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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 | 62 | struct pcpu_lstats { |
6b10de38 ED |
63 | u64 packets; |
64 | u64 bytes; | |
65 | #if BITS_PER_LONG==32 && defined(CONFIG_SMP) | |
66 | seqcount_t seq; | |
67 | #endif | |
7eebb0b2 | 68 | unsigned long drops; |
5175c378 | 69 | }; |
1da177e4 | 70 | |
6b10de38 ED |
71 | #if BITS_PER_LONG==32 && defined(CONFIG_SMP) |
72 | static void inline lstats_update_begin(struct pcpu_lstats *lstats) | |
73 | { | |
74 | write_seqcount_begin(&lstats->seq); | |
75 | } | |
76 | static void inline lstats_update_end(struct pcpu_lstats *lstats) | |
77 | { | |
78 | write_seqcount_end(&lstats->seq); | |
79 | } | |
80 | static void inline lstats_fetch_and_add(u64 *packets, u64 *bytes, const struct pcpu_lstats *lstats) | |
81 | { | |
82 | u64 tpackets, tbytes; | |
83 | unsigned int seq; | |
84 | ||
85 | do { | |
86 | seq = read_seqcount_begin(&lstats->seq); | |
87 | tpackets = lstats->packets; | |
88 | tbytes = lstats->bytes; | |
89 | } while (read_seqcount_retry(&lstats->seq, seq)); | |
90 | ||
91 | *packets += tpackets; | |
92 | *bytes += tbytes; | |
93 | } | |
94 | #else | |
95 | static void inline lstats_update_begin(struct pcpu_lstats *lstats) | |
96 | { | |
97 | } | |
98 | static void inline lstats_update_end(struct pcpu_lstats *lstats) | |
99 | { | |
100 | } | |
101 | static void inline lstats_fetch_and_add(u64 *packets, u64 *bytes, const struct pcpu_lstats *lstats) | |
102 | { | |
103 | *packets += lstats->packets; | |
104 | *bytes += lstats->bytes; | |
105 | } | |
106 | #endif | |
107 | ||
1da177e4 LT |
108 | /* |
109 | * The higher levels take care of making this non-reentrant (it's | |
110 | * called with bh's disabled). | |
111 | */ | |
61357325 SH |
112 | static netdev_tx_t loopback_xmit(struct sk_buff *skb, |
113 | struct net_device *dev) | |
1da177e4 | 114 | { |
47d74275 TH |
115 | struct pcpu_lstats __percpu *pcpu_lstats; |
116 | struct pcpu_lstats *lb_stats; | |
7eebb0b2 | 117 | int len; |
1da177e4 LT |
118 | |
119 | skb_orphan(skb); | |
120 | ||
7eebb0b2 | 121 | skb->protocol = eth_type_trans(skb, dev); |
1da177e4 | 122 | |
9e0db4b1 | 123 | /* it's OK to use per_cpu_ptr() because BHs are off */ |
47d74275 | 124 | pcpu_lstats = (void __percpu __force *)dev->ml_priv; |
ca0c9584 | 125 | lb_stats = this_cpu_ptr(pcpu_lstats); |
1da177e4 | 126 | |
7eebb0b2 ED |
127 | len = skb->len; |
128 | if (likely(netif_rx(skb) == NET_RX_SUCCESS)) { | |
6b10de38 | 129 | lstats_update_begin(lb_stats); |
7eebb0b2 ED |
130 | lb_stats->bytes += len; |
131 | lb_stats->packets++; | |
6b10de38 | 132 | lstats_update_end(lb_stats); |
7eebb0b2 ED |
133 | } else |
134 | lb_stats->drops++; | |
1da177e4 | 135 | |
6ed10654 | 136 | return NETDEV_TX_OK; |
1da177e4 LT |
137 | } |
138 | ||
6b10de38 | 139 | static struct rtnl_link_stats64 *loopback_get_stats64(struct net_device *dev) |
1da177e4 | 140 | { |
47d74275 | 141 | const struct pcpu_lstats __percpu *pcpu_lstats; |
6b10de38 ED |
142 | struct rtnl_link_stats64 *stats = &dev->stats64; |
143 | u64 bytes = 0; | |
144 | u64 packets = 0; | |
145 | u64 drops = 0; | |
1da177e4 LT |
146 | int i; |
147 | ||
47d74275 | 148 | pcpu_lstats = (void __percpu __force *)dev->ml_priv; |
0fed4846 | 149 | for_each_possible_cpu(i) { |
5175c378 | 150 | const struct pcpu_lstats *lb_stats; |
1da177e4 | 151 | |
5f6d88b9 | 152 | lb_stats = per_cpu_ptr(pcpu_lstats, i); |
6b10de38 | 153 | lstats_fetch_and_add(&packets, &bytes, lb_stats); |
7eebb0b2 | 154 | drops += lb_stats->drops; |
1da177e4 | 155 | } |
5175c378 ED |
156 | stats->rx_packets = packets; |
157 | stats->tx_packets = packets; | |
7eebb0b2 ED |
158 | stats->rx_dropped = drops; |
159 | stats->rx_errors = drops; | |
160 | stats->rx_bytes = bytes; | |
161 | stats->tx_bytes = bytes; | |
1da177e4 LT |
162 | return stats; |
163 | } | |
164 | ||
7fa6b066 | 165 | static u32 always_on(struct net_device *dev) |
1da177e4 LT |
166 | { |
167 | return 1; | |
168 | } | |
169 | ||
7282d491 | 170 | static const struct ethtool_ops loopback_ethtool_ops = { |
7fa6b066 | 171 | .get_link = always_on, |
1da177e4 | 172 | .set_tso = ethtool_op_set_tso, |
7fa6b066 SH |
173 | .get_tx_csum = always_on, |
174 | .get_sg = always_on, | |
175 | .get_rx_csum = always_on, | |
1da177e4 LT |
176 | }; |
177 | ||
5f6d88b9 EB |
178 | static int loopback_dev_init(struct net_device *dev) |
179 | { | |
47d74275 | 180 | struct pcpu_lstats __percpu *lstats; |
5f6d88b9 EB |
181 | |
182 | lstats = alloc_percpu(struct pcpu_lstats); | |
183 | if (!lstats) | |
184 | return -ENOMEM; | |
185 | ||
47d74275 | 186 | dev->ml_priv = (void __force *)lstats; |
5f6d88b9 EB |
187 | return 0; |
188 | } | |
189 | ||
190 | static void loopback_dev_free(struct net_device *dev) | |
191 | { | |
47d74275 TH |
192 | struct pcpu_lstats __percpu *lstats = |
193 | (void __percpu __force *)dev->ml_priv; | |
5f6d88b9 EB |
194 | |
195 | free_percpu(lstats); | |
196 | free_netdev(dev); | |
197 | } | |
198 | ||
c02373bf SH |
199 | static const struct net_device_ops loopback_ops = { |
200 | .ndo_init = loopback_dev_init, | |
00829823 | 201 | .ndo_start_xmit= loopback_xmit, |
6b10de38 | 202 | .ndo_get_stats64 = loopback_get_stats64, |
c02373bf SH |
203 | }; |
204 | ||
7fa6b066 | 205 | /* |
9e0db4b1 EB |
206 | * The loopback device is special. There is only one instance |
207 | * per network namespace. | |
7fa6b066 | 208 | */ |
854d8363 DL |
209 | static void loopback_setup(struct net_device *dev) |
210 | { | |
854d8363 | 211 | dev->mtu = (16 * 1024) + 20 + 20 + 12; |
854d8363 DL |
212 | dev->hard_header_len = ETH_HLEN; /* 14 */ |
213 | dev->addr_len = ETH_ALEN; /* 6 */ | |
214 | dev->tx_queue_len = 0; | |
215 | dev->type = ARPHRD_LOOPBACK; /* 0x0001*/ | |
854d8363 | 216 | dev->flags = IFF_LOOPBACK; |
93f154b5 | 217 | dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; |
854d8363 | 218 | dev->features = NETIF_F_SG | NETIF_F_FRAGLIST |
854d8363 | 219 | | NETIF_F_TSO |
854d8363 DL |
220 | | NETIF_F_NO_CSUM |
221 | | NETIF_F_HIGHDMA | |
222 | | NETIF_F_LLTX | |
2d2c54e3 | 223 | | NETIF_F_NETNS_LOCAL; |
854d8363 | 224 | dev->ethtool_ops = &loopback_ethtool_ops; |
3b04ddde | 225 | dev->header_ops = ð_header_ops; |
c02373bf SH |
226 | dev->netdev_ops = &loopback_ops; |
227 | dev->destructor = loopback_dev_free; | |
854d8363 | 228 | } |
de3cb747 | 229 | |
22783649 | 230 | /* Setup and register the loopback device. */ |
4665079c | 231 | static __net_init int loopback_net_init(struct net *net) |
1da177e4 | 232 | { |
854d8363 DL |
233 | struct net_device *dev; |
234 | int err; | |
235 | ||
236 | err = -ENOMEM; | |
237 | dev = alloc_netdev(0, "lo", loopback_setup); | |
238 | if (!dev) | |
239 | goto out; | |
aeed9e82 | 240 | |
c346dca1 | 241 | dev_net_set(dev, net); |
854d8363 | 242 | err = register_netdev(dev); |
aeed9e82 | 243 | if (err) |
854d8363 | 244 | goto out_free_netdev; |
aeed9e82 | 245 | |
2774c7ab | 246 | net->loopback_dev = dev; |
9d6dda32 | 247 | return 0; |
854d8363 | 248 | |
1da177e4 | 249 | |
854d8363 DL |
250 | out_free_netdev: |
251 | free_netdev(dev); | |
9d6dda32 | 252 | out: |
09ad9bc7 | 253 | if (net_eq(net, &init_net)) |
9d6dda32 PE |
254 | panic("loopback: Failed to register netdevice: %d\n", err); |
255 | return err; | |
854d8363 DL |
256 | } |
257 | ||
505d4f73 EB |
258 | /* Registered in net/core/dev.c */ |
259 | struct pernet_operations __net_initdata loopback_net_ops = { | |
2774c7ab | 260 | .init = loopback_net_init, |
2774c7ab | 261 | }; |