blob: d311405ad04a495aa0a3ae6cd84417f3d044d94d (
plain)
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
|
/* netlink.c - Generic NETLINK API functions
*
* Copyright (C) 2009-2013 Red Hat Inc.
*
* David Sommerseth <davids@redhat.com>
*
* This application is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; version 2.
*
* This application is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*/
#include <Python.h>
#include <pthread.h>
#include <unistd.h>
#include <fcntl.h>
#include <netlink/netlink.h>
#include <netlink/socket.h>
#include "etherinfo_struct.h"
pthread_mutex_t nlc_counter_mtx = PTHREAD_MUTEX_INITIALIZER;
static struct nl_sock *nlconnection = NULL;
static unsigned int nlconnection_users = 0; /* How many NETLINK users are active? */
/**
* Connects to the NETLINK interface. This will be called
* for each etherinfo object being generated, and it will
* keep a separate file descriptor open for each object
*
* @param ethi PyEtherInfo structure (basically the "self" object)
*
* @return Returns 1 on success, otherwise 0.
*/
int open_netlink(PyEtherInfo *ethi)
{
if( !ethi ) {
return 0;
}
/* Reuse already established NETLINK connection, if a connection exists */
if( nlconnection ) {
/* If this object has not used NETLINK earlier, tag it as a user */
if( !ethi->nlc_active ) {
pthread_mutex_lock(&nlc_counter_mtx);
nlconnection_users++;
pthread_mutex_unlock(&nlc_counter_mtx);
}
ethi->nlc_active = 1;
return 1;
}
/* No earlier connections exists, establish a new one */
nlconnection = nl_socket_alloc();
if( nlconnection != NULL ) {
nl_connect(nlconnection, NETLINK_ROUTE);
/* Force O_CLOEXEC flag on the NETLINK socket */
if( fcntl(nl_socket_get_fd(nlconnection), F_SETFD, FD_CLOEXEC) == -1 ) {
fprintf(stderr,
"**WARNING** Failed to set O_CLOEXEC on NETLINK socket: %s\n",
strerror(errno));
}
/* Tag this object as an active user */
pthread_mutex_lock(&nlc_counter_mtx);
nlconnection_users++;
pthread_mutex_unlock(&nlc_counter_mtx);
ethi->nlc_active = 1;
return 1;
} else {
return 0;
}
}
/**
* Return a reference to the global netlink connection
*
* @returns Returns a pointer to a NETLINK connection libnl functions can use
*/
struct nl_sock * get_nlc()
{
assert(nlconnection);
return nlconnection;
}
/**
* Closes the NETLINK connection. This should be called automatically whenever
* the corresponding etherinfo object is deleted.
*
* @param ethi PyEtherInfo structure (basically the "self" object)
*/
void close_netlink(PyEtherInfo *ethi)
{
if( !ethi || !nlconnection ) {
return;
}
/* Untag this object as a NETLINK user */
ethi->nlc_active = 0;
pthread_mutex_lock(&nlc_counter_mtx);
nlconnection_users--;
pthread_mutex_unlock(&nlc_counter_mtx);
/* Don't close the connection if there are more users */
if( nlconnection_users > 0) {
return;
}
/* Close NETLINK connection */
nl_close(nlconnection);
nl_socket_free(nlconnection);
nlconnection = NULL;
}
/*
Local variables:
c-basic-offset: 8
indent-tabs-mode: y
End:
*/
|
