FreeBSD/Linux Kernel Cross Reference
sys/netlink/netlink_route.c

     /*-
      * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
      *
      * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
      *
      * 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/types.h>
    #include <sys/ck.h>
    #include <sys/epoch.h>
    #include <sys/kernel.h>
    #include <sys/malloc.h>
    #include <sys/socket.h>
    
    #include <net/route.h>
    #include <net/route/route_ctl.h>
    #include <netlink/netlink.h>
    #include <netlink/netlink_ctl.h>
    #include <netlink/netlink_route.h>
    #include <netlink/route/route_var.h>
    
    #define DEBUG_MOD_NAME  nl_route_core
    #define DEBUG_MAX_LEVEL LOG_DEBUG3
    #include <netlink/netlink_debug.h>
    _DECLARE_DEBUG(LOG_DEBUG);
    
    #define HANDLER_MAX_NUM (NL_RTM_MAX + 10)
    static const struct rtnl_cmd_handler *rtnl_handler[HANDLER_MAX_NUM] = {};
    
    bool
    rtnl_register_messages(const struct rtnl_cmd_handler *handlers, int count)
    {
            for (int i = 0; i < count; i++) {
                    if (handlers[i].cmd >= HANDLER_MAX_NUM)
                            return (false);
                    MPASS(rtnl_handler[handlers[i].cmd] == NULL);
            }
            for (int i = 0; i < count; i++)
                    rtnl_handler[handlers[i].cmd] = &handlers[i];
            return (true);
    }
    
    /*
     * Handler called by netlink subsystem when matching netlink message is received
     */
    static int
    rtnl_handle_message(struct nlmsghdr *hdr, struct nl_pstate *npt)
    {
            const struct rtnl_cmd_handler *cmd;
            struct epoch_tracker et;
            struct nlpcb *nlp = npt->nlp;
            int error = 0;
    
            if (__predict_false(hdr->nlmsg_type >= HANDLER_MAX_NUM)) {
                    NLMSG_REPORT_ERR_MSG(npt, "unknown message type: %d", hdr->nlmsg_type);
                    return (ENOTSUP);
            }
    
            cmd = rtnl_handler[hdr->nlmsg_type];
            if (__predict_false(cmd == NULL)) {
                    NLMSG_REPORT_ERR_MSG(npt, "unknown message type: %d", hdr->nlmsg_type);
                    return (ENOTSUP);
            }
    
            NLP_LOG(LOG_DEBUG2, nlp, "received msg %s(%d) len %d", cmd->name,
                hdr->nlmsg_type, hdr->nlmsg_len);
    
            if (cmd->priv != 0 && !nlp_has_priv(nlp, cmd->priv)) {
                    NLP_LOG(LOG_DEBUG2, nlp, "priv %d check failed for msg %s", cmd->priv, cmd->name);
                    return (EPERM);
            } else if (cmd->priv != 0)
                    NLP_LOG(LOG_DEBUG3, nlp, "priv %d check passed for msg %s", cmd->priv, cmd->name);
    
            bool need_epoch = !(cmd->flags & RTNL_F_NOEPOCH);
    
            if (need_epoch)
                    NET_EPOCH_ENTER(et);
           error = cmd->cb(hdr, nlp, npt);
           if (need_epoch)
                   NET_EPOCH_EXIT(et);
   
           NLP_LOG(LOG_DEBUG3, nlp, "message %s -> error %d", cmd->name, error);
   
           return (error);
   }
   
   static struct rtbridge nlbridge = {
           .route_f = rtnl_handle_route_event,
           .ifmsg_f = rtnl_handle_ifnet_event,
   };
   static struct rtbridge *nlbridge_orig_p;
   
   static void
   rtnl_load(void *u __unused)
   {
           NL_LOG(LOG_NOTICE, "rtnl loading");
           nlbridge_orig_p = netlink_callback_p;
           netlink_callback_p = &nlbridge;
           rtnl_neighs_init();
           rtnl_ifaces_init();
           rtnl_nexthops_init();
           rtnl_routes_init();
           netlink_register_proto(NETLINK_ROUTE, "NETLINK_ROUTE", rtnl_handle_message);
   }
   SYSINIT(rtnl_load, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, rtnl_load, NULL);
   
   static void
   rtnl_unload(void *u __unused)
   {
           netlink_callback_p = nlbridge_orig_p;
           rtnl_ifaces_destroy();
           rtnl_neighs_destroy();
   
           /* Wait till all consumers read nlbridge data */
           NET_EPOCH_WAIT();
   }
   SYSUNINIT(rtnl_unload, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, rtnl_unload, NULL);

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