| 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"); |