0
0
mirror of https://gitlab.nic.cz/labs/bird.git synced 2024-12-23 10:11:53 +00:00
bird/filter/filter.h
Jan Maria Matejka e8bc64e308 Filter: make bgpmask literals real constructors
The bgpmask literals can include expressions. This is OK but they have
to be interpreted as soon as the code is run, not in the time the code
is used as value.

This led to strange behavior like rewriting bgpmasks when they shan't
be rewritten:

	function mask_generator(int as)
	{
		return [= * as * =];
	}

	function another()
	bgpmask m1;
	bgpmask m2;
	{
		m1 = mask_generator(10);
		m2 = mask_generator(20);
		if (m1 == m2) {
			print("strange"); # this would happen
		}
	}

Moreover, sending this to CLI would cause stack overflow and knock down the
whole BIRD, as soon as there is at least one route to execute the given
filter on.

	show route filter bgpmask mmm; bgppath ppp; { ppp = +empty+; mmm = [= (ppp ~ mmm) =]; print(mmm); accept; }

The magic match operator (~) inside the bgpmask literal would try to
resolve mmm, which points to the same bgpmask so it would resolve
itself, call the magic match operator and vice versa.

After this patch, the bgpmask literal will get resolved as soon as it's
assigned to mmm and it also will return a type error as bool is not
convertible to ASN in BIRD.
2018-03-14 11:34:29 +01:00

307 lines
7.7 KiB
C

/*
* BIRD Internet Routing Daemon -- Filters
*
* (c) 1999 Pavel Machek <pavel@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#ifndef _BIRD_FILT_H_
#define _BIRD_FILT_H_
#include "lib/resource.h"
#include "lib/ip.h"
#include "nest/route.h"
#include "nest/attrs.h"
/* Filter instruction types */
#define FI__TWOCHAR(a,b) ((a<<8) | b)
#define FI__LIST \
F(FI_ADD, 0, '+') \
F(FI_SUBTRACT, 0, '-') \
F(FI_MULTIPLY, 0, '*') \
F(FI_DIVIDE, 0, '/') \
F(FI_AND, 0, '&') \
F(FI_OR, 0, '|') \
F(FI_PAIR_CONSTRUCT, 'm', 'p') \
F(FI_EC_CONSTRUCT, 'm', 'c') \
F(FI_LC_CONSTRUCT, 'm', 'l') \
F(FI_PATHMASK_CONSTRUCT, 'm', 'P') \
F(FI_NEQ, '!', '=') \
F(FI_EQ, '=', '=') \
F(FI_LT, 0, '<') \
F(FI_LTE, '<', '=') \
F(FI_NOT, 0, '!') \
F(FI_MATCH, 0, '~') \
F(FI_NOT_MATCH, '!', '~') \
F(FI_DEFINED, 'd', 'e') \
F(FI_SET, 0, 's') \
F(FI_CONSTANT, 0, 'c') \
F(FI_VARIABLE, 0, 'V') \
F(FI_CONSTANT_INDIRECT, 0, 'C') \
F(FI_PRINT, 0, 'p') \
F(FI_CONDITION, 0, '?') \
F(FI_NOP, 0, '0') \
F(FI_PRINT_AND_DIE, 'p', ',') \
F(FI_RTA_GET, 0, 'a') \
F(FI_RTA_SET, 'a', 'S') \
F(FI_EA_GET, 'e', 'a') \
F(FI_EA_SET, 'e', 'S') \
F(FI_PREF_GET, 0, 'P') \
F(FI_PREF_SET, 'P', 'S') \
F(FI_LENGTH, 0, 'L') \
F(FI_IP, 'c', 'p') \
F(FI_AS_PATH_FIRST, 'a', 'f') \
F(FI_AS_PATH_LAST, 'a', 'l') \
F(FI_AS_PATH_LAST_NAG, 'a', 'L') \
F(FI_RETURN, 0, 'r') \
F(FI_CALL, 'c', 'a') \
F(FI_CLEAR_LOCAL_VARS, 'c', 'V') \
F(FI_SWITCH, 'S', 'W') \
F(FI_IP_MASK, 'i', 'M') \
F(FI_EMPTY, 0, 'E') \
F(FI_PATH_PREPEND, 'A', 'p') \
F(FI_CLIST_ADD_DEL, 'C', 'a') \
F(FI_ROA_CHECK, 'R', 'C')
enum f_instruction_code {
#define F(c,a,b) \
c = FI__TWOCHAR(a,b),
FI__LIST
#undef F
} PACKED;
struct f_inst { /* Instruction */
struct f_inst *next; /* Structure is 16 bytes, anyway */
enum f_instruction_code fi_code;
u16 aux;
union {
int i;
void *p;
} a1;
union {
int i;
void *p;
} a2;
int lineno;
};
#define arg1 a1.p
#define arg2 a2.p
/* Not enough fields in f_inst for three args used by roa_check() */
struct f_inst_roa_check {
struct f_inst i;
struct roa_table_config *rtc;
};
struct f_inst3 {
struct f_inst i;
union {
int i;
void *p;
} a3;
};
#define INST3(x) (((struct f_inst3 *) x)->a3)
struct f_prefix {
ip_addr ip;
int len;
#define LEN_MASK 0xff
#define LEN_PLUS 0x1000000
#define LEN_MINUS 0x2000000
#define LEN_RANGE 0x4000000
/* If range then prefix must be in range (len >> 16 & 0xff, len >> 8 & 0xff) */
};
struct f_val {
int type;
union {
uint i;
u64 ec;
lcomm lc;
/* ip_addr ip; Folded into prefix */
struct f_prefix px;
char *s;
struct f_tree *t;
struct f_trie *ti;
struct adata *ad;
struct f_path_mask *path_mask;
} val;
};
struct f_dynamic_attr {
int type;
int f_type;
int ea_code;
};
struct f_static_attr {
int f_type;
int sa_code;
int readonly;
};
struct filter {
char *name;
struct f_inst *root;
};
struct f_inst *f_new_inst(enum f_instruction_code fi_code);
struct f_inst *f_new_inst_da(enum f_instruction_code fi_code, struct f_dynamic_attr da);
struct f_inst *f_new_inst_sa(enum f_instruction_code fi_code, struct f_static_attr sa);
static inline struct f_dynamic_attr f_new_dynamic_attr(int type, int f_type, int code) /* Type as core knows it, type as filters know it, and code of dynamic attribute */
{ return (struct f_dynamic_attr) { .type = type, .f_type = f_type, .ea_code = code }; } /* f_type currently unused; will be handy for static type checking */
static inline struct f_static_attr f_new_static_attr(int f_type, int code, int readonly)
{ return (struct f_static_attr) { .f_type = f_type, .sa_code = code, .readonly = readonly }; }
struct f_tree *f_new_tree(void);
struct f_inst *f_generate_complex(int operation, int operation_aux, struct f_dynamic_attr da, struct f_inst *argument);
struct f_inst *f_generate_roa_check(struct symbol *sym, struct f_inst *prefix, struct f_inst *asn);
struct f_tree *build_tree(struct f_tree *);
struct f_tree *find_tree(struct f_tree *t, struct f_val val);
int same_tree(struct f_tree *t1, struct f_tree *t2);
void tree_format(struct f_tree *t, buffer *buf);
struct f_trie *f_new_trie(linpool *lp, uint node_size);
void *trie_add_prefix(struct f_trie *t, ip_addr px, int plen, int l, int h);
int trie_match_prefix(struct f_trie *t, ip_addr px, int plen);
int trie_same(struct f_trie *t1, struct f_trie *t2);
void trie_format(struct f_trie *t, buffer *buf);
void fprefix_get_bounds(struct f_prefix *px, int *l, int *h);
static inline void
trie_add_fprefix(struct f_trie *t, struct f_prefix *px)
{
int l, h;
fprefix_get_bounds(px, &l, &h);
trie_add_prefix(t, px->ip, px->len & LEN_MASK, l, h);
}
static inline int
trie_match_fprefix(struct f_trie *t, struct f_prefix *px)
{
return trie_match_prefix(t, px->ip, px->len & LEN_MASK);
}
struct ea_list;
struct rte;
int f_run(struct filter *filter, struct rte **rte, struct ea_list **tmp_attrs, struct linpool *tmp_pool, int flags);
struct f_val f_eval_rte(struct f_inst *expr, struct rte **rte, struct linpool *tmp_pool);
struct f_val f_eval(struct f_inst *expr, struct linpool *tmp_pool);
uint f_eval_int(struct f_inst *expr);
char *filter_name(struct filter *filter);
int filter_same(struct filter *new, struct filter *old);
int i_same(struct f_inst *f1, struct f_inst *f2);
int val_compare(struct f_val v1, struct f_val v2);
int val_same(struct f_val v1, struct f_val v2);
void val_format(struct f_val v, buffer *buf);
#define F_NOP 0
#define F_NONL 1
#define F_ACCEPT 2 /* Need to preserve ordering: accepts < rejects! */
#define F_REJECT 3
#define F_ERROR 4
#define F_QUITBIRD 5
#define FILTER_ACCEPT NULL
#define FILTER_REJECT ((void *) 1)
/* Type numbers must be in 0..0xff range */
#define T_MASK 0xff
/* Internal types */
/* Do not use type of zero, that way we'll see errors easier. */
#define T_VOID 1
/* User visible types, which fit in int */
#define T_INT 0x10
#define T_BOOL 0x11
#define T_PAIR 0x12 /* Notice that pair is stored as integer: first << 16 | second */
#define T_QUAD 0x13
/* Put enumerational types in 0x30..0x3f range */
#define T_ENUM_LO 0x30
#define T_ENUM_HI 0x3f
#define T_ENUM_RTS 0x30
#define T_ENUM_BGP_ORIGIN 0x31
#define T_ENUM_SCOPE 0x32
#define T_ENUM_RTC 0x33
#define T_ENUM_RTD 0x34
#define T_ENUM_ROA 0x35
#define T_ENUM_RA_PREFERENCE 0x36
/* new enums go here */
#define T_ENUM_EMPTY 0x3f /* Special hack for atomic_aggr */
#define T_ENUM T_ENUM_LO ... T_ENUM_HI
/* Bigger ones */
#define T_IP 0x20
#define T_PREFIX 0x21
#define T_STRING 0x22
#define T_PATH_MASK 0x23 /* mask for BGP path */
#define T_PATH 0x24 /* BGP path */
#define T_CLIST 0x25 /* Community list */
#define T_EC 0x26 /* Extended community value, u64 */
#define T_ECLIST 0x27 /* Extended community list */
#define T_LC 0x28 /* Large community value, lcomm */
#define T_LCLIST 0x29 /* Large community list */
#define T_RETURN 0x40
#define T_SET 0x80
#define T_PREFIX_SET 0x81
#define SA_FROM 1
#define SA_GW 2
#define SA_NET 3
#define SA_PROTO 4
#define SA_SOURCE 5
#define SA_SCOPE 6
#define SA_CAST 7
#define SA_DEST 8
#define SA_IFNAME 9
#define SA_IFINDEX 10
struct f_tree {
struct f_tree *left, *right;
struct f_val from, to;
void *data;
};
struct f_trie_node
{
ip_addr addr, mask, accept;
int plen;
struct f_trie_node *c[2];
};
struct f_trie
{
linpool *lp;
int zero;
uint node_size;
struct f_trie_node root[0]; /* Root trie node follows */
};
#define NEW_F_VAL struct f_val * val; val = cfg_alloc(sizeof(struct f_val));
#define FF_FORCE_TMPATTR 1 /* Force all attributes to be temporary */
#define FF_SILENT 2 /* Silent filter execution */
#endif