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 #include <net/net_namespace.h> 38 39 #define TX_TIMEOUT (2*HZ) 40 41 #define TX_Q_LIMIT 32 42 struct ifb_private { 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 int ifb_open(struct net_device *dev); 64 static int ifb_close(struct net_device *dev); 65 66 static void ri_tasklet(unsigned long dev) 67 { 68 69 struct net_device *_dev = (struct net_device *)dev; 70 struct ifb_private *dp = netdev_priv(_dev); 71 struct net_device_stats *stats = &_dev->stats; 72 struct netdev_queue *txq; 73 struct sk_buff *skb; 74 75 txq = netdev_get_tx_queue(_dev, 0); 76 dp->st_task_enter++; 77 if ((skb = skb_peek(&dp->tq)) == NULL) { 78 dp->st_txq_refl_try++; 79 if (__netif_tx_trylock(txq)) { 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 __netif_tx_unlock(txq); 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; 100 101 skb->dev = __dev_get_by_index(&init_net, skb->iif); 102 if (!skb->dev) { 103 dev_kfree_skb(skb); 104 stats->tx_dropped++; 105 break; 106 } 107 skb->iif = _dev->ifindex; 108 109 if (from & AT_EGRESS) { 110 dp->st_rx_frm_egr++; 111 dev_queue_xmit(skb); 112 } else if (from & AT_INGRESS) { 113 dp->st_rx_frm_ing++; 114 skb_pull(skb, skb->dev->hard_header_len); 115 netif_rx(skb); 116 } else 117 BUG(); 118 } 119 120 if (__netif_tx_trylock(txq)) { 121 dp->st_rxq_check++; 122 if ((skb = skb_peek(&dp->rq)) == NULL) { 123 dp->tasklet_pending = 0; 124 if (netif_queue_stopped(_dev)) 125 netif_wake_queue(_dev); 126 } else { 127 dp->st_rxq_rsch++; 128 __netif_tx_unlock(txq); 129 goto resched; 130 } 131 __netif_tx_unlock(txq); 132 } else { 133 resched: 134 dp->tasklet_pending = 1; 135 tasklet_schedule(&dp->ifb_tasklet); 136 } 137 138 } 139 140 static void ifb_setup(struct net_device *dev) 141 { 142 /* Initialize the device structure. */ 143 dev->hard_start_xmit = ifb_xmit; 144 dev->open = &ifb_open; 145 dev->stop = &ifb_close; 146 dev->destructor = free_netdev; 147 148 /* Fill in device structure with ethernet-generic values. */ 149 ether_setup(dev); 150 dev->tx_queue_len = TX_Q_LIMIT; 151 dev->change_mtu = NULL; 152 dev->flags |= IFF_NOARP; 153 dev->flags &= ~IFF_MULTICAST; 154 random_ether_addr(dev->dev_addr); 155 } 156 157 static 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 = &dev->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 } 186 187 static int ifb_close(struct net_device *dev) 188 { 189 struct ifb_private *dp = netdev_priv(dev); 190 191 tasklet_kill(&dp->ifb_tasklet); 192 netif_stop_queue(dev); 193 skb_queue_purge(&dp->rq); 194 skb_queue_purge(&dp->tq); 195 return 0; 196 } 197 198 static int ifb_open(struct net_device *dev) 199 { 200 struct ifb_private *dp = netdev_priv(dev); 201 202 tasklet_init(&dp->ifb_tasklet, ri_tasklet, (unsigned long)dev); 203 skb_queue_head_init(&dp->rq); 204 skb_queue_head_init(&dp->tq); 205 netif_start_queue(dev); 206 207 return 0; 208 } 209 210 static int ifb_validate(struct nlattr *tb[], struct nlattr *data[]) 211 { 212 if (tb[IFLA_ADDRESS]) { 213 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN) 214 return -EINVAL; 215 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS]))) 216 return -EADDRNOTAVAIL; 217 } 218 return 0; 219 } 220 221 static struct rtnl_link_ops ifb_link_ops __read_mostly = { 222 .kind = "ifb", 223 .priv_size = sizeof(struct ifb_private), 224 .setup = ifb_setup, 225 .validate = ifb_validate, 226 }; 227 228 /* Number of ifb devices to be set up by this module. */ 229 module_param(numifbs, int, 0); 230 MODULE_PARM_DESC(numifbs, "Number of ifb devices"); 231 232 static int __init ifb_init_one(int index) 233 { 234 struct net_device *dev_ifb; 235 int err; 236 237 dev_ifb = alloc_netdev(sizeof(struct ifb_private), 238 "ifb%d", ifb_setup); 239 240 if (!dev_ifb) 241 return -ENOMEM; 242 243 err = dev_alloc_name(dev_ifb, dev_ifb->name); 244 if (err < 0) 245 goto err; 246 247 dev_ifb->rtnl_link_ops = &ifb_link_ops; 248 err = register_netdevice(dev_ifb); 249 if (err < 0) 250 goto err; 251 252 return 0; 253 254 err: 255 free_netdev(dev_ifb); 256 return err; 257 } 258 259 static int __init ifb_init_module(void) 260 { 261 int i, err; 262 263 rtnl_lock(); 264 err = __rtnl_link_register(&ifb_link_ops); 265 266 for (i = 0; i < numifbs && !err; i++) 267 err = ifb_init_one(i); 268 if (err) 269 __rtnl_link_unregister(&ifb_link_ops); 270 rtnl_unlock(); 271 272 return err; 273 } 274 275 static void __exit ifb_cleanup_module(void) 276 { 277 rtnl_link_unregister(&ifb_link_ops); 278 } 279 280 module_init(ifb_init_module); 281 module_exit(ifb_cleanup_module); 282 MODULE_LICENSE("GPL"); 283 MODULE_AUTHOR("Jamal Hadi Salim"); 284 MODULE_ALIAS_RTNL_LINK("ifb"); 285