From d1396004dd868642ea2596abe058d96dcf97990f Mon Sep 17 00:00:00 2001 From: Toshiaki Makita Date: Fri, 3 Aug 2018 16:58:17 +0900 Subject: veth: Add XDP TX and REDIRECT This allows further redirection of xdp_frames like NIC -> veth--veth -> veth--veth (XDP) (XDP) (XDP) The intermediate XDP, redirecting packets from NIC to the other veth, reuses xdp_mem_info from NIC so that page recycling of the NIC works on the destination veth's XDP. In this way return_frame is not fully guarded by NAPI, since another NAPI handler on another cpu may use the same xdp_mem_info concurrently. Thus disable napi_direct by xdp_set_return_frame_no_direct() during the NAPI context. v8: - Don't use xdp_frame pointer address for data_hard_start of xdp_buff. v4: - Use xdp_[set|clear]_return_frame_no_direct() instead of a flag in xdp_mem_info. v3: - Fix double free when veth_xdp_tx() returns a positive value. - Convert xdp_xmit and xdp_redir variables into flags. Signed-off-by: Toshiaki Makita Signed-off-by: Daniel Borkmann --- drivers/net/veth.c | 119 +++++++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 110 insertions(+), 9 deletions(-) (limited to 'drivers/net/veth.c') diff --git a/drivers/net/veth.c b/drivers/net/veth.c index dbb693a7795e..9b0a7b9ab1b8 100644 --- a/drivers/net/veth.c +++ b/drivers/net/veth.c @@ -32,6 +32,10 @@ #define VETH_RING_SIZE 256 #define VETH_XDP_HEADROOM (XDP_PACKET_HEADROOM + NET_IP_ALIGN) +/* Separating two types of XDP xmit */ +#define VETH_XDP_TX BIT(0) +#define VETH_XDP_REDIR BIT(1) + struct pcpu_vstats { u64 packets; u64 bytes; @@ -45,6 +49,7 @@ struct veth_priv { struct bpf_prog *_xdp_prog; struct net_device __rcu *peer; atomic64_t dropped; + struct xdp_mem_info xdp_mem; unsigned requested_headroom; bool rx_notify_masked; struct ptr_ring xdp_ring; @@ -317,12 +322,44 @@ static int veth_xdp_xmit(struct net_device *dev, int n, return n - drops; } +static void veth_xdp_flush(struct net_device *dev) +{ + struct veth_priv *rcv_priv, *priv = netdev_priv(dev); + struct net_device *rcv; + + rcu_read_lock(); + rcv = rcu_dereference(priv->peer); + if (unlikely(!rcv)) + goto out; + + rcv_priv = netdev_priv(rcv); + /* xdp_ring is initialized on receive side? */ + if (unlikely(!rcu_access_pointer(rcv_priv->xdp_prog))) + goto out; + + __veth_xdp_flush(rcv_priv); +out: + rcu_read_unlock(); +} + +static int veth_xdp_tx(struct net_device *dev, struct xdp_buff *xdp) +{ + struct xdp_frame *frame = convert_to_xdp_frame(xdp); + + if (unlikely(!frame)) + return -EOVERFLOW; + + return veth_xdp_xmit(dev, 1, &frame, 0); +} + static struct sk_buff *veth_xdp_rcv_one(struct veth_priv *priv, - struct xdp_frame *frame) + struct xdp_frame *frame, + unsigned int *xdp_xmit) { void *hard_start = frame->data - frame->headroom; void *head = hard_start - sizeof(struct xdp_frame); int len = frame->len, delta = 0; + struct xdp_frame orig_frame; struct bpf_prog *xdp_prog; unsigned int headroom; struct sk_buff *skb; @@ -346,6 +383,29 @@ static struct sk_buff *veth_xdp_rcv_one(struct veth_priv *priv, delta = frame->data - xdp.data; len = xdp.data_end - xdp.data; break; + case XDP_TX: + orig_frame = *frame; + xdp.data_hard_start = head; + xdp.rxq->mem = frame->mem; + if (unlikely(veth_xdp_tx(priv->dev, &xdp) < 0)) { + trace_xdp_exception(priv->dev, xdp_prog, act); + frame = &orig_frame; + goto err_xdp; + } + *xdp_xmit |= VETH_XDP_TX; + rcu_read_unlock(); + goto xdp_xmit; + case XDP_REDIRECT: + orig_frame = *frame; + xdp.data_hard_start = head; + xdp.rxq->mem = frame->mem; + if (xdp_do_redirect(priv->dev, &xdp, xdp_prog)) { + frame = &orig_frame; + goto err_xdp; + } + *xdp_xmit |= VETH_XDP_REDIR; + rcu_read_unlock(); + goto xdp_xmit; default: bpf_warn_invalid_xdp_action(act); case XDP_ABORTED: @@ -370,12 +430,13 @@ err: err_xdp: rcu_read_unlock(); xdp_return_frame(frame); - +xdp_xmit: return NULL; } static struct sk_buff *veth_xdp_rcv_skb(struct veth_priv *priv, - struct sk_buff *skb) + struct sk_buff *skb, + unsigned int *xdp_xmit) { u32 pktlen, headroom, act, metalen; void *orig_data, *orig_data_end; @@ -447,6 +508,26 @@ static struct sk_buff *veth_xdp_rcv_skb(struct veth_priv *priv, switch (act) { case XDP_PASS: break; + case XDP_TX: + get_page(virt_to_page(xdp.data)); + consume_skb(skb); + xdp.rxq->mem = priv->xdp_mem; + if (unlikely(veth_xdp_tx(priv->dev, &xdp) < 0)) { + trace_xdp_exception(priv->dev, xdp_prog, act); + goto err_xdp; + } + *xdp_xmit |= VETH_XDP_TX; + rcu_read_unlock(); + goto xdp_xmit; + case XDP_REDIRECT: + get_page(virt_to_page(xdp.data)); + consume_skb(skb); + xdp.rxq->mem = priv->xdp_mem; + if (xdp_do_redirect(priv->dev, &xdp, xdp_prog)) + goto err_xdp; + *xdp_xmit |= VETH_XDP_REDIR; + rcu_read_unlock(); + goto xdp_xmit; default: bpf_warn_invalid_xdp_action(act); case XDP_ABORTED: @@ -477,9 +558,15 @@ drop: rcu_read_unlock(); kfree_skb(skb); return NULL; +err_xdp: + rcu_read_unlock(); + page_frag_free(xdp.data); +xdp_xmit: + return NULL; } -static int veth_xdp_rcv(struct veth_priv *priv, int budget) +static int veth_xdp_rcv(struct veth_priv *priv, int budget, + unsigned int *xdp_xmit) { int i, done = 0; @@ -490,10 +577,12 @@ static int veth_xdp_rcv(struct veth_priv *priv, int budget) if (!ptr) break; - if (veth_is_xdp_frame(ptr)) - skb = veth_xdp_rcv_one(priv, veth_ptr_to_xdp(ptr)); - else - skb = veth_xdp_rcv_skb(priv, ptr); + if (veth_is_xdp_frame(ptr)) { + skb = veth_xdp_rcv_one(priv, veth_ptr_to_xdp(ptr), + xdp_xmit); + } else { + skb = veth_xdp_rcv_skb(priv, ptr, xdp_xmit); + } if (skb) napi_gro_receive(&priv->xdp_napi, skb); @@ -508,9 +597,11 @@ static int veth_poll(struct napi_struct *napi, int budget) { struct veth_priv *priv = container_of(napi, struct veth_priv, xdp_napi); + unsigned int xdp_xmit = 0; int done; - done = veth_xdp_rcv(priv, budget); + xdp_set_return_frame_no_direct(); + done = veth_xdp_rcv(priv, budget, &xdp_xmit); if (done < budget && napi_complete_done(napi, done)) { /* Write rx_notify_masked before reading ptr_ring */ @@ -521,6 +612,12 @@ static int veth_poll(struct napi_struct *napi, int budget) } } + if (xdp_xmit & VETH_XDP_TX) + veth_xdp_flush(priv->dev); + if (xdp_xmit & VETH_XDP_REDIR) + xdp_do_flush_map(); + xdp_clear_return_frame_no_direct(); + return done; } @@ -567,6 +664,9 @@ static int veth_enable_xdp(struct net_device *dev) err = veth_napi_add(dev); if (err) goto err; + + /* Save original mem info as it can be overwritten */ + priv->xdp_mem = priv->xdp_rxq.mem; } rcu_assign_pointer(priv->xdp_prog, priv->_xdp_prog); @@ -584,6 +684,7 @@ static void veth_disable_xdp(struct net_device *dev) rcu_assign_pointer(priv->xdp_prog, NULL); veth_napi_del(dev); + priv->xdp_rxq.mem = priv->xdp_mem; xdp_rxq_info_unreg(&priv->xdp_rxq); } -- cgit v1.2.3-59-g8ed1b