sctp: implement assign_number for sctp_stream_interleave

assign_number is added as a member of sctp_stream_interleave, used
to assign ssn for data or mid (message id) for idata, called in
sctp_packet_append_data. sctp_chunk_assign_ssn is left as it is,
and sctp_chunk_assign_mid is added for sctp_stream_interleave_1.

This procedure is described in section 2.2.2 of RFC8260.

All sizeof(struct sctp_data_chunk) in tx path is replaced with
sctp_datachk_len, to make it right for idata as well. And also
adjust sctp_chunk_is_data for SCTP_CID_I_DATA.

After this patch, idata can be built and sent in tx path.

Note that if sp strm_interleave is set, it has to wait_connect in
sctp_sendmsg, as asoc intl_enable need to be known after 4 shake-
hands, to decide if it should use data or idata later. data and
idata can't be mixed to send in one asoc.

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

1 files changed, 37 insertions, 0 deletions

diff --git a/net/sctp/stream_interleave.c b/net/sctp/stream_interleave.c
index 397c3c1789b3..3ac47e78c013 100644
--- a/net/sctp/stream_interleave.c
+++ b/net/sctp/stream_interleave.c
@@ -57,16 +57,53 @@ static struct sctp_chunk *sctp_make_idatafrag_empty(
 	return retval;
 }
 
+static void sctp_chunk_assign_mid(struct sctp_chunk *chunk)
+{
+	struct sctp_stream *stream;
+	struct sctp_chunk *lchunk;
+	__u32 cfsn = 0;
+	__u16 sid;
+
+	if (chunk->has_mid)
+		return;
+
+	sid = sctp_chunk_stream_no(chunk);
+	stream = &chunk->asoc->stream;
+
+	list_for_each_entry(lchunk, &chunk->msg->chunks, frag_list) {
+		struct sctp_idatahdr *hdr;
+
+		lchunk->has_mid = 1;
+
+		if (lchunk->chunk_hdr->flags & SCTP_DATA_UNORDERED)
+			continue;
+
+		hdr = lchunk->subh.idata_hdr;
+
+		if (lchunk->chunk_hdr->flags & SCTP_DATA_FIRST_FRAG)
+			hdr->ppid = lchunk->sinfo.sinfo_ppid;
+		else
+			hdr->fsn = htonl(cfsn++);
+
+		if (lchunk->chunk_hdr->flags & SCTP_DATA_LAST_FRAG)
+			hdr->mid = htonl(sctp_mid_next(stream, out, sid));
+		else
+			hdr->mid = htonl(sctp_mid_peek(stream, out, sid));
+	}
+}
+
 static struct sctp_stream_interleave sctp_stream_interleave_0 = {
 	.data_chunk_len		= sizeof(struct sctp_data_chunk),
 	/* DATA process functions */
 	.make_datafrag		= sctp_make_datafrag_empty,
+	.assign_number		= sctp_chunk_assign_ssn,
 };
 
 static struct sctp_stream_interleave sctp_stream_interleave_1 = {
 	.data_chunk_len		= sizeof(struct sctp_idata_chunk),
 	/* I-DATA process functions */
 	.make_datafrag		= sctp_make_idatafrag_empty,
+	.assign_number		= sctp_chunk_assign_mid,
 };
 
 void sctp_stream_interleave_init(struct sctp_stream *stream)