From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: passt.top; dmarc=fail (p=quarantine dis=none) header.from=redhat.com Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by passt.top (Postfix) with ESMTPS id 4E7125A0265 for ; Mon, 26 Oct 2026 12:18:28 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1793013507; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=tJWk/+Hzl9zLodllyYTiWi2GxgyockGS3EDGH3G4d1Y=; b=fpNgXIiNzvupL3y6dbwh3CP+3pgtcck5DZumRqqIizNSOE+jPGDTr8/iXawNAkzchbRMwr Sav6oBeOXUMPQu6zPtPNl4STRp4KgAa2ulKWAgZq2WA/H7S1AZY97M4SkcGvr3kK8SL9iF aKfuhmncIVbq1iEMRY5hrKpnoxhOwnI= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-690-k54suE2VMhOglMofPS23jQ-1; Mon, 26 Oct 2026 07:18:26 -0400 X-MC-Unique: k54suE2VMhOglMofPS23jQ-1 X-Mimecast-MFC-AGG-ID: k54suE2VMhOglMofPS23jQ_1793013505 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 47EDD1800593 for ; Mon, 26 Oct 2026 11:18:25 +0000 (UTC) Received: from anskuma-thinkpadp1gen7.bengluru.csb (unknown [10.74.80.94]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id B600C1956089; Mon, 26 Oct 2026 11:18:23 +0000 (UTC) From: Anshu Kumari To: passt-dev@passt.top, sbrivio@redhat.com Subject: [PATCH v2] tcp: Avoid division by zero with small MSS values Date: Mon, 26 Oct 2026 16:48:20 +0530 Message-ID: <20261026111820.1600260-1-anskuma@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: DcL-MqjoYDcSiO60aYrixGdYb6sQFyQ4FSod61wwyv8_1793013505 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Message-ID-Hash: 5ENT456JKRY63E62SLWL4Y6XACDZ6TXX X-Message-ID-Hash: 5ENT456JKRY63E62SLWL4Y6XACDZ6TXX X-MailFrom: anskuma@redhat.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: anskuma@redhat.com X-Mailman-Version: 3.3.8 Precedence: list List-Id: Development discussion and patches for passt Archived-At: Archived-At: List-Archive: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: RnV6eiB0ZXN0aW5nIHdpdGggQUZMKysgcGVyc2lzdGVudCBtb2RlIGZvdW5kIHRoYXQNCnRjcF9i dWZfZGF0YV9mcm9tX3NvY2soKSB0ZXJtaW5hdGVzIHRoZSBwcm9jZXNzIHdpdGggU0lHRlBFDQoo c2lnbmFsIDgpIGZyb20gZGl2aXNpb24gYnkgemVybyBhdDoNCg0KICBmaWxsX2J1ZnMgPSBESVZf Uk9VTkRfVVAod25kX3NjYWxlZCAtIGFscmVhZHlfc2VudCwgbXNzKTsNCg0Kd2hlbiBNU1MgaXMg c21hbGwgZW5vdWdoIChsZXNzIHRoYW4gZm91cikgdG8gcm91bmQgZG93biB0byAwDQpkdXJpbmcg dGhlIGJpdC1zaGlmdCBpbiBNU1NfU0VUKCkuIFRoZSB0ZXJtaW5hdGlvbiBpdHNlbGYgaXMNCmNs ZWFuIChub3QgbWVtb3J5IGNvcnJ1cHRpb24gb3IgZGF0YSBsZWFrYWdlKSwgYnV0IHdlIGNhbg0K aGFuZGxlIHRoaXMgY29uZGl0aW9uIG1vcmUgZ3JhY2VmdWxseS4NCg0KV2UgY29uc2lkZXJlZCBy ZXNldHRpbmcgY29ubmVjdGlvbnMgd2l0aCBhIHplcm8gb3IgdmVyeSBsb3cNCk1TUywgYnV0IGNv bmNsdWRlZCB0aGlzIGlzIG5vdCBSRkMtY29tcGxpYW50OiBSRkMgOTI5MywNCnNlY3Rpb24gMy4x IChNVVNULTcpLCBzdGF0ZXM6ICJUQ1AgaW1wbGVtZW50YXRpb25zIE1VU1QgYmUNCnByZXBhcmVk IHRvIGhhbmRsZSBhbiBpbGxlZ2FsIG9wdGlvbiBsZW5ndGggKGUuZy4sIHplcm8pOyBhDQpzdWdn ZXN0ZWQgcHJvY2VkdXJlIGlzIHRvIHJlc2V0IHRoZSBjb25uZWN0aW9uIGFuZCBsb2cgdGhlDQpl cnJvciBjYXVzZS4iIEhvd2V2ZXIsIHRoaXMgYXBwbGllcyBvbmx5IHRvIG9wdGlvbiAqbGVuZ3Ro cyosDQpub3QgKnZhbHVlcyog4oCUIG5vIHN0YW5kYXJkIFJGQyBkZWZpbmVzIGEgbWluaW11bSBN U1MgdmFsdWUuDQpTZWN0aW9uIDMuNS4yIGZ1cnRoZXIgc3RhdGVzOiAiQSByZXNldCBtdXN0IG5v dCBiZSBzZW50IGlmDQppdCBpcyBub3QgY2xlYXIgdGhhdCB0aGlzIGlzIHRoZSBjYXNlLiIgVmVy eSBsb3cgTVNTIHZhbHVlcw0KYWxzbyBoYXZlIGxlZ2l0aW1hdGUgdXNlcyBpbiBtaWNyb2NvbnRy b2xsZXIgYXBwbGljYXRpb25zDQp3aXRoIGxpbWl0ZWQgYnVmZmVycywgYW5kIGEgemVybyBNU1Mg Y291bGQgcmVwcmVzZW50IGENCnVuaWRpcmVjdGlvbmFsIGNvbm5lY3Rpb24uDQoNClJvdW5kaW5n IGEgbG93IE1TUyB1cHdhcmQgaXMgYWxzbyBub3QgYW4gb3B0aW9uOiBlbWl0dGluZw0Kc2VnbWVu dHMgbGFyZ2VyIHRoYW4gdGhlIHBlZXIgYWR2ZXJ0aXNlZCB2aW9sYXRlcyB0aGUNCmVmZmVjdGl2 ZSBzZW5kIE1TUyByZXF1aXJlbWVudCBpbiBSRkMgOTI5Mywgc2VjdGlvbiAzLjcuMS4NCg0KSW5z dGVhZCwgcHJlc2VydmUgdGhlIGFjdHVhbCBNU1M6DQoNCiAgLSBBZGp1c3QgTVNTX1NFVCgpIHRv IGNsYW1wIG5vbi16ZXJvIHZhbHVlcyBiZWxvdyA0IHRvIDEsDQogICAgYXZvaWRpbmcgdGhlIHJv dW5kLXRvLXplcm8gaW4gYml0LWZpZWxkIHN0b3JhZ2UuDQogIC0gQWRqdXN0IE1TU19HRVQoKSB0 byByZXR1cm4gMSB3aGVuIHRhcF9tc3MgaXMgMSwgc28gd2UNCiAgICBuZXZlciBpbmZsYXRlIHRo ZSBNU1MgYmV5b25kIHdoYXQgdGhlIHBlZXIgYWR2ZXJ0aXNlZC4NCiAgLSBXaGVuIE1TUyBpcyB6 ZXJvLCBkb24ndCBzZW5kIGRhdGE6DQogICAgdGNwX2J1Zl9kYXRhX2Zyb21fc29jaygpIHJldHVy bnMgZWFybHkuIFRoZSBwZWVyIHdpbGwNCiAgICBldmVudHVhbGx5IGRldGVybWluZSB0aGUgY29u bmVjdGlvbiBpcyB1bnVzYWJsZSBhbmQNCiAgICByZXNldCBpdC4NCg0KU2lnbmVkLW9mZi1ieTog QW5zaHUgS3VtYXJpIDxhbnNrdW1hQHJlZGhhdC5jb20+DQotLS0NCnYyOg0KICAtIGFkZGVkIGNv bW1lbnQgZm9yIGJvdGggTVNTX1NFVCgpIGFuZCBNU1NfR0VUKCkgbWFjcm8uDQogIC0gZml4ZWQv bW9kaWZpZWQgTVNTX0dFVCgpLg0KICAtIGZpeGVkIGNvbW1pdCBtZXNzYWdlIGJ5IGV4cGxhaW5p bmcgd2h5IHdlIGFyZSBub3QNCiAgICByZXNldHRpbmcgdGhlIGNvbm5lY3Rpb24uDQoNCk5PVEU6 IGxldCB0aGUgZnV6emVyIHJ1biBmb3IgbW9yZSB0aGFuIGEgZGF5IHdpdGggdGhpcw0KICAgICAg Zml4IGJ1dCB0aWxsIG5vdywgaGF2ZW4ndCBmb3VuZCBhbnkgaXNzdWUuDQotLS0NCiB0Y3BfYnVm LmMgIHwgIDMgKysrDQogdGNwX2Nvbm4uaCB8IDEwICsrKysrKysrLS0NCiAyIGZpbGVzIGNoYW5n ZWQsIDExIGluc2VydGlvbnMoKyksIDIgZGVsZXRpb25zKC0pDQoNCmRpZmYgLS1naXQgYS90Y3Bf YnVmLmMgYi90Y3BfYnVmLmMNCmluZGV4IDcyYzQ1NDEyLi5lZThjN2NlOCAxMDA2NDQNCi0tLSBh L3RjcF9idWYuYw0KKysrIGIvdGNwX2J1Zi5jDQpAQCAtMzM1LDYgKzMzNSw5IEBAIGludCB0Y3Bf YnVmX2RhdGFfZnJvbV9zb2NrKGNvbnN0IHN0cnVjdCBjdHggKmMsIHN0cnVjdCB0Y3BfdGFwX2Nv bm4gKmNvbm4sDQogCXN0cnVjdCBpb3ZlYyAqaW92Ow0KIAl1aW50MzJfdCBzZXE7DQogDQorCWlm ICghbXNzKQ0KKwkJcmV0dXJuIDA7DQorDQogCS8qIFNldCB1cCBidWZmZXIgZGVzY3JpcHRvcnMg d2UnbGwgZmlsbCBjb21wbGV0ZWx5IGFuZCBwYXJ0aWFsbHkuICovDQogCWZpbGxfYnVmcyA9IERJ Vl9ST1VORF9VUCh3bmRfc2NhbGVkIC0gYWxyZWFkeV9zZW50LCBtc3MpOw0KIAlpZiAoZmlsbF9i dWZzID4gVENQX0ZSQU1FUykgew0KZGlmZiAtLWdpdCBhL3RjcF9jb25uLmggYi90Y3BfY29ubi5o DQppbmRleCBlM2M1NTM0MS4uMzE3M2RkYjkgMTAwNjQ0DQotLS0gYS90Y3BfY29ubi5oDQorKysg Yi90Y3BfY29ubi5oDQpAQCAtNTEsOCArNTEsMTQgQEAgc3RydWN0IHRjcF90YXBfY29ubiB7DQog DQogI2RlZmluZSBUQ1BfTVNTX0JJVFMJCQkxNA0KIAl1bnNpZ25lZCBpbnQJdGFwX21zcwkJOlRD UF9NU1NfQklUUzsNCi0jZGVmaW5lIE1TU19TRVQoY29ubiwgbXNzKQkoY29ubi0+dGFwX21zcyA9 IChtc3MgPj4gKDE2IC0gVENQX01TU19CSVRTKSkpDQotI2RlZmluZSBNU1NfR0VUKGNvbm4pCQko Y29ubi0+dGFwX21zcyA8PCAoMTYgLSBUQ1BfTVNTX0JJVFMpKQ0KKw0KKwkvKiBDbGFtcCBub24t emVybyBNU1MgPCA0IHRvIDEgdG8gYXZvaWQgcm91bmRpbmcgdG8gemVybyAqLw0KKyNkZWZpbmUg TVNTX1NFVChjb25uLCBtc3MpCQkJCQkJXA0KKwkoY29ubi0+dGFwX21zcyA9IChtc3MpID8gTUFY KDEsIChtc3MpID4+ICgxNiAtIFRDUF9NU1NfQklUUykpIDogMCkNCisNCisJLyogdGFwX21zcyBp cyBzdG9yZWQgYXMgMSBmb3IgYW55IG5vbi16ZXJvIE1TUyB2YWx1ZSA8PSA0ICovDQorI2RlZmlu ZSBNU1NfR0VUKGNvbm4pCQkJCQkJCVwNCisJKChjb25uLT50YXBfbXNzID09IDEpID8gMSA6IChj b25uLT50YXBfbXNzIDw8ICgxNiAtIFRDUF9NU1NfQklUUykpKQ0KIA0KICNkZWZpbmUgUlRUX0VY UF9CSVRTCQkJNA0KIAl1bnNpZ25lZCBpbnQJcnR0X2V4cAkJOlJUVF9FWFBfQklUUzsNCi0tIA0K Mi41NS4wDQoNCg==