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rde_attr.c
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/* $OpenBSD$ */
/*
* Copyright (c) 2004 Claudio Jeker <[email protected]>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/types.h>
#include <sys/hash.h>
#include <sys/queue.h>
#include <netinet/in.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "bgpd.h"
#include "rde.h"
int
attr_write(void *p, u_int16_t p_len, u_int8_t flags, u_int8_t type,
void *data, u_int16_t data_len)
{
u_char *b = p;
u_int16_t tmp, tot_len = 2; /* attribute header (without len) */
if (data_len > 255) {
tot_len += 2 + data_len;
flags |= ATTR_EXTLEN;
} else {
tot_len += 1 + data_len;
flags &= ~ATTR_EXTLEN;
}
if (tot_len > p_len)
return (-1);
*b++ = flags;
*b++ = type;
if (data_len > 255) {
tmp = htons(data_len);
memcpy(b, &tmp, sizeof(tmp));
b += 2;
} else
*b++ = (u_char)data_len;
if (data_len != 0)
memcpy(b, data, data_len);
return (tot_len);
}
int
attr_writebuf(struct buf *buf, u_int8_t flags, u_int8_t type, void *data,
u_int16_t data_len)
{
u_char hdr[4];
if (data_len > 255) {
flags |= ATTR_EXTLEN;
hdr[2] = (data_len >> 8) & 0xff;
hdr[3] = data_len & 0xff;
} else {
flags &= ~ATTR_EXTLEN;
hdr[2] = data_len & 0xff;
}
hdr[0] = flags;
hdr[1] = type;
if (buf_add(buf, hdr, flags & ATTR_EXTLEN ? 4 : 3) == -1)
return (-1);
if (buf_add(buf, data, data_len) == -1)
return (-1);
return (0);
}
/* optional attribute specific functions */
int attr_diff(struct attr *, struct attr *);
struct attr *attr_alloc(u_int8_t, u_int8_t, const void *, u_int16_t);
struct attr *attr_lookup(u_int8_t, u_int8_t, const void *, u_int16_t);
void attr_put(struct attr *);
struct attr_table {
struct attr_list *hashtbl;
u_int32_t hashmask;
} attrtable;
#define ATTR_HASH(x) \
&attrtable.hashtbl[(x) & attrtable.hashmask]
void
attr_init(u_int32_t hashsize)
{
u_int32_t hs, i;
for (hs = 1; hs < hashsize; hs <<= 1)
;
attrtable.hashtbl = calloc(hs, sizeof(struct attr_list));
if (attrtable.hashtbl == NULL)
fatal("attr_init");
for (i = 0; i < hs; i++)
LIST_INIT(&attrtable.hashtbl[i]);
attrtable.hashmask = hs - 1;
}
void
attr_shutdown(void)
{
u_int32_t i;
for (i = 0; i <= attrtable.hashmask; i++)
if (!LIST_EMPTY(&attrtable.hashtbl[i]))
log_warnx("attr_shutdown: free non-free table");
free(attrtable.hashtbl);
}
int
attr_optadd(struct rde_aspath *asp, u_int8_t flags, u_int8_t type,
void *data, u_int16_t len)
{
u_int8_t l;
struct attr *a, *t;
void *p;
/* known optional attributes were validated previously */
if ((a = attr_lookup(flags, type, data, len)) == NULL)
a = attr_alloc(flags, type, data, len);
/* attribute allowed only once */
for (l = 0; l < asp->others_len; l++) {
if (asp->others[l] == NULL)
break;
if (type == asp->others[l]->type)
return (-1);
}
/* add attribute to the table but first bump refcnt */
a->refcnt++;
rdemem.attr_refs++;
for (l = 0; l < asp->others_len; l++) {
if (asp->others[l] == NULL) {
asp->others[l] = a;
return (0);
}
/* list is sorted */
if (a->type < asp->others[l]->type) {
t = asp->others[l];
asp->others[l] = a;
a = t;
}
}
/* no empty slot found, need to realloc */
if (asp->others_len == UCHAR_MAX)
fatalx("attr_optadd: others_len overflow");
asp->others_len++;
if ((p = realloc(asp->others,
asp->others_len * sizeof(struct attr *))) == NULL)
fatal("attr_optadd");
asp->others = p;
/* l stores the size of others before resize */
asp->others[l] = a;
return (0);
}
struct attr *
attr_optget(const struct rde_aspath *asp, u_int8_t type)
{
u_int8_t l;
for (l = 0; l < asp->others_len; l++) {
if (asp->others[l] == NULL)
break;
if (type == asp->others[l]->type)
return (asp->others[l]);
if (type < asp->others[l]->type)
break;
}
return (NULL);
}
void
attr_copy(struct rde_aspath *t, struct rde_aspath *s)
{
u_int8_t l;
if (t->others != NULL)
attr_freeall(t);
t->others_len = s->others_len;
if (t->others_len == 0) {
t->others = NULL;
return;
}
if ((t->others = calloc(s->others_len, sizeof(struct attr *))) == 0)
fatal("attr_copy");
for (l = 0; l < t->others_len; l++) {
if (s->others[l] == NULL)
break;
s->others[l]->refcnt++;
rdemem.attr_refs++;
t->others[l] = s->others[l];
}
}
int
attr_diff(struct attr *oa, struct attr *ob)
{
int r;
if (ob == NULL)
return (1);
if (oa == NULL)
return (-1);
if (oa->flags > ob->flags)
return (1);
if (oa->flags < ob->flags)
return (-1);
if (oa->type > ob->type)
return (1);
if (oa->type < ob->type)
return (-1);
if (oa->len > ob->len)
return (1);
if (oa->len < ob->len)
return (-1);
r = memcmp(oa->data, ob->data, oa->len);
if (r > 0)
return (1);
if (r < 0)
return (-1);
fatalx("attr_diff: equal attributes encountered");
return (0);
}
int
attr_compare(struct rde_aspath *a, struct rde_aspath *b)
{
u_int8_t l, min;
min = a->others_len < b->others_len ? a->others_len : b->others_len;
for (l = 0; l < min; l++)
if (a->others[l] != b->others[l])
return (attr_diff(a->others[l], b->others[l]));
if (a->others_len < b->others_len) {
for (; l < b->others_len; l++)
if (b->others[l] != NULL)
return (-1);
} else if (a->others_len > b->others_len) {
for (; l < a->others_len; l++)
if (a->others[l] != NULL)
return (1);
}
return (0);
}
void
attr_free(struct rde_aspath *asp, struct attr *attr)
{
u_int8_t l;
for (l = 0; l < asp->others_len; l++)
if (asp->others[l] == attr) {
attr_put(asp->others[l]);
for (++l; l < asp->others_len; l++)
asp->others[l - 1] = asp->others[l];
asp->others[asp->others_len - 1] = NULL;
return;
}
/* no realloc() because the slot may be reused soon */
}
void
attr_freeall(struct rde_aspath *asp)
{
u_int8_t l;
for (l = 0; l < asp->others_len; l++)
attr_put(asp->others[l]);
free(asp->others);
asp->others = NULL;
asp->others_len = 0;
}
struct attr *
attr_alloc(u_int8_t flags, u_int8_t type, const void *data, u_int16_t len)
{
struct attr *a;
a = calloc(1, sizeof(struct attr));
if (a == NULL)
fatal("attr_optadd");
rdemem.attr_cnt++;
a->flags = flags;
a->hash = hash32_buf(&flags, sizeof(flags), HASHINIT);
a->type = type;
a->hash = hash32_buf(&type, sizeof(type), a->hash);
a->len = len;
if (len != 0) {
if ((a->data = malloc(len)) == NULL)
fatal("attr_optadd");
rdemem.attr_dcnt++;
rdemem.attr_data += len;
memcpy(a->data, data, len);
} else
a->data = NULL;
a->hash = hash32_buf(&len, sizeof(len), a->hash);
a->hash = hash32_buf(a->data, a->len, a->hash);
LIST_INSERT_HEAD(ATTR_HASH(a->hash), a, entry);
return (a);
}
struct attr *
attr_lookup(u_int8_t flags, u_int8_t type, const void *data, u_int16_t len)
{
struct attr_list *head;
struct attr *a;
u_int32_t hash;
hash = hash32_buf(&flags, sizeof(flags), HASHINIT);
hash = hash32_buf(&type, sizeof(type), hash);
hash = hash32_buf(&len, sizeof(len), hash);
hash = hash32_buf(data, len, hash);
head = ATTR_HASH(hash);
LIST_FOREACH(a, head, entry) {
if (hash == a->hash && type == a->type &&
flags == a->flags && len == a->len &&
memcmp(data, a->data, len) == 0)
return (a);
}
return (NULL);
}
void
attr_put(struct attr *a)
{
if (a == NULL)
return;
rdemem.attr_refs--;
if (--a->refcnt > 0)
/* somebody still holds a reference */
return;
/* unlink */
LIST_REMOVE(a, entry);
if (a->len != 0)
rdemem.attr_dcnt--;
rdemem.attr_data -= a->len;
rdemem.attr_cnt--;
free(a->data);
free(a);
}
/* aspath specific functions */
u_int16_t aspath_countlength(struct aspath *, u_int16_t, int);
void aspath_countcopy(struct aspath *, u_int16_t, u_int8_t *,
u_int16_t, int);
struct aspath *aspath_lookup(const void *, u_int16_t);
struct aspath_table {
struct aspath_list *hashtbl;
u_int32_t hashmask;
} astable;
#define ASPATH_HASH(x) \
&astable.hashtbl[(x) & astable.hashmask]
int
aspath_verify(void *data, u_int16_t len, int as4byte)
{
u_int8_t *seg = data;
u_int16_t seg_size, as_size = 2;
u_int8_t seg_len, seg_type;
if (len & 1)
/* odd length aspath are invalid */
return (AS_ERR_BAD);
if (as4byte)
as_size = 4;
for (; len > 0; len -= seg_size, seg += seg_size) {
if (len < 2) /* header length check */
return (AS_ERR_BAD);
seg_type = seg[0];
seg_len = seg[1];
if (seg_type != AS_SET && seg_type != AS_SEQUENCE)
return (AS_ERR_TYPE);
seg_size = 2 + as_size * seg_len;
if (seg_size > len)
return (AS_ERR_LEN);
if (seg_size == 0)
/* empty aspath segments are not allowed */
return (AS_ERR_BAD);
}
return (0); /* aspath is valid but probably not loop free */
}
void
aspath_init(u_int32_t hashsize)
{
u_int32_t hs, i;
for (hs = 1; hs < hashsize; hs <<= 1)
;
astable.hashtbl = calloc(hs, sizeof(struct aspath_list));
if (astable.hashtbl == NULL)
fatal("aspath_init");
for (i = 0; i < hs; i++)
LIST_INIT(&astable.hashtbl[i]);
astable.hashmask = hs - 1;
}
void
aspath_shutdown(void)
{
u_int32_t i;
for (i = 0; i <= astable.hashmask; i++)
if (!LIST_EMPTY(&astable.hashtbl[i]))
log_warnx("aspath_shutdown: free non-free table");
free(astable.hashtbl);
}
struct aspath *
aspath_get(void *data, u_int16_t len)
{
struct aspath_list *head;
struct aspath *aspath;
/* The aspath must already have been checked for correctness. */
aspath = aspath_lookup(data, len);
if (aspath == NULL) {
aspath = malloc(ASPATH_HEADER_SIZE + len);
if (aspath == NULL)
fatal("aspath_get");
rdemem.aspath_cnt++;
rdemem.aspath_size += ASPATH_HEADER_SIZE + len;
aspath->refcnt = 0;
aspath->len = len;
aspath->ascnt = aspath_count(data, len);
memcpy(aspath->data, data, len);
/* link */
head = ASPATH_HASH(hash32_buf(aspath->data, aspath->len,
HASHINIT));
LIST_INSERT_HEAD(head, aspath, entry);
}
aspath->refcnt++;
rdemem.aspath_refs++;
return (aspath);
}
void
aspath_put(struct aspath *aspath)
{
if (aspath == NULL)
return;
rdemem.aspath_refs--;
if (--aspath->refcnt > 0) {
/* somebody still holds a reference */
return;
}
/* unlink */
LIST_REMOVE(aspath, entry);
rdemem.aspath_cnt--;
rdemem.aspath_size -= ASPATH_HEADER_SIZE + aspath->len;
free(aspath);
}
u_char *
aspath_inflate(void *data, u_int16_t len, u_int16_t *newlen)
{
u_int8_t *seg, *nseg, *ndata;
u_int16_t seg_size, olen, nlen;
u_int8_t seg_len;
/* first calculate the length of the aspath */
seg = data;
nlen = 0;
for (olen = len; olen > 0; olen -= seg_size, seg += seg_size) {
seg_len = seg[1];
seg_size = 2 + sizeof(u_int16_t) * seg_len;
nlen += 2 + sizeof(u_int32_t) * seg_len;
if (seg_size > olen)
fatalx("aspath_inflate: would overflow");
}
*newlen = nlen;
if ((ndata = malloc(nlen)) == NULL)
fatal("aspath_inflate");
/* then copy the aspath */
seg = data;
for (nseg = ndata; nseg < ndata + nlen; ) {
*nseg++ = *seg++;
*nseg++ = seg_len = *seg++;
for (; seg_len > 0; seg_len--) {
*nseg++ = 0;
*nseg++ = 0;
*nseg++ = *seg++;
*nseg++ = *seg++;
}
}
return (ndata);
}
/* convert a 4 byte aspath to a 2byte one. data is freed by aspath_deflate */
u_char *
aspath_deflate(u_char *data, u_int16_t *len, int *flagnew)
{
u_int8_t *seg, *nseg, *ndata;
u_int32_t as;
int i;
u_int16_t seg_size, olen, nlen;
u_int8_t seg_len;
/* first calculate the length of the aspath */
nlen = 0;
seg = data;
olen = *len;
for (; olen > 0; olen -= seg_size, seg += seg_size) {
seg_len = seg[1];
seg_size = 2 + sizeof(u_int32_t) * seg_len;
nlen += 2 + sizeof(u_int16_t) * seg_len;
if (seg_size > olen)
fatalx("aspath_deflate: would overflow");
}
if ((ndata = malloc(nlen)) == NULL)
fatal("aspath_deflate");
/* then copy the aspath */
seg = data;
olen = *len;
for (nseg = ndata; seg < data + olen; seg += seg_size) {
*nseg++ = seg[0];
*nseg++ = seg_len = seg[1];
seg_size = 2 + sizeof(u_int32_t) * seg_len;
for (i = 0; i < seg_len; i++) {
as = aspath_extract(seg, i);
if (as > USHRT_MAX) {
as = AS_TRANS;
*flagnew = 1;
}
*nseg++ = (as >> 8) & 0xff;
*nseg++ = as & 0xff;
}
}
free(data);
*len = nlen;
return (ndata);
}
void
aspath_merge(struct rde_aspath *a, struct attr *attr)
{
u_int8_t *np;
u_int16_t ascnt, diff, nlen, difflen;
int hroom = 0;
ascnt = aspath_count(attr->data, attr->len);
if (ascnt > a->aspath->ascnt) {
/* ASPATH is shorter then AS4_PATH no way to merge */
attr_free(a, attr);
return;
}
diff = a->aspath->ascnt - ascnt;
if (diff && attr->len > 2 && attr->data[0] == AS_SEQUENCE)
hroom = attr->data[1];
difflen = aspath_countlength(a->aspath, diff, hroom);
nlen = attr->len + difflen;
if ((np = malloc(nlen)) == NULL)
fatal("aspath_merge");
/* copy head from old aspath */
aspath_countcopy(a->aspath, diff, np, difflen, hroom);
/* copy tail from new aspath */
if (hroom > 0)
memcpy(np + nlen - attr->len + 2, attr->data + 2,
attr->len - 2);
else
memcpy(np + nlen - attr->len, attr->data, attr->len);
aspath_put(a->aspath);
a->aspath = aspath_get(np, nlen);
free(np);
attr_free(a, attr);
}
u_char *
aspath_dump(struct aspath *aspath)
{
return (aspath->data);
}
u_int16_t
aspath_length(struct aspath *aspath)
{
return (aspath->len);
}
u_int16_t
aspath_count(const void *data, u_int16_t len)
{
const u_int8_t *seg;
u_int16_t cnt, seg_size;
u_int8_t seg_type, seg_len;
cnt = 0;
seg = data;
for (; len > 0; len -= seg_size, seg += seg_size) {
seg_type = seg[0];
seg_len = seg[1];
seg_size = 2 + sizeof(u_int32_t) * seg_len;
if (seg_type == AS_SET)
cnt += 1;
else
cnt += seg_len;
if (seg_size > len)
fatalx("aspath_count: would overflow");
}
return (cnt);
}
u_int16_t
aspath_countlength(struct aspath *aspath, u_int16_t cnt, int headcnt)
{
const u_int8_t *seg;
u_int16_t seg_size, len, clen;
u_int8_t seg_type = 0, seg_len = 0;
seg = aspath->data;
clen = 0;
for (len = aspath->len; len > 0 && cnt > 0;
len -= seg_size, seg += seg_size) {
seg_type = seg[0];
seg_len = seg[1];
seg_size = 2 + sizeof(u_int32_t) * seg_len;
if (seg_type == AS_SET)
cnt -= 1;
else if (seg_len > cnt) {
seg_len = cnt;
clen += 2 + sizeof(u_int32_t) * cnt;
break;
} else
cnt -= seg_len;
clen += seg_size;
if (seg_size > len)
fatalx("aspath_countlength: would overflow");
}
if (headcnt > 0 && seg_type == AS_SEQUENCE && headcnt + seg_len < 256)
/* no need for additional header from the new aspath. */
clen -= 2;
return (clen);
}
void
aspath_countcopy(struct aspath *aspath, u_int16_t cnt, u_int8_t *buf,
u_int16_t size, int headcnt)
{
const u_int8_t *seg;
u_int16_t seg_size, len;
u_int8_t seg_type, seg_len;
if (headcnt > 0)
/*
* additional room because we steal the segment header
* from the other aspath
*/
size += 2;
seg = aspath->data;
for (len = aspath->len; len > 0 && cnt > 0;
len -= seg_size, seg += seg_size) {
seg_type = seg[0];
seg_len = seg[1];
seg_size = 2 + sizeof(u_int32_t) * seg_len;
if (seg_type == AS_SET)
cnt -= 1;
else if (seg_len > cnt) {
seg_len = cnt + headcnt;
seg_size = 2 + sizeof(u_int32_t) * cnt;
cnt = 0;
} else {
cnt -= seg_len;
if (cnt == 0)
seg_len += headcnt;
}
memcpy(buf, seg, seg_size);
buf[0] = seg_type;
buf[1] = seg_len;
buf += seg_size;
if (size < seg_size)
fatalx("aspath_countlength: would overflow");
size -= seg_size;
}
}
u_int32_t
aspath_neighbor(struct aspath *aspath)
{
/*
* Empty aspath is OK -- internal as route.
* But what is the neighbor? For now let's return 0.
* That should not break anything.
*/
if (aspath->len == 0)
return (0);
return (aspath_extract(aspath->data, 0));
}
int
aspath_loopfree(struct aspath *aspath, u_int32_t myAS)
{
u_int8_t *seg;
u_int16_t len, seg_size;
u_int8_t i, seg_len, seg_type;
seg = aspath->data;
for (len = aspath->len; len > 0; len -= seg_size, seg += seg_size) {
seg_type = seg[0];
seg_len = seg[1];
seg_size = 2 + sizeof(u_int32_t) * seg_len;
for (i = 0; i < seg_len; i++) {
if (myAS == aspath_extract(seg, i))
return (0);
}
if (seg_size > len)
fatalx("aspath_loopfree: would overflow");
}
return (1);
}
int
aspath_compare(struct aspath *a1, struct aspath *a2)
{
int r;
if (a1->len > a2->len)
return (1);
if (a1->len < a2->len)
return (-1);
r = memcmp(a1->data, a2->data, a1->len);
if (r > 0)
return (1);
if (r < 0)
return (-1);
return (0);
}
struct aspath *
aspath_lookup(const void *data, u_int16_t len)
{
struct aspath_list *head;
struct aspath *aspath;
u_int32_t hash;
hash = hash32_buf(data, len, HASHINIT);
head = ASPATH_HASH(hash);
LIST_FOREACH(aspath, head, entry) {
if (len == aspath->len && memcmp(data, aspath->data, len) == 0)
return (aspath);
}
return (NULL);
}
/*
* Returns a new prepended aspath. Old needs to be freed by caller.
*/
u_char *
aspath_prepend(struct aspath *asp, u_int32_t as, int quantum, u_int16_t *len)
{
u_char *p;
int l, overflow = 0, shift = 0, size, wpos = 0;
u_int8_t type;
/* lunatic prepends are blocked in the parser and limited */
/* first calculate new size */
if (asp->len > 0) {
if (asp->len < 2)
fatalx("aspath_prepend: bad aspath length");
type = asp->data[0];
size = asp->data[1];
} else {
/* empty as path */
type = AS_SET;
size = 0;
}
if (quantum > 255)
fatalx("aspath_prepend: preposterous prepend");
if (quantum == 0) {
/* no change needed but return a copy */
p = malloc(asp->len);
if (p == NULL)
fatal("aspath_prepend");
memcpy(p, asp->data, asp->len);
*len = asp->len;
return (p);
} else if (type == AS_SET || size + quantum > 255) {
/* need to attach a new AS_SEQUENCE */
l = 2 + quantum * sizeof(u_int32_t) + asp->len;
if (type == AS_SET)
overflow = quantum;
else
overflow = size + quantum - 255;
} else
l = quantum * sizeof(u_int32_t) + asp->len;
quantum -= overflow;
p = malloc(l);
if (p == NULL)
fatal("aspath_prepend");
/* first prepends */
as = htonl(as);
if (overflow > 0) {
p[wpos++] = AS_SEQUENCE;
p[wpos++] = overflow;
for (; overflow > 0; overflow--) {
memcpy(p + wpos, &as, sizeof(u_int32_t));
wpos += sizeof(u_int32_t);
}
}
if (quantum > 0) {
shift = 2;
p[wpos++] = AS_SEQUENCE;
p[wpos++] = quantum + size;
for (; quantum > 0; quantum--) {
memcpy(p + wpos, &as, sizeof(u_int32_t));
wpos += sizeof(u_int32_t);
}
}
memcpy(p + wpos, asp->data + shift, asp->len - shift);
*len = l;
return (p);
}
/* we need to be able to search more than one as */
int
aspath_match(struct aspath *a, enum as_spec type, u_int32_t as)
{
u_int8_t *seg;
int final;
u_int16_t len, seg_size;
u_int8_t i, seg_type, seg_len;
if (type == AS_EMPTY) {
if (a->len == 0)
return (1);
else
return (0);
}
final = 0;
seg = a->data;
for (len = a->len; len > 0; len -= seg_size, seg += seg_size) {
seg_type = seg[0];
seg_len = seg[1];
seg_size = 2 + sizeof(u_int32_t) * seg_len;
final = (len == seg_size);
/* just check the first (leftmost) AS */
if (type == AS_PEER) {
if (as == aspath_extract(seg, 0))
return (1);
else
return (0);
}
/* just check the final (rightmost) AS */
if (type == AS_SOURCE) {
/* not yet in the final segment */
if (!final)
continue;
if (as == aspath_extract(seg, seg_len - 1))
return (1);
else
return (0);
}
/* AS_TRANSIT or AS_ALL */
for (i = 0; i < seg_len; i++) {
if (as == aspath_extract(seg, i)) {
/*
* the source (rightmost) AS is excluded from
* AS_TRANSIT matches.
*/
if (final && i == seg_len - 1 &&
type == AS_TRANSIT)
return (0);
return (1);
}
}
}
return (0);
}
/*
* Functions handling communities and extended communities.
*/
int community_ext_conv(struct filter_extcommunity *, u_int16_t, u_int64_t *);
int
community_match(struct rde_aspath *asp, int as, int type)
{
struct attr *a;
u_int8_t *p;
u_int16_t eas, etype, len;
a = attr_optget(asp, ATTR_COMMUNITIES);
if (a == NULL)
/* no communities, no match */
return (0);
len = a->len / 4;
p = a->data;
for (; len > 0; len--) {
eas = *p++;
eas <<= 8;
eas |= *p++;
etype = *p++;
etype <<= 8;