bgpd: Optimize memory usage for attr struct

```
struct attr {
	struct aspath *            aspath;               /*     0     8 */
	struct community *         community;            /*     8     8 */
	long unsigned int          refcnt;               /*    16     8 */
	_uint64_t                  flag;                 /*    24     8 */
	struct in_addr             nexthop;              /*    32     4 */
	uint32_t                   med;                  /*    36     4 */
	uint32_t                   local_pref;           /*    40     4 */
	ifindex_t                  nh_ifindex;           /*    44     4 */
	uint8_t                    origin;               /*    48     1 */
	uint8_t                    es_flags;             /*    49     1 */
	uint8_t                    router_flag;          /*    50     1 */
	uint8_t                    default_gw;           /*    51     1 */
	enum pta_type              pmsi_tnl_type;        /*    52     4 */
	uint32_t                   rmap_change_flags;    /*    56     4 */
	struct in6_addr            mp_nexthop_global;    /*    60    16 */
	/* --- cacheline 1 boundary (64 bytes) was 12 bytes ago --- */
	struct in6_addr            mp_nexthop_local;     /*    76    16 */
	ifindex_t                  nh_lla_ifindex;       /*    92     4 */
	struct ecommunity *        ecommunity;           /*    96     8 */
	struct ecommunity *        ipv6_ecommunity;      /*   104     8 */
	struct lcommunity *        lcommunity;           /*   112     8 */
	struct cluster_list *      cluster1;             /*   120     8 */
	/* --- cacheline 2 boundary (128 bytes) --- */
	struct transit *           transit;              /*   128     8 */
	struct in_addr             mp_nexthop_global_in; /*   136     4 */
	struct in_addr             aggregator_addr;      /*   140     4 */
	struct in_addr             originator_id;        /*   144     4 */
	uint32_t                   weight;               /*   148     4 */
	as_t                       aggregator_as;        /*   152     4 */
	uint8_t                    mp_nexthop_len;       /*   156     1 */
	uint8_t                    mp_nexthop_prefer_global; /*   157     1 */
	uint8_t                    sticky;               /*   158     1 */
	uint8_t                    distance;             /*   159     1 */
	uint16_t                   encap_tunneltype;     /*   160     2 */
	uint8_t                    df_alg;               /*   162     1 */

	/* XXX 1 byte hole, try to pack */

	route_tag_t                tag;                  /*   164     4 */
	uint32_t                   label_index;          /*   168     4 */
	mpls_label_t               label;                /*   172     4 */
	struct bgp_attr_srv6_vpn * srv6_vpn;             /*   176     8 */
	struct bgp_attr_srv6_l3vpn * srv6_l3vpn;         /*   184     8 */
	/* --- cacheline 3 boundary (192 bytes) --- */
	struct bgp_attr_encap_subtlv * encap_subtlvs;    /*   192     8 */
	struct bgp_attr_encap_subtlv * vnc_subtlvs;      /*   200     8 */
	struct bgp_route_evpn      evpn_overlay;         /*   208    36 */
	uint32_t                   mm_seqnum;            /*   244     4 */
	uint32_t                   mm_sync_seqnum;       /*   248     4 */
	struct ethaddr             rmac;                 /*   252     6 */
	/* --- cacheline 4 boundary (256 bytes) was 2 bytes ago --- */
	uint16_t                   df_pref;              /*   258     2 */
	uint32_t                   rmap_table_id;        /*   260     4 */
	uint32_t                   link_bw;              /*   264     4 */
	esi_t                      esi;                  /*   268    10 */

	/* XXX 2 bytes hole, try to pack */

	uint32_t                   srte_color;           /*   280     4 */
	uint32_t                   otc;                  /*   284     4 */
	enum nexthop_types_t       nh_type;              /*   288     4 */
	enum blackhole_type        bh_type;              /*   292     4 */
	_uint64_t                  aigp_metric;          /*   296     8 */

	/* size: 304, cachelines: 5, members: 53 */
	/* sum members: 301, holes: 2, sum holes: 3 */
	/* last cacheline: 48 bytes */
};   /* saved 16 bytes! */
```

Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>

1 files changed, 44 insertions, 43 deletions

diff --git a/bgpd/bgp_attr.h b/bgpd/bgp_attr.h
index d30155e6db..9ac0c9854d 100644
--- a/bgpd/bgp_attr.h
+++ b/bgpd/bgp_attr.h
@@ -159,6 +159,45 @@ struct attr {
 	/* Path origin attribute */
 	uint8_t origin;
 
+	/* ES info */
+	uint8_t es_flags;
+	/* Path is not "locally-active" on the advertising VTEP. This is
+	 * translated into an ARP-ND ECOM.
+	 */
+#define ATTR_ES_PROXY_ADVERT (1 << 0)
+	/* Destination ES is present locally. This flag is set on local
+	 * paths and sync paths
+	 */
+#define ATTR_ES_IS_LOCAL (1 << 1)
+	/* There are one or more non-best paths from ES peers. Note that
+	 * this flag is only set on the local MAC-IP paths in the VNI
+	 * route table (not set in the global routing table). And only
+	 * non-proxy advertisements from an ES peer can result in this
+	 * flag being set.
+	 */
+#define ATTR_ES_PEER_ACTIVE (1 << 2)
+	/* There are one or more non-best proxy paths from ES peers */
+#define ATTR_ES_PEER_PROXY (1 << 3)
+	/* An ES peer has router bit set - only applicable if
+	 * ATTR_ES_PEER_ACTIVE is set
+	 */
+#define ATTR_ES_PEER_ROUTER (1 << 4)
+
+	/* These two flags are only set on L3 routes installed in a
+	 * VRF as a result of EVPN MAC-IP route
+	 * XXX - while splitting up per-family attrs these need to be
+	 * classified as non-EVPN
+	 */
+#define ATTR_ES_L3_NHG_USE    (1 << 5)
+#define ATTR_ES_L3_NHG_ACTIVE (1 << 6)
+#define ATTR_ES_L3_NHG	      (ATTR_ES_L3_NHG_USE | ATTR_ES_L3_NHG_ACTIVE)
+
+	/* NA router flag (R-bit) support in EVPN */
+	uint8_t router_flag;
+
+	/* Distance as applied by Route map */
+	uint8_t distance;
+
 	/* PMSI tunnel type (RFC 6514). */
 	enum pta_type pmsi_tnl_type;
 
@@ -214,42 +253,6 @@ struct attr {
 	/* Flag for default gateway extended community in EVPN */
 	uint8_t default_gw;
 
-	/* NA router flag (R-bit) support in EVPN */
-	uint8_t router_flag;
-
-	/* ES info */
-	uint8_t es_flags;
-	/* Path is not "locally-active" on the advertising VTEP. This is
-	 * translated into an ARP-ND ECOM.
-	 */
-#define ATTR_ES_PROXY_ADVERT (1 << 0)
-	/* Destination ES is present locally. This flag is set on local
-	 * paths and sync paths
-	 */
-#define ATTR_ES_IS_LOCAL (1 << 1)
-	/* There are one or more non-best paths from ES peers. Note that
-	 * this flag is only set on the local MAC-IP paths in the VNI
-	 * route table (not set in the global routing table). And only
-	 * non-proxy advertisements from an ES peer can result in this
-	 * flag being set.
-	 */
-#define ATTR_ES_PEER_ACTIVE (1 << 2)
-	/* There are one or more non-best proxy paths from ES peers */
-#define ATTR_ES_PEER_PROXY (1 << 3)
-	/* An ES peer has router bit set - only applicable if
-	 * ATTR_ES_PEER_ACTIVE is set
-	 */
-#define ATTR_ES_PEER_ROUTER (1 << 4)
-
-	/* These two flags are only set on L3 routes installed in a
-	 * VRF as a result of EVPN MAC-IP route
-	 * XXX - while splitting up per-family attrs these need to be
-	 * classified as non-EVPN
-	 */
-#define ATTR_ES_L3_NHG_USE (1 << 5)
-#define ATTR_ES_L3_NHG_ACTIVE (1 << 6)
-#define ATTR_ES_L3_NHG (ATTR_ES_L3_NHG_USE | ATTR_ES_L3_NHG_ACTIVE)
-
 	/* route tag */
 	route_tag_t tag;
 
@@ -259,13 +262,16 @@ struct attr {
 	/* MPLS label */
 	mpls_label_t label;
 
+	/* EVPN DF preference for DF election on local ESs */
+	uint16_t df_pref;
+	uint8_t df_alg;
+
 	/* SRv6 VPN SID */
 	struct bgp_attr_srv6_vpn *srv6_vpn;
 
 	/* SRv6 L3VPN SID */
 	struct bgp_attr_srv6_l3vpn *srv6_l3vpn;
 
-	uint16_t encap_tunneltype;		     /* grr */
 	struct bgp_attr_encap_subtlv *encap_subtlvs; /* rfc5512 */
 
 #ifdef ENABLE_BGP_VNC
@@ -287,8 +293,7 @@ struct attr {
 	/* EVPN local router-mac */
 	struct ethaddr rmac;
 
-	/* Distance as applied by Route map */
-	uint8_t distance;
+	uint16_t encap_tunneltype;
 
 	/* rmap set table */
 	uint32_t rmap_table_id;
@@ -302,10 +307,6 @@ struct attr {
 	/* SR-TE Color */
 	uint32_t srte_color;
 
-	/* EVPN DF preference and algorithm for DF election on local ESs */
-	uint16_t df_pref;
-	uint8_t df_alg;
-
 	/* Nexthop type */
 	enum nexthop_types_t nh_type;