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b8a6e03fac
When epoch(9) was introduced to network stack, it was basically dropped in place of existing locking, which was mutexes and rwlocks. For the sake of performance mutex covered areas were as small as possible, so became epoch covered areas. However, epoch doesn't introduce any contention, it just delays memory reclaim. So, there is no point to minimise epoch covered areas in sense of performance. Meanwhile entering/exiting epoch also has non-zero CPU usage, so doing this less often is a win. Not the least is also code maintainability. In the new paradigm we can assume that at any stage of processing a packet, we are inside network epoch. This makes coding both input and output path way easier. On output path we already enter epoch quite early - in the ip_output(), in the ip6_output(). This patch does the same for the input path. All ISR processing, network related callouts, other ways of packet injection to the network stack shall be performed in net_epoch. Any leaf function that walks network configuration now asserts epoch. Tricky part is configuration code paths - ioctls, sysctls. They also call into leaf functions, so some need to be changed. This patch would introduce more epoch recursions (see EPOCH_TRACE) than we had before. They will be cleaned up separately, as several of them aren't trivial. Note, that unlike a lock recursion the epoch recursion is safe and just wastes a bit of resources. Reviewed by: gallatin, hselasky, cy, adrian, kristof Differential Revision: https://reviews.freebsd.org/D19111
148 lines
5.0 KiB
C
148 lines
5.0 KiB
C
/*
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* ng_ip_input.c
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*/
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/*-
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* SPDX-License-Identifier: BSD-3-Clause AND BSD-2-Clause
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*
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* Copyright 2001 The Aerospace Corporation. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions, and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions, and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of The Aerospace Corporation may not be used to endorse or
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* promote products derived from this software.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AEROSPACE CORPORATION "AS IS" AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AEROSPACE CORPORATION BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* Copyright (c) 1996-1999 Whistle Communications, Inc.
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* All rights reserved.
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*
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* Subject to the following obligations and disclaimer of warranty, use and
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* redistribution of this software, in source or object code forms, with or
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* without modifications are expressly permitted by Whistle Communications;
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* provided, however, that:
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* 1. Any and all reproductions of the source or object code must include the
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* copyright notice above and the following disclaimer of warranties; and
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* 2. No rights are granted, in any manner or form, to use Whistle
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* Communications, Inc. trademarks, including the mark "WHISTLE
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* COMMUNICATIONS" on advertising, endorsements, or otherwise except as
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* such appears in the above copyright notice or in the software.
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*
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* THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
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* TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
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* REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
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* INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
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* WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
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* REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
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* SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
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* IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
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* RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
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* WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
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* PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
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* OF SUCH DAMAGE.
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*
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* Author: Brooks Davis <brooks@FreeBSD.org>
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* Derived from: ng_hole.c
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*
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* $FreeBSD$
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*/
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/*
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* This node simply takes IP packets and calls ip_input on them
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/malloc.h>
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#include <sys/mbuf.h>
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#include <sys/socket.h>
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#include <sys/proc.h>
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#include <net/if.h>
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#include <net/if_types.h>
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#include <net/if_var.h>
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#include <netinet/in.h>
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#include <netinet/in_var.h>
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#include <net/netisr.h>
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#include <netgraph/ng_message.h>
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#include <netgraph/netgraph.h>
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#include <netgraph/ng_ip_input.h>
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/* Netgraph methods */
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static ng_constructor_t ngipi_cons;
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static ng_rcvdata_t ngipi_rcvdata;
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static ng_disconnect_t ngipi_disconnect;
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static struct ng_type typestruct = {
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.version = NG_ABI_VERSION,
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.name = NG_IP_INPUT_NODE_TYPE,
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.constructor = ngipi_cons,
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.rcvdata = ngipi_rcvdata,
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.disconnect = ngipi_disconnect,
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};
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NETGRAPH_INIT(ip_input, &typestruct);
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/*
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* Be obliging. but no work to do.
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*/
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static int
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ngipi_cons(node_p node)
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{
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return(0);
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}
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/*
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* Receive data
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*/
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static int
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ngipi_rcvdata(hook_p hook, item_p item)
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{
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struct mbuf *m;
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NGI_GET_M(item, m);
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NG_FREE_ITEM(item);
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if (curthread->td_ng_outbound)
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netisr_queue(NETISR_IP, m);
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else {
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struct epoch_tracker et;
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NET_EPOCH_ENTER(et);
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netisr_dispatch(NETISR_IP, m);
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NET_EPOCH_EXIT(et);
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}
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return 0;
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}
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/*
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* Hook disconnection
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*/
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static int
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ngipi_disconnect(hook_p hook)
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{
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if (NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
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ng_rmnode_self(NG_HOOK_NODE(hook));
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return (0);
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}
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