/* * IP firewalling code. This is taken from 4.4BSD. Please note the * copyright message below. As per the GPL it must be maintained * and the licenses thus do not conflict. While this port is subject * to the GPL I also place my modifications under the original * license in recognition of the original copyright. * * Ported from BSD to Linux, * Alan Cox 22/Nov/1994. * Merged and included the FreeBSD-Current changes at Ugen's request * (but hey it's a lot cleaner now). Ugen would prefer in some ways * we waited for his final product but since Linux 1.2.0 is about to * appear it's not practical - Read: It works, it's not clean but please * don't consider it to be his standard of finished work. * Alan. * * Fixes: * Pauline Middelink : Added masquerading. * Jos Vos : Separate input and output firewall * chains, new "insert" and "append" * commands to replace "add" commands, * add ICMP header to struct ip_fwpkt. * Jos Vos : Add support for matching device names. * Willy Konynenberg : Add transparent proxying support. * Jos Vos : Add options for input/output accounting. * * All the real work was done by ..... */ /* * Copyright (c) 1993 Daniel Boulet * Copyright (c) 1994 Ugen J.S.Antsilevich * * Redistribution and use in source forms, with and without modification, * are permitted provided that this entire comment appears intact. * * Redistribution in binary form may occur without any restrictions. * Obviously, it would be nice if you gave credit where credit is due * but requiring it would be too onerous. * * This software is provided ``AS IS'' without any warranties of any kind. */ /* * Format of an IP firewall descriptor * * src, dst, src_mask, dst_mask are always stored in network byte order. * flags and num_*_ports are stored in host byte order (of course). * Port numbers are stored in HOST byte order. */ #ifndef _IP_FW_H #define _IP_FW_H #include #include #include #include #include struct ip_fw { struct ip_fw *fw_next; /* Next firewall on chain */ struct in_addr fw_src, fw_dst; /* Source and destination IP addr */ struct in_addr fw_smsk, fw_dmsk; /* Mask for src and dest IP addr */ struct in_addr fw_via; /* IP address of interface "via" */ struct device *fw_viadev; /* device of interface "via" */ __u16 fw_flg; /* Flags word */ __u16 fw_nsp, fw_ndp; /* N'of src ports and # of dst ports */ /* in ports array (dst ports follow */ /* src ports; max of 10 ports in all; */ /* count of 0 means match all ports) */ #define IP_FW_MAX_PORTS 10 /* A reasonable maximum */ __u16 fw_pts[IP_FW_MAX_PORTS]; /* Array of port numbers to match */ unsigned long fw_pcnt,fw_bcnt; /* Packet and byte counters */ __u8 fw_tosand, fw_tosxor; /* Revised packet priority */ char fw_vianame[IFNAMSIZ]; /* name of interface "via" */ }; /* * Values for "flags" field . */ #define IP_FW_F_ALL 0x0000 /* This is a universal packet firewall*/ #define IP_FW_F_TCP 0x0001 /* This is a TCP packet firewall */ #define IP_FW_F_UDP 0x0002 /* This is a UDP packet firewall */ #define IP_FW_F_ICMP 0x0003 /* This is a ICMP packet firewall */ #define IP_FW_F_KIND 0x0003 /* Mask to isolate firewall kind */ #define IP_FW_F_ACCEPT 0x0004 /* This is an accept firewall (as * * opposed to a deny firewall)* * */ #define IP_FW_F_SRNG 0x0008 /* The first two src ports are a min * * and max range (stored in host byte * * order). * * */ #define IP_FW_F_DRNG 0x0010 /* The first two dst ports are a min * * and max range (stored in host byte * * order). * * (ports[0] <= port <= ports[1]) * * */ #define IP_FW_F_PRN 0x0020 /* In verbose mode print this firewall*/ #define IP_FW_F_BIDIR 0x0040 /* For bidirectional firewalls */ #define IP_FW_F_TCPSYN 0x0080 /* For tcp packets-check SYN only */ #define IP_FW_F_ICMPRPL 0x0100 /* Send back icmp unreachable packet */ #define IP_FW_F_MASQ 0x0200 /* Masquerading */ #define IP_FW_F_TCPACK 0x0400 /* For tcp-packets match if ACK is set*/ #define IP_FW_F_REDIR 0x0800 /* Redirect to local port fw_pts[n] */ #define IP_FW_F_ACCTIN 0x1000 /* Account incoming packets only. */ #define IP_FW_F_ACCTOUT 0x2000 /* Account outgoing packets only. */ #define IP_FW_F_MASK 0x3FFF /* All possible flag bits mask */ /* * New IP firewall options for [gs]etsockopt at the RAW IP level. * Unlike BSD Linux inherits IP options so you don't have to use * a raw socket for this. Instead we check rights in the calls. */ #define IP_FW_BASE_CTL 64 /* base for firewall socket options */ #define IP_FW_COMMAND 0x00FF /* mask for command without chain */ #define IP_FW_TYPE 0x0300 /* mask for type (chain) */ #define IP_FW_SHIFT 8 /* shift count for type (chain) */ #define IP_FW_FWD 0 #define IP_FW_IN 1 #define IP_FW_OUT 2 #define IP_FW_ACCT 3 #define IP_FW_CHAINS 4 /* total number of ip_fw chains */ #define IP_FW_INSERT (IP_FW_BASE_CTL) #define IP_FW_APPEND (IP_FW_BASE_CTL+1) #define IP_FW_DELETE (IP_FW_BASE_CTL+2) #define IP_FW_FLUSH (IP_FW_BASE_CTL+3) #define IP_FW_ZERO (IP_FW_BASE_CTL+4) #define IP_FW_POLICY (IP_FW_BASE_CTL+5) #define IP_FW_CHECK (IP_FW_BASE_CTL+6) #define IP_FW_MASQ_TIMEOUTS (IP_FW_BASE_CTL+7) #define IP_FW_INSERT_FWD (IP_FW_INSERT | (IP_FW_FWD << IP_FW_SHIFT)) #define IP_FW_APPEND_FWD (IP_FW_APPEND | (IP_FW_FWD << IP_FW_SHIFT)) #define IP_FW_DELETE_FWD (IP_FW_DELETE | (IP_FW_FWD << IP_FW_SHIFT)) #define IP_FW_FLUSH_FWD (IP_FW_FLUSH | (IP_FW_FWD << IP_FW_SHIFT)) #define IP_FW_ZERO_FWD (IP_FW_ZERO | (IP_FW_FWD << IP_FW_SHIFT)) #define IP_FW_POLICY_FWD (IP_FW_POLICY | (IP_FW_FWD << IP_FW_SHIFT)) #define IP_FW_CHECK_FWD (IP_FW_CHECK | (IP_FW_FWD << IP_FW_SHIFT)) #define IP_FW_INSERT_IN (IP_FW_INSERT | (IP_FW_IN << IP_FW_SHIFT)) #define IP_FW_APPEND_IN (IP_FW_APPEND | (IP_FW_IN << IP_FW_SHIFT)) #define IP_FW_DELETE_IN (IP_FW_DELETE | (IP_FW_IN << IP_FW_SHIFT)) #define IP_FW_FLUSH_IN (IP_FW_FLUSH | (IP_FW_IN << IP_FW_SHIFT)) #define IP_FW_ZERO_IN (IP_FW_ZERO | (IP_FW_IN << IP_FW_SHIFT)) #define IP_FW_POLICY_IN (IP_FW_POLICY | (IP_FW_IN << IP_FW_SHIFT)) #define IP_FW_CHECK_IN (IP_FW_CHECK | (IP_FW_IN << IP_FW_SHIFT)) #define IP_FW_INSERT_OUT (IP_FW_INSERT | (IP_FW_OUT << IP_FW_SHIFT)) #define IP_FW_APPEND_OUT (IP_FW_APPEND | (IP_FW_OUT << IP_FW_SHIFT)) #define IP_FW_DELETE_OUT (IP_FW_DELETE | (IP_FW_OUT << IP_FW_SHIFT)) #define IP_FW_FLUSH_OUT (IP_FW_FLUSH | (IP_FW_OUT << IP_FW_SHIFT)) #define IP_FW_ZERO_OUT (IP_FW_ZERO | (IP_FW_OUT << IP_FW_SHIFT)) #define IP_FW_POLICY_OUT (IP_FW_POLICY | (IP_FW_OUT << IP_FW_SHIFT)) #define IP_FW_CHECK_OUT (IP_FW_CHECK | (IP_FW_OUT << IP_FW_SHIFT)) #define IP_ACCT_INSERT (IP_FW_INSERT | (IP_FW_ACCT << IP_FW_SHIFT)) #define IP_ACCT_APPEND (IP_FW_APPEND | (IP_FW_ACCT << IP_FW_SHIFT)) #define IP_ACCT_DELETE (IP_FW_DELETE | (IP_FW_ACCT << IP_FW_SHIFT)) #define IP_ACCT_FLUSH (IP_FW_FLUSH | (IP_FW_ACCT << IP_FW_SHIFT)) #define IP_ACCT_ZERO (IP_FW_ZERO | (IP_FW_ACCT << IP_FW_SHIFT)) struct ip_fwpkt { struct iphdr fwp_iph; /* IP header */ union { struct tcphdr fwp_tcph; /* TCP header or */ struct udphdr fwp_udph; /* UDP header */ struct icmphdr fwp_icmph; /* ICMP header */ } fwp_protoh; struct in_addr fwp_via; /* interface address */ char fwp_vianame[IFNAMSIZ]; /* interface name */ }; /* * timeouts for ip masquerading */ struct ip_fw_masq; /* * Main firewall chains definitions and global var's definitions. */ #ifdef __KERNEL__ /* Modes used in the ip_fw_chk() routine. */ #define IP_FW_MODE_FW 0x00 /* kernel firewall check */ #define IP_FW_MODE_ACCT_IN 0x01 /* accounting (incoming) */ #define IP_FW_MODE_ACCT_OUT 0x02 /* accounting (outgoing) */ #define IP_FW_MODE_CHK 0x04 /* check requested by user */ #include #ifdef CONFIG_IP_FIREWALL extern struct ip_fw *ip_fw_in_chain; extern struct ip_fw *ip_fw_out_chain; extern struct ip_fw *ip_fw_fwd_chain; extern int ip_fw_in_policy; extern int ip_fw_out_policy; extern int ip_fw_fwd_policy; extern int ip_fw_ctl(int, void *, int); #endif #ifdef CONFIG_IP_ACCT extern struct ip_fw *ip_acct_chain; extern int ip_acct_ctl(int, void *, int); #endif extern int ip_fw_chk(struct iphdr *, struct device *, __u16 *, struct ip_fw *, int, int); extern void ip_fw_init(void); #endif /* KERNEL */ #endif /* _IP_FW_H */