This commit is the last missing piece to complete BGP LU support in bgpd. To this moment, bgpd (and zebra) supported auto label assignment only for prefixes leaked from VRFs to vpn and for MPLS SR prefixes. This adds auto label assignment to other routes types in bgpd. The following enhancements have been made:
* bgp_route.c:bgp_process_main_one() now sets implicit-null local_label to all local, aggregate and redistributed routes.
* bgp_route.c:bgp_process_main_one() now will request a label from the label pool for any prefix that loses the label for some reason (for example, when the static label assignment config is removed)
* bgp_label.c:bgp_reg_dereg_for_label() now requests labels from label pool for routes which have no associated label index
* zebra_mpls.c:zebra_mpls_fec_register() now expects both label and label_index from the calling function, one of which must be set to MPLS_INVALID_LABEL or MPLS_INVALID_LABEL_INDEX, based on this it will decide how to register the provided FEC.
Signed-off-by: Anton Degtyarev <anton@cumulusnetworks.com>
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
struct bgp_path_info;
struct peer;
+extern int bgp_reg_for_label_callback(mpls_label_t new_label, void *labelid,
+ bool allocated);
extern void bgp_reg_dereg_for_label(struct bgp_node *rn,
- struct bgp_path_info *pi, int reg);
+ struct bgp_path_info *pi, bool reg);
extern int bgp_parse_fec_update(void);
extern mpls_label_t bgp_adv_label(struct bgp_node *rn, struct bgp_path_info *pi,
struct peer *to, afi_t afi, safi_t safi);
static inline void bgp_register_for_label(struct bgp_node *rn,
struct bgp_path_info *pi)
{
- bgp_reg_dereg_for_label(rn, pi, 1);
+ bgp_reg_dereg_for_label(rn, pi, true);
}
static inline void bgp_unregister_for_label(struct bgp_node *rn)
{
- bgp_reg_dereg_for_label(rn, NULL, 0);
+ bgp_reg_dereg_for_label(rn, NULL, false);
}
/* Label stream to value */
* Types used in bgp_lp_get for debug tracking; add more as needed
*/
#define LP_TYPE_VRF 0x00000001
+#define LP_TYPE_BGP_LU 0x00000002
struct labelpool {
struct skiplist *ledger; /* all requests */
/* Do we need to allocate or free labels?
* Right now, since we only deal with per-prefix labels, it is not
- * necessary to do this upon changes to best path except if the label
- * index changes
+ * necessary to do this upon changes to best path. Exceptions:
+ * - label index has changed -> recalculate resulting label
+ * - path_info sub_type changed -> switch to/from implicit-null
+ * - no valid label (due to removed static label binding) -> get new one
*/
if (bgp->allocate_mpls_labels[afi][safi]) {
if (new_select) {
if (!old_select
|| bgp_label_index_differs(new_select, old_select)
- || new_select->sub_type != old_select->sub_type) {
+ || new_select->sub_type != old_select->sub_type
+ || !bgp_is_valid_label(&rn->local_label)) {
+ /* Enforced penultimate hop popping:
+ * implicit-null for local routes, aggregate
+ * and redistributed routes
+ */
if (new_select->sub_type == BGP_ROUTE_STATIC
- && new_select->attr->flag
- & ATTR_FLAG_BIT(
- BGP_ATTR_PREFIX_SID)
- && new_select->attr->label_index
- != BGP_INVALID_LABEL_INDEX) {
+ || new_select->sub_type
+ == BGP_ROUTE_AGGREGATE
+ || new_select->sub_type
+ == BGP_ROUTE_REDISTRIBUTE) {
if (CHECK_FLAG(
rn->flags,
BGP_NODE_REGISTERED_FOR_LABEL))
#define ZEBRA_IPTABLES_FORWARD 0
#define ZEBRA_IPTABLES_DROP 1
+/* Zebra FEC register command flags. */
+#define ZEBRA_FEC_REGISTER_LABEL 0x1
+#define ZEBRA_FEC_REGISTER_LABEL_INDEX 0x2
+
extern struct sockaddr_storage zclient_addr;
extern socklen_t zclient_addr_len;
*/
#define ZEBRA_FLAG_ONLINK 0x80
-/* Zebra FEC flags. */
-#define ZEBRA_FEC_REGISTER_LABEL_INDEX 0x1
-
#ifndef INADDR_LOOPBACK
#define INADDR_LOOPBACK 0x7f000001 /* Internet address 127.0.0.1. */
#endif
unsigned short l = 0;
struct prefix p;
uint16_t flags;
+ uint32_t label = MPLS_INVALID_LABEL;
uint32_t label_index = MPLS_INVALID_LABEL_INDEX;
s = msg;
l += 5;
STREAM_GET(&p.u.prefix, s, PSIZE(p.prefixlen));
l += PSIZE(p.prefixlen);
- if (flags & ZEBRA_FEC_REGISTER_LABEL_INDEX) {
+ if (flags & ZEBRA_FEC_REGISTER_LABEL) {
+ STREAM_GETL(s, label);
+ l += 4;
+ } else if (flags & ZEBRA_FEC_REGISTER_LABEL_INDEX) {
STREAM_GETL(s, label_index);
l += 4;
- } else
- label_index = MPLS_INVALID_LABEL_INDEX;
- zebra_mpls_fec_register(zvrf, &p, label_index, client);
+ }
+
+ zebra_mpls_fec_register(zvrf, &p, label, label_index, client);
}
stream_failure:
.description = "A client requested a label binding for a new FEC, but Zebra was unable to add the FEC to its internal table.",
.suggestion = "Notify a developer.",
},
+ {
+ .code = EC_ZEBRA_FEC_LABEL_INDEX_LABEL_CONFLICT,
+ .title = "Refused to add FEC for MPLS client with both label index and label specified",
+ .description = "A client requested a label binding for a new FEC specifying a label index and a label at the same time.",
+ .suggestion = "Notify a developer.",
+ },
{
.code = EC_ZEBRA_FEC_RM_FAILED,
.title = "Failed to remove FEC for MPLS client",
EC_ZEBRA_DP_INVALID_RC,
EC_ZEBRA_WQ_NONEXISTENT,
EC_ZEBRA_FEC_ADD_FAILED,
+ EC_ZEBRA_FEC_LABEL_INDEX_LABEL_CONFLICT,
EC_ZEBRA_FEC_RM_FAILED,
EC_ZEBRA_IRDP_LEN_MISMATCH,
EC_ZEBRA_RNH_UNKNOWN_FAMILY,
* NOTE: If there is a manually configured label binding, that is used.
* Otherwise, if a label index is specified, it means we have to allocate the
* label from a locally configured label block (SRGB), if one exists and index
- * is acceptable.
+ * is acceptable. If no label index then just register the specified label.
+ * NOTE2: Either label or label_index is expected to be set to MPLS_INVALID_*
+ * by the calling function. Register requests with both will be rejected.
*/
int zebra_mpls_fec_register(struct zebra_vrf *zvrf, struct prefix *p,
- uint32_t label_index, struct zserv *client)
+ uint32_t label, uint32_t label_index,
+ struct zserv *client)
{
struct route_table *table;
zebra_fec_t *fec;
char buf[BUFSIZ];
- int new_client;
- int label_change = 0;
+ bool new_client;
+ bool label_change = false;
uint32_t old_label;
+ bool have_label_index = (label_index != MPLS_INVALID_LABEL_INDEX);
+ bool is_configured_fec = false; /* indicate statically configured FEC */
table = zvrf->fec_table[family2afi(PREFIX_FAMILY(p))];
if (!table)
if (IS_ZEBRA_DEBUG_MPLS)
prefix2str(p, buf, BUFSIZ);
+ if (label != MPLS_INVALID_LABEL && have_label_index) {
+ flog_err(
+ EC_ZEBRA_FEC_LABEL_INDEX_LABEL_CONFLICT,
+ "Rejecting FEC register for %s with both label %u and Label Index %u specified, client %s",
+ buf, label, label_index,
+ zebra_route_string(client->proto));
+ return -1;
+ }
+
/* Locate FEC */
fec = fec_find(table, p);
if (!fec) {
- fec = fec_add(table, p, MPLS_INVALID_LABEL, 0, label_index);
+ fec = fec_add(table, p, label, 0, label_index);
if (!fec) {
- prefix2str(p, buf, BUFSIZ);
flog_err(
EC_ZEBRA_FEC_ADD_FAILED,
"Failed to add FEC %s upon register, client %s",
}
old_label = MPLS_INVALID_LABEL;
- new_client = 1;
+ new_client = true;
} else {
+ /* Check if the FEC has been statically defined in the config */
+ is_configured_fec = fec->flags & FEC_FLAG_CONFIGURED;
/* Client may register same FEC with different label index. */
new_client =
(listnode_lookup(fec->client_list, client) == NULL);
- if (!new_client && fec->label_index == label_index)
+ if (!new_client && fec->label_index == label_index
+ && fec->label == label)
/* Duplicate register */
return 0;
- /* Save current label, update label index */
+ /* Save current label, update the FEC */
old_label = fec->label;
fec->label_index = label_index;
}
listnode_add(fec->client_list, client);
if (IS_ZEBRA_DEBUG_MPLS)
- zlog_debug("FEC %s Label Index %u %s by client %s", buf,
- label_index, new_client ? "registered" : "updated",
- zebra_route_string(client->proto));
-
- /* If not a configured FEC, derive the local label (from label index)
- * or reset it.
+ zlog_debug("FEC %s label%s %u %s by client %s%s", buf,
+ have_label_index ? " index" : "",
+ have_label_index ? label_index : label,
+ new_client ? "registered" : "updated",
+ zebra_route_string(client->proto),
+ is_configured_fec
+ ? ", but using statically configured label"
+ : "");
+
+ /* If not a statically configured FEC, derive the local label
+ * from label index or use the provided label
*/
- if (!(fec->flags & FEC_FLAG_CONFIGURED)) {
- fec_derive_label_from_index(zvrf, fec);
+ if (!is_configured_fec) {
+ if (have_label_index)
+ fec_derive_label_from_index(zvrf, fec);
+ else
+ fec->label = label;
/* If no label change, exit. */
if (fec->label == old_label)
return 0;
- label_change = 1;
+ label_change = true;
}
/* If new client or label change, update client and install or uninstall
if (IS_ZEBRA_DEBUG_MPLS) {
prefix2str(p, buf, BUFSIZ);
- zlog_debug("Delete fec %s label index %u", buf,
- fec->label_index);
+ zlog_debug("Delete fec %s label %u label index %u", buf,
+ fec->label, fec->label_index);
}
old_label = fec->label;
int zebra_mpls_lsp_uninstall(struct zebra_vrf *zvrf, struct route_node *rn,
struct route_entry *re);
-/*
- * Registration from a client for the label binding for a FEC. If a binding
- * already exists, it is informed to the client.
- * NOTE: If there is a manually configured label binding, that is used.
- * Otherwise, if aa label index is specified, it means we have to allocate the
- * label from a locally configured label block (SRGB), if one exists and index
- * is acceptable.
- */
int zebra_mpls_fec_register(struct zebra_vrf *zvrf, struct prefix *p,
- uint32_t label_index, struct zserv *client);
+ uint32_t label, uint32_t label_index,
+ struct zserv *client);
/*
* Deregistration from a client for the label binding for a FEC. The FEC
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