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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
Flavio Leitnerc19be732014-12-05 22:13:24 -020041#define DRV_NAME "dummy"
42#define DRV_VERSION "1.0"
43
Linus Torvalds1da177e2005-04-16 15:20:36 -070044static int numdummies = 1;
45
Linus Torvalds1da177e2005-04-16 15:20:36 -070046/* fake multicast ability */
47static void set_multicast_list(struct net_device *dev)
48{
49}
50
Eric Dumazet6d81f412010-09-27 20:50:33 +000051struct pcpu_dstats {
52 u64 tx_packets;
53 u64 tx_bytes;
54 struct u64_stats_sync syncp;
55};
56
57static struct rtnl_link_stats64 *dummy_get_stats64(struct net_device *dev,
58 struct rtnl_link_stats64 *stats)
59{
60 int i;
61
62 for_each_possible_cpu(i) {
63 const struct pcpu_dstats *dstats;
64 u64 tbytes, tpackets;
65 unsigned int start;
66
67 dstats = per_cpu_ptr(dev->dstats, i);
68 do {
Eric W. Biederman57a77442014-03-13 21:26:42 -070069 start = u64_stats_fetch_begin_irq(&dstats->syncp);
Eric Dumazet6d81f412010-09-27 20:50:33 +000070 tbytes = dstats->tx_bytes;
71 tpackets = dstats->tx_packets;
Eric W. Biederman57a77442014-03-13 21:26:42 -070072 } while (u64_stats_fetch_retry_irq(&dstats->syncp, start));
Eric Dumazet6d81f412010-09-27 20:50:33 +000073 stats->tx_bytes += tbytes;
74 stats->tx_packets += tpackets;
75 }
76 return stats;
77}
Stephen Hemminger424efe92009-08-31 19:50:51 +000078
79static netdev_tx_t dummy_xmit(struct sk_buff *skb, struct net_device *dev)
80{
Eric Dumazet6d81f412010-09-27 20:50:33 +000081 struct pcpu_dstats *dstats = this_cpu_ptr(dev->dstats);
82
83 u64_stats_update_begin(&dstats->syncp);
84 dstats->tx_packets++;
85 dstats->tx_bytes += skb->len;
86 u64_stats_update_end(&dstats->syncp);
Stephen Hemminger424efe92009-08-31 19:50:51 +000087
88 dev_kfree_skb(skb);
89 return NETDEV_TX_OK;
90}
91
Eric Dumazet6d81f412010-09-27 20:50:33 +000092static int dummy_dev_init(struct net_device *dev)
93{
WANG Cong1c213bd2014-02-13 11:46:28 -080094 dev->dstats = netdev_alloc_pcpu_stats(struct pcpu_dstats);
Eric Dumazet6d81f412010-09-27 20:50:33 +000095 if (!dev->dstats)
96 return -ENOMEM;
97
98 return 0;
99}
100
Hiroaki SHIMODA890fdf22012-04-15 13:26:01 +0000101static void dummy_dev_uninit(struct net_device *dev)
Eric Dumazet6d81f412010-09-27 20:50:33 +0000102{
103 free_percpu(dev->dstats);
Eric Dumazet6d81f412010-09-27 20:50:33 +0000104}
105
Jiri Pirko210ab662012-12-27 23:49:40 +0000106static int dummy_change_carrier(struct net_device *dev, bool new_carrier)
107{
108 if (new_carrier)
109 netif_carrier_on(dev);
110 else
111 netif_carrier_off(dev);
112 return 0;
113}
114
Stephen Hemmingeraa18e9e2008-11-20 20:28:00 -0800115static const struct net_device_ops dummy_netdev_ops = {
Eric Dumazet6d81f412010-09-27 20:50:33 +0000116 .ndo_init = dummy_dev_init,
Hiroaki SHIMODA890fdf22012-04-15 13:26:01 +0000117 .ndo_uninit = dummy_dev_uninit,
Stephen Hemmingeraa18e9e2008-11-20 20:28:00 -0800118 .ndo_start_xmit = dummy_xmit,
119 .ndo_validate_addr = eth_validate_addr,
Jiri Pirkoafc4b132011-08-16 06:29:01 +0000120 .ndo_set_rx_mode = set_multicast_list,
Jiri Pirko0d1632b2012-06-29 05:10:08 +0000121 .ndo_set_mac_address = eth_mac_addr,
Eric Dumazet6d81f412010-09-27 20:50:33 +0000122 .ndo_get_stats64 = dummy_get_stats64,
Jiri Pirko210ab662012-12-27 23:49:40 +0000123 .ndo_change_carrier = dummy_change_carrier,
Stephen Hemmingeraa18e9e2008-11-20 20:28:00 -0800124};
125
Flavio Leitnerc19be732014-12-05 22:13:24 -0200126static void dummy_get_drvinfo(struct net_device *dev,
127 struct ethtool_drvinfo *info)
128{
129 strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
130 strlcpy(info->version, DRV_VERSION, sizeof(info->version));
131}
132
133static const struct ethtool_ops dummy_ethtool_ops = {
134 .get_drvinfo = dummy_get_drvinfo,
135};
136
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700137static void dummy_setup(struct net_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138{
Stephen Hemmingeraa18e9e2008-11-20 20:28:00 -0800139 ether_setup(dev);
140
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 /* Initialize the device structure. */
Stephen Hemmingeraa18e9e2008-11-20 20:28:00 -0800142 dev->netdev_ops = &dummy_netdev_ops;
Flavio Leitnerc19be732014-12-05 22:13:24 -0200143 dev->ethtool_ops = &dummy_ethtool_ops;
Hiroaki SHIMODA890fdf22012-04-15 13:26:01 +0000144 dev->destructor = free_netdev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145
146 /* Fill in device structure with ethernet-generic values. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147 dev->tx_queue_len = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148 dev->flags |= IFF_NOARP;
149 dev->flags &= ~IFF_MULTICAST;
Jiri Pirko0d1632b2012-06-29 05:10:08 +0000150 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
Eric Dumazet6d81f412010-09-27 20:50:33 +0000151 dev->features |= NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_TSO;
Michał Mirosław34324dc2011-11-15 15:29:55 +0000152 dev->features |= NETIF_F_HW_CSUM | NETIF_F_HIGHDMA | NETIF_F_LLTX;
Danny Kukawka7ce5d222012-02-15 06:45:40 +0000153 eth_hw_addr_random(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154}
Eric Dumazet6d81f412010-09-27 20:50:33 +0000155
Patrick McHardy0e068772007-07-11 19:42:31 -0700156static int dummy_validate(struct nlattr *tb[], struct nlattr *data[])
157{
158 if (tb[IFLA_ADDRESS]) {
159 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
160 return -EINVAL;
161 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
162 return -EADDRNOTAVAIL;
163 }
164 return 0;
165}
166
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700167static struct rtnl_link_ops dummy_link_ops __read_mostly = {
Flavio Leitnerc19be732014-12-05 22:13:24 -0200168 .kind = DRV_NAME,
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700169 .setup = dummy_setup,
Patrick McHardy0e068772007-07-11 19:42:31 -0700170 .validate = dummy_validate,
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700171};
172
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173/* Number of dummy devices to be set up by this module. */
174module_param(numdummies, int, 0);
175MODULE_PARM_DESC(numdummies, "Number of dummy pseudo devices");
176
Patrick McHardy206c9fb2007-06-13 12:04:20 -0700177static int __init dummy_init_one(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178{
179 struct net_device *dev_dummy;
180 int err;
181
Tom Gundersenc835a672014-07-14 16:37:24 +0200182 dev_dummy = alloc_netdev(0, "dummy%d", NET_NAME_UNKNOWN, dummy_setup);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183 if (!dev_dummy)
184 return -ENOMEM;
185
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700186 dev_dummy->rtnl_link_ops = &dummy_link_ops;
187 err = register_netdevice(dev_dummy);
188 if (err < 0)
189 goto err;
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700190 return 0;
191
192err:
193 free_netdev(dev_dummy);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194 return err;
195}
196
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197static int __init dummy_init_module(void)
Jeff Garzik6aa20a22006-09-13 13:24:59 -0400198{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199 int i, err = 0;
Patrick McHardy206c9fb2007-06-13 12:04:20 -0700200
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700201 rtnl_lock();
202 err = __rtnl_link_register(&dummy_link_ops);
dingtianhong2c8a0182013-07-11 19:04:02 +0800203 if (err < 0)
204 goto out;
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700205
Eric Dumazet16b0dc22012-06-10 21:11:57 +0000206 for (i = 0; i < numdummies && !err; i++) {
Patrick McHardy206c9fb2007-06-13 12:04:20 -0700207 err = dummy_init_one();
Eric Dumazet16b0dc22012-06-10 21:11:57 +0000208 cond_resched();
209 }
Patrick McHardy2d85cba2007-07-11 19:42:13 -0700210 if (err < 0)
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700211 __rtnl_link_unregister(&dummy_link_ops);
dingtianhong2c8a0182013-07-11 19:04:02 +0800212
213out:
Patrick McHardy5d5cb172007-06-13 12:04:34 -0700214 rtnl_unlock();
215
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 return err;
Jeff Garzik6aa20a22006-09-13 13:24:59 -0400217}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218
219static void __exit dummy_cleanup_module(void)
220{
Patrick McHardy2d85cba2007-07-11 19:42:13 -0700221 rtnl_link_unregister(&dummy_link_ops);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222}
223
224module_init(dummy_init_module);
225module_exit(dummy_cleanup_module);
226MODULE_LICENSE("GPL");
Flavio Leitnerc19be732014-12-05 22:13:24 -0200227MODULE_ALIAS_RTNL_LINK(DRV_NAME);