return rn->local_label;
}
+/**
+ * This is passed as the callback function to bgp_labelpool.c:bgp_lp_get()
+ * by bgp_reg_dereg_for_label() when a label needs to be obtained from
+ * label pool.
+ * Note that it will reject the allocated label if a label index is found,
+ * because the label index supposes predictable labels
+ */
+int bgp_reg_for_label_callback(mpls_label_t new_label, void *labelid,
+ bool allocated)
+{
+ struct bgp_path_info *pi = (struct bgp_path_info *)labelid;
+ struct bgp_node *rn = (struct bgp_node *)pi->net;
+ char addr[PREFIX_STRLEN];
+
+ prefix2str(&rn->p, addr, PREFIX_STRLEN);
+
+ if (BGP_DEBUG(labelpool, LABELPOOL))
+ zlog_debug("%s: FEC %s label=%u, allocated=%d", __func__, addr,
+ new_label, allocated);
+
+ if (!allocated) {
+ /*
+ * previously-allocated label is now invalid
+ */
+ if (pi->attr->label_index == MPLS_INVALID_LABEL_INDEX
+ && pi->attr->label != MPLS_LABEL_NONE
+ && CHECK_FLAG(rn->flags, BGP_NODE_REGISTERED_FOR_LABEL)) {
+ bgp_unregister_for_label(rn);
+ label_ntop(MPLS_LABEL_IMPLICIT_NULL, 1,
+ &rn->local_label);
+ bgp_set_valid_label(&rn->local_label);
+ }
+ return 0;
+ }
+
+ /*
+ * label index is assigned, this should be handled by SR-related code,
+ * so retry FEC registration and then reject label allocation for
+ * it to be released to label pool
+ */
+ if (pi->attr->label_index != MPLS_INVALID_LABEL_INDEX) {
+ flog_err(
+ EC_BGP_LABEL,
+ "%s: FEC %s Rejecting allocated label %u as Label Index is %u",
+ __func__, addr, new_label, pi->attr->label_index);
+
+ bgp_register_for_label(pi->net, pi);
+
+ return -1;
+ }
+
+ if (pi->attr->label != MPLS_INVALID_LABEL) {
+ if (new_label == pi->attr->label) {
+ /* already have same label, accept but do nothing */
+ return 0;
+ }
+ /* Shouldn't happen: different label allocation */
+ flog_err(EC_BGP_LABEL,
+ "%s: %s had label %u but got new assignment %u",
+ __func__, addr, pi->attr->label, new_label);
+ /* continue means use new one */
+ }
+
+ label_ntop(new_label, 1, &rn->local_label);
+ bgp_set_valid_label(&rn->local_label);
+
+ /*
+ * Get back to registering the FEC
+ */
+ bgp_register_for_label(pi->net, pi);
+
+ return 0;
+}
+
void bgp_reg_dereg_for_label(struct bgp_node *rn, struct bgp_path_info *pi,
- int reg)
+ bool reg)
{
+ bool with_label_index = false;
struct stream *s;
struct prefix *p;
+ mpls_label_t *local_label;
int command;
uint16_t flags = 0;
size_t flags_pos = 0;
+ char addr[PREFIX_STRLEN];
+
+ p = &(rn->p);
+ local_label = &(rn->local_label);
+ /* this prevents the loop when we're called by
+ * bgp_reg_for_label_callback()
+ */
+ bool have_label_to_reg = bgp_is_valid_label(local_label)
+ && label_pton(local_label) != MPLS_LABEL_IMPLICIT_NULL;
+
+ if (reg) {
+ assert(pi);
+ /*
+ * Determine if we will let zebra should derive label from
+ * label index instead of bgpd requesting from label pool
+ */
+ if (CHECK_FLAG(pi->attr->flag,
+ ATTR_FLAG_BIT(BGP_ATTR_PREFIX_SID))
+ && pi->attr->label_index != BGP_INVALID_LABEL_INDEX) {
+ with_label_index = true;
+ } else {
+ /*
+ * If no label index was provided -- assume any label
+ * from label pool will do. This means that label index
+ * always takes precedence over auto-assigned labels.
+ */
+ if (!have_label_to_reg) {
+ if (BGP_DEBUG(labelpool, LABELPOOL)) {
+ prefix2str(p, addr, PREFIX_STRLEN);
+ zlog_debug("%s: Requesting label from LP for %s",
+ __func__, addr);
+ }
+ /* bgp_reg_for_label_callback() will call back
+ * __func__ when it gets a label from the pool.
+ * This means we'll never register FECs without
+ * valid labels.
+ */
+ bgp_lp_get(LP_TYPE_BGP_LU, pi,
+ bgp_reg_for_label_callback);
+ return;
+ }
+ }
+ }
/* Check socket. */
if (!zclient || zclient->sock < 0)
return;
- p = &(rn->p);
+ /* If the route node has a local_label assigned or the
+ * path node has an MPLS SR label index allowing zebra to
+ * derive the label, proceed with registration. */
s = zclient->obuf;
stream_reset(s);
command = (reg) ? ZEBRA_FEC_REGISTER : ZEBRA_FEC_UNREGISTER;
stream_putw(s, PREFIX_FAMILY(p));
stream_put_prefix(s, p);
if (reg) {
- assert(pi);
- if (pi->attr->flag & ATTR_FLAG_BIT(BGP_ATTR_PREFIX_SID)) {
- if (pi->attr->label_index != BGP_INVALID_LABEL_INDEX) {
- flags |= ZEBRA_FEC_REGISTER_LABEL_INDEX;
- stream_putl(s, pi->attr->label_index);
- }
+ if (have_label_to_reg) {
+ flags |= ZEBRA_FEC_REGISTER_LABEL;
+ stream_putl(s, label_pton(local_label));
+ } else if (with_label_index) {
+ flags |= ZEBRA_FEC_REGISTER_LABEL_INDEX;
+ stream_putl(s, pi->attr->label_index);
}
SET_FLAG(rn->flags, BGP_NODE_REGISTERED_FOR_LABEL);
} else
projects / mirror_frr.git / blobdiff