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isis_sr.c
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/*
* This is an implementation of Segment Routing for IS-IS as per RFC 8667
*
* Copyright (C) 2019 Orange http://www.orange.com
*
* Author: Olivier Dugeon <olivier.dugeon@orange.com>
* Contributor: Renato Westphal <renato@opensourcerouting.org> for NetDEF
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; see the file COPYING; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <zebra.h>
#include "if.h"
#include "linklist.h"
#include "log.h"
#include "command.h"
#include "termtable.h"
#include "memory.h"
#include "prefix.h"
#include "table.h"
#include "vty.h"
#include "zclient.h"
#include "lib/lib_errors.h"
#include "isisd/isisd.h"
#include "isisd/isis_spf.h"
#include "isisd/isis_spf_private.h"
#include "isisd/isis_adjacency.h"
#include "isisd/isis_route.h"
#include "isisd/isis_mt.h"
#include "isisd/isis_sr.h"
#include "isisd/isis_tlvs.h"
#include "isisd/isis_misc.h"
#include "isisd/isis_zebra.h"
#include "isisd/isis_errors.h"
/* Local variables and functions */
DEFINE_MTYPE_STATIC(ISISD, ISIS_SR_INFO, "ISIS segment routing information")
static void sr_prefix_uninstall(struct sr_prefix *srp);
static void sr_prefix_reinstall(struct sr_prefix *srp, bool make_before_break);
static void sr_local_block_delete(struct isis_area *area);
static int sr_local_block_init(struct isis_area *area);
static void sr_adj_sid_update(struct sr_adjacency *sra,
struct sr_local_block *srlb);
/* --- RB-Tree Management functions ----------------------------------------- */
/**
* SR Prefix comparison for RB-Tree.
*
* @param a First SR prefix
* @param b Second SR prefix
*
* @return -1 (a < b), 0 (a == b) or +1 (a > b)
*/
static inline int sr_prefix_sid_compare(const struct sr_prefix *a,
const struct sr_prefix *b)
{
return prefix_cmp(&a->prefix, &b->prefix);
}
DECLARE_RBTREE_UNIQ(srdb_node_prefix, struct sr_prefix, node_entry,
sr_prefix_sid_compare)
DECLARE_RBTREE_UNIQ(srdb_area_prefix, struct sr_prefix, area_entry,
sr_prefix_sid_compare)
/**
* Configured SR Prefix comparison for RB-Tree.
*
* @param a First SR prefix
* @param b Second SR prefix
*
* @return -1 (a < b), 0 (a == b) or +1 (a > b)
*/
static inline int sr_prefix_sid_cfg_compare(const struct sr_prefix_cfg *a,
const struct sr_prefix_cfg *b)
{
return prefix_cmp(&a->prefix, &b->prefix);
}
DECLARE_RBTREE_UNIQ(srdb_prefix_cfg, struct sr_prefix_cfg, entry,
sr_prefix_sid_cfg_compare)
/**
* SR Node comparison for RB-Tree.
*
* @param a First SR node
* @param b Second SR node
*
* @return -1 (a < b), 0 (a == b) or +1 (a > b)
*/
static inline int sr_node_compare(const struct sr_node *a,
const struct sr_node *b)
{
return memcmp(a->sysid, b->sysid, ISIS_SYS_ID_LEN);
}
DECLARE_RBTREE_UNIQ(srdb_node, struct sr_node, entry, sr_node_compare)
/* --- Functions used for Yang model and CLI to configure Segment Routing --- */
/**
* Check if prefix correspond to a Node SID.
*
* @param ifp Interface
* @param prefix Prefix to be checked
*
* @return True if the interface/address pair corresponds to a Node-SID
*/
static bool sr_prefix_is_node_sid(const struct interface *ifp,
const struct prefix *prefix)
{
return (if_is_loopback(ifp) && is_host_route(prefix));
}
/**
* Update local SRGB configuration. SRGB is reserved though Label Manager.
* This function trigger the update of local Prefix-SID installation.
*
* @param area IS-IS area
* @param lower_bound Lower bound of SRGB
* @param upper_bound Upper bound of SRGB
*
* @return 0 on success, -1 otherwise
*/
int isis_sr_cfg_srgb_update(struct isis_area *area, uint32_t lower_bound,
uint32_t upper_bound)
{
struct isis_sr_db *srdb = &area->srdb;
sr_debug("ISIS-Sr (%s): Update SRGB with new range [%u/%u]",
area->area_tag, lower_bound, upper_bound);
/* Just store new SRGB values if Label Manager is not available.
* SRGB will be configured later when SR start */
if (!isis_zebra_label_manager_ready()) {
srdb->config.srgb_lower_bound = lower_bound;
srdb->config.srgb_upper_bound = upper_bound;
return 0;
}
/* Label Manager is ready, start by releasing the old SRGB. */
if (srdb->srgb_active) {
isis_zebra_release_label_range(srdb->config.srgb_lower_bound,
srdb->config.srgb_upper_bound);
srdb->srgb_active = false;
}
srdb->config.srgb_lower_bound = lower_bound;
srdb->config.srgb_upper_bound = upper_bound;
if (srdb->enabled) {
struct sr_prefix *srp;
/* then request new SRGB if SR is enabled. */
if (isis_zebra_request_label_range(
srdb->config.srgb_lower_bound,
srdb->config.srgb_upper_bound
- srdb->config.srgb_lower_bound + 1) < 0) {
srdb->srgb_active = false;
return -1;
} else
srdb->srgb_active = true;
sr_debug(" |- Got new SRGB [%u/%u]",
srdb->config.srgb_lower_bound,
srdb->config.srgb_upper_bound);
/* Reinstall local Prefix-SIDs to update their input labels. */
for (int level = ISIS_LEVEL1; level <= ISIS_LEVELS; level++) {
frr_each (srdb_area_prefix,
&area->srdb.prefix_sids[level - 1], srp) {
sr_prefix_reinstall(srp, false);
}
}
lsp_regenerate_schedule(area, area->is_type, 0);
} else if (srdb->config.enabled) {
/* Try to enable SR again using the new SRGB. */
isis_sr_start(area);
}
return 0;
}
/**
* Update Segment Routing Local Block range which is reserved though the
* Label Manager. This function trigger the update of local Adjacency-SID
* installation.
*
* @param area IS-IS area
* @param lower_bound Lower bound of SRLB
* @param upper_bound Upper bound of SRLB
*
* @return 0 on success, -1 otherwise
*/
int isis_sr_cfg_srlb_update(struct isis_area *area, uint32_t lower_bound,
uint32_t upper_bound)
{
struct isis_sr_db *srdb = &area->srdb;
struct listnode *node;
struct sr_adjacency *sra;
sr_debug("ISIS-Sr (%s): Update SRLB with new range [%u/%u]",
area->area_tag, lower_bound, upper_bound);
/* Just store new SRLB values if Label Manager is not available.
* SRLB will be configured later when SR start */
if (!isis_zebra_label_manager_ready()) {
srdb->config.srlb_lower_bound = lower_bound;
srdb->config.srlb_upper_bound = upper_bound;
return 0;
}
/* LM is ready, start by deleting the old SRLB */
sr_local_block_delete(area);
srdb->config.srlb_lower_bound = lower_bound;
srdb->config.srlb_upper_bound = upper_bound;
if (srdb->enabled) {
/* Initialize new SRLB */
if (sr_local_block_init(area) != 0)
return -1;
/* Reinstall local Adjacency-SIDs with new labels. */
for (ALL_LIST_ELEMENTS_RO(area->srdb.adj_sids, node, sra))
sr_adj_sid_update(sra, &srdb->srlb);
/* Update and Flood LSP */
lsp_regenerate_schedule(area, area->is_type, 0);
} else if (srdb->config.enabled) {
/* Try to enable SR again using the new SRLB. */
isis_sr_start(area);
}
return 0;
}
/**
* Add new Prefix-SID configuration to the SRDB.
*
* @param area IS-IS area
* @param prefix Prefix to be added
*
* @return Newly added Prefix-SID configuration structure
*/
struct sr_prefix_cfg *isis_sr_cfg_prefix_add(struct isis_area *area,
const struct prefix *prefix)
{
struct sr_prefix_cfg *pcfg;
struct interface *ifp;
sr_debug("ISIS-Sr (%s): Add local prefix %pFX", area->area_tag, prefix);
pcfg = XCALLOC(MTYPE_ISIS_SR_INFO, sizeof(*pcfg));
pcfg->prefix = *prefix;
pcfg->area = area;
/* Pull defaults from the YANG module. */
pcfg->sid_type = yang_get_default_enum(
"%s/prefix-sid-map/prefix-sid/sid-value-type", ISIS_SR);
pcfg->last_hop_behavior = yang_get_default_enum(
"%s/prefix-sid-map/prefix-sid/last-hop-behavior", ISIS_SR);
/* Set the N-flag when appropriate. */
ifp = if_lookup_prefix(prefix, VRF_DEFAULT);
if (ifp && sr_prefix_is_node_sid(ifp, prefix))
pcfg->node_sid = true;
/* Save prefix-sid configuration. */
srdb_prefix_cfg_add(&area->srdb.config.prefix_sids, pcfg);
return pcfg;
}
/**
* Removal of locally configured Prefix-SID.
*
* @param pcfg Configured Prefix-SID
*/
void isis_sr_cfg_prefix_del(struct sr_prefix_cfg *pcfg)
{
struct isis_area *area = pcfg->area;
sr_debug("ISIS-Sr (%s): Delete local Prefix-SID %pFX %s %u",
area->area_tag, &pcfg->prefix,
pcfg->sid_type == SR_SID_VALUE_TYPE_INDEX ? "index" : "label",
pcfg->sid);
srdb_prefix_cfg_del(&area->srdb.config.prefix_sids, pcfg);
XFREE(MTYPE_ISIS_SR_INFO, pcfg);
}
/**
* Lookup for Prefix-SID in the local configuration.
*
* @param area IS-IS area
* @param prefix Prefix to lookup
*
* @return Configured Prefix-SID structure if found, NULL otherwise
*/
struct sr_prefix_cfg *isis_sr_cfg_prefix_find(struct isis_area *area,
union prefixconstptr prefix)
{
struct sr_prefix_cfg pcfg = {};
prefix_copy(&pcfg.prefix, prefix.p);
return srdb_prefix_cfg_find(&area->srdb.config.prefix_sids, &pcfg);
}
/**
* Fill in Prefix-SID Sub-TLV according to the corresponding configuration.
*
* @param pcfg Prefix-SID configuration
* @param external False if prefix is locally configured, true otherwise
* @param psid Prefix-SID sub-TLV to be updated
*/
void isis_sr_prefix_cfg2subtlv(const struct sr_prefix_cfg *pcfg, bool external,
struct isis_prefix_sid *psid)
{
/* Set SID algorithm. */
psid->algorithm = SR_ALGORITHM_SPF;
/* Set SID flags. */
psid->flags = 0;
switch (pcfg->last_hop_behavior) {
case SR_LAST_HOP_BEHAVIOR_EXP_NULL:
SET_FLAG(psid->flags, ISIS_PREFIX_SID_NO_PHP);
SET_FLAG(psid->flags, ISIS_PREFIX_SID_EXPLICIT_NULL);
break;
case SR_LAST_HOP_BEHAVIOR_NO_PHP:
SET_FLAG(psid->flags, ISIS_PREFIX_SID_NO_PHP);
UNSET_FLAG(psid->flags, ISIS_PREFIX_SID_EXPLICIT_NULL);
break;
case SR_LAST_HOP_BEHAVIOR_PHP:
UNSET_FLAG(psid->flags, ISIS_PREFIX_SID_NO_PHP);
UNSET_FLAG(psid->flags, ISIS_PREFIX_SID_EXPLICIT_NULL);
break;
}
if (external)
SET_FLAG(psid->flags, ISIS_PREFIX_SID_READVERTISED);
if (pcfg->node_sid)
SET_FLAG(psid->flags, ISIS_PREFIX_SID_NODE);
/* Set SID value. */
psid->value = pcfg->sid;
if (pcfg->sid_type == SR_SID_VALUE_TYPE_ABSOLUTE) {
SET_FLAG(psid->flags, ISIS_PREFIX_SID_VALUE);
SET_FLAG(psid->flags, ISIS_PREFIX_SID_LOCAL);
}
}
/* --- Segment Routing Prefix Management functions -------------------------- */
/**
* Add Segment Routing Prefix to a given Segment Routing Node.
*
* @param area IS-IS area
* @param srn Segment Routing Node
* @param prefix Prefix to be added
* @param local True if prefix is locally configured, false otherwise
* @param psid Prefix-SID sub-TLVs
*
* @return New Segment Routing Prefix structure
*/
static struct sr_prefix *sr_prefix_add(struct isis_area *area,
struct sr_node *srn,
union prefixconstptr prefix, bool local,
const struct isis_prefix_sid *psid)
{
struct sr_prefix *srp;
srp = XCALLOC(MTYPE_ISIS_SR_INFO, sizeof(*srp));
prefix_copy(&srp->prefix, prefix.p);
srp->sid = *psid;
srp->input_label = MPLS_INVALID_LABEL;
if (local) {
srp->type = ISIS_SR_PREFIX_LOCAL;
isis_sr_nexthop_reset(&srp->u.local.info);
} else {
srp->type = ISIS_SR_PREFIX_REMOTE;
srp->u.remote.rinfo = NULL;
}
srp->srn = srn;
srdb_node_prefix_add(&srn->prefix_sids, srp);
/* TODO: this might fail if we have Anycast SIDs in the IS-IS area. */
srdb_area_prefix_add(&area->srdb.prefix_sids[srn->level - 1], srp);
sr_debug(" |- Added new SR Prefix-SID %pFX %s %u to SR Node %s",
&srp->prefix, IS_SID_VALUE(srp->sid.flags) ? "label" : "index",
srp->sid.value, sysid_print(srn->sysid));
return srp;
}
/**
* Remove given Segment Prefix from given Segment Routing Node.
* Prefix-SID is un-installed first.
*
* @param area IS-IS area
* @param srn Segment Routing Node
* @param srp Segment Routing Prefix
*/
static void sr_prefix_del(struct isis_area *area, struct sr_node *srn,
struct sr_prefix *srp)
{
sr_debug(" |- Delete SR Prefix-SID %pFX %s %u to SR Node %s",
&srp->prefix, IS_SID_VALUE(srp->sid.flags) ? "label" : "index",
srp->sid.value, sysid_print(srn->sysid));
sr_prefix_uninstall(srp);
srdb_node_prefix_del(&srn->prefix_sids, srp);
srdb_area_prefix_del(&area->srdb.prefix_sids[srn->level - 1], srp);
XFREE(MTYPE_ISIS_SR_INFO, srp);
}
/**
* Find Segment Routing Prefix by Area.
*
* @param area IS-IS area
* @param level IS-IS level
* @param prefix Prefix to lookup
*
* @return Segment Routing Prefix structure if found, NULL otherwise
*/
static struct sr_prefix *sr_prefix_find_by_area(struct isis_area *area,
int level,
union prefixconstptr prefix)
{
struct sr_prefix srp = {};
prefix_copy(&srp.prefix, prefix.p);
return srdb_area_prefix_find(&area->srdb.prefix_sids[level - 1], &srp);
}
/**
* Find Segment Routing Prefix by Segment Routing Node.
*
* @param srn Segment Routing Node
* @param prefix Prefix to lookup
*
* @return Segment Routing Prefix structure if found, NULL otherwise
*/
static struct sr_prefix *sr_prefix_find_by_node(struct sr_node *srn,
union prefixconstptr prefix)
{
struct sr_prefix srp = {};
prefix_copy(&srp.prefix, prefix.p);
return srdb_node_prefix_find(&srn->prefix_sids, &srp);
}
/* --- Segment Routing Node Management functions ---------------------------- */
/**
* Add Segment Routing Node to the Segment Routing Data Base.
*
* @param area IS-IS area
* @param level IS-IS level
* @param sysid Node System ID
* @param cap Segment Routing Capability sub-TLVs
*
* @return New Segment Routing Node structure
*/
static struct sr_node *sr_node_add(struct isis_area *area, int level,
const uint8_t *sysid)
{
struct sr_node *srn;
srn = XCALLOC(MTYPE_ISIS_SR_INFO, sizeof(*srn));
srn->level = level;
memcpy(srn->sysid, sysid, ISIS_SYS_ID_LEN);
srn->area = area;
srdb_node_prefix_init(&srn->prefix_sids);
srdb_node_add(&area->srdb.sr_nodes[level - 1], srn);
sr_debug(" |- Added new SR Node %s", sysid_print(srn->sysid));
return srn;
}
static void sr_node_del(struct isis_area *area, int level, struct sr_node *srn)
/**
* Remove Segment Routing Node from the Segment Routing Data Base.
* All Prefix-SID attached to this Segment Routing Node are removed first.
*
* @param area IS-IS area
* @param level IS-IS level
* @param srn Segment Routing Node to be deleted
*/
{
sr_debug(" |- Delete SR Node %s", sysid_print(srn->sysid));
/* Remove and uninstall Prefix-SIDs. */
while (srdb_node_prefix_count(&srn->prefix_sids) > 0) {
struct sr_prefix *srp;
srp = srdb_node_prefix_first(&srn->prefix_sids);
sr_prefix_del(area, srn, srp);
}
srdb_node_del(&area->srdb.sr_nodes[level - 1], srn);
XFREE(MTYPE_ISIS_SR_INFO, srn);
}
/**
* Find Segment Routing Node in the Segment Routing Data Base per system ID.
*
* @param area IS-IS area
* @param level IS-IS level
* @param sysid Node System ID to lookup
*
* @return Segment Routing Node structure if found, NULL otherwise
*/
static struct sr_node *sr_node_find(struct isis_area *area, int level,
const uint8_t *sysid)
{
struct sr_node srn = {};
memcpy(srn.sysid, sysid, ISIS_SYS_ID_LEN);
return srdb_node_find(&area->srdb.sr_nodes[level - 1], &srn);
}
/**
* Update Segment Routing Node following an SRGB update. This function
* is called when a neighbor SR Node has updated its SRGB.
*
* @param area IS-IS area
* @param level IS-IS level
* @param sysid Segment Routing Node system ID
*/
static void sr_node_srgb_update(struct isis_area *area, int level,
uint8_t *sysid)
{
struct sr_prefix *srp;
sr_debug("ISIS-Sr (%s): Update neighbors SR Node with new SRGB",
area->area_tag);
frr_each (srdb_area_prefix, &area->srdb.prefix_sids[level - 1], srp) {
struct listnode *node;
struct isis_nexthop *nh;
if (srp->type == ISIS_SR_PREFIX_LOCAL)
continue;
if (srp->u.remote.rinfo == NULL)
continue;
for (ALL_LIST_ELEMENTS_RO(srp->u.remote.rinfo->nexthops, node,
nh)) {
if (memcmp(nh->sysid, sysid, ISIS_SYS_ID_LEN) != 0)
continue;
/*
* The Prefix-SID input label hasn't changed. We could
* re-install all Prefix-SID with "Make Before Break"
* option. Zebra layer will update output label(s) by
* adding new entry before removing the old one(s).
*/
sr_prefix_reinstall(srp, true);
break;
}
}
}
/* --- Segment Routing Nexthop information Management functions ------------- */
/**
* Update Segment Routing Nexthop.
*
* @param srnh Segment Routing next hop
* @param label Output MPLS label
*/
void isis_sr_nexthop_update(struct sr_nexthop_info *srnh, mpls_label_t label)
{
srnh->label = label;
if (srnh->uptime == 0)
srnh->uptime = time(NULL);
}
/**
* Reset Segment Routing Nexthop.
*
* @param srnh Segment Routing Nexthop
*/
void isis_sr_nexthop_reset(struct sr_nexthop_info *srnh)
{
srnh->label = MPLS_INVALID_LABEL;
srnh->uptime = 0;
}
/* --- Segment Routing Prefix-SID Management functions to configure LFIB ---- */
/**
* Lookup IS-IS route in the Shortest Path Tree.
*
* @param area IS-IS area
* @param tree_id Shortest Path Tree identifier
* @param srp Segment Routing Prefix to lookup
*
* @return Route Information for this prefix if found, NULL otherwise
*/
static struct isis_route_info *sr_prefix_lookup_route(struct isis_area *area,
enum spf_tree_id tree_id,
struct sr_prefix *srp)
{
struct route_node *rn;
int level = srp->srn->level;
rn = route_node_lookup(area->spftree[tree_id][level - 1]->route_table,
&srp->prefix);
if (rn) {
route_unlock_node(rn);
if (rn->info)
return rn->info;
}
return NULL;
}
/**
* Compute input label for the given Prefix-SID.
*
* @param srp Segment Routing Prefix
*
* @return MPLS label or MPLS_INVALID_LABEL in case of SRGB overflow
*/
static mpls_label_t sr_prefix_in_label(const struct sr_prefix *srp)
{
const struct sr_node *srn = srp->srn;
struct isis_area *area = srn->area;
/* Return SID value as MPLS label if it is an Absolute SID */
if (CHECK_FLAG(srp->sid.flags,
ISIS_PREFIX_SID_VALUE | ISIS_PREFIX_SID_LOCAL))
return srp->sid.value;
/* Check that SID index falls inside the SRGB */
if (srp->sid.value >= (area->srdb.config.srgb_upper_bound
- area->srdb.config.srgb_lower_bound + 1)) {
flog_warn(EC_ISIS_SID_OVERFLOW,
"%s: SID index %u falls outside local SRGB range",
__func__, srp->sid.value);
return MPLS_INVALID_LABEL;
}
/* Return MPLS label as SID index + SRGB_lower_bound as per RFC 8667 */
return (area->srdb.config.srgb_lower_bound + srp->sid.value);
}
/**
* Compute output label for the given Prefix-SID.
*
* @param srp Segment Routing Prefix
* @param srn_nexthop Segment Routing nexthop node
* @param sysid System ID of the SR node which advertised the Prefix-SID
*
* @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 *srn_nexthop,
const uint8_t *sysid)
{
const struct sr_node *srn = srp->srn;
/* Check if the nexthop SR Node is the last hop? */
if (memcmp(sysid, srn->sysid, ISIS_SYS_ID_LEN) == 0) {
/* SR-Node doesn't request NO-PHP. Return Implicit NULL label */
if (!CHECK_FLAG(srp->sid.flags, ISIS_PREFIX_SID_NO_PHP))
return MPLS_LABEL_IMPLICIT_NULL;
/* SR-Node requests Implicit NULL Label */
if (CHECK_FLAG(srp->sid.flags, ISIS_PREFIX_SID_EXPLICIT_NULL)) {
if (srp->prefix.family == AF_INET)
return MPLS_LABEL_IPV4_EXPLICIT_NULL;
else
return MPLS_LABEL_IPV6_EXPLICIT_NULL;
}
/* Fallthrough */
}
/* Return SID value as MPLS label if it is an Absolute SID */
if (CHECK_FLAG(srp->sid.flags,
ISIS_PREFIX_SID_VALUE | ISIS_PREFIX_SID_LOCAL)) {
/*
* V/L SIDs have local significance, so only adjacent routers
* can use them (RFC8667 section #2.1.1.1)
*/
if (srp->srn != srn_nexthop)
return MPLS_INVALID_LABEL;
return srp->sid.value;
}
/* Check that SID index falls inside the SRGB */
if (srp->sid.value >= srn_nexthop->cap.srgb.range_size) {
flog_warn(EC_ISIS_SID_OVERFLOW,
"%s: SID index %u falls outside remote SRGB range",
__func__, srp->sid.value);
return MPLS_INVALID_LABEL;
}
/* Return MPLS label as SID index + SRGB_lower_bound as per RFC 8667 */
return (srn_nexthop->cap.srgb.lower_bound + srp->sid.value);
}
/**
* Process local Prefix-SID and install it if possible. Input label is
* computed before installing it in LFIB.
*
* @param srp Segment Routing Prefix
*
* @return 0 on success, -1 otherwise
*/
static int sr_prefix_install_local(struct sr_prefix *srp)
{
mpls_label_t input_label;
const struct sr_node *srn = srp->srn;
/*
* No need to install Label for local Prefix-SID unless the
* no-PHP option is configured.
*/
if (!CHECK_FLAG(srp->sid.flags, ISIS_PREFIX_SID_NO_PHP)
|| CHECK_FLAG(srp->sid.flags, ISIS_PREFIX_SID_EXPLICIT_NULL))
return -1;
sr_debug(" |- Installing Prefix-SID %pFX %s %u (%s) with nexthop self",
&srp->prefix, IS_SID_VALUE(srp->sid.flags) ? "label" : "index",
srp->sid.value, circuit_t2string(srn->level));
/* Compute input label and check that is valid. */
input_label = sr_prefix_in_label(srp);
if (input_label == MPLS_INVALID_LABEL)
return -1;
/* Update internal state. */
srp->input_label = input_label;
isis_sr_nexthop_update(&srp->u.local.info, MPLS_LABEL_IMPLICIT_NULL);
/* Install Prefix-SID in the forwarding plane. */
isis_zebra_send_prefix_sid(ZEBRA_MPLS_LABELS_REPLACE, srp);
return 0;
}
/**
* Process remote Prefix-SID and install it if possible. Input and Output
* labels are computed before installing them in LFIB.
*
* @param srp Segment Routing Prefix
*
* @return 0 on success, -1 otherwise
*/
static int sr_prefix_install_remote(struct sr_prefix *srp)
{
const struct sr_node *srn = srp->srn;
struct isis_area *area = srn->area;
enum spf_tree_id tree_id;
struct listnode *node;
struct isis_nexthop *nexthop;
mpls_label_t input_label;
size_t nexthop_num = 0;
/* Lookup to associated IS-IS route. */
tree_id = (srp->prefix.family == AF_INET) ? SPFTREE_IPV4 : SPFTREE_IPV6;
srp->u.remote.rinfo = sr_prefix_lookup_route(area, tree_id, srp);
if (!srp->u.remote.rinfo)
/* SPF hasn't converged for this route yet. */
return -1;
/* Compute input label and check that is valid. */
input_label = sr_prefix_in_label(srp);
if (input_label == MPLS_INVALID_LABEL)
return -1;
sr_debug(" |- Installing Prefix-SID %pFX %s %u (%s)", &srp->prefix,
IS_SID_VALUE(srp->sid.flags) ? "label" : "index",
srp->sid.value, circuit_t2string(srn->level));
/* Process all SPF nexthops */
for (ALL_LIST_ELEMENTS_RO(srp->u.remote.rinfo->nexthops, node,
nexthop)) {
struct sr_node *srn_nexthop;
mpls_label_t output_label;
/* Check if the nexthop advertised a SRGB. */
srn_nexthop = sr_node_find(area, srn->level, nexthop->sysid);
if (!srn_nexthop)
goto next;
/*
* Check if the nexthop can handle SR-MPLS encapsulated IPv4 or
* IPv6 packets.
*/
if ((nexthop->family == AF_INET
&& !IS_SR_IPV4(srn_nexthop->cap.srgb))
|| (nexthop->family == AF_INET6
&& !IS_SR_IPV6(srn_nexthop->cap.srgb)))
goto next;
/* Compute output label and check if it is valid */
output_label =
sr_prefix_out_label(srp, srn_nexthop, nexthop->sysid);
if (output_label == MPLS_INVALID_LABEL)
goto next;
if (IS_DEBUG_SR) {
static char buf[INET6_ADDRSTRLEN];
inet_ntop(nexthop->family, &nexthop->ip, buf,
sizeof(buf));
zlog_debug(" |- nexthop %s label %u", buf,
output_label);
}
isis_sr_nexthop_update(&nexthop->sr, output_label);
nexthop_num++;
continue;
next:
isis_sr_nexthop_reset(&nexthop->sr);
}
/* Check that we found at least one valid nexthop */
if (nexthop_num == 0) {
sr_debug(" |- no valid nexthops");
return -1;
}
/* Update internal state. */
srp->input_label = input_label;
/* Install Prefix-SID in the forwarding plane. */
isis_zebra_send_prefix_sid(ZEBRA_MPLS_LABELS_REPLACE, srp);
return 0;
}
/**
* Process local or remote Prefix-SID and install it if possible.
*
* @param srp Segment Routing Prefix
*/
static void sr_prefix_install(struct sr_prefix *srp)
{
const struct sr_node *srn = srp->srn;
struct isis_area *area = srn->area;
int ret;
sr_debug("ISIS-Sr (%s): Install Prefix-SID %pFX %s %u", area->area_tag,
&srp->prefix, IS_SID_VALUE(srp->sid.flags) ? "label" : "index",
srp->sid.value);
/* L1 routes are preferred over the L2 ones. */
if (area->is_type == IS_LEVEL_1_AND_2) {
struct sr_prefix *srp_l1, *srp_l2;
switch (srn->level) {
case ISIS_LEVEL1:
srp_l2 = sr_prefix_find_by_area(area, ISIS_LEVEL2,
&srp->prefix);
if (srp_l2)
sr_prefix_uninstall(srp_l2);
break;
case ISIS_LEVEL2:
srp_l1 = sr_prefix_find_by_area(area, ISIS_LEVEL1,
&srp->prefix);
if (srp_l1)
return;
break;
default:
break;
}
}
/* Install corresponding LFIB entry */
if (srp->type == ISIS_SR_PREFIX_LOCAL)
ret = sr_prefix_install_local(srp);
else
ret = sr_prefix_install_remote(srp);
if (ret != 0)
sr_prefix_uninstall(srp);
}
/**
* Uninstall local or remote Prefix-SID.
*
* @param srp Segment Routing Prefix
*/
static void sr_prefix_uninstall(struct sr_prefix *srp)
{
struct listnode *node;
struct isis_nexthop *nexthop;
/* Check that Input Label is valid */
if (srp->input_label == MPLS_INVALID_LABEL)
return;
sr_debug("ISIS-Sr: Un-install Prefix-SID %pFX %s %u", &srp->prefix,
IS_SID_VALUE(srp->sid.flags) ? "label" : "index",
srp->sid.value);
/* Uninstall Prefix-SID from the forwarding plane. */
isis_zebra_send_prefix_sid(ZEBRA_MPLS_LABELS_DELETE, srp);
/* Reset internal state. */
srp->input_label = MPLS_INVALID_LABEL;
switch (srp->type) {
case ISIS_SR_PREFIX_LOCAL:
isis_sr_nexthop_reset(&srp->u.local.info);
break;
case ISIS_SR_PREFIX_REMOTE:
if (srp->u.remote.rinfo) {
for (ALL_LIST_ELEMENTS_RO(srp->u.remote.rinfo->nexthops,
node, nexthop))
isis_sr_nexthop_reset(&nexthop->sr);
}
break;
}
}
/**
* Reinstall local or remote Prefix-SID.
*
* @param srp Segment Routing Prefix
*/
static inline void sr_prefix_reinstall(struct sr_prefix *srp,
bool make_before_break)
{
/*
* Make Before Break can be used only when we know for sure that
* the Prefix-SID input label hasn't changed. Otherwise we need to
* uninstall the Prefix-SID first using the old input label before
* reinstalling it.
*/
if (!make_before_break)
sr_prefix_uninstall(srp);
/* New input label is computed in sr_prefix_install() function */
sr_prefix_install(srp);
}
/* --- IS-IS LSP Parse functions -------------------------------------------- */
/**
* Compare Router Capabilities. Only Flags, SRGB and Algorithm are used for the
* comparison. MSD and SRLB modification must not trigger and SR-Prefix update.
*
* @param r1 First Router Capabilities to compare
* @param r2 Second Router Capabilities to compare
* @return 0 if r1 and r2 are equal or -1 otherwise
*/
static int router_cap_cmp(const struct isis_router_cap *r1,
const struct isis_router_cap *r2)
{
if (r1->flags == r2->flags
&& r1->srgb.lower_bound == r2->srgb.lower_bound
&& r1->srgb.range_size == r2->srgb.range_size
&& r1->algo[0] == r2->algo[0])
return 0;
else
return -1;
}
/**
* Parse all SR-related information from the given Router Capabilities TLV.
*
* @param area IS-IS area
* @param level IS-IS level
* @param sysid System ID of the LSP
* @param router_cap Router Capability subTLVs
*
* @return Segment Routing Node structure for this System ID
*/
static struct sr_node *
parse_router_cap_tlv(struct isis_area *area, int level, const uint8_t *sysid,
const struct isis_router_cap *router_cap)
{
struct sr_node *srn;
if (!router_cap || router_cap->srgb.range_size == 0)
return NULL;
sr_debug("ISIS-Sr (%s): Parse Router Capability TLV", area->area_tag);
srn = sr_node_find(area, level, sysid);