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