Commit feae132e authored by Ondrej Zajicek (work)'s avatar Ondrej Zajicek (work)
Browse files

Do not initialize route metrics in import_control hook 

During route export, the receiving protocol often initialized route
metrics to default value in its import_control hook before export filter
was executed. This is inconsistent with the expectation that an export
filter would process the same route as one in the routing table and it
breaks setting these metrics before (e.g. for static routes directly in
static protocol).

The patch removes the initialization of route metrics in import_control
hook, the default values are already handled in rt_notify hook called
after export filters.

The patch also changed the behavior of OSPF to keep metrics when a route
is reannounced between OSPF instances (to be consistent with other
protocols) and the behavior when both ospf_metric1 and ospf_metric2
are specified (to have more expected behavior).
parent b24b7811

doc/bird.sgml

+10 −5
Original line number Diff line number Diff line
@@ -1618,9 +1618,7 @@ regarded as empty bgppath/*clist for most purposes. 
	The optional attribute that can be used to specify a distance to the

	network for routes that do not have a native protocol metric attribute

	(like <cf/ospf_metric1/ for OSPF routes). It is used mainly by BGP to

	compare internal distances to boundary routers (see below). It is also

	used when the route is exported to OSPF as a default value for OSPF type

	1 metric.

	compare internal distances to boundary routers (see below).

</descrip>



<p>There also exist protocol-specific attributes which are described in the
@@ -3536,8 +3534,15 @@ protocol ospf [v2|v3] &lt;name&gt; { 
with internal <cf/metric/, a <cf/metric of type 2/ is always longer than any

<cf/metric of type 1/ or any <cf/internal metric/. <cf/Internal metric/ or

<cf/metric of type 1/ is stored in attribute <cf/ospf_metric1/, <cf/metric type

2/ is stored in attribute <cf/ospf_metric2/. If you specify both metrics only

metric1 is used.

2/ is stored in attribute <cf/ospf_metric2/.



When both metrics are specified then <cf/metric of type 2/ is used. This is

relevant e.g. when a type 2 external route is propagated from one OSPF domain to

another and <cf/ospf_metric1/ is an internal distance to the original ASBR,

while <cf/ospf_metric2/ stores the type 2 metric. Note that in such cases if

<cf/ospf_metric1/ is non-zero then <cf/ospf_metric2/ is increased by one to

ensure monotonicity of metric, as internal distance is reset to zero when an

external route is announced.



<p>Each external route can also carry attribute <cf/ospf_tag/ which is a 32-bit

integer which is used when exporting routes to other protocols; otherwise, it

proto/babel/babel.c

+3 −9
Original line number Diff line number Diff line
@@ -2087,20 +2087,14 @@ babel_prepare_attrs(struct linpool *pool, ea_list *next, uint metric, u64 router 




static int

babel_import_control(struct proto *P, struct rte **new, struct ea_list **attrs, struct linpool *pool)

babel_import_control(struct proto *P, struct rte **new, struct ea_list **attrs UNUSED, struct linpool *pool UNUSED)

{

  struct babel_proto *p = (void *) P;

  rte *rt = *new;

  rte *e = *new;



  /* Reject our own unreachable routes */

  if ((rt->attrs->dest == RTD_UNREACHABLE) && (rt->attrs->src->proto == P))

  if ((e->attrs->dest == RTD_UNREACHABLE) && (e->attrs->src->proto == P))

    return -1;





  /* Prepare attributes with initial values */

  if (rt->attrs->source != RTS_BABEL)

    *attrs = babel_prepare_attrs(pool, NULL, 0, p->router_id);



  return 0;

}

proto/ospf/ospf.c

+6 −19
Original line number Diff line number Diff line
@@ -446,34 +446,21 @@ ospf_disp(timer * timer) 
 * import to the filters.

 */

static int

ospf_import_control(struct proto *P, rte **new, ea_list **attrs, struct linpool *pool)

ospf_import_control(struct proto *P, rte **new, ea_list **attrs UNUSED, struct linpool *pool UNUSED)

{

  struct ospf_proto *p = (struct ospf_proto *) P;

  struct ospf_area *oa = ospf_main_area(p);

  rte *e = *new;



  /* Reject our own routes */

  if (e->attrs->src->proto == P)

    return -1;			/* Reject our own routes */

    return -1;



  /* Do not export routes to stub areas */

  if (oa_is_stub(oa))

    return -1;			/* Do not export routes to stub areas */



  ea_list *ea = e->attrs->eattrs;

  u32 m0 = ea_get_int(ea, EA_GEN_IGP_METRIC, LSINFINITY);

  u32 m1 = MIN(m0, LSINFINITY);

  u32 m2 = 10000;

  u32 tag = 0;



  /* Hack for setting attributes directly in static protocol */

  if (e->attrs->source == RTS_STATIC)

  {

    m1 = ea_get_int(ea, EA_OSPF_METRIC1, m1);

    m2 = ea_get_int(ea, EA_OSPF_METRIC2, 10000);

    tag = ea_get_int(ea, EA_OSPF_TAG, 0);

  }

    return -1;



  *attrs = ospf_build_attrs(*attrs, pool, m1, m2, tag, 0);

  return 0;			/* Leave decision to the filters */

  return 0;

}



static struct ea_list *

proto/ospf/topology.c

+26 −6
Original line number Diff line number Diff line
@@ -1281,14 +1281,34 @@ ospf_rt_notify(struct proto *P, struct channel *ch UNUSED, net *n, rte *new, rte 


  /* Get route attributes */

  rta *a = new->attrs;

  u32 m1 = ea_get_int(ea, EA_OSPF_METRIC1, LSINFINITY);

  u32 m2 = ea_get_int(ea, EA_OSPF_METRIC2, 10000);

  int ebit = (m1 == LSINFINITY);

  u32 metric = ebit ? m2 : m1;

  u32 tag = ea_get_int(ea, EA_OSPF_TAG, 0);

  ip_addr fwd = IPA_NONE;

  eattr *m1a = ea_find(ea, EA_OSPF_METRIC1);

  eattr *m2a = ea_find(ea, EA_OSPF_METRIC2);

  uint m1 = m1a ? m1a->u.data : 0;

  uint m2 = m2a ? m2a->u.data : 10000;



  if (m1 > LSINFINITY)

  {

    log(L_WARN "%s: Invalid ospf_metric1 value %u for route %N",

	p->p.name, m1, n->n.addr);

    m1 = LSINFINITY;

  }



  if (m2 > LSINFINITY)

  {

    log(L_WARN "%s: Invalid ospf_metric2 value %u for route %N",

	p->p.name, m2, n->n.addr);

    m2 = LSINFINITY;

  }



  /* Ensure monotonicity of metric if both m1 and m2 are used */

  if ((m1 > 0) && (m2 < LSINFINITY))

    m2++;



  uint ebit = m2a || !m1a;

  uint metric = ebit ? m2 : m1;

  uint tag = ea_get_int(ea, EA_OSPF_TAG, 0);



  ip_addr fwd = IPA_NONE;

  if ((a->dest == RTD_UNICAST) && use_gw_for_fwaddr(p, a->nh.gw, a->nh.iface))

    fwd = a->nh.gw;

proto/rip/rip.c

+1 −11
Original line number Diff line number Diff line
@@ -1020,16 +1020,6 @@ rip_prepare_attrs(struct linpool *pool, ea_list *next, u8 metric, u16 tag) 
  return l;

}



static int

rip_import_control(struct proto *P UNUSED, struct rte **rt, struct ea_list **attrs, struct linpool *pool)

{

  /* Prepare attributes with initial values */

  if ((*rt)->attrs->source != RTS_RIP)

    *attrs = rip_prepare_attrs(pool, *attrs, 1, 0);



  return 0;

}



static void

rip_reload_routes(struct channel *C)

{
@@ -1091,7 +1081,7 @@ rip_init(struct proto_config *CF) 
  P->if_notify = rip_if_notify;

  P->rt_notify = rip_rt_notify;

  P->neigh_notify = rip_neigh_notify;

  P->import_control = rip_import_control;

  // P->import_control = rip_import_control;

  P->reload_routes = rip_reload_routes;

  P->make_tmp_attrs = rip_make_tmp_attrs;

  P->store_tmp_attrs = rip_store_tmp_attrs;

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