blob: c260af5411d0ff06685487b8781de707562f7e28 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* dummy.c: a dummy net driver
2
3 The purpose of this driver is to provide a device to point a
4 route through, but not to actually transmit packets.
5
6 Why? If you have a machine whose only connection is an occasional
7 PPP/SLIP/PLIP link, you can only connect to your own hostname
8 when the link is up. Otherwise you have to use localhost.
9 This isn't very consistent.
10
11 One solution is to set up a dummy link using PPP/SLIP/PLIP,
12 but this seems (to me) too much overhead for too little gain.
13 This driver provides a small alternative. Thus you can do
Jeff Garzik6aa20a22006-09-13 13:24:59 -040014
Linus Torvalds1da177e2005-04-16 15:20:36 -070015 [when not running slip]
16 ifconfig dummy slip.addr.ess.here up
17 [to go to slip]
18 ifconfig dummy down
19 dip whatever
20
21 This was written by looking at Donald Becker's skeleton driver
22 and the loopback driver. I then threw away anything that didn't
23 apply! Thanks to Alan Cox for the key clue on what to do with
24 misguided packets.
25
26 Nick Holloway, 27th May 1994
27 [I tweaked this explanation a little but that's all]
28 Alan Cox, 30th May 1994
29*/
30
Linus Torvalds1da177e2005-04-16 15:20:36 -070031#include <linux/module.h>
32#include <linux/kernel.h>
33#include <linux/netdevice.h>
34#include <linux/etherdevice.h>
35#include <linux/init.h>
36#include <linux/moduleparam.h>
Patrick McHardy206c9fb2007-06-13 12:04:20 -070037#include <linux/rtnetlink.h>
Patrick McHardy5d5cb172007-06-13 12:04:34 -070038#include <net/rtnetlink.h>
Eric Dumazet6d81f412010-09-27 20:50:33 +000039#include <linux/u64_stats_sync.h>
Patrick McHardy206c9fb2007-06-13 12:04:20 -070040
Linus Torvalds1da177e2005-04-16 15:20:36 -070041static int numdummies = 1;
42
Linus Torvalds1da177e2005-04-16 15:20:36 -070043/* fake multicast ability */
44static void set_multicast_list(struct net_device *dev)
45{
46}
47
Eric Dumazet6d81f412010-09-27 20:50:33 +000048struct pcpu_dstats {
49 u64 tx_packets;
50 u64 tx_bytes;
51 struct u64_stats_sync syncp;
52};
53
54static struct rtnl_link_stats64 *dummy_get_stats64(struct net_device *dev,
55 struct rtnl_link_stats64 *stats)
56{
57 int i;
58
59 for_each_possible_cpu(i) {
60 const struct pcpu_dstats *dstats;
61 u64 tbytes, tpackets;
62 unsigned int start;
63
64 dstats = per_cpu_ptr(dev->dstats, i);
65 do {
Kevin Groenevelde3906482012-07-21 06:30:50 +000066 start = u64_stats_fetch_begin_bh(&dstats->syncp);
Eric Dumazet6d81f412010-09-27 20:50:33 +000067 tbytes = dstats->tx_bytes;
68 tpackets = dstats->tx_packets;
Kevin Groenevelde3906482012-07-21 06:30:50 +000069 } while (u64_stats_fetch_retry_bh(&dstats->syncp, start));
Eric Dumazet6d81f412010-09-27 20:50:33 +000070 stats->tx_bytes += tbytes;
71 stats->tx_packets += tpackets;
72 }
73 return stats;
74}
Stephen Hemminger424efe92009-08-31 19:50:51 +000075
76static netdev_tx_t dummy_xmit(struct sk_buff *skb, struct net_device *dev)
77{
Eric Dumazet6d81f412010-09-27 20:50:33 +000078 struct pcpu_dstats *dstats = this_cpu_ptr(dev->dstats);
79
80 u64_stats_update_begin(&dstats->syncp);
81 dstats->tx_packets++;
82 dstats->tx_bytes += skb->len;
83 u64_stats_update_end(&dstats->syncp);
Stephen Hemminger424efe92009-08-31 19:50:51 +000084
85 dev_kfree_skb(skb);
86 return NETDEV_TX_OK;
87}
88
Eric Dumazet6d81f412010-09-27 20:50:33 +000089static int dummy_dev_init(struct net_device *dev)
90{
91 dev->dstats = alloc_percpu(struct pcpu_dstats);
92 if (!dev->dstats)
93 return -ENOMEM;
94
95 return 0;
96}
97
Hiroaki SHIMODA890fdf22012-04-15 13:26:01 +000098static void dummy_dev_uninit(struct net_device *dev)
Eric Dumazet6d81f412010-09-27 20:50:33 +000099{
100 free_percpu(dev->dstats);
Eric Dumazet6d81f412010-09-27 20:50:33 +0000101}
102
Stephen Hemmingeraa18e9e2008-11-20 20:28:00 -0800103static const struct net_device_ops dummy_netdev_ops = {
Eric Dumazet6d81f412010-09-27 20:50:33 +0000104 .ndo_init = dummy_dev_init,
Hiroaki SHIMODA890fdf22012-04-15 13:26:01 +0000105 .ndo_uninit = dummy_dev_uninit,
Stephen Hemmingeraa18e9e2008-11-20 20:28:00 -0800106 .ndo_start_xmit = dummy_xmit,
107 .ndo_validate_addr = eth_validate_addr,
Jiri Pirkoafc4b132011-08-16 06:29:01 +0000108 .ndo_set_rx_mode = set_multicast_list,
Jiri Pirko0d1632b2012-06-29 05:10:08 +0000109 .ndo_set_mac_address = eth_mac_addr,
Eric Dumazet6d81f412010-09-27 20:50:33 +0000110 .ndo_get_stats64 = dummy_get_stats64,
Stephen Hemmingeraa18e9e2008-11-20 20:28:00 -0800111};
112
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700113static void dummy_setup(struct net_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114{
Stephen Hemmingeraa18e9e2008-11-20 20:28:00 -0800115 ether_setup(dev);
116
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117 /* Initialize the device structure. */
Stephen Hemmingeraa18e9e2008-11-20 20:28:00 -0800118 dev->netdev_ops = &dummy_netdev_ops;
Hiroaki SHIMODA890fdf22012-04-15 13:26:01 +0000119 dev->destructor = free_netdev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120
121 /* Fill in device structure with ethernet-generic values. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122 dev->tx_queue_len = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123 dev->flags |= IFF_NOARP;
124 dev->flags &= ~IFF_MULTICAST;
Jiri Pirko0d1632b2012-06-29 05:10:08 +0000125 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
Eric Dumazet6d81f412010-09-27 20:50:33 +0000126 dev->features |= NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_TSO;
Michał Mirosław34324dc2011-11-15 15:29:55 +0000127 dev->features |= NETIF_F_HW_CSUM | NETIF_F_HIGHDMA | NETIF_F_LLTX;
Danny Kukawka7ce5d222012-02-15 06:45:40 +0000128 eth_hw_addr_random(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129}
Eric Dumazet6d81f412010-09-27 20:50:33 +0000130
Patrick McHardy0e068772007-07-11 19:42:31 -0700131static int dummy_validate(struct nlattr *tb[], struct nlattr *data[])
132{
133 if (tb[IFLA_ADDRESS]) {
134 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
135 return -EINVAL;
136 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
137 return -EADDRNOTAVAIL;
138 }
139 return 0;
140}
141
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700142static struct rtnl_link_ops dummy_link_ops __read_mostly = {
143 .kind = "dummy",
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700144 .setup = dummy_setup,
Patrick McHardy0e068772007-07-11 19:42:31 -0700145 .validate = dummy_validate,
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700146};
147
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148/* Number of dummy devices to be set up by this module. */
149module_param(numdummies, int, 0);
150MODULE_PARM_DESC(numdummies, "Number of dummy pseudo devices");
151
Patrick McHardy206c9fb2007-06-13 12:04:20 -0700152static int __init dummy_init_one(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153{
154 struct net_device *dev_dummy;
155 int err;
156
Patrick McHardy2d85cba2007-07-11 19:42:13 -0700157 dev_dummy = alloc_netdev(0, "dummy%d", dummy_setup);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158 if (!dev_dummy)
159 return -ENOMEM;
160
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700161 dev_dummy->rtnl_link_ops = &dummy_link_ops;
162 err = register_netdevice(dev_dummy);
163 if (err < 0)
164 goto err;
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700165 return 0;
166
167err:
168 free_netdev(dev_dummy);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169 return err;
170}
171
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172static int __init dummy_init_module(void)
Jeff Garzik6aa20a22006-09-13 13:24:59 -0400173{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 int i, err = 0;
Patrick McHardy206c9fb2007-06-13 12:04:20 -0700175
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700176 rtnl_lock();
177 err = __rtnl_link_register(&dummy_link_ops);
178
Eric Dumazet16b0dc22012-06-10 21:11:57 +0000179 for (i = 0; i < numdummies && !err; i++) {
Patrick McHardy206c9fb2007-06-13 12:04:20 -0700180 err = dummy_init_one();
Eric Dumazet16b0dc22012-06-10 21:11:57 +0000181 cond_resched();
182 }
Patrick McHardy2d85cba2007-07-11 19:42:13 -0700183 if (err < 0)
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700184 __rtnl_link_unregister(&dummy_link_ops);
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700185 rtnl_unlock();
186
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187 return err;
Jeff Garzik6aa20a22006-09-13 13:24:59 -0400188}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189
190static void __exit dummy_cleanup_module(void)
191{
Patrick McHardy2d85cba2007-07-11 19:42:13 -0700192 rtnl_link_unregister(&dummy_link_ops);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193}
194
195module_init(dummy_init_module);
196module_exit(dummy_cleanup_module);
197MODULE_LICENSE("GPL");
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700198MODULE_ALIAS_RTNL_LINK("dummy");