ifb.c revision 253af4235d24ddfcd9f5403485e9273b33d8fa5e
1/* drivers/net/ifb.c: 2 3 The purpose of this driver is to provide a device that allows 4 for sharing of resources: 5 6 1) qdiscs/policies that are per device as opposed to system wide. 7 ifb allows for a device which can be redirected to thus providing 8 an impression of sharing. 9 10 2) Allows for queueing incoming traffic for shaping instead of 11 dropping. 12 13 The original concept is based on what is known as the IMQ 14 driver initially written by Martin Devera, later rewritten 15 by Patrick McHardy and then maintained by Andre Correa. 16 17 You need the tc action mirror or redirect to feed this device 18 packets. 19 20 This program is free software; you can redistribute it and/or 21 modify it under the terms of the GNU General Public License 22 as published by the Free Software Foundation; either version 23 2 of the License, or (at your option) any later version. 24 25 Authors: Jamal Hadi Salim (2005) 26 27*/ 28 29 30#include <linux/config.h> 31#include <linux/module.h> 32#include <linux/kernel.h> 33#include <linux/netdevice.h> 34#include <linux/etherdevice.h> 35#include <linux/init.h> 36#include <linux/moduleparam.h> 37#include <net/pkt_sched.h> 38 39#define TX_TIMEOUT (2*HZ) 40 41#define TX_Q_LIMIT 32 42struct ifb_private { 43 struct net_device_stats stats; 44 struct tasklet_struct ifb_tasklet; 45 int tasklet_pending; 46 /* mostly debug stats leave in for now */ 47 unsigned long st_task_enter; /* tasklet entered */ 48 unsigned long st_txq_refl_try; /* transmit queue refill attempt */ 49 unsigned long st_rxq_enter; /* receive queue entered */ 50 unsigned long st_rx2tx_tran; /* receive to trasmit transfers */ 51 unsigned long st_rxq_notenter; /*receiveQ not entered, resched */ 52 unsigned long st_rx_frm_egr; /* received from egress path */ 53 unsigned long st_rx_frm_ing; /* received from ingress path */ 54 unsigned long st_rxq_check; 55 unsigned long st_rxq_rsch; 56 struct sk_buff_head rq; 57 struct sk_buff_head tq; 58}; 59 60static int numifbs = 1; 61 62static void ri_tasklet(unsigned long dev); 63static int ifb_xmit(struct sk_buff *skb, struct net_device *dev); 64static struct net_device_stats *ifb_get_stats(struct net_device *dev); 65static int ifb_open(struct net_device *dev); 66static int ifb_close(struct net_device *dev); 67 68static void ri_tasklet(unsigned long dev) 69{ 70 71 struct net_device *_dev = (struct net_device *)dev; 72 struct ifb_private *dp = netdev_priv(_dev); 73 struct net_device_stats *stats = &dp->stats; 74 struct sk_buff *skb; 75 76 dp->st_task_enter++; 77 if ((skb = skb_peek(&dp->tq)) == NULL) { 78 dp->st_txq_refl_try++; 79 if (spin_trylock(&_dev->xmit_lock)) { 80 dp->st_rxq_enter++; 81 while ((skb = skb_dequeue(&dp->rq)) != NULL) { 82 skb_queue_tail(&dp->tq, skb); 83 dp->st_rx2tx_tran++; 84 } 85 spin_unlock(&_dev->xmit_lock); 86 } else { 87 /* reschedule */ 88 dp->st_rxq_notenter++; 89 goto resched; 90 } 91 } 92 93 while ((skb = skb_dequeue(&dp->tq)) != NULL) { 94 u32 from = G_TC_FROM(skb->tc_verd); 95 96 skb->tc_verd = 0; 97 skb->tc_verd = SET_TC_NCLS(skb->tc_verd); 98 stats->tx_packets++; 99 stats->tx_bytes +=skb->len; 100 if (from & AT_EGRESS) { 101 dp->st_rx_frm_egr++; 102 dev_queue_xmit(skb); 103 } else if (from & AT_INGRESS) { 104 105 dp->st_rx_frm_ing++; 106 netif_rx(skb); 107 } else { 108 dev_kfree_skb(skb); 109 stats->tx_dropped++; 110 } 111 } 112 113 if (spin_trylock(&_dev->xmit_lock)) { 114 dp->st_rxq_check++; 115 if ((skb = skb_peek(&dp->rq)) == NULL) { 116 dp->tasklet_pending = 0; 117 if (netif_queue_stopped(_dev)) 118 netif_wake_queue(_dev); 119 } else { 120 dp->st_rxq_rsch++; 121 spin_unlock(&_dev->xmit_lock); 122 goto resched; 123 } 124 spin_unlock(&_dev->xmit_lock); 125 } else { 126resched: 127 dp->tasklet_pending = 1; 128 tasklet_schedule(&dp->ifb_tasklet); 129 } 130 131} 132 133static void __init ifb_setup(struct net_device *dev) 134{ 135 /* Initialize the device structure. */ 136 dev->get_stats = ifb_get_stats; 137 dev->hard_start_xmit = ifb_xmit; 138 dev->open = &ifb_open; 139 dev->stop = &ifb_close; 140 141 /* Fill in device structure with ethernet-generic values. */ 142 ether_setup(dev); 143 dev->tx_queue_len = TX_Q_LIMIT; 144 dev->change_mtu = NULL; 145 dev->flags |= IFF_NOARP; 146 dev->flags &= ~IFF_MULTICAST; 147 SET_MODULE_OWNER(dev); 148 random_ether_addr(dev->dev_addr); 149} 150 151static int ifb_xmit(struct sk_buff *skb, struct net_device *dev) 152{ 153 struct ifb_private *dp = netdev_priv(dev); 154 struct net_device_stats *stats = &dp->stats; 155 int ret = 0; 156 u32 from = G_TC_FROM(skb->tc_verd); 157 158 stats->tx_packets++; 159 stats->tx_bytes+=skb->len; 160 161 if (!from || !skb->input_dev) { 162dropped: 163 dev_kfree_skb(skb); 164 stats->rx_dropped++; 165 return ret; 166 } else { 167 /* 168 * note we could be going 169 * ingress -> egress or 170 * egress -> ingress 171 */ 172 skb->dev = skb->input_dev; 173 skb->input_dev = dev; 174 if (from & AT_INGRESS) { 175 skb_pull(skb, skb->dev->hard_header_len); 176 } else { 177 if (!(from & AT_EGRESS)) { 178 goto dropped; 179 } 180 } 181 } 182 183 if (skb_queue_len(&dp->rq) >= dev->tx_queue_len) { 184 netif_stop_queue(dev); 185 } 186 187 dev->trans_start = jiffies; 188 skb_queue_tail(&dp->rq, skb); 189 if (!dp->tasklet_pending) { 190 dp->tasklet_pending = 1; 191 tasklet_schedule(&dp->ifb_tasklet); 192 } 193 194 return ret; 195} 196 197static struct net_device_stats *ifb_get_stats(struct net_device *dev) 198{ 199 struct ifb_private *dp = netdev_priv(dev); 200 struct net_device_stats *stats = &dp->stats; 201 202 pr_debug("tasklets stats %ld:%ld:%ld:%ld:%ld:%ld:%ld:%ld:%ld \n", 203 dp->st_task_enter, dp->st_txq_refl_try, dp->st_rxq_enter, 204 dp->st_rx2tx_tran dp->st_rxq_notenter, dp->st_rx_frm_egr, 205 dp->st_rx_frm_ing, dp->st_rxq_check, dp->st_rxq_rsch ); 206 207 return stats; 208} 209 210static struct net_device **ifbs; 211 212/* Number of ifb devices to be set up by this module. */ 213module_param(numifbs, int, 0); 214MODULE_PARM_DESC(numifbs, "Number of ifb devices"); 215 216static int ifb_close(struct net_device *dev) 217{ 218 struct ifb_private *dp = netdev_priv(dev); 219 220 tasklet_kill(&dp->ifb_tasklet); 221 netif_stop_queue(dev); 222 skb_queue_purge(&dp->rq); 223 skb_queue_purge(&dp->tq); 224 return 0; 225} 226 227static int ifb_open(struct net_device *dev) 228{ 229 struct ifb_private *dp = netdev_priv(dev); 230 231 tasklet_init(&dp->ifb_tasklet, ri_tasklet, (unsigned long)dev); 232 skb_queue_head_init(&dp->rq); 233 skb_queue_head_init(&dp->tq); 234 netif_start_queue(dev); 235 236 return 0; 237} 238 239static int __init ifb_init_one(int index) 240{ 241 struct net_device *dev_ifb; 242 int err; 243 244 dev_ifb = alloc_netdev(sizeof(struct ifb_private), 245 "ifb%d", ifb_setup); 246 247 if (!dev_ifb) 248 return -ENOMEM; 249 250 if ((err = register_netdev(dev_ifb))) { 251 free_netdev(dev_ifb); 252 dev_ifb = NULL; 253 } else { 254 ifbs[index] = dev_ifb; 255 } 256 257 return err; 258} 259 260static void ifb_free_one(int index) 261{ 262 unregister_netdev(ifbs[index]); 263 free_netdev(ifbs[index]); 264} 265 266static int __init ifb_init_module(void) 267{ 268 int i, err = 0; 269 ifbs = kmalloc(numifbs * sizeof(void *), GFP_KERNEL); 270 if (!ifbs) 271 return -ENOMEM; 272 for (i = 0; i < numifbs && !err; i++) 273 err = ifb_init_one(i); 274 if (err) { 275 while (--i >= 0) 276 ifb_free_one(i); 277 } 278 279 return err; 280} 281 282static void __exit ifb_cleanup_module(void) 283{ 284 int i; 285 286 for (i = 0; i < numifbs; i++) 287 ifb_free_one(i); 288 kfree(ifbs); 289} 290 291module_init(ifb_init_module); 292module_exit(ifb_cleanup_module); 293MODULE_LICENSE("GPL"); 294MODULE_AUTHOR("Jamal Hadi Salim"); 295