Date: Fri, 18 Apr 2014 17:23:47 +0000 From: "Bjoern A. Zeeb" <bz@FreeBSD.org> To: Ian Lepore <ian@FreeBSD.org> Cc: svn-src-head@FreeBSD.org, svn-src-all@FreeBSD.org, src-committers@FreeBSD.org Subject: Re: svn commit: r264646 - head/sys/dev/netfpga10g/nf10bmac Message-ID: <E14B470F-CF7C-43E7-B7E6-8A89CC9C7286@FreeBSD.org> In-Reply-To: <1397831317.1124.301.camel@revolution.hippie.lan> References: <201404181421.s3IELAH0082972@svn.freebsd.org> <1397831317.1124.301.camel@revolution.hippie.lan>
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On 18 Apr 2014, at 14:28 , Ian Lepore <ian@FreeBSD.org> wrote: > On Fri, 2014-04-18 at 14:21 +0000, Bjoern A. Zeeb wrote: >> Author: bz >> Date: Fri Apr 18 14:21:10 2014 >> New Revision: 264646 >> URL: http://svnweb.freebsd.org/changeset/base/264646 >> >> Log: >> Now that I figured out where the ethernet addresses come from >> on NetFPGA-10G, assign one to the interface by default in a very >> similar way. >> >> MFC after: 6 days >> X-Easter-Egg-Hunt: yes >> >> Modified: >> head/sys/dev/netfpga10g/nf10bmac/if_nf10bmac.c >> >> Modified: head/sys/dev/netfpga10g/nf10bmac/if_nf10bmac.c >> ============================================================================== >> --- head/sys/dev/netfpga10g/nf10bmac/if_nf10bmac.c Fri Apr 18 12:51:30 2014 (r264645) >> +++ head/sys/dev/netfpga10g/nf10bmac/if_nf10bmac.c Fri Apr 18 14:21:10 2014 (r264646) >> @@ -446,7 +446,25 @@ static int >> nf10bmac_reset(struct nf10bmac_softc *sc) >> { >> >> - /* Currently we cannot do anything. */ >> + /* >> + * If we do not have an ether address set, initialize to the same >> + * OUI as NetFPGA-10G Linux driver does (which luckily seems >> + * unallocated). We just change the NIC specific part from >> + * the slightly long "\0NF10C0" to "\0NFBSD". >> + * Oh and we keep the way of setting it from a string as they do. >> + * It's an amazing way to hide it. >> + * XXX-BZ If NetFPGA gets their own OUI we should fix this. >> + */ >> + if (sc->nf10bmac_eth_addr[0] == 0x00 && >> + sc->nf10bmac_eth_addr[1] == 0x00 && >> + sc->nf10bmac_eth_addr[2] == 0x00 && >> + sc->nf10bmac_eth_addr[3] == 0x00 && >> + sc->nf10bmac_eth_addr[4] == 0x00 && >> + sc->nf10bmac_eth_addr[5] == 0x00) { >> + memcpy(&sc->nf10bmac_eth_addr, "\0NFBSD", ETHER_ADDR_LEN); >> + sc->nf10bmac_eth_addr[5] += sc->nf10bmac_unit; >> + } >> + >> return (0); >> } >> >> > > For other drivers/socs where we need to cook up an address on the fly, > we've used "bsd" as the OUI and a 24-bit random for the low order. > Aside from the nice aesthetic, 'bsd' has the "locally administered" bit > set and thus is g'teed to not clash with any globally assigned OUI. This is, as the comment, the commit message, and the XXX-BZ indicates, to be consistent with that platform. The change is only to not conflict with the host driver to avoid duplicate ethernet addresses when host PCI/DMA interfaces, and the “inside” PIO interfaces all talk to each other. If I’d do this another way, I’d (a) get a tiny slice from the official FreeBSD OUI and (b) put some random bits on the NIC part + the unit number. And, as we have learnt elsewhere, sys/net-admins are not always happy if you set the locally administered bit by default, as it’s them to assign the addresses and not the user. It’s a game you cannot globally win. This is about providing a “matching” default for the environment, and that’s why it sticks with what the platform is doing for now. /bz — Bjoern A. Zeeb "Come on. Learn, goddamn it.", WarGames, 1983
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