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bgpd: fix "bgp as-pah access-list" with "set aspath exclude" set/unse…
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…t issues

whith the following config

router bgp 65001
 no bgp ebgp-requires-policy
 neighbor 192.168.1.2 remote-as external
 neighbor 192.168.1.2 timers 3 10
 !
 address-family ipv4 unicast
  neighbor 192.168.1.2 route-map r2 in
 exit-address-family
exit
!
bgp as-path access-list FIRST seq 5 permit ^65
bgp as-path access-list SECOND seq 5 permit 2$
!
route-map r2 permit 6
 match ip address prefix-list p2
 set as-path exclude as-path-access-list SECOND
exit
!
route-map r2 permit 10
 match ip address prefix-list p1
 set as-path exclude 65003
exit
!
route-map r2 permit 20
 match ip address prefix-list p3
 set as-path exclude all
exit

making some
no bgp as-path access-list SECOND permit 2$
bgp as-path access-list SECOND permit 3$

clear bgp *

no bgp as-path access-list SECOND permit 3$
bgp as-path access-list SECOND permit 2$

clear bgp *

will induce some crashes

thus  we rework the links between aslists and aspath_exclude

Signed-off-by: Francois Dumontet <francois.dumontet@6wind.com>
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fdumontet6WIND committed May 16, 2024
1 parent db1e2a0 commit 094dcc3
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Showing 5 changed files with 108 additions and 59 deletions.
47 changes: 47 additions & 0 deletions bgpd/bgp_aspath.c
Original file line number Diff line number Diff line change
Expand Up @@ -77,6 +77,9 @@ static struct hash *ashash;
/* Stream for SNMP. See aspath_snmp_pathseg */
static struct stream *snmp_stream;

/* as-path orphan exclude list */
static struct as_list_list_head as_exclude_list_orphan;

/* Callers are required to initialize the memory */
static as_t *assegment_data_new(int num)
{
Expand Down Expand Up @@ -1558,6 +1561,38 @@ struct aspath *aspath_prepend(struct aspath *as1, struct aspath *as2)
/* Not reached */
}

/* insert aspath exclude in head of orphan exclude list*/
void as_exclude_set_orphan(struct aspath_exclude *ase)
{
ase->exclude_aspath_acl = NULL;
as_list_list_add_head(&as_exclude_list_orphan, ase);
}

void as_exclude_remove_orphan(struct aspath_exclude *ase)
{
if (as_list_list_count(&as_exclude_list_orphan))
as_list_list_del(&as_exclude_list_orphan, ase);
}

/* currently provide only one exclude, not a list */
struct aspath_exclude *as_exclude_lookup_orphan(const char *acl_name)
{
struct aspath_exclude *ase = NULL;
char *name = NULL;

frr_each (as_list_list, &as_exclude_list_orphan, ase) {
if (ase->exclude_aspath_acl_name) {
name = ase->exclude_aspath_acl_name;
if (!strcmp(name, acl_name))
break;
}
}
if (ase)
as_exclude_remove_orphan(ase);

return ase;
}

/* Iterate over AS_PATH segments and wipe all occurrences of the
* listed AS numbers. Hence some segments may lose some or even
* all data on the way, the operation is implemented as a smarter
Expand Down Expand Up @@ -2236,14 +2271,26 @@ void aspath_init(void)
{
ashash = hash_create_size(32768, aspath_key_make, aspath_cmp,
"BGP AS Path");

as_list_list_init(&as_exclude_list_orphan);
}

void aspath_finish(void)
{
struct aspath_exclude *ase;

hash_clean_and_free(&ashash, (void (*)(void *))aspath_free);

if (snmp_stream)
stream_free(snmp_stream);

while ((ase = as_list_list_pop(&as_exclude_list_orphan))) {
aspath_free(ase->aspath);
if (ase->exclude_aspath_acl_name)
XFREE(MTYPE_TMP, ase->exclude_aspath_acl_name);
XFREE(MTYPE_ROUTE_MAP_COMPILED, ase);
}
as_list_list_fini(&as_exclude_list_orphan);
}

/* return and as path value */
Expand Down
7 changes: 7 additions & 0 deletions bgpd/bgp_aspath.h
Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,7 @@
#include "lib/json.h"
#include "bgpd/bgp_route.h"
#include "bgpd/bgp_filter.h"
#include <typesafe.h>

/* AS path segment type. */
#define AS_SET 1
Expand Down Expand Up @@ -67,11 +68,14 @@ struct aspath {

/* `set as-path exclude ASn' */
struct aspath_exclude {
struct as_list_list_item exclude_list;
struct aspath *aspath;
bool exclude_all;
char *exclude_aspath_acl_name;
struct as_list *exclude_aspath_acl;
};
DECLARE_DLIST(as_list_list, struct aspath_exclude, exclude_list);


/* Prototypes. */
extern void aspath_init(void);
Expand All @@ -83,6 +87,9 @@ extern struct aspath *aspath_parse(struct stream *s, size_t length,
extern struct aspath *aspath_dup(struct aspath *aspath);
extern struct aspath *aspath_aggregate(struct aspath *as1, struct aspath *as2);
extern struct aspath *aspath_prepend(struct aspath *as1, struct aspath *as2);
extern void as_exclude_set_orphan(struct aspath_exclude *ase);
extern void as_exclude_remove_orphan(struct aspath_exclude *ase);
extern struct aspath_exclude *as_exclude_lookup_orphan(const char *acl_name);
extern struct aspath *aspath_filter_exclude(struct aspath *source,
struct aspath *exclude_list);
extern struct aspath *aspath_filter_exclude_all(struct aspath *source);
Expand Down
41 changes: 25 additions & 16 deletions bgpd/bgp_filter.c
Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,7 @@
#include "bgpd/bgp_aspath.h"
#include "bgpd/bgp_regex.h"

/* List of AS filter list. */
/* List of AS list. */
struct as_list_list {
struct as_list *head;
struct as_list *tail;
Expand Down Expand Up @@ -205,14 +205,6 @@ static struct as_list *as_list_new(void)

static void as_list_free(struct as_list *aslist)
{
struct aspath_exclude_list *cur_bp = aslist->exclude_list;
struct aspath_exclude_list *next_bp = NULL;

while (cur_bp) {
next_bp = cur_bp->next;
XFREE(MTYPE_ROUTE_MAP_COMPILED, cur_bp);
cur_bp = next_bp;
}

XFREE (MTYPE_AS_STR, aslist->name);
XFREE (MTYPE_AS_LIST, aslist);
Expand Down Expand Up @@ -299,7 +291,6 @@ static void as_list_delete(struct as_list *aslist)
{
struct as_list_list *list;
struct as_filter *filter, *next;
struct aspath_exclude_list *cur_bp;

for (filter = aslist->head; filter; filter = next) {
next = filter->next;
Expand All @@ -318,12 +309,6 @@ static void as_list_delete(struct as_list *aslist)
else
list->head = aslist->next;

cur_bp = aslist->exclude_list;
while (cur_bp) {
cur_bp->bp_as_excl->exclude_aspath_acl = NULL;
cur_bp = cur_bp->next;
}

as_list_free(aslist);
}

Expand Down Expand Up @@ -431,6 +416,7 @@ DEFUN(as_path, bgp_as_path_cmd,
enum as_filter_type type;
struct as_filter *asfilter;
struct as_list *aslist;
struct aspath_exclude *ase;
regex_t *regex;
char *regstr;
int64_t seqnum = ASPATH_SEQ_NUMBER_AUTO;
Expand Down Expand Up @@ -482,6 +468,22 @@ DEFUN(as_path, bgp_as_path_cmd,
else
as_list_filter_add(aslist, asfilter);

/* init the exclude rule list*/
as_list_list_init(&aslist->exclude_rule);

/* get aspath orphan exclude that are using this acl */
ase = as_exclude_lookup_orphan(alname);
if (ase) {
as_list_list_add_head(&aslist->exclude_rule, ase);
/* set reverse pointer */
ase->exclude_aspath_acl = aslist;
/* set list of aspath excludes using that acl */
while ((ase = as_exclude_lookup_orphan(alname))) {
as_list_list_add_head(&aslist->exclude_rule, ase);
ase->exclude_aspath_acl = aslist;
}
}

return CMD_SUCCESS;
}

Expand All @@ -502,6 +504,7 @@ DEFUN(no_as_path, no_bgp_as_path_cmd,
enum as_filter_type type;
struct as_filter *asfilter;
struct as_list *aslist;
struct aspath_exclude *ase;
char *regstr;
regex_t *regex;

Expand Down Expand Up @@ -556,6 +559,12 @@ DEFUN(no_as_path, no_bgp_as_path_cmd,

XFREE(MTYPE_TMP, regstr);

/* put aspath exclude list into orphan */
if (as_list_list_count(&aslist->exclude_rule))
while ((ase = as_list_list_pop(&aslist->exclude_rule)))
as_exclude_set_orphan(ase);

as_list_list_fini(&aslist->exclude_rule);
as_list_filter_delete(aslist, asfilter);

return CMD_SUCCESS;
Expand Down
13 changes: 6 additions & 7 deletions bgpd/bgp_filter.h
Original file line number Diff line number Diff line change
Expand Up @@ -6,11 +6,12 @@
#ifndef _QUAGGA_BGP_FILTER_H
#define _QUAGGA_BGP_FILTER_H

#include <typesafe.h>

#define ASPATH_SEQ_NUMBER_AUTO -1

enum as_filter_type { AS_FILTER_DENY, AS_FILTER_PERMIT };


/* Element of AS path filter. */
struct as_filter {
struct as_filter *next;
Expand All @@ -25,11 +26,7 @@ struct as_filter {
int64_t seq;
};

struct aspath_exclude_list {
struct aspath_exclude_list *next;
struct aspath_exclude *bp_as_excl;
};

PREDECL_DLIST(as_list_list);
/* AS path filter list. */
struct as_list {
char *name;
Expand All @@ -39,7 +36,9 @@ struct as_list {

struct as_filter *head;
struct as_filter *tail;
struct aspath_exclude_list *exclude_list;

/* Changes in AS path */
struct as_list_list_head exclude_rule;
};


Expand Down
59 changes: 23 additions & 36 deletions bgpd/bgp_routemap.c
Original file line number Diff line number Diff line change
Expand Up @@ -2325,7 +2325,7 @@ static const struct route_map_rule_cmd route_set_aspath_prepend_cmd = {
static void *route_aspath_exclude_compile(const char *arg)
{
struct aspath_exclude *ase;
struct aspath_exclude_list *ael;
struct as_list *aux_aslist;
const char *str = arg;
static const char asp_acl[] = "as-path-access-list";

Expand All @@ -2337,44 +2337,37 @@ static void *route_aspath_exclude_compile(const char *arg)
while (*str == ' ')
str++;
ase->exclude_aspath_acl_name = XSTRDUP(MTYPE_TMP, str);
ase->exclude_aspath_acl = as_list_lookup(str);
aux_aslist = as_list_lookup(str);
if (!aux_aslist)
/* new orphan filter */
as_exclude_set_orphan(ase);
else
as_list_list_add_head(&aux_aslist->exclude_rule, ase);

ase->exclude_aspath_acl = aux_aslist;
} else
ase->aspath = aspath_str2aspath(str, bgp_get_asnotation(NULL));

if (ase->exclude_aspath_acl) {
ael = XCALLOC(MTYPE_ROUTE_MAP_COMPILED,
sizeof(struct aspath_exclude_list));
ael->bp_as_excl = ase;
ael->next = ase->exclude_aspath_acl->exclude_list;
ase->exclude_aspath_acl->exclude_list = ael;
}

return ase;
}

static void route_aspath_exclude_free(void *rule)
{
struct aspath_exclude *ase = rule;
struct aspath_exclude_list *cur_ael = NULL;
struct aspath_exclude_list *prev_ael = NULL;
struct as_list *acl;

/* manage references to that rule*/
if (ase->exclude_aspath_acl) {
acl = ase->exclude_aspath_acl;
as_list_list_del(&acl->exclude_rule, ase);
} else {
/* no ref to acl, this aspath exclude is orphan */
as_exclude_remove_orphan(ase);
}

aspath_free(ase->aspath);
if (ase->exclude_aspath_acl_name)
XFREE(MTYPE_TMP, ase->exclude_aspath_acl_name);
if (ase->exclude_aspath_acl)
cur_ael = ase->exclude_aspath_acl->exclude_list;
while (cur_ael) {
if (cur_ael->bp_as_excl == ase) {
if (prev_ael)
prev_ael->next = cur_ael->next;
else
ase->exclude_aspath_acl->exclude_list = NULL;
XFREE(MTYPE_ROUTE_MAP_COMPILED, cur_ael);
break;
}
prev_ael = cur_ael;
cur_ael = cur_ael->next;
}
XFREE(MTYPE_ROUTE_MAP_COMPILED, ase);
}

Expand Down Expand Up @@ -2409,16 +2402,10 @@ route_set_aspath_exclude(void *rule, const struct prefix *dummy, void *object)
else if (ase->exclude_all)
path->attr->aspath = aspath_filter_exclude_all(new_path);

else if (ase->exclude_aspath_acl_name) {
if (!ase->exclude_aspath_acl)
ase->exclude_aspath_acl =
as_list_lookup(ase->exclude_aspath_acl_name);
if (ase->exclude_aspath_acl)
path->attr->aspath =
aspath_filter_exclude_acl(new_path,
ase->exclude_aspath_acl);
}

else if (ase->exclude_aspath_acl)
path->attr->aspath =
aspath_filter_exclude_acl(new_path,
ase->exclude_aspath_acl);
return RMAP_OKAY;
}

Expand Down

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