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> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 61 | |
Eric Dumazet | 5175c37 | 2006-10-18 20:51:57 -0700 | [diff] [blame] | 62 | struct pcpu_lstats { |
| 63 | unsigned long packets; |
| 64 | unsigned long bytes; |
| 65 | }; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 66 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 67 | /* |
| 68 | * The higher levels take care of making this non-reentrant (it's |
| 69 | * called with bh's disabled). |
| 70 | */ |
| 71 | static int loopback_xmit(struct sk_buff *skb, struct net_device *dev) |
| 72 | { |
Eric W. Biederman | 5f6d88b | 2007-09-26 22:08:12 -0700 | [diff] [blame] | 73 | struct pcpu_lstats *pcpu_lstats, *lb_stats; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 74 | |
| 75 | skb_orphan(skb); |
| 76 | |
Chuck Ebbert | 0e920bf | 2005-07-02 21:28:23 -0400 | [diff] [blame] | 77 | skb->protocol = eth_type_trans(skb,dev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 78 | |
Chuck Ebbert | d2ae1d2 | 2005-07-02 21:28:21 -0400 | [diff] [blame] | 79 | #ifdef LOOPBACK_TSO |
Herbert Xu | 89114af | 2006-07-08 13:34:32 -0700 | [diff] [blame] | 80 | if (skb_is_gso(skb)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 81 | BUG_ON(skb->protocol != htons(ETH_P_IP)); |
Arnaldo Carvalho de Melo | eddc9ec | 2007-04-20 22:47:35 -0700 | [diff] [blame] | 82 | BUG_ON(ip_hdr(skb)->protocol != IPPROTO_TCP); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 83 | |
| 84 | emulate_large_send_offload(skb); |
| 85 | return 0; |
| 86 | } |
Chuck Ebbert | d2ae1d2 | 2005-07-02 21:28:21 -0400 | [diff] [blame] | 87 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 88 | dev->last_rx = jiffies; |
| 89 | |
Eric W. Biederman | 9e0db4b | 2007-09-27 17:09:39 -0700 | [diff] [blame] | 90 | /* it's OK to use per_cpu_ptr() because BHs are off */ |
David S. Miller | e3c50d5 | 2008-07-15 02:58:39 -0700 | [diff] [blame] | 91 | pcpu_lstats = dev->ml_priv; |
Eric W. Biederman | 5f6d88b | 2007-09-26 22:08:12 -0700 | [diff] [blame] | 92 | lb_stats = per_cpu_ptr(pcpu_lstats, smp_processor_id()); |
Eric Dumazet | 5175c37 | 2006-10-18 20:51:57 -0700 | [diff] [blame] | 93 | lb_stats->bytes += skb->len; |
| 94 | lb_stats->packets++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 95 | |
| 96 | netif_rx(skb); |
| 97 | |
Eric Dumazet | 58f5397 | 2006-10-20 00:32:41 -0700 | [diff] [blame] | 98 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 99 | } |
| 100 | |
| 101 | static struct net_device_stats *get_stats(struct net_device *dev) |
| 102 | { |
Eric W. Biederman | 5f6d88b | 2007-09-26 22:08:12 -0700 | [diff] [blame] | 103 | const struct pcpu_lstats *pcpu_lstats; |
Eric Dumazet | 3303680 | 2007-04-10 13:25:40 -0700 | [diff] [blame] | 104 | struct net_device_stats *stats = &dev->stats; |
Eric Dumazet | 5175c37 | 2006-10-18 20:51:57 -0700 | [diff] [blame] | 105 | unsigned long bytes = 0; |
| 106 | unsigned long packets = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 107 | int i; |
| 108 | |
David S. Miller | e3c50d5 | 2008-07-15 02:58:39 -0700 | [diff] [blame] | 109 | pcpu_lstats = dev->ml_priv; |
KAMEZAWA Hiroyuki | 0fed484 | 2006-03-28 01:56:37 -0800 | [diff] [blame] | 110 | for_each_possible_cpu(i) { |
Eric Dumazet | 5175c37 | 2006-10-18 20:51:57 -0700 | [diff] [blame] | 111 | const struct pcpu_lstats *lb_stats; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 112 | |
Eric W. Biederman | 5f6d88b | 2007-09-26 22:08:12 -0700 | [diff] [blame] | 113 | lb_stats = per_cpu_ptr(pcpu_lstats, i); |
Eric Dumazet | 5175c37 | 2006-10-18 20:51:57 -0700 | [diff] [blame] | 114 | bytes += lb_stats->bytes; |
| 115 | packets += lb_stats->packets; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 116 | } |
Eric Dumazet | 5175c37 | 2006-10-18 20:51:57 -0700 | [diff] [blame] | 117 | stats->rx_packets = packets; |
| 118 | stats->tx_packets = packets; |
| 119 | stats->rx_bytes = bytes; |
| 120 | stats->tx_bytes = bytes; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 121 | return stats; |
| 122 | } |
| 123 | |
Stephen Hemminger | 7fa6b06 | 2006-09-27 20:33:34 -0700 | [diff] [blame] | 124 | static u32 always_on(struct net_device *dev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 125 | { |
| 126 | return 1; |
| 127 | } |
| 128 | |
Jeff Garzik | 7282d49 | 2006-09-13 14:30:00 -0400 | [diff] [blame] | 129 | static const struct ethtool_ops loopback_ethtool_ops = { |
Stephen Hemminger | 7fa6b06 | 2006-09-27 20:33:34 -0700 | [diff] [blame] | 130 | .get_link = always_on, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 131 | .set_tso = ethtool_op_set_tso, |
Stephen Hemminger | 7fa6b06 | 2006-09-27 20:33:34 -0700 | [diff] [blame] | 132 | .get_tx_csum = always_on, |
| 133 | .get_sg = always_on, |
| 134 | .get_rx_csum = always_on, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 135 | }; |
| 136 | |
Eric W. Biederman | 5f6d88b | 2007-09-26 22:08:12 -0700 | [diff] [blame] | 137 | static int loopback_dev_init(struct net_device *dev) |
| 138 | { |
| 139 | struct pcpu_lstats *lstats; |
| 140 | |
| 141 | lstats = alloc_percpu(struct pcpu_lstats); |
| 142 | if (!lstats) |
| 143 | return -ENOMEM; |
| 144 | |
David S. Miller | e3c50d5 | 2008-07-15 02:58:39 -0700 | [diff] [blame] | 145 | dev->ml_priv = lstats; |
Eric W. Biederman | 5f6d88b | 2007-09-26 22:08:12 -0700 | [diff] [blame] | 146 | return 0; |
| 147 | } |
| 148 | |
| 149 | static void loopback_dev_free(struct net_device *dev) |
| 150 | { |
David S. Miller | e3c50d5 | 2008-07-15 02:58:39 -0700 | [diff] [blame] | 151 | struct pcpu_lstats *lstats = dev->ml_priv; |
Eric W. Biederman | 5f6d88b | 2007-09-26 22:08:12 -0700 | [diff] [blame] | 152 | |
| 153 | free_percpu(lstats); |
| 154 | free_netdev(dev); |
| 155 | } |
| 156 | |
Stephen Hemminger | 7fa6b06 | 2006-09-27 20:33:34 -0700 | [diff] [blame] | 157 | /* |
Eric W. Biederman | 9e0db4b | 2007-09-27 17:09:39 -0700 | [diff] [blame] | 158 | * The loopback device is special. There is only one instance |
| 159 | * per network namespace. |
Stephen Hemminger | 7fa6b06 | 2006-09-27 20:33:34 -0700 | [diff] [blame] | 160 | */ |
Daniel Lezcano | 854d836 | 2007-09-25 19:18:04 -0700 | [diff] [blame] | 161 | static void loopback_setup(struct net_device *dev) |
| 162 | { |
| 163 | dev->get_stats = &get_stats; |
| 164 | dev->mtu = (16 * 1024) + 20 + 20 + 12; |
| 165 | dev->hard_start_xmit = loopback_xmit; |
Daniel Lezcano | 854d836 | 2007-09-25 19:18:04 -0700 | [diff] [blame] | 166 | 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 Lezcano | 854d836 | 2007-09-25 19:18:04 -0700 | [diff] [blame] | 170 | dev->flags = IFF_LOOPBACK; |
| 171 | dev->features = NETIF_F_SG | NETIF_F_FRAGLIST |
Daniel Lezcano | 854d836 | 2007-09-25 19:18:04 -0700 | [diff] [blame] | 172 | | NETIF_F_TSO |
Daniel Lezcano | 854d836 | 2007-09-25 19:18:04 -0700 | [diff] [blame] | 173 | | NETIF_F_NO_CSUM |
| 174 | | NETIF_F_HIGHDMA |
| 175 | | NETIF_F_LLTX |
Emil Medve | 2d2c54e | 2007-12-27 08:17:22 -0600 | [diff] [blame] | 176 | | NETIF_F_NETNS_LOCAL; |
Daniel Lezcano | 854d836 | 2007-09-25 19:18:04 -0700 | [diff] [blame] | 177 | dev->ethtool_ops = &loopback_ethtool_ops; |
Stephen Hemminger | 3b04ddd | 2007-10-09 01:40:57 -0700 | [diff] [blame] | 178 | dev->header_ops = ð_header_ops; |
Eric W. Biederman | 5f6d88b | 2007-09-26 22:08:12 -0700 | [diff] [blame] | 179 | dev->init = loopback_dev_init; |
| 180 | dev->destructor = loopback_dev_free; |
Daniel Lezcano | 854d836 | 2007-09-25 19:18:04 -0700 | [diff] [blame] | 181 | } |
Daniel Lezcano | de3cb74 | 2007-09-25 19:16:28 -0700 | [diff] [blame] | 182 | |
Ralf Baechle | 2278364 | 2005-08-18 14:05:18 -0700 | [diff] [blame] | 183 | /* Setup and register the loopback device. */ |
Pavel Emelyanov | 4665079 | 2007-10-08 20:38:39 -0700 | [diff] [blame] | 184 | static __net_init int loopback_net_init(struct net *net) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 185 | { |
Daniel Lezcano | 854d836 | 2007-09-25 19:18:04 -0700 | [diff] [blame] | 186 | struct net_device *dev; |
| 187 | int err; |
Herbert Xu | aeed9e8 | 2007-07-30 16:37:19 -0700 | [diff] [blame] | 188 | |
Daniel Lezcano | 854d836 | 2007-09-25 19:18:04 -0700 | [diff] [blame] | 189 | err = -ENOMEM; |
| 190 | dev = alloc_netdev(0, "lo", loopback_setup); |
| 191 | if (!dev) |
| 192 | goto out; |
| 193 | |
YOSHIFUJI Hideaki | c346dca | 2008-03-25 21:47:49 +0900 | [diff] [blame] | 194 | dev_net_set(dev, net); |
Daniel Lezcano | 854d836 | 2007-09-25 19:18:04 -0700 | [diff] [blame] | 195 | err = register_netdev(dev); |
| 196 | if (err) |
| 197 | goto out_free_netdev; |
| 198 | |
Eric W. Biederman | 2774c7a | 2007-09-26 22:10:56 -0700 | [diff] [blame] | 199 | net->loopback_dev = dev; |
Pavel Emelyanov | 9d6dda32 | 2007-10-15 12:55:33 -0700 | [diff] [blame] | 200 | return 0; |
Daniel Lezcano | 854d836 | 2007-09-25 19:18:04 -0700 | [diff] [blame] | 201 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 202 | |
Daniel Lezcano | 854d836 | 2007-09-25 19:18:04 -0700 | [diff] [blame] | 203 | out_free_netdev: |
| 204 | free_netdev(dev); |
Pavel Emelyanov | 9d6dda32 | 2007-10-15 12:55:33 -0700 | [diff] [blame] | 205 | out: |
| 206 | if (net == &init_net) |
| 207 | panic("loopback: Failed to register netdevice: %d\n", err); |
| 208 | return err; |
Daniel Lezcano | 854d836 | 2007-09-25 19:18:04 -0700 | [diff] [blame] | 209 | } |
Adrian Bunk | 60903f2 | 2007-01-02 00:35:48 -0800 | [diff] [blame] | 210 | |
Pavel Emelyanov | 4665079 | 2007-10-08 20:38:39 -0700 | [diff] [blame] | 211 | static __net_exit void loopback_net_exit(struct net *net) |
Eric W. Biederman | 2774c7a | 2007-09-26 22:10:56 -0700 | [diff] [blame] | 212 | { |
| 213 | struct net_device *dev = net->loopback_dev; |
Daniel Lezcano | 854d836 | 2007-09-25 19:18:04 -0700 | [diff] [blame] | 214 | |
Eric W. Biederman | 2774c7a | 2007-09-26 22:10:56 -0700 | [diff] [blame] | 215 | unregister_netdev(dev); |
| 216 | } |
| 217 | |
Denis V. Lunev | 022cbae | 2007-11-13 03:23:50 -0800 | [diff] [blame] | 218 | static struct pernet_operations __net_initdata loopback_net_ops = { |
Eric W. Biederman | 2774c7a | 2007-09-26 22:10:56 -0700 | [diff] [blame] | 219 | .init = loopback_net_init, |
| 220 | .exit = loopback_net_exit, |
| 221 | }; |
| 222 | |
| 223 | static int __init loopback_init(void) |
| 224 | { |
| 225 | return register_pernet_device(&loopback_net_ops); |
| 226 | } |
| 227 | |
Denis V. Lunev | 070ac3a | 2007-09-27 12:04:19 -0700 | [diff] [blame] | 228 | /* Loopback is special. It should be initialized before any other network |
| 229 | * device and network subsystem. |
| 230 | */ |
Eric W. Biederman | 2774c7a | 2007-09-26 22:10:56 -0700 | [diff] [blame] | 231 | fs_initcall(loopback_init); |