1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
|
/* 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 <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_HEADER_MAXLEN 4
#define MCTP_INITIAL_DEFAULT_NET 1
static inline bool mctp_address_ok(mctp_eid_t eid)
{
return eid >= 8 && eid < 255;
}
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_addr;
__u8 bind_type;
/* list of mctp_sk_key, for incoming tag lookup. updates protected
* by sk->net->keys_lock
*/
struct hlist_head keys;
};
/* Key for matching incoming packets to sockets or reassembly contexts.
* Packets are matched on (src,dest,tag).
*
* Lifetime requirements:
*
* - keys are free()ed via RCU
*
* - 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 will not be observable after a RCU
* grace period.
*
* any RX occurring within that grace period may still queue to the socket,
* but will hit the SOCK_DEAD case before the socket is freed.
*
* - these mctp_sk_keys appear on two lists:
* 1) the struct mctp_sock->keys list
* 2) the struct netns_mctp->keys list
*
* updates to either list are performed under the netns_mctp->keys
* lock.
*
* - a key may have a sk_buff attached as part of an in-progress message
* reassembly (->reasm_head). The reassembly context is protected by
* reasm_lock, which may be acquired with the keys lock (above) held, if
* necessary. Consequently, keys lock *cannot* be acquired with the
* reasm_lock held.
*
* - 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.
*/
struct mctp_sk_key {
mctp_eid_t peer_addr;
mctp_eid_t local_addr;
__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;
/* incoming fragment reassembly context */
spinlock_t reasm_lock;
struct sk_buff *reasm_head;
struct sk_buff **reasm_tailp;
bool reasm_dead;
u8 last_seq;
struct rcu_head rcu;
};
struct mctp_skb_cb {
unsigned int magic;
unsigned int net;
mctp_eid_t src;
};
/* 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;
WARN_ON(cb->magic != 0x4d435450);
return (void *)(skb->cb);
}
/* 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. Specifically: A
* caller cannot block between mctp_route_lookup and passing the route to
* mctp_do_route.
*/
struct mctp_route {
mctp_eid_t min, max;
struct mctp_dev *dev;
unsigned int mtu;
unsigned char type;
int (*output)(struct mctp_route *route,
struct sk_buff *skb);
struct list_head list;
refcount_t refs;
struct rcu_head rcu;
};
/* route interfaces */
struct mctp_route *mctp_route_lookup(struct net *net, unsigned int dnet,
mctp_eid_t daddr);
int mctp_do_route(struct mctp_route *rt, struct sk_buff *skb);
int mctp_local_output(struct sock *sk, struct mctp_route *rt,
struct sk_buff *skb, mctp_eid_t daddr, u8 req_tag);
/* 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);
void mctp_device_init(void);
void mctp_device_exit(void);
#endif /* __NET_MCTP_H */
|
