sctp: add basic structures and make chunk function for ifwdtsn

sctp_ifwdtsn_skip, sctp_ifwdtsn_hdr and sctp_ifwdtsn_chunk are used to
define and parse I-FWD TSN chunk format, and sctp_make_ifwdtsn is a
function to build the chunk.

The I-FORWARD-TSN Chunk Format is defined in section 2.3.1 of RFC8260.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo R. Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 17 insertions, 0 deletions

diff --git a/include/linux/sctp.h b/include/linux/sctp.h
index 38e2cf66195f..b36c76635f18 100644
--- a/include/linux/sctp.h
+++ b/include/linux/sctp.h
@@ -110,6 +110,7 @@ enum sctp_cid {
 
         /* Use hex, as defined in ADDIP sec. 3.1 */
         SCTP_CID_ASCONF                 = 0xC1,
+        SCTP_CID_I_FWD_TSN              = 0xC2,
         SCTP_CID_ASCONF_ACK             = 0x80,
         SCTP_CID_RECONF                 = 0x82,
 }; /* enum */
@@ -616,6 +617,22 @@ struct sctp_fwdtsn_chunk {
         struct sctp_fwdtsn_hdr fwdtsn_hdr;
 };
 
+struct sctp_ifwdtsn_skip {
+        __be16 stream;
+        __u8 reserved;
+        __u8 flags;
+        __be32 mid;
+};
+
+struct sctp_ifwdtsn_hdr {
+        __be32 new_cum_tsn;
+        struct sctp_ifwdtsn_skip skip[0];
+};
+
+struct sctp_ifwdtsn_chunk {
+        struct sctp_chunkhdr chunk_hdr;
+        struct sctp_ifwdtsn_hdr fwdtsn_hdr;
+};
 
 /* ADDIP
  * Section 3.1.1 Address Configuration Change Chunk (ASCONF)