1 /* 2 * Written by Toshiharu OHNO (tony-o@iij.ad.jp) 3 * 4 * Copyright (C) 1993, Internet Initiative Japan, Inc. All rights reserverd. 5 * 6 * Redistribution and use in source and binary forms are permitted 7 * provided that the above copyright notice and this paragraph are 8 * duplicated in all such forms and that any documentation, 9 * advertising materials, and other materials related to such 10 * distribution and use acknowledge that the software was developed 11 * by the Internet Initiative Japan. The name of the 12 * IIJ may not be used to endorse or promote products derived 13 * from this software without specific prior written permission. 14 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 15 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 16 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. 17 * 18 * $FreeBSD$ 19 * 20 * TODO: 21 */ 22 23 /* Known protocols - f_proto */ 24 #define P_NONE 0 25 #define P_TCP 1 26 #define P_UDP 2 27 #define P_ICMP 3 28 #ifdef IPPROTO_OSPFIGP 29 #define P_OSPF 4 30 #endif 31 #define P_IGMP 5 32 #ifdef IPPROTO_GRE 33 #define P_GRE 6 34 #endif 35 36 /* Operations - f_srcop, f_dstop */ 37 #define OP_NONE 0 38 #define OP_EQ 1 39 #define OP_GT 2 40 #define OP_LT 3 41 42 /* srctype or dsttype */ 43 #define T_ADDR 0 44 #define T_MYADDR 1 45 #define T_HISADDR 2 46 47 /* 48 * There's a struct filterent for each possible filter rule. The 49 * layout is designed to minimise size (there are 4 * MAXFILTERS of 50 * them) - which is also conveniently a power of 2 (32 bytes) on 51 * architectures where sizeof(int)==4 (this makes indexing faster). 52 * 53 * f_action and f_proto only need to be 6 and 3 bits, respectively, 54 * but making them 8 bits allows them to be efficently accessed using 55 * byte operations as well as allowing space for future expansion 56 * (expanding MAXFILTERS or converting f_proto IPPROTO_... values). 57 * 58 * Note that there are four free bits in the initial word for future 59 * extensions. 60 */ 61 struct filterent { 62 unsigned f_action : 8; /* Filtering action: goto or A_... */ 63 unsigned f_proto : 8; /* Protocol: P_... */ 64 unsigned f_srcop : 2; /* Source port operation: OP_... */ 65 unsigned f_dstop : 2; /* Destination port operation: OP_... */ 66 unsigned f_srctype : 2; /* T_ value of src */ 67 unsigned f_dsttype : 2; /* T_ value of dst */ 68 unsigned f_estab : 1; /* Check TCP ACK bit */ 69 unsigned f_syn : 1; /* Check TCP SYN bit */ 70 unsigned f_finrst : 1; /* Check TCP FIN/RST bits */ 71 unsigned f_invert : 1; /* true to complement match */ 72 struct in_range f_src; /* Source address and mask */ 73 struct in_range f_dst; /* Destination address and mask */ 74 u_short f_srcport; /* Source port, compared with f_srcop */ 75 u_short f_dstport; /* Destination port, compared with f_dstop */ 76 }; 77 78 #define MAXFILTERS 40 /* in each filter set */ 79 80 /* f_action values [0..MAXFILTERS) specify the next filter rule, others are: */ 81 #define A_NONE (MAXFILTERS) 82 #define A_PERMIT (A_NONE+1) 83 #define A_DENY (A_PERMIT+1) 84 85 struct filter { 86 struct filterent rule[MAXFILTERS]; /* incoming packet filter */ 87 const char *name; 88 unsigned fragok : 1; 89 unsigned logok : 1; 90 }; 91 92 /* Which filter set */ 93 #define FL_IN 0 94 #define FL_OUT 1 95 #define FL_DIAL 2 96 #define FL_KEEP 3 97 98 struct ipcp; 99 struct cmdargs; 100 101 extern int ParseAddr(struct ipcp *, const char *, struct in_addr *, 102 struct in_addr *, int *); 103 extern int filter_Show(struct cmdargs const *); 104 extern int filter_Set(struct cmdargs const *); 105 extern const char * filter_Action2Nam(int); 106 extern const char *filter_Proto2Nam(int); 107 extern const char *filter_Op2Nam(int); 108 extern struct in_addr bits2mask(int); 109 extern void filter_AdjustAddr(struct filter *, struct in_addr *, 110 struct in_addr *); 111