From mboxrd@z Thu Jan 1 00:00:00 1970 From: russell@personaltelco.net (Russell Senior) Date: Sun, 10 Jul 2016 00:19:43 -0700 Subject: [LEDE-DEV] DHCP via bridge in case of IPv4 In-Reply-To: <1468065830.5007.10.camel@synopsys.com> (Alexey Brodkin's message of "Sat, 9 Jul 2016 12:05:07 +0000") References: <1468053400.5007.5.camel@synopsys.com> <1468065830.5007.10.camel@synopsys.com> List-ID: Message-ID: <87shviklio.fsf@husum.klickitat.com> To: linux-snps-arc@lists.infradead.org >>>>> "Alexey" == Alexey Brodkin writes: Alexey> Hi Aaron, Alexey> On Sat, 2016-07-09@07:47 -0400, Aaron Z wrote: >> On Sat, Jul 9, 2016 at 4:37 AM, Alexey Brodkin >> wrote: >> > >> > Hello, >> > >> > I was playing with quite simple bridged setup on different boards >> with > very recent kernels (4.6.3 as of this writing) and found one >> interesting > behavior that I cannot yet understand and googling >> din't help here as well. >> > >> > My setup is pretty simple: > >> -------------???????------------------???????------------------------- >> > > >> > > HOST??????|???????| "Dumb AP"??????|???????| Wireless >> client???????| > > with DHCP |<----->(eth0)?????(wlan0)<----->| >> attempting to?????????| > > server????|???????|????\ br0 >> /?????|???????| get settings via DHCP | > >> -------------???????------------------???????------------------------- >> > >> > * HOST is my laptop with DHCP server that works for sure. > * >> "Dumb AP" is a separate board (I tried ARM-based Wandboard and >> ARC-based > ? AXS10x boards but results are exactly the same) with >> wired (eth0) and wireless > ? (wlan0) network controllers bridged >> together (br0). That "br0" bridge flawlessly > ? gets its settings >> from DHCP server on host. > * Wireless client could be either a >> smatrphone or another laptop etc but > ? what's important it should >> be configured to get network settings by DHCP as well. >> > >> > So what happens "br0" always gets network settings from DHCP server >> on HOST. > That's fine. But wireless client only reliably gets >> settings from DHCP server > if IPv6 is enabled on "Dumb AP" board. If >> IPv6 is disabled I may see that > wireless client sends "DHCP >> Discover" then server replies with "DHCP Offer" but > that offer >> never reaches wireless client. >> >> >> Do you have WDS enabled? If not, DHCP has issues in that scenario: >> https://wiki.openwrt.org/doc/howto/clientmode If the Dumb AP's wireless interface is in ap-mode, then this shouldn't be an issue. It's only client-mode interfaces that have trouble with bridging. I'd suggest running tcpdump on the Dumb AP's wireless interface and the client's wireless interface and see which of them sees the various parts of the DHCP handshake. -- Russell Senior, President russell at personaltelco.net From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752750AbcGJH0a (ORCPT ); Sun, 10 Jul 2016 03:26:30 -0400 Received: from mail.tdb.com ([64.184.245.180]:54779 "HELO mail.tdb.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1750761AbcGJH02 convert rfc822-to-8bit (ORCPT ); Sun, 10 Jul 2016 03:26:28 -0400 X-Greylist: delayed 401 seconds by postgrey-1.27 at vger.kernel.org; Sun, 10 Jul 2016 03:26:28 EDT From: Russell Senior To: Alexey Brodkin Cc: "aczlan+ledev\@gmail.com" , "netdev\@vger.kernel.org" , "lede-dev\@lists.infradead.org" , "davem\@davemloft.net" , "linux-snps-arc\@lists.infradead.org" , "linux-kernel\@vger.kernel.org" Subject: Re: [LEDE-DEV] DHCP via bridge in case of IPv4 References: <1468053400.5007.5.camel@synopsys.com> <1468065830.5007.10.camel@synopsys.com> Date: Sun, 10 Jul 2016 00:19:43 -0700 In-Reply-To: <1468065830.5007.10.camel@synopsys.com> (Alexey Brodkin's message of "Sat, 9 Jul 2016 12:05:07 +0000") Message-ID: <87shviklio.fsf@husum.klickitat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>>>> "Alexey" == Alexey Brodkin writes: Alexey> Hi Aaron, Alexey> On Sat, 2016-07-09 at 07:47 -0400, Aaron Z wrote: >> On Sat, Jul 9, 2016 at 4:37 AM, Alexey Brodkin >> wrote: >> > >> > Hello, >> > >> > I was playing with quite simple bridged setup on different boards >> with > very recent kernels (4.6.3 as of this writing) and found one >> interesting > behavior that I cannot yet understand and googling >> din't help here as well. >> > >> > My setup is pretty simple: > >> -------------       ------------------       ------------------------- >> > > >> > > HOST      |       | "Dumb AP"      |       | Wireless >> client       | > > with DHCP |<----->(eth0)     (wlan0)<----->| >> attempting to         | > > server    |       |    \ br0 >> /     |       | get settings via DHCP | > >> -------------       ------------------       ------------------------- >> > >> > * HOST is my laptop with DHCP server that works for sure. > * >> "Dumb AP" is a separate board (I tried ARM-based Wandboard and >> ARC-based >   AXS10x boards but results are exactly the same) with >> wired (eth0) and wireless >   (wlan0) network controllers bridged >> together (br0). That "br0" bridge flawlessly >   gets its settings >> from DHCP server on host. > * Wireless client could be either a >> smatrphone or another laptop etc but >   what's important it should >> be configured to get network settings by DHCP as well. >> > >> > So what happens "br0" always gets network settings from DHCP server >> on HOST. > That's fine. But wireless client only reliably gets >> settings from DHCP server > if IPv6 is enabled on "Dumb AP" board. If >> IPv6 is disabled I may see that > wireless client sends "DHCP >> Discover" then server replies with "DHCP Offer" but > that offer >> never reaches wireless client. >> >> >> Do you have WDS enabled? If not, DHCP has issues in that scenario: >> https://wiki.openwrt.org/doc/howto/clientmode If the Dumb AP's wireless interface is in ap-mode, then this shouldn't be an issue. It's only client-mode interfaces that have trouble with bridging. I'd suggest running tcpdump on the Dumb AP's wireless interface and the client's wireless interface and see which of them sees the various parts of the DHCP handshake. -- Russell Senior, President russell@personaltelco.net From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell Senior Subject: Re: [LEDE-DEV] DHCP via bridge in case of IPv4 Date: Sun, 10 Jul 2016 00:19:43 -0700 Message-ID: <87shviklio.fsf@husum.klickitat.com> References: <1468053400.5007.5.camel@synopsys.com> <1468065830.5007.10.camel@synopsys.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Cc: "netdev@vger.kernel.org" , "lede-dev@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "aczlan+ledev@gmail.com" , "linux-snps-arc@lists.infradead.org" , "davem@davemloft.net" To: Alexey Brodkin Return-path: In-Reply-To: <1468065830.5007.10.camel@synopsys.com> (Alexey Brodkin's message of "Sat, 9 Jul 2016 12:05:07 +0000") List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-snps-arc" Errors-To: linux-snps-arc-bounces+gla-linux-snps-arc=m.gmane.org@lists.infradead.org List-Id: netdev.vger.kernel.org Pj4+Pj4gIkFsZXhleSIgPT0gQWxleGV5IEJyb2RraW4gPEFsZXhleS5Ccm9ka2luQHN5bm9wc3lz LmNvbT4gd3JpdGVzOgoKQWxleGV5PiBIaSBBYXJvbiwKQWxleGV5PiBPbiBTYXQsIDIwMTYtMDct MDkgYXQgMDc6NDcgLTA0MDAsIEFhcm9uIFogd3JvdGU6Cj4+IE9uIFNhdCwgSnVsIDksIDIwMTYg YXQgNDozNyBBTSwgQWxleGV5IEJyb2RraW4KPj4gPEFsZXhleS5Ccm9ka2luQHN5bm9wc3lzLmNv bT4gd3JvdGU6Cj4+ID4gCj4+ID4gSGVsbG8sCj4+ID4gCj4+ID4gSSB3YXMgcGxheWluZyB3aXRo IHF1aXRlIHNpbXBsZSBicmlkZ2VkIHNldHVwIG9uIGRpZmZlcmVudCBib2FyZHMKPj4gd2l0aCA+ IHZlcnkgcmVjZW50IGtlcm5lbHMgKDQuNi4zIGFzIG9mIHRoaXMgd3JpdGluZykgYW5kIGZvdW5k IG9uZQo+PiBpbnRlcmVzdGluZyA+IGJlaGF2aW9yIHRoYXQgSSBjYW5ub3QgeWV0IHVuZGVyc3Rh bmQgYW5kIGdvb2dsaW5nCj4+IGRpbid0IGhlbHAgaGVyZSBhcyB3ZWxsLgo+PiA+IAo+PiA+IE15 IHNldHVwIGlzIHByZXR0eSBzaW1wbGU6ID4KPj4gLS0tLS0tLS0tLS0tLcKgwqDCoMKgwqDCoMKg LS0tLS0tLS0tLS0tLS0tLS0twqDCoMKgwqDCoMKgwqAtLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0t Cj4+ID4gPiAKPj4gPiA+IEhPU1TCoMKgwqDCoMKgwqB8wqDCoMKgwqDCoMKgwqB8ICJEdW1iIEFQ IsKgwqDCoMKgwqDCoHzCoMKgwqDCoMKgwqDCoHwgV2lyZWxlc3MKPj4gY2xpZW50wqDCoMKgwqDC oMKgwqB8ID4gPiB3aXRoIERIQ1AgfDwtLS0tLT4oZXRoMCnCoMKgwqDCoMKgKHdsYW4wKTwtLS0t LT58Cj4+IGF0dGVtcHRpbmcgdG/CoMKgwqDCoMKgwqDCoMKgwqB8ID4gPiBzZXJ2ZXLCoMKgwqDC oHzCoMKgwqDCoMKgwqDCoHzCoMKgwqDCoFwgYnIwCj4+IC/CoMKgwqDCoMKgfMKgwqDCoMKgwqDC oMKgfCBnZXQgc2V0dGluZ3MgdmlhIERIQ1AgfCA+Cj4+IC0tLS0tLS0tLS0tLS3CoMKgwqDCoMKg wqDCoC0tLS0tLS0tLS0tLS0tLS0tLcKgwqDCoMKgwqDCoMKgLS0tLS0tLS0tLS0tLS0tLS0tLS0t LS0tLQo+PiA+IAo+PiA+ICogSE9TVCBpcyBteSBsYXB0b3Agd2l0aCBESENQIHNlcnZlciB0aGF0 IHdvcmtzIGZvciBzdXJlLiAgPiAqCj4+ICJEdW1iIEFQIiBpcyBhIHNlcGFyYXRlIGJvYXJkIChJ IHRyaWVkIEFSTS1iYXNlZCBXYW5kYm9hcmQgYW5kCj4+IEFSQy1iYXNlZCA+IMKgIEFYUzEweCBi b2FyZHMgYnV0IHJlc3VsdHMgYXJlIGV4YWN0bHkgdGhlIHNhbWUpIHdpdGgKPj4gd2lyZWQgKGV0 aDApIGFuZCB3aXJlbGVzcyA+IMKgICh3bGFuMCkgbmV0d29yayBjb250cm9sbGVycyBicmlkZ2Vk Cj4+IHRvZ2V0aGVyIChicjApLiBUaGF0ICJicjAiIGJyaWRnZSBmbGF3bGVzc2x5ID4gwqAgZ2V0 cyBpdHMgc2V0dGluZ3MKPj4gZnJvbSBESENQIHNlcnZlciBvbiBob3N0LiAgPiAqIFdpcmVsZXNz IGNsaWVudCBjb3VsZCBiZSBlaXRoZXIgYQo+PiBzbWF0cnBob25lIG9yIGFub3RoZXIgbGFwdG9w IGV0YyBidXQgPiDCoCB3aGF0J3MgaW1wb3J0YW50IGl0IHNob3VsZAo+PiBiZSBjb25maWd1cmVk IHRvIGdldCBuZXR3b3JrIHNldHRpbmdzIGJ5IERIQ1AgYXMgd2VsbC4KPj4gPiAKPj4gPiBTbyB3 aGF0IGhhcHBlbnMgImJyMCIgYWx3YXlzIGdldHMgbmV0d29yayBzZXR0aW5ncyBmcm9tIERIQ1Ag c2VydmVyCj4+IG9uIEhPU1QuICA+IFRoYXQncyBmaW5lLiBCdXQgd2lyZWxlc3MgY2xpZW50IG9u bHkgcmVsaWFibHkgZ2V0cwo+PiBzZXR0aW5ncyBmcm9tIERIQ1Agc2VydmVyID4gaWYgSVB2NiBp cyBlbmFibGVkIG9uICJEdW1iIEFQIiBib2FyZC4gSWYKPj4gSVB2NiBpcyBkaXNhYmxlZCBJIG1h eSBzZWUgdGhhdCA+IHdpcmVsZXNzIGNsaWVudCBzZW5kcyAiREhDUAo+PiBEaXNjb3ZlciIgdGhl biBzZXJ2ZXIgcmVwbGllcyB3aXRoICJESENQIE9mZmVyIiBidXQgPiB0aGF0IG9mZmVyCj4+IG5l dmVyIHJlYWNoZXMgd2lyZWxlc3MgY2xpZW50Lgo+PiAKPj4gCj4+IERvIHlvdSBoYXZlIFdEUyBl bmFibGVkPyBJZiBub3QsIERIQ1AgaGFzIGlzc3VlcyBpbiB0aGF0IHNjZW5hcmlvOgo+PiBodHRw czovL3dpa2kub3BlbndydC5vcmcvZG9jL2hvd3RvL2NsaWVudG1vZGUKCklmIHRoZSBEdW1iIEFQ J3Mgd2lyZWxlc3MgaW50ZXJmYWNlIGlzIGluIGFwLW1vZGUsIHRoZW4gdGhpcyBzaG91bGRuJ3QK YmUgYW4gaXNzdWUuICBJdCdzIG9ubHkgY2xpZW50LW1vZGUgaW50ZXJmYWNlcyB0aGF0IGhhdmUg dHJvdWJsZSB3aXRoIGJyaWRnaW5nLgoKSSdkIHN1Z2dlc3QgcnVubmluZyB0Y3BkdW1wIG9uIHRo ZSBEdW1iIEFQJ3Mgd2lyZWxlc3MgaW50ZXJmYWNlIGFuZCB0aGUKY2xpZW50J3Mgd2lyZWxlc3Mg aW50ZXJmYWNlIGFuZCBzZWUgd2hpY2ggb2YgdGhlbSBzZWVzIHRoZSB2YXJpb3VzIHBhcnRzCm9m IHRoZSBESENQIGhhbmRzaGFrZS4KCgotLSAKUnVzc2VsbCBTZW5pb3IsIFByZXNpZGVudApydXNz ZWxsQHBlcnNvbmFsdGVsY28ubmV0CgpfX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fXwpsaW51eC1zbnBzLWFyYyBtYWlsaW5nIGxpc3QKbGludXgtc25wcy1hcmNA bGlzdHMuaW5mcmFkZWFkLm9yZwpodHRwOi8vbGlzdHMuaW5mcmFkZWFkLm9yZy9tYWlsbWFuL2xp c3RpbmZvL2xpbnV4LXNucHMtYXJj