blob: 32eb94ece6c1b258497f9b12334c680729f48dc7 [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
Linus Torvalds1da177e2005-04-16 15:20:36 -070044#include <asm/uaccess.h>
45#include <asm/io.h>
46
47#include <linux/inet.h>
48#include <linux/netdevice.h>
49#include <linux/etherdevice.h>
50#include <linux/skbuff.h>
51#include <linux/ethtool.h>
52#include <net/sock.h>
53#include <net/checksum.h>
54#include <linux/if_ether.h> /* For the statistics structure. */
55#include <linux/if_arp.h> /* For ARPHRD_ETHER */
56#include <linux/ip.h>
57#include <linux/tcp.h>
58#include <linux/percpu.h>
Eric W. Biederman2774c7a2007-09-26 22:10:56 -070059#include <net/net_namespace.h>
Eric Dumazet5eaa0bd2010-06-22 12:44:11 +000060#include <linux/u64_stats_sync.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070061
Eric Dumazet5175c372006-10-18 20:51:57 -070062struct pcpu_lstats {
Eric Dumazet5eaa0bd2010-06-22 12:44:11 +000063 u64 packets;
64 u64 bytes;
65 struct u64_stats_sync syncp;
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{
Tejun Heo47d74272010-02-16 15:21:08 +000075 struct 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 */
Eric Dumazeta7855c72010-09-23 23:51:51 +000083 lb_stats = this_cpu_ptr(dev->lstats);
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)) {
Eric Dumazet5eaa0bd2010-06-22 12:44:11 +000087 u64_stats_update_begin(&lb_stats->syncp);
Eric Dumazet7eebb0b2009-04-17 22:03:10 +000088 lb_stats->bytes += len;
89 lb_stats->packets++;
Eric Dumazet5eaa0bd2010-06-22 12:44:11 +000090 u64_stats_update_end(&lb_stats->syncp);
Eric Dumazetcaf586e2010-09-30 21:06:55 +000091 }
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
Eric Dumazet28172732010-07-07 14:58:56 -070096static struct rtnl_link_stats64 *loopback_get_stats64(struct net_device *dev,
97 struct rtnl_link_stats64 *stats)
Linus Torvalds1da177e2005-04-16 15:20:36 -070098{
Eric Dumazet6b10de32010-06-14 05:59:22 +000099 u64 bytes = 0;
100 u64 packets = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 int i;
102
KAMEZAWA Hiroyuki0fed4842006-03-28 01:56:37 -0800103 for_each_possible_cpu(i) {
Eric Dumazet5175c372006-10-18 20:51:57 -0700104 const struct pcpu_lstats *lb_stats;
Eric Dumazet5eaa0bd2010-06-22 12:44:11 +0000105 u64 tbytes, tpackets;
106 unsigned int start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107
Eric Dumazeta7855c72010-09-23 23:51:51 +0000108 lb_stats = per_cpu_ptr(dev->lstats, i);
Eric Dumazet5eaa0bd2010-06-22 12:44:11 +0000109 do {
110 start = u64_stats_fetch_begin(&lb_stats->syncp);
111 tbytes = lb_stats->bytes;
112 tpackets = lb_stats->packets;
113 } while (u64_stats_fetch_retry(&lb_stats->syncp, start));
Eric Dumazet5eaa0bd2010-06-22 12:44:11 +0000114 bytes += tbytes;
115 packets += tpackets;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116 }
Eric Dumazet5175c372006-10-18 20:51:57 -0700117 stats->rx_packets = packets;
118 stats->tx_packets = packets;
Eric Dumazet7eebb0b2009-04-17 22:03:10 +0000119 stats->rx_bytes = bytes;
120 stats->tx_bytes = bytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121 return stats;
122}
123
Stephen Hemminger7fa6b062006-09-27 20:33:34 -0700124static u32 always_on(struct net_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125{
126 return 1;
127}
128
Jeff Garzik7282d492006-09-13 14:30:00 -0400129static const struct ethtool_ops loopback_ethtool_ops = {
Stephen Hemminger7fa6b062006-09-27 20:33:34 -0700130 .get_link = always_on,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131};
132
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -0700133static int loopback_dev_init(struct net_device *dev)
134{
Eric Dumazeta7855c72010-09-23 23:51:51 +0000135 dev->lstats = alloc_percpu(struct pcpu_lstats);
136 if (!dev->lstats)
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -0700137 return -ENOMEM;
138
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -0700139 return 0;
140}
141
142static void loopback_dev_free(struct net_device *dev)
143{
Eric Dumazeta7855c72010-09-23 23:51:51 +0000144 free_percpu(dev->lstats);
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -0700145 free_netdev(dev);
146}
147
Stephen Hemmingerc02373b2008-11-19 21:46:18 -0800148static const struct net_device_ops loopback_ops = {
149 .ndo_init = loopback_dev_init,
Stephen Hemminger00829822008-11-20 20:14:53 -0800150 .ndo_start_xmit= loopback_xmit,
Eric Dumazet6b10de32010-06-14 05:59:22 +0000151 .ndo_get_stats64 = loopback_get_stats64,
Stephen Hemmingerc02373b2008-11-19 21:46:18 -0800152};
153
Stephen Hemminger7fa6b062006-09-27 20:33:34 -0700154/*
Eric W. Biederman9e0db4b2007-09-27 17:09:39 -0700155 * The loopback device is special. There is only one instance
156 * per network namespace.
Stephen Hemminger7fa6b062006-09-27 20:33:34 -0700157 */
Daniel Lezcano854d8362007-09-25 19:18:04 -0700158static void loopback_setup(struct net_device *dev)
159{
Daniel Lezcano854d8362007-09-25 19:18:04 -0700160 dev->mtu = (16 * 1024) + 20 + 20 + 12;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700161 dev->hard_header_len = ETH_HLEN; /* 14 */
162 dev->addr_len = ETH_ALEN; /* 6 */
163 dev->tx_queue_len = 0;
164 dev->type = ARPHRD_LOOPBACK; /* 0x0001*/
Daniel Lezcano854d8362007-09-25 19:18:04 -0700165 dev->flags = IFF_LOOPBACK;
Eric Dumazet93f154b2009-05-18 22:19:19 -0700166 dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
Michał Mirosławcf0bdef2011-02-15 16:59:18 +0000167 dev->hw_features = NETIF_F_ALL_TSO | NETIF_F_UFO;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700168 dev->features = NETIF_F_SG | NETIF_F_FRAGLIST
Michał Mirosławcf0bdef2011-02-15 16:59:18 +0000169 | NETIF_F_ALL_TSO
170 | NETIF_F_UFO
Michał Mirosław34324dc2011-11-15 15:29:55 +0000171 | NETIF_F_HW_CSUM
Michał Mirosławcf0bdef2011-02-15 16:59:18 +0000172 | NETIF_F_RXCSUM
Daniel Lezcano854d8362007-09-25 19:18:04 -0700173 | NETIF_F_HIGHDMA
174 | NETIF_F_LLTX
Krishna Kumar0553c892011-04-14 06:07:04 +0000175 | NETIF_F_NETNS_LOCAL
Mahesh Bandewareed2a122011-05-04 15:30:11 +0000176 | NETIF_F_VLAN_CHALLENGED
177 | NETIF_F_LOOPBACK;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700178 dev->ethtool_ops = &loopback_ethtool_ops;
Stephen Hemminger3b04ddd2007-10-09 01:40:57 -0700179 dev->header_ops = &eth_header_ops;
Stephen Hemmingerc02373b2008-11-19 21:46:18 -0800180 dev->netdev_ops = &loopback_ops;
181 dev->destructor = loopback_dev_free;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700182}
Daniel Lezcanode3cb742007-09-25 19:16:28 -0700183
Ralf Baechle22783642005-08-18 14:05:18 -0700184/* Setup and register the loopback device. */
Pavel Emelyanov46650792007-10-08 20:38:39 -0700185static __net_init int loopback_net_init(struct net *net)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186{
Daniel Lezcano854d8362007-09-25 19:18:04 -0700187 struct net_device *dev;
188 int err;
Herbert Xuaeed9e82007-07-30 16:37:19 -0700189
Daniel Lezcano854d8362007-09-25 19:18:04 -0700190 err = -ENOMEM;
191 dev = alloc_netdev(0, "lo", loopback_setup);
192 if (!dev)
193 goto out;
194
YOSHIFUJI Hideakic346dca2008-03-25 21:47:49 +0900195 dev_net_set(dev, net);
Daniel Lezcano854d8362007-09-25 19:18:04 -0700196 err = register_netdev(dev);
197 if (err)
198 goto out_free_netdev;
199
Eric W. Biederman2774c7a2007-09-26 22:10:56 -0700200 net->loopback_dev = dev;
Pavel Emelyanov9d6dda322007-10-15 12:55:33 -0700201 return 0;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700202
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203
Daniel Lezcano854d8362007-09-25 19:18:04 -0700204out_free_netdev:
205 free_netdev(dev);
Pavel Emelyanov9d6dda322007-10-15 12:55:33 -0700206out:
Octavian Purdila09ad9bc2009-11-25 15:14:13 -0800207 if (net_eq(net, &init_net))
Pavel Emelyanov9d6dda322007-10-15 12:55:33 -0700208 panic("loopback: Failed to register netdevice: %d\n", err);
209 return err;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700210}
Adrian Bunk60903f22007-01-02 00:35:48 -0800211
Eric W. Biederman505d4f72008-11-07 22:54:20 -0800212/* Registered in net/core/dev.c */
213struct pernet_operations __net_initdata loopback_net_ops = {
Eric W. Biederman2774c7a2007-09-26 22:10:56 -0700214 .init = loopback_net_init,
Eric W. Biederman2774c7a2007-09-26 22:10:56 -0700215};