[PATCH net v2 2/4] sctp: report the partially delivered MID in PARTIAL_DELIVERY_ABORTED

[Tim Budding]

When an I-FORWARD-TSN skips the message being partially delivered on a
stream, sctp_intl_skip() passes the MID from the I-FORWARD-TSN to the
PARTIAL_DELIVERY_ABORTED notification as pdapi_seq. That MID is the
highest one skipped on the stream, so when more than one message is
skipped, the notification names a later message instead of the one
whose partial delivery was aborted.

Report the MID being partially delivered, sin->mid_uo or sin->mid,
instead.

Reproduced on an unmodified kernel with the pdapi and pdapi_uo tests of
the sctp_ifwdtsn.sh selftest added later in this series, which pass
with this fix. Reproduction and fix done with AI assistance.

Fixes: de60fe910543 ("sctp: implement handle_ftsn for sctp_stream_interleave")
Reported-by: Sashiko <sashiko-bot@xxxxxxxxxx>
Closes: https://lore.kernel.org/all/179293012867.3134.16497481637722705271@xxxxxxxxxx/
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Tim Budding <tim.budding@xxxxxxxxx>
---
 net/sctp/stream_interleave.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/sctp/stream_interleave.c b/net/sctp/stream_interleave.c
index 869940001588..e239da686f68 100644
--- a/net/sctp/stream_interleave.c
+++ b/net/sctp/stream_interleave.c
@@ -1257,7 +1257,7 @@ static void sctp_intl_skip(struct sctp_ulpq *ulpq, __u16 sid, __u32 mid,
 	if (flags & SCTP_FTSN_U_BIT) {
 		if (sin->pd_mode_uo && !MID_lt(mid, sin->mid_uo)) {
 			sin->pd_mode_uo = 0;
-			sctp_intl_stream_abort_pd(ulpq, sid, mid, 0x1,
+			sctp_intl_stream_abort_pd(ulpq, sid, sin->mid_uo, 0x1,
 						  GFP_ATOMIC);
 		}
 		return;
@@ -1268,7 +1268,7 @@ static void sctp_intl_skip(struct sctp_ulpq *ulpq, __u16 sid, __u32 mid,
 
 	if (sin->pd_mode) {
 		sin->pd_mode = 0;
-		sctp_intl_stream_abort_pd(ulpq, sid, mid, 0x0, GFP_ATOMIC);
+		sctp_intl_stream_abort_pd(ulpq, sid, sin->mid, 0x0, GFP_ATOMIC);
 	}
 
 	sctp_mid_skip(stream, in, sid, mid);
-- 
2.34.1