Differential D36002 Diff 110147 sys/netlink/netlink_module.c

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sys/netlink/netlink_module.c

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				/*-
				* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
				*
				* Copyright (c) 2021 Ng Peng Nam Sean
				Lint: Possible Spelling Mistake Inline Actions Possible spelling error. You wrote 'nam', but did you mean 'name'? Lint: Possible Spelling Mistake: Possible spelling error. You wrote 'nam', but did you mean 'name'?
				* Copyright (c) 2022 Alexander V. Chernikov
				*
				* Redistribution and use in source and binary forms, with or without
				* modification, are permitted provided that the following conditions
				* are met:
				* 1. Redistributions of source code must retain the above copyright
				* notice, this list of conditions and the following disclaimer.
				* 2. 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.
				*
				* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
				* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
				* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
				* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
				* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
				* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
				* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
				* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
				* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
				* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
				* SUCH DAMAGE.
				*/

				#include <sys/cdefs.h>
				__FBSDID("$FreeBSD$");
				#include <sys/param.h>
				#include <sys/malloc.h>
				#include <sys/module.h>

				#include <sys/lock.h>
				#include <sys/rmlock.h>
				#include <sys/ck.h>
				#include <sys/syslog.h>

				#include <netlink/netlink.h>
				#include <netlink/netlink_ctl.h>
				#include <netlink/netlink_var.h>

				#include <machine/atomic.h>

				MALLOC_DEFINE(M_NETLINK, "netlink", "Memory used for netlink packets");

				#define DEBUG_MOD_NAME nl_mod
				#define DEBUG_MAX_LEVEL LOG_DEBUG3
				#include <netlink/netlink_debug.h>
				_DECLARE_DEBUG(LOG_DEBUG);

				SYSCTL_NODE(_net, OID_AUTO, netlink, CTLFLAG_RD, 0, "");
				SYSCTL_NODE(_net_netlink, OID_AUTO, debug, CTLFLAG_RD \| CTLFLAG_MPSAFE, 0, "");

				#define NL_MAX_HANDLERS 20
				struct nl_proto_handler _nl_handlers[NL_MAX_HANDLERS];
				struct nl_proto_handler *nl_handlers = _nl_handlers;

				CK_LIST_HEAD(nl_control_head, nl_control);
				static struct nl_control_head vnets_head = CK_LIST_HEAD_INITIALIZER();

				VNET_DEFINE(struct nl_control *, nl_ctl) = NULL;

				struct mtx nl_global_mtx;
				MTX_SYSINIT(nl_global_mtx, &nl_global_mtx, "global netlink lock", MTX_DEF);

				#define NL_GLOBAL_LOCK() mtx_lock(&nl_global_mtx)
				#define NL_GLOBAL_UNLOCK() mtx_unlock(&nl_global_mtx)

				int netlink_unloading = 0;

				static void
				free_nl_ctl(struct nl_control *ctl)
				{
				rm_destroy(&ctl->ctl_lock);
				free(ctl, M_NETLINK);
				}

				struct nl_control *
				vnet_nl_ctl_init(void)
				{
				struct nl_control *ctl;

				ctl = malloc(sizeof(struct nl_control), M_NETLINK, M_WAITOK \| M_ZERO);
				rm_init(&ctl->ctl_lock, "netlink lock");
				CK_LIST_INIT(&ctl->ctl_port_head);
				CK_LIST_INIT(&ctl->ctl_pcb_head);

				NL_GLOBAL_LOCK();

				struct nl_control *tmp = atomic_load_ptr(&V_nl_ctl);

				if (tmp == NULL) {
				atomic_store_ptr(&V_nl_ctl, ctl);
				CK_LIST_INSERT_HEAD(&vnets_head, ctl, ctl_next);
				NL_LOG(LOG_DEBUG2, "VNET %p init done, inserted %p into global list",
				curvnet, ctl);
				} else {
				NL_LOG(LOG_DEBUG, "per-VNET init clash, dropping this instance");
				free_nl_ctl(ctl);
				ctl = tmp;
				}

				NL_GLOBAL_UNLOCK();

				return (ctl);
				}

				static void
				vnet_nl_ctl_destroy(const void *unused __unused)
				{
				struct nl_control *ctl;

				/* Assume at the time all of the processes / sockets are dead */

				NL_GLOBAL_LOCK();
				ctl = atomic_load_ptr(&V_nl_ctl);
				atomic_store_ptr(&V_nl_ctl, NULL);
				if (ctl != NULL) {
				NL_LOG(LOG_DEBUG2, "Removing %p from global list", ctl);
				CK_LIST_REMOVE(ctl, ctl_next);
				}
				NL_GLOBAL_UNLOCK();

				if (ctl != NULL)
				free_nl_ctl(ctl);
				}
				VNET_SYSUNINIT(vnet_nl_ctl_destroy, SI_SUB_PROTO_IF, SI_ORDER_ANY,
				vnet_nl_ctl_destroy, NULL);

				int
				nl_verify_proto(int proto)
				{
				if (proto < 0 \|\| proto >= NL_MAX_HANDLERS) {
				return (EINVAL);
				}
				int handler_defined = nl_handlers[proto].cb != NULL;
				return (handler_defined ? 0 : EPROTONOSUPPORT);
				}

				const char *
				nl_get_proto_name(int proto)
				{
				return (nl_handlers[proto].proto_name);
				}

				bool
				netlink_register_proto(int proto, const char *proto_name, nl_handler_f handler)
				{
				if ((proto < 0) \|\| (proto >= NL_MAX_HANDLERS))
				return (false);
				NL_GLOBAL_LOCK();
				KASSERT((nl_handlers[proto].cb == NULL), ("netlink handler %d is already set", proto));
				nl_handlers[proto].cb = handler;
				nl_handlers[proto].proto_name = proto_name;
				NL_GLOBAL_UNLOCK();
				NL_LOG(LOG_DEBUG, "Registered netlink %s(%d) handler", proto_name, proto);
				return (true);
				}

				bool
				netlink_unregister_proto(int proto)
				{
				if ((proto < 0) \|\| (proto >= NL_MAX_HANDLERS))
				return (false);
				NL_GLOBAL_LOCK();
				KASSERT((nl_handlers[proto].cb != NULL), ("netlink handler %d is not set", proto));
				nl_handlers[proto].cb = NULL;
				nl_handlers[proto].proto_name = NULL;
				NL_GLOBAL_UNLOCK();
				NL_LOG(LOG_DEBUG, "Unregistered netlink proto %d handler", proto);
				return (true);
				}

				static bool
				can_unload(void)
				{
				struct nl_control *ctl;
				bool result = true;

				NL_GLOBAL_LOCK();

				CK_LIST_FOREACH(ctl, &vnets_head, ctl_next) {
				NL_LOG(LOG_DEBUG2, "Iterating VNET head %p", ctl);
				if (!CK_LIST_EMPTY(&ctl->ctl_pcb_head)) {
				NL_LOG(LOG_NOTICE, "non-empty socket list in ctl %p", ctl);
				result = false;
				break;
				}
				}

				NL_GLOBAL_UNLOCK();

				return (result);
				}

				static int
				netlink_modevent(module_t mod __unused, int what, void *priv __unused)
				{
				int ret = 0;

				switch (what) {
				case MOD_LOAD:
				NL_LOG(LOG_DEBUG, "Loading");
				NL_LOG(LOG_NOTICE, "netlink support is in BETA stage");
				break;

				case MOD_UNLOAD:
				NL_LOG(LOG_DEBUG, "Unload called");
				if (can_unload()) {
				NL_LOG(LOG_WARNING, "unloading");
				netlink_unloading = 1;
				} else
				ret = EBUSY;
				break;

				default:
				ret = EOPNOTSUPP;
				break;
				}

				return (ret);
				}
				static moduledata_t netlink_mod = { "netlink", netlink_modevent, NULL };

				DECLARE_MODULE(netlink, netlink_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
				MODULE_VERSION(netlink, 1);