diff options
Diffstat (limited to 'net/sched/sch_teql.c')
| -rw-r--r-- | net/sched/sch_teql.c | 538 |
1 files changed, 538 insertions, 0 deletions
diff --git a/net/sched/sch_teql.c b/net/sched/sch_teql.c new file mode 100644 index 00000000..45326599 --- /dev/null +++ b/net/sched/sch_teql.c @@ -0,0 +1,538 @@ +/* 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 <linux/types.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/string.h> +#include <linux/errno.h> +#include <linux/if_arp.h> +#include <linux/netdevice.h> +#include <linux/init.h> +#include <linux/skbuff.h> +#include <linux/moduleparam.h> +#include <net/dst.h> +#include <net/neighbour.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; + unsigned long tx_bytes; + unsigned long tx_packets; + unsigned long tx_errors; + unsigned long tx_dropped; +}; + +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) + +/* "teql*" qdisc routines */ + +static int +teql_enqueue(struct sk_buff *skb, struct Qdisc *sch) +{ + struct net_device *dev = qdisc_dev(sch); + struct teql_sched_data *q = qdisc_priv(sch); + + if (q->q.qlen < dev->tx_queue_len) { + __skb_queue_tail(&q->q, skb); + return NET_XMIT_SUCCESS; + } + + kfree_skb(skb); + sch->qstats.drops++; + return NET_XMIT_DROP; +} + +static struct sk_buff * +teql_dequeue(struct Qdisc *sch) +{ + struct teql_sched_data *dat = qdisc_priv(sch); + struct netdev_queue *dat_queue; + struct sk_buff *skb; + + skb = __skb_dequeue(&dat->q); + dat_queue = netdev_get_tx_queue(dat->m->dev, 0); + if (skb == NULL) { + struct net_device *m = qdisc_dev(dat_queue->qdisc); + if (m) { + dat->m->slaves = sch; + netif_wake_queue(m); + } + } else { + qdisc_bstats_update(sch, skb); + } + sch->q.qlen = dat->q.qlen + dat_queue->qdisc->q.qlen; + return skb; +} + +static struct sk_buff * +teql_peek(struct Qdisc *sch) +{ + /* teql is meant to be used as root qdisc */ + return NULL; +} + +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; + + prev = master->slaves; + if (prev) { + 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) { + struct netdev_queue *txq; + spinlock_t *root_lock; + + txq = netdev_get_tx_queue(master->dev, 0); + master->slaves = NULL; + + root_lock = qdisc_root_sleeping_lock(txq->qdisc); + spin_lock_bh(root_lock); + qdisc_reset(txq->qdisc); + spin_unlock_bh(root_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 nlattr *opt) +{ + struct net_device *dev = qdisc_dev(sch); + 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; +} + + +static int +__teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res, + struct net_device *dev, struct netdev_queue *txq, + struct neighbour *mn) +{ + struct teql_sched_data *q = qdisc_priv(txq->qdisc); + 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; + char haddr[MAX_ADDR_LEN]; + + neigh_ha_snapshot(haddr, n, dev); + err = dev_hard_header(skb, dev, ntohs(skb->protocol), haddr, + NULL, skb->len); + + 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, + struct netdev_queue *txq) +{ + struct dst_entry *dst = skb_dst(skb); + struct neighbour *mn; + int res; + + if (txq->qdisc == &noop_qdisc) + return -ENODEV; + + if (!dev->header_ops || !dst) + return 0; + + rcu_read_lock(); + mn = dst_get_neighbour_noref(dst); + res = mn ? __teql_resolve(skb, skb_res, dev, txq, mn) : 0; + rcu_read_unlock(); + + return res; +} + +static netdev_tx_t teql_master_xmit(struct sk_buff *skb, struct net_device *dev) +{ + struct teql_master *master = netdev_priv(dev); + struct Qdisc *start, *q; + int busy; + int nores; + int subq = skb_get_queue_mapping(skb); + struct sk_buff *skb_res = NULL; + + start = master->slaves; + +restart: + nores = 0; + busy = 0; + + q = start; + if (!q) + goto drop; + + do { + struct net_device *slave = qdisc_dev(q); + struct netdev_queue *slave_txq = netdev_get_tx_queue(slave, 0); + const struct net_device_ops *slave_ops = slave->netdev_ops; + + if (slave_txq->qdisc_sleeping != q) + continue; + if (netif_xmit_stopped(netdev_get_tx_queue(slave, subq)) || + !netif_running(slave)) { + busy = 1; + continue; + } + + switch (teql_resolve(skb, skb_res, slave, slave_txq)) { + case 0: + if (__netif_tx_trylock(slave_txq)) { + unsigned int length = qdisc_pkt_len(skb); + + if (!netif_xmit_frozen_or_stopped(slave_txq) && + slave_ops->ndo_start_xmit(skb, slave) == NETDEV_TX_OK) { + txq_trans_update(slave_txq); + __netif_tx_unlock(slave_txq); + master->slaves = NEXT_SLAVE(q); + netif_wake_queue(dev); + master->tx_packets++; + master->tx_bytes += length; + return NETDEV_TX_OK; + } + __netif_tx_unlock(slave_txq); + } + if (netif_xmit_stopped(netdev_get_tx_queue(dev, 0))) + busy = 1; + break; + case 1: + master->slaves = NEXT_SLAVE(q); + return NETDEV_TX_OK; + default: + nores = 1; + break; + } + __skb_pull(skb, skb_network_offset(skb)); + } while ((q = NEXT_SLAVE(q)) != start); + + if (nores && skb_res == NULL) { + skb_res = skb; + goto restart; + } + + if (busy) { + netif_stop_queue(dev); + return NETDEV_TX_BUSY; + } + master->tx_errors++; + +drop: + master->tx_dropped++; + dev_kfree_skb(skb); + return NETDEV_TX_OK; +} + +static int teql_master_open(struct net_device *dev) +{ + struct Qdisc *q; + struct teql_master *m = netdev_priv(dev); + int mtu = 0xFFFE; + unsigned int flags = IFF_NOARP | IFF_MULTICAST; + + if (m->slaves == NULL) + return -EUNATCH; + + flags = FMASK; + + q = m->slaves; + do { + struct net_device *slave = qdisc_dev(q); + + 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 rtnl_link_stats64 *teql_master_stats64(struct net_device *dev, + struct rtnl_link_stats64 *stats) +{ + struct teql_master *m = netdev_priv(dev); + + stats->tx_packets = m->tx_packets; + stats->tx_bytes = m->tx_bytes; + stats->tx_errors = m->tx_errors; + stats->tx_dropped = m->tx_dropped; + return stats; +} + +static int teql_master_mtu(struct net_device *dev, int new_mtu) +{ + struct teql_master *m = netdev_priv(dev); + struct Qdisc *q; + + if (new_mtu < 68) + return -EINVAL; + + q = m->slaves; + if (q) { + do { + if (new_mtu > qdisc_dev(q)->mtu) + return -EINVAL; + } while ((q = NEXT_SLAVE(q)) != m->slaves); + } + + dev->mtu = new_mtu; + return 0; +} + +static const struct net_device_ops teql_netdev_ops = { + .ndo_open = teql_master_open, + .ndo_stop = teql_master_close, + .ndo_start_xmit = teql_master_xmit, + .ndo_get_stats64 = teql_master_stats64, + .ndo_change_mtu = teql_master_mtu, +}; + +static __init void teql_master_setup(struct net_device *dev) +{ + struct teql_master *master = netdev_priv(dev); + 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->peek = teql_peek; + ops->init = teql_qdisc_init; + ops->reset = teql_reset; + ops->destroy = teql_destroy; + ops->owner = THIS_MODULE; + + dev->netdev_ops = &teql_netdev_ops; + dev->type = ARPHRD_VOID; + dev->mtu = 1500; + dev->tx_queue_len = 100; + dev->flags = IFF_NOARP; + dev->hard_header_len = LL_MAX_HEADER; + dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; +} + +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 = netdev_priv(dev); + + 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"); |