1 files changed, 458 insertions, 0 deletions

diff --git a/drivers/net/ifb.c b/drivers/net/ifb.c
new file mode 100644
index 000000000..1c64d5347
--- /dev/null
+++ b/drivers/net/ifb.c
@@ -0,0 +1,458 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* drivers/net/ifb.c:
+
+	The purpose of this driver is to provide a device that allows
+	for sharing of resources:
+
+	1) qdiscs/policies that are per device as opposed to system wide.
+	ifb allows for a device which can be redirected to thus providing
+	an impression of sharing.
+
+	2) Allows for queueing incoming traffic for shaping instead of
+	dropping.
+
+	The original concept is based on what is known as the IMQ
+	driver initially written by Martin Devera, later rewritten
+	by Patrick McHardy and then maintained by Andre Correa.
+
+	You need the tc action  mirror or redirect to feed this device
+	packets.
+
+
+	Authors:	Jamal Hadi Salim (2005)
+
+*/
+
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/netdevice.h>
+#include <linux/ethtool.h>
+#include <linux/etherdevice.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/moduleparam.h>
+#include <linux/netfilter_netdev.h>
+#include <net/pkt_sched.h>
+#include <net/net_namespace.h>
+
+#define TX_Q_LIMIT    32
+
+struct ifb_q_stats {
+	u64 packets;
+	u64 bytes;
+	struct u64_stats_sync	sync;
+};
+
+struct ifb_q_private {
+	struct net_device	*dev;
+	struct tasklet_struct   ifb_tasklet;
+	int			tasklet_pending;
+	int			txqnum;
+	struct sk_buff_head     rq;
+	struct sk_buff_head     tq;
+	struct ifb_q_stats	rx_stats;
+	struct ifb_q_stats	tx_stats;
+} ____cacheline_aligned_in_smp;
+
+struct ifb_dev_private {
+	struct ifb_q_private *tx_private;
+};
+
+/* For ethtools stats. */
+struct ifb_q_stats_desc {
+	char	desc[ETH_GSTRING_LEN];
+	size_t	offset;
+};
+
+#define IFB_Q_STAT(m)	offsetof(struct ifb_q_stats, m)
+
+static const struct ifb_q_stats_desc ifb_q_stats_desc[] = {
+	{ "packets",	IFB_Q_STAT(packets) },
+	{ "bytes",	IFB_Q_STAT(bytes) },
+};
+
+#define IFB_Q_STATS_LEN	ARRAY_SIZE(ifb_q_stats_desc)
+
+static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev);
+static int ifb_open(struct net_device *dev);
+static int ifb_close(struct net_device *dev);
+
+static void ifb_update_q_stats(struct ifb_q_stats *stats, int len)
+{
+	u64_stats_update_begin(&stats->sync);
+	stats->packets++;
+	stats->bytes += len;
+	u64_stats_update_end(&stats->sync);
+}
+
+static void ifb_ri_tasklet(struct tasklet_struct *t)
+{
+	struct ifb_q_private *txp = from_tasklet(txp, t, ifb_tasklet);
+	struct netdev_queue *txq;
+	struct sk_buff *skb;
+
+	txq = netdev_get_tx_queue(txp->dev, txp->txqnum);
+	skb = skb_peek(&txp->tq);
+	if (!skb) {
+		if (!__netif_tx_trylock(txq))
+			goto resched;
+		skb_queue_splice_tail_init(&txp->rq, &txp->tq);
+		__netif_tx_unlock(txq);
+	}
+
+	while ((skb = __skb_dequeue(&txp->tq)) != NULL) {
+		/* Skip tc and netfilter to prevent redirection loop. */
+		skb->redirected = 0;
+#ifdef CONFIG_NET_CLS_ACT
+		skb->tc_skip_classify = 1;
+#endif
+		nf_skip_egress(skb, true);
+
+		ifb_update_q_stats(&txp->tx_stats, skb->len);
+
+		rcu_read_lock();
+		skb->dev = dev_get_by_index_rcu(dev_net(txp->dev), skb->skb_iif);
+		if (!skb->dev) {
+			rcu_read_unlock();
+			dev_kfree_skb(skb);
+			txp->dev->stats.tx_dropped++;
+			if (skb_queue_len(&txp->tq) != 0)
+				goto resched;
+			break;
+		}
+		rcu_read_unlock();
+		skb->skb_iif = txp->dev->ifindex;
+
+		if (!skb->from_ingress) {
+			dev_queue_xmit(skb);
+		} else {
+			skb_pull_rcsum(skb, skb->mac_len);
+			netif_receive_skb(skb);
+		}
+	}
+
+	if (__netif_tx_trylock(txq)) {
+		skb = skb_peek(&txp->rq);
+		if (!skb) {
+			txp->tasklet_pending = 0;
+			if (netif_tx_queue_stopped(txq))
+				netif_tx_wake_queue(txq);
+		} else {
+			__netif_tx_unlock(txq);
+			goto resched;
+		}
+		__netif_tx_unlock(txq);
+	} else {
+resched:
+		txp->tasklet_pending = 1;
+		tasklet_schedule(&txp->ifb_tasklet);
+	}
+
+}
+
+static void ifb_stats64(struct net_device *dev,
+			struct rtnl_link_stats64 *stats)
+{
+	struct ifb_dev_private *dp = netdev_priv(dev);
+	struct ifb_q_private *txp = dp->tx_private;
+	unsigned int start;
+	u64 packets, bytes;
+	int i;
+
+	for (i = 0; i < dev->num_tx_queues; i++,txp++) {
+		do {
+			start = u64_stats_fetch_begin_irq(&txp->rx_stats.sync);
+			packets = txp->rx_stats.packets;
+			bytes = txp->rx_stats.bytes;
+		} while (u64_stats_fetch_retry_irq(&txp->rx_stats.sync, start));
+		stats->rx_packets += packets;
+		stats->rx_bytes += bytes;
+
+		do {
+			start = u64_stats_fetch_begin_irq(&txp->tx_stats.sync);
+			packets = txp->tx_stats.packets;
+			bytes = txp->tx_stats.bytes;
+		} while (u64_stats_fetch_retry_irq(&txp->tx_stats.sync, start));
+		stats->tx_packets += packets;
+		stats->tx_bytes += bytes;
+	}
+	stats->rx_dropped = dev->stats.rx_dropped;
+	stats->tx_dropped = dev->stats.tx_dropped;
+}
+
+static int ifb_dev_init(struct net_device *dev)
+{
+	struct ifb_dev_private *dp = netdev_priv(dev);
+	struct ifb_q_private *txp;
+	int i;
+
+	txp = kcalloc(dev->num_tx_queues, sizeof(*txp), GFP_KERNEL);
+	if (!txp)
+		return -ENOMEM;
+	dp->tx_private = txp;
+	for (i = 0; i < dev->num_tx_queues; i++,txp++) {
+		txp->txqnum = i;
+		txp->dev = dev;
+		__skb_queue_head_init(&txp->rq);
+		__skb_queue_head_init(&txp->tq);
+		u64_stats_init(&txp->rx_stats.sync);
+		u64_stats_init(&txp->tx_stats.sync);
+		tasklet_setup(&txp->ifb_tasklet, ifb_ri_tasklet);
+		netif_tx_start_queue(netdev_get_tx_queue(dev, i));
+	}
+	return 0;
+}
+
+static void ifb_get_strings(struct net_device *dev, u32 stringset, u8 *buf)
+{
+	u8 *p = buf;
+	int i, j;
+
+	switch (stringset) {
+	case ETH_SS_STATS:
+		for (i = 0; i < dev->real_num_rx_queues; i++)
+			for (j = 0; j < IFB_Q_STATS_LEN; j++)
+				ethtool_sprintf(&p, "rx_queue_%u_%.18s",
+						i, ifb_q_stats_desc[j].desc);
+
+		for (i = 0; i < dev->real_num_tx_queues; i++)
+			for (j = 0; j < IFB_Q_STATS_LEN; j++)
+				ethtool_sprintf(&p, "tx_queue_%u_%.18s",
+						i, ifb_q_stats_desc[j].desc);
+
+		break;
+	}
+}
+
+static int ifb_get_sset_count(struct net_device *dev, int sset)
+{
+	switch (sset) {
+	case ETH_SS_STATS:
+		return IFB_Q_STATS_LEN * (dev->real_num_rx_queues +
+					  dev->real_num_tx_queues);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static void ifb_fill_stats_data(u64 **data,
+				struct ifb_q_stats *q_stats)
+{
+	void *stats_base = (void *)q_stats;
+	unsigned int start;
+	size_t offset;
+	int j;
+
+	do {
+		start = u64_stats_fetch_begin_irq(&q_stats->sync);
+		for (j = 0; j < IFB_Q_STATS_LEN; j++) {
+			offset = ifb_q_stats_desc[j].offset;
+			(*data)[j] = *(u64 *)(stats_base + offset);
+		}
+	} while (u64_stats_fetch_retry_irq(&q_stats->sync, start));
+
+	*data += IFB_Q_STATS_LEN;
+}
+
+static void ifb_get_ethtool_stats(struct net_device *dev,
+				  struct ethtool_stats *stats, u64 *data)
+{
+	struct ifb_dev_private *dp = netdev_priv(dev);
+	struct ifb_q_private *txp;
+	int i;
+
+	for (i = 0; i < dev->real_num_rx_queues; i++) {
+		txp = dp->tx_private + i;
+		ifb_fill_stats_data(&data, &txp->rx_stats);
+	}
+
+	for (i = 0; i < dev->real_num_tx_queues; i++) {
+		txp = dp->tx_private + i;
+		ifb_fill_stats_data(&data, &txp->tx_stats);
+	}
+}
+
+static const struct net_device_ops ifb_netdev_ops = {
+	.ndo_open	= ifb_open,
+	.ndo_stop	= ifb_close,
+	.ndo_get_stats64 = ifb_stats64,
+	.ndo_start_xmit	= ifb_xmit,
+	.ndo_validate_addr = eth_validate_addr,
+	.ndo_init	= ifb_dev_init,
+};
+
+static const struct ethtool_ops ifb_ethtool_ops = {
+	.get_strings		= ifb_get_strings,
+	.get_sset_count		= ifb_get_sset_count,
+	.get_ethtool_stats	= ifb_get_ethtool_stats,
+};
+
+#define IFB_FEATURES (NETIF_F_HW_CSUM | NETIF_F_SG  | NETIF_F_FRAGLIST	| \
+		      NETIF_F_GSO_SOFTWARE | NETIF_F_GSO_ENCAP_ALL	| \
+		      NETIF_F_HIGHDMA | NETIF_F_HW_VLAN_CTAG_TX		| \
+		      NETIF_F_HW_VLAN_STAG_TX)
+
+static void ifb_dev_free(struct net_device *dev)
+{
+	struct ifb_dev_private *dp = netdev_priv(dev);
+	struct ifb_q_private *txp = dp->tx_private;
+	int i;
+
+	for (i = 0; i < dev->num_tx_queues; i++,txp++) {
+		tasklet_kill(&txp->ifb_tasklet);
+		__skb_queue_purge(&txp->rq);
+		__skb_queue_purge(&txp->tq);
+	}
+	kfree(dp->tx_private);
+}
+
+static void ifb_setup(struct net_device *dev)
+{
+	/* Initialize the device structure. */
+	dev->netdev_ops = &ifb_netdev_ops;
+	dev->ethtool_ops = &ifb_ethtool_ops;
+
+	/* Fill in device structure with ethernet-generic values. */
+	ether_setup(dev);
+	dev->tx_queue_len = TX_Q_LIMIT;
+
+	dev->features |= IFB_FEATURES;
+	dev->hw_features |= dev->features;
+	dev->hw_enc_features |= dev->features;
+	dev->vlan_features |= IFB_FEATURES & ~(NETIF_F_HW_VLAN_CTAG_TX |
+					       NETIF_F_HW_VLAN_STAG_TX);
+
+	dev->flags |= IFF_NOARP;
+	dev->flags &= ~IFF_MULTICAST;
+	dev->priv_flags &= ~IFF_TX_SKB_SHARING;
+	netif_keep_dst(dev);
+	eth_hw_addr_random(dev);
+	dev->needs_free_netdev = true;
+	dev->priv_destructor = ifb_dev_free;
+
+	dev->min_mtu = 0;
+	dev->max_mtu = 0;
+}
+
+static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct ifb_dev_private *dp = netdev_priv(dev);
+	struct ifb_q_private *txp = dp->tx_private + skb_get_queue_mapping(skb);
+
+	ifb_update_q_stats(&txp->rx_stats, skb->len);
+
+	if (!skb->redirected || !skb->skb_iif) {
+		dev_kfree_skb(skb);
+		dev->stats.rx_dropped++;
+		return NETDEV_TX_OK;
+	}
+
+	if (skb_queue_len(&txp->rq) >= dev->tx_queue_len)
+		netif_tx_stop_queue(netdev_get_tx_queue(dev, txp->txqnum));
+
+	__skb_queue_tail(&txp->rq, skb);
+	if (!txp->tasklet_pending) {
+		txp->tasklet_pending = 1;
+		tasklet_schedule(&txp->ifb_tasklet);
+	}
+
+	return NETDEV_TX_OK;
+}
+
+static int ifb_close(struct net_device *dev)
+{
+	netif_tx_stop_all_queues(dev);
+	return 0;
+}
+
+static int ifb_open(struct net_device *dev)
+{
+	netif_tx_start_all_queues(dev);
+	return 0;
+}
+
+static int ifb_validate(struct nlattr *tb[], struct nlattr *data[],
+			struct netlink_ext_ack *extack)
+{
+	if (tb[IFLA_ADDRESS]) {
+		if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
+			return -EINVAL;
+		if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
+			return -EADDRNOTAVAIL;
+	}
+	return 0;
+}
+
+static struct rtnl_link_ops ifb_link_ops __read_mostly = {
+	.kind		= "ifb",
+	.priv_size	= sizeof(struct ifb_dev_private),
+	.setup		= ifb_setup,
+	.validate	= ifb_validate,
+};
+
+/* Number of ifb devices to be set up by this module.
+ * Note that these legacy devices have one queue.
+ * Prefer something like : ip link add ifb10 numtxqueues 8 type ifb
+ */
+static int numifbs = 2;
+module_param(numifbs, int, 0);
+MODULE_PARM_DESC(numifbs, "Number of ifb devices");
+
+static int __init ifb_init_one(int index)
+{
+	struct net_device *dev_ifb;
+	int err;
+
+	dev_ifb = alloc_netdev(sizeof(struct ifb_dev_private), "ifb%d",
+			       NET_NAME_UNKNOWN, ifb_setup);
+
+	if (!dev_ifb)
+		return -ENOMEM;
+
+	dev_ifb->rtnl_link_ops = &ifb_link_ops;
+	err = register_netdevice(dev_ifb);
+	if (err < 0)
+		goto err;
+
+	return 0;
+
+err:
+	free_netdev(dev_ifb);
+	return err;
+}
+
+static int __init ifb_init_module(void)
+{
+	int i, err;
+
+	down_write(&pernet_ops_rwsem);
+	rtnl_lock();
+	err = __rtnl_link_register(&ifb_link_ops);
+	if (err < 0)
+		goto out;
+
+	for (i = 0; i < numifbs && !err; i++) {
+		err = ifb_init_one(i);
+		cond_resched();
+	}
+	if (err)
+		__rtnl_link_unregister(&ifb_link_ops);
+
+out:
+	rtnl_unlock();
+	up_write(&pernet_ops_rwsem);
+
+	return err;
+}
+
+static void __exit ifb_cleanup_module(void)
+{
+	rtnl_link_unregister(&ifb_link_ops);
+}
+
+module_init(ifb_init_module);
+module_exit(ifb_cleanup_module);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Jamal Hadi Salim");
+MODULE_ALIAS_RTNL_LINK("ifb");