/* * 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. * * 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 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" */ unsigned short fw_flg; /* Flags word */ unsigned short 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 */ unsigned short fw_pts[IP_FW_MAX_PORTS]; /* Array of port numbers to match */ unsigned long fw_pcnt,fw_bcnt; /* Packet and byte counters */ }; /* * Values for "flags" field . */ #define IP_FW_F_ALL 0x000 /* This is a universal packet firewall*/ #define IP_FW_F_TCP 0x001 /* This is a TCP packet firewall */ #define IP_FW_F_UDP 0x002 /* This is a UDP packet firewall */ #define IP_FW_F_ICMP 0x003 /* This is a ICMP packet firewall */ #define IP_FW_F_KIND 0x003 /* Mask to isolate firewall kind */ #define IP_FW_F_ACCEPT 0x004 /* This is an accept firewall (as * * opposed to a deny firewall)* * */ #define IP_FW_F_SRNG 0x008 /* The first two src ports are a min * * and max range (stored in host byte * * order). * * */ #define IP_FW_F_DRNG 0x010 /* 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 0x020 /* In verbose mode print this firewall*/ #define IP_FW_F_BIDIR 0x040 /* For bidirectional firewalls */ #define IP_FW_F_TCPSYN 0x080 /* For tcp packets-check SYN only */ #define IP_FW_F_ICMPRPL 0x100 /* Send back icmp unreachable packet */ #define IP_FW_F_MASQ 0x200 /* Masquerading */ #define IP_FW_F_MASK 0x3FF /* 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 #define IP_FW_ADD_BLK (IP_FW_BASE_CTL) #define IP_FW_ADD_FWD (IP_FW_BASE_CTL+1) #define IP_FW_CHK_BLK (IP_FW_BASE_CTL+2) #define IP_FW_CHK_FWD (IP_FW_BASE_CTL+3) #define IP_FW_DEL_BLK (IP_FW_BASE_CTL+4) #define IP_FW_DEL_FWD (IP_FW_BASE_CTL+5) #define IP_FW_FLUSH_BLK (IP_FW_BASE_CTL+6) #define IP_FW_FLUSH_FWD (IP_FW_BASE_CTL+7) #define IP_FW_ZERO_BLK (IP_FW_BASE_CTL+8) #define IP_FW_ZERO_FWD (IP_FW_BASE_CTL+9) #define IP_FW_POLICY_BLK (IP_FW_BASE_CTL+10) #define IP_FW_POLICY_FWD (IP_FW_BASE_CTL+11) #define IP_ACCT_ADD (IP_FW_BASE_CTL+16) #define IP_ACCT_DEL (IP_FW_BASE_CTL+17) #define IP_ACCT_FLUSH (IP_FW_BASE_CTL+18) #define IP_ACCT_ZERO (IP_FW_BASE_CTL+19) struct ip_fwpkt { struct iphdr fwp_iph; /* IP header */ union { struct tcphdr fwp_tcph; /* TCP header or */ struct udphdr fwp_udph; /* UDP header */ } fwp_protoh; struct in_addr fwp_via; /* interface address */ }; /* * Main firewall chains definitions and global var's definitions. */ #ifdef __KERNEL__ #include #ifdef CONFIG_IP_MASQUERADE struct ip_masq { struct ip_masq *next; /* next member in list */ struct timer_list timer; /* Expiration timer */ __u16 protocol; /* Which protocol are we talking? */ __u32 src, dst; /* Source and destination IP addresses */ __u16 sport,dport; /* Source and destoination ports */ __u16 mport; /* Masquaraded port */ __u32 init_seq; /* Add delta from this seq. on */ short delta; /* Delta in sequence numbers */ char sawfin; /* Did we saw an FIN packet? */ }; extern struct ip_masq *ip_msq_hosts; extern void ip_fw_masquerade(struct sk_buff **, struct device *); extern int ip_fw_demasquerade(struct sk_buff *); #endif #ifdef CONFIG_IP_FIREWALL extern struct ip_fw *ip_fw_blk_chain; extern struct ip_fw *ip_fw_fwd_chain; extern int ip_fw_blk_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 void ip_acct_cnt(struct iphdr *, struct device *, struct ip_fw *); extern int ip_acct_ctl(int, void *, int); #endif extern int ip_fw_chk(struct iphdr *, struct device *rif,struct ip_fw *, int, int); #endif /* KERNEL */ #ifdef CONFIG_IP_MASQUERADE #undef DEBUG_MASQ #define MASQUERADE_EXPIRE_TCP 15*60*HZ #define MASQUERADE_EXPIRE_TCP_FIN 2*60*HZ #define MASQUERADE_EXPIRE_UDP 5*60*HZ /* * Linux ports don't normally get allocated above 32K. I used an extra 4K port-space */ #define PORT_MASQ_BEGIN 60000 #define PORT_MASQ_END (PORT_MASQ_BEGIN+4096) #endif #endif /* _IP_FW_H */