[linux-2.6-block.git] / net / dsa / tag_hellcreek.c

// SPDX-License-Identifier: (GPL-2.0 OR MIT)
/*
 * net/dsa/tag_hellcreek.c - Hirschmann Hellcreek switch tag format handling
 *
 * Copyright (C) 2019,2020 Linutronix GmbH
 * Author Kurt Kanzenbach <kurt@linutronix.de>
 *
 * Based on tag_ksz.c.
 */

#include <linux/skbuff.h>
#include <net/dsa.h>

#include "tag.h"

#define HELLCREEK_NAME		"hellcreek"

#define HELLCREEK_TAG_LEN	1

static struct sk_buff *hellcreek_xmit(struct sk_buff *skb,
				      struct net_device *dev)
{
	struct dsa_port *dp = dsa_slave_to_port(dev);
	u8 *tag;

	/* Calculate checksums (if required) before adding the trailer tag to
	 * avoid including it in calculations. That would lead to wrong
	 * checksums after the switch strips the tag.
	 */
	if (skb->ip_summed == CHECKSUM_PARTIAL &&
	    skb_checksum_help(skb))
		return NULL;

	/* Tag encoding */
	tag  = skb_put(skb, HELLCREEK_TAG_LEN);
	*tag = BIT(dp->index);

	return skb;
}

static struct sk_buff *hellcreek_rcv(struct sk_buff *skb,
				     struct net_device *dev)
{
	/* Tag decoding */
	u8 *tag = skb_tail_pointer(skb) - HELLCREEK_TAG_LEN;
	unsigned int port = tag[0] & 0x03;

	skb->dev = dsa_master_find_slave(dev, 0, port);
	if (!skb->dev) {
		netdev_warn_once(dev, "Failed to get source port: %d\n", port);
		return NULL;
	}

	if (pskb_trim_rcsum(skb, skb->len - HELLCREEK_TAG_LEN))
		return NULL;

	dsa_default_offload_fwd_mark(skb);

	return skb;
}

static const struct dsa_device_ops hellcreek_netdev_ops = {
	.name	  = HELLCREEK_NAME,
	.proto	  = DSA_TAG_PROTO_HELLCREEK,
	.xmit	  = hellcreek_xmit,
	.rcv	  = hellcreek_rcv,
	.needed_tailroom = HELLCREEK_TAG_LEN,
};

MODULE_LICENSE("Dual MIT/GPL");
MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_HELLCREEK, HELLCREEK_NAME);

module_dsa_tag_driver(hellcreek_netdev_ops);
Commit	Line	Data
01ef09ca KK	1	// SPDX-License-Identifier: (GPL-2.0 OR MIT)
	2	/*
	3	* net/dsa/tag_hellcreek.c - Hirschmann Hellcreek switch tag format handling
	4	*
	5	* Copyright (C) 2019,2020 Linutronix GmbH
	6	* Author Kurt Kanzenbach <kurt@linutronix.de>
	7	*
	8	* Based on tag_ksz.c.
	9	*/
	10
8551fad6	11	#include <linux/skbuff.h>
01ef09ca KK	12	#include <net/dsa.h>
01ef09ca KK	13
bd954b82	14	#include "tag.h"
01ef09ca	15
94793a56 VO	16	#define HELLCREEK_NAME "hellcreek"
94793a56 VO	17
01ef09ca KK	18	#define HELLCREEK_TAG_LEN 1
	19
	20	static struct sk_buff hellcreek_xmit(struct sk_buff skb,
	21	struct net_device *dev)
	22	{
	23	struct dsa_port *dp = dsa_slave_to_port(dev);
	24	u8 *tag;
	25
0763120b KK	26	/* Calculate checksums (if required) before adding the trailer tag to
	27	* avoid including it in calculations. That would lead to wrong
	28	* checksums after the switch strips the tag.
	29	*/
	30	if (skb->ip_summed == CHECKSUM_PARTIAL &&
	31	skb_checksum_help(skb))
	32	return NULL;
	33
01ef09ca KK	34	/* Tag encoding */
	35	tag = skb_put(skb, HELLCREEK_TAG_LEN);
	36	*tag = BIT(dp->index);
	37
	38	return skb;
	39	}
	40
	41	static struct sk_buff hellcreek_rcv(struct sk_buff skb,
29a097b7	42	struct net_device *dev)
01ef09ca KK	43	{
	44	/* Tag decoding */
	45	u8 *tag = skb_tail_pointer(skb) - HELLCREEK_TAG_LEN;
	46	unsigned int port = tag[0] & 0x03;
	47
	48	skb->dev = dsa_master_find_slave(dev, 0, port);
	49	if (!skb->dev) {
52267ce2	50	netdev_warn_once(dev, "Failed to get source port: %d\n", port);
01ef09ca KK	51	return NULL;
	52	}
	53
d4edb506 AC	54	if (pskb_trim_rcsum(skb, skb->len - HELLCREEK_TAG_LEN))
d4edb506 AC	55	return NULL;
01ef09ca	56
bea79078	57	dsa_default_offload_fwd_mark(skb);
01ef09ca KK	58
	59	return skb;
	60	}
	61
	62	static const struct dsa_device_ops hellcreek_netdev_ops = {
94793a56	63	.name = HELLCREEK_NAME,
01ef09ca KK	64	.proto = DSA_TAG_PROTO_HELLCREEK,
	65	.xmit = hellcreek_xmit,
	66	.rcv = hellcreek_rcv,
4e500251	67	.needed_tailroom = HELLCREEK_TAG_LEN,
01ef09ca KK	68	};
	69
	70	MODULE_LICENSE("Dual MIT/GPL");
94793a56	71	MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_HELLCREEK, HELLCREEK_NAME);
01ef09ca KK	72
01ef09ca KK	73	module_dsa_tag_driver(hellcreek_netdev_ops);