123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528 |
- /* 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 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;
- }
- return qdisc_drop(skb, sch);
- }
- 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;
- struct Qdisc *q;
- skb = __skb_dequeue(&dat->q);
- dat_queue = netdev_get_tx_queue(dat->m->dev, 0);
- q = rcu_dereference_bh(dat_queue->qdisc);
- if (skb == NULL) {
- struct net_device *m = qdisc_dev(q);
- if (m) {
- dat->m->slaves = sch;
- netif_wake_queue(m);
- }
- } else {
- qdisc_bstats_update(sch, skb);
- }
- sch->q.qlen = dat->q.qlen + q->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 void
- teql_reset(struct Qdisc *sch)
- {
- struct teql_sched_data *dat = qdisc_priv(sch);
- skb_queue_purge(&dat->q);
- sch->q.qlen = 0;
- }
- 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(rtnl_dereference(txq->qdisc));
- spin_lock_bh(root_lock);
- qdisc_reset(rtnl_dereference(txq->qdisc));
- spin_unlock_bh(root_lock);
- }
- }
- skb_queue_purge(&dat->q);
- 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 dst_entry *dst)
- {
- struct neighbour *n;
- int err = 0;
- n = dst_neigh_lookup_skb(dst, skb);
- if (!n)
- return -ENOENT;
- if (dst->dev != dev) {
- struct neighbour *mn;
- mn = __neigh_lookup_errno(n->tbl, n->primary_key, dev);
- neigh_release(n);
- if (IS_ERR(mn))
- return PTR_ERR(mn);
- n = mn;
- }
- 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(tc_skb_protocol(skb)),
- haddr, NULL, skb->len);
- if (err < 0)
- err = -EINVAL;
- } else {
- err = (skb_res == NULL) ? -EAGAIN : 1;
- }
- neigh_release(n);
- return err;
- }
- 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);
- int res;
- if (rcu_access_pointer(txq->qdisc) == &noop_qdisc)
- return -ENODEV;
- if (!dev->header_ops || !dst)
- return 0;
- rcu_read_lock();
- res = __teql_resolve(skb, skb_res, dev, txq, dst);
- 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);
- 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) &&
- netdev_start_xmit(skb, slave, slave_txq, false) ==
- NETDEV_TX_OK) {
- __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;
- netif_keep_dst(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",
- NET_NAME_UNKNOWN, 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");
|