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 sk_buff *skb; 73 74 dp->st_task_enter++; 75 if ((skb = skb_peek(&dp->tq)) == NULL) { 76 dp->st_txq_refl_try++; 77 if (netif_tx_trylock(_dev)) { 78 dp->st_rxq_enter++; 79 while ((skb = skb_dequeue(&dp->rq)) != NULL) { 80 skb_queue_tail(&dp->tq, skb); 81 dp->st_rx2tx_tran++; 82 } 83 netif_tx_unlock(_dev); 84 } else { 85 /* reschedule */ 86 dp->st_rxq_notenter++; 87 goto resched; 88 } 89 } 90 91 while ((skb = skb_dequeue(&dp->tq)) != NULL) { 92 u32 from = G_TC_FROM(skb->tc_verd); 93 94 skb->tc_verd = 0; 95 skb->tc_verd = SET_TC_NCLS(skb->tc_verd); 96 stats->tx_packets++; 97 stats->tx_bytes +=skb->len; 98 99 skb->dev = __dev_get_by_index(&init_net, skb->iif); 100 if (!skb->dev) { 101 dev_kfree_skb(skb); 102 stats->tx_dropped++; 103 break; 104 } 105 skb->iif = _dev->ifindex; 106 107 if (from & AT_EGRESS) { 108 dp->st_rx_frm_egr++; 109 dev_queue_xmit(skb); 110 } else if (from & AT_INGRESS) { 111 dp->st_rx_frm_ing++; 112 skb_pull(skb, skb->dev->hard_header_len); 113 netif_rx(skb); 114 } else 115 BUG(); 116 } 117 118 if (netif_tx_trylock(_dev)) { 119 dp->st_rxq_check++; 120 if ((skb = skb_peek(&dp->rq)) == NULL) { 121 dp->tasklet_pending = 0; 122 if (netif_queue_stopped(_dev)) 123 netif_wake_queue(_dev); 124 } else { 125 dp->st_rxq_rsch++; 126 netif_tx_unlock(_dev); 127 goto resched; 128 } 129 netif_tx_unlock(_dev); 130 } else { 131 resched: 132 dp->tasklet_pending = 1; 133 tasklet_schedule(&dp->ifb_tasklet); 134 } 135 136 } 137 138 static void ifb_setup(struct net_device *dev) 139 { 140 /* Initialize the device structure. */ 141 dev->hard_start_xmit = ifb_xmit; 142 dev->open = &ifb_open; 143 dev->stop = &ifb_close; 144 dev->destructor = free_netdev; 145 146 /* Fill in device structure with ethernet-generic values. */ 147 ether_setup(dev); 148 dev->tx_queue_len = TX_Q_LIMIT; 149 dev->change_mtu = NULL; 150 dev->flags |= IFF_NOARP; 151 dev->flags &= ~IFF_MULTICAST; 152 random_ether_addr(dev->dev_addr); 153 } 154 155 static int ifb_xmit(struct sk_buff *skb, struct net_device *dev) 156 { 157 struct ifb_private *dp = netdev_priv(dev); 158 struct net_device_stats *stats = &dev->stats; 159 int ret = 0; 160 u32 from = G_TC_FROM(skb->tc_verd); 161 162 stats->rx_packets++; 163 stats->rx_bytes+=skb->len; 164 165 if (!(from & (AT_INGRESS|AT_EGRESS)) || !skb->iif) { 166 dev_kfree_skb(skb); 167 stats->rx_dropped++; 168 return ret; 169 } 170 171 if (skb_queue_len(&dp->rq) >= dev->tx_queue_len) { 172 netif_stop_queue(dev); 173 } 174 175 dev->trans_start = jiffies; 176 skb_queue_tail(&dp->rq, skb); 177 if (!dp->tasklet_pending) { 178 dp->tasklet_pending = 1; 179 tasklet_schedule(&dp->ifb_tasklet); 180 } 181 182 return ret; 183 } 184 185 static int ifb_close(struct net_device *dev) 186 { 187 struct ifb_private *dp = netdev_priv(dev); 188 189 tasklet_kill(&dp->ifb_tasklet); 190 netif_stop_queue(dev); 191 skb_queue_purge(&dp->rq); 192 skb_queue_purge(&dp->tq); 193 return 0; 194 } 195 196 static int ifb_open(struct net_device *dev) 197 { 198 struct ifb_private *dp = netdev_priv(dev); 199 200 tasklet_init(&dp->ifb_tasklet, ri_tasklet, (unsigned long)dev); 201 skb_queue_head_init(&dp->rq); 202 skb_queue_head_init(&dp->tq); 203 netif_start_queue(dev); 204 205 return 0; 206 } 207 208 static int ifb_validate(struct nlattr *tb[], struct nlattr *data[]) 209 { 210 if (tb[IFLA_ADDRESS]) { 211 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN) 212 return -EINVAL; 213 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS]))) 214 return -EADDRNOTAVAIL; 215 } 216 return 0; 217 } 218 219 static struct rtnl_link_ops ifb_link_ops __read_mostly = { 220 .kind = "ifb", 221 .priv_size = sizeof(struct ifb_private), 222 .setup = ifb_setup, 223 .validate = ifb_validate, 224 }; 225 226 /* Number of ifb devices to be set up by this module. */ 227 module_param(numifbs, int, 0); 228 MODULE_PARM_DESC(numifbs, "Number of ifb devices"); 229 230 static int __init ifb_init_one(int index) 231 { 232 struct net_device *dev_ifb; 233 int err; 234 235 dev_ifb = alloc_netdev(sizeof(struct ifb_private), 236 "ifb%d", ifb_setup); 237 238 if (!dev_ifb) 239 return -ENOMEM; 240 241 err = dev_alloc_name(dev_ifb, dev_ifb->name); 242 if (err < 0) 243 goto err; 244 245 dev_ifb->rtnl_link_ops = &ifb_link_ops; 246 err = register_netdevice(dev_ifb); 247 if (err < 0) 248 goto err; 249 250 return 0; 251 252 err: 253 free_netdev(dev_ifb); 254 return err; 255 } 256 257 static int __init ifb_init_module(void) 258 { 259 int i, err; 260 261 rtnl_lock(); 262 err = __rtnl_link_register(&ifb_link_ops); 263 264 for (i = 0; i < numifbs && !err; i++) 265 err = ifb_init_one(i); 266 if (err) 267 __rtnl_link_unregister(&ifb_link_ops); 268 rtnl_unlock(); 269 270 return err; 271 } 272 273 static void __exit ifb_cleanup_module(void) 274 { 275 rtnl_link_unregister(&ifb_link_ops); 276 } 277 278 module_init(ifb_init_module); 279 module_exit(ifb_cleanup_module); 280 MODULE_LICENSE("GPL"); 281 MODULE_AUTHOR("Jamal Hadi Salim"); 282 MODULE_ALIAS_RTNL_LINK("ifb"); 283