Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 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 Juhl | 02c30a8 | 2005-05-05 16:16:16 -0700 | [diff] [blame] | 10 | * Authors: Ross Biro |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 11 | * 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. Biederman | 2774c7a | 2007-09-26 22:10:56 -0700 | [diff] [blame] | 60 | #include <net/net_namespace.h> |
Eric Dumazet | 5eaa0bd | 2010-06-22 12:44:11 +0000 | [diff] [blame] | 61 | #include <linux/u64_stats_sync.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 62 | |
Eric Dumazet | 5175c37 | 2006-10-18 20:51:57 -0700 | [diff] [blame] | 63 | struct pcpu_lstats { |
Eric Dumazet | 5eaa0bd | 2010-06-22 12:44:11 +0000 | [diff] [blame] | 64 | u64 packets; |
| 65 | u64 bytes; |
| 66 | struct u64_stats_sync syncp; |
Eric Dumazet | 5175c37 | 2006-10-18 20:51:57 -0700 | [diff] [blame] | 67 | }; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 68 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 69 | /* |
| 70 | * The higher levels take care of making this non-reentrant (it's |
| 71 | * called with bh's disabled). |
| 72 | */ |
Stephen Hemminger | 61357325 | 2009-08-31 19:50:58 +0000 | [diff] [blame] | 73 | static netdev_tx_t loopback_xmit(struct sk_buff *skb, |
| 74 | struct net_device *dev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 75 | { |
Tejun Heo | 47d7427 | 2010-02-16 15:21:08 +0000 | [diff] [blame] | 76 | struct pcpu_lstats *lb_stats; |
Eric Dumazet | 7eebb0b | 2009-04-17 22:03:10 +0000 | [diff] [blame] | 77 | int len; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 78 | |
| 79 | skb_orphan(skb); |
| 80 | |
Eric Dumazet | 7eebb0b | 2009-04-17 22:03:10 +0000 | [diff] [blame] | 81 | skb->protocol = eth_type_trans(skb, dev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 82 | |
Eric W. Biederman | 9e0db4b | 2007-09-27 17:09:39 -0700 | [diff] [blame] | 83 | /* it's OK to use per_cpu_ptr() because BHs are off */ |
Eric Dumazet | a7855c7 | 2010-09-23 23:51:51 +0000 | [diff] [blame] | 84 | lb_stats = this_cpu_ptr(dev->lstats); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 85 | |
Eric Dumazet | 7eebb0b | 2009-04-17 22:03:10 +0000 | [diff] [blame] | 86 | len = skb->len; |
| 87 | if (likely(netif_rx(skb) == NET_RX_SUCCESS)) { |
Eric Dumazet | 5eaa0bd | 2010-06-22 12:44:11 +0000 | [diff] [blame] | 88 | u64_stats_update_begin(&lb_stats->syncp); |
Eric Dumazet | 7eebb0b | 2009-04-17 22:03:10 +0000 | [diff] [blame] | 89 | lb_stats->bytes += len; |
| 90 | lb_stats->packets++; |
Eric Dumazet | 5eaa0bd | 2010-06-22 12:44:11 +0000 | [diff] [blame] | 91 | u64_stats_update_end(&lb_stats->syncp); |
Eric Dumazet | caf586e | 2010-09-30 21:06:55 +0000 | [diff] [blame] | 92 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 93 | |
Patrick McHardy | 6ed1065 | 2009-06-23 06:03:08 +0000 | [diff] [blame] | 94 | return NETDEV_TX_OK; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 95 | } |
| 96 | |
Eric Dumazet | 2817273 | 2010-07-07 14:58:56 -0700 | [diff] [blame] | 97 | static struct rtnl_link_stats64 *loopback_get_stats64(struct net_device *dev, |
| 98 | struct rtnl_link_stats64 *stats) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 99 | { |
Eric Dumazet | 6b10de3 | 2010-06-14 05:59:22 +0000 | [diff] [blame] | 100 | u64 bytes = 0; |
| 101 | u64 packets = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 102 | int i; |
| 103 | |
KAMEZAWA Hiroyuki | 0fed484 | 2006-03-28 01:56:37 -0800 | [diff] [blame] | 104 | for_each_possible_cpu(i) { |
Eric Dumazet | 5175c37 | 2006-10-18 20:51:57 -0700 | [diff] [blame] | 105 | const struct pcpu_lstats *lb_stats; |
Eric Dumazet | 5eaa0bd | 2010-06-22 12:44:11 +0000 | [diff] [blame] | 106 | u64 tbytes, tpackets; |
| 107 | unsigned int start; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 108 | |
Eric Dumazet | a7855c7 | 2010-09-23 23:51:51 +0000 | [diff] [blame] | 109 | lb_stats = per_cpu_ptr(dev->lstats, i); |
Eric Dumazet | 5eaa0bd | 2010-06-22 12:44:11 +0000 | [diff] [blame] | 110 | do { |
| 111 | start = u64_stats_fetch_begin(&lb_stats->syncp); |
| 112 | tbytes = lb_stats->bytes; |
| 113 | tpackets = lb_stats->packets; |
| 114 | } while (u64_stats_fetch_retry(&lb_stats->syncp, start)); |
Eric Dumazet | 5eaa0bd | 2010-06-22 12:44:11 +0000 | [diff] [blame] | 115 | bytes += tbytes; |
| 116 | packets += tpackets; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 117 | } |
Eric Dumazet | 5175c37 | 2006-10-18 20:51:57 -0700 | [diff] [blame] | 118 | stats->rx_packets = packets; |
| 119 | stats->tx_packets = packets; |
Eric Dumazet | 7eebb0b | 2009-04-17 22:03:10 +0000 | [diff] [blame] | 120 | stats->rx_bytes = bytes; |
| 121 | stats->tx_bytes = bytes; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 122 | return stats; |
| 123 | } |
| 124 | |
Stephen Hemminger | 7fa6b06 | 2006-09-27 20:33:34 -0700 | [diff] [blame] | 125 | static u32 always_on(struct net_device *dev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 126 | { |
| 127 | return 1; |
| 128 | } |
| 129 | |
Jeff Garzik | 7282d49 | 2006-09-13 14:30:00 -0400 | [diff] [blame] | 130 | static const struct ethtool_ops loopback_ethtool_ops = { |
Stephen Hemminger | 7fa6b06 | 2006-09-27 20:33:34 -0700 | [diff] [blame] | 131 | .get_link = always_on, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 132 | }; |
| 133 | |
Eric W. Biederman | 5f6d88b | 2007-09-26 22:08:12 -0700 | [diff] [blame] | 134 | static int loopback_dev_init(struct net_device *dev) |
| 135 | { |
Eric Dumazet | a7855c7 | 2010-09-23 23:51:51 +0000 | [diff] [blame] | 136 | dev->lstats = alloc_percpu(struct pcpu_lstats); |
| 137 | if (!dev->lstats) |
Eric W. Biederman | 5f6d88b | 2007-09-26 22:08:12 -0700 | [diff] [blame] | 138 | return -ENOMEM; |
| 139 | |
Eric W. Biederman | 5f6d88b | 2007-09-26 22:08:12 -0700 | [diff] [blame] | 140 | return 0; |
| 141 | } |
| 142 | |
| 143 | static void loopback_dev_free(struct net_device *dev) |
| 144 | { |
Eric Dumazet | a7855c7 | 2010-09-23 23:51:51 +0000 | [diff] [blame] | 145 | free_percpu(dev->lstats); |
Eric W. Biederman | 5f6d88b | 2007-09-26 22:08:12 -0700 | [diff] [blame] | 146 | free_netdev(dev); |
| 147 | } |
| 148 | |
Stephen Hemminger | c02373b | 2008-11-19 21:46:18 -0800 | [diff] [blame] | 149 | static const struct net_device_ops loopback_ops = { |
| 150 | .ndo_init = loopback_dev_init, |
Stephen Hemminger | 0082982 | 2008-11-20 20:14:53 -0800 | [diff] [blame] | 151 | .ndo_start_xmit= loopback_xmit, |
Eric Dumazet | 6b10de3 | 2010-06-14 05:59:22 +0000 | [diff] [blame] | 152 | .ndo_get_stats64 = loopback_get_stats64, |
Stephen Hemminger | c02373b | 2008-11-19 21:46:18 -0800 | [diff] [blame] | 153 | }; |
| 154 | |
Stephen Hemminger | 7fa6b06 | 2006-09-27 20:33:34 -0700 | [diff] [blame] | 155 | /* |
Eric W. Biederman | 9e0db4b | 2007-09-27 17:09:39 -0700 | [diff] [blame] | 156 | * The loopback device is special. There is only one instance |
| 157 | * per network namespace. |
Stephen Hemminger | 7fa6b06 | 2006-09-27 20:33:34 -0700 | [diff] [blame] | 158 | */ |
Daniel Lezcano | 854d836 | 2007-09-25 19:18:04 -0700 | [diff] [blame] | 159 | static void loopback_setup(struct net_device *dev) |
| 160 | { |
Daniel Lezcano | 854d836 | 2007-09-25 19:18:04 -0700 | [diff] [blame] | 161 | dev->mtu = (16 * 1024) + 20 + 20 + 12; |
Daniel Lezcano | 854d836 | 2007-09-25 19:18:04 -0700 | [diff] [blame] | 162 | dev->hard_header_len = ETH_HLEN; /* 14 */ |
| 163 | dev->addr_len = ETH_ALEN; /* 6 */ |
| 164 | dev->tx_queue_len = 0; |
| 165 | dev->type = ARPHRD_LOOPBACK; /* 0x0001*/ |
Daniel Lezcano | 854d836 | 2007-09-25 19:18:04 -0700 | [diff] [blame] | 166 | dev->flags = IFF_LOOPBACK; |
Eric Dumazet | 93f154b | 2009-05-18 22:19:19 -0700 | [diff] [blame] | 167 | dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; |
Michał Mirosław | cf0bdef | 2011-02-15 16:59:18 +0000 | [diff] [blame] | 168 | dev->hw_features = NETIF_F_ALL_TSO | NETIF_F_UFO; |
Daniel Lezcano | 854d836 | 2007-09-25 19:18:04 -0700 | [diff] [blame] | 169 | dev->features = NETIF_F_SG | NETIF_F_FRAGLIST |
Michał Mirosław | cf0bdef | 2011-02-15 16:59:18 +0000 | [diff] [blame] | 170 | | NETIF_F_ALL_TSO |
| 171 | | NETIF_F_UFO |
Michał Mirosław | 34324dc | 2011-11-15 15:29:55 +0000 | [diff] [blame] | 172 | | NETIF_F_HW_CSUM |
Michał Mirosław | cf0bdef | 2011-02-15 16:59:18 +0000 | [diff] [blame] | 173 | | NETIF_F_RXCSUM |
Daniel Lezcano | 854d836 | 2007-09-25 19:18:04 -0700 | [diff] [blame] | 174 | | NETIF_F_HIGHDMA |
| 175 | | NETIF_F_LLTX |
Krishna Kumar | 0553c89 | 2011-04-14 06:07:04 +0000 | [diff] [blame] | 176 | | NETIF_F_NETNS_LOCAL |
Mahesh Bandewar | eed2a12 | 2011-05-04 15:30:11 +0000 | [diff] [blame] | 177 | | NETIF_F_VLAN_CHALLENGED |
| 178 | | NETIF_F_LOOPBACK; |
Daniel Lezcano | 854d836 | 2007-09-25 19:18:04 -0700 | [diff] [blame] | 179 | dev->ethtool_ops = &loopback_ethtool_ops; |
Stephen Hemminger | 3b04ddd | 2007-10-09 01:40:57 -0700 | [diff] [blame] | 180 | dev->header_ops = ð_header_ops; |
Stephen Hemminger | c02373b | 2008-11-19 21:46:18 -0800 | [diff] [blame] | 181 | dev->netdev_ops = &loopback_ops; |
| 182 | dev->destructor = loopback_dev_free; |
Daniel Lezcano | 854d836 | 2007-09-25 19:18:04 -0700 | [diff] [blame] | 183 | } |
Daniel Lezcano | de3cb74 | 2007-09-25 19:16:28 -0700 | [diff] [blame] | 184 | |
Ralf Baechle | 2278364 | 2005-08-18 14:05:18 -0700 | [diff] [blame] | 185 | /* Setup and register the loopback device. */ |
Pavel Emelyanov | 4665079 | 2007-10-08 20:38:39 -0700 | [diff] [blame] | 186 | static __net_init int loopback_net_init(struct net *net) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 187 | { |
Daniel Lezcano | 854d836 | 2007-09-25 19:18:04 -0700 | [diff] [blame] | 188 | struct net_device *dev; |
| 189 | int err; |
Herbert Xu | aeed9e8 | 2007-07-30 16:37:19 -0700 | [diff] [blame] | 190 | |
Daniel Lezcano | 854d836 | 2007-09-25 19:18:04 -0700 | [diff] [blame] | 191 | err = -ENOMEM; |
| 192 | dev = alloc_netdev(0, "lo", loopback_setup); |
| 193 | if (!dev) |
| 194 | goto out; |
| 195 | |
YOSHIFUJI Hideaki | c346dca | 2008-03-25 21:47:49 +0900 | [diff] [blame] | 196 | dev_net_set(dev, net); |
Daniel Lezcano | 854d836 | 2007-09-25 19:18:04 -0700 | [diff] [blame] | 197 | err = register_netdev(dev); |
| 198 | if (err) |
| 199 | goto out_free_netdev; |
| 200 | |
Eric W. Biederman | 2774c7a | 2007-09-26 22:10:56 -0700 | [diff] [blame] | 201 | net->loopback_dev = dev; |
Pavel Emelyanov | 9d6dda3 | 2007-10-15 12:55:33 -0700 | [diff] [blame] | 202 | return 0; |
Daniel Lezcano | 854d836 | 2007-09-25 19:18:04 -0700 | [diff] [blame] | 203 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 204 | |
Daniel Lezcano | 854d836 | 2007-09-25 19:18:04 -0700 | [diff] [blame] | 205 | out_free_netdev: |
| 206 | free_netdev(dev); |
Pavel Emelyanov | 9d6dda3 | 2007-10-15 12:55:33 -0700 | [diff] [blame] | 207 | out: |
Octavian Purdila | 09ad9bc | 2009-11-25 15:14:13 -0800 | [diff] [blame] | 208 | if (net_eq(net, &init_net)) |
Pavel Emelyanov | 9d6dda3 | 2007-10-15 12:55:33 -0700 | [diff] [blame] | 209 | panic("loopback: Failed to register netdevice: %d\n", err); |
| 210 | return err; |
Daniel Lezcano | 854d836 | 2007-09-25 19:18:04 -0700 | [diff] [blame] | 211 | } |
Adrian Bunk | 60903f2 | 2007-01-02 00:35:48 -0800 | [diff] [blame] | 212 | |
Eric W. Biederman | 505d4f7 | 2008-11-07 22:54:20 -0800 | [diff] [blame] | 213 | /* Registered in net/core/dev.c */ |
| 214 | struct pernet_operations __net_initdata loopback_net_ops = { |
Eric W. Biederman | 2774c7a | 2007-09-26 22:10:56 -0700 | [diff] [blame] | 215 | .init = loopback_net_init, |
Eric W. Biederman | 2774c7a | 2007-09-26 22:10:56 -0700 | [diff] [blame] | 216 | }; |