Differential D26449 Diff 77371 sys/net/route/mpath_ctl.c

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sys/net/route/mpath_ctl.c

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				/*-
				* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
				*
				* Copyright (c) 2020 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.
				*
				* $FreeBSD$
				*/

				#include "opt_inet.h"
				#include "opt_route.h"

				#include <sys/cdefs.h>
				#include <sys/param.h>
				#include <sys/systm.h>
				#include <sys/lock.h>
				#include <sys/rmlock.h>
				#include <sys/rwlock.h>
				#include <sys/malloc.h>
				#include <sys/mbuf.h>
				#include <sys/socket.h>
				#include <sys/sysctl.h>
				#include <sys/kernel.h>

				#include <net/if.h>
				#include <net/if_var.h>
				#include <net/if_dl.h>
				#include <net/route.h>
				#include <net/route/route_ctl.h>
				#include <net/route/route_var.h>
				#include <net/vnet.h>

				#include <netinet/in.h>
				#include <netinet/in_var.h>
				#include <netinet/in_fib.h>

				#include <net/route/nhop_utils.h>
				#include <net/route/nhop.h>
				#include <net/route/nhop_var.h>

				/*
				* This file contains the supporting functions for adding/deleting/updating
				* multipath routes to the routing table.
				*/

				SYSCTL_DECL(_net_route);

				/*
				* Tries to add @rnd_add nhop to the existing set of nhops (@nh_orig) for the
				* prefix specified by @rt.
				*
				* Return 0 ans consumes rt / rnd_add nhop references. @rc gets populated
				* with the operation result.
				* Otherwise errno is returned.
				*
				* caller responsibility is to unlock/free rt and
				* rt->rt_nhop.
				*/
				int
				add_route_mpath(struct rib_head rnh, struct rt_addrinfo info,
				struct rtentry rt, struct route_nhop_data rnd_add,
				struct route_nhop_data rnd_orig, struct rib_cmd_info rc)
				{
				RIB_RLOCK_TRACKER;
				struct route_nhop_data rnd_new;
				int error = 0;

				/*
				* It is possible that multiple rtsock speakers will try to update
				* the same route simultaneously. Reduce the chance of failing the
				* request by retrying the cycle multiple times.
				*/
				for (int i = 0; i < RIB_MAX_RETRIES; i++) {
				error = nhgrp_get_addition_group(rnh, rnd_orig, rnd_add,
				&rnd_new);
				if (error != 0) {
				if (error != EAGAIN)
				break;

				/*
				* Group creation failed, most probably because
				* @rnd_orig data got scheduled for deletion.
				* Refresh @rnd_orig data and retry.
				*/
				RIB_RLOCK(rnh);
				lookup_prefix(rnh, info, rnd_orig);
				RIB_RUNLOCK(rnh);
				continue;
				}

				error = change_route_conditional(rnh, rt, info, rnd_orig,
				&rnd_new, rc);
				if (error != EAGAIN)
				break;
				RTSTAT_INC(rts_add_retry);
				}

				return (error);
				}

				struct rt_match_info {
				struct rt_addrinfo *info;
				struct rtentry *rt;
				};

				static bool
				gw_filter_func(const struct nhop_object nh, void _data)
				{
				struct rt_match_info ri = (struct rt_match_info )_data;

				return (check_info_match_nhop(ri->info, ri->rt, nh) == 0);
				}

				/*
				* Tries to delete matching paths from @nhg.
				* Returns 0 on success and updates operation result in @rc.
				*/
				int
				del_route_mpath(struct rib_head rh, struct rt_addrinfo info,
				struct rtentry rt, struct nhgrp_object nhg,
				struct rib_cmd_info *rc)
				{
				struct route_nhop_data rnd;
				struct rt_match_info ri = { .info = info, .rt = rt };
				int error;

				RIB_WLOCK_ASSERT(rh);

				/*
				* Require gateway to delete multipath routes, to forbid
				* deleting all paths at once.
				* If the filter function is provided, skip gateway check to
				* allow rib_walk_del() delete routes for any criteria based
				* on provided callback.
				*/
				if ((info->rti_info[RTAX_GATEWAY] == NULL) && (info->rti_filter == NULL))
				return (ESRCH);

				error = nhgrp_get_filtered_group(rh, nhg, gw_filter_func, (void *)&ri,
				&rnd);
				if (error == 0)
				error = change_route_nhop(rh, rt, info, &rnd, rc);
				return (error);
				}