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BGP: Add option to reject AS_SETs

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There is a pending draft to make them obsolete
This commit is contained in:
Ondrej Zajicek (work) 2019-11-04 22:07:03 +01:00
parent 0edf0c8cd9
commit a52476c9be
5 changed files with 22 additions and 7 deletions
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14
nest/a-path.c
View file

@ -25,7 +25,7 @@
#define BAD(DSC, VAL) ({ err_dsc = DSC; err_val = VAL; goto bad; })
int
as_path_valid(byte *data, uint len, int bs, int confed, char *err, uint elen)
as_path_valid(byte *data, uint len, int bs, int sets, int confed, char *err, uint elen)
{
byte *pos = data;
char *err_dsc = NULL;
@ -46,13 +46,21 @@ as_path_valid(byte *data, uint len, int bs, int confed, char *err, uint elen)
switch (type)
{
case AS_PATH_SET:
if (!sets)
BAD("AS_SET segment", type);
break;
case AS_PATH_SEQUENCE:
break;
case AS_PATH_CONFED_SEQUENCE:
case AS_PATH_CONFED_SET:
if (!confed)
BAD("AS_CONFED* segment", type);
BAD("AS_CONFED_SEQUENCE segment", type);
break;
case AS_PATH_CONFED_SET:
if (!sets || !confed)
BAD("AS_CONFED_SET segment", type);
break;
default:

2
nest/attrs.h
View file

@ -30,7 +30,7 @@
struct f_tree;
int as_path_valid(byte *data, uint len, int bs, int confed, char *err, uint elen);
int as_path_valid(byte *data, uint len, int bs, int sets, int confed, char *err, uint elen);
int as_path_16to32(byte *dst, const byte *src, uint len);
int as_path_32to16(byte *dst, const byte *src, uint len);
int as_path_contains_as4(const struct adata *path);

8
proto/bgp/attrs.c
View file

@ -426,10 +426,11 @@ bgp_decode_as_path(struct bgp_parse_state *s, uint code UNUSED, uint flags, byte
{
struct bgp_proto *p = s->proto;
int as_length = s->as4_session ? 4 : 2;
int as_sets = p->cf->allow_as_sets;
int as_confed = p->cf->confederation && p->is_interior;
char err[128];
if (!as_path_valid(data, len, as_length, as_confed, err, sizeof(err)))
if (!as_path_valid(data, len, as_length, as_sets, as_confed, err, sizeof(err)))
WITHDRAW("Malformed AS_PATH attribute - %s", err);
/* In some circumstances check for initial AS_CONFED_SEQUENCE; RFC 5065 5.0 */
@ -763,6 +764,9 @@ bgp_decode_as4_aggregator(struct bgp_parse_state *s, uint code UNUSED, uint flag
static void
bgp_decode_as4_path(struct bgp_parse_state *s, uint code UNUSED, uint flags, byte *data, uint len, ea_list **to)
{
struct bgp_proto *p = s->proto;
int sets = p->cf->allow_as_sets;
char err[128];
if (s->as4_session)
@ -771,7 +775,7 @@ bgp_decode_as4_path(struct bgp_parse_state *s, uint code UNUSED, uint flags, byt
if (len < 6)
DISCARD(BAD_LENGTH, "AS4_PATH", len);
if (!as_path_valid(data, len, 4, 1, err, sizeof(err)))
if (!as_path_valid(data, len, 4, sets, 1, err, sizeof(err)))
DISCARD("Malformed AS4_PATH attribute - %s", err);
struct adata *a = lp_alloc_adata(s->pool, len);

1
proto/bgp/bgp.h
View file

@ -107,6 +107,7 @@ struct bgp_config {
int interpret_communities; /* Hardwired handling of well-known communities */
int allow_local_as; /* Allow that number of local ASNs in incoming AS_PATHs */
int allow_local_pref; /* Allow LOCAL_PREF in EBGP sessions */
int allow_as_sets; /* Allow AS_SETs in incoming AS_PATHs */
int gr_mode; /* Graceful restart mode (BGP_GR_*) */
int llgr_mode; /* Long-lived graceful restart mode (BGP_LLGR_*) */
int setkey; /* Set MD5 password to system SA/SP database */

4
proto/bgp/config.Y
View file

@ -29,7 +29,7 @@ CF_KEYWORDS(BGP, LOCAL, NEIGHBOR, AS, HOLD, TIME, CONNECT, RETRY, KEEPALIVE,
SECURITY, DETERMINISTIC, SECONDARY, ALLOW, BFD, ADD, PATHS, RX, TX,
GRACEFUL, RESTART, AWARE, CHECK, LINK, PORT, EXTENDED, MESSAGES, SETKEY,
STRICT, BIND, CONFEDERATION, MEMBER, MULTICAST, FLOW4, FLOW6, LONG,
LIVED, STALE, IMPORT, IBGP, EBGP, MANDATORY, INTERNAL, EXTERNAL,
LIVED, STALE, IMPORT, IBGP, EBGP, MANDATORY, INTERNAL, EXTERNAL, SETS,
DYNAMIC, RANGE, NAME, DIGITS, BGP_AIGP, AIGP, ORIGINATE, COST)
%type <i> bgp_nh
@ -63,6 +63,7 @@ bgp_proto_start: proto_start BGP {
BGP_CFG->enable_as4 = 1;
BGP_CFG->capabilities = 2;
BGP_CFG->interpret_communities = 1;
BGP_CFG->allow_as_sets = 1;
BGP_CFG->default_local_pref = 100;
BGP_CFG->gr_mode = BGP_GR_AWARE;
BGP_CFG->gr_time = 120;
@ -179,6 +180,7 @@ bgp_proto:
| bgp_proto ALLOW LOCAL AS ';' { BGP_CFG->allow_local_as = -1; }
| bgp_proto ALLOW LOCAL AS expr ';' { BGP_CFG->allow_local_as = $5; }
| bgp_proto ALLOW BGP_LOCAL_PREF bool ';' { BGP_CFG->allow_local_pref = $4; }
| bgp_proto ALLOW AS SETS bool ';' { BGP_CFG->allow_as_sets = $5; }
| bgp_proto GRACEFUL RESTART bool ';' { BGP_CFG->gr_mode = $4; }
| bgp_proto GRACEFUL RESTART AWARE ';' { BGP_CFG->gr_mode = BGP_GR_AWARE; }
| bgp_proto GRACEFUL RESTART TIME expr ';' { BGP_CFG->gr_time = $5; }