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(&init_net, 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_bh(&dp->rsync); 140 stats->rx_packets = dp->rx_packets; 141 stats->rx_bytes = dp->rx_bytes; 142 } while (u64_stats_fetch_retry_bh(&dp->rsync, start)); 143 144 do { 145 start = u64_stats_fetch_begin_bh(&dp->tsync); 146 147 stats->tx_packets = dp->tx_packets; 148 stats->tx_bytes = dp->tx_bytes; 149 150 } while (u64_stats_fetch_retry_bh(&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_NO_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_TX) 170 171 static void ifb_setup(struct net_device *dev) 172 { 173 /* Initialize the device structure. */ 174 dev->destructor = free_netdev; 175 dev->netdev_ops = &ifb_netdev_ops; 176 177 /* Fill in device structure with ethernet-generic values. */ 178 ether_setup(dev); 179 dev->tx_queue_len = TX_Q_LIMIT; 180 181 dev->features |= IFB_FEATURES; 182 dev->vlan_features |= IFB_FEATURES; 183 184 dev->flags |= IFF_NOARP; 185 dev->flags &= ~IFF_MULTICAST; 186 dev->priv_flags &= ~(IFF_XMIT_DST_RELEASE | IFF_TX_SKB_SHARING); 187 random_ether_addr(dev->dev_addr); 188 } 189 190 static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev) 191 { 192 struct ifb_private *dp = netdev_priv(dev); 193 u32 from = G_TC_FROM(skb->tc_verd); 194 195 u64_stats_update_begin(&dp->rsync); 196 dp->rx_packets++; 197 dp->rx_bytes += skb->len; 198 u64_stats_update_end(&dp->rsync); 199 200 if (!(from & (AT_INGRESS|AT_EGRESS)) || !skb->skb_iif) { 201 dev_kfree_skb(skb); 202 dev->stats.rx_dropped++; 203 return NETDEV_TX_OK; 204 } 205 206 if (skb_queue_len(&dp->rq) >= dev->tx_queue_len) { 207 netif_stop_queue(dev); 208 } 209 210 __skb_queue_tail(&dp->rq, skb); 211 if (!dp->tasklet_pending) { 212 dp->tasklet_pending = 1; 213 tasklet_schedule(&dp->ifb_tasklet); 214 } 215 216 return NETDEV_TX_OK; 217 } 218 219 static int ifb_close(struct net_device *dev) 220 { 221 struct ifb_private *dp = netdev_priv(dev); 222 223 tasklet_kill(&dp->ifb_tasklet); 224 netif_stop_queue(dev); 225 __skb_queue_purge(&dp->rq); 226 __skb_queue_purge(&dp->tq); 227 return 0; 228 } 229 230 static int ifb_open(struct net_device *dev) 231 { 232 struct ifb_private *dp = netdev_priv(dev); 233 234 tasklet_init(&dp->ifb_tasklet, ri_tasklet, (unsigned long)dev); 235 __skb_queue_head_init(&dp->rq); 236 __skb_queue_head_init(&dp->tq); 237 netif_start_queue(dev); 238 239 return 0; 240 } 241 242 static int ifb_validate(struct nlattr *tb[], struct nlattr *data[]) 243 { 244 if (tb[IFLA_ADDRESS]) { 245 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN) 246 return -EINVAL; 247 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS]))) 248 return -EADDRNOTAVAIL; 249 } 250 return 0; 251 } 252 253 static struct rtnl_link_ops ifb_link_ops __read_mostly = { 254 .kind = "ifb", 255 .priv_size = sizeof(struct ifb_private), 256 .setup = ifb_setup, 257 .validate = ifb_validate, 258 }; 259 260 /* Number of ifb devices to be set up by this module. */ 261 module_param(numifbs, int, 0); 262 MODULE_PARM_DESC(numifbs, "Number of ifb devices"); 263 264 static int __init ifb_init_one(int index) 265 { 266 struct net_device *dev_ifb; 267 int err; 268 269 dev_ifb = alloc_netdev(sizeof(struct ifb_private), 270 "ifb%d", ifb_setup); 271 272 if (!dev_ifb) 273 return -ENOMEM; 274 275 dev_ifb->rtnl_link_ops = &ifb_link_ops; 276 err = register_netdevice(dev_ifb); 277 if (err < 0) 278 goto err; 279 280 return 0; 281 282 err: 283 free_netdev(dev_ifb); 284 return err; 285 } 286 287 static int __init ifb_init_module(void) 288 { 289 int i, err; 290 291 rtnl_lock(); 292 err = __rtnl_link_register(&ifb_link_ops); 293 294 for (i = 0; i < numifbs && !err; i++) 295 err = ifb_init_one(i); 296 if (err) 297 __rtnl_link_unregister(&ifb_link_ops); 298 rtnl_unlock(); 299 300 return err; 301 } 302 303 static void __exit ifb_cleanup_module(void) 304 { 305 rtnl_link_unregister(&ifb_link_ops); 306 } 307 308 module_init(ifb_init_module); 309 module_exit(ifb_cleanup_module); 310 MODULE_LICENSE("GPL"); 311 MODULE_AUTHOR("Jamal Hadi Salim"); 312 MODULE_ALIAS_RTNL_LINK("ifb"); 313