GeezerVison is showing man.openbsd.org — pf(4) - OpenBSD manual pages
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).
Operations loading or reading a ruleset that involve
more than a single ioctl(2) call require a so-called
ticket, which
allows pf to deal with concurrent operations. For
certain ioctl(2) commands (currently DIOCGETRULES)
the number of tickets a program can get is limited. The programs must
explicitly release their tickets using the DIOCXEND
command to avoid hitting the limit. All tickets which are not freed by
DIOCXEND are released when the program closes
/dev/pf.
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. Anchor names with
characters after the terminating null byte are considered invalid; if used
in an ioctl, EINVAL will be returned.
pf supports the following
ioctl(2)
commands, available through
<net/pfvar.h>:
DIOCSTART- Start the packet filter.
DIOCSTOP- Stop the packet filter.
DIOCADDRULE
struct pfioc_rule *pr-
struct pfioc_rule {
u_int32_t action;
u_int32_t ticket;
u_int32_t nr;
char anchor[PATH_MAX];
char anchor_call[PATH_MAX];
struct pf_rule rule;
};
Add rule at the end of the inactive
ruleset. This call requires a ticket obtained
through a preceding DIOCXBEGIN call. The
optional anchor name indicates the anchor in which
to append the rule. nr and
action are ignored.
DIOCADDQUEUE
struct pfioc_queue *q- Add a queue.
struct pfioc_queue {
u_int32_t ticket;
u_int nr;
struct pf_queuespec queue;
};
DIOCGETRULES
struct pfioc_rule *pr- Get a ticket for subsequent
DIOCGETRULE calls and the number
nr of rules in the active ruleset. The ticket should
be released by the DIOCXEND command.
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.
DIOCGETQUEUES
struct pfioc_queue *pq- Get a ticket for subsequent
DIOCGETQUEUE calls and the number
nr of queues in the active list.
DIOCGETQUEUE
struct pfioc_queue *pq- Get the queueing discipline by its number nr using
the ticket obtained through a preceding
DIOCGETQUEUES call.
DIOCGETQSTATS
struct pfioc_qstats *pq- Get the statistics on a queue.
struct pfioc_qstats {
u_int32_t ticket;
u_int32_t nr;
struct pf_queuespec queue;
void *buf;
int nbytes;
};
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[PATH_MAX];
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;
u_int16_t psk_rdomain;
};
DIOCCLRSTATES
struct pfioc_state_kill *psk- Clear all states. It works like
DIOCKILLSTATES,
but ignores all fields of the pfioc_state_kill
structure, except psk_ifname.
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]; /* limit counters */
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_int64_t syncookies_inflight[2]; /* unACKed SYNcookies */
time_t since;
u_int32_t running;
u_int32_t states;
u_int32_t states_halfopen;
u_int32_t src_nodes;
u_int32_t debug;
u_int32_t hostid;
u_int32_t reass; /* reassembly */
u_int8_t syncookies_active;
u_int8_t syncookies_mode; /* never/always/adaptive */
u_int8_t pad[2];
char ifname[IFNAMSIZ];
u_int8_t pf_chksum[PF_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 rdomain;
u_int16_t rrdomain;
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;
};
This was primarily used to support transparent proxies with
rdr-to rules. New proxies should use divert-to rules instead. These do
not require access to the privileged /dev/pf
device and preserve the original destination address for
getsockname(2). For SOCK_DGRAM sockets,
the ip(4)
socket options IP_RECVDSTADDR and
IP_RECVDSTPORT can be used to retrieve the
destination address and port.
DIOCSETDEBUG
u_int32_t *level- Set the debug level. See the
syslog(3) man page for a list of valid debug levels.
DIOCGETSTATES
struct pfioc_states *ps- Get state table entries.
struct pfioc_states {
size_t ps_len;
union {
caddr_t psu_buf;
struct pfsync_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 pfsync_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.
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.
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.
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_TABLES, PF_LIMIT_TABLE_ENTRIES, PF_LIMIT_PKTDELAY_PKTS,
PF_LIMIT_ANCHORS, 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[PATH_MAX];
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;
time_t 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;
char pfra_ifname[IFNAMSIZ];
u_int32_t pfra_states;
u_int16_t pfra_weight;
u_int8_t pfra_af;
u_int8_t pfra_net;
u_int8_t pfra_not;
u_int8_t pfra_fback;
u_int8_t pfra_type;
u_int8_t pad[7];
};
#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];
time_t 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 type;
char anchor[PATH_MAX];
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 type, can
be one of 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.
DIOCXEND
u_int32_t *ticket- Release the ticket obtained by the
DIOCGETRULES
command.
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 fp_os;
pf_tcpopts_t fp_tcpopts; /* packed TCP options */
u_int16_t fp_wsize; /* TCP window size */
u_int16_t fp_psize; /* ip->ip_len */
u_int16_t fp_mss; /* TCP MSS */
u_int16_t fp_flags;
u_int8_t fp_optcnt; /* TCP option count */
u_int8_t fp_wscale; /* TCP window scaling */
u_int8_t fp_ttl; /* IPv4 TTL */
int fp_getnum; /* DIOCOSFPGET number */
};
struct pf_osfp_entry {
SLIST_ENTRY(pf_osfp_entry) fp_entry;
pf_osfp_t fp_os;
int fp_enflags;
#define PF_OSFP_EXPANDED 0x001 /* expanded entry */
#define PF_OSFP_GENERIC 0x002 /* generic signature */
#define PF_OSFP_NODETAIL 0x004 /* no p0f details */
#define PF_OSFP_LEN 32
u_char fp_class_nm[PF_OSFP_LEN];
u_char fp_version_nm[PF_OSFP_LEN];
u_char fp_subtype_nm[PF_OSFP_LEN];
};
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 {
size_t 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 groups 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 group.
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 {
char pfik_name[IFNAMSIZ];
RB_ENTRY(pfi_kif) pfik_tree;
u_int64_t pfik_packets[2][2][2];
u_int64_t pfik_bytes[2][2][2];
time_t pfik_tzero;
int pfik_flags;
int pfik_flags_new;
void *pfik_ah_cookie;
struct ifnet *pfik_ifp;
struct ifg_group *pfik_group;
int pfik_states;
int pfik_rules;
int pfik_routes;
int pfik_srcnodes;
int pfik_flagrefs;
TAILQ_HEAD(, pfi_dynaddr) pfik_dynaddrs;
};
DIOCSETSTATUSIF
struct pfioc_iface *pi- Specify the interface for which statistics are accumulated.
DIOCSETIFFLAG
struct pfioc_iface *io- Set the user settable 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_src_node_kill *psnk- Explicitly remove source tracking nodes.
struct pfioc_src_node_kill {
sa_family_t psnk_af;
struct pf_rule_addr psnk_src;
struct pf_rule_addr psnk_dst;
u_int psnk_killed;
};
- /dev/pf
- packet filtering device.
The following example demonstrates how to use the
DIOCGETLIMIT command to show the hard limit of a
memory pool used by the packet filter:
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <sys/fcntl.h>
#include <netinet/in.h>
#include <net/if.h>
#include <net/pfvar.h>
#include <err.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
static const struct {
const char *name;
int index;
} pf_limits[] = {
{ "states", PF_LIMIT_STATES },
{ "src-nodes", PF_LIMIT_SRC_NODES },
{ "frags", PF_LIMIT_FRAGS },
{ "tables", PF_LIMIT_TABLES },
{ "table-entries", PF_LIMIT_TABLE_ENTRIES },
{ "anchors", PF_LIMIT_ANCHORS },
{ NULL, 0 }
};
void
usage(void)
{
int i;
fprintf(stderr, "usage: %s [", getprogname());
for (i = 0; pf_limits[i].name; i++)
fprintf(stderr, "%s%s", (i > 0 ? "|" : ""), pf_limits[i].name);
fprintf(stderr, "]\n");
exit(1);
}
int
main(int argc, char *argv[])
{
struct pfioc_limit pl;
int i, dev;
int pool_index = -1;
if (argc != 2)
usage();
for (i = 0; pf_limits[i].name; i++)
if (strcmp(argv[1], pf_limits[i].name) == 0) {
pool_index = pf_limits[i].index;
break;
}
if (pool_index == -1) {
warnx("no such memory pool: %s", argv[1]);
usage();
}
dev = open("/dev/pf", O_RDWR);
if (dev == -1)
err(1, "open(\"/dev/pf\") failed");
memset(&pl, 0, sizeof(struct pfioc_limit));
pl.index = pool_index;
if (ioctl(dev, DIOCGETLIMIT, &pl) == -1)
err(1, "DIOCGETLIMIT");
printf("The %s memory pool has ", pf_limits[i].name);
if (pl.limit == UINT_MAX)
printf("unlimited entries.\n");
else
printf("a hard limit of %u entries.\n", pl.limit);
return 0;
}
The pf packet filtering mechanism first
appeared in OpenBSD 3.0.
|