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/module.h> 31 #include <linux/kernel.h> 32 #include <linux/netdevice.h> 33 #include <linux/etherdevice.h> 34 #include <linux/init.h> 35 #include <linux/moduleparam.h> 36 #include <net/pkt_sched.h> 37 38 #define TX_TIMEOUT (2*HZ) 39 40 #define TX_Q_LIMIT 32 41 struct ifb_private { 42 struct net_device_stats stats; 43 struct tasklet_struct ifb_tasklet; 44 int tasklet_pending; 45 /* mostly debug stats leave in for now */ 46 unsigned long st_task_enter; /* tasklet entered */ 47 unsigned long st_txq_refl_try; /* transmit queue refill attempt */ 48 unsigned long st_rxq_enter; /* receive queue entered */ 49 unsigned long st_rx2tx_tran; /* receive to trasmit transfers */ 50 unsigned long st_rxq_notenter; /*receiveQ not entered, resched */ 51 unsigned long st_rx_frm_egr; /* received from egress path */ 52 unsigned long st_rx_frm_ing; /* received from ingress path */ 53 unsigned long st_rxq_check; 54 unsigned long st_rxq_rsch; 55 struct sk_buff_head rq; 56 struct sk_buff_head tq; 57 }; 58 59 static int numifbs = 2; 60 61 static void ri_tasklet(unsigned long dev); 62 static int ifb_xmit(struct sk_buff *skb, struct net_device *dev); 63 static struct net_device_stats *ifb_get_stats(struct net_device *dev); 64 static int ifb_open(struct net_device *dev); 65 static int ifb_close(struct net_device *dev); 66 67 static void ri_tasklet(unsigned long dev) 68 { 69 70 struct net_device *_dev = (struct net_device *)dev; 71 struct ifb_private *dp = netdev_priv(_dev); 72 struct net_device_stats *stats = &dp->stats; 73 struct sk_buff *skb; 74 75 dp->st_task_enter++; 76 if ((skb = skb_peek(&dp->tq)) == NULL) { 77 dp->st_txq_refl_try++; 78 if (netif_tx_trylock(_dev)) { 79 dp->st_rxq_enter++; 80 while ((skb = skb_dequeue(&dp->rq)) != NULL) { 81 skb_queue_tail(&dp->tq, skb); 82 dp->st_rx2tx_tran++; 83 } 84 netif_tx_unlock(_dev); 85 } else { 86 /* reschedule */ 87 dp->st_rxq_notenter++; 88 goto resched; 89 } 90 } 91 92 while ((skb = skb_dequeue(&dp->tq)) != NULL) { 93 u32 from = G_TC_FROM(skb->tc_verd); 94 95 skb->tc_verd = 0; 96 skb->tc_verd = SET_TC_NCLS(skb->tc_verd); 97 stats->tx_packets++; 98 stats->tx_bytes +=skb->len; 99 if (from & AT_EGRESS) { 100 dp->st_rx_frm_egr++; 101 dev_queue_xmit(skb); 102 } else if (from & AT_INGRESS) { 103 104 dp->st_rx_frm_ing++; 105 netif_rx(skb); 106 } else { 107 dev_kfree_skb(skb); 108 stats->tx_dropped++; 109 } 110 } 111 112 if (netif_tx_trylock(_dev)) { 113 dp->st_rxq_check++; 114 if ((skb = skb_peek(&dp->rq)) == NULL) { 115 dp->tasklet_pending = 0; 116 if (netif_queue_stopped(_dev)) 117 netif_wake_queue(_dev); 118 } else { 119 dp->st_rxq_rsch++; 120 netif_tx_unlock(_dev); 121 goto resched; 122 } 123 netif_tx_unlock(_dev); 124 } else { 125 resched: 126 dp->tasklet_pending = 1; 127 tasklet_schedule(&dp->ifb_tasklet); 128 } 129 130 } 131 132 static void __init ifb_setup(struct net_device *dev) 133 { 134 /* Initialize the device structure. */ 135 dev->get_stats = ifb_get_stats; 136 dev->hard_start_xmit = ifb_xmit; 137 dev->open = &ifb_open; 138 dev->stop = &ifb_close; 139 140 /* Fill in device structure with ethernet-generic values. */ 141 ether_setup(dev); 142 dev->tx_queue_len = TX_Q_LIMIT; 143 dev->change_mtu = NULL; 144 dev->flags |= IFF_NOARP; 145 dev->flags &= ~IFF_MULTICAST; 146 SET_MODULE_OWNER(dev); 147 random_ether_addr(dev->dev_addr); 148 } 149 150 static int ifb_xmit(struct sk_buff *skb, struct net_device *dev) 151 { 152 struct ifb_private *dp = netdev_priv(dev); 153 struct net_device_stats *stats = &dp->stats; 154 int ret = 0; 155 u32 from = G_TC_FROM(skb->tc_verd); 156 157 stats->tx_packets++; 158 stats->tx_bytes+=skb->len; 159 160 if (!from || !skb->input_dev) { 161 dropped: 162 dev_kfree_skb(skb); 163 stats->rx_dropped++; 164 return ret; 165 } else { 166 /* 167 * note we could be going 168 * ingress -> egress or 169 * egress -> ingress 170 */ 171 skb->dev = skb->input_dev; 172 skb->input_dev = dev; 173 if (from & AT_INGRESS) { 174 skb_pull(skb, skb->dev->hard_header_len); 175 } else { 176 if (!(from & AT_EGRESS)) { 177 goto dropped; 178 } 179 } 180 } 181 182 if (skb_queue_len(&dp->rq) >= dev->tx_queue_len) { 183 netif_stop_queue(dev); 184 } 185 186 dev->trans_start = jiffies; 187 skb_queue_tail(&dp->rq, skb); 188 if (!dp->tasklet_pending) { 189 dp->tasklet_pending = 1; 190 tasklet_schedule(&dp->ifb_tasklet); 191 } 192 193 return ret; 194 } 195 196 static struct net_device_stats *ifb_get_stats(struct net_device *dev) 197 { 198 struct ifb_private *dp = netdev_priv(dev); 199 struct net_device_stats *stats = &dp->stats; 200 201 pr_debug("tasklets stats %ld:%ld:%ld:%ld:%ld:%ld:%ld:%ld:%ld \n", 202 dp->st_task_enter, dp->st_txq_refl_try, dp->st_rxq_enter, 203 dp->st_rx2tx_tran dp->st_rxq_notenter, dp->st_rx_frm_egr, 204 dp->st_rx_frm_ing, dp->st_rxq_check, dp->st_rxq_rsch ); 205 206 return stats; 207 } 208 209 static struct net_device **ifbs; 210 211 /* Number of ifb devices to be set up by this module. */ 212 module_param(numifbs, int, 0); 213 MODULE_PARM_DESC(numifbs, "Number of ifb devices"); 214 215 static int ifb_close(struct net_device *dev) 216 { 217 struct ifb_private *dp = netdev_priv(dev); 218 219 tasklet_kill(&dp->ifb_tasklet); 220 netif_stop_queue(dev); 221 skb_queue_purge(&dp->rq); 222 skb_queue_purge(&dp->tq); 223 return 0; 224 } 225 226 static int ifb_open(struct net_device *dev) 227 { 228 struct ifb_private *dp = netdev_priv(dev); 229 230 tasklet_init(&dp->ifb_tasklet, ri_tasklet, (unsigned long)dev); 231 skb_queue_head_init(&dp->rq); 232 skb_queue_head_init(&dp->tq); 233 netif_start_queue(dev); 234 235 return 0; 236 } 237 238 static int __init ifb_init_one(int index) 239 { 240 struct net_device *dev_ifb; 241 int err; 242 243 dev_ifb = alloc_netdev(sizeof(struct ifb_private), 244 "ifb%d", ifb_setup); 245 246 if (!dev_ifb) 247 return -ENOMEM; 248 249 if ((err = register_netdev(dev_ifb))) { 250 free_netdev(dev_ifb); 251 dev_ifb = NULL; 252 } else { 253 ifbs[index] = dev_ifb; 254 } 255 256 return err; 257 } 258 259 static void ifb_free_one(int index) 260 { 261 unregister_netdev(ifbs[index]); 262 free_netdev(ifbs[index]); 263 } 264 265 static int __init ifb_init_module(void) 266 { 267 int i, err = 0; 268 ifbs = kmalloc(numifbs * sizeof(void *), GFP_KERNEL); 269 if (!ifbs) 270 return -ENOMEM; 271 for (i = 0; i < numifbs && !err; i++) 272 err = ifb_init_one(i); 273 if (err) { 274 i--; 275 while (--i >= 0) 276 ifb_free_one(i); 277 } 278 279 return err; 280 } 281 282 static 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 } 290 291 module_init(ifb_init_module); 292 module_exit(ifb_cleanup_module); 293 MODULE_LICENSE("GPL"); 294 MODULE_AUTHOR("Jamal Hadi Salim"); 295