drivers/infiniband/core/netlink.c - linux - Git at Google

 /*
  * Copyright (c) 2017 Mellanox Technologies Inc.  All rights reserved.
  * Copyright (c) 2010 Voltaire Inc.  All rights reserved.
  *
  * This software is available to you under a choice of one of two
  * licenses.  You may choose to be licensed under the terms of the GNU
  * General Public License (GPL) Version 2, available from the file
  * COPYING in the main directory of this source tree, or the
  * OpenIB.org BSD license below:
  *
  *     Redistribution and use in source and binary forms, with or
  *     without modification, are permitted provided that the following
  *     conditions are met:
  *
  *      - Redistributions of source code must retain the above
  *        copyright notice, this list of conditions and the following
  *        disclaimer.
  *
  *      - Redistributions in binary form must reproduce the above
  *        copyright notice, this list of conditions and the following
  *        disclaimer in the documentation and/or other materials
  *        provided with the distribution.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  */

 #define pr_fmt(fmt) "%s:%s: " fmt, KBUILD_MODNAME, __func__

 #include <linux/export.h>
 #include <net/netlink.h>
 #include <net/net_namespace.h>
 #include <net/netns/generic.h>
 #include <net/sock.h>
 #include <rdma/rdma_netlink.h>
 #include <linux/module.h>
 #include "core_priv.h"

 static struct {
 	const struct rdma_nl_cbs *cb_table;
 	/* Synchronizes between ongoing netlink commands and netlink client
 	 * unregistration.
 	 */
 	struct rw_semaphore sem;
 } rdma_nl_types[RDMA_NL_NUM_CLIENTS];

 bool rdma_nl_chk_listeners(unsigned int group)
 {
 	struct rdma_dev_net *rnet = rdma_net_to_dev_net(&init_net);

 	return netlink_has_listeners(rnet->nl_sock, group);
 }
 EXPORT_SYMBOL(rdma_nl_chk_listeners);

 static bool is_nl_msg_valid(unsigned int type, unsigned int op)
 {
 	static const unsigned int max_num_ops[RDMA_NL_NUM_CLIENTS] = {
 		[RDMA_NL_IWCM] = RDMA_NL_IWPM_NUM_OPS,
 		[RDMA_NL_LS] = RDMA_NL_LS_NUM_OPS,
 		[RDMA_NL_NLDEV] = RDMA_NLDEV_NUM_OPS,
 	};

 	/*
 	 * This BUILD_BUG_ON is intended to catch addition of new
 	 * RDMA netlink protocol without updating the array above.
 	 */
 	BUILD_BUG_ON(RDMA_NL_NUM_CLIENTS != 6);

 	if (type >= RDMA_NL_NUM_CLIENTS)
 		return false;

 	return (op < max_num_ops[type]) ? true : false;
 }

 static const struct rdma_nl_cbs *
 get_cb_table(const struct sk_buff *skb, unsigned int type, unsigned int op)
 {
 	const struct rdma_nl_cbs *cb_table;

 	/*
 	 * Currently only NLDEV client is supporting netlink commands in
 	 * non init_net net namespace.
 	 */
 	if (sock_net(skb->sk) != &init_net && type != RDMA_NL_NLDEV)
 		return NULL;

 	cb_table = READ_ONCE(rdma_nl_types[type].cb_table);
 	if (!cb_table) {
 		/*
 		 * Didn't get valid reference of the table, attempt module
 		 * load once.
 		 */
 		up_read(&rdma_nl_types[type].sem);

 		request_module("rdma-netlink-subsys-%d", type);

 		down_read(&rdma_nl_types[type].sem);
 		cb_table = READ_ONCE(rdma_nl_types[type].cb_table);
 	}
 	if (!cb_table || (!cb_table[op].dump && !cb_table[op].doit))
 		return NULL;
 	return cb_table;
 }

 void rdma_nl_register(unsigned int index,
 		      const struct rdma_nl_cbs cb_table[])
 {
 	if (WARN_ON(!is_nl_msg_valid(index, 0)) ||
 	    WARN_ON(READ_ONCE(rdma_nl_types[index].cb_table)))
 		return;

 	/* Pairs with the READ_ONCE in is_nl_valid() */
 	smp_store_release(&rdma_nl_types[index].cb_table, cb_table);
 }
 EXPORT_SYMBOL(rdma_nl_register);

 void rdma_nl_unregister(unsigned int index)
 {
 	down_write(&rdma_nl_types[index].sem);
 	rdma_nl_types[index].cb_table = NULL;
 	up_write(&rdma_nl_types[index].sem);
 }
 EXPORT_SYMBOL(rdma_nl_unregister);

 void *ibnl_put_msg(struct sk_buff *skb, struct nlmsghdr **nlh, int seq,
 		   int len, int client, int op, int flags)
 {
 	*nlh = nlmsg_put(skb, 0, seq, RDMA_NL_GET_TYPE(client, op), len, flags);
 	if (!*nlh)
 		return NULL;
 	return nlmsg_data(*nlh);
 }
 EXPORT_SYMBOL(ibnl_put_msg);

 int ibnl_put_attr(struct sk_buff *skb, struct nlmsghdr *nlh,
 		  int len, void *data, int type)
 {
 	if (nla_put(skb, type, len, data)) {
 		nlmsg_cancel(skb, nlh);
 		return -EMSGSIZE;
 	}
 	return 0;
 }
 EXPORT_SYMBOL(ibnl_put_attr);

 static int rdma_nl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
 			   struct netlink_ext_ack *extack)
 {
 	int type = nlh->nlmsg_type;
 	unsigned int index = RDMA_NL_GET_CLIENT(type);
 	unsigned int op = RDMA_NL_GET_OP(type);
 	const struct rdma_nl_cbs *cb_table;
 	int err = -EINVAL;

 	if (!is_nl_msg_valid(index, op))
 		return -EINVAL;

 	down_read(&rdma_nl_types[index].sem);
 	cb_table = get_cb_table(skb, index, op);
 	if (!cb_table)
 		goto done;

 	if ((cb_table[op].flags & RDMA_NL_ADMIN_PERM) &&
 	    !netlink_capable(skb, CAP_NET_ADMIN)) {
 		err = -EPERM;
 		goto done;
 	}

 	/*
 	 * LS responses overload the 0x100 (NLM_F_ROOT) flag.  Don't
 	 * mistakenly call the .dump() function.
 	 */
 	if (index == RDMA_NL_LS) {
 		if (cb_table[op].doit)
 			err = cb_table[op].doit(skb, nlh, extack);
 		goto done;
 	}
 	/* FIXME: Convert IWCM to properly handle doit callbacks */
 	if ((nlh->nlmsg_flags & NLM_F_DUMP) || index == RDMA_NL_IWCM) {
 		struct netlink_dump_control c = {
 			.dump = cb_table[op].dump,
 		};
 		if (c.dump)
 			err = netlink_dump_start(skb->sk, skb, nlh, &c);
 		goto done;
 	}

 	if (cb_table[op].doit)
 		err = cb_table[op].doit(skb, nlh, extack);
 done:
 	up_read(&rdma_nl_types[index].sem);
 	return err;
 }

 /*
  * This function is similar to netlink_rcv_skb with one exception:
  * It calls to the callback for the netlink messages without NLM_F_REQUEST
  * flag. These messages are intended for RDMA_NL_LS consumer, so it is allowed
  * for that consumer only.
  */
 static int rdma_nl_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
 						   struct nlmsghdr *,
 						   struct netlink_ext_ack *))
 {
 	struct netlink_ext_ack extack = {};
 	struct nlmsghdr *nlh;
 	int err;

 	while (skb->len >= nlmsg_total_size(0)) {
 		int msglen;

 		nlh = nlmsg_hdr(skb);
 		err = 0;

 		if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
 			return 0;

 		/*
 		 * Generally speaking, the only requests are handled
 		 * by the kernel, but RDMA_NL_LS is different, because it
 		 * runs backward netlink scheme. Kernel initiates messages
 		 * and waits for reply with data to keep pathrecord cache
 		 * in sync.
 		 */
 		if (!(nlh->nlmsg_flags & NLM_F_REQUEST) &&
 		    (RDMA_NL_GET_CLIENT(nlh->nlmsg_type) != RDMA_NL_LS))
 			goto ack;

 		/* Skip control messages */
 		if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
 			goto ack;

 		err = cb(skb, nlh, &extack);
 		if (err == -EINTR)
 			goto skip;

 ack:
 		if (nlh->nlmsg_flags & NLM_F_ACK || err)
 			netlink_ack(skb, nlh, err, &extack);

 skip:
 		msglen = NLMSG_ALIGN(nlh->nlmsg_len);
 		if (msglen > skb->len)
 			msglen = skb->len;
 		skb_pull(skb, msglen);
 	}

 	return 0;
 }

 static void rdma_nl_rcv(struct sk_buff *skb)
 {
 	rdma_nl_rcv_skb(skb, &rdma_nl_rcv_msg);
 }

 int rdma_nl_unicast(struct net *net, struct sk_buff *skb, u32 pid)
 {
 	struct rdma_dev_net *rnet = rdma_net_to_dev_net(net);
 	int err;

 	err = netlink_unicast(rnet->nl_sock, skb, pid, MSG_DONTWAIT);
 	return (err < 0) ? err : 0;
 }
 EXPORT_SYMBOL(rdma_nl_unicast);

 int rdma_nl_unicast_wait(struct net *net, struct sk_buff *skb, __u32 pid)
 {
 	struct rdma_dev_net *rnet = rdma_net_to_dev_net(net);
 	int err;

 	err = netlink_unicast(rnet->nl_sock, skb, pid, 0);
 	return (err < 0) ? err : 0;
 }
 EXPORT_SYMBOL(rdma_nl_unicast_wait);

 int rdma_nl_multicast(struct net *net, struct sk_buff *skb,
 		      unsigned int group, gfp_t flags)
 {
 	struct rdma_dev_net *rnet = rdma_net_to_dev_net(net);

 	return nlmsg_multicast(rnet->nl_sock, skb, 0, group, flags);
 }
 EXPORT_SYMBOL(rdma_nl_multicast);

 void rdma_nl_init(void)
 {
 	int idx;

 	for (idx = 0; idx < RDMA_NL_NUM_CLIENTS; idx++)
 		init_rwsem(&rdma_nl_types[idx].sem);
 }

 void rdma_nl_exit(void)
 {
 	int idx;

 	for (idx = 0; idx < RDMA_NL_NUM_CLIENTS; idx++)
 		WARN(rdma_nl_types[idx].cb_table,
 		     "Netlink client %d wasn't released prior to unloading %s\n",
 		     idx, KBUILD_MODNAME);
 }

 int rdma_nl_net_init(struct rdma_dev_net *rnet)
 {
 	struct net *net = read_pnet(&rnet->net);
 	struct netlink_kernel_cfg cfg = {
 		.input	= rdma_nl_rcv,
 	};
 	struct sock *nls;

 	nls = netlink_kernel_create(net, NETLINK_RDMA, &cfg);
 	if (!nls)
 		return -ENOMEM;

 	nls->sk_sndtimeo = 10 * HZ;
 	rnet->nl_sock = nls;
 	return 0;
 }

 void rdma_nl_net_exit(struct rdma_dev_net *rnet)
 {
 	netlink_kernel_release(rnet->nl_sock);
 }

 MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_RDMA);
	/*
	* Copyright (c) 2017 Mellanox Technologies Inc. All rights reserved.
	* Copyright (c) 2010 Voltaire Inc. All rights reserved.
	*
	* This software is available to you under a choice of one of two
	* licenses. You may choose to be licensed under the terms of the GNU
	* General Public License (GPL) Version 2, available from the file
	* COPYING in the main directory of this source tree, or the
	* OpenIB.org BSD license below:
	*
	* Redistribution and use in source and binary forms, with or
	* without modification, are permitted provided that the following
	* conditions are met:
	*
	* - Redistributions of source code must retain the above
	* copyright notice, this list of conditions and the following
	* disclaimer.
	*
	* - Redistributions in binary form must reproduce the above
	* copyright notice, this list of conditions and the following
	* disclaimer in the documentation and/or other materials
	* provided with the distribution.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
	* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
	* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
	* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
	* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
	* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
	* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
	* SOFTWARE.
	*/

	#define pr_fmt(fmt) "%s:%s: " fmt, KBUILD_MODNAME, __func__

	#include <linux/export.h>
	#include <net/netlink.h>
	#include <net/net_namespace.h>
	#include <net/netns/generic.h>
	#include <net/sock.h>
	#include <rdma/rdma_netlink.h>
	#include <linux/module.h>
	#include "core_priv.h"

	static struct {
	const struct rdma_nl_cbs *cb_table;
	/* Synchronizes between ongoing netlink commands and netlink client
	* unregistration.
	*/
	struct rw_semaphore sem;
	} rdma_nl_types[RDMA_NL_NUM_CLIENTS];

	bool rdma_nl_chk_listeners(unsigned int group)
	{
	struct rdma_dev_net *rnet = rdma_net_to_dev_net(&init_net);

	return netlink_has_listeners(rnet->nl_sock, group);
	}
	EXPORT_SYMBOL(rdma_nl_chk_listeners);

	static bool is_nl_msg_valid(unsigned int type, unsigned int op)
	{
	static const unsigned int max_num_ops[RDMA_NL_NUM_CLIENTS] = {
	[RDMA_NL_IWCM] = RDMA_NL_IWPM_NUM_OPS,
	[RDMA_NL_LS] = RDMA_NL_LS_NUM_OPS,
	[RDMA_NL_NLDEV] = RDMA_NLDEV_NUM_OPS,
	};

	/*
	* This BUILD_BUG_ON is intended to catch addition of new
	* RDMA netlink protocol without updating the array above.
	*/
	BUILD_BUG_ON(RDMA_NL_NUM_CLIENTS != 6);

	if (type >= RDMA_NL_NUM_CLIENTS)
	return false;

	return (op < max_num_ops[type]) ? true : false;
	}

	static const struct rdma_nl_cbs *
	get_cb_table(const struct sk_buff *skb, unsigned int type, unsigned int op)
	{
	const struct rdma_nl_cbs *cb_table;

	/*
	* Currently only NLDEV client is supporting netlink commands in
	* non init_net net namespace.
	*/
	if (sock_net(skb->sk) != &init_net && type != RDMA_NL_NLDEV)
	return NULL;

	cb_table = READ_ONCE(rdma_nl_types[type].cb_table);
	if (!cb_table) {
	/*
	* Didn't get valid reference of the table, attempt module
	* load once.
	*/
	up_read(&rdma_nl_types[type].sem);

	request_module("rdma-netlink-subsys-%d", type);

	down_read(&rdma_nl_types[type].sem);
	cb_table = READ_ONCE(rdma_nl_types[type].cb_table);
	}
	if (!cb_table \|\| (!cb_table[op].dump && !cb_table[op].doit))
	return NULL;
	return cb_table;
	}

	void rdma_nl_register(unsigned int index,
	const struct rdma_nl_cbs cb_table[])
	{
	if (WARN_ON(!is_nl_msg_valid(index, 0)) \|\|
	WARN_ON(READ_ONCE(rdma_nl_types[index].cb_table)))
	return;

	/* Pairs with the READ_ONCE in is_nl_valid() */
	smp_store_release(&rdma_nl_types[index].cb_table, cb_table);
	}
	EXPORT_SYMBOL(rdma_nl_register);

	void rdma_nl_unregister(unsigned int index)
	{
	down_write(&rdma_nl_types[index].sem);
	rdma_nl_types[index].cb_table = NULL;
	up_write(&rdma_nl_types[index].sem);
	}
	EXPORT_SYMBOL(rdma_nl_unregister);

	void ibnl_put_msg(struct sk_buff skb, struct nlmsghdr **nlh, int seq,
	int len, int client, int op, int flags)
	{
	*nlh = nlmsg_put(skb, 0, seq, RDMA_NL_GET_TYPE(client, op), len, flags);
	if (!*nlh)
	return NULL;
	return nlmsg_data(*nlh);
	}
	EXPORT_SYMBOL(ibnl_put_msg);

	int ibnl_put_attr(struct sk_buff skb, struct nlmsghdr nlh,
	int len, void *data, int type)
	{
	if (nla_put(skb, type, len, data)) {
	nlmsg_cancel(skb, nlh);
	return -EMSGSIZE;
	}
	return 0;
	}
	EXPORT_SYMBOL(ibnl_put_attr);

	static int rdma_nl_rcv_msg(struct sk_buff skb, struct nlmsghdr nlh,
	struct netlink_ext_ack *extack)
	{
	int type = nlh->nlmsg_type;
	unsigned int index = RDMA_NL_GET_CLIENT(type);
	unsigned int op = RDMA_NL_GET_OP(type);
	const struct rdma_nl_cbs *cb_table;
	int err = -EINVAL;

	if (!is_nl_msg_valid(index, op))
	return -EINVAL;

	down_read(&rdma_nl_types[index].sem);
	cb_table = get_cb_table(skb, index, op);
	if (!cb_table)
	goto done;

	if ((cb_table[op].flags & RDMA_NL_ADMIN_PERM) &&
	!netlink_capable(skb, CAP_NET_ADMIN)) {
	err = -EPERM;
	goto done;
	}

	/*
	* LS responses overload the 0x100 (NLM_F_ROOT) flag. Don't
	* mistakenly call the .dump() function.
	*/
	if (index == RDMA_NL_LS) {
	if (cb_table[op].doit)
	err = cb_table[op].doit(skb, nlh, extack);
	goto done;
	}
	/* FIXME: Convert IWCM to properly handle doit callbacks */
	if ((nlh->nlmsg_flags & NLM_F_DUMP) \|\| index == RDMA_NL_IWCM) {
	struct netlink_dump_control c = {
	.dump = cb_table[op].dump,
	};
	if (c.dump)
	err = netlink_dump_start(skb->sk, skb, nlh, &c);
	goto done;
	}

	if (cb_table[op].doit)
	err = cb_table[op].doit(skb, nlh, extack);
	done:
	up_read(&rdma_nl_types[index].sem);
	return err;
	}

	/*
	* This function is similar to netlink_rcv_skb with one exception:
	* It calls to the callback for the netlink messages without NLM_F_REQUEST
	* flag. These messages are intended for RDMA_NL_LS consumer, so it is allowed
	* for that consumer only.
	*/
	static int rdma_nl_rcv_skb(struct sk_buff skb, int (cb)(struct sk_buff *,
	struct nlmsghdr *,
	struct netlink_ext_ack *))
	{
	struct netlink_ext_ack extack = {};
	struct nlmsghdr *nlh;
	int err;

	while (skb->len >= nlmsg_total_size(0)) {
	int msglen;

	nlh = nlmsg_hdr(skb);
	err = 0;

	if (nlh->nlmsg_len < NLMSG_HDRLEN \|\| skb->len < nlh->nlmsg_len)
	return 0;

	/*
	* Generally speaking, the only requests are handled
	* by the kernel, but RDMA_NL_LS is different, because it
	* runs backward netlink scheme. Kernel initiates messages
	* and waits for reply with data to keep pathrecord cache
	* in sync.
	*/
	if (!(nlh->nlmsg_flags & NLM_F_REQUEST) &&
	(RDMA_NL_GET_CLIENT(nlh->nlmsg_type) != RDMA_NL_LS))
	goto ack;

	/* Skip control messages */
	if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
	goto ack;

	err = cb(skb, nlh, &extack);
	if (err == -EINTR)
	goto skip;

	ack:
	if (nlh->nlmsg_flags & NLM_F_ACK \|\| err)
	netlink_ack(skb, nlh, err, &extack);

	skip:
	msglen = NLMSG_ALIGN(nlh->nlmsg_len);
	if (msglen > skb->len)
	msglen = skb->len;
	skb_pull(skb, msglen);
	}

	return 0;
	}

	static void rdma_nl_rcv(struct sk_buff *skb)
	{
	rdma_nl_rcv_skb(skb, &rdma_nl_rcv_msg);
	}

	int rdma_nl_unicast(struct net net, struct sk_buff skb, u32 pid)
	{
	struct rdma_dev_net *rnet = rdma_net_to_dev_net(net);
	int err;

	err = netlink_unicast(rnet->nl_sock, skb, pid, MSG_DONTWAIT);
	return (err < 0) ? err : 0;
	}
	EXPORT_SYMBOL(rdma_nl_unicast);

	int rdma_nl_unicast_wait(struct net net, struct sk_buff skb, __u32 pid)
	{
	struct rdma_dev_net *rnet = rdma_net_to_dev_net(net);
	int err;

	err = netlink_unicast(rnet->nl_sock, skb, pid, 0);
	return (err < 0) ? err : 0;
	}
	EXPORT_SYMBOL(rdma_nl_unicast_wait);

	int rdma_nl_multicast(struct net net, struct sk_buff skb,
	unsigned int group, gfp_t flags)
	{
	struct rdma_dev_net *rnet = rdma_net_to_dev_net(net);

	return nlmsg_multicast(rnet->nl_sock, skb, 0, group, flags);
	}
	EXPORT_SYMBOL(rdma_nl_multicast);

	void rdma_nl_init(void)
	{
	int idx;

	for (idx = 0; idx < RDMA_NL_NUM_CLIENTS; idx++)
	init_rwsem(&rdma_nl_types[idx].sem);
	}

	void rdma_nl_exit(void)
	{
	int idx;

	for (idx = 0; idx < RDMA_NL_NUM_CLIENTS; idx++)
	WARN(rdma_nl_types[idx].cb_table,
	"Netlink client %d wasn't released prior to unloading %s\n",
	idx, KBUILD_MODNAME);
	}

	int rdma_nl_net_init(struct rdma_dev_net *rnet)
	{
	struct net *net = read_pnet(&rnet->net);
	struct netlink_kernel_cfg cfg = {
	.input = rdma_nl_rcv,
	};
	struct sock *nls;

	nls = netlink_kernel_create(net, NETLINK_RDMA, &cfg);
	if (!nls)
	return -ENOMEM;

	nls->sk_sndtimeo = 10 * HZ;
	rnet->nl_sock = nls;
	return 0;
	}

	void rdma_nl_net_exit(struct rdma_dev_net *rnet)
	{
	netlink_kernel_release(rnet->nl_sock);
	}

	MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_RDMA);