blob: a17d85a331f1ade54f9ec1834f1e8ee1c67d9b9d [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 Dumazet5175c3782006-10-18 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 Dumazet5175c3782006-10-18 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 Dumazet794ed392013-01-25 07:44:41 +000080 /* Before queueing this packet to netif_rx(),
81 * make sure dst is refcounted.
82 */
83 skb_dst_force(skb);
84
Eric Dumazet7eebb0b2009-04-17 22:03:10 +000085 skb->protocol = eth_type_trans(skb, dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -070086
Eric W. Biederman9e0db4b2007-09-27 17:09:39 -070087 /* it's OK to use per_cpu_ptr() because BHs are off */
Eric Dumazeta7855c72010-09-23 23:51:51 +000088 lb_stats = this_cpu_ptr(dev->lstats);
Linus Torvalds1da177e2005-04-16 15:20:36 -070089
Eric Dumazet7eebb0b2009-04-17 22:03:10 +000090 len = skb->len;
91 if (likely(netif_rx(skb) == NET_RX_SUCCESS)) {
Eric Dumazet5eaa0bd2010-06-22 12:44:11 +000092 u64_stats_update_begin(&lb_stats->syncp);
Eric Dumazet7eebb0b2009-04-17 22:03:10 +000093 lb_stats->bytes += len;
94 lb_stats->packets++;
Eric Dumazet5eaa0bd2010-06-22 12:44:11 +000095 u64_stats_update_end(&lb_stats->syncp);
Eric Dumazetcaf586e2010-09-30 21:06:55 +000096 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070097
Patrick McHardy6ed10652009-06-23 06:03:08 +000098 return NETDEV_TX_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -070099}
100
Eric Dumazet28172732010-07-07 14:58:56 -0700101static struct rtnl_link_stats64 *loopback_get_stats64(struct net_device *dev,
102 struct rtnl_link_stats64 *stats)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103{
Eric Dumazet6b10de32010-06-14 05:59:22 +0000104 u64 bytes = 0;
105 u64 packets = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106 int i;
107
KAMEZAWA Hiroyuki0fed4842006-03-28 01:56:37 -0800108 for_each_possible_cpu(i) {
Eric Dumazet5175c3782006-10-18 20:51:57 -0700109 const struct pcpu_lstats *lb_stats;
Eric Dumazet5eaa0bd2010-06-22 12:44:11 +0000110 u64 tbytes, tpackets;
111 unsigned int start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112
Eric Dumazeta7855c72010-09-23 23:51:51 +0000113 lb_stats = per_cpu_ptr(dev->lstats, i);
Eric Dumazet5eaa0bd2010-06-22 12:44:11 +0000114 do {
Kevin Groenevelde3906482012-07-21 06:30:50 +0000115 start = u64_stats_fetch_begin_bh(&lb_stats->syncp);
Eric Dumazet5eaa0bd2010-06-22 12:44:11 +0000116 tbytes = lb_stats->bytes;
117 tpackets = lb_stats->packets;
Kevin Groenevelde3906482012-07-21 06:30:50 +0000118 } while (u64_stats_fetch_retry_bh(&lb_stats->syncp, start));
Eric Dumazet5eaa0bd2010-06-22 12:44:11 +0000119 bytes += tbytes;
120 packets += tpackets;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121 }
Eric Dumazet5175c3782006-10-18 20:51:57 -0700122 stats->rx_packets = packets;
123 stats->tx_packets = packets;
Eric Dumazet7eebb0b2009-04-17 22:03:10 +0000124 stats->rx_bytes = bytes;
125 stats->tx_bytes = bytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126 return stats;
127}
128
Stephen Hemminger7fa6b062006-09-27 20:33:34 -0700129static u32 always_on(struct net_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130{
131 return 1;
132}
133
Jeff Garzik7282d492006-09-13 14:30:00 -0400134static const struct ethtool_ops loopback_ethtool_ops = {
Stephen Hemminger7fa6b062006-09-27 20:33:34 -0700135 .get_link = always_on,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136};
137
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -0700138static int loopback_dev_init(struct net_device *dev)
139{
Eric Dumazeta7855c72010-09-23 23:51:51 +0000140 dev->lstats = alloc_percpu(struct pcpu_lstats);
141 if (!dev->lstats)
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -0700142 return -ENOMEM;
143
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -0700144 return 0;
145}
146
147static void loopback_dev_free(struct net_device *dev)
148{
Eric W. Biedermane05e9072013-09-16 16:52:41 -0700149 dev_net(dev)->loopback_dev = NULL;
Eric Dumazeta7855c72010-09-23 23:51:51 +0000150 free_percpu(dev->lstats);
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -0700151 free_netdev(dev);
152}
153
Stephen Hemmingerc02373bf2008-11-19 21:46:18 -0800154static const struct net_device_ops loopback_ops = {
155 .ndo_init = loopback_dev_init,
Stephen Hemminger00829822008-11-20 20:14:53 -0800156 .ndo_start_xmit= loopback_xmit,
Eric Dumazet6b10de32010-06-14 05:59:22 +0000157 .ndo_get_stats64 = loopback_get_stats64,
Stephen Hemmingerc02373bf2008-11-19 21:46:18 -0800158};
159
Stephen Hemminger7fa6b062006-09-27 20:33:34 -0700160/*
Eric W. Biederman9e0db4b2007-09-27 17:09:39 -0700161 * The loopback device is special. There is only one instance
162 * per network namespace.
Stephen Hemminger7fa6b062006-09-27 20:33:34 -0700163 */
Daniel Lezcano854d8362007-09-25 19:18:04 -0700164static void loopback_setup(struct net_device *dev)
165{
Eric Dumazet0cf833a2012-09-23 22:28:59 +0000166 dev->mtu = 64 * 1024;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700167 dev->hard_header_len = ETH_HLEN; /* 14 */
168 dev->addr_len = ETH_ALEN; /* 6 */
169 dev->tx_queue_len = 0;
170 dev->type = ARPHRD_LOOPBACK; /* 0x0001*/
Daniel Lezcano854d8362007-09-25 19:18:04 -0700171 dev->flags = IFF_LOOPBACK;
Eric Dumazet93f154b2009-05-18 22:19:19 -0700172 dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
Michał Mirosławcf0bdef2011-02-15 16:59:18 +0000173 dev->hw_features = NETIF_F_ALL_TSO | NETIF_F_UFO;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700174 dev->features = NETIF_F_SG | NETIF_F_FRAGLIST
Michał Mirosławcf0bdef2011-02-15 16:59:18 +0000175 | NETIF_F_ALL_TSO
176 | NETIF_F_UFO
Michał Mirosław34324dc2011-11-15 15:29:55 +0000177 | NETIF_F_HW_CSUM
Michał Mirosławcf0bdef2011-02-15 16:59:18 +0000178 | NETIF_F_RXCSUM
Daniel Lezcano854d8362007-09-25 19:18:04 -0700179 | NETIF_F_HIGHDMA
180 | NETIF_F_LLTX
Krishna Kumar0553c892011-04-14 06:07:04 +0000181 | NETIF_F_NETNS_LOCAL
Mahesh Bandewareed2a122011-05-04 15:30:11 +0000182 | NETIF_F_VLAN_CHALLENGED
183 | NETIF_F_LOOPBACK;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700184 dev->ethtool_ops = &loopback_ethtool_ops;
Stephen Hemminger3b04ddd2007-10-09 01:40:57 -0700185 dev->header_ops = &eth_header_ops;
Stephen Hemmingerc02373bf2008-11-19 21:46:18 -0800186 dev->netdev_ops = &loopback_ops;
187 dev->destructor = loopback_dev_free;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700188}
Daniel Lezcanode3cb742007-09-25 19:16:28 -0700189
Ralf Baechle22783642005-08-18 14:05:18 -0700190/* Setup and register the loopback device. */
Pavel Emelyanov46650792007-10-08 20:38:39 -0700191static __net_init int loopback_net_init(struct net *net)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192{
Daniel Lezcano854d8362007-09-25 19:18:04 -0700193 struct net_device *dev;
194 int err;
Herbert Xuaeed9e82007-07-30 16:37:19 -0700195
Daniel Lezcano854d8362007-09-25 19:18:04 -0700196 err = -ENOMEM;
197 dev = alloc_netdev(0, "lo", loopback_setup);
198 if (!dev)
199 goto out;
200
YOSHIFUJI Hideakic346dca2008-03-25 21:47:49 +0900201 dev_net_set(dev, net);
Daniel Lezcano854d8362007-09-25 19:18:04 -0700202 err = register_netdev(dev);
203 if (err)
204 goto out_free_netdev;
205
Pavel Emelyanov1fb94892012-08-08 21:53:36 +0000206 BUG_ON(dev->ifindex != LOOPBACK_IFINDEX);
Eric W. Biederman2774c7a2007-09-26 22:10:56 -0700207 net->loopback_dev = dev;
Pavel Emelyanov9d6dda322007-10-15 12:55:33 -0700208 return 0;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700209
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210
Daniel Lezcano854d8362007-09-25 19:18:04 -0700211out_free_netdev:
212 free_netdev(dev);
Pavel Emelyanov9d6dda322007-10-15 12:55:33 -0700213out:
Octavian Purdila09ad9bc2009-11-25 15:14:13 -0800214 if (net_eq(net, &init_net))
Pavel Emelyanov9d6dda322007-10-15 12:55:33 -0700215 panic("loopback: Failed to register netdevice: %d\n", err);
216 return err;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700217}
Adrian Bunk60903f22007-01-02 00:35:48 -0800218
Eric W. Biederman505d4f72008-11-07 22:54:20 -0800219/* Registered in net/core/dev.c */
220struct pernet_operations __net_initdata loopback_net_ops = {
Eric W. Biederman2774c7a2007-09-26 22:10:56 -0700221 .init = loopback_net_init,
Eric W. Biederman2774c7a2007-09-26 22:10:56 -0700222};