113 lines
3.7 KiB
C
113 lines
3.7 KiB
C
/*
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* Written by Toshiharu OHNO (tony-o@iij.ad.jp)
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*
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* Copyright (C) 1993, Internet Initiative Japan, Inc. All rights reserverd.
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*
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* Redistribution and use in source and binary forms are permitted
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* provided that the above copyright notice and this paragraph are
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* duplicated in all such forms and that any documentation,
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* advertising materials, and other materials related to such
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* distribution and use acknowledge that the software was developed
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* by the Internet Initiative Japan. The name of the
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* IIJ may not be used to endorse or promote products derived
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* from this software without specific prior written permission.
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
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* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*
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* $FreeBSD$
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*
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* TODO:
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*/
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/* Known protocols - f_proto */
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#define P_NONE 0
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#define P_TCP 1
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#define P_UDP 2
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#define P_ICMP 3
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#ifdef IPPROTO_OSPFIGP
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#define P_OSPF 4
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#endif
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#define P_IGMP 5
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#ifdef IPPROTO_GRE
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#define P_GRE 6
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#endif
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/* Operations - f_srcop, f_dstop */
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#define OP_NONE 0
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#define OP_EQ 1
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#define OP_GT 2
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#define OP_LT 3
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/* srctype or dsttype */
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#define T_ADDR 0
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#define T_MYADDR 1
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#define T_HISADDR 2
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#define T_DNS0 3
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#define T_DNS1 4
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/*
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* There's a struct filterent for each possible filter rule. The
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* layout is designed to minimise size (there are 4 * MAXFILTERS of
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* them) - which is also conveniently a power of 2 (32 bytes) on
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* architectures where sizeof(int)==4 (this makes indexing faster).
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*
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* f_action and f_proto only need to be 6 and 3 bits, respectively,
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* but making them 8 bits allows them to be efficently accessed using
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* byte operations as well as allowing space for future expansion
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* (expanding MAXFILTERS or converting f_proto IPPROTO_... values).
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*
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* Note that there are four free bits in the initial word for future
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* extensions.
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*/
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struct filterent {
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unsigned f_action : 8; /* Filtering action: goto or A_... */
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unsigned f_proto : 8; /* Protocol: P_... */
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unsigned f_srcop : 2; /* Source port operation: OP_... */
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unsigned f_dstop : 2; /* Destination port operation: OP_... */
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unsigned f_srctype : 3; /* T_ value of src */
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unsigned f_dsttype : 3; /* T_ value of dst */
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unsigned f_estab : 1; /* Check TCP ACK bit */
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unsigned f_syn : 1; /* Check TCP SYN bit */
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unsigned f_finrst : 1; /* Check TCP FIN/RST bits */
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unsigned f_invert : 1; /* true to complement match */
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struct in_range f_src; /* Source address and mask */
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struct in_range f_dst; /* Destination address and mask */
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u_short f_srcport; /* Source port, compared with f_srcop */
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u_short f_dstport; /* Destination port, compared with f_dstop */
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};
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#define MAXFILTERS 40 /* in each filter set */
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/* f_action values [0..MAXFILTERS) specify the next filter rule, others are: */
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#define A_NONE (MAXFILTERS)
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#define A_PERMIT (A_NONE+1)
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#define A_DENY (A_PERMIT+1)
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struct filter {
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struct filterent rule[MAXFILTERS]; /* incoming packet filter */
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const char *name;
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unsigned fragok : 1;
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unsigned logok : 1;
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};
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/* Which filter set */
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#define FL_IN 0
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#define FL_OUT 1
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#define FL_DIAL 2
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#define FL_KEEP 3
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struct ipcp;
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struct cmdargs;
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extern int ParseAddr(struct ipcp *, const char *, struct in_addr *,
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struct in_addr *, int *);
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extern int filter_Show(struct cmdargs const *);
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extern int filter_Set(struct cmdargs const *);
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extern const char * filter_Action2Nam(int);
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extern const char *filter_Proto2Nam(int);
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extern const char *filter_Op2Nam(int);
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extern struct in_addr bits2mask(int);
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extern void filter_AdjustAddr(struct filter *, struct in_addr *,
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struct in_addr *, struct in_addr [2]);
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