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[/] [or1k/] [trunk/] [rc203soc/] [sw/] [uClinux/] [drivers/] [net/] [loopback.c] - Rev 1772
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/* * 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, <bir7@leland.Stanford.Edu> * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> * Donald Becker, <becker@cesdis.gsfc.nasa.gov> * * 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/config.h> #include <linux/kernel.h> #include <linux/sched.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/system.h> #include <asm/segment.h> #include <asm/io.h> #include <linux/inet.h> #include <linux/netdevice.h> #include <linux/etherdevice.h> #include <linux/skbuff.h> #include <net/sock.h> #include <linux/if_ether.h> /* For the statistics structure. */ #include <linux/if_arp.h> /* For ARPHRD_ETHER */ #define LOOPBACK_MTU (PAGE_SIZE*7/8) /* * The higher levels take care of making this non-reentrant (it's * called with bh's disabled). */ static int loopback_xmit(struct sk_buff *skb, struct device *dev) { struct enet_statistics *stats = (struct enet_statistics *)dev->priv; int unlock=1; if (skb == NULL || dev == NULL) return(0); /* * Optimise so buffers with skb->free=1 are not copied but * instead are lobbed from tx queue to rx queue */ if(skb->free==0) { struct sk_buff *skb2=skb; skb=skb_clone(skb, GFP_ATOMIC); /* Clone the buffer */ dev_kfree_skb(skb2, FREE_WRITE); if(skb==NULL) return 0; unlock=0; } else if(skb->sk) { /* * Packet sent but looped back around. Cease to charge * the socket for the frame. */ atomic_sub(skb->truesize, &skb->sk->wmem_alloc); skb->sk->write_space(skb->sk); } skb->protocol=eth_type_trans(skb,dev); skb->dev=dev; #ifndef LOOPBACK_MUST_CHECKSUM skb->ip_summed = CHECKSUM_UNNECESSARY; #endif netif_rx(skb); if(unlock) skb_device_unlock(skb); stats->rx_packets++; stats->tx_packets++; return(0); } static struct enet_statistics *get_stats(struct device *dev) { return (struct enet_statistics *)dev->priv; } static int loopback_open(struct device *dev) { dev->flags|=IFF_LOOPBACK; return 0; } /* Initialize the rest of the LOOPBACK device. */ int loopback_init(struct device *dev) { int i; dev->mtu = LOOPBACK_MTU; dev->tbusy = 0; dev->hard_start_xmit = loopback_xmit; dev->hard_header = eth_header; dev->hard_header_len = ETH_HLEN; /* 14 */ dev->addr_len = ETH_ALEN; /* 6 */ dev->tx_queue_len = 50000; /* No limit on loopback */ dev->type = ARPHRD_LOOPBACK; /* 0x0001 */ dev->rebuild_header = eth_rebuild_header; dev->open = loopback_open; dev->flags = IFF_LOOPBACK|IFF_BROADCAST; dev->family = AF_INET; #ifdef CONFIG_INET dev->pa_addr = in_aton("127.0.0.1"); dev->pa_brdaddr = in_aton("127.255.255.255"); dev->pa_mask = in_aton("255.0.0.0"); dev->pa_alen = 4; #endif dev->priv = kmalloc(sizeof(struct enet_statistics), GFP_KERNEL); if (dev->priv == NULL) return -ENOMEM; memset(dev->priv, 0, sizeof(struct enet_statistics)); dev->get_stats = get_stats; /* * Fill in the generic fields of the device structure. */ for (i = 0; i < DEV_NUMBUFFS; i++) skb_queue_head_init(&dev->buffs[i]); return(0); };
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