pf
Packet Filter pseudo-device
Name:
/dev/pfDescription:
Packet filtering takes place in io-pkt. A pseudo-device, /dev/pf, lets user processes control the behavior of the packet filter through an ioctl() interface. There are commands to enable and disable the filter, load rule sets, add and remove individual rules or state table entries, and retrieve statistics. The most commonly used functions are covered by pfctl.
Manipulations such as loading a rule set that involve more than a single ioctl() call require a ticket, which prevents the occurrence of multiple concurrent manipulations.
Fields of ioctl() parameter structures that refer to packet data (such as addresses and ports) are generally expected in network-byte order.
Rules and address tables are contained in anchors. When servicing an ioctl() request, if the anchor field of the argument structure is empty, io-pkt uses the default anchor (i.e., the main rule set) in operations. Anchors are specified by name and may be nested, with components separated by slashes, similar to the way that filesystem hierarchies are laid out. The final component of the anchor path is the anchor under which operations will be performed.
ioctl() interface
The pf pseudo-device supports the following ioctl() 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 in the NetBSD documentation).
DIOCSTOPALTQ- Stop the ALTQ bandwidth control system.
DIOCBEGINADDRS struct pfioc_pooladdr *pp- Clear the buffer address pool and get a ticket for subsequent
DIOCADDADDR,DIOCADDRULE, andDIOCCHANGERULEcalls. The pfioc_pooladdr structure is defined as follows: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; }; DIOCADDADDR struct pfioc_pooladdr *pp- Add the pool address, addr to the buffer address pool to be used
in the following
DIOCADDRULEorDIOCCHANGERULEcall. All other members of the structure are ignored. DIOCADDRULE struct pfioc_rule *pr- Add the given rule at the end of the inactive rule set.
The pfioc_rule structure is defined as follows:
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; };This call requires a ticket obtained through a preceding
DIOCXBEGINcall and a pool_ticket obtained through aDIOCBEGINADDRScall. You must also callDIOCADDADDRif any pool addresses are required.The optional anchor name indicates the anchor in which to append the rule. The nr and action members. are ignored.
DIOCADDALTQ struct pfioc_altq *pa- Add an ALTQ discipline or queue.
The pfioc_altq structure is defined as follows:
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
DIOCGETRULEcalls, and the number nr of rules in the active rule set. DIOCGETRULE struct pfioc_rule *pr- Get a rule by its number nr, using the ticket obtained
through a preceding
DIOCGETRULEScall.(QNX Neutrino 7.0 or later) If action is set to PF_GET_CLR_CNTR, the per-rule statistics for the requested rule are cleared.
DIOCGETADDRS struct pfioc_pooladdr *pp- Get a ticket for subsequent
DIOCGETADDRcalls 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
DIOCGETADDRScall. DIOCGETALTQS struct pfioc_altq *pa- Get a ticket for subsequent
DIOCGETALTQcalls 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
DIOCGETALTQScall. DIOCGETQSTATS struct pfioc_qstats *pq- Get the statistics for a queue.
The pfioc_qstats structure is defined as follows:
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- Get the number nr of rule sets (i.e., anchors) directly attached
to the anchor named by path for use in subsequent
DIOCGETRULESETcalls. The pfioc_ruleset structure is defined as follows:struct pfioc_ruleset { u_int32_t nr; char path[MAXPATHLEN]; char name[PF_ANCHOR_NAME_SIZE]; };Nested anchors, since they aren't directly attached to the given anchor, aren't included. This ioctl() command returns EINVAL if the given anchor doesn't exist.
DIOCGETRULESET struct pfioc_ruleset *pr- Get a rule set (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
DIOCGETRULESETScall. This ioctl() command returns EINVAL if the given anchor doesn't exist, or EBUSY if another process is concurrently updating a rule set. DIOCADDSTATE struct pfioc_state *ps- Add a state entry.
The pfioc_state structure is defined as follows:
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() command returns the number of killed states in psk_af.
The pfioc_state_kill structure is defined as follows:
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.
This command 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 to gather statistics.
The pfioc_if structure is defined as follows:
struct pfioc_if { char ifname[IFNAMSIZ]; }; DIOCGETSTATUS struct pf_status *s- Get the internal packet filter statistics.
The pf_status structure is defined as follows:
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_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.
The pfioc_natlook structure is defined as follows:
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 to one of PF_DEBUG_NONE, PF_DEBUG_URGENT, PF_DEBUG_MISC, or PF_DEBUG_NOISY.
DIOCGETSTATES struct pfioc_states *ps- Get state table entries.
The pfioc_states structure is defined as follows:
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 are gathered into pf_states, and ps_len is set to the size they take in memory (i.e.,
sizeof(struct pf_state) * nr). If ps_len is nonzero, as many states that can fit into ps_len as possible are gathered, and ps_len is updated to the size those rules take in memory. DIOCCHANGERULE struct pfioc_rule *pcr- Add or remove the rule in the rule set specified by rule.action.
The type of operation to be performed is indicated by action,
which can be any of the following:
- 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
You must set ticket to the value obtained with PF_CHANGE_GET_TICKET for all actions except PF_CHANGE_GET_TICKET. You must set pool_ticket to the value obtained with the
DIOCBEGINADDRScall for all actions except PF_CHANGE_REMOVE and PF_CHANGE_GET_TICKET. The anchor indicates which anchor the operation applies to. The nr member indicates the rule number against which to apply PF_CHANGE_ADD_BEFORE, PF_CHANGE_ADD_AFTER, or PF_CHANGE_REMOVE actions. 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- Set the state timeout of timeout to seconds.
The pfioc_tm structure is defined as follows:
struct pfioc_tm { int timeout; int seconds; };The old value is placed into seconds. For the possible values of timeout, see the PFTM_* values in <net/pfvar.h>.
DIOCGETTIMEOUT struct pfioc_tm *pt- Get the state timeout of timeout. The value is 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.
The pfioc_limit structure is defined as follows:
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 ioctl() commands that manipulate radix tables use the same structure described below.
On exit from the
DIOCRCLRTABLEScommand, pfrio_ndel contains the number of tables deleted. The pfioc_table structure is defined as follows: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.
The pfr_table structure is defined as follows:
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 a 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, io-pkt doesn't 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. The pfr_tstats structure is defined as follows: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.
The pfr_addr structure is defined as follows:
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 nonzero, pfrio_buffer[pfrio_size..pfrio_size2] must be a writeable buffer, into which io-pkt 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 io-pkt. If pfrio_size2 was set on entry, pfrio_size2 points to the size of the buffer used, exactly as for
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 is too small, io-pkt doesn't 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, io-pkt 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 io-pkt.
Note:You can delete tables if you remove the PFR_TFLAG_PERSIST flag of an unreferenced table.
DIOCRINADEFINE struct pfioc_table *io- Define 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. The pfrio_naddr member contains the number of addresses effectively put in the table.
DIOCXBEGIN struct pfioc_trans *io- Clear all the inactive rule sets specified in the pfioc_trans_e array.
The pfioc_trans structure is defined as follows:
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; };For each rule set, a ticket is returned for subsequent
add rule
ioctl() commands, as well as for theDIOCXCOMMITandDIOCXROLLBACKcalls.Rule set 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 rule sets to the active rule sets. This call is implemented as a standard two-phase commit, which either fails for all rule sets, or completely succeeds. All tickets need to be valid. This ioctl() command returns EBUSY if another process is concurrently updating some of the same rule sets.
DIOCXROLLBACK struct pfioc_trans *io- Clean up io-pkt by undoing all changes that have taken place
on the inactive rule sets since the last
DIOCXBEGIN.DIOCXROLLBACKsilently ignores rule sets for which the ticket is invalid. DIOCSETHOSTID u_int32_t *hostid- Set the host ID, which is used by pfsync to identify which host created state table entries.
DIOCOSFPFLUSH- Flush the passive OS fingerprint table.
DIOCOSFPADD struct pf_osfp_ioctl *io- Add a passive OS fingerprint to the table.
The pf_osfp_ioctl structure is defined as follows:
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; };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 patch level. 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 PF_OSFP_* definition in <net/pfvar.h>. 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.
This ioctl() command doesn't use the fp_getnum member.
Note:You must zero the structure's slack space for correct operation; memset() the whole structure to zero before filling and sending it to io-pkt. DIOCOSFPGET struct pf_osfp_ioctl *io- Get the passive OS fingerprint number fp_getnum from io-pkt's fingerprint list. The rest of the structure members comes back filled. Get the whole list by repeatedly incrementing the fp_getnum number until ioctl() gives an error of EBUSY.
DIOCGETSRCNODES struct pfioc_src_nodes *psn- Get the list of source nodes kept by sticky addresses and source tracking.
The pfioc_src_nodes structure is defined as follows:
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 };You must call ioctl() once with psn_len set to 0. If ioctl() returns without error, psn_len is set to the size of the buffer required to hold all the pf_src_node structures held in the table. You should then allocate a buffer of this size and place a pointer to this buffer in psn_buf. You must then call ioctl() again to fill this buffer with the actual source node data. After that call, psn_len is set to the length of the buffer actually used.
DIOCCLRSRCNODES- Clear the tree of source-tracking nodes.
DIOCIGETIFACES struct pfioc_iface *io- Get a list of interfaces and interface drivers known to pf.
All the ioctl() commands that manipulate interfaces use the 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 0x0003If it isn't empty, you can use pfiio_name to restrict the search to a specific interface or driver. The pfiio_buffer[pfiio_size] member 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 io-pkt manager replaces this value with the real number of entries it wants to return.
You should set pfiio_esize to
sizeof(struct pfi_if). You should set pfiio_flags to PFI_FLAG_GROUP, PFI_FLAG_INSTANCE, or both, to tell io-pkt to return a group of interfaces (drivers, such as fxp), real interface instances (e.g., 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.
You can use pfiio_name and pfiio_flags to select
which interfaces need to be cleared.
The filtering process is the same as for
DIOCIGETIFACES. The pfiio_nzero member is set by io-pkt to the number of interfaces and drivers that have been cleared. DIOCSETIFFLAG struct pfioc_iface *io- Set the user-setable flags of the pf internal interface description:
- PFI_IFLAG_SKIP — skip the interface.
The filtering process is the same as for
DIOCIGETIFACES. DIOCCLRIFFLAG struct pfioc_iface *io- Similar to
DIOCSETIFFLAG, but clear the flags.
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 <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;
}
Caveats:
The following functionality is missing from pf in this version of NetBSD:
- The
pfsyncprotocol isn't supported. - The
groupkeyword isn't supported.