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_XMIT_DST_RELEASE | IFF_TX_SKB_SHARING); 189 eth_hw_addr_random(dev); 190 } 191 192 static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev) 193 { 194 struct ifb_private *dp = netdev_priv(dev); 195 u32 from = G_TC_FROM(skb->tc_verd); 196 197 u64_stats_update_begin(&dp->rsync); 198 dp->rx_packets++; 199 dp->rx_bytes += skb->len; 200 u64_stats_update_end(&dp->rsync); 201 202 if (!(from & (AT_INGRESS|AT_EGRESS)) || !skb->skb_iif) { 203 dev_kfree_skb(skb); 204 dev->stats.rx_dropped++; 205 return NETDEV_TX_OK; 206 } 207 208 if (skb_queue_len(&dp->rq) >= dev->tx_queue_len) { 209 netif_stop_queue(dev); 210 } 211 212 __skb_queue_tail(&dp->rq, skb); 213 if (!dp->tasklet_pending) { 214 dp->tasklet_pending = 1; 215 tasklet_schedule(&dp->ifb_tasklet); 216 } 217 218 return NETDEV_TX_OK; 219 } 220 221 static int ifb_close(struct net_device *dev) 222 { 223 struct ifb_private *dp = netdev_priv(dev); 224 225 tasklet_kill(&dp->ifb_tasklet); 226 netif_stop_queue(dev); 227 __skb_queue_purge(&dp->rq); 228 __skb_queue_purge(&dp->tq); 229 return 0; 230 } 231 232 static int ifb_open(struct net_device *dev) 233 { 234 struct ifb_private *dp = netdev_priv(dev); 235 236 tasklet_init(&dp->ifb_tasklet, ri_tasklet, (unsigned long)dev); 237 __skb_queue_head_init(&dp->rq); 238 __skb_queue_head_init(&dp->tq); 239 netif_start_queue(dev); 240 241 return 0; 242 } 243 244 static int ifb_validate(struct nlattr *tb[], struct nlattr *data[]) 245 { 246 if (tb[IFLA_ADDRESS]) { 247 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN) 248 return -EINVAL; 249 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS]))) 250 return -EADDRNOTAVAIL; 251 } 252 return 0; 253 } 254 255 static struct rtnl_link_ops ifb_link_ops __read_mostly = { 256 .kind = "ifb", 257 .priv_size = sizeof(struct ifb_private), 258 .setup = ifb_setup, 259 .validate = ifb_validate, 260 }; 261 262 /* Number of ifb devices to be set up by this module. */ 263 module_param(numifbs, int, 0); 264 MODULE_PARM_DESC(numifbs, "Number of ifb devices"); 265 266 static int __init ifb_init_one(int index) 267 { 268 struct net_device *dev_ifb; 269 struct ifb_private *dp; 270 int err; 271 272 dev_ifb = alloc_netdev(sizeof(struct ifb_private), 273 "ifb%d", ifb_setup); 274 275 if (!dev_ifb) 276 return -ENOMEM; 277 278 dp = netdev_priv(dev_ifb); 279 u64_stats_init(&dp->rsync); 280 u64_stats_init(&dp->tsync); 281 282 dev_ifb->rtnl_link_ops = &ifb_link_ops; 283 err = register_netdevice(dev_ifb); 284 if (err < 0) 285 goto err; 286 287 return 0; 288 289 err: 290 free_netdev(dev_ifb); 291 return err; 292 } 293 294 static int __init ifb_init_module(void) 295 { 296 int i, err; 297 298 rtnl_lock(); 299 err = __rtnl_link_register(&ifb_link_ops); 300 if (err < 0) 301 goto out; 302 303 for (i = 0; i < numifbs && !err; i++) { 304 err = ifb_init_one(i); 305 cond_resched(); 306 } 307 if (err) 308 __rtnl_link_unregister(&ifb_link_ops); 309 310 out: 311 rtnl_unlock(); 312 313 return err; 314 } 315 316 static void __exit ifb_cleanup_module(void) 317 { 318 rtnl_link_unregister(&ifb_link_ops); 319 } 320 321 module_init(ifb_init_module); 322 module_exit(ifb_cleanup_module); 323 MODULE_LICENSE("GPL"); 324 MODULE_AUTHOR("Jamal Hadi Salim"); 325 MODULE_ALIAS_RTNL_LINK("ifb"); 326