From d56c0d23b0c5b60e2ae9f2ae1af9c143b49a4539 Mon Sep 17 00:00:00 2001
From: Carmine Scarpitta <carmine.scarpitta@uniroma2.it>
Date: Thu, 25 May 2023 15:21:50 +0200
Subject: [PATCH] isisd: Unpack SRv6 (LAN) End.X SID Sub-TLV

Extend the Extended IS Reachability TLV unpack function to unpack the
SRv6 End.X SID Sub-TLV and SRv6 LAN End.X SID Sub-TLV, if present.

Signed-off-by: Carmine Scarpitta <carmine.scarpitta@uniroma2.it>
---
 isisd/isis_tlvs.c | 97 +++++++++++++++++++++++++++++++++++++++++++++++
 isisd/isis_tlvs.h |  2 +
 2 files changed, 99 insertions(+)

diff --git a/isisd/isis_tlvs.c b/isisd/isis_tlvs.c
index f164453849..918bb9b9d9 100644
--- a/isisd/isis_tlvs.c
+++ b/isisd/isis_tlvs.c
@@ -120,6 +120,10 @@ static void isis_format_subsubtlvs(struct isis_subsubtlvs *subsubtlvs,
 				   int indent);
 static int isis_pack_subsubtlvs(struct isis_subsubtlvs *subsubtlvs,
 				struct stream *s);
+static int unpack_tlvs(enum isis_tlv_context context, size_t avail_len,
+		       struct stream *stream, struct sbuf *log, void *dest,
+		       int indent, bool *unpacked_known_tlvs);
+static void isis_free_subsubtlvs(struct isis_subsubtlvs *subsubtlvs);
 
 /* For tests/isisd, TLV text requires ipv4-unicast instead of standard */
 static const char *isis_mtid2str_fake(uint16_t mtid)
@@ -1656,6 +1660,7 @@ static int unpack_item_ext_subtlvs(uint16_t mtid, uint8_t len, struct stream *s,
 	uint8_t sum = 0;
 	uint8_t subtlv_type;
 	uint8_t subtlv_len;
+	uint8_t subsubtlv_len;
 	size_t nb_groups;
 	uint32_t val;
 
@@ -1994,6 +1999,92 @@ static int unpack_item_ext_subtlvs(uint16_t mtid, uint8_t len, struct stream *s,
 				SET_SUBTLV(exts, EXT_LAN_ADJ_SID);
 			}
 			break;
+		/* SRv6 End.X SID as per RFC9352 section #8.1 */
+		case ISIS_SUBTLV_SRV6_ENDX_SID:
+			if (subtlv_len < ISIS_SUBTLV_SRV6_ENDX_SID_SIZE) {
+				TLV_SIZE_MISMATCH(log, indent,
+						  "SRv6 End.X SID");
+				stream_forward_getp(s, subtlv_len);
+			} else {
+				struct isis_srv6_endx_sid_subtlv *adj;
+
+				adj = XCALLOC(
+					MTYPE_ISIS_SUBTLV,
+					sizeof(struct
+					       isis_srv6_endx_sid_subtlv));
+				adj->flags = stream_getc(s);
+				adj->algorithm = stream_getc(s);
+				adj->weight = stream_getc(s);
+				adj->behavior = stream_getw(s);
+				stream_get(&adj->sid, s, IPV6_MAX_BYTELEN);
+				subsubtlv_len = stream_getc(s);
+
+				adj->subsubtlvs = isis_alloc_subsubtlvs(
+					ISIS_CONTEXT_SUBSUBTLV_SRV6_ENDX_SID);
+
+				bool unpacked_known_tlvs = false;
+				if (unpack_tlvs(
+					    ISIS_CONTEXT_SUBSUBTLV_SRV6_ENDX_SID,
+					    subsubtlv_len, s, log,
+					    adj->subsubtlvs, indent + 4,
+					    &unpacked_known_tlvs)) {
+					XFREE(MTYPE_ISIS_SUBTLV, adj);
+					break;
+				}
+				if (!unpacked_known_tlvs) {
+					isis_free_subsubtlvs(adj->subsubtlvs);
+					adj->subsubtlvs = NULL;
+				}
+
+				append_item(&exts->srv6_endx_sid,
+					    (struct isis_item *)adj);
+				SET_SUBTLV(exts, EXT_SRV6_ENDX_SID);
+			}
+			break;
+		/* SRv6 LAN End.X SID as per RFC9352 section #8.2 */
+		case ISIS_SUBTLV_SRV6_LAN_ENDX_SID:
+			if (subtlv_len < ISIS_SUBTLV_SRV6_LAN_ENDX_SID_SIZE) {
+				TLV_SIZE_MISMATCH(log, indent,
+						  "SRv6 LAN End.X SID");
+				stream_forward_getp(s, subtlv_len);
+			} else {
+				struct isis_srv6_lan_endx_sid_subtlv *lan;
+
+				lan = XCALLOC(
+					MTYPE_ISIS_SUBTLV,
+					sizeof(struct
+					       isis_srv6_lan_endx_sid_subtlv));
+				stream_get(&(lan->neighbor_id), s,
+					   ISIS_SYS_ID_LEN);
+				lan->flags = stream_getc(s);
+				lan->algorithm = stream_getc(s);
+				lan->weight = stream_getc(s);
+				lan->behavior = stream_getw(s);
+				stream_get(&lan->sid, s, IPV6_MAX_BYTELEN);
+				subsubtlv_len = stream_getc(s);
+
+				lan->subsubtlvs = isis_alloc_subsubtlvs(
+					ISIS_CONTEXT_SUBSUBTLV_SRV6_ENDX_SID);
+
+				bool unpacked_known_tlvs = false;
+				if (unpack_tlvs(
+					    ISIS_CONTEXT_SUBSUBTLV_SRV6_ENDX_SID,
+					    subsubtlv_len, s, log,
+					    lan->subsubtlvs, indent + 4,
+					    &unpacked_known_tlvs)) {
+					XFREE(MTYPE_ISIS_SUBTLV, lan);
+					break;
+				}
+				if (!unpacked_known_tlvs) {
+					isis_free_subsubtlvs(lan->subsubtlvs);
+					lan->subsubtlvs = NULL;
+				}
+
+				append_item(&exts->srv6_lan_endx_sid,
+					    (struct isis_item *)lan);
+				SET_SUBTLV(exts, EXT_SRV6_LAN_ENDX_SID);
+			}
+			break;
 		case ISIS_SUBTLV_ASLA:
 			if (unpack_item_ext_subtlv_asla(mtid, subtlv_len, s,
 							log, indent,
@@ -7147,6 +7238,12 @@ static const struct tlv_ops *const tlv_table[ISIS_CONTEXT_MAX][ISIS_TLV_MAX] = {
 	},
 	[ISIS_CONTEXT_SUBSUBTLV_SRV6_END_SID] = {
 		[ISIS_SUBSUBTLV_SRV6_SID_STRUCTURE] = &subsubtlv_srv6_sid_structure_ops,
+	},
+	[ISIS_CONTEXT_SUBSUBTLV_SRV6_ENDX_SID] = {
+		[ISIS_SUBSUBTLV_SRV6_SID_STRUCTURE] = &subsubtlv_srv6_sid_structure_ops,
+	},
+	[ISIS_CONTEXT_SUBSUBTLV_SRV6_LAN_ENDX_SID] = {
+		[ISIS_SUBSUBTLV_SRV6_SID_STRUCTURE] = &subsubtlv_srv6_sid_structure_ops,
 	}
 };
 
diff --git a/isisd/isis_tlvs.h b/isisd/isis_tlvs.h
index 38072719f4..825610ed35 100644
--- a/isisd/isis_tlvs.h
+++ b/isisd/isis_tlvs.h
@@ -423,6 +423,8 @@ enum isis_tlv_context {
 	ISIS_CONTEXT_SUBTLV_IPV6_REACH,
 	ISIS_CONTEXT_SUBTLV_SRV6_LOCATOR,
 	ISIS_CONTEXT_SUBSUBTLV_SRV6_END_SID,
+	ISIS_CONTEXT_SUBSUBTLV_SRV6_ENDX_SID,
+	ISIS_CONTEXT_SUBSUBTLV_SRV6_LAN_ENDX_SID,
 	ISIS_CONTEXT_MAX,
 };