]>
Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* 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 | |
6aa20a22 | 14 | |
1da177e4 LT |
15 | [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 | ||
1da177e4 LT |
31 | #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> | |
206c9fb2 | 37 | #include <linux/rtnetlink.h> |
5d5cb173 | 38 | #include <net/rtnetlink.h> |
206c9fb2 | 39 | |
1da177e4 LT |
40 | static int numdummies = 1; |
41 | ||
42 | static int dummy_xmit(struct sk_buff *skb, struct net_device *dev); | |
1da177e4 LT |
43 | |
44 | static int dummy_set_address(struct net_device *dev, void *p) | |
45 | { | |
46 | struct sockaddr *sa = p; | |
47 | ||
6aa20a22 | 48 | if (!is_valid_ether_addr(sa->sa_data)) |
1da177e4 | 49 | return -EADDRNOTAVAIL; |
6aa20a22 | 50 | |
1da177e4 LT |
51 | memcpy(dev->dev_addr, sa->sa_data, ETH_ALEN); |
52 | return 0; | |
53 | } | |
54 | ||
55 | /* fake multicast ability */ | |
56 | static void set_multicast_list(struct net_device *dev) | |
57 | { | |
58 | } | |
59 | ||
aa18e9e8 SH |
60 | static const struct net_device_ops dummy_netdev_ops = { |
61 | .ndo_start_xmit = dummy_xmit, | |
62 | .ndo_validate_addr = eth_validate_addr, | |
63 | .ndo_set_multicast_list = set_multicast_list, | |
64 | .ndo_set_mac_address = dummy_set_address, | |
65 | }; | |
66 | ||
5d5cb173 | 67 | static void dummy_setup(struct net_device *dev) |
1da177e4 | 68 | { |
aa18e9e8 SH |
69 | ether_setup(dev); |
70 | ||
1da177e4 | 71 | /* Initialize the device structure. */ |
aa18e9e8 | 72 | dev->netdev_ops = &dummy_netdev_ops; |
5d5cb173 | 73 | dev->destructor = free_netdev; |
1da177e4 LT |
74 | |
75 | /* Fill in device structure with ethernet-generic values. */ | |
1da177e4 | 76 | dev->tx_queue_len = 0; |
1da177e4 LT |
77 | dev->flags |= IFF_NOARP; |
78 | dev->flags &= ~IFF_MULTICAST; | |
1da177e4 LT |
79 | random_ether_addr(dev->dev_addr); |
80 | } | |
81 | ||
82 | static int dummy_xmit(struct sk_buff *skb, struct net_device *dev) | |
83 | { | |
58651b24 PM |
84 | dev->stats.tx_packets++; |
85 | dev->stats.tx_bytes += skb->len; | |
1da177e4 LT |
86 | |
87 | dev_kfree_skb(skb); | |
88 | return 0; | |
89 | } | |
90 | ||
0e06877c PM |
91 | static int dummy_validate(struct nlattr *tb[], struct nlattr *data[]) |
92 | { | |
93 | if (tb[IFLA_ADDRESS]) { | |
94 | if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN) | |
95 | return -EINVAL; | |
96 | if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS]))) | |
97 | return -EADDRNOTAVAIL; | |
98 | } | |
99 | return 0; | |
100 | } | |
101 | ||
5d5cb173 PM |
102 | static struct rtnl_link_ops dummy_link_ops __read_mostly = { |
103 | .kind = "dummy", | |
5d5cb173 | 104 | .setup = dummy_setup, |
0e06877c | 105 | .validate = dummy_validate, |
5d5cb173 PM |
106 | }; |
107 | ||
1da177e4 LT |
108 | /* Number of dummy devices to be set up by this module. */ |
109 | module_param(numdummies, int, 0); | |
110 | MODULE_PARM_DESC(numdummies, "Number of dummy pseudo devices"); | |
111 | ||
206c9fb2 | 112 | static int __init dummy_init_one(void) |
1da177e4 LT |
113 | { |
114 | struct net_device *dev_dummy; | |
115 | int err; | |
116 | ||
2d85cba2 | 117 | dev_dummy = alloc_netdev(0, "dummy%d", dummy_setup); |
1da177e4 LT |
118 | if (!dev_dummy) |
119 | return -ENOMEM; | |
120 | ||
5d5cb173 PM |
121 | err = dev_alloc_name(dev_dummy, dev_dummy->name); |
122 | if (err < 0) | |
123 | goto err; | |
1da177e4 | 124 | |
5d5cb173 PM |
125 | dev_dummy->rtnl_link_ops = &dummy_link_ops; |
126 | err = register_netdevice(dev_dummy); | |
127 | if (err < 0) | |
128 | goto err; | |
5d5cb173 | 129 | return 0; |
206c9fb2 | 130 | |
5d5cb173 PM |
131 | err: |
132 | free_netdev(dev_dummy); | |
133 | return err; | |
6aa20a22 | 134 | } |
1da177e4 LT |
135 | |
136 | static int __init dummy_init_module(void) | |
6aa20a22 | 137 | { |
1da177e4 | 138 | int i, err = 0; |
206c9fb2 | 139 | |
5d5cb173 PM |
140 | rtnl_lock(); |
141 | err = __rtnl_link_register(&dummy_link_ops); | |
142 | ||
1da177e4 | 143 | for (i = 0; i < numdummies && !err; i++) |
206c9fb2 | 144 | err = dummy_init_one(); |
2d85cba2 | 145 | if (err < 0) |
5d5cb173 | 146 | __rtnl_link_unregister(&dummy_link_ops); |
5d5cb173 PM |
147 | rtnl_unlock(); |
148 | ||
1da177e4 | 149 | return err; |
6aa20a22 | 150 | } |
1da177e4 LT |
151 | |
152 | static void __exit dummy_cleanup_module(void) | |
153 | { | |
2d85cba2 | 154 | rtnl_link_unregister(&dummy_link_ops); |
1da177e4 LT |
155 | } |
156 | ||
157 | module_init(dummy_init_module); | |
158 | module_exit(dummy_cleanup_module); | |
159 | MODULE_LICENSE("GPL"); | |
5d5cb173 | 160 | MODULE_ALIAS_RTNL_LINK("dummy"); |