blob: b9fcc9819837e7f79530ad11782272ea0f81a344 [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 */
Stephen Hemminger613573252009-08-31 19:50:58 +000072static netdev_tx_t loopback_xmit(struct sk_buff *skb,
73 struct net_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -070074{
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -070075 struct pcpu_lstats *pcpu_lstats, *lb_stats;
Eric Dumazet7eebb0b2009-04-17 22:03:10 +000076 int len;
Linus Torvalds1da177e2005-04-16 15:20:36 -070077
78 skb_orphan(skb);
79
Eric Dumazet7eebb0b2009-04-17 22:03:10 +000080 skb->protocol = eth_type_trans(skb, dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -070081
Eric W. Biederman9e0db4b2007-09-27 17:09:39 -070082 /* it's OK to use per_cpu_ptr() because BHs are off */
David S. Millere3c50d52008-07-15 02:58:39 -070083 pcpu_lstats = dev->ml_priv;
Christoph Lameterca0c9582009-10-03 19:48:22 +090084 lb_stats = this_cpu_ptr(pcpu_lstats);
Linus Torvalds1da177e2005-04-16 15:20:36 -070085
Eric Dumazet7eebb0b2009-04-17 22:03:10 +000086 len = skb->len;
87 if (likely(netif_rx(skb) == NET_RX_SUCCESS)) {
88 lb_stats->bytes += len;
89 lb_stats->packets++;
90 } else
91 lb_stats->drops++;
Linus Torvalds1da177e2005-04-16 15:20:36 -070092
Patrick McHardy6ed10652009-06-23 06:03:08 +000093 return NETDEV_TX_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -070094}
95
Stephen Hemmingerc02373b2008-11-19 21:46:18 -080096static struct net_device_stats *loopback_get_stats(struct net_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -070097{
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -070098 const struct pcpu_lstats *pcpu_lstats;
Eric Dumazet33036802007-04-10 13:25:40 -070099 struct net_device_stats *stats = &dev->stats;
Eric Dumazet5175c372006-10-18 20:51:57 -0700100 unsigned long bytes = 0;
101 unsigned long packets = 0;
Eric Dumazet7eebb0b2009-04-17 22:03:10 +0000102 unsigned long drops = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103 int i;
104
David S. Millere3c50d52008-07-15 02:58:39 -0700105 pcpu_lstats = dev->ml_priv;
KAMEZAWA Hiroyuki0fed4842006-03-28 01:56:37 -0800106 for_each_possible_cpu(i) {
Eric Dumazet5175c372006-10-18 20:51:57 -0700107 const struct pcpu_lstats *lb_stats;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -0700109 lb_stats = per_cpu_ptr(pcpu_lstats, i);
Eric Dumazet5175c372006-10-18 20:51:57 -0700110 bytes += lb_stats->bytes;
111 packets += lb_stats->packets;
Eric Dumazet7eebb0b2009-04-17 22:03:10 +0000112 drops += lb_stats->drops;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113 }
Eric Dumazet5175c372006-10-18 20:51:57 -0700114 stats->rx_packets = packets;
115 stats->tx_packets = packets;
Eric Dumazet7eebb0b2009-04-17 22:03:10 +0000116 stats->rx_dropped = drops;
117 stats->rx_errors = drops;
118 stats->rx_bytes = bytes;
119 stats->tx_bytes = bytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120 return stats;
121}
122
Stephen Hemminger7fa6b062006-09-27 20:33:34 -0700123static u32 always_on(struct net_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124{
125 return 1;
126}
127
Jeff Garzik7282d492006-09-13 14:30:00 -0400128static const struct ethtool_ops loopback_ethtool_ops = {
Stephen Hemminger7fa6b062006-09-27 20:33:34 -0700129 .get_link = always_on,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 .set_tso = ethtool_op_set_tso,
Stephen Hemminger7fa6b062006-09-27 20:33:34 -0700131 .get_tx_csum = always_on,
132 .get_sg = always_on,
133 .get_rx_csum = always_on,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134};
135
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -0700136static int loopback_dev_init(struct net_device *dev)
137{
138 struct pcpu_lstats *lstats;
139
140 lstats = alloc_percpu(struct pcpu_lstats);
141 if (!lstats)
142 return -ENOMEM;
143
David S. Millere3c50d52008-07-15 02:58:39 -0700144 dev->ml_priv = lstats;
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -0700145 return 0;
146}
147
148static void loopback_dev_free(struct net_device *dev)
149{
David S. Millere3c50d52008-07-15 02:58:39 -0700150 struct pcpu_lstats *lstats = dev->ml_priv;
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -0700151
152 free_percpu(lstats);
153 free_netdev(dev);
154}
155
Stephen Hemmingerc02373b2008-11-19 21:46:18 -0800156static const struct net_device_ops loopback_ops = {
157 .ndo_init = loopback_dev_init,
Stephen Hemminger00829822008-11-20 20:14:53 -0800158 .ndo_start_xmit= loopback_xmit,
Stephen Hemmingerc02373b2008-11-19 21:46:18 -0800159 .ndo_get_stats = loopback_get_stats,
160};
161
Stephen Hemminger7fa6b062006-09-27 20:33:34 -0700162/*
Eric W. Biederman9e0db4b2007-09-27 17:09:39 -0700163 * The loopback device is special. There is only one instance
164 * per network namespace.
Stephen Hemminger7fa6b062006-09-27 20:33:34 -0700165 */
Daniel Lezcano854d8362007-09-25 19:18:04 -0700166static void loopback_setup(struct net_device *dev)
167{
Daniel Lezcano854d8362007-09-25 19:18:04 -0700168 dev->mtu = (16 * 1024) + 20 + 20 + 12;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700169 dev->hard_header_len = ETH_HLEN; /* 14 */
170 dev->addr_len = ETH_ALEN; /* 6 */
171 dev->tx_queue_len = 0;
172 dev->type = ARPHRD_LOOPBACK; /* 0x0001*/
Daniel Lezcano854d8362007-09-25 19:18:04 -0700173 dev->flags = IFF_LOOPBACK;
Eric Dumazet93f154b2009-05-18 22:19:19 -0700174 dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700175 dev->features = NETIF_F_SG | NETIF_F_FRAGLIST
Daniel Lezcano854d8362007-09-25 19:18:04 -0700176 | NETIF_F_TSO
Daniel Lezcano854d8362007-09-25 19:18:04 -0700177 | NETIF_F_NO_CSUM
178 | NETIF_F_HIGHDMA
179 | NETIF_F_LLTX
Emil Medve2d2c54e2007-12-27 08:17:22 -0600180 | NETIF_F_NETNS_LOCAL;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700181 dev->ethtool_ops = &loopback_ethtool_ops;
Stephen Hemminger3b04ddd2007-10-09 01:40:57 -0700182 dev->header_ops = &eth_header_ops;
Stephen Hemmingerc02373b2008-11-19 21:46:18 -0800183 dev->netdev_ops = &loopback_ops;
184 dev->destructor = loopback_dev_free;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700185}
Daniel Lezcanode3cb742007-09-25 19:16:28 -0700186
Ralf Baechle22783642005-08-18 14:05:18 -0700187/* Setup and register the loopback device. */
Pavel Emelyanov46650792007-10-08 20:38:39 -0700188static __net_init int loopback_net_init(struct net *net)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189{
Daniel Lezcano854d8362007-09-25 19:18:04 -0700190 struct net_device *dev;
191 int err;
Herbert Xuaeed9e82007-07-30 16:37:19 -0700192
Daniel Lezcano854d8362007-09-25 19:18:04 -0700193 err = -ENOMEM;
194 dev = alloc_netdev(0, "lo", loopback_setup);
195 if (!dev)
196 goto out;
197
YOSHIFUJI Hideakic346dca2008-03-25 21:47:49 +0900198 dev_net_set(dev, net);
Daniel Lezcano854d8362007-09-25 19:18:04 -0700199 err = register_netdev(dev);
200 if (err)
201 goto out_free_netdev;
202
Eric W. Biederman2774c7a2007-09-26 22:10:56 -0700203 net->loopback_dev = dev;
Pavel Emelyanov9d6dda322007-10-15 12:55:33 -0700204 return 0;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700205
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206
Daniel Lezcano854d8362007-09-25 19:18:04 -0700207out_free_netdev:
208 free_netdev(dev);
Pavel Emelyanov9d6dda322007-10-15 12:55:33 -0700209out:
Octavian Purdila09ad9bc2009-11-25 15:14:13 -0800210 if (net_eq(net, &init_net))
Pavel Emelyanov9d6dda322007-10-15 12:55:33 -0700211 panic("loopback: Failed to register netdevice: %d\n", err);
212 return err;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700213}
Adrian Bunk60903f22007-01-02 00:35:48 -0800214
Eric W. Biederman505d4f72008-11-07 22:54:20 -0800215/* Registered in net/core/dev.c */
216struct pernet_operations __net_initdata loopback_net_ops = {
Eric W. Biederman2774c7a2007-09-26 22:10:56 -0700217 .init = loopback_net_init,
Eric W. Biederman2774c7a2007-09-26 22:10:56 -0700218};