFR_DIR_MAX][PFR_OP_TABLE_MAX];
u_int64_t pfrts_match;
u_int64_t pfrts_nomatch;
long pfrts_tzero;
int pfrts_cnt;
int pfrts_refcnt[PFR_REFCNT_MAX];
};
#define pfrts_name pfrts_t.pfrt_name
#define pfrts_flags pfrts_t.pfrt_flags
DIOCRCLRTSTATS
struct pfioc_table *io
- Clear the statistics of one or more tables. On entry,
pfrio_buffer must point to an array of
struct pfr_table containing at least
pfrio_size elements.
pfrio_esize must be the size of
struct pfr_table. On exit,
pfrio_nzero contains the number of tables
effectively cleared.
DIOCRCLRADDRS
struct pfioc_table *io
- Clear all addresses in a table. On entry,
pfrio_table contains the table to clear.
On exit, pfrio_ndel contains the number
of addresses removed.
DIOCRADDADDRS
struct pfioc_table *io
- Add one or more addresses to a table. On entry,
pfrio_table contains the table ID and
pfrio_buffer must point to an array of
struct pfr_addr containing at least
pfrio_size elements to add to the table.
pfrio_esize must be the size of
struct pfr_addr. On exit,
pfrio_nadd contains the number of
addresses effectively added.
struct pfr_addr {
union {
struct in_addr _pfra_ip4addr;
struct in6_addr _pfra_ip6addr;
} pfra_u;
u_int8_t pfra_af;
u_int8_t pfra_net;
u_int8_t pfra_not;
u_int8_t pfra_fback;
};
#define pfra_ip4addr pfra_u._pfra_ip4addr
#define pfra_ip6addr pfra_u._pfra_ip6addr
DIOCRDELADDRS
struct pfioc_table *io
- Delete one or more addresses from a table. On entry,
pfrio_table contains the table ID and
pfrio_buffer must point to an array of
struct pfr_addr containing at least
pfrio_size elements to delete from the
table. pfrio_esize must be the size of
struct pfr_addr. On exit,
pfrio_ndel contains the number of
addresses effectively deleted.
DIOCRSETADDRS
struct pfioc_table *io
- Replace the content of a table by a new address list. This is the most
complicated command, which uses all the structure members.
On entry, pfrio_table contains the table ID
and pfrio_buffer must point to an array
of struct pfr_addr containing at least
pfrio_size elements which become the new
contents of the table. pfrio_esize must
be the size of struct pfr_addr.
Additionally, if pfrio_size2 is non-zero,
pfrio_buffer[pfrio_size..pfrio_size2]
must be a writeable buffer, into which the kernel can copy the addresses
that have been deleted during the replace operation. On exit,
pfrio_ndel,
pfrio_nadd, and
pfrio_nchange contain the number of
addresses deleted, added, and changed by the kernel. If
pfrio_size2 was set on entry,
pfrio_size2 will point to the size of the
buffer used, exactly like
DIOCRGETADDRS
.
DIOCRGETADDRS
struct pfioc_table *io
- Get all the addresses of a table. On entry,
pfrio_table contains the table ID and
pfrio_buffer[pfrio_size] contains a valid
writeable buffer for pfr_addr structures.
On exit, pfrio_size contains the number
of addresses written into the buffer. If the buffer was too small, the
kernel does not store anything but just returns the required buffer size,
without returning an error.
DIOCRGETASTATS
struct pfioc_table *io
- This call is like
DIOCRGETADDRS
but is
used to get an array of pfr_astats
structures.
struct pfr_astats {
struct pfr_addr pfras_a;
u_int64_t pfras_packets
[PFR_DIR_MAX][PFR_OP_ADDR_MAX];
u_int64_t pfras_bytes
[PFR_DIR_MAX][PFR_OP_ADDR_MAX];
long pfras_tzero;
};
DIOCRCLRASTATS
struct pfioc_table *io
- Clear the statistics of one or more addresses. On entry,
pfrio_table contains the table ID and
pfrio_buffer must point to an array of
struct pfr_addr containing at least
pfrio_size elements to be cleared from
the table. pfrio_esize must be the size
of struct pfr_addr. On exit,
pfrio_nzero contains the number of
addresses effectively cleared.
DIOCRTSTADDRS
struct pfioc_table *io
- Test if the given addresses match a table. On entry,
pfrio_table contains the table ID and
pfrio_buffer must point to an array of
struct pfr_addr containing at least
pfrio_size elements, each of which will
be tested for a match in the table.
pfrio_esize must be the size of
struct pfr_addr. On exit, the kernel
updates the pfr_addr array by setting the
pfra_fback member appropriately.
DIOCRSETTFLAGS
struct pfioc_table *io
- Change the
PFR_TFLAG_CONST
or
PFR_TFLAG_PERSIST
flags of a table. On
entry, pfrio_buffer must point to an
array of struct pfr_table containing at
least pfrio_size elements.
pfrio_esize must be the size of
struct pfr_table.
pfrio_setflag must contain the flags to
add, while pfrio_clrflag must contain the
flags to remove. On exit, pfrio_nchange
and pfrio_ndel contain the number of
tables altered or deleted by the kernel. Yes, tables can be deleted if one
removes the PFR_TFLAG_PERSIST
flag of
an unreferenced table.
DIOCRINADEFINE
struct pfioc_table *io
- Defines a table in the inactive set. On entry,
pfrio_table contains the table ID and
pfrio_buffer[pfrio_size] contains an
array of pfr_addr structures to put in
the table. A valid ticket must also be supplied to
pfrio_ticket. On exit,
pfrio_nadd contains 0 if the table was
already defined in the inactive list or 1 if a new table has been created.
pfrio_naddr contains the number of
addresses effectively put in the table.
DIOCXBEGIN
struct pfioc_trans *io
-
struct pfioc_trans {
int size; /* number of elements */
int esize; /* size of each element in bytes */
struct pfioc_trans_e {
int rs_num;
char anchor[MAXPATHLEN];
u_int32_t ticket;
} *array;
};
Clear all the inactive rulesets specified in the
pfioc_trans_e array. For each ruleset, a
ticket is returned for subsequent "add rule" ioctls, as well as
for the DIOCXCOMMIT
and
DIOCXROLLBACK
calls.
Ruleset types, identified by rs_num,
include the following:
DIOCXCOMMIT
struct pfioc_trans *io
- Atomically switch a vector of inactive rulesets to the active rulesets.
This call is implemented as a standard two-phase commit, which will either
fail for all rulesets or completely succeed. All tickets need to be valid.
This ioctl returns
EBUSY
if another
process is concurrently updating some of the same rulesets.
DIOCXROLLBACK
struct pfioc_trans *io
- Clean up the kernel by undoing all changes that have taken place on the
inactive rulesets since the last
DIOCXBEGIN
.
DIOCXROLLBACK
will silently ignore
rulesets for which the ticket is invalid.
DIOCSETHOSTID
u_int32_t *hostid
- Set the host ID, which is used by pfsync(4)
to identify which host created state table entries.
DIOCOSFPFLUSH
- Flush the passive OS fingerprint table.
DIOCOSFPADD
struct pf_osfp_ioctl *io
-
struct pf_osfp_ioctl {
struct pf_osfp_entry {
SLIST_ENTRY(pf_osfp_entry) fp_entry;
pf_osfp_t fp_os;
char fp_class_nm[PF_OSFP_LEN];
char fp_version_nm[PF_OSFP_LEN];
char fp_subtype_nm[PF_OSFP_LEN];
} fp_os;
pf_tcpopts_t fp_tcpopts;
u_int16_t fp_wsize;
u_int16_t fp_psize;
u_int16_t fp_mss;
u_int16_t fp_flags;
u_int8_t fp_optcnt;
u_int8_t fp_wscale;
u_int8_t fp_ttl;
int fp_getnum;
};
Add a passive OS fingerprint to the table. Set
fp_os.fp_os to the packed fingerprint,
fp_os.fp_class_nm to the name of the
class (Linux, Windows, etc),
fp_os.fp_version_nm to the name of the
version (NT, 95, 98), and
fp_os.fp_subtype_nm to the name of the
subtype or patchlevel. The members
fp_mss,
fp_wsize,
fp_psize,
fp_ttl,
fp_optcnt, and
fp_wscale are set to the TCP MSS, the TCP
window size, the IP length, the IP TTL, the number of TCP options, and the
TCP window scaling constant of the TCP SYN packet, respectively.
The fp_flags member is filled according to
the ⟨net/pfvar.h⟩ include
file PF_OSFP_*
defines. The
fp_tcpopts member contains packed TCP
options. Each option uses
PF_OSFP_TCPOPT_BITS
bits in the packed
value. Options include any of
PF_OSFP_TCPOPT_NOP
,
PF_OSFP_TCPOPT_SACK
,
PF_OSFP_TCPOPT_WSCALE
,
PF_OSFP_TCPOPT_MSS
, or
PF_OSFP_TCPOPT_TS
.
The fp_getnum member is not used with this
ioctl.
The structure's slack space must be zeroed for correct operation;
memset(3) the whole structure to zero before
filling and sending to the kernel.
DIOCOSFPGET
struct pf_osfp_ioctl *io
- Get the passive OS fingerprint number
fp_getnum from the kernel's fingerprint
list. The rest of the structure members will come back filled. Get the
whole list by repeatedly incrementing the
fp_getnum number until the ioctl returns
EBUSY
.
DIOCGETSRCNODES
struct pfioc_src_nodes *psn
-
struct pfioc_src_nodes {
int psn_len;
union {
caddr_t psu_buf;
struct pf_src_node *psu_src_nodes;
} psn_u;
#define psn_buf psn_u.psu_buf
#define psn_src_nodes psn_u.psu_src_nodes
};
Get the list of source nodes kept by sticky addresses and source tracking.
The ioctl must be called once with
psn_len set to 0. If the ioctl returns
without error, psn_len will be set to the
size of the buffer required to hold all the
pf_src_node structures held in the table.
A buffer of this size should then be allocated, and a pointer to this
buffer placed in psn_buf. The ioctl must
then be called again to fill this buffer with the actual source node data.
After that call, psn_len will be set to
the length of the buffer actually used.
DIOCCLRSRCNODES
- Clear the tree of source tracking nodes.
DIOCIGETIFACES
struct pfioc_iface *io
- Get the list of interfaces and interface drivers known to
pf
. All the ioctls that manipulate
interfaces use the same structure described below:
struct pfioc_iface {
char pfiio_name[IFNAMSIZ];
void *pfiio_buffer;
int pfiio_esize;
int pfiio_size;
int pfiio_nzero;
int pfiio_flags;
};
If not empty, pfiio_name can be used to
restrict the search to a specific interface or driver.
pfiio_buffer[pfiio_size] is the
user-supplied buffer for returning the data. On entry,
pfiio_size contains the number of
pfi_kif entries that can fit into the
buffer. The kernel will replace this value by the real number of entries
it wants to return. pfiio_esize should be
set to sizeof(struct pfi_kif)
.
The data is returned in the pfi_kif
structure described below:
struct pfi_kif {
RB_ENTRY(pfi_kif) pfik_tree;
char pfik_name[IFNAMSIZ];
u_int64_t pfik_packets[2][2][2];
u_int64_t pfik_bytes[2][2][2];
u_int32_t pfik_tzero;
int pfik_flags;
struct pf_state_tree_lan_ext pfik_lan_ext;
struct pf_state_tree_ext_gwy pfik_ext_gwy;
TAILQ_ENTRY(pfi_kif) pfik_w_states;
void *pfik_ah_cookie;
struct ifnet *pfik_ifp;
struct ifg_group *pfik_group;
int pfik_states;
int pfik_rules;
TAILQ_HEAD(, pfi_dynaddr) pfik_dynaddrs;
};
DIOCSETIFFLAG
struct pfioc_iface *io
- Set the user setable flags (described above) of the
pf
internal interface description. The
filtering process is the same as for
DIOCIGETIFACES
.
#define PFI_IFLAG_SKIP 0x0100 /* skip filtering on interface */
DIOCCLRIFFLAG
struct pfioc_iface *io
- Works as
DIOCSETIFFLAG
above but clears
the flags.
DIOCKILLSRCNODES
struct pfioc_iface *io
- Explicitly remove source tracking nodes.
FILES¶
- /dev/pf
- packet filtering device.
EXAMPLES¶
The following example demonstrates how to use the
DIOCNATLOOK
command to find the internal
host/port of a NATed connection:
#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 <err.h>
#include <stdio.h>
#include <stdlib.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;
}
SEE ALSO¶
ioctl(2),
altq(4),
if_bridge(4),
pflog(4),
pflow(4),
pfsync(4),
pfctl(8),
altq(9)
HISTORY¶
The
pf
packet filtering mechanism first
appeared in
OpenBSD 3.0 and then
FreeBSD 5.2.
This implementation is derived from
OpenBSD 4.5. It has
been heavily modified to be capable of running in multithreaded
FreeBSD kernel and scale its performance on multiple
CPUs.