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_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_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; 184 185 dev->flags |= IFF_NOARP; 186 dev->flags &= ~IFF_MULTICAST; 187 dev->priv_flags &= ~(IFF_XMIT_DST_RELEASE | IFF_TX_SKB_SHARING); 188 eth_hw_addr_random(dev); 189 } 190 191 static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev) 192 { 193 struct ifb_private *dp = netdev_priv(dev); 194 u32 from = G_TC_FROM(skb->tc_verd); 195 196 u64_stats_update_begin(&dp->rsync); 197 dp->rx_packets++; 198 dp->rx_bytes += skb->len; 199 u64_stats_update_end(&dp->rsync); 200 201 if (!(from & (AT_INGRESS|AT_EGRESS)) || !skb->skb_iif) { 202 dev_kfree_skb(skb); 203 dev->stats.rx_dropped++; 204 return NETDEV_TX_OK; 205 } 206 207 if (skb_queue_len(&dp->rq) >= dev->tx_queue_len) { 208 netif_stop_queue(dev); 209 } 210 211 __skb_queue_tail(&dp->rq, skb); 212 if (!dp->tasklet_pending) { 213 dp->tasklet_pending = 1; 214 tasklet_schedule(&dp->ifb_tasklet); 215 } 216 217 return NETDEV_TX_OK; 218 } 219 220 static int ifb_close(struct net_device *dev) 221 { 222 struct ifb_private *dp = netdev_priv(dev); 223 224 tasklet_kill(&dp->ifb_tasklet); 225 netif_stop_queue(dev); 226 __skb_queue_purge(&dp->rq); 227 __skb_queue_purge(&dp->tq); 228 return 0; 229 } 230 231 static int ifb_open(struct net_device *dev) 232 { 233 struct ifb_private *dp = netdev_priv(dev); 234 235 tasklet_init(&dp->ifb_tasklet, ri_tasklet, (unsigned long)dev); 236 __skb_queue_head_init(&dp->rq); 237 __skb_queue_head_init(&dp->tq); 238 netif_start_queue(dev); 239 240 return 0; 241 } 242 243 static int ifb_validate(struct nlattr *tb[], struct nlattr *data[]) 244 { 245 if (tb[IFLA_ADDRESS]) { 246 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN) 247 return -EINVAL; 248 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS]))) 249 return -EADDRNOTAVAIL; 250 } 251 return 0; 252 } 253 254 static struct rtnl_link_ops ifb_link_ops __read_mostly = { 255 .kind = "ifb", 256 .priv_size = sizeof(struct ifb_private), 257 .setup = ifb_setup, 258 .validate = ifb_validate, 259 }; 260 261 /* Number of ifb devices to be set up by this module. */ 262 module_param(numifbs, int, 0); 263 MODULE_PARM_DESC(numifbs, "Number of ifb devices"); 264 265 static int __init ifb_init_one(int index) 266 { 267 struct net_device *dev_ifb; 268 int err; 269 270 dev_ifb = alloc_netdev(sizeof(struct ifb_private), 271 "ifb%d", ifb_setup); 272 273 if (!dev_ifb) 274 return -ENOMEM; 275 276 dev_ifb->rtnl_link_ops = &ifb_link_ops; 277 err = register_netdevice(dev_ifb); 278 if (err < 0) 279 goto err; 280 281 return 0; 282 283 err: 284 free_netdev(dev_ifb); 285 return err; 286 } 287 288 static int __init ifb_init_module(void) 289 { 290 int i, err; 291 292 rtnl_lock(); 293 err = __rtnl_link_register(&ifb_link_ops); 294 if (err < 0) 295 goto out; 296 297 for (i = 0; i < numifbs && !err; i++) { 298 err = ifb_init_one(i); 299 cond_resched(); 300 } 301 if (err) 302 __rtnl_link_unregister(&ifb_link_ops); 303 304 out: 305 rtnl_unlock(); 306 307 return err; 308 } 309 310 static void __exit ifb_cleanup_module(void) 311 { 312 rtnl_link_unregister(&ifb_link_ops); 313 } 314 315 module_init(ifb_init_module); 316 module_exit(ifb_cleanup_module); 317 MODULE_LICENSE("GPL"); 318 MODULE_AUTHOR("Jamal Hadi Salim"); 319 MODULE_ALIAS_RTNL_LINK("ifb"); 320