From d901dc13cb566fb3b76c5b6a9427d9c699494c49 Mon Sep 17 00:00:00 2001
From: vivek <vivek@cumulusnetworks.com>
Date: Tue, 24 Mar 2020 12:17:19 -0700
Subject: [PATCH] bgpd: Check and extract link bandwidth value

Extract link bandwidth value into attribute from the extended
community, if present.

Signed-off-by: Vivek Venkatraman <vivek@cumulusnetworks.com>
---
 bgpd/bgp_attr.c       |  3 +++
 bgpd/bgp_attr.h       |  4 +++-
 bgpd/bgp_ecommunity.c | 39 +++++++++++++++++++++++++++++++++++++++
 bgpd/bgp_ecommunity.h |  3 ++-
 4 files changed, 47 insertions(+), 2 deletions(-)

diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c
index 221386e38d..d6eb6beddb 100644
--- a/bgpd/bgp_attr.c
+++ b/bgpd/bgp_attr.c
@@ -2246,6 +2246,9 @@ bgp_attr_ext_communities(struct bgp_attr_parser_args *args)
 	bgp_attr_extcom_tunnel_type(attr,
 		(bgp_encap_types *)&attr->encap_tunneltype);
 
+	/* Extract link bandwidth, if any. */
+	(void)ecommunity_linkbw_present(attr->ecommunity, &attr->link_bw);
+
 	return BGP_ATTR_PARSE_PROCEED;
 }
 
diff --git a/bgpd/bgp_attr.h b/bgpd/bgp_attr.h
index 98a9a620f7..5fec4be29c 100644
--- a/bgpd/bgp_attr.h
+++ b/bgpd/bgp_attr.h
@@ -250,6 +250,9 @@ struct attr {
 
 	/* rmap set table */
 	uint32_t rmap_table_id;
+
+	/* Link bandwidth value, if any. */
+	uint32_t link_bw;
 };
 
 /* rmap_change_flags definition */
@@ -409,5 +412,4 @@ static inline uint32_t mac_mobility_seqnum(struct attr *attr)
 {
 	return (attr) ? attr->mm_seqnum : 0;
 }
-
 #endif /* _QUAGGA_BGP_ATTR_H */
diff --git a/bgpd/bgp_ecommunity.c b/bgpd/bgp_ecommunity.c
index 5e5a32d420..dd97a3d213 100644
--- a/bgpd/bgp_ecommunity.c
+++ b/bgpd/bgp_ecommunity.c
@@ -1203,3 +1203,42 @@ void bgp_remove_ecomm_from_aggregate_hash(struct bgp_aggregate *aggregate,
 		}
 	}
 }
+
+/*
+ * return the BGP link bandwidth extended community, if present;
+ * the actual bandwidth is returned via param
+ */
+const uint8_t *ecommunity_linkbw_present(struct ecommunity *ecom, uint32_t *bw)
+{
+	const uint8_t *eval;
+	int i;
+
+	if (bw)
+		*bw = 0;
+
+	if (!ecom || !ecom->size)
+		return NULL;
+
+	for (i = 0; i < ecom->size; i++) {
+		const uint8_t *pnt;
+		uint8_t type, sub_type;
+		uint32_t bwval;
+
+		eval = pnt = (ecom->val + (i * ECOMMUNITY_SIZE));
+		type = *pnt++;
+		sub_type = *pnt++;
+
+		if ((type == ECOMMUNITY_ENCODE_AS ||
+		     type == ECOMMUNITY_ENCODE_AS_NON_TRANS) &&
+		    sub_type == ECOMMUNITY_LINK_BANDWIDTH) {
+			pnt += 2; /* bandwidth is encoded as AS:val */
+			pnt = ptr_get_be32(pnt, &bwval);
+			(void)pnt; /* consume value */
+			if (bw)
+				*bw = bwval;
+			return eval;
+		}
+	}
+
+	return NULL;
+}
diff --git a/bgpd/bgp_ecommunity.h b/bgpd/bgp_ecommunity.h
index b61deba922..3aeafb75ea 100644
--- a/bgpd/bgp_ecommunity.h
+++ b/bgpd/bgp_ecommunity.h
@@ -236,7 +236,8 @@ extern void bgp_remove_ecomm_from_aggregate_hash(
 					struct bgp_aggregate *aggregate,
 					struct ecommunity *ecommunity);
 extern void bgp_aggr_ecommunity_remove(void *arg);
-
+extern const uint8_t *ecommunity_linkbw_present(struct ecommunity *ecom,
+						uint32_t *bw);
 
 static inline void ecommunity_strip_rts(struct ecommunity *ecom)
 {
-- 
2.39.5