blob: da472c687481ab23ce0e6a9d0afa9c8733fd4ab8 [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;
Eric Dumazet7eebb0b2009-04-17 22:03:10 +000065 unsigned long drops;
Eric Dumazet5175c372006-10-18 20:51:57 -070066};
Linus Torvalds1da177e2005-04-16 15:20:36 -070067
Linus Torvalds1da177e2005-04-16 15:20:36 -070068/*
69 * The higher levels take care of making this non-reentrant (it's
70 * called with bh's disabled).
71 */
72static int loopback_xmit(struct sk_buff *skb, struct net_device *dev)
73{
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -070074 struct pcpu_lstats *pcpu_lstats, *lb_stats;
Eric Dumazet7eebb0b2009-04-17 22:03:10 +000075 int len;
Linus Torvalds1da177e2005-04-16 15:20:36 -070076
77 skb_orphan(skb);
78
Eric Dumazet7eebb0b2009-04-17 22:03:10 +000079 skb->protocol = eth_type_trans(skb, dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -070080
Eric W. Biederman9e0db4b2007-09-27 17:09:39 -070081 /* it's OK to use per_cpu_ptr() because BHs are off */
David S. Millere3c50d52008-07-15 02:58:39 -070082 pcpu_lstats = dev->ml_priv;
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -070083 lb_stats = per_cpu_ptr(pcpu_lstats, smp_processor_id());
Linus Torvalds1da177e2005-04-16 15:20:36 -070084
Eric Dumazet7eebb0b2009-04-17 22:03:10 +000085 len = skb->len;
86 if (likely(netif_rx(skb) == NET_RX_SUCCESS)) {
87 lb_stats->bytes += len;
88 lb_stats->packets++;
89 } else
90 lb_stats->drops++;
Linus Torvalds1da177e2005-04-16 15:20:36 -070091
Eric Dumazet58f53972006-10-20 00:32:41 -070092 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070093}
94
Stephen Hemmingerc02373b2008-11-19 21:46:18 -080095static struct net_device_stats *loopback_get_stats(struct net_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -070096{
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -070097 const struct pcpu_lstats *pcpu_lstats;
Eric Dumazet33036802007-04-10 13:25:40 -070098 struct net_device_stats *stats = &dev->stats;
Eric Dumazet5175c372006-10-18 20:51:57 -070099 unsigned long bytes = 0;
100 unsigned long packets = 0;
Eric Dumazet7eebb0b2009-04-17 22:03:10 +0000101 unsigned long drops = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102 int i;
103
David S. Millere3c50d52008-07-15 02:58:39 -0700104 pcpu_lstats = dev->ml_priv;
KAMEZAWA Hiroyuki0fed4842006-03-28 01:56:37 -0800105 for_each_possible_cpu(i) {
Eric Dumazet5175c372006-10-18 20:51:57 -0700106 const struct pcpu_lstats *lb_stats;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -0700108 lb_stats = per_cpu_ptr(pcpu_lstats, i);
Eric Dumazet5175c372006-10-18 20:51:57 -0700109 bytes += lb_stats->bytes;
110 packets += lb_stats->packets;
Eric Dumazet7eebb0b2009-04-17 22:03:10 +0000111 drops += lb_stats->drops;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112 }
Eric Dumazet5175c372006-10-18 20:51:57 -0700113 stats->rx_packets = packets;
114 stats->tx_packets = packets;
Eric Dumazet7eebb0b2009-04-17 22:03:10 +0000115 stats->rx_dropped = drops;
116 stats->rx_errors = drops;
117 stats->rx_bytes = bytes;
118 stats->tx_bytes = bytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 return stats;
120}
121
Stephen Hemminger7fa6b062006-09-27 20:33:34 -0700122static u32 always_on(struct net_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123{
124 return 1;
125}
126
Jeff Garzik7282d492006-09-13 14:30:00 -0400127static const struct ethtool_ops loopback_ethtool_ops = {
Stephen Hemminger7fa6b062006-09-27 20:33:34 -0700128 .get_link = always_on,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129 .set_tso = ethtool_op_set_tso,
Stephen Hemminger7fa6b062006-09-27 20:33:34 -0700130 .get_tx_csum = always_on,
131 .get_sg = always_on,
132 .get_rx_csum = always_on,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133};
134
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -0700135static int loopback_dev_init(struct net_device *dev)
136{
137 struct pcpu_lstats *lstats;
138
139 lstats = alloc_percpu(struct pcpu_lstats);
140 if (!lstats)
141 return -ENOMEM;
142
David S. Millere3c50d52008-07-15 02:58:39 -0700143 dev->ml_priv = lstats;
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -0700144 return 0;
145}
146
147static void loopback_dev_free(struct net_device *dev)
148{
David S. Millere3c50d52008-07-15 02:58:39 -0700149 struct pcpu_lstats *lstats = dev->ml_priv;
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -0700150
151 free_percpu(lstats);
152 free_netdev(dev);
153}
154
Stephen Hemmingerc02373b2008-11-19 21:46:18 -0800155static const struct net_device_ops loopback_ops = {
156 .ndo_init = loopback_dev_init,
Stephen Hemminger00829822008-11-20 20:14:53 -0800157 .ndo_start_xmit= loopback_xmit,
Stephen Hemmingerc02373b2008-11-19 21:46:18 -0800158 .ndo_get_stats = loopback_get_stats,
159};
160
Stephen Hemminger7fa6b062006-09-27 20:33:34 -0700161/*
Eric W. Biederman9e0db4b2007-09-27 17:09:39 -0700162 * The loopback device is special. There is only one instance
163 * per network namespace.
Stephen Hemminger7fa6b062006-09-27 20:33:34 -0700164 */
Daniel Lezcano854d8362007-09-25 19:18:04 -0700165static void loopback_setup(struct net_device *dev)
166{
Daniel Lezcano854d8362007-09-25 19:18:04 -0700167 dev->mtu = (16 * 1024) + 20 + 20 + 12;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700168 dev->hard_header_len = ETH_HLEN; /* 14 */
169 dev->addr_len = ETH_ALEN; /* 6 */
170 dev->tx_queue_len = 0;
171 dev->type = ARPHRD_LOOPBACK; /* 0x0001*/
Daniel Lezcano854d8362007-09-25 19:18:04 -0700172 dev->flags = IFF_LOOPBACK;
Eric Dumazet93f154b2009-05-18 22:19:19 -0700173 dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700174 dev->features = NETIF_F_SG | NETIF_F_FRAGLIST
Daniel Lezcano854d8362007-09-25 19:18:04 -0700175 | NETIF_F_TSO
Daniel Lezcano854d8362007-09-25 19:18:04 -0700176 | NETIF_F_NO_CSUM
177 | NETIF_F_HIGHDMA
178 | NETIF_F_LLTX
Emil Medve2d2c54e2007-12-27 08:17:22 -0600179 | NETIF_F_NETNS_LOCAL;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700180 dev->ethtool_ops = &loopback_ethtool_ops;
Stephen Hemminger3b04ddd2007-10-09 01:40:57 -0700181 dev->header_ops = &eth_header_ops;
Stephen Hemmingerc02373b2008-11-19 21:46:18 -0800182 dev->netdev_ops = &loopback_ops;
183 dev->destructor = loopback_dev_free;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700184}
Daniel Lezcanode3cb742007-09-25 19:16:28 -0700185
Ralf Baechle22783642005-08-18 14:05:18 -0700186/* Setup and register the loopback device. */
Pavel Emelyanov46650792007-10-08 20:38:39 -0700187static __net_init int loopback_net_init(struct net *net)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188{
Daniel Lezcano854d8362007-09-25 19:18:04 -0700189 struct net_device *dev;
190 int err;
Herbert Xuaeed9e82007-07-30 16:37:19 -0700191
Daniel Lezcano854d8362007-09-25 19:18:04 -0700192 err = -ENOMEM;
193 dev = alloc_netdev(0, "lo", loopback_setup);
194 if (!dev)
195 goto out;
196
YOSHIFUJI Hideakic346dca2008-03-25 21:47:49 +0900197 dev_net_set(dev, net);
Daniel Lezcano854d8362007-09-25 19:18:04 -0700198 err = register_netdev(dev);
199 if (err)
200 goto out_free_netdev;
201
Eric W. Biederman2774c7a2007-09-26 22:10:56 -0700202 net->loopback_dev = dev;
Pavel Emelyanov9d6dda32007-10-15 12:55:33 -0700203 return 0;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700204
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205
Daniel Lezcano854d8362007-09-25 19:18:04 -0700206out_free_netdev:
207 free_netdev(dev);
Pavel Emelyanov9d6dda32007-10-15 12:55:33 -0700208out:
209 if (net == &init_net)
210 panic("loopback: Failed to register netdevice: %d\n", err);
211 return err;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700212}
Adrian Bunk60903f22007-01-02 00:35:48 -0800213
Pavel Emelyanov46650792007-10-08 20:38:39 -0700214static __net_exit void loopback_net_exit(struct net *net)
Eric W. Biederman2774c7a2007-09-26 22:10:56 -0700215{
216 struct net_device *dev = net->loopback_dev;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700217
Eric W. Biederman2774c7a2007-09-26 22:10:56 -0700218 unregister_netdev(dev);
219}
220
Eric W. Biederman505d4f72008-11-07 22:54:20 -0800221/* Registered in net/core/dev.c */
222struct pernet_operations __net_initdata loopback_net_ops = {
Eric W. Biederman2774c7a2007-09-26 22:10:56 -0700223 .init = loopback_net_init,
224 .exit = loopback_net_exit,
225};