From patchwork Fri Feb 21 01:29:21 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Uday Shankar X-Patchwork-Id: 13984727 X-Patchwork-Delegate: kuba@kernel.org Received: from mail-qv1-f98.google.com (mail-qv1-f98.google.com [209.85.219.98]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F2B7278F4E for ; Fri, 21 Feb 2025 01:29:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.98 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740101375; cv=none; b=hgqIN7r7ULqi9ZG2YGrcacvYn7pYSUvPV/lbErVpjVqihOqoPEoZ0dquJnhRlbiLD8sA/cg1hWxk0TQqfcpOpswGQVAdmr9uw2QSne+ihMzIl2THTnYA/2OSwYaxNIqgidaF/A/Srhj14Jnl2Wblufbvj+F5OkAJsdvJJ7LeHuY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740101375; c=relaxed/simple; bh=ndXTYWnD0dGmJ/CTps1hj3PgFz/Squ4fkXCPkynjP7Q=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=MlGVFHxtQbiSJ7DhiLnUwUK8hpg/emjluO6juHuzFpvIc1ByqjB7OY0c6tix4zmfsWR7f75ViY2r2A8AQ2Vh9L60fSnWJ6RlYh81BIf99KrYh7HNx8d2Ff9n60TLsbIherS8dBii3g5Uk3c+fUUGyzmGMwHKL6UfeZ2HyR66neo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=purestorage.com; spf=fail smtp.mailfrom=purestorage.com; dkim=pass (2048-bit key) header.d=purestorage.com header.i=@purestorage.com header.b=QCAX5AbV; arc=none smtp.client-ip=209.85.219.98 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=purestorage.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=purestorage.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=purestorage.com header.i=@purestorage.com header.b="QCAX5AbV" Received: by mail-qv1-f98.google.com with SMTP id 6a1803df08f44-6e6846bcde2so13126986d6.1 for ; Thu, 20 Feb 2025 17:29:32 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=purestorage.com; s=google2022; t=1740101372; x=1740706172; darn=vger.kernel.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:from:to:cc:subject:date:message-id :reply-to; bh=HkZ3MuwsfFvPuUcCGF9IbI3/TlNqWSAvIHqD4D2Ewrs=; b=QCAX5AbVmCAq7LShtgcnYhPPTaEqE3oI43y+O3PtT1qedJtp530nQXh6T6uXjOv7lD WNtr3CY6F2FwOzfQcNeW/e4kd3sKQAViq/kRSYDn6y+IfK0WKPkPsRWWoLoUHzutuKzq lL68kg4xaRb98K/uk0ge3WUEsNwQRsb/VwiuY/CvlLKWhnOczrEZR2GH5V93xIRxpxB5 h6tty09nixLbH28p5XqDyQPL+PAHX1AM5NoTxdmnfp1r5S/PNjFtEyWZuf3gXaaW3o5Y TMHOPgKFHv/4tpqo4ns17bYabbVGZBwJFgAMlCwbwdB5O5faFEJ4Qk20lRwD41TLqTfh cVRw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1740101372; x=1740706172; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=HkZ3MuwsfFvPuUcCGF9IbI3/TlNqWSAvIHqD4D2Ewrs=; b=skJ6iOwzciV+BLlOLQ4Ftd933UsSG1LbSsw5KpsvhFS5QVvtpN1GFOIVgNJbRxz9FN V9R4d4Znd8fJTkW+wkAUU2v/l++mBZ8QJFWdNxSHlpJTkcRyPV3+2PjN4BKPAkf1wNM/ T4cwINaJVPzG5OjsBgCBi50KtTFuiuAK565nHQtgsAWZHYoqFEmVRCxDFnyccxAUyGJ/ 74m3mC7Abtbw8b5L/JWMBmw54BWLD/RAmuRfTzICopjRNqeY466dRNVl19IaGWOhGzYm JvjpK//WrSO1lLYQnbkrBVQk9e7J7XX2vFZGu+ToL43vpzo44jGZ8hDpig5sdr+bmpQO vgag== X-Gm-Message-State: AOJu0YzI2598H0SxQehPyjyQWubQElk+oPt+dj67k+POxUXHbg3Wf2ou D/kwN2dJuyyO9vXIXilhogmB9OIcCIZLCt+TsLPRmbSdJEzsW1Sz9fkVg5rP1hiMDVQG/YcuKUA gy+8Vt8cpzraGZQYfhk3Rthq3bxcS+Ap+ISkiJao9l116OJK7 X-Gm-Gg: ASbGnctu5yeZSmRoiSYyzrcAVKQZhwwplgH69EsHShJDLB+YpBoIhzaGhHyrHlTH5Xu TkAy0evx1g1iX+dEIyuwbuuprynY4adn9hZWOiYpdeqXQEISbqA5jtXAPyU+3yms7rhY5XBRT5F Yf1O3rXiXhtcXbUhP6DPDFNwZW1SVitN1twVEDfKcyCl0+G+nGaYj9yRtJKbSeGVB+pJxdMluDf Sq4fY8t1gyGFdeZm63+JFgmSxJN4LUJpn7qUmLyGgGYQJZdlqOPR0XBjOc5gjRVknNVJTqK+NQP H4d1QVribzKcEZuElBfqFX52z8pS/mJHlBI= X-Google-Smtp-Source: AGHT+IEa3vOQr99biY5aI/mCrtL5nOIl2f7qIkNP4WURSdEvcIztDurG/2JnI2tlgCrBA+xw2s3dSrIaNNsw X-Received: by 2002:ad4:5fcc:0:b0:6e6:6a93:10fd with SMTP id 6a1803df08f44-6e6aea1b96amr21883416d6.45.1740101371745; Thu, 20 Feb 2025 17:29:31 -0800 (PST) Received: from c7-smtp-2023.dev.purestorage.com ([2620:125:9017:12:36:3:5:0]) by smtp-relay.gmail.com with ESMTPS id 6a1803df08f44-6e65d73479fsm6496886d6.16.2025.02.20.17.29.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Feb 2025 17:29:31 -0800 (PST) X-Relaying-Domain: purestorage.com Received: from dev-ushankar.dev.purestorage.com (dev-ushankar.dev.purestorage.com [IPv6:2620:125:9007:640:7:70:36:0]) by c7-smtp-2023.dev.purestorage.com (Postfix) with ESMTP id 86C90340216; Thu, 20 Feb 2025 18:29:30 -0700 (MST) Received: by dev-ushankar.dev.purestorage.com (Postfix, from userid 1557716368) id 7B3CCE55F29; Thu, 20 Feb 2025 18:29:29 -0700 (MST) From: Uday Shankar Date: Thu, 20 Feb 2025 18:29:21 -0700 Subject: [PATCH net-next v5 2/2] netconsole: allow selection of egress interface via MAC address Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20250220-netconsole-v5-2-4aeafa71debf@purestorage.com> References: <20250220-netconsole-v5-0-4aeafa71debf@purestorage.com> In-Reply-To: <20250220-netconsole-v5-0-4aeafa71debf@purestorage.com> To: Breno Leitao , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Srinivas Kandagatla , =?utf-8?b?UmFmYcWC?= =?utf-8?b?IE1pxYJlY2tp?= , Simon Horman , Andrew Morton , Johannes Berg , Jonathan Corbet Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org, linux-doc@vger.kernel.org, Uday Shankar X-Mailer: b4 0.14.2 X-Patchwork-Delegate: kuba@kernel.org Currently, netconsole has two methods of configuration - module parameter and configfs. The former interface allows for netconsole activation earlier during boot (by specifying the module parameter on the kernel command line), so it is preferred for debugging issues which arise before userspace is up/the configfs interface can be used. The module parameter syntax requires specifying the egress interface name. This requirement makes it hard to use for a couple reasons: - The egress interface name can be hard or impossible to predict. For example, installing a new network card in a system can change the interface names assigned by the kernel. - When constructing the module parameter, one may have trouble determining the original (kernel-assigned) name of the interface (which is the name that should be given to netconsole) if some stable interface naming scheme is in effect. A human can usually look at kernel logs to determine the original name, but this is very painful if automation is constructing the parameter. For these reasons, allow selection of the egress interface via MAC address when configuring netconsole using the module parameter. Update the netconsole documentation with an example of the new syntax. Selection of egress interface by MAC address via configfs is far less interesting (since when this interface can be used, one should be able to easily convert between MAC address and interface name), so it is left unimplemented. Signed-off-by: Uday Shankar Reviewed-by: Breno Leitao Tested-by: Breno Leitao --- Documentation/networking/netconsole.rst | 6 +++- include/linux/netpoll.h | 6 ++++ net/core/netpoll.c | 51 +++++++++++++++++++++++++-------- 3 files changed, 50 insertions(+), 13 deletions(-) diff --git a/Documentation/networking/netconsole.rst b/Documentation/networking/netconsole.rst index 84803c59968a3237012fab821f432eb531aba45c..4b0f32ed5c635dbce594bc09e5d25c7654350779 100644 --- a/Documentation/networking/netconsole.rst +++ b/Documentation/networking/netconsole.rst @@ -47,7 +47,7 @@ following format:: r if present, prepend kernel version (release) to the message src-port source for UDP packets (defaults to 6665) src-ip source IP to use (interface address) - dev network interface (eth0) + dev network interface name (eth0) or MAC address tgt-port port for logging agent (6666) tgt-ip IP address for logging agent tgt-macaddr ethernet MAC address for logging agent (broadcast) @@ -64,6 +64,10 @@ or using IPv6:: insmod netconsole netconsole=@/,@fd00:1:2:3::1/ +or using a MAC address to select the egress interface:: + + linux netconsole=4444@10.0.0.1/22:33:44:55:66:77,9353@10.0.0.2/12:34:56:78:9a:bc + It also supports logging to multiple remote agents by specifying parameters for the multiple agents separated by semicolons and the complete string enclosed in "quotes", thusly:: diff --git a/include/linux/netpoll.h b/include/linux/netpoll.h index f91e50a76efd4b016381c632456397eea1ea877f..1ade65b59be49cfdcf86ed6e938287b949aa9f58 100644 --- a/include/linux/netpoll.h +++ b/include/linux/netpoll.h @@ -25,7 +25,13 @@ union inet_addr { struct netpoll { struct net_device *dev; netdevice_tracker dev_tracker; + /* + * Either dev_name or dev_mac can be used to specify the local + * interface - dev_name is used if it is a nonempty string, else + * dev_mac is used. + */ char dev_name[IFNAMSIZ]; + u8 dev_mac[ETH_ALEN]; const char *name; union inet_addr local_ip, remote_ip; diff --git a/net/core/netpoll.c b/net/core/netpoll.c index 62b4041aae1ae8c7dc47c89fb40b14bbd4ad0e0e..64c08b845c92bb2a2165de6dfba95dede2b581db 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -501,7 +501,8 @@ void netpoll_print_options(struct netpoll *np) np_info(np, "local IPv6 address %pI6c\n", &np->local_ip.in6); else np_info(np, "local IPv4 address %pI4\n", &np->local_ip.ip); - np_info(np, "interface '%s'\n", np->dev_name); + np_info(np, "interface name '%s'\n", np->dev_name); + np_info(np, "local ethernet address '%pM'\n", np->dev_mac); np_info(np, "remote port %d\n", np->remote_port); if (np->ipv6) np_info(np, "remote IPv6 address %pI6c\n", &np->remote_ip.in6); @@ -570,11 +571,18 @@ int netpoll_parse_options(struct netpoll *np, char *opt) cur++; if (*cur != ',') { - /* parse out dev name */ + /* parse out dev_name or dev_mac */ if ((delim = strchr(cur, ',')) == NULL) goto parse_failed; *delim = 0; - strscpy(np->dev_name, cur, sizeof(np->dev_name)); + + np->dev_name[0] = '\0'; + eth_broadcast_addr(np->dev_mac); + if (!strchr(cur, ':')) + strscpy(np->dev_name, cur, sizeof(np->dev_name)); + else if (!mac_pton(cur, np->dev_mac)) + goto parse_failed; + cur = delim; } cur++; @@ -679,27 +687,45 @@ int __netpoll_setup(struct netpoll *np, struct net_device *ndev) } EXPORT_SYMBOL_GPL(__netpoll_setup); +/* + * Returns a pointer to a string representation of the identifier used + * to select the egress interface for the given netpoll instance. buf + * must be a buffer of length at least MAC_ADDR_STR_LEN + 1. + */ +static char *egress_dev(struct netpoll *np, char *buf) +{ + if (np->dev_name[0]) + return np->dev_name; + + snprintf(buf, MAC_ADDR_STR_LEN, "%pM", np->dev_mac); + return buf; +} + int netpoll_setup(struct netpoll *np) { + struct net *net = current->nsproxy->net_ns; + char buf[MAC_ADDR_STR_LEN + 1]; struct net_device *ndev = NULL; bool ip_overwritten = false; struct in_device *in_dev; int err; rtnl_lock(); - if (np->dev_name[0]) { - struct net *net = current->nsproxy->net_ns; + if (np->dev_name[0]) ndev = __dev_get_by_name(net, np->dev_name); - } + else if (is_valid_ether_addr(np->dev_mac)) + ndev = dev_getbyhwaddr(net, ARPHRD_ETHER, np->dev_mac); + if (!ndev) { - np_err(np, "%s doesn't exist, aborting\n", np->dev_name); + np_err(np, "%s doesn't exist, aborting\n", egress_dev(np, buf)); err = -ENODEV; goto unlock; } netdev_hold(ndev, &np->dev_tracker, GFP_KERNEL); if (netdev_master_upper_dev_get(ndev)) { - np_err(np, "%s is a slave device, aborting\n", np->dev_name); + np_err(np, "%s is a slave device, aborting\n", + egress_dev(np, buf)); err = -EBUSY; goto put; } @@ -707,7 +733,8 @@ int netpoll_setup(struct netpoll *np) if (!netif_running(ndev)) { unsigned long atmost; - np_info(np, "device %s not up yet, forcing it\n", np->dev_name); + np_info(np, "device %s not up yet, forcing it\n", + egress_dev(np, buf)); err = dev_open(ndev, NULL); @@ -741,7 +768,7 @@ int netpoll_setup(struct netpoll *np) if (!ifa) { put_noaddr: np_err(np, "no IP address for %s, aborting\n", - np->dev_name); + egress_dev(np, buf)); err = -EDESTADDRREQ; goto put; } @@ -772,13 +799,13 @@ int netpoll_setup(struct netpoll *np) } if (err) { np_err(np, "no IPv6 address for %s, aborting\n", - np->dev_name); + egress_dev(np, buf)); goto put; } else np_info(np, "local IPv6 %pI6c\n", &np->local_ip.in6); #else np_err(np, "IPv6 is not supported %s, aborting\n", - np->dev_name); + egress_dev(np, buf)); err = -EINVAL; goto put; #endif