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bird/filter/filter.c
Ondrej Zajicek 8d9eef1771 BGP multipath support 
Kernel option 'merge paths' allows to merge routes exported to kernel
protocol (currently BGP and static routes) to multipath routes.
2015-06-08 02:24:08 +02:00

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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 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;
case PM_ASN_EXPR:
buffer_print(buf, "%u ", f_eval_asn((struct f_inst *) p->val));
break;
}
p = p->next;
}
buffer_puts(buf, "=]");
}
static inline int
uint_cmp(uint i1, uint i2)
{
return (int)(i1 > i2) - (int)(i1 < i2);
}
static inline int
u64_cmp(u64 i1, u64 i2)
{
return (int)(i1 > i2) - (int)(i1 < i2);
}
/**
* val_compare - compare two values
* @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)
{
int rc;
if (v1.type != v2.type) {
if (v1.type == T_VOID) /* Hack for else */
return -1;
if (v2.type == T_VOID)
return 1;
#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_VOID:
return 0;
case T_ENUM:
case T_INT:
case T_BOOL:
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;
return uint_cmp(v1.val.px.len, v2.val.px.len);
case T_STRING:
return strcmp(v1.val.s, v2.val.s);
default:
return CMP_ERROR;
}
}
static int
pm_path_same(struct f_path_mask *m1, struct f_path_mask *m2)
{
while (m1 && m2)
{
if ((m1->kind != m2->kind) || (m1->val != m2->val))
return 0;
m1 = m1->next;
m2 = m2->next;
}
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_path_same(v1.val.path_mask, v2.val.path_mask);
case T_PATH:
case T_CLIST:
case T_ECLIST:
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);
}
}
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);
}
}
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.
*/
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);
#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);
if ((v1.type == T_PREFIX) && (v2.type == T_PREFIX_SET))
return trie_match_fprefix(v2.val.ti, &v1.val.px);
if (v2.type != T_SET)
return CMP_ERROR;
/* With integrated Quad<->IP implicit conversion */
if ((v1.type == v2.val.t->from.type) ||
((IP_VERSION == 4) && (v1.type == T_QUAD) && (v2.val.t->from.type == T_IP)))
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)
return eclist_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;
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.px.ip); return;
case T_PREFIX: buffer_print(buf, "%I/%d", v.val.px.ip, v.val.px.len); return;
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_PREFIX_SET: trie_format(v.val.ti, buf); return;
case T_SET: tree_format(v.val.t, buf); return;
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_PATH_MASK: pm_format(v.val.path_mask, buf); return;
default: buffer_print(buf, "[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 struct buffer f_buf;
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 (!rta_is_cached((*f_rte)->attrs))
return;
/* Prepare to modify rte */
f_rte_cow();
/* Store old rta to free it later, it stores reference from rte_cow() */
f_old_rta = (*f_rte)->attrs;
/*
* Get shallow copy of rta. 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).
*/
(*f_rte)->attrs = rta_do_cow((*f_rte)->attrs, f_pool);
}
static struct tbf rl_runtime_err = TBF_DEFAULT_LOG_LIMITS;
#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" );
#define ACCESS_RTE \
do { if (!f_rte) runtime("No route to access"); } while (0)
#define BITFIELD_MASK(what) \
(1u << (what->a2.i >> 24))
/**
* 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;
#define SAME(x) \
TWOARGS; \
i = val_same(v1, v2); \
res.type = T_BOOL; \
res.val.i = (x); \
break;
case P('!','='): SAME(!i);
case P('=','='): SAME(i);
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_format(v1, &f_buf);
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, &f_buf);
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 */
{
ACCESS_RTE;
struct rta *rta = (*f_rte)->attrs;
res.type = what->aux;
switch (what->a2.i)
{
case SA_FROM: res.val.px.ip = rta->from; break;
case SA_GW: res.val.px.ip = rta->gw; break;
case SA_NET: res.val.px.ip = (*f_rte)->net->n.prefix;
res.val.px.len = (*f_rte)->net->n.pxlen; break;
case SA_PROTO: res.val.s = rta->src->proto->name; break;
case SA_SOURCE: res.val.i = rta->source; break;
case SA_SCOPE: res.val.i = rta->scope; break;
case SA_CAST: res.val.i = rta->cast; break;
case SA_DEST: res.val.i = rta->dest; break;
case SA_IFNAME: res.val.s = rta->iface ? rta->iface->name : ""; break;
case SA_IFINDEX: res.val.i = rta->iface ? rta->iface->index : 0; break;
default:
bug("Invalid static attribute access (%x)", res.type);
}
}
break;
case P('a','S'):
ACCESS_RTE;
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->a2.i)
{
case SA_FROM:
rta->from = v1.val.px.ip;
break;
case SA_GW:
{
ip_addr ip = v1.val.px.ip;
neighbor *n = neigh_find(rta->src->proto, &ip, 0);
if (!n || (n->scope == SCOPE_HOST))
runtime( "Invalid gw address" );
rta->dest = RTD_ROUTER;
rta->gw = ip;
rta->iface = n->iface;
rta->nexthops = NULL;
rta->hostentry = NULL;
}
break;
case SA_SCOPE:
rta->scope = v1.val.i;
break;
case SA_DEST:
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;
rta->hostentry = NULL;
break;
default:
bug("Invalid static attribute access (%x)", res.type);
}
}
break;
case P('e','a'): /* Access to extended attributes */
ACCESS_RTE;
{
eattr *e = NULL;
u16 code = what->a2.i;
if (!(f_flags & FF_FORCE_TMPATTR))
e = ea_find((*f_rte)->attrs->eattrs, code);
if (!e)
e = ea_find((*f_tmp_attrs), code);
if ((!e) && (f_flags & FF_FORCE_TMPATTR))
e = ea_find((*f_rte)->attrs->eattrs, code);
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 */
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_BITFIELD:
res.type = T_BOOL;
res.val.i = !!(e->u.data & BITFIELD_MASK(what));
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'):
ACCESS_RTE;
ONEARG;
{
struct ea_list *l = lp_alloc(f_pool, sizeof(struct ea_list) + sizeof(eattr));
u16 code = what->a2.i;
l->next = NULL;
l->flags = EALF_SORTED;
l->count = 1;
l->attrs[0].id = code;
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_BITFIELD:
if (v1.type != T_BOOL)
runtime( "Setting bit in bitfield attribute to non-bool value" );
{
/* First, we have to find the old value */
eattr *e = NULL;
if (!(f_flags & FF_FORCE_TMPATTR))
e = ea_find((*f_rte)->attrs->eattrs, code);
if (!e)
e = ea_find((*f_tmp_attrs), code);
if ((!e) && (f_flags & FF_FORCE_TMPATTR))
e = ea_find((*f_rte)->attrs->eattrs, code);
u32 data = e ? e->u.data : 0;
if (v1.val.i)
l->attrs[0].u.data = data | BITFIELD_MASK(what);
else
l->attrs[0].u.data = data & ~BITFIELD_MASK(what);;
}
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':
ACCESS_RTE;
res.type = T_INT;
res.val.i = (*f_rte)->pref;
break;
case P('P','S'):
ACCESS_RTE;
ONEARG;
if (v1.type != T_INT)
runtime( "Can't set preference to non-integer" );
if (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;
case T_CLIST: res.val.i = int_set_get_size(v1.val.ad); break;
case T_ECLIST: res.val.i = ec_set_get_size(v1.val.ad); break;
default: runtime( "Prefix, path, clist or eclist 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_PATH)
{
struct f_tree *set = NULL;
u32 key = 0;
int pos;
if (v2.type == T_INT)
key = v2.val.i;
else if ((v2.type == T_SET) && (v2.val.t->from.type == T_INT))
set = v2.val.t;
else
runtime("Can't delete non-integer (set)");
switch (what->aux)
{
case 'a': runtime("Can't add to path");
case 'd': pos = 0; break;
case 'f': pos = 1; break;
default: bug("unknown Ca operation");
}
if (pos && !set)
runtime("Can't filter integer");
res.type = T_PATH;
res.val.ad = as_path_filter(f_pool, v1.val.ad, set, key, pos);
}
else if (v1.type == T_CLIST)
{
/* Community (or cluster) list */
struct f_val dummy;
int arg_set = 0;
uint n = 0;
if ((v2.type == T_PAIR) || (v2.type == T_QUAD))
n = v2.val.i;
#ifndef IPV6
/* IP->Quad implicit conversion */
else if (v2.type == T_IP)
n = 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, n);
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, n);
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
{
ACCESS_RTE;
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_same(* (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_BUFFER_INIT(f_buf);
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_rl(&rl_runtime_err, L_ERR "Filter %s did not return accept nor reject. Make up your mind", filter->name);
return F_ERROR;
}
DBG( "done (%u)\n", res.val.i );
return res.val.i;
}
struct f_val
f_eval(struct f_inst *expr, struct linpool *tmp_pool)
{
f_flags = 0;
f_tmp_attrs = NULL;
f_rte = NULL;
f_pool = tmp_pool;
LOG_BUFFER_INIT(f_buf);
return interpret(expr);
}
uint
f_eval_int(struct f_inst *expr)
{
/* Called independently in parse-time to eval expressions */
struct f_val res = f_eval(expr, cfg_mem);
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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