bird/filter/filter.c

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/*
* Filters: utility functions
*
* Copyright 1998 Pavel Machek <pavel@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*
*/
/**
* DOC: Filters
*
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* You can find sources of the filter language in |filter/|
* directory. File |filter/config.Y| contains filter grammar and basically translates
* the source from user into a tree of &f_inst structures. These trees are
* later interpreted using code in |filter/filter.c|.
*
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* A filter is represented by a tree of &f_inst structures, one structure per
* "instruction". Each &f_inst contains @code, @aux value which is
* usually the data type this instruction operates on and two generic
* arguments (@a1, @a2). Some instructions contain pointer(s) to other
* instructions in their (@a1, @a2) fields.
*
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* Filters use a &f_val structure for their data. Each &f_val
* contains type and value (types are constants prefixed with %T_). Few
* of the types are special; %T_RETURN can be or-ed with a type to indicate
* that return from a function or from the whole filter should be
* forced. Important thing about &f_val's is that they may be copied
* with a simple |=|. That's fine for all currently defined types: strings
* are read-only (and therefore okay), paths are copied for each
* operation (okay too).
*/
#undef LOCAL_DEBUG
#include "nest/bird.h"
#include "lib/lists.h"
#include "lib/resource.h"
#include "lib/socket.h"
#include "lib/string.h"
#include "lib/unaligned.h"
#include "lib/net.h"
#include "lib/ip.h"
#include "nest/route.h"
#include "nest/protocol.h"
#include "nest/iface.h"
#include "nest/attrs.h"
#include "conf/conf.h"
#include "filter/filter.h"
#define CMP_ERROR 999
#define FILTER_STACK_DEPTH 16384
/* Filter interpreter stack. Make this thread local after going parallel. */
struct filter_stack {
struct f_val val;
};
static struct filter_stack filter_stack[FILTER_STACK_DEPTH];
/* Internal filter state, to be allocated on stack when executing filters */
struct filter_state {
struct rte **rte;
struct rta *old_rta;
struct ea_list **eattrs;
struct linpool *pool;
struct buffer buf;
struct filter_stack *stack;
int stack_ptr;
int flags;
};
void (*bt_assert_hook)(int result, struct f_inst *assert);
static struct adata undef_adata; /* adata of length 0 used for undefined */
/* Special undef value for paths and clists */
static inline int
undef_value(struct f_val v)
{
return ((v.type == T_PATH) || (v.type == T_CLIST) ||
(v.type == T_ECLIST) || (v.type == T_LCLIST)) &&
(v.val.ad == &undef_adata);
}
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static struct adata *
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adata_empty(struct linpool *pool, int l)
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{
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struct adata *res = lp_alloc(pool, sizeof(struct adata) + l);
res->length = l;
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return res;
}
static void
pm_format(struct f_path_mask *p, buffer *buf)
{
buffer_puts(buf, "[= ");
while (p)
{
switch(p->kind)
{
case PM_ASN:
buffer_print(buf, "%u ", p->val);
break;
case PM_QUESTION:
buffer_puts(buf, "? ");
break;
case PM_ASTERISK:
buffer_puts(buf, "* ");
break;
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case PM_ASN_RANGE:
buffer_print(buf, "%u..%u ", p->val, p->val2);
break;
case PM_ASN_EXPR:
ASSERT(0);
}
p = p->next;
}
buffer_puts(buf, "=]");
}
static inline int val_is_ip4(const struct f_val v)
{ return (v.type == T_IP) && ipa_is_ip4(v.val.ip); }
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static inline int
lcomm_cmp(lcomm v1, lcomm v2)
{
if (v1.asn != v2.asn)
return (v1.asn > v2.asn) ? 1 : -1;
if (v1.ldp1 != v2.ldp1)
return (v1.ldp1 > v2.ldp1) ? 1 : -1;
if (v1.ldp2 != v2.ldp2)
return (v1.ldp2 > v2.ldp2) ? 1 : -1;
return 0;
}
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/**
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* val_compare - compare two values
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* @v1: first value
* @v2: second value
*
* Compares two values and returns -1, 0, 1 on <, =, > or CMP_ERROR on
* error. Tree module relies on this giving consistent results so
* that it can be used for building balanced trees.
*/
int
val_compare(struct f_val v1, struct f_val v2)
{
if (v1.type != v2.type) {
if (v1.type == T_VOID) /* Hack for else */
return -1;
if (v2.type == T_VOID)
return 1;
/* IP->Quad implicit conversion */
if ((v1.type == T_QUAD) && val_is_ip4(v2))
return uint_cmp(v1.val.i, ipa_to_u32(v2.val.ip));
if (val_is_ip4(v1) && (v2.type == T_QUAD))
return uint_cmp(ipa_to_u32(v1.val.ip), v2.val.i);
debug( "Types do not match in val_compare\n" );
return CMP_ERROR;
}
switch (v1.type) {
case T_VOID:
return 0;
case T_ENUM:
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case T_INT:
case T_BOOL:
case T_PAIR:
case T_QUAD:
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return uint_cmp(v1.val.i, v2.val.i);
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case T_EC:
case T_RD:
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return u64_cmp(v1.val.ec, v2.val.ec);
case T_LC:
return lcomm_cmp(v1.val.lc, v2.val.lc);
case T_IP:
return ipa_compare(v1.val.ip, v2.val.ip);
case T_NET:
return net_compare(v1.val.net, v2.val.net);
case T_STRING:
return strcmp(v1.val.s, v2.val.s);
default:
return CMP_ERROR;
}
}
static int
pm_same(struct f_path_mask *m1, struct f_path_mask *m2)
{
while (m1 && m2)
{
if (m1->kind != m2->kind)
return 0;
if (m1->kind == PM_ASN_EXPR)
{
if (!i_same((struct f_inst *) m1->val, (struct f_inst *) m2->val))
return 0;
}
else
{
if ((m1->val != m2->val) || (m1->val2 != m2->val2))
return 0;
}
m1 = m1->next;
m2 = m2->next;
}
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return !m1 && !m2;
}
/**
* val_same - compare two values
* @v1: first value
* @v2: second value
*
* Compares two values and returns 1 if they are same and 0 if not.
* Comparison of values of different types is valid and returns 0.
*/
int
val_same(struct f_val v1, struct f_val v2)
{
int rc;
rc = val_compare(v1, v2);
if (rc != CMP_ERROR)
return !rc;
if (v1.type != v2.type)
return 0;
switch (v1.type) {
case T_PATH_MASK:
return pm_same(v1.val.path_mask, v2.val.path_mask);
case T_PATH:
case T_CLIST:
case T_ECLIST:
case T_LCLIST:
return adata_same(v1.val.ad, v2.val.ad);
case T_SET:
return same_tree(v1.val.t, v2.val.t);
case T_PREFIX_SET:
return trie_same(v1.val.ti, v2.val.ti);
default:
bug("Invalid type in val_same(): %x", v1.type);
}
}
static int
clist_set_type(struct f_tree *set, struct f_val *v)
{
switch (set->from.type)
{
case T_PAIR:
v->type = T_PAIR;
return 1;
case T_QUAD:
v->type = T_QUAD;
return 1;
case T_IP:
if (val_is_ip4(set->from) && val_is_ip4(set->to))
{
v->type = T_QUAD;
return 1;
}
/* Fall through */
default:
v->type = T_VOID;
return 0;
}
}
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static inline int
eclist_set_type(struct f_tree *set)
{ return set->from.type == T_EC; }
static inline int
lclist_set_type(struct f_tree *set)
{ return set->from.type == T_LC; }
static int
clist_match_set(struct adata *clist, struct f_tree *set)
{
if (!clist)
return 0;
struct f_val v;
if (!clist_set_type(set, &v))
return CMP_ERROR;
u32 *l = (u32 *) clist->data;
u32 *end = l + clist->length/4;
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while (l < end) {
v.val.i = *l++;
if (find_tree(set, v))
return 1;
}
return 0;
}
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static int
eclist_match_set(struct adata *list, struct f_tree *set)
{
if (!list)
return 0;
if (!eclist_set_type(set))
return CMP_ERROR;
struct f_val v;
u32 *l = int_set_get_data(list);
int len = int_set_get_size(list);
int i;
v.type = T_EC;
for (i = 0; i < len; i += 2) {
v.val.ec = ec_get(l, i);
if (find_tree(set, v))
return 1;
}
return 0;
}
static int
lclist_match_set(struct adata *list, struct f_tree *set)
{
if (!list)
return 0;
if (!lclist_set_type(set))
return CMP_ERROR;
struct f_val v;
u32 *l = int_set_get_data(list);
int len = int_set_get_size(list);
int i;
v.type = T_LC;
for (i = 0; i < len; i += 3) {
v.val.lc = lc_get(l, i);
if (find_tree(set, v))
return 1;
}
return 0;
}
static struct adata *
clist_filter(struct linpool *pool, struct adata *list, struct f_val set, int pos)
{
if (!list)
return NULL;
int tree = (set.type == T_SET); /* 1 -> set is T_SET, 0 -> set is T_CLIST */
struct f_val v;
if (tree)
clist_set_type(set.val.t, &v);
else
v.type = T_PAIR;
int len = int_set_get_size(list);
u32 *l = int_set_get_data(list);
u32 tmp[len];
u32 *k = tmp;
u32 *end = l + len;
while (l < end) {
v.val.i = *l++;
/* pos && member(val, set) || !pos && !member(val, set), member() depends on tree */
if ((tree ? !!find_tree(set.val.t, v) : int_set_contains(set.val.ad, v.val.i)) == pos)
*k++ = v.val.i;
}
uint nl = (k - tmp) * sizeof(u32);
if (nl == list->length)
return list;
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struct adata *res = adata_empty(pool, nl);
memcpy(res->data, tmp, nl);
return res;
}
static struct adata *
eclist_filter(struct linpool *pool, struct adata *list, struct f_val set, int pos)
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{
if (!list)
return NULL;
int tree = (set.type == T_SET); /* 1 -> set is T_SET, 0 -> set is T_CLIST */
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struct f_val v;
int len = int_set_get_size(list);
u32 *l = int_set_get_data(list);
u32 tmp[len];
u32 *k = tmp;
int i;
v.type = T_EC;
for (i = 0; i < len; i += 2) {
v.val.ec = ec_get(l, i);
/* pos && member(val, set) || !pos && !member(val, set), member() depends on tree */
if ((tree ? !!find_tree(set.val.t, v) : ec_set_contains(set.val.ad, v.val.ec)) == pos) {
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*k++ = l[i];
*k++ = l[i+1];
}
}
uint nl = (k - tmp) * sizeof(u32);
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if (nl == list->length)
return list;
struct adata *res = adata_empty(pool, nl);
memcpy(res->data, tmp, nl);
return res;
}
static struct adata *
lclist_filter(struct linpool *pool, struct adata *list, struct f_val set, int pos)
{
if (!list)
return NULL;
int tree = (set.type == T_SET); /* 1 -> set is T_SET, 0 -> set is T_CLIST */
struct f_val v;
int len = int_set_get_size(list);
u32 *l = int_set_get_data(list);
u32 tmp[len];
u32 *k = tmp;
int i;
v.type = T_LC;
for (i = 0; i < len; i += 3) {
v.val.lc = lc_get(l, i);
/* pos && member(val, set) || !pos && !member(val, set), member() depends on tree */
if ((tree ? !!find_tree(set.val.t, v) : lc_set_contains(set.val.ad, v.val.lc)) == pos)
k = lc_copy(k, l+i);
}
uint nl = (k - tmp) * sizeof(u32);
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if (nl == list->length)
return list;
struct adata *res = adata_empty(pool, nl);
memcpy(res->data, tmp, nl);
return res;
}
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/**
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* val_in_range - implement |~| operator
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* @v1: element
* @v2: set
*
* Checks if @v1 is element (|~| operator) of @v2.
*/
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static int
val_in_range(struct f_val v1, struct f_val v2)
{
if ((v1.type == T_PATH) && (v2.type == T_PATH_MASK))
return as_path_match(v1.val.ad, v2.val.path_mask);
if ((v1.type == T_INT) && (v2.type == T_PATH))
return as_path_contains(v2.val.ad, v1.val.i, 1);
if (((v1.type == T_PAIR) || (v1.type == T_QUAD)) && (v2.type == T_CLIST))
return int_set_contains(v2.val.ad, v1.val.i);
/* IP->Quad implicit conversion */
if (val_is_ip4(v1) && (v2.type == T_CLIST))
return int_set_contains(v2.val.ad, ipa_to_u32(v1.val.ip));
if ((v1.type == T_EC) && (v2.type == T_ECLIST))
return ec_set_contains(v2.val.ad, v1.val.ec);
if ((v1.type == T_LC) && (v2.type == T_LCLIST))
return lc_set_contains(v2.val.ad, v1.val.lc);
if ((v1.type == T_STRING) && (v2.type == T_STRING))
return patmatch(v2.val.s, v1.val.s);
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if ((v1.type == T_IP) && (v2.type == T_NET))
return ipa_in_netX(v1.val.ip, v2.val.net);
if ((v1.type == T_NET) && (v2.type == T_NET))
return net_in_netX(v1.val.net, v2.val.net);
if ((v1.type == T_NET) && (v2.type == T_PREFIX_SET))
return trie_match_net(v2.val.ti, v1.val.net);
if (v2.type != T_SET)
return CMP_ERROR;
/* With integrated Quad<->IP implicit conversion */
if ((v1.type == v2.val.t->from.type) ||
((v1.type == T_QUAD) && val_is_ip4(v2.val.t->from) && val_is_ip4(v2.val.t->to)))
return !!find_tree(v2.val.t, v1);
if (v1.type == T_CLIST)
return clist_match_set(v1.val.ad, v2.val.t);
if (v1.type == T_ECLIST)
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return eclist_match_set(v1.val.ad, v2.val.t);
if (v1.type == T_LCLIST)
return lclist_match_set(v1.val.ad, v2.val.t);
if (v1.type == T_PATH)
return as_path_match_set(v1.val.ad, v2.val.t);
return CMP_ERROR;
}
/*
* val_format - format filter value
*/
void
val_format(struct f_val v, buffer *buf)
{
char buf2[1024];
switch (v.type)
{
case T_VOID: buffer_puts(buf, "(void)"); return;
case T_BOOL: buffer_puts(buf, v.val.i ? "TRUE" : "FALSE"); return;
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case T_INT: buffer_print(buf, "%u", v.val.i); return;
case T_STRING: buffer_print(buf, "%s", v.val.s); return;
case T_IP: buffer_print(buf, "%I", v.val.ip); return;
case T_NET: buffer_print(buf, "%N", v.val.net); return;
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case T_PAIR: buffer_print(buf, "(%u,%u)", v.val.i >> 16, v.val.i & 0xffff); return;
case T_QUAD: buffer_print(buf, "%R", v.val.i); return;
case T_EC: ec_format(buf2, v.val.ec); buffer_print(buf, "%s", buf2); return;
case T_LC: lc_format(buf2, v.val.lc); buffer_print(buf, "%s", buf2); return;
case T_RD: rd_format(v.val.ec, buf2, 1024); buffer_print(buf, "%s", buf2); return;
case T_PREFIX_SET: trie_format(v.val.ti, buf); return;
case T_SET: tree_format(v.val.t, buf); return;
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case T_ENUM: buffer_print(buf, "(enum %x)%u", v.type, v.val.i); return;
case T_PATH: as_path_format(v.val.ad, buf2, 1000); buffer_print(buf, "(path %s)", buf2); return;
case T_CLIST: int_set_format(v.val.ad, 1, -1, buf2, 1000); buffer_print(buf, "(clist %s)", buf2); return;
case T_ECLIST: ec_set_format(v.val.ad, -1, buf2, 1000); buffer_print(buf, "(eclist %s)", buf2); return;
case T_LCLIST: lc_set_format(v.val.ad, -1, buf2, 1000); buffer_print(buf, "(lclist %s)", buf2); return;
case T_PATH_MASK: pm_format(v.val.path_mask, buf); return;
default: buffer_print(buf, "[unknown type %x]", v.type); return;
}
}
static inline void f_cache_eattrs(struct filter_state *fs)
{
fs->eattrs = &((*fs->rte)->attrs->eattrs);
}
static inline void f_rte_cow(struct filter_state *fs)
{
if (!((*fs->rte)->flags & REF_COW))
return;
*fs->rte = rte_cow(*fs->rte);
}
/*
* rta_cow - prepare rta for modification by filter
*/
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static void
f_rta_cow(struct filter_state *fs)
{
if (!rta_is_cached((*fs->rte)->attrs))
return;
/* Prepare to modify rte */
f_rte_cow(fs);
/* Store old rta to free it later, it stores reference from rte_cow() */
fs->old_rta = (*fs->rte)->attrs;
/*
* Get shallow copy of rta. Fields eattrs and nexthops of rta are shared
* with fs->old_rta (they will be copied when the cached rta will be obtained
* at the end of f_run()), also the lock of hostentry is inherited (we
* suppose hostentry is not changed by filters).
*/
(*fs->rte)->attrs = rta_do_cow((*fs->rte)->attrs, fs->pool);
/* Re-cache the ea_list */
f_cache_eattrs(fs);
}
static char *
val_format_str(struct filter_state *fs, struct f_val v) {
buffer b;
LOG_BUFFER_INIT(b);
val_format(v, &b);
return lp_strdup(fs->pool, b.start);
}
static struct tbf rl_runtime_err = TBF_DEFAULT_LOG_LIMITS;
/**
* interpret
* @fs: filter state
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* @what: filter to interpret
*
* Interpret given tree of filter instructions. This is core function
* of filter system and does all the hard work.
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*
* Each instruction has 4 fields: code (which is instruction code),
* aux (which is extension to instruction code, typically type),
* arg1 and arg2 - arguments. Depending on instruction, arguments
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* are either integers, or pointers to instruction trees. Common
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* instructions like +, that have two expressions as arguments use
* TWOARGS macro to get both of them evaluated.
*/
static enum filter_return
interpret(struct filter_state *fs, struct f_inst *what)
{
struct symbol *sym;
struct f_val *vp;
unsigned u1, u2;
enum filter_return fret;
int i;
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u32 as;
#define res fs->stack[fs->stack_ptr].val
#define v0 res
#define v1 fs->stack[fs->stack_ptr + 1].val
#define v2 fs->stack[fs->stack_ptr + 2].val
#define v3 fs->stack[fs->stack_ptr + 3].val
res = (struct f_val) { .type = T_VOID };
for ( ; what; what = what->next) {
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res = (struct f_val) { .type = T_VOID };
switch (what->fi_code) {
#define runtime(fmt, ...) do { \
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if (!(fs->flags & FF_SILENT)) \
log_rl(&rl_runtime_err, L_ERR "filters, line %d: " fmt, what->lineno, ##__VA_ARGS__); \
return F_ERROR; \
} while(0)
#define ARG_ANY_T(n, tt) INTERPRET(what->a##n.p, tt)
#define ARG_ANY(n) ARG_ANY_T(n, n)
#define ARG_T(n,tt,t) do { \
ARG_ANY_T(n,tt); \
if (v##tt.type != t) \
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runtime("Argument %d of instruction %s must be of type %02x, got %02x", \
n, f_instruction_name(what->fi_code), t, v##tt.type); \
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} while (0)
#define ARG(n,t) ARG_T(n,n,t)
#define INTERPRET(what_, n) do { \
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fs->stack_ptr += n; \
fret = interpret(fs, what_); \
fs->stack_ptr -= n; \
if (fret == F_RETURN) \
bug("This shall not happen"); \
if (fret > F_RETURN) \
return fret; \
} while (0)
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#define ACCESS_RTE do { if (!fs->rte) runtime("No route to access"); } while (0)
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#define ACCESS_EATTRS do { if (!fs->eattrs) f_cache_eattrs(fs); } while (0)
#define BITFIELD_MASK(what_) (1u << EA_BIT_GET(what_->a2.i))
#include "filter/f-inst.c"
#undef res
#undef runtime
#undef ARG_ANY
#undef ARG
#undef INTERPRET
#undef ACCESS_RTE
#undef ACCESS_EATTRS
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}
}
return F_NOP;
}
#define ARG(n) \
if (!i_same(f1->a##n.p, f2->a##n.p)) \
return 0;
#define ONEARG ARG(1);
#define TWOARGS ONEARG; ARG(2);
#define THREEARGS TWOARGS; ARG(3);
#define A2_SAME if (f1->a2.i != f2->a2.i) return 0;
/*
* i_same - function that does real comparing of instruction trees, you should call filter_same from outside
*/
int
i_same(struct f_inst *f1, struct f_inst *f2)
{
if ((!!f1) != (!!f2))
return 0;
if (!f1)
return 1;
if (f1->aux != f2->aux)
return 0;
if (f1->fi_code != f2->fi_code)
return 0;
if (f1 == f2) /* It looks strange, but it is possible with call rewriting trickery */
return 1;
switch(f1->fi_code) {
case FI_ADD: /* fall through */
case FI_SUBTRACT:
case FI_MULTIPLY:
case FI_DIVIDE:
case FI_OR:
case FI_AND:
case FI_PAIR_CONSTRUCT:
case FI_EC_CONSTRUCT:
case FI_NEQ:
case FI_EQ:
case FI_LT:
case FI_LTE: TWOARGS; break;
case FI_PATHMASK_CONSTRUCT: if (!pm_same(f1->a1.p, f2->a1.p)) return 0; break;
case FI_NOT: ONEARG; break;
case FI_NOT_MATCH:
case FI_MATCH: TWOARGS; break;
case FI_DEFINED: ONEARG; break;
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case FI_TYPE: ONEARG; break;
case FI_LC_CONSTRUCT:
THREEARGS;
break;
case FI_SET:
ARG(2);
{
struct symbol *s1, *s2;
s1 = f1->a1.p;
s2 = f2->a1.p;
if (strcmp(s1->name, s2->name))
return 0;
if (s1->class != s2->class)
return 0;
}
break;
case FI_CONSTANT:
switch (f1->aux) {
case T_PREFIX_SET:
if (!trie_same(f1->a2.p, f2->a2.p))
return 0;
break;
case T_SET:
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if (!same_tree(f1->a2.p, f2->a2.p))
return 0;
break;
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case T_STRING:
if (strcmp(f1->a2.p, f2->a2.p))
return 0;
break;
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default:
A2_SAME;
}
break;
case FI_CONSTANT_INDIRECT:
if (!val_same(* (struct f_val *) f1->a1.p, * (struct f_val *) f2->a1.p))
return 0;
break;
case FI_VARIABLE:
if (strcmp((char *) f1->a2.p, (char *) f2->a2.p))
return 0;
break;
case FI_PRINT: case FI_LENGTH: ONEARG; break;
case FI_CONDITION: TWOARGS; break;
case FI_NOP: case FI_EMPTY: break;
case FI_PRINT_AND_DIE: ONEARG; A2_SAME; break;
case FI_PREF_GET:
case FI_RTA_GET: A2_SAME; break;
case FI_EA_GET: A2_SAME; break;
case FI_PREF_SET:
case FI_RTA_SET:
case FI_EA_SET: ONEARG; A2_SAME; break;
case FI_RETURN: ONEARG; break;
case FI_ROA_MAXLEN: ONEARG; break;
case FI_ROA_ASN: ONEARG; break;
case FI_SADR_SRC: ONEARG; break;
case FI_IP: ONEARG; break;
case FI_IS_V4: ONEARG; break;
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case FI_ROUTE_DISTINGUISHER: ONEARG; break;
case FI_CALL: /* Call rewriting trickery to avoid exponential behaviour */
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ONEARG;
if (!i_same(f1->a2.p, f2->a2.p))
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return 0;
f2->a2.p = f1->a2.p;
break;
case FI_CLEAR_LOCAL_VARS: break; /* internal instruction */
case FI_SWITCH: ONEARG; if (!same_tree(f1->a2.p, f2->a2.p)) return 0; break;
case FI_IP_MASK: TWOARGS; break;
case FI_PATH_PREPEND: TWOARGS; break;
case FI_CLIST_ADD_DEL: TWOARGS; break;
case FI_AS_PATH_FIRST:
case FI_AS_PATH_LAST:
case FI_AS_PATH_LAST_NAG: ONEARG; break;
case FI_ROA_CHECK:
TWOARGS;
/* Does not really make sense - ROA check results may change anyway */
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if (strcmp(((struct f_inst_roa_check *) f1)->rtc->name,
((struct f_inst_roa_check *) f2)->rtc->name))
return 0;
break;
case FI_FORMAT: ONEARG; break;
case FI_ASSERT: ONEARG; break;
default:
bug( "Unknown instruction %d in same (%c)", f1->fi_code, f1->fi_code & 0xff);
}
return i_same(f1->next, f2->next);
}
/**
* f_run - run a filter for a route
* @filter: filter to run
* @rte: route being filtered, may be modified
* @tmp_pool: all filter allocations go from this pool
* @flags: flags
*
* If filter needs to modify the route, there are several
* posibilities. @rte might be read-only (with REF_COW flag), in that
* case rw copy is obtained by rte_cow() and @rte is replaced. If
* @rte is originally rw, it may be directly modified (and it is never
* copied).
*
* The returned rte may reuse the (possibly cached, cloned) rta, or
* (if rta was modificied) contains a modified uncached rta, which
* uses parts allocated from @tmp_pool and parts shared from original
* rta. There is one exception - if @rte is rw but contains a cached
* rta and that is modified, rta in returned rte is also cached.
*
* Ownership of cached rtas is consistent with rte, i.e.
* if a new rte is returned, it has its own clone of cached rta
* (and cached rta of read-only source rte is intact), if rte is
* modified in place, old cached rta is possibly freed.
*/
enum filter_return
f_run(struct filter *filter, struct rte **rte, struct linpool *tmp_pool, int flags)
{
if (filter == FILTER_ACCEPT)
return F_ACCEPT;
if (filter == FILTER_REJECT)
return F_REJECT;
int rte_cow = ((*rte)->flags & REF_COW);
DBG( "Running filter `%s'...", filter->name );
struct filter_state fs = {
.rte = rte,
.pool = tmp_pool,
.flags = flags,
.stack = filter_stack,
};
LOG_BUFFER_INIT(fs.buf);
enum filter_return fret = interpret(&fs, filter->root);
if (fs.old_rta) {
/*
* Cached rta was modified and fs->rte contains now an uncached one,
* sharing some part with the cached one. The cached rta should
* be freed (if rte was originally COW, fs->old_rta is a clone
* obtained during rte_cow()).
*
* This also implements the exception mentioned in f_run()
* description. The reason for this is that rta reuses parts of
* fs->old_rta, and these may be freed during rta_free(fs->old_rta).
* This is not the problem if rte was COW, because original rte
* also holds the same rta.
*/
if (!rte_cow)
(*fs.rte)->attrs = rta_lookup((*fs.rte)->attrs);
rta_free(fs.old_rta);
}
if (fret < F_ACCEPT) {
if (!(fs.flags & FF_SILENT))
log_rl(&rl_runtime_err, L_ERR "Filter %s did not return accept nor reject. Make up your mind", filter->name);
return F_ERROR;
}
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DBG( "done (%u)\n", res.val.i );
return fret;
}
/* TODO: perhaps we could integrate f_eval(), f_eval_rte() and f_run() */
enum filter_return
f_eval_rte(struct f_inst *expr, struct rte **rte, struct linpool *tmp_pool)
{
struct filter_state fs = {
.rte = rte,
.pool = tmp_pool,
.stack = filter_stack,
};
LOG_BUFFER_INIT(fs.buf);
/* Note that in this function we assume that rte->attrs is private / uncached */
return interpret(&fs, expr);
}
enum filter_return
f_eval(struct f_inst *expr, struct linpool *tmp_pool, struct f_val *pres)
{
struct filter_state fs = {
.pool = tmp_pool,
.stack = filter_stack,
};
LOG_BUFFER_INIT(fs.buf);
enum filter_return fret = interpret(&fs, expr);
*pres = filter_stack[0].val;
return fret;
}
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uint
f_eval_int(struct f_inst *expr)
{
/* Called independently in parse-time to eval expressions */
struct filter_state fs = {
.pool = cfg_mem,
.stack = filter_stack,
};
LOG_BUFFER_INIT(fs.buf);
if (interpret(&fs, expr) > F_RETURN)
cf_error("Runtime error while evaluating expression");
if (filter_stack[0].val.type != T_INT)
cf_error("Integer expression expected");
return filter_stack[0].val.val.i;
}
/**
* filter_same - compare two filters
* @new: first filter to be compared
* @old: second filter to be compared, notice that this filter is
* damaged while comparing.
*
* Returns 1 in case filters are same, otherwise 0. If there are
* underlying bugs, it will rather say 0 on same filters than say
* 1 on different.
*/
int
filter_same(struct filter *new, struct filter *old)
{
if (old == new) /* Handle FILTER_ACCEPT and FILTER_REJECT */
return 1;
if (old == FILTER_ACCEPT || old == FILTER_REJECT ||
new == FILTER_ACCEPT || new == FILTER_REJECT)
return 0;
return i_same(new->root, old->root);
}