[mirror_ubuntu-jammy-kernel.git] / include / net / mctp.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Management Component Transport Protocol (MCTP)
 *
 * Copyright (c) 2021 Code Construct
 * Copyright (c) 2021 Google
 */

#ifndef __NET_MCTP_H
#define __NET_MCTP_H

#include <linux/bits.h>
#include <linux/mctp.h>
#include <net/net_namespace.h>

/* MCTP packet definitions */
struct mctp_hdr {
	u8	ver;
	u8	dest;
	u8	src;
	u8	flags_seq_tag;
};

#define MCTP_VER_MIN	1
#define MCTP_VER_MAX	1

/* Definitions for flags_seq_tag field */
#define MCTP_HDR_FLAG_SOM	BIT(7)
#define MCTP_HDR_FLAG_EOM	BIT(6)
#define MCTP_HDR_FLAG_TO	BIT(3)
#define MCTP_HDR_FLAGS		GENMASK(5, 3)
#define MCTP_HDR_SEQ_SHIFT	4
#define MCTP_HDR_SEQ_MASK	GENMASK(1, 0)
#define MCTP_HDR_TAG_SHIFT	0
#define MCTP_HDR_TAG_MASK	GENMASK(2, 0)

#define MCTP_HEADER_MAXLEN	4

static inline bool mctp_address_ok(mctp_eid_t eid)
{
	return eid >= 8 && eid < 255;
}

static inline struct mctp_hdr *mctp_hdr(struct sk_buff *skb)
{
	return (struct mctp_hdr *)skb_network_header(skb);
}

struct mctp_skb_cb {
	unsigned int	magic;
	unsigned int	net;
	mctp_eid_t	src;
};

/* skb control-block accessors with a little extra debugging for initial
 * development.
 *
 * TODO: remove checks & mctp_skb_cb->magic; replace callers of __mctp_cb
 * with mctp_cb().
 *
 * __mctp_cb() is only for the initial ingress code; we should see ->magic set
 * at all times after this.
 */
static inline struct mctp_skb_cb *__mctp_cb(struct sk_buff *skb)
{
	struct mctp_skb_cb *cb = (void *)skb->cb;

	cb->magic = 0x4d435450;
	return cb;
}

static inline struct mctp_skb_cb *mctp_cb(struct sk_buff *skb)
{
	struct mctp_skb_cb *cb = (void *)skb->cb;

	WARN_ON(cb->magic != 0x4d435450);
	return (void *)(skb->cb);
}

/* Route definition.
 *
 * These are held in the pernet->mctp.routes list, with RCU protection for
 * removed routes. We hold a reference to the netdev; routes need to be
 * dropped on NETDEV_UNREGISTER events.
 *
 * Updates to the route table are performed under rtnl; all reads under RCU,
 * so routes cannot be referenced over a RCU grace period. Specifically: A
 * caller cannot block between mctp_route_lookup and passing the route to
 * mctp_do_route.
 */
struct mctp_route {
	mctp_eid_t		min, max;

	struct mctp_dev		*dev;
	unsigned int		mtu;
	int			(*output)(struct mctp_route *route,
					  struct sk_buff *skb);

	struct list_head	list;
	refcount_t		refs;
	struct rcu_head		rcu;
};

/* route interfaces */
struct mctp_route *mctp_route_lookup(struct net *net, unsigned int dnet,
				     mctp_eid_t daddr);

int mctp_do_route(struct mctp_route *rt, struct sk_buff *skb);

int mctp_local_output(struct sock *sk, struct mctp_route *rt,
		      struct sk_buff *skb, mctp_eid_t daddr, u8 req_tag);

/* routing <--> device interface */
unsigned int mctp_default_net(struct net *net);
int mctp_default_net_set(struct net *net, unsigned int index);
int mctp_route_add_local(struct mctp_dev *mdev, mctp_eid_t addr);
int mctp_route_remove_local(struct mctp_dev *mdev, mctp_eid_t addr);
void mctp_route_remove_dev(struct mctp_dev *mdev);

/* neighbour definitions */
enum mctp_neigh_source {
	MCTP_NEIGH_STATIC,
	MCTP_NEIGH_DISCOVER,
};

struct mctp_neigh {
	struct mctp_dev		*dev;
	mctp_eid_t		eid;
	enum mctp_neigh_source	source;

	unsigned char		ha[MAX_ADDR_LEN];

	struct list_head	list;
	struct rcu_head		rcu;
};

int mctp_neigh_init(void);
void mctp_neigh_exit(void);

// ret_hwaddr may be NULL, otherwise must have space for MAX_ADDR_LEN
int mctp_neigh_lookup(struct mctp_dev *dev, mctp_eid_t eid,
		      void *ret_hwaddr);
void mctp_neigh_remove_dev(struct mctp_dev *mdev);

int mctp_routes_init(void);
void mctp_routes_exit(void);

void mctp_device_init(void);
void mctp_device_exit(void);

#endif /* __NET_MCTP_H */
Commit	Line	Data
2c8e2e9a JK	1	/* SPDX-License-Identifier: GPL-2.0 */
	2	/*
	3	* Management Component Transport Protocol (MCTP)
	4	*
	5	* Copyright (c) 2021 Code Construct
	6	* Copyright (c) 2021 Google
	7	*/
	8
	9	#ifndef __NET_MCTP_H
	10	#define __NET_MCTP_H
	11
	12	#include <linux/bits.h>
583be982	13	#include <linux/mctp.h>
889b7da2	14	#include <net/net_namespace.h>
2c8e2e9a JK	15
	16	/* MCTP packet definitions */
	17	struct mctp_hdr {
	18	u8 ver;
	19	u8 dest;
	20	u8 src;
	21	u8 flags_seq_tag;
	22	};
	23
	24	#define MCTP_VER_MIN 1
	25	#define MCTP_VER_MAX 1
	26
	27	/* Definitions for flags_seq_tag field */
	28	#define MCTP_HDR_FLAG_SOM BIT(7)
	29	#define MCTP_HDR_FLAG_EOM BIT(6)
	30	#define MCTP_HDR_FLAG_TO BIT(3)
	31	#define MCTP_HDR_FLAGS GENMASK(5, 3)
	32	#define MCTP_HDR_SEQ_SHIFT 4
	33	#define MCTP_HDR_SEQ_MASK GENMASK(1, 0)
	34	#define MCTP_HDR_TAG_SHIFT 0
	35	#define MCTP_HDR_TAG_MASK GENMASK(2, 0)
	36
889b7da2 JK	37	#define MCTP_HEADER_MAXLEN 4
889b7da2 JK	38
583be982 JK	39	static inline bool mctp_address_ok(mctp_eid_t eid)
	40	{
	41	return eid >= 8 && eid < 255;
	42	}
	43
	44	static inline struct mctp_hdr mctp_hdr(struct sk_buff skb)
	45	{
	46	return (struct mctp_hdr *)skb_network_header(skb);
	47	}
	48
889b7da2 JK	49	struct mctp_skb_cb {
	50	unsigned int magic;
	51	unsigned int net;
	52	mctp_eid_t src;
	53	};
	54
	55	/* skb control-block accessors with a little extra debugging for initial
	56	* development.
	57	*
	58	* TODO: remove checks & mctp_skb_cb->magic; replace callers of __mctp_cb
	59	* with mctp_cb().
	60	*
	61	* __mctp_cb() is only for the initial ingress code; we should see ->magic set
	62	* at all times after this.
	63	*/
	64	static inline struct mctp_skb_cb __mctp_cb(struct sk_buff skb)
	65	{
	66	struct mctp_skb_cb cb = (void )skb->cb;
	67
	68	cb->magic = 0x4d435450;
	69	return cb;
	70	}
	71
	72	static inline struct mctp_skb_cb mctp_cb(struct sk_buff skb)
	73	{
	74	struct mctp_skb_cb cb = (void )skb->cb;
	75
	76	WARN_ON(cb->magic != 0x4d435450);
	77	return (void *)(skb->cb);
	78	}
	79
	80	/* Route definition.
	81	*
	82	* These are held in the pernet->mctp.routes list, with RCU protection for
	83	* removed routes. We hold a reference to the netdev; routes need to be
	84	* dropped on NETDEV_UNREGISTER events.
	85	*
	86	* Updates to the route table are performed under rtnl; all reads under RCU,
	87	* so routes cannot be referenced over a RCU grace period. Specifically: A
	88	* caller cannot block between mctp_route_lookup and passing the route to
	89	* mctp_do_route.
	90	*/
	91	struct mctp_route {
	92	mctp_eid_t min, max;
	93
	94	struct mctp_dev *dev;
	95	unsigned int mtu;
	96	int (output)(struct mctp_route route,
	97	struct sk_buff *skb);
	98
	99	struct list_head list;
	100	refcount_t refs;
	101	struct rcu_head rcu;
	102	};
	103
	104	/* route interfaces */
	105	struct mctp_route mctp_route_lookup(struct net net, unsigned int dnet,
	106	mctp_eid_t daddr);
	107
	108	int mctp_do_route(struct mctp_route rt, struct sk_buff skb);
	109
	110	int mctp_local_output(struct sock sk, struct mctp_route rt,
	111	struct sk_buff *skb, mctp_eid_t daddr, u8 req_tag);
	112
113	/* routing <--> device interface */
06d2f4c5 MJ	114	unsigned int mctp_default_net(struct net *net);
06d2f4c5 MJ	115	int mctp_default_net_set(struct net *net, unsigned int index);
889b7da2 JK	116	int mctp_route_add_local(struct mctp_dev *mdev, mctp_eid_t addr);
	117	int mctp_route_remove_local(struct mctp_dev *mdev, mctp_eid_t addr);
	118	void mctp_route_remove_dev(struct mctp_dev *mdev);
	119
4d8b9319 MJ	120	/* neighbour definitions */
	121	enum mctp_neigh_source {
	122	MCTP_NEIGH_STATIC,
	123	MCTP_NEIGH_DISCOVER,
	124	};
	125
	126	struct mctp_neigh {
	127	struct mctp_dev *dev;
	128	mctp_eid_t eid;
	129	enum mctp_neigh_source source;
	130
	131	unsigned char ha[MAX_ADDR_LEN];
	132
	133	struct list_head list;
	134	struct rcu_head rcu;
	135	};
	136
	137	int mctp_neigh_init(void);
	138	void mctp_neigh_exit(void);
	139
	140	// ret_hwaddr may be NULL, otherwise must have space for MAX_ADDR_LEN
	141	int mctp_neigh_lookup(struct mctp_dev *dev, mctp_eid_t eid,
	142	void *ret_hwaddr);
	143	void mctp_neigh_remove_dev(struct mctp_dev *mdev);
	144
889b7da2 JK	145	int mctp_routes_init(void);
	146	void mctp_routes_exit(void);
	147
583be982 JK	148	void mctp_device_init(void);
	149	void mctp_device_exit(void);
	150
2c8e2e9a	151	#endif /* __NET_MCTP_H */