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 41struct 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 59static int numifbs = 2; 60 61static void ri_tasklet(unsigned long dev); 62static int ifb_xmit(struct sk_buff *skb, struct net_device *dev); 63static struct net_device_stats *ifb_get_stats(struct net_device *dev); 64static int ifb_open(struct net_device *dev); 65static int ifb_close(struct net_device *dev); 66 67static 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; 99 100 skb->dev = __dev_get_by_index(skb->iif); 101 if (!skb->dev) { 102 dev_kfree_skb(skb); 103 stats->tx_dropped++; 104 break; 105 } 106 skb->iif = _dev->ifindex; 107 108 if (from & AT_EGRESS) { 109 dp->st_rx_frm_egr++; 110 dev_queue_xmit(skb); 111 } else if (from & AT_INGRESS) { 112 dp->st_rx_frm_ing++; 113 skb_pull(skb, skb->dev->hard_header_len); 114 netif_rx(skb); 115 } else 116 BUG(); 117 } 118 119 if (netif_tx_trylock(_dev)) { 120 dp->st_rxq_check++; 121 if ((skb = skb_peek(&dp->rq)) == NULL) { 122 dp->tasklet_pending = 0; 123 if (netif_queue_stopped(_dev)) 124 netif_wake_queue(_dev); 125 } else { 126 dp->st_rxq_rsch++; 127 netif_tx_unlock(_dev); 128 goto resched; 129 } 130 netif_tx_unlock(_dev); 131 } else { 132resched: 133 dp->tasklet_pending = 1; 134 tasklet_schedule(&dp->ifb_tasklet); 135 } 136 137} 138 139static void __init ifb_setup(struct net_device *dev) 140{ 141 /* Initialize the device structure. */ 142 dev->get_stats = ifb_get_stats; 143 dev->hard_start_xmit = ifb_xmit; 144 dev->open = &ifb_open; 145 dev->stop = &ifb_close; 146 147 /* Fill in device structure with ethernet-generic values. */ 148 ether_setup(dev); 149 dev->tx_queue_len = TX_Q_LIMIT; 150 dev->change_mtu = NULL; 151 dev->flags |= IFF_NOARP; 152 dev->flags &= ~IFF_MULTICAST; 153 SET_MODULE_OWNER(dev); 154 random_ether_addr(dev->dev_addr); 155} 156 157static int ifb_xmit(struct sk_buff *skb, struct net_device *dev) 158{ 159 struct ifb_private *dp = netdev_priv(dev); 160 struct net_device_stats *stats = &dp->stats; 161 int ret = 0; 162 u32 from = G_TC_FROM(skb->tc_verd); 163 164 stats->rx_packets++; 165 stats->rx_bytes+=skb->len; 166 167 if (!(from & (AT_INGRESS|AT_EGRESS)) || !skb->iif) { 168 dev_kfree_skb(skb); 169 stats->rx_dropped++; 170 return ret; 171 } 172 173 if (skb_queue_len(&dp->rq) >= dev->tx_queue_len) { 174 netif_stop_queue(dev); 175 } 176 177 dev->trans_start = jiffies; 178 skb_queue_tail(&dp->rq, skb); 179 if (!dp->tasklet_pending) { 180 dp->tasklet_pending = 1; 181 tasklet_schedule(&dp->ifb_tasklet); 182 } 183 184 return ret; 185} 186 187static struct net_device_stats *ifb_get_stats(struct net_device *dev) 188{ 189 struct ifb_private *dp = netdev_priv(dev); 190 struct net_device_stats *stats = &dp->stats; 191 192 pr_debug("tasklets stats %ld:%ld:%ld:%ld:%ld:%ld:%ld:%ld:%ld \n", 193 dp->st_task_enter, dp->st_txq_refl_try, dp->st_rxq_enter, 194 dp->st_rx2tx_tran, dp->st_rxq_notenter, dp->st_rx_frm_egr, 195 dp->st_rx_frm_ing, dp->st_rxq_check, dp->st_rxq_rsch); 196 197 return stats; 198} 199 200static struct net_device **ifbs; 201 202/* Number of ifb devices to be set up by this module. */ 203module_param(numifbs, int, 0); 204MODULE_PARM_DESC(numifbs, "Number of ifb devices"); 205 206static int ifb_close(struct net_device *dev) 207{ 208 struct ifb_private *dp = netdev_priv(dev); 209 210 tasklet_kill(&dp->ifb_tasklet); 211 netif_stop_queue(dev); 212 skb_queue_purge(&dp->rq); 213 skb_queue_purge(&dp->tq); 214 return 0; 215} 216 217static int ifb_open(struct net_device *dev) 218{ 219 struct ifb_private *dp = netdev_priv(dev); 220 221 tasklet_init(&dp->ifb_tasklet, ri_tasklet, (unsigned long)dev); 222 skb_queue_head_init(&dp->rq); 223 skb_queue_head_init(&dp->tq); 224 netif_start_queue(dev); 225 226 return 0; 227} 228 229static int __init ifb_init_one(int index) 230{ 231 struct net_device *dev_ifb; 232 int err; 233 234 dev_ifb = alloc_netdev(sizeof(struct ifb_private), 235 "ifb%d", ifb_setup); 236 237 if (!dev_ifb) 238 return -ENOMEM; 239 240 if ((err = register_netdev(dev_ifb))) { 241 free_netdev(dev_ifb); 242 dev_ifb = NULL; 243 } else { 244 ifbs[index] = dev_ifb; 245 } 246 247 return err; 248} 249 250static void ifb_free_one(int index) 251{ 252 unregister_netdev(ifbs[index]); 253 free_netdev(ifbs[index]); 254} 255 256static int __init ifb_init_module(void) 257{ 258 int i, err = 0; 259 ifbs = kmalloc(numifbs * sizeof(void *), GFP_KERNEL); 260 if (!ifbs) 261 return -ENOMEM; 262 for (i = 0; i < numifbs && !err; i++) 263 err = ifb_init_one(i); 264 if (err) { 265 i--; 266 while (--i >= 0) 267 ifb_free_one(i); 268 } 269 270 return err; 271} 272 273static void __exit ifb_cleanup_module(void) 274{ 275 int i; 276 277 for (i = 0; i < numifbs; i++) 278 ifb_free_one(i); 279 kfree(ifbs); 280} 281 282module_init(ifb_init_module); 283module_exit(ifb_cleanup_module); 284MODULE_LICENSE("GPL"); 285MODULE_AUTHOR("Jamal Hadi Salim"); 286