コード例 #1
0
ファイル: ip_fw.c プロジェクト: aniwang2013/leon-rtems
static int 
ip_fw_chk(struct ip **pip, int hlen,
	struct ifnet *oif, int ignport, struct mbuf **m)
{
	struct ip_fw_chain *chain;
	struct ip_fw *rule = NULL;
	struct ip *ip = *pip;
	struct ifnet *const rif = (*m)->m_pkthdr.rcvif;
	u_short offset = (ip->ip_off & IP_OFFMASK);
	u_short src_port, dst_port;

	/*
	 * Go down the chain, looking for enlightment
	 */
	for (chain=ip_fw_chain.lh_first; chain; chain = chain->chain.le_next) {
		register struct ip_fw *const f = chain->rule;

		/* Check direction inbound */
		if (!oif && !(f->fw_flg & IP_FW_F_IN))
			continue;

		/* Check direction outbound */
		if (oif && !(f->fw_flg & IP_FW_F_OUT))
			continue;

		/* Fragments */
		if ((f->fw_flg & IP_FW_F_FRAG) && !(ip->ip_off & IP_OFFMASK))
			continue;

		/* If src-addr doesn't match, not this rule. */
		if (((f->fw_flg & IP_FW_F_INVSRC) != 0) ^ ((ip->ip_src.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) ^ ((ip->ip_dst.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 options */
		if (f->fw_ipopt != f->fw_ipnopt && !ipopts_match(ip, f))
			continue;

		/* Check protocol; if wildcard, match */
		if (f->fw_prot == IPPROTO_IP)
			goto got_match;

		/* If different, don't match */
		if (ip->ip_p != f->fw_prot) 
			continue;

#define PULLUP_TO(len)	do {						\
			    if ((*m)->m_len < (len)			\
				&& (*m = m_pullup(*m, (len))) == 0) {	\
				    goto bogusfrag;			\
			    }						\
			    *pip = ip = mtod(*m, struct ip *);		\
			    offset = (ip->ip_off & IP_OFFMASK);		\
			} while (0)

		/* Protocol specific checks */
		switch (ip->ip_p) {
		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 (f->fw_nports != 0 ||
				    f->fw_tcpf != f->fw_tcpnf)
					continue;

				break;
			}
			PULLUP_TO(hlen + 14);
			tcp = (struct tcphdr *) ((u_long *)ip + ip->ip_hl);
			if (f->fw_tcpf != f->fw_tcpnf && !tcpflg_match(tcp, f))
				continue;
			src_port = ntohs(tcp->th_sport);
			dst_port = ntohs(tcp->th_dport);
			goto check_ports;
		    }

		case IPPROTO_UDP:
		    {
			struct udphdr *udp;

			if (offset != 0) {
				/*
				 * Port specification is unavailable -- if this
				 * rule specifies a port, we consider the rule
				 * a non-match.
				 */
				if (f->fw_nports != 0)
					continue;

				break;
			}
			PULLUP_TO(hlen + 4);
			udp = (struct udphdr *) ((u_long *)ip + ip->ip_hl);
			src_port = ntohs(udp->uh_sport);
			dst_port = ntohs(udp->uh_dport);
check_ports:
			if (!port_match(&f->fw_pts[0],
			    IP_FW_GETNSRCP(f), src_port,
			    f->fw_flg & IP_FW_F_SRNG))
				continue;
			if (!port_match(&f->fw_pts[IP_FW_GETNSRCP(f)],
			    IP_FW_GETNDSTP(f), dst_port,
			    f->fw_flg & IP_FW_F_DRNG)) 
				continue;
			break;
		    }

		case IPPROTO_ICMP:
		    {
			struct icmp *icmp;

			if (offset != 0)	/* Type isn't valid */
				break;
			PULLUP_TO(hlen + 2);
			icmp = (struct icmp *) ((u_long *)ip + ip->ip_hl);
			if (!icmptype_match(icmp, f))
				continue;
			break;
		    }
#undef PULLUP_TO

bogusfrag:
			if (fw_verbose)
				ipfw_report(NULL, ip, rif, oif);
			goto dropit;
		}

got_match:
		/* Ignore divert/tee rule if socket port is "ignport" */
		switch (f->fw_flg & IP_FW_F_COMMAND) {
		case IP_FW_F_DIVERT:
		case IP_FW_F_TEE:
			if (f->fw_divert_port == ignport)
				continue;       /* ignore this rule */
			break;
		}

		/* Update statistics */
		f->fw_pcnt += 1;
		f->fw_bcnt += ip->ip_len;
		f->timestamp = rtems_bsdnet_seconds_since_boot();

		/* Log to console if desired */
		if ((f->fw_flg & IP_FW_F_PRN) && fw_verbose)
			ipfw_report(f, ip, 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;
		case IP_FW_F_DIVERT:
			return(f->fw_divert_port);
		case IP_FW_F_TEE:
			/*
			 * XXX someday tee packet here, but beware that you
			 * can't use m_copym() or m_copypacket() because
			 * the divert input routine modifies the mbuf
			 * (and these routines only increment reference
			 * counts in the case of mbuf clusters), so need
			 * to write custom routine.
			 */
			continue;
		case IP_FW_F_SKIPTO:
#ifdef DIAGNOSTIC
			while (chain->chain.le_next
			    && chain->chain.le_next->rule->fw_number
				< f->fw_skipto_rule)
#else
			while (chain->chain.le_next->rule->fw_number
			    < f->fw_skipto_rule)
#endif
				chain = chain->chain.le_next;
			continue;
		}

		/* Deny/reject this packet using this rule */
		rule = f;
		break;
	}

#ifdef DIAGNOSTIC
	/* Rule 65535 should always be there and should always match */
	if (!chain)
		panic("ip_fw: chain");
#endif

	/*
	 * 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
	 * - The packet is not a multicast or broadcast packet
	 */
	if ((rule->fw_flg & IP_FW_F_COMMAND) == IP_FW_F_REJECT
	    && ip->ip_p != IPPROTO_ICMP
	    && !((*m)->m_flags & (M_BCAST|M_MCAST))
	    && !IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
		switch (rule->fw_reject_code) {
		case IP_FW_REJECT_RST:
		  {
			struct tcphdr *const tcp =
				(struct tcphdr *) ((u_long *)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));
			NTOHL(tip->ti_seq);
			NTOHL(tip->ti_ack);
			tip->ti_len = ip->ip_len - hlen - (tip->ti_off << 2);
			if (tcp->th_flags & TH_ACK) {
				tcp_respond(NULL, tip, *m,
				    (tcp_seq)0, ntohl(tcp->th_ack), TH_RST);
			} else {
				if (tcp->th_flags & TH_SYN)
					tip->ti_len++;
				tcp_respond(NULL, tip, *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,
			    rule->fw_reject_code, 0L, 0);
			*m = NULL;
			break;
		}
	}

dropit:
	/*
	 * Finally, drop the packet.
	 */
	if (*m) {
		m_freem(*m);
		*m = NULL;
	}
	return(0);
}
コード例 #2
0
ファイル: ip_fw.c プロジェクト: UnitedMarsupials/kame
static int 
ip_fw_chk(struct ip **pip, int hlen,
	struct ifnet *oif, u_int16_t *cookie, struct mbuf **m,
	struct ip_fw_chain **flow_id)
{
	struct ip_fw_chain *chain;
	struct ip_fw *rule = NULL;
	struct ip *ip = NULL ;
	struct ifnet *const rif = (*m)->m_pkthdr.rcvif;
	u_short offset ;
	u_short src_port, dst_port;
#ifdef	IPFW_DIVERT_RESTART
	u_int16_t skipto = *cookie;
#else
	u_int16_t ignport = ntohs(*cookie);
#endif

	if (pip) { /* normal ip packet */
	    ip = *pip;
	    offset = (ip->ip_off & IP_OFFMASK);
	} else { /* bridged or non-ip packet */
	    struct ether_header *eh = mtod(*m, struct ether_header *);
	    switch (ntohs(eh->ether_type)) {
	    case ETHERTYPE_IP :
		if ((*m)->m_len<sizeof(struct ether_header) + sizeof(struct ip))
		    goto non_ip ;
		ip = (struct ip *)(eh + 1 );
		if (ip->ip_v != IPVERSION)
		    goto non_ip ;
		hlen = ip->ip_hl << 2;
		if (hlen < sizeof(struct ip)) /* minimum header length */
		    goto non_ip ;
		if ((*m)->m_len < 14 + hlen + 14) {
		    printf("-- m_len %d, need more...\n", (*m)->m_len);
		    goto non_ip ;
		}
		offset = (ip->ip_off & IP_OFFMASK);
		break ;
	    default :
non_ip:		ip = NULL ;
		break ;
	    }
	}

	if (*flow_id) {
	    if (fw_one_pass)
		return 0 ; /* accept if passed first test */
	    /*
	     * pkt has already been tagged. Look for the next rule
	     * to restart processing
	     */
	    if ( (chain = (*flow_id)->rule->next_rule_ptr) == NULL )
		chain = (*flow_id)->rule->next_rule_ptr =
			lookup_next_rule(*flow_id) ;
		if (!chain)
		    goto dropit;
	} else {
	    chain=LIST_FIRST(&ip_fw_chain);
#ifdef IPFW_DIVERT_RESTART
	    if ( skipto ) {
		/*
		 * If we've been asked to start at a given rule immediatly,
		 * do so.
		 */
                if (skipto >= 65535)
                        goto dropit;
                while (chain && (chain->rule->fw_number <= skipto)) {
                        chain = LIST_NEXT(chain, chain);
                }
                if (! chain)
		    goto dropit;
	    }
#endif /* IPFW_DIVERT_RESTART */
        }
	*cookie = 0;
	for (; chain; chain = LIST_NEXT(chain, chain)) {
		register struct ip_fw *f;
again:
		f = chain->rule;

		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;
		}

		if (ip == NULL ) {
		    /*
		     * do relevant checks for non-ip packets:
		     * after this, only goto got_match or continue
		     */
		    struct ether_header *eh = mtod(*m, struct ether_header *);
		    int i, h, l ;
#if 0
		    printf("-- ip_fw: rule %d(%d) for %6D <- %6D type 0x%04x\n",
			    f->fw_number, IP_FW_GETNSRCP(f),
			    eh->ether_dhost, ".", eh->ether_shost, ".",
			    ntohs(eh->ether_type) );
#endif
		    /*
		     * make default rule always match or we have a panic
		     */
		    if (f->fw_number == 65535)
			goto got_match ;

		    /*
		     * temporary hack: 
		     *   udp from 0.0.0.0 means this rule applies.
		     *   1 src port is match ether type
		     *   2 src ports (interval) is match ether type
		     *   3 src ports is match ether address
		     */
		    if (f->fw_src.s_addr != 0 || f->fw_prot != IPPROTO_UDP)
			continue ;
		    switch (IP_FW_GETNSRCP(f)) {
		    case 1: /* match one type */
			if (  /* ( (f->fw_flg & IP_FW_F_INVSRC) != 0) ^ */
			      ( f->fw_pts[0] == ntohs(eh->ether_type) )  ) {
			    printf("match!\n");
			    goto got_match ;
			}
		    default:
			break ;
		    }
		    continue;
		}
		/* Fragments */
		if ((f->fw_flg & IP_FW_F_FRAG) && !(ip->ip_off & IP_OFFMASK))
			continue;

		/* If src-addr doesn't match, not this rule. */
		if (((f->fw_flg & IP_FW_F_INVSRC) != 0) ^ ((ip->ip_src.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) ^ ((ip->ip_dst.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 options */
		if (f->fw_ipopt != f->fw_ipnopt && !ipopts_match(ip, f))
			continue;

		/* Check protocol; if wildcard, match */
		if (f->fw_prot == IPPROTO_IP)
			goto got_match;

		/* If different, don't match */
		if (ip->ip_p != f->fw_prot) 
			continue;

#define PULLUP_TO(len)	do {						\
			    if ((*m)->m_len < (len) ) {			\
				if ( (*m = m_pullup(*m, (len))) == 0) 	\
				    goto bogusfrag;			\
				*pip = ip = mtod(*m, struct ip *);	\
				offset = (ip->ip_off & IP_OFFMASK);	\
			    }						\
			} while (0)

		/* Protocol specific checks */
		switch (ip->ip_p) {
		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 (f->fw_nports != 0 ||
				    f->fw_tcpf != f->fw_tcpnf)
					continue;

				break;
			}
			PULLUP_TO(hlen + 14);
			tcp = (struct tcphdr *) ((u_long *)ip + ip->ip_hl);
			if (f->fw_tcpf != f->fw_tcpnf && !tcpflg_match(tcp, f))
				continue;
			src_port = ntohs(tcp->th_sport);
			dst_port = ntohs(tcp->th_dport);
			goto check_ports;
		    }

		case IPPROTO_UDP:
		    {
			struct udphdr *udp;

			if (offset != 0) {
				/*
				 * Port specification is unavailable -- if this
				 * rule specifies a port, we consider the rule
				 * a non-match.
				 */
				if (f->fw_nports != 0)
					continue;

				break;
			}
			PULLUP_TO(hlen + 4);
			udp = (struct udphdr *) ((u_long *)ip + ip->ip_hl);
			src_port = ntohs(udp->uh_sport);
			dst_port = ntohs(udp->uh_dport);
check_ports:
			if (!port_match(&f->fw_pts[0],
			    IP_FW_GETNSRCP(f), src_port,
			    f->fw_flg & IP_FW_F_SRNG))
				continue;
			if (!port_match(&f->fw_pts[IP_FW_GETNSRCP(f)],
			    IP_FW_GETNDSTP(f), dst_port,
			    f->fw_flg & IP_FW_F_DRNG)) 
				continue;
			break;
		    }

		case IPPROTO_ICMP:
		    {
			struct icmp *icmp;

			if (offset != 0)	/* Type isn't valid */
				break;
			PULLUP_TO(hlen + 2);
			icmp = (struct icmp *) ((u_long *)ip + ip->ip_hl);
			if (!icmptype_match(icmp, f))
				continue;
			break;
		    }
#undef PULLUP_TO

bogusfrag:
			if (fw_verbose)
				ipfw_report(NULL, ip, rif, oif);
			goto dropit;
		}

got_match:
		*flow_id = chain ; /* XXX set flow id */
#ifndef IPFW_DIVERT_RESTART
		/* Ignore divert/tee rule if socket port is "ignport" */
		switch (f->fw_flg & IP_FW_F_COMMAND) {
		case IP_FW_F_DIVERT:
		case IP_FW_F_TEE:
			if (f->fw_divert_port == ignport)
				continue;       /* ignore this rule */
			break;
		}

#endif /* IPFW_DIVERT_RESTART */
		/* Update statistics */
		f->fw_pcnt += 1;
		/*
		 * note -- bridged-ip packets still have some fields
		 * in network order, including ip_len
		 */
		if (ip) {
		    if (pip)
			f->fw_bcnt += ip->ip_len;
		    else
			f->fw_bcnt += ntohs(ip->ip_len);
		}
		f->timestamp = time.tv_sec;

		/* Log to console if desired */
		if ((f->fw_flg & IP_FW_F_PRN) && fw_verbose)
			ipfw_report(f, ip, 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:
#ifdef IPFW_DIVERT_RESTART
			*cookie = f->fw_number;
#else
			*cookie = htons(f->fw_divert_port);
#endif /* IPFW_DIVERT_RESTART */
			return(f->fw_divert_port);
#endif
		case IP_FW_F_TEE:
			/*
			 * XXX someday tee packet here, but beware that you
			 * can't use m_copym() or m_copypacket() because
			 * the divert input routine modifies the mbuf
			 * (and these routines only increment reference
			 * counts in the case of mbuf clusters), so need
			 * to write custom routine.
			 */
			continue;
		case IP_FW_F_SKIPTO: /* XXX check */
		    if ( f->next_rule_ptr )
			chain = f->next_rule_ptr ;
		    else
			chain = lookup_next_rule(chain) ;
		    if (!chain)
			goto dropit;
		    goto again ;
#ifdef DUMMYNET
		case IP_FW_F_PIPE:
			return(f->fw_pipe_nr | 0x10000 );
#endif
		}

		/* Deny/reject this packet using this rule */
		rule = f;
		break;
	}

#ifdef DIAGNOSTIC
	/* Rule 65535 should always be there and should always match */
	if (!chain)
		panic("ip_fw: chain");
#endif

	/*
	 * 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 ((rule->fw_flg & IP_FW_F_COMMAND) == IP_FW_F_REJECT
	    && ip
	    && (ip->ip_p != IPPROTO_ICMP || is_icmp_query(ip))
	    && !((*m)->m_flags & (M_BCAST|M_MCAST))
	    && !IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
		switch (rule->fw_reject_code) {
		case IP_FW_REJECT_RST:
		  {
			struct tcphdr *const tcp =
				(struct tcphdr *) ((u_long *)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));
			NTOHL(tip->ti_seq);
			NTOHL(tip->ti_ack);
			tip->ti_len = ip->ip_len - hlen - (tip->ti_off << 2);
			if (tcp->th_flags & TH_ACK) {
				tcp_respond(NULL, tip, *m,
				    (tcp_seq)0, ntohl(tcp->th_ack), TH_RST);
			} else {
				if (tcp->th_flags & TH_SYN)
					tip->ti_len++;
				tcp_respond(NULL, tip, *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,
			    rule->fw_reject_code, 0L, 0);
			*m = NULL;
			break;
		}
	}

dropit:
	/*
	 * Finally, drop the packet.
	 */
	if (*m) {
		m_freem(*m);
		*m = NULL;
	}
	return(0);
}