pf - packet filter
pseudo-device pf
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 byteorder.
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.
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.
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 {
u_int32_t nr;
struct pf_state state;
};
DIOCGETSTATE struct pfioc_state *ps
Extract the entry with the specified number nr 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_af.
struct pfioc_state_kill {
sa_family_t psk_af;
int psk_proto;
struct pf_rule_addr psk_src;
struct pf_rule_addr psk_dst;
char psk_ifname[IFNAMSIZ];
};
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 fcounters[FCNT_MAX];
u_int64_t scounters[SCNT_MAX];
u_int64_t pcounters[2][2][3];
u_int64_t bcounters[2][2];
u_int64_t stateid;
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];
};
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 zero, all states will be gathered into
pf_states and
ps_len will be set to the size they take in memory
(i.e.,
sizeof(struct pf_state) * nr). If ps_len is non-zero, as many
states that can fit into ps_len as possible will be
gathered, and
ps_len will be updated to the size those rules take
in memory.
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 };
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[pfrio_size]
contains a table of pfr_table structures. 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[pfrio_size]
contains a table of pfr_table structures. On exit,
pfrio_nadd
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[pfrio_size] contains a table of
pfr_table structures.
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[pfrio_size] contains the list
of pfr_addr structures to add. 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[pfrio_size]
contains the
list of pfr_addr structures to delete. 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[pfrio_size] contains the new list of
pfr_addr structures.
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[pfrio_size]
contains a table of pfr_addr structures to clear.
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[pfrio_size]
contains a
table of pfr_addr structures to test. On exit, the
kernel updates
the pfr_addr table 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[pfrio_size] contains a table
of pfr_table
structures, and pfrio_setflag contains the flags to
add, while
pfrio_clrflag contains 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 the list
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:
PF_RULESET_SCRUB Scrub (packet normalization)
rules.
PF_RULESET_FILTER Filter rules.
PF_RULESET_NAT NAT (Network Address Translation) rules.
PF_RULESET_BINAT Bidirectional NAT rules.
PF_RULESET_RDR Redirect rules.
PF_RULESET_ALTQ ALTQ disciplines.
PF_RULESET_TABLE Address tables.
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;
};
#define PFI_FLAG_GROUP 0x0001 /* gets groups of
interfaces */
#define PFI_FLAG_INSTANCE 0x0002 /* gets single
interfaces */
#define PFI_FLAG_ALLMASK 0x0003
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 represents the number of pfi_if 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_if). pfiio_flags should be set
to
PFI_FLAG_GROUP, PFI_FLAG_INSTANCE, or both, to tell
the kernel to
return a group of interfaces (drivers, like "fxp"),
real interface
instances (like "fxp1") or both. The data is
returned in
the pfi_if structure described below:
struct pfi_if {
char
pfif_name[IFNAMSIZ];
u_int64_t pfif_packets[2][2][2];
u_int64_t
pfif_bytes[2][2][2];
u_int64_t pfif_addcnt;
u_int64_t pfif_delcnt;
long pfif_tzero;
int
pfif_states;
int pfif_rules;
int pfif_flags;
};
#define PFI_IFLAG_GROUP 0x0001 /* group of
interfaces */
#define PFI_IFLAG_INSTANCE 0x0002 /* single
instance */
#define PFI_IFLAG_CLONABLE 0x0010 /* clonable
group */
#define PFI_IFLAG_DYNAMIC 0x0020 /* dynamic
group */
#define PFI_IFLAG_ATTACHED 0x0040 /* interface
attached */
DIOCICLRISTATS struct pfioc_iface *io
Clear the statistics counters of one or more interfaces.
pfiio_name and pfiio_flags can be used to select
which interfaces
need to be cleared. The filtering process is the
same as for
DIOCIGETIFACES. pfiio_nzero will be set by the kernel to the
number of interfaces and drivers that have been
cleared.
/dev/pf packet filtering device.
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>0,
argv[0]);
return 1;
}
dev = open("/dev/pf", O_RDWR);
if (dev == -1)
err(1, "open(
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(":%u0, ntohs(nl.rsport));
return 0;
}
ioctl(2), bridge(4), pflog(4), pfsync(4), pfctl(8), altq(9)
The pf packet filtering mechanism first appeared in OpenBSD
3.0.
OpenBSD 3.6 June 24, 2001
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