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; | |
67 | unsigned long drops; | |
5175c378 | 68 | }; |
1da177e4 | 69 | |
1da177e4 LT |
70 | /* |
71 | * The higher levels take care of making this non-reentrant (it's | |
72 | * called with bh's disabled). | |
73 | */ | |
61357325 SH |
74 | static netdev_tx_t loopback_xmit(struct sk_buff *skb, |
75 | struct net_device *dev) | |
1da177e4 | 76 | { |
47d74275 | 77 | struct pcpu_lstats *lb_stats; |
7eebb0b2 | 78 | int len; |
1da177e4 LT |
79 | |
80 | skb_orphan(skb); | |
81 | ||
7eebb0b2 | 82 | skb->protocol = eth_type_trans(skb, dev); |
1da177e4 | 83 | |
9e0db4b1 | 84 | /* it's OK to use per_cpu_ptr() because BHs are off */ |
a7855c78 | 85 | lb_stats = this_cpu_ptr(dev->lstats); |
1da177e4 | 86 | |
7eebb0b2 ED |
87 | len = skb->len; |
88 | if (likely(netif_rx(skb) == NET_RX_SUCCESS)) { | |
5eaa0bd8 | 89 | u64_stats_update_begin(&lb_stats->syncp); |
7eebb0b2 ED |
90 | lb_stats->bytes += len; |
91 | lb_stats->packets++; | |
5eaa0bd8 | 92 | u64_stats_update_end(&lb_stats->syncp); |
7eebb0b2 ED |
93 | } else |
94 | lb_stats->drops++; | |
1da177e4 | 95 | |
6ed10654 | 96 | return NETDEV_TX_OK; |
1da177e4 LT |
97 | } |
98 | ||
28172739 ED |
99 | static struct rtnl_link_stats64 *loopback_get_stats64(struct net_device *dev, |
100 | struct rtnl_link_stats64 *stats) | |
1da177e4 | 101 | { |
6b10de38 ED |
102 | u64 bytes = 0; |
103 | u64 packets = 0; | |
104 | u64 drops = 0; | |
1da177e4 LT |
105 | int i; |
106 | ||
0fed4846 | 107 | for_each_possible_cpu(i) { |
5175c378 | 108 | const struct pcpu_lstats *lb_stats; |
5eaa0bd8 ED |
109 | u64 tbytes, tpackets; |
110 | unsigned int start; | |
1da177e4 | 111 | |
a7855c78 | 112 | lb_stats = per_cpu_ptr(dev->lstats, i); |
5eaa0bd8 ED |
113 | do { |
114 | start = u64_stats_fetch_begin(&lb_stats->syncp); | |
115 | tbytes = lb_stats->bytes; | |
116 | tpackets = lb_stats->packets; | |
117 | } while (u64_stats_fetch_retry(&lb_stats->syncp, start)); | |
7eebb0b2 | 118 | drops += lb_stats->drops; |
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_dropped = drops; |
125 | stats->rx_errors = drops; | |
126 | stats->rx_bytes = bytes; | |
127 | stats->tx_bytes = bytes; | |
1da177e4 LT |
128 | return stats; |
129 | } | |
130 | ||
7fa6b066 | 131 | static u32 always_on(struct net_device *dev) |
1da177e4 LT |
132 | { |
133 | return 1; | |
134 | } | |
135 | ||
7282d491 | 136 | static const struct ethtool_ops loopback_ethtool_ops = { |
7fa6b066 | 137 | .get_link = always_on, |
1da177e4 | 138 | .set_tso = ethtool_op_set_tso, |
7fa6b066 SH |
139 | .get_tx_csum = always_on, |
140 | .get_sg = always_on, | |
141 | .get_rx_csum = always_on, | |
1da177e4 LT |
142 | }; |
143 | ||
5f6d88b9 EB |
144 | static int loopback_dev_init(struct net_device *dev) |
145 | { | |
a7855c78 ED |
146 | dev->lstats = alloc_percpu(struct pcpu_lstats); |
147 | if (!dev->lstats) | |
5f6d88b9 EB |
148 | return -ENOMEM; |
149 | ||
5f6d88b9 EB |
150 | return 0; |
151 | } | |
152 | ||
153 | static void loopback_dev_free(struct net_device *dev) | |
154 | { | |
a7855c78 | 155 | free_percpu(dev->lstats); |
5f6d88b9 EB |
156 | free_netdev(dev); |
157 | } | |
158 | ||
c02373bf SH |
159 | static const struct net_device_ops loopback_ops = { |
160 | .ndo_init = loopback_dev_init, | |
00829823 | 161 | .ndo_start_xmit= loopback_xmit, |
6b10de38 | 162 | .ndo_get_stats64 = loopback_get_stats64, |
c02373bf SH |
163 | }; |
164 | ||
7fa6b066 | 165 | /* |
9e0db4b1 EB |
166 | * The loopback device is special. There is only one instance |
167 | * per network namespace. | |
7fa6b066 | 168 | */ |
854d8363 DL |
169 | static void loopback_setup(struct net_device *dev) |
170 | { | |
854d8363 | 171 | dev->mtu = (16 * 1024) + 20 + 20 + 12; |
854d8363 DL |
172 | dev->hard_header_len = ETH_HLEN; /* 14 */ |
173 | dev->addr_len = ETH_ALEN; /* 6 */ | |
174 | dev->tx_queue_len = 0; | |
175 | dev->type = ARPHRD_LOOPBACK; /* 0x0001*/ | |
854d8363 | 176 | dev->flags = IFF_LOOPBACK; |
93f154b5 | 177 | dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; |
854d8363 | 178 | dev->features = NETIF_F_SG | NETIF_F_FRAGLIST |
854d8363 | 179 | | NETIF_F_TSO |
854d8363 DL |
180 | | NETIF_F_NO_CSUM |
181 | | NETIF_F_HIGHDMA | |
182 | | NETIF_F_LLTX | |
2d2c54e3 | 183 | | NETIF_F_NETNS_LOCAL; |
854d8363 | 184 | dev->ethtool_ops = &loopback_ethtool_ops; |
3b04ddde | 185 | dev->header_ops = ð_header_ops; |
c02373bf SH |
186 | dev->netdev_ops = &loopback_ops; |
187 | dev->destructor = loopback_dev_free; | |
854d8363 | 188 | } |
de3cb747 | 189 | |
22783649 | 190 | /* Setup and register the loopback device. */ |
4665079c | 191 | static __net_init int loopback_net_init(struct net *net) |
1da177e4 | 192 | { |
854d8363 DL |
193 | struct net_device *dev; |
194 | int err; | |
195 | ||
196 | err = -ENOMEM; | |
197 | dev = alloc_netdev(0, "lo", loopback_setup); | |
198 | if (!dev) | |
199 | goto out; | |
aeed9e82 | 200 | |
c346dca1 | 201 | dev_net_set(dev, net); |
854d8363 | 202 | err = register_netdev(dev); |
aeed9e82 | 203 | if (err) |
854d8363 | 204 | goto out_free_netdev; |
aeed9e82 | 205 | |
2774c7ab | 206 | net->loopback_dev = dev; |
9d6dda32 | 207 | return 0; |
854d8363 | 208 | |
1da177e4 | 209 | |
854d8363 DL |
210 | out_free_netdev: |
211 | free_netdev(dev); | |
9d6dda32 | 212 | out: |
09ad9bc7 | 213 | if (net_eq(net, &init_net)) |
9d6dda32 PE |
214 | panic("loopback: Failed to register netdevice: %d\n", err); |
215 | return err; | |
854d8363 DL |
216 | } |
217 | ||
505d4f73 EB |
218 | /* Registered in net/core/dev.c */ |
219 | struct pernet_operations __net_initdata loopback_net_ops = { | |
2774c7ab | 220 | .init = loopback_net_init, |
2774c7ab | 221 | }; |