Commit | Line | Data |
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1da177e4 LT |
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 | * | |
02c30a84 | 10 | * Authors: Ross Biro |
1da177e4 LT |
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> | |
2774c7ab | 60 | #include <net/net_namespace.h> |
1da177e4 | 61 | |
5175c378 ED |
62 | struct pcpu_lstats { |
63 | unsigned long packets; | |
64 | unsigned long bytes; | |
65 | }; | |
1da177e4 | 66 | |
1da177e4 LT |
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 | { | |
5f6d88b9 | 73 | struct pcpu_lstats *pcpu_lstats, *lb_stats; |
1da177e4 LT |
74 | |
75 | skb_orphan(skb); | |
76 | ||
0e920bfb | 77 | skb->protocol = eth_type_trans(skb,dev); |
1da177e4 | 78 | |
d2ae1d2f | 79 | #ifdef LOOPBACK_TSO |
89114afd | 80 | if (skb_is_gso(skb)) { |
1da177e4 | 81 | BUG_ON(skb->protocol != htons(ETH_P_IP)); |
eddc9ec5 | 82 | BUG_ON(ip_hdr(skb)->protocol != IPPROTO_TCP); |
1da177e4 LT |
83 | |
84 | emulate_large_send_offload(skb); | |
85 | return 0; | |
86 | } | |
d2ae1d2f | 87 | #endif |
1da177e4 LT |
88 | dev->last_rx = jiffies; |
89 | ||
9e0db4b1 | 90 | /* it's OK to use per_cpu_ptr() because BHs are off */ |
e3c50d5d | 91 | pcpu_lstats = dev->ml_priv; |
5f6d88b9 | 92 | lb_stats = per_cpu_ptr(pcpu_lstats, smp_processor_id()); |
5175c378 ED |
93 | lb_stats->bytes += skb->len; |
94 | lb_stats->packets++; | |
1da177e4 LT |
95 | |
96 | netif_rx(skb); | |
97 | ||
58f53974 | 98 | return 0; |
1da177e4 LT |
99 | } |
100 | ||
101 | static struct net_device_stats *get_stats(struct net_device *dev) | |
102 | { | |
5f6d88b9 | 103 | const struct pcpu_lstats *pcpu_lstats; |
33036807 | 104 | struct net_device_stats *stats = &dev->stats; |
5175c378 ED |
105 | unsigned long bytes = 0; |
106 | unsigned long packets = 0; | |
1da177e4 LT |
107 | int i; |
108 | ||
e3c50d5d | 109 | pcpu_lstats = dev->ml_priv; |
0fed4846 | 110 | for_each_possible_cpu(i) { |
5175c378 | 111 | const struct pcpu_lstats *lb_stats; |
1da177e4 | 112 | |
5f6d88b9 | 113 | lb_stats = per_cpu_ptr(pcpu_lstats, i); |
5175c378 ED |
114 | bytes += lb_stats->bytes; |
115 | packets += lb_stats->packets; | |
1da177e4 | 116 | } |
5175c378 ED |
117 | stats->rx_packets = packets; |
118 | stats->tx_packets = packets; | |
119 | stats->rx_bytes = bytes; | |
120 | stats->tx_bytes = bytes; | |
1da177e4 LT |
121 | return stats; |
122 | } | |
123 | ||
7fa6b066 | 124 | static u32 always_on(struct net_device *dev) |
1da177e4 LT |
125 | { |
126 | return 1; | |
127 | } | |
128 | ||
7282d491 | 129 | static const struct ethtool_ops loopback_ethtool_ops = { |
7fa6b066 | 130 | .get_link = always_on, |
1da177e4 | 131 | .set_tso = ethtool_op_set_tso, |
7fa6b066 SH |
132 | .get_tx_csum = always_on, |
133 | .get_sg = always_on, | |
134 | .get_rx_csum = always_on, | |
1da177e4 LT |
135 | }; |
136 | ||
5f6d88b9 EB |
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 | ||
e3c50d5d | 145 | dev->ml_priv = lstats; |
5f6d88b9 EB |
146 | return 0; |
147 | } | |
148 | ||
149 | static void loopback_dev_free(struct net_device *dev) | |
150 | { | |
e3c50d5d | 151 | struct pcpu_lstats *lstats = dev->ml_priv; |
5f6d88b9 EB |
152 | |
153 | free_percpu(lstats); | |
154 | free_netdev(dev); | |
155 | } | |
156 | ||
7fa6b066 | 157 | /* |
9e0db4b1 EB |
158 | * The loopback device is special. There is only one instance |
159 | * per network namespace. | |
7fa6b066 | 160 | */ |
854d8363 DL |
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; | |
854d8363 DL |
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*/ | |
854d8363 DL |
170 | dev->flags = IFF_LOOPBACK; |
171 | dev->features = NETIF_F_SG | NETIF_F_FRAGLIST | |
854d8363 | 172 | | NETIF_F_TSO |
854d8363 DL |
173 | | NETIF_F_NO_CSUM |
174 | | NETIF_F_HIGHDMA | |
175 | | NETIF_F_LLTX | |
2d2c54e3 | 176 | | NETIF_F_NETNS_LOCAL; |
854d8363 | 177 | dev->ethtool_ops = &loopback_ethtool_ops; |
3b04ddde | 178 | dev->header_ops = ð_header_ops; |
5f6d88b9 EB |
179 | dev->init = loopback_dev_init; |
180 | dev->destructor = loopback_dev_free; | |
854d8363 | 181 | } |
de3cb747 | 182 | |
22783649 | 183 | /* Setup and register the loopback device. */ |
4665079c | 184 | static __net_init int loopback_net_init(struct net *net) |
1da177e4 | 185 | { |
854d8363 DL |
186 | struct net_device *dev; |
187 | int err; | |
188 | ||
189 | err = -ENOMEM; | |
190 | dev = alloc_netdev(0, "lo", loopback_setup); | |
191 | if (!dev) | |
192 | goto out; | |
aeed9e82 | 193 | |
c346dca1 | 194 | dev_net_set(dev, net); |
854d8363 | 195 | err = register_netdev(dev); |
aeed9e82 | 196 | if (err) |
854d8363 | 197 | goto out_free_netdev; |
aeed9e82 | 198 | |
2774c7ab | 199 | net->loopback_dev = dev; |
9d6dda32 | 200 | return 0; |
854d8363 | 201 | |
1da177e4 | 202 | |
854d8363 DL |
203 | out_free_netdev: |
204 | free_netdev(dev); | |
9d6dda32 PE |
205 | out: |
206 | if (net == &init_net) | |
207 | panic("loopback: Failed to register netdevice: %d\n", err); | |
208 | return err; | |
854d8363 DL |
209 | } |
210 | ||
4665079c | 211 | static __net_exit void loopback_net_exit(struct net *net) |
2774c7ab EB |
212 | { |
213 | struct net_device *dev = net->loopback_dev; | |
214 | ||
215 | unregister_netdev(dev); | |
216 | } | |
217 | ||
022cbae6 | 218 | static struct pernet_operations __net_initdata loopback_net_ops = { |
2774c7ab EB |
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 | } | |
60903f2c | 227 | |
070ac3a2 DL |
228 | /* Loopback is special. It should be initialized before any other network |
229 | * device and network subsystem. | |
230 | */ | |
2774c7ab | 231 | fs_initcall(loopback_init); |