/* 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 <linux/netdevice.h>#include <net/net_namespace.h>#include <net/sock.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 ver field */#define MCTP_HDR_VER_MASK	GENMASK(3, 0) /* 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_INITIAL_DEFAULT_NET	1 static inline bool mctp_address_unicast(mctp_eid_t eid){	return eid >= 8 && eid < 255;} static inline bool mctp_address_broadcast(mctp_eid_t eid){	return eid == 255;} static inline bool mctp_address_null(mctp_eid_t eid){	return eid == 0;} static inline bool mctp_address_matches(mctp_eid_t match, mctp_eid_t eid){	return match == eid || match == MCTP_ADDR_ANY;} static inline struct mctp_hdr *mctp_hdr(struct sk_buff *skb){	return (struct mctp_hdr *)skb_network_header(skb);} /* socket implementation */struct mctp_sock {	struct sock	sk; 	/* bind() params */	unsigned int	bind_net;	mctp_eid_t	bind_local_addr;	mctp_eid_t	bind_peer_addr;	unsigned int	bind_peer_net;	bool		bind_peer_set;	__u8		bind_type; 	/* sendmsg()/recvmsg() uses struct sockaddr_mctp_ext */	bool		addr_ext; 	/* list of mctp_sk_key, for incoming tag lookup. updates protected	 * by sk->net->keys_lock	 */	struct hlist_head keys; 	/* mechanism for expiring allocated keys; will release an allocated	 * tag, and any netdev state for a request/response pairing	 */	struct timer_list key_expiry;}; /* Key for matching incoming packets to sockets or reassembly contexts. * Packets are matched on (peer EID, local EID, tag). * * Lifetime / locking requirements: * *  - individual key data (ie, the struct itself) is protected by key->lock; *    changes must be made with that lock held. * *  - the lookup fields: peer_addr, local_addr and tag are set before the *    key is added to lookup lists, and never updated. * *  - A ref to the key must be held (throuh key->refs) if a pointer to the *    key is to be accessed after key->lock is released. * *  - a mctp_sk_key contains a reference to a struct sock; this is valid *    for the life of the key. On sock destruction (through unhash), the key is *    removed from lists (see below), and marked invalid. * * - these mctp_sk_keys appear on two lists: *     1) the struct mctp_sock->keys list *     2) the struct netns_mctp->keys list * *   presences on these lists requires a (single) refcount to be held; both *   lists are updated as a single operation. * *   Updates and lookups in either list are performed under the *   netns_mctp->keys lock. Lookup functions will need to lock the key and *   take a reference before unlocking the keys_lock. Consequently, the list's *   keys_lock *cannot* be acquired with the individual key->lock held. * * - a key may have a sk_buff attached as part of an in-progress message *   reassembly (->reasm_head). The reasm data is protected by the individual *   key->lock. * * - there are two destruction paths for a mctp_sk_key: * *    - through socket unhash (see mctp_sk_unhash). This performs the list *      removal under keys_lock. * *    - where a key is established to receive a reply message: after receiving *      the (complete) reply, or during reassembly errors. Here, we clean up *      the reassembly context (marking reasm_dead, to prevent another from *      starting), and remove the socket from the netns & socket lists. * *    - through an expiry timeout, on a per-socket timer */struct mctp_sk_key {	unsigned int	net;	mctp_eid_t	peer_addr;	mctp_eid_t	local_addr; /* MCTP_ADDR_ANY for local owned tags */	__u8		tag; /* incoming tag match; invert TO for local */ 	/* we hold a ref to sk when set */	struct sock	*sk; 	/* routing lookup list */	struct hlist_node hlist; 	/* per-socket list */	struct hlist_node sklist; 	/* lock protects against concurrent updates to the reassembly and	 * expiry data below.	 */	spinlock_t	lock; 	/* Keys are referenced during the output path, which may sleep */	refcount_t	refs; 	/* incoming fragment reassembly context */	struct sk_buff	*reasm_head;	struct sk_buff	**reasm_tailp;	bool		reasm_dead;	u8		last_seq; 	/* key validity */	bool		valid; 	/* expiry timeout; valid (above) cleared on expiry */	unsigned long	expiry; 	/* free to use for device flow state tracking. Initialised to	 * zero on initial key creation	 */	unsigned long	dev_flow_state;	struct mctp_dev	*dev; 	/* a tag allocated with SIOCMCTPALLOCTAG ioctl will not expire	 * automatically on timeout or response, instead SIOCMCTPDROPTAG	 * is used.	 */	bool		manual_alloc;}; struct mctp_skb_cb {	unsigned int	magic;	unsigned int	net;	/* fields below provide extended addressing for ingress to recvmsg() */	int		ifindex;	unsigned char	halen;	unsigned char	haddr[MAX_ADDR_LEN];}; /* 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; 	BUILD_BUG_ON(sizeof(struct mctp_skb_cb) > sizeof(skb->cb));	WARN_ON(cb->magic != 0x4d435450);	return cb;} /* If CONFIG_MCTP_FLOWS, we may add one of these as a SKB extension, * indicating the flow to the device driver. */struct mctp_flow {	struct mctp_sk_key *key;}; struct mctp_dst; /* 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. */struct mctp_route {	mctp_eid_t		min, max; 	unsigned char		type; 	unsigned int		mtu; 	enum {		MCTP_ROUTE_DIRECT,		MCTP_ROUTE_GATEWAY,	} dst_type;	union {		struct mctp_dev	*dev;		struct mctp_fq_addr gateway;	}; 	int			(*output)(struct mctp_dst *dst,					  struct sk_buff *skb); 	struct list_head	list;	refcount_t		refs;	struct rcu_head		rcu;}; /* Route lookup result: dst. Represents the results of a routing decision, * but is only held over the individual routing operation. * * Will typically be stored on the caller stack, and must be released after * usage. */struct mctp_dst {	struct mctp_dev *dev;	unsigned int mtu;	mctp_eid_t nexthop;	mctp_eid_t saddr; 	/* set for direct addressing */	unsigned char halen;	unsigned char haddr[MAX_ADDR_LEN]; 	int (*output)(struct mctp_dst *dst, struct sk_buff *skb);}; int mctp_dst_from_extaddr(struct mctp_dst *dst, struct net *net, int ifindex,			  unsigned char halen, const unsigned char *haddr); /* route interfaces */int mctp_route_lookup(struct net *net, unsigned int dnet,		      mctp_eid_t daddr, struct mctp_dst *dst); void mctp_dst_release(struct mctp_dst *dst); /* always takes ownership of skb */int mctp_local_output(struct sock *sk, struct mctp_dst *dst,		      struct sk_buff *skb, mctp_eid_t daddr, u8 req_tag); void mctp_key_unref(struct mctp_sk_key *key);struct mctp_sk_key *mctp_alloc_local_tag(struct mctp_sock *msk,					 unsigned int netid,					 mctp_eid_t local, mctp_eid_t peer,					 bool manual, u8 *tagp); /* 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_LENint 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); int mctp_device_init(void);void mctp_device_exit(void); /* MCTP IDs and Codes from DMTF specification * "DSP0239 Management Component Transport Protocol (MCTP) IDs and Codes" * https://www.dmtf.org/sites/default/files/standards/documents/DSP0239_1.11.1.pdf */enum mctp_phys_binding {	MCTP_PHYS_BINDING_UNSPEC	= 0x00,	MCTP_PHYS_BINDING_SMBUS		= 0x01,	MCTP_PHYS_BINDING_PCIE_VDM	= 0x02,	MCTP_PHYS_BINDING_USB		= 0x03,	MCTP_PHYS_BINDING_KCS		= 0x04,	MCTP_PHYS_BINDING_SERIAL	= 0x05,	MCTP_PHYS_BINDING_I3C		= 0x06,	MCTP_PHYS_BINDING_MMBI		= 0x07,	MCTP_PHYS_BINDING_PCC		= 0x08,	MCTP_PHYS_BINDING_UCIE		= 0x09,	MCTP_PHYS_BINDING_VENDOR	= 0xFF,}; #endif /* __NET_MCTP_H */