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
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* Pluggable TCP upper layer protocol support.
*
* Copyright (c) 2016-2017, Mellanox Technologies. All rights reserved.
* Copyright (c) 2016-2017, Dave Watson <davejwatson@fb.com>. All rights reserved.
*
*/
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/types.h>
#include <linux/list.h>
#include <linux/gfp.h>
#include <net/tcp.h>
static DEFINE_SPINLOCK(tcp_ulp_list_lock);
static LIST_HEAD(tcp_ulp_list);
/* Simple linear search, don't expect many entries! */
static struct tcp_ulp_ops *tcp_ulp_find(const char *name)
{
struct tcp_ulp_ops *e;
list_for_each_entry_rcu(e, &tcp_ulp_list, list,
lockdep_is_held(&tcp_ulp_list_lock)) {
if (strcmp(e->name, name) == 0)
return e;
}
return NULL;
}
static const struct tcp_ulp_ops *__tcp_ulp_find_autoload(const char *name)
{
const struct tcp_ulp_ops *ulp = NULL;
rcu_read_lock();
ulp = tcp_ulp_find(name);
#ifdef CONFIG_MODULES
if (!ulp && capable(CAP_NET_ADMIN)) {
rcu_read_unlock();
request_module("tcp-ulp-%s", name);
rcu_read_lock();
ulp = tcp_ulp_find(name);
}
#endif
if (!ulp || !try_module_get(ulp->owner))
ulp = NULL;
rcu_read_unlock();
return ulp;
}
/* Attach new upper layer protocol to the list
* of available protocols.
*/
int tcp_register_ulp(struct tcp_ulp_ops *ulp)
{
int ret = 0;
spin_lock(&tcp_ulp_list_lock);
if (tcp_ulp_find(ulp->name))
ret = -EEXIST;
else
list_add_tail_rcu(&ulp->list, &tcp_ulp_list);
spin_unlock(&tcp_ulp_list_lock);
return ret;
}
EXPORT_SYMBOL_GPL(tcp_register_ulp);
void tcp_unregister_ulp(struct tcp_ulp_ops *ulp)
{
spin_lock(&tcp_ulp_list_lock);
list_del_rcu(&ulp->list);
spin_unlock(&tcp_ulp_list_lock);
synchronize_rcu();
}
EXPORT_SYMBOL_GPL(tcp_unregister_ulp);
/* Build string with list of available upper layer protocl values */
void tcp_get_available_ulp(char *buf, size_t maxlen)
{
struct tcp_ulp_ops *ulp_ops;
size_t offs = 0;
*buf = '\0';
rcu_read_lock();
list_for_each_entry_rcu(ulp_ops, &tcp_ulp_list, list) {
offs += snprintf(buf + offs, maxlen - offs,
"%s%s",
offs == 0 ? "" : " ", ulp_ops->name);
if (WARN_ON_ONCE(offs >= maxlen))
break;
}
rcu_read_unlock();
}
void tcp_update_ulp(struct sock *sk, struct proto *proto,
void (*write_space)(struct sock *sk))
{
struct inet_connection_sock *icsk = inet_csk(sk);
if (!icsk->icsk_ulp_ops) {
sk->sk_write_space = write_space;
/* Pairs with lockless read in sk_clone_lock() */
WRITE_ONCE(sk->sk_prot, proto);
return;
}
if (icsk->icsk_ulp_ops->update)
icsk->icsk_ulp_ops->update(sk, proto, write_space);
}
void tcp_cleanup_ulp(struct sock *sk)
{
struct inet_connection_sock *icsk = inet_csk(sk);
/* No sock_owned_by_me() check here as at the time the
* stack calls this function, the socket is dead and
* about to be destroyed.
*/
if (!icsk->icsk_ulp_ops)
return;
if (icsk->icsk_ulp_ops->release)
icsk->icsk_ulp_ops->release(sk);
module_put(icsk->icsk_ulp_ops->owner);
icsk->icsk_ulp_ops = NULL;
}
static int __tcp_set_ulp(struct sock *sk, const struct tcp_ulp_ops *ulp_ops)
{
struct inet_connection_sock *icsk = inet_csk(sk);
int err;
err = -EEXIST;
if (icsk->icsk_ulp_ops)
goto out_err;
err = ulp_ops->init(sk);
if (err)
goto out_err;
icsk->icsk_ulp_ops = ulp_ops;
return 0;
out_err:
module_put(ulp_ops->owner);
return err;
}
int tcp_set_ulp(struct sock *sk, const char *name)
{
const struct tcp_ulp_ops *ulp_ops;
sock_owned_by_me(sk);
ulp_ops = __tcp_ulp_find_autoload(name);
if (!ulp_ops)
return -ENOENT;
return __tcp_set_ulp(sk, ulp_ops);
}
|
