From patchwork Fri Aug 6 10:08:54 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 12423141 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5E12FC4320A for ; Fri, 6 Aug 2021 10:09:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 455546101C for ; Fri, 6 Aug 2021 10:09:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244925AbhHFKJU (ORCPT ); Fri, 6 Aug 2021 06:09:20 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:57670 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244905AbhHFKJQ (ORCPT ); Fri, 6 Aug 2021 06:09:16 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1628244540; 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=tDHQ9Ulm3F1gZvDZHi0UnxkFYVqUZuhtyF1seBl2e04=; b=hI0adXF8EColLVHDP6+tmaYddTKmY72NI0uP7bik1i4heEYHG7P0by2xSjrNPbA62S+x0K gxnnZrD0Fcdaejek9Le+Pp0EkJ2EbOVXo3A9t6ptWgjORWnqdyxz8UiyBS3ls6SsJss+xi QDHEINC+k0IYMyXDGZBuZ/JTByf8wTM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-592-fJyrQIvZNpemSWHwaQcnZg-1; Fri, 06 Aug 2021 06:08:58 -0400 X-MC-Unique: fJyrQIvZNpemSWHwaQcnZg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1A9C087180C; Fri, 6 Aug 2021 10:08:57 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.22.32.7]) by smtp.corp.redhat.com (Postfix) with ESMTP id 566597A8D7; Fri, 6 Aug 2021 10:08:55 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells To: Jeffrey E Altman , Marc Dionne cc: dhowells@redhat.com, Benjamin Kaduk , linux-afs@lists.infradead.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [RFC][PATCH] rxrpc: Support reception of extended-SACK ACK packet MIME-Version: 1.0 Content-ID: <1290707.1628244534.1@warthog.procyon.org.uk> Date: Fri, 06 Aug 2021 11:08:54 +0100 Message-ID: <1290708.1628244534@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org X-Patchwork-State: RFC The RxRPC ACK packet supports selective ACK of up to 255 DATA packets. It contains a variable length array with one octet allocated for each DATA packet to be ACK'd. Each octet is either 0 or 1 depending on whether it is a negative or positive ACK. 7 bits in each octet are effectively unused and, further, there are three reserved octets following the ACK array that are all set to 0. To extend the ACK window up to 2048 ACKs, it is proposed[1]: (1) that the ACKs for DATA packets first+0...first+254 in the Rx window are in bit 0 of the octets in the array, ie. acks[0...254], pretty much as now; and (2) that if the ACK count is >=256, the first reserved byte after the ACK table is annexed to the ACK table as acks[255] and contains the ACK for packet first+255 in bit 0; and (3) that if the ACK count is >256, horizontal striping be employed such that the ACK for packet first+256 in the window is then in bit 1 of acks[0], first+257 is in bit 1 of acks[1], up to first+511 being in bit 1 of the borrowed reserved byte (ie. acks[255]). first+512 is then in bit 2 of acks[0], going all the way up to first+2048 being in bit 7 of acks[255]. If extended SACK is employed in an ACK packet, it should have EXTENDED-SACK (0x08) set in the RxRPC packet header. Alter rxrpc_input_ack() to sanity check the ACK count. Alter rxrpc_input_ack() to limit the number of bytes it extracts from the packet for the ack array to 256. Alter rxrpc_input_soft_acks() to handle an extended SACK table. Signed-off-by: David Howells Link: https://gerrit.openafs.org/#/c/14693/3 [1] --- net/rxrpc/input.c | 21 ++++++++++++++------- net/rxrpc/protocol.h | 7 +++++-- 2 files changed, 19 insertions(+), 9 deletions(-) diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c index dc201363f2c4..0a7f7462b617 100644 --- a/net/rxrpc/input.c +++ b/net/rxrpc/input.c @@ -767,15 +767,17 @@ static void rxrpc_input_soft_acks(struct rxrpc_call *call, u8 *acks, rxrpc_seq_t seq, int nr_acks, struct rxrpc_ack_summary *summary) { - int ix; - u8 annotation, anno_type; + int ix, i; + u8 annotation, anno_type, ack; - for (; nr_acks > 0; nr_acks--, seq++) { + for (i = 0; i < nr_acks; i++, seq++) { ix = seq & RXRPC_RXTX_BUFF_MASK; annotation = call->rxtx_annotations[ix]; anno_type = annotation & RXRPC_TX_ANNO_MASK; annotation &= ~RXRPC_TX_ANNO_MASK; - switch (*acks++) { + ack = acks[i % RXRPC_EXTENDED_SACK_SIZE]; + ack >>= i / RXRPC_EXTENDED_SACK_SIZE; + switch (ack) { case RXRPC_ACK_TYPE_ACK: summary->nr_acks++; if (anno_type == RXRPC_TX_ANNO_ACK) @@ -846,7 +848,7 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb) union { struct rxrpc_ackpacket ack; struct rxrpc_ackinfo info; - u8 acks[RXRPC_MAXACKS]; + u8 acks[RXRPC_EXTENDED_SACK_SIZE]; } buf; rxrpc_serial_t ack_serial, acked_serial; rxrpc_seq_t first_soft_ack, hard_ack, prev_pkt; @@ -874,6 +876,10 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb) first_soft_ack, prev_pkt, summary.ack_reason, nr_acks); + if ((nr_acks > RXRPC_MAXACKS && !(sp->hdr.flags & RXRPC_EXTENDED_SACK)) || + (nr_acks > RXRPC_MAXACKS_EXTENDED)) + return rxrpc_proto_abort("AKC", call, 0); + switch (buf.ack.reason) { case RXRPC_ACK_PING_RESPONSE: rxrpc_input_ping_response(call, skb->tstamp, acked_serial, @@ -912,7 +918,7 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb) } buf.info.rxMTU = 0; - ioffset = offset + nr_acks + 3; + ioffset = offset + min(nr_acks, RXRPC_MAXACKS) + 3; if (skb->len >= ioffset + sizeof(buf.info) && skb_copy_bits(skb, ioffset, &buf.info, sizeof(buf.info)) < 0) return rxrpc_proto_abort("XAI", call, 0); @@ -969,7 +975,8 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb) } if (nr_acks > 0) { - if (skb_copy_bits(skb, offset, buf.acks, nr_acks) < 0) { + if (skb_copy_bits(skb, offset, buf.acks, + min_t(unsigned int, nr_acks, sizeof(buf.acks))) < 0) { rxrpc_proto_abort("XSA", call, 0); goto out; } diff --git a/net/rxrpc/protocol.h b/net/rxrpc/protocol.h index 49bb972539aa..287986012cd9 100644 --- a/net/rxrpc/protocol.h +++ b/net/rxrpc/protocol.h @@ -51,7 +51,8 @@ struct rxrpc_wire_header { #define RXRPC_CLIENT_INITIATED 0x01 /* signifies a packet generated by a client */ #define RXRPC_REQUEST_ACK 0x02 /* request an unconditional ACK of this packet */ #define RXRPC_LAST_PACKET 0x04 /* the last packet from this side for this call */ -#define RXRPC_MORE_PACKETS 0x08 /* more packets to come */ +#define RXRPC_MORE_PACKETS 0x08 /* [DATA] More packets to come */ +#define RXRPC_EXTENDED_SACK 0x08 /* [ACK] Extended SACK table */ #define RXRPC_JUMBO_PACKET 0x20 /* [DATA] this is a jumbo packet */ #define RXRPC_SLOW_START_OK 0x20 /* [ACK] slow start supported */ @@ -124,7 +125,9 @@ struct rxrpc_ackpacket { #define RXRPC_ACK__INVALID 10 /* Representation of invalid ACK reason */ uint8_t nAcks; /* number of ACKs */ -#define RXRPC_MAXACKS 255 +#define RXRPC_MAXACKS 255 /* Normal maximum number of ACKs */ +#define RXRPC_EXTENDED_SACK_SIZE 256 /* Size of the extended SACK table */ +#define RXRPC_MAXACKS_EXTENDED 2048 /* Maximum number of ACKs in extended SACK table */ uint8_t acks[0]; /* list of ACK/NAKs */ #define RXRPC_ACK_TYPE_NACK 0