1159 lines
28 KiB
C
1159 lines
28 KiB
C
/*
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* Copyright (c) 1993 Daniel Boulet
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* Copyright (c) 1994 Ugen J.S.Antsilevich
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* Copyright (c) 1996 Alex Nash
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*
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* Redistribution and use in source forms, with and without modification,
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* are permitted provided that this entire comment appears intact.
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*
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* Redistribution in binary form may occur without any restrictions.
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* Obviously, it would be nice if you gave credit where credit is due
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* but requiring it would be too onerous.
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*
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* This software is provided ``AS IS'' without any warranties of any kind.
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*
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* $Id: ip_fw.c,v 1.90 1998/06/21 14:53:30 bde Exp $
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*/
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/*
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* Implement IP packet firewall
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*/
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#ifndef IPFIREWALL_MODULE
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#include "opt_ipfw.h"
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#include "opt_ipdivert.h"
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#include "opt_inet.h"
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#ifndef INET
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#error IPFIREWALL requires INET.
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#endif /* INET */
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#endif
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/malloc.h>
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#include <sys/mbuf.h>
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#include <sys/kernel.h>
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#include <sys/socket.h>
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#include <sys/sysctl.h>
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#include <net/if.h>
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#include <netinet/in.h>
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#include <netinet/in_systm.h>
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#include <netinet/ip.h>
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#include <netinet/ip_var.h>
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#include <netinet/ip_icmp.h>
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#include <netinet/ip_fw.h>
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#include <netinet/tcp.h>
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#include <netinet/tcp_timer.h>
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#include <netinet/tcp_var.h>
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#include <netinet/tcpip.h>
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#include <netinet/udp.h>
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static int fw_debug = 1;
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#ifdef IPFIREWALL_VERBOSE
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static int fw_verbose = 1;
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#else
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static int fw_verbose = 0;
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#endif
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#ifdef IPFIREWALL_VERBOSE_LIMIT
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static int fw_verbose_limit = IPFIREWALL_VERBOSE_LIMIT;
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#else
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static int fw_verbose_limit = 0;
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#endif
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static LIST_HEAD (ip_fw_head, ip_fw_chain) ip_fw_chain;
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static MALLOC_DEFINE(M_IPFW, "IpFw/IpAcct", "IpFw/IpAcct chain's");
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#ifdef SYSCTL_NODE
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SYSCTL_NODE(_net_inet_ip, OID_AUTO, fw, CTLFLAG_RW, 0, "Firewall");
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SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, debug, CTLFLAG_RW, &fw_debug, 0, "");
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SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, verbose, CTLFLAG_RW, &fw_verbose, 0, "");
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SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, verbose_limit, CTLFLAG_RW, &fw_verbose_limit, 0, "");
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#endif
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#define dprintf(a) if (!fw_debug); else printf a
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#define print_ip(a) printf("%ld.%ld.%ld.%ld",(ntohl(a.s_addr)>>24)&0xFF,\
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(ntohl(a.s_addr)>>16)&0xFF,\
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(ntohl(a.s_addr)>>8)&0xFF,\
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(ntohl(a.s_addr))&0xFF);
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#define dprint_ip(a) if (!fw_debug); else print_ip(a)
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static int add_entry __P((struct ip_fw_head *chainptr, struct ip_fw *frwl));
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static int del_entry __P((struct ip_fw_head *chainptr, u_short number));
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static int zero_entry __P((struct mbuf *m));
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static struct ip_fw *check_ipfw_struct __P((struct ip_fw *m));
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static struct ip_fw *check_ipfw_mbuf __P((struct mbuf *fw));
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static __inline int
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iface_match __P((struct ifnet *ifp, union ip_fw_if *ifu,
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int byname));
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static int ipopts_match __P((struct ip *ip, struct ip_fw *f));
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static __inline int
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port_match __P((u_short *portptr, int nports, u_short port,
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int range_flag));
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static int tcpflg_match __P((struct tcphdr *tcp, struct ip_fw *f));
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static int icmptype_match __P((struct icmp * icmp, struct ip_fw * f));
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static void ipfw_report __P((struct ip_fw *f, struct ip *ip,
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struct ifnet *rif, struct ifnet *oif));
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#ifdef IPFIREWALL_MODULE
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static ip_fw_chk_t *old_chk_ptr;
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static ip_fw_ctl_t *old_ctl_ptr;
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#endif
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static int ip_fw_chk __P((struct ip **pip, int hlen,
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struct ifnet *oif, u_int16_t *cookie, struct mbuf **m));
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static int ip_fw_ctl __P((int stage, struct mbuf **mm));
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static char err_prefix[] = "ip_fw_ctl:";
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/*
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* Returns 1 if the port is matched by the vector, 0 otherwise
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*/
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static __inline int
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port_match(u_short *portptr, int nports, u_short port, int range_flag)
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{
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if (!nports)
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return 1;
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if (range_flag) {
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if (portptr[0] <= port && port <= portptr[1]) {
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return 1;
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}
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nports -= 2;
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portptr += 2;
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}
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while (nports-- > 0) {
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if (*portptr++ == port) {
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return 1;
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}
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}
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return 0;
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}
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static int
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tcpflg_match(struct tcphdr *tcp, struct ip_fw *f)
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{
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u_char flg_set, flg_clr;
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if ((f->fw_tcpf & IP_FW_TCPF_ESTAB) &&
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(tcp->th_flags & (IP_FW_TCPF_RST | IP_FW_TCPF_ACK)))
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return 1;
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flg_set = tcp->th_flags & f->fw_tcpf;
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flg_clr = tcp->th_flags & f->fw_tcpnf;
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if (flg_set != f->fw_tcpf)
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return 0;
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if (flg_clr)
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return 0;
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return 1;
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}
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static int
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icmptype_match(struct icmp *icmp, struct ip_fw *f)
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{
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int type;
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if (!(f->fw_flg & IP_FW_F_ICMPBIT))
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return(1);
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type = icmp->icmp_type;
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/* check for matching type in the bitmap */
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if (type < IP_FW_ICMPTYPES_MAX &&
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(f->fw_uar.fw_icmptypes[type / (sizeof(unsigned) * 8)] &
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(1U << (type % (8 * sizeof(unsigned))))))
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return(1);
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return(0); /* no match */
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}
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static int
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is_icmp_query(struct ip *ip)
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{
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const struct icmp *icmp;
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int icmp_type;
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icmp = (struct icmp *)((u_long *)ip + ip->ip_hl);
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icmp_type = icmp->icmp_type;
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if (icmp_type == ICMP_ECHO || icmp_type == ICMP_ROUTERSOLICIT ||
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icmp_type == ICMP_TSTAMP || icmp_type == ICMP_IREQ ||
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icmp_type == ICMP_MASKREQ)
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return(1);
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return(0);
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}
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static int
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ipopts_match(struct ip *ip, struct ip_fw *f)
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{
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register u_char *cp;
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int opt, optlen, cnt;
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u_char opts, nopts, nopts_sve;
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cp = (u_char *)(ip + 1);
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cnt = (ip->ip_hl << 2) - sizeof (struct ip);
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opts = f->fw_ipopt;
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nopts = nopts_sve = f->fw_ipnopt;
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for (; cnt > 0; cnt -= optlen, cp += optlen) {
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opt = cp[IPOPT_OPTVAL];
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if (opt == IPOPT_EOL)
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break;
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if (opt == IPOPT_NOP)
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optlen = 1;
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else {
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optlen = cp[IPOPT_OLEN];
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if (optlen <= 0 || optlen > cnt) {
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return 0; /*XXX*/
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}
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}
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switch (opt) {
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default:
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break;
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case IPOPT_LSRR:
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opts &= ~IP_FW_IPOPT_LSRR;
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nopts &= ~IP_FW_IPOPT_LSRR;
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break;
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case IPOPT_SSRR:
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opts &= ~IP_FW_IPOPT_SSRR;
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nopts &= ~IP_FW_IPOPT_SSRR;
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break;
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case IPOPT_RR:
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opts &= ~IP_FW_IPOPT_RR;
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nopts &= ~IP_FW_IPOPT_RR;
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break;
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case IPOPT_TS:
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opts &= ~IP_FW_IPOPT_TS;
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nopts &= ~IP_FW_IPOPT_TS;
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break;
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}
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if (opts == nopts)
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break;
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}
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if (opts == 0 && nopts == nopts_sve)
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return 1;
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else
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return 0;
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}
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static __inline int
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iface_match(struct ifnet *ifp, union ip_fw_if *ifu, int byname)
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{
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/* Check by name or by IP address */
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if (byname) {
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/* Check unit number (-1 is wildcard) */
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if (ifu->fu_via_if.unit != -1
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&& ifp->if_unit != ifu->fu_via_if.unit)
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return(0);
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/* Check name */
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if (strncmp(ifp->if_name, ifu->fu_via_if.name, FW_IFNLEN))
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return(0);
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return(1);
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} else if (ifu->fu_via_ip.s_addr != 0) { /* Zero == wildcard */
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struct ifaddr *ia;
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for (ia = ifp->if_addrhead.tqh_first;
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ia != NULL; ia = ia->ifa_link.tqe_next) {
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if (ia->ifa_addr == NULL)
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continue;
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if (ia->ifa_addr->sa_family != AF_INET)
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continue;
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if (ifu->fu_via_ip.s_addr != ((struct sockaddr_in *)
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(ia->ifa_addr))->sin_addr.s_addr)
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continue;
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return(1);
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}
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return(0);
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}
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return(1);
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}
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static void
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ipfw_report(struct ip_fw *f, struct ip *ip,
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struct ifnet *rif, struct ifnet *oif)
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{
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static u_int64_t counter;
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struct tcphdr *const tcp = (struct tcphdr *) ((u_long *) ip+ ip->ip_hl);
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struct udphdr *const udp = (struct udphdr *) ((u_long *) ip+ ip->ip_hl);
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struct icmp *const icmp = (struct icmp *) ((u_long *) ip + ip->ip_hl);
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int count;
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count = f ? f->fw_pcnt : ++counter;
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if (fw_verbose_limit != 0 && count > fw_verbose_limit)
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return;
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/* Print command name */
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printf("ipfw: %d ", f ? f->fw_number : -1);
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if (!f)
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printf("Refuse");
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else
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switch (f->fw_flg & IP_FW_F_COMMAND) {
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case IP_FW_F_DENY:
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printf("Deny");
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break;
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case IP_FW_F_REJECT:
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if (f->fw_reject_code == IP_FW_REJECT_RST)
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printf("Reset");
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else
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printf("Unreach");
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break;
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case IP_FW_F_ACCEPT:
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printf("Accept");
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break;
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case IP_FW_F_COUNT:
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printf("Count");
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break;
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case IP_FW_F_DIVERT:
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printf("Divert %d", f->fw_divert_port);
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break;
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case IP_FW_F_TEE:
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printf("Tee %d", f->fw_divert_port);
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break;
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case IP_FW_F_SKIPTO:
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printf("SkipTo %d", f->fw_skipto_rule);
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break;
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default:
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printf("UNKNOWN");
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break;
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}
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printf(" ");
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switch (ip->ip_p) {
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case IPPROTO_TCP:
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printf("TCP ");
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print_ip(ip->ip_src);
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if ((ip->ip_off & IP_OFFMASK) == 0)
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printf(":%d ", ntohs(tcp->th_sport));
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else
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printf(" ");
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print_ip(ip->ip_dst);
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if ((ip->ip_off & IP_OFFMASK) == 0)
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printf(":%d", ntohs(tcp->th_dport));
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break;
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case IPPROTO_UDP:
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printf("UDP ");
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print_ip(ip->ip_src);
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if ((ip->ip_off & IP_OFFMASK) == 0)
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printf(":%d ", ntohs(udp->uh_sport));
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else
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printf(" ");
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print_ip(ip->ip_dst);
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if ((ip->ip_off & IP_OFFMASK) == 0)
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printf(":%d", ntohs(udp->uh_dport));
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break;
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case IPPROTO_ICMP:
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printf("ICMP:%u.%u ", icmp->icmp_type, icmp->icmp_code);
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print_ip(ip->ip_src);
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printf(" ");
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print_ip(ip->ip_dst);
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break;
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default:
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printf("P:%d ", ip->ip_p);
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print_ip(ip->ip_src);
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printf(" ");
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print_ip(ip->ip_dst);
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break;
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}
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if (oif)
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printf(" out via %s%d", oif->if_name, oif->if_unit);
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else if (rif)
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printf(" in via %s%d", rif->if_name, rif->if_unit);
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if ((ip->ip_off & IP_OFFMASK))
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printf(" Fragment = %d",ip->ip_off & IP_OFFMASK);
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printf("\n");
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if (fw_verbose_limit != 0 && count == fw_verbose_limit)
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printf("ipfw: limit reached on rule #%d\n",
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f ? f->fw_number : -1);
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}
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/*
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* Parameters:
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*
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* ip Pointer to packet header (struct ip *)
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* hlen Packet header length
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* oif Outgoing interface, or NULL if packet is incoming
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* *cookie Skip up to the first rule past this rule number;
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* *m The packet; we set to NULL when/if we nuke it.
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*
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* Return value:
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*
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* 0 The packet is to be accepted and routed normally OR
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* the packet was denied/rejected and has been dropped;
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* in the latter case, *m is equal to NULL upon return.
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* port Divert the packet to port.
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*/
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static int
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ip_fw_chk(struct ip **pip, int hlen,
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struct ifnet *oif, u_int16_t *cookie, struct mbuf **m)
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{
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struct ip_fw_chain *chain;
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struct ip_fw *rule = NULL;
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struct ip *ip = *pip;
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struct ifnet *const rif = (*m)->m_pkthdr.rcvif;
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u_short offset = (ip->ip_off & IP_OFFMASK);
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u_short src_port, dst_port;
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u_int16_t skipto = *cookie;
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*cookie = 0;
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/*
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* Go down the chain, looking for enlightment
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* If we've been asked to start at a given rule immediatly, do so.
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*/
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chain = LIST_FIRST(&ip_fw_chain);
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if ( skipto ) {
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if (skipto >= 65535)
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goto dropit;
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while (chain && (chain->rule->fw_number <= skipto)) {
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chain = LIST_NEXT(chain, chain);
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}
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if (! chain) goto dropit;
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}
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for (; chain; chain = LIST_NEXT(chain, chain)) {
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register struct ip_fw *const f = chain->rule;
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if (oif) {
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/* Check direction outbound */
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if (!(f->fw_flg & IP_FW_F_OUT))
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continue;
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} else {
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/* Check direction inbound */
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if (!(f->fw_flg & IP_FW_F_IN))
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continue;
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}
|
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|
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/* Fragments */
|
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if ((f->fw_flg & IP_FW_F_FRAG) && !(ip->ip_off & IP_OFFMASK))
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continue;
|
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|
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/* If src-addr doesn't match, not this rule. */
|
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if (((f->fw_flg & IP_FW_F_INVSRC) != 0) ^ ((ip->ip_src.s_addr
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& f->fw_smsk.s_addr) != f->fw_src.s_addr))
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continue;
|
|
|
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/* If dest-addr doesn't match, not this rule. */
|
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if (((f->fw_flg & IP_FW_F_INVDST) != 0) ^ ((ip->ip_dst.s_addr
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& f->fw_dmsk.s_addr) != f->fw_dst.s_addr))
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continue;
|
|
|
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/* Interface check */
|
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if ((f->fw_flg & IF_FW_F_VIAHACK) == IF_FW_F_VIAHACK) {
|
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struct ifnet *const iface = oif ? oif : rif;
|
|
|
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/* Backwards compatibility hack for "via" */
|
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if (!iface || !iface_match(iface,
|
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&f->fw_in_if, f->fw_flg & IP_FW_F_OIFNAME))
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continue;
|
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} else {
|
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/* Check receive interface */
|
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if ((f->fw_flg & IP_FW_F_IIFACE)
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&& (!rif || !iface_match(rif,
|
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&f->fw_in_if, f->fw_flg & IP_FW_F_IIFNAME)))
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continue;
|
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/* Check outgoing interface */
|
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if ((f->fw_flg & IP_FW_F_OIFACE)
|
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&& (!oif || !iface_match(oif,
|
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&f->fw_out_if, f->fw_flg & IP_FW_F_OIFNAME)))
|
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continue;
|
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}
|
|
|
|
/* Check IP options */
|
|
if (f->fw_ipopt != f->fw_ipnopt && !ipopts_match(ip, f))
|
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continue;
|
|
|
|
/* Check protocol; if wildcard, match */
|
|
if (f->fw_prot == IPPROTO_IP)
|
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goto got_match;
|
|
|
|
/* If different, don't match */
|
|
if (ip->ip_p != f->fw_prot)
|
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continue;
|
|
|
|
#define PULLUP_TO(len) do { \
|
|
if ((*m)->m_len < (len) \
|
|
&& (*m = m_pullup(*m, (len))) == 0) { \
|
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goto bogusfrag; \
|
|
} \
|
|
*pip = ip = mtod(*m, struct ip *); \
|
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offset = (ip->ip_off & IP_OFFMASK); \
|
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} 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_uar.fw_pts[0],
|
|
IP_FW_GETNSRCP(f), src_port,
|
|
f->fw_flg & IP_FW_F_SRNG))
|
|
continue;
|
|
if (!port_match(&f->fw_uar.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:
|
|
/* Update statistics */
|
|
f->fw_pcnt += 1;
|
|
f->fw_bcnt += ip->ip_len;
|
|
f->timestamp = time_second;
|
|
|
|
/* Log to console if desired */
|
|
if ((f->fw_flg & IP_FW_F_PRN) && fw_verbose)
|
|
ipfw_report(f, ip, 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:
|
|
*cookie = f->fw_number;
|
|
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 (LIST_NEXT(chain, chain)
|
|
&& LIST_NEXT(chain, chain)->rule->fw_number
|
|
< f->fw_skipto_rule)
|
|
#else
|
|
while (LIST_NEXT(chain, chain)->rule->fw_number
|
|
< f->fw_skipto_rule)
|
|
#endif
|
|
chain = LIST_NEXT(chain, chain);
|
|
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, 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_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.
|
|
*/
|
|
*cookie = 0;
|
|
if (*m) {
|
|
m_freem(*m);
|
|
*m = NULL;
|
|
}
|
|
return(0);
|
|
}
|
|
|
|
static int
|
|
add_entry(struct ip_fw_head *chainptr, struct ip_fw *frwl)
|
|
{
|
|
struct ip_fw *ftmp = 0;
|
|
struct ip_fw_chain *fwc = 0, *fcp, *fcpl = 0;
|
|
u_short nbr = 0;
|
|
int s;
|
|
|
|
fwc = malloc(sizeof *fwc, M_IPFW, M_DONTWAIT);
|
|
ftmp = malloc(sizeof *ftmp, M_IPFW, M_DONTWAIT);
|
|
if (!fwc || !ftmp) {
|
|
dprintf(("%s malloc said no\n", err_prefix));
|
|
if (fwc) free(fwc, M_IPFW);
|
|
if (ftmp) free(ftmp, M_IPFW);
|
|
return (ENOSPC);
|
|
}
|
|
|
|
bcopy(frwl, ftmp, sizeof(struct ip_fw));
|
|
ftmp->fw_in_if.fu_via_if.name[FW_IFNLEN - 1] = '\0';
|
|
ftmp->fw_pcnt = 0L;
|
|
ftmp->fw_bcnt = 0L;
|
|
fwc->rule = ftmp;
|
|
|
|
s = splnet();
|
|
|
|
if (!LIST_FIRST(chainptr)) {
|
|
LIST_INSERT_HEAD(chainptr, fwc, chain);
|
|
splx(s);
|
|
return(0);
|
|
} else if (ftmp->fw_number == (u_short)-1) {
|
|
if (fwc) free(fwc, M_IPFW);
|
|
if (ftmp) free(ftmp, M_IPFW);
|
|
splx(s);
|
|
dprintf(("%s bad rule number\n", err_prefix));
|
|
return (EINVAL);
|
|
}
|
|
|
|
/* If entry number is 0, find highest numbered rule and add 100 */
|
|
if (ftmp->fw_number == 0) {
|
|
for (fcp = LIST_FIRST(chainptr); fcp; fcp = LIST_NEXT(fcp, chain)) {
|
|
if (fcp->rule->fw_number != (u_short)-1)
|
|
nbr = fcp->rule->fw_number;
|
|
else
|
|
break;
|
|
}
|
|
if (nbr < (u_short)-1 - 100)
|
|
nbr += 100;
|
|
ftmp->fw_number = nbr;
|
|
}
|
|
|
|
/* Got a valid number; now insert it, keeping the list ordered */
|
|
for (fcp = LIST_FIRST(chainptr); fcp; fcp = LIST_NEXT(fcp, chain)) {
|
|
if (fcp->rule->fw_number > ftmp->fw_number) {
|
|
if (fcpl) {
|
|
LIST_INSERT_AFTER(fcpl, fwc, chain);
|
|
} else {
|
|
LIST_INSERT_HEAD(chainptr, fwc, chain);
|
|
}
|
|
break;
|
|
} else {
|
|
fcpl = fcp;
|
|
}
|
|
}
|
|
|
|
splx(s);
|
|
return (0);
|
|
}
|
|
|
|
static int
|
|
del_entry(struct ip_fw_head *chainptr, u_short number)
|
|
{
|
|
struct ip_fw_chain *fcp;
|
|
|
|
fcp = LIST_FIRST(chainptr);
|
|
if (number != (u_short)-1) {
|
|
for (; fcp; fcp = LIST_NEXT(fcp, chain)) {
|
|
if (fcp->rule->fw_number == number) {
|
|
int s;
|
|
|
|
/* prevent access to rules while removing them */
|
|
s = splnet();
|
|
while (fcp && fcp->rule->fw_number == number) {
|
|
struct ip_fw_chain *next;
|
|
|
|
next = LIST_NEXT(fcp, chain);
|
|
LIST_REMOVE(fcp, chain);
|
|
free(fcp->rule, M_IPFW);
|
|
free(fcp, M_IPFW);
|
|
fcp = next;
|
|
}
|
|
splx(s);
|
|
return 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
return (EINVAL);
|
|
}
|
|
|
|
static int
|
|
zero_entry(struct mbuf *m)
|
|
{
|
|
struct ip_fw *frwl;
|
|
struct ip_fw_chain *fcp;
|
|
int s;
|
|
|
|
if (m) {
|
|
if (m->m_len != sizeof(struct ip_fw))
|
|
return(EINVAL);
|
|
frwl = mtod(m, struct ip_fw *);
|
|
}
|
|
else
|
|
frwl = NULL;
|
|
|
|
if (!frwl) {
|
|
s = splnet();
|
|
for (fcp = LIST_FIRST(&ip_fw_chain); fcp; fcp = LIST_NEXT(fcp, chain)) {
|
|
fcp->rule->fw_bcnt = fcp->rule->fw_pcnt = 0;
|
|
fcp->rule->timestamp = 0;
|
|
}
|
|
splx(s);
|
|
}
|
|
else {
|
|
int cleared = 0;
|
|
|
|
/*
|
|
* It's possible to insert multiple chain entries with the
|
|
* same number, so we don't stop after finding the first
|
|
* match if zeroing a specific entry.
|
|
*/
|
|
for (fcp = LIST_FIRST(&ip_fw_chain); fcp; fcp = LIST_NEXT(fcp, chain))
|
|
if (frwl->fw_number == fcp->rule->fw_number) {
|
|
s = splnet();
|
|
while (fcp && frwl->fw_number == fcp->rule->fw_number) {
|
|
fcp->rule->fw_bcnt = fcp->rule->fw_pcnt = 0;
|
|
fcp->rule->timestamp = 0;
|
|
fcp = LIST_NEXT(fcp, chain);
|
|
}
|
|
splx(s);
|
|
cleared = 1;
|
|
break;
|
|
}
|
|
if (!cleared)
|
|
return(EINVAL); /* we didn't find any matching rules */
|
|
}
|
|
|
|
if (fw_verbose) {
|
|
if (frwl)
|
|
printf("ipfw: Entry %d cleared.\n", frwl->fw_number);
|
|
else
|
|
printf("ipfw: Accounting cleared.\n");
|
|
}
|
|
|
|
return(0);
|
|
}
|
|
|
|
static struct ip_fw *
|
|
check_ipfw_mbuf(struct mbuf *m)
|
|
{
|
|
/* Check length */
|
|
if (m->m_len != sizeof(struct ip_fw)) {
|
|
dprintf(("%s len=%d, want %d\n", err_prefix, m->m_len,
|
|
sizeof(struct ip_fw)));
|
|
return (NULL);
|
|
}
|
|
return(check_ipfw_struct(mtod(m, struct ip_fw *)));
|
|
}
|
|
|
|
static struct ip_fw *
|
|
check_ipfw_struct(struct ip_fw *frwl)
|
|
{
|
|
/* Check for invalid flag bits */
|
|
if ((frwl->fw_flg & ~IP_FW_F_MASK) != 0) {
|
|
dprintf(("%s undefined flag bits set (flags=%x)\n",
|
|
err_prefix, frwl->fw_flg));
|
|
return (NULL);
|
|
}
|
|
/* Must apply to incoming or outgoing (or both) */
|
|
if (!(frwl->fw_flg & (IP_FW_F_IN | IP_FW_F_OUT))) {
|
|
dprintf(("%s neither in nor out\n", err_prefix));
|
|
return (NULL);
|
|
}
|
|
/* Empty interface name is no good */
|
|
if (((frwl->fw_flg & IP_FW_F_IIFNAME)
|
|
&& !*frwl->fw_in_if.fu_via_if.name)
|
|
|| ((frwl->fw_flg & IP_FW_F_OIFNAME)
|
|
&& !*frwl->fw_out_if.fu_via_if.name)) {
|
|
dprintf(("%s empty interface name\n", err_prefix));
|
|
return (NULL);
|
|
}
|
|
/* Sanity check interface matching */
|
|
if ((frwl->fw_flg & IF_FW_F_VIAHACK) == IF_FW_F_VIAHACK) {
|
|
; /* allow "via" backwards compatibility */
|
|
} else if ((frwl->fw_flg & IP_FW_F_IN)
|
|
&& (frwl->fw_flg & IP_FW_F_OIFACE)) {
|
|
dprintf(("%s outgoing interface check on incoming\n",
|
|
err_prefix));
|
|
return (NULL);
|
|
}
|
|
/* Sanity check port ranges */
|
|
if ((frwl->fw_flg & IP_FW_F_SRNG) && IP_FW_GETNSRCP(frwl) < 2) {
|
|
dprintf(("%s src range set but n_src_p=%d\n",
|
|
err_prefix, IP_FW_GETNSRCP(frwl)));
|
|
return (NULL);
|
|
}
|
|
if ((frwl->fw_flg & IP_FW_F_DRNG) && IP_FW_GETNDSTP(frwl) < 2) {
|
|
dprintf(("%s dst range set but n_dst_p=%d\n",
|
|
err_prefix, IP_FW_GETNDSTP(frwl)));
|
|
return (NULL);
|
|
}
|
|
if (IP_FW_GETNSRCP(frwl) + IP_FW_GETNDSTP(frwl) > IP_FW_MAX_PORTS) {
|
|
dprintf(("%s too many ports (%d+%d)\n",
|
|
err_prefix, IP_FW_GETNSRCP(frwl), IP_FW_GETNDSTP(frwl)));
|
|
return (NULL);
|
|
}
|
|
/*
|
|
* Protocols other than TCP/UDP don't use port range
|
|
*/
|
|
if ((frwl->fw_prot != IPPROTO_TCP) &&
|
|
(frwl->fw_prot != IPPROTO_UDP) &&
|
|
(IP_FW_GETNSRCP(frwl) || IP_FW_GETNDSTP(frwl))) {
|
|
dprintf(("%s port(s) specified for non TCP/UDP rule\n",
|
|
err_prefix));
|
|
return(NULL);
|
|
}
|
|
|
|
/*
|
|
* Rather than modify the entry to make such entries work,
|
|
* we reject this rule and require user level utilities
|
|
* to enforce whatever policy they deem appropriate.
|
|
*/
|
|
if ((frwl->fw_src.s_addr & (~frwl->fw_smsk.s_addr)) ||
|
|
(frwl->fw_dst.s_addr & (~frwl->fw_dmsk.s_addr))) {
|
|
dprintf(("%s rule never matches\n", err_prefix));
|
|
return(NULL);
|
|
}
|
|
|
|
if ((frwl->fw_flg & IP_FW_F_FRAG) &&
|
|
(frwl->fw_prot == IPPROTO_UDP || frwl->fw_prot == IPPROTO_TCP)) {
|
|
if (frwl->fw_nports) {
|
|
dprintf(("%s cannot mix 'frag' and ports\n", err_prefix));
|
|
return(NULL);
|
|
}
|
|
if (frwl->fw_prot == IPPROTO_TCP &&
|
|
frwl->fw_tcpf != frwl->fw_tcpnf) {
|
|
dprintf(("%s cannot mix 'frag' and TCP flags\n", err_prefix));
|
|
return(NULL);
|
|
}
|
|
}
|
|
|
|
/* Check command specific stuff */
|
|
switch (frwl->fw_flg & IP_FW_F_COMMAND)
|
|
{
|
|
case IP_FW_F_REJECT:
|
|
if (frwl->fw_reject_code >= 0x100
|
|
&& !(frwl->fw_prot == IPPROTO_TCP
|
|
&& frwl->fw_reject_code == IP_FW_REJECT_RST)) {
|
|
dprintf(("%s unknown reject code\n", err_prefix));
|
|
return(NULL);
|
|
}
|
|
break;
|
|
case IP_FW_F_DIVERT: /* Diverting to port zero is invalid */
|
|
case IP_FW_F_TEE:
|
|
if (frwl->fw_divert_port == 0) {
|
|
dprintf(("%s can't divert to port 0\n", err_prefix));
|
|
return (NULL);
|
|
}
|
|
break;
|
|
case IP_FW_F_DENY:
|
|
case IP_FW_F_ACCEPT:
|
|
case IP_FW_F_COUNT:
|
|
case IP_FW_F_SKIPTO:
|
|
break;
|
|
default:
|
|
dprintf(("%s invalid command\n", err_prefix));
|
|
return(NULL);
|
|
}
|
|
|
|
return frwl;
|
|
}
|
|
|
|
static int
|
|
ip_fw_ctl(int stage, struct mbuf **mm)
|
|
{
|
|
int error;
|
|
/*
|
|
* If we have any number of rules, then it's worth while
|
|
* using clusters for this. The smaller case is rare.
|
|
* Note that using clusters for setsockopt is only in 3.0 at this time.
|
|
*/
|
|
struct mbuf *m;
|
|
|
|
if (stage == IP_FW_GET) {
|
|
/*
|
|
* If we have any number of rules, then it's worth while
|
|
* using clusters for this. The smaller case is rare.
|
|
* Note that using clusters for setsockopt is only in
|
|
* 3.0 at this time.
|
|
*/
|
|
struct ip_fw_chain *fcp = LIST_FIRST(&ip_fw_chain);
|
|
*mm = m = m_get(M_WAIT, MT_SOOPTS);
|
|
if (m == NULL)
|
|
return (ENOBUFS);
|
|
MCLGET(m, M_WAIT);
|
|
if(!(m->m_flags & M_EXT)) {
|
|
abort: m_freem(*mm);
|
|
*mm = NULL;
|
|
return (ENOBUFS);
|
|
}
|
|
m->m_len = 0;
|
|
for (; fcp; fcp = LIST_NEXT(fcp, chain)) {
|
|
/* Will we need a new cluster? */
|
|
if((m->m_len + sizeof *(fcp->rule)) > MCLBYTES) {
|
|
m = m->m_next = m_get(M_WAIT, MT_SOOPTS);
|
|
if (m == NULL) {
|
|
goto abort;
|
|
}
|
|
MCLGET(m, M_WAIT);
|
|
if (!(m->m_flags & M_EXT)) {
|
|
goto abort;
|
|
}
|
|
m->m_len = 0;
|
|
}
|
|
memcpy(m->m_data + m->m_len, fcp->rule,
|
|
sizeof *(fcp->rule));
|
|
m->m_len += sizeof *(fcp->rule);
|
|
}
|
|
return (0);
|
|
}
|
|
m = *mm;
|
|
/* only allow get calls if secure mode > 2 */
|
|
if (securelevel > 2) {
|
|
if (m) (void)m_free(m);
|
|
return(EPERM);
|
|
}
|
|
if (stage == IP_FW_FLUSH) {
|
|
while (LIST_FIRST(&ip_fw_chain) != NULL &&
|
|
LIST_FIRST(&ip_fw_chain)->rule->fw_number != (u_short)-1) {
|
|
struct ip_fw_chain *fcp = LIST_FIRST(&ip_fw_chain);
|
|
int s = splnet();
|
|
LIST_REMOVE(LIST_FIRST(&ip_fw_chain), chain);
|
|
splx(s);
|
|
free(fcp->rule, M_IPFW);
|
|
free(fcp, M_IPFW);
|
|
}
|
|
if (m) (void)m_free(m);
|
|
return (0);
|
|
}
|
|
if (stage == IP_FW_ZERO) {
|
|
error = zero_entry(m);
|
|
if (m) (void)m_free(m);
|
|
return (error);
|
|
}
|
|
if (m == NULL) {
|
|
printf("%s NULL mbuf ptr\n", err_prefix);
|
|
return (EINVAL);
|
|
}
|
|
|
|
if (stage == IP_FW_ADD) {
|
|
struct ip_fw *frwl = check_ipfw_mbuf(m);
|
|
|
|
if (!frwl)
|
|
error = EINVAL;
|
|
else
|
|
error = add_entry(&ip_fw_chain, frwl);
|
|
if (m) (void)m_free(m);
|
|
return error;
|
|
}
|
|
if (stage == IP_FW_DEL) {
|
|
if (m->m_len != sizeof(struct ip_fw)) {
|
|
dprintf(("%s len=%d, want %d\n", err_prefix, m->m_len,
|
|
sizeof(struct ip_fw)));
|
|
error = EINVAL;
|
|
} else if (mtod(m, struct ip_fw *)->fw_number == (u_short)-1) {
|
|
dprintf(("%s can't delete rule 65535\n", err_prefix));
|
|
error = EINVAL;
|
|
} else
|
|
error = del_entry(&ip_fw_chain,
|
|
mtod(m, struct ip_fw *)->fw_number);
|
|
if (m) (void)m_free(m);
|
|
return error;
|
|
}
|
|
|
|
dprintf(("%s unknown request %d\n", err_prefix, stage));
|
|
if (m) (void)m_free(m);
|
|
return (EINVAL);
|
|
}
|
|
|
|
void
|
|
ip_fw_init(void)
|
|
{
|
|
struct ip_fw default_rule;
|
|
|
|
ip_fw_chk_ptr = ip_fw_chk;
|
|
ip_fw_ctl_ptr = ip_fw_ctl;
|
|
LIST_INIT(&ip_fw_chain);
|
|
|
|
bzero(&default_rule, sizeof default_rule);
|
|
default_rule.fw_prot = IPPROTO_IP;
|
|
default_rule.fw_number = (u_short)-1;
|
|
#ifdef IPFIREWALL_DEFAULT_TO_ACCEPT
|
|
default_rule.fw_flg |= IP_FW_F_ACCEPT;
|
|
#else
|
|
default_rule.fw_flg |= IP_FW_F_DENY;
|
|
#endif
|
|
default_rule.fw_flg |= IP_FW_F_IN | IP_FW_F_OUT;
|
|
if (check_ipfw_struct(&default_rule) == NULL ||
|
|
add_entry(&ip_fw_chain, &default_rule))
|
|
panic("ip_fw_init");
|
|
|
|
printf("IP packet filtering initialized, "
|
|
#ifdef IPDIVERT
|
|
"divert enabled, ");
|
|
#else
|
|
"divert disabled, ");
|
|
#endif
|
|
#ifdef IPFIREWALL_DEFAULT_TO_ACCEPT
|
|
printf("default to accept, ");
|
|
#endif
|
|
#ifndef IPFIREWALL_VERBOSE
|
|
printf("logging disabled\n");
|
|
#else
|
|
if (fw_verbose_limit == 0)
|
|
printf("unlimited logging\n");
|
|
else
|
|
printf("logging limited to %d packets/entry\n",
|
|
fw_verbose_limit);
|
|
#endif
|
|
}
|
|
|
|
#ifdef IPFIREWALL_MODULE
|
|
|
|
#include <sys/exec.h>
|
|
#include <sys/sysent.h>
|
|
#include <sys/lkm.h>
|
|
|
|
MOD_MISC(ipfw);
|
|
|
|
static int
|
|
ipfw_load(struct lkm_table *lkmtp, int cmd)
|
|
{
|
|
int s=splnet();
|
|
|
|
old_chk_ptr = ip_fw_chk_ptr;
|
|
old_ctl_ptr = ip_fw_ctl_ptr;
|
|
|
|
ip_fw_init();
|
|
splx(s);
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
ipfw_unload(struct lkm_table *lkmtp, int cmd)
|
|
{
|
|
int s=splnet();
|
|
|
|
ip_fw_chk_ptr = old_chk_ptr;
|
|
ip_fw_ctl_ptr = old_ctl_ptr;
|
|
|
|
while (LIST_FIRST(&ip_fw_chain) != NULL) {
|
|
struct ip_fw_chain *fcp = LIST_FIRST(&ip_fw_chain);
|
|
LIST_REMOVE(LIST_FIRST(&ip_fw_chain), chain);
|
|
free(fcp->rule, M_IPFW);
|
|
free(fcp, M_IPFW);
|
|
}
|
|
|
|
splx(s);
|
|
printf("IP firewall unloaded\n");
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
ipfw_mod(struct lkm_table *lkmtp, int cmd, int ver)
|
|
{
|
|
MOD_DISPATCH(ipfw, lkmtp, cmd, ver,
|
|
ipfw_load, ipfw_unload, lkm_nullcmd);
|
|
}
|
|
#endif
|