657592fd65
Obtained from: Yandex LLC MFC after: 1 week
1609 lines
41 KiB
C
1609 lines
41 KiB
C
/*-
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* Copyright (c) 2002 Luigi Rizzo, Universita` di Pisa
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#define DEB(x)
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#define DDB(x) x
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/*
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* Dynamic rule support for ipfw
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*/
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#include "opt_ipfw.h"
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#include "opt_inet.h"
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#ifndef INET
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#error IPFIREWALL requires INET.
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#endif /* INET */
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#include "opt_inet6.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/malloc.h>
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#include <sys/mbuf.h>
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#include <sys/kernel.h>
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#include <sys/ktr.h>
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#include <sys/lock.h>
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#include <sys/rmlock.h>
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#include <sys/socket.h>
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#include <sys/sysctl.h>
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#include <sys/syslog.h>
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#include <net/ethernet.h> /* for ETHERTYPE_IP */
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#include <net/if.h>
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#include <net/if_var.h>
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#include <net/vnet.h>
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#include <netinet/in.h>
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#include <netinet/ip.h>
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#include <netinet/ip_var.h> /* ip_defttl */
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#include <netinet/ip_fw.h>
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#include <netinet/tcp_var.h>
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#include <netinet/udp.h>
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#include <netinet/ip6.h> /* IN6_ARE_ADDR_EQUAL */
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#ifdef INET6
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#include <netinet6/in6_var.h>
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#include <netinet6/ip6_var.h>
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#endif
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#include <netpfil/ipfw/ip_fw_private.h>
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#include <machine/in_cksum.h> /* XXX for in_cksum */
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#ifdef MAC
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#include <security/mac/mac_framework.h>
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#endif
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/*
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* Description of dynamic rules.
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*
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* Dynamic rules are stored in lists accessed through a hash table
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* (ipfw_dyn_v) whose size is curr_dyn_buckets. This value can
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* be modified through the sysctl variable dyn_buckets which is
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* updated when the table becomes empty.
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*
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* XXX currently there is only one list, ipfw_dyn.
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*
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* When a packet is received, its address fields are first masked
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* with the mask defined for the rule, then hashed, then matched
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* against the entries in the corresponding list.
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* Dynamic rules can be used for different purposes:
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* + stateful rules;
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* + enforcing limits on the number of sessions;
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* + in-kernel NAT (not implemented yet)
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*
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* The lifetime of dynamic rules is regulated by dyn_*_lifetime,
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* measured in seconds and depending on the flags.
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*
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* The total number of dynamic rules is equal to UMA zone items count.
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* The max number of dynamic rules is dyn_max. When we reach
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* the maximum number of rules we do not create anymore. This is
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* done to avoid consuming too much memory, but also too much
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* time when searching on each packet (ideally, we should try instead
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* to put a limit on the length of the list on each bucket...).
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*
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* Each dynamic rule holds a pointer to the parent ipfw rule so
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* we know what action to perform. Dynamic rules are removed when
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* the parent rule is deleted. This can be changed by dyn_keep_states
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* sysctl.
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*
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* There are some limitations with dynamic rules -- we do not
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* obey the 'randomized match', and we do not do multiple
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* passes through the firewall. XXX check the latter!!!
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*/
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struct ipfw_dyn_bucket {
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struct mtx mtx; /* Bucket protecting lock */
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ipfw_dyn_rule *head; /* Pointer to first rule */
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};
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/*
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* Static variables followed by global ones
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*/
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static VNET_DEFINE(struct ipfw_dyn_bucket *, ipfw_dyn_v);
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static VNET_DEFINE(u_int32_t, dyn_buckets_max);
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static VNET_DEFINE(u_int32_t, curr_dyn_buckets);
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static VNET_DEFINE(struct callout, ipfw_timeout);
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#define V_ipfw_dyn_v VNET(ipfw_dyn_v)
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#define V_dyn_buckets_max VNET(dyn_buckets_max)
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#define V_curr_dyn_buckets VNET(curr_dyn_buckets)
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#define V_ipfw_timeout VNET(ipfw_timeout)
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static VNET_DEFINE(uma_zone_t, ipfw_dyn_rule_zone);
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#define V_ipfw_dyn_rule_zone VNET(ipfw_dyn_rule_zone)
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#define IPFW_BUCK_LOCK_INIT(b) \
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mtx_init(&(b)->mtx, "IPFW dynamic bucket", NULL, MTX_DEF)
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#define IPFW_BUCK_LOCK_DESTROY(b) \
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mtx_destroy(&(b)->mtx)
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#define IPFW_BUCK_LOCK(i) mtx_lock(&V_ipfw_dyn_v[(i)].mtx)
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#define IPFW_BUCK_UNLOCK(i) mtx_unlock(&V_ipfw_dyn_v[(i)].mtx)
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#define IPFW_BUCK_ASSERT(i) mtx_assert(&V_ipfw_dyn_v[(i)].mtx, MA_OWNED)
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static VNET_DEFINE(int, dyn_keep_states);
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#define V_dyn_keep_states VNET(dyn_keep_states)
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/*
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* Timeouts for various events in handing dynamic rules.
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*/
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static VNET_DEFINE(u_int32_t, dyn_ack_lifetime);
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static VNET_DEFINE(u_int32_t, dyn_syn_lifetime);
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static VNET_DEFINE(u_int32_t, dyn_fin_lifetime);
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static VNET_DEFINE(u_int32_t, dyn_rst_lifetime);
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static VNET_DEFINE(u_int32_t, dyn_udp_lifetime);
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static VNET_DEFINE(u_int32_t, dyn_short_lifetime);
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#define V_dyn_ack_lifetime VNET(dyn_ack_lifetime)
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#define V_dyn_syn_lifetime VNET(dyn_syn_lifetime)
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#define V_dyn_fin_lifetime VNET(dyn_fin_lifetime)
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#define V_dyn_rst_lifetime VNET(dyn_rst_lifetime)
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#define V_dyn_udp_lifetime VNET(dyn_udp_lifetime)
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#define V_dyn_short_lifetime VNET(dyn_short_lifetime)
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/*
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* Keepalives are sent if dyn_keepalive is set. They are sent every
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* dyn_keepalive_period seconds, in the last dyn_keepalive_interval
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* seconds of lifetime of a rule.
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* dyn_rst_lifetime and dyn_fin_lifetime should be strictly lower
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* than dyn_keepalive_period.
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*/
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static VNET_DEFINE(u_int32_t, dyn_keepalive_interval);
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static VNET_DEFINE(u_int32_t, dyn_keepalive_period);
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static VNET_DEFINE(u_int32_t, dyn_keepalive);
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static VNET_DEFINE(time_t, dyn_keepalive_last);
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#define V_dyn_keepalive_interval VNET(dyn_keepalive_interval)
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#define V_dyn_keepalive_period VNET(dyn_keepalive_period)
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#define V_dyn_keepalive VNET(dyn_keepalive)
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#define V_dyn_keepalive_last VNET(dyn_keepalive_last)
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static VNET_DEFINE(u_int32_t, dyn_max); /* max # of dynamic rules */
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#define DYN_COUNT uma_zone_get_cur(V_ipfw_dyn_rule_zone)
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#define V_dyn_max VNET(dyn_max)
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/* for userspace, we emulate the uma_zone_counter with ipfw_dyn_count */
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static int ipfw_dyn_count; /* number of objects */
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#ifdef USERSPACE /* emulation of UMA object counters for userspace */
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#define uma_zone_get_cur(x) ipfw_dyn_count
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#endif /* USERSPACE */
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static int last_log; /* Log ratelimiting */
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static void ipfw_dyn_tick(void *vnetx);
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static void check_dyn_rules(struct ip_fw_chain *, ipfw_range_tlv *, int, int);
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#ifdef SYSCTL_NODE
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static int sysctl_ipfw_dyn_count(SYSCTL_HANDLER_ARGS);
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static int sysctl_ipfw_dyn_max(SYSCTL_HANDLER_ARGS);
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SYSBEGIN(f2)
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SYSCTL_DECL(_net_inet_ip_fw);
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SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_buckets,
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CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_buckets_max), 0,
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"Max number of dyn. buckets");
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SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, curr_dyn_buckets,
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CTLFLAG_VNET | CTLFLAG_RD, &VNET_NAME(curr_dyn_buckets), 0,
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"Current Number of dyn. buckets");
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SYSCTL_PROC(_net_inet_ip_fw, OID_AUTO, dyn_count,
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CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RD, 0, 0, sysctl_ipfw_dyn_count, "IU",
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"Number of dyn. rules");
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SYSCTL_PROC(_net_inet_ip_fw, OID_AUTO, dyn_max,
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CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW, 0, 0, sysctl_ipfw_dyn_max, "IU",
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"Max number of dyn. rules");
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SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_ack_lifetime,
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CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_ack_lifetime), 0,
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"Lifetime of dyn. rules for acks");
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SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_syn_lifetime,
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CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_syn_lifetime), 0,
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"Lifetime of dyn. rules for syn");
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SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_fin_lifetime,
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CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_fin_lifetime), 0,
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"Lifetime of dyn. rules for fin");
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SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_rst_lifetime,
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CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_rst_lifetime), 0,
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"Lifetime of dyn. rules for rst");
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SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_udp_lifetime,
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CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_udp_lifetime), 0,
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"Lifetime of dyn. rules for UDP");
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SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_short_lifetime,
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CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_short_lifetime), 0,
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"Lifetime of dyn. rules for other situations");
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SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_keepalive,
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CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_keepalive), 0,
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"Enable keepalives for dyn. rules");
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SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_keep_states,
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CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_keep_states), 0,
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"Do not flush dynamic states on rule deletion");
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SYSEND
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#endif /* SYSCTL_NODE */
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#ifdef INET6
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static __inline int
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hash_packet6(struct ipfw_flow_id *id)
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{
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u_int32_t i;
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i = (id->dst_ip6.__u6_addr.__u6_addr32[2]) ^
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(id->dst_ip6.__u6_addr.__u6_addr32[3]) ^
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(id->src_ip6.__u6_addr.__u6_addr32[2]) ^
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(id->src_ip6.__u6_addr.__u6_addr32[3]) ^
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(id->dst_port) ^ (id->src_port);
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return i;
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}
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#endif
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/*
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* IMPORTANT: the hash function for dynamic rules must be commutative
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* in source and destination (ip,port), because rules are bidirectional
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* and we want to find both in the same bucket.
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*/
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static __inline int
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hash_packet(struct ipfw_flow_id *id, int buckets)
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{
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u_int32_t i;
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#ifdef INET6
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if (IS_IP6_FLOW_ID(id))
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i = hash_packet6(id);
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else
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#endif /* INET6 */
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i = (id->dst_ip) ^ (id->src_ip) ^ (id->dst_port) ^ (id->src_port);
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i &= (buckets - 1);
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return i;
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}
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/**
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* Print customizable flow id description via log(9) facility.
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*/
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static void
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print_dyn_rule_flags(struct ipfw_flow_id *id, int dyn_type, int log_flags,
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char *prefix, char *postfix)
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{
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struct in_addr da;
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#ifdef INET6
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char src[INET6_ADDRSTRLEN], dst[INET6_ADDRSTRLEN];
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#else
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char src[INET_ADDRSTRLEN], dst[INET_ADDRSTRLEN];
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#endif
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#ifdef INET6
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if (IS_IP6_FLOW_ID(id)) {
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ip6_sprintf(src, &id->src_ip6);
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ip6_sprintf(dst, &id->dst_ip6);
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} else
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#endif
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{
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da.s_addr = htonl(id->src_ip);
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inet_ntop(AF_INET, &da, src, sizeof(src));
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da.s_addr = htonl(id->dst_ip);
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inet_ntop(AF_INET, &da, dst, sizeof(dst));
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}
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log(log_flags, "ipfw: %s type %d %s %d -> %s %d, %d %s\n",
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prefix, dyn_type, src, id->src_port, dst,
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id->dst_port, DYN_COUNT, postfix);
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}
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#define print_dyn_rule(id, dtype, prefix, postfix) \
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print_dyn_rule_flags(id, dtype, LOG_DEBUG, prefix, postfix)
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#define TIME_LEQ(a,b) ((int)((a)-(b)) <= 0)
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#define TIME_LE(a,b) ((int)((a)-(b)) < 0)
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/*
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* Lookup a dynamic rule, locked version.
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*/
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static ipfw_dyn_rule *
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lookup_dyn_rule_locked(struct ipfw_flow_id *pkt, int i, int *match_direction,
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struct tcphdr *tcp)
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{
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/*
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* Stateful ipfw extensions.
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* Lookup into dynamic session queue.
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*/
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#define MATCH_REVERSE 0
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#define MATCH_FORWARD 1
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#define MATCH_NONE 2
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#define MATCH_UNKNOWN 3
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int dir = MATCH_NONE;
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ipfw_dyn_rule *prev, *q = NULL;
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IPFW_BUCK_ASSERT(i);
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for (prev = NULL, q = V_ipfw_dyn_v[i].head; q; prev = q, q = q->next) {
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if (q->dyn_type == O_LIMIT_PARENT && q->count)
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continue;
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if (pkt->proto != q->id.proto || q->dyn_type == O_LIMIT_PARENT)
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continue;
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if (IS_IP6_FLOW_ID(pkt)) {
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if (IN6_ARE_ADDR_EQUAL(&pkt->src_ip6, &q->id.src_ip6) &&
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IN6_ARE_ADDR_EQUAL(&pkt->dst_ip6, &q->id.dst_ip6) &&
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pkt->src_port == q->id.src_port &&
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pkt->dst_port == q->id.dst_port) {
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dir = MATCH_FORWARD;
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break;
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}
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if (IN6_ARE_ADDR_EQUAL(&pkt->src_ip6, &q->id.dst_ip6) &&
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IN6_ARE_ADDR_EQUAL(&pkt->dst_ip6, &q->id.src_ip6) &&
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pkt->src_port == q->id.dst_port &&
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pkt->dst_port == q->id.src_port) {
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dir = MATCH_REVERSE;
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break;
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}
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} else {
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if (pkt->src_ip == q->id.src_ip &&
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pkt->dst_ip == q->id.dst_ip &&
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pkt->src_port == q->id.src_port &&
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pkt->dst_port == q->id.dst_port) {
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dir = MATCH_FORWARD;
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break;
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}
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if (pkt->src_ip == q->id.dst_ip &&
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pkt->dst_ip == q->id.src_ip &&
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pkt->src_port == q->id.dst_port &&
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pkt->dst_port == q->id.src_port) {
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dir = MATCH_REVERSE;
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break;
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}
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}
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}
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if (q == NULL)
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goto done; /* q = NULL, not found */
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if (prev != NULL) { /* found and not in front */
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prev->next = q->next;
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q->next = V_ipfw_dyn_v[i].head;
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V_ipfw_dyn_v[i].head = q;
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}
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if (pkt->proto == IPPROTO_TCP) { /* update state according to flags */
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uint32_t ack;
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u_char flags = pkt->_flags & (TH_FIN | TH_SYN | TH_RST);
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#define BOTH_SYN (TH_SYN | (TH_SYN << 8))
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#define BOTH_FIN (TH_FIN | (TH_FIN << 8))
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#define TCP_FLAGS (TH_FLAGS | (TH_FLAGS << 8))
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#define ACK_FWD 0x10000 /* fwd ack seen */
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#define ACK_REV 0x20000 /* rev ack seen */
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q->state |= (dir == MATCH_FORWARD) ? flags : (flags << 8);
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switch (q->state & TCP_FLAGS) {
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case TH_SYN: /* opening */
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q->expire = time_uptime + V_dyn_syn_lifetime;
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break;
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case BOTH_SYN: /* move to established */
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case BOTH_SYN | TH_FIN: /* one side tries to close */
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case BOTH_SYN | (TH_FIN << 8):
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#define _SEQ_GE(a,b) ((int)(a) - (int)(b) >= 0)
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if (tcp == NULL)
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break;
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ack = ntohl(tcp->th_ack);
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if (dir == MATCH_FORWARD) {
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if (q->ack_fwd == 0 ||
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_SEQ_GE(ack, q->ack_fwd)) {
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q->ack_fwd = ack;
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q->state |= ACK_FWD;
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}
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} else {
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if (q->ack_rev == 0 ||
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_SEQ_GE(ack, q->ack_rev)) {
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q->ack_rev = ack;
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q->state |= ACK_REV;
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}
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}
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if ((q->state & (ACK_FWD | ACK_REV)) ==
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(ACK_FWD | ACK_REV)) {
|
|
q->expire = time_uptime + V_dyn_ack_lifetime;
|
|
q->state &= ~(ACK_FWD | ACK_REV);
|
|
}
|
|
break;
|
|
|
|
case BOTH_SYN | BOTH_FIN: /* both sides closed */
|
|
if (V_dyn_fin_lifetime >= V_dyn_keepalive_period)
|
|
V_dyn_fin_lifetime = V_dyn_keepalive_period - 1;
|
|
q->expire = time_uptime + V_dyn_fin_lifetime;
|
|
break;
|
|
|
|
default:
|
|
#if 0
|
|
/*
|
|
* reset or some invalid combination, but can also
|
|
* occur if we use keep-state the wrong way.
|
|
*/
|
|
if ( (q->state & ((TH_RST << 8)|TH_RST)) == 0)
|
|
printf("invalid state: 0x%x\n", q->state);
|
|
#endif
|
|
if (V_dyn_rst_lifetime >= V_dyn_keepalive_period)
|
|
V_dyn_rst_lifetime = V_dyn_keepalive_period - 1;
|
|
q->expire = time_uptime + V_dyn_rst_lifetime;
|
|
break;
|
|
}
|
|
} else if (pkt->proto == IPPROTO_UDP) {
|
|
q->expire = time_uptime + V_dyn_udp_lifetime;
|
|
} else {
|
|
/* other protocols */
|
|
q->expire = time_uptime + V_dyn_short_lifetime;
|
|
}
|
|
done:
|
|
if (match_direction != NULL)
|
|
*match_direction = dir;
|
|
return (q);
|
|
}
|
|
|
|
ipfw_dyn_rule *
|
|
ipfw_lookup_dyn_rule(struct ipfw_flow_id *pkt, int *match_direction,
|
|
struct tcphdr *tcp)
|
|
{
|
|
ipfw_dyn_rule *q;
|
|
int i;
|
|
|
|
i = hash_packet(pkt, V_curr_dyn_buckets);
|
|
|
|
IPFW_BUCK_LOCK(i);
|
|
q = lookup_dyn_rule_locked(pkt, i, match_direction, tcp);
|
|
if (q == NULL)
|
|
IPFW_BUCK_UNLOCK(i);
|
|
/* NB: return table locked when q is not NULL */
|
|
return q;
|
|
}
|
|
|
|
/*
|
|
* Unlock bucket mtx
|
|
* @p - pointer to dynamic rule
|
|
*/
|
|
void
|
|
ipfw_dyn_unlock(ipfw_dyn_rule *q)
|
|
{
|
|
|
|
IPFW_BUCK_UNLOCK(q->bucket);
|
|
}
|
|
|
|
static int
|
|
resize_dynamic_table(struct ip_fw_chain *chain, int nbuckets)
|
|
{
|
|
int i, k, nbuckets_old;
|
|
ipfw_dyn_rule *q;
|
|
struct ipfw_dyn_bucket *dyn_v, *dyn_v_old;
|
|
|
|
/* Check if given number is power of 2 and less than 64k */
|
|
if ((nbuckets > 65536) || (!powerof2(nbuckets)))
|
|
return 1;
|
|
|
|
CTR3(KTR_NET, "%s: resize dynamic hash: %d -> %d", __func__,
|
|
V_curr_dyn_buckets, nbuckets);
|
|
|
|
/* Allocate and initialize new hash */
|
|
dyn_v = malloc(nbuckets * sizeof(*dyn_v), M_IPFW,
|
|
M_WAITOK | M_ZERO);
|
|
|
|
for (i = 0 ; i < nbuckets; i++)
|
|
IPFW_BUCK_LOCK_INIT(&dyn_v[i]);
|
|
|
|
/*
|
|
* Call upper half lock, as get_map() do to ease
|
|
* read-only access to dynamic rules hash from sysctl
|
|
*/
|
|
IPFW_UH_WLOCK(chain);
|
|
|
|
/*
|
|
* Acquire chain write lock to permit hash access
|
|
* for main traffic path without additional locks
|
|
*/
|
|
IPFW_WLOCK(chain);
|
|
|
|
/* Save old values */
|
|
nbuckets_old = V_curr_dyn_buckets;
|
|
dyn_v_old = V_ipfw_dyn_v;
|
|
|
|
/* Skip relinking if array is not set up */
|
|
if (V_ipfw_dyn_v == NULL)
|
|
V_curr_dyn_buckets = 0;
|
|
|
|
/* Re-link all dynamic states */
|
|
for (i = 0 ; i < V_curr_dyn_buckets ; i++) {
|
|
while (V_ipfw_dyn_v[i].head != NULL) {
|
|
/* Remove from current chain */
|
|
q = V_ipfw_dyn_v[i].head;
|
|
V_ipfw_dyn_v[i].head = q->next;
|
|
|
|
/* Get new hash value */
|
|
k = hash_packet(&q->id, nbuckets);
|
|
q->bucket = k;
|
|
/* Add to the new head */
|
|
q->next = dyn_v[k].head;
|
|
dyn_v[k].head = q;
|
|
}
|
|
}
|
|
|
|
/* Update current pointers/buckets values */
|
|
V_curr_dyn_buckets = nbuckets;
|
|
V_ipfw_dyn_v = dyn_v;
|
|
|
|
IPFW_WUNLOCK(chain);
|
|
|
|
IPFW_UH_WUNLOCK(chain);
|
|
|
|
/* Start periodic callout on initial creation */
|
|
if (dyn_v_old == NULL) {
|
|
callout_reset_on(&V_ipfw_timeout, hz, ipfw_dyn_tick, curvnet, 0);
|
|
return (0);
|
|
}
|
|
|
|
/* Destroy all mutexes */
|
|
for (i = 0 ; i < nbuckets_old ; i++)
|
|
IPFW_BUCK_LOCK_DESTROY(&dyn_v_old[i]);
|
|
|
|
/* Free old hash */
|
|
free(dyn_v_old, M_IPFW);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* Install state of type 'type' for a dynamic session.
|
|
* The hash table contains two type of rules:
|
|
* - regular rules (O_KEEP_STATE)
|
|
* - rules for sessions with limited number of sess per user
|
|
* (O_LIMIT). When they are created, the parent is
|
|
* increased by 1, and decreased on delete. In this case,
|
|
* the third parameter is the parent rule and not the chain.
|
|
* - "parent" rules for the above (O_LIMIT_PARENT).
|
|
*/
|
|
static ipfw_dyn_rule *
|
|
add_dyn_rule(struct ipfw_flow_id *id, int i, u_int8_t dyn_type, struct ip_fw *rule)
|
|
{
|
|
ipfw_dyn_rule *r;
|
|
|
|
IPFW_BUCK_ASSERT(i);
|
|
|
|
r = uma_zalloc(V_ipfw_dyn_rule_zone, M_NOWAIT | M_ZERO);
|
|
if (r == NULL) {
|
|
if (last_log != time_uptime) {
|
|
last_log = time_uptime;
|
|
log(LOG_DEBUG,
|
|
"ipfw: Cannot allocate dynamic state, "
|
|
"consider increasing net.inet.ip.fw.dyn_max\n");
|
|
}
|
|
return NULL;
|
|
}
|
|
ipfw_dyn_count++;
|
|
|
|
/*
|
|
* refcount on parent is already incremented, so
|
|
* it is safe to use parent unlocked.
|
|
*/
|
|
if (dyn_type == O_LIMIT) {
|
|
ipfw_dyn_rule *parent = (ipfw_dyn_rule *)rule;
|
|
if ( parent->dyn_type != O_LIMIT_PARENT)
|
|
panic("invalid parent");
|
|
r->parent = parent;
|
|
rule = parent->rule;
|
|
}
|
|
|
|
r->id = *id;
|
|
r->expire = time_uptime + V_dyn_syn_lifetime;
|
|
r->rule = rule;
|
|
r->dyn_type = dyn_type;
|
|
IPFW_ZERO_DYN_COUNTER(r);
|
|
r->count = 0;
|
|
|
|
r->bucket = i;
|
|
r->next = V_ipfw_dyn_v[i].head;
|
|
V_ipfw_dyn_v[i].head = r;
|
|
DEB(print_dyn_rule(id, dyn_type, "add dyn entry", "total");)
|
|
return r;
|
|
}
|
|
|
|
/**
|
|
* lookup dynamic parent rule using pkt and rule as search keys.
|
|
* If the lookup fails, then install one.
|
|
*/
|
|
static ipfw_dyn_rule *
|
|
lookup_dyn_parent(struct ipfw_flow_id *pkt, int *pindex, struct ip_fw *rule)
|
|
{
|
|
ipfw_dyn_rule *q;
|
|
int i, is_v6;
|
|
|
|
is_v6 = IS_IP6_FLOW_ID(pkt);
|
|
i = hash_packet( pkt, V_curr_dyn_buckets );
|
|
*pindex = i;
|
|
IPFW_BUCK_LOCK(i);
|
|
for (q = V_ipfw_dyn_v[i].head ; q != NULL ; q=q->next)
|
|
if (q->dyn_type == O_LIMIT_PARENT &&
|
|
rule== q->rule &&
|
|
pkt->proto == q->id.proto &&
|
|
pkt->src_port == q->id.src_port &&
|
|
pkt->dst_port == q->id.dst_port &&
|
|
(
|
|
(is_v6 &&
|
|
IN6_ARE_ADDR_EQUAL(&(pkt->src_ip6),
|
|
&(q->id.src_ip6)) &&
|
|
IN6_ARE_ADDR_EQUAL(&(pkt->dst_ip6),
|
|
&(q->id.dst_ip6))) ||
|
|
(!is_v6 &&
|
|
pkt->src_ip == q->id.src_ip &&
|
|
pkt->dst_ip == q->id.dst_ip)
|
|
)
|
|
) {
|
|
q->expire = time_uptime + V_dyn_short_lifetime;
|
|
DEB(print_dyn_rule(pkt, q->dyn_type,
|
|
"lookup_dyn_parent found", "");)
|
|
return q;
|
|
}
|
|
|
|
/* Add virtual limiting rule */
|
|
return add_dyn_rule(pkt, i, O_LIMIT_PARENT, rule);
|
|
}
|
|
|
|
/**
|
|
* Install dynamic state for rule type cmd->o.opcode
|
|
*
|
|
* Returns 1 (failure) if state is not installed because of errors or because
|
|
* session limitations are enforced.
|
|
*/
|
|
int
|
|
ipfw_install_state(struct ip_fw_chain *chain, struct ip_fw *rule,
|
|
ipfw_insn_limit *cmd, struct ip_fw_args *args, uint32_t tablearg)
|
|
{
|
|
ipfw_dyn_rule *q;
|
|
int i;
|
|
|
|
DEB(print_dyn_rule(&args->f_id, cmd->o.opcode, "install_state", "");)
|
|
|
|
i = hash_packet(&args->f_id, V_curr_dyn_buckets);
|
|
|
|
IPFW_BUCK_LOCK(i);
|
|
|
|
q = lookup_dyn_rule_locked(&args->f_id, i, NULL, NULL);
|
|
|
|
if (q != NULL) { /* should never occur */
|
|
DEB(
|
|
if (last_log != time_uptime) {
|
|
last_log = time_uptime;
|
|
printf("ipfw: %s: entry already present, done\n",
|
|
__func__);
|
|
})
|
|
IPFW_BUCK_UNLOCK(i);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* State limiting is done via uma(9) zone limiting.
|
|
* Save pointer to newly-installed rule and reject
|
|
* packet if add_dyn_rule() returned NULL.
|
|
* Note q is currently set to NULL.
|
|
*/
|
|
|
|
switch (cmd->o.opcode) {
|
|
case O_KEEP_STATE: /* bidir rule */
|
|
q = add_dyn_rule(&args->f_id, i, O_KEEP_STATE, rule);
|
|
break;
|
|
|
|
case O_LIMIT: { /* limit number of sessions */
|
|
struct ipfw_flow_id id;
|
|
ipfw_dyn_rule *parent;
|
|
uint32_t conn_limit;
|
|
uint16_t limit_mask = cmd->limit_mask;
|
|
int pindex;
|
|
|
|
conn_limit = IP_FW_ARG_TABLEARG(chain, cmd->conn_limit, limit);
|
|
|
|
DEB(
|
|
if (cmd->conn_limit == IP_FW_TARG)
|
|
printf("ipfw: %s: O_LIMIT rule, conn_limit: %u "
|
|
"(tablearg)\n", __func__, conn_limit);
|
|
else
|
|
printf("ipfw: %s: O_LIMIT rule, conn_limit: %u\n",
|
|
__func__, conn_limit);
|
|
)
|
|
|
|
id.dst_ip = id.src_ip = id.dst_port = id.src_port = 0;
|
|
id.proto = args->f_id.proto;
|
|
id.addr_type = args->f_id.addr_type;
|
|
id.fib = M_GETFIB(args->m);
|
|
|
|
if (IS_IP6_FLOW_ID (&(args->f_id))) {
|
|
bzero(&id.src_ip6, sizeof(id.src_ip6));
|
|
bzero(&id.dst_ip6, sizeof(id.dst_ip6));
|
|
|
|
if (limit_mask & DYN_SRC_ADDR)
|
|
id.src_ip6 = args->f_id.src_ip6;
|
|
if (limit_mask & DYN_DST_ADDR)
|
|
id.dst_ip6 = args->f_id.dst_ip6;
|
|
} else {
|
|
if (limit_mask & DYN_SRC_ADDR)
|
|
id.src_ip = args->f_id.src_ip;
|
|
if (limit_mask & DYN_DST_ADDR)
|
|
id.dst_ip = args->f_id.dst_ip;
|
|
}
|
|
if (limit_mask & DYN_SRC_PORT)
|
|
id.src_port = args->f_id.src_port;
|
|
if (limit_mask & DYN_DST_PORT)
|
|
id.dst_port = args->f_id.dst_port;
|
|
|
|
/*
|
|
* We have to release lock for previous bucket to
|
|
* avoid possible deadlock
|
|
*/
|
|
IPFW_BUCK_UNLOCK(i);
|
|
|
|
if ((parent = lookup_dyn_parent(&id, &pindex, rule)) == NULL) {
|
|
printf("ipfw: %s: add parent failed\n", __func__);
|
|
IPFW_BUCK_UNLOCK(pindex);
|
|
return (1);
|
|
}
|
|
|
|
if (parent->count >= conn_limit) {
|
|
if (V_fw_verbose && last_log != time_uptime) {
|
|
last_log = time_uptime;
|
|
char sbuf[24];
|
|
last_log = time_uptime;
|
|
snprintf(sbuf, sizeof(sbuf),
|
|
"%d drop session",
|
|
parent->rule->rulenum);
|
|
print_dyn_rule_flags(&args->f_id,
|
|
cmd->o.opcode,
|
|
LOG_SECURITY | LOG_DEBUG,
|
|
sbuf, "too many entries");
|
|
}
|
|
IPFW_BUCK_UNLOCK(pindex);
|
|
return (1);
|
|
}
|
|
/* Increment counter on parent */
|
|
parent->count++;
|
|
IPFW_BUCK_UNLOCK(pindex);
|
|
|
|
IPFW_BUCK_LOCK(i);
|
|
q = add_dyn_rule(&args->f_id, i, O_LIMIT, (struct ip_fw *)parent);
|
|
if (q == NULL) {
|
|
/* Decrement index and notify caller */
|
|
IPFW_BUCK_UNLOCK(i);
|
|
IPFW_BUCK_LOCK(pindex);
|
|
parent->count--;
|
|
IPFW_BUCK_UNLOCK(pindex);
|
|
return (1);
|
|
}
|
|
break;
|
|
}
|
|
default:
|
|
printf("ipfw: %s: unknown dynamic rule type %u\n",
|
|
__func__, cmd->o.opcode);
|
|
}
|
|
|
|
if (q == NULL) {
|
|
IPFW_BUCK_UNLOCK(i);
|
|
return (1); /* Notify caller about failure */
|
|
}
|
|
|
|
/* XXX just set lifetime */
|
|
lookup_dyn_rule_locked(&args->f_id, i, NULL, NULL);
|
|
|
|
IPFW_BUCK_UNLOCK(i);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Generate a TCP packet, containing either a RST or a keepalive.
|
|
* When flags & TH_RST, we are sending a RST packet, because of a
|
|
* "reset" action matched the packet.
|
|
* Otherwise we are sending a keepalive, and flags & TH_
|
|
* The 'replyto' mbuf is the mbuf being replied to, if any, and is required
|
|
* so that MAC can label the reply appropriately.
|
|
*/
|
|
struct mbuf *
|
|
ipfw_send_pkt(struct mbuf *replyto, struct ipfw_flow_id *id, u_int32_t seq,
|
|
u_int32_t ack, int flags)
|
|
{
|
|
struct mbuf *m = NULL; /* stupid compiler */
|
|
int len, dir;
|
|
struct ip *h = NULL; /* stupid compiler */
|
|
#ifdef INET6
|
|
struct ip6_hdr *h6 = NULL;
|
|
#endif
|
|
struct tcphdr *th = NULL;
|
|
|
|
MGETHDR(m, M_NOWAIT, MT_DATA);
|
|
if (m == NULL)
|
|
return (NULL);
|
|
|
|
M_SETFIB(m, id->fib);
|
|
#ifdef MAC
|
|
if (replyto != NULL)
|
|
mac_netinet_firewall_reply(replyto, m);
|
|
else
|
|
mac_netinet_firewall_send(m);
|
|
#else
|
|
(void)replyto; /* don't warn about unused arg */
|
|
#endif
|
|
|
|
switch (id->addr_type) {
|
|
case 4:
|
|
len = sizeof(struct ip) + sizeof(struct tcphdr);
|
|
break;
|
|
#ifdef INET6
|
|
case 6:
|
|
len = sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
|
|
break;
|
|
#endif
|
|
default:
|
|
/* XXX: log me?!? */
|
|
FREE_PKT(m);
|
|
return (NULL);
|
|
}
|
|
dir = ((flags & (TH_SYN | TH_RST)) == TH_SYN);
|
|
|
|
m->m_data += max_linkhdr;
|
|
m->m_flags |= M_SKIP_FIREWALL;
|
|
m->m_pkthdr.len = m->m_len = len;
|
|
m->m_pkthdr.rcvif = NULL;
|
|
bzero(m->m_data, len);
|
|
|
|
switch (id->addr_type) {
|
|
case 4:
|
|
h = mtod(m, struct ip *);
|
|
|
|
/* prepare for checksum */
|
|
h->ip_p = IPPROTO_TCP;
|
|
h->ip_len = htons(sizeof(struct tcphdr));
|
|
if (dir) {
|
|
h->ip_src.s_addr = htonl(id->src_ip);
|
|
h->ip_dst.s_addr = htonl(id->dst_ip);
|
|
} else {
|
|
h->ip_src.s_addr = htonl(id->dst_ip);
|
|
h->ip_dst.s_addr = htonl(id->src_ip);
|
|
}
|
|
|
|
th = (struct tcphdr *)(h + 1);
|
|
break;
|
|
#ifdef INET6
|
|
case 6:
|
|
h6 = mtod(m, struct ip6_hdr *);
|
|
|
|
/* prepare for checksum */
|
|
h6->ip6_nxt = IPPROTO_TCP;
|
|
h6->ip6_plen = htons(sizeof(struct tcphdr));
|
|
if (dir) {
|
|
h6->ip6_src = id->src_ip6;
|
|
h6->ip6_dst = id->dst_ip6;
|
|
} else {
|
|
h6->ip6_src = id->dst_ip6;
|
|
h6->ip6_dst = id->src_ip6;
|
|
}
|
|
|
|
th = (struct tcphdr *)(h6 + 1);
|
|
break;
|
|
#endif
|
|
}
|
|
|
|
if (dir) {
|
|
th->th_sport = htons(id->src_port);
|
|
th->th_dport = htons(id->dst_port);
|
|
} else {
|
|
th->th_sport = htons(id->dst_port);
|
|
th->th_dport = htons(id->src_port);
|
|
}
|
|
th->th_off = sizeof(struct tcphdr) >> 2;
|
|
|
|
if (flags & TH_RST) {
|
|
if (flags & TH_ACK) {
|
|
th->th_seq = htonl(ack);
|
|
th->th_flags = TH_RST;
|
|
} else {
|
|
if (flags & TH_SYN)
|
|
seq++;
|
|
th->th_ack = htonl(seq);
|
|
th->th_flags = TH_RST | TH_ACK;
|
|
}
|
|
} else {
|
|
/*
|
|
* Keepalive - use caller provided sequence numbers
|
|
*/
|
|
th->th_seq = htonl(seq);
|
|
th->th_ack = htonl(ack);
|
|
th->th_flags = TH_ACK;
|
|
}
|
|
|
|
switch (id->addr_type) {
|
|
case 4:
|
|
th->th_sum = in_cksum(m, len);
|
|
|
|
/* finish the ip header */
|
|
h->ip_v = 4;
|
|
h->ip_hl = sizeof(*h) >> 2;
|
|
h->ip_tos = IPTOS_LOWDELAY;
|
|
h->ip_off = htons(0);
|
|
h->ip_len = htons(len);
|
|
h->ip_ttl = V_ip_defttl;
|
|
h->ip_sum = 0;
|
|
break;
|
|
#ifdef INET6
|
|
case 6:
|
|
th->th_sum = in6_cksum(m, IPPROTO_TCP, sizeof(*h6),
|
|
sizeof(struct tcphdr));
|
|
|
|
/* finish the ip6 header */
|
|
h6->ip6_vfc |= IPV6_VERSION;
|
|
h6->ip6_hlim = IPV6_DEFHLIM;
|
|
break;
|
|
#endif
|
|
}
|
|
|
|
return (m);
|
|
}
|
|
|
|
/*
|
|
* Queue keepalive packets for given dynamic rule
|
|
*/
|
|
static struct mbuf **
|
|
ipfw_dyn_send_ka(struct mbuf **mtailp, ipfw_dyn_rule *q)
|
|
{
|
|
struct mbuf *m_rev, *m_fwd;
|
|
|
|
m_rev = (q->state & ACK_REV) ? NULL :
|
|
ipfw_send_pkt(NULL, &(q->id), q->ack_rev - 1, q->ack_fwd, TH_SYN);
|
|
m_fwd = (q->state & ACK_FWD) ? NULL :
|
|
ipfw_send_pkt(NULL, &(q->id), q->ack_fwd - 1, q->ack_rev, 0);
|
|
|
|
if (m_rev != NULL) {
|
|
*mtailp = m_rev;
|
|
mtailp = &(*mtailp)->m_nextpkt;
|
|
}
|
|
if (m_fwd != NULL) {
|
|
*mtailp = m_fwd;
|
|
mtailp = &(*mtailp)->m_nextpkt;
|
|
}
|
|
|
|
return (mtailp);
|
|
}
|
|
|
|
/*
|
|
* This procedure is used to perform various maintance
|
|
* on dynamic hash list. Currently it is called every second.
|
|
*/
|
|
static void
|
|
ipfw_dyn_tick(void * vnetx)
|
|
{
|
|
struct ip_fw_chain *chain;
|
|
int check_ka = 0;
|
|
#ifdef VIMAGE
|
|
struct vnet *vp = vnetx;
|
|
#endif
|
|
|
|
CURVNET_SET(vp);
|
|
|
|
chain = &V_layer3_chain;
|
|
|
|
/* Run keepalive checks every keepalive_period iff ka is enabled */
|
|
if ((V_dyn_keepalive_last + V_dyn_keepalive_period <= time_uptime) &&
|
|
(V_dyn_keepalive != 0)) {
|
|
V_dyn_keepalive_last = time_uptime;
|
|
check_ka = 1;
|
|
}
|
|
|
|
check_dyn_rules(chain, NULL, check_ka, 1);
|
|
|
|
callout_reset_on(&V_ipfw_timeout, hz, ipfw_dyn_tick, vnetx, 0);
|
|
|
|
CURVNET_RESTORE();
|
|
}
|
|
|
|
|
|
/*
|
|
* Walk thru all dynamic states doing generic maintance:
|
|
* 1) free expired states
|
|
* 2) free all states based on deleted rule / set
|
|
* 3) send keepalives for states if needed
|
|
*
|
|
* @chain - pointer to current ipfw rules chain
|
|
* @rule - delete all states originated by given rule if != NULL
|
|
* @set - delete all states originated by any rule in set @set if != RESVD_SET
|
|
* @check_ka - perform checking/sending keepalives
|
|
* @timer - indicate call from timer routine.
|
|
*
|
|
* Timer routine must call this function unlocked to permit
|
|
* sending keepalives/resizing table.
|
|
*
|
|
* Others has to call function with IPFW_UH_WLOCK held.
|
|
* Additionally, function assume that dynamic rule/set is
|
|
* ALREADY deleted so no new states can be generated by
|
|
* 'deleted' rules.
|
|
*
|
|
* Write lock is needed to ensure that unused parent rules
|
|
* are not freed by other instance (see stage 2, 3)
|
|
*/
|
|
static void
|
|
check_dyn_rules(struct ip_fw_chain *chain, ipfw_range_tlv *rt,
|
|
int check_ka, int timer)
|
|
{
|
|
struct mbuf *m0, *m, *mnext, **mtailp;
|
|
struct ip *h;
|
|
int i, dyn_count, new_buckets = 0, max_buckets;
|
|
int expired = 0, expired_limits = 0, parents = 0, total = 0;
|
|
ipfw_dyn_rule *q, *q_prev, *q_next;
|
|
ipfw_dyn_rule *exp_head, **exptailp;
|
|
ipfw_dyn_rule *exp_lhead, **expltailp;
|
|
|
|
KASSERT(V_ipfw_dyn_v != NULL, ("%s: dynamic table not allocated",
|
|
__func__));
|
|
|
|
/* Avoid possible LOR */
|
|
KASSERT(!check_ka || timer, ("%s: keepalive check with lock held",
|
|
__func__));
|
|
|
|
/*
|
|
* Do not perform any checks if we currently have no dynamic states
|
|
*/
|
|
if (DYN_COUNT == 0)
|
|
return;
|
|
|
|
/* Expired states */
|
|
exp_head = NULL;
|
|
exptailp = &exp_head;
|
|
|
|
/* Expired limit states */
|
|
exp_lhead = NULL;
|
|
expltailp = &exp_lhead;
|
|
|
|
/*
|
|
* We make a chain of packets to go out here -- not deferring
|
|
* until after we drop the IPFW dynamic rule lock would result
|
|
* in a lock order reversal with the normal packet input -> ipfw
|
|
* call stack.
|
|
*/
|
|
m0 = NULL;
|
|
mtailp = &m0;
|
|
|
|
/* Protect from hash resizing */
|
|
if (timer != 0)
|
|
IPFW_UH_WLOCK(chain);
|
|
else
|
|
IPFW_UH_WLOCK_ASSERT(chain);
|
|
|
|
#define NEXT_RULE() { q_prev = q; q = q->next ; continue; }
|
|
|
|
/* Stage 1: perform requested deletion */
|
|
for (i = 0 ; i < V_curr_dyn_buckets ; i++) {
|
|
IPFW_BUCK_LOCK(i);
|
|
for (q = V_ipfw_dyn_v[i].head, q_prev = q; q ; ) {
|
|
/* account every rule */
|
|
total++;
|
|
|
|
/* Skip parent rules at all */
|
|
if (q->dyn_type == O_LIMIT_PARENT) {
|
|
parents++;
|
|
NEXT_RULE();
|
|
}
|
|
|
|
/*
|
|
* Remove rules which are:
|
|
* 1) expired
|
|
* 2) matches deletion range
|
|
*/
|
|
if ((TIME_LEQ(q->expire, time_uptime)) ||
|
|
(rt != NULL && ipfw_match_range(q->rule, rt))) {
|
|
if (TIME_LE(time_uptime, q->expire) &&
|
|
q->dyn_type == O_KEEP_STATE &&
|
|
V_dyn_keep_states != 0) {
|
|
/*
|
|
* Do not delete state if
|
|
* it is not expired and
|
|
* dyn_keep_states is ON.
|
|
* However we need to re-link it
|
|
* to any other stable rule
|
|
*/
|
|
q->rule = chain->default_rule;
|
|
NEXT_RULE();
|
|
}
|
|
|
|
/* Unlink q from current list */
|
|
q_next = q->next;
|
|
if (q == V_ipfw_dyn_v[i].head)
|
|
V_ipfw_dyn_v[i].head = q_next;
|
|
else
|
|
q_prev->next = q_next;
|
|
|
|
q->next = NULL;
|
|
|
|
/* queue q to expire list */
|
|
if (q->dyn_type != O_LIMIT) {
|
|
*exptailp = q;
|
|
exptailp = &(*exptailp)->next;
|
|
DEB(print_dyn_rule(&q->id, q->dyn_type,
|
|
"unlink entry", "left");
|
|
)
|
|
} else {
|
|
/* Separate list for limit rules */
|
|
*expltailp = q;
|
|
expltailp = &(*expltailp)->next;
|
|
expired_limits++;
|
|
DEB(print_dyn_rule(&q->id, q->dyn_type,
|
|
"unlink limit entry", "left");
|
|
)
|
|
}
|
|
|
|
q = q_next;
|
|
expired++;
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* Check if we need to send keepalive:
|
|
* we need to ensure if is time to do KA,
|
|
* this is established TCP session, and
|
|
* expire time is within keepalive interval
|
|
*/
|
|
if ((check_ka != 0) && (q->id.proto == IPPROTO_TCP) &&
|
|
((q->state & BOTH_SYN) == BOTH_SYN) &&
|
|
(TIME_LEQ(q->expire, time_uptime +
|
|
V_dyn_keepalive_interval)))
|
|
mtailp = ipfw_dyn_send_ka(mtailp, q);
|
|
|
|
NEXT_RULE();
|
|
}
|
|
IPFW_BUCK_UNLOCK(i);
|
|
}
|
|
|
|
/* Stage 2: decrement counters from O_LIMIT parents */
|
|
if (expired_limits != 0) {
|
|
/*
|
|
* XXX: Note that deleting set with more than one
|
|
* heavily-used LIMIT rules can result in overwhelming
|
|
* locking due to lack of per-hash value sorting
|
|
*
|
|
* We should probably think about:
|
|
* 1) pre-allocating hash of size, say,
|
|
* MAX(16, V_curr_dyn_buckets / 1024)
|
|
* 2) checking if expired_limits is large enough
|
|
* 3) If yes, init hash (or its part), re-link
|
|
* current list and start decrementing procedure in
|
|
* each bucket separately
|
|
*/
|
|
|
|
/*
|
|
* Small optimization: do not unlock bucket until
|
|
* we see the next item resides in different bucket
|
|
*/
|
|
if (exp_lhead != NULL) {
|
|
i = exp_lhead->parent->bucket;
|
|
IPFW_BUCK_LOCK(i);
|
|
}
|
|
for (q = exp_lhead; q != NULL; q = q->next) {
|
|
if (i != q->parent->bucket) {
|
|
IPFW_BUCK_UNLOCK(i);
|
|
i = q->parent->bucket;
|
|
IPFW_BUCK_LOCK(i);
|
|
}
|
|
|
|
/* Decrease parent refcount */
|
|
q->parent->count--;
|
|
}
|
|
if (exp_lhead != NULL)
|
|
IPFW_BUCK_UNLOCK(i);
|
|
}
|
|
|
|
/*
|
|
* We protectet ourselves from unused parent deletion
|
|
* (from the timer function) by holding UH write lock.
|
|
*/
|
|
|
|
/* Stage 3: remove unused parent rules */
|
|
if ((parents != 0) && (expired != 0)) {
|
|
for (i = 0 ; i < V_curr_dyn_buckets ; i++) {
|
|
IPFW_BUCK_LOCK(i);
|
|
for (q = V_ipfw_dyn_v[i].head, q_prev = q ; q ; ) {
|
|
if (q->dyn_type != O_LIMIT_PARENT)
|
|
NEXT_RULE();
|
|
|
|
if (q->count != 0)
|
|
NEXT_RULE();
|
|
|
|
/* Parent rule without consumers */
|
|
|
|
/* Unlink q from current list */
|
|
q_next = q->next;
|
|
if (q == V_ipfw_dyn_v[i].head)
|
|
V_ipfw_dyn_v[i].head = q_next;
|
|
else
|
|
q_prev->next = q_next;
|
|
|
|
q->next = NULL;
|
|
|
|
/* Add to expired list */
|
|
*exptailp = q;
|
|
exptailp = &(*exptailp)->next;
|
|
|
|
DEB(print_dyn_rule(&q->id, q->dyn_type,
|
|
"unlink parent entry", "left");
|
|
)
|
|
|
|
expired++;
|
|
|
|
q = q_next;
|
|
}
|
|
IPFW_BUCK_UNLOCK(i);
|
|
}
|
|
}
|
|
|
|
#undef NEXT_RULE
|
|
|
|
if (timer != 0) {
|
|
/*
|
|
* Check if we need to resize hash:
|
|
* if current number of states exceeds number of buckes in hash,
|
|
* grow hash size to the minimum power of 2 which is bigger than
|
|
* current states count. Limit hash size by 64k.
|
|
*/
|
|
max_buckets = (V_dyn_buckets_max > 65536) ?
|
|
65536 : V_dyn_buckets_max;
|
|
|
|
dyn_count = DYN_COUNT;
|
|
|
|
if ((dyn_count > V_curr_dyn_buckets * 2) &&
|
|
(dyn_count < max_buckets)) {
|
|
new_buckets = V_curr_dyn_buckets;
|
|
while (new_buckets < dyn_count) {
|
|
new_buckets *= 2;
|
|
|
|
if (new_buckets >= max_buckets)
|
|
break;
|
|
}
|
|
}
|
|
|
|
IPFW_UH_WUNLOCK(chain);
|
|
}
|
|
|
|
/* Finally delete old states ad limits if any */
|
|
for (q = exp_head; q != NULL; q = q_next) {
|
|
q_next = q->next;
|
|
uma_zfree(V_ipfw_dyn_rule_zone, q);
|
|
ipfw_dyn_count--;
|
|
}
|
|
|
|
for (q = exp_lhead; q != NULL; q = q_next) {
|
|
q_next = q->next;
|
|
uma_zfree(V_ipfw_dyn_rule_zone, q);
|
|
ipfw_dyn_count--;
|
|
}
|
|
|
|
/*
|
|
* The rest code MUST be called from timer routine only
|
|
* without holding any locks
|
|
*/
|
|
if (timer == 0)
|
|
return;
|
|
|
|
/* Send keepalive packets if any */
|
|
for (m = m0; m != NULL; m = mnext) {
|
|
mnext = m->m_nextpkt;
|
|
m->m_nextpkt = NULL;
|
|
h = mtod(m, struct ip *);
|
|
if (h->ip_v == 4)
|
|
ip_output(m, NULL, NULL, 0, NULL, NULL);
|
|
#ifdef INET6
|
|
else
|
|
ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL);
|
|
#endif
|
|
}
|
|
|
|
/* Run table resize without holding any locks */
|
|
if (new_buckets != 0)
|
|
resize_dynamic_table(chain, new_buckets);
|
|
}
|
|
|
|
/*
|
|
* Deletes all dynamic rules originated by given rule or all rules in
|
|
* given set. Specify RESVD_SET to indicate set should not be used.
|
|
* @chain - pointer to current ipfw rules chain
|
|
* @rr - delete all states originated by rules in matched range.
|
|
*
|
|
* Function has to be called with IPFW_UH_WLOCK held.
|
|
* Additionally, function assume that dynamic rule/set is
|
|
* ALREADY deleted so no new states can be generated by
|
|
* 'deleted' rules.
|
|
*/
|
|
void
|
|
ipfw_expire_dyn_rules(struct ip_fw_chain *chain, ipfw_range_tlv *rt)
|
|
{
|
|
|
|
check_dyn_rules(chain, rt, 0, 0);
|
|
}
|
|
|
|
/*
|
|
* Check if rule contains at least one dynamic opcode.
|
|
*
|
|
* Returns 1 if such opcode is found, 0 otherwise.
|
|
*/
|
|
int
|
|
ipfw_is_dyn_rule(struct ip_fw *rule)
|
|
{
|
|
int cmdlen, l;
|
|
ipfw_insn *cmd;
|
|
|
|
l = rule->cmd_len;
|
|
cmd = rule->cmd;
|
|
cmdlen = 0;
|
|
for ( ; l > 0 ; l -= cmdlen, cmd += cmdlen) {
|
|
cmdlen = F_LEN(cmd);
|
|
|
|
switch (cmd->opcode) {
|
|
case O_LIMIT:
|
|
case O_KEEP_STATE:
|
|
case O_PROBE_STATE:
|
|
case O_CHECK_STATE:
|
|
return (1);
|
|
}
|
|
}
|
|
|
|
return (0);
|
|
}
|
|
|
|
void
|
|
ipfw_dyn_init(struct ip_fw_chain *chain)
|
|
{
|
|
|
|
V_ipfw_dyn_v = NULL;
|
|
V_dyn_buckets_max = 256; /* must be power of 2 */
|
|
V_curr_dyn_buckets = 256; /* must be power of 2 */
|
|
|
|
V_dyn_ack_lifetime = 300;
|
|
V_dyn_syn_lifetime = 20;
|
|
V_dyn_fin_lifetime = 1;
|
|
V_dyn_rst_lifetime = 1;
|
|
V_dyn_udp_lifetime = 10;
|
|
V_dyn_short_lifetime = 5;
|
|
|
|
V_dyn_keepalive_interval = 20;
|
|
V_dyn_keepalive_period = 5;
|
|
V_dyn_keepalive = 1; /* do send keepalives */
|
|
V_dyn_keepalive_last = time_uptime;
|
|
|
|
V_dyn_max = 16384; /* max # of dynamic rules */
|
|
|
|
V_ipfw_dyn_rule_zone = uma_zcreate("IPFW dynamic rule",
|
|
sizeof(ipfw_dyn_rule), NULL, NULL, NULL, NULL,
|
|
UMA_ALIGN_PTR, 0);
|
|
|
|
/* Enforce limit on dynamic rules */
|
|
uma_zone_set_max(V_ipfw_dyn_rule_zone, V_dyn_max);
|
|
|
|
callout_init(&V_ipfw_timeout, 1);
|
|
|
|
/*
|
|
* This can potentially be done on first dynamic rule
|
|
* being added to chain.
|
|
*/
|
|
resize_dynamic_table(chain, V_curr_dyn_buckets);
|
|
}
|
|
|
|
void
|
|
ipfw_dyn_uninit(int pass)
|
|
{
|
|
int i;
|
|
|
|
if (pass == 0) {
|
|
callout_drain(&V_ipfw_timeout);
|
|
return;
|
|
}
|
|
|
|
if (V_ipfw_dyn_v != NULL) {
|
|
/*
|
|
* Skip deleting all dynamic states -
|
|
* uma_zdestroy() does this more efficiently;
|
|
*/
|
|
|
|
/* Destroy all mutexes */
|
|
for (i = 0 ; i < V_curr_dyn_buckets ; i++)
|
|
IPFW_BUCK_LOCK_DESTROY(&V_ipfw_dyn_v[i]);
|
|
free(V_ipfw_dyn_v, M_IPFW);
|
|
V_ipfw_dyn_v = NULL;
|
|
}
|
|
|
|
uma_zdestroy(V_ipfw_dyn_rule_zone);
|
|
}
|
|
|
|
#ifdef SYSCTL_NODE
|
|
/*
|
|
* Get/set maximum number of dynamic states in given VNET instance.
|
|
*/
|
|
static int
|
|
sysctl_ipfw_dyn_max(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
int error;
|
|
unsigned int nstates;
|
|
|
|
nstates = V_dyn_max;
|
|
|
|
error = sysctl_handle_int(oidp, &nstates, 0, req);
|
|
/* Read operation or some error */
|
|
if ((error != 0) || (req->newptr == NULL))
|
|
return (error);
|
|
|
|
V_dyn_max = nstates;
|
|
uma_zone_set_max(V_ipfw_dyn_rule_zone, V_dyn_max);
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Get current number of dynamic states in given VNET instance.
|
|
*/
|
|
static int
|
|
sysctl_ipfw_dyn_count(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
int error;
|
|
unsigned int nstates;
|
|
|
|
nstates = DYN_COUNT;
|
|
|
|
error = sysctl_handle_int(oidp, &nstates, 0, req);
|
|
|
|
return (error);
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Returns size of dynamic states in legacy format
|
|
*/
|
|
int
|
|
ipfw_dyn_len(void)
|
|
{
|
|
|
|
return (V_ipfw_dyn_v == NULL) ? 0 :
|
|
(DYN_COUNT * sizeof(ipfw_dyn_rule));
|
|
}
|
|
|
|
/*
|
|
* Returns number of dynamic states.
|
|
* Used by dump format v1 (current).
|
|
*/
|
|
int
|
|
ipfw_dyn_get_count(void)
|
|
{
|
|
|
|
return (V_ipfw_dyn_v == NULL) ? 0 : DYN_COUNT;
|
|
}
|
|
|
|
static void
|
|
export_dyn_rule(ipfw_dyn_rule *src, ipfw_dyn_rule *dst)
|
|
{
|
|
|
|
memcpy(dst, src, sizeof(*src));
|
|
memcpy(&(dst->rule), &(src->rule->rulenum), sizeof(src->rule->rulenum));
|
|
/*
|
|
* store set number into high word of
|
|
* dst->rule pointer.
|
|
*/
|
|
memcpy((char *)&dst->rule + sizeof(src->rule->rulenum),
|
|
&(src->rule->set), sizeof(src->rule->set));
|
|
/*
|
|
* store a non-null value in "next".
|
|
* The userland code will interpret a
|
|
* NULL here as a marker
|
|
* for the last dynamic rule.
|
|
*/
|
|
memcpy(&dst->next, &dst, sizeof(dst));
|
|
dst->expire =
|
|
TIME_LEQ(dst->expire, time_uptime) ? 0 : dst->expire - time_uptime;
|
|
}
|
|
|
|
/*
|
|
* Fills int buffer given by @sd with dynamic states.
|
|
* Used by dump format v1 (current).
|
|
*
|
|
* Returns 0 on success.
|
|
*/
|
|
int
|
|
ipfw_dump_states(struct ip_fw_chain *chain, struct sockopt_data *sd)
|
|
{
|
|
ipfw_dyn_rule *p;
|
|
ipfw_obj_dyntlv *dst, *last;
|
|
ipfw_obj_ctlv *ctlv;
|
|
int i;
|
|
size_t sz;
|
|
|
|
if (V_ipfw_dyn_v == NULL)
|
|
return (0);
|
|
|
|
IPFW_UH_RLOCK_ASSERT(chain);
|
|
|
|
ctlv = (ipfw_obj_ctlv *)ipfw_get_sopt_space(sd, sizeof(*ctlv));
|
|
if (ctlv == NULL)
|
|
return (ENOMEM);
|
|
sz = sizeof(ipfw_obj_dyntlv);
|
|
ctlv->head.type = IPFW_TLV_DYNSTATE_LIST;
|
|
ctlv->objsize = sz;
|
|
last = NULL;
|
|
|
|
for (i = 0 ; i < V_curr_dyn_buckets; i++) {
|
|
IPFW_BUCK_LOCK(i);
|
|
for (p = V_ipfw_dyn_v[i].head ; p != NULL; p = p->next) {
|
|
dst = (ipfw_obj_dyntlv *)ipfw_get_sopt_space(sd, sz);
|
|
if (dst == NULL) {
|
|
IPFW_BUCK_UNLOCK(i);
|
|
return (ENOMEM);
|
|
}
|
|
|
|
export_dyn_rule(p, &dst->state);
|
|
dst->head.length = sz;
|
|
dst->head.type = IPFW_TLV_DYN_ENT;
|
|
last = dst;
|
|
}
|
|
IPFW_BUCK_UNLOCK(i);
|
|
}
|
|
|
|
if (last != NULL) /* mark last dynamic rule */
|
|
last->head.flags = IPFW_DF_LAST;
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Fill given buffer with dynamic states (legacy format).
|
|
* IPFW_UH_RLOCK has to be held while calling.
|
|
*/
|
|
void
|
|
ipfw_get_dynamic(struct ip_fw_chain *chain, char **pbp, const char *ep)
|
|
{
|
|
ipfw_dyn_rule *p, *last = NULL;
|
|
char *bp;
|
|
int i;
|
|
|
|
if (V_ipfw_dyn_v == NULL)
|
|
return;
|
|
bp = *pbp;
|
|
|
|
IPFW_UH_RLOCK_ASSERT(chain);
|
|
|
|
for (i = 0 ; i < V_curr_dyn_buckets; i++) {
|
|
IPFW_BUCK_LOCK(i);
|
|
for (p = V_ipfw_dyn_v[i].head ; p != NULL; p = p->next) {
|
|
if (bp + sizeof *p <= ep) {
|
|
ipfw_dyn_rule *dst =
|
|
(ipfw_dyn_rule *)bp;
|
|
|
|
export_dyn_rule(p, dst);
|
|
last = dst;
|
|
bp += sizeof(ipfw_dyn_rule);
|
|
}
|
|
}
|
|
IPFW_BUCK_UNLOCK(i);
|
|
}
|
|
|
|
if (last != NULL) /* mark last dynamic rule */
|
|
bzero(&last->next, sizeof(last));
|
|
*pbp = bp;
|
|
}
|
|
/* end of file */
|