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/interrupt.h> 36 #include <linux/moduleparam.h> 37 #include <net/pkt_sched.h> 38 #include <net/net_namespace.h> 39 40 #define TX_Q_LIMIT 32 41 struct ifb_private { 42 struct tasklet_struct ifb_tasklet; 43 int tasklet_pending; 44 45 struct u64_stats_sync rsync; 46 struct sk_buff_head rq; 47 u64 rx_packets; 48 u64 rx_bytes; 49 50 struct u64_stats_sync tsync; 51 struct sk_buff_head tq; 52 u64 tx_packets; 53 u64 tx_bytes; 54 }; 55 56 static int numifbs = 2; 57 58 static void ri_tasklet(unsigned long dev); 59 static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev); 60 static int ifb_open(struct net_device *dev); 61 static int ifb_close(struct net_device *dev); 62 63 static void ri_tasklet(unsigned long dev) 64 { 65 struct net_device *_dev = (struct net_device *)dev; 66 struct ifb_private *dp = netdev_priv(_dev); 67 struct netdev_queue *txq; 68 struct sk_buff *skb; 69 70 txq = netdev_get_tx_queue(_dev, 0); 71 if ((skb = skb_peek(&dp->tq)) == NULL) { 72 if (__netif_tx_trylock(txq)) { 73 skb_queue_splice_tail_init(&dp->rq, &dp->tq); 74 __netif_tx_unlock(txq); 75 } else { 76 /* reschedule */ 77 goto resched; 78 } 79 } 80 81 while ((skb = __skb_dequeue(&dp->tq)) != NULL) { 82 u32 from = G_TC_FROM(skb->tc_verd); 83 84 skb->tc_verd = 0; 85 skb->tc_verd = SET_TC_NCLS(skb->tc_verd); 86 87 u64_stats_update_begin(&dp->tsync); 88 dp->tx_packets++; 89 dp->tx_bytes += skb->len; 90 u64_stats_update_end(&dp->tsync); 91 92 rcu_read_lock(); 93 skb->dev = dev_get_by_index_rcu(dev_net(_dev), skb->skb_iif); 94 if (!skb->dev) { 95 rcu_read_unlock(); 96 dev_kfree_skb(skb); 97 _dev->stats.tx_dropped++; 98 if (skb_queue_len(&dp->tq) != 0) 99 goto resched; 100 break; 101 } 102 rcu_read_unlock(); 103 skb->skb_iif = _dev->ifindex; 104 105 if (from & AT_EGRESS) { 106 dev_queue_xmit(skb); 107 } else if (from & AT_INGRESS) { 108 skb_pull(skb, skb->dev->hard_header_len); 109 netif_receive_skb(skb); 110 } else 111 BUG(); 112 } 113 114 if (__netif_tx_trylock(txq)) { 115 if ((skb = skb_peek(&dp->rq)) == NULL) { 116 dp->tasklet_pending = 0; 117 if (netif_queue_stopped(_dev)) 118 netif_wake_queue(_dev); 119 } else { 120 __netif_tx_unlock(txq); 121 goto resched; 122 } 123 __netif_tx_unlock(txq); 124 } else { 125 resched: 126 dp->tasklet_pending = 1; 127 tasklet_schedule(&dp->ifb_tasklet); 128 } 129 130 } 131 132 static struct rtnl_link_stats64 *ifb_stats64(struct net_device *dev, 133 struct rtnl_link_stats64 *stats) 134 { 135 struct ifb_private *dp = netdev_priv(dev); 136 unsigned int start; 137 138 do { 139 start = u64_stats_fetch_begin_irq(&dp->rsync); 140 stats->rx_packets = dp->rx_packets; 141 stats->rx_bytes = dp->rx_bytes; 142 } while (u64_stats_fetch_retry_irq(&dp->rsync, start)); 143 144 do { 145 start = u64_stats_fetch_begin_irq(&dp->tsync); 146 147 stats->tx_packets = dp->tx_packets; 148 stats->tx_bytes = dp->tx_bytes; 149 150 } while (u64_stats_fetch_retry_irq(&dp->tsync, start)); 151 152 stats->rx_dropped = dev->stats.rx_dropped; 153 stats->tx_dropped = dev->stats.tx_dropped; 154 155 return stats; 156 } 157 158 159 static const struct net_device_ops ifb_netdev_ops = { 160 .ndo_open = ifb_open, 161 .ndo_stop = ifb_close, 162 .ndo_get_stats64 = ifb_stats64, 163 .ndo_start_xmit = ifb_xmit, 164 .ndo_validate_addr = eth_validate_addr, 165 }; 166 167 #define IFB_FEATURES (NETIF_F_HW_CSUM | NETIF_F_SG | NETIF_F_FRAGLIST | \ 168 NETIF_F_TSO_ECN | NETIF_F_TSO | NETIF_F_TSO6 | \ 169 NETIF_F_HIGHDMA | NETIF_F_HW_VLAN_CTAG_TX | \ 170 NETIF_F_HW_VLAN_STAG_TX) 171 172 static void ifb_setup(struct net_device *dev) 173 { 174 /* Initialize the device structure. */ 175 dev->destructor = free_netdev; 176 dev->netdev_ops = &ifb_netdev_ops; 177 178 /* Fill in device structure with ethernet-generic values. */ 179 ether_setup(dev); 180 dev->tx_queue_len = TX_Q_LIMIT; 181 182 dev->features |= IFB_FEATURES; 183 dev->vlan_features |= IFB_FEATURES & ~(NETIF_F_HW_VLAN_CTAG_TX | 184 NETIF_F_HW_VLAN_STAG_TX); 185 186 dev->flags |= IFF_NOARP; 187 dev->flags &= ~IFF_MULTICAST; 188 dev->priv_flags &= ~IFF_TX_SKB_SHARING; 189 netif_keep_dst(dev); 190 eth_hw_addr_random(dev); 191 } 192 193 static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev) 194 { 195 struct ifb_private *dp = netdev_priv(dev); 196 u32 from = G_TC_FROM(skb->tc_verd); 197 198 u64_stats_update_begin(&dp->rsync); 199 dp->rx_packets++; 200 dp->rx_bytes += skb->len; 201 u64_stats_update_end(&dp->rsync); 202 203 if (!(from & (AT_INGRESS|AT_EGRESS)) || !skb->skb_iif) { 204 dev_kfree_skb(skb); 205 dev->stats.rx_dropped++; 206 return NETDEV_TX_OK; 207 } 208 209 if (skb_queue_len(&dp->rq) >= dev->tx_queue_len) { 210 netif_stop_queue(dev); 211 } 212 213 __skb_queue_tail(&dp->rq, skb); 214 if (!dp->tasklet_pending) { 215 dp->tasklet_pending = 1; 216 tasklet_schedule(&dp->ifb_tasklet); 217 } 218 219 return NETDEV_TX_OK; 220 } 221 222 static int ifb_close(struct net_device *dev) 223 { 224 struct ifb_private *dp = netdev_priv(dev); 225 226 tasklet_kill(&dp->ifb_tasklet); 227 netif_stop_queue(dev); 228 __skb_queue_purge(&dp->rq); 229 __skb_queue_purge(&dp->tq); 230 return 0; 231 } 232 233 static int ifb_open(struct net_device *dev) 234 { 235 struct ifb_private *dp = netdev_priv(dev); 236 237 tasklet_init(&dp->ifb_tasklet, ri_tasklet, (unsigned long)dev); 238 __skb_queue_head_init(&dp->rq); 239 __skb_queue_head_init(&dp->tq); 240 netif_start_queue(dev); 241 242 return 0; 243 } 244 245 static int ifb_validate(struct nlattr *tb[], struct nlattr *data[]) 246 { 247 if (tb[IFLA_ADDRESS]) { 248 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN) 249 return -EINVAL; 250 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS]))) 251 return -EADDRNOTAVAIL; 252 } 253 return 0; 254 } 255 256 static struct rtnl_link_ops ifb_link_ops __read_mostly = { 257 .kind = "ifb", 258 .priv_size = sizeof(struct ifb_private), 259 .setup = ifb_setup, 260 .validate = ifb_validate, 261 }; 262 263 /* Number of ifb devices to be set up by this module. */ 264 module_param(numifbs, int, 0); 265 MODULE_PARM_DESC(numifbs, "Number of ifb devices"); 266 267 static int __init ifb_init_one(int index) 268 { 269 struct net_device *dev_ifb; 270 struct ifb_private *dp; 271 int err; 272 273 dev_ifb = alloc_netdev(sizeof(struct ifb_private), "ifb%d", 274 NET_NAME_UNKNOWN, ifb_setup); 275 276 if (!dev_ifb) 277 return -ENOMEM; 278 279 dp = netdev_priv(dev_ifb); 280 u64_stats_init(&dp->rsync); 281 u64_stats_init(&dp->tsync); 282 283 dev_ifb->rtnl_link_ops = &ifb_link_ops; 284 err = register_netdevice(dev_ifb); 285 if (err < 0) 286 goto err; 287 288 return 0; 289 290 err: 291 free_netdev(dev_ifb); 292 return err; 293 } 294 295 static int __init ifb_init_module(void) 296 { 297 int i, err; 298 299 rtnl_lock(); 300 err = __rtnl_link_register(&ifb_link_ops); 301 if (err < 0) 302 goto out; 303 304 for (i = 0; i < numifbs && !err; i++) { 305 err = ifb_init_one(i); 306 cond_resched(); 307 } 308 if (err) 309 __rtnl_link_unregister(&ifb_link_ops); 310 311 out: 312 rtnl_unlock(); 313 314 return err; 315 } 316 317 static void __exit ifb_cleanup_module(void) 318 { 319 rtnl_link_unregister(&ifb_link_ops); 320 } 321 322 module_init(ifb_init_module); 323 module_exit(ifb_cleanup_module); 324 MODULE_LICENSE("GPL"); 325 MODULE_AUTHOR("Jamal Hadi Salim"); 326 MODULE_ALIAS_RTNL_LINK("ifb"); 327