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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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C
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293// SPDX-License-Identifier: GPL-2.0-or-later/* * INET An implementation of the TCP/IP protocol suite for the LINUX * operating system. INET is implemented using the BSD Socket * interface as the means of communication with the user level. * * Pseudo-driver for the loopback interface. * * Version: @(#)loopback.c 1.0.4b 08/16/93 * * Authors: Ross Biro * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> * Donald Becker, <becker@scyld.com> * * Alan Cox : Fixed oddments for NET3.014 * Alan Cox : Rejig for NET3.029 snap #3 * Alan Cox : Fixed NET3.029 bugs and sped up * Larry McVoy : Tiny tweak to double performance * Alan Cox : Backed out LMV's tweak - the linux mm * can't take it... * Michael Griffith: Don't bother computing the checksums * on packets received on the loopback * interface. * Alexey Kuznetsov: Potential hang under some extreme * cases removed. */#include <linux/kernel.h>#include <linux/jiffies.h>#include <linux/module.h>#include <linux/interrupt.h>#include <linux/fs.h>#include <linux/types.h>#include <linux/string.h>#include <linux/socket.h>#include <linux/errno.h>#include <linux/fcntl.h>#include <linux/in.h>
#include <linux/uaccess.h>#include <linux/io.h>
#include <linux/inet.h>#include <linux/netdevice.h>#include <linux/etherdevice.h>#include <linux/skbuff.h>#include <linux/ethtool.h>#include <net/sch_generic.h>#include <net/sock.h>#include <net/checksum.h>#include <linux/if_ether.h> /* For the statistics structure. */#include <linux/if_arp.h> /* For ARPHRD_ETHER */#include <linux/ip.h>#include <linux/tcp.h>#include <linux/percpu.h>#include <linux/net_tstamp.h>#include <net/net_namespace.h>#include <net/netdev_lock.h>#include <linux/u64_stats_sync.h>
/* blackhole_netdev - a device used for dsts that are marked expired! * This is global device (instead of per-net-ns) since it's not needed * to be per-ns and gets initialized at boot time. */struct net_device *blackhole_netdev;EXPORT_SYMBOL(blackhole_netdev);
/* The higher levels take care of making this non-reentrant (it's * called with bh's disabled). */static netdev_tx_t loopback_xmit(struct sk_buff *skb, struct net_device *dev){ int len;
skb_tx_timestamp(skb);
/* do not fool net_timestamp_check() with various clock bases */ skb_clear_tstamp(skb);
skb_orphan(skb);
/* Before queueing this packet to __netif_rx(), * make sure dst is refcounted. */ skb_dst_force(skb);
skb->protocol = eth_type_trans(skb, dev);
len = skb->len; if (likely(__netif_rx(skb) == NET_RX_SUCCESS)) dev_lstats_add(dev, len);
return NETDEV_TX_OK;}
void dev_lstats_read(struct net_device *dev, u64 *packets, u64 *bytes){ int i;
*packets = 0; *bytes = 0;
for_each_possible_cpu(i) { const struct pcpu_lstats *lb_stats; u64 tbytes, tpackets; unsigned int start;
lb_stats = per_cpu_ptr(dev->lstats, i); do { start = u64_stats_fetch_begin(&lb_stats->syncp); tpackets = u64_stats_read(&lb_stats->packets); tbytes = u64_stats_read(&lb_stats->bytes); } while (u64_stats_fetch_retry(&lb_stats->syncp, start)); *bytes += tbytes; *packets += tpackets; }}EXPORT_SYMBOL(dev_lstats_read);
static void loopback_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats){ u64 packets, bytes;
dev_lstats_read(dev, &packets, &bytes);
stats->rx_packets = packets; stats->tx_packets = packets; stats->rx_bytes = bytes; stats->tx_bytes = bytes;}
static u32 always_on(struct net_device *dev){ return 1;}
static const struct ethtool_ops loopback_ethtool_ops = { .get_link = always_on, .get_ts_info = ethtool_op_get_ts_info,};
static int loopback_dev_init(struct net_device *dev){ netdev_lockdep_set_classes(dev); return 0;}
static void loopback_dev_free(struct net_device *dev){ dev_net(dev)->loopback_dev = NULL;}
static const struct net_device_ops loopback_ops = { .ndo_init = loopback_dev_init, .ndo_start_xmit = loopback_xmit, .ndo_get_stats64 = loopback_get_stats64, .ndo_set_mac_address = eth_mac_addr,};
static void gen_lo_setup(struct net_device *dev, unsigned int mtu, const struct ethtool_ops *eth_ops, const struct header_ops *hdr_ops, const struct net_device_ops *dev_ops, void (*dev_destructor)(struct net_device *dev)){ dev->mtu = mtu; dev->hard_header_len = ETH_HLEN; /* 14 */ dev->min_header_len = ETH_HLEN; /* 14 */ dev->addr_len = ETH_ALEN; /* 6 */ dev->type = ARPHRD_LOOPBACK; /* 0x0001*/ dev->flags = IFF_LOOPBACK; dev->priv_flags |= IFF_LIVE_ADDR_CHANGE | IFF_NO_QUEUE; dev->lltx = true; dev->netns_immutable = true; netif_keep_dst(dev); dev->hw_features = NETIF_F_GSO_SOFTWARE; dev->features = NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_GSO_SOFTWARE | NETIF_F_HW_CSUM | NETIF_F_RXCSUM | NETIF_F_SCTP_CRC | NETIF_F_HIGHDMA | NETIF_F_VLAN_CHALLENGED | NETIF_F_LOOPBACK; dev->ethtool_ops = eth_ops; dev->header_ops = hdr_ops; dev->netdev_ops = dev_ops; dev->needs_free_netdev = true; dev->pcpu_stat_type = NETDEV_PCPU_STAT_LSTATS; dev->priv_destructor = dev_destructor;
netif_set_tso_max_size(dev, GSO_MAX_SIZE);}
/* The loopback device is special. There is only one instance * per network namespace. */static void loopback_setup(struct net_device *dev){ gen_lo_setup(dev, (64 * 1024), &loopback_ethtool_ops, ð_header_ops, &loopback_ops, loopback_dev_free);}
/* Setup and register the loopback device. */static __net_init int loopback_net_init(struct net *net){ struct net_device *dev; int err;
err = -ENOMEM; dev = alloc_netdev(0, "lo", NET_NAME_PREDICTABLE, loopback_setup); if (!dev) goto out;
dev_net_set(dev, net); err = register_netdev(dev); if (err) goto out_free_netdev;
BUG_ON(dev->ifindex != LOOPBACK_IFINDEX); net->loopback_dev = dev; return 0;
out_free_netdev: free_netdev(dev);out: if (net_eq(net, &init_net)) panic("loopback: Failed to register netdevice: %d\n", err); return err;}
/* Registered in net/core/dev.c */struct pernet_operations __net_initdata loopback_net_ops = { .init = loopback_net_init,};
/* blackhole netdevice */static netdev_tx_t blackhole_netdev_xmit(struct sk_buff *skb, struct net_device *dev){ kfree_skb(skb); net_warn_ratelimited("%s(): Dropping skb.\n", __func__); return NETDEV_TX_OK;}
static int blackhole_neigh_output(struct neighbour *n, struct sk_buff *skb){ kfree_skb(skb); return 0;}
static int blackhole_neigh_construct(struct net_device *dev, struct neighbour *n){ n->output = blackhole_neigh_output; return 0;}
static const struct net_device_ops blackhole_netdev_ops = { .ndo_start_xmit = blackhole_netdev_xmit, .ndo_neigh_construct = blackhole_neigh_construct,};
/* This is a dst-dummy device used specifically for invalidated * DSTs and unlike loopback, this is not per-ns. */static void blackhole_netdev_setup(struct net_device *dev){ gen_lo_setup(dev, ETH_MIN_MTU, NULL, NULL, &blackhole_netdev_ops, NULL);}
/* Setup and register the blackhole_netdev. */static int __init blackhole_netdev_init(void){ blackhole_netdev = alloc_netdev(0, "blackhole_dev", NET_NAME_UNKNOWN, blackhole_netdev_setup); if (!blackhole_netdev) return -ENOMEM;
rtnl_net_lock(&init_net); dev_init_scheduler(blackhole_netdev); dev_activate(blackhole_netdev); rtnl_net_unlock(&init_net);
blackhole_netdev->flags |= IFF_UP | IFF_RUNNING;
return 0;}
device_initcall(blackhole_netdev_init);