0f56b10c4b
more on how ipfw(8) deals with tiny fragments. While we're at it, add a quick log message to even let people know we dropped a packet. (Note that the second FINE POINT is somewhat redundant given the first, but since the code is there, leave the docs for it.) MFC after: 1 day
2199 lines
58 KiB
C
2199 lines
58 KiB
C
/*
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* Copyright (c) 1993 Daniel Boulet
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* Copyright (c) 1994 Ugen J.S.Antsilevich
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* Copyright (c) 1996 Alex Nash
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* Copyright (c) 2000-2001 Luigi Rizzo
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*
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* Redistribution and use in source forms, with and without modification,
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* are permitted provided that this entire comment appears intact.
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*
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* Redistribution in binary form may occur without any restrictions.
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* Obviously, it would be nice if you gave credit where credit is due
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* but requiring it would be too onerous.
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*
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* This software is provided ``AS IS'' without any warranties of any kind.
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*
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* $FreeBSD$
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*/
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#define DEB(x)
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#define DDB(x) x
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/*
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* Implement IP packet firewall
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*/
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#if !defined(KLD_MODULE)
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#include "opt_ipfw.h"
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#include "opt_ipdn.h"
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#include "opt_ipdivert.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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#endif
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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/proc.h>
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#include <sys/socket.h>
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#include <sys/socketvar.h>
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#include <sys/sysctl.h>
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#include <sys/syslog.h>
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#include <sys/ucred.h>
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#include <net/if.h>
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#include <net/route.h>
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#include <netinet/in.h>
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#include <netinet/in_systm.h>
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#include <netinet/in_var.h>
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#include <netinet/in_pcb.h>
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#include <netinet/ip.h>
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#include <netinet/ip_var.h>
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#include <netinet/ip_icmp.h>
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#include <netinet/ip_fw.h>
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#include <netinet/ip_dummynet.h>
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#include <netinet/tcp.h>
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#include <netinet/tcp_timer.h>
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#include <netinet/tcp_var.h>
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#include <netinet/tcpip.h>
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#include <netinet/udp.h>
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#include <netinet/udp_var.h>
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#include <netinet/if_ether.h> /* XXX ethertype_ip */
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static int fw_debug = 1;
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#ifdef IPFIREWALL_VERBOSE
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static int fw_verbose = 1;
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#else
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static int fw_verbose = 0;
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#endif
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int fw_one_pass = 1 ;
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#ifdef IPFIREWALL_VERBOSE_LIMIT
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static int fw_verbose_limit = IPFIREWALL_VERBOSE_LIMIT;
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#else
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static int fw_verbose_limit = 0;
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#endif
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static int fw_permanent_rules = 0;
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/*
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* Right now, two fields in the IP header are changed to host format
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* by the IP layer before calling the firewall. Ideally, we would like
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* to have them in network format so that the packet can be
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* used as it comes from the device driver (and is thus readonly).
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*/
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static u_int64_t counter; /* counter for ipfw_report(NULL...) */
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struct ipfw_flow_id last_pkt ;
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#define IPFW_DEFAULT_RULE ((u_int)(u_short)~0)
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LIST_HEAD (ip_fw_head, ip_fw) ip_fw_chain_head;
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MALLOC_DEFINE(M_IPFW, "IpFw/IpAcct", "IpFw/IpAcct chain's");
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#ifdef SYSCTL_NODE
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SYSCTL_NODE(_net_inet_ip, OID_AUTO, fw, CTLFLAG_RW, 0, "Firewall");
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SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, enable, CTLFLAG_RW,
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&fw_enable, 0, "Enable ipfw");
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SYSCTL_INT(_net_inet_ip_fw, OID_AUTO,one_pass,CTLFLAG_RW,
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&fw_one_pass, 0,
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"Only do a single pass through ipfw when using dummynet(4)");
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SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, debug, CTLFLAG_RW,
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&fw_debug, 0, "Enable printing of debug ip_fw statements");
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SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, verbose, CTLFLAG_RW,
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&fw_verbose, 0, "Log matches to ipfw rules");
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SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, verbose_limit, CTLFLAG_RW,
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&fw_verbose_limit, 0, "Set upper limit of matches of ipfw rules logged");
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SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, permanent_rules, CTLFLAG_RW,
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&fw_permanent_rules, 0, "Set rule number, below which rules are permanent");
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/*
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* Extension for stateful ipfw.
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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, it is first hashed, then matched
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* against the entries in the corresponding list.
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* Matching occurs according to the rule type. The default is to
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* match the four fields and the protocol, and rules are bidirectional.
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*
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* For a busy proxy/web server we will have lots of connections to
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* the server. We could decide for a rule type where we ignore
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* ports (different hashing) and avoid special SYN/RST/FIN handling.
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*
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* XXX when we decide to support more than one rule type, we should
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* repeat the hashing multiple times uing only the useful fields.
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* Or, we could run the various tests in parallel, because the
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* 'move to front' technique should shorten the average search.
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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 stored in dyn_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 rules 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.
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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.
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* XXX check the latter!!!
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*/
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static struct ipfw_dyn_rule **ipfw_dyn_v = NULL ;
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static u_int32_t dyn_buckets = 256 ; /* must be power of 2 */
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static u_int32_t curr_dyn_buckets = 256 ; /* must be power of 2 */
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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 u_int32_t dyn_ack_lifetime = 300 ;
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static u_int32_t dyn_syn_lifetime = 20 ;
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static u_int32_t dyn_fin_lifetime = 1 ;
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static u_int32_t dyn_rst_lifetime = 1 ;
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static u_int32_t dyn_udp_lifetime = 10 ;
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static u_int32_t dyn_short_lifetime = 5 ;
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/*
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* after reaching 0, dynamic rules are considered still valid for
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* an additional grace time, unless there is lack of resources.
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*/
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static u_int32_t dyn_grace_time = 10 ;
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static u_int32_t static_count = 0 ; /* # of static rules */
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static u_int32_t dyn_count = 0 ; /* # of dynamic rules */
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static u_int32_t dyn_max = 1000 ; /* max # of dynamic rules */
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SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_buckets, CTLFLAG_RW,
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&dyn_buckets, 0, "Number of dyn. buckets");
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SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, curr_dyn_buckets, CTLFLAG_RD,
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&curr_dyn_buckets, 0, "Current Number of dyn. buckets");
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SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_count, CTLFLAG_RD,
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&dyn_count, 0, "Number of dyn. rules");
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SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_max, CTLFLAG_RW,
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&dyn_max, 0, "Max number of dyn. rules");
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SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, static_count, CTLFLAG_RD,
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&static_count, 0, "Number of static rules");
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SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_ack_lifetime, CTLFLAG_RW,
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&dyn_ack_lifetime, 0, "Lifetime of dyn. rules for acks");
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SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_syn_lifetime, CTLFLAG_RW,
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&dyn_syn_lifetime, 0, "Lifetime of dyn. rules for syn");
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SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_fin_lifetime, CTLFLAG_RW,
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&dyn_fin_lifetime, 0, "Lifetime of dyn. rules for fin");
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SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_rst_lifetime, CTLFLAG_RW,
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&dyn_rst_lifetime, 0, "Lifetime of dyn. rules for rst");
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SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_udp_lifetime, CTLFLAG_RW,
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&dyn_udp_lifetime, 0, "Lifetime of dyn. rules for UDP");
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SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_short_lifetime, CTLFLAG_RW,
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&dyn_short_lifetime, 0, "Lifetime of dyn. rules for other situations");
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SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_grace_time, CTLFLAG_RD,
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&dyn_grace_time, 0, "Grace time for dyn. rules");
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#endif /* SYSCTL_NODE */
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#define dprintf(a) do { \
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if (fw_debug) \
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printf a; \
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} while (0)
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#define SNPARGS(buf, len) buf + len, sizeof(buf) > len ? sizeof(buf) - len : 0
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static int add_entry (struct ip_fw_head *chainptr, struct ip_fw *frwl);
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static int del_entry (struct ip_fw_head *chainptr, u_short number);
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static int zero_entry (struct ip_fw *, int);
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static int check_ipfw_struct (struct ip_fw *m);
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static int iface_match (struct ifnet *ifp, union ip_fw_if *ifu,
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int byname);
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static int ipopts_match (struct ip *ip, struct ip_fw *f);
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static int iptos_match (struct ip *ip, struct ip_fw *f);
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static __inline int
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port_match (u_short *portptr, int nports, u_short port,
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int range_flag, int mask);
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static int tcpflg_match (struct tcphdr *tcp, struct ip_fw *f);
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static int icmptype_match (struct icmp * icmp, struct ip_fw * f);
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static void ipfw_report (struct ip_fw *f, struct ip *ip, int offset,
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int ip_len, struct ifnet *rif,
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struct ifnet *oif);
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static void flush_rule_ptrs(void);
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static int ip_fw_chk (struct ip **pip, int hlen,
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struct ifnet *oif, u_int16_t *cookie, struct mbuf **m,
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struct ip_fw **flow_id,
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struct sockaddr_in **next_hop);
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static int ip_fw_ctl (struct sockopt *sopt);
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ip_dn_ruledel_t *ip_dn_ruledel_ptr = NULL;
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static char err_prefix[] = "ip_fw_ctl:";
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/*
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* Returns 1 if the port is matched by the vector, 0 otherwise
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*/
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static __inline int
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port_match(u_short *portptr, int nports, u_short port, int range_flag, int mask)
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{
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if (!nports)
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return 1;
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if (mask) {
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if ( 0 == ((portptr[0] ^ port) & portptr[1]) )
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return 1;
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nports -= 2;
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portptr += 2;
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}
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if (range_flag) {
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if (portptr[0] <= port && port <= portptr[1])
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return 1;
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nports -= 2;
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portptr += 2;
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}
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while (nports-- > 0)
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if (*portptr++ == port)
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return 1;
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return 0;
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}
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static int
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tcpflg_match(struct tcphdr *tcp, struct ip_fw *f)
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{
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u_char flg_set, flg_clr;
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/*
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* If an established connection is required, reject packets that
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* have only SYN of RST|ACK|SYN set. Otherwise, fall through to
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* other flag requirements.
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*/
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if ((f->fw_ipflg & IP_FW_IF_TCPEST) &&
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((tcp->th_flags & (IP_FW_TCPF_RST | IP_FW_TCPF_ACK |
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IP_FW_TCPF_SYN)) == IP_FW_TCPF_SYN))
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return 0;
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flg_set = tcp->th_flags & f->fw_tcpf;
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flg_clr = tcp->th_flags & f->fw_tcpnf;
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if (flg_set != f->fw_tcpf)
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return 0;
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if (flg_clr)
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return 0;
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return 1;
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}
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static int
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icmptype_match(struct icmp *icmp, struct ip_fw *f)
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{
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int type;
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if (!(f->fw_flg & IP_FW_F_ICMPBIT))
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return(1);
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type = icmp->icmp_type;
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/* check for matching type in the bitmap */
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if (type < IP_FW_ICMPTYPES_MAX &&
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(f->fw_uar.fw_icmptypes[type / (sizeof(unsigned) * NBBY)] &
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(1U << (type % (sizeof(unsigned) * NBBY)))))
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return(1);
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return(0); /* no match */
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}
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static int
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is_icmp_query(struct ip *ip)
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{
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const struct icmp *icmp;
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int icmp_type;
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icmp = (struct icmp *)((u_int32_t *)ip + ip->ip_hl);
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icmp_type = icmp->icmp_type;
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if (icmp_type == ICMP_ECHO || icmp_type == ICMP_ROUTERSOLICIT ||
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icmp_type == ICMP_TSTAMP || icmp_type == ICMP_IREQ ||
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icmp_type == ICMP_MASKREQ)
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return(1);
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return(0);
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}
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static int
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ipopts_match(struct ip *ip, struct ip_fw *f)
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{
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register u_char *cp;
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int opt, optlen, cnt;
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u_char opts, nopts, nopts_sve;
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cp = (u_char *)(ip + 1);
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cnt = (ip->ip_hl << 2) - sizeof (struct ip);
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opts = f->fw_ipopt;
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nopts = nopts_sve = f->fw_ipnopt;
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for (; cnt > 0; cnt -= optlen, cp += optlen) {
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opt = cp[IPOPT_OPTVAL];
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if (opt == IPOPT_EOL)
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break;
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if (opt == IPOPT_NOP)
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optlen = 1;
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else {
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optlen = cp[IPOPT_OLEN];
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if (optlen <= 0 || optlen > cnt) {
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return 0; /*XXX*/
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}
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}
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switch (opt) {
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default:
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break;
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case IPOPT_LSRR:
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opts &= ~IP_FW_IPOPT_LSRR;
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nopts &= ~IP_FW_IPOPT_LSRR;
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break;
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case IPOPT_SSRR:
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opts &= ~IP_FW_IPOPT_SSRR;
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nopts &= ~IP_FW_IPOPT_SSRR;
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break;
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case IPOPT_RR:
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opts &= ~IP_FW_IPOPT_RR;
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nopts &= ~IP_FW_IPOPT_RR;
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break;
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case IPOPT_TS:
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opts &= ~IP_FW_IPOPT_TS;
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nopts &= ~IP_FW_IPOPT_TS;
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break;
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}
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if (opts == nopts)
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break;
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}
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if (opts == 0 && nopts == nopts_sve)
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return 1;
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else
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return 0;
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}
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|
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static int
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iptos_match(struct ip *ip, struct ip_fw *f)
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{
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|
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u_int flags = (ip->ip_tos & 0x1f);
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u_char opts, nopts, nopts_sve;
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opts = (f->fw_iptos & 0x1f);
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nopts = nopts_sve = f->fw_ipntos;
|
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|
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while (flags != 0) {
|
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u_int flag;
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|
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flag = 1 << (ffs(flags) -1);
|
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opts &= ~flag;
|
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nopts &= ~flag;
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flags &= ~flag;
|
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}
|
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|
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if (opts == 0 && nopts == nopts_sve)
|
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return 1;
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else
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return 0;
|
|
|
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}
|
|
|
|
|
|
static int
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tcpopts_match(struct tcphdr *tcp, struct ip_fw *f)
|
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{
|
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register u_char *cp;
|
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int opt, optlen, cnt;
|
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u_char opts, nopts, nopts_sve;
|
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|
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cp = (u_char *)(tcp + 1);
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cnt = (tcp->th_off << 2) - sizeof (struct tcphdr);
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opts = f->fw_tcpopt;
|
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nopts = nopts_sve = f->fw_tcpnopt;
|
|
|
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for (; cnt > 0; cnt -= optlen, cp += optlen) {
|
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opt = cp[0];
|
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if (opt == TCPOPT_EOL)
|
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break;
|
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if (opt == TCPOPT_NOP)
|
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optlen = 1;
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else {
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optlen = cp[1];
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if (optlen <= 0)
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break;
|
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}
|
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|
|
|
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switch (opt) {
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|
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default:
|
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break;
|
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|
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case TCPOPT_MAXSEG:
|
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opts &= ~IP_FW_TCPOPT_MSS;
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nopts &= ~IP_FW_TCPOPT_MSS;
|
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break;
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|
|
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case TCPOPT_WINDOW:
|
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opts &= ~IP_FW_TCPOPT_WINDOW;
|
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nopts &= ~IP_FW_TCPOPT_WINDOW;
|
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break;
|
|
|
|
case TCPOPT_SACK_PERMITTED:
|
|
case TCPOPT_SACK:
|
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opts &= ~IP_FW_TCPOPT_SACK;
|
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nopts &= ~IP_FW_TCPOPT_SACK;
|
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break;
|
|
|
|
case TCPOPT_TIMESTAMP:
|
|
opts &= ~IP_FW_TCPOPT_TS;
|
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nopts &= ~IP_FW_TCPOPT_TS;
|
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break;
|
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|
|
case TCPOPT_CC:
|
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case TCPOPT_CCNEW:
|
|
case TCPOPT_CCECHO:
|
|
opts &= ~IP_FW_TCPOPT_CC;
|
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nopts &= ~IP_FW_TCPOPT_CC;
|
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break;
|
|
}
|
|
if (opts == nopts)
|
|
break;
|
|
}
|
|
if (opts == 0 && nopts == nopts_sve)
|
|
return 1;
|
|
else
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
iface_match(struct ifnet *ifp, union ip_fw_if *ifu, int byname)
|
|
{
|
|
/* Check by name or by IP address */
|
|
if (byname) {
|
|
/* Check unit number (-1 is wildcard) */
|
|
if (ifu->fu_via_if.unit != -1
|
|
&& ifp->if_unit != ifu->fu_via_if.unit)
|
|
return(0);
|
|
/* Check name */
|
|
if (strncmp(ifp->if_name, ifu->fu_via_if.name, FW_IFNLEN))
|
|
return(0);
|
|
return(1);
|
|
} else if (ifu->fu_via_ip.s_addr != 0) { /* Zero == wildcard */
|
|
struct ifaddr *ia;
|
|
|
|
TAILQ_FOREACH(ia, &ifp->if_addrhead, ifa_link) {
|
|
if (ia->ifa_addr == NULL)
|
|
continue;
|
|
if (ia->ifa_addr->sa_family != AF_INET)
|
|
continue;
|
|
if (ifu->fu_via_ip.s_addr != ((struct sockaddr_in *)
|
|
(ia->ifa_addr))->sin_addr.s_addr)
|
|
continue;
|
|
return(1);
|
|
}
|
|
return(0);
|
|
}
|
|
return(1);
|
|
}
|
|
|
|
static void
|
|
ipfw_report(struct ip_fw *f, struct ip *ip, int offset, int ip_len,
|
|
struct ifnet *rif, struct ifnet *oif)
|
|
{
|
|
struct tcphdr *const tcp = (struct tcphdr *) ((u_int32_t *) ip+ ip->ip_hl);
|
|
struct udphdr *const udp = (struct udphdr *) ((u_int32_t *) ip+ ip->ip_hl);
|
|
struct icmp *const icmp = (struct icmp *) ((u_int32_t *) ip + ip->ip_hl);
|
|
u_int64_t count;
|
|
char *action;
|
|
char action2[32], proto[47], name[18], fragment[27];
|
|
int len;
|
|
|
|
count = f ? f->fw_pcnt : ++counter;
|
|
if ((f == NULL && fw_verbose_limit != 0 && count > fw_verbose_limit) ||
|
|
(f && f->fw_logamount != 0 && count > f->fw_loghighest))
|
|
return;
|
|
|
|
/* Print command name */
|
|
snprintf(SNPARGS(name, 0), "ipfw: %d", f ? f->fw_number : -1);
|
|
|
|
action = action2;
|
|
if (!f)
|
|
action = "Refuse";
|
|
else {
|
|
switch (f->fw_flg & IP_FW_F_COMMAND) {
|
|
case IP_FW_F_DENY:
|
|
action = "Deny";
|
|
break;
|
|
case IP_FW_F_REJECT:
|
|
if (f->fw_reject_code == IP_FW_REJECT_RST)
|
|
action = "Reset";
|
|
else
|
|
action = "Unreach";
|
|
break;
|
|
case IP_FW_F_ACCEPT:
|
|
action = "Accept";
|
|
break;
|
|
case IP_FW_F_COUNT:
|
|
action = "Count";
|
|
break;
|
|
#ifdef IPDIVERT
|
|
case IP_FW_F_DIVERT:
|
|
snprintf(SNPARGS(action2, 0), "Divert %d",
|
|
f->fw_divert_port);
|
|
break;
|
|
case IP_FW_F_TEE:
|
|
snprintf(SNPARGS(action2, 0), "Tee %d",
|
|
f->fw_divert_port);
|
|
break;
|
|
#endif
|
|
case IP_FW_F_SKIPTO:
|
|
snprintf(SNPARGS(action2, 0), "SkipTo %d",
|
|
f->fw_skipto_rule);
|
|
break;
|
|
case IP_FW_F_PIPE:
|
|
snprintf(SNPARGS(action2, 0), "Pipe %d",
|
|
f->fw_skipto_rule);
|
|
break;
|
|
case IP_FW_F_QUEUE:
|
|
snprintf(SNPARGS(action2, 0), "Queue %d",
|
|
f->fw_skipto_rule);
|
|
break;
|
|
#ifdef IPFIREWALL_FORWARD
|
|
case IP_FW_F_FWD:
|
|
if (f->fw_fwd_ip.sin_port)
|
|
snprintf(SNPARGS(action2, 0),
|
|
"Forward to %s:%d",
|
|
inet_ntoa(f->fw_fwd_ip.sin_addr),
|
|
f->fw_fwd_ip.sin_port);
|
|
else
|
|
snprintf(SNPARGS(action2, 0), "Forward to %s",
|
|
inet_ntoa(f->fw_fwd_ip.sin_addr));
|
|
break;
|
|
#endif
|
|
default:
|
|
action = "UNKNOWN";
|
|
break;
|
|
}
|
|
}
|
|
|
|
switch (ip->ip_p) {
|
|
case IPPROTO_TCP:
|
|
len = snprintf(SNPARGS(proto, 0), "TCP %s",
|
|
inet_ntoa(ip->ip_src));
|
|
if (offset == 0)
|
|
len += snprintf(SNPARGS(proto, len), ":%d ",
|
|
ntohs(tcp->th_sport));
|
|
else
|
|
len += snprintf(SNPARGS(proto, len), " ");
|
|
len += snprintf(SNPARGS(proto, len), "%s",
|
|
inet_ntoa(ip->ip_dst));
|
|
if (offset == 0)
|
|
snprintf(SNPARGS(proto, len), ":%d",
|
|
ntohs(tcp->th_dport));
|
|
break;
|
|
case IPPROTO_UDP:
|
|
len = snprintf(SNPARGS(proto, 0), "UDP %s",
|
|
inet_ntoa(ip->ip_src));
|
|
if (offset == 0)
|
|
len += snprintf(SNPARGS(proto, len), ":%d ",
|
|
ntohs(udp->uh_sport));
|
|
else
|
|
len += snprintf(SNPARGS(proto, len), " ");
|
|
len += snprintf(SNPARGS(proto, len), "%s",
|
|
inet_ntoa(ip->ip_dst));
|
|
if (offset == 0)
|
|
snprintf(SNPARGS(proto, len), ":%d",
|
|
ntohs(udp->uh_dport));
|
|
break;
|
|
case IPPROTO_ICMP:
|
|
if (offset == 0)
|
|
len = snprintf(SNPARGS(proto, 0), "ICMP:%u.%u ",
|
|
icmp->icmp_type, icmp->icmp_code);
|
|
else
|
|
len = snprintf(SNPARGS(proto, 0), "ICMP ");
|
|
len += snprintf(SNPARGS(proto, len), "%s",
|
|
inet_ntoa(ip->ip_src));
|
|
snprintf(SNPARGS(proto, len), " %s", inet_ntoa(ip->ip_dst));
|
|
break;
|
|
default:
|
|
len = snprintf(SNPARGS(proto, 0), "P:%d %s", ip->ip_p,
|
|
inet_ntoa(ip->ip_src));
|
|
snprintf(SNPARGS(proto, len), " %s", inet_ntoa(ip->ip_dst));
|
|
break;
|
|
}
|
|
|
|
if (ip->ip_off & (IP_MF | IP_OFFMASK))
|
|
snprintf(SNPARGS(fragment, 0), " (frag %d:%d@%d%s)",
|
|
ntohs(ip->ip_id), ip_len - (ip->ip_hl << 2),
|
|
offset << 3,
|
|
(ip->ip_off & IP_MF) ? "+" : "");
|
|
else
|
|
fragment[0] = '\0';
|
|
if (oif)
|
|
log(LOG_SECURITY | LOG_INFO, "%s %s %s out via %s%d%s\n",
|
|
name, action, proto, oif->if_name, oif->if_unit, fragment);
|
|
else if (rif)
|
|
log(LOG_SECURITY | LOG_INFO, "%s %s %s in via %s%d%s\n", name,
|
|
action, proto, rif->if_name, rif->if_unit, fragment);
|
|
else
|
|
log(LOG_SECURITY | LOG_INFO, "%s %s %s%s\n", name, action,
|
|
proto, fragment);
|
|
if ((f ? f->fw_logamount != 0 : 1) &&
|
|
count == (f ? f->fw_loghighest : fw_verbose_limit))
|
|
log(LOG_SECURITY | LOG_NOTICE,
|
|
"ipfw: limit %d reached on entry %d\n",
|
|
f ? f->fw_logamount : fw_verbose_limit,
|
|
f ? f->fw_number : -1);
|
|
}
|
|
|
|
static __inline int
|
|
hash_packet(struct ipfw_flow_id *id)
|
|
{
|
|
u_int32_t i ;
|
|
|
|
i = (id->dst_ip) ^ (id->src_ip) ^ (id->dst_port) ^ (id->src_port);
|
|
i &= (curr_dyn_buckets - 1) ;
|
|
return i ;
|
|
}
|
|
|
|
/**
|
|
* unlink a dynamic rule from a chain. prev is a pointer to
|
|
* the previous one, q is a pointer to the rule to delete,
|
|
* head is a pointer to the head of the queue.
|
|
* Modifies q and potentially also head.
|
|
*/
|
|
#define UNLINK_DYN_RULE(prev, head, q) { \
|
|
struct ipfw_dyn_rule *old_q = q; \
|
|
\
|
|
/* remove a refcount to the parent */ \
|
|
if (q->dyn_type == DYN_LIMIT) \
|
|
q->parent->count--; \
|
|
DEB(printf("-- unlink entry 0x%08x %d -> 0x%08x %d, %d left\n", \
|
|
(q->id.src_ip), (q->id.src_port), \
|
|
(q->id.dst_ip), (q->id.dst_port), dyn_count-1 ); ) \
|
|
if (prev != NULL) \
|
|
prev->next = q = q->next ; \
|
|
else \
|
|
ipfw_dyn_v[i] = q = q->next ; \
|
|
dyn_count-- ; \
|
|
free(old_q, M_IPFW); }
|
|
|
|
#define TIME_LEQ(a,b) ((int)((a)-(b)) <= 0)
|
|
/**
|
|
* Remove all dynamic rules pointing to a given rule, or all
|
|
* rules if rule == NULL. Second parameter is 1 if we want to
|
|
* delete unconditionally, otherwise only expired rules are removed.
|
|
*/
|
|
static void
|
|
remove_dyn_rule(struct ip_fw *rule, int force)
|
|
{
|
|
struct ipfw_dyn_rule *prev, *q;
|
|
int i, pass, max_pass ;
|
|
static u_int32_t last_remove = 0 ;
|
|
|
|
if (ipfw_dyn_v == NULL || dyn_count == 0)
|
|
return ;
|
|
/* do not expire more than once per second, it is useless */
|
|
if (force == 0 && last_remove == time_second)
|
|
return ;
|
|
last_remove = time_second ;
|
|
|
|
/*
|
|
* because DYN_LIMIT refer to parent rules, during the first pass only
|
|
* remove child and mark any pending LIMIT_PARENT, and remove
|
|
* them in a second pass.
|
|
*/
|
|
for (pass = max_pass = 0; pass <= max_pass ; pass++ ) {
|
|
for (i = 0 ; i < curr_dyn_buckets ; i++) {
|
|
for (prev=NULL, q = ipfw_dyn_v[i] ; q ; ) {
|
|
/*
|
|
* logic can become complex here, so we split tests.
|
|
* First, test if we match any rule,
|
|
* then make sure the rule is expired or we want to kill it,
|
|
* and possibly more in the future.
|
|
*/
|
|
int zap = ( rule == NULL || rule == q->rule);
|
|
if (zap)
|
|
zap = force || TIME_LEQ( q->expire , time_second );
|
|
/* do not zap parent in first pass, record we need a second pass */
|
|
if (q->dyn_type == DYN_LIMIT_PARENT) {
|
|
max_pass = 1; /* we need a second pass */
|
|
if (zap == 1 && (pass == 0 || q->count != 0) ) {
|
|
zap = 0 ;
|
|
if (pass == 1) /* should not happen */
|
|
printf("OUCH! cannot remove rule, count %d\n",
|
|
q->count);
|
|
}
|
|
}
|
|
if (zap) {
|
|
UNLINK_DYN_RULE(prev, ipfw_dyn_v[i], q);
|
|
} else {
|
|
prev = q ;
|
|
q = q->next ;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
#define EXPIRE_DYN_CHAIN(rule) remove_dyn_rule(rule, 0 /* expired ones */)
|
|
#define EXPIRE_DYN_CHAINS() remove_dyn_rule(NULL, 0 /* expired ones */)
|
|
#define DELETE_DYN_CHAIN(rule) remove_dyn_rule(rule, 1 /* force removal */)
|
|
#define DELETE_DYN_CHAINS() remove_dyn_rule(NULL, 1 /* force removal */)
|
|
|
|
/**
|
|
* lookup a dynamic rule.
|
|
*/
|
|
static struct ipfw_dyn_rule *
|
|
lookup_dyn_rule(struct ipfw_flow_id *pkt, int *match_direction)
|
|
{
|
|
/*
|
|
* stateful ipfw extensions.
|
|
* Lookup into dynamic session queue
|
|
*/
|
|
struct ipfw_dyn_rule *prev, *q ;
|
|
int i, dir = 0;
|
|
#define MATCH_FORWARD 1
|
|
|
|
if (ipfw_dyn_v == NULL)
|
|
return NULL ;
|
|
i = hash_packet( pkt );
|
|
for (prev=NULL, q = ipfw_dyn_v[i] ; q != NULL ; ) {
|
|
if (q->dyn_type == DYN_LIMIT_PARENT)
|
|
goto next;
|
|
if (TIME_LEQ( q->expire , time_second ) ) { /* expire entry */
|
|
UNLINK_DYN_RULE(prev, ipfw_dyn_v[i], q);
|
|
continue;
|
|
}
|
|
if ( pkt->proto == q->id.proto) {
|
|
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 ;
|
|
goto found ;
|
|
}
|
|
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 = 0 ; /* reverse match */
|
|
goto found ;
|
|
}
|
|
}
|
|
next:
|
|
prev = q ;
|
|
q = q->next ;
|
|
}
|
|
return NULL ; /* clearly not found */
|
|
found:
|
|
if ( prev != NULL) { /* found and not in front */
|
|
prev->next = q->next ;
|
|
q->next = ipfw_dyn_v[i] ;
|
|
ipfw_dyn_v[i] = q ;
|
|
}
|
|
if (pkt->proto == IPPROTO_TCP) {
|
|
/* update state according to flags */
|
|
u_char flags = pkt->flags & (TH_FIN|TH_SYN|TH_RST);
|
|
q->state |= (dir == MATCH_FORWARD ) ? flags : (flags << 8);
|
|
switch (q->state) {
|
|
case TH_SYN :
|
|
/* opening */
|
|
q->expire = time_second + dyn_syn_lifetime ;
|
|
break ;
|
|
case TH_SYN | (TH_SYN << 8) :
|
|
/* move to established */
|
|
q->expire = time_second + dyn_ack_lifetime ;
|
|
break ;
|
|
case TH_SYN | (TH_SYN << 8) | TH_FIN :
|
|
case TH_SYN | (TH_SYN << 8) | (TH_FIN << 8) :
|
|
/* one side tries to close */
|
|
q->expire = time_second + dyn_ack_lifetime ;
|
|
break ;
|
|
case TH_SYN | (TH_SYN << 8) | TH_FIN | (TH_FIN << 8) :
|
|
/* both sides closed */
|
|
q->expire = time_second + 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
|
|
q->expire = time_second + dyn_rst_lifetime ;
|
|
break ;
|
|
}
|
|
} else if (pkt->proto == IPPROTO_UDP) {
|
|
q->expire = time_second + dyn_udp_lifetime ;
|
|
} else {
|
|
/* other protocols */
|
|
q->expire = time_second + dyn_short_lifetime ;
|
|
}
|
|
if (match_direction)
|
|
*match_direction = dir ;
|
|
return q ;
|
|
}
|
|
|
|
/**
|
|
* Install state of type 'type' for a dynamic session.
|
|
* The hash table contains two type of rules:
|
|
* - regular rules (DYN_KEEP_STATE)
|
|
* - rules for sessions with limited number of sess per user
|
|
* (DYN_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 (DYN_LIMIT_PARENT).
|
|
*/
|
|
|
|
static struct ipfw_dyn_rule *
|
|
add_dyn_rule(struct ipfw_flow_id *id, u_int8_t dyn_type, struct ip_fw *rule)
|
|
{
|
|
struct ipfw_dyn_rule *r ;
|
|
|
|
int i ;
|
|
if (ipfw_dyn_v == NULL ||
|
|
(dyn_count == 0 && dyn_buckets != curr_dyn_buckets)) {
|
|
/* try reallocation, make sure we have a power of 2 */
|
|
u_int32_t i = dyn_buckets ;
|
|
while ( i > 0 && (i & 1) == 0 )
|
|
i >>= 1 ;
|
|
if (i != 1) /* not a power of 2 */
|
|
dyn_buckets = curr_dyn_buckets ; /* reset */
|
|
else {
|
|
curr_dyn_buckets = dyn_buckets ;
|
|
if (ipfw_dyn_v != NULL)
|
|
free(ipfw_dyn_v, M_IPFW);
|
|
ipfw_dyn_v = malloc(curr_dyn_buckets * sizeof r,
|
|
M_IPFW, M_DONTWAIT | M_ZERO);
|
|
if (ipfw_dyn_v == NULL)
|
|
return NULL; /* failed ! */
|
|
}
|
|
}
|
|
i = hash_packet(id);
|
|
|
|
r = malloc(sizeof *r, M_IPFW, M_DONTWAIT | M_ZERO);
|
|
if (r == NULL) {
|
|
printf ("sorry cannot allocate state\n");
|
|
return NULL ;
|
|
}
|
|
|
|
/* increase refcount on parent, and set pointer */
|
|
if (dyn_type == DYN_LIMIT) {
|
|
struct ipfw_dyn_rule *parent = (struct ipfw_dyn_rule *)rule;
|
|
if ( parent->dyn_type != DYN_LIMIT_PARENT)
|
|
panic("invalid parent");
|
|
parent->count++ ;
|
|
r->parent = parent ;
|
|
rule = parent->rule;
|
|
}
|
|
|
|
r->id = *id ;
|
|
r->expire = time_second + dyn_syn_lifetime ;
|
|
r->rule = rule ;
|
|
r->dyn_type = dyn_type ;
|
|
r->pcnt = r->bcnt = 0 ;
|
|
r->count = 0 ;
|
|
|
|
r->bucket = i ;
|
|
r->next = ipfw_dyn_v[i] ;
|
|
ipfw_dyn_v[i] = r ;
|
|
dyn_count++ ;
|
|
DEB(printf("-- add entry 0x%08x %d -> 0x%08x %d, total %d\n",
|
|
(r->id.src_ip), (r->id.src_port),
|
|
(r->id.dst_ip), (r->id.dst_port),
|
|
dyn_count ); )
|
|
return r;
|
|
}
|
|
|
|
/**
|
|
* lookup dynamic parent rule using pkt and rule as search keys.
|
|
* If the lookup fails, then install one.
|
|
*/
|
|
static struct ipfw_dyn_rule *
|
|
lookup_dyn_parent(struct ipfw_flow_id *pkt, struct ip_fw *rule)
|
|
{
|
|
struct ipfw_dyn_rule *q;
|
|
int i;
|
|
|
|
if (ipfw_dyn_v) {
|
|
i = hash_packet( pkt );
|
|
for (q = ipfw_dyn_v[i] ; q != NULL ; q=q->next)
|
|
if (q->dyn_type == DYN_LIMIT_PARENT && rule == q->rule &&
|
|
pkt->proto == q->id.proto &&
|
|
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) {
|
|
q->expire = time_second + dyn_short_lifetime ;
|
|
DEB(printf("lookup_dyn_parent found 0x%p\n", q);)
|
|
return q;
|
|
}
|
|
}
|
|
return add_dyn_rule(pkt, DYN_LIMIT_PARENT, rule);
|
|
}
|
|
|
|
/*
|
|
* Install dynamic state.
|
|
* There are different types of dynamic rules which can be installed.
|
|
* The type is in rule->dyn_type.
|
|
* Type 0 (default) is a bidirectional rule
|
|
*
|
|
* Returns 1 (failure) if state is not installed because of errors or because
|
|
* session limitations are enforced.
|
|
*/
|
|
static int
|
|
install_state(struct ip_fw *rule)
|
|
{
|
|
struct ipfw_dyn_rule *q ;
|
|
static int last_log ;
|
|
|
|
u_int8_t type = rule->dyn_type ;
|
|
|
|
DEB(printf("-- install state type %d 0x%08x %u -> 0x%08x %u\n",
|
|
type,
|
|
(last_pkt.src_ip), (last_pkt.src_port),
|
|
(last_pkt.dst_ip), (last_pkt.dst_port) );)
|
|
|
|
q = lookup_dyn_rule(&last_pkt, NULL) ;
|
|
if (q != NULL) { /* should never occur */
|
|
if (last_log != time_second) {
|
|
last_log = time_second ;
|
|
printf(" entry already present, done\n");
|
|
}
|
|
return 0 ;
|
|
}
|
|
if (dyn_count >= dyn_max) /* try remove old ones... */
|
|
EXPIRE_DYN_CHAINS();
|
|
if (dyn_count >= dyn_max) {
|
|
if (last_log != time_second) {
|
|
last_log = time_second ;
|
|
printf(" Too many dynamic rules, sorry\n");
|
|
}
|
|
return 1; /* cannot install, notify caller */
|
|
}
|
|
|
|
switch (type) {
|
|
case DYN_KEEP_STATE: /* bidir rule */
|
|
add_dyn_rule(&last_pkt, DYN_KEEP_STATE, rule);
|
|
break ;
|
|
case DYN_LIMIT: /* limit number of sessions */
|
|
{
|
|
u_int16_t limit_mask = rule->limit_mask ;
|
|
u_int16_t conn_limit = rule->conn_limit ;
|
|
struct ipfw_flow_id id;
|
|
struct ipfw_dyn_rule *parent;
|
|
|
|
DEB(printf("installing dyn-limit rule %d\n", conn_limit);)
|
|
|
|
id.dst_ip = id.src_ip = 0;
|
|
id.dst_port = id.src_port = 0 ;
|
|
id.proto = last_pkt.proto ;
|
|
|
|
if (limit_mask & DYN_SRC_ADDR)
|
|
id.src_ip = last_pkt.src_ip;
|
|
if (limit_mask & DYN_DST_ADDR)
|
|
id.dst_ip = last_pkt.dst_ip;
|
|
if (limit_mask & DYN_SRC_PORT)
|
|
id.src_port = last_pkt.src_port;
|
|
if (limit_mask & DYN_DST_PORT)
|
|
id.dst_port = last_pkt.dst_port;
|
|
parent = lookup_dyn_parent(&id, rule);
|
|
if (parent == NULL) {
|
|
printf("add parent failed\n");
|
|
return 1;
|
|
}
|
|
if (parent->count >= conn_limit) {
|
|
EXPIRE_DYN_CHAIN(rule); /* try to expire some */
|
|
if (parent->count >= conn_limit) {
|
|
printf("drop session, too many entries\n");
|
|
return 1;
|
|
}
|
|
}
|
|
add_dyn_rule(&last_pkt, DYN_LIMIT, (struct ip_fw *)parent);
|
|
}
|
|
break ;
|
|
default:
|
|
printf("unknown dynamic rule type %u\n", type);
|
|
return 1 ;
|
|
}
|
|
lookup_dyn_rule(&last_pkt, NULL) ; /* XXX just set the lifetime */
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* given an ip_fw *, lookup_next_rule will return a pointer
|
|
* of the same type to the next one. This can be either the jump
|
|
* target (for skipto instructions) or the next one in the list (in
|
|
* all other cases including a missing jump target).
|
|
* Backward jumps are not allowed, so start looking from the next
|
|
* rule...
|
|
*/
|
|
static struct ip_fw * lookup_next_rule(struct ip_fw *me);
|
|
|
|
static struct ip_fw *
|
|
lookup_next_rule(struct ip_fw *me)
|
|
{
|
|
struct ip_fw *rule ;
|
|
int rulenum = me->fw_skipto_rule ; /* guess... */
|
|
|
|
if ( (me->fw_flg & IP_FW_F_COMMAND) == IP_FW_F_SKIPTO )
|
|
for (rule = LIST_NEXT(me,next); rule ; rule = LIST_NEXT(rule,next))
|
|
if (rule->fw_number >= rulenum)
|
|
return rule ;
|
|
return LIST_NEXT(me,next) ; /* failure or not a skipto */
|
|
}
|
|
|
|
/*
|
|
* Parameters:
|
|
*
|
|
* pip Pointer to packet header (struct ip **)
|
|
* hlen Packet header length
|
|
* oif Outgoing interface, or NULL if packet is incoming
|
|
* *cookie Skip up to the first rule past this rule number;
|
|
* upon return, non-zero port number for divert or tee.
|
|
* Special case: cookie == NULL on input for bridging.
|
|
* *m The packet; we set to NULL when/if we nuke it.
|
|
* *flow_id pointer to the last matching rule (in/out)
|
|
* *next_hop socket we are forwarding to (in/out).
|
|
*
|
|
* Return value:
|
|
*
|
|
* IP_FW_PORT_DENY_FLAG the packet must be dropped.
|
|
* 0 The packet is to be accepted and routed normally OR
|
|
* the packet was denied/rejected and has been dropped;
|
|
* in the latter case, *m is equal to NULL upon return.
|
|
* port Divert the packet to port, with these caveats:
|
|
*
|
|
* - If IP_FW_PORT_TEE_FLAG is set, tee the packet instead
|
|
* of diverting it (ie, 'ipfw tee').
|
|
*
|
|
* - If IP_FW_PORT_DYNT_FLAG is set, interpret the lower
|
|
* 16 bits as a dummynet pipe number instead of diverting
|
|
*/
|
|
|
|
static int
|
|
ip_fw_chk(struct ip **pip, int hlen,
|
|
struct ifnet *oif, u_int16_t *cookie, struct mbuf **m,
|
|
struct ip_fw **flow_id,
|
|
struct sockaddr_in **next_hop)
|
|
{
|
|
struct ip_fw *f = NULL; /* matching rule */
|
|
struct ip *ip = *pip;
|
|
struct ifnet *const rif = (*m)->m_pkthdr.rcvif;
|
|
struct ifnet *tif;
|
|
|
|
u_short offset = 0 ;
|
|
u_short src_port = 0, dst_port = 0;
|
|
struct in_addr src_ip, dst_ip; /* XXX */
|
|
u_int8_t proto= 0, flags = 0 ; /* XXX */
|
|
u_int16_t skipto, bridgeCookie;
|
|
u_int16_t ip_len;
|
|
|
|
int dyn_checked = 0 ; /* set after dyn.rules have been checked. */
|
|
int direction = MATCH_FORWARD ; /* dirty trick... */
|
|
struct ipfw_dyn_rule *q = NULL ;
|
|
|
|
/* Special hack for bridging (as usual) */
|
|
if (cookie == NULL) {
|
|
bridgeCookie = 0;
|
|
cookie = &bridgeCookie;
|
|
#define BRIDGED (cookie == &bridgeCookie)
|
|
hlen = ip->ip_hl << 2;
|
|
}
|
|
|
|
/* Grab and reset cookie */
|
|
skipto = *cookie;
|
|
*cookie = 0;
|
|
|
|
#define PULLUP_TO(len) do { \
|
|
if ((*m)->m_len < (len)) { \
|
|
ip = NULL ; \
|
|
if ((*m = m_pullup(*m, (len))) == 0) \
|
|
goto bogusfrag; \
|
|
ip = mtod(*m, struct ip *); \
|
|
*pip = ip; \
|
|
} \
|
|
} while (0)
|
|
|
|
/*
|
|
* Collect parameters into local variables for faster matching.
|
|
*/
|
|
proto = ip->ip_p;
|
|
src_ip = ip->ip_src;
|
|
dst_ip = ip->ip_dst;
|
|
if (0 && BRIDGED) { /* not yet... */
|
|
offset = (ntohs(ip->ip_off) & IP_OFFMASK);
|
|
ip_len = ntohs(ip->ip_len);
|
|
} else {
|
|
offset = (ip->ip_off & IP_OFFMASK);
|
|
ip_len = ip->ip_len;
|
|
}
|
|
if (offset == 0) {
|
|
switch (proto) {
|
|
case IPPROTO_TCP : {
|
|
struct tcphdr *tcp;
|
|
|
|
PULLUP_TO(hlen + sizeof(struct tcphdr));
|
|
tcp =(struct tcphdr *)((u_int32_t *)ip + ip->ip_hl);
|
|
dst_port = tcp->th_dport ;
|
|
src_port = tcp->th_sport ;
|
|
flags = tcp->th_flags ;
|
|
}
|
|
break ;
|
|
|
|
case IPPROTO_UDP : {
|
|
struct udphdr *udp;
|
|
|
|
PULLUP_TO(hlen + sizeof(struct udphdr));
|
|
udp =(struct udphdr *)((u_int32_t *)ip + ip->ip_hl);
|
|
dst_port = udp->uh_dport ;
|
|
src_port = udp->uh_sport ;
|
|
}
|
|
break;
|
|
|
|
case IPPROTO_ICMP:
|
|
PULLUP_TO(hlen + 4); /* type, code and checksum. */
|
|
flags = ((struct icmp *)
|
|
((u_int32_t *)ip + ip->ip_hl))->icmp_type ;
|
|
break ;
|
|
|
|
default :
|
|
break;
|
|
}
|
|
}
|
|
#undef PULLUP_TO
|
|
last_pkt.src_ip = ntohl(src_ip.s_addr);
|
|
last_pkt.dst_ip = ntohl(dst_ip.s_addr);
|
|
last_pkt.proto = proto;
|
|
last_pkt.src_port = ntohs(src_port);
|
|
last_pkt.dst_port = ntohs(dst_port);
|
|
last_pkt.flags = flags;
|
|
|
|
if (*flow_id) {
|
|
/*
|
|
* Packet has already been tagged. Look for the next rule
|
|
* to restart processing.
|
|
*/
|
|
if (fw_one_pass) /* just accept if fw_one_pass is set */
|
|
return 0;
|
|
|
|
f = (*flow_id)->next_rule_ptr ;
|
|
if (f == NULL)
|
|
f = (*flow_id)->next_rule_ptr = lookup_next_rule(*flow_id);
|
|
if (f == NULL)
|
|
goto dropit;
|
|
} else {
|
|
/*
|
|
* Go down the list, looking for enlightment.
|
|
* If we've been asked to start at a given rule, do so.
|
|
*/
|
|
f = LIST_FIRST(&ip_fw_chain_head);
|
|
if (skipto != 0) {
|
|
if (skipto >= IPFW_DEFAULT_RULE)
|
|
goto dropit;
|
|
while (f && f->fw_number <= skipto)
|
|
f = LIST_NEXT(f, next);
|
|
if (f == NULL)
|
|
goto dropit;
|
|
}
|
|
}
|
|
|
|
for (; f; f = LIST_NEXT(f, next)) {
|
|
again:
|
|
if (f->fw_number == IPFW_DEFAULT_RULE)
|
|
goto got_match ;
|
|
|
|
/*
|
|
* dynamic rules are checked at the first keep-state or
|
|
* check-state occurrence.
|
|
*/
|
|
if (f->fw_flg & (IP_FW_F_KEEP_S|IP_FW_F_CHECK_S) &&
|
|
dyn_checked == 0 ) {
|
|
dyn_checked = 1 ;
|
|
q = lookup_dyn_rule(&last_pkt, &direction);
|
|
if (q != NULL) {
|
|
DEB(printf("-- dynamic match 0x%08x %d %s 0x%08x %d\n",
|
|
(q->id.src_ip), (q->id.src_port),
|
|
(direction == MATCH_FORWARD ? "-->" : "<--"),
|
|
(q->id.dst_ip), (q->id.dst_port) ); )
|
|
f = q->rule ;
|
|
q->pcnt++ ;
|
|
q->bcnt += ip_len;
|
|
goto got_match ; /* random not allowed here */
|
|
}
|
|
/* if this was a check-only rule, continue with next */
|
|
if (f->fw_flg & IP_FW_F_CHECK_S)
|
|
continue ;
|
|
}
|
|
|
|
/* Check if rule only valid for bridged packets */
|
|
if ((f->fw_flg & IP_FW_BRIDGED) != 0 && !(BRIDGED))
|
|
continue;
|
|
|
|
if (oif) {
|
|
/* Check direction outbound */
|
|
if (!(f->fw_flg & IP_FW_F_OUT))
|
|
continue;
|
|
} else {
|
|
/* Check direction inbound */
|
|
if (!(f->fw_flg & IP_FW_F_IN))
|
|
continue;
|
|
}
|
|
|
|
/* Fragments */
|
|
if ((f->fw_flg & IP_FW_F_FRAG) && offset == 0 )
|
|
continue;
|
|
|
|
if (f->fw_flg & IP_FW_F_SME) {
|
|
INADDR_TO_IFP(src_ip, tif);
|
|
if (tif == NULL)
|
|
continue;
|
|
}
|
|
if (f->fw_flg & IP_FW_F_DME) {
|
|
INADDR_TO_IFP(dst_ip, tif);
|
|
if (tif == NULL)
|
|
continue;
|
|
}
|
|
/* If src-addr doesn't match, not this rule. */
|
|
if (((f->fw_flg & IP_FW_F_INVSRC) != 0) ^ ((src_ip.s_addr
|
|
& f->fw_smsk.s_addr) != f->fw_src.s_addr))
|
|
continue;
|
|
|
|
/* If dest-addr doesn't match, not this rule. */
|
|
if (((f->fw_flg & IP_FW_F_INVDST) != 0) ^ ((dst_ip.s_addr
|
|
& f->fw_dmsk.s_addr) != f->fw_dst.s_addr))
|
|
continue;
|
|
|
|
/* Interface check */
|
|
if ((f->fw_flg & IF_FW_F_VIAHACK) == IF_FW_F_VIAHACK) {
|
|
struct ifnet *const iface = oif ? oif : rif;
|
|
|
|
/* Backwards compatibility hack for "via" */
|
|
if (!iface || !iface_match(iface,
|
|
&f->fw_in_if, f->fw_flg & IP_FW_F_OIFNAME))
|
|
continue;
|
|
} else {
|
|
/* Check receive interface */
|
|
if ((f->fw_flg & IP_FW_F_IIFACE)
|
|
&& (!rif || !iface_match(rif,
|
|
&f->fw_in_if, f->fw_flg & IP_FW_F_IIFNAME)))
|
|
continue;
|
|
/* Check outgoing interface */
|
|
if ((f->fw_flg & IP_FW_F_OIFACE)
|
|
&& (!oif || !iface_match(oif,
|
|
&f->fw_out_if, f->fw_flg & IP_FW_F_OIFNAME)))
|
|
continue;
|
|
}
|
|
|
|
/* Check IP header values */
|
|
if (f->fw_ipflg & IP_FW_IF_IPOPT && !ipopts_match(ip, f))
|
|
continue;
|
|
if (f->fw_ipflg & IP_FW_IF_IPLEN && f->fw_iplen != ip_len)
|
|
continue;
|
|
if (f->fw_ipflg & IP_FW_IF_IPID && f->fw_ipid != ntohs(ip->ip_id))
|
|
continue;
|
|
if (f->fw_ipflg & IP_FW_IF_IPPRE &&
|
|
(f->fw_iptos & 0xe0) != (ip->ip_tos & 0xe0))
|
|
continue;
|
|
if (f->fw_ipflg & IP_FW_IF_IPTOS && !iptos_match(ip, f))
|
|
continue;
|
|
if (f->fw_ipflg & IP_FW_IF_IPTTL && f->fw_ipttl != ip->ip_ttl)
|
|
continue;
|
|
if (f->fw_ipflg & IP_FW_IF_IPVER && f->fw_ipver != ip->ip_v)
|
|
continue;
|
|
|
|
/* Check protocol; if wildcard, and no [ug]id, match */
|
|
if (f->fw_prot == IPPROTO_IP) {
|
|
if (!(f->fw_flg & (IP_FW_F_UID|IP_FW_F_GID)))
|
|
goto rnd_then_got_match;
|
|
} else
|
|
/* If different, don't match */
|
|
if (proto != f->fw_prot)
|
|
continue;
|
|
|
|
/* Protocol specific checks for uid only */
|
|
if (f->fw_flg & (IP_FW_F_UID|IP_FW_F_GID)) {
|
|
switch (proto) {
|
|
case IPPROTO_TCP:
|
|
{
|
|
struct inpcb *P;
|
|
|
|
if (offset == 1) /* cf. RFC 1858 */
|
|
goto bogusfrag;
|
|
if (offset != 0)
|
|
continue;
|
|
|
|
if (oif)
|
|
P = in_pcblookup_hash(&tcbinfo, dst_ip,
|
|
dst_port, src_ip, src_port, 0,
|
|
oif);
|
|
else
|
|
P = in_pcblookup_hash(&tcbinfo, src_ip,
|
|
src_port, dst_ip, dst_port, 0,
|
|
NULL);
|
|
|
|
if (P && P->inp_socket) {
|
|
if (f->fw_flg & IP_FW_F_UID) {
|
|
if (socheckuid(P->inp_socket, f->fw_uid))
|
|
continue;
|
|
} else if (!groupmember(f->fw_gid,
|
|
P->inp_socket->so_cred))
|
|
continue;
|
|
} else
|
|
continue;
|
|
break;
|
|
}
|
|
|
|
case IPPROTO_UDP:
|
|
{
|
|
struct inpcb *P;
|
|
|
|
if (offset != 0)
|
|
continue;
|
|
|
|
if (oif)
|
|
P = in_pcblookup_hash(&udbinfo, dst_ip,
|
|
dst_port, src_ip, src_port, 1,
|
|
oif);
|
|
else
|
|
P = in_pcblookup_hash(&udbinfo, src_ip,
|
|
src_port, dst_ip, dst_port, 1,
|
|
NULL);
|
|
|
|
if (P && P->inp_socket) {
|
|
if (f->fw_flg & IP_FW_F_UID) {
|
|
if (socheckuid(P->inp_socket, f->fw_uid))
|
|
continue;
|
|
} else if (!groupmember(f->fw_gid,
|
|
P->inp_socket->so_cred))
|
|
continue;
|
|
} else
|
|
continue;
|
|
break;
|
|
}
|
|
|
|
default:
|
|
continue;
|
|
}
|
|
}
|
|
|
|
/* Protocol specific checks */
|
|
switch (proto) {
|
|
case IPPROTO_TCP:
|
|
{
|
|
struct tcphdr *tcp;
|
|
|
|
if (offset == 1) /* cf. RFC 1858 */
|
|
goto bogusfrag;
|
|
if (offset != 0) {
|
|
/*
|
|
* TCP flags and ports aren't available in this
|
|
* packet -- if this rule specified either one,
|
|
* we consider the rule a non-match.
|
|
*/
|
|
if (IP_FW_HAVEPORTS(f) != 0 ||
|
|
f->fw_ipflg & IP_FW_IF_TCPMSK)
|
|
continue;
|
|
|
|
break;
|
|
}
|
|
tcp = (struct tcphdr *) ((u_int32_t *)ip + ip->ip_hl);
|
|
|
|
if (f->fw_ipflg & IP_FW_IF_TCPOPT && !tcpopts_match(tcp, f))
|
|
continue;
|
|
if (((f->fw_ipflg & IP_FW_IF_TCPFLG) ||
|
|
(f->fw_ipflg & IP_FW_IF_TCPEST)) &&
|
|
!tcpflg_match(tcp, f))
|
|
continue;
|
|
if (f->fw_ipflg & IP_FW_IF_TCPSEQ && tcp->th_seq != f->fw_tcpseq)
|
|
continue;
|
|
if (f->fw_ipflg & IP_FW_IF_TCPACK && tcp->th_ack != f->fw_tcpack)
|
|
continue;
|
|
if (f->fw_ipflg & IP_FW_IF_TCPWIN && tcp->th_win != f->fw_tcpwin)
|
|
continue;
|
|
goto check_ports;
|
|
}
|
|
|
|
case IPPROTO_UDP:
|
|
if (offset != 0) {
|
|
/*
|
|
* Port specification is unavailable -- if this
|
|
* rule specifies a port, we consider the rule
|
|
* a non-match.
|
|
*/
|
|
if (IP_FW_HAVEPORTS(f) )
|
|
continue;
|
|
|
|
break;
|
|
}
|
|
check_ports:
|
|
if (!port_match(&f->fw_uar.fw_pts[0],
|
|
IP_FW_GETNSRCP(f), ntohs(src_port),
|
|
f->fw_flg & IP_FW_F_SRNG,
|
|
f->fw_flg & IP_FW_F_SMSK))
|
|
continue;
|
|
if (!port_match(&f->fw_uar.fw_pts[IP_FW_GETNSRCP(f)],
|
|
IP_FW_GETNDSTP(f), ntohs(dst_port),
|
|
f->fw_flg & IP_FW_F_DRNG,
|
|
f->fw_flg & IP_FW_F_DMSK))
|
|
continue;
|
|
break;
|
|
|
|
case IPPROTO_ICMP:
|
|
{
|
|
struct icmp *icmp;
|
|
|
|
if (offset != 0) /* Type isn't valid */
|
|
break;
|
|
icmp = (struct icmp *) ((u_int32_t *)ip + ip->ip_hl);
|
|
if (!icmptype_match(icmp, f))
|
|
continue;
|
|
break;
|
|
}
|
|
|
|
default:
|
|
break;
|
|
|
|
bogusfrag:
|
|
if (fw_verbose) {
|
|
if (ip != NULL)
|
|
ipfw_report(NULL, ip, offset, ip_len, rif, oif);
|
|
else
|
|
printf("pullup failed\n");
|
|
}
|
|
goto dropit;
|
|
|
|
}
|
|
|
|
rnd_then_got_match:
|
|
if ( f->dont_match_prob && random() < f->dont_match_prob )
|
|
continue ;
|
|
got_match:
|
|
/*
|
|
* If not a dynamic match (q == NULL) and keep-state, install
|
|
* a new dynamic entry.
|
|
*/
|
|
if (q == NULL && f->fw_flg & IP_FW_F_KEEP_S) {
|
|
if (install_state(f)) /* error or limit violation */
|
|
goto dropit;
|
|
}
|
|
/* Update statistics */
|
|
f->fw_pcnt += 1;
|
|
f->fw_bcnt += ip_len;
|
|
f->timestamp = time_second;
|
|
|
|
/* Log to console if desired */
|
|
if ((f->fw_flg & IP_FW_F_PRN) && fw_verbose)
|
|
ipfw_report(f, ip, offset, ip_len, rif, oif);
|
|
|
|
/* Take appropriate action */
|
|
switch (f->fw_flg & IP_FW_F_COMMAND) {
|
|
case IP_FW_F_ACCEPT:
|
|
return(0);
|
|
case IP_FW_F_COUNT:
|
|
continue;
|
|
#ifdef IPDIVERT
|
|
case IP_FW_F_DIVERT:
|
|
*cookie = f->fw_number;
|
|
return(f->fw_divert_port);
|
|
case IP_FW_F_TEE:
|
|
*cookie = f->fw_number;
|
|
return(f->fw_divert_port | IP_FW_PORT_TEE_FLAG);
|
|
#endif
|
|
case IP_FW_F_SKIPTO: /* XXX check */
|
|
if (f->next_rule_ptr == NULL)
|
|
f->next_rule_ptr = lookup_next_rule(f) ;
|
|
f = f->next_rule_ptr;
|
|
if (!f)
|
|
goto dropit;
|
|
goto again ;
|
|
|
|
case IP_FW_F_PIPE:
|
|
case IP_FW_F_QUEUE:
|
|
*flow_id = f; /* XXX set flow id */
|
|
return(f->fw_pipe_nr | IP_FW_PORT_DYNT_FLAG);
|
|
#ifdef IPFIREWALL_FORWARD
|
|
case IP_FW_F_FWD:
|
|
/* Change the next-hop address for this packet.
|
|
* Initially we'll only worry about directly
|
|
* reachable next-hop's, but ultimately
|
|
* we will work out for next-hops that aren't
|
|
* direct the route we would take for it. We
|
|
* [cs]ould leave this latter problem to
|
|
* ip_output.c. We hope to high [name the abode of
|
|
* your favourite deity] that ip_output doesn't modify
|
|
* the new value of next_hop (which is dst there)
|
|
* XXX warning-- there is a dangerous reference here
|
|
* from next_hop to a field within the rule. If the
|
|
* rule is deleted, weird things might occur.
|
|
*/
|
|
if (next_hop != NULL /* Make sure, first... */
|
|
&& (q == NULL || direction == MATCH_FORWARD) )
|
|
*next_hop = &(f->fw_fwd_ip);
|
|
return(0); /* Allow the packet */
|
|
#endif
|
|
}
|
|
|
|
/* Deny/reject this packet using this rule */
|
|
break;
|
|
}
|
|
|
|
/* Rule IPFW_DEFAULT_RULE should always be there and match */
|
|
KASSERT(f != NULL, ("ip_fw: no chain"));
|
|
|
|
/*
|
|
* At this point, we're going to drop the packet.
|
|
* Send a reject notice if all of the following are true:
|
|
*
|
|
* - The packet matched a reject rule
|
|
* - The packet is not an ICMP packet, or is an ICMP query packet
|
|
* - The packet is not a multicast or broadcast packet
|
|
*/
|
|
if ((f->fw_flg & IP_FW_F_COMMAND) == IP_FW_F_REJECT
|
|
&& (proto != IPPROTO_ICMP || is_icmp_query(ip))
|
|
&& !((*m)->m_flags & (M_BCAST|M_MCAST))
|
|
&& !IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
|
|
switch (f->fw_reject_code) {
|
|
case IP_FW_REJECT_RST:
|
|
{
|
|
/* XXX warning, this code writes into the mbuf */
|
|
struct tcphdr *const tcp =
|
|
(struct tcphdr *) ((u_int32_t *)ip + ip->ip_hl);
|
|
struct tcpiphdr ti, *const tip = (struct tcpiphdr *) ip;
|
|
|
|
if (offset != 0 || (tcp->th_flags & TH_RST))
|
|
break;
|
|
ti.ti_i = *((struct ipovly *) ip);
|
|
ti.ti_t = *tcp;
|
|
bcopy(&ti, ip, sizeof(ti));
|
|
tip->ti_seq = ntohl(tip->ti_seq);
|
|
tip->ti_ack = ntohl(tip->ti_ack);
|
|
tip->ti_len = ip_len - hlen - (tip->ti_off << 2);
|
|
if (tcp->th_flags & TH_ACK) {
|
|
tcp_respond(NULL, (void *)ip, tcp, *m,
|
|
(tcp_seq)0, tcp->th_ack, TH_RST);
|
|
} else {
|
|
if (tcp->th_flags & TH_SYN)
|
|
tip->ti_len++;
|
|
tcp_respond(NULL, (void *)ip, tcp, *m,
|
|
tip->ti_seq + tip->ti_len,
|
|
(tcp_seq)0, TH_RST|TH_ACK);
|
|
}
|
|
*m = NULL;
|
|
break;
|
|
}
|
|
default: /* Send an ICMP unreachable using code */
|
|
icmp_error(*m, ICMP_UNREACH,
|
|
f->fw_reject_code, 0L, 0);
|
|
*m = NULL;
|
|
break;
|
|
}
|
|
}
|
|
|
|
dropit:
|
|
/*
|
|
* Finally, drop the packet.
|
|
*/
|
|
return(IP_FW_PORT_DENY_FLAG);
|
|
#undef BRIDGED
|
|
}
|
|
|
|
/*
|
|
* when a rule is added/deleted, zero the direct pointers within
|
|
* all firewall rules. These will be reconstructed on the fly
|
|
* as packets are matched.
|
|
* Must be called at splimp().
|
|
*/
|
|
static void
|
|
flush_rule_ptrs()
|
|
{
|
|
struct ip_fw *fcp ;
|
|
|
|
LIST_FOREACH(fcp, &ip_fw_chain_head, next) {
|
|
fcp->next_rule_ptr = NULL ;
|
|
}
|
|
}
|
|
|
|
static int
|
|
add_entry(struct ip_fw_head *head, struct ip_fw *rule)
|
|
{
|
|
struct ip_fw *ftmp, *fcp, *fcpl;
|
|
u_short nbr = 0;
|
|
int s;
|
|
|
|
ftmp = malloc(sizeof *ftmp, M_IPFW, M_DONTWAIT | M_ZERO);
|
|
if (!ftmp)
|
|
return (ENOSPC);
|
|
bcopy(rule, ftmp, sizeof(*ftmp));
|
|
|
|
ftmp->fw_in_if.fu_via_if.name[FW_IFNLEN - 1] = '\0';
|
|
ftmp->fw_pcnt = 0L;
|
|
ftmp->fw_bcnt = 0L;
|
|
ftmp->next_rule_ptr = NULL ;
|
|
ftmp->pipe_ptr = NULL ;
|
|
|
|
s = splimp();
|
|
|
|
if (LIST_FIRST(head) == 0) {
|
|
LIST_INSERT_HEAD(head, ftmp, next);
|
|
goto done;
|
|
}
|
|
|
|
/* If entry number is 0, find highest numbered rule and add 100 */
|
|
if (ftmp->fw_number == 0) {
|
|
LIST_FOREACH(fcp, head, next) {
|
|
if (fcp->fw_number != IPFW_DEFAULT_RULE)
|
|
nbr = fcp->fw_number;
|
|
else
|
|
break;
|
|
}
|
|
if (nbr < IPFW_DEFAULT_RULE - 100)
|
|
nbr += 100;
|
|
ftmp->fw_number = rule->fw_number = nbr;
|
|
}
|
|
|
|
/* Got a valid number; now insert it, keeping the list ordered */
|
|
fcpl = NULL ;
|
|
LIST_FOREACH(fcp, head, next) {
|
|
if (fcp->fw_number > ftmp->fw_number) {
|
|
if (fcpl) {
|
|
LIST_INSERT_AFTER(fcpl, ftmp, next);
|
|
} else {
|
|
LIST_INSERT_HEAD(head, ftmp, next);
|
|
}
|
|
break;
|
|
} else {
|
|
fcpl = fcp;
|
|
}
|
|
}
|
|
flush_rule_ptrs();
|
|
done:
|
|
static_count++;
|
|
splx(s);
|
|
DEB(printf("++ installed rule %d, static count now %d\n",
|
|
ftmp->fw_number, static_count);)
|
|
return (0);
|
|
}
|
|
|
|
/**
|
|
* free storage associated with a static rule entry (including
|
|
* dependent dynamic rules), and zeroes rule pointers to avoid
|
|
* dangling pointer dereferences.
|
|
* @return a pointer to the next entry.
|
|
* Must be called at splimp() and with a non-null argument.
|
|
*/
|
|
static struct ip_fw *
|
|
free_chain(struct ip_fw *fcp)
|
|
{
|
|
struct ip_fw *n;
|
|
|
|
n = LIST_NEXT(fcp, next);
|
|
DELETE_DYN_CHAIN(fcp);
|
|
LIST_REMOVE(fcp, next);
|
|
static_count--;
|
|
if (DUMMYNET_LOADED)
|
|
ip_dn_ruledel_ptr(fcp) ;
|
|
flush_rule_ptrs(); /* more efficient to do outside the loop */
|
|
free(fcp, M_IPFW);
|
|
return n;
|
|
}
|
|
|
|
/**
|
|
* remove all rules with given number.
|
|
*/
|
|
static int
|
|
del_entry(struct ip_fw_head *chainptr, u_short number)
|
|
{
|
|
struct ip_fw *rule;
|
|
|
|
if (number != IPFW_DEFAULT_RULE) {
|
|
LIST_FOREACH(rule, chainptr, next) {
|
|
if (rule->fw_number == number) {
|
|
int s ;
|
|
|
|
s = splimp(); /* prevent access to rules while removing */
|
|
while (rule && rule->fw_number == number)
|
|
rule = free_chain(rule);
|
|
/* XXX could move flush_rule_ptrs() here */
|
|
splx(s);
|
|
return 0 ;
|
|
}
|
|
}
|
|
}
|
|
return (EINVAL);
|
|
}
|
|
|
|
/**
|
|
* Reset some or all counters on firewall rules.
|
|
* @arg frwl is null to clear all entries, or contains a specific
|
|
* rule number.
|
|
* @arg log_only is 1 if we only want to reset logs, zero otherwise.
|
|
*/
|
|
|
|
static int
|
|
zero_entry(struct ip_fw *frwl, int log_only)
|
|
{
|
|
struct ip_fw *rule;
|
|
int s;
|
|
u_short number = 0 ;
|
|
char *msg ;
|
|
|
|
if (frwl == 0) {
|
|
s = splimp();
|
|
LIST_FOREACH(rule, &ip_fw_chain_head, next) {
|
|
if (log_only == 0) {
|
|
rule->fw_bcnt = rule->fw_pcnt = 0;
|
|
rule->timestamp = 0;
|
|
}
|
|
rule->fw_loghighest = rule->fw_pcnt+rule->fw_logamount;
|
|
}
|
|
splx(s);
|
|
msg = log_only ? "ipfw: All logging counts cleared.\n" :
|
|
"ipfw: Accounting cleared.\n";
|
|
} else {
|
|
int cleared = 0;
|
|
number = frwl->fw_number ;
|
|
/*
|
|
* It is possible to insert multiple chain entries with the
|
|
* same number, so we don't stop after finding the first
|
|
* match if zeroing a specific entry.
|
|
*/
|
|
LIST_FOREACH(rule, &ip_fw_chain_head, next)
|
|
if (number == rule->fw_number) {
|
|
s = splimp();
|
|
while (rule && number == rule->fw_number) {
|
|
if (log_only == 0) {
|
|
rule->fw_bcnt = rule->fw_pcnt = 0;
|
|
rule->timestamp = 0;
|
|
}
|
|
rule->fw_loghighest = rule->fw_pcnt+ rule->fw_logamount;
|
|
rule = LIST_NEXT(rule, next);
|
|
}
|
|
splx(s);
|
|
cleared = 1;
|
|
break;
|
|
}
|
|
if (!cleared) /* we did not find any matching rules */
|
|
return (EINVAL);
|
|
msg = log_only ? "ipfw: Entry %d logging count reset.\n" :
|
|
"ipfw: Entry %d cleared.\n";
|
|
}
|
|
if (fw_verbose)
|
|
log(LOG_SECURITY | LOG_NOTICE, msg, number);
|
|
return (0);
|
|
}
|
|
|
|
static int
|
|
check_ipfw_struct(struct ip_fw *frwl)
|
|
{
|
|
/* Check for invalid flag bits */
|
|
if ((frwl->fw_flg & ~IP_FW_F_MASK) != 0) {
|
|
dprintf(("%s undefined flag bits set (flags=%x)\n",
|
|
err_prefix, frwl->fw_flg));
|
|
return (EINVAL);
|
|
}
|
|
if (frwl->fw_flg == IP_FW_F_CHECK_S) {
|
|
/* check-state */
|
|
return 0 ;
|
|
}
|
|
/* Must apply to incoming or outgoing (or both) */
|
|
if (!(frwl->fw_flg & (IP_FW_F_IN | IP_FW_F_OUT))) {
|
|
dprintf(("%s neither in nor out\n", err_prefix));
|
|
return (EINVAL);
|
|
}
|
|
/* Empty interface name is no good */
|
|
if (((frwl->fw_flg & IP_FW_F_IIFNAME)
|
|
&& !*frwl->fw_in_if.fu_via_if.name)
|
|
|| ((frwl->fw_flg & IP_FW_F_OIFNAME)
|
|
&& !*frwl->fw_out_if.fu_via_if.name)) {
|
|
dprintf(("%s empty interface name\n", err_prefix));
|
|
return (EINVAL);
|
|
}
|
|
/* Sanity check interface matching */
|
|
if ((frwl->fw_flg & IF_FW_F_VIAHACK) == IF_FW_F_VIAHACK) {
|
|
; /* allow "via" backwards compatibility */
|
|
} else if ((frwl->fw_flg & IP_FW_F_IN)
|
|
&& (frwl->fw_flg & IP_FW_F_OIFACE)) {
|
|
dprintf(("%s outgoing interface check on incoming\n",
|
|
err_prefix));
|
|
return (EINVAL);
|
|
}
|
|
/* Sanity check port ranges */
|
|
if ((frwl->fw_flg & IP_FW_F_SRNG) && IP_FW_GETNSRCP(frwl) < 2) {
|
|
dprintf(("%s src range set but n_src_p=%d\n",
|
|
err_prefix, IP_FW_GETNSRCP(frwl)));
|
|
return (EINVAL);
|
|
}
|
|
if ((frwl->fw_flg & IP_FW_F_DRNG) && IP_FW_GETNDSTP(frwl) < 2) {
|
|
dprintf(("%s dst range set but n_dst_p=%d\n",
|
|
err_prefix, IP_FW_GETNDSTP(frwl)));
|
|
return (EINVAL);
|
|
}
|
|
if (IP_FW_GETNSRCP(frwl) + IP_FW_GETNDSTP(frwl) > IP_FW_MAX_PORTS) {
|
|
dprintf(("%s too many ports (%d+%d)\n",
|
|
err_prefix, IP_FW_GETNSRCP(frwl), IP_FW_GETNDSTP(frwl)));
|
|
return (EINVAL);
|
|
}
|
|
/*
|
|
* Protocols other than TCP/UDP don't use port range
|
|
*/
|
|
if ((frwl->fw_prot != IPPROTO_TCP) &&
|
|
(frwl->fw_prot != IPPROTO_UDP) &&
|
|
(IP_FW_GETNSRCP(frwl) || IP_FW_GETNDSTP(frwl))) {
|
|
dprintf(("%s port(s) specified for non TCP/UDP rule\n",
|
|
err_prefix));
|
|
return (EINVAL);
|
|
}
|
|
|
|
/*
|
|
* Rather than modify the entry to make such entries work,
|
|
* we reject this rule and require user level utilities
|
|
* to enforce whatever policy they deem appropriate.
|
|
*/
|
|
if ((frwl->fw_src.s_addr & (~frwl->fw_smsk.s_addr)) ||
|
|
(frwl->fw_dst.s_addr & (~frwl->fw_dmsk.s_addr))) {
|
|
dprintf(("%s rule never matches\n", err_prefix));
|
|
return (EINVAL);
|
|
}
|
|
|
|
if ((frwl->fw_flg & IP_FW_F_FRAG) &&
|
|
(frwl->fw_prot == IPPROTO_UDP || frwl->fw_prot == IPPROTO_TCP)) {
|
|
if (IP_FW_HAVEPORTS(frwl)) {
|
|
dprintf(("%s cannot mix 'frag' and ports\n", err_prefix));
|
|
return (EINVAL);
|
|
}
|
|
if (frwl->fw_prot == IPPROTO_TCP &&
|
|
frwl->fw_tcpf != frwl->fw_tcpnf) {
|
|
dprintf(("%s cannot mix 'frag' and TCP flags\n", err_prefix));
|
|
return (EINVAL);
|
|
}
|
|
}
|
|
|
|
if (frwl->fw_flg & (IP_FW_F_UID | IP_FW_F_GID)) {
|
|
if ((frwl->fw_prot != IPPROTO_TCP) &&
|
|
(frwl->fw_prot != IPPROTO_UDP) &&
|
|
(frwl->fw_prot != IPPROTO_IP)) {
|
|
dprintf(("%s cannot use uid/gid logic on non-TCP/UDP\n", err_prefix));
|
|
return (EINVAL);
|
|
}
|
|
}
|
|
|
|
/* Check command specific stuff */
|
|
switch (frwl->fw_flg & IP_FW_F_COMMAND) {
|
|
case IP_FW_F_REJECT:
|
|
if (frwl->fw_reject_code >= 0x100
|
|
&& !(frwl->fw_prot == IPPROTO_TCP
|
|
&& frwl->fw_reject_code == IP_FW_REJECT_RST)) {
|
|
dprintf(("%s unknown reject code\n", err_prefix));
|
|
return (EINVAL);
|
|
}
|
|
break;
|
|
#ifdef IPDIVERT
|
|
case IP_FW_F_DIVERT: /* Diverting to port zero is invalid */
|
|
case IP_FW_F_TEE:
|
|
#endif
|
|
case IP_FW_F_PIPE: /* pipe 0 is invalid */
|
|
case IP_FW_F_QUEUE: /* queue 0 is invalid */
|
|
if (frwl->fw_divert_port == 0) {
|
|
dprintf(("%s 0 is an invalid argument\n", err_prefix));
|
|
return (EINVAL);
|
|
}
|
|
break;
|
|
case IP_FW_F_DENY:
|
|
case IP_FW_F_ACCEPT:
|
|
case IP_FW_F_COUNT:
|
|
case IP_FW_F_SKIPTO:
|
|
#ifdef IPFIREWALL_FORWARD
|
|
case IP_FW_F_FWD:
|
|
#endif
|
|
break;
|
|
default:
|
|
dprintf(("%s invalid command\n", err_prefix));
|
|
return (EINVAL);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
ip_fw_ctl(struct sockopt *sopt)
|
|
{
|
|
int error, s;
|
|
size_t size;
|
|
struct ip_fw *fcp;
|
|
struct ip_fw frwl, *bp , *buf;
|
|
|
|
/*
|
|
* Disallow modifications in really-really secure mode, but still allow
|
|
* the logging counters to be reset.
|
|
*/
|
|
if (sopt->sopt_name == IP_FW_ADD ||
|
|
(sopt->sopt_dir == SOPT_SET && sopt->sopt_name != IP_FW_RESETLOG)) {
|
|
error = securelevel_ge(sopt->sopt_td->td_ucred, 3);
|
|
if (error)
|
|
return (error);
|
|
}
|
|
|
|
error = 0;
|
|
|
|
switch (sopt->sopt_name) {
|
|
case IP_FW_GET:
|
|
/*
|
|
* pass up a copy of the current rules. Static rules
|
|
* come first (the last of which has number 65535),
|
|
* followed by a possibly empty list of dynamic rule.
|
|
* The last dynamic rule has NULL in the "next" field.
|
|
*/
|
|
s = splimp();
|
|
/* size of static rules */
|
|
size = static_count * sizeof(struct ip_fw) ;
|
|
if (ipfw_dyn_v) /* add size of dyn.rules */
|
|
size += (dyn_count * sizeof(struct ipfw_dyn_rule));
|
|
|
|
/*
|
|
* XXX todo: if the user passes a short length to know how
|
|
* much room is needed, do not
|
|
* bother filling up the buffer, just jump to the
|
|
* sooptcopyout.
|
|
*/
|
|
buf = malloc(size, M_TEMP, M_WAITOK);
|
|
if (buf == 0) {
|
|
splx(s);
|
|
error = ENOBUFS;
|
|
break;
|
|
}
|
|
|
|
bp = buf ;
|
|
LIST_FOREACH(fcp, &ip_fw_chain_head, next) {
|
|
bcopy(fcp, bp, sizeof *fcp);
|
|
bp++;
|
|
}
|
|
if (ipfw_dyn_v) {
|
|
int i ;
|
|
struct ipfw_dyn_rule *p, *dst, *last = NULL ;
|
|
|
|
dst = (struct ipfw_dyn_rule *)bp ;
|
|
for (i = 0 ; i < curr_dyn_buckets ; i++ )
|
|
for ( p = ipfw_dyn_v[i] ; p != NULL ; p = p->next, dst++ ) {
|
|
bcopy(p, dst, sizeof *p);
|
|
(int)dst->rule = p->rule->fw_number ;
|
|
/*
|
|
* store a non-null value in "next". The userland
|
|
* code will interpret a NULL here as a marker
|
|
* for the last dynamic rule.
|
|
*/
|
|
dst->next = dst ;
|
|
last = dst ;
|
|
if (TIME_LEQ(dst->expire, time_second) )
|
|
dst->expire = 0 ;
|
|
else
|
|
dst->expire -= time_second ;
|
|
}
|
|
if (last != NULL)
|
|
last->next = NULL ; /* mark last dynamic rule */
|
|
}
|
|
splx(s);
|
|
|
|
error = sooptcopyout(sopt, buf, size);
|
|
free(buf, M_TEMP);
|
|
break;
|
|
|
|
case IP_FW_FLUSH:
|
|
/*
|
|
* Normally we cannot release the lock on each iteration.
|
|
* We could do it here only because we start from the head all
|
|
* the times so there is no risk of missing some entries.
|
|
* On the other hand, the risk is that we end up with
|
|
* a very inconsistent ruleset, so better keep the lock
|
|
* around the whole cycle.
|
|
*
|
|
* XXX this code can be improved by resetting the head of
|
|
* the list to point to the default rule, and then freeing
|
|
* the old list without the need for a lock.
|
|
*/
|
|
|
|
s = splimp();
|
|
while ( (fcp = LIST_FIRST(&ip_fw_chain_head)) &&
|
|
fcp->fw_number != IPFW_DEFAULT_RULE )
|
|
free_chain(fcp);
|
|
splx(s);
|
|
break;
|
|
|
|
case IP_FW_ADD:
|
|
error = sooptcopyin(sopt, &frwl, sizeof frwl, sizeof frwl);
|
|
if (error || (error = check_ipfw_struct(&frwl)))
|
|
break;
|
|
|
|
if (frwl.fw_number == IPFW_DEFAULT_RULE) {
|
|
dprintf(("%s can't add rule %u\n", err_prefix,
|
|
(unsigned)IPFW_DEFAULT_RULE));
|
|
error = EINVAL;
|
|
} else {
|
|
error = add_entry(&ip_fw_chain_head, &frwl);
|
|
if (!error && sopt->sopt_dir == SOPT_GET)
|
|
error = sooptcopyout(sopt, &frwl, sizeof frwl);
|
|
}
|
|
break;
|
|
|
|
case IP_FW_DEL:
|
|
error = sooptcopyin(sopt, &frwl, sizeof frwl, sizeof frwl);
|
|
if (error)
|
|
break;
|
|
|
|
if (frwl.fw_number == IPFW_DEFAULT_RULE) {
|
|
dprintf(("%s can't delete rule %u\n", err_prefix,
|
|
(unsigned)IPFW_DEFAULT_RULE));
|
|
error = EINVAL;
|
|
} else {
|
|
error = del_entry(&ip_fw_chain_head, frwl.fw_number);
|
|
}
|
|
break;
|
|
|
|
case IP_FW_ZERO:
|
|
case IP_FW_RESETLOG:
|
|
{
|
|
int cmd = (sopt->sopt_name == IP_FW_RESETLOG );
|
|
void *arg = NULL ;
|
|
|
|
if (sopt->sopt_val != 0) {
|
|
error = sooptcopyin(sopt, &frwl, sizeof frwl, sizeof frwl);
|
|
if (error)
|
|
break;
|
|
arg = &frwl ;
|
|
}
|
|
error = zero_entry(arg, cmd);
|
|
}
|
|
break;
|
|
|
|
default:
|
|
printf("ip_fw_ctl invalid option %d\n", sopt->sopt_name);
|
|
error = EINVAL ;
|
|
}
|
|
|
|
return (error);
|
|
}
|
|
|
|
/**
|
|
* dummynet needs a reference to the default rule, because rules can
|
|
* be deleted while packets hold a reference to them (e.g. to resume
|
|
* processing at the next rule). When this happens, dummynet changes
|
|
* the reference to the default rule (probably it could well be a
|
|
* NULL pointer, but this way we do not need to check for the special
|
|
* case, plus here he have info on the default behaviour.
|
|
*/
|
|
struct ip_fw *ip_fw_default_rule ;
|
|
|
|
void
|
|
ip_fw_init(void)
|
|
{
|
|
struct ip_fw default_rule;
|
|
|
|
ip_fw_chk_ptr = ip_fw_chk;
|
|
ip_fw_ctl_ptr = ip_fw_ctl;
|
|
LIST_INIT(&ip_fw_chain_head);
|
|
|
|
bzero(&default_rule, sizeof default_rule);
|
|
default_rule.fw_prot = IPPROTO_IP;
|
|
default_rule.fw_number = IPFW_DEFAULT_RULE;
|
|
#ifdef IPFIREWALL_DEFAULT_TO_ACCEPT
|
|
default_rule.fw_flg |= IP_FW_F_ACCEPT;
|
|
#else
|
|
default_rule.fw_flg |= IP_FW_F_DENY;
|
|
#endif
|
|
default_rule.fw_flg |= IP_FW_F_IN | IP_FW_F_OUT;
|
|
if (check_ipfw_struct(&default_rule) != 0 ||
|
|
add_entry(&ip_fw_chain_head, &default_rule))
|
|
panic("ip_fw_init");
|
|
|
|
ip_fw_default_rule = LIST_FIRST(&ip_fw_chain_head) ;
|
|
printf("IP packet filtering initialized, "
|
|
#ifdef IPDIVERT
|
|
"divert enabled, "
|
|
#else
|
|
"divert disabled, "
|
|
#endif
|
|
#ifdef IPFIREWALL_FORWARD
|
|
"rule-based forwarding enabled, "
|
|
#else
|
|
"rule-based forwarding disabled, "
|
|
#endif
|
|
#ifdef IPFIREWALL_DEFAULT_TO_ACCEPT
|
|
"default to accept, ");
|
|
#else
|
|
"default to deny, " );
|
|
#endif
|
|
#ifndef IPFIREWALL_VERBOSE
|
|
printf("logging disabled\n");
|
|
#else
|
|
if (fw_verbose_limit == 0)
|
|
printf("unlimited logging\n");
|
|
else
|
|
printf("logging limited to %d packets/entry by default\n",
|
|
fw_verbose_limit);
|
|
#endif
|
|
}
|
|
|
|
static int
|
|
ipfw_modevent(module_t mod, int type, void *unused)
|
|
{
|
|
int s;
|
|
int err = 0 ;
|
|
#if defined(KLD_MODULE)
|
|
struct ip_fw *fcp;
|
|
#endif
|
|
|
|
switch (type) {
|
|
case MOD_LOAD:
|
|
s = splimp();
|
|
if (IPFW_LOADED) {
|
|
splx(s);
|
|
printf("IP firewall already loaded\n");
|
|
err = EEXIST ;
|
|
} else {
|
|
ip_fw_init();
|
|
splx(s);
|
|
}
|
|
break ;
|
|
case MOD_UNLOAD:
|
|
#if !defined(KLD_MODULE)
|
|
printf("ipfw statically compiled, cannot unload\n");
|
|
err = EBUSY;
|
|
#else
|
|
s = splimp();
|
|
ip_fw_chk_ptr = NULL ;
|
|
ip_fw_ctl_ptr = NULL ;
|
|
while ( (fcp = LIST_FIRST(&ip_fw_chain_head)) != NULL)
|
|
free_chain(fcp);
|
|
splx(s);
|
|
printf("IP firewall unloaded\n");
|
|
#endif
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
return err;
|
|
}
|
|
|
|
static moduledata_t ipfwmod = {
|
|
"ipfw",
|
|
ipfw_modevent,
|
|
0
|
|
};
|
|
DECLARE_MODULE(ipfw, ipfwmod, SI_SUB_PSEUDO, SI_ORDER_ANY);
|
|
MODULE_VERSION(ipfw, 1);
|