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ospfd: Modifying LSID generation algorithm

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Description:
	This LSID alogithm added as per rcf2328 Appendex-E recommendation.
	This applies only for AS-external lsas and summary lsas.

	As an example of the algorithm, consider its operation when the
        following sequence of events occurs in a single router (Router A).

        (1) Router A wants to originate an AS-external-LSA for
            [10.0.0.0,255.255.255.0]:

            (a) A Link State ID of 10.0.0.0 is used.

        (2) Router A then wants to originate an AS-external-LSA for
            [10.0.0.0,255.255.0.0]:

            (a) The LSA for [10.0.0,0,255.255.255.0] is reoriginated using a
                new Link State ID of 10.0.0.255.

            (b) A Link State ID of 10.0.0.0 is used for
                [10.0.0.0,255.255.0.0].

        (3) Router A then wants to originate an AS-external-LSA for
            [10.0.0.0,255.0.0.0]:
            (a) The LSA for [10.0.0.0,255.255.0.0] is reoriginated using a
                new Link State ID of 10.0.255.255.

            (b) A Link State ID of 10.0.0.0 is used for
                [10.0.0.0,255.0.0.0].

            (c) The network [10.0.0.0,255.255.255.0] keeps its Link State ID
                of 10.0.0.255.

Signed-off-by: Rajesh Girada <rgirada@vmware.com>
This commit is contained in:
rgirada 2022-01-05 09:45:33 -08:00
parent 9e84443aca
commit a8c22275fe
3 changed files with 321 additions and 101 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
ospfd/ospf_asbr.c
View File

@ -223,8 +223,15 @@ struct ospf_lsa *ospf_external_info_find_lsa(struct ospf *ospf,
id.s_addr = p->prefix.s_addr | (~mask.s_addr);
lsa = ospf_lsdb_lookup_by_id(ospf->lsdb, OSPF_AS_EXTERNAL_LSA, id,
ospf->router_id);
if (lsa)
if (lsa) {
if (p->prefixlen == IPV4_MAX_BITLEN) {
al = (struct as_external_lsa *)lsa->data;
if (mask.s_addr != al->mask.s_addr)
return NULL;
}
return lsa;
}
lsa = ospf_lsdb_lookup_by_id(ospf->lsdb, OSPF_AS_EXTERNAL_LSA,
p->prefix, ospf->router_id);

405
ospfd/ospf_lsa.c
View File

@ -53,6 +53,29 @@
#include "ospfd/ospf_abr.h"
#include "ospfd/ospf_errors.h"
static struct ospf_lsa *ospf_handle_summarylsa_lsId_chg(struct ospf *ospf,
struct prefix_ipv4 *p,
uint8_t type,
uint32_t metric,
struct in_addr old_id);
static struct ospf_lsa *
ospf_summary_lsa_prepare_and_flood(struct prefix_ipv4 *p, uint32_t metric,
struct ospf_area *area, struct in_addr id);
static struct ospf_lsa *ospf_summary_lsa_refresh(struct ospf *ospf,
struct ospf_lsa *lsa);
static struct ospf_lsa *
ospf_asbr_summary_lsa_prepare_and_flood(struct prefix_ipv4 *p, uint32_t metric,
struct ospf_area *area,
struct in_addr id);
static struct ospf_lsa *ospf_summary_asbr_lsa_refresh(struct ospf *ospf,
struct ospf_lsa *lsa);
static struct ospf_lsa *ospf_handle_exnl_lsa_lsId_chg(struct ospf *ospf,
struct external_info *ei,
struct in_addr id);
static struct ospf_lsa *
ospf_exnl_lsa_prepare_and_flood(struct ospf *ospf, struct external_info *ei,
struct in_addr id);
uint32_t get_metric(uint8_t *metric)
{
uint32_t m;
@ -1221,31 +1244,11 @@ static struct ospf_lsa *ospf_summary_lsa_new(struct ospf_area *area,
}
/* Originate Summary-LSA. */
struct ospf_lsa *ospf_summary_lsa_originate(struct prefix_ipv4 *p,
uint32_t metric,
struct ospf_area *area)
static struct ospf_lsa *
ospf_summary_lsa_prepare_and_flood(struct prefix_ipv4 *p, uint32_t metric,
struct ospf_area *area, struct in_addr id)
{
struct ospf_lsa *new;
struct in_addr id;
if (area->ospf->gr_info.restart_in_progress) {
if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
zlog_debug(
"LSA[Type%d]: Graceful Restart in progress, don't originate",
OSPF_SUMMARY_LSA);
return NULL;
}
id = ospf_lsa_unique_id(area->ospf, area->lsdb, OSPF_SUMMARY_LSA, p);
if (id.s_addr == 0xffffffff) {
/* Maybe Link State ID not available. */
if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
zlog_debug(
"LSA[Type%d]: Link ID not available, can't originate",
OSPF_SUMMARY_LSA);
return NULL;
}
/* Create new summary-LSA instance. */
if (!(new = ospf_summary_lsa_new(area, (struct prefix *)p, metric, id)))
@ -1270,6 +1273,97 @@ struct ospf_lsa *ospf_summary_lsa_originate(struct prefix_ipv4 *p,
return new;
}
static struct ospf_lsa *ospf_handle_summarylsa_lsId_chg(struct ospf *ospf,
struct prefix_ipv4 *p,
uint8_t type,
uint32_t metric,
struct in_addr old_id)
{
struct ospf_lsa *lsa = NULL;
struct ospf_lsa *new = NULL;
struct summary_lsa *sl = NULL;
struct ospf_area *old_area = NULL;
struct prefix_ipv4 old_prefix;
uint32_t old_metric;
struct in_addr mask;
uint32_t metric_val;
char *metric_buf;
lsa = ospf_lsdb_lookup_by_id(ospf->lsdb, type, p->prefix,
ospf->router_id);
if (!lsa) {
flog_warn(EC_OSPF_LSA_NULL, "(%s): LSA not found", __func__);
return NULL;
}
sl = (struct summary_lsa *)lsa->data;
old_area = lsa->area;
old_metric = GET_METRIC(sl->metric);
old_prefix.prefix = sl->header.id;
old_prefix.prefixlen = ip_masklen(sl->mask);
old_prefix.family = AF_INET;
/* change the mask */
masklen2ip(p->prefixlen, &mask);
sl->mask.s_addr = mask.s_addr;
/* Copy the metric*/
metric_val = htonl(metric);
metric_buf = (char *)&metric_val;
memcpy(sl->metric, metric_buf, sizeof(metric_val));
if (type == OSPF_SUMMARY_LSA) {
/*Refresh the LSA with new LSA*/
ospf_summary_lsa_refresh(ospf, lsa);
new = ospf_summary_lsa_prepare_and_flood(
&old_prefix, old_metric, old_area, old_id);
} else {
/*Refresh the LSA with new LSA*/
ospf_summary_asbr_lsa_refresh(ospf, lsa);
new = ospf_asbr_summary_lsa_prepare_and_flood(
&old_prefix, old_metric, old_area, old_id);
}
return new;
}
/* Originate Summary-LSA. */
struct ospf_lsa *ospf_summary_lsa_originate(struct prefix_ipv4 *p,
uint32_t metric,
struct ospf_area *area)
{
struct in_addr id;
enum lsid_status status;
struct ospf_lsa *new = NULL;
status = ospf_lsa_unique_id(area->ospf, area->lsdb, OSPF_SUMMARY_LSA, p,
&id);
if (status == LSID_CHANGE) {
if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
zlog_debug("Link ID has to be changed.");
new = ospf_handle_summarylsa_lsId_chg(
area->ospf, p, OSPF_SUMMARY_LSA, metric, id);
return new;
} else if (status == LSID_NOT_AVAILABLE) {
/* Link State ID not available. */
if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
zlog_debug(
"LSA[Type5]: Link ID not available, can't originate");
return NULL;
}
new = ospf_summary_lsa_prepare_and_flood(p, metric, area, id);
return new;
}
static struct ospf_lsa *ospf_summary_lsa_refresh(struct ospf *ospf,
struct ospf_lsa *lsa)
{
@ -1370,32 +1464,12 @@ static struct ospf_lsa *ospf_summary_asbr_lsa_new(struct ospf_area *area,
}
/* Originate summary-ASBR-LSA. */
struct ospf_lsa *ospf_summary_asbr_lsa_originate(struct prefix_ipv4 *p,
uint32_t metric,
struct ospf_area *area)
static struct ospf_lsa *
ospf_asbr_summary_lsa_prepare_and_flood(struct prefix_ipv4 *p, uint32_t metric,
struct ospf_area *area,
struct in_addr id)
{
struct ospf_lsa *new;
struct in_addr id;
if (area->ospf->gr_info.restart_in_progress) {
if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
zlog_debug(
"LSA[Type%d]: Graceful Restart in progress, don't originate",
OSPF_ASBR_SUMMARY_LSA);
return NULL;
}
id = ospf_lsa_unique_id(area->ospf, area->lsdb, OSPF_ASBR_SUMMARY_LSA,
p);
if (id.s_addr == 0xffffffff) {
/* Maybe Link State ID not available. */
if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
zlog_debug(
"LSA[Type%d]: Link ID not available, can't originate",
OSPF_ASBR_SUMMARY_LSA);
return NULL;
}
/* Create new summary-LSA instance. */
new = ospf_summary_asbr_lsa_new(area, (struct prefix *)p, metric, id);
@ -1421,6 +1495,37 @@ struct ospf_lsa *ospf_summary_asbr_lsa_originate(struct prefix_ipv4 *p,
return new;
}
struct ospf_lsa *ospf_summary_asbr_lsa_originate(struct prefix_ipv4 *p,
uint32_t metric,
struct ospf_area *area)
{
struct ospf_lsa *new;
struct in_addr id;
enum lsid_status status;
status = ospf_lsa_unique_id(area->ospf, area->lsdb,
OSPF_ASBR_SUMMARY_LSA, p, &id);
if (status == LSID_CHANGE) {
if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
zlog_debug("Link ID has to be changed.");
new = ospf_handle_summarylsa_lsId_chg(
area->ospf, p, OSPF_ASBR_SUMMARY_LSA, metric, id);
return new;
} else if (status == LSID_NOT_AVAILABLE) {
/* Link State ID not available. */
if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
zlog_debug(
"LSA[Type5]: Link ID not available, can't originate");
return NULL;
}
new = ospf_asbr_summary_lsa_prepare_and_flood(p, metric, area, id);
return new;
}
static struct ospf_lsa *ospf_summary_asbr_lsa_refresh(struct ospf *ospf,
struct ospf_lsa *lsa)
{
@ -1612,42 +1717,15 @@ static void ospf_external_lsa_body_set(struct stream *s,
}
/* Create new external-LSA. */
static struct ospf_lsa *ospf_external_lsa_new(struct ospf *ospf,
struct external_info *ei,
struct in_addr *old_id)
static struct ospf_lsa *
ospf_exnl_lsa_prepare_and_flood(struct ospf *ospf, struct external_info *ei,
struct in_addr id)
{
struct stream *s;
struct lsa_header *lsah;
struct ospf_lsa *new;
struct in_addr id;
int length;
if (ei == NULL) {
if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
zlog_debug(
"LSA[Type5]: External info is NULL, can't originate");
return NULL;
}
if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
zlog_debug("LSA[Type5]: Originate AS-external-LSA instance");
/* If old Link State ID is specified, refresh LSA with same ID. */
if (old_id)
id = *old_id;
/* Get Link State with unique ID. */
else {
id = ospf_lsa_unique_id(ospf, ospf->lsdb, OSPF_AS_EXTERNAL_LSA,
&ei->p);
if (id.s_addr == 0xffffffff) {
/* Maybe Link State ID not available. */
if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
zlog_debug(
"LSA[Type5]: Link ID not available, can't originate");
return NULL;
}
}
/* Create new stream for LSA. */
s = stream_new(OSPF_MAX_LSA_SIZE);
lsah = (struct lsa_header *)STREAM_DATA(s);
@ -1677,6 +1755,99 @@ static struct ospf_lsa *ospf_external_lsa_new(struct ospf *ospf,
return new;
}
static struct ospf_lsa *ospf_handle_exnl_lsa_lsId_chg(struct ospf *ospf,
struct external_info *ei,
struct in_addr id)
{
struct ospf_lsa *lsa;
struct as_external_lsa *al;
struct in_addr mask;
struct ospf_lsa *new;
struct external_info ei_summary;
struct external_info *ei_old;
lsa = ospf_lsdb_lookup_by_id(ospf->lsdb, OSPF_AS_EXTERNAL_LSA,
ei->p.prefix, ospf->router_id);
if (!lsa) {
flog_warn(EC_OSPF_LSA_NULL, "(%s): LSA not found", __func__);
return NULL;
}
ei_old = ospf_external_info_check(ospf, lsa);
al = (struct as_external_lsa *)lsa->data;
if (!ei_old) {
/* eii_old pointer of LSA is NULL, this
* must be external aggregate route.
*/
ei_summary.p.family = AF_INET;
ei_summary.p.prefix = al->header.id;
ei_summary.p.prefixlen = ip_masklen(al->mask);
ei_summary.tag = (unsigned long)ntohl(al->e[0].route_tag);
ei_old = &ei_summary;
}
/* change the mask */
masklen2ip(ei->p.prefixlen, &mask);
al->mask.s_addr = mask.s_addr;
/*Refresh the LSA with new LSA*/
ospf_external_lsa_refresh(ospf, lsa, ei, LSA_REFRESH_FORCE, 0);
/*Originate the old LSA with changed LSID*/
new = ospf_exnl_lsa_prepare_and_flood(ospf, ei_old, id);
return new;
}
static struct ospf_lsa *ospf_external_lsa_new(struct ospf *ospf,
struct external_info *ei,
struct in_addr *old_id)
{
struct ospf_lsa *new;
struct in_addr id;
enum lsid_status status;
if (ei == NULL) {
if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
zlog_debug(
"LSA[Type5]: External info is NULL, can't originate");
return NULL;
}
if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
zlog_debug("LSA[Type5]: Originate AS-external-LSA instance");
/* If old Link State ID is specified, refresh LSA with same ID. */
if (old_id)
id = *old_id;
/* Get Link State with unique ID. */
else {
status = ospf_lsa_unique_id(ospf, ospf->lsdb,
OSPF_AS_EXTERNAL_LSA, &ei->p, &id);
if (status == LSID_CHANGE) {
if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
zlog_debug("Link ID has to be changed.");
new = ospf_handle_exnl_lsa_lsId_chg(ospf, ei, id);
return new;
} else if (status == LSID_NOT_AVAILABLE) {
/* Link State ID not available. */
if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
zlog_debug(
"LSA[Type5]: Link ID not available, can't originate");
return NULL;
}
}
new = ospf_exnl_lsa_prepare_and_flood(ospf, ei, id);
return new;
}
/* As Type-7 */
static void ospf_install_flood_nssa(struct ospf *ospf, struct ospf_lsa *lsa,
struct external_info *ei)
@ -3510,49 +3681,87 @@ int ospf_lsa_is_self_originated(struct ospf *ospf, struct ospf_lsa *lsa)
}
/* Get unique Link State ID. */
struct in_addr ospf_lsa_unique_id(struct ospf *ospf, struct ospf_lsdb *lsdb,
uint8_t type, struct prefix_ipv4 *p)
enum lsid_status ospf_lsa_unique_id(struct ospf *ospf, struct ospf_lsdb *lsdb,
uint8_t type, struct prefix_ipv4 *p,
struct in_addr *id)
{
struct ospf_lsa *lsa;
struct in_addr mask, id;
struct in_addr mask;
id = p->prefix;
*id = p->prefix;
/* Check existence of LSA instance. */
lsa = ospf_lsdb_lookup_by_id(lsdb, type, id, ospf->router_id);
lsa = ospf_lsdb_lookup_by_id(lsdb, type, *id, ospf->router_id);
if (lsa) {
struct as_external_lsa *al =
(struct as_external_lsa *)lsa->data;
/* Ref rfc2328,Appendex E.1
* If router already originated the external lsa with lsid
* as the current prefix, and the masklens are same then
* terminate the LSID algorithem.
*/
if (ip_masklen(al->mask) == p->prefixlen) {
if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
zlog_debug(
"ospf_lsa_unique_id(): Can't get Link State ID for %pFX",
p);
"%s: Can't get Link State ID for %pFX",
__func__, p);
/* id.s_addr = 0; */
id.s_addr = 0xffffffff;
return id;
}
/* Masklen differs, then apply wildcard mask to Link State ID.
*/
else {
id->s_addr = 0xffffffff;
return LSID_NOT_AVAILABLE;
} else if (ip_masklen(al->mask) < p->prefixlen) {
/* Ref rfc2328,Appendex E.2
* the current prefix masklen is greater than the
* existing LSA, then generate the Link state ID,
* by setting all host bits in prefix addressa and
* originate.
*
* Eg: 1st Route : 10.0.0.0/16 - LSID:10.0.0.0
* 2nd Route : 10.0.0.0/24 - LSID:10.0.0.255
*/
masklen2ip(p->prefixlen, &mask);
id.s_addr = p->prefix.s_addr | (~mask.s_addr);
lsa = ospf_lsdb_lookup_by_id(ospf->lsdb, type, id,
id->s_addr = p->prefix.s_addr | (~mask.s_addr);
lsa = ospf_lsdb_lookup_by_id(ospf->lsdb, type, *id,
ospf->router_id);
if (lsa) {
if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
zlog_debug(
"ospf_lsa_unique_id(): Can't get Link State ID for %pFX",
p);
/* id.s_addr = 0; */
id.s_addr = 0xffffffff;
return id;
"%s: Can't get Link State ID for %pFX",
__func__, p);
id->s_addr = 0xffffffff;
return LSID_NOT_AVAILABLE;
}
} else {
/* Ref rfc2328,Appendex E.3
* the current prefix masklen is lesser than the
* existing LSA,then the originated LSA has to be
* refreshed by modifying masklen, cost and tag.
* Originate the old route info with new LSID by
* setting the host bits in prefix address.
*
* Eg: 1st Route : 10.0.0.0/24 - LSID:10.0.0.0
* 2nd Route : 10.0.0.0/16 - ?
* Since 2nd route mask len is less than firstone
* LSID has to be changed.
* 1st route LSID:10.0.0.255
* 2nd route LSID:10.0.0.0
*/
id->s_addr = lsa->data->id.s_addr | (~al->mask.s_addr);
lsa = ospf_lsdb_lookup_by_id(ospf->lsdb, type, *id,
ospf->router_id);
if (lsa && (ip_masklen(al->mask) != IPV4_MAX_BITLEN)) {
if (IS_DEBUG_OSPF(lsa, LSA_GENERATE))
zlog_debug(
"%s: Can't get Link State ID for %pFX",
__func__, p);
id->s_addr = 0xffffffff;
return LSID_NOT_AVAILABLE;
}
return LSID_CHANGE;
}
}
return id;
return LSID_AVAILABLE;
}

8
ospfd/ospf_lsa.h
View File

@ -208,6 +208,8 @@ struct as_external_lsa {
} e[1];
};
enum lsid_status { LSID_AVAILABLE = 0, LSID_CHANGE, LSID_NOT_AVAILABLE };
#include "ospfd/ospf_opaque.h"
/* Macros. */
@ -317,8 +319,10 @@ extern struct ospf_lsa *ospf_external_lsa_refresh(struct ospf *,
struct ospf_lsa *,
struct external_info *, int,
bool aggr);
extern struct in_addr ospf_lsa_unique_id(struct ospf *, struct ospf_lsdb *,
uint8_t, struct prefix_ipv4 *);
extern enum lsid_status ospf_lsa_unique_id(struct ospf *ospf,
struct ospf_lsdb *lsdb,
uint8_t type, struct prefix_ipv4 *p,
struct in_addr *addr);
extern void ospf_schedule_lsa_flood_area(struct ospf_area *, struct ospf_lsa *);
extern void ospf_schedule_lsa_flush_area(struct ospf_area *, struct ospf_lsa *);