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/*
* Copyright (c) 2007-2012 Nicira, Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*
* This program 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/version.h>
#include <linux/completion.h>
#include <net/genetlink.h>
#include "genl_exec.h"
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,35)
static DEFINE_MUTEX(genl_exec_lock);
static genl_exec_func_t genl_exec_function;
static int genl_exec_function_ret;
static void *genl_exec_data;
static struct completion done;
static struct sk_buff *genlmsg_skb;
static int genl_exec_cmd(struct sk_buff *dummy, struct genl_info *dummy2)
{
genl_exec_function_ret = genl_exec_function(genl_exec_data);
complete(&done);
return 0;
}
enum exec_cmd {
GENL_EXEC_UNSPEC,
GENL_EXEC_RUN,
};
static struct genl_family genl_exec_family = {
.id = GENL_ID_GENERATE,
.name = "ovs_genl_exec",
.version = 1,
};
static struct genl_ops genl_exec_ops[] = {
{
.cmd = GENL_EXEC_RUN,
.doit = genl_exec_cmd,
.flags = CAP_NET_ADMIN,
},
};
int genl_exec_init(void)
{
int err;
err = genl_register_family_with_ops(&genl_exec_family,
genl_exec_ops, ARRAY_SIZE(genl_exec_ops));
if (err)
return err;
genlmsg_skb = genlmsg_new(0, GFP_KERNEL);
if (!genlmsg_skb) {
genl_unregister_family(&genl_exec_family);
return -ENOMEM;
}
return 0;
}
void genl_exec_exit(void)
{
kfree_skb(genlmsg_skb);
genl_unregister_family(&genl_exec_family);
}
/* genl_lock() is not exported from older kernel.
* Following function allows any function to be executed with
* genl_mutex held. */
int genl_exec(genl_exec_func_t func, void *data)
{
int ret;
mutex_lock(&genl_exec_lock);
init_completion(&done);
skb_get(genlmsg_skb);
genlmsg_put(genlmsg_skb, 0, 0, &genl_exec_family,
NLM_F_REQUEST, GENL_EXEC_RUN);
genl_exec_function = func;
genl_exec_data = data;
/* There is no need to send msg to current namespace. */
ret = genlmsg_unicast(&init_net, genlmsg_skb, 0);
if (!ret) {
wait_for_completion(&done);
ret = genl_exec_function_ret;
} else {
pr_err("genl_exec send error %d\n", ret);
}
/* Wait for genetlink to kfree skb. */
while (skb_shared(genlmsg_skb))
cpu_relax();
genlmsg_skb->data = genlmsg_skb->head;
skb_reset_tail_pointer(genlmsg_skb);
mutex_unlock(&genl_exec_lock);
return ret;
}
#else
int genl_exec(genl_exec_func_t func, void *data)
{
int ret;
genl_lock();
ret = func(data);
genl_unlock();
return ret;
}
int genl_exec_init(void)
{
return 0;
}
void genl_exec_exit(void)
{
}
#endif
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