diff options
Diffstat (limited to 'linux/drivers/net/loopback.c')
| -rw-r--r-- | linux/drivers/net/loopback.c | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/linux/drivers/net/loopback.c b/linux/drivers/net/loopback.c new file mode 100644 index 000000000..1bc654a73 --- /dev/null +++ b/linux/drivers/net/loopback.c @@ -0,0 +1,226 @@ +/* + * 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 <linux/init.h> + +#include <asm/system.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> + +struct pcpu_lstats { + unsigned long packets; + unsigned long bytes; + unsigned long drops; +}; + +/* + * 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 *pcpu_lstats, *lb_stats; + int len; + + skb_orphan(skb); + + skb->protocol = eth_type_trans(skb, dev); + + /* it's OK to use per_cpu_ptr() because BHs are off */ + pcpu_lstats = dev->ml_priv; + lb_stats = per_cpu_ptr(pcpu_lstats, smp_processor_id()); + + len = skb->len; + if (likely(netif_rx(skb) == NET_RX_SUCCESS)) { + lb_stats->bytes += len; + lb_stats->packets++; + } else + lb_stats->drops++; + + return NETDEV_TX_OK; +} + +static struct net_device_stats *loopback_get_stats(struct net_device *dev) +{ + const struct pcpu_lstats *pcpu_lstats; + struct net_device_stats *stats = &dev->stats; + unsigned long bytes = 0; + unsigned long packets = 0; + unsigned long drops = 0; + int i; + + pcpu_lstats = dev->ml_priv; + for_each_possible_cpu(i) { + const struct pcpu_lstats *lb_stats; + + lb_stats = per_cpu_ptr(pcpu_lstats, i); + bytes += lb_stats->bytes; + packets += lb_stats->packets; + drops += lb_stats->drops; + } + stats->rx_packets = packets; + stats->tx_packets = packets; + stats->rx_dropped = drops; + stats->rx_errors = drops; + 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, + .set_tso = ethtool_op_set_tso, + .get_tx_csum = always_on, + .get_sg = always_on, + .get_rx_csum = always_on, +}; + +static int loopback_dev_init(struct net_device *dev) +{ + struct pcpu_lstats *lstats; + + lstats = alloc_percpu(struct pcpu_lstats); + if (!lstats) + return -ENOMEM; + + dev->ml_priv = lstats; + return 0; +} + +static void loopback_dev_free(struct net_device *dev) +{ + struct pcpu_lstats *lstats = dev->ml_priv; + + free_percpu(lstats); + free_netdev(dev); +} + +static const struct net_device_ops loopback_ops = { + .ndo_init = loopback_dev_init, + .ndo_start_xmit= loopback_xmit, + .ndo_get_stats = loopback_get_stats, +}; + +/* + * The loopback device is special. There is only one instance + * per network namespace. + */ +static void loopback_setup(struct net_device *dev) +{ + dev->mtu = (16 * 1024) + 20 + 20 + 12; + 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_XMIT_DST_RELEASE; + dev->features = NETIF_F_SG | NETIF_F_FRAGLIST + | NETIF_F_TSO + | NETIF_F_NO_CSUM + | NETIF_F_HIGHDMA + | NETIF_F_LLTX + | NETIF_F_NETNS_LOCAL; + 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", loopback_setup); + if (!dev) + goto out; + + dev_net_set(dev, net); + err = register_netdev(dev); + if (err) + goto out_free_netdev; + + net->loopback_dev = dev; + return 0; + + +out_free_netdev: + free_netdev(dev); +out: + if (net == &init_net) + panic("loopback: Failed to register netdevice: %d\n", err); + return err; +} + +static __net_exit void loopback_net_exit(struct net *net) +{ + struct net_device *dev = net->loopback_dev; + + unregister_netdev(dev); +} + +/* Registered in net/core/dev.c */ +struct pernet_operations __net_initdata loopback_net_ops = { + .init = loopback_net_init, + .exit = loopback_net_exit, +}; |