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bgpd: fix incorrect usage of slist in dampening
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Current code is a complete misuse of SLIST structure. Instead of just
adding a SLIST_ENTRY to struct bgp_damp_info, it allocates a separate
structure to be a node in the list.

Signed-off-by: Igor Ryzhov <iryzhov@nfware.com>
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@idryzhov @ton31337
idryzhov authored and ton31337 committed May 3, 2024
1 parent 4c500d6 commit 1d37871
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Showing 2 changed files with 26 additions and 89 deletions.
108 changes: 24 additions & 84 deletions bgpd/bgp_damp.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -24,72 +24,32 @@

static void bgp_reuselist_add(struct reuselist *list, struct bgp_damp_info *info)
{
struct reuselist_node *new_node;

assert(info);
new_node = XCALLOC(MTYPE_BGP_DAMP_REUSELIST, sizeof(*new_node));
new_node->info = info;
SLIST_INSERT_HEAD(list, new_node, entry);
SLIST_INSERT_HEAD(list, info, entry);
}

static void bgp_reuselist_del(struct reuselist *list,
struct reuselist_node **node)
static void bgp_reuselist_del(struct reuselist *list, struct bgp_damp_info *info)
{
if ((*node) == NULL)
return;
assert(list && node && *node);
SLIST_REMOVE(list, (*node), reuselist_node, entry);
XFREE(MTYPE_BGP_DAMP_REUSELIST, (*node));
*node = NULL;
assert(info);
SLIST_REMOVE(list, info, bgp_damp_info, entry);
}

static void bgp_reuselist_switch(struct reuselist *source,
struct reuselist_node *node,
struct bgp_damp_info *info,
struct reuselist *target)
{
assert(source && target && node);
SLIST_REMOVE(source, node, reuselist_node, entry);
SLIST_INSERT_HEAD(target, node, entry);
}

static void bgp_reuselist_free(struct reuselist *list)
{
struct reuselist_node *rn;

assert(list);
while ((rn = SLIST_FIRST(list)) != NULL)
bgp_reuselist_del(list, &rn);
}

static struct reuselist_node *bgp_reuselist_find(struct reuselist *list,
struct bgp_damp_info *info)
{
struct reuselist_node *rn;

assert(list && info);
SLIST_FOREACH (rn, list, entry) {
if (rn->info == info)
return rn;
}
return NULL;
assert(source && target && info);
SLIST_REMOVE(source, info, bgp_damp_info, entry);
SLIST_INSERT_HEAD(target, info, entry);
}

static void bgp_damp_info_unclaim(struct bgp_damp_info *bdi)
{
struct reuselist_node *node;

assert(bdi && bdi->config);
if (bdi->index == BGP_DAMP_NO_REUSE_LIST_INDEX) {
node = bgp_reuselist_find(&bdi->config->no_reuse_list, bdi);
if (node)
bgp_reuselist_del(&bdi->config->no_reuse_list, &node);
} else {
node = bgp_reuselist_find(&bdi->config->reuse_list[bdi->index],
bdi);
if (node)
bgp_reuselist_del(&bdi->config->reuse_list[bdi->index],
&node);
}
if (bdi->index == BGP_DAMP_NO_REUSE_LIST_INDEX)
bgp_reuselist_del(&bdi->config->no_reuse_list, bdi);
else
bgp_reuselist_del(&bdi->config->reuse_list[bdi->index], bdi);
bdi->config = NULL;
}

Expand Down Expand Up @@ -170,19 +130,9 @@ static void bgp_no_reuse_list_add(struct bgp_damp_info *bdi,
bgp_reuselist_add(&bdc->no_reuse_list, bdi);
}

static void bgp_no_reuse_list_delete(struct bgp_damp_info *bdi,
struct bgp_damp_config *bdc)
static void bgp_no_reuse_list_delete(struct bgp_damp_info *bdi)
{
struct reuselist_node *rn;

assert(bdc && bdi);
if (bdi->config == NULL) {
bgp_damp_info_unclaim(bdi);
return;
}
bdi->config = NULL;
rn = bgp_reuselist_find(&bdc->no_reuse_list, bdi);
bgp_reuselist_del(&bdc->no_reuse_list, &rn);
bgp_damp_info_unclaim(bdi);
}

/* Return decayed penalty value. */
Expand All @@ -207,7 +157,6 @@ static void bgp_reuse_timer(struct event *t)
{
struct bgp_damp_info *bdi;
struct reuselist plist;
struct reuselist_node *node;
struct bgp *bgp;
time_t t_now, t_diff;
struct bgp_damp_config *bdc = EVENT_ARG(t);
Expand All @@ -230,8 +179,7 @@ static void bgp_reuse_timer(struct event *t)
assert(bdc->reuse_offset < bdc->reuse_list_size);

/* 3. if ( the saved list head pointer is non-empty ) */
while ((node = SLIST_FIRST(&plist)) != NULL) {
bdi = node->info;
while ((bdi = SLIST_FIRST(&plist)) != NULL) {
bgp = bdi->path->peer->bgp;

/* Set t-diff = t-now - t-updated. */
Expand Down Expand Up @@ -262,20 +210,19 @@ static void bgp_reuse_timer(struct event *t)
}

if (bdi->penalty <= bdc->reuse_limit / 2.0) {
bgp_reuselist_del(&plist, bdi);
bgp_damp_info_free(bdi, bdc, 1, bdi->afi,
bdi->safi);
bgp_reuselist_del(&plist, &node);
} else {
node->info->index =
BGP_DAMP_NO_REUSE_LIST_INDEX;
bgp_reuselist_switch(&plist, node,
bdi->index = BGP_DAMP_NO_REUSE_LIST_INDEX;
bgp_reuselist_switch(&plist, bdi,
&bdc->no_reuse_list);
}
} else {
/* Re-insert into another list (See RFC2439 Section
* 4.8.6). */
bdi->index = bgp_reuse_index(bdi->penalty, bdc);
bgp_reuselist_switch(&plist, node,
bgp_reuselist_switch(&plist, bdi,
&bdc->reuse_list[bdi->index]);
}
}
Expand Down Expand Up @@ -369,7 +316,7 @@ int bgp_damp_withdraw(struct bgp_path_info *path, struct bgp_dest *dest,
if (bdi->penalty >= bdc->suppress_value) {
bgp_path_info_set_flag(dest, path, BGP_PATH_DAMPED);
bdi->suppress_time = t_now;
bgp_no_reuse_list_delete(bdi, bdc);
bgp_no_reuse_list_delete(bdi);
bgp_reuse_list_add(bdi, bdc);
}
return BGP_DAMP_USED;
Expand Down Expand Up @@ -536,15 +483,13 @@ void bgp_damp_info_clean(struct bgp *bgp, struct bgp_damp_config *bdc,
afi_t afi, safi_t safi)
{
struct bgp_damp_info *bdi;
struct reuselist_node *rn;
struct reuselist *list;
unsigned int i;

bdc->reuse_offset = 0;
for (i = 0; i < bdc->reuse_list_size; ++i) {
list = &bdc->reuse_list[i];
while ((rn = SLIST_FIRST(list)) != NULL) {
bdi = rn->info;
while ((bdi = SLIST_FIRST(list)) != NULL) {
if (bdi->lastrecord == BGP_RECORD_UPDATE) {
bgp_aggregate_increment(bgp,
bgp_dest_get_prefix(
Expand All @@ -554,14 +499,13 @@ void bgp_damp_info_clean(struct bgp *bgp, struct bgp_damp_config *bdc,
bgp_process(bgp, bdi->dest, bdi->path, bdi->afi,
bdi->safi);
}
bgp_reuselist_del(list, &rn);
bgp_reuselist_del(list, bdi);
bgp_damp_info_free(bdi, bdc, 1, afi, safi);
}
}

while ((rn = SLIST_FIRST(&bdc->no_reuse_list)) != NULL) {
bdi = rn->info;
bgp_reuselist_del(&bdc->no_reuse_list, &rn);
while ((bdi = SLIST_FIRST(&bdc->no_reuse_list)) != NULL) {
bgp_reuselist_del(&bdc->no_reuse_list, bdi);
bgp_damp_info_free(bdi, bdc, 1, afi, safi);
}

Expand All @@ -573,10 +517,6 @@ void bgp_damp_info_clean(struct bgp *bgp, struct bgp_damp_config *bdc,
XFREE(MTYPE_BGP_DAMP_ARRAY, bdc->reuse_index);
bdc->reuse_index_size = 0;

/* Free reuse list array. */
for (i = 0; i < bdc->reuse_list_size; ++i)
bgp_reuselist_free(&bdc->reuse_list[i]);

XFREE(MTYPE_BGP_DAMP_ARRAY, bdc->reuse_list);
bdc->reuse_list_size = 0;

Expand Down
7 changes: 2 additions & 5 deletions bgpd/bgp_damp.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -46,14 +46,11 @@ struct bgp_damp_info {

afi_t afi;
safi_t safi;
};

struct reuselist_node {
SLIST_ENTRY(reuselist_node) entry;
struct bgp_damp_info *info;
SLIST_ENTRY(bgp_damp_info) entry;
};

SLIST_HEAD(reuselist, reuselist_node);
SLIST_HEAD(reuselist, bgp_damp_info);

/* Specified parameter set configuration. */
struct bgp_damp_config {
Expand Down

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