diff options
Diffstat (limited to 'drivers/net/loopback.c')
| -rw-r--r-- | drivers/net/loopback.c | 223 |
1 files changed, 223 insertions, 0 deletions
diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c new file mode 100644 index 000000000..c76283c2f --- /dev/null +++ b/drivers/net/loopback.c @@ -0,0 +1,223 @@ +/* + * 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. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ +#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 <asm/uaccess.h> +#include <asm/io.h> + +#include <linux/inet.h> +#include <linux/netdevice.h> +#include <linux/etherdevice.h> +#include <linux/skbuff.h> +#include <linux/ethtool.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 <net/net_namespace.h> +#include <linux/u64_stats_sync.h> + +struct pcpu_lstats { + u64 packets; + u64 bytes; + struct u64_stats_sync syncp; +}; + +/* + * 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) +{ + struct pcpu_lstats *lb_stats; + int len; + + 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); + + /* it's OK to use per_cpu_ptr() because BHs are off */ + lb_stats = this_cpu_ptr(dev->lstats); + + len = skb->len; + if (likely(netif_rx(skb) == NET_RX_SUCCESS)) { + u64_stats_update_begin(&lb_stats->syncp); + lb_stats->bytes += len; + lb_stats->packets++; + u64_stats_update_end(&lb_stats->syncp); + } + + return NETDEV_TX_OK; +} + +static struct rtnl_link_stats64 *loopback_get_stats64(struct net_device *dev, + struct rtnl_link_stats64 *stats) +{ + u64 bytes = 0; + u64 packets = 0; + int i; + + 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_irq(&lb_stats->syncp); + tbytes = lb_stats->bytes; + tpackets = lb_stats->packets; + } while (u64_stats_fetch_retry_irq(&lb_stats->syncp, start)); + bytes += tbytes; + packets += tpackets; + } + stats->rx_packets = packets; + stats->tx_packets = packets; + stats->rx_bytes = bytes; + stats->tx_bytes = bytes; + return stats; +} + +static u32 always_on(struct net_device *dev) +{ + return 1; +} + +static const struct ethtool_ops loopback_ethtool_ops = { + .get_link = always_on, +}; + +static int loopback_dev_init(struct net_device *dev) +{ + dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats); + if (!dev->lstats) + return -ENOMEM; + return 0; +} + +static void loopback_dev_free(struct net_device *dev) +{ + dev_net(dev)->loopback_dev = NULL; + free_percpu(dev->lstats); + free_netdev(dev); +} + +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, +}; + +/* + * The loopback device is special. There is only one instance + * per network namespace. + */ +static void loopback_setup(struct net_device *dev) +{ + dev->mtu = 64 * 1024; + dev->hard_header_len = ETH_HLEN; /* 14 */ + dev->addr_len = ETH_ALEN; /* 6 */ + dev->tx_queue_len = 0; + dev->type = ARPHRD_LOOPBACK; /* 0x0001*/ + dev->flags = IFF_LOOPBACK; + dev->priv_flags |= IFF_LIVE_ADDR_CHANGE; + netif_keep_dst(dev); + dev->hw_features = NETIF_F_ALL_TSO | NETIF_F_UFO; + dev->features = NETIF_F_SG | NETIF_F_FRAGLIST + | NETIF_F_ALL_TSO + | NETIF_F_UFO + | NETIF_F_HW_CSUM + | NETIF_F_RXCSUM + | NETIF_F_SCTP_CSUM + | NETIF_F_HIGHDMA + | NETIF_F_LLTX + | NETIF_F_NETNS_LOCAL + | NETIF_F_VLAN_CHALLENGED + | NETIF_F_LOOPBACK; + dev->ethtool_ops = &loopback_ethtool_ops; + dev->header_ops = ð_header_ops; + dev->netdev_ops = &loopback_ops; + dev->destructor = 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_UNKNOWN, 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, +}; |