sctp: add SCTP_SEND_FAILED_EVENT event

This patch is to add a new event SCTP_SEND_FAILED_EVENT described in
rfc6458#section-6.1.11. It's a update of SCTP_SEND_FAILED event:

  struct sctp_sndrcvinfo ssf_info is replaced with
  struct sctp_sndinfo ssfe_info in struct sctp_send_failed_event.

SCTP_SEND_FAILED is being deprecated, but we don't remove it in this
patch. Both are being processed in sctp_datamsg_destroy() when the
corresp event flag is set.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>

include/net/sctp/ulpevent.h

@@ -95,6 +95,13 @@ struct sctp_ulpevent *sctp_ulpevent_make_send_failed(
 	__u32 error,
 	gfp_t gfp);
 
+struct sctp_ulpevent *sctp_ulpevent_make_send_failed_event(
+	const struct sctp_association *asoc,
+	struct sctp_chunk *chunk,
+	__u16 flags,
+	__u32 error,
+	gfp_t gfp);
+
 struct sctp_ulpevent *sctp_ulpevent_make_shutdown_event(
 	const struct sctp_association *asoc,
 	__u16 flags,

include/uapi/linux/sctp.h

@@ -449,6 +449,16 @@ struct sctp_send_failed {
 	__u8 ssf_data[0];
 };
 
+struct sctp_send_failed_event {
+	__u16 ssf_type;
+	__u16 ssf_flags;
+	__u32 ssf_length;
+	__u32 ssf_error;
+	struct sctp_sndinfo ssfe_info;
+	sctp_assoc_t ssf_assoc_id;
+	__u8 ssf_data[0];
+};
+
 /*
  *   ssf_flags: 16 bits (unsigned integer)
  *
@@ -605,6 +615,7 @@ struct sctp_event_subscribe {
 	__u8 sctp_stream_reset_event;
 	__u8 sctp_assoc_reset_event;
 	__u8 sctp_stream_change_event;
+	__u8 sctp_send_failure_event_event;
 };
 
 /*
@@ -632,6 +643,7 @@ union sctp_notification {
 	struct sctp_stream_reset_event sn_strreset_event;
 	struct sctp_assoc_reset_event sn_assocreset_event;
 	struct sctp_stream_change_event sn_strchange_event;
+	struct sctp_send_failed_event sn_send_failed_event;
 };
 
 /* Section 5.3.1
@@ -667,7 +679,9 @@ enum sctp_sn_type {
 #define SCTP_ASSOC_RESET_EVENT		SCTP_ASSOC_RESET_EVENT
 	SCTP_STREAM_CHANGE_EVENT,
 #define SCTP_STREAM_CHANGE_EVENT	SCTP_STREAM_CHANGE_EVENT
-	SCTP_SN_TYPE_MAX	= SCTP_STREAM_CHANGE_EVENT,
+	SCTP_SEND_FAILED_EVENT,
+#define SCTP_SEND_FAILED_EVENT		SCTP_SEND_FAILED_EVENT
+	SCTP_SN_TYPE_MAX	= SCTP_SEND_FAILED_EVENT,
 #define SCTP_SN_TYPE_MAX		SCTP_SN_TYPE_MAX
 };
 

net/sctp/chunk.c

@@ -75,41 +75,39 @@ static void sctp_datamsg_destroy(struct sctp_datamsg *msg)
 	struct list_head *pos, *temp;
 	struct sctp_chunk *chunk;
 	struct sctp_ulpevent *ev;
-	int error = 0, notify;
-
-	/* If we failed, we may need to notify. */
-	notify = msg->send_failed ? -1 : 0;
+	int error, sent;
 
 	/* Release all references. */
 	list_for_each_safe(pos, temp, &msg->chunks) {
 		list_del_init(pos);
 		chunk = list_entry(pos, struct sctp_chunk, frag_list);
-		/* Check whether we _really_ need to notify. */
-		if (notify < 0) {
-			asoc = chunk->asoc;
-			if (msg->send_error)
-				error = msg->send_error;
-			else
-				error = asoc->outqueue.error;
-
-			notify = sctp_ulpevent_type_enabled(asoc->subscribe,
-							    SCTP_SEND_FAILED);
+
+		if (!msg->send_failed) {
+			sctp_chunk_put(chunk);
+			continue;
 		}
 
-		/* Generate a SEND FAILED event only if enabled. */
-		if (notify > 0) {
-			int sent;
-			if (chunk->has_tsn)
-				sent = SCTP_DATA_SENT;
-			else
-				sent = SCTP_DATA_UNSENT;
+		asoc = chunk->asoc;
+		error = msg->send_error ?: asoc->outqueue.error;
+		sent = chunk->has_tsn ? SCTP_DATA_SENT : SCTP_DATA_UNSENT;
 
+		if (sctp_ulpevent_type_enabled(asoc->subscribe,
+					       SCTP_SEND_FAILED)) {
 			ev = sctp_ulpevent_make_send_failed(asoc, chunk, sent,
 							    error, GFP_ATOMIC);
 			if (ev)
 				asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
 		}
 
+		if (sctp_ulpevent_type_enabled(asoc->subscribe,
+					       SCTP_SEND_FAILED_EVENT)) {
+			ev = sctp_ulpevent_make_send_failed_event(asoc, chunk,
+								  sent, error,
+								  GFP_ATOMIC);
+			if (ev)
+				asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
+		}
+
 		sctp_chunk_put(chunk);
 	}
 

net/sctp/ulpevent.c

@@ -527,6 +527,45 @@ struct sctp_ulpevent *sctp_ulpevent_make_send_failed(
 	return NULL;
 }
 
+struct sctp_ulpevent *sctp_ulpevent_make_send_failed_event(
+	const struct sctp_association *asoc, struct sctp_chunk *chunk,
+	__u16 flags, __u32 error, gfp_t gfp)
+{
+	struct sctp_send_failed_event *ssf;
+	struct sctp_ulpevent *event;
+	struct sk_buff *skb;
+	int len;
+
+	skb = skb_copy_expand(chunk->skb, sizeof(*ssf), 0, gfp);
+	if (!skb)
+		return NULL;
+
+	len = ntohs(chunk->chunk_hdr->length);
+	len -= sctp_datachk_len(&asoc->stream);
+
+	skb_pull(skb, sctp_datachk_len(&asoc->stream));
+	event = sctp_skb2event(skb);
+	sctp_ulpevent_init(event, MSG_NOTIFICATION, skb->truesize);
+
+	ssf = skb_push(skb, sizeof(*ssf));
+	ssf->ssf_type = SCTP_SEND_FAILED_EVENT;
+	ssf->ssf_flags = flags;
+	ssf->ssf_length = sizeof(*ssf) + len;
+	skb_trim(skb, ssf->ssf_length);
+	ssf->ssf_error = error;
+
+	ssf->ssfe_info.snd_sid = chunk->sinfo.sinfo_stream;
+	ssf->ssfe_info.snd_ppid = chunk->sinfo.sinfo_ppid;
+	ssf->ssfe_info.snd_context = chunk->sinfo.sinfo_context;
+	ssf->ssfe_info.snd_assoc_id = chunk->sinfo.sinfo_assoc_id;
+	ssf->ssfe_info.snd_flags = chunk->chunk_hdr->flags;
+
+	sctp_ulpevent_set_owner(event, asoc);
+	ssf->ssf_assoc_id = sctp_assoc2id(asoc);
+
+	return event;
+}
+
 /* Create and initialize a SCTP_SHUTDOWN_EVENT notification.
  *
  * Socket Extensions for SCTP - draft-01