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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 | ||
889b7da2 JK |
39 | #define MCTP_HEADER_MAXLEN 4 |
40 | ||
03f2bbc4 MJ |
41 | #define MCTP_INITIAL_DEFAULT_NET 1 |
42 | ||
583be982 JK |
43 | static inline bool mctp_address_ok(mctp_eid_t eid) |
44 | { | |
45 | return eid >= 8 && eid < 255; | |
46 | } | |
47 | ||
48 | static inline struct mctp_hdr *mctp_hdr(struct sk_buff *skb) | |
49 | { | |
50 | return (struct mctp_hdr *)skb_network_header(skb); | |
51 | } | |
52 | ||
833ef3b9 JK |
53 | /* socket implementation */ |
54 | struct mctp_sock { | |
55 | struct sock sk; | |
56 | ||
57 | /* bind() params */ | |
b416beb2 | 58 | unsigned int bind_net; |
833ef3b9 JK |
59 | mctp_eid_t bind_addr; |
60 | __u8 bind_type; | |
61 | ||
99ce45d5 JK |
62 | /* sendmsg()/recvmsg() uses struct sockaddr_mctp_ext */ |
63 | bool addr_ext; | |
64 | ||
833ef3b9 JK |
65 | /* list of mctp_sk_key, for incoming tag lookup. updates protected |
66 | * by sk->net->keys_lock | |
67 | */ | |
68 | struct hlist_head keys; | |
7b14e15a JK |
69 | |
70 | /* mechanism for expiring allocated keys; will release an allocated | |
71 | * tag, and any netdev state for a request/response pairing | |
72 | */ | |
73 | struct timer_list key_expiry; | |
833ef3b9 JK |
74 | }; |
75 | ||
76 | /* Key for matching incoming packets to sockets or reassembly contexts. | |
77 | * Packets are matched on (src,dest,tag). | |
78 | * | |
73c61845 | 79 | * Lifetime / locking requirements: |
833ef3b9 | 80 | * |
73c61845 JK |
81 | * - individual key data (ie, the struct itself) is protected by key->lock; |
82 | * changes must be made with that lock held. | |
83 | * | |
84 | * - the lookup fields: peer_addr, local_addr and tag are set before the | |
85 | * key is added to lookup lists, and never updated. | |
86 | * | |
87 | * - A ref to the key must be held (throuh key->refs) if a pointer to the | |
88 | * key is to be accessed after key->lock is released. | |
833ef3b9 JK |
89 | * |
90 | * - a mctp_sk_key contains a reference to a struct sock; this is valid | |
91 | * for the life of the key. On sock destruction (through unhash), the key is | |
73c61845 | 92 | * removed from lists (see below), and marked invalid. |
833ef3b9 JK |
93 | * |
94 | * - these mctp_sk_keys appear on two lists: | |
95 | * 1) the struct mctp_sock->keys list | |
96 | * 2) the struct netns_mctp->keys list | |
97 | * | |
73c61845 JK |
98 | * presences on these lists requires a (single) refcount to be held; both |
99 | * lists are updated as a single operation. | |
100 | * | |
101 | * Updates and lookups in either list are performed under the | |
102 | * netns_mctp->keys lock. Lookup functions will need to lock the key and | |
103 | * take a reference before unlocking the keys_lock. Consequently, the list's | |
104 | * keys_lock *cannot* be acquired with the individual key->lock held. | |
833ef3b9 | 105 | * |
4a992bbd | 106 | * - a key may have a sk_buff attached as part of an in-progress message |
73c61845 JK |
107 | * reassembly (->reasm_head). The reasm data is protected by the individual |
108 | * key->lock. | |
4a992bbd JK |
109 | * |
110 | * - there are two destruction paths for a mctp_sk_key: | |
111 | * | |
112 | * - through socket unhash (see mctp_sk_unhash). This performs the list | |
113 | * removal under keys_lock. | |
114 | * | |
115 | * - where a key is established to receive a reply message: after receiving | |
116 | * the (complete) reply, or during reassembly errors. Here, we clean up | |
117 | * the reassembly context (marking reasm_dead, to prevent another from | |
118 | * starting), and remove the socket from the netns & socket lists. | |
7b14e15a JK |
119 | * |
120 | * - through an expiry timeout, on a per-socket timer | |
833ef3b9 JK |
121 | */ |
122 | struct mctp_sk_key { | |
123 | mctp_eid_t peer_addr; | |
124 | mctp_eid_t local_addr; | |
125 | __u8 tag; /* incoming tag match; invert TO for local */ | |
126 | ||
127 | /* we hold a ref to sk when set */ | |
128 | struct sock *sk; | |
129 | ||
130 | /* routing lookup list */ | |
131 | struct hlist_node hlist; | |
132 | ||
133 | /* per-socket list */ | |
134 | struct hlist_node sklist; | |
135 | ||
73c61845 JK |
136 | /* lock protects against concurrent updates to the reassembly and |
137 | * expiry data below. | |
138 | */ | |
139 | spinlock_t lock; | |
140 | ||
141 | /* Keys are referenced during the output path, which may sleep */ | |
142 | refcount_t refs; | |
143 | ||
4a992bbd | 144 | /* incoming fragment reassembly context */ |
4a992bbd JK |
145 | struct sk_buff *reasm_head; |
146 | struct sk_buff **reasm_tailp; | |
147 | bool reasm_dead; | |
148 | u8 last_seq; | |
149 | ||
73c61845 JK |
150 | /* key validity */ |
151 | bool valid; | |
7b14e15a JK |
152 | |
153 | /* expiry timeout; valid (above) cleared on expiry */ | |
154 | unsigned long expiry; | |
67737c45 JK |
155 | |
156 | /* free to use for device flow state tracking. Initialised to | |
157 | * zero on initial key creation | |
158 | */ | |
159 | unsigned long dev_flow_state; | |
160 | struct mctp_dev *dev; | |
833ef3b9 JK |
161 | }; |
162 | ||
889b7da2 JK |
163 | struct mctp_skb_cb { |
164 | unsigned int magic; | |
165 | unsigned int net; | |
99ce45d5 | 166 | int ifindex; /* extended/direct addressing if set */ |
889b7da2 | 167 | mctp_eid_t src; |
99ce45d5 JK |
168 | unsigned char halen; |
169 | unsigned char haddr[MAX_ADDR_LEN]; | |
889b7da2 JK |
170 | }; |
171 | ||
172 | /* skb control-block accessors with a little extra debugging for initial | |
173 | * development. | |
174 | * | |
175 | * TODO: remove checks & mctp_skb_cb->magic; replace callers of __mctp_cb | |
176 | * with mctp_cb(). | |
177 | * | |
178 | * __mctp_cb() is only for the initial ingress code; we should see ->magic set | |
179 | * at all times after this. | |
180 | */ | |
181 | static inline struct mctp_skb_cb *__mctp_cb(struct sk_buff *skb) | |
182 | { | |
183 | struct mctp_skb_cb *cb = (void *)skb->cb; | |
184 | ||
185 | cb->magic = 0x4d435450; | |
186 | return cb; | |
187 | } | |
188 | ||
189 | static inline struct mctp_skb_cb *mctp_cb(struct sk_buff *skb) | |
190 | { | |
191 | struct mctp_skb_cb *cb = (void *)skb->cb; | |
192 | ||
99ce45d5 | 193 | BUILD_BUG_ON(sizeof(struct mctp_skb_cb) > sizeof(skb->cb)); |
889b7da2 JK |
194 | WARN_ON(cb->magic != 0x4d435450); |
195 | return (void *)(skb->cb); | |
196 | } | |
197 | ||
78476d31 JK |
198 | /* If CONFIG_MCTP_FLOWS, we may add one of these as a SKB extension, |
199 | * indicating the flow to the device driver. | |
200 | */ | |
201 | struct mctp_flow { | |
202 | struct mctp_sk_key *key; | |
203 | }; | |
204 | ||
889b7da2 JK |
205 | /* Route definition. |
206 | * | |
207 | * These are held in the pernet->mctp.routes list, with RCU protection for | |
208 | * removed routes. We hold a reference to the netdev; routes need to be | |
209 | * dropped on NETDEV_UNREGISTER events. | |
210 | * | |
211 | * Updates to the route table are performed under rtnl; all reads under RCU, | |
212 | * so routes cannot be referenced over a RCU grace period. Specifically: A | |
99ce45d5 | 213 | * caller cannot block between mctp_route_lookup and mctp_route_release() |
889b7da2 JK |
214 | */ |
215 | struct mctp_route { | |
216 | mctp_eid_t min, max; | |
217 | ||
218 | struct mctp_dev *dev; | |
219 | unsigned int mtu; | |
83f0a0b7 | 220 | unsigned char type; |
889b7da2 JK |
221 | int (*output)(struct mctp_route *route, |
222 | struct sk_buff *skb); | |
223 | ||
224 | struct list_head list; | |
225 | refcount_t refs; | |
226 | struct rcu_head rcu; | |
227 | }; | |
228 | ||
229 | /* route interfaces */ | |
230 | struct mctp_route *mctp_route_lookup(struct net *net, unsigned int dnet, | |
231 | mctp_eid_t daddr); | |
232 | ||
889b7da2 JK |
233 | int mctp_local_output(struct sock *sk, struct mctp_route *rt, |
234 | struct sk_buff *skb, mctp_eid_t daddr, u8 req_tag); | |
73c61845 JK |
235 | |
236 | void mctp_key_unref(struct mctp_sk_key *key); | |
889b7da2 JK |
237 | |
238 | /* routing <--> device interface */ | |
06d2f4c5 MJ |
239 | unsigned int mctp_default_net(struct net *net); |
240 | int mctp_default_net_set(struct net *net, unsigned int index); | |
889b7da2 JK |
241 | int mctp_route_add_local(struct mctp_dev *mdev, mctp_eid_t addr); |
242 | int mctp_route_remove_local(struct mctp_dev *mdev, mctp_eid_t addr); | |
243 | void mctp_route_remove_dev(struct mctp_dev *mdev); | |
244 | ||
4d8b9319 MJ |
245 | /* neighbour definitions */ |
246 | enum mctp_neigh_source { | |
247 | MCTP_NEIGH_STATIC, | |
248 | MCTP_NEIGH_DISCOVER, | |
249 | }; | |
250 | ||
251 | struct mctp_neigh { | |
252 | struct mctp_dev *dev; | |
253 | mctp_eid_t eid; | |
254 | enum mctp_neigh_source source; | |
255 | ||
256 | unsigned char ha[MAX_ADDR_LEN]; | |
257 | ||
258 | struct list_head list; | |
259 | struct rcu_head rcu; | |
260 | }; | |
261 | ||
262 | int mctp_neigh_init(void); | |
263 | void mctp_neigh_exit(void); | |
264 | ||
265 | // ret_hwaddr may be NULL, otherwise must have space for MAX_ADDR_LEN | |
266 | int mctp_neigh_lookup(struct mctp_dev *dev, mctp_eid_t eid, | |
267 | void *ret_hwaddr); | |
268 | void mctp_neigh_remove_dev(struct mctp_dev *mdev); | |
269 | ||
889b7da2 JK |
270 | int mctp_routes_init(void); |
271 | void mctp_routes_exit(void); | |
272 | ||
583be982 JK |
273 | void mctp_device_init(void); |
274 | void mctp_device_exit(void); | |
275 | ||
2c8e2e9a | 276 | #endif /* __NET_MCTP_H */ |