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authorJakub Kicinski <kuba@kernel.org>2023-02-09 23:05:25 +0300
committerJakub Kicinski <kuba@kernel.org>2023-02-09 23:25:40 +0300
commit8697a258ae24703267d2a37d91ab757c91ef027e (patch)
tree7a1798898ac64c72e6cf77d2320f036c963a16c1 /net/can
parent0b34d68049b09821499b93d50b5a9d7d2ca449f6 (diff)
parent35674e787518768626d3a0ffce1c13a7eeed922d (diff)
downloadlinux-8697a258ae24703267d2a37d91ab757c91ef027e.tar.xz
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
net/devlink/leftover.c / net/core/devlink.c: 565b4824c39f ("devlink: change port event netdev notifier from per-net to global") f05bd8ebeb69 ("devlink: move code to a dedicated directory") 687125b5799c ("devlink: split out core code") https://lore.kernel.org/all/20230208094657.379f2b1a@canb.auug.org.au/ Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/can')
-rw-r--r--net/can/j1939/address-claim.c40
1 files changed, 40 insertions, 0 deletions
diff --git a/net/can/j1939/address-claim.c b/net/can/j1939/address-claim.c
index f33c47327927..ca4ad6cdd5cb 100644
--- a/net/can/j1939/address-claim.c
+++ b/net/can/j1939/address-claim.c
@@ -165,6 +165,46 @@ static void j1939_ac_process(struct j1939_priv *priv, struct sk_buff *skb)
* leaving this function.
*/
ecu = j1939_ecu_get_by_name_locked(priv, name);
+
+ if (ecu && ecu->addr == skcb->addr.sa) {
+ /* The ISO 11783-5 standard, in "4.5.2 - Address claim
+ * requirements", states:
+ * d) No CF shall begin, or resume, transmission on the
+ * network until 250 ms after it has successfully claimed
+ * an address except when responding to a request for
+ * address-claimed.
+ *
+ * But "Figure 6" and "Figure 7" in "4.5.4.2 - Address-claim
+ * prioritization" show that the CF begins the transmission
+ * after 250 ms from the first AC (address-claimed) message
+ * even if it sends another AC message during that time window
+ * to resolve the address contention with another CF.
+ *
+ * As stated in "4.4.2.3 - Address-claimed message":
+ * In order to successfully claim an address, the CF sending
+ * an address claimed message shall not receive a contending
+ * claim from another CF for at least 250 ms.
+ *
+ * As stated in "4.4.3.2 - NAME management (NM) message":
+ * 1) A commanding CF can
+ * d) request that a CF with a specified NAME transmit
+ * the address-claimed message with its current NAME.
+ * 2) A target CF shall
+ * d) send an address-claimed message in response to a
+ * request for a matching NAME
+ *
+ * Taking the above arguments into account, the 250 ms wait is
+ * requested only during network initialization.
+ *
+ * Do not restart the timer on AC message if both the NAME and
+ * the address match and so if the address has already been
+ * claimed (timer has expired) or the AC message has been sent
+ * to resolve the contention with another CF (timer is still
+ * running).
+ */
+ goto out_ecu_put;
+ }
+
if (!ecu && j1939_address_is_unicast(skcb->addr.sa))
ecu = j1939_ecu_create_locked(priv, name);