From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Kurt Kanzenbach DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1597921073; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=YIkdj2DyvYAhQ7RBBwnYw5GJ1OBharqxpJPUklg5BVY=; b=sQO1KRzu+ln6rYasVnJrj+dGujnRJIpdNi4SZQtH+HfrsqdMiTtzuNUcWd+pR2CoNW0rCB QvrGeuIQTuBdDAri4DtyW05dShPyZxpGqXYOmdWOgyqTlOXsiQ4PfFMzlHg2b37lWXVyIs OapnL0xcMSIt0iVPgXP2Tar+YU4CDjW+NqCgAtB+5mal2kxMNyCaWYNhOI2IdL5V7zEklv sJHnoBnVnMUWxSXhSM4+KIt1vvM6hqgabUWoqTR0AaWapyjHuiOXFDCBhNNRzikKGcFG48 Xgwe7xDdmWD1SLEm7eDXKKN24d1L0Rqw4HCpQCz4PnEavoNCViZ0uXWguW7FsQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1597921073; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=YIkdj2DyvYAhQ7RBBwnYw5GJ1OBharqxpJPUklg5BVY=; b=GLQ1GQMkBs9itAqx6i75aleyoPHKCFjC143w8bmpAZT8W4yQ72xQ2NT1XNirW4bEmSUexd ea6Ua9vT7ucZ+ZDA== Date: Thu, 20 Aug 2020 12:57:37 +0200 Message-Id: <20200820105737.5089-1-kurt@linutronix.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [Bridge] [RFC PATCH] net: bridge: Don't reset time stamps on SO_TXTIME enabled sockets List-Id: Linux Ethernet Bridging List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Roopa Prabhu , Nikolay Aleksandrov Cc: Kurt Kanzenbach , Jakub Kicinski , bridge@lists.linux-foundation.org, "David S. Miller" , netdev@vger.kernel.org When using the ETF Qdisc in combination with a bridge and DSA, then all packets gets dropped due to invalid time stamps. The setup looks like this: Transmit path: Application -> bridge (br0) -> DSA slave ports (lan0, lan1) -> ETF Qdisc -> ethernet (eth0) The user space application uses SO_TXTIME to attach a sending time stamp for each packet using the corresponding interface. That time stamp is then attached to the skb in the kernel. The first network device involved in the chain is the bridge device. However, in br_forward_finish() the time stamp is reset to zero unconditionally. Meaning when the skb arrives at the ETF Qdisc, it's dropped as invalid because the time stamp is zero. The reset of the time stamp in the bridge code is there for a good reason. See commit 41d1c8839e5f ("net: clear skb->tstamp in bridge forwarding path") Therefore, add a conditional for SO_TXTIME enabled sockets. Signed-off-by: Kurt Kanzenbach --- net/bridge/br_forward.c | 9 +++++++++ 1 file changed, 9 insertions(+) RFC, because I don't know if that's the correct way to solve that issue. diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c index 7629b63f6f30..e5f7e49ed91d 100644 --- a/net/bridge/br_forward.c +++ b/net/bridge/br_forward.c @@ -15,6 +15,7 @@ #include #include #include +#include #include "br_private.h" /* Don't forward packets to originating port or forwarding disabled */ @@ -61,7 +62,15 @@ EXPORT_SYMBOL_GPL(br_dev_queue_push_xmit); int br_forward_finish(struct net *net, struct sock *sk, struct sk_buff *skb) { + /* When applications provide time stamps for packets via SO_TXTIME + * socket option, then don't reset it. + */ + if (skb->sk && sock_flag(skb->sk, SOCK_TXTIME)) + goto finish; + skb->tstamp = 0; + +finish: return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING, net, sk, skb, NULL, skb->dev, br_dev_queue_push_xmit); -- 2.20.1