diff options
Diffstat (limited to 'net/xdp/xsk.c')
| -rw-r--r-- | net/xdp/xsk.c | 1524 |
1 files changed, 1524 insertions, 0 deletions
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c new file mode 100644 index 000000000..5c8e02d56 --- /dev/null +++ b/net/xdp/xsk.c @@ -0,0 +1,1524 @@ +// SPDX-License-Identifier: GPL-2.0 +/* XDP sockets + * + * AF_XDP sockets allows a channel between XDP programs and userspace + * applications. + * Copyright(c) 2018 Intel Corporation. + * + * Author(s): Björn Töpel <bjorn.topel@intel.com> + * Magnus Karlsson <magnus.karlsson@intel.com> + */ + +#define pr_fmt(fmt) "AF_XDP: %s: " fmt, __func__ + +#include <linux/if_xdp.h> +#include <linux/init.h> +#include <linux/sched/mm.h> +#include <linux/sched/signal.h> +#include <linux/sched/task.h> +#include <linux/socket.h> +#include <linux/file.h> +#include <linux/uaccess.h> +#include <linux/net.h> +#include <linux/netdevice.h> +#include <linux/rculist.h> +#include <net/xdp_sock_drv.h> +#include <net/busy_poll.h> +#include <net/xdp.h> + +#include "xsk_queue.h" +#include "xdp_umem.h" +#include "xsk.h" + +#define TX_BATCH_SIZE 32 + +static DEFINE_PER_CPU(struct list_head, xskmap_flush_list); + +void xsk_set_rx_need_wakeup(struct xsk_buff_pool *pool) +{ + if (pool->cached_need_wakeup & XDP_WAKEUP_RX) + return; + + pool->fq->ring->flags |= XDP_RING_NEED_WAKEUP; + pool->cached_need_wakeup |= XDP_WAKEUP_RX; +} +EXPORT_SYMBOL(xsk_set_rx_need_wakeup); + +void xsk_set_tx_need_wakeup(struct xsk_buff_pool *pool) +{ + struct xdp_sock *xs; + + if (pool->cached_need_wakeup & XDP_WAKEUP_TX) + return; + + rcu_read_lock(); + list_for_each_entry_rcu(xs, &pool->xsk_tx_list, tx_list) { + xs->tx->ring->flags |= XDP_RING_NEED_WAKEUP; + } + rcu_read_unlock(); + + pool->cached_need_wakeup |= XDP_WAKEUP_TX; +} +EXPORT_SYMBOL(xsk_set_tx_need_wakeup); + +void xsk_clear_rx_need_wakeup(struct xsk_buff_pool *pool) +{ + if (!(pool->cached_need_wakeup & XDP_WAKEUP_RX)) + return; + + pool->fq->ring->flags &= ~XDP_RING_NEED_WAKEUP; + pool->cached_need_wakeup &= ~XDP_WAKEUP_RX; +} +EXPORT_SYMBOL(xsk_clear_rx_need_wakeup); + +void xsk_clear_tx_need_wakeup(struct xsk_buff_pool *pool) +{ + struct xdp_sock *xs; + + if (!(pool->cached_need_wakeup & XDP_WAKEUP_TX)) + return; + + rcu_read_lock(); + list_for_each_entry_rcu(xs, &pool->xsk_tx_list, tx_list) { + xs->tx->ring->flags &= ~XDP_RING_NEED_WAKEUP; + } + rcu_read_unlock(); + + pool->cached_need_wakeup &= ~XDP_WAKEUP_TX; +} +EXPORT_SYMBOL(xsk_clear_tx_need_wakeup); + +bool xsk_uses_need_wakeup(struct xsk_buff_pool *pool) +{ + return pool->uses_need_wakeup; +} +EXPORT_SYMBOL(xsk_uses_need_wakeup); + +struct xsk_buff_pool *xsk_get_pool_from_qid(struct net_device *dev, + u16 queue_id) +{ + if (queue_id < dev->real_num_rx_queues) + return dev->_rx[queue_id].pool; + if (queue_id < dev->real_num_tx_queues) + return dev->_tx[queue_id].pool; + + return NULL; +} +EXPORT_SYMBOL(xsk_get_pool_from_qid); + +void xsk_clear_pool_at_qid(struct net_device *dev, u16 queue_id) +{ + if (queue_id < dev->num_rx_queues) + dev->_rx[queue_id].pool = NULL; + if (queue_id < dev->num_tx_queues) + dev->_tx[queue_id].pool = NULL; +} + +/* The buffer pool is stored both in the _rx struct and the _tx struct as we do + * not know if the device has more tx queues than rx, or the opposite. + * This might also change during run time. + */ +int xsk_reg_pool_at_qid(struct net_device *dev, struct xsk_buff_pool *pool, + u16 queue_id) +{ + if (queue_id >= max_t(unsigned int, + dev->real_num_rx_queues, + dev->real_num_tx_queues)) + return -EINVAL; + + if (queue_id < dev->real_num_rx_queues) + dev->_rx[queue_id].pool = pool; + if (queue_id < dev->real_num_tx_queues) + dev->_tx[queue_id].pool = pool; + + return 0; +} + +static int __xsk_rcv_zc(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len) +{ + struct xdp_buff_xsk *xskb = container_of(xdp, struct xdp_buff_xsk, xdp); + u64 addr; + int err; + + addr = xp_get_handle(xskb); + err = xskq_prod_reserve_desc(xs->rx, addr, len); + if (err) { + xs->rx_queue_full++; + return err; + } + + xp_release(xskb); + return 0; +} + +static void xsk_copy_xdp(struct xdp_buff *to, struct xdp_buff *from, u32 len) +{ + void *from_buf, *to_buf; + u32 metalen; + + if (unlikely(xdp_data_meta_unsupported(from))) { + from_buf = from->data; + to_buf = to->data; + metalen = 0; + } else { + from_buf = from->data_meta; + metalen = from->data - from->data_meta; + to_buf = to->data - metalen; + } + + memcpy(to_buf, from_buf, len + metalen); +} + +static int __xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp) +{ + struct xdp_buff *xsk_xdp; + int err; + u32 len; + + len = xdp->data_end - xdp->data; + if (len > xsk_pool_get_rx_frame_size(xs->pool)) { + xs->rx_dropped++; + return -ENOSPC; + } + + xsk_xdp = xsk_buff_alloc(xs->pool); + if (!xsk_xdp) { + xs->rx_dropped++; + return -ENOMEM; + } + + xsk_copy_xdp(xsk_xdp, xdp, len); + err = __xsk_rcv_zc(xs, xsk_xdp, len); + if (err) { + xsk_buff_free(xsk_xdp); + return err; + } + return 0; +} + +static bool xsk_tx_writeable(struct xdp_sock *xs) +{ + if (xskq_cons_present_entries(xs->tx) > xs->tx->nentries / 2) + return false; + + return true; +} + +static bool xsk_is_bound(struct xdp_sock *xs) +{ + if (READ_ONCE(xs->state) == XSK_BOUND) { + /* Matches smp_wmb() in bind(). */ + smp_rmb(); + return true; + } + return false; +} + +static int xsk_rcv_check(struct xdp_sock *xs, struct xdp_buff *xdp) +{ + if (!xsk_is_bound(xs)) + return -ENXIO; + + if (xs->dev != xdp->rxq->dev || xs->queue_id != xdp->rxq->queue_index) + return -EINVAL; + + sk_mark_napi_id_once_xdp(&xs->sk, xdp); + return 0; +} + +static void xsk_flush(struct xdp_sock *xs) +{ + xskq_prod_submit(xs->rx); + __xskq_cons_release(xs->pool->fq); + sock_def_readable(&xs->sk); +} + +int xsk_generic_rcv(struct xdp_sock *xs, struct xdp_buff *xdp) +{ + int err; + + spin_lock_bh(&xs->rx_lock); + err = xsk_rcv_check(xs, xdp); + if (!err) { + err = __xsk_rcv(xs, xdp); + xsk_flush(xs); + } + spin_unlock_bh(&xs->rx_lock); + return err; +} + +static int xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp) +{ + int err; + u32 len; + + err = xsk_rcv_check(xs, xdp); + if (err) + return err; + + if (xdp->rxq->mem.type == MEM_TYPE_XSK_BUFF_POOL) { + len = xdp->data_end - xdp->data; + return __xsk_rcv_zc(xs, xdp, len); + } + + err = __xsk_rcv(xs, xdp); + if (!err) + xdp_return_buff(xdp); + return err; +} + +int __xsk_map_redirect(struct xdp_sock *xs, struct xdp_buff *xdp) +{ + struct list_head *flush_list = this_cpu_ptr(&xskmap_flush_list); + int err; + + err = xsk_rcv(xs, xdp); + if (err) + return err; + + if (!xs->flush_node.prev) + list_add(&xs->flush_node, flush_list); + + return 0; +} + +void __xsk_map_flush(void) +{ + struct list_head *flush_list = this_cpu_ptr(&xskmap_flush_list); + struct xdp_sock *xs, *tmp; + + list_for_each_entry_safe(xs, tmp, flush_list, flush_node) { + xsk_flush(xs); + __list_del_clearprev(&xs->flush_node); + } +} + +void xsk_tx_completed(struct xsk_buff_pool *pool, u32 nb_entries) +{ + xskq_prod_submit_n(pool->cq, nb_entries); +} +EXPORT_SYMBOL(xsk_tx_completed); + +void xsk_tx_release(struct xsk_buff_pool *pool) +{ + struct xdp_sock *xs; + + rcu_read_lock(); + list_for_each_entry_rcu(xs, &pool->xsk_tx_list, tx_list) { + __xskq_cons_release(xs->tx); + if (xsk_tx_writeable(xs)) + xs->sk.sk_write_space(&xs->sk); + } + rcu_read_unlock(); +} +EXPORT_SYMBOL(xsk_tx_release); + +bool xsk_tx_peek_desc(struct xsk_buff_pool *pool, struct xdp_desc *desc) +{ + struct xdp_sock *xs; + + rcu_read_lock(); + list_for_each_entry_rcu(xs, &pool->xsk_tx_list, tx_list) { + if (!xskq_cons_peek_desc(xs->tx, desc, pool)) { + xs->tx->queue_empty_descs++; + continue; + } + + /* This is the backpressure mechanism for the Tx path. + * Reserve space in the completion queue and only proceed + * if there is space in it. This avoids having to implement + * any buffering in the Tx path. + */ + if (xskq_prod_reserve_addr(pool->cq, desc->addr)) + goto out; + + xskq_cons_release(xs->tx); + rcu_read_unlock(); + return true; + } + +out: + rcu_read_unlock(); + return false; +} +EXPORT_SYMBOL(xsk_tx_peek_desc); + +static u32 xsk_tx_peek_release_fallback(struct xsk_buff_pool *pool, u32 max_entries) +{ + struct xdp_desc *descs = pool->tx_descs; + u32 nb_pkts = 0; + + while (nb_pkts < max_entries && xsk_tx_peek_desc(pool, &descs[nb_pkts])) + nb_pkts++; + + xsk_tx_release(pool); + return nb_pkts; +} + +u32 xsk_tx_peek_release_desc_batch(struct xsk_buff_pool *pool, u32 nb_pkts) +{ + struct xdp_sock *xs; + + rcu_read_lock(); + if (!list_is_singular(&pool->xsk_tx_list)) { + /* Fallback to the non-batched version */ + rcu_read_unlock(); + return xsk_tx_peek_release_fallback(pool, nb_pkts); + } + + xs = list_first_or_null_rcu(&pool->xsk_tx_list, struct xdp_sock, tx_list); + if (!xs) { + nb_pkts = 0; + goto out; + } + + nb_pkts = xskq_cons_nb_entries(xs->tx, nb_pkts); + + /* This is the backpressure mechanism for the Tx path. Try to + * reserve space in the completion queue for all packets, but + * if there are fewer slots available, just process that many + * packets. This avoids having to implement any buffering in + * the Tx path. + */ + nb_pkts = xskq_prod_nb_free(pool->cq, nb_pkts); + if (!nb_pkts) + goto out; + + nb_pkts = xskq_cons_read_desc_batch(xs->tx, pool, nb_pkts); + if (!nb_pkts) { + xs->tx->queue_empty_descs++; + goto out; + } + + __xskq_cons_release(xs->tx); + xskq_prod_write_addr_batch(pool->cq, pool->tx_descs, nb_pkts); + xs->sk.sk_write_space(&xs->sk); + +out: + rcu_read_unlock(); + return nb_pkts; +} +EXPORT_SYMBOL(xsk_tx_peek_release_desc_batch); + +static int xsk_wakeup(struct xdp_sock *xs, u8 flags) +{ + struct net_device *dev = xs->dev; + + return dev->netdev_ops->ndo_xsk_wakeup(dev, xs->queue_id, flags); +} + +static void xsk_destruct_skb(struct sk_buff *skb) +{ + u64 addr = (u64)(long)skb_shinfo(skb)->destructor_arg; + struct xdp_sock *xs = xdp_sk(skb->sk); + unsigned long flags; + + spin_lock_irqsave(&xs->pool->cq_lock, flags); + xskq_prod_submit_addr(xs->pool->cq, addr); + spin_unlock_irqrestore(&xs->pool->cq_lock, flags); + + sock_wfree(skb); +} + +static struct sk_buff *xsk_build_skb_zerocopy(struct xdp_sock *xs, + struct xdp_desc *desc) +{ + struct xsk_buff_pool *pool = xs->pool; + u32 hr, len, ts, offset, copy, copied; + struct sk_buff *skb; + struct page *page; + void *buffer; + int err, i; + u64 addr; + + hr = max(NET_SKB_PAD, L1_CACHE_ALIGN(xs->dev->needed_headroom)); + + skb = sock_alloc_send_skb(&xs->sk, hr, 1, &err); + if (unlikely(!skb)) + return ERR_PTR(err); + + skb_reserve(skb, hr); + + addr = desc->addr; + len = desc->len; + ts = pool->unaligned ? len : pool->chunk_size; + + buffer = xsk_buff_raw_get_data(pool, addr); + offset = offset_in_page(buffer); + addr = buffer - pool->addrs; + + for (copied = 0, i = 0; copied < len; i++) { + page = pool->umem->pgs[addr >> PAGE_SHIFT]; + get_page(page); + + copy = min_t(u32, PAGE_SIZE - offset, len - copied); + skb_fill_page_desc(skb, i, page, offset, copy); + + copied += copy; + addr += copy; + offset = 0; + } + + skb->len += len; + skb->data_len += len; + skb->truesize += ts; + + refcount_add(ts, &xs->sk.sk_wmem_alloc); + + return skb; +} + +static struct sk_buff *xsk_build_skb(struct xdp_sock *xs, + struct xdp_desc *desc) +{ + struct net_device *dev = xs->dev; + struct sk_buff *skb; + + if (dev->priv_flags & IFF_TX_SKB_NO_LINEAR) { + skb = xsk_build_skb_zerocopy(xs, desc); + if (IS_ERR(skb)) + return skb; + } else { + u32 hr, tr, len; + void *buffer; + int err; + + hr = max(NET_SKB_PAD, L1_CACHE_ALIGN(dev->needed_headroom)); + tr = dev->needed_tailroom; + len = desc->len; + + skb = sock_alloc_send_skb(&xs->sk, hr + len + tr, 1, &err); + if (unlikely(!skb)) + return ERR_PTR(err); + + skb_reserve(skb, hr); + skb_put(skb, len); + + buffer = xsk_buff_raw_get_data(xs->pool, desc->addr); + err = skb_store_bits(skb, 0, buffer, len); + if (unlikely(err)) { + kfree_skb(skb); + return ERR_PTR(err); + } + } + + skb->dev = dev; + skb->priority = xs->sk.sk_priority; + skb->mark = READ_ONCE(xs->sk.sk_mark); + skb_shinfo(skb)->destructor_arg = (void *)(long)desc->addr; + skb->destructor = xsk_destruct_skb; + + return skb; +} + +static int __xsk_generic_xmit(struct sock *sk) +{ + struct xdp_sock *xs = xdp_sk(sk); + u32 max_batch = TX_BATCH_SIZE; + bool sent_frame = false; + struct xdp_desc desc; + struct sk_buff *skb; + unsigned long flags; + int err = 0; + + mutex_lock(&xs->mutex); + + /* Since we dropped the RCU read lock, the socket state might have changed. */ + if (unlikely(!xsk_is_bound(xs))) { + err = -ENXIO; + goto out; + } + + if (xs->queue_id >= xs->dev->real_num_tx_queues) + goto out; + + while (xskq_cons_peek_desc(xs->tx, &desc, xs->pool)) { + if (max_batch-- == 0) { + err = -EAGAIN; + goto out; + } + + /* This is the backpressure mechanism for the Tx path. + * Reserve space in the completion queue and only proceed + * if there is space in it. This avoids having to implement + * any buffering in the Tx path. + */ + spin_lock_irqsave(&xs->pool->cq_lock, flags); + if (xskq_prod_reserve(xs->pool->cq)) { + spin_unlock_irqrestore(&xs->pool->cq_lock, flags); + goto out; + } + spin_unlock_irqrestore(&xs->pool->cq_lock, flags); + + skb = xsk_build_skb(xs, &desc); + if (IS_ERR(skb)) { + err = PTR_ERR(skb); + spin_lock_irqsave(&xs->pool->cq_lock, flags); + xskq_prod_cancel(xs->pool->cq); + spin_unlock_irqrestore(&xs->pool->cq_lock, flags); + goto out; + } + + err = __dev_direct_xmit(skb, xs->queue_id); + if (err == NETDEV_TX_BUSY) { + /* Tell user-space to retry the send */ + skb->destructor = sock_wfree; + spin_lock_irqsave(&xs->pool->cq_lock, flags); + xskq_prod_cancel(xs->pool->cq); + spin_unlock_irqrestore(&xs->pool->cq_lock, flags); + /* Free skb without triggering the perf drop trace */ + consume_skb(skb); + err = -EAGAIN; + goto out; + } + + xskq_cons_release(xs->tx); + /* Ignore NET_XMIT_CN as packet might have been sent */ + if (err == NET_XMIT_DROP) { + /* SKB completed but not sent */ + err = -EBUSY; + goto out; + } + + sent_frame = true; + } + + xs->tx->queue_empty_descs++; + +out: + if (sent_frame) + if (xsk_tx_writeable(xs)) + sk->sk_write_space(sk); + + mutex_unlock(&xs->mutex); + return err; +} + +static int xsk_generic_xmit(struct sock *sk) +{ + int ret; + + /* Drop the RCU lock since the SKB path might sleep. */ + rcu_read_unlock(); + ret = __xsk_generic_xmit(sk); + /* Reaquire RCU lock before going into common code. */ + rcu_read_lock(); + + return ret; +} + +static bool xsk_no_wakeup(struct sock *sk) +{ +#ifdef CONFIG_NET_RX_BUSY_POLL + /* Prefer busy-polling, skip the wakeup. */ + return READ_ONCE(sk->sk_prefer_busy_poll) && READ_ONCE(sk->sk_ll_usec) && + READ_ONCE(sk->sk_napi_id) >= MIN_NAPI_ID; +#else + return false; +#endif +} + +static int xsk_check_common(struct xdp_sock *xs) +{ + if (unlikely(!xsk_is_bound(xs))) + return -ENXIO; + if (unlikely(!(xs->dev->flags & IFF_UP))) + return -ENETDOWN; + + return 0; +} + +static int __xsk_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len) +{ + bool need_wait = !(m->msg_flags & MSG_DONTWAIT); + struct sock *sk = sock->sk; + struct xdp_sock *xs = xdp_sk(sk); + struct xsk_buff_pool *pool; + int err; + + err = xsk_check_common(xs); + if (err) + return err; + if (unlikely(need_wait)) + return -EOPNOTSUPP; + if (unlikely(!xs->tx)) + return -ENOBUFS; + + if (sk_can_busy_loop(sk)) { + if (xs->zc) + __sk_mark_napi_id_once(sk, xsk_pool_get_napi_id(xs->pool)); + sk_busy_loop(sk, 1); /* only support non-blocking sockets */ + } + + if (xs->zc && xsk_no_wakeup(sk)) + return 0; + + pool = xs->pool; + if (pool->cached_need_wakeup & XDP_WAKEUP_TX) { + if (xs->zc) + return xsk_wakeup(xs, XDP_WAKEUP_TX); + return xsk_generic_xmit(sk); + } + return 0; +} + +static int xsk_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len) +{ + int ret; + + rcu_read_lock(); + ret = __xsk_sendmsg(sock, m, total_len); + rcu_read_unlock(); + + return ret; +} + +static int __xsk_recvmsg(struct socket *sock, struct msghdr *m, size_t len, int flags) +{ + bool need_wait = !(flags & MSG_DONTWAIT); + struct sock *sk = sock->sk; + struct xdp_sock *xs = xdp_sk(sk); + int err; + + err = xsk_check_common(xs); + if (err) + return err; + if (unlikely(!xs->rx)) + return -ENOBUFS; + if (unlikely(need_wait)) + return -EOPNOTSUPP; + + if (sk_can_busy_loop(sk)) + sk_busy_loop(sk, 1); /* only support non-blocking sockets */ + + if (xsk_no_wakeup(sk)) + return 0; + + if (xs->pool->cached_need_wakeup & XDP_WAKEUP_RX && xs->zc) + return xsk_wakeup(xs, XDP_WAKEUP_RX); + return 0; +} + +static int xsk_recvmsg(struct socket *sock, struct msghdr *m, size_t len, int flags) +{ + int ret; + + rcu_read_lock(); + ret = __xsk_recvmsg(sock, m, len, flags); + rcu_read_unlock(); + + return ret; +} + +static __poll_t xsk_poll(struct file *file, struct socket *sock, + struct poll_table_struct *wait) +{ + __poll_t mask = 0; + struct sock *sk = sock->sk; + struct xdp_sock *xs = xdp_sk(sk); + struct xsk_buff_pool *pool; + + sock_poll_wait(file, sock, wait); + + rcu_read_lock(); + if (xsk_check_common(xs)) + goto out; + + pool = xs->pool; + + if (pool->cached_need_wakeup) { + if (xs->zc) + xsk_wakeup(xs, pool->cached_need_wakeup); + else if (xs->tx) + /* Poll needs to drive Tx also in copy mode */ + xsk_generic_xmit(sk); + } + + if (xs->rx && !xskq_prod_is_empty(xs->rx)) + mask |= EPOLLIN | EPOLLRDNORM; + if (xs->tx && xsk_tx_writeable(xs)) + mask |= EPOLLOUT | EPOLLWRNORM; +out: + rcu_read_unlock(); + return mask; +} + +static int xsk_init_queue(u32 entries, struct xsk_queue **queue, + bool umem_queue) +{ + struct xsk_queue *q; + + if (entries == 0 || *queue || !is_power_of_2(entries)) + return -EINVAL; + + q = xskq_create(entries, umem_queue); + if (!q) + return -ENOMEM; + + /* Make sure queue is ready before it can be seen by others */ + smp_wmb(); + WRITE_ONCE(*queue, q); + return 0; +} + +static void xsk_unbind_dev(struct xdp_sock *xs) +{ + struct net_device *dev = xs->dev; + + if (xs->state != XSK_BOUND) + return; + WRITE_ONCE(xs->state, XSK_UNBOUND); + + /* Wait for driver to stop using the xdp socket. */ + xp_del_xsk(xs->pool, xs); + synchronize_net(); + dev_put(dev); +} + +static struct xsk_map *xsk_get_map_list_entry(struct xdp_sock *xs, + struct xdp_sock __rcu ***map_entry) +{ + struct xsk_map *map = NULL; + struct xsk_map_node *node; + + *map_entry = NULL; + + spin_lock_bh(&xs->map_list_lock); + node = list_first_entry_or_null(&xs->map_list, struct xsk_map_node, + node); + if (node) { + bpf_map_inc(&node->map->map); + map = node->map; + *map_entry = node->map_entry; + } + spin_unlock_bh(&xs->map_list_lock); + return map; +} + +static void xsk_delete_from_maps(struct xdp_sock *xs) +{ + /* This function removes the current XDP socket from all the + * maps it resides in. We need to take extra care here, due to + * the two locks involved. Each map has a lock synchronizing + * updates to the entries, and each socket has a lock that + * synchronizes access to the list of maps (map_list). For + * deadlock avoidance the locks need to be taken in the order + * "map lock"->"socket map list lock". We start off by + * accessing the socket map list, and take a reference to the + * map to guarantee existence between the + * xsk_get_map_list_entry() and xsk_map_try_sock_delete() + * calls. Then we ask the map to remove the socket, which + * tries to remove the socket from the map. Note that there + * might be updates to the map between + * xsk_get_map_list_entry() and xsk_map_try_sock_delete(). + */ + struct xdp_sock __rcu **map_entry = NULL; + struct xsk_map *map; + + while ((map = xsk_get_map_list_entry(xs, &map_entry))) { + xsk_map_try_sock_delete(map, xs, map_entry); + bpf_map_put(&map->map); + } +} + +static int xsk_release(struct socket *sock) +{ + struct sock *sk = sock->sk; + struct xdp_sock *xs = xdp_sk(sk); + struct net *net; + + if (!sk) + return 0; + + net = sock_net(sk); + + mutex_lock(&net->xdp.lock); + sk_del_node_init_rcu(sk); + mutex_unlock(&net->xdp.lock); + + sock_prot_inuse_add(net, sk->sk_prot, -1); + + xsk_delete_from_maps(xs); + mutex_lock(&xs->mutex); + xsk_unbind_dev(xs); + mutex_unlock(&xs->mutex); + + xskq_destroy(xs->rx); + xskq_destroy(xs->tx); + xskq_destroy(xs->fq_tmp); + xskq_destroy(xs->cq_tmp); + + sock_orphan(sk); + sock->sk = NULL; + + sk_refcnt_debug_release(sk); + sock_put(sk); + + return 0; +} + +static struct socket *xsk_lookup_xsk_from_fd(int fd) +{ + struct socket *sock; + int err; + + sock = sockfd_lookup(fd, &err); + if (!sock) + return ERR_PTR(-ENOTSOCK); + + if (sock->sk->sk_family != PF_XDP) { + sockfd_put(sock); + return ERR_PTR(-ENOPROTOOPT); + } + + return sock; +} + +static bool xsk_validate_queues(struct xdp_sock *xs) +{ + return xs->fq_tmp && xs->cq_tmp; +} + +static int xsk_bind(struct socket *sock, struct sockaddr *addr, int addr_len) +{ + struct sockaddr_xdp *sxdp = (struct sockaddr_xdp *)addr; + struct sock *sk = sock->sk; + struct xdp_sock *xs = xdp_sk(sk); + struct net_device *dev; + int bound_dev_if; + u32 flags, qid; + int err = 0; + + if (addr_len < sizeof(struct sockaddr_xdp)) + return -EINVAL; + if (sxdp->sxdp_family != AF_XDP) + return -EINVAL; + + flags = sxdp->sxdp_flags; + if (flags & ~(XDP_SHARED_UMEM | XDP_COPY | XDP_ZEROCOPY | + XDP_USE_NEED_WAKEUP)) + return -EINVAL; + + bound_dev_if = READ_ONCE(sk->sk_bound_dev_if); + if (bound_dev_if && bound_dev_if != sxdp->sxdp_ifindex) + return -EINVAL; + + rtnl_lock(); + mutex_lock(&xs->mutex); + if (xs->state != XSK_READY) { + err = -EBUSY; + goto out_release; + } + + dev = dev_get_by_index(sock_net(sk), sxdp->sxdp_ifindex); + if (!dev) { + err = -ENODEV; + goto out_release; + } + + if (!xs->rx && !xs->tx) { + err = -EINVAL; + goto out_unlock; + } + + qid = sxdp->sxdp_queue_id; + + if (flags & XDP_SHARED_UMEM) { + struct xdp_sock *umem_xs; + struct socket *sock; + + if ((flags & XDP_COPY) || (flags & XDP_ZEROCOPY) || + (flags & XDP_USE_NEED_WAKEUP)) { + /* Cannot specify flags for shared sockets. */ + err = -EINVAL; + goto out_unlock; + } + + if (xs->umem) { + /* We have already our own. */ + err = -EINVAL; + goto out_unlock; + } + + sock = xsk_lookup_xsk_from_fd(sxdp->sxdp_shared_umem_fd); + if (IS_ERR(sock)) { + err = PTR_ERR(sock); + goto out_unlock; + } + + umem_xs = xdp_sk(sock->sk); + if (!xsk_is_bound(umem_xs)) { + err = -EBADF; + sockfd_put(sock); + goto out_unlock; + } + + if (umem_xs->queue_id != qid || umem_xs->dev != dev) { + /* Share the umem with another socket on another qid + * and/or device. + */ + xs->pool = xp_create_and_assign_umem(xs, + umem_xs->umem); + if (!xs->pool) { + err = -ENOMEM; + sockfd_put(sock); + goto out_unlock; + } + + err = xp_assign_dev_shared(xs->pool, umem_xs, dev, + qid); + if (err) { + xp_destroy(xs->pool); + xs->pool = NULL; + sockfd_put(sock); + goto out_unlock; + } + } else { + /* Share the buffer pool with the other socket. */ + if (xs->fq_tmp || xs->cq_tmp) { + /* Do not allow setting your own fq or cq. */ + err = -EINVAL; + sockfd_put(sock); + goto out_unlock; + } + + xp_get_pool(umem_xs->pool); + xs->pool = umem_xs->pool; + + /* If underlying shared umem was created without Tx + * ring, allocate Tx descs array that Tx batching API + * utilizes + */ + if (xs->tx && !xs->pool->tx_descs) { + err = xp_alloc_tx_descs(xs->pool, xs); + if (err) { + xp_put_pool(xs->pool); + xs->pool = NULL; + sockfd_put(sock); + goto out_unlock; + } + } + } + + xdp_get_umem(umem_xs->umem); + WRITE_ONCE(xs->umem, umem_xs->umem); + sockfd_put(sock); + } else if (!xs->umem || !xsk_validate_queues(xs)) { + err = -EINVAL; + goto out_unlock; + } else { + /* This xsk has its own umem. */ + xs->pool = xp_create_and_assign_umem(xs, xs->umem); + if (!xs->pool) { + err = -ENOMEM; + goto out_unlock; + } + + err = xp_assign_dev(xs->pool, dev, qid, flags); + if (err) { + xp_destroy(xs->pool); + xs->pool = NULL; + goto out_unlock; + } + } + + /* FQ and CQ are now owned by the buffer pool and cleaned up with it. */ + xs->fq_tmp = NULL; + xs->cq_tmp = NULL; + + xs->dev = dev; + xs->zc = xs->umem->zc; + xs->queue_id = qid; + xp_add_xsk(xs->pool, xs); + +out_unlock: + if (err) { + dev_put(dev); + } else { + /* Matches smp_rmb() in bind() for shared umem + * sockets, and xsk_is_bound(). + */ + smp_wmb(); + WRITE_ONCE(xs->state, XSK_BOUND); + } +out_release: + mutex_unlock(&xs->mutex); + rtnl_unlock(); + return err; +} + +struct xdp_umem_reg_v1 { + __u64 addr; /* Start of packet data area */ + __u64 len; /* Length of packet data area */ + __u32 chunk_size; + __u32 headroom; +}; + +static int xsk_setsockopt(struct socket *sock, int level, int optname, + sockptr_t optval, unsigned int optlen) +{ + struct sock *sk = sock->sk; + struct xdp_sock *xs = xdp_sk(sk); + int err; + + if (level != SOL_XDP) + return -ENOPROTOOPT; + + switch (optname) { + case XDP_RX_RING: + case XDP_TX_RING: + { + struct xsk_queue **q; + int entries; + + if (optlen < sizeof(entries)) + return -EINVAL; + if (copy_from_sockptr(&entries, optval, sizeof(entries))) + return -EFAULT; + + mutex_lock(&xs->mutex); + if (xs->state != XSK_READY) { + mutex_unlock(&xs->mutex); + return -EBUSY; + } + q = (optname == XDP_TX_RING) ? &xs->tx : &xs->rx; + err = xsk_init_queue(entries, q, false); + if (!err && optname == XDP_TX_RING) + /* Tx needs to be explicitly woken up the first time */ + xs->tx->ring->flags |= XDP_RING_NEED_WAKEUP; + mutex_unlock(&xs->mutex); + return err; + } + case XDP_UMEM_REG: + { + size_t mr_size = sizeof(struct xdp_umem_reg); + struct xdp_umem_reg mr = {}; + struct xdp_umem *umem; + + if (optlen < sizeof(struct xdp_umem_reg_v1)) + return -EINVAL; + else if (optlen < sizeof(mr)) + mr_size = sizeof(struct xdp_umem_reg_v1); + + if (copy_from_sockptr(&mr, optval, mr_size)) + return -EFAULT; + + mutex_lock(&xs->mutex); + if (xs->state != XSK_READY || xs->umem) { + mutex_unlock(&xs->mutex); + return -EBUSY; + } + + umem = xdp_umem_create(&mr); + if (IS_ERR(umem)) { + mutex_unlock(&xs->mutex); + return PTR_ERR(umem); + } + + /* Make sure umem is ready before it can be seen by others */ + smp_wmb(); + WRITE_ONCE(xs->umem, umem); + mutex_unlock(&xs->mutex); + return 0; + } + case XDP_UMEM_FILL_RING: + case XDP_UMEM_COMPLETION_RING: + { + struct xsk_queue **q; + int entries; + + if (copy_from_sockptr(&entries, optval, sizeof(entries))) + return -EFAULT; + + mutex_lock(&xs->mutex); + if (xs->state != XSK_READY) { + mutex_unlock(&xs->mutex); + return -EBUSY; + } + + q = (optname == XDP_UMEM_FILL_RING) ? &xs->fq_tmp : + &xs->cq_tmp; + err = xsk_init_queue(entries, q, true); + mutex_unlock(&xs->mutex); + return err; + } + default: + break; + } + + return -ENOPROTOOPT; +} + +static void xsk_enter_rxtx_offsets(struct xdp_ring_offset_v1 *ring) +{ + ring->producer = offsetof(struct xdp_rxtx_ring, ptrs.producer); + ring->consumer = offsetof(struct xdp_rxtx_ring, ptrs.consumer); + ring->desc = offsetof(struct xdp_rxtx_ring, desc); +} + +static void xsk_enter_umem_offsets(struct xdp_ring_offset_v1 *ring) +{ + ring->producer = offsetof(struct xdp_umem_ring, ptrs.producer); + ring->consumer = offsetof(struct xdp_umem_ring, ptrs.consumer); + ring->desc = offsetof(struct xdp_umem_ring, desc); +} + +struct xdp_statistics_v1 { + __u64 rx_dropped; + __u64 rx_invalid_descs; + __u64 tx_invalid_descs; +}; + +static int xsk_getsockopt(struct socket *sock, int level, int optname, + char __user *optval, int __user *optlen) +{ + struct sock *sk = sock->sk; + struct xdp_sock *xs = xdp_sk(sk); + int len; + + if (level != SOL_XDP) + return -ENOPROTOOPT; + + if (get_user(len, optlen)) + return -EFAULT; + if (len < 0) + return -EINVAL; + + switch (optname) { + case XDP_STATISTICS: + { + struct xdp_statistics stats = {}; + bool extra_stats = true; + size_t stats_size; + + if (len < sizeof(struct xdp_statistics_v1)) { + return -EINVAL; + } else if (len < sizeof(stats)) { + extra_stats = false; + stats_size = sizeof(struct xdp_statistics_v1); + } else { + stats_size = sizeof(stats); + } + + mutex_lock(&xs->mutex); + stats.rx_dropped = xs->rx_dropped; + if (extra_stats) { + stats.rx_ring_full = xs->rx_queue_full; + stats.rx_fill_ring_empty_descs = + xs->pool ? xskq_nb_queue_empty_descs(xs->pool->fq) : 0; + stats.tx_ring_empty_descs = xskq_nb_queue_empty_descs(xs->tx); + } else { + stats.rx_dropped += xs->rx_queue_full; + } + stats.rx_invalid_descs = xskq_nb_invalid_descs(xs->rx); + stats.tx_invalid_descs = xskq_nb_invalid_descs(xs->tx); + mutex_unlock(&xs->mutex); + + if (copy_to_user(optval, &stats, stats_size)) + return -EFAULT; + if (put_user(stats_size, optlen)) + return -EFAULT; + + return 0; + } + case XDP_MMAP_OFFSETS: + { + struct xdp_mmap_offsets off; + struct xdp_mmap_offsets_v1 off_v1; + bool flags_supported = true; + void *to_copy; + + if (len < sizeof(off_v1)) + return -EINVAL; + else if (len < sizeof(off)) + flags_supported = false; + + if (flags_supported) { + /* xdp_ring_offset is identical to xdp_ring_offset_v1 + * except for the flags field added to the end. + */ + xsk_enter_rxtx_offsets((struct xdp_ring_offset_v1 *) + &off.rx); + xsk_enter_rxtx_offsets((struct xdp_ring_offset_v1 *) + &off.tx); + xsk_enter_umem_offsets((struct xdp_ring_offset_v1 *) + &off.fr); + xsk_enter_umem_offsets((struct xdp_ring_offset_v1 *) + &off.cr); + off.rx.flags = offsetof(struct xdp_rxtx_ring, + ptrs.flags); + off.tx.flags = offsetof(struct xdp_rxtx_ring, + ptrs.flags); + off.fr.flags = offsetof(struct xdp_umem_ring, + ptrs.flags); + off.cr.flags = offsetof(struct xdp_umem_ring, + ptrs.flags); + + len = sizeof(off); + to_copy = &off; + } else { + xsk_enter_rxtx_offsets(&off_v1.rx); + xsk_enter_rxtx_offsets(&off_v1.tx); + xsk_enter_umem_offsets(&off_v1.fr); + xsk_enter_umem_offsets(&off_v1.cr); + + len = sizeof(off_v1); + to_copy = &off_v1; + } + + if (copy_to_user(optval, to_copy, len)) + return -EFAULT; + if (put_user(len, optlen)) + return -EFAULT; + + return 0; + } + case XDP_OPTIONS: + { + struct xdp_options opts = {}; + + if (len < sizeof(opts)) + return -EINVAL; + + mutex_lock(&xs->mutex); + if (xs->zc) + opts.flags |= XDP_OPTIONS_ZEROCOPY; + mutex_unlock(&xs->mutex); + + len = sizeof(opts); + if (copy_to_user(optval, &opts, len)) + return -EFAULT; + if (put_user(len, optlen)) + return -EFAULT; + + return 0; + } + default: + break; + } + + return -EOPNOTSUPP; +} + +static int xsk_mmap(struct file *file, struct socket *sock, + struct vm_area_struct *vma) +{ + loff_t offset = (loff_t)vma->vm_pgoff << PAGE_SHIFT; + unsigned long size = vma->vm_end - vma->vm_start; + struct xdp_sock *xs = xdp_sk(sock->sk); + struct xsk_queue *q = NULL; + unsigned long pfn; + struct page *qpg; + + if (READ_ONCE(xs->state) != XSK_READY) + return -EBUSY; + + if (offset == XDP_PGOFF_RX_RING) { + q = READ_ONCE(xs->rx); + } else if (offset == XDP_PGOFF_TX_RING) { + q = READ_ONCE(xs->tx); + } else { + /* Matches the smp_wmb() in XDP_UMEM_REG */ + smp_rmb(); + if (offset == XDP_UMEM_PGOFF_FILL_RING) + q = READ_ONCE(xs->fq_tmp); + else if (offset == XDP_UMEM_PGOFF_COMPLETION_RING) + q = READ_ONCE(xs->cq_tmp); + } + + if (!q) + return -EINVAL; + + /* Matches the smp_wmb() in xsk_init_queue */ + smp_rmb(); + qpg = virt_to_head_page(q->ring); + if (size > page_size(qpg)) + return -EINVAL; + + pfn = virt_to_phys(q->ring) >> PAGE_SHIFT; + return remap_pfn_range(vma, vma->vm_start, pfn, + size, vma->vm_page_prot); +} + +static int xsk_notifier(struct notifier_block *this, + unsigned long msg, void *ptr) +{ + struct net_device *dev = netdev_notifier_info_to_dev(ptr); + struct net *net = dev_net(dev); + struct sock *sk; + + switch (msg) { + case NETDEV_UNREGISTER: + mutex_lock(&net->xdp.lock); + sk_for_each(sk, &net->xdp.list) { + struct xdp_sock *xs = xdp_sk(sk); + + mutex_lock(&xs->mutex); + if (xs->dev == dev) { + sk->sk_err = ENETDOWN; + if (!sock_flag(sk, SOCK_DEAD)) + sk_error_report(sk); + + xsk_unbind_dev(xs); + + /* Clear device references. */ + xp_clear_dev(xs->pool); + } + mutex_unlock(&xs->mutex); + } + mutex_unlock(&net->xdp.lock); + break; + } + return NOTIFY_DONE; +} + +static struct proto xsk_proto = { + .name = "XDP", + .owner = THIS_MODULE, + .obj_size = sizeof(struct xdp_sock), +}; + +static const struct proto_ops xsk_proto_ops = { + .family = PF_XDP, + .owner = THIS_MODULE, + .release = xsk_release, + .bind = xsk_bind, + .connect = sock_no_connect, + .socketpair = sock_no_socketpair, + .accept = sock_no_accept, + .getname = sock_no_getname, + .poll = xsk_poll, + .ioctl = sock_no_ioctl, + .listen = sock_no_listen, + .shutdown = sock_no_shutdown, + .setsockopt = xsk_setsockopt, + .getsockopt = xsk_getsockopt, + .sendmsg = xsk_sendmsg, + .recvmsg = xsk_recvmsg, + .mmap = xsk_mmap, + .sendpage = sock_no_sendpage, +}; + +static void xsk_destruct(struct sock *sk) +{ + struct xdp_sock *xs = xdp_sk(sk); + + if (!sock_flag(sk, SOCK_DEAD)) + return; + + if (!xp_put_pool(xs->pool)) + xdp_put_umem(xs->umem, !xs->pool); + + sk_refcnt_debug_dec(sk); +} + +static int xsk_create(struct net *net, struct socket *sock, int protocol, + int kern) +{ + struct xdp_sock *xs; + struct sock *sk; + + if (!ns_capable(net->user_ns, CAP_NET_RAW)) + return -EPERM; + if (sock->type != SOCK_RAW) + return -ESOCKTNOSUPPORT; + + if (protocol) + return -EPROTONOSUPPORT; + + sock->state = SS_UNCONNECTED; + + sk = sk_alloc(net, PF_XDP, GFP_KERNEL, &xsk_proto, kern); + if (!sk) + return -ENOBUFS; + + sock->ops = &xsk_proto_ops; + + sock_init_data(sock, sk); + + sk->sk_family = PF_XDP; + + sk->sk_destruct = xsk_destruct; + sk_refcnt_debug_inc(sk); + + sock_set_flag(sk, SOCK_RCU_FREE); + + xs = xdp_sk(sk); + xs->state = XSK_READY; + mutex_init(&xs->mutex); + spin_lock_init(&xs->rx_lock); + + INIT_LIST_HEAD(&xs->map_list); + spin_lock_init(&xs->map_list_lock); + + mutex_lock(&net->xdp.lock); + sk_add_node_rcu(sk, &net->xdp.list); + mutex_unlock(&net->xdp.lock); + + sock_prot_inuse_add(net, &xsk_proto, 1); + + return 0; +} + +static const struct net_proto_family xsk_family_ops = { + .family = PF_XDP, + .create = xsk_create, + .owner = THIS_MODULE, +}; + +static struct notifier_block xsk_netdev_notifier = { + .notifier_call = xsk_notifier, +}; + +static int __net_init xsk_net_init(struct net *net) +{ + mutex_init(&net->xdp.lock); + INIT_HLIST_HEAD(&net->xdp.list); + return 0; +} + +static void __net_exit xsk_net_exit(struct net *net) +{ + WARN_ON_ONCE(!hlist_empty(&net->xdp.list)); +} + +static struct pernet_operations xsk_net_ops = { + .init = xsk_net_init, + .exit = xsk_net_exit, +}; + +static int __init xsk_init(void) +{ + int err, cpu; + + err = proto_register(&xsk_proto, 0 /* no slab */); + if (err) + goto out; + + err = sock_register(&xsk_family_ops); + if (err) + goto out_proto; + + err = register_pernet_subsys(&xsk_net_ops); + if (err) + goto out_sk; + + err = register_netdevice_notifier(&xsk_netdev_notifier); + if (err) + goto out_pernet; + + for_each_possible_cpu(cpu) + INIT_LIST_HEAD(&per_cpu(xskmap_flush_list, cpu)); + return 0; + +out_pernet: + unregister_pernet_subsys(&xsk_net_ops); +out_sk: + sock_unregister(PF_XDP); +out_proto: + proto_unregister(&xsk_proto); +out: + return err; +} + +fs_initcall(xsk_init); |