diff options
Diffstat (limited to 'net/sched/sch_teql.c')
| -rw-r--r-- | net/sched/sch_teql.c | 511 |
1 files changed, 511 insertions, 0 deletions
diff --git a/net/sched/sch_teql.c b/net/sched/sch_teql.c new file mode 100644 index 000000000000..6cf0342706b5 --- /dev/null +++ b/net/sched/sch_teql.c @@ -0,0 +1,511 @@ +/* net/sched/sch_teql.c "True" (or "trivial") link equalizer. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> + */ + +#include <linux/module.h> +#include <asm/uaccess.h> +#include <asm/system.h> +#include <linux/bitops.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/string.h> +#include <linux/mm.h> +#include <linux/socket.h> +#include <linux/sockios.h> +#include <linux/in.h> +#include <linux/errno.h> +#include <linux/interrupt.h> +#include <linux/if_ether.h> +#include <linux/inet.h> +#include <linux/netdevice.h> +#include <linux/etherdevice.h> +#include <linux/notifier.h> +#include <linux/init.h> +#include <net/ip.h> +#include <net/route.h> +#include <linux/skbuff.h> +#include <linux/moduleparam.h> +#include <net/sock.h> +#include <net/pkt_sched.h> + +/* + How to setup it. + ---------------- + + After loading this module you will find a new device teqlN + and new qdisc with the same name. To join a slave to the equalizer + you should just set this qdisc on a device f.e. + + # tc qdisc add dev eth0 root teql0 + # tc qdisc add dev eth1 root teql0 + + That's all. Full PnP 8) + + Applicability. + -------------- + + 1. Slave devices MUST be active devices, i.e., they must raise the tbusy + signal and generate EOI events. If you want to equalize virtual devices + like tunnels, use a normal eql device. + 2. This device puts no limitations on physical slave characteristics + f.e. it will equalize 9600baud line and 100Mb ethernet perfectly :-) + Certainly, large difference in link speeds will make the resulting + eqalized link unusable, because of huge packet reordering. + I estimate an upper useful difference as ~10 times. + 3. If the slave requires address resolution, only protocols using + neighbour cache (IPv4/IPv6) will work over the equalized link. + Other protocols are still allowed to use the slave device directly, + which will not break load balancing, though native slave + traffic will have the highest priority. */ + +struct teql_master +{ + struct Qdisc_ops qops; + struct net_device *dev; + struct Qdisc *slaves; + struct list_head master_list; + struct net_device_stats stats; +}; + +struct teql_sched_data +{ + struct Qdisc *next; + struct teql_master *m; + struct neighbour *ncache; + struct sk_buff_head q; +}; + +#define NEXT_SLAVE(q) (((struct teql_sched_data*)qdisc_priv(q))->next) + +#define FMASK (IFF_BROADCAST|IFF_POINTOPOINT|IFF_BROADCAST) + +/* "teql*" qdisc routines */ + +static int +teql_enqueue(struct sk_buff *skb, struct Qdisc* sch) +{ + struct net_device *dev = sch->dev; + struct teql_sched_data *q = qdisc_priv(sch); + + __skb_queue_tail(&q->q, skb); + if (q->q.qlen <= dev->tx_queue_len) { + sch->bstats.bytes += skb->len; + sch->bstats.packets++; + return 0; + } + + __skb_unlink(skb, &q->q); + kfree_skb(skb); + sch->qstats.drops++; + return NET_XMIT_DROP; +} + +static int +teql_requeue(struct sk_buff *skb, struct Qdisc* sch) +{ + struct teql_sched_data *q = qdisc_priv(sch); + + __skb_queue_head(&q->q, skb); + sch->qstats.requeues++; + return 0; +} + +static struct sk_buff * +teql_dequeue(struct Qdisc* sch) +{ + struct teql_sched_data *dat = qdisc_priv(sch); + struct sk_buff *skb; + + skb = __skb_dequeue(&dat->q); + if (skb == NULL) { + struct net_device *m = dat->m->dev->qdisc->dev; + if (m) { + dat->m->slaves = sch; + netif_wake_queue(m); + } + } + sch->q.qlen = dat->q.qlen + dat->m->dev->qdisc->q.qlen; + return skb; +} + +static __inline__ void +teql_neigh_release(struct neighbour *n) +{ + if (n) + neigh_release(n); +} + +static void +teql_reset(struct Qdisc* sch) +{ + struct teql_sched_data *dat = qdisc_priv(sch); + + skb_queue_purge(&dat->q); + sch->q.qlen = 0; + teql_neigh_release(xchg(&dat->ncache, NULL)); +} + +static void +teql_destroy(struct Qdisc* sch) +{ + struct Qdisc *q, *prev; + struct teql_sched_data *dat = qdisc_priv(sch); + struct teql_master *master = dat->m; + + if ((prev = master->slaves) != NULL) { + do { + q = NEXT_SLAVE(prev); + if (q == sch) { + NEXT_SLAVE(prev) = NEXT_SLAVE(q); + if (q == master->slaves) { + master->slaves = NEXT_SLAVE(q); + if (q == master->slaves) { + master->slaves = NULL; + spin_lock_bh(&master->dev->queue_lock); + qdisc_reset(master->dev->qdisc); + spin_unlock_bh(&master->dev->queue_lock); + } + } + skb_queue_purge(&dat->q); + teql_neigh_release(xchg(&dat->ncache, NULL)); + break; + } + + } while ((prev = q) != master->slaves); + } +} + +static int teql_qdisc_init(struct Qdisc *sch, struct rtattr *opt) +{ + struct net_device *dev = sch->dev; + struct teql_master *m = (struct teql_master*)sch->ops; + struct teql_sched_data *q = qdisc_priv(sch); + + if (dev->hard_header_len > m->dev->hard_header_len) + return -EINVAL; + + if (m->dev == dev) + return -ELOOP; + + q->m = m; + + skb_queue_head_init(&q->q); + + if (m->slaves) { + if (m->dev->flags & IFF_UP) { + if ((m->dev->flags&IFF_POINTOPOINT && !(dev->flags&IFF_POINTOPOINT)) + || (m->dev->flags&IFF_BROADCAST && !(dev->flags&IFF_BROADCAST)) + || (m->dev->flags&IFF_MULTICAST && !(dev->flags&IFF_MULTICAST)) + || dev->mtu < m->dev->mtu) + return -EINVAL; + } else { + if (!(dev->flags&IFF_POINTOPOINT)) + m->dev->flags &= ~IFF_POINTOPOINT; + if (!(dev->flags&IFF_BROADCAST)) + m->dev->flags &= ~IFF_BROADCAST; + if (!(dev->flags&IFF_MULTICAST)) + m->dev->flags &= ~IFF_MULTICAST; + if (dev->mtu < m->dev->mtu) + m->dev->mtu = dev->mtu; + } + q->next = NEXT_SLAVE(m->slaves); + NEXT_SLAVE(m->slaves) = sch; + } else { + q->next = sch; + m->slaves = sch; + m->dev->mtu = dev->mtu; + m->dev->flags = (m->dev->flags&~FMASK)|(dev->flags&FMASK); + } + return 0; +} + +/* "teql*" netdevice routines */ + +static int +__teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res, struct net_device *dev) +{ + struct teql_sched_data *q = qdisc_priv(dev->qdisc); + struct neighbour *mn = skb->dst->neighbour; + struct neighbour *n = q->ncache; + + if (mn->tbl == NULL) + return -EINVAL; + if (n && n->tbl == mn->tbl && + memcmp(n->primary_key, mn->primary_key, mn->tbl->key_len) == 0) { + atomic_inc(&n->refcnt); + } else { + n = __neigh_lookup_errno(mn->tbl, mn->primary_key, dev); + if (IS_ERR(n)) + return PTR_ERR(n); + } + if (neigh_event_send(n, skb_res) == 0) { + int err; + read_lock(&n->lock); + err = dev->hard_header(skb, dev, ntohs(skb->protocol), n->ha, NULL, skb->len); + read_unlock(&n->lock); + if (err < 0) { + neigh_release(n); + return -EINVAL; + } + teql_neigh_release(xchg(&q->ncache, n)); + return 0; + } + neigh_release(n); + return (skb_res == NULL) ? -EAGAIN : 1; +} + +static __inline__ int +teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res, struct net_device *dev) +{ + if (dev->hard_header == NULL || + skb->dst == NULL || + skb->dst->neighbour == NULL) + return 0; + return __teql_resolve(skb, skb_res, dev); +} + +static int teql_master_xmit(struct sk_buff *skb, struct net_device *dev) +{ + struct teql_master *master = (void*)dev->priv; + struct Qdisc *start, *q; + int busy; + int nores; + int len = skb->len; + struct sk_buff *skb_res = NULL; + + start = master->slaves; + +restart: + nores = 0; + busy = 0; + + if ((q = start) == NULL) + goto drop; + + do { + struct net_device *slave = q->dev; + + if (slave->qdisc_sleeping != q) + continue; + if (netif_queue_stopped(slave) || ! netif_running(slave)) { + busy = 1; + continue; + } + + switch (teql_resolve(skb, skb_res, slave)) { + case 0: + if (spin_trylock(&slave->xmit_lock)) { + slave->xmit_lock_owner = smp_processor_id(); + if (!netif_queue_stopped(slave) && + slave->hard_start_xmit(skb, slave) == 0) { + slave->xmit_lock_owner = -1; + spin_unlock(&slave->xmit_lock); + master->slaves = NEXT_SLAVE(q); + netif_wake_queue(dev); + master->stats.tx_packets++; + master->stats.tx_bytes += len; + return 0; + } + slave->xmit_lock_owner = -1; + spin_unlock(&slave->xmit_lock); + } + if (netif_queue_stopped(dev)) + busy = 1; + break; + case 1: + master->slaves = NEXT_SLAVE(q); + return 0; + default: + nores = 1; + break; + } + __skb_pull(skb, skb->nh.raw - skb->data); + } while ((q = NEXT_SLAVE(q)) != start); + + if (nores && skb_res == NULL) { + skb_res = skb; + goto restart; + } + + if (busy) { + netif_stop_queue(dev); + return 1; + } + master->stats.tx_errors++; + +drop: + master->stats.tx_dropped++; + dev_kfree_skb(skb); + return 0; +} + +static int teql_master_open(struct net_device *dev) +{ + struct Qdisc * q; + struct teql_master *m = (void*)dev->priv; + int mtu = 0xFFFE; + unsigned flags = IFF_NOARP|IFF_MULTICAST; + + if (m->slaves == NULL) + return -EUNATCH; + + flags = FMASK; + + q = m->slaves; + do { + struct net_device *slave = q->dev; + + if (slave == NULL) + return -EUNATCH; + + if (slave->mtu < mtu) + mtu = slave->mtu; + if (slave->hard_header_len > LL_MAX_HEADER) + return -EINVAL; + + /* If all the slaves are BROADCAST, master is BROADCAST + If all the slaves are PtP, master is PtP + Otherwise, master is NBMA. + */ + if (!(slave->flags&IFF_POINTOPOINT)) + flags &= ~IFF_POINTOPOINT; + if (!(slave->flags&IFF_BROADCAST)) + flags &= ~IFF_BROADCAST; + if (!(slave->flags&IFF_MULTICAST)) + flags &= ~IFF_MULTICAST; + } while ((q = NEXT_SLAVE(q)) != m->slaves); + + m->dev->mtu = mtu; + m->dev->flags = (m->dev->flags&~FMASK) | flags; + netif_start_queue(m->dev); + return 0; +} + +static int teql_master_close(struct net_device *dev) +{ + netif_stop_queue(dev); + return 0; +} + +static struct net_device_stats *teql_master_stats(struct net_device *dev) +{ + struct teql_master *m = (void*)dev->priv; + return &m->stats; +} + +static int teql_master_mtu(struct net_device *dev, int new_mtu) +{ + struct teql_master *m = (void*)dev->priv; + struct Qdisc *q; + + if (new_mtu < 68) + return -EINVAL; + + q = m->slaves; + if (q) { + do { + if (new_mtu > q->dev->mtu) + return -EINVAL; + } while ((q=NEXT_SLAVE(q)) != m->slaves); + } + + dev->mtu = new_mtu; + return 0; +} + +static __init void teql_master_setup(struct net_device *dev) +{ + struct teql_master *master = dev->priv; + struct Qdisc_ops *ops = &master->qops; + + master->dev = dev; + ops->priv_size = sizeof(struct teql_sched_data); + + ops->enqueue = teql_enqueue; + ops->dequeue = teql_dequeue; + ops->requeue = teql_requeue; + ops->init = teql_qdisc_init; + ops->reset = teql_reset; + ops->destroy = teql_destroy; + ops->owner = THIS_MODULE; + + dev->open = teql_master_open; + dev->hard_start_xmit = teql_master_xmit; + dev->stop = teql_master_close; + dev->get_stats = teql_master_stats; + dev->change_mtu = teql_master_mtu; + dev->type = ARPHRD_VOID; + dev->mtu = 1500; + dev->tx_queue_len = 100; + dev->flags = IFF_NOARP; + dev->hard_header_len = LL_MAX_HEADER; + SET_MODULE_OWNER(dev); +} + +static LIST_HEAD(master_dev_list); +static int max_equalizers = 1; +module_param(max_equalizers, int, 0); +MODULE_PARM_DESC(max_equalizers, "Max number of link equalizers"); + +static int __init teql_init(void) +{ + int i; + int err = -ENODEV; + + for (i = 0; i < max_equalizers; i++) { + struct net_device *dev; + struct teql_master *master; + + dev = alloc_netdev(sizeof(struct teql_master), + "teql%d", teql_master_setup); + if (!dev) { + err = -ENOMEM; + break; + } + + if ((err = register_netdev(dev))) { + free_netdev(dev); + break; + } + + master = dev->priv; + + strlcpy(master->qops.id, dev->name, IFNAMSIZ); + err = register_qdisc(&master->qops); + + if (err) { + unregister_netdev(dev); + free_netdev(dev); + break; + } + + list_add_tail(&master->master_list, &master_dev_list); + } + return i ? 0 : err; +} + +static void __exit teql_exit(void) +{ + struct teql_master *master, *nxt; + + list_for_each_entry_safe(master, nxt, &master_dev_list, master_list) { + + list_del(&master->master_list); + + unregister_qdisc(&master->qops); + unregister_netdev(master->dev); + free_netdev(master->dev); + } +} + +module_init(teql_init); +module_exit(teql_exit); + +MODULE_LICENSE("GPL"); |