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Better handling of too long attributes

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This patch extends the length for attributes from 1024 to 2048
(because both AS_PATH and AS4_PATH attributes take 2+4 B per AS).

If there is not enough space for attributes, Bird skips that
route group. Old behavior (skipping remaining attributes)
leads to skipping required attributes and session drop.
This commit is contained in:
Ondrej Zajicek 2009-02-27 15:24:46 +01:00
parent cb53039271
commit 82a79586e5
2 changed files with 44 additions and 8 deletions
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5
proto/bgp/attrs.c
View file

@ -347,7 +347,7 @@ bgp_get_attr_len(eattr *a)
* The bgp_encode_attrs() function takes a list of extended attributes
* and converts it to its BGP representation (a part of an Update message).
*
* Result: Length of the attribute block generated.
* Result: Length of the attribute block generated or -1 if not enough space.
*/
unsigned int
bgp_encode_attrs(struct bgp_proto *p, byte *w, ea_list *attrs, int remains)
@ -488,8 +488,7 @@ bgp_encode_attrs(struct bgp_proto *p, byte *w, ea_list *attrs, int remains)
return w - start;
err_no_buffer:
log(L_ERR "BGP: attribute list too long, ignoring the remaining attributes");
return w - start;
return -1;
}
static void

47
proto/bgp/packets.c
View file

@ -127,6 +127,18 @@ bgp_encode_prefixes(struct bgp_proto *p, byte *w, struct bgp_bucket *buck, unsig
return w - start;
}
static void
bgp_flush_prefixes(struct bgp_proto *p, struct bgp_bucket *buck)
{
while (!EMPTY_LIST(buck->prefixes))
{
struct bgp_prefix *px = SKIP_BACK(struct bgp_prefix, bucket_node, HEAD(buck->prefixes));
log(L_ERR "%s: - route %I/%d skipped", p->p.name, px->n.prefix, px->n.pxlen);
rem_node(&px->bucket_node);
fib_delete(&p->prefix_fib, px);
}
}
#ifndef IPV6 /* IPv4 version */
static byte *
@ -150,7 +162,7 @@ bgp_create_update(struct bgp_conn *conn, byte *buf)
}
put_u16(buf, wd_size);
if (remains >= 2048)
if (remains >= 3072)
{
while ((buck = (struct bgp_bucket *) HEAD(p->bucket_queue))->send_node.next)
{
@ -161,8 +173,19 @@ bgp_create_update(struct bgp_conn *conn, byte *buf)
bgp_free_bucket(p, buck);
continue;
}
DBG("Processing bucket %p\n", buck);
a_size = bgp_encode_attrs(p, w+2, buck->eattrs, 1024);
a_size = bgp_encode_attrs(p, w+2, buck->eattrs, 2048);
if (a_size < 0)
{
log(L_ERR "%s: Attribute list too long, skipping corresponding route group", p->p.name);
bgp_flush_prefixes(p, buck);
rem_node(&buck->send_node);
bgp_free_bucket(p, buck);
continue;
}
put_u16(w, a_size);
w += a_size + 2;
r_size = bgp_encode_prefixes(p, w, buck, remains - a_size);
@ -211,11 +234,12 @@ bgp_create_update(struct bgp_conn *conn, byte *buf)
*tmp++ = 1;
ea->attrs[0].u.ptr->length = bgp_encode_prefixes(p, tmp, buck, remains-11);
size = bgp_encode_attrs(p, w, ea, remains);
ASSERT(size >= 0);
w += size;
remains -= size;
}
if (remains >= 2048)
if (remains >= 3072)
{
while ((buck = (struct bgp_bucket *) HEAD(p->bucket_queue))->send_node.next)
{
@ -226,8 +250,19 @@ bgp_create_update(struct bgp_conn *conn, byte *buf)
bgp_free_bucket(p, buck);
continue;
}
DBG("Processing bucket %p\n", buck);
size = bgp_encode_attrs(p, w, buck->eattrs, 1024);
size = bgp_encode_attrs(p, w, buck->eattrs, 2048);
if (size < 0)
{
log(L_ERR "%s: Attribute list too long, ignoring corresponding route group", p->p.name);
bgp_flush_prefixes(p, buck);
rem_node(&buck->send_node);
bgp_free_bucket(p, buck);
continue;
}
w += size;
remains -= size;
tstart = tmp = bgp_attach_attr_wa(&ea, bgp_linpool, BA_MP_REACH_NLRI, remains-8);
@ -274,7 +309,9 @@ bgp_create_update(struct bgp_conn *conn, byte *buf)
*tmp++ = 0; /* No SNPA information */
tmp += bgp_encode_prefixes(p, tmp, buck, remains - (8+3+32+1));
ea->attrs[0].u.ptr->length = tmp - tstart;
w += bgp_encode_attrs(p, w, ea, remains);
size = bgp_encode_attrs(p, w, ea, remains);
ASSERT(size >= 0);
w += size;
break;
}
}