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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> |
99ce45d5 | 14 | #include <linux/netdevice.h> |
889b7da2 | 15 | #include <net/net_namespace.h> |
833ef3b9 | 16 | #include <net/sock.h> |
2c8e2e9a JK |
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 | ||
03f2bbc4 MJ |
39 | #define MCTP_INITIAL_DEFAULT_NET 1 |
40 | ||
cb196b72 | 41 | static inline bool mctp_address_unicast(mctp_eid_t eid) |
583be982 JK |
42 | { |
43 | return eid >= 8 && eid < 255; | |
44 | } | |
45 | ||
cb196b72 JK |
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 | ||
8069b22d JK |
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 | ||
583be982 JK |
61 | static inline struct mctp_hdr *mctp_hdr(struct sk_buff *skb) |
62 | { | |
63 | return (struct mctp_hdr *)skb_network_header(skb); | |
64 | } | |
65 | ||
833ef3b9 JK |
66 | /* socket implementation */ |
67 | struct mctp_sock { | |
68 | struct sock sk; | |
69 | ||
70 | /* bind() params */ | |
b416beb2 | 71 | unsigned int bind_net; |
833ef3b9 JK |
72 | mctp_eid_t bind_addr; |
73 | __u8 bind_type; | |
74 | ||
99ce45d5 JK |
75 | /* sendmsg()/recvmsg() uses struct sockaddr_mctp_ext */ |
76 | bool addr_ext; | |
77 | ||
833ef3b9 JK |
78 | /* list of mctp_sk_key, for incoming tag lookup. updates protected |
79 | * by sk->net->keys_lock | |
80 | */ | |
81 | struct hlist_head keys; | |
7b14e15a JK |
82 | |
83 | /* mechanism for expiring allocated keys; will release an allocated | |
84 | * tag, and any netdev state for a request/response pairing | |
85 | */ | |
86 | struct timer_list key_expiry; | |
833ef3b9 JK |
87 | }; |
88 | ||
89 | /* Key for matching incoming packets to sockets or reassembly contexts. | |
90 | * Packets are matched on (src,dest,tag). | |
91 | * | |
73c61845 | 92 | * Lifetime / locking requirements: |
833ef3b9 | 93 | * |
73c61845 JK |
94 | * - individual key data (ie, the struct itself) is protected by key->lock; |
95 | * changes must be made with that lock held. | |
96 | * | |
97 | * - the lookup fields: peer_addr, local_addr and tag are set before the | |
98 | * key is added to lookup lists, and never updated. | |
99 | * | |
100 | * - A ref to the key must be held (throuh key->refs) if a pointer to the | |
101 | * key is to be accessed after key->lock is released. | |
833ef3b9 JK |
102 | * |
103 | * - a mctp_sk_key contains a reference to a struct sock; this is valid | |
104 | * for the life of the key. On sock destruction (through unhash), the key is | |
73c61845 | 105 | * removed from lists (see below), and marked invalid. |
833ef3b9 JK |
106 | * |
107 | * - these mctp_sk_keys appear on two lists: | |
108 | * 1) the struct mctp_sock->keys list | |
109 | * 2) the struct netns_mctp->keys list | |
110 | * | |
73c61845 JK |
111 | * presences on these lists requires a (single) refcount to be held; both |
112 | * lists are updated as a single operation. | |
113 | * | |
114 | * Updates and lookups in either list are performed under the | |
115 | * netns_mctp->keys lock. Lookup functions will need to lock the key and | |
116 | * take a reference before unlocking the keys_lock. Consequently, the list's | |
117 | * keys_lock *cannot* be acquired with the individual key->lock held. | |
833ef3b9 | 118 | * |
4a992bbd | 119 | * - a key may have a sk_buff attached as part of an in-progress message |
73c61845 JK |
120 | * reassembly (->reasm_head). The reasm data is protected by the individual |
121 | * key->lock. | |
4a992bbd JK |
122 | * |
123 | * - there are two destruction paths for a mctp_sk_key: | |
124 | * | |
125 | * - through socket unhash (see mctp_sk_unhash). This performs the list | |
126 | * removal under keys_lock. | |
127 | * | |
128 | * - where a key is established to receive a reply message: after receiving | |
129 | * the (complete) reply, or during reassembly errors. Here, we clean up | |
130 | * the reassembly context (marking reasm_dead, to prevent another from | |
131 | * starting), and remove the socket from the netns & socket lists. | |
7b14e15a JK |
132 | * |
133 | * - through an expiry timeout, on a per-socket timer | |
833ef3b9 JK |
134 | */ |
135 | struct mctp_sk_key { | |
136 | mctp_eid_t peer_addr; | |
63ed1aab | 137 | mctp_eid_t local_addr; /* MCTP_ADDR_ANY for local owned tags */ |
833ef3b9 JK |
138 | __u8 tag; /* incoming tag match; invert TO for local */ |
139 | ||
140 | /* we hold a ref to sk when set */ | |
141 | struct sock *sk; | |
142 | ||
143 | /* routing lookup list */ | |
144 | struct hlist_node hlist; | |
145 | ||
146 | /* per-socket list */ | |
147 | struct hlist_node sklist; | |
148 | ||
73c61845 JK |
149 | /* lock protects against concurrent updates to the reassembly and |
150 | * expiry data below. | |
151 | */ | |
152 | spinlock_t lock; | |
153 | ||
154 | /* Keys are referenced during the output path, which may sleep */ | |
155 | refcount_t refs; | |
156 | ||
4a992bbd | 157 | /* incoming fragment reassembly context */ |
4a992bbd JK |
158 | struct sk_buff *reasm_head; |
159 | struct sk_buff **reasm_tailp; | |
160 | bool reasm_dead; | |
161 | u8 last_seq; | |
162 | ||
73c61845 JK |
163 | /* key validity */ |
164 | bool valid; | |
7b14e15a JK |
165 | |
166 | /* expiry timeout; valid (above) cleared on expiry */ | |
167 | unsigned long expiry; | |
67737c45 JK |
168 | |
169 | /* free to use for device flow state tracking. Initialised to | |
170 | * zero on initial key creation | |
171 | */ | |
172 | unsigned long dev_flow_state; | |
173 | struct mctp_dev *dev; | |
63ed1aab MJ |
174 | |
175 | /* a tag allocated with SIOCMCTPALLOCTAG ioctl will not expire | |
176 | * automatically on timeout or response, instead SIOCMCTPDROPTAG | |
177 | * is used. | |
178 | */ | |
179 | bool manual_alloc; | |
833ef3b9 JK |
180 | }; |
181 | ||
889b7da2 JK |
182 | struct mctp_skb_cb { |
183 | unsigned int magic; | |
184 | unsigned int net; | |
99ce45d5 | 185 | int ifindex; /* extended/direct addressing if set */ |
889b7da2 | 186 | mctp_eid_t src; |
99ce45d5 JK |
187 | unsigned char halen; |
188 | unsigned char haddr[MAX_ADDR_LEN]; | |
889b7da2 JK |
189 | }; |
190 | ||
191 | /* skb control-block accessors with a little extra debugging for initial | |
192 | * development. | |
193 | * | |
194 | * TODO: remove checks & mctp_skb_cb->magic; replace callers of __mctp_cb | |
195 | * with mctp_cb(). | |
196 | * | |
197 | * __mctp_cb() is only for the initial ingress code; we should see ->magic set | |
198 | * at all times after this. | |
199 | */ | |
200 | static inline struct mctp_skb_cb *__mctp_cb(struct sk_buff *skb) | |
201 | { | |
202 | struct mctp_skb_cb *cb = (void *)skb->cb; | |
203 | ||
204 | cb->magic = 0x4d435450; | |
205 | return cb; | |
206 | } | |
207 | ||
208 | static inline struct mctp_skb_cb *mctp_cb(struct sk_buff *skb) | |
209 | { | |
210 | struct mctp_skb_cb *cb = (void *)skb->cb; | |
211 | ||
99ce45d5 | 212 | BUILD_BUG_ON(sizeof(struct mctp_skb_cb) > sizeof(skb->cb)); |
889b7da2 JK |
213 | WARN_ON(cb->magic != 0x4d435450); |
214 | return (void *)(skb->cb); | |
215 | } | |
216 | ||
78476d31 JK |
217 | /* If CONFIG_MCTP_FLOWS, we may add one of these as a SKB extension, |
218 | * indicating the flow to the device driver. | |
219 | */ | |
220 | struct mctp_flow { | |
221 | struct mctp_sk_key *key; | |
222 | }; | |
223 | ||
889b7da2 JK |
224 | /* Route definition. |
225 | * | |
226 | * These are held in the pernet->mctp.routes list, with RCU protection for | |
227 | * removed routes. We hold a reference to the netdev; routes need to be | |
228 | * dropped on NETDEV_UNREGISTER events. | |
229 | * | |
230 | * Updates to the route table are performed under rtnl; all reads under RCU, | |
231 | * so routes cannot be referenced over a RCU grace period. Specifically: A | |
99ce45d5 | 232 | * caller cannot block between mctp_route_lookup and mctp_route_release() |
889b7da2 JK |
233 | */ |
234 | struct mctp_route { | |
235 | mctp_eid_t min, max; | |
236 | ||
83f0a0b7 | 237 | unsigned char type; |
066768b7 CJ |
238 | unsigned int mtu; |
239 | struct mctp_dev *dev; | |
889b7da2 JK |
240 | int (*output)(struct mctp_route *route, |
241 | struct sk_buff *skb); | |
242 | ||
243 | struct list_head list; | |
244 | refcount_t refs; | |
245 | struct rcu_head rcu; | |
246 | }; | |
247 | ||
248 | /* route interfaces */ | |
249 | struct mctp_route *mctp_route_lookup(struct net *net, unsigned int dnet, | |
250 | mctp_eid_t daddr); | |
251 | ||
889b7da2 JK |
252 | int mctp_local_output(struct sock *sk, struct mctp_route *rt, |
253 | struct sk_buff *skb, mctp_eid_t daddr, u8 req_tag); | |
73c61845 JK |
254 | |
255 | void mctp_key_unref(struct mctp_sk_key *key); | |
63ed1aab MJ |
256 | struct mctp_sk_key *mctp_alloc_local_tag(struct mctp_sock *msk, |
257 | mctp_eid_t daddr, mctp_eid_t saddr, | |
258 | bool manual, u8 *tagp); | |
889b7da2 JK |
259 | |
260 | /* routing <--> device interface */ | |
06d2f4c5 MJ |
261 | unsigned int mctp_default_net(struct net *net); |
262 | int mctp_default_net_set(struct net *net, unsigned int index); | |
889b7da2 JK |
263 | int mctp_route_add_local(struct mctp_dev *mdev, mctp_eid_t addr); |
264 | int mctp_route_remove_local(struct mctp_dev *mdev, mctp_eid_t addr); | |
265 | void mctp_route_remove_dev(struct mctp_dev *mdev); | |
266 | ||
4d8b9319 MJ |
267 | /* neighbour definitions */ |
268 | enum mctp_neigh_source { | |
269 | MCTP_NEIGH_STATIC, | |
270 | MCTP_NEIGH_DISCOVER, | |
271 | }; | |
272 | ||
273 | struct mctp_neigh { | |
274 | struct mctp_dev *dev; | |
275 | mctp_eid_t eid; | |
276 | enum mctp_neigh_source source; | |
277 | ||
278 | unsigned char ha[MAX_ADDR_LEN]; | |
279 | ||
280 | struct list_head list; | |
281 | struct rcu_head rcu; | |
282 | }; | |
283 | ||
284 | int mctp_neigh_init(void); | |
285 | void mctp_neigh_exit(void); | |
286 | ||
287 | // ret_hwaddr may be NULL, otherwise must have space for MAX_ADDR_LEN | |
288 | int mctp_neigh_lookup(struct mctp_dev *dev, mctp_eid_t eid, | |
289 | void *ret_hwaddr); | |
290 | void mctp_neigh_remove_dev(struct mctp_dev *mdev); | |
291 | ||
889b7da2 JK |
292 | int mctp_routes_init(void); |
293 | void mctp_routes_exit(void); | |
294 | ||
583be982 JK |
295 | void mctp_device_init(void); |
296 | void mctp_device_exit(void); | |
297 | ||
2c8e2e9a | 298 | #endif /* __NET_MCTP_H */ |