proxmox-mirrors/mirror_frr
1
0
Fork 0
mirror of https://git.proxmox.com/git/mirror_frr synced 2025-11-04 10:07:04 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity
cc09ba4584
mirror_frr/ospfd/ospf_spf.c
Donald Sharp eb7e14011f ospfd: Fix ospf_ti_lfa drop of an entire table 
The new_rtrs variable was just generated and then dropped.  Let's
fix that entirely

Signed-off-by: Donald Sharp <sharpd@nvidia.com>
2023-03-17 10:37:40 -04:00

2074 lines
56 KiB
C
Raw Blame History

// SPDX-License-Identifier: GPL-2.0-or-later
/* OSPF SPF calculation.
* Copyright (C) 1999, 2000 Kunihiro Ishiguro, Toshiaki Takada
*/
#include <zebra.h>
#include "monotime.h"
#include "thread.h"
#include "memory.h"
#include "hash.h"
#include "linklist.h"
#include "prefix.h"
#include "if.h"
#include "table.h"
#include "log.h"
#include "sockunion.h" /* for inet_ntop () */
#include "ospfd/ospfd.h"
#include "ospfd/ospf_interface.h"
#include "ospfd/ospf_ism.h"
#include "ospfd/ospf_asbr.h"
#include "ospfd/ospf_lsa.h"
#include "ospfd/ospf_lsdb.h"
#include "ospfd/ospf_neighbor.h"
#include "ospfd/ospf_nsm.h"
#include "ospfd/ospf_spf.h"
#include "ospfd/ospf_route.h"
#include "ospfd/ospf_ia.h"
#include "ospfd/ospf_ase.h"
#include "ospfd/ospf_abr.h"
#include "ospfd/ospf_dump.h"
#include "ospfd/ospf_sr.h"
#include "ospfd/ospf_ti_lfa.h"
#include "ospfd/ospf_errors.h"
#ifdef SUPPORT_OSPF_API
#include "ospfd/ospf_apiserver.h"
#endif
/* Variables to ensure a SPF scheduled log message is printed only once */
static unsigned int spf_reason_flags = 0;
/* dummy vertex to flag "in spftree" */
static const struct vertex vertex_in_spftree = {};
#define LSA_SPF_IN_SPFTREE (struct vertex *)&vertex_in_spftree
#define LSA_SPF_NOT_EXPLORED NULL
static void ospf_clear_spf_reason_flags(void)
{
spf_reason_flags = 0;
}
static void ospf_spf_set_reason(ospf_spf_reason_t reason)
{
spf_reason_flags |= 1 << reason;
}
static void ospf_vertex_free(void *);
/*
* Heap related functions, for the managment of the candidates, to
* be used with pqueue.
*/
static int vertex_cmp(const struct vertex *v1, const struct vertex *v2)
{
if (v1->distance != v2->distance)
return v1->distance - v2->distance;
if (v1->type != v2->type) {
switch (v1->type) {
case OSPF_VERTEX_NETWORK:
return -1;
case OSPF_VERTEX_ROUTER:
return 1;
}
}
return 0;
}
DECLARE_SKIPLIST_NONUNIQ(vertex_pqueue, struct vertex, pqi, vertex_cmp);
static void lsdb_clean_stat(struct ospf_lsdb *lsdb)
{
struct route_table *table;
struct route_node *rn;
struct ospf_lsa *lsa;
int i;
for (i = OSPF_MIN_LSA; i < OSPF_MAX_LSA; i++) {
table = lsdb->type[i].db;
for (rn = route_top(table); rn; rn = route_next(rn))
if ((lsa = (rn->info)) != NULL)
lsa->stat = LSA_SPF_NOT_EXPLORED;
}
}
static struct vertex_nexthop *vertex_nexthop_new(void)
{
return XCALLOC(MTYPE_OSPF_NEXTHOP, sizeof(struct vertex_nexthop));
}
static void vertex_nexthop_free(struct vertex_nexthop *nh)
{
XFREE(MTYPE_OSPF_NEXTHOP, nh);
}
/*
* Free the canonical nexthop objects for an area, ie the nexthop objects
* attached to the first-hop router vertices, and any intervening network
* vertices.
*/
static void ospf_canonical_nexthops_free(struct vertex *root)
{
struct listnode *node, *nnode;
struct vertex *child;
for (ALL_LIST_ELEMENTS(root->children, node, nnode, child)) {
struct listnode *n2, *nn2;
struct vertex_parent *vp;
/*
* router vertices through an attached network each
* have a distinct (canonical / not inherited) nexthop
* which must be freed.
*
* A network vertex can only have router vertices as its
* children, so only one level of recursion is possible.
*/
if (child->type == OSPF_VERTEX_NETWORK)
ospf_canonical_nexthops_free(child);
/* Free child nexthops pointing back to this root vertex */
for (ALL_LIST_ELEMENTS(child->parents, n2, nn2, vp)) {
if (vp->parent == root && vp->nexthop) {
vertex_nexthop_free(vp->nexthop);
vp->nexthop = NULL;
if (vp->local_nexthop) {
vertex_nexthop_free(vp->local_nexthop);
vp->local_nexthop = NULL;
}
}
}
}
}
/*
* TODO: Parent list should be excised, in favour of maintaining only
* vertex_nexthop, with refcounts.
*/
static struct vertex_parent *vertex_parent_new(struct vertex *v, int backlink,
struct vertex_nexthop *hop,
struct vertex_nexthop *lhop)
{
struct vertex_parent *new;
new = XMALLOC(MTYPE_OSPF_VERTEX_PARENT, sizeof(struct vertex_parent));
new->parent = v;
new->backlink = backlink;
new->nexthop = hop;
new->local_nexthop = lhop;
return new;
}
static void vertex_parent_free(struct vertex_parent *p)
{
vertex_nexthop_free(p->local_nexthop);
vertex_nexthop_free(p->nexthop);
XFREE(MTYPE_OSPF_VERTEX_PARENT, p);
}
int vertex_parent_cmp(void *aa, void *bb)
{
struct vertex_parent *a = aa, *b = bb;
return IPV4_ADDR_CMP(&a->nexthop->router, &b->nexthop->router);
}
static struct vertex *ospf_vertex_new(struct ospf_area *area,
struct ospf_lsa *lsa)
{
struct vertex *new;
new = XCALLOC(MTYPE_OSPF_VERTEX, sizeof(struct vertex));
new->flags = 0;
new->type = lsa->data->type;
new->id = lsa->data->id;
new->lsa = lsa->data;
new->children = list_new();
new->parents = list_new();
new->parents->del = (void (*)(void *))vertex_parent_free;
new->parents->cmp = vertex_parent_cmp;
new->lsa_p = lsa;
lsa->stat = new;
listnode_add(area->spf_vertex_list, new);
if (IS_DEBUG_OSPF_EVENT)
zlog_debug("%s: Created %s vertex %pI4", __func__,
new->type == OSPF_VERTEX_ROUTER ? "Router"
: "Network",
&new->lsa->id);
return new;
}
static void ospf_vertex_free(void *data)
{
struct vertex *v = data;
if (IS_DEBUG_OSPF_EVENT)
zlog_debug("%s: Free %s vertex %pI4", __func__,
v->type == OSPF_VERTEX_ROUTER ? "Router" : "Network",
&v->lsa->id);
if (v->children)
list_delete(&v->children);
if (v->parents)
list_delete(&v->parents);
v->lsa = NULL;
XFREE(MTYPE_OSPF_VERTEX, v);
}
static void ospf_vertex_dump(const char *msg, struct vertex *v,
int print_parents, int print_children)
{
if (!IS_DEBUG_OSPF_EVENT)
return;
zlog_debug("%s %s vertex %pI4 distance %u flags %u", msg,
v->type == OSPF_VERTEX_ROUTER ? "Router" : "Network",
&v->lsa->id, v->distance, (unsigned int)v->flags);
if (print_parents) {
struct listnode *node;
struct vertex_parent *vp;
for (ALL_LIST_ELEMENTS_RO(v->parents, node, vp)) {
if (vp) {
zlog_debug(
"parent %pI4 backlink %d nexthop %pI4 lsa pos %d",
&vp->parent->lsa->id, vp->backlink,
&vp->nexthop->router,
vp->nexthop->lsa_pos);
}
}
}
if (print_children) {
struct listnode *cnode;
struct vertex *cv;
for (ALL_LIST_ELEMENTS_RO(v->children, cnode, cv))
ospf_vertex_dump(" child:", cv, 0, 0);
}
}
/* Add a vertex to the list of children in each of its parents. */
static void ospf_vertex_add_parent(struct vertex *v)
{
struct vertex_parent *vp;
struct listnode *node;
assert(v && v->parents);
for (ALL_LIST_ELEMENTS_RO(v->parents, node, vp)) {
assert(vp->parent && vp->parent->children);
/* No need to add two links from the same parent. */
if (listnode_lookup(vp->parent->children, v) == NULL)
listnode_add(vp->parent->children, v);
}
}
/* Find a vertex according to its router id */
struct vertex *ospf_spf_vertex_find(struct in_addr id, struct list *vertex_list)
{
struct listnode *node;
struct vertex *found;
for (ALL_LIST_ELEMENTS_RO(vertex_list, node, found)) {
if (found->id.s_addr == id.s_addr)
return found;
}
return NULL;
}
/* Find a vertex parent according to its router id */
struct vertex_parent *ospf_spf_vertex_parent_find(struct in_addr id,
struct vertex *vertex)
{
struct listnode *node;
struct vertex_parent *found;
for (ALL_LIST_ELEMENTS_RO(vertex->parents, node, found)) {
if (found->parent->id.s_addr == id.s_addr)
return found;
}
return NULL;
}
struct vertex *ospf_spf_vertex_by_nexthop(struct vertex *root,
struct in_addr *nexthop)
{
struct listnode *node;
struct vertex *child;
struct vertex_parent *vertex_parent;
for (ALL_LIST_ELEMENTS_RO(root->children, node, child)) {
vertex_parent = ospf_spf_vertex_parent_find(root->id, child);
if (vertex_parent->nexthop->router.s_addr == nexthop->s_addr)
return child;
}
return NULL;
}
/* Create a deep copy of a SPF vertex without children and parents */
static struct vertex *ospf_spf_vertex_copy(struct vertex *vertex)
{
struct vertex *copy;
copy = XCALLOC(MTYPE_OSPF_VERTEX, sizeof(struct vertex));
memcpy(copy, vertex, sizeof(struct vertex));
copy->parents = list_new();
copy->parents->del = (void (*)(void *))vertex_parent_free;
copy->parents->cmp = vertex_parent_cmp;
copy->children = list_new();
return copy;
}
/* Create a deep copy of a SPF vertex_parent */
static struct vertex_parent *
ospf_spf_vertex_parent_copy(struct vertex_parent *vertex_parent)
{
struct vertex_parent *vertex_parent_copy;
struct vertex_nexthop *nexthop_copy, *local_nexthop_copy;
vertex_parent_copy =
XCALLOC(MTYPE_OSPF_VERTEX, sizeof(struct vertex_parent));
nexthop_copy = vertex_nexthop_new();
local_nexthop_copy = vertex_nexthop_new();
memcpy(vertex_parent_copy, vertex_parent, sizeof(struct vertex_parent));
memcpy(nexthop_copy, vertex_parent->nexthop,
sizeof(struct vertex_nexthop));
memcpy(local_nexthop_copy, vertex_parent->local_nexthop,
sizeof(struct vertex_nexthop));
vertex_parent_copy->nexthop = nexthop_copy;
vertex_parent_copy->local_nexthop = local_nexthop_copy;
return vertex_parent_copy;
}
/* Create a deep copy of a SPF tree */
void ospf_spf_copy(struct vertex *vertex, struct list *vertex_list)
{
struct listnode *node;
struct vertex *vertex_copy, *child, *child_copy, *parent_copy;
struct vertex_parent *vertex_parent, *vertex_parent_copy;
/* First check if the node is already in the vertex list */
vertex_copy = ospf_spf_vertex_find(vertex->id, vertex_list);
if (!vertex_copy) {
vertex_copy = ospf_spf_vertex_copy(vertex);
listnode_add(vertex_list, vertex_copy);
}
/* Copy all parents, create parent nodes if necessary */
for (ALL_LIST_ELEMENTS_RO(vertex->parents, node, vertex_parent)) {
parent_copy = ospf_spf_vertex_find(vertex_parent->parent->id,
vertex_list);
if (!parent_copy) {
parent_copy =
ospf_spf_vertex_copy(vertex_parent->parent);
listnode_add(vertex_list, parent_copy);
}
vertex_parent_copy = ospf_spf_vertex_parent_copy(vertex_parent);
vertex_parent_copy->parent = parent_copy;
listnode_add(vertex_copy->parents, vertex_parent_copy);
}
/* Copy all children, create child nodes if necessary */
for (ALL_LIST_ELEMENTS_RO(vertex->children, node, child)) {
child_copy = ospf_spf_vertex_find(child->id, vertex_list);
if (!child_copy) {
child_copy = ospf_spf_vertex_copy(child);
listnode_add(vertex_list, child_copy);
}
listnode_add(vertex_copy->children, child_copy);
}
/* Finally continue copying with child nodes */
for (ALL_LIST_ELEMENTS_RO(vertex->children, node, child))
ospf_spf_copy(child, vertex_list);
}
static void ospf_spf_remove_branch(struct vertex_parent *vertex_parent,
struct vertex *child,
struct list *vertex_list)
{
struct listnode *node, *nnode, *inner_node, *inner_nnode;
struct vertex *grandchild;
struct vertex_parent *vertex_parent_found;
bool has_more_links = false;
/*
* First check if there are more nexthops for that parent to that child
*/
for (ALL_LIST_ELEMENTS_RO(child->parents, node, vertex_parent_found)) {
if (vertex_parent_found->parent->id.s_addr
== vertex_parent->parent->id.s_addr
&& vertex_parent_found->nexthop->router.s_addr
!= vertex_parent->nexthop->router.s_addr)
has_more_links = true;
}
/*
* No more links from that parent? Then delete the child from its
* children list.
*/
if (!has_more_links)
listnode_delete(vertex_parent->parent->children, child);
/*
* Delete the vertex_parent from the child parents list, this needs to
* be done anyway.
*/
listnode_delete(child->parents, vertex_parent);
/*
* Are there actually more parents left? If not, then delete the child!
* This is done by recursively removing the links to the grandchildren,
* such that finally the child can be removed without leaving unused
* partial branches.
*/
if (child->parents->count == 0) {
for (ALL_LIST_ELEMENTS(child->children, node, nnode,
grandchild)) {
for (ALL_LIST_ELEMENTS(grandchild->parents, inner_node,
inner_nnode,
vertex_parent_found)) {
ospf_spf_remove_branch(vertex_parent_found,
grandchild, vertex_list);
}
}
listnode_delete(vertex_list, child);
ospf_vertex_free(child);
}
}
static int ospf_spf_remove_link(struct vertex *vertex, struct list *vertex_list,
struct router_lsa_link *link)
{
struct listnode *node, *inner_node;
struct vertex *child;
struct vertex_parent *vertex_parent;
/*
* Identify the node who shares a subnet (given by the link) with a
* child and remove the branch of this particular child.
*/
for (ALL_LIST_ELEMENTS_RO(vertex->children, node, child)) {
for (ALL_LIST_ELEMENTS_RO(child->parents, inner_node,
vertex_parent)) {
if ((vertex_parent->local_nexthop->router.s_addr
& link->link_data.s_addr)
== (link->link_id.s_addr
& link->link_data.s_addr)) {
ospf_spf_remove_branch(vertex_parent, child,
vertex_list);
return 0;
}
}
}
/* No link found yet, move on recursively */
for (ALL_LIST_ELEMENTS_RO(vertex->children, node, child)) {
if (ospf_spf_remove_link(child, vertex_list, link) == 0)
return 0;
}
/* link was not removed yet */
return 1;
}
void ospf_spf_remove_resource(struct vertex *vertex, struct list *vertex_list,
struct protected_resource *resource)
{
struct listnode *node, *nnode;
struct vertex *found;
struct vertex_parent *vertex_parent;
switch (resource->type) {
case OSPF_TI_LFA_LINK_PROTECTION:
ospf_spf_remove_link(vertex, vertex_list, resource->link);
break;
case OSPF_TI_LFA_NODE_PROTECTION:
found = ospf_spf_vertex_find(resource->router_id, vertex_list);
if (!found)
break;
/*
* Remove the node by removing all links from its parents. Note
* that the child is automatically removed here with the last
* link from a parent, hence no explicit removal of the node.
*/
for (ALL_LIST_ELEMENTS(found->parents, node, nnode,
vertex_parent))
ospf_spf_remove_branch(vertex_parent, found,
vertex_list);
break;
case OSPF_TI_LFA_UNDEFINED_PROTECTION:
/* do nothing */
break;
}
}
static void ospf_spf_init(struct ospf_area *area, struct ospf_lsa *root_lsa,
bool is_dry_run, bool is_root_node)
{
struct list *vertex_list;
struct vertex *v;
/* Create vertex list */
vertex_list = list_new();
vertex_list->del = ospf_vertex_free;
area->spf_vertex_list = vertex_list;
/* Create root node. */
v = ospf_vertex_new(area, root_lsa);
area->spf = v;
area->spf_dry_run = is_dry_run;
area->spf_root_node = is_root_node;
/* Reset ABR and ASBR router counts. */
area->abr_count = 0;
area->asbr_count = 0;
}
/* return index of link back to V from W, or -1 if no link found */
static int ospf_lsa_has_link(struct lsa_header *w, struct lsa_header *v)
{
unsigned int i, length;
struct router_lsa *rl;
struct network_lsa *nl;
/* In case of W is Network LSA. */
if (w->type == OSPF_NETWORK_LSA) {
if (v->type == OSPF_NETWORK_LSA)
return -1;
nl = (struct network_lsa *)w;
length = (ntohs(w->length) - OSPF_LSA_HEADER_SIZE - 4) / 4;
for (i = 0; i < length; i++)
if (IPV4_ADDR_SAME(&nl->routers[i], &v->id))
return i;
return -1;
}
/* In case of W is Router LSA. */
if (w->type == OSPF_ROUTER_LSA) {
rl = (struct router_lsa *)w;
length = ntohs(w->length);
for (i = 0; i < ntohs(rl->links)
&& length >= sizeof(struct router_lsa);
i++, length -= 12) {
switch (rl->link[i].type) {
case LSA_LINK_TYPE_POINTOPOINT:
case LSA_LINK_TYPE_VIRTUALLINK:
/* Router LSA ID. */
if (v->type == OSPF_ROUTER_LSA
&& IPV4_ADDR_SAME(&rl->link[i].link_id,
&v->id)) {
return i;
}
break;
case LSA_LINK_TYPE_TRANSIT:
/* Network LSA ID. */
if (v->type == OSPF_NETWORK_LSA
&& IPV4_ADDR_SAME(&rl->link[i].link_id,
&v->id)) {
return i;
}
break;
case LSA_LINK_TYPE_STUB:
/* Stub can't lead anywhere, carry on */
continue;
default:
break;
}
}
}
return -1;
}
/*
* Find the next link after prev_link from v to w. If prev_link is
* NULL, return the first link from v to w. Ignore stub and virtual links;
* these link types will never be returned.
*/
static struct router_lsa_link *
ospf_get_next_link(struct vertex *v, struct vertex *w,
struct router_lsa_link *prev_link)
{
uint8_t *p;
uint8_t *lim;
uint8_t lsa_type = LSA_LINK_TYPE_TRANSIT;
struct router_lsa_link *l;
if (w->type == OSPF_VERTEX_ROUTER)
lsa_type = LSA_LINK_TYPE_POINTOPOINT;
if (prev_link == NULL)
p = ((uint8_t *)v->lsa) + OSPF_LSA_HEADER_SIZE + 4;
else {
p = (uint8_t *)prev_link;
p += (OSPF_ROUTER_LSA_LINK_SIZE
+ (prev_link->m[0].tos_count * OSPF_ROUTER_LSA_TOS_SIZE));
}
lim = ((uint8_t *)v->lsa) + ntohs(v->lsa->length);
while (p < lim) {
l = (struct router_lsa_link *)p;
p += (OSPF_ROUTER_LSA_LINK_SIZE
+ (l->m[0].tos_count * OSPF_ROUTER_LSA_TOS_SIZE));
if (l->m[0].type != lsa_type)
continue;
if (IPV4_ADDR_SAME(&l->link_id, &w->id))
return l;
}
return NULL;
}
static void ospf_spf_flush_parents(struct vertex *w)
{
struct vertex_parent *vp;
struct listnode *ln, *nn;
/* delete the existing nexthops */
for (ALL_LIST_ELEMENTS(w->parents, ln, nn, vp)) {
list_delete_node(w->parents, ln);
vertex_parent_free(vp);
}
}
/*
* Consider supplied next-hop for inclusion to the supplied list of
* equal-cost next-hops, adjust list as necessary.
*
* Returns vertex parent pointer if created otherwise `NULL` if it already
* exists.
*/
static struct vertex_parent *ospf_spf_add_parent(struct vertex *v,
struct vertex *w,
struct vertex_nexthop *newhop,
struct vertex_nexthop *newlhop,
unsigned int distance)
{
struct vertex_parent *vp, *wp;
struct listnode *node;
/* we must have a newhop, and a distance */
assert(v && w && newhop);
assert(distance);
/*
* IFF w has already been assigned a distance, then we shouldn't get
* here unless callers have determined V(l)->W is shortest /
* equal-shortest path (0 is a special case distance (no distance yet
* assigned)).
*/
if (w->distance)
assert(distance <= w->distance);
else
w->distance = distance;
if (IS_DEBUG_OSPF_EVENT)
zlog_debug("%s: Adding %pI4 as parent of %pI4", __func__,
&v->lsa->id, &w->lsa->id);
/*
* Adding parent for a new, better path: flush existing parents from W.
*/
if (distance < w->distance) {
if (IS_DEBUG_OSPF_EVENT)
zlog_debug(
"%s: distance %d better than %d, flushing existing parents",
__func__, distance, w->distance);
ospf_spf_flush_parents(w);
w->distance = distance;
}
/*
* new parent is <= existing parents, add it to parent list (if nexthop
* not on parent list)
*/
for (ALL_LIST_ELEMENTS_RO(w->parents, node, wp)) {
if (memcmp(newhop, wp->nexthop, sizeof(*newhop)) == 0) {
if (IS_DEBUG_OSPF_EVENT)
zlog_debug(
"%s: ... nexthop already on parent list, skipping add",
__func__);
return NULL;
}
}
vp = vertex_parent_new(v, ospf_lsa_has_link(w->lsa, v->lsa), newhop,
newlhop);
listnode_add_sort(w->parents, vp);
return vp;
}
static int match_stub_prefix(struct lsa_header *lsa, struct in_addr v_link_addr,
struct in_addr w_link_addr)
{
uint8_t *p, *lim;
struct router_lsa_link *l = NULL;
struct in_addr masked_lsa_addr;
if (lsa->type != OSPF_ROUTER_LSA)
return 0;
p = ((uint8_t *)lsa) + OSPF_LSA_HEADER_SIZE + 4;
lim = ((uint8_t *)lsa) + ntohs(lsa->length);
while (p < lim) {
l = (struct router_lsa_link *)p;
p += (OSPF_ROUTER_LSA_LINK_SIZE
+ (l->m[0].tos_count * OSPF_ROUTER_LSA_TOS_SIZE));
if (l->m[0].type != LSA_LINK_TYPE_STUB)
continue;
masked_lsa_addr.s_addr =
(l->link_id.s_addr & l->link_data.s_addr);
/* check that both links belong to the same stub subnet */
if ((masked_lsa_addr.s_addr
== (v_link_addr.s_addr & l->link_data.s_addr))
&& (masked_lsa_addr.s_addr
== (w_link_addr.s_addr & l->link_data.s_addr)))
return 1;
}
return 0;
}
/*
* 16.1.1. Calculate nexthop from root through V (parent) to
* vertex W (destination), with given distance from root->W.
*
* The link must be supplied if V is the root vertex. In all other cases
* it may be NULL.
*
* Note that this function may fail, hence the state of the destination
* vertex, W, should /not/ be modified in a dependent manner until
* this function returns. This function will update the W vertex with the
* provided distance as appropriate.
*/
static unsigned int ospf_nexthop_calculation(struct ospf_area *area,
struct vertex *v, struct vertex *w,
struct router_lsa_link *l,
unsigned int distance, int lsa_pos)
{
struct listnode *node, *nnode;
struct vertex_nexthop *nh, *lnh;
struct vertex_parent *vp;
unsigned int added = 0;
if (IS_DEBUG_OSPF_EVENT) {
zlog_debug("%s: Start", __func__);
ospf_vertex_dump("V (parent):", v, 1, 1);
ospf_vertex_dump("W (dest) :", w, 1, 1);
zlog_debug("V->W distance: %d", distance);
}
if (v == area->spf) {
/*
* 16.1.1 para 4. In the first case, the parent vertex (V) is
* the root (the calculating router itself). This means that
* the destination is either a directly connected network or
* directly connected router. The outgoing interface in this
* case is simply the OSPF interface connecting to the
* destination network/router.
*/
/* we *must* be supplied with the link data */
assert(l != NULL);
if (IS_DEBUG_OSPF_EVENT)
zlog_debug(
"%s: considering link type:%d link_id:%pI4 link_data:%pI4",
__func__, l->m[0].type, &l->link_id,
&l->link_data);
if (w->type == OSPF_VERTEX_ROUTER) {
/*
* l is a link from v to w l2 will be link from w to v
*/
struct router_lsa_link *l2 = NULL;
if (l->m[0].type == LSA_LINK_TYPE_POINTOPOINT) {
struct ospf_interface *oi = NULL;
struct in_addr nexthop = {.s_addr = 0};
if (area->spf_root_node) {
oi = ospf_if_lookup_by_lsa_pos(area,
lsa_pos);
if (!oi) {
zlog_debug(
"%s: OI not found in LSA: lsa_pos: %d link_id:%pI4 link_data:%pI4",
__func__, lsa_pos,
&l->link_id,
&l->link_data);
return 0;
}
}
/*
* If the destination is a router which connects
* to the calculating router via a
* Point-to-MultiPoint network, the
* destination's next hop IP address(es) can be
* determined by examining the destination's
* router-LSA: each link pointing back to the
* calculating router and having a Link Data
* field belonging to the Point-to-MultiPoint
* network provides an IP address of the next
* hop router.
*
* At this point l is a link from V to W, and V
* is the root ("us"). If it is a point-to-
* multipoint interface, then look through the
* links in the opposite direction (W to V).
* If any of them have an address that lands
* within the subnet declared by the PtMP link,
* then that link is a constituent of the PtMP
* link, and its address is a nexthop address
* for V.
*
* Note for point-to-point interfaces:
*
* Having nexthop = 0 (as proposed in the RFC)
* is tempting, but NOT acceptable. It breaks
* AS-External routes with a forwarding address,
* since ospf_ase_complete_direct_routes() will
* mistakenly assume we've reached the last hop
* and should place the forwarding address as
* nexthop. Also, users may configure multi-
* access links in p2p mode, so we need the IP
* to ARP the nexthop.
*
* If the calculating router is the SPF root
* node and the link is P2P then access the
* interface information directly. This can be
* crucial when e.g. IP unnumbered is used
* where 'correct' nexthop information are not
* available via Router LSAs.
*
* Otherwise handle P2P and P2MP the same way
* as described above using a reverse lookup to
* figure out the nexthop.
*/
/*
* HACK: we don't know (yet) how to distinguish
* between P2P and P2MP interfaces by just
* looking at LSAs, which is important for
* TI-LFA since you want to do SPF calculations
* from the perspective of other nodes. Since
* TI-LFA is currently not implemented for P2MP
* we just check here if it is enabled and then
* blindly assume that P2P is used. Ultimately
* the interface code needs to be removed
* somehow.
*/
if (area->ospf->ti_lfa_enabled
|| (oi && oi->type == OSPF_IFTYPE_POINTOPOINT)
|| (oi && oi->type == OSPF_IFTYPE_POINTOMULTIPOINT
&& oi->address->prefixlen == IPV4_MAX_BITLEN)) {
struct ospf_neighbor *nbr_w = NULL;
/* Calculating node is root node, link
* is P2P */
if (area->spf_root_node) {
nbr_w = ospf_nbr_lookup_by_routerid(
oi->nbrs, &l->link_id);
if (nbr_w) {
added = 1;
nexthop = nbr_w->src;
}
}
/* Reverse lookup */
if (!added) {
while ((l2 = ospf_get_next_link(
w, v, l2))) {
if (match_stub_prefix(
v->lsa,
l->link_data,
l2->link_data)) {
added = 1;
nexthop =
l2->link_data;
break;
}
}
}
} else if (oi && oi->type
== OSPF_IFTYPE_POINTOMULTIPOINT) {
struct prefix_ipv4 la;
la.family = AF_INET;
la.prefixlen = oi->address->prefixlen;
/*
* V links to W on PtMP interface;
* find the interface address on W
*/
while ((l2 = ospf_get_next_link(w, v,
l2))) {
la.prefix = l2->link_data;
if (prefix_cmp((struct prefix
*)&la,
oi->address)
!= 0)
continue;
added = 1;
nexthop = l2->link_data;
break;
}
}
if (added) {
nh = vertex_nexthop_new();
nh->router = nexthop;
nh->lsa_pos = lsa_pos;
/*
* Since v is the root the nexthop and
* local nexthop are the same.
*/
lnh = vertex_nexthop_new();
memcpy(lnh, nh,
sizeof(struct vertex_nexthop));
if (ospf_spf_add_parent(v, w, nh, lnh,
distance) ==
NULL) {
vertex_nexthop_free(nh);
vertex_nexthop_free(lnh);
}
return 1;
} else
zlog_info(
"%s: could not determine nexthop for link %s",
__func__, oi ? oi->ifp->name : "");
} /* end point-to-point link from V to W */
else if (l->m[0].type == LSA_LINK_TYPE_VIRTUALLINK) {
/*
* VLink implementation limitations:
* a) vl_data can only reference one nexthop,
* so no ECMP to backbone through VLinks.
* Though transit-area summaries may be
* considered, and those can be ECMP.
* b) We can only use /one/ VLink, even if
* multiple ones exist this router through
* multiple transit-areas.
*/
struct ospf_vl_data *vl_data;
vl_data = ospf_vl_lookup(area->ospf, NULL,
l->link_id);
if (vl_data
&& CHECK_FLAG(vl_data->flags,
OSPF_VL_FLAG_APPROVED)) {
nh = vertex_nexthop_new();
nh->router = vl_data->nexthop.router;
nh->lsa_pos = vl_data->nexthop.lsa_pos;
/*
* Since v is the root the nexthop and
* local nexthop are the same.
*/
lnh = vertex_nexthop_new();
memcpy(lnh, nh,
sizeof(struct vertex_nexthop));
if (ospf_spf_add_parent(v, w, nh, lnh,
distance) ==
NULL) {
vertex_nexthop_free(nh);
vertex_nexthop_free(lnh);
}
return 1;
} else
zlog_info(
"%s: vl_data for VL link not found",
__func__);
} /* end virtual-link from V to W */
return 0;
} /* end W is a Router vertex */
else {
assert(w->type == OSPF_VERTEX_NETWORK);
nh = vertex_nexthop_new();
nh->router.s_addr = 0; /* Nexthop not required */
nh->lsa_pos = lsa_pos;
/*
* Since v is the root the nexthop and
* local nexthop are the same.
*/
lnh = vertex_nexthop_new();
memcpy(lnh, nh, sizeof(struct vertex_nexthop));
if (ospf_spf_add_parent(v, w, nh, lnh, distance) ==
NULL) {
vertex_nexthop_free(nh);
vertex_nexthop_free(lnh);
}
return 1;
}
} /* end V is the root */
/* Check if W's parent is a network connected to root. */
else if (v->type == OSPF_VERTEX_NETWORK) {
/* See if any of V's parents are the root. */
for (ALL_LIST_ELEMENTS(v->parents, node, nnode, vp)) {
if (vp->parent == area->spf) {
/*
* 16.1.1 para 5. ...the parent vertex is a
* network that directly connects the
* calculating router to the destination
* router. The list of next hops is then
* determined by examining the destination's
* router-LSA ...
*/
assert(w->type == OSPF_VERTEX_ROUTER);
while ((l = ospf_get_next_link(w, v, l))) {
/*
* ... For each link in the router-LSA
* that points back to the parent
* network, the link's Link Data field
* provides the IP address of a next hop
* router. The outgoing interface to use
* can then be derived from the next
* hop IP address (or it can be
* inherited from the parent network).
*/
nh = vertex_nexthop_new();
nh->router = l->link_data;
nh->lsa_pos = vp->nexthop->lsa_pos;
/*
* Since v is the root the nexthop and
* local nexthop are the same.
*/
lnh = vertex_nexthop_new();
memcpy(lnh, nh,
sizeof(struct vertex_nexthop));
added = 1;
if (ospf_spf_add_parent(v, w, nh, lnh,
distance) ==
NULL) {
vertex_nexthop_free(nh);
vertex_nexthop_free(lnh);
}
}
/*
* Note lack of return is deliberate. See next
* comment.
*/
}
}
/*
* NB: This code is non-trivial.
*
* E.g. it is not enough to know that V connects to the root. It
* is also important that the while above, looping through all
* links from W->V found at least one link, so that we know
* there is bi-directional connectivity between V and W (which
* need not be the case, e.g. when OSPF has not yet converged
* fully). Otherwise, if we /always/ return here, without having
* checked that root->V->-W actually resulted in a valid nexthop
* being created, then we we will prevent SPF from finding/using
* higher cost paths.
*
* It is important, if root->V->W has not been added, that we
* continue through to the intervening-router nexthop code
* below. So as to ensure other paths to V may be used. This
* avoids unnecessary blackholes while OSPF is converging.
*
* I.e. we may have arrived at this function, examining V -> W,
* via workable paths other than root -> V, and it's important
* to avoid getting "confused" by non-working root->V->W path
* - it's important to *not* lose the working non-root paths,
* just because of a non-viable root->V->W.
*/
if (added)
return added;
}
/*
* 16.1.1 para 4. If there is at least one intervening router in the
* current shortest path between the destination and the root, the
* destination simply inherits the set of next hops from the
* parent.
*/
if (IS_DEBUG_OSPF_EVENT)
zlog_debug("%s: Intervening routers, adding parent(s)",
__func__);
for (ALL_LIST_ELEMENTS(v->parents, node, nnode, vp)) {
added = 1;
/*
* The nexthop is inherited, but the local nexthop still needs
* to be created.
*/
if (l) {
lnh = vertex_nexthop_new();
lnh->router = l->link_data;
lnh->lsa_pos = lsa_pos;
} else {
lnh = NULL;
}
nh = vertex_nexthop_new();
*nh = *vp->nexthop;
if (ospf_spf_add_parent(v, w, nh, lnh, distance) == NULL) {
vertex_nexthop_free(nh);
vertex_nexthop_free(lnh);
}
}
return added;
}
static int ospf_spf_is_protected_resource(struct ospf_area *area,
struct router_lsa_link *link,
struct lsa_header *lsa)
{
uint8_t *p, *lim;
struct router_lsa_link *p_link;
struct router_lsa_link *l = NULL;
struct in_addr router_id;
int link_type;
if (!area->spf_protected_resource)
return 0;
link_type = link->m[0].type;
switch (area->spf_protected_resource->type) {
case OSPF_TI_LFA_LINK_PROTECTION:
p_link = area->spf_protected_resource->link;
if (!p_link)
return 0;
/* For P2P: check if the link belongs to the same subnet */
if (link_type == LSA_LINK_TYPE_POINTOPOINT
&& (p_link->link_id.s_addr & p_link->link_data.s_addr)
== (link->link_data.s_addr
& p_link->link_data.s_addr))
return 1;
/* For stub: check if this the same subnet */
if (link_type == LSA_LINK_TYPE_STUB
&& (p_link->link_id.s_addr == link->link_id.s_addr)
&& (p_link->link_data.s_addr == link->link_data.s_addr))
return 1;
break;
case OSPF_TI_LFA_NODE_PROTECTION:
router_id = area->spf_protected_resource->router_id;
if (router_id.s_addr == INADDR_ANY)
return 0;
/* For P2P: check if the link leads to the protected node */
if (link_type == LSA_LINK_TYPE_POINTOPOINT
&& link->link_id.s_addr == router_id.s_addr)
return 1;
/* The rest is about stub links! */
if (link_type != LSA_LINK_TYPE_STUB)
return 0;
/*
* Check if there's a P2P link in the router LSA with the
* corresponding link data in the same subnet.
*/
p = ((uint8_t *)lsa) + OSPF_LSA_HEADER_SIZE + 4;
lim = ((uint8_t *)lsa) + ntohs(lsa->length);
while (p < lim) {
l = (struct router_lsa_link *)p;
p += (OSPF_ROUTER_LSA_LINK_SIZE
+ (l->m[0].tos_count * OSPF_ROUTER_LSA_TOS_SIZE));
/* We only care about P2P with the proper link id */
if ((l->m[0].type != LSA_LINK_TYPE_POINTOPOINT)
|| (l->link_id.s_addr != router_id.s_addr))
continue;
/* Link data in the subnet given by the link? */
if ((link->link_id.s_addr & link->link_data.s_addr)
== (l->link_data.s_addr & link->link_data.s_addr))
return 1;
}
break;
case OSPF_TI_LFA_UNDEFINED_PROTECTION:
break;
}
return 0;
}
/*
* For TI-LFA we need the reverse SPF for Q spaces. The reverse SPF is created
* by honoring the weight of the reverse 'edge', e.g. the edge from W to V, and
* NOT the weight of the 'edge' from V to W as usual. Hence we need to find the
* corresponding link in the LSA of W and extract the particular weight.
*
* TODO: Only P2P supported by now!
*/
static uint16_t get_reverse_distance(struct vertex *v,
struct router_lsa_link *l,
struct ospf_lsa *w_lsa)
{
uint8_t *p, *lim;
struct router_lsa_link *w_link;
uint16_t distance = 0;
assert(w_lsa && w_lsa->data);
p = ((uint8_t *)w_lsa->data) + OSPF_LSA_HEADER_SIZE + 4;
lim = ((uint8_t *)w_lsa->data) + ntohs(w_lsa->data->length);
while (p < lim) {
w_link = (struct router_lsa_link *)p;
p += (OSPF_ROUTER_LSA_LINK_SIZE
+ (w_link->m[0].tos_count * OSPF_ROUTER_LSA_TOS_SIZE));
/* Only care about P2P with link ID equal to V's router id */
if (w_link->m[0].type == LSA_LINK_TYPE_POINTOPOINT
&& w_link->link_id.s_addr == v->id.s_addr) {
distance = ntohs(w_link->m[0].metric);
break;
}
}
/*
* This might happen if the LSA for W is not complete yet. In this
* case we take the weight of the 'forward' link from V. When the LSA
* for W is completed the reverse SPF is run again anyway.
*/
if (distance == 0)
distance = ntohs(l->m[0].metric);
if (IS_DEBUG_OSPF_EVENT)
zlog_debug("%s: reversed distance is %u", __func__, distance);
return distance;
}
/*
* RFC2328 16.1 (2).
* v is on the SPF tree. Examine the links in v's LSA. Update the list of
* candidates with any vertices not already on the list. If a lower-cost path
* is found to a vertex already on the candidate list, store the new cost.
*/
static void ospf_spf_next(struct vertex *v, struct ospf_area *area,
struct vertex_pqueue_head *candidate)
{
struct ospf_lsa *w_lsa = NULL;
uint8_t *p;
uint8_t *lim;
struct router_lsa_link *l = NULL;
struct in_addr *r;
int type = 0, lsa_pos = -1, lsa_pos_next = 0;
uint16_t link_distance;
/*
* If this is a router-LSA, and bit V of the router-LSA (see Section
* A.4.2:RFC2328) is set, set Area A's TransitCapability to true.
*/
if (v->type == OSPF_VERTEX_ROUTER) {
if (IS_ROUTER_LSA_VIRTUAL((struct router_lsa *)v->lsa))
area->transit = OSPF_TRANSIT_TRUE;
}
if (IS_DEBUG_OSPF_EVENT)
zlog_debug("%s: Next vertex of %s vertex %pI4", __func__,
v->type == OSPF_VERTEX_ROUTER ? "Router" : "Network",
&v->lsa->id);
p = ((uint8_t *)v->lsa) + OSPF_LSA_HEADER_SIZE + 4;
lim = ((uint8_t *)v->lsa) + ntohs(v->lsa->length);
while (p < lim) {
struct vertex *w;
unsigned int distance;
/* In case of V is Router-LSA. */
if (v->lsa->type == OSPF_ROUTER_LSA) {
l = (struct router_lsa_link *)p;
lsa_pos = lsa_pos_next; /* LSA link position */
lsa_pos_next++;
p += (OSPF_ROUTER_LSA_LINK_SIZE
+ (l->m[0].tos_count * OSPF_ROUTER_LSA_TOS_SIZE));
/*
* (a) If this is a link to a stub network, examine the
* next link in V's LSA. Links to stub networks will
* be considered in the second stage of the shortest
* path calculation.
*/
if ((type = l->m[0].type) == LSA_LINK_TYPE_STUB)
continue;
/*
* Don't process TI-LFA protected resources.
*
* TODO: Replace this by a proper solution, e.g. remove
* corresponding links from the LSDB and run the SPF
* algo with the stripped-down LSDB.
*/
if (ospf_spf_is_protected_resource(area, l, v->lsa))
continue;
/*
* (b) Otherwise, W is a transit vertex (router or
* transit network). Look up the vertex W's LSA
* (router-LSA or network-LSA) in Area A's link state
* database.
*/
switch (type) {
case LSA_LINK_TYPE_POINTOPOINT:
case LSA_LINK_TYPE_VIRTUALLINK:
if (type == LSA_LINK_TYPE_VIRTUALLINK
&& IS_DEBUG_OSPF_EVENT)
zlog_debug(
"looking up LSA through VL: %pI4",
&l->link_id);
w_lsa = ospf_lsa_lookup(area->ospf, area,
OSPF_ROUTER_LSA,
l->link_id, l->link_id);
if (w_lsa && IS_DEBUG_OSPF_EVENT)
zlog_debug("found Router LSA %pI4",
&l->link_id);
break;
case LSA_LINK_TYPE_TRANSIT:
if (IS_DEBUG_OSPF_EVENT)
zlog_debug(
"Looking up Network LSA, ID: %pI4",
&l->link_id);
w_lsa = ospf_lsa_lookup_by_id(
area, OSPF_NETWORK_LSA, l->link_id);
if (w_lsa && IS_DEBUG_OSPF_EVENT)
zlog_debug("found the LSA");
break;
default:
flog_warn(EC_OSPF_LSA,
"Invalid LSA link type %d", type);
continue;
}
/*
* For TI-LFA we might need the reverse SPF.
* Currently only works with P2P!
*/
if (type == LSA_LINK_TYPE_POINTOPOINT
&& area->spf_reversed)
link_distance =
get_reverse_distance(v, l, w_lsa);
else
link_distance = ntohs(l->m[0].metric);
/* step (d) below */
distance = v->distance + link_distance;
} else {
/* In case of V is Network-LSA. */
r = (struct in_addr *)p;
p += sizeof(struct in_addr);
/* Lookup the vertex W's LSA. */
w_lsa = ospf_lsa_lookup_by_id(area, OSPF_ROUTER_LSA,
*r);
if (w_lsa && IS_DEBUG_OSPF_EVENT)
zlog_debug("found Router LSA %pI4",
&w_lsa->data->id);
/* step (d) below */
distance = v->distance;
}
/*
* (b cont.) If the LSA does not exist, or its LS age is equal
* to MaxAge, or it does not have a link back to vertex V,
* examine the next link in V's LSA.[23]
*/
if (w_lsa == NULL) {
if (IS_DEBUG_OSPF_EVENT)
zlog_debug("No LSA found");
continue;
}
if (IS_LSA_MAXAGE(w_lsa)) {
if (IS_DEBUG_OSPF_EVENT)
zlog_debug("LSA is MaxAge");
continue;
}
if (ospf_lsa_has_link(w_lsa->data, v->lsa) < 0) {
if (IS_DEBUG_OSPF_EVENT)
zlog_debug("The LSA doesn't have a link back");
continue;
}
/*
* (c) If vertex W is already on the shortest-path tree, examine
* the next link in the LSA.
*/
if (w_lsa->stat == LSA_SPF_IN_SPFTREE) {
if (IS_DEBUG_OSPF_EVENT)
zlog_debug("The LSA is already in SPF");
continue;
}
/*
* (d) Calculate the link state cost D of the resulting path
* from the root to vertex W. D is equal to the sum of the link
* state cost of the (already calculated) shortest path to
* vertex V and the advertised cost of the link between vertices
* V and W. If D is:
*/
/* calculate link cost D -- moved above */
/* Is there already vertex W in candidate list? */
if (w_lsa->stat == LSA_SPF_NOT_EXPLORED) {
/* prepare vertex W. */
w = ospf_vertex_new(area, w_lsa);
/* Calculate nexthop to W. */
if (ospf_nexthop_calculation(area, v, w, l, distance,
lsa_pos))
vertex_pqueue_add(candidate, w);
else {
listnode_delete(area->spf_vertex_list, w);
ospf_vertex_free(w);
w_lsa->stat = LSA_SPF_NOT_EXPLORED;
if (IS_DEBUG_OSPF_EVENT)
zlog_debug("Nexthop Calc failed");
}
} else if (w_lsa->stat != LSA_SPF_IN_SPFTREE) {
w = w_lsa->stat;
if (w->distance < distance) {
continue;
}
else if (w->distance == distance) {
/*
* Found an equal-cost path to W.
* Calculate nexthop of to W from V.
*/
ospf_nexthop_calculation(area, v, w, l,
distance, lsa_pos);
}
else {
/*
* Found a lower-cost path to W.
* nexthop_calculation is conditional, if it
* finds valid nexthop it will call
* spf_add_parents, which will flush the old
* parents.
*/
vertex_pqueue_del(candidate, w);
ospf_nexthop_calculation(area, v, w, l,
distance, lsa_pos);
vertex_pqueue_add(candidate, w);
}
} /* end W is already on the candidate list */
} /* end loop over the links in V's LSA */
}
static void ospf_spf_dump(struct vertex *v, int i)
{
struct listnode *cnode;
struct listnode *nnode;
struct vertex_parent *parent;
if (v->type == OSPF_VERTEX_ROUTER) {
if (IS_DEBUG_OSPF_EVENT)
zlog_debug("SPF Result: %d [R] %pI4", i,
&v->lsa->id);
} else {
struct network_lsa *lsa = (struct network_lsa *)v->lsa;
if (IS_DEBUG_OSPF_EVENT)
zlog_debug("SPF Result: %d [N] %pI4/%d", i,
&v->lsa->id,
ip_masklen(lsa->mask));
}
if (IS_DEBUG_OSPF_EVENT)
for (ALL_LIST_ELEMENTS_RO(v->parents, nnode, parent)) {
zlog_debug(" nexthop %p %pI4 %d",
(void *)parent->nexthop,
&parent->nexthop->router,
parent->nexthop->lsa_pos);
}
i++;
for (ALL_LIST_ELEMENTS_RO(v->children, cnode, v))
ospf_spf_dump(v, i);
}
void ospf_spf_print(struct vty *vty, struct vertex *v, int i)
{
struct listnode *cnode;
struct listnode *nnode;
struct vertex_parent *parent;
if (v->type == OSPF_VERTEX_ROUTER) {
vty_out(vty, "SPF Result: depth %d [R] %pI4\n", i, &v->lsa->id);
} else {
struct network_lsa *lsa = (struct network_lsa *)v->lsa;
vty_out(vty, "SPF Result: depth %d [N] %pI4/%d\n", i,
&v->lsa->id, ip_masklen(lsa->mask));
}
for (ALL_LIST_ELEMENTS_RO(v->parents, nnode, parent)) {
vty_out(vty,
" nexthop %pI4 lsa pos %d -- local nexthop %pI4 lsa pos %d\n",
&parent->nexthop->router, parent->nexthop->lsa_pos,
&parent->local_nexthop->router,
parent->local_nexthop->lsa_pos);
}
i++;
for (ALL_LIST_ELEMENTS_RO(v->children, cnode, v))
ospf_spf_print(vty, v, i);
}
/* Second stage of SPF calculation. */
static void ospf_spf_process_stubs(struct ospf_area *area, struct vertex *v,
struct route_table *rt, int parent_is_root)
{
struct listnode *cnode, *cnnode;
struct vertex *child;
if (IS_DEBUG_OSPF_EVENT)
zlog_debug("%s: processing stubs for area %pI4", __func__,
&area->area_id);
if (v->type == OSPF_VERTEX_ROUTER) {
uint8_t *p;
uint8_t *lim;
struct router_lsa_link *l;
struct router_lsa *router_lsa;
int lsa_pos = 0;
if (IS_DEBUG_OSPF_EVENT)
zlog_debug("%s: processing router LSA, id: %pI4",
__func__, &v->lsa->id);
router_lsa = (struct router_lsa *)v->lsa;
if (IS_DEBUG_OSPF_EVENT)
zlog_debug("%s: we have %d links to process", __func__,
ntohs(router_lsa->links));
p = ((uint8_t *)v->lsa) + OSPF_LSA_HEADER_SIZE + 4;
lim = ((uint8_t *)v->lsa) + ntohs(v->lsa->length);
while (p < lim) {
l = (struct router_lsa_link *)p;
p += (OSPF_ROUTER_LSA_LINK_SIZE
+ (l->m[0].tos_count * OSPF_ROUTER_LSA_TOS_SIZE));
/* Don't process TI-LFA protected resources */
if (l->m[0].type == LSA_LINK_TYPE_STUB
&& !ospf_spf_is_protected_resource(area, l, v->lsa))
ospf_intra_add_stub(rt, l, v, area,
parent_is_root, lsa_pos);
lsa_pos++;
}
}
ospf_vertex_dump("ospf_process_stubs(): after examining links: ", v, 1,
1);
for (ALL_LIST_ELEMENTS(v->children, cnode, cnnode, child)) {
if (CHECK_FLAG(child->flags, OSPF_VERTEX_PROCESSED))
continue;
/*
* The first level of routers connected to the root
* should have 'parent_is_root' set, including those
* connected via a network vertex.
*/
if (area->spf == v)
parent_is_root = 1;
else if (v->type == OSPF_VERTEX_ROUTER)
parent_is_root = 0;
ospf_spf_process_stubs(area, child, rt, parent_is_root);
SET_FLAG(child->flags, OSPF_VERTEX_PROCESSED);
}
}
void ospf_rtrs_free(struct route_table *rtrs)
{
struct route_node *rn;
struct list *or_list;
struct ospf_route * or ;
struct listnode *node, *nnode;
if (IS_DEBUG_OSPF_EVENT)
zlog_debug("Route: Router Routing Table free");
for (rn = route_top(rtrs); rn; rn = route_next(rn))
if ((or_list = rn->info) != NULL) {
for (ALL_LIST_ELEMENTS(or_list, node, nnode, or))
ospf_route_free(or);
list_delete(&or_list);
/* Unlock the node. */
rn->info = NULL;
route_unlock_node(rn);
}
route_table_finish(rtrs);
}
void ospf_spf_cleanup(struct vertex *spf, struct list *vertex_list)
{
/*
* Free nexthop information, canonical versions of which are
* attached the first level of router vertices attached to the
* root vertex, see ospf_nexthop_calculation.
*/
if (spf)
ospf_canonical_nexthops_free(spf);
/* Free SPF vertices list with deconstructor ospf_vertex_free. */
if (vertex_list)
list_delete(&vertex_list);
}
/* Calculating the shortest-path tree for an area, see RFC2328 16.1. */
void ospf_spf_calculate(struct ospf_area *area, struct ospf_lsa *root_lsa,
struct route_table *new_table,
struct route_table *all_rtrs,
struct route_table *new_rtrs, bool is_dry_run,
bool is_root_node)
{
struct vertex_pqueue_head candidate;
struct vertex *v;
if (IS_DEBUG_OSPF_EVENT) {
zlog_debug("%s: Start: running Dijkstra for area %pI4",
__func__, &area->area_id);
}
/*
* If the router LSA of the root is not yet allocated, return this
* area's calculation. In the 'usual' case the root_lsa is the
* self-originated router LSA of the node itself.
*/
if (!root_lsa) {
if (IS_DEBUG_OSPF_EVENT)
zlog_debug(
"%s: Skip area %pI4's calculation due to empty root LSA",
__func__, &area->area_id);
return;
}
/* Initialize the algorithm's data structures, see RFC2328 16.1. (1). */
/*
* This function scans all the LSA database and set the stat field to
* LSA_SPF_NOT_EXPLORED.
*/
lsdb_clean_stat(area->lsdb);
/* Create a new heap for the candidates. */
vertex_pqueue_init(&candidate);
/*
* Initialize the shortest-path tree to only the root (which is usually
* the router doing the calculation).
*/
ospf_spf_init(area, root_lsa, is_dry_run, is_root_node);
/* Set Area A's TransitCapability to false. */
area->transit = OSPF_TRANSIT_FALSE;
area->shortcut_capability = 1;
/*
* Use the root vertex for the start of the SPF algorithm and make it
* part of the tree.
*/
v = area->spf;
v->lsa_p->stat = LSA_SPF_IN_SPFTREE;
for (;;) {
/* RFC2328 16.1. (2). */
ospf_spf_next(v, area, &candidate);
/* RFC2328 16.1. (3). */
v = vertex_pqueue_pop(&candidate);
if (!v)
/* No more vertices left. */
break;
v->lsa_p->stat = LSA_SPF_IN_SPFTREE;
ospf_vertex_add_parent(v);
/* RFC2328 16.1. (4). */
if (v->type != OSPF_VERTEX_ROUTER)
ospf_intra_add_transit(new_table, v, area);
else {
if (new_rtrs)
ospf_intra_add_router(new_rtrs, v, area, false);
if (all_rtrs)
ospf_intra_add_router(all_rtrs, v, area, true);
}
/* Iterate back to (2), see RFC2328 16.1. (5). */
}
if (IS_DEBUG_OSPF_EVENT) {
ospf_spf_dump(area->spf, 0);
ospf_route_table_dump(new_table);
if (all_rtrs)
ospf_router_route_table_dump(all_rtrs);
}
/*
* Second stage of SPF calculation procedure's, add leaves to the tree
* for stub networks.
*/
ospf_spf_process_stubs(area, area->spf, new_table, 0);
ospf_vertex_dump(__func__, area->spf, 0, 1);
/* Increment SPF Calculation Counter. */
area->spf_calculation++;
monotime(&area->ospf->ts_spf);
area->ts_spf = area->ospf->ts_spf;
if (IS_DEBUG_OSPF_EVENT)
zlog_debug("%s: Stop. %zd vertices", __func__,
mtype_stats_alloc(MTYPE_OSPF_VERTEX));
}
void ospf_spf_calculate_area(struct ospf *ospf, struct ospf_area *area,
struct route_table *new_table,
struct route_table *all_rtrs,
struct route_table *new_rtrs)
{
ospf_spf_calculate(area, area->router_lsa_self, new_table, all_rtrs,
new_rtrs, false, true);
if (ospf->ti_lfa_enabled)
ospf_ti_lfa_compute(area, new_table,
ospf->ti_lfa_protection_type);
ospf_spf_cleanup(area->spf, area->spf_vertex_list);
area->spf = NULL;
area->spf_vertex_list = NULL;
}
void ospf_spf_calculate_areas(struct ospf *ospf, struct route_table *new_table,
struct route_table *all_rtrs,
struct route_table *new_rtrs)
{
struct ospf_area *area;
struct listnode *node, *nnode;
/* Calculate SPF for each area. */
for (ALL_LIST_ELEMENTS(ospf->areas, node, nnode, area)) {
/* Do backbone last, so as to first discover intra-area paths
* for any back-bone virtual-links */
if (ospf->backbone && ospf->backbone == area)
continue;
ospf_spf_calculate_area(ospf, area, new_table, all_rtrs,
new_rtrs);
}
/* SPF for backbone, if required */
if (ospf->backbone)
ospf_spf_calculate_area(ospf, ospf->backbone, new_table,
all_rtrs, new_rtrs);
}
/* Worker for SPF calculation scheduler. */
static void ospf_spf_calculate_schedule_worker(struct thread *thread)
{
struct ospf *ospf = THREAD_ARG(thread);
struct route_table *new_table, *new_rtrs;
struct route_table *all_rtrs = NULL;
struct timeval start_time, spf_start_time;
unsigned long ia_time, prune_time, rt_time;
unsigned long abr_time, total_spf_time, spf_time;
char rbuf[32]; /* reason_buf */
if (IS_DEBUG_OSPF_EVENT)
zlog_debug("SPF: Timer (SPF calculation expire)");
ospf->t_spf_calc = NULL;
ospf_vl_unapprove(ospf);
/* Execute SPF for each area including backbone, see RFC 2328 16.1. */
monotime(&spf_start_time);
new_table = route_table_init(); /* routing table */
new_rtrs = route_table_init(); /* ABR/ASBR routing table */
/* If we have opaque enabled then track all router reachability */
if (CHECK_FLAG(ospf->opaque, OPAQUE_OPERATION_READY_BIT))
all_rtrs = route_table_init();
ospf_spf_calculate_areas(ospf, new_table, all_rtrs, new_rtrs);
spf_time = monotime_since(&spf_start_time, NULL);
ospf_vl_shut_unapproved(ospf);
/* Calculate inter-area routes, see RFC 2328 16.2. */
monotime(&start_time);
ospf_ia_routing(ospf, new_table, new_rtrs);
ia_time = monotime_since(&start_time, NULL);
/* Get rid of transit networks and routers we cannot reach anyway. */
monotime(&start_time);
ospf_prune_unreachable_networks(new_table);
if (all_rtrs)
ospf_prune_unreachable_routers(all_rtrs);
ospf_prune_unreachable_routers(new_rtrs);
prune_time = monotime_since(&start_time, NULL);
/* Note: RFC 2328 16.3. is apparently missing. */
/*
* Calculate AS external routes, see RFC 2328 16.4.
* There is a dedicated routing table for external routes which is not
* handled here directly
*/
ospf_ase_calculate_schedule(ospf);
ospf_ase_calculate_timer_add(ospf);
if (IS_DEBUG_OSPF_EVENT)
zlog_debug(
"%s: ospf install new route, vrf %s id %u new_table count %lu",
__func__, ospf_vrf_id_to_name(ospf->vrf_id),
ospf->vrf_id, new_table->count);
/* Update routing table. */
monotime(&start_time);
ospf_route_install(ospf, new_table);
rt_time = monotime_since(&start_time, NULL);
/* Free old all routers routing table */
if (ospf->oall_rtrs) {
ospf_rtrs_free(ospf->oall_rtrs);
ospf->oall_rtrs = NULL;
}
/* Update all routers routing table */
ospf->oall_rtrs = ospf->all_rtrs;
ospf->all_rtrs = all_rtrs;
#ifdef SUPPORT_OSPF_API
ospf_apiserver_notify_reachable(ospf->oall_rtrs, ospf->all_rtrs);
#endif
/* Free old ABR/ASBR routing table */
if (ospf->old_rtrs) {
ospf_rtrs_free(ospf->old_rtrs);
ospf->old_rtrs = NULL;
}
/* Update ABR/ASBR routing table */
ospf->old_rtrs = ospf->new_rtrs;
ospf->new_rtrs = new_rtrs;
/* ABRs may require additional changes, see RFC 2328 16.7. */
monotime(&start_time);
if (IS_OSPF_ABR(ospf)) {
if (ospf->anyNSSA)
ospf_abr_nssa_check_status(ospf);
ospf_abr_task(ospf);
}
abr_time = monotime_since(&start_time, NULL);
/* Schedule Segment Routing update */
ospf_sr_update_task(ospf);
total_spf_time =
monotime_since(&spf_start_time, &ospf->ts_spf_duration);
rbuf[0] = '\0';
if (spf_reason_flags) {
if (spf_reason_flags & (1 << SPF_FLAG_ROUTER_LSA_INSTALL))
strlcat(rbuf, "R, ", sizeof(rbuf));
if (spf_reason_flags & (1 << SPF_FLAG_NETWORK_LSA_INSTALL))
strlcat(rbuf, "N, ", sizeof(rbuf));
if (spf_reason_flags & (1 << SPF_FLAG_SUMMARY_LSA_INSTALL))
strlcat(rbuf, "S, ", sizeof(rbuf));
if (spf_reason_flags & (1 << SPF_FLAG_ASBR_SUMMARY_LSA_INSTALL))
strlcat(rbuf, "AS, ", sizeof(rbuf));
if (spf_reason_flags & (1 << SPF_FLAG_ABR_STATUS_CHANGE))
strlcat(rbuf, "ABR, ", sizeof(rbuf));
if (spf_reason_flags & (1 << SPF_FLAG_ASBR_STATUS_CHANGE))
strlcat(rbuf, "ASBR, ", sizeof(rbuf));
if (spf_reason_flags & (1 << SPF_FLAG_MAXAGE))
strlcat(rbuf, "M, ", sizeof(rbuf));
if (spf_reason_flags & (1 << SPF_FLAG_GR_FINISH))
strlcat(rbuf, "GR, ", sizeof(rbuf));
size_t rbuflen = strlen(rbuf);
if (rbuflen >= 2)
rbuf[rbuflen - 2] = '\0'; /* skip the last ", " */
else
rbuf[0] = '\0';
}
if (IS_DEBUG_OSPF_EVENT) {
zlog_info("SPF Processing Time(usecs): %ld", total_spf_time);
zlog_info(" SPF Time: %ld", spf_time);
zlog_info(" InterArea: %ld", ia_time);
zlog_info(" Prune: %ld", prune_time);
zlog_info(" RouteInstall: %ld", rt_time);
if (IS_OSPF_ABR(ospf))
zlog_info(" ABR: %ld (%d areas)",
abr_time, ospf->areas->count);
zlog_info("Reason(s) for SPF: %s", rbuf);
}
ospf_clear_spf_reason_flags();
}
/*
* Add schedule for SPF calculation. To avoid frequenst SPF calc, we set timer
* for SPF calc.
*/
void ospf_spf_calculate_schedule(struct ospf *ospf, ospf_spf_reason_t reason)
{
unsigned long delay, elapsed, ht;
if (IS_DEBUG_OSPF_EVENT)
zlog_debug("SPF: calculation timer scheduled");
/* OSPF instance does not exist. */
if (ospf == NULL)
return;
ospf_spf_set_reason(reason);
/* SPF calculation timer is already scheduled. */
if (ospf->t_spf_calc) {
if (IS_DEBUG_OSPF_EVENT)
zlog_debug(
"SPF: calculation timer is already scheduled: %p",
(void *)ospf->t_spf_calc);
return;
}
elapsed = monotime_since(&ospf->ts_spf, NULL) / 1000;
ht = ospf->spf_holdtime * ospf->spf_hold_multiplier;
if (ht > ospf->spf_max_holdtime)
ht = ospf->spf_max_holdtime;
/* Get SPF calculation delay time. */
if (elapsed < ht) {
/*
* Got an event within the hold time of last SPF. We need to
* increase the hold_multiplier, if it's not already at/past
* maximum value, and wasn't already increased.
*/
if (ht < ospf->spf_max_holdtime)
ospf->spf_hold_multiplier++;
/* always honour the SPF initial delay */
if ((ht - elapsed) < ospf->spf_delay)
delay = ospf->spf_delay;
else
delay = ht - elapsed;
} else {
/* Event is past required hold-time of last SPF */
delay = ospf->spf_delay;
ospf->spf_hold_multiplier = 1;
}
if (IS_DEBUG_OSPF_EVENT)
zlog_debug("SPF: calculation timer delay = %ld msec", delay);
ospf->t_spf_calc = NULL;
thread_add_timer_msec(master, ospf_spf_calculate_schedule_worker, ospf,
delay, &ospf->t_spf_calc);
}
/* Restart OSPF SPF algorithm*/
void ospf_restart_spf(struct ospf *ospf)
{
if (IS_DEBUG_OSPF_EVENT)
zlog_debug("%s: Restart SPF.", __func__);
/* Handling inter area and intra area routes*/
if (ospf->new_table) {
ospf_route_delete(ospf, ospf->new_table);
ospf_route_table_free(ospf->new_table);
ospf->new_table = route_table_init();
}
/* Handling of TYPE-5 lsa(external routes) */
if (ospf->old_external_route) {
ospf_route_delete(ospf, ospf->old_external_route);
ospf_route_table_free(ospf->old_external_route);
ospf->old_external_route = route_table_init();
}
/* Trigger SPF */
ospf_spf_calculate_schedule(ospf, SPF_FLAG_CONFIG_CHANGE);
}
Reference in New Issue View Git Blame Copy Permalink