blob: ff435fbd1ad0e8b32a8299211a890b1f5b9deb31 [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 {
Eric W. Biederman57a77442014-03-13 21:26:42 -070066 start = u64_stats_fetch_begin_irq(&dstats->syncp);
Eric Dumazet6d81f412010-09-27 20:50:33 +000067 tbytes = dstats->tx_bytes;
68 tpackets = dstats->tx_packets;
Eric W. Biederman57a77442014-03-13 21:26:42 -070069 } while (u64_stats_fetch_retry_irq(&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{
WANG Cong1c213bd2014-02-13 11:46:28 -080091 dev->dstats = netdev_alloc_pcpu_stats(struct pcpu_dstats);
Eric Dumazet6d81f412010-09-27 20:50:33 +000092 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
Jiri Pirko210ab662012-12-27 23:49:40 +0000103static int dummy_change_carrier(struct net_device *dev, bool new_carrier)
104{
105 if (new_carrier)
106 netif_carrier_on(dev);
107 else
108 netif_carrier_off(dev);
109 return 0;
110}
111
Stephen Hemmingeraa18e9e2008-11-20 20:28:00 -0800112static const struct net_device_ops dummy_netdev_ops = {
Eric Dumazet6d81f412010-09-27 20:50:33 +0000113 .ndo_init = dummy_dev_init,
Hiroaki SHIMODA890fdf22012-04-15 13:26:01 +0000114 .ndo_uninit = dummy_dev_uninit,
Stephen Hemmingeraa18e9e2008-11-20 20:28:00 -0800115 .ndo_start_xmit = dummy_xmit,
116 .ndo_validate_addr = eth_validate_addr,
Jiri Pirkoafc4b132011-08-16 06:29:01 +0000117 .ndo_set_rx_mode = set_multicast_list,
Jiri Pirko0d1632b2012-06-29 05:10:08 +0000118 .ndo_set_mac_address = eth_mac_addr,
Eric Dumazet6d81f412010-09-27 20:50:33 +0000119 .ndo_get_stats64 = dummy_get_stats64,
Jiri Pirko210ab662012-12-27 23:49:40 +0000120 .ndo_change_carrier = dummy_change_carrier,
Stephen Hemmingeraa18e9e2008-11-20 20:28:00 -0800121};
122
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700123static void dummy_setup(struct net_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124{
Stephen Hemmingeraa18e9e2008-11-20 20:28:00 -0800125 ether_setup(dev);
126
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127 /* Initialize the device structure. */
Stephen Hemmingeraa18e9e2008-11-20 20:28:00 -0800128 dev->netdev_ops = &dummy_netdev_ops;
Hiroaki SHIMODA890fdf22012-04-15 13:26:01 +0000129 dev->destructor = free_netdev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130
131 /* Fill in device structure with ethernet-generic values. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132 dev->tx_queue_len = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 dev->flags |= IFF_NOARP;
134 dev->flags &= ~IFF_MULTICAST;
Jiri Pirko0d1632b2012-06-29 05:10:08 +0000135 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
Eric Dumazet6d81f412010-09-27 20:50:33 +0000136 dev->features |= NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_TSO;
Michał Mirosław34324dc2011-11-15 15:29:55 +0000137 dev->features |= NETIF_F_HW_CSUM | NETIF_F_HIGHDMA | NETIF_F_LLTX;
Danny Kukawka7ce5d222012-02-15 06:45:40 +0000138 eth_hw_addr_random(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139}
Eric Dumazet6d81f412010-09-27 20:50:33 +0000140
Patrick McHardy0e068772007-07-11 19:42:31 -0700141static int dummy_validate(struct nlattr *tb[], struct nlattr *data[])
142{
143 if (tb[IFLA_ADDRESS]) {
144 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
145 return -EINVAL;
146 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
147 return -EADDRNOTAVAIL;
148 }
149 return 0;
150}
151
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700152static struct rtnl_link_ops dummy_link_ops __read_mostly = {
153 .kind = "dummy",
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700154 .setup = dummy_setup,
Patrick McHardy0e068772007-07-11 19:42:31 -0700155 .validate = dummy_validate,
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700156};
157
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158/* Number of dummy devices to be set up by this module. */
159module_param(numdummies, int, 0);
160MODULE_PARM_DESC(numdummies, "Number of dummy pseudo devices");
161
Patrick McHardy206c9fb2007-06-13 12:04:20 -0700162static int __init dummy_init_one(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163{
164 struct net_device *dev_dummy;
165 int err;
166
Tom Gundersenc835a672014-07-14 16:37:24 +0200167 dev_dummy = alloc_netdev(0, "dummy%d", NET_NAME_UNKNOWN, dummy_setup);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168 if (!dev_dummy)
169 return -ENOMEM;
170
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700171 dev_dummy->rtnl_link_ops = &dummy_link_ops;
172 err = register_netdevice(dev_dummy);
173 if (err < 0)
174 goto err;
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700175 return 0;
176
177err:
178 free_netdev(dev_dummy);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179 return err;
180}
181
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182static int __init dummy_init_module(void)
Jeff Garzik6aa20a22006-09-13 13:24:59 -0400183{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184 int i, err = 0;
Patrick McHardy206c9fb2007-06-13 12:04:20 -0700185
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700186 rtnl_lock();
187 err = __rtnl_link_register(&dummy_link_ops);
dingtianhong2c8a0182013-07-11 19:04:02 +0800188 if (err < 0)
189 goto out;
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700190
Eric Dumazet16b0dc22012-06-10 21:11:57 +0000191 for (i = 0; i < numdummies && !err; i++) {
Patrick McHardy206c9fb2007-06-13 12:04:20 -0700192 err = dummy_init_one();
Eric Dumazet16b0dc22012-06-10 21:11:57 +0000193 cond_resched();
194 }
Patrick McHardy2d85cba2007-07-11 19:42:13 -0700195 if (err < 0)
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700196 __rtnl_link_unregister(&dummy_link_ops);
dingtianhong2c8a0182013-07-11 19:04:02 +0800197
198out:
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700199 rtnl_unlock();
200
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 return err;
Jeff Garzik6aa20a22006-09-13 13:24:59 -0400202}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203
204static void __exit dummy_cleanup_module(void)
205{
Patrick McHardy2d85cba2007-07-11 19:42:13 -0700206 rtnl_link_unregister(&dummy_link_ops);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207}
208
209module_init(dummy_init_module);
210module_exit(dummy_cleanup_module);
211MODULE_LICENSE("GPL");
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700212MODULE_ALIAS_RTNL_LINK("dummy");