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bird/filter/filter.c
Ondrej Zajicek 36da2857bc Implements router advertisements activated by received routes. 
The RAdv protocol could be configured to change its behavior based on
availability of routes, e.g., do not announce router lifetime when a
default route is not available.
2013-02-08 23:58:27 +01:00

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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
*
* 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|.
*
* 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.
*
* 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 "nest/route.h"
#include "nest/protocol.h"
#include "nest/iface.h"
#include "nest/attrs.h"
#include "conf/conf.h"
#include "filter/filter.h"
#define P(a,b) ((a<<8) | b)
#define CMP_ERROR 999
static struct adata *
adata_empty(struct linpool *pool, int l)
{
struct adata *res = lp_alloc(pool, sizeof(struct adata) + l);
res->length = l;
return res;
}
static int
pm_path_compare(struct f_path_mask *m1, struct f_path_mask *m2)
{
while (1) {
if ((!m1) || (!m2))
return !((!m1) && (!m2));
/* FIXME: buggy, should return -1, 0, 1; but it doesn't matter */
if ((m1->kind != m2->kind) || (m1->val != m2->val)) return 1;
m1 = m1->next;
m2 = m2->next;
}
}
u32 f_eval_asn(struct f_inst *expr);
static void
pm_format(struct f_path_mask *p, byte *buf, unsigned int size)
{
byte *end = buf + size - 16;
while (p)
{
if (buf > end)
{
strcpy(buf, " ...");
return;
}
switch(p->kind)
{
case PM_ASN:
buf += bsprintf(buf, " %u", p->val);
break;
case PM_QUESTION:
buf += bsprintf(buf, " ?");
break;
case PM_ASTERISK:
buf += bsprintf(buf, " *");
break;
case PM_ASN_EXPR:
buf += bsprintf(buf, " %u", f_eval_asn((struct f_inst *) p->val));
break;
}
p = p->next;
}
*buf = 0;
}
static inline int int_cmp(int i1, int i2)
{
if (i1 == i2) return 0;
if (i1 < i2) return -1;
else return 1;
}
static inline int uint_cmp(unsigned int i1, unsigned int i2)
{
if (i1 == i2) return 0;
if (i1 < i2) return -1;
else return 1;
}
static inline int u64_cmp(u64 i1, u64 i2)
{
if (i1 == i2) return 0;
if (i1 < i2) return -1;
else return 1;
}
/**
* val_compare - compare two values
* @v1: first value
* @v2: second value
*
* Compares two values and returns -1, 0, 1 on <, =, > or 999 on error.
* Tree module relies on this giving consistent results so that it can
* build balanced trees.
*/
int
val_compare(struct f_val v1, struct f_val v2)
{
int rc;
if ((v1.type == T_VOID) && (v2.type == T_VOID))
return 0;
if (v1.type == T_VOID) /* Hack for else */
return -1;
if (v2.type == T_VOID)
return 1;
if (v1.type != v2.type) {
#ifndef IPV6
/* IP->Quad implicit conversion */
if ((v1.type == T_QUAD) && (v2.type == T_IP))
return uint_cmp(v1.val.i, ipa_to_u32(v2.val.px.ip));
if ((v1.type == T_IP) && (v2.type == T_QUAD))
return uint_cmp(ipa_to_u32(v1.val.px.ip), v2.val.i);
#endif
debug( "Types do not match in val_compare\n" );
return CMP_ERROR;
}
switch (v1.type) {
case T_ENUM:
case T_INT:
case T_BOOL:
return int_cmp(v1.val.i, v2.val.i);
case T_PAIR:
case T_QUAD:
return uint_cmp(v1.val.i, v2.val.i);
case T_EC:
return u64_cmp(v1.val.ec, v2.val.ec);
case T_IP:
return ipa_compare(v1.val.px.ip, v2.val.px.ip);
case T_PREFIX:
if (rc = ipa_compare(v1.val.px.ip, v2.val.px.ip))
return rc;
if (v1.val.px.len < v2.val.px.len)
return -1;
if (v1.val.px.len > v2.val.px.len)
return 1;
return 0;
case T_PATH_MASK:
return pm_path_compare(v1.val.path_mask, v2.val.path_mask);
case T_STRING:
return strcmp(v1.val.s, v2.val.s);
default:
debug( "Compare of unknown entities: %x\n", v1.type );
return CMP_ERROR;
}
}
int
tree_compare(const void *p1, const void *p2)
{
return val_compare((* (struct f_tree **) p1)->from, (* (struct f_tree **) p2)->from);
}
void
fprefix_get_bounds(struct f_prefix *px, int *l, int *h)
{
*l = *h = px->len & LEN_MASK;
if (px->len & LEN_MINUS)
*l = 0;
else if (px->len & LEN_PLUS)
*h = MAX_PREFIX_LENGTH;
else if (px->len & LEN_RANGE)
{
*l = 0xff & (px->len >> 16);
*h = 0xff & (px->len >> 8);
}
}
/*
* val_simple_in_range - check if @v1 ~ @v2 for everything except sets
*/
static int
val_simple_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_is_member(v2.val.ad, v1.val.i);
if (((v1.type == T_PAIR) || (v1.type == T_QUAD)) && (v2.type == T_CLIST))
return int_set_contains(v2.val.ad, v1.val.i);
#ifndef IPV6
/* IP->Quad implicit conversion */
if ((v1.type == T_IP) && (v2.type == T_CLIST))
return int_set_contains(v2.val.ad, ipa_to_u32(v1.val.px.ip));
#endif
if ((v1.type == T_EC) && (v2.type == T_ECLIST))
return ec_set_contains(v2.val.ad, v1.val.ec);
if ((v1.type == T_STRING) && (v2.type == T_STRING))
return patmatch(v2.val.s, v1.val.s);
if ((v1.type == T_IP) && (v2.type == T_PREFIX))
return ipa_in_net(v1.val.px.ip, v2.val.px.ip, v2.val.px.len);
if ((v1.type == T_PREFIX) && (v2.type == T_PREFIX))
return net_in_net(v1.val.px.ip, v1.val.px.len, v2.val.px.ip, v2.val.px.len);
return CMP_ERROR;
}
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:
#ifndef IPV6
case T_IP:
#endif
v->type = T_QUAD;
return 1;
break;
default:
v->type = T_VOID;
return 0;
}
}
static inline int
eclist_set_type(struct f_tree *set)
{ return set->from.type == T_EC; }
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;
while (l < end) {
v.val.i = *l++;
if (find_tree(set, v))
return 1;
}
return 0;
}
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 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;
}
int nl = (k - tmp) * 4;
if (nl == list->length)
return list;
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)
{
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_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) {
*k++ = l[i];
*k++ = l[i+1];
}
}
int nl = (k - tmp) * 4;
if (nl == list->length)
return list;
struct adata *res = adata_empty(pool, nl);
memcpy(res->data, tmp, nl);
return res;
}
/**
* val_in_range - implement |~| operator
* @v1: element
* @v2: set
*
* Checks if @v1 is element (|~| operator) of @v2. Sets are internally represented as balanced trees, see
* |tree.c| module (this is not limited to sets, but for non-set cases, val_simple_in_range() is called early).
*/
static int
val_in_range(struct f_val v1, struct f_val v2)
{
int res;
res = val_simple_in_range(v1, v2);
if (res != CMP_ERROR)
return res;
if ((v1.type == T_PREFIX) && (v2.type == T_PREFIX_SET))
return trie_match_fprefix(v2.val.ti, &v1.val.px);
if ((v1.type == T_CLIST) && (v2.type == T_SET))
return clist_match_set(v1.val.ad, v2.val.t);
if ((v1.type == T_ECLIST) && (v2.type == T_SET))
return eclist_match_set(v1.val.ad, v2.val.t);
if (v2.type == T_SET)
switch (v1.type) {
case T_ENUM:
case T_INT:
case T_PAIR:
case T_QUAD:
case T_IP:
case T_EC:
{
struct f_tree *n;
n = find_tree(v2.val.t, v1);
if (!n)
return 0;
return !! (val_simple_in_range(v1, n->from)); /* We turn CMP_ERROR into compared ok, and that's fine */
}
}
return CMP_ERROR;
}
static void val_print(struct f_val v);
static void
tree_node_print(struct f_tree *t, char **sep)
{
if (t == NULL)
return;
tree_node_print(t->left, sep);
logn(*sep);
val_print(t->from);
if (val_compare(t->from, t->to) != 0)
{
logn( ".." );
val_print(t->to);
}
*sep = ", ";
tree_node_print(t->right, sep);
}
static void
tree_print(struct f_tree *t)
{
char *sep = "";
logn( "[" );
tree_node_print(t, &sep);
logn( "] " );
}
/*
* val_print - format filter value
*/
static void
val_print(struct f_val v)
{
char buf2[1024];
switch (v.type) {
case T_VOID: logn("(void)"); return;
case T_BOOL: logn(v.val.i ? "TRUE" : "FALSE"); return;
case T_INT: logn("%d", v.val.i); return;
case T_STRING: logn("%s", v.val.s); return;
case T_IP: logn("%I", v.val.px.ip); return;
case T_PREFIX: logn("%I/%d", v.val.px.ip, v.val.px.len); return;
case T_PAIR: logn("(%d,%d)", v.val.i >> 16, v.val.i & 0xffff); return;
case T_QUAD: logn("%R", v.val.i); return;
case T_EC: ec_format(buf2, v.val.ec); logn("%s", buf2); return;
case T_PREFIX_SET: trie_print(v.val.ti); return;
case T_SET: tree_print(v.val.t); return;
case T_ENUM: logn("(enum %x)%d", v.type, v.val.i); return;
case T_PATH: as_path_format(v.val.ad, buf2, 1000); logn("(path %s)", buf2); return;
case T_CLIST: int_set_format(v.val.ad, 1, -1, buf2, 1000); logn("(clist %s)", buf2); return;
case T_ECLIST: ec_set_format(v.val.ad, -1, buf2, 1000); logn("(eclist %s)", buf2); return;
case T_PATH_MASK: pm_format(v.val.path_mask, buf2, 1000); logn("(pathmask%s)", buf2); return;
default: logn( "[unknown type %x]", v.type ); return;
}
}
static struct rte **f_rte;
static struct rta *f_old_rta;
static struct ea_list **f_tmp_attrs;
static struct linpool *f_pool;
static int f_flags;
static inline void f_rte_cow(void)
{
*f_rte = rte_cow(*f_rte);
}
/*
* rta_cow - prepare rta for modification by filter
*/
static void
f_rta_cow(void)
{
if ((*f_rte)->attrs->aflags & RTAF_CACHED) {
/* Prepare to modify rte */
f_rte_cow();
/* Store old rta to free it later */
f_old_rta = (*f_rte)->attrs;
/*
* Alloc new rta, do shallow copy and update rte. Fields eattrs
* and nexthops of rta are shared with f_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).
*/
rta *ra = lp_alloc(f_pool, sizeof(rta));
memcpy(ra, f_old_rta, sizeof(rta));
ra->aflags = 0;
(*f_rte)->attrs = ra;
}
}
static struct rate_limit rl_runtime_err;
#define runtime(x) do { \
log_rl(&rl_runtime_err, L_ERR "filters, line %d: %s", what->lineno, x); \
res.type = T_RETURN; \
res.val.i = F_ERROR; \
return res; \
} while(0)
#define ARG(x,y) \
x = interpret(what->y); \
if (x.type & T_RETURN) \
return x;
#define ONEARG ARG(v1, a1.p)
#define TWOARGS ARG(v1, a1.p) \
ARG(v2, a2.p)
#define TWOARGS_C TWOARGS \
if (v1.type != v2.type) \
runtime( "Can't operate with values of incompatible types" );
/**
* interpret
* @what: filter to interpret
*
* Interpret given tree of filter instructions. This is core function
* of filter system and does all the hard work.
*
* 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
* are either integers, or pointers to instruction trees. Common
* instructions like +, that have two expressions as arguments use
* TWOARGS macro to get both of them evaluated.
*
* &f_val structures are copied around, so there are no problems with
* memory managment.
*/
static struct f_val
interpret(struct f_inst *what)
{
struct symbol *sym;
struct f_val v1, v2, res, *vp;
unsigned u1, u2;
int i;
u32 as;
res.type = T_VOID;
if (!what)
return res;
switch(what->code) {
case ',':
TWOARGS;
break;
/* Binary operators */
case '+':
TWOARGS_C;
switch (res.type = v1.type) {
case T_VOID: runtime( "Can't operate with values of type void" );
case T_INT: res.val.i = v1.val.i + v2.val.i; break;
default: runtime( "Usage of unknown type" );
}
break;
case '-':
TWOARGS_C;
switch (res.type = v1.type) {
case T_VOID: runtime( "Can't operate with values of type void" );
case T_INT: res.val.i = v1.val.i - v2.val.i; break;
default: runtime( "Usage of unknown type" );
}
break;
case '*':
TWOARGS_C;
switch (res.type = v1.type) {
case T_VOID: runtime( "Can't operate with values of type void" );
case T_INT: res.val.i = v1.val.i * v2.val.i; break;
default: runtime( "Usage of unknown type" );
}
break;
case '/':
TWOARGS_C;
switch (res.type = v1.type) {
case T_VOID: runtime( "Can't operate with values of type void" );
case T_INT: if (v2.val.i == 0) runtime( "Mother told me not to divide by 0" );
res.val.i = v1.val.i / v2.val.i; break;
default: runtime( "Usage of unknown type" );
}
break;
case '&':
case '|':
ARG(v1, a1.p);
if (v1.type != T_BOOL)
runtime( "Can't do boolean operation on non-booleans" );
if (v1.val.i == (what->code == '|')) {
res.type = T_BOOL;
res.val.i = v1.val.i;
break;
}
ARG(v2, a2.p);
if (v2.type != T_BOOL)
runtime( "Can't do boolean operation on non-booleans" );
res.type = T_BOOL;
res.val.i = v2.val.i;
break;
case P('m','p'):
TWOARGS;
if ((v1.type != T_INT) || (v2.type != T_INT))
runtime( "Can't operate with value of non-integer type in pair constructor" );
u1 = v1.val.i;
u2 = v2.val.i;
if ((u1 > 0xFFFF) || (u2 > 0xFFFF))
runtime( "Can't operate with value out of bounds in pair constructor" );
res.val.i = (u1 << 16) | u2;
res.type = T_PAIR;
break;
case P('m','c'):
{
TWOARGS;
int check, ipv4_used;
u32 key, val;
if (v1.type == T_INT) {
ipv4_used = 0; key = v1.val.i;
}
else if (v1.type == T_QUAD) {
ipv4_used = 1; key = v1.val.i;
}
#ifndef IPV6
/* IP->Quad implicit conversion */
else if (v1.type == T_IP) {
ipv4_used = 1; key = ipa_to_u32(v1.val.px.ip);
}
#endif
else
runtime("Can't operate with key of non-integer/IPv4 type in EC constructor");
if (v2.type != T_INT)
runtime("Can't operate with value of non-integer type in EC constructor");
val = v2.val.i;
res.type = T_EC;
if (what->aux == EC_GENERIC) {
check = 0; res.val.ec = ec_generic(key, val);
}
else if (ipv4_used) {
check = 1; res.val.ec = ec_ip4(what->aux, key, val);
}
else if (key < 0x10000) {
check = 0; res.val.ec = ec_as2(what->aux, key, val);
}
else {
check = 1; res.val.ec = ec_as4(what->aux, key, val);
}
if (check && (val > 0xFFFF))
runtime("Can't operate with value out of bounds in EC constructor");
break;
}
/* Relational operators */
#define COMPARE(x) \
TWOARGS; \
i = val_compare(v1, v2); \
if (i==CMP_ERROR) \
runtime( "Can't compare values of incompatible types" ); \
res.type = T_BOOL; \
res.val.i = (x); \
break;
case P('!','='): COMPARE(i!=0);
case P('=','='): COMPARE(i==0);
case '<': COMPARE(i==-1);
case P('<','='): COMPARE(i!=1);
case '!':
ONEARG;
if (v1.type != T_BOOL)
runtime( "Not applied to non-boolean" );
res = v1;
res.val.i = !res.val.i;
break;
case '~':
TWOARGS;
res.type = T_BOOL;
res.val.i = val_in_range(v1, v2);
if (res.val.i == CMP_ERROR)
runtime( "~ applied on unknown type pair" );
res.val.i = !!res.val.i;
break;
case P('d','e'):
ONEARG;
res.type = T_BOOL;
res.val.i = (v1.type != T_VOID);
break;
/* Set to indirect value, a1 = variable, a2 = value */
case 's':
ARG(v2, a2.p);
sym = what->a1.p;
vp = sym->def;
if ((sym->class != (SYM_VARIABLE | v2.type)) && (v2.type != T_VOID)) {
#ifndef IPV6
/* IP->Quad implicit conversion */
if ((sym->class == (SYM_VARIABLE | T_QUAD)) && (v2.type == T_IP)) {
vp->type = T_QUAD;
vp->val.i = ipa_to_u32(v2.val.px.ip);
break;
}
#endif
runtime( "Assigning to variable of incompatible type" );
}
*vp = v2;
break;
/* some constants have value in a2, some in *a1.p, strange. */
case 'c': /* integer (or simple type) constant, string, set, or prefix_set */
res.type = what->aux;
if (res.type == T_PREFIX_SET)
res.val.ti = what->a2.p;
else if (res.type == T_SET)
res.val.t = what->a2.p;
else if (res.type == T_STRING)
res.val.s = what->a2.p;
else
res.val.i = what->a2.i;
break;
case 'V':
case 'C':
res = * ((struct f_val *) what->a1.p);
break;
case 'p':
ONEARG;
val_print(v1);
break;
case '?': /* ? has really strange error value, so we can implement if ... else nicely :-) */
ONEARG;
if (v1.type != T_BOOL)
runtime( "If requires boolean expression" );
if (v1.val.i) {
ARG(res,a2.p);
res.val.i = 0;
} else res.val.i = 1;
res.type = T_BOOL;
break;
case '0':
debug( "No operation\n" );
break;
case P('p',','):
ONEARG;
if (what->a2.i == F_NOP || (what->a2.i != F_NONL && what->a1.p))
log_commit(*L_INFO);
switch (what->a2.i) {
case F_QUITBIRD:
die( "Filter asked me to die" );
case F_ACCEPT:
/* Should take care about turning ACCEPT into MODIFY */
case F_ERROR:
case F_REJECT: /* FIXME (noncritical) Should print complete route along with reason to reject route */
res.type = T_RETURN;
res.val.i = what->a2.i;
return res; /* We have to return now, no more processing. */
case F_NONL:
case F_NOP:
break;
default:
bug( "unknown return type: Can't happen");
}
break;
case 'a': /* rta access */
{
struct rta *rta = (*f_rte)->attrs;
res.type = what->aux;
switch(res.type) {
case T_IP:
res.val.px.ip = * (ip_addr *) ((char *) rta + what->a2.i);
break;
case T_ENUM:
res.val.i = * ((char *) rta + what->a2.i);
break;
case T_STRING: /* Warning: this is a special case for proto attribute */
res.val.s = rta->proto->name;
break;
case T_PREFIX: /* Warning: this works only for prefix of network */
{
res.val.px.ip = (*f_rte)->net->n.prefix;
res.val.px.len = (*f_rte)->net->n.pxlen;
break;
}
default:
bug( "Invalid type for rta access (%x)", res.type );
}
}
break;
case P('a','S'):
ONEARG;
if (what->aux != v1.type)
runtime( "Attempt to set static attribute to incompatible type" );
f_rta_cow();
{
struct rta *rta = (*f_rte)->attrs;
switch (what->aux) {
case T_IP:
* (ip_addr *) ((char *) rta + what->a2.i) = v1.val.px.ip;
break;
case T_ENUM_SCOPE:
rta->scope = v1.val.i;
break;
case T_ENUM_RTD:
i = v1.val.i;
if ((i != RTD_BLACKHOLE) && (i != RTD_UNREACHABLE) && (i != RTD_PROHIBIT))
runtime( "Destination can be changed only to blackhole, unreachable or prohibit" );
rta->dest = i;
rta->gw = IPA_NONE;
rta->iface = NULL;
rta->nexthops = NULL;
break;
default:
bug( "Unknown type in set of static attribute" );
}
}
break;
case P('e','a'): /* Access to extended attributes */
{
eattr *e = NULL;
if (!(f_flags & FF_FORCE_TMPATTR))
e = ea_find( (*f_rte)->attrs->eattrs, what->a2.i );
if (!e)
e = ea_find( (*f_tmp_attrs), what->a2.i );
if ((!e) && (f_flags & FF_FORCE_TMPATTR))
e = ea_find( (*f_rte)->attrs->eattrs, what->a2.i );
if (!e) {
/* A special case: undefined int_set looks like empty int_set */
if ((what->aux & EAF_TYPE_MASK) == EAF_TYPE_INT_SET) {
res.type = T_CLIST;
res.val.ad = adata_empty(f_pool, 0);
break;
}
/* The same special case for ec_set */
else if ((what->aux & EAF_TYPE_MASK) == EAF_TYPE_EC_SET) {
res.type = T_ECLIST;
res.val.ad = adata_empty(f_pool, 0);
break;
}
/* Undefined value */
res.type = T_VOID;
break;
}
switch (what->aux & EAF_TYPE_MASK) {
case EAF_TYPE_INT:
res.type = T_INT;
res.val.i = e->u.data;
break;
case EAF_TYPE_ROUTER_ID:
res.type = T_QUAD;
res.val.i = e->u.data;
break;
case EAF_TYPE_OPAQUE:
res.type = T_ENUM_EMPTY;
res.val.i = 0;
break;
case EAF_TYPE_IP_ADDRESS:
res.type = T_IP;
struct adata * ad = e->u.ptr;
res.val.px.ip = * (ip_addr *) ad->data;
break;
case EAF_TYPE_AS_PATH:
res.type = T_PATH;
res.val.ad = e->u.ptr;
break;
case EAF_TYPE_INT_SET:
res.type = T_CLIST;
res.val.ad = e->u.ptr;
break;
case EAF_TYPE_EC_SET:
res.type = T_ECLIST;
res.val.ad = e->u.ptr;
break;
case EAF_TYPE_UNDEF:
res.type = T_VOID;
break;
default:
bug("Unknown type in e,a");
}
}
break;
case P('e','S'):
ONEARG;
{
struct ea_list *l = lp_alloc(f_pool, sizeof(struct ea_list) + sizeof(eattr));
l->next = NULL;
l->flags = EALF_SORTED;
l->count = 1;
l->attrs[0].id = what->a2.i;
l->attrs[0].flags = 0;
l->attrs[0].type = what->aux | EAF_ORIGINATED;
switch (what->aux & EAF_TYPE_MASK) {
case EAF_TYPE_INT:
if (v1.type != T_INT)
runtime( "Setting int attribute to non-int value" );
l->attrs[0].u.data = v1.val.i;
break;
case EAF_TYPE_ROUTER_ID:
#ifndef IPV6
/* IP->Quad implicit conversion */
if (v1.type == T_IP) {
l->attrs[0].u.data = ipa_to_u32(v1.val.px.ip);
break;
}
#endif
/* T_INT for backward compatibility */
if ((v1.type != T_QUAD) && (v1.type != T_INT))
runtime( "Setting quad attribute to non-quad value" );
l->attrs[0].u.data = v1.val.i;
break;
case EAF_TYPE_OPAQUE:
runtime( "Setting opaque attribute is not allowed" );
break;
case EAF_TYPE_IP_ADDRESS:
if (v1.type != T_IP)
runtime( "Setting ip attribute to non-ip value" );
int len = sizeof(ip_addr);
struct adata *ad = lp_alloc(f_pool, sizeof(struct adata) + len);
ad->length = len;
(* (ip_addr *) ad->data) = v1.val.px.ip;
l->attrs[0].u.ptr = ad;
break;
case EAF_TYPE_AS_PATH:
if (v1.type != T_PATH)
runtime( "Setting path attribute to non-path value" );
l->attrs[0].u.ptr = v1.val.ad;
break;
case EAF_TYPE_INT_SET:
if (v1.type != T_CLIST)
runtime( "Setting clist attribute to non-clist value" );
l->attrs[0].u.ptr = v1.val.ad;
break;
case EAF_TYPE_EC_SET:
if (v1.type != T_ECLIST)
runtime( "Setting eclist attribute to non-eclist value" );
l->attrs[0].u.ptr = v1.val.ad;
break;
case EAF_TYPE_UNDEF:
if (v1.type != T_VOID)
runtime( "Setting void attribute to non-void value" );
l->attrs[0].u.data = 0;
break;
default: bug("Unknown type in e,S");
}
if (!(what->aux & EAF_TEMP) && (!(f_flags & FF_FORCE_TMPATTR))) {
f_rta_cow();
l->next = (*f_rte)->attrs->eattrs;
(*f_rte)->attrs->eattrs = l;
} else {
l->next = (*f_tmp_attrs);
(*f_tmp_attrs) = l;
}
}
break;
case 'P':
res.type = T_INT;
res.val.i = (*f_rte)->pref;
break;
case P('P','S'):
ONEARG;
if (v1.type != T_INT)
runtime( "Can't set preference to non-integer" );
if ((v1.val.i < 0) || (v1.val.i > 0xFFFF))
runtime( "Setting preference value out of bounds" );
f_rte_cow();
(*f_rte)->pref = v1.val.i;
break;
case 'L': /* Get length of */
ONEARG;
res.type = T_INT;
switch(v1.type) {
case T_PREFIX: res.val.i = v1.val.px.len; break;
case T_PATH: res.val.i = as_path_getlen(v1.val.ad); break;
default: runtime( "Prefix or path expected" );
}
break;
case P('c','p'): /* Convert prefix to ... */
ONEARG;
if (v1.type != T_PREFIX)
runtime( "Prefix expected" );
res.type = what->aux;
switch(res.type) {
/* case T_INT: res.val.i = v1.val.px.len; break; Not needed any more */
case T_IP: res.val.px.ip = v1.val.px.ip; break;
default: bug( "Unknown prefix to conversion" );
}
break;
case P('a','f'): /* Get first ASN from AS PATH */
ONEARG;
if (v1.type != T_PATH)
runtime( "AS path expected" );
as = 0;
as_path_get_first(v1.val.ad, &as);
res.type = T_INT;
res.val.i = as;
break;
case P('a','l'): /* Get last ASN from AS PATH */
ONEARG;
if (v1.type != T_PATH)
runtime( "AS path expected" );
as = 0;
as_path_get_last(v1.val.ad, &as);
res.type = T_INT;
res.val.i = as;
break;
case 'r':
ONEARG;
res = v1;
res.type |= T_RETURN;
return res;
case P('c','a'): /* CALL: this is special: if T_RETURN and returning some value, mask it out */
ONEARG;
res = interpret(what->a2.p);
if (res.type == T_RETURN)
return res;
res.type &= ~T_RETURN;
break;
case P('c','v'): /* Clear local variables */
for (sym = what->a1.p; sym != NULL; sym = sym->aux2)
((struct f_val *) sym->def)->type = T_VOID;
break;
case P('S','W'):
ONEARG;
{
struct f_tree *t = find_tree(what->a2.p, v1);
if (!t) {
v1.type = T_VOID;
t = find_tree(what->a2.p, v1);
if (!t) {
debug( "No else statement?\n");
break;
}
}
/* It is actually possible to have t->data NULL */
res = interpret(t->data);
if (res.type & T_RETURN)
return res;
}
break;
case P('i','M'): /* IP.MASK(val) */
TWOARGS;
if (v2.type != T_INT)
runtime( "Integer expected");
if (v1.type != T_IP)
runtime( "You can mask only IP addresses" );
{
ip_addr mask = ipa_mkmask(v2.val.i);
res.type = T_IP;
res.val.px.ip = ipa_and(mask, v1.val.px.ip);
}
break;
case 'E': /* Create empty attribute */
res.type = what->aux;
res.val.ad = adata_empty(f_pool, 0);
break;
case P('A','p'): /* Path prepend */
TWOARGS;
if (v1.type != T_PATH)
runtime("Can't prepend to non-path");
if (v2.type != T_INT)
runtime("Can't prepend non-integer");
res.type = T_PATH;
res.val.ad = as_path_prepend(f_pool, v1.val.ad, v2.val.i);
break;
case P('C','a'): /* (Extended) Community list add or delete */
TWOARGS;
if (v1.type == T_CLIST)
{
/* Community (or cluster) list */
struct f_val dummy;
int arg_set = 0;
i = 0;
if ((v2.type == T_PAIR) || (v2.type == T_QUAD))
i = v2.val.i;
#ifndef IPV6
/* IP->Quad implicit conversion */
else if (v2.type == T_IP)
i = ipa_to_u32(v2.val.px.ip);
#endif
else if ((v2.type == T_SET) && clist_set_type(v2.val.t, &dummy))
arg_set = 1;
else if (v2.type == T_CLIST)
arg_set = 2;
else
runtime("Can't add/delete non-pair");
res.type = T_CLIST;
switch (what->aux)
{
case 'a':
if (arg_set == 1)
runtime("Can't add set");
else if (!arg_set)
res.val.ad = int_set_add(f_pool, v1.val.ad, i);
else
res.val.ad = int_set_union(f_pool, v1.val.ad, v2.val.ad);
break;
case 'd':
if (!arg_set)
res.val.ad = int_set_del(f_pool, v1.val.ad, i);
else
res.val.ad = clist_filter(f_pool, v1.val.ad, v2, 0);
break;
case 'f':
if (!arg_set)
runtime("Can't filter pair");
res.val.ad = clist_filter(f_pool, v1.val.ad, v2, 1);
break;
default:
bug("unknown Ca operation");
}
}
else if (v1.type == T_ECLIST)
{
/* Extended community list */
int arg_set = 0;
/* v2.val is either EC or EC-set */
if ((v2.type == T_SET) && eclist_set_type(v2.val.t))
arg_set = 1;
else if (v2.type == T_ECLIST)
arg_set = 2;
else if (v2.type != T_EC)
runtime("Can't add/delete non-pair");
res.type = T_ECLIST;
switch (what->aux)
{
case 'a':
if (arg_set == 1)
runtime("Can't add set");
else if (!arg_set)
res.val.ad = ec_set_add(f_pool, v1.val.ad, v2.val.ec);
else
res.val.ad = ec_set_union(f_pool, v1.val.ad, v2.val.ad);
break;
case 'd':
if (!arg_set)
res.val.ad = ec_set_del(f_pool, v1.val.ad, v2.val.ec);
else
res.val.ad = eclist_filter(f_pool, v1.val.ad, v2, 0);
break;
case 'f':
if (!arg_set)
runtime("Can't filter ec");
res.val.ad = eclist_filter(f_pool, v1.val.ad, v2, 1);
break;
default:
bug("unknown Ca operation");
}
}
else
runtime("Can't add/delete to non-(e)clist");
break;
case P('R','C'): /* ROA Check */
if (what->arg1)
{
TWOARGS;
if ((v1.type != T_PREFIX) || (v2.type != T_INT))
runtime("Invalid argument to roa_check()");
as = v2.val.i;
}
else
{
v1.val.px.ip = (*f_rte)->net->n.prefix;
v1.val.px.len = (*f_rte)->net->n.pxlen;
/* We ignore temporary attributes, probably not a problem here */
/* 0x02 is a value of BA_AS_PATH, we don't want to include BGP headers */
eattr *e = ea_find((*f_rte)->attrs->eattrs, EA_CODE(EAP_BGP, 0x02));
if (!e || e->type != EAF_TYPE_AS_PATH)
runtime("Missing AS_PATH attribute");
as_path_get_last(e->u.ptr, &as);
}
struct roa_table_config *rtc = ((struct f_inst_roa_check *) what)->rtc;
if (!rtc->table)
runtime("Missing ROA table");
res.type = T_ENUM_ROA;
res.val.i = roa_check(rtc->table, v1.val.px.ip, v1.val.px.len, as);
break;
default:
bug( "Unknown instruction %d (%c)", what->code, what->code & 0xff);
}
if (what->next)
return interpret(what->next);
return res;
}
#undef ARG
#define ARG(x,y) \
if (!i_same(f1->y, f2->y)) \
return 0;
#define ONEARG ARG(v1, a1.p)
#define TWOARGS ARG(v1, a1.p) \
ARG(v2, a2.p)
#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->code != f2->code)
return 0;
if (f1 == f2) /* It looks strange, but it is possible with call rewriting trickery */
return 1;
switch(f1->code) {
case ',': /* fall through */
case '+':
case '-':
case '*':
case '/':
case '|':
case '&':
case P('m','p'):
case P('m','c'):
case P('!','='):
case P('=','='):
case '<':
case P('<','='): TWOARGS; break;
case '!': ONEARG; break;
case '~': TWOARGS; break;
case P('d','e'): ONEARG; break;
case 's':
ARG(v2, a2.p);
{
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 'c':
switch (f1->aux) {
case T_PREFIX_SET:
if (!trie_same(f1->a2.p, f2->a2.p))
return 0;
break;
case T_SET:
if (!same_tree(f1->a2.p, f2->a2.p))
return 0;
break;
case T_STRING:
if (strcmp(f1->a2.p, f2->a2.p))
return 0;
break;
default:
A2_SAME;
}
break;
case 'C':
if (val_compare(* (struct f_val *) f1->a1.p, * (struct f_val *) f2->a1.p))
return 0;
break;
case 'V':
if (strcmp((char *) f1->a2.p, (char *) f2->a2.p))
return 0;
break;
case 'p': case 'L': ONEARG; break;
case '?': TWOARGS; break;
case '0': case 'E': break;
case P('p',','): ONEARG; A2_SAME; break;
case 'P':
case 'a': A2_SAME; break;
case P('e','a'): A2_SAME; break;
case P('P','S'):
case P('a','S'):
case P('e','S'): ONEARG; A2_SAME; break;
case 'r': ONEARG; break;
case P('c','p'): ONEARG; break;
case P('c','a'): /* Call rewriting trickery to avoid exponential behaviour */
ONEARG;
if (!i_same(f1->a2.p, f2->a2.p))
return 0;
f2->a2.p = f1->a2.p;
break;
case P('c','v'): break; /* internal instruction */
case P('S','W'): ONEARG; if (!same_tree(f1->a2.p, f2->a2.p)) return 0; break;
case P('i','M'): TWOARGS; break;
case P('A','p'): TWOARGS; break;
case P('C','a'): TWOARGS; break;
case P('a','f'):
case P('a','l'): ONEARG; break;
case P('R','C'):
TWOARGS;
/* Does not really make sense - ROA check resuls may change anyway */
if (strcmp(((struct f_inst_roa_check *) f1)->rtc->name,
((struct f_inst_roa_check *) f2)->rtc->name))
return 0;
break;
default:
bug( "Unknown instruction %d in same (%c)", f1->code, f1->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_attrs: temporary attributes, prepared by caller or generated by f_run()
* @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.
*/
int
f_run(struct filter *filter, struct rte **rte, struct ea_list **tmp_attrs, 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 );
f_rte = rte;
f_old_rta = NULL;
f_tmp_attrs = tmp_attrs;
f_pool = tmp_pool;
f_flags = flags;
log_reset();
struct f_val res = interpret(filter->root);
if (f_old_rta) {
/*
* Cached rta was modified and f_rte contains now an uncached one,
* sharing some part with the cached one. The cached rta should
* be freed (if rte was originally COW, f_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
* f_old_rta, and these may be freed during rta_free(f_old_rta).
* This is not the problem if rte was COW, because original rte
* also holds the same rta.
*/
if (!rte_cow)
(*f_rte)->attrs = rta_lookup((*f_rte)->attrs);
rta_free(f_old_rta);
}
if (res.type != T_RETURN) {
log( L_ERR "Filter %s did not return accept nor reject. Make up your mind", filter->name);
return F_ERROR;
}
DBG( "done (%d)\n", res.val.i );
return res.val.i;
}
int
f_eval_int(struct f_inst *expr)
{
/* Called independently in parse-time to eval expressions */
struct f_val res;
f_flags = 0;
f_tmp_attrs = NULL;
f_rte = NULL;
f_pool = cfg_mem;
log_reset();
res = interpret(expr);
if (res.type != T_INT)
cf_error("Integer expression expected");
return res.val.i;
}
u32
f_eval_asn(struct f_inst *expr)
{
/* Called as a part of another interpret call, therefore no log_reset() */
struct f_val res = interpret(expr);
return (res.type == T_INT) ? res.val.i : 0;
}
/**
* 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);
}
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