diff options
Diffstat (limited to 'freebsd/sys/netpfil/ipfw/ip_fw_dynamic.c')
| -rw-r--r-- | freebsd/sys/netpfil/ipfw/ip_fw_dynamic.c | 1822 |
1 files changed, 1822 insertions, 0 deletions
diff --git a/freebsd/sys/netpfil/ipfw/ip_fw_dynamic.c b/freebsd/sys/netpfil/ipfw/ip_fw_dynamic.c new file mode 100644 index 00000000..4696faac --- /dev/null +++ b/freebsd/sys/netpfil/ipfw/ip_fw_dynamic.c @@ -0,0 +1,1822 @@ +#include <machine/rtems-bsd-kernel-space.h> + +/*- + * 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 <rtems/bsd/local/opt_ipfw.h> +#include <rtems/bsd/local/opt_inet.h> +#ifndef INET +#error IPFIREWALL requires INET. +#endif /* INET */ +#include <rtems/bsd/local/opt_inet6.h> + +#include <rtems/bsd/sys/param.h> +#include <sys/systm.h> +#include <sys/malloc.h> +#include <sys/mbuf.h> +#include <sys/kernel.h> +#include <sys/ktr.h> +#include <rtems/bsd/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/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]) ^ + (id->dst_port) ^ (id->src_port); + return 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) ^ (id->dst_port) ^ (id->src_port); + i &= (buckets - 1); + return i; +} + +#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) { + 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) +{ + + 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 */ |