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> 13 #include <linux/mctp.h> 14 #include <linux/netdevice.h> 15 #include <net/net_namespace.h> 16 #include <net/sock.h> 17 18 /* MCTP packet definitions */ 19 struct mctp_hdr { 20 u8 ver; 21 u8 dest; 22 u8 src; 23 u8 flags_seq_tag; 24 }; 25 26 #define MCTP_VER_MIN 1 27 #define MCTP_VER_MAX 1 28 29 /* Definitions for flags_seq_tag field */ 30 #define MCTP_HDR_FLAG_SOM BIT(7) 31 #define MCTP_HDR_FLAG_EOM BIT(6) 32 #define MCTP_HDR_FLAG_TO BIT(3) 33 #define MCTP_HDR_FLAGS GENMASK(5, 3) 34 #define MCTP_HDR_SEQ_SHIFT 4 35 #define MCTP_HDR_SEQ_MASK GENMASK(1, 0) 36 #define MCTP_HDR_TAG_SHIFT 0 37 #define MCTP_HDR_TAG_MASK GENMASK(2, 0) 38 39 #define MCTP_INITIAL_DEFAULT_NET 1 40 41 static inline bool mctp_address_unicast(mctp_eid_t eid) 42 { 43 return eid >= 8 && eid < 255; 44 } 45 46 static inline bool mctp_address_broadcast(mctp_eid_t eid) 47 { 48 return eid == 255; 49 } 50 51 static inline bool mctp_address_null(mctp_eid_t eid) 52 { 53 return eid == 0; 54 } 55 56 static inline bool mctp_address_matches(mctp_eid_t match, mctp_eid_t eid) 57 { 58 return match == eid || match == MCTP_ADDR_ANY; 59 } 60 61 static inline struct mctp_hdr *mctp_hdr(struct sk_buff *skb) 62 { 63 return (struct mctp_hdr *)skb_network_header(skb); 64 } 65 66 /* socket implementation */ 67 struct mctp_sock { 68 struct sock sk; 69 70 /* bind() params */ 71 unsigned int bind_net; 72 mctp_eid_t bind_local_addr; 73 mctp_eid_t bind_peer_addr; 74 unsigned int bind_peer_net; 75 bool bind_peer_set; 76 __u8 bind_type; 77 78 /* sendmsg()/recvmsg() uses struct sockaddr_mctp_ext */ 79 bool addr_ext; 80 81 /* list of mctp_sk_key, for incoming tag lookup. updates protected 82 * by sk->net->keys_lock 83 */ 84 struct hlist_head keys; 85 86 /* mechanism for expiring allocated keys; will release an allocated 87 * tag, and any netdev state for a request/response pairing 88 */ 89 struct timer_list key_expiry; 90 }; 91 92 /* Key for matching incoming packets to sockets or reassembly contexts. 93 * Packets are matched on (peer EID, local EID, tag). 94 * 95 * Lifetime / locking requirements: 96 * 97 * - individual key data (ie, the struct itself) is protected by key->lock; 98 * changes must be made with that lock held. 99 * 100 * - the lookup fields: peer_addr, local_addr and tag are set before the 101 * key is added to lookup lists, and never updated. 102 * 103 * - A ref to the key must be held (throuh key->refs) if a pointer to the 104 * key is to be accessed after key->lock is released. 105 * 106 * - a mctp_sk_key contains a reference to a struct sock; this is valid 107 * for the life of the key. On sock destruction (through unhash), the key is 108 * removed from lists (see below), and marked invalid. 109 * 110 * - these mctp_sk_keys appear on two lists: 111 * 1) the struct mctp_sock->keys list 112 * 2) the struct netns_mctp->keys list 113 * 114 * presences on these lists requires a (single) refcount to be held; both 115 * lists are updated as a single operation. 116 * 117 * Updates and lookups in either list are performed under the 118 * netns_mctp->keys lock. Lookup functions will need to lock the key and 119 * take a reference before unlocking the keys_lock. Consequently, the list's 120 * keys_lock *cannot* be acquired with the individual key->lock held. 121 * 122 * - a key may have a sk_buff attached as part of an in-progress message 123 * reassembly (->reasm_head). The reasm data is protected by the individual 124 * key->lock. 125 * 126 * - there are two destruction paths for a mctp_sk_key: 127 * 128 * - through socket unhash (see mctp_sk_unhash). This performs the list 129 * removal under keys_lock. 130 * 131 * - where a key is established to receive a reply message: after receiving 132 * the (complete) reply, or during reassembly errors. Here, we clean up 133 * the reassembly context (marking reasm_dead, to prevent another from 134 * starting), and remove the socket from the netns & socket lists. 135 * 136 * - through an expiry timeout, on a per-socket timer 137 */ 138 struct mctp_sk_key { 139 unsigned int net; 140 mctp_eid_t peer_addr; 141 mctp_eid_t local_addr; /* MCTP_ADDR_ANY for local owned tags */ 142 __u8 tag; /* incoming tag match; invert TO for local */ 143 144 /* we hold a ref to sk when set */ 145 struct sock *sk; 146 147 /* routing lookup list */ 148 struct hlist_node hlist; 149 150 /* per-socket list */ 151 struct hlist_node sklist; 152 153 /* lock protects against concurrent updates to the reassembly and 154 * expiry data below. 155 */ 156 spinlock_t lock; 157 158 /* Keys are referenced during the output path, which may sleep */ 159 refcount_t refs; 160 161 /* incoming fragment reassembly context */ 162 struct sk_buff *reasm_head; 163 struct sk_buff **reasm_tailp; 164 bool reasm_dead; 165 u8 last_seq; 166 167 /* key validity */ 168 bool valid; 169 170 /* expiry timeout; valid (above) cleared on expiry */ 171 unsigned long expiry; 172 173 /* free to use for device flow state tracking. Initialised to 174 * zero on initial key creation 175 */ 176 unsigned long dev_flow_state; 177 struct mctp_dev *dev; 178 179 /* a tag allocated with SIOCMCTPALLOCTAG ioctl will not expire 180 * automatically on timeout or response, instead SIOCMCTPDROPTAG 181 * is used. 182 */ 183 bool manual_alloc; 184 }; 185 186 struct mctp_skb_cb { 187 unsigned int magic; 188 unsigned int net; 189 /* fields below provide extended addressing for ingress to recvmsg() */ 190 int ifindex; 191 unsigned char halen; 192 unsigned char haddr[MAX_ADDR_LEN]; 193 }; 194 195 /* skb control-block accessors with a little extra debugging for initial 196 * development. 197 * 198 * TODO: remove checks & mctp_skb_cb->magic; replace callers of __mctp_cb 199 * with mctp_cb(). 200 * 201 * __mctp_cb() is only for the initial ingress code; we should see ->magic set 202 * at all times after this. 203 */ 204 static inline struct mctp_skb_cb *__mctp_cb(struct sk_buff *skb) 205 { 206 struct mctp_skb_cb *cb = (void *)skb->cb; 207 208 cb->magic = 0x4d435450; 209 return cb; 210 } 211 212 static inline struct mctp_skb_cb *mctp_cb(struct sk_buff *skb) 213 { 214 struct mctp_skb_cb *cb = (void *)skb->cb; 215 216 BUILD_BUG_ON(sizeof(struct mctp_skb_cb) > sizeof(skb->cb)); 217 WARN_ON(cb->magic != 0x4d435450); 218 return cb; 219 } 220 221 /* If CONFIG_MCTP_FLOWS, we may add one of these as a SKB extension, 222 * indicating the flow to the device driver. 223 */ 224 struct mctp_flow { 225 struct mctp_sk_key *key; 226 }; 227 228 struct mctp_dst; 229 230 /* Route definition. 231 * 232 * These are held in the pernet->mctp.routes list, with RCU protection for 233 * removed routes. We hold a reference to the netdev; routes need to be 234 * dropped on NETDEV_UNREGISTER events. 235 * 236 * Updates to the route table are performed under rtnl; all reads under RCU, 237 * so routes cannot be referenced over a RCU grace period. 238 */ 239 struct mctp_route { 240 mctp_eid_t min, max; 241 242 unsigned char type; 243 244 unsigned int mtu; 245 246 enum { 247 MCTP_ROUTE_DIRECT, 248 MCTP_ROUTE_GATEWAY, 249 } dst_type; 250 union { 251 struct mctp_dev *dev; 252 struct mctp_fq_addr gateway; 253 }; 254 255 int (*output)(struct mctp_dst *dst, 256 struct sk_buff *skb); 257 258 struct list_head list; 259 refcount_t refs; 260 struct rcu_head rcu; 261 }; 262 263 /* Route lookup result: dst. Represents the results of a routing decision, 264 * but is only held over the individual routing operation. 265 * 266 * Will typically be stored on the caller stack, and must be released after 267 * usage. 268 */ 269 struct mctp_dst { 270 struct mctp_dev *dev; 271 unsigned int mtu; 272 mctp_eid_t nexthop; 273 274 /* set for direct addressing */ 275 unsigned char halen; 276 unsigned char haddr[MAX_ADDR_LEN]; 277 278 int (*output)(struct mctp_dst *dst, struct sk_buff *skb); 279 }; 280 281 int mctp_dst_from_extaddr(struct mctp_dst *dst, struct net *net, int ifindex, 282 unsigned char halen, const unsigned char *haddr); 283 284 /* route interfaces */ 285 int mctp_route_lookup(struct net *net, unsigned int dnet, 286 mctp_eid_t daddr, struct mctp_dst *dst); 287 288 void mctp_dst_release(struct mctp_dst *dst); 289 290 /* always takes ownership of skb */ 291 int mctp_local_output(struct sock *sk, struct mctp_dst *dst, 292 struct sk_buff *skb, mctp_eid_t daddr, u8 req_tag); 293 294 void mctp_key_unref(struct mctp_sk_key *key); 295 struct mctp_sk_key *mctp_alloc_local_tag(struct mctp_sock *msk, 296 unsigned int netid, 297 mctp_eid_t local, mctp_eid_t peer, 298 bool manual, u8 *tagp); 299 300 /* routing <--> device interface */ 301 unsigned int mctp_default_net(struct net *net); 302 int mctp_default_net_set(struct net *net, unsigned int index); 303 int mctp_route_add_local(struct mctp_dev *mdev, mctp_eid_t addr); 304 int mctp_route_remove_local(struct mctp_dev *mdev, mctp_eid_t addr); 305 void mctp_route_remove_dev(struct mctp_dev *mdev); 306 307 /* neighbour definitions */ 308 enum mctp_neigh_source { 309 MCTP_NEIGH_STATIC, 310 MCTP_NEIGH_DISCOVER, 311 }; 312 313 struct mctp_neigh { 314 struct mctp_dev *dev; 315 mctp_eid_t eid; 316 enum mctp_neigh_source source; 317 318 unsigned char ha[MAX_ADDR_LEN]; 319 320 struct list_head list; 321 struct rcu_head rcu; 322 }; 323 324 int mctp_neigh_init(void); 325 void mctp_neigh_exit(void); 326 327 // ret_hwaddr may be NULL, otherwise must have space for MAX_ADDR_LEN 328 int mctp_neigh_lookup(struct mctp_dev *dev, mctp_eid_t eid, 329 void *ret_hwaddr); 330 void mctp_neigh_remove_dev(struct mctp_dev *mdev); 331 332 int mctp_routes_init(void); 333 void mctp_routes_exit(void); 334 335 int mctp_device_init(void); 336 void mctp_device_exit(void); 337 338 /* MCTP IDs and Codes from DMTF specification 339 * "DSP0239 Management Component Transport Protocol (MCTP) IDs and Codes" 340 * https://www.dmtf.org/sites/default/files/standards/documents/DSP0239_1.11.1.pdf 341 */ 342 enum mctp_phys_binding { 343 MCTP_PHYS_BINDING_UNSPEC = 0x00, 344 MCTP_PHYS_BINDING_SMBUS = 0x01, 345 MCTP_PHYS_BINDING_PCIE_VDM = 0x02, 346 MCTP_PHYS_BINDING_USB = 0x03, 347 MCTP_PHYS_BINDING_KCS = 0x04, 348 MCTP_PHYS_BINDING_SERIAL = 0x05, 349 MCTP_PHYS_BINDING_I3C = 0x06, 350 MCTP_PHYS_BINDING_MMBI = 0x07, 351 MCTP_PHYS_BINDING_PCC = 0x08, 352 MCTP_PHYS_BINDING_UCIE = 0x09, 353 MCTP_PHYS_BINDING_VENDOR = 0xFF, 354 }; 355 356 #endif /* __NET_MCTP_H */ 357