Commit | Line | Data |
---|---|---|
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 TH |
77 | struct pcpu_lstats __percpu *pcpu_lstats; |
78 | struct pcpu_lstats *lb_stats; | |
7eebb0b2 | 79 | int len; |
1da177e4 LT |
80 | |
81 | skb_orphan(skb); | |
82 | ||
7eebb0b2 | 83 | skb->protocol = eth_type_trans(skb, dev); |
1da177e4 | 84 | |
9e0db4b1 | 85 | /* it's OK to use per_cpu_ptr() because BHs are off */ |
47d74275 | 86 | pcpu_lstats = (void __percpu __force *)dev->ml_priv; |
ca0c9584 | 87 | lb_stats = this_cpu_ptr(pcpu_lstats); |
1da177e4 | 88 | |
7eebb0b2 ED |
89 | len = skb->len; |
90 | if (likely(netif_rx(skb) == NET_RX_SUCCESS)) { | |
5eaa0bd8 | 91 | u64_stats_update_begin(&lb_stats->syncp); |
7eebb0b2 ED |
92 | lb_stats->bytes += len; |
93 | lb_stats->packets++; | |
5eaa0bd8 | 94 | u64_stats_update_end(&lb_stats->syncp); |
7eebb0b2 ED |
95 | } else |
96 | lb_stats->drops++; | |
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 | { |
47d74275 | 104 | const struct pcpu_lstats __percpu *pcpu_lstats; |
6b10de38 ED |
105 | u64 bytes = 0; |
106 | u64 packets = 0; | |
107 | u64 drops = 0; | |
1da177e4 LT |
108 | int i; |
109 | ||
47d74275 | 110 | pcpu_lstats = (void __percpu __force *)dev->ml_priv; |
0fed4846 | 111 | for_each_possible_cpu(i) { |
5175c378 | 112 | const struct pcpu_lstats *lb_stats; |
5eaa0bd8 ED |
113 | u64 tbytes, tpackets; |
114 | unsigned int start; | |
1da177e4 | 115 | |
5f6d88b9 | 116 | lb_stats = per_cpu_ptr(pcpu_lstats, i); |
5eaa0bd8 ED |
117 | do { |
118 | start = u64_stats_fetch_begin(&lb_stats->syncp); | |
119 | tbytes = lb_stats->bytes; | |
120 | tpackets = lb_stats->packets; | |
121 | } while (u64_stats_fetch_retry(&lb_stats->syncp, start)); | |
7eebb0b2 | 122 | drops += lb_stats->drops; |
5eaa0bd8 ED |
123 | bytes += tbytes; |
124 | packets += tpackets; | |
1da177e4 | 125 | } |
5175c378 ED |
126 | stats->rx_packets = packets; |
127 | stats->tx_packets = packets; | |
7eebb0b2 ED |
128 | stats->rx_dropped = drops; |
129 | stats->rx_errors = drops; | |
130 | stats->rx_bytes = bytes; | |
131 | stats->tx_bytes = bytes; | |
1da177e4 LT |
132 | return stats; |
133 | } | |
134 | ||
7fa6b066 | 135 | static u32 always_on(struct net_device *dev) |
1da177e4 LT |
136 | { |
137 | return 1; | |
138 | } | |
139 | ||
7282d491 | 140 | static const struct ethtool_ops loopback_ethtool_ops = { |
7fa6b066 | 141 | .get_link = always_on, |
1da177e4 | 142 | .set_tso = ethtool_op_set_tso, |
7fa6b066 SH |
143 | .get_tx_csum = always_on, |
144 | .get_sg = always_on, | |
145 | .get_rx_csum = always_on, | |
1da177e4 LT |
146 | }; |
147 | ||
5f6d88b9 EB |
148 | static int loopback_dev_init(struct net_device *dev) |
149 | { | |
47d74275 | 150 | struct pcpu_lstats __percpu *lstats; |
5f6d88b9 EB |
151 | |
152 | lstats = alloc_percpu(struct pcpu_lstats); | |
153 | if (!lstats) | |
154 | return -ENOMEM; | |
155 | ||
47d74275 | 156 | dev->ml_priv = (void __force *)lstats; |
5f6d88b9 EB |
157 | return 0; |
158 | } | |
159 | ||
160 | static void loopback_dev_free(struct net_device *dev) | |
161 | { | |
47d74275 TH |
162 | struct pcpu_lstats __percpu *lstats = |
163 | (void __percpu __force *)dev->ml_priv; | |
5f6d88b9 EB |
164 | |
165 | free_percpu(lstats); | |
166 | free_netdev(dev); | |
167 | } | |
168 | ||
c02373bf SH |
169 | static const struct net_device_ops loopback_ops = { |
170 | .ndo_init = loopback_dev_init, | |
00829823 | 171 | .ndo_start_xmit= loopback_xmit, |
6b10de38 | 172 | .ndo_get_stats64 = loopback_get_stats64, |
c02373bf SH |
173 | }; |
174 | ||
7fa6b066 | 175 | /* |
9e0db4b1 EB |
176 | * The loopback device is special. There is only one instance |
177 | * per network namespace. | |
7fa6b066 | 178 | */ |
854d8363 DL |
179 | static void loopback_setup(struct net_device *dev) |
180 | { | |
854d8363 | 181 | dev->mtu = (16 * 1024) + 20 + 20 + 12; |
854d8363 DL |
182 | dev->hard_header_len = ETH_HLEN; /* 14 */ |
183 | dev->addr_len = ETH_ALEN; /* 6 */ | |
184 | dev->tx_queue_len = 0; | |
185 | dev->type = ARPHRD_LOOPBACK; /* 0x0001*/ | |
854d8363 | 186 | dev->flags = IFF_LOOPBACK; |
93f154b5 | 187 | dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; |
854d8363 | 188 | dev->features = NETIF_F_SG | NETIF_F_FRAGLIST |
854d8363 | 189 | | NETIF_F_TSO |
854d8363 DL |
190 | | NETIF_F_NO_CSUM |
191 | | NETIF_F_HIGHDMA | |
192 | | NETIF_F_LLTX | |
2d2c54e3 | 193 | | NETIF_F_NETNS_LOCAL; |
854d8363 | 194 | dev->ethtool_ops = &loopback_ethtool_ops; |
3b04ddde | 195 | dev->header_ops = ð_header_ops; |
c02373bf SH |
196 | dev->netdev_ops = &loopback_ops; |
197 | dev->destructor = loopback_dev_free; | |
854d8363 | 198 | } |
de3cb747 | 199 | |
22783649 | 200 | /* Setup and register the loopback device. */ |
4665079c | 201 | static __net_init int loopback_net_init(struct net *net) |
1da177e4 | 202 | { |
854d8363 DL |
203 | struct net_device *dev; |
204 | int err; | |
205 | ||
206 | err = -ENOMEM; | |
207 | dev = alloc_netdev(0, "lo", loopback_setup); | |
208 | if (!dev) | |
209 | goto out; | |
aeed9e82 | 210 | |
c346dca1 | 211 | dev_net_set(dev, net); |
854d8363 | 212 | err = register_netdev(dev); |
aeed9e82 | 213 | if (err) |
854d8363 | 214 | goto out_free_netdev; |
aeed9e82 | 215 | |
2774c7ab | 216 | net->loopback_dev = dev; |
9d6dda32 | 217 | return 0; |
854d8363 | 218 | |
1da177e4 | 219 | |
854d8363 DL |
220 | out_free_netdev: |
221 | free_netdev(dev); | |
9d6dda32 | 222 | out: |
09ad9bc7 | 223 | if (net_eq(net, &init_net)) |
9d6dda32 PE |
224 | panic("loopback: Failed to register netdevice: %d\n", err); |
225 | return err; | |
854d8363 DL |
226 | } |
227 | ||
505d4f73 EB |
228 | /* Registered in net/core/dev.c */ |
229 | struct pernet_operations __net_initdata loopback_net_ops = { | |
2774c7ab | 230 | .init = loopback_net_init, |
2774c7ab | 231 | }; |