File:  [DragonFly] / src / sys / net / ipfw / ip_fw2.c
Revision 1.10: download - view: text, annotated - select for diffs
Fri Mar 19 18:22:00 2004 UTC (10 years, 7 months ago) by hmp
Branches: MAIN
CVS tags: HEAD
Merge: FreeBSD (RELENG_4) ip_fw2.c rev. 1.6.2.19

	IN_MULTICAST wants an address in host byte order.

    1: /*
    2:  * Copyright (c) 2002 Luigi Rizzo, Universita` di Pisa
    3:  *
    4:  * Redistribution and use in source and binary forms, with or without
    5:  * modification, are permitted provided that the following conditions
    6:  * are met:
    7:  * 1. Redistributions of source code must retain the above copyright
    8:  *    notice, this list of conditions and the following disclaimer.
    9:  * 2. Redistributions in binary form must reproduce the above copyright
   10:  *    notice, this list of conditions and the following disclaimer in the
   11:  *    documentation and/or other materials provided with the distribution.
   12:  *
   13:  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   14:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   15:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   16:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   17:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   18:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   19:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   20:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   21:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   22:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   23:  * SUCH DAMAGE.
   24:  *
   25:  * $FreeBSD: src/sys/netinet/ip_fw2.c,v 1.6.2.12 2003/04/08 10:42:32 maxim Exp $
   26:  * $DragonFly: src/sys/net/ipfw/ip_fw2.c,v 1.10 2004/03/19 18:22:00 hmp Exp $
   27:  */
   28: 
   29: #define        DEB(x)
   30: #define        DDB(x) x
   31: 
   32: /*
   33:  * Implement IP packet firewall (new version)
   34:  */
   35: 
   36: #if !defined(KLD_MODULE)
   37: #include "opt_ipfw.h"
   38: #include "opt_ipdn.h"
   39: #include "opt_ipdivert.h"
   40: #include "opt_inet.h"
   41: #ifndef INET
   42: #error IPFIREWALL requires INET.
   43: #endif /* INET */
   44: #endif
   45: 
   46: #if IPFW2
   47: #include <sys/param.h>
   48: #include <sys/systm.h>
   49: #include <sys/malloc.h>
   50: #include <sys/mbuf.h>
   51: #include <sys/kernel.h>
   52: #include <sys/proc.h>
   53: #include <sys/socket.h>
   54: #include <sys/socketvar.h>
   55: #include <sys/sysctl.h>
   56: #include <sys/syslog.h>
   57: #include <sys/ucred.h>
   58: #include <sys/in_cksum.h>
   59: #include <net/if.h>
   60: #include <net/route.h>
   61: #include <netinet/in.h>
   62: #include <netinet/in_systm.h>
   63: #include <netinet/in_var.h>
   64: #include <netinet/in_pcb.h>
   65: #include <netinet/ip.h>
   66: #include <netinet/ip_var.h>
   67: #include <netinet/ip_icmp.h>
   68: #include "ip_fw.h"
   69: #include <net/dummynet/ip_dummynet.h>
   70: #include <netinet/tcp.h>
   71: #include <netinet/tcp_timer.h>
   72: #include <netinet/tcp_var.h>
   73: #include <netinet/tcpip.h>
   74: #include <netinet/udp.h>
   75: #include <netinet/udp_var.h>
   76: 
   77: #include <netinet/if_ether.h> /* XXX for ETHERTYPE_IP */
   78: 
   79: /*
   80:  * XXX This one should go in sys/mbuf.h. It is used to avoid that
   81:  * a firewall-generated packet loops forever through the firewall.
   82:  */
   83: #ifndef	M_SKIP_FIREWALL
   84: #define M_SKIP_FIREWALL         0x4000
   85: #endif
   86: 
   87: /*
   88:  * set_disable contains one bit per set value (0..31).
   89:  * If the bit is set, all rules with the corresponding set
   90:  * are disabled. Set 31 is reserved for the default rule
   91:  * and CANNOT be disabled.
   92:  */
   93: static u_int32_t set_disable;
   94: 
   95: static int fw_verbose;
   96: static int verbose_limit;
   97: 
   98: static struct callout_handle ipfw_timeout_h;
   99: #define	IPFW_DEFAULT_RULE	65535
  100: 
  101: /*
  102:  * list of rules for layer 3
  103:  */
  104: static struct ip_fw *layer3_chain;
  105: 
  106: MALLOC_DEFINE(M_IPFW, "IpFw/IpAcct", "IpFw/IpAcct chain's");
  107: 
  108: static int fw_debug = 1;
  109: static int autoinc_step = 100; /* bounded to 1..1000 in add_rule() */
  110: 
  111: #ifdef SYSCTL_NODE
  112: SYSCTL_NODE(_net_inet_ip, OID_AUTO, fw, CTLFLAG_RW, 0, "Firewall");
  113: SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, enable, CTLFLAG_RW,
  114:     &fw_enable, 0, "Enable ipfw");
  115: SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, autoinc_step, CTLFLAG_RW,
  116:     &autoinc_step, 0, "Rule number autincrement step");
  117: SYSCTL_INT(_net_inet_ip_fw, OID_AUTO,one_pass,CTLFLAG_RW,
  118:     &fw_one_pass, 0,
  119:     "Only do a single pass through ipfw when using dummynet(4)");
  120: SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, debug, CTLFLAG_RW,
  121:     &fw_debug, 0, "Enable printing of debug ip_fw statements");
  122: SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, verbose, CTLFLAG_RW,
  123:     &fw_verbose, 0, "Log matches to ipfw rules");
  124: SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, verbose_limit, CTLFLAG_RW,
  125:     &verbose_limit, 0, "Set upper limit of matches of ipfw rules logged");
  126: 
  127: /*
  128:  * Description of dynamic rules.
  129:  *
  130:  * Dynamic rules are stored in lists accessed through a hash table
  131:  * (ipfw_dyn_v) whose size is curr_dyn_buckets. This value can
  132:  * be modified through the sysctl variable dyn_buckets which is
  133:  * updated when the table becomes empty.
  134:  *
  135:  * XXX currently there is only one list, ipfw_dyn.
  136:  *
  137:  * When a packet is received, its address fields are first masked
  138:  * with the mask defined for the rule, then hashed, then matched
  139:  * against the entries in the corresponding list.
  140:  * Dynamic rules can be used for different purposes:
  141:  *  + stateful rules;
  142:  *  + enforcing limits on the number of sessions;
  143:  *  + in-kernel NAT (not implemented yet)
  144:  *
  145:  * The lifetime of dynamic rules is regulated by dyn_*_lifetime,
  146:  * measured in seconds and depending on the flags.
  147:  *
  148:  * The total number of dynamic rules is stored in dyn_count.
  149:  * The max number of dynamic rules is dyn_max. When we reach
  150:  * the maximum number of rules we do not create anymore. This is
  151:  * done to avoid consuming too much memory, but also too much
  152:  * time when searching on each packet (ideally, we should try instead
  153:  * to put a limit on the length of the list on each bucket...).
  154:  *
  155:  * Each dynamic rule holds a pointer to the parent ipfw rule so
  156:  * we know what action to perform. Dynamic rules are removed when
  157:  * the parent rule is deleted. XXX we should make them survive.
  158:  *
  159:  * There are some limitations with dynamic rules -- we do not
  160:  * obey the 'randomized match', and we do not do multiple
  161:  * passes through the firewall. XXX check the latter!!!
  162:  */
  163: static ipfw_dyn_rule **ipfw_dyn_v = NULL;
  164: static u_int32_t dyn_buckets = 256; /* must be power of 2 */
  165: static u_int32_t curr_dyn_buckets = 256; /* must be power of 2 */
  166: 
  167: /*
  168:  * Timeouts for various events in handing dynamic rules.
  169:  */
  170: static u_int32_t dyn_ack_lifetime = 300;
  171: static u_int32_t dyn_syn_lifetime = 20;
  172: static u_int32_t dyn_fin_lifetime = 1;
  173: static u_int32_t dyn_rst_lifetime = 1;
  174: static u_int32_t dyn_udp_lifetime = 10;
  175: static u_int32_t dyn_short_lifetime = 5;
  176: 
  177: /*
  178:  * Keepalives are sent if dyn_keepalive is set. They are sent every
  179:  * dyn_keepalive_period seconds, in the last dyn_keepalive_interval
  180:  * seconds of lifetime of a rule.
  181:  * dyn_rst_lifetime and dyn_fin_lifetime should be strictly lower
  182:  * than dyn_keepalive_period.
  183:  */
  184: 
  185: static u_int32_t dyn_keepalive_interval = 20;
  186: static u_int32_t dyn_keepalive_period = 5;
  187: static u_int32_t dyn_keepalive = 1;	/* do send keepalives */
  188: 
  189: static u_int32_t static_count;	/* # of static rules */
  190: static u_int32_t static_len;	/* size in bytes of static rules */
  191: static u_int32_t dyn_count;		/* # of dynamic rules */
  192: static u_int32_t dyn_max = 4096;	/* max # of dynamic rules */
  193: 
  194: SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_buckets, CTLFLAG_RW,
  195:     &dyn_buckets, 0, "Number of dyn. buckets");
  196: SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, curr_dyn_buckets, CTLFLAG_RD,
  197:     &curr_dyn_buckets, 0, "Current Number of dyn. buckets");
  198: SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_count, CTLFLAG_RD,
  199:     &dyn_count, 0, "Number of dyn. rules");
  200: SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_max, CTLFLAG_RW,
  201:     &dyn_max, 0, "Max number of dyn. rules");
  202: SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, static_count, CTLFLAG_RD,
  203:     &static_count, 0, "Number of static rules");
  204: SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_ack_lifetime, CTLFLAG_RW,
  205:     &dyn_ack_lifetime, 0, "Lifetime of dyn. rules for acks");
  206: SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_syn_lifetime, CTLFLAG_RW,
  207:     &dyn_syn_lifetime, 0, "Lifetime of dyn. rules for syn");
  208: SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_fin_lifetime, CTLFLAG_RW,
  209:     &dyn_fin_lifetime, 0, "Lifetime of dyn. rules for fin");
  210: SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_rst_lifetime, CTLFLAG_RW,
  211:     &dyn_rst_lifetime, 0, "Lifetime of dyn. rules for rst");
  212: SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_udp_lifetime, CTLFLAG_RW,
  213:     &dyn_udp_lifetime, 0, "Lifetime of dyn. rules for UDP");
  214: SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_short_lifetime, CTLFLAG_RW,
  215:     &dyn_short_lifetime, 0, "Lifetime of dyn. rules for other situations");
  216: SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, dyn_keepalive, CTLFLAG_RW,
  217:     &dyn_keepalive, 0, "Enable keepalives for dyn. rules");
  218: 
  219: #endif /* SYSCTL_NODE */
  220: 
  221: 
  222: static ip_fw_chk_t	ipfw_chk;
  223: 
  224: ip_dn_ruledel_t *ip_dn_ruledel_ptr = NULL;	/* hook into dummynet */
  225: 
  226: /*
  227:  * This macro maps an ip pointer into a layer3 header pointer of type T
  228:  */
  229: #define	L3HDR(T, ip) ((T *)((u_int32_t *)(ip) + (ip)->ip_hl))
  230: 
  231: static __inline int
  232: icmptype_match(struct ip *ip, ipfw_insn_u32 *cmd)
  233: {
  234: 	int type = L3HDR(struct icmp,ip)->icmp_type;
  235: 
  236: 	return (type <= ICMP_MAXTYPE && (cmd->d[0] & (1<<type)) );
  237: }
  238: 
  239: #define TT	( (1 << ICMP_ECHO) | (1 << ICMP_ROUTERSOLICIT) | \
  240:     (1 << ICMP_TSTAMP) | (1 << ICMP_IREQ) | (1 << ICMP_MASKREQ) )
  241: 
  242: static int
  243: is_icmp_query(struct ip *ip)
  244: {
  245: 	int type = L3HDR(struct icmp, ip)->icmp_type;
  246: 	return (type <= ICMP_MAXTYPE && (TT & (1<<type)) );
  247: }
  248: #undef TT
  249: 
  250: /*
  251:  * The following checks use two arrays of 8 or 16 bits to store the
  252:  * bits that we want set or clear, respectively. They are in the
  253:  * low and high half of cmd->arg1 or cmd->d[0].
  254:  *
  255:  * We scan options and store the bits we find set. We succeed if
  256:  *
  257:  *	(want_set & ~bits) == 0 && (want_clear & ~bits) == want_clear
  258:  *
  259:  * The code is sometimes optimized not to store additional variables.
  260:  */
  261: 
  262: static int
  263: flags_match(ipfw_insn *cmd, u_int8_t bits)
  264: {
  265: 	u_char want_clear;
  266: 	bits = ~bits;
  267: 
  268: 	if ( ((cmd->arg1 & 0xff) & bits) != 0)
  269: 		return 0; /* some bits we want set were clear */
  270: 	want_clear = (cmd->arg1 >> 8) & 0xff;
  271: 	if ( (want_clear & bits) != want_clear)
  272: 		return 0; /* some bits we want clear were set */
  273: 	return 1;
  274: }
  275: 
  276: static int
  277: ipopts_match(struct ip *ip, ipfw_insn *cmd)
  278: {
  279: 	int optlen, bits = 0;
  280: 	u_char *cp = (u_char *)(ip + 1);
  281: 	int x = (ip->ip_hl << 2) - sizeof (struct ip);
  282: 
  283: 	for (; x > 0; x -= optlen, cp += optlen) {
  284: 		int opt = cp[IPOPT_OPTVAL];
  285: 
  286: 		if (opt == IPOPT_EOL)
  287: 			break;
  288: 		if (opt == IPOPT_NOP)
  289: 			optlen = 1;
  290: 		else {
  291: 			optlen = cp[IPOPT_OLEN];
  292: 			if (optlen <= 0 || optlen > x)
  293: 				return 0; /* invalid or truncated */
  294: 		}
  295: 		switch (opt) {
  296: 
  297: 		default:
  298: 			break;
  299: 
  300: 		case IPOPT_LSRR:
  301: 			bits |= IP_FW_IPOPT_LSRR;
  302: 			break;
  303: 
  304: 		case IPOPT_SSRR:
  305: 			bits |= IP_FW_IPOPT_SSRR;
  306: 			break;
  307: 
  308: 		case IPOPT_RR:
  309: 			bits |= IP_FW_IPOPT_RR;
  310: 			break;
  311: 
  312: 		case IPOPT_TS:
  313: 			bits |= IP_FW_IPOPT_TS;
  314: 			break;
  315: 		}
  316: 	}
  317: 	return (flags_match(cmd, bits));
  318: }
  319: 
  320: static int
  321: tcpopts_match(struct ip *ip, ipfw_insn *cmd)
  322: {
  323: 	int optlen, bits = 0;
  324: 	struct tcphdr *tcp = L3HDR(struct tcphdr,ip);
  325: 	u_char *cp = (u_char *)(tcp + 1);
  326: 	int x = (tcp->th_off << 2) - sizeof(struct tcphdr);
  327: 
  328: 	for (; x > 0; x -= optlen, cp += optlen) {
  329: 		int opt = cp[0];
  330: 		if (opt == TCPOPT_EOL)
  331: 			break;
  332: 		if (opt == TCPOPT_NOP)
  333: 			optlen = 1;
  334: 		else {
  335: 			optlen = cp[1];
  336: 			if (optlen <= 0)
  337: 				break;
  338: 		}
  339: 
  340: 		switch (opt) {
  341: 
  342: 		default:
  343: 			break;
  344: 
  345: 		case TCPOPT_MAXSEG:
  346: 			bits |= IP_FW_TCPOPT_MSS;
  347: 			break;
  348: 
  349: 		case TCPOPT_WINDOW:
  350: 			bits |= IP_FW_TCPOPT_WINDOW;
  351: 			break;
  352: 
  353: 		case TCPOPT_SACK_PERMITTED:
  354: 		case TCPOPT_SACK:
  355: 			bits |= IP_FW_TCPOPT_SACK;
  356: 			break;
  357: 
  358: 		case TCPOPT_TIMESTAMP:
  359: 			bits |= IP_FW_TCPOPT_TS;
  360: 			break;
  361: 
  362: 		case TCPOPT_CC:
  363: 		case TCPOPT_CCNEW:
  364: 		case TCPOPT_CCECHO:
  365: 			bits |= IP_FW_TCPOPT_CC;
  366: 			break;
  367: 		}
  368: 	}
  369: 	return (flags_match(cmd, bits));
  370: }
  371: 
  372: static int
  373: iface_match(struct ifnet *ifp, ipfw_insn_if *cmd)
  374: {
  375: 	if (ifp == NULL)	/* no iface with this packet, match fails */
  376: 		return 0;
  377: 	/* Check by name or by IP address */
  378: 	if (cmd->name[0] != '\0') { /* match by name */
  379: 		/* Check name */
  380: 		if (cmd->p.glob) {
  381: 			if (fnmatch(cmd->name, ifp->if_xname, 0) == 0)
  382: 				return(1);
  383: 		} else {
  384: 			if (strncmp(ifp->if_xname, cmd->name, IFNAMSIZ) == 0)
  385: 				return(1);
  386: 		}
  387: 	} else {
  388: 		struct ifaddr *ia;
  389: 
  390: 		TAILQ_FOREACH(ia, &ifp->if_addrhead, ifa_link) {
  391: 			if (ia->ifa_addr == NULL)
  392: 				continue;
  393: 			if (ia->ifa_addr->sa_family != AF_INET)
  394: 				continue;
  395: 			if (cmd->p.ip.s_addr == ((struct sockaddr_in *)
  396: 			    (ia->ifa_addr))->sin_addr.s_addr)
  397: 				return(1);	/* match */
  398: 		}
  399: 	}
  400: 	return(0);	/* no match, fail ... */
  401: }
  402: 
  403: static u_int64_t norule_counter;	/* counter for ipfw_log(NULL...) */
  404: 
  405: #define SNPARGS(buf, len) buf + len, sizeof(buf) > len ? sizeof(buf) - len : 0
  406: #define SNP(buf) buf, sizeof(buf)
  407: 
  408: /*
  409:  * We enter here when we have a rule with O_LOG.
  410:  * XXX this function alone takes about 2Kbytes of code!
  411:  */
  412: static void
  413: ipfw_log(struct ip_fw *f, u_int hlen, struct ether_header *eh,
  414: 	struct mbuf *m, struct ifnet *oif)
  415: {
  416: 	char *action;
  417: 	int limit_reached = 0;
  418: 	char action2[40], proto[48], fragment[28];
  419: 
  420: 	fragment[0] = '\0';
  421: 	proto[0] = '\0';
  422: 
  423: 	if (f == NULL) {	/* bogus pkt */
  424: 		if (verbose_limit != 0 && norule_counter >= verbose_limit)
  425: 			return;
  426: 		norule_counter++;
  427: 		if (norule_counter == verbose_limit)
  428: 			limit_reached = verbose_limit;
  429: 		action = "Refuse";
  430: 	} else {	/* O_LOG is the first action, find the real one */
  431: 		ipfw_insn *cmd = ACTION_PTR(f);
  432: 		ipfw_insn_log *l = (ipfw_insn_log *)cmd;
  433: 
  434: 		if (l->max_log != 0 && l->log_left == 0)
  435: 			return;
  436: 		l->log_left--;
  437: 		if (l->log_left == 0)
  438: 			limit_reached = l->max_log;
  439: 		cmd += F_LEN(cmd);	/* point to first action */
  440: 		if (cmd->opcode == O_PROB)
  441: 			cmd += F_LEN(cmd);
  442: 
  443: 		action = action2;
  444: 		switch (cmd->opcode) {
  445: 		case O_DENY:
  446: 			action = "Deny";
  447: 			break;
  448: 
  449: 		case O_REJECT:
  450: 			if (cmd->arg1==ICMP_REJECT_RST)
  451: 				action = "Reset";
  452: 			else if (cmd->arg1==ICMP_UNREACH_HOST)
  453: 				action = "Reject";
  454: 			else
  455: 				snprintf(SNPARGS(action2, 0), "Unreach %d",
  456: 					cmd->arg1);
  457: 			break;
  458: 
  459: 		case O_ACCEPT:
  460: 			action = "Accept";
  461: 			break;
  462: 		case O_COUNT:
  463: 			action = "Count";
  464: 			break;
  465: 		case O_DIVERT:
  466: 			snprintf(SNPARGS(action2, 0), "Divert %d",
  467: 				cmd->arg1);
  468: 			break;
  469: 		case O_TEE:
  470: 			snprintf(SNPARGS(action2, 0), "Tee %d",
  471: 				cmd->arg1);
  472: 			break;
  473: 		case O_SKIPTO:
  474: 			snprintf(SNPARGS(action2, 0), "SkipTo %d",
  475: 				cmd->arg1);
  476: 			break;
  477: 		case O_PIPE:
  478: 			snprintf(SNPARGS(action2, 0), "Pipe %d",
  479: 				cmd->arg1);
  480: 			break;
  481: 		case O_QUEUE:
  482: 			snprintf(SNPARGS(action2, 0), "Queue %d",
  483: 				cmd->arg1);
  484: 			break;
  485: 		case O_FORWARD_IP: {
  486: 			ipfw_insn_sa *sa = (ipfw_insn_sa *)cmd;
  487: 			int len;
  488: 
  489: 			len = snprintf(SNPARGS(action2, 0), "Forward to %s",
  490: 				inet_ntoa(sa->sa.sin_addr));
  491: 			if (sa->sa.sin_port)
  492: 				snprintf(SNPARGS(action2, len), ":%d",
  493: 				    sa->sa.sin_port);
  494: 			}
  495: 			break;
  496: 		default:
  497: 			action = "UNKNOWN";
  498: 			break;
  499: 		}
  500: 	}
  501: 
  502: 	if (hlen == 0) {	/* non-ip */
  503: 		snprintf(SNPARGS(proto, 0), "MAC");
  504: 	} else {
  505: 		struct ip *ip = mtod(m, struct ip *);
  506: 		/* these three are all aliases to the same thing */
  507: 		struct icmp *const icmp = L3HDR(struct icmp, ip);
  508: 		struct tcphdr *const tcp = (struct tcphdr *)icmp;
  509: 		struct udphdr *const udp = (struct udphdr *)icmp;
  510: 
  511: 		int ip_off, offset, ip_len;
  512: 
  513: 		int len;
  514: 
  515: 		if (eh != NULL) { /* layer 2 packets are as on the wire */
  516: 			ip_off = ntohs(ip->ip_off);
  517: 			ip_len = ntohs(ip->ip_len);
  518: 		} else {
  519: 			ip_off = ip->ip_off;
  520: 			ip_len = ip->ip_len;
  521: 		}
  522: 		offset = ip_off & IP_OFFMASK;
  523: 		switch (ip->ip_p) {
  524: 		case IPPROTO_TCP:
  525: 			len = snprintf(SNPARGS(proto, 0), "TCP %s",
  526: 			    inet_ntoa(ip->ip_src));
  527: 			if (offset == 0)
  528: 				snprintf(SNPARGS(proto, len), ":%d %s:%d",
  529: 				    ntohs(tcp->th_sport),
  530: 				    inet_ntoa(ip->ip_dst),
  531: 				    ntohs(tcp->th_dport));
  532: 			else
  533: 				snprintf(SNPARGS(proto, len), " %s",
  534: 				    inet_ntoa(ip->ip_dst));
  535: 			break;
  536: 
  537: 		case IPPROTO_UDP:
  538: 			len = snprintf(SNPARGS(proto, 0), "UDP %s",
  539: 				inet_ntoa(ip->ip_src));
  540: 			if (offset == 0)
  541: 				snprintf(SNPARGS(proto, len), ":%d %s:%d",
  542: 				    ntohs(udp->uh_sport),
  543: 				    inet_ntoa(ip->ip_dst),
  544: 				    ntohs(udp->uh_dport));
  545: 			else
  546: 				snprintf(SNPARGS(proto, len), " %s",
  547: 				    inet_ntoa(ip->ip_dst));
  548: 			break;
  549: 
  550: 		case IPPROTO_ICMP:
  551: 			if (offset == 0)
  552: 				len = snprintf(SNPARGS(proto, 0),
  553: 				    "ICMP:%u.%u ",
  554: 				    icmp->icmp_type, icmp->icmp_code);
  555: 			else
  556: 				len = snprintf(SNPARGS(proto, 0), "ICMP ");
  557: 			len += snprintf(SNPARGS(proto, len), "%s",
  558: 			    inet_ntoa(ip->ip_src));
  559: 			snprintf(SNPARGS(proto, len), " %s",
  560: 			    inet_ntoa(ip->ip_dst));
  561: 			break;
  562: 
  563: 		default:
  564: 			len = snprintf(SNPARGS(proto, 0), "P:%d %s", ip->ip_p,
  565: 			    inet_ntoa(ip->ip_src));
  566: 			snprintf(SNPARGS(proto, len), " %s",
  567: 			    inet_ntoa(ip->ip_dst));
  568: 			break;
  569: 		}
  570: 
  571: 		if (ip_off & (IP_MF | IP_OFFMASK))
  572: 			snprintf(SNPARGS(fragment, 0), " (frag %d:%d@%d%s)",
  573: 			     ntohs(ip->ip_id), ip_len - (ip->ip_hl << 2),
  574: 			     offset << 3,
  575: 			     (ip_off & IP_MF) ? "+" : "");
  576: 	}
  577: 	if (oif || m->m_pkthdr.rcvif)
  578: 		log(LOG_SECURITY | LOG_INFO,
  579: 		    "ipfw: %d %s %s %s via %s%s\n",
  580: 		    f ? f->rulenum : -1,
  581: 		    action, proto, oif ? "out" : "in",
  582: 		    oif ? oif->if_xname : m->m_pkthdr.rcvif->if_xname,
  583: 		    fragment);
  584: 	else
  585: 		log(LOG_SECURITY | LOG_INFO,
  586: 		    "ipfw: %d %s %s [no if info]%s\n",
  587: 		    f ? f->rulenum : -1,
  588: 		    action, proto, fragment);
  589: 	if (limit_reached)
  590: 		log(LOG_SECURITY | LOG_NOTICE,
  591: 		    "ipfw: limit %d reached on entry %d\n",
  592: 		    limit_reached, f ? f->rulenum : -1);
  593: }
  594: 
  595: /*
  596:  * IMPORTANT: the hash function for dynamic rules must be commutative
  597:  * in source and destination (ip,port), because rules are bidirectional
  598:  * and we want to find both in the same bucket.
  599:  */
  600: static __inline int
  601: hash_packet(struct ipfw_flow_id *id)
  602: {
  603: 	u_int32_t i;
  604: 
  605: 	i = (id->dst_ip) ^ (id->src_ip) ^ (id->dst_port) ^ (id->src_port);
  606: 	i &= (curr_dyn_buckets - 1);
  607: 	return i;
  608: }
  609: 
  610: /**
  611:  * unlink a dynamic rule from a chain. prev is a pointer to
  612:  * the previous one, q is a pointer to the rule to delete,
  613:  * head is a pointer to the head of the queue.
  614:  * Modifies q and potentially also head.
  615:  */
  616: #define UNLINK_DYN_RULE(prev, head, q) {				\
  617: 	ipfw_dyn_rule *old_q = q;					\
  618: 									\
  619: 	/* remove a refcount to the parent */				\
  620: 	if (q->dyn_type == O_LIMIT)					\
  621: 		q->parent->count--;					\
  622: 	DEB(printf("-- unlink entry 0x%08x %d -> 0x%08x %d, %d left\n",	\
  623: 		(q->id.src_ip), (q->id.src_port),			\
  624: 		(q->id.dst_ip), (q->id.dst_port), dyn_count-1 ); )	\
  625: 	if (prev != NULL)						\
  626: 		prev->next = q = q->next;				\
  627: 	else								\
  628: 		head = q = q->next;					\
  629: 	dyn_count--;							\
  630: 	free(old_q, M_IPFW); }
  631: 
  632: #define TIME_LEQ(a,b)       ((int)((a)-(b)) <= 0)
  633: 
  634: /**
  635:  * Remove dynamic rules pointing to "rule", or all of them if rule == NULL.
  636:  *
  637:  * If keep_me == NULL, rules are deleted even if not expired,
  638:  * otherwise only expired rules are removed.
  639:  *
  640:  * The value of the second parameter is also used to point to identify
  641:  * a rule we absolutely do not want to remove (e.g. because we are
  642:  * holding a reference to it -- this is the case with O_LIMIT_PARENT
  643:  * rules). The pointer is only used for comparison, so any non-null
  644:  * value will do.
  645:  */
  646: static void
  647: remove_dyn_rule(struct ip_fw *rule, ipfw_dyn_rule *keep_me)
  648: {
  649: 	static u_int32_t last_remove = 0;
  650: 
  651: #define FORCE (keep_me == NULL)
  652: 
  653: 	ipfw_dyn_rule *prev, *q;
  654: 	int i, pass = 0, max_pass = 0;
  655: 
  656: 	if (ipfw_dyn_v == NULL || dyn_count == 0)
  657: 		return;
  658: 	/* do not expire more than once per second, it is useless */
  659: 	if (!FORCE && last_remove == time_second)
  660: 		return;
  661: 	last_remove = time_second;
  662: 
  663: 	/*
  664: 	 * because O_LIMIT refer to parent rules, during the first pass only
  665: 	 * remove child and mark any pending LIMIT_PARENT, and remove
  666: 	 * them in a second pass.
  667: 	 */
  668: next_pass:
  669: 	for (i = 0 ; i < curr_dyn_buckets ; i++) {
  670: 		for (prev=NULL, q = ipfw_dyn_v[i] ; q ; ) {
  671: 			/*
  672: 			 * Logic can become complex here, so we split tests.
  673: 			 */
  674: 			if (q == keep_me)
  675: 				goto next;
  676: 			if (rule != NULL && rule != q->rule)
  677: 				goto next; /* not the one we are looking for */
  678: 			if (q->dyn_type == O_LIMIT_PARENT) {
  679: 				/*
  680: 				 * handle parent in the second pass,
  681: 				 * record we need one.
  682: 				 */
  683: 				max_pass = 1;
  684: 				if (pass == 0)
  685: 					goto next;
  686: 				if (FORCE && q->count != 0 ) {
  687: 					/* XXX should not happen! */
  688: 					printf( "OUCH! cannot remove rule,"
  689: 					     " count %d\n", q->count);
  690: 				}
  691: 			} else {
  692: 				if (!FORCE &&
  693: 				    !TIME_LEQ( q->expire, time_second ))
  694: 					goto next;
  695: 			}
  696: 			UNLINK_DYN_RULE(prev, ipfw_dyn_v[i], q);
  697: 			continue;
  698: next:
  699: 			prev=q;
  700: 			q=q->next;
  701: 		}
  702: 	}
  703: 	if (pass++ < max_pass)
  704: 		goto next_pass;
  705: }
  706: 
  707: 
  708: /**
  709:  * lookup a dynamic rule.
  710:  */
  711: static ipfw_dyn_rule *
  712: lookup_dyn_rule(struct ipfw_flow_id *pkt, int *match_direction,
  713: 	struct tcphdr *tcp)
  714: {
  715: 	/*
  716: 	 * stateful ipfw extensions.
  717: 	 * Lookup into dynamic session queue
  718: 	 */
  719: #define MATCH_REVERSE	0
  720: #define MATCH_FORWARD	1
  721: #define MATCH_NONE	2
  722: #define MATCH_UNKNOWN	3
  723: 	int i, dir = MATCH_NONE;
  724: 	ipfw_dyn_rule *prev, *q=NULL;
  725: 
  726: 	if (ipfw_dyn_v == NULL)
  727: 		goto done;	/* not found */
  728: 	i = hash_packet( pkt );
  729: 	for (prev=NULL, q = ipfw_dyn_v[i] ; q != NULL ; ) {
  730: 		if (q->dyn_type == O_LIMIT_PARENT)
  731: 			goto next;
  732: 		if (TIME_LEQ( q->expire, time_second)) { /* expire entry */
  733: 			UNLINK_DYN_RULE(prev, ipfw_dyn_v[i], q);
  734: 			continue;
  735: 		}
  736: 		if ( pkt->proto == q->id.proto) {
  737: 			if (pkt->src_ip == q->id.src_ip &&
  738: 			    pkt->dst_ip == q->id.dst_ip &&
  739: 			    pkt->src_port == q->id.src_port &&
  740: 			    pkt->dst_port == q->id.dst_port ) {
  741: 				dir = MATCH_FORWARD;
  742: 				break;
  743: 			}
  744: 			if (pkt->src_ip == q->id.dst_ip &&
  745: 			    pkt->dst_ip == q->id.src_ip &&
  746: 			    pkt->src_port == q->id.dst_port &&
  747: 			    pkt->dst_port == q->id.src_port ) {
  748: 				dir = MATCH_REVERSE;
  749: 				break;
  750: 			}
  751: 		}
  752: next:
  753: 		prev = q;
  754: 		q = q->next;
  755: 	}
  756: 	if (q == NULL)
  757: 		goto done; /* q = NULL, not found */
  758: 
  759: 	if ( prev != NULL) { /* found and not in front */
  760: 		prev->next = q->next;
  761: 		q->next = ipfw_dyn_v[i];
  762: 		ipfw_dyn_v[i] = q;
  763: 	}
  764: 	if (pkt->proto == IPPROTO_TCP) { /* update state according to flags */
  765: 		u_char flags = pkt->flags & (TH_FIN|TH_SYN|TH_RST);
  766: 
  767: #define BOTH_SYN	(TH_SYN | (TH_SYN << 8))
  768: #define BOTH_FIN	(TH_FIN | (TH_FIN << 8))
  769: 		q->state |= (dir == MATCH_FORWARD ) ? flags : (flags << 8);
  770: 		switch (q->state) {
  771: 		case TH_SYN:				/* opening */
  772: 			q->expire = time_second + dyn_syn_lifetime;
  773: 			break;
  774: 
  775: 		case BOTH_SYN:			/* move to established */
  776: 		case BOTH_SYN | TH_FIN :	/* one side tries to close */
  777: 		case BOTH_SYN | (TH_FIN << 8) :
  778:  			if (tcp) {
  779: #define _SEQ_GE(a,b) ((int)(a) - (int)(b) >= 0)
  780: 			    u_int32_t ack = ntohl(tcp->th_ack);
  781: 			    if (dir == MATCH_FORWARD) {
  782: 				if (q->ack_fwd == 0 || _SEQ_GE(ack, q->ack_fwd))
  783: 				    q->ack_fwd = ack;
  784: 				else { /* ignore out-of-sequence */
  785: 				    break;
  786: 				}
  787: 			    } else {
  788: 				if (q->ack_rev == 0 || _SEQ_GE(ack, q->ack_rev))
  789: 				    q->ack_rev = ack;
  790: 				else { /* ignore out-of-sequence */
  791: 				    break;
  792: 				}
  793: 			    }
  794: 			}
  795: 			q->expire = time_second + dyn_ack_lifetime;
  796: 			break;
  797: 
  798: 		case BOTH_SYN | BOTH_FIN:	/* both sides closed */
  799: 			if (dyn_fin_lifetime >= dyn_keepalive_period)
  800: 				dyn_fin_lifetime = dyn_keepalive_period - 1;
  801: 			q->expire = time_second + dyn_fin_lifetime;
  802: 			break;
  803: 
  804: 		default:
  805: #if 0
  806: 			/*
  807: 			 * reset or some invalid combination, but can also
  808: 			 * occur if we use keep-state the wrong way.
  809: 			 */
  810: 			if ( (q->state & ((TH_RST << 8)|TH_RST)) == 0)
  811: 				printf("invalid state: 0x%x\n", q->state);
  812: #endif
  813: 			if (dyn_rst_lifetime >= dyn_keepalive_period)
  814: 				dyn_rst_lifetime = dyn_keepalive_period - 1;
  815: 			q->expire = time_second + dyn_rst_lifetime;
  816: 			break;
  817: 		}
  818: 	} else if (pkt->proto == IPPROTO_UDP) {
  819: 		q->expire = time_second + dyn_udp_lifetime;
  820: 	} else {
  821: 		/* other protocols */
  822: 		q->expire = time_second + dyn_short_lifetime;
  823: 	}
  824: done:
  825: 	if (match_direction)
  826: 		*match_direction = dir;
  827: 	return q;
  828: }
  829: 
  830: static void
  831: realloc_dynamic_table(void)
  832: {
  833: 	/*
  834: 	 * Try reallocation, make sure we have a power of 2 and do
  835: 	 * not allow more than 64k entries. In case of overflow,
  836: 	 * default to 1024.
  837: 	 */
  838: 
  839: 	if (dyn_buckets > 65536)
  840: 		dyn_buckets = 1024;
  841: 	if ((dyn_buckets & (dyn_buckets-1)) != 0) { /* not a power of 2 */
  842: 		dyn_buckets = curr_dyn_buckets; /* reset */
  843: 		return;
  844: 	}
  845: 	curr_dyn_buckets = dyn_buckets;
  846: 	if (ipfw_dyn_v != NULL)
  847: 		free(ipfw_dyn_v, M_IPFW);
  848: 	for (;;) {
  849: 		ipfw_dyn_v = malloc(curr_dyn_buckets * sizeof(ipfw_dyn_rule *),
  850: 		       M_IPFW, M_WAITOK | M_ZERO);
  851: 		if (ipfw_dyn_v != NULL || curr_dyn_buckets <= 2)
  852: 			break;
  853: 		curr_dyn_buckets /= 2;
  854: 	}
  855: }
  856: 
  857: /**
  858:  * Install state of type 'type' for a dynamic session.
  859:  * The hash table contains two type of rules:
  860:  * - regular rules (O_KEEP_STATE)
  861:  * - rules for sessions with limited number of sess per user
  862:  *   (O_LIMIT). When they are created, the parent is
  863:  *   increased by 1, and decreased on delete. In this case,
  864:  *   the third parameter is the parent rule and not the chain.
  865:  * - "parent" rules for the above (O_LIMIT_PARENT).
  866:  */
  867: static ipfw_dyn_rule *
  868: add_dyn_rule(struct ipfw_flow_id *id, u_int8_t dyn_type, struct ip_fw *rule)
  869: {
  870: 	ipfw_dyn_rule *r;
  871: 	int i;
  872: 
  873: 	if (ipfw_dyn_v == NULL ||
  874: 	    (dyn_count == 0 && dyn_buckets != curr_dyn_buckets)) {
  875: 		realloc_dynamic_table();
  876: 		if (ipfw_dyn_v == NULL)
  877: 			return NULL; /* failed ! */
  878: 	}
  879: 	i = hash_packet(id);
  880: 
  881: 	r = malloc(sizeof *r, M_IPFW, M_WAITOK | M_ZERO);
  882: 	if (r == NULL) {
  883: 		printf ("sorry cannot allocate state\n");
  884: 		return NULL;
  885: 	}
  886: 
  887: 	/* increase refcount on parent, and set pointer */
  888: 	if (dyn_type == O_LIMIT) {
  889: 		ipfw_dyn_rule *parent = (ipfw_dyn_rule *)rule;
  890: 		if ( parent->dyn_type != O_LIMIT_PARENT)
  891: 			panic("invalid parent");
  892: 		parent->count++;
  893: 		r->parent = parent;
  894: 		rule = parent->rule;
  895: 	}
  896: 
  897: 	r->id = *id;
  898: 	r->expire = time_second + dyn_syn_lifetime;
  899: 	r->rule = rule;
  900: 	r->dyn_type = dyn_type;
  901: 	r->pcnt = r->bcnt = 0;
  902: 	r->count = 0;
  903: 
  904: 	r->bucket = i;
  905: 	r->next = ipfw_dyn_v[i];
  906: 	ipfw_dyn_v[i] = r;
  907: 	dyn_count++;
  908: 	DEB(printf("-- add dyn entry ty %d 0x%08x %d -> 0x%08x %d, total %d\n",
  909: 	   dyn_type,
  910: 	   (r->id.src_ip), (r->id.src_port),
  911: 	   (r->id.dst_ip), (r->id.dst_port),
  912: 	   dyn_count ); )
  913: 	return r;
  914: }
  915: 
  916: /**
  917:  * lookup dynamic parent rule using pkt and rule as search keys.
  918:  * If the lookup fails, then install one.
  919:  */
  920: static ipfw_dyn_rule *
  921: lookup_dyn_parent(struct ipfw_flow_id *pkt, struct ip_fw *rule)
  922: {
  923: 	ipfw_dyn_rule *q;
  924: 	int i;
  925: 
  926: 	if (ipfw_dyn_v) {
  927: 		i = hash_packet( pkt );
  928: 		for (q = ipfw_dyn_v[i] ; q != NULL ; q=q->next)
  929: 			if (q->dyn_type == O_LIMIT_PARENT &&
  930: 			    rule== q->rule &&
  931: 			    pkt->proto == q->id.proto &&
  932: 			    pkt->src_ip == q->id.src_ip &&
  933: 			    pkt->dst_ip == q->id.dst_ip &&
  934: 			    pkt->src_port == q->id.src_port &&
  935: 			    pkt->dst_port == q->id.dst_port) {
  936: 				q->expire = time_second + dyn_short_lifetime;
  937: 				DEB(printf("lookup_dyn_parent found 0x%p\n",q);)
  938: 				return q;
  939: 			}
  940: 	}
  941: 	return add_dyn_rule(pkt, O_LIMIT_PARENT, rule);
  942: }
  943: 
  944: /**
  945:  * Install dynamic state for rule type cmd->o.opcode
  946:  *
  947:  * Returns 1 (failure) if state is not installed because of errors or because
  948:  * session limitations are enforced.
  949:  */
  950: static int
  951: install_state(struct ip_fw *rule, ipfw_insn_limit *cmd,
  952: 	struct ip_fw_args *args)
  953: {
  954: 	static int last_log;
  955: 
  956: 	ipfw_dyn_rule *q;
  957: 
  958: 	DEB(printf("-- install state type %d 0x%08x %u -> 0x%08x %u\n",
  959: 	    cmd->o.opcode,
  960: 	    (args->f_id.src_ip), (args->f_id.src_port),
  961: 	    (args->f_id.dst_ip), (args->f_id.dst_port) );)
  962: 
  963: 	q = lookup_dyn_rule(&args->f_id, NULL, NULL);
  964: 
  965: 	if (q != NULL) { /* should never occur */
  966: 		if (last_log != time_second) {
  967: 			last_log = time_second;
  968: 			printf(" install_state: entry already present, done\n");
  969: 		}
  970: 		return 0;
  971: 	}
  972: 
  973: 	if (dyn_count >= dyn_max)
  974: 		/*
  975: 		 * Run out of slots, try to remove any expired rule.
  976: 		 */
  977: 		remove_dyn_rule(NULL, (ipfw_dyn_rule *)1);
  978: 
  979: 	if (dyn_count >= dyn_max) {
  980: 		if (last_log != time_second) {
  981: 			last_log = time_second;
  982: 			printf("install_state: Too many dynamic rules\n");
  983: 		}
  984: 		return 1; /* cannot install, notify caller */
  985: 	}
  986: 
  987: 	switch (cmd->o.opcode) {
  988: 	case O_KEEP_STATE: /* bidir rule */
  989: 		add_dyn_rule(&args->f_id, O_KEEP_STATE, rule);
  990: 		break;
  991: 
  992: 	case O_LIMIT: /* limit number of sessions */
  993: 	    {
  994: 		u_int16_t limit_mask = cmd->limit_mask;
  995: 		struct ipfw_flow_id id;
  996: 		ipfw_dyn_rule *parent;
  997: 
  998: 		DEB(printf("installing dyn-limit rule %d\n", cmd->conn_limit);)
  999: 
 1000: 		id.dst_ip = id.src_ip = 0;
 1001: 		id.dst_port = id.src_port = 0;
 1002: 		id.proto = args->f_id.proto;
 1003: 
 1004: 		if (limit_mask & DYN_SRC_ADDR)
 1005: 			id.src_ip = args->f_id.src_ip;
 1006: 		if (limit_mask & DYN_DST_ADDR)
 1007: 			id.dst_ip = args->f_id.dst_ip;
 1008: 		if (limit_mask & DYN_SRC_PORT)
 1009: 			id.src_port = args->f_id.src_port;
 1010: 		if (limit_mask & DYN_DST_PORT)
 1011: 			id.dst_port = args->f_id.dst_port;
 1012: 		parent = lookup_dyn_parent(&id, rule);
 1013: 		if (parent == NULL) {
 1014: 			printf("add parent failed\n");
 1015: 			return 1;
 1016: 		}
 1017: 		if (parent->count >= cmd->conn_limit) {
 1018: 			/*
 1019: 			 * See if we can remove some expired rule.
 1020: 			 */
 1021: 			remove_dyn_rule(rule, parent);
 1022: 			if (parent->count >= cmd->conn_limit) {
 1023: 				if (fw_verbose && last_log != time_second) {
 1024: 					last_log = time_second;
 1025: 					log(LOG_SECURITY | LOG_DEBUG,
 1026: 					    "drop session, too many entries\n");
 1027: 				}
 1028: 				return 1;
 1029: 			}
 1030: 		}
 1031: 		add_dyn_rule(&args->f_id, O_LIMIT, (struct ip_fw *)parent);
 1032: 	    }
 1033: 		break;
 1034: 	default:
 1035: 		printf("unknown dynamic rule type %u\n", cmd->o.opcode);
 1036: 		return 1;
 1037: 	}
 1038: 	lookup_dyn_rule(&args->f_id, NULL, NULL); /* XXX just set lifetime */
 1039: 	return 0;
 1040: }
 1041: 
 1042: /*
 1043:  * Transmit a TCP packet, containing either a RST or a keepalive.
 1044:  * When flags & TH_RST, we are sending a RST packet, because of a
 1045:  * "reset" action matched the packet.
 1046:  * Otherwise we are sending a keepalive, and flags & TH_
 1047:  */
 1048: static void
 1049: send_pkt(struct ipfw_flow_id *id, u_int32_t seq, u_int32_t ack, int flags)
 1050: {
 1051: 	struct mbuf *m;
 1052: 	struct ip *ip;
 1053: 	struct tcphdr *tcp;
 1054: 	struct route sro;	/* fake route */
 1055: 
 1056: 	MGETHDR(m, M_DONTWAIT, MT_HEADER);
 1057: 	if (m == 0)
 1058: 		return;
 1059: 	m->m_pkthdr.rcvif = (struct ifnet *)0;
 1060: 	m->m_pkthdr.len = m->m_len = sizeof(struct ip) + sizeof(struct tcphdr);
 1061: 	m->m_data += max_linkhdr;
 1062: 
 1063: 	ip = mtod(m, struct ip *);
 1064: 	bzero(ip, m->m_len);
 1065: 	tcp = (struct tcphdr *)(ip + 1); /* no IP options */
 1066: 	ip->ip_p = IPPROTO_TCP;
 1067: 	tcp->th_off = 5;
 1068: 	/*
 1069: 	 * Assume we are sending a RST (or a keepalive in the reverse
 1070: 	 * direction), swap src and destination addresses and ports.
 1071: 	 */
 1072: 	ip->ip_src.s_addr = htonl(id->dst_ip);
 1073: 	ip->ip_dst.s_addr = htonl(id->src_ip);
 1074: 	tcp->th_sport = htons(id->dst_port);
 1075: 	tcp->th_dport = htons(id->src_port);
 1076: 	if (flags & TH_RST) {	/* we are sending a RST */
 1077: 		if (flags & TH_ACK) {
 1078: 			tcp->th_seq = htonl(ack);
 1079: 			tcp->th_ack = htonl(0);
 1080: 			tcp->th_flags = TH_RST;
 1081: 		} else {
 1082: 			if (flags & TH_SYN)
 1083: 				seq++;
 1084: 			tcp->th_seq = htonl(0);
 1085: 			tcp->th_ack = htonl(seq);
 1086: 			tcp->th_flags = TH_RST | TH_ACK;
 1087: 		}
 1088: 	} else {
 1089: 		/*
 1090: 		 * We are sending a keepalive. flags & TH_SYN determines
 1091: 		 * the direction, forward if set, reverse if clear.
 1092: 		 * NOTE: seq and ack are always assumed to be correct
 1093: 		 * as set by the caller. This may be confusing...
 1094: 		 */
 1095: 		if (flags & TH_SYN) {
 1096: 			/*
 1097: 			 * we have to rewrite the correct addresses!
 1098: 			 */
 1099: 			ip->ip_dst.s_addr = htonl(id->dst_ip);
 1100: 			ip->ip_src.s_addr = htonl(id->src_ip);
 1101: 			tcp->th_dport = htons(id->dst_port);
 1102: 			tcp->th_sport = htons(id->src_port);
 1103: 		}
 1104: 		tcp->th_seq = htonl(seq);
 1105: 		tcp->th_ack = htonl(ack);
 1106: 		tcp->th_flags = TH_ACK;
 1107: 	}
 1108: 	/*
 1109: 	 * set ip_len to the payload size so we can compute
 1110: 	 * the tcp checksum on the pseudoheader
 1111: 	 * XXX check this, could save a couple of words ?
 1112: 	 */
 1113: 	ip->ip_len = htons(sizeof(struct tcphdr));
 1114: 	tcp->th_sum = in_cksum(m, m->m_pkthdr.len);
 1115: 	/*
 1116: 	 * now fill fields left out earlier
 1117: 	 */
 1118: 	ip->ip_ttl = ip_defttl;
 1119: 	ip->ip_len = m->m_pkthdr.len;
 1120: 	bzero (&sro, sizeof (sro));
 1121: 	ip_rtaddr(ip->ip_dst, &sro);
 1122: 	m->m_flags |= M_SKIP_FIREWALL;
 1123: 	ip_output(m, NULL, &sro, 0, NULL, NULL);
 1124: 	if (sro.ro_rt)
 1125: 		RTFREE(sro.ro_rt);
 1126: }
 1127: 
 1128: /*
 1129:  * sends a reject message, consuming the mbuf passed as an argument.
 1130:  */
 1131: static void
 1132: send_reject(struct ip_fw_args *args, int code, int offset, int ip_len)
 1133: {
 1134: 
 1135: 	if (code != ICMP_REJECT_RST) { /* Send an ICMP unreach */
 1136: 		/* We need the IP header in host order for icmp_error(). */
 1137: 		if (args->eh != NULL) {
 1138: 			struct ip *ip = mtod(args->m, struct ip *);
 1139: 			ip->ip_len = ntohs(ip->ip_len);
 1140: 			ip->ip_off = ntohs(ip->ip_off);
 1141: 		}
 1142: 		icmp_error(args->m, ICMP_UNREACH, code, 0L, 0);
 1143: 	} else if (offset == 0 && args->f_id.proto == IPPROTO_TCP) {
 1144: 		struct tcphdr *const tcp =
 1145: 		    L3HDR(struct tcphdr, mtod(args->m, struct ip *));
 1146: 		if ( (tcp->th_flags & TH_RST) == 0)
 1147: 			send_pkt(&(args->f_id), ntohl(tcp->th_seq),
 1148: 				ntohl(tcp->th_ack),
 1149: 				tcp->th_flags | TH_RST);
 1150: 		m_freem(args->m);
 1151: 	} else
 1152: 		m_freem(args->m);
 1153: 	args->m = NULL;
 1154: }
 1155: 
 1156: /**
 1157:  *
 1158:  * Given an ip_fw *, lookup_next_rule will return a pointer
 1159:  * to the next rule, which can be either the jump
 1160:  * target (for skipto instructions) or the next one in the list (in
 1161:  * all other cases including a missing jump target).
 1162:  * The result is also written in the "next_rule" field of the rule.
 1163:  * Backward jumps are not allowed, so start looking from the next
 1164:  * rule...
 1165:  *
 1166:  * This never returns NULL -- in case we do not have an exact match,
 1167:  * the next rule is returned. When the ruleset is changed,
 1168:  * pointers are flushed so we are always correct.
 1169:  */
 1170: 
 1171: static struct ip_fw *
 1172: lookup_next_rule(struct ip_fw *me)
 1173: {
 1174: 	struct ip_fw *rule = NULL;
 1175: 	ipfw_insn *cmd;
 1176: 
 1177: 	/* look for action, in case it is a skipto */
 1178: 	cmd = ACTION_PTR(me);
 1179: 	if (cmd->opcode == O_LOG)
 1180: 		cmd += F_LEN(cmd);
 1181: 	if ( cmd->opcode == O_SKIPTO )
 1182: 		for (rule = me->next; rule ; rule = rule->next)
 1183: 			if (rule->rulenum >= cmd->arg1)
 1184: 				break;
 1185: 	if (rule == NULL)			/* failure or not a skipto */
 1186: 		rule = me->next;
 1187: 	me->next_rule = rule;
 1188: 	return rule;
 1189: }
 1190: 
 1191: /*
 1192:  * The main check routine for the firewall.
 1193:  *
 1194:  * All arguments are in args so we can modify them and return them
 1195:  * back to the caller.
 1196:  *
 1197:  * Parameters:
 1198:  *
 1199:  *	args->m	(in/out) The packet; we set to NULL when/if we nuke it.
 1200:  *		Starts with the IP header.
 1201:  *	args->eh (in)	Mac header if present, or NULL for layer3 packet.
 1202:  *	args->oif	Outgoing interface, or NULL if packet is incoming.
 1203:  *		The incoming interface is in the mbuf. (in)
 1204:  *	args->divert_rule (in/out)
 1205:  *		Skip up to the first rule past this rule number;
 1206:  *		upon return, non-zero port number for divert or tee.
 1207:  *
 1208:  *	args->rule	Pointer to the last matching rule (in/out)
 1209:  *	args->next_hop	Socket we are forwarding to (out).
 1210:  *	args->f_id	Addresses grabbed from the packet (out)
 1211:  *
 1212:  * Return value:
 1213:  *
 1214:  *	IP_FW_PORT_DENY_FLAG	the packet must be dropped.
 1215:  *	0	The packet is to be accepted and routed normally OR
 1216:  *      	the packet was denied/rejected and has been dropped;
 1217:  *		in the latter case, *m is equal to NULL upon return.
 1218:  *	port	Divert the packet to port, with these caveats:
 1219:  *
 1220:  *		- If IP_FW_PORT_TEE_FLAG is set, tee the packet instead
 1221:  *		  of diverting it (ie, 'ipfw tee').
 1222:  *
 1223:  *		- If IP_FW_PORT_DYNT_FLAG is set, interpret the lower
 1224:  *		  16 bits as a dummynet pipe number instead of diverting
 1225:  */
 1226: 
 1227: static int
 1228: ipfw_chk(struct ip_fw_args *args)
 1229: {
 1230: 	/*
 1231: 	 * Local variables hold state during the processing of a packet.
 1232: 	 *
 1233: 	 * IMPORTANT NOTE: to speed up the processing of rules, there
 1234: 	 * are some assumption on the values of the variables, which
 1235: 	 * are documented here. Should you change them, please check
 1236: 	 * the implementation of the various instructions to make sure
 1237: 	 * that they still work.
 1238: 	 *
 1239: 	 * args->eh	The MAC header. It is non-null for a layer2
 1240: 	 *	packet, it is NULL for a layer-3 packet.
 1241: 	 *
 1242: 	 * m | args->m	Pointer to the mbuf, as received from the caller.
 1243: 	 *	It may change if ipfw_chk() does an m_pullup, or if it
 1244: 	 *	consumes the packet because it calls send_reject().
 1245: 	 *	XXX This has to change, so that ipfw_chk() never modifies
 1246: 	 *	or consumes the buffer.
 1247: 	 * ip	is simply an alias of the value of m, and it is kept
 1248: 	 *	in sync with it (the packet is	supposed to start with
 1249: 	 *	the ip header).
 1250: 	 */
 1251: 	struct mbuf *m = args->m;
 1252: 	struct ip *ip = mtod(m, struct ip *);
 1253: 
 1254: 	/*
 1255: 	 * oif | args->oif	If NULL, ipfw_chk has been called on the
 1256: 	 *	inbound path (ether_input, bdg_forward, ip_input).
 1257: 	 *	If non-NULL, ipfw_chk has been called on the outbound path
 1258: 	 *	(ether_output, ip_output).
 1259: 	 */
 1260: 	struct ifnet *oif = args->oif;
 1261: 
 1262: 	struct ip_fw *f = NULL;		/* matching rule */
 1263: 	int retval = 0;
 1264: 
 1265: 	/*
 1266: 	 * hlen	The length of the IPv4 header.
 1267: 	 *	hlen >0 means we have an IPv4 packet.
 1268: 	 */
 1269: 	u_int hlen = 0;		/* hlen >0 means we have an IP pkt */
 1270: 
 1271: 	/*
 1272: 	 * offset	The offset of a fragment. offset != 0 means that
 1273: 	 *	we have a fragment at this offset of an IPv4 packet.
 1274: 	 *	offset == 0 means that (if this is an IPv4 packet)
 1275: 	 *	this is the first or only fragment.
 1276: 	 */
 1277: 	u_short offset = 0;
 1278: 
 1279: 	/*
 1280: 	 * Local copies of addresses. They are only valid if we have
 1281: 	 * an IP packet.
 1282: 	 *
 1283: 	 * proto	The protocol. Set to 0 for non-ip packets,
 1284: 	 *	or to the protocol read from the packet otherwise.
 1285: 	 *	proto != 0 means that we have an IPv4 packet.
 1286: 	 *
 1287: 	 * src_port, dst_port	port numbers, in HOST format. Only
 1288: 	 *	valid for TCP and UDP packets.
 1289: 	 *
 1290: 	 * src_ip, dst_ip	ip addresses, in NETWORK format.
 1291: 	 *	Only valid for IPv4 packets.
 1292: 	 */
 1293: 	u_int8_t proto;
 1294: 	u_int16_t src_port = 0, dst_port = 0;	/* NOTE: host format	*/
 1295: 	struct in_addr src_ip, dst_ip;		/* NOTE: network format	*/
 1296: 	u_int16_t ip_len=0;
 1297: 	int dyn_dir = MATCH_UNKNOWN;
 1298: 	ipfw_dyn_rule *q = NULL;
 1299: 
 1300: 	if (m->m_flags & M_SKIP_FIREWALL)
 1301: 		return 0;	/* accept */
 1302: 	/*
 1303: 	 * dyn_dir = MATCH_UNKNOWN when rules unchecked,
 1304: 	 * 	MATCH_NONE when checked and not matched (q = NULL),
 1305: 	 *	MATCH_FORWARD or MATCH_REVERSE otherwise (q != NULL)
 1306: 	 */
 1307: 
 1308: 	if (args->eh == NULL ||		/* layer 3 packet */
 1309: 		( m->m_pkthdr.len >= sizeof(struct ip) &&
 1310: 		    ntohs(args->eh->ether_type) == ETHERTYPE_IP))
 1311: 			hlen = ip->ip_hl << 2;
 1312: 
 1313: 	/*
 1314: 	 * Collect parameters into local variables for faster matching.
 1315: 	 */
 1316: 	if (hlen == 0) {	/* do not grab addresses for non-ip pkts */
 1317: 		proto = args->f_id.proto = 0;	/* mark f_id invalid */
 1318: 		goto after_ip_checks;
 1319: 	}
 1320: 
 1321: 	proto = args->f_id.proto = ip->ip_p;
 1322: 	src_ip = ip->ip_src;
 1323: 	dst_ip = ip->ip_dst;
 1324: 	if (args->eh != NULL) { /* layer 2 packets are as on the wire */
 1325: 		offset = ntohs(ip->ip_off) & IP_OFFMASK;
 1326: 		ip_len = ntohs(ip->ip_len);
 1327: 	} else {
 1328: 		offset = ip->ip_off & IP_OFFMASK;
 1329: 		ip_len = ip->ip_len;
 1330: 	}
 1331: 
 1332: #define PULLUP_TO(len)						\
 1333: 		do {						\
 1334: 			if ((m)->m_len < (len)) {		\
 1335: 			    args->m = m = m_pullup(m, (len));	\
 1336: 			    if (m == 0)				\
 1337: 				goto pullup_failed;		\
 1338: 			    ip = mtod(m, struct ip *);		\
 1339: 			}					\
 1340: 		} while (0)
 1341: 
 1342: 	if (offset == 0) {
 1343: 		switch (proto) {
 1344: 		case IPPROTO_TCP:
 1345: 		    {
 1346: 			struct tcphdr *tcp;
 1347: 
 1348: 			PULLUP_TO(hlen + sizeof(struct tcphdr));
 1349: 			tcp = L3HDR(struct tcphdr, ip);
 1350: 			dst_port = tcp->th_dport;
 1351: 			src_port = tcp->th_sport;
 1352: 			args->f_id.flags = tcp->th_flags;
 1353: 			}
 1354: 			break;
 1355: 
 1356: 		case IPPROTO_UDP:
 1357: 		    {
 1358: 			struct udphdr *udp;
 1359: 
 1360: 			PULLUP_TO(hlen + sizeof(struct udphdr));
 1361: 			udp = L3HDR(struct udphdr, ip);
 1362: 			dst_port = udp->uh_dport;
 1363: 			src_port = udp->uh_sport;
 1364: 			}
 1365: 			break;
 1366: 
 1367: 		case IPPROTO_ICMP:
 1368: 			PULLUP_TO(hlen + 4);	/* type, code and checksum. */
 1369: 			args->f_id.flags = L3HDR(struct icmp, ip)->icmp_type;
 1370: 			break;
 1371: 
 1372: 		default:
 1373: 			break;
 1374: 		}
 1375: #undef PULLUP_TO
 1376: 	}
 1377: 
 1378: 	args->f_id.src_ip = ntohl(src_ip.s_addr);
 1379: 	args->f_id.dst_ip = ntohl(dst_ip.s_addr);
 1380: 	args->f_id.src_port = src_port = ntohs(src_port);
 1381: 	args->f_id.dst_port = dst_port = ntohs(dst_port);
 1382: 
 1383: after_ip_checks:
 1384: 	if (args->rule) {
 1385: 		/*
 1386: 		 * Packet has already been tagged. Look for the next rule
 1387: 		 * to restart processing.
 1388: 		 *
 1389: 		 * If fw_one_pass != 0 then just accept it.
 1390: 		 * XXX should not happen here, but optimized out in
 1391: 		 * the caller.
 1392: 		 */
 1393: 		if (fw_one_pass)
 1394: 			return 0;
 1395: 
 1396: 		f = args->rule->next_rule;
 1397: 		if (f == NULL)
 1398: 			f = lookup_next_rule(args->rule);
 1399: 	} else {
 1400: 		/*
 1401: 		 * Find the starting rule. It can be either the first
 1402: 		 * one, or the one after divert_rule if asked so.
 1403: 		 */
 1404: 		int skipto = args->divert_rule;
 1405: 
 1406: 		f = layer3_chain;
 1407: 		if (args->eh == NULL && skipto != 0) {
 1408: 			if (skipto >= IPFW_DEFAULT_RULE)
 1409: 				return(IP_FW_PORT_DENY_FLAG); /* invalid */
 1410: 			while (f && f->rulenum <= skipto)
 1411: 				f = f->next;
 1412: 			if (f == NULL)	/* drop packet */
 1413: 				return(IP_FW_PORT_DENY_FLAG);
 1414: 		}
 1415: 	}
 1416: 	args->divert_rule = 0;	/* reset to avoid confusion later */
 1417: 
 1418: 	/*
 1419: 	 * Now scan the rules, and parse microinstructions for each rule.
 1420: 	 */
 1421: 	for (; f; f = f->next) {
 1422: 		int l, cmdlen;
 1423: 		ipfw_insn *cmd;
 1424: 		int skip_or; /* skip rest of OR block */
 1425: 
 1426: again:
 1427: 		if (set_disable & (1 << f->set) )
 1428: 			continue;
 1429: 
 1430: 		skip_or = 0;
 1431: 		for (l = f->cmd_len, cmd = f->cmd ; l > 0 ;
 1432: 		    l -= cmdlen, cmd += cmdlen) {
 1433: 			int match;
 1434: 
 1435: 			/*
 1436: 			 * check_body is a jump target used when we find a
 1437: 			 * CHECK_STATE, and need to jump to the body of
 1438: 			 * the target rule.
 1439: 			 */
 1440: 
 1441: check_body:
 1442: 			cmdlen = F_LEN(cmd);
 1443: 			/*
 1444: 			 * An OR block (insn_1 || .. || insn_n) has the
 1445: 			 * F_OR bit set in all but the last instruction.
 1446: 			 * The first match will set "skip_or", and cause
 1447: 			 * the following instructions to be skipped until
 1448: 			 * past the one with the F_OR bit clear.
 1449: 			 */
 1450: 			if (skip_or) {		/* skip this instruction */
 1451: 				if ((cmd->len & F_OR) == 0)
 1452: 					skip_or = 0;	/* next one is good */
 1453: 				continue;
 1454: 			}
 1455: 			match = 0; /* set to 1 if we succeed */
 1456: 
 1457: 			switch (cmd->opcode) {
 1458: 			/*
 1459: 			 * The first set of opcodes compares the packet's
 1460: 			 * fields with some pattern, setting 'match' if a
 1461: 			 * match is found. At the end of the loop there is
 1462: 			 * logic to deal with F_NOT and F_OR flags associated
 1463: 			 * with the opcode.
 1464: 			 */
 1465: 			case O_NOP:
 1466: 				match = 1;
 1467: 				break;
 1468: 
 1469: 			case O_FORWARD_MAC:
 1470: 				printf("ipfw: opcode %d unimplemented\n",
 1471: 				    cmd->opcode);
 1472: 				break;
 1473: 
 1474: 			case O_GID:
 1475: 			case O_UID:
 1476: 				/*
 1477: 				 * We only check offset == 0 && proto != 0,
 1478: 				 * as this ensures that we have an IPv4
 1479: 				 * packet with the ports info.
 1480: 				 */
 1481: 				if (offset!=0)
 1482: 					break;
 1483: 			    {
 1484: 				struct inpcbinfo *pi;
 1485: 				int wildcard;
 1486: 				struct inpcb *pcb;
 1487: 
 1488: 				if (proto == IPPROTO_TCP) {
 1489: 					wildcard = 0;
 1490: 					pi = &tcbinfo[mycpu->gd_cpuid];
 1491: 				} else if (proto == IPPROTO_UDP) {
 1492: 					wildcard = 1;
 1493: 					pi = &udbinfo;
 1494: 				} else
 1495: 					break;
 1496: 
 1497: 				pcb =  (oif) ?
 1498: 					in_pcblookup_hash(pi,
 1499: 					    dst_ip, htons(dst_port),
 1500: 					    src_ip, htons(src_port),
 1501: 					    wildcard, oif) :
 1502: 					in_pcblookup_hash(pi,
 1503: 					    src_ip, htons(src_port),
 1504: 					    dst_ip, htons(dst_port),
 1505: 					    wildcard, NULL);
 1506: 
 1507: 				if (pcb == NULL || pcb->inp_socket == NULL)
 1508: 					break;
 1509: #if defined(__DragonFly__) || (defined(__FreeBSD__) && __FreeBSD_version < 500034)
 1510: #define socheckuid(a,b)	((a)->so_cred->cr_uid != (b))
 1511: #endif
 1512: 				if (cmd->opcode == O_UID) {
 1513: 					match =
 1514: 					  !socheckuid(pcb->inp_socket,
 1515: 					   (uid_t)((ipfw_insn_u32 *)cmd)->d[0]);
 1516: 				} else  {
 1517: 					match = groupmember(
 1518: 					    (uid_t)((ipfw_insn_u32 *)cmd)->d[0],
 1519: 					    pcb->inp_socket->so_cred);
 1520: 				}
 1521: 			    }
 1522: 				break;
 1523: 
 1524: 			case O_RECV:
 1525: 				match = iface_match(m->m_pkthdr.rcvif,
 1526: 				    (ipfw_insn_if *)cmd);
 1527: 				break;
 1528: 
 1529: 			case O_XMIT:
 1530: 				match = iface_match(oif, (ipfw_insn_if *)cmd);
 1531: 				break;
 1532: 
 1533: 			case O_VIA:
 1534: 				match = iface_match(oif ? oif :
 1535: 				    m->m_pkthdr.rcvif, (ipfw_insn_if *)cmd);
 1536: 				break;
 1537: 
 1538: 			case O_MACADDR2:
 1539: 				if (args->eh != NULL) {	/* have MAC header */
 1540: 					u_int32_t *want = (u_int32_t *)
 1541: 						((ipfw_insn_mac *)cmd)->addr;
 1542: 					u_int32_t *mask = (u_int32_t *)
 1543: 						((ipfw_insn_mac *)cmd)->mask;
 1544: 					u_int32_t *hdr = (u_int32_t *)args->eh;
 1545: 
 1546: 					match =
 1547: 					    ( want[0] == (hdr[0] & mask[0]) &&
 1548: 					      want[1] == (hdr[1] & mask[1]) &&
 1549: 					      want[2] == (hdr[2] & mask[2]) );
 1550: 				}
 1551: 				break;
 1552: 
 1553: 			case O_MAC_TYPE:
 1554: 				if (args->eh != NULL) {
 1555: 					u_int16_t t =
 1556: 					    ntohs(args->eh->ether_type);
 1557: 					u_int16_t *p =
 1558: 					    ((ipfw_insn_u16 *)cmd)->ports;
 1559: 					int i;
 1560: 
 1561: 					for (i = cmdlen - 1; !match && i>0;
 1562: 					    i--, p += 2)
 1563: 						match = (t>=p[0] && t<=p[1]);
 1564: 				}
 1565: 				break;
 1566: 
 1567: 			case O_FRAG:
 1568: 				match = (hlen > 0 && offset != 0);
 1569: 				break;
 1570: 
 1571: 			case O_IN:	/* "out" is "not in" */
 1572: 				match = (oif == NULL);
 1573: 				break;
 1574: 
 1575: 			case O_LAYER2:
 1576: 				match = (args->eh != NULL);
 1577: 				break;
 1578: 
 1579: 			case O_PROTO:
 1580: 				/*
 1581: 				 * We do not allow an arg of 0 so the
 1582: 				 * check of "proto" only suffices.
 1583: 				 */
 1584: 				match = (proto == cmd->arg1);
 1585: 				break;
 1586: 
 1587: 			case O_IP_SRC:
 1588: 				match = (hlen > 0 &&
 1589: 				    ((ipfw_insn_ip *)cmd)->addr.s_addr ==
 1590: 				    src_ip.s_addr);
 1591: 				break;
 1592: 
 1593: 			case O_IP_SRC_MASK:
 1594: 				match = (hlen > 0 &&
 1595: 				    ((ipfw_insn_ip *)cmd)->addr.s_addr ==
 1596: 				     (src_ip.s_addr &
 1597: 				     ((ipfw_insn_ip *)cmd)->mask.s_addr));
 1598: 				break;
 1599: 
 1600: 			case O_IP_SRC_ME:
 1601: 				if (hlen > 0) {
 1602: 					struct ifnet *tif;
 1603: 
 1604: 					INADDR_TO_IFP(src_ip, tif);
 1605: 					match = (tif != NULL);
 1606: 				}
 1607: 				break;
 1608: 
 1609: 			case O_IP_DST_SET:
 1610: 			case O_IP_SRC_SET:
 1611: 				if (hlen > 0) {
 1612: 					u_int32_t *d = (u_int32_t *)(cmd+1);
 1613: 					u_int32_t addr =
 1614: 					    cmd->opcode == O_IP_DST_SET ?
 1615: 						args->f_id.dst_ip :
 1616: 						args->f_id.src_ip;
 1617: 
 1618: 					    if (addr < d[0])
 1619: 						    break;
 1620: 					    addr -= d[0]; /* subtract base */
 1621: 					    match = (addr < cmd->arg1) &&
 1622: 						( d[ 1 + (addr>>5)] &
 1623: 						  (1<<(addr & 0x1f)) );
 1624: 				}
 1625: 				break;
 1626: 
 1627: 			case O_IP_DST:
 1628: 				match = (hlen > 0 &&
 1629: 				    ((ipfw_insn_ip *)cmd)->addr.s_addr ==
 1630: 				    dst_ip.s_addr);
 1631: 				break;
 1632: 
 1633: 			case O_IP_DST_MASK:
 1634: 				match = (hlen > 0) &&
 1635: 				    (((ipfw_insn_ip *)cmd)->addr.s_addr ==
 1636: 				     (dst_ip.s_addr &
 1637: 				     ((ipfw_insn_ip *)cmd)->mask.s_addr));
 1638: 				break;
 1639: 
 1640: 			case O_IP_DST_ME:
 1641: 				if (hlen > 0) {
 1642: 					struct ifnet *tif;
 1643: 
 1644: 					INADDR_TO_IFP(dst_ip, tif);
 1645: 					match = (tif != NULL);
 1646: 				}
 1647: 				break;
 1648: 
 1649: 			case O_IP_SRCPORT:
 1650: 			case O_IP_DSTPORT:
 1651: 				/*
 1652: 				 * offset == 0 && proto != 0 is enough
 1653: 				 * to guarantee that we have an IPv4
 1654: 				 * packet with port info.
 1655: 				 */
 1656: 				if ((proto==IPPROTO_UDP || proto==IPPROTO_TCP)
 1657: 				    && offset == 0) {
 1658: 					u_int16_t x =
 1659: 					    (cmd->opcode == O_IP_SRCPORT) ?
 1660: 						src_port : dst_port ;
 1661: 					u_int16_t *p =
 1662: 					    ((ipfw_insn_u16 *)cmd)->ports;
 1663: 					int i;
 1664: 
 1665: 					for (i = cmdlen - 1; !match && i>0;
 1666: 					    i--, p += 2)
 1667: 						match = (x>=p[0] && x<=p[1]);
 1668: 				}
 1669: 				break;
 1670: 
 1671: 			case O_ICMPTYPE:
 1672: 				match = (offset == 0 && proto==IPPROTO_ICMP &&
 1673: 				    icmptype_match(ip, (ipfw_insn_u32 *)cmd) );
 1674: 				break;
 1675: 
 1676: 			case O_IPOPT:
 1677: 				match = (hlen > 0 && ipopts_match(ip, cmd) );
 1678: 				break;
 1679: 
 1680: 			case O_IPVER:
 1681: 				match = (hlen > 0 && cmd->arg1 == ip->ip_v);
 1682: 				break;
 1683: 
 1684: 			case O_IPTTL:
 1685: 				match = (hlen > 0 && cmd->arg1 == ip->ip_ttl);
 1686: 				break;
 1687: 
 1688: 			case O_IPID:
 1689: 				match = (hlen > 0 &&
 1690: 				    cmd->arg1 == ntohs(ip->ip_id));
 1691: 				break;
 1692: 
 1693: 			case O_IPLEN:
 1694: 				match = (hlen > 0 && cmd->arg1 == ip_len);
 1695: 				break;
 1696: 
 1697: 			case O_IPPRECEDENCE:
 1698: 				match = (hlen > 0 &&
 1699: 				    (cmd->arg1 == (ip->ip_tos & 0xe0)) );
 1700: 				break;
 1701: 
 1702: 			case O_IPTOS:
 1703: 				match = (hlen > 0 &&
 1704: 				    flags_match(cmd, ip->ip_tos));
 1705: 				break;
 1706: 
 1707: 			case O_TCPFLAGS:
 1708: 				match = (proto == IPPROTO_TCP && offset == 0 &&
 1709: 				    flags_match(cmd,
 1710: 					L3HDR(struct tcphdr,ip)->th_flags));
 1711: 				break;
 1712: 
 1713: 			case O_TCPOPTS:
 1714: 				match = (proto == IPPROTO_TCP && offset == 0 &&
 1715: 				    tcpopts_match(ip, cmd));
 1716: 				break;
 1717: 
 1718: 			case O_TCPSEQ:
 1719: 				match = (proto == IPPROTO_TCP && offset == 0 &&
 1720: 				    ((ipfw_insn_u32 *)cmd)->d[0] ==
 1721: 					L3HDR(struct tcphdr,ip)->th_seq);
 1722: 				break;
 1723: 
 1724: 			case O_TCPACK:
 1725: 				match = (proto == IPPROTO_TCP && offset == 0 &&
 1726: 				    ((ipfw_insn_u32 *)cmd)->d[0] ==
 1727: 					L3HDR(struct tcphdr,ip)->th_ack);
 1728: 				break;
 1729: 
 1730: 			case O_TCPWIN:
 1731: 				match = (proto == IPPROTO_TCP && offset == 0 &&
 1732: 				    cmd->arg1 ==
 1733: 					L3HDR(struct tcphdr,ip)->th_win);
 1734: 				break;
 1735: 
 1736: 			case O_ESTAB:
 1737: 				/* reject packets which have SYN only */
 1738: 				/* XXX should i also check for TH_ACK ? */
 1739: 				match = (proto == IPPROTO_TCP && offset == 0 &&
 1740: 				    (L3HDR(struct tcphdr,ip)->th_flags &
 1741: 				     (TH_RST | TH_ACK | TH_SYN)) != TH_SYN);
 1742: 				break;
 1743: 
 1744: 			case O_LOG:
 1745: 				if (fw_verbose)
 1746: 					ipfw_log(f, hlen, args->eh, m, oif);
 1747: 				match = 1;
 1748: 				break;
 1749: 
 1750: 			case O_PROB:
 1751: 				match = (random()<((ipfw_insn_u32 *)cmd)->d[0]);
 1752: 				break;
 1753: 
 1754: 			/*
 1755: 			 * The second set of opcodes represents 'actions',
 1756: 			 * i.e. the terminal part of a rule once the packet
 1757: 			 * matches all previous patterns.
 1758: 			 * Typically there is only one action for each rule,
 1759: 			 * and the opcode is stored at the end of the rule
 1760: 			 * (but there are exceptions -- see below).
 1761: 			 *
 1762: 			 * In general, here we set retval and terminate the
 1763: 			 * outer loop (would be a 'break 3' in some language,
 1764: 			 * but we need to do a 'goto done').
 1765: 			 *
 1766: 			 * Exceptions:
 1767: 			 * O_COUNT and O_SKIPTO actions:
 1768: 			 *   instead of terminating, we jump to the next rule
 1769: 			 *   ('goto next_rule', equivalent to a 'break 2'),
 1770: 			 *   or to the SKIPTO target ('goto again' after
 1771: 			 *   having set f, cmd and l), respectively.
 1772: 			 *
 1773: 			 * O_LIMIT and O_KEEP_STATE: these opcodes are
 1774: 			 *   not real 'actions', and are stored right
 1775: 			 *   before the 'action' part of the rule.
 1776: 			 *   These opcodes try to install an entry in the
 1777: 			 *   state tables; if successful, we continue with
 1778: 			 *   the next opcode (match=1; break;), otherwise
 1779: 			 *   the packet *   must be dropped
 1780: 			 *   ('goto done' after setting retval);
 1781: 			 *
 1782: 			 * O_PROBE_STATE and O_CHECK_STATE: these opcodes
 1783: 			 *   cause a lookup of the state table, and a jump
 1784: 			 *   to the 'action' part of the parent rule
 1785: 			 *   ('goto check_body') if an entry is found, or
 1786: 			 *   (CHECK_STATE only) a jump to the next rule if
 1787: 			 *   the entry is not found ('goto next_rule').
 1788: 			 *   The result of the lookup is cached to make
 1789: 			 *   further instances of these opcodes are
 1790: 			 *   effectively NOPs.
 1791: 			 */
 1792: 			case O_LIMIT:
 1793: 			case O_KEEP_STATE:
 1794: 				if (install_state(f,
 1795: 				    (ipfw_insn_limit *)cmd, args)) {
 1796: 					retval = IP_FW_PORT_DENY_FLAG;
 1797: 					goto done; /* error/limit violation */
 1798: 				}
 1799: 				match = 1;
 1800: 				break;
 1801: 
 1802: 			case O_PROBE_STATE:
 1803: 			case O_CHECK_STATE:
 1804: 				/*
 1805: 				 * dynamic rules are checked at the first
 1806: 				 * keep-state or check-state occurrence,
 1807: 				 * with the result being stored in dyn_dir.
 1808: 				 * The compiler introduces a PROBE_STATE
 1809: 				 * instruction for us when we have a
 1810: 				 * KEEP_STATE (because PROBE_STATE needs
 1811: 				 * to be run first).
 1812: 				 */
 1813: 				if (dyn_dir == MATCH_UNKNOWN &&
 1814: 				    (q = lookup_dyn_rule(&args->f_id,
 1815: 				     &dyn_dir, proto == IPPROTO_TCP ?
 1816: 					L3HDR(struct tcphdr, ip) : NULL))
 1817: 					!= NULL) {
 1818: 					/*
 1819: 					 * Found dynamic entry, update stats
 1820: 					 * and jump to the 'action' part of
 1821: 					 * the parent rule.
 1822: 					 */
 1823: 					q->pcnt++;
 1824: 					q->bcnt += ip_len;
 1825: 					f = q->rule;
 1826: 					cmd = ACTION_PTR(f);
 1827: 					l = f->cmd_len - f->act_ofs;
 1828: 					goto check_body;
 1829: 				}
 1830: 				/*
 1831: 				 * Dynamic entry not found. If CHECK_STATE,
 1832: 				 * skip to next rule, if PROBE_STATE just
 1833: 				 * ignore and continue with next opcode.
 1834: 				 */
 1835: 				if (cmd->opcode == O_CHECK_STATE)
 1836: 					goto next_rule;
 1837: 				match = 1;
 1838: 				break;
 1839: 
 1840: 			case O_ACCEPT:
 1841: 				retval = 0;	/* accept */
 1842: 				goto done;
 1843: 
 1844: 			case O_PIPE:
 1845: 			case O_QUEUE:
 1846: 				args->rule = f; /* report matching rule */
 1847: 				retval = cmd->arg1 | IP_FW_PORT_DYNT_FLAG;
 1848: 				goto done;
 1849: 
 1850: 			case O_DIVERT:
 1851: 			case O_TEE:
 1852: 				if (args->eh) /* not on layer 2 */
 1853: 					break;
 1854: 				args->divert_rule = f->rulenum;
 1855: 				retval = (cmd->opcode == O_DIVERT) ?
 1856: 				    cmd->arg1 :
 1857: 				    cmd->arg1 | IP_FW_PORT_TEE_FLAG;
 1858: 				goto done;
 1859: 
 1860: 			case O_COUNT:
 1861: 			case O_SKIPTO:
 1862: 				f->pcnt++;	/* update stats */
 1863: 				f->bcnt += ip_len;
 1864: 				f->timestamp = time_second;
 1865: 				if (cmd->opcode == O_COUNT)
 1866: 					goto next_rule;
 1867: 				/* handle skipto */
 1868: 				if (f->next_rule == NULL)
 1869: 					lookup_next_rule(f);
 1870: 				f = f->next_rule;
 1871: 				goto again;
 1872: 
 1873: 			case O_REJECT:
 1874: 				/*
 1875: 				 * Drop the packet and send a reject notice
 1876: 				 * if the packet is not ICMP (or is an ICMP
 1877: 				 * query), and it is not multicast/broadcast.
 1878: 				 */
 1879: 				if (hlen > 0 &&
 1880: 				    (proto != IPPROTO_ICMP ||
 1881: 				     is_icmp_query(ip)) &&
 1882: 				    !(m->m_flags & (M_BCAST|M_MCAST)) &&
 1883: 				    !IN_MULTICAST(ntohl(dst_ip.s_addr))) {
 1884: 					send_reject(args, cmd->arg1,
 1885: 					    offset,ip_len);
 1886: 					m = args->m;
 1887: 				}
 1888: 				/* FALLTHROUGH */
 1889: 			case O_DENY:
 1890: 				retval = IP_FW_PORT_DENY_FLAG;
 1891: 				goto done;
 1892: 
 1893: 			case O_FORWARD_IP:
 1894: 				if (args->eh)	/* not valid on layer2 pkts */
 1895: 					break;
 1896: 				if (!q || dyn_dir == MATCH_FORWARD)
 1897: 					args->next_hop =
 1898: 					    &((ipfw_insn_sa *)cmd)->sa;
 1899: 				retval = 0;
 1900: 				goto done;
 1901: 
 1902: 			default:
 1903: 				panic("-- unknown opcode %d\n", cmd->opcode);
 1904: 			} /* end of switch() on opcodes */
 1905: 
 1906: 			if (cmd->len & F_NOT)
 1907: 				match = !match;
 1908: 
 1909: 			if (match) {
 1910: 				if (cmd->len & F_OR)
 1911: 					skip_or = 1;
 1912: 			} else {
 1913: 				if (!(cmd->len & F_OR)) /* not an OR block, */
 1914: 					break;		/* try next rule    */
 1915: 			}
 1916: 
 1917: 		}	/* end of inner for, scan opcodes */
 1918: 
 1919: next_rule:;		/* try next rule		*/
 1920: 
 1921: 	}		/* end of outer for, scan rules */
 1922: 	printf("+++ ipfw: ouch!, skip past end of rules, denying packet\n");
 1923: 	return(IP_FW_PORT_DENY_FLAG);
 1924: 
 1925: done:
 1926: 	/* Update statistics */
 1927: 	f->pcnt++;
 1928: 	f->bcnt += ip_len;
 1929: 	f->timestamp = time_second;
 1930: 	return retval;
 1931: 
 1932: pullup_failed:
 1933: 	if (fw_verbose)
 1934: 		printf("pullup failed\n");
 1935: 	return(IP_FW_PORT_DENY_FLAG);
 1936: }
 1937: 
 1938: /*
 1939:  * When a rule is added/deleted, clear the next_rule pointers in all rules.
 1940:  * These will be reconstructed on the fly as packets are matched.
 1941:  * Must be called at splimp().
 1942:  */
 1943: static void
 1944: flush_rule_ptrs(void)
 1945: {
 1946: 	struct ip_fw *rule;
 1947: 
 1948: 	for (rule = layer3_chain; rule; rule = rule->next)
 1949: 		rule->next_rule = NULL;
 1950: }
 1951: 
 1952: /*
 1953:  * When pipes/queues are deleted, clear the "pipe_ptr" pointer to a given
 1954:  * pipe/queue, or to all of them (match == NULL).
 1955:  * Must be called at splimp().
 1956:  */
 1957: void
 1958: flush_pipe_ptrs(struct dn_flow_set *match)
 1959: {
 1960: 	struct ip_fw *rule;
 1961: 
 1962: 	for (rule = layer3_chain; rule; rule = rule->next) {
 1963: 		ipfw_insn_pipe *cmd = (ipfw_insn_pipe *)ACTION_PTR(rule);
 1964: 
 1965: 		if (cmd->o.opcode != O_PIPE && cmd->o.opcode != O_QUEUE)
 1966: 			continue;
 1967: 		if (match == NULL || cmd->pipe_ptr == match)
 1968: 			cmd->pipe_ptr = NULL;
 1969: 	}
 1970: }
 1971: 
 1972: /*
 1973:  * Add a new rule to the list. Copy the rule into a malloc'ed area, then
 1974:  * possibly create a rule number and add the rule to the list.
 1975:  * Update the rule_number in the input struct so the caller knows it as well.
 1976:  */
 1977: static int
 1978: add_rule(struct ip_fw **head, struct ip_fw *input_rule)
 1979: {
 1980: 	struct ip_fw *rule, *f, *prev;
 1981: 	int s;
 1982: 	int l = RULESIZE(input_rule);
 1983: 
 1984: 	if (*head == NULL && input_rule->rulenum != IPFW_DEFAULT_RULE)
 1985: 		return (EINVAL);
 1986: 
 1987: 	rule = malloc(l, M_IPFW, M_WAITOK | M_ZERO);
 1988: 	if (rule == NULL)
 1989: 		return (ENOSPC);
 1990: 
 1991: 	bcopy(input_rule, rule, l);
 1992: 
 1993: 	rule->next = NULL;
 1994: 	rule->next_rule = NULL;
 1995: 
 1996: 	rule->pcnt = 0;
 1997: 	rule->bcnt = 0;
 1998: 	rule->timestamp = 0;
 1999: 
 2000: 	s = splimp();
 2001: 
 2002: 	if (*head == NULL) {	/* default rule */
 2003: 		*head = rule;
 2004: 		goto done;
 2005:         }
 2006: 
 2007: 	/*
 2008: 	 * If rulenum is 0, find highest numbered rule before the
 2009: 	 * default rule, and add autoinc_step
 2010: 	 */
 2011: 	if (autoinc_step < 1)
 2012: 		autoinc_step = 1;
 2013: 	else if (autoinc_step > 1000)
 2014: 		autoinc_step = 1000;
 2015: 	if (rule->rulenum == 0) {
 2016: 		/*
 2017: 		 * locate the highest numbered rule before default
 2018: 		 */
 2019: 		for (f = *head; f; f = f->next) {
 2020: 			if (f->rulenum == IPFW_DEFAULT_RULE)
 2021: 				break;
 2022: 			rule->rulenum = f->rulenum;
 2023: 		}
 2024: 		if (rule->rulenum < IPFW_DEFAULT_RULE - autoinc_step)
 2025: 			rule->rulenum += autoinc_step;
 2026: 		input_rule->rulenum = rule->rulenum;
 2027: 	}
 2028: 
 2029: 	/*
 2030: 	 * Now insert the new rule in the right place in the sorted list.
 2031: 	 */
 2032: 	for (prev = NULL, f = *head; f; prev = f, f = f->next) {
 2033: 		if (f->rulenum > rule->rulenum) { /* found the location */
 2034: 			if (prev) {
 2035: 				rule->next = f;
 2036: 				prev->next = rule;
 2037: 			} else { /* head insert */
 2038: 				rule->next = *head;
 2039: 				*head = rule;
 2040: 			}
 2041: 			break;
 2042: 		}
 2043: 	}
 2044: 	flush_rule_ptrs();
 2045: done:
 2046: 	static_count++;
 2047: 	static_len += l;
 2048: 	splx(s);
 2049: 	DEB(printf("++ installed rule %d, static count now %d\n",
 2050: 		rule->rulenum, static_count);)
 2051: 	return (0);
 2052: }
 2053: 
 2054: /**
 2055:  * Free storage associated with a static rule (including derived
 2056:  * dynamic rules).
 2057:  * The caller is in charge of clearing rule pointers to avoid
 2058:  * dangling pointers.
 2059:  * @return a pointer to the next entry.
 2060:  * Arguments are not checked, so they better be correct.
 2061:  * Must be called at splimp().
 2062:  */
 2063: static struct ip_fw *
 2064: delete_rule(struct ip_fw **head, struct ip_fw *prev, struct ip_fw *rule)
 2065: {
 2066: 	struct ip_fw *n;
 2067: 	int l = RULESIZE(rule);
 2068: 
 2069: 	n = rule->next;
 2070: 	remove_dyn_rule(rule, NULL /* force removal */);
 2071: 	if (prev == NULL)
 2072: 		*head = n;
 2073: 	else
 2074: 		prev->next = n;
 2075: 	static_count--;
 2076: 	static_len -= l;
 2077: 
 2078: 	if (DUMMYNET_LOADED)
 2079: 		ip_dn_ruledel_ptr(rule);
 2080: 	free(rule, M_IPFW);
 2081: 	return n;
 2082: }
 2083: 
 2084: /*
 2085:  * Deletes all rules from a chain (including the default rule
 2086:  * if the second argument is set).
 2087:  * Must be called at splimp().
 2088:  */
 2089: static void
 2090: free_chain(struct ip_fw **chain, int kill_default)
 2091: {
 2092: 	struct ip_fw *rule;
 2093: 
 2094: 	flush_rule_ptrs(); /* more efficient to do outside the loop */
 2095: 
 2096: 	while ( (rule = *chain) != NULL &&
 2097: 	    (kill_default || rule->rulenum != IPFW_DEFAULT_RULE) )
 2098: 		delete_rule(chain, NULL, rule);
 2099: }
 2100: 
 2101: /**
 2102:  * Remove all rules with given number, and also do set manipulation.
 2103:  *
 2104:  * The argument is an u_int32_t. The low 16 bit are the rule or set number,
 2105:  * the next 8 bits are the new set, the top 8 bits are the command:
 2106:  *
 2107:  *	0	delete rules with given number
 2108:  *	1	delete rules with given set number
 2109:  *	2	move rules with given number to new set
 2110:  *	3	move rules with given set number to new set
 2111:  *	4	swap sets with given numbers
 2112:  */
 2113: static int
 2114: del_entry(struct ip_fw **chain, u_int32_t arg)
 2115: {
 2116: 	struct ip_fw *prev, *rule;
 2117: 	int s;
 2118: 	u_int16_t rulenum;
 2119: 	u_int8_t cmd, new_set;
 2120: 
 2121: 	rulenum = arg & 0xffff;
 2122: 	cmd = (arg >> 24) & 0xff;
 2123: 	new_set = (arg >> 16) & 0xff;
 2124: 
 2125: 	if (cmd > 4)
 2126: 		return EINVAL;
 2127: 	if (new_set > 30)
 2128: 		return EINVAL;
 2129: 	if (cmd == 0 || cmd == 2) {
 2130: 		if (rulenum == IPFW_DEFAULT_RULE)
 2131: 			return EINVAL;
 2132: 	} else {
 2133: 		if (rulenum > 30)
 2134: 			return EINVAL;
 2135: 	}
 2136: 
 2137: 	switch (cmd) {
 2138: 	case 0:	/* delete rules with given number */
 2139: 		/*
 2140: 		 * locate first rule to delete
 2141: 		 */
 2142: 		for (prev = NULL, rule = *chain;
 2143: 		    rule && rule->rulenum < rulenum;
 2144: 		     prev = rule, rule = rule->next)
 2145: 			;
 2146: 		if (rule->rulenum != rulenum)
 2147: 			return EINVAL;
 2148: 
 2149: 		s = splimp(); /* no access to rules while removing */
 2150: 		/*
 2151: 		 * flush pointers outside the loop, then delete all matching
 2152: 		 * rules. prev remains the same throughout the cycle.
 2153: 		 */
 2154: 		flush_rule_ptrs();
 2155: 		while (rule && rule->rulenum == rulenum)
 2156: 			rule = delete_rule(chain, prev, rule);
 2157: 		splx(s);
 2158: 		break;
 2159: 
 2160: 	case 1:	/* delete all rules with given set number */
 2161: 		s = splimp();
 2162: 		flush_rule_ptrs();
 2163: 		for (prev = NULL, rule = *chain; rule ; )
 2164: 			if (rule->set == rulenum)
 2165: 				rule = delete_rule(chain, prev, rule);
 2166: 			else {
 2167: 				prev = rule;
 2168: 				rule = rule->next;
 2169: 			}
 2170: 		splx(s);
 2171: 		break;
 2172: 
 2173: 	case 2:	/* move rules with given number to new set */
 2174: 		s = splimp();
 2175: 		for (rule = *chain; rule ; rule = rule->next)
 2176: 			if (rule->rulenum == rulenum)
 2177: 				rule->set = new_set;
 2178: 		splx(s);
 2179: 		break;
 2180: 
 2181: 	case 3: /* move rules with given set number to new set */
 2182: 		s = splimp();
 2183: 		for (rule = *chain; rule ; rule = rule->next)
 2184: 			if (rule->set == rulenum)
 2185: 				rule->set = new_set;
 2186: 		splx(s);
 2187: 		break;
 2188: 
 2189: 	case 4: /* swap two sets */
 2190: 		s = splimp();
 2191: 		for (rule = *chain; rule ; rule = rule->next)
 2192: 			if (rule->set == rulenum)
 2193: 				rule->set = new_set;
 2194: 			else if (rule->set == new_set)
 2195: 				rule->set = rulenum;
 2196: 		splx(s);
 2197: 		break;
 2198: 	}
 2199: 	return 0;
 2200: }
 2201: 
 2202: /*
 2203:  * Clear counters for a specific rule.
 2204:  */
 2205: static void
 2206: clear_counters(struct ip_fw *rule, int log_only)
 2207: {
 2208: 	ipfw_insn_log *l = (ipfw_insn_log *)ACTION_PTR(rule);
 2209: 
 2210: 	if (log_only == 0) {
 2211: 		rule->bcnt = rule->pcnt = 0;
 2212: 		rule->timestamp = 0;
 2213: 	}
 2214: 	if (l->o.opcode == O_LOG)
 2215: 		l->log_left = l->max_log;
 2216: }
 2217: 
 2218: /**
 2219:  * Reset some or all counters on firewall rules.
 2220:  * @arg frwl is null to clear all entries, or contains a specific
 2221:  * rule number.
 2222:  * @arg log_only is 1 if we only want to reset logs, zero otherwise.
 2223:  */
 2224: static int
 2225: zero_entry(int rulenum, int log_only)
 2226: {
 2227: 	struct ip_fw *rule;
 2228: 	int s;
 2229: 	char *msg;
 2230: 
 2231: 	if (rulenum == 0) {
 2232: 		s = splimp();
 2233: 		norule_counter = 0;
 2234: 		for (rule = layer3_chain; rule; rule = rule->next)
 2235: 			clear_counters(rule, log_only);
 2236: 		splx(s);
 2237: 		msg = log_only ? "ipfw: All logging counts reset.\n" :
 2238: 				"ipfw: Accounting cleared.\n";
 2239: 	} else {
 2240: 		int cleared = 0;
 2241: 		/*
 2242: 		 * We can have multiple rules with the same number, so we
 2243: 		 * need to clear them all.
 2244: 		 */
 2245: 		for (rule = layer3_chain; rule; rule = rule->next)
 2246: 			if (rule->rulenum == rulenum) {
 2247: 				s = splimp();
 2248: 				while (rule && rule->rulenum == rulenum) {
 2249: 					clear_counters(rule, log_only);
 2250: 					rule = rule->next;
 2251: 				}
 2252: 				splx(s);
 2253: 				cleared = 1;
 2254: 				break;
 2255: 			}
 2256: 		if (!cleared)	/* we did not find any matching rules */
 2257: 			return (EINVAL);
 2258: 		msg = log_only ? "ipfw: Entry %d logging count reset.\n" :
 2259: 				"ipfw: Entry %d cleared.\n";
 2260: 	}
 2261: 	if (fw_verbose)
 2262: 		log(LOG_SECURITY | LOG_NOTICE, msg, rulenum);
 2263: 	return (0);
 2264: }
 2265: 
 2266: /*
 2267:  * Check validity of the structure before insert.
 2268:  * Fortunately rules are simple, so this mostly need to check rule sizes.
 2269:  */
 2270: static int
 2271: check_ipfw_struct(struct ip_fw *rule, int size)
 2272: {
 2273: 	int l, cmdlen = 0;
 2274: 	int have_action=0;
 2275: 	ipfw_insn *cmd;
 2276: 
 2277: 	if (size < sizeof(*rule)) {
 2278: 		printf("ipfw: rule too short\n");
 2279: 		return (EINVAL);
 2280: 	}
 2281: 	/* first, check for valid size */
 2282: 	l = RULESIZE(rule);
 2283: 	if (l != size) {
 2284: 		printf("ipfw: size mismatch (have %d want %d)\n", size, l);
 2285: 		return (EINVAL);
 2286: 	}
 2287: 	/*
 2288: 	 * Now go for the individual checks. Very simple ones, basically only
 2289: 	 * instruction sizes.
 2290: 	 */
 2291: 	for (l = rule->cmd_len, cmd = rule->cmd ;
 2292: 			l > 0 ; l -= cmdlen, cmd += cmdlen) {
 2293: 		cmdlen = F_LEN(cmd);
 2294: 		if (cmdlen > l) {
 2295: 			printf("ipfw: opcode %d size truncated\n",
 2296: 			    cmd->opcode);
 2297: 			return EINVAL;
 2298: 		}
 2299: 		DEB(printf("ipfw: opcode %d\n", cmd->opcode);)
 2300: 		switch (cmd->opcode) {
 2301: 		case O_NOP:
 2302: 		case O_PROBE_STATE:
 2303: 		case O_KEEP_STATE:
 2304: 		case O_PROTO:
 2305: 		case O_IP_SRC_ME:
 2306: 		case O_IP_DST_ME:
 2307: 		case O_LAYER2:
 2308: 		case O_IN:
 2309: 		case O_FRAG:
 2310: 		case O_IPOPT:
 2311: 		case O_IPLEN:
 2312: 		case O_IPID:
 2313: 		case O_IPTOS:
 2314: 		case O_IPPRECEDENCE:
 2315: 		case O_IPTTL:
 2316: 		case O_IPVER:
 2317: 		case O_TCPWIN:
 2318: 		case O_TCPFLAGS:
 2319: 		case O_TCPOPTS:
 2320: 		case O_ESTAB:
 2321: 			if (cmdlen != F_INSN_SIZE(ipfw_insn))
 2322: 				goto bad_size;
 2323: 			break;
 2324: 
 2325: 		case O_UID:
 2326: 		case O_GID:
 2327: 		case O_IP_SRC:
 2328: 		case O_IP_DST:
 2329: 		case O_TCPSEQ:
 2330: 		case O_TCPACK:
 2331: 		case O_PROB:
 2332: 		case O_ICMPTYPE:
 2333: 			if (cmdlen != F_INSN_SIZE(ipfw_insn_u32))
 2334: 				goto bad_size;
 2335: 			break;
 2336: 
 2337: 		case O_LIMIT:
 2338: 			if (cmdlen != F_INSN_SIZE(ipfw_insn_limit))
 2339: 				goto bad_size;
 2340: 			break;
 2341: 
 2342: 		case O_LOG:
 2343: 			if (cmdlen != F_INSN_SIZE(ipfw_insn_log))
 2344: 				goto bad_size;
 2345: 
 2346: 			((ipfw_insn_log *)cmd)->log_left =
 2347: 			    ((ipfw_insn_log *)cmd)->max_log;
 2348: 
 2349: 			break;
 2350: 
 2351: 		case O_IP_SRC_MASK:
 2352: 		case O_IP_DST_MASK:
 2353: 			if (cmdlen != F_INSN_SIZE(ipfw_insn_ip))
 2354: 				goto bad_size;
 2355: 			if (((ipfw_insn_ip *)cmd)->mask.s_addr == 0) {
 2356: 				printf("ipfw: opcode %d, useless rule\n",
 2357: 					cmd->opcode);
 2358: 				return EINVAL;
 2359: 			}
 2360: 			break;
 2361: 
 2362: 		case O_IP_SRC_SET:
 2363: 		case O_IP_DST_SET:
 2364: 			if (cmd->arg1 == 0 || cmd->arg1 > 256) {
 2365: 				printf("ipfw: invalid set size %d\n",
 2366: 					cmd->arg1);
 2367: 				return EINVAL;
 2368: 			}
 2369: 			if (cmdlen != F_INSN_SIZE(ipfw_insn_u32) +
 2370: 			    (cmd->arg1+31)/32 )
 2371: 				goto bad_size;
 2372: 			break;
 2373: 
 2374: 		case O_MACADDR2:
 2375: 			if (cmdlen != F_INSN_SIZE(ipfw_insn_mac))
 2376: 				goto bad_size;
 2377: 			break;
 2378: 
 2379: 		case O_MAC_TYPE:
 2380: 		case O_IP_SRCPORT:
 2381: 		case O_IP_DSTPORT: /* XXX artificial limit, 30 port pairs */
 2382: 			if (cmdlen < 2 || cmdlen > 31)
 2383: 				goto bad_size;
 2384: 			break;
 2385: 
 2386: 		case O_RECV:
 2387: 		case O_XMIT:
 2388: 		case O_VIA:
 2389: 			if (cmdlen != F_INSN_SIZE(ipfw_insn_if))
 2390: 				goto bad_size;
 2391: 			break;
 2392: 
 2393: 		case O_PIPE:
 2394: 		case O_QUEUE:
 2395: 			if (cmdlen != F_INSN_SIZE(ipfw_insn_pipe))
 2396: 				goto bad_size;
 2397: 			goto check_action;
 2398: 
 2399: 		case O_FORWARD_IP:
 2400: 			if (cmdlen != F_INSN_SIZE(ipfw_insn_sa))
 2401: 				goto bad_size;
 2402: 			goto check_action;
 2403: 
 2404: 		case O_FORWARD_MAC: /* XXX not implemented yet */
 2405: 		case O_CHECK_STATE:
 2406: 		case O_COUNT:
 2407: 		case O_ACCEPT:
 2408: 		case O_DENY:
 2409: 		case O_REJECT:
 2410: 		case O_SKIPTO:
 2411: 		case O_DIVERT:
 2412: 		case O_TEE:
 2413: 			if (cmdlen != F_INSN_SIZE(ipfw_insn))
 2414: 				goto bad_size;
 2415: check_action:
 2416: 			if (have_action) {
 2417: 				printf("ipfw: opcode %d, multiple actions"
 2418: 					" not allowed\n",
 2419: 					cmd->opcode);
 2420: 				return EINVAL;
 2421: 			}
 2422: 			have_action = 1;
 2423: 			if (l != cmdlen) {
 2424: 				printf("ipfw: opcode %d, action must be"
 2425: 					" last opcode\n",
 2426: 					cmd->opcode);
 2427: 				return EINVAL;
 2428: 			}
 2429: 			break;
 2430: 		default:
 2431: 			printf("ipfw: opcode %d, unknown opcode\n",
 2432: 				cmd->opcode);
 2433: 			return EINVAL;
 2434: 		}
 2435: 	}
 2436: 	if (have_action == 0) {
 2437: 		printf("ipfw: missing action\n");
 2438: 		return EINVAL;
 2439: 	}
 2440: 	return 0;
 2441: 
 2442: bad_size:
 2443: 	printf("ipfw: opcode %d size %d wrong\n",
 2444: 		cmd->opcode, cmdlen);
 2445: 	return EINVAL;
 2446: }
 2447: 
 2448: 
 2449: /**
 2450:  * {set|get}sockopt parser.
 2451:  */
 2452: static int
 2453: ipfw_ctl(struct sockopt *sopt)
 2454: {
 2455: 	int error, s, rulenum;
 2456: 	size_t size;
 2457: 	struct ip_fw *bp , *buf, *rule;
 2458: 
 2459: 	static u_int32_t rule_buf[255];	/* we copy the data here */
 2460: 
 2461: 	/*
 2462: 	 * Disallow modifications in really-really secure mode, but still allow
 2463: 	 * the logging counters to be reset.
 2464: 	 */
 2465: 	if (sopt->sopt_name == IP_FW_ADD ||
 2466: 	    (sopt->sopt_dir == SOPT_SET && sopt->sopt_name != IP_FW_RESETLOG)) {
 2467: #if defined(__FreeBSD__) && __FreeBSD_version >= 500034
 2468: 		error = securelevel_ge(sopt->sopt_td->td_ucred, 3);
 2469: 		if (error)
 2470: 			return (error);
 2471: #else /* FreeBSD 4.x */
 2472: 		if (securelevel >= 3)
 2473: 			return (EPERM);
 2474: #endif
 2475: 	}
 2476: 
 2477: 	error = 0;
 2478: 
 2479: 	switch (sopt->sopt_name) {
 2480: 	case IP_FW_GET:
 2481: 		/*
 2482: 		 * pass up a copy of the current rules. Static rules
 2483: 		 * come first (the last of which has number IPFW_DEFAULT_RULE),
 2484: 		 * followed by a possibly empty list of dynamic rule.
 2485: 		 * The last dynamic rule has NULL in the "next" field.
 2486: 		 */
 2487: 		s = splimp();
 2488: 		size = static_len;	/* size of static rules */
 2489: 		if (ipfw_dyn_v)		/* add size of dyn.rules */
 2490: 			size += (dyn_count * sizeof(ipfw_dyn_rule));
 2491: 
 2492: 		/*
 2493: 		 * XXX todo: if the user passes a short length just to know
 2494: 		 * how much room is needed, do not bother filling up the
 2495: 		 * buffer, just jump to the sooptcopyout.
 2496: 		 */
 2497: 		buf = malloc(size, M_TEMP, M_NOWAIT);
 2498: 		if (buf == 0) {
 2499: 			splx(s);
 2500: 			error = ENOBUFS;
 2501: 			break;
 2502: 		}
 2503: 
 2504: 		bp = buf;
 2505: 		for (rule = layer3_chain; rule ; rule = rule->next) {
 2506: 			int i = RULESIZE(rule);
 2507: 			bcopy(rule, bp, i);
 2508: 			/*
 2509: 			 * abuse 'next_rule' to store the set_disable word
 2510: 			 */
 2511: 			(u_int32_t)(((struct ip_fw *)bp)->next_rule) =
 2512: 				set_disable;
 2513: 			bp = (struct ip_fw *)((char *)bp + i);
 2514: 		}
 2515: 		if (ipfw_dyn_v) {
 2516: 			int i;
 2517: 			ipfw_dyn_rule *p, *dst, *last = NULL;
 2518: 
 2519: 			dst = (ipfw_dyn_rule *)bp;
 2520: 			for (i = 0 ; i < curr_dyn_buckets ; i++ )
 2521: 				for ( p = ipfw_dyn_v[i] ; p != NULL ;
 2522: 				    p = p->next, dst++ ) {
 2523: 					bcopy(p, dst, sizeof *p);
 2524: 					(int)dst->rule = p->rule->rulenum ;
 2525: 					/*
 2526: 					 * store a non-null value in "next".
 2527: 					 * The userland code will interpret a
 2528: 					 * NULL here as a marker
 2529: 					 * for the last dynamic rule.
 2530: 					 */
 2531: 					dst->next = dst ;
 2532: 					last = dst ;
 2533: 					dst->expire =
 2534: 					    TIME_LEQ(dst->expire, time_second) ?
 2535: 						0 : dst->expire - time_second ;
 2536: 				}
 2537: 			if (last != NULL) /* mark last dynamic rule */
 2538: 				last->next = NULL;
 2539: 		}
 2540: 		splx(s);
 2541: 
 2542: 		error = sooptcopyout(sopt, buf, size);
 2543: 		free(buf, M_TEMP);
 2544: 		break;
 2545: 
 2546: 	case IP_FW_FLUSH:
 2547: 		/*
 2548: 		 * Normally we cannot release the lock on each iteration.
 2549: 		 * We could do it here only because we start from the head all
 2550: 		 * the times so there is no risk of missing some entries.
 2551: 		 * On the other hand, the risk is that we end up with
 2552: 		 * a very inconsistent ruleset, so better keep the lock
 2553: 		 * around the whole cycle.
 2554: 		 *
 2555: 		 * XXX this code can be improved by resetting the head of
 2556: 		 * the list to point to the default rule, and then freeing
 2557: 		 * the old list without the need for a lock.
 2558: 		 */
 2559: 
 2560: 		s = splimp();
 2561: 		free_chain(&layer3_chain, 0 /* keep default rule */);
 2562: 		splx(s);
 2563: 		break;
 2564: 
 2565: 	case IP_FW_ADD:
 2566: 		rule = (struct ip_fw *)rule_buf; /* XXX do a malloc */
 2567: 		error = sooptcopyin(sopt, rule, sizeof(rule_buf),
 2568: 			sizeof(struct ip_fw) );
 2569: 		size = sopt->sopt_valsize;
 2570: 		if (error || (error = check_ipfw_struct(rule, size)))
 2571: 			break;
 2572: 
 2573: 		error = add_rule(&layer3_chain, rule);
 2574: 		size = RULESIZE(rule);
 2575: 		if (!error && sopt->sopt_dir == SOPT_GET)
 2576: 			error = sooptcopyout(sopt, rule, size);
 2577: 		break;
 2578: 
 2579: 	case IP_FW_DEL:
 2580: 		/*
 2581: 		 * IP_FW_DEL is used for deleting single rules or sets,
 2582: 		 * and (ab)used to atomically manipulate sets. Argument size
 2583: 		 * is used to distinguish between the two:
 2584: 		 *    sizeof(u_int32_t)
 2585: 		 *	delete single rule or set of rules,
 2586: 		 *	or reassign rules (or sets) to a different set.
 2587: 		 *    2*sizeof(u_int32_t)
 2588: 		 *	atomic disable/enable sets.
 2589: 		 *	first u_int32_t contains sets to be disabled,
 2590: 		 *	second u_int32_t contains sets to be enabled.
 2591: 		 */
 2592: 		error = sooptcopyin(sopt, rule_buf,
 2593: 			2*sizeof(u_int32_t), sizeof(u_int32_t));
 2594: 		if (error)
 2595: 			break;
 2596: 		size = sopt->sopt_valsize;
 2597: 		if (size == sizeof(u_int32_t))	/* delete or reassign */
 2598: 			error = del_entry(&layer3_chain, rule_buf[0]);
 2599: 		else if (size == 2*sizeof(u_int32_t)) /* set enable/disable */
 2600: 			set_disable =
 2601: 			    (set_disable | rule_buf[0]) & ~rule_buf[1] &
 2602: 			    ~(1<<31); /* set 31 always enabled */
 2603: 		else
 2604: 			error = EINVAL;
 2605: 		break;
 2606: 
 2607: 	case IP_FW_ZERO:
 2608: 	case IP_FW_RESETLOG: /* argument is an int, the rule number */
 2609: 		rulenum=0;
 2610: 
 2611: 		if (sopt->sopt_val != 0) {
 2612: 		    error = sooptcopyin(sopt, &rulenum,
 2613: 			    sizeof(int), sizeof(int));
 2614: 		    if (error)
 2615: 			break;
 2616: 		}
 2617: 		error = zero_entry(rulenum, sopt->sopt_name == IP_FW_RESETLOG);
 2618: 		break;
 2619: 
 2620: 	default:
 2621: 		printf("ipfw_ctl invalid option %d\n", sopt->sopt_name);
 2622: 		error = EINVAL;
 2623: 	}
 2624: 
 2625: 	return (error);
 2626: }
 2627: 
 2628: /**
 2629:  * dummynet needs a reference to the default rule, because rules can be
 2630:  * deleted while packets hold a reference to them. When this happens,
 2631:  * dummynet changes the reference to the default rule (it could well be a
 2632:  * NULL pointer, but this way we do not need to check for the special
 2633:  * case, plus here he have info on the default behaviour).
 2634:  */
 2635: struct ip_fw *ip_fw_default_rule;
 2636: 
 2637: /*
 2638:  * This procedure is only used to handle keepalives. It is invoked
 2639:  * every dyn_keepalive_period
 2640:  */
 2641: static void
 2642: ipfw_tick(void * __unused unused)
 2643: {
 2644: 	int i;
 2645: 	int s;
 2646: 	ipfw_dyn_rule *q;
 2647: 
 2648: 	if (dyn_keepalive == 0 || ipfw_dyn_v == NULL || dyn_count == 0)
 2649: 		goto done;
 2650: 
 2651: 	s = splimp();
 2652: 	for (i = 0 ; i < curr_dyn_buckets ; i++) {
 2653: 		for (q = ipfw_dyn_v[i] ; q ; q = q->next ) {
 2654: 			if (q->dyn_type == O_LIMIT_PARENT)
 2655: 				continue;
 2656: 			if (q->id.proto != IPPROTO_TCP)
 2657: 				continue;
 2658: 			if ( (q->state & BOTH_SYN) != BOTH_SYN)
 2659: 				continue;
 2660: 			if (TIME_LEQ( time_second+dyn_keepalive_interval,
 2661: 			    q->expire))
 2662: 				continue;	/* too early */
 2663: 			if (TIME_LEQ(q->expire, time_second))
 2664: 				continue;	/* too late, rule expired */
 2665: 
 2666: 			send_pkt(&(q->id), q->ack_rev - 1, q->ack_fwd, TH_SYN);
 2667: 			send_pkt(&(q->id), q->ack_fwd - 1, q->ack_rev, 0);
 2668: 		}
 2669: 	}
 2670: 	splx(s);
 2671: done:
 2672: 	ipfw_timeout_h = timeout(ipfw_tick, NULL, dyn_keepalive_period*hz);
 2673: }
 2674: 
 2675: static void
 2676: ipfw_init(void)
 2677: {
 2678: 	struct ip_fw default_rule;
 2679: 
 2680: 	ip_fw_chk_ptr = ipfw_chk;
 2681: 	ip_fw_ctl_ptr = ipfw_ctl;
 2682: 	layer3_chain = NULL;
 2683: 
 2684: 	bzero(&default_rule, sizeof default_rule);
 2685: 
 2686: 	default_rule.act_ofs = 0;
 2687: 	default_rule.rulenum = IPFW_DEFAULT_RULE;
 2688: 	default_rule.cmd_len = 1;
 2689: 	default_rule.set = 31;
 2690: 
 2691: 	default_rule.cmd[0].len = 1;
 2692: 	default_rule.cmd[0].opcode =
 2693: #ifdef IPFIREWALL_DEFAULT_TO_ACCEPT
 2694: 				1 ? O_ACCEPT :
 2695: #endif
 2696: 				O_DENY;
 2697: 
 2698: 	add_rule(&layer3_chain, &default_rule);
 2699: 
 2700: 	ip_fw_default_rule = layer3_chain;
 2701: 	printf("ipfw2 initialized, divert %s, "
 2702: 		"rule-based forwarding enabled, default to %s, logging ",
 2703: #ifdef IPDIVERT
 2704: 		"enabled",
 2705: #else
 2706: 		"disabled",
 2707: #endif
 2708: 		default_rule.cmd[0].opcode == O_ACCEPT ? "accept" : "deny");
 2709: 
 2710: #ifdef IPFIREWALL_VERBOSE
 2711: 	fw_verbose = 1;
 2712: #endif
 2713: #ifdef IPFIREWALL_VERBOSE_LIMIT
 2714: 	verbose_limit = IPFIREWALL_VERBOSE_LIMIT;
 2715: #endif
 2716: 	if (fw_verbose == 0)
 2717: 		printf("disabled\n");
 2718: 	else if (verbose_limit == 0)
 2719: 		printf("unlimited\n");
 2720: 	else
 2721: 		printf("limited to %d packets/entry by default\n",
 2722: 		    verbose_limit);
 2723: 	bzero(&ipfw_timeout_h, sizeof(struct callout_handle));
 2724: 	ipfw_timeout_h = timeout(ipfw_tick, NULL, hz);
 2725: }
 2726: 
 2727: static int
 2728: ipfw_modevent(module_t mod, int type, void *unused)
 2729: {
 2730: 	int s;
 2731: 	int err = 0;
 2732: 
 2733: 	switch (type) {
 2734: 	case MOD_LOAD:
 2735: 		s = splimp();
 2736: 		if (IPFW_LOADED) {
 2737: 			splx(s);
 2738: 			printf("IP firewall already loaded\n");
 2739: 			err = EEXIST;
 2740: 		} else {
 2741: 			ipfw_init();
 2742: 			splx(s);
 2743: 		}
 2744: 		break;
 2745: 
 2746: 	case MOD_UNLOAD:
 2747: #if !defined(KLD_MODULE)
 2748: 		printf("ipfw statically compiled, cannot unload\n");
 2749: 		err = EBUSY;
 2750: #else
 2751:                 s = splimp();
 2752: 		untimeout(ipfw_tick, NULL, ipfw_timeout_h);
 2753: 		ip_fw_chk_ptr = NULL;
 2754: 		ip_fw_ctl_ptr = NULL;
 2755: 		free_chain(&layer3_chain, 1 /* kill default rule */);
 2756: 		splx(s);
 2757: 		printf("IP firewall unloaded\n");
 2758: #endif
 2759: 		break;
 2760: 	default:
 2761: 		break;
 2762: 	}
 2763: 	return err;
 2764: }
 2765: 
 2766: static moduledata_t ipfwmod = {
 2767: 	"ipfw",
 2768: 	ipfw_modevent,
 2769: 	0
 2770: };
 2771: DECLARE_MODULE(ipfw, ipfwmod, SI_SUB_PSEUDO, SI_ORDER_ANY);
 2772: MODULE_VERSION(ipfw, 1);
 2773: #endif /* IPFW2 */