Blame view
drivers/net/dummy.c
4.85 KB
1da177e4c
|
1 2 3 4 5 6 7 8 9 10 11 12 13 |
/* dummy.c: a dummy net driver The purpose of this driver is to provide a device to point a route through, but not to actually transmit packets. Why? If you have a machine whose only connection is an occasional PPP/SLIP/PLIP link, you can only connect to your own hostname when the link is up. Otherwise you have to use localhost. This isn't very consistent. One solution is to set up a dummy link using PPP/SLIP/PLIP, but this seems (to me) too much overhead for too little gain. This driver provides a small alternative. Thus you can do |
6aa20a223
|
14 |
|
1da177e4c
|
15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 |
[when not running slip] ifconfig dummy slip.addr.ess.here up [to go to slip] ifconfig dummy down dip whatever This was written by looking at Donald Becker's skeleton driver and the loopback driver. I then threw away anything that didn't apply! Thanks to Alan Cox for the key clue on what to do with misguided packets. Nick Holloway, 27th May 1994 [I tweaked this explanation a little but that's all] Alan Cox, 30th May 1994 */ |
1da177e4c
|
30 31 32 33 34 35 |
#include <linux/module.h> #include <linux/kernel.h> #include <linux/netdevice.h> #include <linux/etherdevice.h> #include <linux/init.h> #include <linux/moduleparam.h> |
206c9fb26
|
36 |
#include <linux/rtnetlink.h> |
5d5cb173d
|
37 |
#include <net/rtnetlink.h> |
6d81f41c5
|
38 |
#include <linux/u64_stats_sync.h> |
206c9fb26
|
39 |
|
1da177e4c
|
40 |
static int numdummies = 1; |
1da177e4c
|
41 42 43 |
static int dummy_set_address(struct net_device *dev, void *p) { struct sockaddr *sa = p; |
6aa20a223
|
44 |
if (!is_valid_ether_addr(sa->sa_data)) |
1da177e4c
|
45 |
return -EADDRNOTAVAIL; |
6aa20a223
|
46 |
|
1da177e4c
|
47 48 49 50 51 52 53 54 |
memcpy(dev->dev_addr, sa->sa_data, ETH_ALEN); return 0; } /* fake multicast ability */ static void set_multicast_list(struct net_device *dev) { } |
6d81f41c5
|
55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 |
struct pcpu_dstats { u64 tx_packets; u64 tx_bytes; struct u64_stats_sync syncp; }; static struct rtnl_link_stats64 *dummy_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats) { int i; for_each_possible_cpu(i) { const struct pcpu_dstats *dstats; u64 tbytes, tpackets; unsigned int start; dstats = per_cpu_ptr(dev->dstats, i); do { start = u64_stats_fetch_begin(&dstats->syncp); tbytes = dstats->tx_bytes; tpackets = dstats->tx_packets; } while (u64_stats_fetch_retry(&dstats->syncp, start)); stats->tx_bytes += tbytes; stats->tx_packets += tpackets; } return stats; } |
424efe9ca
|
82 83 84 |
static netdev_tx_t dummy_xmit(struct sk_buff *skb, struct net_device *dev) { |
6d81f41c5
|
85 86 87 88 89 90 |
struct pcpu_dstats *dstats = this_cpu_ptr(dev->dstats); u64_stats_update_begin(&dstats->syncp); dstats->tx_packets++; dstats->tx_bytes += skb->len; u64_stats_update_end(&dstats->syncp); |
424efe9ca
|
91 92 93 94 |
dev_kfree_skb(skb); return NETDEV_TX_OK; } |
6d81f41c5
|
95 96 97 98 99 100 101 102 103 104 105 106 107 108 |
static int dummy_dev_init(struct net_device *dev) { dev->dstats = alloc_percpu(struct pcpu_dstats); if (!dev->dstats) return -ENOMEM; return 0; } static void dummy_dev_free(struct net_device *dev) { free_percpu(dev->dstats); free_netdev(dev); } |
aa18e9e88
|
109 |
static const struct net_device_ops dummy_netdev_ops = { |
6d81f41c5
|
110 |
.ndo_init = dummy_dev_init, |
aa18e9e88
|
111 112 |
.ndo_start_xmit = dummy_xmit, .ndo_validate_addr = eth_validate_addr, |
afc4b13df
|
113 |
.ndo_set_rx_mode = set_multicast_list, |
aa18e9e88
|
114 |
.ndo_set_mac_address = dummy_set_address, |
6d81f41c5
|
115 |
.ndo_get_stats64 = dummy_get_stats64, |
aa18e9e88
|
116 |
}; |
5d5cb173d
|
117 |
static void dummy_setup(struct net_device *dev) |
1da177e4c
|
118 |
{ |
aa18e9e88
|
119 |
ether_setup(dev); |
1da177e4c
|
120 |
/* Initialize the device structure. */ |
aa18e9e88
|
121 |
dev->netdev_ops = &dummy_netdev_ops; |
6d81f41c5
|
122 |
dev->destructor = dummy_dev_free; |
1da177e4c
|
123 124 |
/* Fill in device structure with ethernet-generic values. */ |
1da177e4c
|
125 |
dev->tx_queue_len = 0; |
1da177e4c
|
126 127 |
dev->flags |= IFF_NOARP; dev->flags &= ~IFF_MULTICAST; |
6d81f41c5
|
128 |
dev->features |= NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_TSO; |
34324dc2b
|
129 |
dev->features |= NETIF_F_HW_CSUM | NETIF_F_HIGHDMA | NETIF_F_LLTX; |
1da177e4c
|
130 131 |
random_ether_addr(dev->dev_addr); } |
6d81f41c5
|
132 |
|
0e06877c6
|
133 134 135 136 137 138 139 140 141 142 |
static int dummy_validate(struct nlattr *tb[], struct nlattr *data[]) { if (tb[IFLA_ADDRESS]) { if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN) return -EINVAL; if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS]))) return -EADDRNOTAVAIL; } return 0; } |
5d5cb173d
|
143 144 |
static struct rtnl_link_ops dummy_link_ops __read_mostly = { .kind = "dummy", |
5d5cb173d
|
145 |
.setup = dummy_setup, |
0e06877c6
|
146 |
.validate = dummy_validate, |
5d5cb173d
|
147 |
}; |
1da177e4c
|
148 149 150 |
/* Number of dummy devices to be set up by this module. */ module_param(numdummies, int, 0); MODULE_PARM_DESC(numdummies, "Number of dummy pseudo devices"); |
206c9fb26
|
151 |
static int __init dummy_init_one(void) |
1da177e4c
|
152 153 154 |
{ struct net_device *dev_dummy; int err; |
2d85cba2b
|
155 |
dev_dummy = alloc_netdev(0, "dummy%d", dummy_setup); |
1da177e4c
|
156 157 |
if (!dev_dummy) return -ENOMEM; |
5d5cb173d
|
158 159 160 161 |
dev_dummy->rtnl_link_ops = &dummy_link_ops; err = register_netdevice(dev_dummy); if (err < 0) goto err; |
5d5cb173d
|
162 |
return 0; |
206c9fb26
|
163 |
|
5d5cb173d
|
164 165 166 |
err: free_netdev(dev_dummy); return err; |
6aa20a223
|
167 |
} |
1da177e4c
|
168 169 |
static int __init dummy_init_module(void) |
6aa20a223
|
170 |
{ |
1da177e4c
|
171 |
int i, err = 0; |
206c9fb26
|
172 |
|
5d5cb173d
|
173 174 |
rtnl_lock(); err = __rtnl_link_register(&dummy_link_ops); |
1da177e4c
|
175 |
for (i = 0; i < numdummies && !err; i++) |
206c9fb26
|
176 |
err = dummy_init_one(); |
2d85cba2b
|
177 |
if (err < 0) |
5d5cb173d
|
178 |
__rtnl_link_unregister(&dummy_link_ops); |
5d5cb173d
|
179 |
rtnl_unlock(); |
1da177e4c
|
180 |
return err; |
6aa20a223
|
181 |
} |
1da177e4c
|
182 183 184 |
static void __exit dummy_cleanup_module(void) { |
2d85cba2b
|
185 |
rtnl_link_unregister(&dummy_link_ops); |
1da177e4c
|
186 187 188 189 190 |
} module_init(dummy_init_module); module_exit(dummy_cleanup_module); MODULE_LICENSE("GPL"); |
5d5cb173d
|
191 |
MODULE_ALIAS_RTNL_LINK("dummy"); |