From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Subject: Re: [RFC 1/2] net: Support getting/setting RX-FCS in drivers. Date: Fri, 17 Jun 2011 13:20:12 +0100 Message-ID: <1308313212.11457.62.camel@localhost> References: <1308285007-11302-1-git-send-email-greearb@candelatech.com> <1308285007-11302-2-git-send-email-greearb@candelatech.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: greearb@candelatech.com Return-path: Received: from mail.solarflare.com ([216.237.3.220]:18948 "EHLO exchange.solarflare.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753567Ab1FQMUP (ORCPT ); Fri, 17 Jun 2011 08:20:15 -0400 In-Reply-To: <1308285007-11302-2-git-send-email-greearb@candelatech.com> Sender: netdev-owner@vger.kernel.org List-ID: On Thu, 2011-06-16 at 21:30 -0700, greearb@candelatech.com wrote: > From: Ben Greear > > This will allow us to enable/disable having the Ethernet > frame checksum appended to the skb. Enabling this is > useful when sniffing packets. > > In particular, this can be used to test logic that allows > a NIC to receive all frames, even ones with bad checksums. > > Signed-off-by: Ben Greear > --- > :100644 100644 439b173... e5e8747... M include/linux/ethtool.h > :100644 100644 fd14116... b36bac7... M net/core/ethtool.c > include/linux/ethtool.h | 5 +++++ > net/core/ethtool.c | 38 ++++++++++++++++++++++++++++++++++++++ > 2 files changed, 43 insertions(+), 0 deletions(-) > > diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h > index 439b173..e5e8747 100644 > --- a/include/linux/ethtool.h > +++ b/include/linux/ethtool.h > @@ -955,6 +955,8 @@ struct ethtool_ops { > int (*get_dump_data)(struct net_device *, > struct ethtool_dump *, void *); > int (*set_dump)(struct net_device *, struct ethtool_dump *); > + int (*set_save_fcs)(struct net_device *, u32); > + int (*get_save_fcs)(struct net_device *, u32 *); These need to be described in the kernel-doc. Why do these function names use 'save_fcs' whereas the command names use 'RXFCS'? > }; > #endif /* __KERNEL__ */ > @@ -1029,6 +1031,9 @@ struct ethtool_ops { > #define ETHTOOL_SET_DUMP 0x0000003e /* Set dump settings */ > #define ETHTOOL_GET_DUMP_FLAG 0x0000003f /* Get dump settings */ > #define ETHTOOL_GET_DUMP_DATA 0x00000040 /* Get dump data */ > +#define ETHTOOL_GETRXFCS 0x00000041 /* Get RX Save Frame Checksum */ > +#define ETHTOOL_SETRXFCS 0x00000042 /* Set RX Save Frame Checksum */ > + > > /* compatibility with older code */ > #define SPARC_ETH_GSET ETHTOOL_GSET > diff --git a/net/core/ethtool.c b/net/core/ethtool.c > index fd14116..b36bac7 100644 > --- a/net/core/ethtool.c > +++ b/net/core/ethtool.c > @@ -1927,6 +1927,38 @@ out: > return ret; > } > > +static int ethtool_get_rx_fcs(struct net_device *dev, void __user *useraddr) > +{ > + struct ethtool_value edata; > + int rv = 0; > + > + if (!dev->ethtool_ops->get_save_fcs) > + return -EOPNOTSUPP; > + > + rv = dev->ethtool_ops->get_save_fcs(dev, &edata.data); > + if (rv < 0) > + return rv; > + > + if (copy_to_user(useraddr, &edata, sizeof(edata))) > + return -EFAULT; > + return 0; > +} > + > + > +static int ethtool_set_rx_fcs(struct net_device *dev, void __user *useraddr) > +{ > + struct ethtool_value id; > + > + if (!dev->ethtool_ops->set_save_fcs) > + return -EOPNOTSUPP; > + > + if (copy_from_user(&id, useraddr, sizeof(id))) > + return -EFAULT; > + > + return dev->ethtool_ops->set_save_fcs(dev, id.data); > +} > + > + > /* The main entry point in this file. Called from net/core/dev.c */ > > int dev_ethtool(struct net *net, struct ifreq *ifr) > @@ -2152,6 +2184,12 @@ int dev_ethtool(struct net *net, struct ifreq *ifr) > case ETHTOOL_GET_DUMP_DATA: > rc = ethtool_get_dump_data(dev, useraddr); > break; > + case ETHTOOL_SETRXFCS: > + rc = ethtool_set_rx_fcs(dev, useraddr); > + break; > + case ETHTOOL_GETRXFCS: > + rc = ethtool_get_rx_fcs(dev, useraddr); > + break; You can use ethtool_{get,set}_value() rather than adding new trivial functions. And as Michal says, this could reasonably be a feature not an entirely separate flag. I'm not sure it's that important to have debugging flags in features, but I also don't want to have 2 commands per flag... Ben. > default: > rc = -EOPNOTSUPP; > } -- Ben Hutchings, Senior Software Engineer, Solarflare Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked.