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![Ying Xue](/assets/img/avatar_default.png)
TIPC is currently using the field 'af_packet_priv' in struct net_device as a handle to find the bearer instance associated to the given network device. But, by doing so it is blocking other networking cleanups, such as the one discussed here: http://patchwork.ozlabs.org/patch/178044/ This commit removes this usage from TIPC. Instead, we introduce a new field, 'tipc_ptr', to the net_device structure, to serve this purpose. When TIPC bearer is enabled, the bearer object is associated to 'tipc_ptr'. When a TIPC packet arrives in the recv_msg() upcall from a networking device, the bearer object can now be obtained from 'tipc_ptr'. When a bearer is disabled, the bearer object is detached from its underlying network device by setting 'tipc_ptr' to NULL. Additionally, an RCU lock is used to protect the new pointer. Henceforth, the existing tipc_net_lock is used in write mode to serialize write accesses to this pointer, while the new RCU lock is applied on the read side to ensure that the pointer is 100% valid within its wrapped area for all readers. Signed-off-by: Ying Xue <ying.xue@windriver.com> Cc: Patrick McHardy <kaber@trash.net> Reviewed-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
371 lines
10 KiB
C
371 lines
10 KiB
C
/*
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* net/tipc/eth_media.c: Ethernet bearer support for TIPC
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*
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* Copyright (c) 2001-2007, 2013, Ericsson AB
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* Copyright (c) 2005-2008, 2011-2013, Wind River Systems
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* 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 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. Neither the names of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* Alternatively, this software may be distributed under the terms of the
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* GNU General Public License ("GPL") version 2 as published by the Free
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* Software Foundation.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND 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 COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "core.h"
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#include "bearer.h"
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#define MAX_ETH_MEDIA MAX_BEARERS
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#define ETH_ADDR_OFFSET 4 /* message header offset of MAC address */
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/**
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* struct eth_media - Ethernet bearer data structure
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* @bearer: ptr to associated "generic" bearer structure
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* @dev: ptr to associated Ethernet network device
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* @tipc_packet_type: used in binding TIPC to Ethernet driver
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* @setup: work item used when enabling bearer
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* @cleanup: work item used when disabling bearer
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*/
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struct eth_media {
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struct tipc_bearer *bearer;
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struct net_device *dev;
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struct packet_type tipc_packet_type;
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struct work_struct setup;
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struct work_struct cleanup;
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};
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static struct eth_media eth_media_array[MAX_ETH_MEDIA];
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static int eth_started;
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static int recv_notification(struct notifier_block *nb, unsigned long evt,
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void *dv);
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static int recv_msg(struct sk_buff *buf, struct net_device *dev,
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struct packet_type *pt, struct net_device *orig_dev);
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/*
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* Network device notifier info
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*/
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static struct notifier_block notifier = {
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.notifier_call = recv_notification,
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.priority = 0
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};
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static struct packet_type tipc_packet_type __read_mostly = {
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.type = __constant_htons(ETH_P_TIPC),
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.func = recv_msg,
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};
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/**
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* eth_media_addr_set - initialize Ethernet media address structure
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*
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* Media-dependent "value" field stores MAC address in first 6 bytes
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* and zeroes out the remaining bytes.
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*/
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static void eth_media_addr_set(const struct tipc_bearer *tb_ptr,
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struct tipc_media_addr *a, char *mac)
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{
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memcpy(a->value, mac, ETH_ALEN);
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memset(a->value + ETH_ALEN, 0, sizeof(a->value) - ETH_ALEN);
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a->media_id = TIPC_MEDIA_TYPE_ETH;
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a->broadcast = !memcmp(mac, tb_ptr->bcast_addr.value, ETH_ALEN);
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}
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/**
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* send_msg - send a TIPC message out over an Ethernet interface
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*/
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static int send_msg(struct sk_buff *buf, struct tipc_bearer *tb_ptr,
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struct tipc_media_addr *dest)
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{
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struct sk_buff *clone;
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struct net_device *dev;
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int delta;
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clone = skb_clone(buf, GFP_ATOMIC);
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if (!clone)
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return 0;
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dev = ((struct eth_media *)(tb_ptr->usr_handle))->dev;
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delta = dev->hard_header_len - skb_headroom(buf);
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if ((delta > 0) &&
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pskb_expand_head(clone, SKB_DATA_ALIGN(delta), 0, GFP_ATOMIC)) {
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kfree_skb(clone);
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return 0;
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}
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skb_reset_network_header(clone);
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clone->dev = dev;
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clone->protocol = htons(ETH_P_TIPC);
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dev_hard_header(clone, dev, ETH_P_TIPC, dest->value,
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dev->dev_addr, clone->len);
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dev_queue_xmit(clone);
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return 0;
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}
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/**
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* recv_msg - handle incoming TIPC message from an Ethernet interface
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*
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* Accept only packets explicitly sent to this node, or broadcast packets;
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* ignores packets sent using Ethernet multicast, and traffic sent to other
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* nodes (which can happen if interface is running in promiscuous mode).
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*/
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static int recv_msg(struct sk_buff *buf, struct net_device *dev,
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struct packet_type *pt, struct net_device *orig_dev)
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{
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struct tipc_bearer *b_ptr;
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if (!net_eq(dev_net(dev), &init_net)) {
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kfree_skb(buf);
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return NET_RX_DROP;
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}
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rcu_read_lock();
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b_ptr = rcu_dereference(dev->tipc_ptr);
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if (likely(b_ptr)) {
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if (likely(buf->pkt_type <= PACKET_BROADCAST)) {
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buf->next = NULL;
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tipc_recv_msg(buf, b_ptr);
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rcu_read_unlock();
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return NET_RX_SUCCESS;
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}
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}
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rcu_read_unlock();
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kfree_skb(buf);
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return NET_RX_DROP;
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}
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/**
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* setup_media - setup association between Ethernet bearer and interface
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*/
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static void setup_media(struct work_struct *work)
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{
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dev_add_pack(&tipc_packet_type);
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}
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/**
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* enable_media - attach TIPC bearer to an Ethernet interface
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*/
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static int enable_media(struct tipc_bearer *tb_ptr)
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{
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struct net_device *dev;
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struct eth_media *eb_ptr = ð_media_array[0];
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struct eth_media *stop = ð_media_array[MAX_ETH_MEDIA];
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char *driver_name = strchr((const char *)tb_ptr->name, ':') + 1;
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int pending_dev = 0;
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/* Find unused Ethernet bearer structure */
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while (eb_ptr->dev) {
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if (!eb_ptr->bearer)
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pending_dev++;
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if (++eb_ptr == stop)
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return pending_dev ? -EAGAIN : -EDQUOT;
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}
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/* Find device with specified name */
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dev = dev_get_by_name(&init_net, driver_name);
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if (!dev)
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return -ENODEV;
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/* Create Ethernet bearer for device */
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eb_ptr->dev = dev;
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INIT_WORK(&eb_ptr->setup, setup_media);
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schedule_work(&eb_ptr->setup);
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/* Associate TIPC bearer with Ethernet bearer */
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tb_ptr->dev = dev;
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eb_ptr->bearer = tb_ptr;
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tb_ptr->usr_handle = (void *)eb_ptr;
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memset(tb_ptr->bcast_addr.value, 0, sizeof(tb_ptr->bcast_addr.value));
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memcpy(tb_ptr->bcast_addr.value, dev->broadcast, ETH_ALEN);
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tb_ptr->bcast_addr.media_id = TIPC_MEDIA_TYPE_ETH;
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tb_ptr->bcast_addr.broadcast = 1;
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tb_ptr->mtu = dev->mtu;
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eth_media_addr_set(tb_ptr, &tb_ptr->addr, (char *)dev->dev_addr);
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rcu_assign_pointer(dev->tipc_ptr, tb_ptr);
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return 0;
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}
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/**
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* cleanup_media - break association between Ethernet bearer and interface
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*
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* This routine must be invoked from a work queue because it can sleep.
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*/
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static void cleanup_media(struct work_struct *work)
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{
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struct eth_media *eb_ptr =
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container_of(work, struct eth_media, cleanup);
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dev_remove_pack(&tipc_packet_type);
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dev_put(eb_ptr->dev);
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eb_ptr->dev = NULL;
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}
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/**
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* disable_media - detach TIPC bearer from an Ethernet interface
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*
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* Mark Ethernet bearer as inactive so that incoming buffers are thrown away,
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* then get worker thread to complete bearer cleanup. (Can't do cleanup
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* here because cleanup code needs to sleep and caller holds spinlocks.)
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*/
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static void disable_media(struct tipc_bearer *tb_ptr)
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{
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struct eth_media *eb_ptr = (struct eth_media *)tb_ptr->usr_handle;
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eb_ptr->bearer = NULL;
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INIT_WORK(&eb_ptr->cleanup, cleanup_media);
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schedule_work(&eb_ptr->cleanup);
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RCU_INIT_POINTER(tb_ptr->dev->tipc_ptr, NULL);
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}
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/**
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* recv_notification - handle device updates from OS
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*
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* Change the state of the Ethernet bearer (if any) associated with the
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* specified device.
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*/
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static int recv_notification(struct notifier_block *nb, unsigned long evt,
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void *ptr)
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{
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struct tipc_bearer *b_ptr;
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struct net_device *dev = netdev_notifier_info_to_dev(ptr);
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if (!net_eq(dev_net(dev), &init_net))
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return NOTIFY_DONE;
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rcu_read_lock();
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b_ptr = rcu_dereference(dev->tipc_ptr);
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if (!b_ptr) {
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rcu_read_unlock();
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return NOTIFY_DONE; /* bearer had been disabled */
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}
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b_ptr->mtu = dev->mtu;
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switch (evt) {
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case NETDEV_CHANGE:
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if (netif_carrier_ok(dev))
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break;
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case NETDEV_DOWN:
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case NETDEV_CHANGEMTU:
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case NETDEV_CHANGEADDR:
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tipc_reset_bearer(b_ptr);
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break;
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case NETDEV_UNREGISTER:
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case NETDEV_CHANGENAME:
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tipc_disable_bearer(b_ptr->name);
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break;
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}
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rcu_read_unlock();
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return NOTIFY_OK;
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}
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/**
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* eth_addr2str - convert Ethernet address to string
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*/
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static int eth_addr2str(struct tipc_media_addr *a, char *str_buf, int str_size)
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{
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if (str_size < 18) /* 18 = strlen("aa:bb:cc:dd:ee:ff\0") */
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return 1;
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sprintf(str_buf, "%pM", a->value);
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return 0;
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}
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/**
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* eth_str2addr - convert Ethernet address format to message header format
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*/
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static int eth_addr2msg(struct tipc_media_addr *a, char *msg_area)
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{
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memset(msg_area, 0, TIPC_MEDIA_ADDR_SIZE);
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msg_area[TIPC_MEDIA_TYPE_OFFSET] = TIPC_MEDIA_TYPE_ETH;
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memcpy(msg_area + ETH_ADDR_OFFSET, a->value, ETH_ALEN);
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return 0;
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}
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/**
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* eth_str2addr - convert message header address format to Ethernet format
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*/
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static int eth_msg2addr(const struct tipc_bearer *tb_ptr,
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struct tipc_media_addr *a, char *msg_area)
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{
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if (msg_area[TIPC_MEDIA_TYPE_OFFSET] != TIPC_MEDIA_TYPE_ETH)
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return 1;
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eth_media_addr_set(tb_ptr, a, msg_area + ETH_ADDR_OFFSET);
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return 0;
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}
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/*
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* Ethernet media registration info
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*/
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struct tipc_media eth_media_info = {
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.send_msg = send_msg,
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.enable_media = enable_media,
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.disable_media = disable_media,
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.addr2str = eth_addr2str,
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.addr2msg = eth_addr2msg,
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.msg2addr = eth_msg2addr,
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.priority = TIPC_DEF_LINK_PRI,
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.tolerance = TIPC_DEF_LINK_TOL,
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.window = TIPC_DEF_LINK_WIN,
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.type_id = TIPC_MEDIA_TYPE_ETH,
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.name = "eth"
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};
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/**
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* tipc_eth_media_start - activate Ethernet bearer support
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*
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* Register Ethernet media type with TIPC bearer code. Also register
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* with OS for notifications about device state changes.
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*/
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int tipc_eth_media_start(void)
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{
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int res;
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if (eth_started)
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return -EINVAL;
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res = register_netdevice_notifier(¬ifier);
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if (!res)
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eth_started = 1;
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return res;
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}
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/**
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* tipc_eth_media_stop - deactivate Ethernet bearer support
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*/
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void tipc_eth_media_stop(void)
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{
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if (!eth_started)
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return;
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flush_scheduled_work();
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unregister_netdevice_notifier(¬ifier);
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eth_started = 0;
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}
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