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bgpd: fix AIGP calculation in route advertisement

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Currently the AIGP is always incremented when a route with the
attribute is advertised. That is incorrect when the nexthop is
unchanged, as is commonly the case in route reflection.

Adjust the AIGP for propagation only when the nexthop is set
to ourselves.

Signed-off-by: Enke Chen <enchen@paloaltonetworks.com>
This commit is contained in:
Enke Chen 2024-10-21 18:03:08 -07:00
parent 7e7f65cc00
commit fc82d7750f
5 changed files with 43 additions and 35 deletions
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27
bgpd/bgp_attr.c
View file

@ -480,12 +480,11 @@ static bool bgp_attr_aigp_get_tlv_metric(uint8_t *pnt, int length,
return false; return false;
} }
static void stream_put_bgp_aigp_tlv_metric(struct stream *s, static void stream_put_bgp_aigp_tlv_metric(struct stream *s, uint64_t aigp)
struct bgp_path_info *bpi)
{ {
stream_putc(s, BGP_AIGP_TLV_METRIC); stream_putc(s, BGP_AIGP_TLV_METRIC);
stream_putw(s, BGP_AIGP_TLV_METRIC_LEN); stream_putw(s, BGP_AIGP_TLV_METRIC_LEN);
stream_putq(s, bgp_aigp_metric_total(bpi)); stream_putq(s, aigp);
} }
static bool bgp_attr_aigp_valid(uint8_t *pnt, int length) static bool bgp_attr_aigp_valid(uint8_t *pnt, int length)
@ -4546,14 +4545,11 @@ static void bgp_packet_ecommunity_attribute(struct stream *s, struct peer *peer,
} }
/* Make attribute packet. */ /* Make attribute packet. */
bgp_size_t bgp_packet_attribute(struct bgp *bgp, struct peer *peer, bgp_size_t bgp_packet_attribute(struct bgp *bgp, struct peer *peer, struct stream *s,
struct stream *s, struct attr *attr, struct attr *attr, struct bpacket_attr_vec_arr *vecarr,
struct bpacket_attr_vec_arr *vecarr, struct prefix *p, afi_t afi, safi_t safi, struct peer *from,
struct prefix *p, afi_t afi, safi_t safi, struct prefix_rd *prd, mpls_label_t *label, uint8_t num_labels,
struct peer *from, struct prefix_rd *prd, bool addpath_capable, uint32_t addpath_tx_id)
mpls_label_t *label, uint8_t num_labels,
bool addpath_capable, uint32_t addpath_tx_id,
struct bgp_path_info *bpi)
{ {
size_t cp; size_t cp;
size_t aspath_sizep; size_t aspath_sizep;
@ -5032,10 +5028,7 @@ bgp_size_t bgp_packet_attribute(struct bgp *bgp, struct peer *peer,
} }
/* AIGP */ /* AIGP */
if (bpi && CHECK_FLAG(attr->flag, ATTR_FLAG_BIT(BGP_ATTR_AIGP)) && if (CHECK_FLAG(attr->flag, ATTR_FLAG_BIT(BGP_ATTR_AIGP)) && AIGP_TRANSMIT_ALLOWED(peer)) {
(CHECK_FLAG(peer->flags, PEER_FLAG_AIGP) ||
peer->sub_sort == BGP_PEER_EBGP_OAD ||
peer->sort != BGP_PEER_EBGP)) {
/* At the moment only AIGP Metric TLV exists for AIGP /* At the moment only AIGP Metric TLV exists for AIGP
* attribute. If more comes in, do not forget to update * attribute. If more comes in, do not forget to update
* attr_len variable to include new ones. * attr_len variable to include new ones.
@ -5045,7 +5038,7 @@ bgp_size_t bgp_packet_attribute(struct bgp *bgp, struct peer *peer,
stream_putc(s, BGP_ATTR_FLAG_OPTIONAL); stream_putc(s, BGP_ATTR_FLAG_OPTIONAL);
stream_putc(s, BGP_ATTR_AIGP); stream_putc(s, BGP_ATTR_AIGP);
stream_putc(s, attr_len); stream_putc(s, attr_len);
stream_put_bgp_aigp_tlv_metric(s, bpi); stream_put_bgp_aigp_tlv_metric(s, attr->aigp_metric);
} }
/* Unknown transit attribute. */ /* Unknown transit attribute. */
@ -5314,7 +5307,7 @@ void bgp_dump_routes_attr(struct stream *s, struct bgp_path_info *bpi,
stream_putc(s, BGP_ATTR_FLAG_OPTIONAL | BGP_ATTR_FLAG_TRANS); stream_putc(s, BGP_ATTR_FLAG_OPTIONAL | BGP_ATTR_FLAG_TRANS);
stream_putc(s, BGP_ATTR_AIGP); stream_putc(s, BGP_ATTR_AIGP);
stream_putc(s, attr_len); stream_putc(s, attr_len);
stream_put_bgp_aigp_tlv_metric(s, bpi); stream_put_bgp_aigp_tlv_metric(s, attr->aigp_metric);
} }
/* Return total size of attribute. */ /* Return total size of attribute. */

16
bgpd/bgp_attr.h
View file

@ -387,12 +387,12 @@ extern struct attr *bgp_attr_aggregate_intern(
struct community *community, struct ecommunity *ecommunity, struct community *community, struct ecommunity *ecommunity,
struct lcommunity *lcommunity, struct bgp_aggregate *aggregate, struct lcommunity *lcommunity, struct bgp_aggregate *aggregate,
uint8_t atomic_aggregate, const struct prefix *p); uint8_t atomic_aggregate, const struct prefix *p);
extern bgp_size_t bgp_packet_attribute( extern bgp_size_t bgp_packet_attribute(struct bgp *bgp, struct peer *peer, struct stream *s,
struct bgp *bgp, struct peer *peer, struct stream *s, struct attr *attr, struct attr *attr, struct bpacket_attr_vec_arr *vecarr,
struct bpacket_attr_vec_arr *vecarr, struct prefix *p, afi_t afi, struct prefix *p, afi_t afi, safi_t safi, struct peer *from,
safi_t safi, struct peer *from, struct prefix_rd *prd, struct prefix_rd *prd, mpls_label_t *label,
mpls_label_t *label, uint8_t num_labels, bool addpath_capable, uint8_t num_labels, bool addpath_capable,
uint32_t addpath_tx_id, struct bgp_path_info *bpi); uint32_t addpath_tx_id);
extern void bgp_dump_routes_attr(struct stream *s, struct bgp_path_info *bpi, extern void bgp_dump_routes_attr(struct stream *s, struct bgp_path_info *bpi,
const struct prefix *p); const struct prefix *p);
extern bool attrhash_cmp(const void *arg1, const void *arg2); extern bool attrhash_cmp(const void *arg1, const void *arg2);
@ -585,6 +585,10 @@ static inline void bgp_attr_set_transit(struct attr *attr,
attr->transit = transit; attr->transit = transit;
} }
#define AIGP_TRANSMIT_ALLOWED(peer) \
(CHECK_FLAG((peer)->flags, PEER_FLAG_AIGP) || ((peer)->sub_sort == BGP_PEER_EBGP_OAD) || \
((peer)->sort != BGP_PEER_EBGP))
static inline uint64_t bgp_attr_get_aigp_metric(const struct attr *attr) static inline uint64_t bgp_attr_get_aigp_metric(const struct attr *attr)
{ {
return attr->aigp_metric; return attr->aigp_metric;

5
bgpd/bgp_bmp.c
View file

@ -1016,9 +1016,8 @@ static struct stream *bmp_update(const struct prefix *p, struct prefix_rd *prd,
stream_putw(s, 0); stream_putw(s, 0);
/* 5: Encode all the attributes, except MP_REACH_NLRI attr. */ /* 5: Encode all the attributes, except MP_REACH_NLRI attr. */
total_attr_len = total_attr_len = bgp_packet_attribute(NULL, peer, s, attr, &vecarr, NULL, afi, safi, peer,
bgp_packet_attribute(NULL, peer, s, attr, &vecarr, NULL, afi, NULL, NULL, 0, 0, 0);
safi, peer, NULL, NULL, 0, 0, 0, NULL);
/* space check? */ /* space check? */

15
bgpd/bgp_route.c
View file

@ -2821,6 +2821,21 @@ bool subgroup_announce_check(struct bgp_dest *dest, struct bgp_path_info *pi,
false)); false));
} }
/*
* Adjust AIGP for propagation when the nexthop is set to ourselves,
* e.g., using "set ip nexthop peer-address" or when advertising to
* EBGP. Note in route reflection the nexthop is usually unmodified
* and the AIGP should not be adjusted in that case.
*/
if (CHECK_FLAG(attr->flag, ATTR_FLAG_BIT(BGP_ATTR_AIGP)) && AIGP_TRANSMIT_ALLOWED(peer)) {
if (nh_reset ||
CHECK_FLAG(attr->rmap_change_flags, BATTR_RMAP_NEXTHOP_PEER_ADDRESS)) {
uint64_t aigp = bgp_aigp_metric_total(pi);
bgp_attr_set_aigp_metric(attr, aigp);
}
}
return true; return true;
} }

15
bgpd/bgp_updgrp_packet.c
View file

@ -738,9 +738,9 @@ struct bpacket *subgroup_update_packet(struct update_subgroup *subgrp)
/* 5: Encode all the attributes, except MP_REACH_NLRI /* 5: Encode all the attributes, except MP_REACH_NLRI
* attr. */ * attr. */
total_attr_len = bgp_packet_attribute( total_attr_len = bgp_packet_attribute(NULL, peer, s, adv->baa->attr,
NULL, peer, s, adv->baa->attr, &vecarr, NULL, &vecarr, NULL, afi, safi, from, NULL,
afi, safi, from, NULL, NULL, 0, 0, 0, path); NULL, 0, 0, 0);
space_remaining = space_remaining =
STREAM_CONCAT_REMAIN(s, snlri, STREAM_SIZE(s)) STREAM_CONCAT_REMAIN(s, snlri, STREAM_SIZE(s))
@ -1149,12 +1149,9 @@ void subgroup_default_update_packet(struct update_subgroup *subgrp,
/* Make place for total attribute length. */ /* Make place for total attribute length. */
pos = stream_get_endp(s); pos = stream_get_endp(s);
stream_putw(s, 0); stream_putw(s, 0);
total_attr_len = total_attr_len = bgp_packet_attribute(NULL, peer, s, attr, &vecarr, &p, afi, safi, from,
bgp_packet_attribute(NULL, peer, s, attr, &vecarr, &p, afi, NULL, &label, num_labels, addpath_capable,
safi, from, NULL, &label, num_labels, BGP_ADDPATH_TX_ID_FOR_DEFAULT_ORIGINATE);
addpath_capable,
BGP_ADDPATH_TX_ID_FOR_DEFAULT_ORIGINATE,
NULL);
/* Set Total Path Attribute Length. */ /* Set Total Path Attribute Length. */
stream_putw_at(s, pos, total_attr_len); stream_putw_at(s, pos, total_attr_len);