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Fixes BGP IPv6 link local next hop handling.

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When sending 'third party' BGP update, Bird used bogus link local
addresses instead of addresses it received before.
This commit is contained in:
Ondrej Zajicek
2009-04-29 18:58:24 +02:00
parent ad440a570b
commit 4827b69ff4
4 changed files with 54 additions and 23 deletions
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51
proto/bgp/packets.c
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@@ -234,10 +234,10 @@ bgp_create_update(struct bgp_conn *conn, byte *buf)
{
struct bgp_proto *p = conn->bgp;
struct bgp_bucket *buck;
int size, is_ll;
int size;
int remains = BGP_MAX_PACKET_LENGTH - BGP_HEADER_LENGTH - 4;
byte *w, *tmp, *tstart;
ip_addr ip, ip_ll;
ip_addr *ipp, ip, ip_ll;
ea_list *ea;
eattr *nh;
neighbor *n;
@@ -291,26 +291,31 @@ bgp_create_update(struct bgp_conn *conn, byte *buf)
*tmp++ = 1;
nh = ea_find(buck->eattrs, EA_CODE(EAP_BGP, BA_NEXT_HOP));
ASSERT(nh);
ip = *(ip_addr *) nh->u.ptr->data;
is_ll = 0;
/* We have two addresses here in 'nh'. Really. */
ipp = (ip_addr *) nh->u.ptr->data;
ip = ipp[0];
ip_ll = IPA_NONE;
if (ipa_equal(ip, p->source_addr))
{
is_ll = 1;
ip_ll = p->local_link;
}
ip_ll = p->local_link;
else
{
/* If we send a route with 'third party' next hop destinated
* in the same interface, we should also send a link local
* next hop address. We use the received one (stored in the
* other part of BA_NEXT_HOP eattr). If we didn't received
* it (for example it is a static route), we do not send link
* local next hop address. It is contrary to RFC 2545, but
* probably the only sane possibility.
*/
n = neigh_find(&p->p, &ip, 0);
if (n && n->iface == p->neigh->iface)
{
/* FIXME: We are assuming the global scope addresses use the lower 64 bits
* as an interface identifier which hasn't necessarily to be true.
*/
is_ll = 1;
ip_ll = ipa_or(ipa_build(0xfe800000,0,0,0), ipa_and(ip, ipa_build(0,0,~0,~0)));
}
ip_ll = ipp[1];
}
if (is_ll)
if (ipa_nonzero(ip_ll))
{
*tmp++ = 32;
ipa_hton(ip);
@@ -326,6 +331,7 @@ bgp_create_update(struct bgp_conn *conn, byte *buf)
memcpy(tmp, &ip, 16);
tmp += 16;
}
*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;
@@ -778,9 +784,18 @@ bgp_do_rx_update(struct bgp_conn *conn,
if (len < 1 || (*x != 16 && *x != 32) || len < *x + 2)
goto bad;
byte *nh = bgp_attach_attr_wa(&a0->eattrs, bgp_linpool, BA_NEXT_HOP, 16);
ip_addr *nh = (ip_addr *) bgp_attach_attr_wa(&a0->eattrs, bgp_linpool, BA_NEXT_HOP, NEXT_HOP_LENGTH);
memcpy(nh, x+1, 16);
ipa_ntoh(*(ip_addr *)nh);
ipa_ntoh(nh[0]);
/* We store received link local address in the other part of BA_NEXT_HOP eattr. */
if (*x == 32)
{
memcpy(nh+1, x+17, 16);
ipa_ntoh(nh[1]);
}
else
nh[1] = IPA_NONE;
/* Also ignore one reserved byte */
len -= *x + 2;