blob: c76283c2f84a4e7aa21b684770542e9b6202bffd [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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070042
Linus Torvalds1da177e2005-04-16 15:20:36 -070043#include <asm/uaccess.h>
44#include <asm/io.h>
45
46#include <linux/inet.h>
47#include <linux/netdevice.h>
48#include <linux/etherdevice.h>
49#include <linux/skbuff.h>
50#include <linux/ethtool.h>
51#include <net/sock.h>
52#include <net/checksum.h>
53#include <linux/if_ether.h> /* For the statistics structure. */
54#include <linux/if_arp.h> /* For ARPHRD_ETHER */
55#include <linux/ip.h>
56#include <linux/tcp.h>
57#include <linux/percpu.h>
Eric W. Biederman2774c7a2007-09-26 22:10:56 -070058#include <net/net_namespace.h>
Eric Dumazet5eaa0bd2010-06-22 12:44:11 +000059#include <linux/u64_stats_sync.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070060
Eric Dumazet5175c372006-10-18 20:51:57 -070061struct pcpu_lstats {
Eric Dumazet5eaa0bd2010-06-22 12:44:11 +000062 u64 packets;
63 u64 bytes;
64 struct u64_stats_sync syncp;
Eric Dumazet5175c372006-10-18 20:51:57 -070065};
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 */
Stephen Hemminger613573252009-08-31 19:50:58 +000071static netdev_tx_t loopback_xmit(struct sk_buff *skb,
72 struct net_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -070073{
Tejun Heo47d74272010-02-16 15:21:08 +000074 struct 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 Dumazet794ed392013-01-25 07:44:41 +000079 /* Before queueing this packet to netif_rx(),
80 * make sure dst is refcounted.
81 */
82 skb_dst_force(skb);
83
Eric Dumazet7eebb0b2009-04-17 22:03:10 +000084 skb->protocol = eth_type_trans(skb, dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -070085
Eric W. Biederman9e0db4b2007-09-27 17:09:39 -070086 /* it's OK to use per_cpu_ptr() because BHs are off */
Eric Dumazeta7855c72010-09-23 23:51:51 +000087 lb_stats = this_cpu_ptr(dev->lstats);
Linus Torvalds1da177e2005-04-16 15:20:36 -070088
Eric Dumazet7eebb0b2009-04-17 22:03:10 +000089 len = skb->len;
90 if (likely(netif_rx(skb) == NET_RX_SUCCESS)) {
Eric Dumazet5eaa0bd2010-06-22 12:44:11 +000091 u64_stats_update_begin(&lb_stats->syncp);
Eric Dumazet7eebb0b2009-04-17 22:03:10 +000092 lb_stats->bytes += len;
93 lb_stats->packets++;
Eric Dumazet5eaa0bd2010-06-22 12:44:11 +000094 u64_stats_update_end(&lb_stats->syncp);
Eric Dumazetcaf586e2010-09-30 21:06:55 +000095 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070096
Patrick McHardy6ed10652009-06-23 06:03:08 +000097 return NETDEV_TX_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -070098}
99
Eric Dumazet28172732010-07-07 14:58:56 -0700100static struct rtnl_link_stats64 *loopback_get_stats64(struct net_device *dev,
101 struct rtnl_link_stats64 *stats)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102{
Eric Dumazet6b10de32010-06-14 05:59:22 +0000103 u64 bytes = 0;
104 u64 packets = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105 int i;
106
KAMEZAWA Hiroyuki0fed4842006-03-28 01:56:37 -0800107 for_each_possible_cpu(i) {
Eric Dumazet5175c372006-10-18 20:51:57 -0700108 const struct pcpu_lstats *lb_stats;
Eric Dumazet5eaa0bd2010-06-22 12:44:11 +0000109 u64 tbytes, tpackets;
110 unsigned int start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111
Eric Dumazeta7855c72010-09-23 23:51:51 +0000112 lb_stats = per_cpu_ptr(dev->lstats, i);
Eric Dumazet5eaa0bd2010-06-22 12:44:11 +0000113 do {
Eric W. Biederman57a77442014-03-13 21:26:42 -0700114 start = u64_stats_fetch_begin_irq(&lb_stats->syncp);
Eric Dumazet5eaa0bd2010-06-22 12:44:11 +0000115 tbytes = lb_stats->bytes;
116 tpackets = lb_stats->packets;
Eric W. Biederman57a77442014-03-13 21:26:42 -0700117 } while (u64_stats_fetch_retry_irq(&lb_stats->syncp, start));
Eric Dumazet5eaa0bd2010-06-22 12:44:11 +0000118 bytes += tbytes;
119 packets += tpackets;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120 }
Eric Dumazet5175c372006-10-18 20:51:57 -0700121 stats->rx_packets = packets;
122 stats->tx_packets = packets;
Eric Dumazet7eebb0b2009-04-17 22:03:10 +0000123 stats->rx_bytes = bytes;
124 stats->tx_bytes = bytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125 return stats;
126}
127
Stephen Hemminger7fa6b062006-09-27 20:33:34 -0700128static u32 always_on(struct net_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129{
130 return 1;
131}
132
Jeff Garzik7282d492006-09-13 14:30:00 -0400133static const struct ethtool_ops loopback_ethtool_ops = {
Stephen Hemminger7fa6b062006-09-27 20:33:34 -0700134 .get_link = always_on,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135};
136
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -0700137static int loopback_dev_init(struct net_device *dev)
138{
WANG Cong1c213bd2014-02-13 11:46:28 -0800139 dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats);
Eric Dumazeta7855c72010-09-23 23:51:51 +0000140 if (!dev->lstats)
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -0700141 return -ENOMEM;
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -0700142 return 0;
143}
144
145static void loopback_dev_free(struct net_device *dev)
146{
Eric W. Biedermane05e9072013-09-16 16:52:41 -0700147 dev_net(dev)->loopback_dev = NULL;
Eric Dumazeta7855c72010-09-23 23:51:51 +0000148 free_percpu(dev->lstats);
Eric W. Biederman5f6d88b2007-09-26 22:08:12 -0700149 free_netdev(dev);
150}
151
Stephen Hemmingerc02373b2008-11-19 21:46:18 -0800152static const struct net_device_ops loopback_ops = {
153 .ndo_init = loopback_dev_init,
Stephen Hemminger00829822008-11-20 20:14:53 -0800154 .ndo_start_xmit= loopback_xmit,
Eric Dumazet6b10de32010-06-14 05:59:22 +0000155 .ndo_get_stats64 = loopback_get_stats64,
WANG Cong25f929f2014-02-11 17:21:26 -0800156 .ndo_set_mac_address = eth_mac_addr,
Stephen Hemmingerc02373b2008-11-19 21:46:18 -0800157};
158
Stephen Hemminger7fa6b062006-09-27 20:33:34 -0700159/*
Eric W. Biederman9e0db4b2007-09-27 17:09:39 -0700160 * The loopback device is special. There is only one instance
161 * per network namespace.
Stephen Hemminger7fa6b062006-09-27 20:33:34 -0700162 */
Daniel Lezcano854d8362007-09-25 19:18:04 -0700163static void loopback_setup(struct net_device *dev)
164{
Eric Dumazet0cf833a2012-09-23 22:28:59 +0000165 dev->mtu = 64 * 1024;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700166 dev->hard_header_len = ETH_HLEN; /* 14 */
167 dev->addr_len = ETH_ALEN; /* 6 */
168 dev->tx_queue_len = 0;
169 dev->type = ARPHRD_LOOPBACK; /* 0x0001*/
Daniel Lezcano854d8362007-09-25 19:18:04 -0700170 dev->flags = IFF_LOOPBACK;
WANG Cong25f929f2014-02-11 17:21:26 -0800171 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
Eric Dumazet02875872014-10-05 18:38:35 -0700172 netif_keep_dst(dev);
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 Borkmannb17c7062014-02-22 14:01:53 +0100179 | NETIF_F_SCTP_CSUM
Daniel Lezcano854d8362007-09-25 19:18:04 -0700180 | NETIF_F_HIGHDMA
181 | NETIF_F_LLTX
Krishna Kumar0553c892011-04-14 06:07:04 +0000182 | NETIF_F_NETNS_LOCAL
Mahesh Bandewareed2a122011-05-04 15:30:11 +0000183 | NETIF_F_VLAN_CHALLENGED
184 | NETIF_F_LOOPBACK;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700185 dev->ethtool_ops = &loopback_ethtool_ops;
Stephen Hemminger3b04ddd2007-10-09 01:40:57 -0700186 dev->header_ops = &eth_header_ops;
Stephen Hemmingerc02373b2008-11-19 21:46:18 -0800187 dev->netdev_ops = &loopback_ops;
188 dev->destructor = loopback_dev_free;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700189}
Daniel Lezcanode3cb742007-09-25 19:16:28 -0700190
Ralf Baechle22783642005-08-18 14:05:18 -0700191/* Setup and register the loopback device. */
Pavel Emelyanov46650792007-10-08 20:38:39 -0700192static __net_init int loopback_net_init(struct net *net)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193{
Daniel Lezcano854d8362007-09-25 19:18:04 -0700194 struct net_device *dev;
195 int err;
Herbert Xuaeed9e82007-07-30 16:37:19 -0700196
Daniel Lezcano854d8362007-09-25 19:18:04 -0700197 err = -ENOMEM;
Tom Gundersenc835a672014-07-14 16:37:24 +0200198 dev = alloc_netdev(0, "lo", NET_NAME_UNKNOWN, loopback_setup);
Daniel Lezcano854d8362007-09-25 19:18:04 -0700199 if (!dev)
200 goto out;
201
YOSHIFUJI Hideakic346dca2008-03-25 21:47:49 +0900202 dev_net_set(dev, net);
Daniel Lezcano854d8362007-09-25 19:18:04 -0700203 err = register_netdev(dev);
204 if (err)
205 goto out_free_netdev;
206
Pavel Emelyanov1fb94892012-08-08 21:53:36 +0000207 BUG_ON(dev->ifindex != LOOPBACK_IFINDEX);
Eric W. Biederman2774c7a2007-09-26 22:10:56 -0700208 net->loopback_dev = dev;
Pavel Emelyanov9d6dda322007-10-15 12:55:33 -0700209 return 0;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700210
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211
Daniel Lezcano854d8362007-09-25 19:18:04 -0700212out_free_netdev:
213 free_netdev(dev);
Pavel Emelyanov9d6dda322007-10-15 12:55:33 -0700214out:
Octavian Purdila09ad9bc2009-11-25 15:14:13 -0800215 if (net_eq(net, &init_net))
Pavel Emelyanov9d6dda322007-10-15 12:55:33 -0700216 panic("loopback: Failed to register netdevice: %d\n", err);
217 return err;
Daniel Lezcano854d8362007-09-25 19:18:04 -0700218}
Adrian Bunk60903f22007-01-02 00:35:48 -0800219
Eric W. Biederman505d4f72008-11-07 22:54:20 -0800220/* Registered in net/core/dev.c */
221struct pernet_operations __net_initdata loopback_net_ops = {
Eric W. Biederman2774c7a2007-09-26 22:10:56 -0700222 .init = loopback_net_init,
Eric W. Biederman2774c7a2007-09-26 22:10:56 -0700223};