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![Eric W. Biederman](/assets/img/avatar_default.png)
Replace the bh safe variant with the hard irq safe variant. We need a hard irq safe variant to deal with netpoll transmitting packets from hard irq context, and we need it in most if not all of the places using the bh safe variant. Except on 32bit uni-processor the code is exactly the same so don't bother with a bh variant, just have a hard irq safe variant that everyone can use. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
212 lines
5 KiB
C
212 lines
5 KiB
C
/* dummy.c: a dummy net driver
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The purpose of this driver is to provide a device to point a
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route through, but not to actually transmit packets.
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Why? If you have a machine whose only connection is an occasional
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PPP/SLIP/PLIP link, you can only connect to your own hostname
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when the link is up. Otherwise you have to use localhost.
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This isn't very consistent.
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One solution is to set up a dummy link using PPP/SLIP/PLIP,
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but this seems (to me) too much overhead for too little gain.
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This driver provides a small alternative. Thus you can do
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[when not running slip]
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ifconfig dummy slip.addr.ess.here up
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[to go to slip]
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ifconfig dummy down
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dip whatever
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This was written by looking at Donald Becker's skeleton driver
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and the loopback driver. I then threw away anything that didn't
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apply! Thanks to Alan Cox for the key clue on what to do with
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misguided packets.
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Nick Holloway, 27th May 1994
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[I tweaked this explanation a little but that's all]
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Alan Cox, 30th May 1994
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/netdevice.h>
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#include <linux/etherdevice.h>
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#include <linux/init.h>
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#include <linux/moduleparam.h>
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#include <linux/rtnetlink.h>
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#include <net/rtnetlink.h>
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#include <linux/u64_stats_sync.h>
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static int numdummies = 1;
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/* fake multicast ability */
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static void set_multicast_list(struct net_device *dev)
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{
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}
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struct pcpu_dstats {
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u64 tx_packets;
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u64 tx_bytes;
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struct u64_stats_sync syncp;
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};
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static struct rtnl_link_stats64 *dummy_get_stats64(struct net_device *dev,
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struct rtnl_link_stats64 *stats)
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{
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int i;
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for_each_possible_cpu(i) {
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const struct pcpu_dstats *dstats;
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u64 tbytes, tpackets;
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unsigned int start;
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dstats = per_cpu_ptr(dev->dstats, i);
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do {
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start = u64_stats_fetch_begin_irq(&dstats->syncp);
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tbytes = dstats->tx_bytes;
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tpackets = dstats->tx_packets;
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} while (u64_stats_fetch_retry_irq(&dstats->syncp, start));
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stats->tx_bytes += tbytes;
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stats->tx_packets += tpackets;
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}
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return stats;
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}
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static netdev_tx_t dummy_xmit(struct sk_buff *skb, struct net_device *dev)
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{
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struct pcpu_dstats *dstats = this_cpu_ptr(dev->dstats);
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u64_stats_update_begin(&dstats->syncp);
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dstats->tx_packets++;
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dstats->tx_bytes += skb->len;
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u64_stats_update_end(&dstats->syncp);
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dev_kfree_skb(skb);
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return NETDEV_TX_OK;
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}
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static int dummy_dev_init(struct net_device *dev)
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{
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dev->dstats = netdev_alloc_pcpu_stats(struct pcpu_dstats);
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if (!dev->dstats)
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return -ENOMEM;
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return 0;
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}
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static void dummy_dev_uninit(struct net_device *dev)
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{
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free_percpu(dev->dstats);
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}
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static int dummy_change_carrier(struct net_device *dev, bool new_carrier)
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{
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if (new_carrier)
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netif_carrier_on(dev);
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else
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netif_carrier_off(dev);
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return 0;
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}
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static const struct net_device_ops dummy_netdev_ops = {
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.ndo_init = dummy_dev_init,
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.ndo_uninit = dummy_dev_uninit,
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.ndo_start_xmit = dummy_xmit,
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.ndo_validate_addr = eth_validate_addr,
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.ndo_set_rx_mode = set_multicast_list,
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.ndo_set_mac_address = eth_mac_addr,
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.ndo_get_stats64 = dummy_get_stats64,
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.ndo_change_carrier = dummy_change_carrier,
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};
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static void dummy_setup(struct net_device *dev)
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{
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ether_setup(dev);
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/* Initialize the device structure. */
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dev->netdev_ops = &dummy_netdev_ops;
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dev->destructor = free_netdev;
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/* Fill in device structure with ethernet-generic values. */
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dev->tx_queue_len = 0;
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dev->flags |= IFF_NOARP;
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dev->flags &= ~IFF_MULTICAST;
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dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
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dev->features |= NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_TSO;
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dev->features |= NETIF_F_HW_CSUM | NETIF_F_HIGHDMA | NETIF_F_LLTX;
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eth_hw_addr_random(dev);
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}
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static int dummy_validate(struct nlattr *tb[], struct nlattr *data[])
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{
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if (tb[IFLA_ADDRESS]) {
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if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
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return -EINVAL;
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if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
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return -EADDRNOTAVAIL;
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}
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return 0;
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}
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static struct rtnl_link_ops dummy_link_ops __read_mostly = {
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.kind = "dummy",
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.setup = dummy_setup,
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.validate = dummy_validate,
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};
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/* Number of dummy devices to be set up by this module. */
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module_param(numdummies, int, 0);
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MODULE_PARM_DESC(numdummies, "Number of dummy pseudo devices");
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static int __init dummy_init_one(void)
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{
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struct net_device *dev_dummy;
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int err;
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dev_dummy = alloc_netdev(0, "dummy%d", dummy_setup);
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if (!dev_dummy)
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return -ENOMEM;
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dev_dummy->rtnl_link_ops = &dummy_link_ops;
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err = register_netdevice(dev_dummy);
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if (err < 0)
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goto err;
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return 0;
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err:
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free_netdev(dev_dummy);
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return err;
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}
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static int __init dummy_init_module(void)
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{
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int i, err = 0;
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rtnl_lock();
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err = __rtnl_link_register(&dummy_link_ops);
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if (err < 0)
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goto out;
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for (i = 0; i < numdummies && !err; i++) {
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err = dummy_init_one();
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cond_resched();
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}
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if (err < 0)
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__rtnl_link_unregister(&dummy_link_ops);
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out:
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rtnl_unlock();
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return err;
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}
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static void __exit dummy_cleanup_module(void)
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{
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rtnl_link_unregister(&dummy_link_ops);
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}
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module_init(dummy_init_module);
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module_exit(dummy_cleanup_module);
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_RTNL_LINK("dummy");
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