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 | ||
1da177e4 LT |
44 | #include <asm/uaccess.h> |
45 | #include <asm/io.h> | |
46 | ||
47 | #include <linux/inet.h> | |
48 | #include <linux/netdevice.h> | |
49 | #include <linux/etherdevice.h> | |
50 | #include <linux/skbuff.h> | |
51 | #include <linux/ethtool.h> | |
52 | #include <net/sock.h> | |
53 | #include <net/checksum.h> | |
54 | #include <linux/if_ether.h> /* For the statistics structure. */ | |
55 | #include <linux/if_arp.h> /* For ARPHRD_ETHER */ | |
56 | #include <linux/ip.h> | |
57 | #include <linux/tcp.h> | |
58 | #include <linux/percpu.h> | |
2774c7ab | 59 | #include <net/net_namespace.h> |
5eaa0bd8 | 60 | #include <linux/u64_stats_sync.h> |
1da177e4 | 61 | |
5175c378 | 62 | struct pcpu_lstats { |
5eaa0bd8 ED |
63 | u64 packets; |
64 | u64 bytes; | |
65 | struct u64_stats_sync syncp; | |
5175c378 | 66 | }; |
1da177e4 | 67 | |
1da177e4 LT |
68 | /* |
69 | * The higher levels take care of making this non-reentrant (it's | |
70 | * called with bh's disabled). | |
71 | */ | |
61357325 SH |
72 | static netdev_tx_t loopback_xmit(struct sk_buff *skb, |
73 | struct net_device *dev) | |
1da177e4 | 74 | { |
47d74275 | 75 | struct pcpu_lstats *lb_stats; |
7eebb0b2 | 76 | int len; |
1da177e4 LT |
77 | |
78 | skb_orphan(skb); | |
79 | ||
794ed393 ED |
80 | /* Before queueing this packet to netif_rx(), |
81 | * make sure dst is refcounted. | |
82 | */ | |
83 | skb_dst_force(skb); | |
84 | ||
7eebb0b2 | 85 | skb->protocol = eth_type_trans(skb, dev); |
1da177e4 | 86 | |
9e0db4b1 | 87 | /* it's OK to use per_cpu_ptr() because BHs are off */ |
a7855c78 | 88 | lb_stats = this_cpu_ptr(dev->lstats); |
1da177e4 | 89 | |
7eebb0b2 ED |
90 | len = skb->len; |
91 | if (likely(netif_rx(skb) == NET_RX_SUCCESS)) { | |
5eaa0bd8 | 92 | u64_stats_update_begin(&lb_stats->syncp); |
7eebb0b2 ED |
93 | lb_stats->bytes += len; |
94 | lb_stats->packets++; | |
5eaa0bd8 | 95 | u64_stats_update_end(&lb_stats->syncp); |
caf586e5 | 96 | } |
1da177e4 | 97 | |
6ed10654 | 98 | return NETDEV_TX_OK; |
1da177e4 LT |
99 | } |
100 | ||
28172739 ED |
101 | static struct rtnl_link_stats64 *loopback_get_stats64(struct net_device *dev, |
102 | struct rtnl_link_stats64 *stats) | |
1da177e4 | 103 | { |
6b10de38 ED |
104 | u64 bytes = 0; |
105 | u64 packets = 0; | |
1da177e4 LT |
106 | int i; |
107 | ||
0fed4846 | 108 | for_each_possible_cpu(i) { |
5175c378 | 109 | const struct pcpu_lstats *lb_stats; |
5eaa0bd8 ED |
110 | u64 tbytes, tpackets; |
111 | unsigned int start; | |
1da177e4 | 112 | |
a7855c78 | 113 | lb_stats = per_cpu_ptr(dev->lstats, i); |
5eaa0bd8 | 114 | do { |
e3906486 | 115 | start = u64_stats_fetch_begin_bh(&lb_stats->syncp); |
5eaa0bd8 ED |
116 | tbytes = lb_stats->bytes; |
117 | tpackets = lb_stats->packets; | |
e3906486 | 118 | } while (u64_stats_fetch_retry_bh(&lb_stats->syncp, start)); |
5eaa0bd8 ED |
119 | bytes += tbytes; |
120 | packets += tpackets; | |
1da177e4 | 121 | } |
5175c378 ED |
122 | stats->rx_packets = packets; |
123 | stats->tx_packets = packets; | |
7eebb0b2 ED |
124 | stats->rx_bytes = bytes; |
125 | stats->tx_bytes = bytes; | |
1da177e4 LT |
126 | return stats; |
127 | } | |
128 | ||
7fa6b066 | 129 | static u32 always_on(struct net_device *dev) |
1da177e4 LT |
130 | { |
131 | return 1; | |
132 | } | |
133 | ||
7282d491 | 134 | static const struct ethtool_ops loopback_ethtool_ops = { |
7fa6b066 | 135 | .get_link = always_on, |
1da177e4 LT |
136 | }; |
137 | ||
5f6d88b9 EB |
138 | static int loopback_dev_init(struct net_device *dev) |
139 | { | |
827da44c | 140 | int i; |
a7855c78 ED |
141 | dev->lstats = alloc_percpu(struct pcpu_lstats); |
142 | if (!dev->lstats) | |
5f6d88b9 EB |
143 | return -ENOMEM; |
144 | ||
827da44c JS |
145 | for_each_possible_cpu(i) { |
146 | struct pcpu_lstats *lb_stats; | |
147 | lb_stats = per_cpu_ptr(dev->lstats, i); | |
148 | u64_stats_init(&lb_stats->syncp); | |
149 | } | |
5f6d88b9 EB |
150 | return 0; |
151 | } | |
152 | ||
153 | static void loopback_dev_free(struct net_device *dev) | |
154 | { | |
e05e9070 | 155 | dev_net(dev)->loopback_dev = NULL; |
a7855c78 | 156 | free_percpu(dev->lstats); |
5f6d88b9 EB |
157 | free_netdev(dev); |
158 | } | |
159 | ||
c02373bf SH |
160 | static const struct net_device_ops loopback_ops = { |
161 | .ndo_init = loopback_dev_init, | |
00829823 | 162 | .ndo_start_xmit= loopback_xmit, |
6b10de38 | 163 | .ndo_get_stats64 = loopback_get_stats64, |
c02373bf SH |
164 | }; |
165 | ||
7fa6b066 | 166 | /* |
9e0db4b1 EB |
167 | * The loopback device is special. There is only one instance |
168 | * per network namespace. | |
7fa6b066 | 169 | */ |
854d8363 DL |
170 | static void loopback_setup(struct net_device *dev) |
171 | { | |
0cf833ae | 172 | dev->mtu = 64 * 1024; |
854d8363 DL |
173 | dev->hard_header_len = ETH_HLEN; /* 14 */ |
174 | dev->addr_len = ETH_ALEN; /* 6 */ | |
175 | dev->tx_queue_len = 0; | |
176 | dev->type = ARPHRD_LOOPBACK; /* 0x0001*/ | |
854d8363 | 177 | dev->flags = IFF_LOOPBACK; |
93f154b5 | 178 | dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; |
cf0bdefd | 179 | dev->hw_features = NETIF_F_ALL_TSO | NETIF_F_UFO; |
854d8363 | 180 | dev->features = NETIF_F_SG | NETIF_F_FRAGLIST |
cf0bdefd MM |
181 | | NETIF_F_ALL_TSO |
182 | | NETIF_F_UFO | |
34324dc2 | 183 | | NETIF_F_HW_CSUM |
cf0bdefd | 184 | | NETIF_F_RXCSUM |
854d8363 DL |
185 | | NETIF_F_HIGHDMA |
186 | | NETIF_F_LLTX | |
0553c891 | 187 | | NETIF_F_NETNS_LOCAL |
eed2a12f MB |
188 | | NETIF_F_VLAN_CHALLENGED |
189 | | NETIF_F_LOOPBACK; | |
854d8363 | 190 | dev->ethtool_ops = &loopback_ethtool_ops; |
3b04ddde | 191 | dev->header_ops = ð_header_ops; |
c02373bf SH |
192 | dev->netdev_ops = &loopback_ops; |
193 | dev->destructor = loopback_dev_free; | |
854d8363 | 194 | } |
de3cb747 | 195 | |
22783649 | 196 | /* Setup and register the loopback device. */ |
4665079c | 197 | static __net_init int loopback_net_init(struct net *net) |
1da177e4 | 198 | { |
854d8363 DL |
199 | struct net_device *dev; |
200 | int err; | |
201 | ||
202 | err = -ENOMEM; | |
203 | dev = alloc_netdev(0, "lo", loopback_setup); | |
204 | if (!dev) | |
205 | goto out; | |
aeed9e82 | 206 | |
c346dca1 | 207 | dev_net_set(dev, net); |
854d8363 | 208 | err = register_netdev(dev); |
aeed9e82 | 209 | if (err) |
854d8363 | 210 | goto out_free_netdev; |
aeed9e82 | 211 | |
1fb9489b | 212 | BUG_ON(dev->ifindex != LOOPBACK_IFINDEX); |
2774c7ab | 213 | net->loopback_dev = dev; |
9d6dda32 | 214 | return 0; |
854d8363 | 215 | |
1da177e4 | 216 | |
854d8363 DL |
217 | out_free_netdev: |
218 | free_netdev(dev); | |
9d6dda32 | 219 | out: |
09ad9bc7 | 220 | if (net_eq(net, &init_net)) |
9d6dda32 PE |
221 | panic("loopback: Failed to register netdevice: %d\n", err); |
222 | return err; | |
854d8363 DL |
223 | } |
224 | ||
505d4f73 EB |
225 | /* Registered in net/core/dev.c */ |
226 | struct pernet_operations __net_initdata loopback_net_ops = { | |
2774c7ab | 227 | .init = loopback_net_init, |
2774c7ab | 228 | }; |