d/freebsd-skq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
ca20f8ec29
freebsd-skq/sys/netpfil/ipfw/ip_fw_dynamic.c
Andrey V. Elsukov 1ca7c3b815 The rule field in the ipfw_dyn_rule structure is used as storage 
to pass rule number and rule set to userland. In r272840 the kernel
internal rule representation was changed and the rulenum field of
struct ip_fw_rule got the type uint32_t, but userlevel representation
still have the type uint16_t. To not overflow the size of pointer
on the systems with 32-bit pointer size use separate variable to
copy rulenum and set.

Reported by:	PVS-Studio
MFC after:	1 week
2017-04-14 11:19:09 +00:00

1822 lines
46 KiB
C
Raw Blame History

/*-
* Copyright (c) 2002 Luigi Rizzo, Universita` di Pisa
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#define DEB(x)
#define DDB(x) x
/*
* Dynamic rule support for ipfw
*/
#include "opt_ipfw.h"
#include "opt_inet.h"
#ifndef INET
#error IPFIREWALL requires INET.
#endif /* INET */
#include "opt_inet6.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/lock.h>
#include <sys/rmlock.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <net/ethernet.h> /* for ETHERTYPE_IP */
#include <net/if.h>
#include <net/if_var.h>
#include <net/pfil.h>
#include <net/vnet.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h> /* ip_defttl */
#include <netinet/ip_fw.h>
#include <netinet/tcp_var.h>
#include <netinet/udp.h>
#include <netinet/ip6.h> /* IN6_ARE_ADDR_EQUAL */
#ifdef INET6
#include <netinet6/in6_var.h>
#include <netinet6/ip6_var.h>
#endif
#include <netpfil/ipfw/ip_fw_private.h>
#include <machine/in_cksum.h> /* XXX for in_cksum */
#ifdef MAC
#include <security/mac/mac_framework.h>
#endif
/*
* Description of dynamic rules.
*
* Dynamic rules are stored in lists accessed through a hash table
* (ipfw_dyn_v) whose size is curr_dyn_buckets. This value can
* be modified through the sysctl variable dyn_buckets which is
* updated when the table becomes empty.
*
* XXX currently there is only one list, ipfw_dyn.
*
* When a packet is received, its address fields are first masked
* with the mask defined for the rule, then hashed, then matched
* against the entries in the corresponding list.
* Dynamic rules can be used for different purposes:
* + stateful rules;
* + enforcing limits on the number of sessions;
* + in-kernel NAT (not implemented yet)
*
* The lifetime of dynamic rules is regulated by dyn_*_lifetime,
* measured in seconds and depending on the flags.
*
* The total number of dynamic rules is equal to UMA zone items count.
* The max number of dynamic rules is dyn_max. When we reach
* the maximum number of rules we do not create anymore. This is
* done to avoid consuming too much memory, but also too much
* time when searching on each packet (ideally, we should try instead
* to put a limit on the length of the list on each bucket...).
*
* Each dynamic rule holds a pointer to the parent ipfw rule so
* we know what action to perform. Dynamic rules are removed when
* the parent rule is deleted. This can be changed by dyn_keep_states
* sysctl.
*
* There are some limitations with dynamic rules -- we do not
* obey the 'randomized match', and we do not do multiple
* passes through the firewall. XXX check the latter!!!
*/
struct ipfw_dyn_bucket {
struct mtx mtx; /* Bucket protecting lock */
ipfw_dyn_rule *head; /* Pointer to first rule */
};
/*
* Static variables followed by global ones
*/
static VNET_DEFINE(struct ipfw_dyn_bucket *, ipfw_dyn_v);
static VNET_DEFINE(u_int32_t, dyn_buckets_max);
static VNET_DEFINE(u_int32_t, curr_dyn_buckets);
static VNET_DEFINE(struct callout, ipfw_timeout);
#define V_ipfw_dyn_v VNET(ipfw_dyn_v)
#define V_dyn_buckets_max VNET(dyn_buckets_max)
#define V_curr_dyn_buckets VNET(curr_dyn_buckets)
#define V_ipfw_timeout VNET(ipfw_timeout)
static VNET_DEFINE(uma_zone_t, ipfw_dyn_rule_zone);
#define V_ipfw_dyn_rule_zone VNET(ipfw_dyn_rule_zone)
#define IPFW_BUCK_LOCK_INIT(b) \
mtx_init(&(b)->mtx, "IPFW dynamic bucket", NULL, MTX_DEF)
#define IPFW_BUCK_LOCK_DESTROY(b) \
mtx_destroy(&(b)->mtx)
#define IPFW_BUCK_LOCK(i) mtx_lock(&V_ipfw_dyn_v[(i)].mtx)
#define IPFW_BUCK_UNLOCK(i) mtx_unlock(&V_ipfw_dyn_v[(i)].mtx)
#define IPFW_BUCK_ASSERT(i) mtx_assert(&V_ipfw_dyn_v[(i)].mtx, MA_OWNED)
static VNET_DEFINE(int, dyn_keep_states);
#define V_dyn_keep_states VNET(dyn_keep_states)
/*
* Timeouts for various events in handing dynamic rules.
*/
static VNET_DEFINE(u_int32_t, dyn_ack_lifetime);
static VNET_DEFINE(u_int32_t, dyn_syn_lifetime);
static VNET_DEFINE(u_int32_t, dyn_fin_lifetime);
static VNET_DEFINE(u_int32_t, dyn_rst_lifetime);
static VNET_DEFINE(u_int32_t, dyn_udp_lifetime);
static VNET_DEFINE(u_int32_t, dyn_short_lifetime);
#define V_dyn_ack_lifetime VNET(dyn_ack_lifetime)
#define V_dyn_syn_lifetime VNET(dyn_syn_lifetime)
#define V_dyn_fin_lifetime VNET(dyn_fin_lifetime)
#define V_dyn_rst_lifetime VNET(dyn_rst_lifetime)
#define V_dyn_udp_lifetime VNET(dyn_udp_lifetime)
#define V_dyn_short_lifetime VNET(dyn_short_lifetime)
/*
* Keepalives are sent if dyn_keepalive is set. They are sent every
* dyn_keepalive_period seconds, in the last dyn_keepalive_interval
* seconds of lifetime of a rule.
* dyn_rst_lifetime and dyn_fin_lifetime should be strictly lower
* than dyn_keepalive_period.
*/
static VNET_DEFINE(u_int32_t, dyn_keepalive_interval);
static VNET_DEFINE(u_int32_t, dyn_keepalive_period);
static VNET_DEFINE(u_int32_t, dyn_keepalive);
static VNET_DEFINE(time_t, dyn_keepalive_last);
#define V_dyn_keepalive_interval VNET(dyn_keepalive_interval)
#define V_dyn_keepalive_period VNET(dyn_keepalive_period)
#define V_dyn_keepalive VNET(dyn_keepalive)
#define V_dyn_keepalive_last VNET(dyn_keepalive_last)
static VNET_DEFINE(u_int32_t, dyn_max); /* max # of dynamic rules */
#define DYN_COUNT uma_zone_get_cur(V_ipfw_dyn_rule_zone)
#define V_dyn_max VNET(dyn_max)
/* for userspace, we emulate the uma_zone_counter with ipfw_dyn_count */
static int ipfw_dyn_count; /* number of objects */
#ifdef USERSPACE /* emulation of UMA object counters for userspace */
#define uma_zone_get_cur(x) ipfw_dyn_count
#endif /* USERSPACE */
static int last_log; /* Log ratelimiting */
static void ipfw_dyn_tick(void *vnetx);
static void check_dyn_rules(struct ip_fw_chain *, ipfw_range_tlv *, int, int);
#ifdef SYSCTL_NODE
static int sysctl_ipfw_dyn_count(SYSCTL_HANDLER_ARGS);
static int sysctl_ipfw_dyn_max(SYSCTL_HANDLER_ARGS);
SYSBEGIN(f2)
SYSCTL_DECL(_net_inet_ip_fw);
SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_buckets,
CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_buckets_max), 0,
"Max number of dyn. buckets");
SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, curr_dyn_buckets,
CTLFLAG_VNET | CTLFLAG_RD, &VNET_NAME(curr_dyn_buckets), 0,
"Current Number of dyn. buckets");
SYSCTL_PROC(_net_inet_ip_fw, OID_AUTO, dyn_count,
CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RD, 0, 0, sysctl_ipfw_dyn_count, "IU",
"Number of dyn. rules");
SYSCTL_PROC(_net_inet_ip_fw, OID_AUTO, dyn_max,
CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW, 0, 0, sysctl_ipfw_dyn_max, "IU",
"Max number of dyn. rules");
SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_ack_lifetime,
CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_ack_lifetime), 0,
"Lifetime of dyn. rules for acks");
SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_syn_lifetime,
CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_syn_lifetime), 0,
"Lifetime of dyn. rules for syn");
SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_fin_lifetime,
CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_fin_lifetime), 0,
"Lifetime of dyn. rules for fin");
SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_rst_lifetime,
CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_rst_lifetime), 0,
"Lifetime of dyn. rules for rst");
SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_udp_lifetime,
CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_udp_lifetime), 0,
"Lifetime of dyn. rules for UDP");
SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_short_lifetime,
CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_short_lifetime), 0,
"Lifetime of dyn. rules for other situations");
SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_keepalive,
CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_keepalive), 0,
"Enable keepalives for dyn. rules");
SYSCTL_UINT(_net_inet_ip_fw, OID_AUTO, dyn_keep_states,
CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_keep_states), 0,
"Do not flush dynamic states on rule deletion");
SYSEND
#endif /* SYSCTL_NODE */
#ifdef INET6
static __inline int
hash_packet6(struct ipfw_flow_id *id)
{
u_int32_t i;
i = (id->dst_ip6.__u6_addr.__u6_addr32[2]) ^
(id->dst_ip6.__u6_addr.__u6_addr32[3]) ^
(id->src_ip6.__u6_addr.__u6_addr32[2]) ^
(id->src_ip6.__u6_addr.__u6_addr32[3]);
return ntohl(i);
}
#endif
/*
* IMPORTANT: the hash function for dynamic rules must be commutative
* in source and destination (ip,port), because rules are bidirectional
* and we want to find both in the same bucket.
*/
static __inline int
hash_packet(struct ipfw_flow_id *id, int buckets)
{
u_int32_t i;
#ifdef INET6
if (IS_IP6_FLOW_ID(id))
i = hash_packet6(id);
else
#endif /* INET6 */
i = (id->dst_ip) ^ (id->src_ip);
i ^= (id->dst_port) ^ (id->src_port);
return (i & (buckets - 1));
}
#if 0
#define DYN_DEBUG(fmt, ...) do { \
printf("%s: " fmt "\n", __func__, __VA_ARGS__); \
} while (0)
#else
#define DYN_DEBUG(fmt, ...)
#endif
static char *default_state_name = "default";
struct dyn_state_obj {
struct named_object no;
char name[64];
};
#define DYN_STATE_OBJ(ch, cmd) \
((struct dyn_state_obj *)SRV_OBJECT(ch, (cmd)->arg1))
/*
* Classifier callback.
* Return 0 if opcode contains object that should be referenced
* or rewritten.
*/
static int
dyn_classify(ipfw_insn *cmd, uint16_t *puidx, uint8_t *ptype)
{
DYN_DEBUG("opcode %d, arg1 %d", cmd->opcode, cmd->arg1);
/* Don't rewrite "check-state any" */
if (cmd->arg1 == 0 &&
cmd->opcode == O_CHECK_STATE)
return (1);
*puidx = cmd->arg1;
*ptype = 0;
return (0);
}
static void
dyn_update(ipfw_insn *cmd, uint16_t idx)
{
cmd->arg1 = idx;
DYN_DEBUG("opcode %d, arg1 %d", cmd->opcode, cmd->arg1);
}
static int
dyn_findbyname(struct ip_fw_chain *ch, struct tid_info *ti,
struct named_object **pno)
{
ipfw_obj_ntlv *ntlv;
const char *name;
DYN_DEBUG("uidx %d", ti->uidx);
if (ti->uidx != 0) {
if (ti->tlvs == NULL)
return (EINVAL);
/* Search ntlv in the buffer provided by user */
ntlv = ipfw_find_name_tlv_type(ti->tlvs, ti->tlen, ti->uidx,
IPFW_TLV_STATE_NAME);
if (ntlv == NULL)
return (EINVAL);
name = ntlv->name;
} else
name = default_state_name;
/*
* Search named object with corresponding name.
* Since states objects are global - ignore the set value
* and use zero instead.
*/
*pno = ipfw_objhash_lookup_name_type(CHAIN_TO_SRV(ch), 0,
IPFW_TLV_STATE_NAME, name);
/*
* We always return success here.
* The caller will check *pno and mark object as unresolved,
* then it will automatically create "default" object.
*/
return (0);
}
static struct named_object *
dyn_findbykidx(struct ip_fw_chain *ch, uint16_t idx)
{
DYN_DEBUG("kidx %d", idx);
return (ipfw_objhash_lookup_kidx(CHAIN_TO_SRV(ch), idx));
}
static int
dyn_create(struct ip_fw_chain *ch, struct tid_info *ti,
uint16_t *pkidx)
{
struct namedobj_instance *ni;
struct dyn_state_obj *obj;
struct named_object *no;
ipfw_obj_ntlv *ntlv;
char *name;
DYN_DEBUG("uidx %d", ti->uidx);
if (ti->uidx != 0) {
if (ti->tlvs == NULL)
return (EINVAL);
ntlv = ipfw_find_name_tlv_type(ti->tlvs, ti->tlen, ti->uidx,
IPFW_TLV_STATE_NAME);
if (ntlv == NULL)
return (EINVAL);
name = ntlv->name;
} else
name = default_state_name;
ni = CHAIN_TO_SRV(ch);
obj = malloc(sizeof(*obj), M_IPFW, M_WAITOK | M_ZERO);
obj->no.name = obj->name;
obj->no.etlv = IPFW_TLV_STATE_NAME;
strlcpy(obj->name, name, sizeof(obj->name));
IPFW_UH_WLOCK(ch);
no = ipfw_objhash_lookup_name_type(ni, 0,
IPFW_TLV_STATE_NAME, name);
if (no != NULL) {
/*
* Object is already created.
* Just return its kidx and bump refcount.
*/
*pkidx = no->kidx;
no->refcnt++;
IPFW_UH_WUNLOCK(ch);
free(obj, M_IPFW);
DYN_DEBUG("\tfound kidx %d", *pkidx);
return (0);
}
if (ipfw_objhash_alloc_idx(ni, &obj->no.kidx) != 0) {
DYN_DEBUG("\talloc_idx failed for %s", name);
IPFW_UH_WUNLOCK(ch);
free(obj, M_IPFW);
return (ENOSPC);
}
ipfw_objhash_add(ni, &obj->no);
IPFW_WLOCK(ch);
SRV_OBJECT(ch, obj->no.kidx) = obj;
IPFW_WUNLOCK(ch);
obj->no.refcnt++;
*pkidx = obj->no.kidx;
IPFW_UH_WUNLOCK(ch);
DYN_DEBUG("\tcreated kidx %d", *pkidx);
return (0);
}
static void
dyn_destroy(struct ip_fw_chain *ch, struct named_object *no)
{
struct dyn_state_obj *obj;
IPFW_UH_WLOCK_ASSERT(ch);
KASSERT(no->refcnt == 1,
("Destroying object '%s' (type %u, idx %u) with refcnt %u",
no->name, no->etlv, no->kidx, no->refcnt));
DYN_DEBUG("kidx %d", no->kidx);
IPFW_WLOCK(ch);
obj = SRV_OBJECT(ch, no->kidx);
SRV_OBJECT(ch, no->kidx) = NULL;
IPFW_WUNLOCK(ch);
ipfw_objhash_del(CHAIN_TO_SRV(ch), no);
ipfw_objhash_free_idx(CHAIN_TO_SRV(ch), no->kidx);
free(obj, M_IPFW);
}
static struct opcode_obj_rewrite dyn_opcodes[] = {
{
O_KEEP_STATE, IPFW_TLV_STATE_NAME,
dyn_classify, dyn_update,
dyn_findbyname, dyn_findbykidx,
dyn_create, dyn_destroy
},
{
O_CHECK_STATE, IPFW_TLV_STATE_NAME,
dyn_classify, dyn_update,
dyn_findbyname, dyn_findbykidx,
dyn_create, dyn_destroy
},
{
O_PROBE_STATE, IPFW_TLV_STATE_NAME,
dyn_classify, dyn_update,
dyn_findbyname, dyn_findbykidx,
dyn_create, dyn_destroy
},
{
O_LIMIT, IPFW_TLV_STATE_NAME,
dyn_classify, dyn_update,
dyn_findbyname, dyn_findbykidx,
dyn_create, dyn_destroy
},
};
/**
* Print customizable flow id description via log(9) facility.
*/
static void
print_dyn_rule_flags(struct ipfw_flow_id *id, int dyn_type, int log_flags,
char *prefix, char *postfix)
{
struct in_addr da;
#ifdef INET6
char src[INET6_ADDRSTRLEN], dst[INET6_ADDRSTRLEN];
#else
char src[INET_ADDRSTRLEN], dst[INET_ADDRSTRLEN];
#endif
#ifdef INET6
if (IS_IP6_FLOW_ID(id)) {
ip6_sprintf(src, &id->src_ip6);
ip6_sprintf(dst, &id->dst_ip6);
} else
#endif
{
da.s_addr = htonl(id->src_ip);
inet_ntop(AF_INET, &da, src, sizeof(src));
da.s_addr = htonl(id->dst_ip);
inet_ntop(AF_INET, &da, dst, sizeof(dst));
}
log(log_flags, "ipfw: %s type %d %s %d -> %s %d, %d %s\n",
prefix, dyn_type, src, id->src_port, dst,
id->dst_port, DYN_COUNT, postfix);
}
#define print_dyn_rule(id, dtype, prefix, postfix) \
print_dyn_rule_flags(id, dtype, LOG_DEBUG, prefix, postfix)
#define TIME_LEQ(a,b) ((int)((a)-(b)) <= 0)
#define TIME_LE(a,b) ((int)((a)-(b)) < 0)
static void
dyn_update_proto_state(ipfw_dyn_rule *q, const struct ipfw_flow_id *id,
const struct tcphdr *tcp, int dir)
{
uint32_t ack;
u_char flags;
if (id->proto == IPPROTO_TCP) {
flags = id->_flags & (TH_FIN | TH_SYN | TH_RST);
#define BOTH_SYN (TH_SYN | (TH_SYN << 8))
#define BOTH_FIN (TH_FIN | (TH_FIN << 8))
#define TCP_FLAGS (TH_FLAGS | (TH_FLAGS << 8))
#define ACK_FWD 0x10000 /* fwd ack seen */
#define ACK_REV 0x20000 /* rev ack seen */
q->state |= (dir == MATCH_FORWARD) ? flags : (flags << 8);
switch (q->state & TCP_FLAGS) {
case TH_SYN: /* opening */
q->expire = time_uptime + V_dyn_syn_lifetime;
break;
case BOTH_SYN: /* move to established */
case BOTH_SYN | TH_FIN: /* one side tries to close */
case BOTH_SYN | (TH_FIN << 8):
#define _SEQ_GE(a,b) ((int)(a) - (int)(b) >= 0)
if (tcp == NULL)
break;
ack = ntohl(tcp->th_ack);
if (dir == MATCH_FORWARD) {
if (q->ack_fwd == 0 ||
_SEQ_GE(ack, q->ack_fwd)) {
q->ack_fwd = ack;
q->state |= ACK_FWD;
}
} else {
if (q->ack_rev == 0 ||
_SEQ_GE(ack, q->ack_rev)) {
q->ack_rev = ack;
q->state |= ACK_REV;
}
}
if ((q->state & (ACK_FWD | ACK_REV)) ==
(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 (id->proto == IPPROTO_UDP) {
q->expire = time_uptime + V_dyn_udp_lifetime;
} else {
/* other protocols */
q->expire = time_uptime + V_dyn_short_lifetime;
}
}
/*
* Lookup a dynamic rule, locked version.
*/
static ipfw_dyn_rule *
lookup_dyn_rule_locked(struct ipfw_flow_id *pkt, int i, int *match_direction,
struct tcphdr *tcp, uint16_t kidx)
{
/*
* Stateful ipfw extensions.
* Lookup into dynamic session queue.
*/
ipfw_dyn_rule *prev, *q = NULL;
int dir;
IPFW_BUCK_ASSERT(i);
dir = MATCH_NONE;
for (prev = NULL, q = V_ipfw_dyn_v[i].head; q; prev = q, q = q->next) {
if (q->dyn_type == O_LIMIT_PARENT)
continue;
if (pkt->proto != q->id.proto)
continue;
if (kidx != 0 && kidx != q->kidx)
continue;
if (IS_IP6_FLOW_ID(pkt)) {
if (IN6_ARE_ADDR_EQUAL(&pkt->src_ip6, &q->id.src_ip6) &&
IN6_ARE_ADDR_EQUAL(&pkt->dst_ip6, &q->id.dst_ip6) &&
pkt->src_port == q->id.src_port &&
pkt->dst_port == q->id.dst_port) {
dir = MATCH_FORWARD;
break;
}
if (IN6_ARE_ADDR_EQUAL(&pkt->src_ip6, &q->id.dst_ip6) &&
IN6_ARE_ADDR_EQUAL(&pkt->dst_ip6, &q->id.src_ip6) &&
pkt->src_port == q->id.dst_port &&
pkt->dst_port == q->id.src_port) {
dir = MATCH_REVERSE;
break;
}
} else {
if (pkt->src_ip == q->id.src_ip &&
pkt->dst_ip == q->id.dst_ip &&
pkt->src_port == q->id.src_port &&
pkt->dst_port == q->id.dst_port) {
dir = MATCH_FORWARD;
break;
}
if (pkt->src_ip == q->id.dst_ip &&
pkt->dst_ip == q->id.src_ip &&
pkt->src_port == q->id.dst_port &&
pkt->dst_port == q->id.src_port) {
dir = MATCH_REVERSE;
break;
}
}
}
if (q == NULL)
goto done; /* q = NULL, not found */
if (prev != NULL) { /* found and not in front */
prev->next = q->next;
q->next = V_ipfw_dyn_v[i].head;
V_ipfw_dyn_v[i].head = q;
}
/* update state according to flags */
dyn_update_proto_state(q, pkt, tcp, dir);
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, uint16_t kidx)
{
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, kidx);
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, uint8_t dyn_type,
struct ip_fw *rule, uint16_t kidx)
{
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->kidx = kidx;
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,
uint16_t kidx)
{
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 &&
kidx == q->kidx &&
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, kidx);
}
/**
* 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",
(cmd->o.arg1 == 0 ? "": DYN_STATE_OBJ(chain, &cmd->o)->name));)
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, cmd->o.arg1);
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,
cmd->o.arg1);
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);
parent = lookup_dyn_parent(&id, &pindex, rule, cmd->o.arg1);
if (parent == 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) {
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, cmd->o.arg1);
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 */
}
dyn_update_proto_state(q, &args->f_id, NULL, MATCH_FORWARD);
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 maintenance
* 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 through all dynamic states doing generic maintenance:
* 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);
IPFW_ADD_OBJ_REWRITER(IS_DEFAULT_VNET(curvnet), dyn_opcodes);
}
void
ipfw_dyn_uninit(int pass)
{
int i;
if (pass == 0) {
callout_drain(&V_ipfw_timeout);
return;
}
IPFW_DEL_OBJ_REWRITER(IS_DEFAULT_VNET(curvnet), dyn_opcodes);
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)
{
uint16_t rulenum;
rulenum = (uint16_t)src->rule->rulenum;
memcpy(dst, src, sizeof(*src));
memcpy(&dst->rule, &rulenum, sizeof(rulenum));
/*
* store set number into high word of
* dst->rule pointer.
*/
memcpy((char *)&dst->rule + sizeof(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 */
Reference in New Issue View Git Blame Copy Permalink