From mboxrd@z Thu Jan 1 00:00:00 1970 From: Martin KaFai Lau Subject: [PATCH net 0/2] tcp: Merge timestamp info when coalescing skbs Date: Tue, 19 Apr 2016 22:39:27 -0700 Message-ID: <1461130769-1442865-1-git-send-email-kafai@fb.com> Mime-Version: 1.0 Content-Type: text/plain Cc: Eric Dumazet , Neal Cardwell , Soheil Hassas Yeganeh , Willem de Bruijn , Yuchung Cheng , Kernel Team To: Return-path: Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:56430 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751791AbcDTFjz (ORCPT ); Wed, 20 Apr 2016 01:39:55 -0400 Received: from pps.filterd (m0044008.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.11/8.16.0.11) with SMTP id u3K5aPOl017661 for ; Tue, 19 Apr 2016 22:39:55 -0700 Received: from mail.thefacebook.com ([199.201.64.23]) by mx0a-00082601.pphosted.com with ESMTP id 22e2gs0axh-1 (version=TLSv1 cipher=AES128-SHA bits=128 verify=NOT) for ; Tue, 19 Apr 2016 22:39:55 -0700 Received: from facebook.com (2401:db00:11:d0a6:face:0:33:0) by mx-out.facebook.com (10.212.236.89) with ESMTP id 4de9107406ba11e6b2650002c95209d8-66d7c50 for ; Tue, 19 Apr 2016 22:39:52 -0700 Sender: netdev-owner@vger.kernel.org List-ID: This series is separated from the RFC series related to tcp_sendmsg(MSG_EOR) and it is targeting for the net branch. This patchset is focusing on fixing cases where TCP timestamp could be lost after coalescing skbs. A BPF prog is used to kprobe to sock_queue_err_skb() and print out the value of serr->ee.ee_data. The BPF prog (run-able from bcc) is attached here: BPF prog used for testing: ~~~~~ #!/usr/bin/env python from __future__ import print_function from bcc import BPF bpf_text = """ #include #include #include #include #ifdef memset #undef memset #endif int trace_err_skb(struct pt_regs *ctx) { struct sk_buff *skb = (struct sk_buff *)ctx->si; struct sock *sk = (struct sock *)ctx->di; struct sock_exterr_skb *serr; u32 ee_data = 0; if (!sk || !skb) return 0; serr = SKB_EXT_ERR(skb); bpf_probe_read(&ee_data, sizeof(ee_data), &serr->ee.ee_data); bpf_trace_printk("ee_data:%u\\n", ee_data); return 0; }; """ b = BPF(text=bpf_text) b.attach_kprobe(event="sock_queue_err_skb", fn_name="trace_err_skb") print("Attached to kprobe") b.trace_print()