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 netdev_tx_t 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 dev_put(skb->dev); 108 skb->iif = _dev->ifindex; 109 110 if (from & AT_EGRESS) { 111 dp->st_rx_frm_egr++; 112 dev_queue_xmit(skb); 113 } else if (from & AT_INGRESS) { 114 dp->st_rx_frm_ing++; 115 skb_pull(skb, skb->dev->hard_header_len); 116 netif_rx(skb); 117 } else 118 BUG(); 119 } 120 121 if (__netif_tx_trylock(txq)) { 122 dp->st_rxq_check++; 123 if ((skb = skb_peek(&dp->rq)) == NULL) { 124 dp->tasklet_pending = 0; 125 if (netif_queue_stopped(_dev)) 126 netif_wake_queue(_dev); 127 } else { 128 dp->st_rxq_rsch++; 129 __netif_tx_unlock(txq); 130 goto resched; 131 } 132 __netif_tx_unlock(txq); 133 } else { 134 resched: 135 dp->tasklet_pending = 1; 136 tasklet_schedule(&dp->ifb_tasklet); 137 } 138 139 } 140 141 static const struct net_device_ops ifb_netdev_ops = { 142 .ndo_open = ifb_open, 143 .ndo_stop = ifb_close, 144 .ndo_start_xmit = ifb_xmit, 145 .ndo_validate_addr = eth_validate_addr, 146 }; 147 148 static void ifb_setup(struct net_device *dev) 149 { 150 /* Initialize the device structure. */ 151 dev->destructor = free_netdev; 152 dev->netdev_ops = &ifb_netdev_ops; 153 154 /* Fill in device structure with ethernet-generic values. */ 155 ether_setup(dev); 156 dev->tx_queue_len = TX_Q_LIMIT; 157 158 dev->flags |= IFF_NOARP; 159 dev->flags &= ~IFF_MULTICAST; 160 dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; 161 random_ether_addr(dev->dev_addr); 162 } 163 164 static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev) 165 { 166 struct ifb_private *dp = netdev_priv(dev); 167 struct net_device_stats *stats = &dev->stats; 168 u32 from = G_TC_FROM(skb->tc_verd); 169 170 stats->rx_packets++; 171 stats->rx_bytes+=skb->len; 172 173 if (!(from & (AT_INGRESS|AT_EGRESS)) || !skb->iif) { 174 dev_kfree_skb(skb); 175 stats->rx_dropped++; 176 return NETDEV_TX_OK; 177 } 178 179 if (skb_queue_len(&dp->rq) >= dev->tx_queue_len) { 180 netif_stop_queue(dev); 181 } 182 183 dev->trans_start = jiffies; 184 skb_queue_tail(&dp->rq, skb); 185 if (!dp->tasklet_pending) { 186 dp->tasklet_pending = 1; 187 tasklet_schedule(&dp->ifb_tasklet); 188 } 189 190 return NETDEV_TX_OK; 191 } 192 193 static int ifb_close(struct net_device *dev) 194 { 195 struct ifb_private *dp = netdev_priv(dev); 196 197 tasklet_kill(&dp->ifb_tasklet); 198 netif_stop_queue(dev); 199 skb_queue_purge(&dp->rq); 200 skb_queue_purge(&dp->tq); 201 return 0; 202 } 203 204 static int ifb_open(struct net_device *dev) 205 { 206 struct ifb_private *dp = netdev_priv(dev); 207 208 tasklet_init(&dp->ifb_tasklet, ri_tasklet, (unsigned long)dev); 209 skb_queue_head_init(&dp->rq); 210 skb_queue_head_init(&dp->tq); 211 netif_start_queue(dev); 212 213 return 0; 214 } 215 216 static int ifb_validate(struct nlattr *tb[], struct nlattr *data[]) 217 { 218 if (tb[IFLA_ADDRESS]) { 219 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN) 220 return -EINVAL; 221 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS]))) 222 return -EADDRNOTAVAIL; 223 } 224 return 0; 225 } 226 227 static struct rtnl_link_ops ifb_link_ops __read_mostly = { 228 .kind = "ifb", 229 .priv_size = sizeof(struct ifb_private), 230 .setup = ifb_setup, 231 .validate = ifb_validate, 232 }; 233 234 /* Number of ifb devices to be set up by this module. */ 235 module_param(numifbs, int, 0); 236 MODULE_PARM_DESC(numifbs, "Number of ifb devices"); 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 err = dev_alloc_name(dev_ifb, dev_ifb->name); 250 if (err < 0) 251 goto err; 252 253 dev_ifb->rtnl_link_ops = &ifb_link_ops; 254 err = register_netdevice(dev_ifb); 255 if (err < 0) 256 goto err; 257 258 return 0; 259 260 err: 261 free_netdev(dev_ifb); 262 return err; 263 } 264 265 static int __init ifb_init_module(void) 266 { 267 int i, err; 268 269 rtnl_lock(); 270 err = __rtnl_link_register(&ifb_link_ops); 271 272 for (i = 0; i < numifbs && !err; i++) 273 err = ifb_init_one(i); 274 if (err) 275 __rtnl_link_unregister(&ifb_link_ops); 276 rtnl_unlock(); 277 278 return err; 279 } 280 281 static void __exit ifb_cleanup_module(void) 282 { 283 rtnl_link_unregister(&ifb_link_ops); 284 } 285 286 module_init(ifb_init_module); 287 module_exit(ifb_cleanup_module); 288 MODULE_LICENSE("GPL"); 289 MODULE_AUTHOR("Jamal Hadi Salim"); 290 MODULE_ALIAS_RTNL_LINK("ifb"); 291