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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>
338 lines
8.9 KiB
C
338 lines
8.9 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Broadcom tag support
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*
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* Copyright (C) 2014 Broadcom Corporation
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*/
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#include <linux/dsa/brcm.h>
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#include <linux/etherdevice.h>
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#include <linux/list.h>
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#include <linux/slab.h>
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#include "dsa_priv.h"
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/* Legacy Broadcom tag (6 bytes) */
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#define BRCM_LEG_TAG_LEN 6
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/* Type fields */
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/* 1st byte in the tag */
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#define BRCM_LEG_TYPE_HI 0x88
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/* 2nd byte in the tag */
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#define BRCM_LEG_TYPE_LO 0x74
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/* Tag fields */
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/* 3rd byte in the tag */
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#define BRCM_LEG_UNICAST (0 << 5)
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#define BRCM_LEG_MULTICAST (1 << 5)
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#define BRCM_LEG_EGRESS (2 << 5)
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#define BRCM_LEG_INGRESS (3 << 5)
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/* 6th byte in the tag */
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#define BRCM_LEG_PORT_ID (0xf)
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/* Newer Broadcom tag (4 bytes) */
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#define BRCM_TAG_LEN 4
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/* Tag is constructed and desconstructed using byte by byte access
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* because the tag is placed after the MAC Source Address, which does
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* not make it 4-bytes aligned, so this might cause unaligned accesses
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* on most systems where this is used.
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*/
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/* Ingress and egress opcodes */
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#define BRCM_OPCODE_SHIFT 5
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#define BRCM_OPCODE_MASK 0x7
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/* Ingress fields */
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/* 1st byte in the tag */
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#define BRCM_IG_TC_SHIFT 2
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#define BRCM_IG_TC_MASK 0x7
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/* 2nd byte in the tag */
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#define BRCM_IG_TE_MASK 0x3
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#define BRCM_IG_TS_SHIFT 7
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/* 3rd byte in the tag */
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#define BRCM_IG_DSTMAP2_MASK 1
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#define BRCM_IG_DSTMAP1_MASK 0xff
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/* Egress fields */
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/* 2nd byte in the tag */
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#define BRCM_EG_CID_MASK 0xff
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/* 3rd byte in the tag */
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#define BRCM_EG_RC_MASK 0xff
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#define BRCM_EG_RC_RSVD (3 << 6)
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#define BRCM_EG_RC_EXCEPTION (1 << 5)
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#define BRCM_EG_RC_PROT_SNOOP (1 << 4)
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#define BRCM_EG_RC_PROT_TERM (1 << 3)
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#define BRCM_EG_RC_SWITCH (1 << 2)
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#define BRCM_EG_RC_MAC_LEARN (1 << 1)
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#define BRCM_EG_RC_MIRROR (1 << 0)
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#define BRCM_EG_TC_SHIFT 5
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#define BRCM_EG_TC_MASK 0x7
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#define BRCM_EG_PID_MASK 0x1f
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#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM) || \
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IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND)
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static struct sk_buff *brcm_tag_xmit_ll(struct sk_buff *skb,
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struct net_device *dev,
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unsigned int offset)
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{
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struct dsa_port *dp = dsa_slave_to_port(dev);
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u16 queue = skb_get_queue_mapping(skb);
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u8 *brcm_tag;
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/* The Ethernet switch we are interfaced with needs packets to be at
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* least 64 bytes (including FCS) otherwise they will be discarded when
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* they enter the switch port logic. When Broadcom tags are enabled, we
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* need to make sure that packets are at least 68 bytes
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* (including FCS and tag) because the length verification is done after
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* the Broadcom tag is stripped off the ingress packet.
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*
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* Let dsa_slave_xmit() free the SKB
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*/
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if (__skb_put_padto(skb, ETH_ZLEN + BRCM_TAG_LEN, false))
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return NULL;
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skb_push(skb, BRCM_TAG_LEN);
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if (offset)
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memmove(skb->data, skb->data + BRCM_TAG_LEN, offset);
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brcm_tag = skb->data + offset;
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/* Set the ingress opcode, traffic class, tag enforcment is
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* deprecated
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*/
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brcm_tag[0] = (1 << BRCM_OPCODE_SHIFT) |
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((queue & BRCM_IG_TC_MASK) << BRCM_IG_TC_SHIFT);
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brcm_tag[1] = 0;
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brcm_tag[2] = 0;
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if (dp->index == 8)
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brcm_tag[2] = BRCM_IG_DSTMAP2_MASK;
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brcm_tag[3] = (1 << dp->index) & BRCM_IG_DSTMAP1_MASK;
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/* Now tell the master network device about the desired output queue
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* as well
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*/
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skb_set_queue_mapping(skb, BRCM_TAG_SET_PORT_QUEUE(dp->index, queue));
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return skb;
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}
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/* Frames with this tag have one of these two layouts:
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* -----------------------------------
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* | MAC DA | MAC SA | 4b tag | Type | DSA_TAG_PROTO_BRCM
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* -----------------------------------
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* -----------------------------------
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* | 4b tag | MAC DA | MAC SA | Type | DSA_TAG_PROTO_BRCM_PREPEND
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* -----------------------------------
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* In both cases, at receive time, skb->data points 2 bytes before the actual
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* Ethernet type field and we have an offset of 4bytes between where skb->data
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* and where the payload starts. So the same low-level receive function can be
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* used.
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*/
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static struct sk_buff *brcm_tag_rcv_ll(struct sk_buff *skb,
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struct net_device *dev,
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struct packet_type *pt,
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unsigned int offset)
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{
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int source_port;
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u8 *brcm_tag;
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if (unlikely(!pskb_may_pull(skb, BRCM_TAG_LEN)))
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return NULL;
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brcm_tag = skb->data - offset;
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/* The opcode should never be different than 0b000 */
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if (unlikely((brcm_tag[0] >> BRCM_OPCODE_SHIFT) & BRCM_OPCODE_MASK))
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return NULL;
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/* We should never see a reserved reason code without knowing how to
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* handle it
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*/
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if (unlikely(brcm_tag[2] & BRCM_EG_RC_RSVD))
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return NULL;
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/* Locate which port this is coming from */
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source_port = brcm_tag[3] & BRCM_EG_PID_MASK;
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skb->dev = dsa_master_find_slave(dev, 0, source_port);
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if (!skb->dev)
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return NULL;
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/* Remove Broadcom tag and update checksum */
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skb_pull_rcsum(skb, BRCM_TAG_LEN);
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skb->offload_fwd_mark = 1;
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return skb;
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}
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#endif
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#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM)
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static struct sk_buff *brcm_tag_xmit(struct sk_buff *skb,
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struct net_device *dev)
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{
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/* Build the tag after the MAC Source Address */
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return brcm_tag_xmit_ll(skb, dev, 2 * ETH_ALEN);
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}
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static struct sk_buff *brcm_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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struct sk_buff *nskb;
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/* skb->data points to the EtherType, the tag is right before it */
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nskb = brcm_tag_rcv_ll(skb, dev, pt, 2);
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if (!nskb)
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return nskb;
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/* Move the Ethernet DA and SA */
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memmove(nskb->data - ETH_HLEN,
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nskb->data - ETH_HLEN - BRCM_TAG_LEN,
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2 * ETH_ALEN);
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return nskb;
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}
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static const struct dsa_device_ops brcm_netdev_ops = {
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.name = "brcm",
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.proto = DSA_TAG_PROTO_BRCM,
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.xmit = brcm_tag_xmit,
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.rcv = brcm_tag_rcv,
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.needed_headroom = BRCM_TAG_LEN,
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};
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DSA_TAG_DRIVER(brcm_netdev_ops);
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MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM);
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#endif
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#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY)
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static struct sk_buff *brcm_leg_tag_xmit(struct sk_buff *skb,
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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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u8 *brcm_tag;
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/* The Ethernet switch we are interfaced with needs packets to be at
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* least 64 bytes (including FCS) otherwise they will be discarded when
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* they enter the switch port logic. When Broadcom tags are enabled, we
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* need to make sure that packets are at least 70 bytes
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* (including FCS and tag) because the length verification is done after
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* the Broadcom tag is stripped off the ingress packet.
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*
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* Let dsa_slave_xmit() free the SKB
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*/
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if (__skb_put_padto(skb, ETH_ZLEN + BRCM_LEG_TAG_LEN, false))
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return NULL;
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skb_push(skb, BRCM_LEG_TAG_LEN);
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memmove(skb->data, skb->data + BRCM_LEG_TAG_LEN, 2 * ETH_ALEN);
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brcm_tag = skb->data + 2 * ETH_ALEN;
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/* Broadcom tag type */
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brcm_tag[0] = BRCM_LEG_TYPE_HI;
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brcm_tag[1] = BRCM_LEG_TYPE_LO;
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/* Broadcom tag value */
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brcm_tag[2] = BRCM_LEG_EGRESS;
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brcm_tag[3] = 0;
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brcm_tag[4] = 0;
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brcm_tag[5] = dp->index & BRCM_LEG_PORT_ID;
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return skb;
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}
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static struct sk_buff *brcm_leg_tag_rcv(struct sk_buff *skb,
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struct net_device *dev,
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struct packet_type *pt)
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{
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int source_port;
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u8 *brcm_tag;
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if (unlikely(!pskb_may_pull(skb, BRCM_LEG_PORT_ID)))
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return NULL;
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brcm_tag = skb->data - 2;
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source_port = brcm_tag[5] & BRCM_LEG_PORT_ID;
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skb->dev = dsa_master_find_slave(dev, 0, source_port);
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if (!skb->dev)
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return NULL;
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/* Remove Broadcom tag and update checksum */
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skb_pull_rcsum(skb, BRCM_LEG_TAG_LEN);
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skb->offload_fwd_mark = 1;
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/* Move the Ethernet DA and SA */
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memmove(skb->data - ETH_HLEN,
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skb->data - ETH_HLEN - BRCM_LEG_TAG_LEN,
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2 * ETH_ALEN);
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return skb;
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}
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static const struct dsa_device_ops brcm_legacy_netdev_ops = {
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.name = "brcm-legacy",
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.proto = DSA_TAG_PROTO_BRCM_LEGACY,
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.xmit = brcm_leg_tag_xmit,
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.rcv = brcm_leg_tag_rcv,
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.needed_headroom = BRCM_LEG_TAG_LEN,
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};
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DSA_TAG_DRIVER(brcm_legacy_netdev_ops);
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MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM_LEGACY);
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#endif /* CONFIG_NET_DSA_TAG_BRCM_LEGACY */
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#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND)
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static struct sk_buff *brcm_tag_xmit_prepend(struct sk_buff *skb,
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struct net_device *dev)
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{
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/* tag is prepended to the packet */
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return brcm_tag_xmit_ll(skb, dev, 0);
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}
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static struct sk_buff *brcm_tag_rcv_prepend(struct sk_buff *skb,
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struct net_device *dev,
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struct packet_type *pt)
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{
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/* tag is prepended to the packet */
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return brcm_tag_rcv_ll(skb, dev, pt, ETH_HLEN);
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}
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static const struct dsa_device_ops brcm_prepend_netdev_ops = {
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.name = "brcm-prepend",
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.proto = DSA_TAG_PROTO_BRCM_PREPEND,
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.xmit = brcm_tag_xmit_prepend,
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.rcv = brcm_tag_rcv_prepend,
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.needed_headroom = BRCM_TAG_LEN,
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};
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DSA_TAG_DRIVER(brcm_prepend_netdev_ops);
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MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM_PREPEND);
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#endif
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static struct dsa_tag_driver *dsa_tag_driver_array[] = {
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#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM)
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&DSA_TAG_DRIVER_NAME(brcm_netdev_ops),
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#endif
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#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY)
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&DSA_TAG_DRIVER_NAME(brcm_legacy_netdev_ops),
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#endif
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#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND)
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&DSA_TAG_DRIVER_NAME(brcm_prepend_netdev_ops),
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#endif
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};
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module_dsa_tag_drivers(dsa_tag_driver_array);
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MODULE_LICENSE("GPL");
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