blob: b7d438a367f36c15c495f1ff51ebb5b984cad5dc [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * Pseudo-driver for the loopback interface.
7 *
8 * Version: @(#)loopback.c 1.0.4b 08/16/93
9 *
Jesper Juhl02c30a82005-05-05 16:16:16 -070010 * Authors: Ross Biro
Linus Torvalds1da177e2005-04-16 15:20:36 -070011 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12 * Donald Becker, <becker@scyld.com>
13 *
14 * Alan Cox : Fixed oddments for NET3.014
15 * Alan Cox : Rejig for NET3.029 snap #3
16 * Alan Cox : Fixed NET3.029 bugs and sped up
17 * Larry McVoy : Tiny tweak to double performance
18 * Alan Cox : Backed out LMV's tweak - the linux mm
19 * can't take it...
20 * Michael Griffith: Don't bother computing the checksums
21 * on packets received on the loopback
22 * interface.
23 * Alexey Kuznetsov: Potential hang under some extreme
24 * cases removed.
25 *
26 * This program is free software; you can redistribute it and/or
27 * modify it under the terms of the GNU General Public License
28 * as published by the Free Software Foundation; either version
29 * 2 of the License, or (at your option) any later version.
30 */
31#include <linux/kernel.h>
32#include <linux/jiffies.h>
33#include <linux/module.h>
34#include <linux/interrupt.h>
35#include <linux/fs.h>
36#include <linux/types.h>
37#include <linux/string.h>
38#include <linux/socket.h>
39#include <linux/errno.h>
40#include <linux/fcntl.h>
41#include <linux/in.h>
42#include <linux/init.h>
43
44#include <asm/system.h>
45#include <asm/uaccess.h>
46#include <asm/io.h>
47
48#include <linux/inet.h>
49#include <linux/netdevice.h>
50#include <linux/etherdevice.h>
51#include <linux/skbuff.h>
52#include <linux/ethtool.h>
53#include <net/sock.h>
54#include <net/checksum.h>
55#include <linux/if_ether.h> /* For the statistics structure. */
56#include <linux/if_arp.h> /* For ARPHRD_ETHER */
57#include <linux/ip.h>
58#include <linux/tcp.h>
59#include <linux/percpu.h>
Eric W. Biederman2774c7a2007-09-26 22:10:56 -070060#include <net/net_namespace.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070061
Eric Dumazet5175c372006-10-18 20:51:57 -070062struct pcpu_lstats {
63 unsigned long packets;
64 unsigned long bytes;
65};
Linus Torvalds1da177e2005-04-16 15:20:36 -070066
Linus Torvalds1da177e2005-04-16 15:20:36 -070067/*
68 * The higher levels take care of making this non-reentrant (it's
69 * called with bh's disabled).
70 */
71static int loopback_xmit(struct sk_buff *skb, struct net_device *dev)
72{
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -070073 struct pcpu_lstats *pcpu_lstats, *lb_stats;
Linus Torvalds1da177e2005-04-16 15:20:36 -070074
75 skb_orphan(skb);
76
Chuck Ebbert0e920bf2005-07-02 21:28:23 -040077 skb->protocol = eth_type_trans(skb,dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -070078
Eric W. Biederman9e0db4b2007-09-27 17:09:39 -070079 /* it's OK to use per_cpu_ptr() because BHs are off */
David S. Millere3c50d52008-07-15 02:58:39 -070080 pcpu_lstats = dev->ml_priv;
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -070081 lb_stats = per_cpu_ptr(pcpu_lstats, smp_processor_id());
Eric Dumazet5175c372006-10-18 20:51:57 -070082 lb_stats->bytes += skb->len;
83 lb_stats->packets++;
Linus Torvalds1da177e2005-04-16 15:20:36 -070084
85 netif_rx(skb);
86
Eric Dumazet58f53972006-10-20 00:32:41 -070087 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070088}
89
Stephen Hemmingerc02373b2008-11-19 21:46:18 -080090static struct net_device_stats *loopback_get_stats(struct net_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -070091{
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -070092 const struct pcpu_lstats *pcpu_lstats;
Eric Dumazet33036802007-04-10 13:25:40 -070093 struct net_device_stats *stats = &dev->stats;
Eric Dumazet5175c372006-10-18 20:51:57 -070094 unsigned long bytes = 0;
95 unsigned long packets = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070096 int i;
97
David S. Millere3c50d52008-07-15 02:58:39 -070098 pcpu_lstats = dev->ml_priv;
KAMEZAWA Hiroyuki0fed4842006-03-28 01:56:37 -080099 for_each_possible_cpu(i) {
Eric Dumazet5175c372006-10-18 20:51:57 -0700100 const struct pcpu_lstats *lb_stats;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -0700102 lb_stats = per_cpu_ptr(pcpu_lstats, i);
Eric Dumazet5175c372006-10-18 20:51:57 -0700103 bytes += lb_stats->bytes;
104 packets += lb_stats->packets;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105 }
Eric Dumazet5175c372006-10-18 20:51:57 -0700106 stats->rx_packets = packets;
107 stats->tx_packets = packets;
108 stats->rx_bytes = bytes;
109 stats->tx_bytes = bytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110 return stats;
111}
112
Stephen Hemminger7fa6b062006-09-27 20:33:34 -0700113static u32 always_on(struct net_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114{
115 return 1;
116}
117
Jeff Garzik7282d492006-09-13 14:30:00 -0400118static const struct ethtool_ops loopback_ethtool_ops = {
Stephen Hemminger7fa6b062006-09-27 20:33:34 -0700119 .get_link = always_on,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120 .set_tso = ethtool_op_set_tso,
Stephen Hemminger7fa6b062006-09-27 20:33:34 -0700121 .get_tx_csum = always_on,
122 .get_sg = always_on,
123 .get_rx_csum = always_on,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124};
125
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -0700126static int loopback_dev_init(struct net_device *dev)
127{
128 struct pcpu_lstats *lstats;
129
130 lstats = alloc_percpu(struct pcpu_lstats);
131 if (!lstats)
132 return -ENOMEM;
133
David S. Millere3c50d52008-07-15 02:58:39 -0700134 dev->ml_priv = lstats;
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -0700135 return 0;
136}
137
138static void loopback_dev_free(struct net_device *dev)
139{
David S. Millere3c50d52008-07-15 02:58:39 -0700140 struct pcpu_lstats *lstats = dev->ml_priv;
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -0700141
142 free_percpu(lstats);
143 free_netdev(dev);
144}
145
Stephen Hemmingerc02373b2008-11-19 21:46:18 -0800146static const struct net_device_ops loopback_ops = {
147 .ndo_init = loopback_dev_init,
Stephen Hemminger00829822008-11-20 20:14:53 -0800148 .ndo_start_xmit= loopback_xmit,
Stephen Hemmingerc02373b2008-11-19 21:46:18 -0800149 .ndo_get_stats = loopback_get_stats,
150};
151
Stephen Hemminger7fa6b062006-09-27 20:33:34 -0700152/*
Eric W. Biederman9e0db4b2007-09-27 17:09:39 -0700153 * The loopback device is special. There is only one instance
154 * per network namespace.
Stephen Hemminger7fa6b062006-09-27 20:33:34 -0700155 */
Daniel Lezcano854d8362007-09-25 19:18:04 -0700156static void loopback_setup(struct net_device *dev)
157{
Daniel Lezcano854d8362007-09-25 19:18:04 -0700158 dev->mtu = (16 * 1024) + 20 + 20 + 12;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700159 dev->hard_header_len = ETH_HLEN; /* 14 */
160 dev->addr_len = ETH_ALEN; /* 6 */
161 dev->tx_queue_len = 0;
162 dev->type = ARPHRD_LOOPBACK; /* 0x0001*/
Daniel Lezcano854d8362007-09-25 19:18:04 -0700163 dev->flags = IFF_LOOPBACK;
164 dev->features = NETIF_F_SG | NETIF_F_FRAGLIST
Daniel Lezcano854d8362007-09-25 19:18:04 -0700165 | NETIF_F_TSO
Daniel Lezcano854d8362007-09-25 19:18:04 -0700166 | NETIF_F_NO_CSUM
167 | NETIF_F_HIGHDMA
168 | NETIF_F_LLTX
Emil Medve2d2c54e2007-12-27 08:17:22 -0600169 | NETIF_F_NETNS_LOCAL;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700170 dev->ethtool_ops = &loopback_ethtool_ops;
Stephen Hemminger3b04ddd2007-10-09 01:40:57 -0700171 dev->header_ops = &eth_header_ops;
Stephen Hemmingerc02373b2008-11-19 21:46:18 -0800172 dev->netdev_ops = &loopback_ops;
173 dev->destructor = loopback_dev_free;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700174}
Daniel Lezcanode3cb742007-09-25 19:16:28 -0700175
Ralf Baechle22783642005-08-18 14:05:18 -0700176/* Setup and register the loopback device. */
Pavel Emelyanov46650792007-10-08 20:38:39 -0700177static __net_init int loopback_net_init(struct net *net)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178{
Daniel Lezcano854d8362007-09-25 19:18:04 -0700179 struct net_device *dev;
180 int err;
Herbert Xuaeed9e82007-07-30 16:37:19 -0700181
Daniel Lezcano854d8362007-09-25 19:18:04 -0700182 err = -ENOMEM;
183 dev = alloc_netdev(0, "lo", loopback_setup);
184 if (!dev)
185 goto out;
186
YOSHIFUJI Hideakic346dca2008-03-25 21:47:49 +0900187 dev_net_set(dev, net);
Daniel Lezcano854d8362007-09-25 19:18:04 -0700188 err = register_netdev(dev);
189 if (err)
190 goto out_free_netdev;
191
Eric W. Biederman2774c7a2007-09-26 22:10:56 -0700192 net->loopback_dev = dev;
Pavel Emelyanov9d6dda322007-10-15 12:55:33 -0700193 return 0;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700194
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195
Daniel Lezcano854d8362007-09-25 19:18:04 -0700196out_free_netdev:
197 free_netdev(dev);
Pavel Emelyanov9d6dda322007-10-15 12:55:33 -0700198out:
199 if (net == &init_net)
200 panic("loopback: Failed to register netdevice: %d\n", err);
201 return err;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700202}
Adrian Bunk60903f22007-01-02 00:35:48 -0800203
Pavel Emelyanov46650792007-10-08 20:38:39 -0700204static __net_exit void loopback_net_exit(struct net *net)
Eric W. Biederman2774c7a2007-09-26 22:10:56 -0700205{
206 struct net_device *dev = net->loopback_dev;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700207
Eric W. Biederman2774c7a2007-09-26 22:10:56 -0700208 unregister_netdev(dev);
209}
210
Eric W. Biederman505d4f72008-11-07 22:54:20 -0800211/* Registered in net/core/dev.c */
212struct pernet_operations __net_initdata loopback_net_ops = {
Eric W. Biederman2774c7a2007-09-26 22:10:56 -0700213 .init = loopback_net_init,
214 .exit = loopback_net_exit,
215};