/* 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 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; /* 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_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); 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 */
