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Implements support for link-local addresses in BGP.

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Thanks Matthias Schiffer for the original patch.
This commit is contained in:
Ondrej Zajicek 2012-01-08 15:28:27 +01:00
parent eb1451a3a0
commit 53ffbff39f
6 changed files with 91 additions and 23 deletions
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18
lib/printf.c
View File

@ -12,6 +12,8 @@
#include <errno.h>
#include "nest/iface.h"
/* we use this so that we can do without the ctype library */
#define is_digit(c) ((c) >= '0' && (c) <= '9')
@ -138,6 +140,7 @@ int bvsnprintf(char *buf, int size, const char *fmt, va_list args)
char *str, *start;
const char *s;
char ipbuf[STD_ADDRESS_P_LENGTH+1];
struct iface *iface;
int flags; /* flags to number() */
@ -279,6 +282,21 @@ int bvsnprintf(char *buf, int size, const char *fmt, va_list args)
s = ipbuf;
goto str;
/* Interface scope after link-local IP address */
case 'J':
iface = va_arg(args, struct iface *);
if (!iface)
continue;
if (!size)
return -1;
*str++ = '%';
start++;
size--;
s = iface->name;
goto str;
/* Router/Network ID - essentially IPv4 address in u32 value */
case 'R':
x = va_arg(args, u32);

7
proto/bgp/attrs.c
View File

@ -1001,10 +1001,13 @@ bgp_update_attrs(struct bgp_proto *p, rte *e, ea_list **attrs, struct linpool *p
}
/* iBGP -> keep next_hop, eBGP multi-hop -> use source_addr,
eBGP single-hop -> keep next_hop if on the same iface */
* eBGP single-hop -> keep next_hop if on the same iface.
* If the next_hop is zero (i.e. link-local), keep only if on the same iface.
*/
a = ea_find(e->attrs->eattrs, EA_CODE(EAP_BGP, BA_NEXT_HOP));
if (a && !p->cf->next_hop_self &&
(p->is_internal || (p->neigh && (e->attrs->iface == p->neigh->iface))))
((p->is_internal && ipa_nonzero(*((ip_addr *) a->u.ptr->data))) ||
(p->neigh && (e->attrs->iface == p->neigh->iface))))
{
/* Leave the original next hop attribute, will check later where does it point */
}

35
proto/bgp/bgp.c
View File

@ -111,7 +111,7 @@ bgp_open(struct bgp_proto *p)
if (p->cf->password)
{
int rv = sk_set_md5_auth(bgp_listen_sk, p->cf->remote_ip, p->cf->password);
int rv = sk_set_md5_auth(bgp_listen_sk, p->cf->remote_ip, p->cf->iface, p->cf->password);
if (rv < 0)
{
bgp_close(p, 0);
@ -178,7 +178,7 @@ bgp_close(struct bgp_proto *p, int apply_md5)
bgp_counter--;
if (p->cf->password && apply_md5)
sk_set_md5_auth(bgp_listen_sk, p->cf->remote_ip, NULL);
sk_set_md5_auth(bgp_listen_sk, p->cf->remote_ip, p->cf->iface, NULL);
if (!bgp_counter)
{
@ -578,6 +578,7 @@ bgp_connect(struct bgp_proto *p) /* Enter Connect state and start establishing c
s->type = SK_TCP_ACTIVE;
s->saddr = p->source_addr;
s->daddr = p->cf->remote_ip;
s->iface = p->neigh ? p->neigh->iface : NULL;
s->dport = BGP_PORT;
s->ttl = p->cf->ttl_security ? 255 : hops;
s->rbsize = BGP_RX_BUFFER_SIZE;
@ -585,7 +586,8 @@ bgp_connect(struct bgp_proto *p) /* Enter Connect state and start establishing c
s->tos = IP_PREC_INTERNET_CONTROL;
s->password = p->cf->password;
s->tx_hook = bgp_connected;
BGP_TRACE(D_EVENTS, "Connecting to %I from local address %I", s->daddr, s->saddr);
BGP_TRACE(D_EVENTS, "Connecting to %I%J from local address %I%J", s->daddr, p->cf->iface,
s->saddr, ipa_has_link_scope(s->saddr) ? s->iface : NULL);
bgp_setup_conn(p, conn);
bgp_setup_sk(conn, s);
bgp_conn_set_state(conn, BS_CONNECT);
@ -634,14 +636,16 @@ bgp_incoming_connection(sock *sk, int dummy UNUSED)
if (pc->protocol == &proto_bgp && pc->proto)
{
struct bgp_proto *p = (struct bgp_proto *) pc->proto;
if (ipa_equal(p->cf->remote_ip, sk->daddr))
if (ipa_equal(p->cf->remote_ip, sk->daddr) &&
(!ipa_has_link_scope(sk->daddr) || (p->cf->iface == sk->iface)))
{
/* We are in proper state and there is no other incoming connection */
int acc = (p->p.proto_state == PS_START || p->p.proto_state == PS_UP) &&
(p->start_state >= BSS_CONNECT) && (!p->incoming_conn.sk);
BGP_TRACE(D_EVENTS, "Incoming connection from %I (port %d) %s",
sk->daddr, sk->dport, acc ? "accepted" : "rejected");
BGP_TRACE(D_EVENTS, "Incoming connection from %I%J (port %d) %s",
sk->daddr, ipa_has_link_scope(sk->daddr) ? sk->iface : NULL,
sk->dport, acc ? "accepted" : "rejected");
if (!acc)
goto err;
@ -667,7 +671,8 @@ bgp_incoming_connection(sock *sk, int dummy UNUSED)
}
}
log(L_WARN "BGP: Unexpected connect from unknown address %I (port %d)", sk->daddr, sk->dport);
log(L_WARN "BGP: Unexpected connect from unknown address %I%J (port %d)",
sk->daddr, ipa_has_link_scope(sk->daddr) ? sk->iface : NULL, sk->dport);
err:
rfree(sk);
return 0;
@ -713,6 +718,7 @@ bgp_start_neighbor(struct bgp_proto *p)
{
/* Called only for single-hop BGP sessions */
/* Remove this ? */
if (ipa_zero(p->source_addr))
p->source_addr = p->neigh->iface->addr->ip;
@ -742,7 +748,7 @@ bgp_neigh_notify(neighbor *n)
{
struct bgp_proto *p = (struct bgp_proto *) n->proto;
if (n->iface)
if (n->scope > 0)
{
if ((p->p.proto_state == PS_START) && (p->start_state == BSS_PREPARE))
{
@ -793,10 +799,10 @@ bgp_start_locked(struct object_lock *lock)
return;
}
p->neigh = neigh_find(&p->p, &cf->remote_ip, NEF_STICKY);
p->neigh = neigh_find2(&p->p, &cf->remote_ip, cf->iface, NEF_STICKY);
if (!p->neigh || (p->neigh->scope == SCOPE_HOST))
{
log(L_ERR "%s: Invalid remote address %I", p->p.name, cf->remote_ip);
log(L_ERR "%s: Invalid remote address %I%J", p->p.name, cf->remote_ip, cf->iface);
/* As we do not start yet, we can just disable protocol */
p->p.disabled = 1;
bgp_store_error(p, NULL, BE_MISC, BEM_INVALID_NEXT_HOP);
@ -807,7 +813,7 @@ bgp_start_locked(struct object_lock *lock)
if (p->neigh->scope > 0)
bgp_start_neighbor(p);
else
BGP_TRACE(D_EVENTS, "Waiting for %I to become my neighbor", cf->remote_ip);
BGP_TRACE(D_EVENTS, "Waiting for %I%J to become my neighbor", cf->remote_ip, cf->iface);
}
static int
@ -847,6 +853,7 @@ bgp_start(struct proto *P)
lock = p->lock = olock_new(P->pool);
lock->addr = p->cf->remote_ip;
lock->iface = p->cf->iface;
lock->type = OBJLOCK_TCP;
lock->port = BGP_PORT;
lock->iface = NULL;
@ -951,6 +958,10 @@ bgp_check_config(struct bgp_config *c)
if (c->multihop && (c->gw_mode == GW_DIRECT))
cf_error("Multihop BGP cannot use direct gateway mode");
if (c->multihop && (ipa_has_link_scope(c->remote_ip) ||
ipa_has_link_scope(c->source_addr)))
cf_error("Multihop BGP cannot be used with link-local addresses");
/* Different default based on rs_client */
if (!c->missing_lladdr)
c->missing_lladdr = c->rs_client ? MLL_IGNORE : MLL_SELF;
@ -1115,7 +1126,7 @@ bgp_show_proto_info(struct proto *P)
struct bgp_conn *c = p->conn;
cli_msg(-1006, " BGP state: %s", bgp_state_dsc(p));
cli_msg(-1006, " Neighbor address: %I", p->cf->remote_ip);
cli_msg(-1006, " Neighbor address: %I%J", p->cf->remote_ip, p->cf->iface);
cli_msg(-1006, " Neighbor AS: %u", p->remote_as);
if (P->proto_state == PS_START)

3
proto/bgp/bgp.h
View File

@ -19,9 +19,10 @@ struct bgp_config {
struct proto_config c;
u32 local_as, remote_as;
ip_addr remote_ip;
ip_addr source_addr; /* Source address to use */
struct iface *iface; /* Interface for link-local addresses */
int multihop; /* Number of hops if multihop */
int ttl_security; /* Enable TTL security [RFC5082] */
ip_addr source_addr; /* Source address to use */
int next_hop_self; /* Always set next hop to local IP address */
int missing_lladdr; /* What we will do when we don' know link-local addr, see MLL_* */
int gw_mode; /* How we compute route gateway from next_hop attr, see GW_* */

10
proto/bgp/config.Y
View File

@ -57,11 +57,15 @@ bgp_proto:
| bgp_proto proto_item ';'
| bgp_proto LOCAL AS expr ';' { BGP_CFG->local_as = $4; }
| bgp_proto LOCAL ipa AS expr ';' { BGP_CFG->source_addr = $3; BGP_CFG->local_as = $5; }
| bgp_proto NEIGHBOR ipa AS expr ';' {
if (ipa_nonzero(BGP_CFG->remote_ip)) cf_error("Only one neighbor per BGP instance is allowed");
| bgp_proto NEIGHBOR ipa ipa_scope AS expr ';' {
if (ipa_nonzero(BGP_CFG->remote_ip))
cf_error("Only one neighbor per BGP instance is allowed");
if (!ipa_has_link_scope($3) != !$4)
cf_error("Link-local address and interface scope must be used together");
BGP_CFG->remote_ip = $3;
BGP_CFG->remote_as = $5;
BGP_CFG->iface = $4;
BGP_CFG->remote_as = $6;
}
| bgp_proto RR CLUSTER ID idval ';' { BGP_CFG->rr_cluster_id = $5; }
| bgp_proto RR CLIENT ';' { BGP_CFG->rr_client = 1; }

39
proto/bgp/packets.c
View File

@ -318,6 +318,13 @@ bgp_create_update(struct bgp_conn *conn, byte *buf)
#else /* IPv6 version */
static inline int
same_iface(struct bgp_proto *p, ip_addr *ip)
{
neighbor *n = neigh_find(&p->p, ip, 0);
return n && p->neigh && n->iface == p->neigh->iface;
}
static byte *
bgp_create_update(struct bgp_conn *conn, byte *buf)
{
@ -329,7 +336,6 @@ bgp_create_update(struct bgp_conn *conn, byte *buf)
ip_addr *ipp, ip, ip_ll;
ea_list *ea;
eattr *nh;
neighbor *n;
put_u16(buf, 0);
w = buf+4;
@ -399,10 +405,13 @@ bgp_create_update(struct bgp_conn *conn, byte *buf)
* link local address seems to be a natural way to solve that
* problem, but it is contrary to RFC 2545 and Quagga does not
* accept such routes.
*
* There are two cases, either we have global IP, or
* IPA_NONE if the neighbor is link-local. For IPA_NONE,
* we suppose it is on the same iface, see bgp_update_attrs().
*/
n = neigh_find(&p->p, &ip, 0);
if (n && p->neigh && n->iface == p->neigh->iface)
if (ipa_zero(ip) || same_iface(p, &ip))
{
if (second && ipa_nonzero(ipp[1]))
ip_ll = ipp[1];
@ -434,6 +443,9 @@ bgp_create_update(struct bgp_conn *conn, byte *buf)
*tmp++ = BGP_AF_IPV6;
*tmp++ = 1;
if (ipa_has_link_scope(ip))
ip = IPA_NONE;
if (ipa_nonzero(ip_ll))
{
*tmp++ = 32;
@ -809,13 +821,27 @@ bgp_set_next_hop(struct bgp_proto *p, rta *a)
#ifdef IPV6
int second = (nh->u.ptr->length == NEXT_HOP_LENGTH);
/* First address should not be link-local, but may be zero in direct mode */
if (ipa_has_link_scope(*nexthop))
*nexthop = IPA_NONE;
#else
int second = 0;
#endif
if (p->cf->gw_mode == GW_DIRECT)
{
neighbor *ng = neigh_find(&p->p, nexthop, 0) ? : p->neigh;
neighbor *ng;
if (ipa_nonzero(*nexthop))
ng = neigh_find(&p->p, nexthop, 0);
else if (second) /* GW_DIRECT -> single_hop -> p->neigh != NULL */
ng = neigh_find2(&p->p, nexthop + 1, p->neigh->iface, 0);
/* Fallback */
if (!ng)
ng = p->neigh;
if (ng->scope == SCOPE_HOST)
return 0;
@ -826,7 +852,12 @@ bgp_set_next_hop(struct bgp_proto *p, rta *a)
a->igp_metric = 0;
}
else /* GW_RECURSIVE */
{
if (ipa_zero(*nexthop))
return 0;
rta_set_recursive_next_hop(p->p.table, a, p->igp_table, nexthop, nexthop + second);
}
return 1;
}