From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by passt.top (Postfix) with ESMTP id 74F4F5A026D for ; Fri, 7 Jul 2023 22:35:30 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1688762129; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=oS4Ef94kBPyPGVez0R+vx6OqPueLiAMErgl30uPFQHw=; b=Ve3lPM0QpL7Vpiy9WsOG2BypAgSNxr+cIQtbhkmaMgsSbjrneljQwxjE+xya2OHOS0bALX dZc68jqTvFyDlDyfj2sLKM79DgBmS14tBu7d9vDUIGmYBpUCHqA1pHqDvpnEqv9AioZNqw HYBKkDDY3dVc4N1+BmDH+FnuNbJeheY= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-370-tOU03XJvPx6cDXBBeRtAOw-1; Fri, 07 Jul 2023 16:35:28 -0400 X-MC-Unique: tOU03XJvPx6cDXBBeRtAOw-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id E9AE4101A54E; Fri, 7 Jul 2023 20:35:27 +0000 (UTC) Received: from elisabeth (unknown [10.39.208.30]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 45152F66A8; Fri, 7 Jul 2023 20:35:26 +0000 (UTC) Date: Fri, 7 Jul 2023 22:35:25 +0200 From: Stefano Brivio To: David Gibson Subject: Re: [PATCH v2] tap: Explicitly drop IPv4 fragments, and give a warning Message-ID: <20230707223525.01ba0510@elisabeth> In-Reply-To: <20230705043516.1237808-1-david@gibson.dropbear.id.au> References: <20230705043516.1237808-1-david@gibson.dropbear.id.au> Organization: Red Hat MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Message-ID-Hash: INBJ7M3X53FXOPHDDQ52CKNUXAJYBJSP X-Message-ID-Hash: INBJ7M3X53FXOPHDDQ52CKNUXAJYBJSP X-MailFrom: sbrivio@redhat.com 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: passt-dev@passt.top 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: On Wed, 5 Jul 2023 14:35:16 +1000 David Gibson wrote: > We don't handle defragmentation of IP packets coming from the tap side, > and we're unlikely to any time soon (with our large MTU, it's not useful > for practical use cases). Currently, however, we simply ignore the > fragmentation flags and treat fragments as though they were whole IP > packets. This isn't ideal and can lead to rather cryptic behaviour if we > do receive IP fragments. > > Change the code to explicitly drop fragmented packets, and print a rate > limited warning if we do encounter them. > > Link: https://bugs.passt.top/show_bug.cgi?id=62 > > Signed-off-by: David Gibson Applied. -- Stefano