From 921c7e77b0e19f360f0ed74b834d065fce84acf0 Mon Sep 17 00:00:00 2001
From: Ryoga Saito <ryoga.saito@linecorp.com>
Date: Fri, 25 Feb 2022 13:40:28 +0000
Subject: [PATCH] bgpd: update logic to allocate SRv6 locator

For the later patches, this patch changes the behavior of alloc_new sid
so that bgpd record not only SID for VRF, but also Locator of SID.

Signed-off-by: Ryoga Saito <ryoga.saito@linecorp.com>
---
 bgpd/bgp_mplsvpn.c | 25 +++++++++++++++++--------
 bgpd/bgpd.h        |  1 +
 2 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/bgpd/bgp_mplsvpn.c b/bgpd/bgp_mplsvpn.c
index eafc37f20c..1ca191012f 100644
--- a/bgpd/bgp_mplsvpn.c
+++ b/bgpd/bgp_mplsvpn.c
@@ -520,7 +520,7 @@ static bool sid_exist(struct bgp *bgp, const struct in6_addr *sid)
  * else: try to allocate as auto-mode
  */
 static uint32_t alloc_new_sid(struct bgp *bgp, uint32_t index,
-			      struct in6_addr *sid)
+			      struct in6_addr *sid_locator)
 {
 	struct listnode *node;
 	struct prefix_ipv6 *chunk;
@@ -528,10 +528,11 @@ static uint32_t alloc_new_sid(struct bgp *bgp, uint32_t index,
 	bool alloced = false;
 	int label = 0;
 
-	if (!bgp || !sid)
+	if (!bgp || !sid_locator)
 		return false;
 
 	for (ALL_LIST_ELEMENTS_RO(bgp->srv6_locator_chunks, node, chunk)) {
+		*sid_locator = chunk->prefix;
 		sid_buf = chunk->prefix;
 		if (index != 0) {
 			label = index << 12;
@@ -556,7 +557,6 @@ static uint32_t alloc_new_sid(struct bgp *bgp, uint32_t index,
 		return 0;
 
 	sid_register(bgp, &sid_buf, bgp->srv6_locator_name);
-	*sid = sid_buf;
 	return label;
 }
 
@@ -564,7 +564,7 @@ void ensure_vrf_tovpn_sid(struct bgp *bgp_vpn, struct bgp *bgp_vrf, afi_t afi)
 {
 	int debug = BGP_DEBUG(vpn, VPN_LEAK_FROM_VRF);
 	char buf[256];
-	struct in6_addr *sid;
+	struct in6_addr *tovpn_sid, *tovpn_sid_locator;
 	uint32_t tovpn_sid_index = 0, tovpn_sid_transpose_label;
 	bool tovpn_sid_auto = false;
 
@@ -598,24 +598,33 @@ void ensure_vrf_tovpn_sid(struct bgp *bgp_vpn, struct bgp *bgp_vrf, afi_t afi)
 		return;
 	}
 
-	sid = XCALLOC(MTYPE_BGP_SRV6_SID, sizeof(struct in6_addr));
+	tovpn_sid_locator =
+		XCALLOC(MTYPE_BGP_SRV6_SID, sizeof(struct in6_addr));
 	tovpn_sid_transpose_label =
-		alloc_new_sid(bgp_vpn, tovpn_sid_index, sid);
+		alloc_new_sid(bgp_vpn, tovpn_sid_index, tovpn_sid_locator);
 	if (tovpn_sid_transpose_label == 0) {
 		zlog_debug("%s: not allocated new sid for vrf %s: afi %s",
 			   __func__, bgp_vrf->name_pretty, afi2str(afi));
 		return;
 	}
 
+	tovpn_sid = XCALLOC(MTYPE_BGP_SRV6_SID, sizeof(struct in6_addr));
+	*tovpn_sid = *tovpn_sid_locator;
+	transpose_sid(tovpn_sid, tovpn_sid_transpose_label,
+		      BGP_PREFIX_SID_SRV6_TRANSPOSITION_OFFSET,
+		      BGP_PREFIX_SID_SRV6_TRANSPOSITION_LENGTH);
+
 	if (debug) {
-		inet_ntop(AF_INET6, sid, buf, sizeof(buf));
+		inet_ntop(AF_INET6, tovpn_sid, buf, sizeof(buf));
 		zlog_debug("%s: new sid %s allocated for vrf %s: afi %s",
 			   __func__, buf, bgp_vrf->name_pretty,
 			   afi2str(afi));
 	}
+
+	bgp_vrf->vpn_policy[afi].tovpn_sid = tovpn_sid;
+	bgp_vrf->vpn_policy[afi].tovpn_sid_locator = tovpn_sid_locator;
 	bgp_vrf->vpn_policy[afi].tovpn_sid_transpose_label =
 		tovpn_sid_transpose_label;
-	bgp_vrf->vpn_policy[afi].tovpn_sid = sid;
 }
 
 void transpose_sid(struct in6_addr *sid, uint32_t label, uint8_t offset,
diff --git a/bgpd/bgpd.h b/bgpd/bgpd.h
index 926b0b033f..a9475f39a7 100644
--- a/bgpd/bgpd.h
+++ b/bgpd/bgpd.h
@@ -234,6 +234,7 @@ struct vpn_policy {
 	 */
 	uint32_t tovpn_sid_index; /* unset => set to 0 */
 	struct in6_addr *tovpn_sid;
+	struct in6_addr *tovpn_sid_locator;
 	uint32_t tovpn_sid_transpose_label;
 	struct in6_addr *tovpn_zebra_vrf_sid_last_sent;
 };
-- 
2.39.5