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4e50025129
Some really really weird switches just couldn't decide whether to use a normal or a tail tagger, so they just did both. This creates problems for DSA, because we only have the concept of an 'overhead' which can be applied to the headroom or to the tailroom of the skb (like for example during the central TX reallocation procedure), depending on the value of bool tail_tag, but not to both. We need to generalize DSA to cater for these odd switches by transforming the 'overhead / tail_tag' pair into 'needed_headroom / needed_tailroom'. The DSA master's MTU is increased to account for both. The flow dissector code is modified such that it only calls the DSA adjustment callback if the tagger has a non-zero header length. Taggers are trivially modified to declare either needed_headroom or needed_tailroom, based on the tail_tag value that they currently declare. Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
100 lines
2.6 KiB
C
100 lines
2.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (c) 2015, The Linux Foundation. All rights reserved.
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*/
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#include <linux/etherdevice.h>
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#include "dsa_priv.h"
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#define QCA_HDR_LEN 2
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#define QCA_HDR_VERSION 0x2
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#define QCA_HDR_RECV_VERSION_MASK GENMASK(15, 14)
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#define QCA_HDR_RECV_VERSION_S 14
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#define QCA_HDR_RECV_PRIORITY_MASK GENMASK(13, 11)
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#define QCA_HDR_RECV_PRIORITY_S 11
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#define QCA_HDR_RECV_TYPE_MASK GENMASK(10, 6)
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#define QCA_HDR_RECV_TYPE_S 6
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#define QCA_HDR_RECV_FRAME_IS_TAGGED BIT(3)
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#define QCA_HDR_RECV_SOURCE_PORT_MASK GENMASK(2, 0)
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#define QCA_HDR_XMIT_VERSION_MASK GENMASK(15, 14)
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#define QCA_HDR_XMIT_VERSION_S 14
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#define QCA_HDR_XMIT_PRIORITY_MASK GENMASK(13, 11)
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#define QCA_HDR_XMIT_PRIORITY_S 11
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#define QCA_HDR_XMIT_CONTROL_MASK GENMASK(10, 8)
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#define QCA_HDR_XMIT_CONTROL_S 8
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#define QCA_HDR_XMIT_FROM_CPU BIT(7)
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#define QCA_HDR_XMIT_DP_BIT_MASK GENMASK(6, 0)
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static struct sk_buff *qca_tag_xmit(struct sk_buff *skb, struct net_device *dev)
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{
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struct dsa_port *dp = dsa_slave_to_port(dev);
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__be16 *phdr;
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u16 hdr;
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skb_push(skb, QCA_HDR_LEN);
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memmove(skb->data, skb->data + QCA_HDR_LEN, 2 * ETH_ALEN);
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phdr = (__be16 *)(skb->data + 2 * ETH_ALEN);
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/* Set the version field, and set destination port information */
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hdr = QCA_HDR_VERSION << QCA_HDR_XMIT_VERSION_S |
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QCA_HDR_XMIT_FROM_CPU | BIT(dp->index);
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*phdr = htons(hdr);
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return skb;
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}
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static struct sk_buff *qca_tag_rcv(struct sk_buff *skb, struct net_device *dev,
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struct packet_type *pt)
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{
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u8 ver;
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u16 hdr;
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int port;
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__be16 *phdr;
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if (unlikely(!pskb_may_pull(skb, QCA_HDR_LEN)))
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return NULL;
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/* The QCA header is added by the switch between src addr and Ethertype
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* At this point, skb->data points to ethertype so header should be
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* right before
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*/
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phdr = (__be16 *)(skb->data - 2);
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hdr = ntohs(*phdr);
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/* Make sure the version is correct */
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ver = (hdr & QCA_HDR_RECV_VERSION_MASK) >> QCA_HDR_RECV_VERSION_S;
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if (unlikely(ver != QCA_HDR_VERSION))
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return NULL;
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/* Remove QCA tag and recalculate checksum */
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skb_pull_rcsum(skb, QCA_HDR_LEN);
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memmove(skb->data - ETH_HLEN, skb->data - ETH_HLEN - QCA_HDR_LEN,
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ETH_HLEN - QCA_HDR_LEN);
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/* Get source port information */
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port = (hdr & QCA_HDR_RECV_SOURCE_PORT_MASK);
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skb->dev = dsa_master_find_slave(dev, 0, port);
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if (!skb->dev)
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return NULL;
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return skb;
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}
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static const struct dsa_device_ops qca_netdev_ops = {
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.name = "qca",
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.proto = DSA_TAG_PROTO_QCA,
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.xmit = qca_tag_xmit,
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.rcv = qca_tag_rcv,
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.needed_headroom = QCA_HDR_LEN,
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};
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_QCA);
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module_dsa_tag_driver(qca_netdev_ops);
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