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    The following form allows you to view linux man pages.

    Command:

    pf

    
    
    
    

    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 ser-
         vicing 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 hier-
         archies are laid out.  The final component of the anchor path is the
         anchor under which operations will be performed.
    
    
    

    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;
                         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 speci-
                 fied 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
                 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 ta-
                 ble.
    
         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.
    
                         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];
                         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
                 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 oper-
                 ation 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 fil-
                 ter.
    
                 struct pfioc_limit {
                         int             index;
                         unsigned        limit;
                 };
    
                 enum    { PF_LIMIT_STATES, PF_LIMIT_SRC_NODES, PF_LIMIT_FRAGS,
                           PF_LIMIT_TABLES, 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
                 };
                 #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 ele-
                 ments.  pfrio_esize must be the size of struct pfr_table.  On
                 exit, pfrio_nadd contains the number of tables effectively cre-
                 ated.
    
                 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 ele-
                 ments.  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];
    
                 addresses removed.
    
         DIOCRADDADDRS struct pfioc_table *io
                 Add one or more addresses to a table.  On entry, pfrio_table con-
                 tains 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 mem-
                 bers.
    
                 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 write-
                 able buffer for pfr_addr structures.  On exit, pfrio_size con-
                         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 ele-
                 ments 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 con-
                 tains 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
                 Atomically switch a vector of inactive rulesets to the active
                 rulesets.  This call is implemented as a standard two-phase com-
                 mit, which will either fail for all rulesets or completely suc-
                 ceed.  All tickets need to be valid.  This ioctl returns EBUSY if
                 another process is concurrently updating some of the same rule-
                 sets.
    
         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>
                 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 struc-
                 tures 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:
                         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.
    
    
    

    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[])
                 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), pfsync(4), pfctl(8), altq(9)
    
    
    

    HISTORY

         The pf packet filtering mechanism first appeared in OpenBSD 3.0.
    
    
    

    BSD February 7, 2005 BSD

    
    
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