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 33 /* Operations - f_srcop, f_dstop */ 34 #define OP_NONE 0 35 #define OP_EQ 1 36 #define OP_GT 2 37 #define OP_LT 3 38 39 /* srctype or dsttype */ 40 #define T_ADDR 0 41 #define T_MYADDR 1 42 #define T_HISADDR 2 43 44 /* 45 * There's a struct filterent for each possible filter rule. The 46 * layout is designed to minimise size (there are 4 * MAXFILTERS of 47 * them) - which is also conveniently a power of 2 (32 bytes) on 48 * architectures where sizeof(int)==4 (this makes indexing faster). 49 * 50 * f_action and f_proto only need to be 6 and 3 bits, respectively, 51 * but making them 8 bits allows them to be efficently accessed using 52 * byte operations as well as allowing space for future expansion 53 * (expanding MAXFILTERS or converting f_proto IPPROTO_... values). 54 * 55 * Note that there are four free bits in the initial word for future 56 * extensions. 57 */ 58 struct filterent { 59 unsigned f_action : 8; /* Filtering action: goto or A_... */ 60 unsigned f_proto : 8; /* Protocol: P_... */ 61 unsigned f_srcop : 2; /* Source port operation: OP_... */ 62 unsigned f_dstop : 2; /* Destination port operation: OP_... */ 63 unsigned f_srctype : 2; /* T_ value of src */ 64 unsigned f_dsttype : 2; /* T_ value of dst */ 65 unsigned f_estab : 1; /* Check TCP ACK bit */ 66 unsigned f_syn : 1; /* Check TCP SYN bit */ 67 unsigned f_finrst : 1; /* Check TCP FIN/RST bits */ 68 unsigned f_invert : 1; /* true to complement match */ 69 struct in_range f_src; /* Source address and mask */ 70 struct in_range f_dst; /* Destination address and mask */ 71 u_short f_srcport; /* Source port, compared with f_srcop */ 72 u_short f_dstport; /* Destination port, compared with f_dstop */ 73 }; 74 75 #define MAXFILTERS 40 /* in each filter set */ 76 77 /* f_action values [0..MAXFILTERS) specify the next filter rule, others are: */ 78 #define A_NONE (MAXFILTERS) 79 #define A_PERMIT (A_NONE+1) 80 #define A_DENY (A_PERMIT+1) 81 82 struct filter { 83 struct filterent rule[MAXFILTERS]; /* incoming packet filter */ 84 const char *name; 85 unsigned fragok : 1; 86 unsigned logok : 1; 87 }; 88 89 /* Which filter set */ 90 #define FL_IN 0 91 #define FL_OUT 1 92 #define FL_DIAL 2 93 #define FL_KEEP 3 94 95 struct ipcp; 96 struct cmdargs; 97 98 extern int ParseAddr(struct ipcp *, const char *, struct in_addr *, 99 struct in_addr *, int *); 100 extern int filter_Show(struct cmdargs const *); 101 extern int filter_Set(struct cmdargs const *); 102 extern const char * filter_Action2Nam(int); 103 extern const char *filter_Proto2Nam(int); 104 extern const char *filter_Op2Nam(int); 105 extern struct in_addr bits2mask(int); 106 extern void filter_AdjustAddr(struct filter *, struct in_addr *, 107 struct in_addr *); 108