sctp: update mid instead of ssn when doing stream and asoc reset

When using idata and doing stream and asoc reset, setting ssn with
0 could only clear the 1st 16 bits of mid.

So to make this work for both data and idata, it sets mid with 0
instead of ssn, and also mid_uo for unordered idata also need to
be cleared, as said in section 2.3.2 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>

net/sctp/stream.c

@@ -216,11 +216,13 @@ void sctp_stream_clear(struct sctp_stream *stream)
 {
 	int i;
 
-	for (i = 0; i < stream->outcnt; i++)
-		stream->out[i].ssn = 0;
+	for (i = 0; i < stream->outcnt; i++) {
+		stream->out[i].mid = 0;
+		stream->out[i].mid_uo = 0;
+	}
 
 	for (i = 0; i < stream->incnt; i++)
-		stream->in[i].ssn = 0;
+		stream->in[i].mid = 0;
 }
 
 void sctp_stream_update(struct sctp_stream *stream, struct sctp_stream *new)
@@ -607,10 +609,10 @@ struct sctp_chunk *sctp_process_strreset_outreq(
 		}
 
 		for (i = 0; i < nums; i++)
-			stream->in[ntohs(str_p[i])].ssn = 0;
+			stream->in[ntohs(str_p[i])].mid = 0;
 	} else {
 		for (i = 0; i < stream->incnt; i++)
-			stream->in[i].ssn = 0;
+			stream->in[i].mid = 0;
 	}
 
 	result = SCTP_STRRESET_PERFORMED;
@@ -783,10 +785,12 @@ struct sctp_chunk *sctp_process_strreset_tsnreq(
 	/* G5:  The next expected and outgoing SSNs MUST be reset to 0 for all
 	 *      incoming and outgoing streams.
 	 */
-	for (i = 0; i < stream->outcnt; i++)
-		stream->out[i].ssn = 0;
+	for (i = 0; i < stream->outcnt; i++) {
+		stream->out[i].mid = 0;
+		stream->out[i].mid_uo = 0;
+	}
 	for (i = 0; i < stream->incnt; i++)
-		stream->in[i].ssn = 0;
+		stream->in[i].mid = 0;
 
 	result = SCTP_STRRESET_PERFORMED;
 
@@ -976,11 +980,15 @@ struct sctp_chunk *sctp_process_strreset_resp(
 
 		if (result == SCTP_STRRESET_PERFORMED) {
 			if (nums) {
-				for (i = 0; i < nums; i++)
-					stream->out[ntohs(str_p[i])].ssn = 0;
+				for (i = 0; i < nums; i++) {
+					stream->out[ntohs(str_p[i])].mid = 0;
+					stream->out[ntohs(str_p[i])].mid_uo = 0;
+				}
 			} else {
-				for (i = 0; i < stream->outcnt; i++)
-					stream->out[i].ssn = 0;
+				for (i = 0; i < stream->outcnt; i++) {
+					stream->out[i].mid = 0;
+					stream->out[i].mid_uo = 0;
+				}
 			}
 
 			flags = SCTP_STREAM_RESET_OUTGOING_SSN;
@@ -1041,10 +1049,12 @@ struct sctp_chunk *sctp_process_strreset_resp(
 			asoc->ctsn_ack_point = asoc->next_tsn - 1;
 			asoc->adv_peer_ack_point = asoc->ctsn_ack_point;
 
-			for (i = 0; i < stream->outcnt; i++)
-				stream->out[i].ssn = 0;
+			for (i = 0; i < stream->outcnt; i++) {
+				stream->out[i].mid = 0;
+				stream->out[i].mid_uo = 0;
+			}
 			for (i = 0; i < stream->incnt; i++)
-				stream->in[i].ssn = 0;
+				stream->in[i].mid = 0;
 		}
 
 		for (i = 0; i < stream->outcnt; i++)