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Fri, 17 May 2019 08:57:40 -0400 Received: from AcuMS.aculab.com (156.67.243.126 [156.67.243.126]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-101-g0dBW_K3ORqRsV6sBecm3g-1; Fri, 17 May 2019 13:57:37 +0100 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b::d117) by AcuMS.aculab.com (fd9f:af1c:a25b::d117) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Fri, 17 May 2019 13:57:37 +0100 Received: from AcuMS.Aculab.com ([fe80::43c:695e:880f:8750]) by AcuMS.aculab.com ([fe80::43c:695e:880f:8750%12]) with mapi id 15.00.1347.000; Fri, 17 May 2019 13:57:37 +0100 From: David Laight To: 'Willem de Bruijn' , Adam Urban CC: Eric Dumazet , Network Development Subject: RE: Kernel UDP behavior with missing destinations Thread-Topic: Kernel UDP behavior with missing destinations Thread-Index: AQHVDF/dVLHMBGRH2UCXYs4ZosL7YqZvHIew Date: Fri, 17 May 2019 12:57:36 +0000 Message-ID: <655000834f584886ae87f5d8836837ba@AcuMS.aculab.com> References: <0d50023e-0a3b-b92b-59d6-39d0c02fa182@gmail.com> In-Reply-To: Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 X-MC-Unique: g0dBW_K3ORqRsV6sBecm3g-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: base64 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org RnJvbTogV2lsbGVtIGRlIEJydWlqbg0KPiBTZW50OiAxNyBNYXkgMjAxOSAwNDoyMw0KPiBPbiBU aHUsIE1heSAxNiwgMjAxOSBhdCA4OjI3IFBNIEFkYW0gVXJiYW4gPGFkYW0udXJiYW5AYXBwbGVn dXJ1Lm9yZz4gd3JvdGU6DQo+ID4NCj4gPiBBbmQgcmVwbHlpbmcgdG8geW91ciBlYXJsaWVyIGNv bW1lbnQgYWJvdXQgVFRMLCB5ZXMgSSB0aGluayBhIFRUTCBvbg0KPiA+IGFycF9xdWV1ZXMgd291 bGQgYmUgaHVnZWx5IGhlbHBmdWwuDQo+ID4NCj4gPiBJbiBhbnkgZW52aXJvbm1lbnQgd2hlcmUg eW91IGFyZSBzdHJlYW1pbmcgdGltZS1zZW5zaXRpdmUgVURQIHRyYWZmaWMsDQo+ID4geW91IHJl YWxseSB3YW50IHRoZSBrZXJuZWwgdG8gYmUgdHVuZWQgdG8gaW1tZWRpYXRlbHkgZHJvcCB0aGUN Cj4gPiBvdXRnb2luZyBwYWNrZXQgaWYgdGhlIGRlc3RpbmF0aW9uIGlzbid0IHlldCBrbm93bi9p biB0aGUgYXJwIHRhYmxlDQo+ID4gYWxyZWFkeS4uLg0KDQpJIHN1c3BlY3Qgd2UgbWF5IHN1ZmZl ciBmcm9tIHRoZSBzYW1lIHByb2JsZW1zIHdoZW4gc2VuZGluZyBvdXQgYSBsb3QNCm9mIFJUUCAo dGhpbmsgb2Ygc2VuZGluZyAxMDAwcyBvZiBVRFAgbWVzc2FnZXMgdG8gZGlmZmVyZW50IGFkZHJl c3Nlcw0KZXZlcnkgMjBtcykuDQpGb3IgdmFyaW91cyByZWFzb25zIHRoZSBzZW5kcyBhcmUgZG9u ZSBmcm9tIGEgc2luZ2xlIHJhdyBzb2NrZXQgKHJhdGhlcg0KdGhhbiAnY29ubmVjdGVkJyBVRFAg c29ja2V0cykuDQoNCj4gRm9yIHBhY2tldHMgdGhhdCBuZWVkIHRvIGJlIHNlbnQgaW1tZWRpYXRl bHkgb3Igbm90IGF0IGFsbCwgeW91DQo+IHByb2JhYmx5IGRvIG5vdCB3YW50IGEgVFRMLCBidXQg c2ltcGx5IGZvciB0aGUgc2VuZCBjYWxsIHRvIGZhaWwNCj4gaW1tZWRpYXRlbHkgd2l0aCBFQUdB SU4gaW5zdGVhZCBvZiBxdWV1aW5nIHRoZSBwYWNrZXQgZm9yIEFSUA0KPiByZXNvbHV0aW9uIGF0 IGFsbC4gV2hpY2ggaXMgYXBwcm94aW1hdGVkIHdpdGggdW5yZXNfcWxlbiAwLg0KPiANCj4gVGhl IHJlbGF0aW9uIGJldHdlZW4gdW5yZXNfcWxlbl9ieXRlcywgYXJwX3F1ZXVlIGFuZCBTT19TTkRC VUYgaXMNCj4gcHJldHR5IHN0cmFpZ2h0Zm9yd2FyZCBpbiBwcmluY2lwYWwuIFBhY2tldHMgY2Fu IGJlIHF1ZXVlZCBvbiB0aGUgYXJwDQo+IHF1ZXVlIHVudGlsIHRoZSBieXRlIGxpbWl0IGlzIHJl YWNoZWQuIEFueSBwYWNrZXRzIG9uIHRoaXMgcXVldWUgc3RpbGwNCj4gaGF2ZSB0aGVpciBtZW1v cnkgY291bnRlZCB0b3dhcmRzIHRoZWlyIHNvY2tldCBzZW5kIGJ1ZGdldC4gSWYgYQ0KPiBwYWNr ZXQgaXMgcXVldWVkIHRoYXQgY2F1c2VzIHRvIGV4Y2VlZCB0aGUgdGhyZXNob2xkLCBvbGRlciBw YWNrZXRzDQo+IGFyZSBmcmVlZCBhbmQgZHJvcHBlZCBhcyBuZWVkZWQuIENhbGN1bGF0aW5nIHRo ZSBleGFjdCBudW1iZXJzIGlzIG5vdA0KPiBhcyBzdHJhaWdodGZvcndhcmQsIGFzLCBmb3IgaW5z dGFuY2UsIHNrYi0+dHJ1ZXNpemUgaXMgYSBrZXJuZWwNCj4gaW1wbGVtZW50YXRpb24gZGV0YWls Lg0KDQpCdXQgJ2ZpZGRsaW5nJyB3aXRoIHRoZSBhcnAgcXVldWUgd2lsbCBhZmZlY3QgYWxsIHRy YWZmaWMuDQpTbyB5b3UnZCBuZWVkIGl0IHRvIGJlIHBlciBzb2NrZXQgb3B0aW9uIHNvIHRoYXQg aXQgaXMgYSBwcm9wZXJ0eQ0Kb2YgdGhlIG1lc3NhZ2UgYnkgdGhlIHRpbWUgaXQgcmVhY2hlcyB0 aGUgYXJwIGNvZGUuDQoNCj4gVGhlIHNpbXBsZSBzb2x1dGlvbiBpcyBqdXN0IHRvIG92ZXJwcm92 aXNpb24gdGhlIHNvY2tldCBTT19TTkRCVUYuIElmDQo+IHRoZXJlIGFyZSBmZXcgc29ja2V0cyBp biB0aGUgc3lzdGVtIHRoYXQgcGVyZm9ybSB0aGlzIHJvbGUsIHRoYXQgc2VlbXMNCj4gcGVyZmVj dGx5IGZpbmUuDQoNClRoYXQgZGVwZW5kcyBvbiBob3cgb2Z0ZW4geW91IGFyZSBzZW5kaW5nIG1l c3NhZ2VzIGNvbXBhcmVkIHRvIHRoZQ0KYXJwIHRpbWVvdXQuIElmIHlvdSBhcmUgc2VuZGluZyA1 MCBtZXNzYWdlcyBhIHNlY29uZCB0byBlYWNoIG9mIDEwMDANCmRlc3RpbmF0aW9ucyB0aGUgb3Zl ciBwcm92aXNpb25pbmcgb2YgU09fU05EQlVGIHdvdWxkIGhhdmUgdG8gYmUgZXh0cmVtZS4NCg0K RldJVyB3ZSBkbyBzb21ldGltZXMgc2VlIHNlbmRtc2coKSB0YWtpbmcgbXVjaCBsb25nZXIgdGhh biBleHBlY3RlZCwNCmJ1dCBoYXZlbid0IGdldCB0cmFja2VkIGRvd24gd2h5Lg0KDQoJRGF2aWQN Cg0KLQ0KUmVnaXN0ZXJlZCBBZGRyZXNzIExha2VzaWRlLCBCcmFtbGV5IFJvYWQsIE1vdW50IEZh cm0sIE1pbHRvbiBLZXluZXMsIE1LMSAxUFQsIFVLDQpSZWdpc3RyYXRpb24gTm86IDEzOTczODYg KFdhbGVzKQ0K