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bd954b8260
It would be nice if tagging protocol drivers could include just the header they need, since they are (mostly) data path and isolated from most of the other DSA core code does. Create a tag.c and a tag.h file which are meant to support tagging protocol drivers. Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
116 lines
2.9 KiB
C
116 lines
2.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2022 Schneider Electric
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*
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* Clément Léger <clement.leger@bootlin.com>
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*/
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#include <linux/bitfield.h>
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#include <linux/etherdevice.h>
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#include <linux/if_ether.h>
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#include <net/dsa.h>
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#include "tag.h"
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/* To define the outgoing port and to discover the incoming port a TAG is
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* inserted after Src MAC :
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*
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* Dest MAC Src MAC TAG Type
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* ...| 1 2 3 4 5 6 | 1 2 3 4 5 6 | 1 2 3 4 5 6 7 8 | 1 2 |...
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* |<--------------->|
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*
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* See struct a5psw_tag for layout
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*/
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#define A5PSW_NAME "a5psw"
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#define ETH_P_DSA_A5PSW 0xE001
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#define A5PSW_TAG_LEN 8
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#define A5PSW_CTRL_DATA_FORCE_FORWARD BIT(0)
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/* This is both used for xmit tag and rcv tagging */
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#define A5PSW_CTRL_DATA_PORT GENMASK(3, 0)
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struct a5psw_tag {
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__be16 ctrl_tag;
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__be16 ctrl_data;
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__be16 ctrl_data2_hi;
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__be16 ctrl_data2_lo;
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};
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static struct sk_buff *a5psw_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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struct a5psw_tag *ptag;
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u32 data2_val;
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BUILD_BUG_ON(sizeof(*ptag) != A5PSW_TAG_LEN);
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/* The Ethernet switch we are interfaced with needs packets to be at
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* least 60 bytes otherwise they will be discarded when they enter the
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* switch port logic.
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*/
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if (__skb_put_padto(skb, ETH_ZLEN, false))
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return NULL;
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/* provide 'A5PSW_TAG_LEN' bytes additional space */
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skb_push(skb, A5PSW_TAG_LEN);
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/* make room between MACs and Ether-Type to insert tag */
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dsa_alloc_etype_header(skb, A5PSW_TAG_LEN);
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ptag = dsa_etype_header_pos_tx(skb);
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data2_val = FIELD_PREP(A5PSW_CTRL_DATA_PORT, BIT(dp->index));
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ptag->ctrl_tag = htons(ETH_P_DSA_A5PSW);
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ptag->ctrl_data = htons(A5PSW_CTRL_DATA_FORCE_FORWARD);
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ptag->ctrl_data2_lo = htons(data2_val);
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ptag->ctrl_data2_hi = 0;
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return skb;
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}
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static struct sk_buff *a5psw_tag_rcv(struct sk_buff *skb,
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struct net_device *dev)
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{
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struct a5psw_tag *tag;
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int port;
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if (unlikely(!pskb_may_pull(skb, A5PSW_TAG_LEN))) {
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dev_warn_ratelimited(&dev->dev,
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"Dropping packet, cannot pull\n");
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return NULL;
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}
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tag = dsa_etype_header_pos_rx(skb);
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if (tag->ctrl_tag != htons(ETH_P_DSA_A5PSW)) {
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dev_warn_ratelimited(&dev->dev, "Dropping packet due to invalid TAG marker\n");
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return NULL;
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}
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port = FIELD_GET(A5PSW_CTRL_DATA_PORT, ntohs(tag->ctrl_data));
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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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skb_pull_rcsum(skb, A5PSW_TAG_LEN);
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dsa_strip_etype_header(skb, A5PSW_TAG_LEN);
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dsa_default_offload_fwd_mark(skb);
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return skb;
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}
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static const struct dsa_device_ops a5psw_netdev_ops = {
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.name = A5PSW_NAME,
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.proto = DSA_TAG_PROTO_RZN1_A5PSW,
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.xmit = a5psw_tag_xmit,
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.rcv = a5psw_tag_rcv,
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.needed_headroom = A5PSW_TAG_LEN,
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};
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_A5PSW, A5PSW_NAME);
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module_dsa_tag_driver(a5psw_netdev_ops);
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