295 lines
6.8 KiB
C
295 lines
6.8 KiB
C
/* drivers/net/ifb.c:
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The purpose of this driver is to provide a device that allows
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for sharing of resources:
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1) qdiscs/policies that are per device as opposed to system wide.
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ifb allows for a device which can be redirected to thus providing
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an impression of sharing.
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2) Allows for queueing incoming traffic for shaping instead of
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dropping.
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The original concept is based on what is known as the IMQ
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driver initially written by Martin Devera, later rewritten
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by Patrick McHardy and then maintained by Andre Correa.
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You need the tc action mirror or redirect to feed this device
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packets.
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version
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2 of the License, or (at your option) any later version.
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Authors: Jamal Hadi Salim (2005)
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/netdevice.h>
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#include <linux/etherdevice.h>
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#include <linux/init.h>
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#include <linux/moduleparam.h>
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#include <net/pkt_sched.h>
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#define TX_TIMEOUT (2*HZ)
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#define TX_Q_LIMIT 32
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struct ifb_private {
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struct net_device_stats stats;
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struct tasklet_struct ifb_tasklet;
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int tasklet_pending;
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/* mostly debug stats leave in for now */
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unsigned long st_task_enter; /* tasklet entered */
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unsigned long st_txq_refl_try; /* transmit queue refill attempt */
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unsigned long st_rxq_enter; /* receive queue entered */
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unsigned long st_rx2tx_tran; /* receive to trasmit transfers */
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unsigned long st_rxq_notenter; /*receiveQ not entered, resched */
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unsigned long st_rx_frm_egr; /* received from egress path */
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unsigned long st_rx_frm_ing; /* received from ingress path */
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unsigned long st_rxq_check;
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unsigned long st_rxq_rsch;
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struct sk_buff_head rq;
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struct sk_buff_head tq;
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};
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static int numifbs = 2;
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static void ri_tasklet(unsigned long dev);
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static int ifb_xmit(struct sk_buff *skb, struct net_device *dev);
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static struct net_device_stats *ifb_get_stats(struct net_device *dev);
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static int ifb_open(struct net_device *dev);
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static int ifb_close(struct net_device *dev);
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static void ri_tasklet(unsigned long dev)
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{
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struct net_device *_dev = (struct net_device *)dev;
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struct ifb_private *dp = netdev_priv(_dev);
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struct net_device_stats *stats = &dp->stats;
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struct sk_buff *skb;
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dp->st_task_enter++;
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if ((skb = skb_peek(&dp->tq)) == NULL) {
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dp->st_txq_refl_try++;
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if (netif_tx_trylock(_dev)) {
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dp->st_rxq_enter++;
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while ((skb = skb_dequeue(&dp->rq)) != NULL) {
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skb_queue_tail(&dp->tq, skb);
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dp->st_rx2tx_tran++;
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}
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netif_tx_unlock(_dev);
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} else {
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/* reschedule */
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dp->st_rxq_notenter++;
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goto resched;
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}
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}
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while ((skb = skb_dequeue(&dp->tq)) != NULL) {
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u32 from = G_TC_FROM(skb->tc_verd);
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skb->tc_verd = 0;
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skb->tc_verd = SET_TC_NCLS(skb->tc_verd);
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stats->tx_packets++;
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stats->tx_bytes +=skb->len;
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if (from & AT_EGRESS) {
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dp->st_rx_frm_egr++;
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dev_queue_xmit(skb);
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} else if (from & AT_INGRESS) {
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dp->st_rx_frm_ing++;
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netif_rx(skb);
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} else {
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dev_kfree_skb(skb);
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stats->tx_dropped++;
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}
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}
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if (netif_tx_trylock(_dev)) {
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dp->st_rxq_check++;
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if ((skb = skb_peek(&dp->rq)) == NULL) {
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dp->tasklet_pending = 0;
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if (netif_queue_stopped(_dev))
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netif_wake_queue(_dev);
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} else {
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dp->st_rxq_rsch++;
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netif_tx_unlock(_dev);
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goto resched;
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}
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netif_tx_unlock(_dev);
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} else {
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resched:
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dp->tasklet_pending = 1;
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tasklet_schedule(&dp->ifb_tasklet);
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}
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}
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static void __init ifb_setup(struct net_device *dev)
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{
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/* Initialize the device structure. */
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dev->get_stats = ifb_get_stats;
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dev->hard_start_xmit = ifb_xmit;
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dev->open = &ifb_open;
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dev->stop = &ifb_close;
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/* Fill in device structure with ethernet-generic values. */
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ether_setup(dev);
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dev->tx_queue_len = TX_Q_LIMIT;
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dev->change_mtu = NULL;
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dev->flags |= IFF_NOARP;
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dev->flags &= ~IFF_MULTICAST;
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SET_MODULE_OWNER(dev);
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random_ether_addr(dev->dev_addr);
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}
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static int ifb_xmit(struct sk_buff *skb, struct net_device *dev)
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{
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struct ifb_private *dp = netdev_priv(dev);
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struct net_device_stats *stats = &dp->stats;
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int ret = 0;
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u32 from = G_TC_FROM(skb->tc_verd);
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stats->tx_packets++;
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stats->tx_bytes+=skb->len;
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if (!from || !skb->input_dev) {
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dropped:
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dev_kfree_skb(skb);
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stats->rx_dropped++;
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return ret;
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} else {
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/*
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* note we could be going
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* ingress -> egress or
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* egress -> ingress
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*/
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skb->dev = skb->input_dev;
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skb->input_dev = dev;
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if (from & AT_INGRESS) {
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skb_pull(skb, skb->dev->hard_header_len);
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} else {
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if (!(from & AT_EGRESS)) {
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goto dropped;
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}
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}
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}
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if (skb_queue_len(&dp->rq) >= dev->tx_queue_len) {
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netif_stop_queue(dev);
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}
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dev->trans_start = jiffies;
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skb_queue_tail(&dp->rq, skb);
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if (!dp->tasklet_pending) {
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dp->tasklet_pending = 1;
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tasklet_schedule(&dp->ifb_tasklet);
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}
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return ret;
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}
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static struct net_device_stats *ifb_get_stats(struct net_device *dev)
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{
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struct ifb_private *dp = netdev_priv(dev);
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struct net_device_stats *stats = &dp->stats;
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pr_debug("tasklets stats %ld:%ld:%ld:%ld:%ld:%ld:%ld:%ld:%ld \n",
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dp->st_task_enter, dp->st_txq_refl_try, dp->st_rxq_enter,
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dp->st_rx2tx_tran, dp->st_rxq_notenter, dp->st_rx_frm_egr,
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dp->st_rx_frm_ing, dp->st_rxq_check, dp->st_rxq_rsch);
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return stats;
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}
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static struct net_device **ifbs;
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/* Number of ifb devices to be set up by this module. */
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module_param(numifbs, int, 0);
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MODULE_PARM_DESC(numifbs, "Number of ifb devices");
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static int ifb_close(struct net_device *dev)
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{
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struct ifb_private *dp = netdev_priv(dev);
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tasklet_kill(&dp->ifb_tasklet);
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netif_stop_queue(dev);
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skb_queue_purge(&dp->rq);
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skb_queue_purge(&dp->tq);
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return 0;
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}
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static int ifb_open(struct net_device *dev)
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{
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struct ifb_private *dp = netdev_priv(dev);
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tasklet_init(&dp->ifb_tasklet, ri_tasklet, (unsigned long)dev);
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skb_queue_head_init(&dp->rq);
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skb_queue_head_init(&dp->tq);
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netif_start_queue(dev);
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return 0;
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}
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static int __init ifb_init_one(int index)
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{
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struct net_device *dev_ifb;
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int err;
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dev_ifb = alloc_netdev(sizeof(struct ifb_private),
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"ifb%d", ifb_setup);
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if (!dev_ifb)
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return -ENOMEM;
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if ((err = register_netdev(dev_ifb))) {
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free_netdev(dev_ifb);
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dev_ifb = NULL;
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} else {
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ifbs[index] = dev_ifb;
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}
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return err;
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}
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static void ifb_free_one(int index)
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{
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unregister_netdev(ifbs[index]);
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free_netdev(ifbs[index]);
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}
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static int __init ifb_init_module(void)
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{
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int i, err = 0;
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ifbs = kmalloc(numifbs * sizeof(void *), GFP_KERNEL);
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if (!ifbs)
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return -ENOMEM;
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for (i = 0; i < numifbs && !err; i++)
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err = ifb_init_one(i);
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if (err) {
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i--;
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while (--i >= 0)
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ifb_free_one(i);
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}
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return err;
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}
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static void __exit ifb_cleanup_module(void)
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{
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int i;
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for (i = 0; i < numifbs; i++)
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ifb_free_one(i);
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kfree(ifbs);
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}
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module_init(ifb_init_module);
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module_exit(ifb_cleanup_module);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Jamal Hadi Salim");
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