mpls_label_t label;
label = srgb.lower_bound + index;
- if (label > (srgb.lower_bound + srgb.range_size))
+ if (label > (srgb.lower_bound + srgb.range_size)) {
+ flog_warn(EC_OSPF_SR_SID_OVERFLOW,
+ "%s: SID index %u falls outside SRGB range",
+ __func__, index);
return MPLS_INVALID_LABEL;
- else
+ } else
return label;
}
return rc;
}
+/**
+ * Compute output label for the given Prefix-SID.
+ *
+ * @param srp Segment Routing Prefix
+ * @param srnext Segment Routing nexthop node
+ *
+ * @return MPLS label or MPLS_INVALID_LABEL in case of error
+ */
+static mpls_label_t sr_prefix_out_label(const struct sr_prefix *srp,
+ const struct sr_node *srnext)
+{
+ /* Check if the nexthop SR Node is the last hop? */
+ if (srnext == srp->srn) {
+ /* SR-Node doesn't request NO-PHP. Return Implicit NULL label */
+ if (!CHECK_FLAG(srp->flags, EXT_SUBTLV_PREFIX_SID_NPFLG))
+ return MPLS_LABEL_IMPLICIT_NULL;
+
+ /* SR-Node requests Explicit NULL Label */
+ if (CHECK_FLAG(srp->flags, EXT_SUBTLV_PREFIX_SID_EFLG))
+ return MPLS_LABEL_IPV4_EXPLICIT_NULL;
+ /* Fallthrough */
+ }
+
+ /* Return SID value as MPLS label if it is an Absolute SID */
+ if (CHECK_FLAG(srp->flags, EXT_SUBTLV_PREFIX_SID_VFLG
+ | EXT_SUBTLV_PREFIX_SID_LFLG)) {
+ /*
+ * V/L SIDs have local significance, so only adjacent routers
+ * can use them (RFC8665 section #5)
+ */
+ if (srp->srn != srnext)
+ return MPLS_INVALID_LABEL;
+ return srp->sid;
+ }
+
+ /* Return MPLS label as SRGB lower bound + SID index as per RFC 8665 */
+ return (index2label(srp->sid, srnext->srgb));
+}
+
/*
* Compute NHLFE entry for Extended Prefix
*
/* And store this information for later update */
srnext->neighbor = OspfSR.self;
- if (IPV4_ADDR_SAME(&srnext->adv_router, &srp->adv_router))
- path->srni.nexthop = NULL;
- else
- path->srni.nexthop = srnext;
+ path->srni.nexthop = srnext;
/*
* SR Node could be known, but SRGB could be not initialize
srnext->srgb.range_size, srnext->srgb.lower_bound,
&srnext->adv_router);
- /*
- * Compute Output Label with Nexthop SR Node SRGB or Implicit
- * Null label if next hop is the destination and request PHP
- */
- if ((path->srni.nexthop == NULL)
- && (!CHECK_FLAG(srp->flags, EXT_SUBTLV_PREFIX_SID_NPFLG)))
- path->srni.label_out = MPLS_LABEL_IMPLICIT_NULL;
- else if (CHECK_FLAG(srp->flags, EXT_SUBTLV_PREFIX_SID_VFLG))
- path->srni.label_out = srp->sid;
- else
- path->srni.label_out =
- index2label(srp->sid, srnext->srgb);
+ /* Compute Output Label with Nexthop SR Node SRGB */
+ path->srni.label_out = sr_prefix_out_label(srp, srnext);
osr_debug(" |- Computed new labels in: %u out: %u",
srp->label_in, path->srni.label_out);
for (ALL_LIST_ELEMENTS_RO(srp->route->paths, pnode, path)) {
/* Process only SID Index for next hop without PHP */
- if ((path->srni.nexthop == NULL)
+ if ((path->srni.nexthop == srp->srn)
&& (!CHECK_FLAG(srp->flags,
EXT_SUBTLV_PREFIX_SID_NPFLG)))
continue;
" |- Update Node SID %pFX - %u for self SR Node",
(struct prefix *)&srp->prefv4, srp->sid);
- /* Install NHLFE if NO-PHP is requested */
- if (CHECK_FLAG(srp->flags,
- EXT_SUBTLV_PREFIX_SID_NPFLG)) {
+ /* Install SID if NO-PHP is set and not EXPLICIT-NULL */
+ if (CHECK_FLAG(srp->flags, EXT_SUBTLV_PREFIX_SID_NPFLG)
+ && !CHECK_FLAG(srp->flags,
+ EXT_SUBTLV_PREFIX_SID_EFLG)) {
srp->label_in = index2label(srp->sid,
OspfSR.self->srgb);
srp->nhlfe.label_out = MPLS_LABEL_IMPLICIT_NULL;
for (ALL_LIST_ELEMENTS_RO(OspfSR.self->ext_prefix, node,
srp)) {
vty_out(vty,
- " segment-routing prefix %s/%u index %u%s\n",
+ " segment-routing prefix %s/%u "
+ "index %u",
inet_ntoa(srp->prefv4.prefix),
- srp->prefv4.prefixlen, srp->sid,
- CHECK_FLAG(srp->flags,
- EXT_SUBTLV_PREFIX_SID_NPFLG)
- ? " no-php-flag"
- : "");
+ srp->prefv4.prefixlen, srp->sid);
+ if (CHECK_FLAG(srp->flags,
+ EXT_SUBTLV_PREFIX_SID_EFLG))
+ vty_out(vty, " explicit-null\n");
+ else if (CHECK_FLAG(
+ srp->flags,
+ EXT_SUBTLV_PREFIX_SID_NPFLG))
+ vty_out(vty, " no-php-flag\n");
+ else
+ vty_out(vty, "\n");
}
}
}
DEFUN (sr_prefix_sid,
sr_prefix_sid_cmd,
- "segment-routing prefix A.B.C.D/M index (0-65535) [no-php-flag]",
+ "segment-routing prefix A.B.C.D/M index (0-65535) [no-php-flag|explicit-null]",
SR_STR
"Prefix SID\n"
"IPv4 Prefix as A.B.C.D/M\n"
"SID index for this prefix in decimal (0-65535)\n"
"Index value inside SRGB (lower_bound < index < upper_bound)\n"
- "Don't request Penultimate Hop Popping (PHP)\n")
+ "Don't request Penultimate Hop Popping (PHP)\n"
+ "Upstream neighbor must replace prefix-sid with explicit null label\n")
{
int idx = 0;
struct prefix p;
uint32_t index;
struct listnode *node;
- struct sr_prefix *srp, *new;
+ struct sr_prefix *srp, *new = NULL;
struct interface *ifp;
if (!ospf_sr_enabled(vty))
return CMD_WARNING_CONFIG_FAILED;
}
- /* check that the index is not already used */
+ /* Search for an existing Prefix-SID */
for (ALL_LIST_ELEMENTS_RO(OspfSR.self->ext_prefix, node, srp)) {
if (srp->sid == index) {
- vty_out(vty, "Index %u is already used\n", index);
- return CMD_WARNING_CONFIG_FAILED;
+ if (prefix_same((struct prefix *)&srp->prefv4, &p)) {
+ new = srp;
+ break;
+ } else {
+ vty_out(vty, "Index %u is already used\n",
+ index);
+ return CMD_WARNING_CONFIG_FAILED;
+ }
}
}
/* Create new Extended Prefix to SRDB if not found */
- new = XCALLOC(MTYPE_OSPF_SR_PARAMS, sizeof(struct sr_prefix));
- IPV4_ADDR_COPY(&new->prefv4.prefix, &p.u.prefix4);
- new->prefv4.prefixlen = p.prefixlen;
- new->prefv4.family = p.family;
- new->sid = index;
- new->type = LOCAL_SID;
+ if (new == NULL) {
+ new = XCALLOC(MTYPE_OSPF_SR_PARAMS, sizeof(struct sr_prefix));
+ IPV4_ADDR_COPY(&new->prefv4.prefix, &p.u.prefix4);
+ new->prefv4.prefixlen = p.prefixlen;
+ new->prefv4.family = p.family;
+ new->sid = index;
+ new->type = LOCAL_SID;
+ }
+
/* Set NO PHP flag if present and compute NHLFE */
if (argv_find(argv, argc, "no-php-flag", &idx)) {
SET_FLAG(new->flags, EXT_SUBTLV_PREFIX_SID_NPFLG);
+ UNSET_FLAG(new->flags, EXT_SUBTLV_PREFIX_SID_EFLG);
new->label_in = index2label(new->sid, OspfSR.self->srgb);
new->nhlfe.label_out = MPLS_LABEL_IMPLICIT_NULL;
}
+ /* Set EXPLICIT NULL flag is present */
+ if (argv_find(argv, argc, "explicit-null", &idx)) {
+ SET_FLAG(new->flags, EXT_SUBTLV_PREFIX_SID_NPFLG);
+ SET_FLAG(new->flags, EXT_SUBTLV_PREFIX_SID_EFLG);
+ }
osr_debug("SR (%s): Add new index %u to Prefix %pFX", __func__, index,
(struct prefix *)&new->prefv4);
}
new->nhlfe.ifindex = ifp->ifindex;
- /* Search if this prefix already exist */
- for (ALL_LIST_ELEMENTS_RO(OspfSR.self->ext_prefix, node, srp)) {
- if ((IPV4_ADDR_SAME(&srp->prefv4.prefix, &p.u.prefix4)
- && srp->prefv4.prefixlen == p.prefixlen))
- break;
- else
- srp = NULL;
- }
-
- /* Update or Add this new SR Prefix */
- if (srp) {
- listnode_delete(OspfSR.self->ext_prefix, srp);
+ /* Add this new SR Prefix if not already found */
+ if (srp != new)
listnode_add(OspfSR.self->ext_prefix, new);
- } else {
- listnode_add(OspfSR.self->ext_prefix, new);
- }
- /* Install Prefix SID if SR is UP */
- if (OspfSR.status == SR_UP)
- ospf_zebra_update_prefix_sid(new);
- else
+ /* Install Prefix SID if SR is UP and a valid input label set */
+ if (OspfSR.status == SR_UP) {
+ if (CHECK_FLAG(new->flags, EXT_SUBTLV_PREFIX_SID_NPFLG)
+ && !CHECK_FLAG(new->flags, EXT_SUBTLV_PREFIX_SID_EFLG))
+ ospf_zebra_update_prefix_sid(new);
+ } else
return CMD_SUCCESS;
/* Finally, update Extended Prefix LSA id SR is UP */
DEFUN (no_sr_prefix_sid,
no_sr_prefix_sid_cmd,
- "no segment-routing prefix A.B.C.D/M [index (0-65535) no-php-flag]",
+ "no segment-routing prefix A.B.C.D/M [index (0-65535)|no-php-flag|explicit-null]",
NO_STR
SR_STR
"Prefix SID\n"
"IPv4 Prefix as A.B.C.D/M\n"
"SID index for this prefix in decimal (0-65535)\n"
"Index value inside SRGB (lower_bound < index < upper_bound)\n"
- "Don't request Penultimate Hop Popping (PHP)\n")
+ "Don't request Penultimate Hop Popping (PHP)\n"
+ "Upstream neighbor must replace prefix-sid with explicit null label\n")
{
int idx = 0;
struct prefix p;
osr_debug("SR (%s): Remove Prefix %pFX with index %u", __func__,
(struct prefix *)&srp->prefv4, srp->sid);
- /* Delete NHLFE if NO-PHP is set */
- if (CHECK_FLAG(srp->flags, EXT_SUBTLV_PREFIX_SID_NPFLG))
+ /* Delete NHLFE if NO-PHP is set and EXPLICIT NULL not set */
+ if (CHECK_FLAG(srp->flags, EXT_SUBTLV_PREFIX_SID_NPFLG)
+ && !CHECK_FLAG(srp->flags, EXT_SUBTLV_PREFIX_SID_EFLG))
ospf_zebra_delete_prefix_sid(srp);
/* OK, all is clean, remove SRP from SRDB */
snprintf(buf, size, "Pop(%u)", label_in);
break;
case MPLS_LABEL_IPV4_EXPLICIT_NULL:
- snprintf(buf, size, "Swap(%u, null)", label_in);
+ if (label_in == MPLS_LABEL_IPV4_EXPLICIT_NULL)
+ snprintf(buf, size, "no-op.");
+ else
+ snprintf(buf, size, "Swap(%u, null)", label_in);
break;
case MPLS_INVALID_LABEL:
snprintf(buf, size, "no-op.");
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