[PATCH net 1/4] can: j1939: fix support for multipacket broadcast message

[Zhang Changzhong]

Currently j1939_tp_im_involved_anydir() in j1939_tp_recv() check the
previously set flags J1939_ECU_LOCAL_DST and J1939_ECU_LOCAL_SRC of
incoming skb, thus multipacket broadcast message was aborted by
receive side because it may come from remote ECUs and have no exact
dst address. Similarly, j1939_tp_cmd_recv() and j1939_xtp_rx_dat()
didn't process broadcast message.

So fix it by checking and process broadcast message in j1939_tp_recv(),
j1939_tp_cmd_recv() and j1939_xtp_rx_dat().

Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol")
Signed-off-by: Zhang Changzhong <zhangchangzhong@xxxxxxxxxx>
---
 net/can/j1939/transport.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/net/can/j1939/transport.c b/net/can/j1939/transport.c
index 9f99af5..e5188ac 100644
--- a/net/can/j1939/transport.c
+++ b/net/can/j1939/transport.c
@@ -1651,8 +1651,12 @@ static void j1939_xtp_rx_rts(struct j1939_priv *priv, struct sk_buff *skb,
 			return;
 		}
 		session = j1939_xtp_rx_rts_session_new(priv, skb);
-		if (!session)
+		if (!session) {
+			if (cmd == J1939_TP_CMD_BAM && j1939_sk_recv_match(priv, skcb))
+				netdev_info(priv->ndev, "%s: failed to create TP BAM session\n",
+					    __func__);
 			return;
+		}
 	} else {
 		if (j1939_xtp_rx_rts_session_active(session, skb)) {
 			j1939_session_put(session);
@@ -1829,6 +1833,13 @@ static void j1939_xtp_rx_dat(struct j1939_priv *priv, struct sk_buff *skb)
 		else
 			j1939_xtp_rx_dat_one(session, skb);
 	}
+
+	if (j1939_cb_is_broadcast(skcb)) {
+		session = j1939_session_get_by_addr(priv, &skcb->addr, false,
+						    false);
+		if (session)
+			j1939_xtp_rx_dat_one(session, skb);
+	}
 }
 
 /* j1939 main intf */
@@ -1920,7 +1931,7 @@ static void j1939_tp_cmd_recv(struct j1939_priv *priv, struct sk_buff *skb)
 		if (j1939_tp_im_transmitter(skcb))
 			j1939_xtp_rx_rts(priv, skb, true);
 
-		if (j1939_tp_im_receiver(skcb))
+		if (j1939_tp_im_receiver(skcb) || j1939_cb_is_broadcast(skcb))
 			j1939_xtp_rx_rts(priv, skb, false);
 
 		break;
@@ -1984,7 +1995,7 @@ int j1939_tp_recv(struct j1939_priv *priv, struct sk_buff *skb)
 {
 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
 
-	if (!j1939_tp_im_involved_anydir(skcb))
+	if (!j1939_tp_im_involved_anydir(skcb) && !j1939_cb_is_broadcast(skcb))
 		return 0;
 
 	switch (skcb->addr.pgn) {
-- 
2.9.5