/* * Format of an ARP firewall descriptor * * src, tgt, src_mask, tgt_mask, arpop, arpop_mask are always stored in * network byte order. * flags are stored in host byte order (of course). */ #ifndef _ARPTABLES_H #define _ARPTABLES_H #ifdef __KERNEL__ #include #include #include #include #include #endif #include #define ARPT_FUNCTION_MAXNAMELEN 30 #define ARPT_TABLE_MAXNAMELEN 32 #define ARPT_DEV_ADDR_LEN_MAX 16 struct arpt_devaddr_info { char addr[ARPT_DEV_ADDR_LEN_MAX]; char mask[ARPT_DEV_ADDR_LEN_MAX]; }; /* Yes, Virginia, you have to zero the padding. */ struct arpt_arp { /* Source and target IP addr */ struct in_addr src, tgt; /* Mask for src and target IP addr */ struct in_addr smsk, tmsk; /* Device hw address length, src+target device addresses */ u_int8_t arhln, arhln_mask; struct arpt_devaddr_info src_devaddr; struct arpt_devaddr_info tgt_devaddr; /* ARP operation code. */ u_int16_t arpop, arpop_mask; /* ARP hardware address and protocol address format. */ u_int16_t arhrd, arhrd_mask; u_int16_t arpro, arpro_mask; /* The protocol address length is only accepted if it is 4 * so there is no use in offering a way to do filtering on it. */ char iniface[IFNAMSIZ], outiface[IFNAMSIZ]; unsigned char iniface_mask[IFNAMSIZ], outiface_mask[IFNAMSIZ]; /* Flags word */ u_int8_t flags; /* Inverse flags */ u_int16_t invflags; }; struct arpt_entry_target { union { struct { u_int16_t target_size; /* Used by userspace */ char name[ARPT_FUNCTION_MAXNAMELEN]; } user; struct { u_int16_t target_size; /* Used inside the kernel */ struct arpt_target *target; } kernel; /* Total length */ u_int16_t target_size; } u; unsigned char data[0]; }; struct arpt_standard_target { struct arpt_entry_target target; int verdict; }; struct arpt_counters { u_int64_t pcnt, bcnt; /* Packet and byte counters */ }; /* Values for "flag" field in struct arpt_ip (general arp structure). * No flags defined yet. */ #define ARPT_F_MASK 0x00 /* All possible flag bits mask. */ /* Values for "inv" field in struct arpt_arp. */ #define ARPT_INV_VIA_IN 0x0001 /* Invert the sense of IN IFACE. */ #define ARPT_INV_VIA_OUT 0x0002 /* Invert the sense of OUT IFACE */ #define ARPT_INV_SRCIP 0x0004 /* Invert the sense of SRC IP. */ #define ARPT_INV_TGTIP 0x0008 /* Invert the sense of TGT IP. */ #define ARPT_INV_SRCDEVADDR 0x0010 /* Invert the sense of SRC DEV ADDR. */ #define ARPT_INV_TGTDEVADDR 0x0020 /* Invert the sense of TGT DEV ADDR. */ #define ARPT_INV_ARPOP 0x0040 /* Invert the sense of ARP OP. */ #define ARPT_INV_ARPHRD 0x0080 /* Invert the sense of ARP HRD. */ #define ARPT_INV_ARPPRO 0x0100 /* Invert the sense of ARP PRO. */ #define ARPT_INV_ARPHLN 0x0200 /* Invert the sense of ARP HLN. */ #define ARPT_INV_MASK 0x03FF /* All possible flag bits mask. */ /* This structure defines each of the firewall rules. Consists of 3 parts which are 1) general ARP header stuff 2) match specific stuff 3) the target to perform if the rule matches */ struct arpt_entry { struct arpt_arp arp; /* Size of arpt_entry + matches */ u_int16_t target_offset; /* Size of arpt_entry + matches + target */ u_int16_t next_offset; /* Back pointer */ unsigned int comefrom; /* Packet and byte counters. */ struct arpt_counters counters; /* The matches (if any), then the target. */ unsigned char elems[0]; }; /* * 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 ARPT_BASE_CTL 96 /* base for firewall socket options */ #define ARPT_SO_SET_REPLACE (ARPT_BASE_CTL) #define ARPT_SO_SET_ADD_COUNTERS (ARPT_BASE_CTL + 1) #define ARPT_SO_SET_MAX ARPT_SO_SET_ADD_COUNTERS #define ARPT_SO_GET_INFO (ARPT_BASE_CTL) #define ARPT_SO_GET_ENTRIES (ARPT_BASE_CTL + 1) #define ARPT_SO_GET_MAX ARPT_SO_GET_ENTRIES /* CONTINUE verdict for targets */ #define ARPT_CONTINUE 0xFFFFFFFF /* For standard target */ #define ARPT_RETURN (-NF_MAX_VERDICT - 1) /* The argument to ARPT_SO_GET_INFO */ struct arpt_getinfo { /* Which table: caller fills this in. */ char name[ARPT_TABLE_MAXNAMELEN]; /* Kernel fills these in. */ /* Which hook entry points are valid: bitmask */ unsigned int valid_hooks; /* Hook entry points: one per netfilter hook. */ unsigned int hook_entry[3]; /* Underflow points. */ unsigned int underflow[3]; /* Number of entries */ unsigned int num_entries; /* Size of entries. */ unsigned int size; }; /* The argument to ARPT_SO_SET_REPLACE. */ struct arpt_replace { /* Which table. */ char name[ARPT_TABLE_MAXNAMELEN]; /* Which hook entry points are valid: bitmask. You can't change this. */ unsigned int valid_hooks; /* Number of entries */ unsigned int num_entries; /* Total size of new entries */ unsigned int size; /* Hook entry points. */ unsigned int hook_entry[3]; /* Underflow points. */ unsigned int underflow[3]; /* Information about old entries: */ /* Number of counters (must be equal to current number of entries). */ unsigned int num_counters; /* The old entries' counters. */ struct arpt_counters *counters; /* The entries (hang off end: not really an array). */ struct arpt_entry entries[0]; }; /* The argument to ARPT_SO_ADD_COUNTERS. */ struct arpt_counters_info { /* Which table. */ char name[ARPT_TABLE_MAXNAMELEN]; unsigned int num_counters; /* The counters (actually `number' of these). */ struct arpt_counters counters[0]; }; /* The argument to ARPT_SO_GET_ENTRIES. */ struct arpt_get_entries { /* Which table: user fills this in. */ char name[ARPT_TABLE_MAXNAMELEN]; /* User fills this in: total entry size. */ unsigned int size; /* The entries. */ struct arpt_entry entrytable[0]; }; /* Standard return verdict, or do jump. */ #define ARPT_STANDARD_TARGET "" /* Error verdict. */ #define ARPT_ERROR_TARGET "ERROR" /* Helper functions */ static __inline__ struct arpt_entry_target *arpt_get_target(struct arpt_entry *e) { return (void *)e + e->target_offset; } /* fn returns 0 to continue iteration */ #define ARPT_ENTRY_ITERATE(entries, size, fn, args...) \ ({ \ unsigned int __i; \ int __ret = 0; \ struct arpt_entry *__entry; \ \ for (__i = 0; __i < (size); __i += __entry->next_offset) { \ __entry = (void *)(entries) + __i; \ \ __ret = fn(__entry , ## args); \ if (__ret != 0) \ break; \ } \ __ret; \ }) /* * Main firewall chains definitions and global var's definitions. */ #ifdef __KERNEL__ /* Registration hooks for targets. */ struct arpt_target { struct list_head list; const char name[ARPT_FUNCTION_MAXNAMELEN]; /* Returns verdict. */ unsigned int (*target)(struct sk_buff **pskb, unsigned int hooknum, const struct net_device *in, const struct net_device *out, const void *targinfo, void *userdata); /* Called when user tries to insert an entry of this type: hook_mask is a bitmask of hooks from which it can be called. */ /* Should return true or false. */ int (*checkentry)(const char *tablename, const struct arpt_entry *e, void *targinfo, unsigned int targinfosize, unsigned int hook_mask); /* Called when entry of this type deleted. */ void (*destroy)(void *targinfo, unsigned int targinfosize); /* Set this to THIS_MODULE if you are a module, otherwise NULL */ struct module *me; }; extern int arpt_register_target(struct arpt_target *target); extern void arpt_unregister_target(struct arpt_target *target); /* Furniture shopping... */ struct arpt_table { struct list_head list; /* A unique name... */ char name[ARPT_TABLE_MAXNAMELEN]; /* Seed table: copied in register_table */ struct arpt_replace *table; /* What hooks you will enter on */ unsigned int valid_hooks; /* Lock for the curtain */ rwlock_t lock; /* Man behind the curtain... */ struct arpt_table_info *private; /* Set this to THIS_MODULE if you are a module, otherwise NULL */ struct module *me; }; extern int arpt_register_table(struct arpt_table *table); extern void arpt_unregister_table(struct arpt_table *table); extern unsigned int arpt_do_table(struct sk_buff **pskb, unsigned int hook, const struct net_device *in, const struct net_device *out, struct arpt_table *table, void *userdata); #define ARPT_ALIGN(s) (((s) + (__alignof__(struct arpt_entry)-1)) & ~(__alignof__(struct arpt_entry)-1)) #endif /*__KERNEL__*/ #endif /* _ARPTABLES_H */