From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from gandalf.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) by passt.top (Postfix) with ESMTPS id 10CE35A0272 for ; Tue, 26 Mar 2024 06:42:31 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gibson.dropbear.id.au; s=202312; t=1711431746; bh=Cl6fcY3nV7lhRdGiZftIKXI18GuFCgoEVwfKHUY3lig=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OCU72NV+q+YmeS5/5GZ9vAJMccADYTgJrkCvbUUheWDsGqdKWefelmRTD0yn7mAU2 B0J5wRetlp4ZjmI+5vvXoLyMdh0+4h8UlCXjohdQwYUTlwvY29/9aiVXi8sk2DR8jZ TsDqBeIe1O/uZHAq8T/JZSa7vf6HR39xdA7zu1+NLDRDsljocRHMFv8zNl0r4nYJe3 p5nnC/1k9L05Bf29+8maGZFPehWddmc3OZmaqEifrfns9a2yU6ubIPZ9yRgW6yXNI+ Ilw8GLAAShaAPFF2kprjHNZpfswJJHC0Iy7n+TCpihgmYrHLxa3Q+MmNuoBt6Qg6Aj 3Qt0v7eFUnlyg== Received: by gandalf.ozlabs.org (Postfix, from userid 1007) id 4V3dwy5wyXz4wnr; Tue, 26 Mar 2024 16:42:26 +1100 (AEDT) From: David Gibson To: passt-dev@passt.top, Stefano Brivio Subject: [PATCH 1/4] tcp: Split handling of DUP_ACK from ACK Date: Tue, 26 Mar 2024 16:42:21 +1100 Message-ID: <20240326054224.716874-2-david@gibson.dropbear.id.au> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240326054224.716874-1-david@gibson.dropbear.id.au> References: <20240326054224.716874-1-david@gibson.dropbear.id.au> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Message-ID-Hash: OG2I5EJAFS33G42AR4NH4RVVLHQMHXHJ X-Message-ID-Hash: OG2I5EJAFS33G42AR4NH4RVVLHQMHXHJ X-MailFrom: dgibson@gandalf.ozlabs.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: maxi.rostock@outlook.de, pholzing@redhat.com, David Gibson X-Mailman-Version: 3.3.8 Precedence: list List-Id: Development discussion and patches for passt Archived-At: Archived-At: List-Archive: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: The DUP_ACK flag to tcp_send_flag() has two effects: first it forces the setting of the ACK flag in the packet, even if we otherwise wouldn't. Secondly, it causes a duplicate of the flags packet to be sent immediately after the first. Setting the ACK flag to tcp_send_flag() also has the first effect, so instead of having DUP_ACK also do that, pass both flags when we need both operations. This slightly simplifies the logic of tcp_send_flag() in a way that makes some future changes easier. Signed-off-by: David Gibson --- tcp.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tcp.c b/tcp.c index a1860d10..edd3d899 100644 --- a/tcp.c +++ b/tcp.c @@ -1677,7 +1677,7 @@ static int tcp_send_flag(struct ctx *c, struct tcp_tap_conn *conn, int flags) th->ack = !!(flags & ACK); } else { - th->ack = !!(flags & (ACK | DUP_ACK)) || + th->ack = !!(flags & ACK)) || conn->seq_ack_to_tap != prev_ack_to_tap || !prev_wnd_to_tap; } @@ -2503,7 +2503,7 @@ out: */ if (conn->seq_dup_ack_approx != (conn->seq_from_tap & 0xff)) { conn->seq_dup_ack_approx = conn->seq_from_tap & 0xff; - tcp_send_flag(c, conn, DUP_ACK); + tcp_send_flag(c, conn, ACK | DUP_ACK); } return p->count - idx; } -- 2.44.0