Date: Mon, 13 Jul 2026 11:36:16 +0200 (CEST) From: Ronald Klop <ronald-lists@klop.ws> To: Michal Meloun <mmel@FreeBSD.org> Cc: dev-commits-src-all@FreeBSD.org, src-committers@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: Re: git: 920518cf2e75 - main - FDT: implement fdt_ether_get_addr() Message-ID: <286652666.1198.1783935376299@localhost> In-Reply-To: <6a54a3a6.3466a.6cbf6a26@gitrepo.freebsd.org>
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[-- Attachment #1 --] Hi, Nice work! I like the usage of ether_gen_addr for user friendliness when no MAC is known. I did some work on ether_gen_addr in the past and back then I had a situation that an ifp was not (yet) available so I added ether_gen_addr_byname. Somebody (I can look it up if needed) agreed on this and said that ether_gen_addr using ifp is actually a layering violation. So you might take a look if it is easy to pass in the interface name and call ether_gen_addr_byname instead of using the ifp. Regards, Ronald. Van: Michal Meloun <mmel@FreeBSD.org> Datum: maandag, 13 juli 2026 10:36 Aan: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Onderwerp: git: 920518cf2e75 - main - FDT: implement fdt_ether_get_addr() > > The branch main has been updated by mmel: > > URL: https://cgit.FreeBSD.org/src/commit/?id=920518cf2e75012135104886d92814c048baa2fb > > commit 920518cf2e75012135104886d92814c048baa2fb > Author: Michal Meloun <mmel@FreeBSD.org> > AuthorDate: 2026-07-13 08:34:22 +0000 > Commit: Michal Meloun <mmel@FreeBSD.org> > CommitDate: 2026-07-13 08:35:47 +0000 > > FDT: implement fdt_ether_get_addr() > > Introduce fdt_ether_get_addr() in fdt_common.c/h that tries standard > DT properties in the correct order and falls back to a random address > when needed. This should be used by ethernet drivers instead of open-coding > the same logic. > > MFC after: 2 weeks > > Reviewed by: mhorne, adrian, bz, jrtc27 > Differential Revision: https://reviews.freebsd.org/D58104 > --- > sys/dev/fdt/fdt_common.c | 40 ++++++++++++++++++++++++++++++++++++++++ > sys/dev/fdt/fdt_common.h | 4 ++++ > 2 files changed, 44 insertions(+) > > diff --git a/sys/dev/fdt/fdt_common.c b/sys/dev/fdt/fdt_common.c > index f43551c6310e..93897b598b30 100644 > --- a/sys/dev/fdt/fdt_common.c > +++ b/sys/dev/fdt/fdt_common.c > @@ -553,3 +553,43 @@ fdt_get_chosen_bootargs(char *bootargs, size_t max_size) > return (ENXIO); > return (0); > } > + > +/* > + * fdt_ether_get_addr - Get ethernet MAC address using FDT properties. > + * Order: > + * 1. "mac-address" > + * 2. "local-mac-address" > + * 3. Keep pre-initialized value (if valid) > + * 4. random ether_gen_addr() as last resort > + */ > +void > +fdt_ether_get_addr(phandle_t node, struct ifnet *ifp, uint8_t *eaddr) > +{ > + uint8_t tmp[ETHER_ADDR_LEN]; > + int len; > + > + /* Firstly try "mac-address" */ > + len = OF_getprop(node, "mac-address", tmp, sizeof(tmp)); > + if (len == ETHER_ADDR_LEN && !ETHER_IS_ZERO(tmp) && > + !ETHER_IS_MULTICAST(tmp)) { > + bcopy(tmp, eaddr, ETHER_ADDR_LEN); > + return; > + } > + > + /* Next use "local-mac-address" */ > + len = OF_getprop(node, "local-mac-address", tmp, sizeof(tmp)); > + if (len == ETHER_ADDR_LEN && !ETHER_IS_ZERO(tmp) && > + !ETHER_IS_MULTICAST(tmp)) { > + bcopy(tmp, eaddr, ETHER_ADDR_LEN); > + return; > + } > + > + /* Next use existing one if set */ > + if (!ETHER_IS_ZERO(eaddr) && !ETHER_IS_MULTICAST(eaddr)) > + return; > + > + /* Last resort - generate random one */ > + ether_gen_addr(ifp, (struct ether_addr *)eaddr); > + > + return; > +} > diff --git a/sys/dev/fdt/fdt_common.h b/sys/dev/fdt/fdt_common.h > index f597233f9771..3eee6913ad72 100644 > --- a/sys/dev/fdt/fdt_common.h > +++ b/sys/dev/fdt/fdt_common.h > @@ -33,8 +33,11 @@ > > #include <sys/sysctl.h> > #include <sys/slicer.h> > +#include <sys/socket.h> > #include <contrib/libfdt/libfdt_env.h> > #include <dev/ofw/ofw_bus.h> > +#include <net/ethernet.h> > +#include <net/if.h> > > #define FDT_MEM_REGIONS 64 > > @@ -70,6 +73,7 @@ typedef void (*fdt_mem_region_cb)(const struct mem_region *, void *); > int fdt_addrsize_cells(phandle_t, int *, int *); > u_long fdt_data_get(const void *, int); > int fdt_data_to_res(const pcell_t *, int, int, u_long *, u_long *); > +void fdt_ether_get_addr(phandle_t node, struct ifnet *ifp, uint8_t *eaddr); > phandle_t fdt_find_compatible(phandle_t, const char *, int); > phandle_t fdt_depth_search_compatible(phandle_t, const char *, int); > int fdt_foreach_mem_region(fdt_mem_region_cb, void *); > > > > [-- Attachment #2 --] <html><head></head><body>Hi,<br> <br> Nice work! I like the usage of ether_gen_addr for user friendliness when no MAC is known.<br> <br> I did some work on ether_gen_addr in the past and back then I had a situation that an ifp was not (yet) available so I added ether_gen_addr_byname. Somebody (I can look it up if needed) agreed on this and said that ether_gen_addr using ifp is actually a layering violation.<br> So you might take a look if it is easy to pass in the interface name and call ether_gen_addr_byname instead of using the ifp.<br> <br> Regards,<br> Ronald.<br> <br> <p><strong>Van:</strong> Michal Meloun <mmel@FreeBSD.org><br> <strong>Datum:</strong> maandag, 13 juli 2026 10:36<br> <strong>Aan:</strong> src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org<br> <strong>Onderwerp:</strong> git: 920518cf2e75 - main - FDT: implement fdt_ether_get_addr()</p> <blockquote style="padding-right: 0px; padding-left: 5px; margin-left: 5px; border-left: #000000 2px solid; margin-right: 0px"> <div class="MessageRFC822Viewer" id="P"> <div class="TextPlainViewer" id="P.P">The branch main has been updated by mmel:<br> <br> URL: <a href="https://cgit.FreeBSD.org/src/commit/?id=920518cf2e75012135104886d92814c048baa2fb">https://cgit.FreeBSD.org/src/commit/?id=920518cf2e75012135104886d92814c048baa2fb</a><br>; <br> commit 920518cf2e75012135104886d92814c048baa2fb<br> Author: Michal Meloun <mmel@FreeBSD.org><br> AuthorDate: 2026-07-13 08:34:22 +0000<br> Commit: Michal Meloun <mmel@FreeBSD.org><br> CommitDate: 2026-07-13 08:35:47 +0000<br> <br> FDT: implement fdt_ether_get_addr()<br> <br> Introduce fdt_ether_get_addr() in fdt_common.c/h that tries standard<br> DT properties in the correct order and falls back to a random address<br> when needed. This should be used by ethernet drivers instead of open-coding<br> the same logic.<br> <br> MFC after: 2 weeks<br> <br> Reviewed by: mhorne, adrian, bz, jrtc27<br> Differential Revision: <a href="https://reviews.freebsd.org/D58104">https://reviews.freebsd.org/D58104</a><br>; ---<br> sys/dev/fdt/fdt_common.c | 40 ++++++++++++++++++++++++++++++++++++++++<br> sys/dev/fdt/fdt_common.h | 4 ++++<br> 2 files changed, 44 insertions(+)<br> <br> diff --git a/sys/dev/fdt/fdt_common.c b/sys/dev/fdt/fdt_common.c<br> index f43551c6310e..93897b598b30 100644<br> --- a/sys/dev/fdt/fdt_common.c<br> +++ b/sys/dev/fdt/fdt_common.c<br> @@ -553,3 +553,43 @@ fdt_get_chosen_bootargs(char *bootargs, size_t max_size)<br> return (ENXIO);<br> return (0);<br> }<br> +<br> +/*<br> + * fdt_ether_get_addr - Get ethernet MAC address using FDT properties.<br> + * Order:<br> + * 1. "mac-address"<br> + * 2. "local-mac-address"<br> + * 3. Keep pre-initialized value (if valid)<br> + * 4. random ether_gen_addr() as last resort<br> + */<br> +void<br> +fdt_ether_get_addr(phandle_t node, struct ifnet *ifp, uint8_t *eaddr)<br> +{<br> + uint8_t tmp[ETHER_ADDR_LEN];<br> + int len;<br> +<br> + /* Firstly try "mac-address" */<br> + len = OF_getprop(node, "mac-address", tmp, sizeof(tmp));<br> + if (len == ETHER_ADDR_LEN && !ETHER_IS_ZERO(tmp) &&<br> + !ETHER_IS_MULTICAST(tmp)) {<br> + bcopy(tmp, eaddr, ETHER_ADDR_LEN);<br> + return;<br> + }<br> +<br> + /* Next use "local-mac-address" */<br> + len = OF_getprop(node, "local-mac-address", tmp, sizeof(tmp));<br> + if (len == ETHER_ADDR_LEN && !ETHER_IS_ZERO(tmp) &&<br> + !ETHER_IS_MULTICAST(tmp)) {<br> + bcopy(tmp, eaddr, ETHER_ADDR_LEN);<br> + return;<br> + }<br> +<br> + /* Next use existing one if set */<br> + if (!ETHER_IS_ZERO(eaddr) && !ETHER_IS_MULTICAST(eaddr))<br> + return;<br> +<br> + /* Last resort - generate random one */<br> + ether_gen_addr(ifp, (struct ether_addr *)eaddr);<br> +<br> + return;<br> +}<br> diff --git a/sys/dev/fdt/fdt_common.h b/sys/dev/fdt/fdt_common.h<br> index f597233f9771..3eee6913ad72 100644<br> --- a/sys/dev/fdt/fdt_common.h<br> +++ b/sys/dev/fdt/fdt_common.h<br> @@ -33,8 +33,11 @@<br> <br> #include <sys/sysctl.h><br> #include <sys/slicer.h><br> +#include <sys/socket.h><br> #include <contrib/libfdt/libfdt_env.h><br> #include <dev/ofw/ofw_bus.h><br> +#include <net/ethernet.h><br> +#include <net/if.h><br> <br> #define FDT_MEM_REGIONS 64<br> <br> @@ -70,6 +73,7 @@ typedef void (*fdt_mem_region_cb)(const struct mem_region *, void *);<br> int fdt_addrsize_cells(phandle_t, int *, int *);<br> u_long fdt_data_get(const void *, int);<br> int fdt_data_to_res(const pcell_t *, int, int, u_long *, u_long *);<br> +void fdt_ether_get_addr(phandle_t node, struct ifnet *ifp, uint8_t *eaddr);<br> phandle_t fdt_find_compatible(phandle_t, const char *, int);<br> phandle_t fdt_depth_search_compatible(phandle_t, const char *, int);<br> int fdt_foreach_mem_region(fdt_mem_region_cb, void *);<br> </div> <hr></div> </blockquote> <br> </body></html>home | help
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