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> |
5eaa0bd8 | 61 | #include <linux/u64_stats_sync.h> |
1da177e4 | 62 | |
5175c378 | 63 | struct pcpu_lstats { |
5eaa0bd8 ED |
64 | u64 packets; |
65 | u64 bytes; | |
66 | struct u64_stats_sync syncp; | |
5175c378 | 67 | }; |
1da177e4 | 68 | |
1da177e4 LT |
69 | /* |
70 | * The higher levels take care of making this non-reentrant (it's | |
71 | * called with bh's disabled). | |
72 | */ | |
61357325 SH |
73 | static netdev_tx_t loopback_xmit(struct sk_buff *skb, |
74 | struct net_device *dev) | |
1da177e4 | 75 | { |
47d74275 | 76 | struct pcpu_lstats *lb_stats; |
7eebb0b2 | 77 | int len; |
1da177e4 LT |
78 | |
79 | skb_orphan(skb); | |
80 | ||
7eebb0b2 | 81 | skb->protocol = eth_type_trans(skb, dev); |
1da177e4 | 82 | |
9e0db4b1 | 83 | /* it's OK to use per_cpu_ptr() because BHs are off */ |
a7855c78 | 84 | lb_stats = this_cpu_ptr(dev->lstats); |
1da177e4 | 85 | |
7eebb0b2 ED |
86 | len = skb->len; |
87 | if (likely(netif_rx(skb) == NET_RX_SUCCESS)) { | |
5eaa0bd8 | 88 | u64_stats_update_begin(&lb_stats->syncp); |
7eebb0b2 ED |
89 | lb_stats->bytes += len; |
90 | lb_stats->packets++; | |
5eaa0bd8 | 91 | u64_stats_update_end(&lb_stats->syncp); |
caf586e5 | 92 | } |
1da177e4 | 93 | |
6ed10654 | 94 | return NETDEV_TX_OK; |
1da177e4 LT |
95 | } |
96 | ||
28172739 ED |
97 | static struct rtnl_link_stats64 *loopback_get_stats64(struct net_device *dev, |
98 | struct rtnl_link_stats64 *stats) | |
1da177e4 | 99 | { |
6b10de38 ED |
100 | u64 bytes = 0; |
101 | u64 packets = 0; | |
1da177e4 LT |
102 | int i; |
103 | ||
0fed4846 | 104 | for_each_possible_cpu(i) { |
5175c378 | 105 | const struct pcpu_lstats *lb_stats; |
5eaa0bd8 ED |
106 | u64 tbytes, tpackets; |
107 | unsigned int start; | |
1da177e4 | 108 | |
a7855c78 | 109 | lb_stats = per_cpu_ptr(dev->lstats, i); |
5eaa0bd8 ED |
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)); | |
5eaa0bd8 ED |
115 | bytes += tbytes; |
116 | packets += tpackets; | |
1da177e4 | 117 | } |
5175c378 ED |
118 | stats->rx_packets = packets; |
119 | stats->tx_packets = packets; | |
7eebb0b2 ED |
120 | stats->rx_bytes = bytes; |
121 | stats->tx_bytes = bytes; | |
1da177e4 LT |
122 | return stats; |
123 | } | |
124 | ||
7fa6b066 | 125 | static u32 always_on(struct net_device *dev) |
1da177e4 LT |
126 | { |
127 | return 1; | |
128 | } | |
129 | ||
7282d491 | 130 | static const struct ethtool_ops loopback_ethtool_ops = { |
7fa6b066 | 131 | .get_link = always_on, |
1da177e4 LT |
132 | }; |
133 | ||
5f6d88b9 EB |
134 | static int loopback_dev_init(struct net_device *dev) |
135 | { | |
a7855c78 ED |
136 | dev->lstats = alloc_percpu(struct pcpu_lstats); |
137 | if (!dev->lstats) | |
5f6d88b9 EB |
138 | return -ENOMEM; |
139 | ||
5f6d88b9 EB |
140 | return 0; |
141 | } | |
142 | ||
143 | static void loopback_dev_free(struct net_device *dev) | |
144 | { | |
a7855c78 | 145 | free_percpu(dev->lstats); |
5f6d88b9 EB |
146 | free_netdev(dev); |
147 | } | |
148 | ||
c02373bf SH |
149 | static const struct net_device_ops loopback_ops = { |
150 | .ndo_init = loopback_dev_init, | |
00829823 | 151 | .ndo_start_xmit= loopback_xmit, |
6b10de38 | 152 | .ndo_get_stats64 = loopback_get_stats64, |
c02373bf SH |
153 | }; |
154 | ||
7fa6b066 | 155 | /* |
9e0db4b1 EB |
156 | * The loopback device is special. There is only one instance |
157 | * per network namespace. | |
7fa6b066 | 158 | */ |
854d8363 DL |
159 | static void loopback_setup(struct net_device *dev) |
160 | { | |
854d8363 | 161 | dev->mtu = (16 * 1024) + 20 + 20 + 12; |
854d8363 DL |
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*/ | |
854d8363 | 166 | dev->flags = IFF_LOOPBACK; |
93f154b5 | 167 | dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; |
cf0bdefd | 168 | dev->hw_features = NETIF_F_ALL_TSO | NETIF_F_UFO; |
854d8363 | 169 | dev->features = NETIF_F_SG | NETIF_F_FRAGLIST |
cf0bdefd MM |
170 | | NETIF_F_ALL_TSO |
171 | | NETIF_F_UFO | |
854d8363 | 172 | | NETIF_F_NO_CSUM |
cf0bdefd | 173 | | NETIF_F_RXCSUM |
854d8363 DL |
174 | | NETIF_F_HIGHDMA |
175 | | NETIF_F_LLTX | |
0553c891 | 176 | | NETIF_F_NETNS_LOCAL |
eed2a12f MB |
177 | | NETIF_F_VLAN_CHALLENGED |
178 | | NETIF_F_LOOPBACK; | |
854d8363 | 179 | dev->ethtool_ops = &loopback_ethtool_ops; |
3b04ddde | 180 | dev->header_ops = ð_header_ops; |
c02373bf SH |
181 | dev->netdev_ops = &loopback_ops; |
182 | dev->destructor = loopback_dev_free; | |
854d8363 | 183 | } |
de3cb747 | 184 | |
22783649 | 185 | /* Setup and register the loopback device. */ |
4665079c | 186 | static __net_init int loopback_net_init(struct net *net) |
1da177e4 | 187 | { |
854d8363 DL |
188 | struct net_device *dev; |
189 | int err; | |
190 | ||
191 | err = -ENOMEM; | |
192 | dev = alloc_netdev(0, "lo", loopback_setup); | |
193 | if (!dev) | |
194 | goto out; | |
aeed9e82 | 195 | |
c346dca1 | 196 | dev_net_set(dev, net); |
854d8363 | 197 | err = register_netdev(dev); |
aeed9e82 | 198 | if (err) |
854d8363 | 199 | goto out_free_netdev; |
aeed9e82 | 200 | |
2774c7ab | 201 | net->loopback_dev = dev; |
9d6dda32 | 202 | return 0; |
854d8363 | 203 | |
1da177e4 | 204 | |
854d8363 DL |
205 | out_free_netdev: |
206 | free_netdev(dev); | |
9d6dda32 | 207 | out: |
09ad9bc7 | 208 | if (net_eq(net, &init_net)) |
9d6dda32 PE |
209 | panic("loopback: Failed to register netdevice: %d\n", err); |
210 | return err; | |
854d8363 DL |
211 | } |
212 | ||
505d4f73 EB |
213 | /* Registered in net/core/dev.c */ |
214 | struct pernet_operations __net_initdata loopback_net_ops = { | |
2774c7ab | 215 | .init = loopback_net_init, |
2774c7ab | 216 | }; |