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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/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>
55#include <linux/if_arp.h>
56#include <linux/ip.h>
57#include <linux/tcp.h>
58#include <linux/percpu.h>
59#include <net/net_namespace.h>
60#include <linux/u64_stats_sync.h>
61
62struct pcpu_lstats {
63 u64 packets;
64 u64 bytes;
65 struct u64_stats_sync syncp;
66};
67
68
69
70
71
72static netdev_tx_t loopback_xmit(struct sk_buff *skb,
73 struct net_device *dev)
74{
75 struct pcpu_lstats *lb_stats;
76 int len;
77
78 skb_orphan(skb);
79
80
81
82
83 skb_dst_force(skb);
84
85 skb->protocol = eth_type_trans(skb, dev);
86
87
88 lb_stats = this_cpu_ptr(dev->lstats);
89
90 len = skb->len;
91 if (likely(netif_rx(skb) == NET_RX_SUCCESS)) {
92 u64_stats_update_begin(&lb_stats->syncp);
93 lb_stats->bytes += len;
94 lb_stats->packets++;
95 u64_stats_update_end(&lb_stats->syncp);
96 }
97
98 return NETDEV_TX_OK;
99}
100
101static struct rtnl_link_stats64 *loopback_get_stats64(struct net_device *dev,
102 struct rtnl_link_stats64 *stats)
103{
104 u64 bytes = 0;
105 u64 packets = 0;
106 int i;
107
108 for_each_possible_cpu(i) {
109 const struct pcpu_lstats *lb_stats;
110 u64 tbytes, tpackets;
111 unsigned int start;
112
113 lb_stats = per_cpu_ptr(dev->lstats, i);
114 do {
115 start = u64_stats_fetch_begin_bh(&lb_stats->syncp);
116 tbytes = lb_stats->bytes;
117 tpackets = lb_stats->packets;
118 } while (u64_stats_fetch_retry_bh(&lb_stats->syncp, start));
119 bytes += tbytes;
120 packets += tpackets;
121 }
122 stats->rx_packets = packets;
123 stats->tx_packets = packets;
124 stats->rx_bytes = bytes;
125 stats->tx_bytes = bytes;
126 return stats;
127}
128
129static u32 always_on(struct net_device *dev)
130{
131 return 1;
132}
133
134static const struct ethtool_ops loopback_ethtool_ops = {
135 .get_link = always_on,
136};
137
138static int loopback_dev_init(struct net_device *dev)
139{
140 dev->lstats = alloc_percpu(struct pcpu_lstats);
141 if (!dev->lstats)
142 return -ENOMEM;
143
144 return 0;
145}
146
147static void loopback_dev_free(struct net_device *dev)
148{
149 dev_net(dev)->loopback_dev = NULL;
150 free_percpu(dev->lstats);
151 free_netdev(dev);
152}
153
154static const struct net_device_ops loopback_ops = {
155 .ndo_init = loopback_dev_init,
156 .ndo_start_xmit= loopback_xmit,
157 .ndo_get_stats64 = loopback_get_stats64,
158};
159
160
161
162
163
164static void loopback_setup(struct net_device *dev)
165{
166 dev->mtu = 64 * 1024;
167 dev->hard_header_len = ETH_HLEN;
168 dev->addr_len = ETH_ALEN;
169 dev->tx_queue_len = 0;
170 dev->type = ARPHRD_LOOPBACK;
171 dev->flags = IFF_LOOPBACK;
172 dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
173 dev->hw_features = NETIF_F_ALL_TSO | NETIF_F_UFO;
174 dev->features = NETIF_F_SG | NETIF_F_FRAGLIST
175 | NETIF_F_ALL_TSO
176 | NETIF_F_UFO
177 | NETIF_F_HW_CSUM
178 | NETIF_F_RXCSUM
179 | NETIF_F_HIGHDMA
180 | NETIF_F_LLTX
181 | NETIF_F_NETNS_LOCAL
182 | NETIF_F_VLAN_CHALLENGED
183 | NETIF_F_LOOPBACK;
184 dev->ethtool_ops = &loopback_ethtool_ops;
185 dev->header_ops = ð_header_ops;
186 dev->netdev_ops = &loopback_ops;
187 dev->destructor = loopback_dev_free;
188}
189
190
191static __net_init int loopback_net_init(struct net *net)
192{
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;
200
201 dev_net_set(dev, net);
202 err = register_netdev(dev);
203 if (err)
204 goto out_free_netdev;
205
206 BUG_ON(dev->ifindex != LOOPBACK_IFINDEX);
207 net->loopback_dev = dev;
208 return 0;
209
210
211out_free_netdev:
212 free_netdev(dev);
213out:
214 if (net_eq(net, &init_net))
215 panic("loopback: Failed to register netdevice: %d\n", err);
216 return err;
217}
218
219
220struct pernet_operations __net_initdata loopback_net_ops = {
221 .init = loopback_net_init,
222};
223