[PATCH v5 bpf-next 07/11] net: Support xdp in the Tx path for xdp_frames
flat view
STALE2356d
From: David Ahern <dsahern@kernel.org>
Date: 2020-05-13 01:46:21
Subsystem:
bpf [general] (safe dynamic programs and tools), networking drivers, networking [general], the rest, xdp (express data path) · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Jesper Dangaard Brouer, John Fastabend
Revision v5 (5 revisions archived).
Revisions (5)
From: David Ahern <redacted> Add support to run Tx path program on xdp_frames by adding a hook to bq_xmit_all before xdp_frames are passed to ndo_xdp_xmit for the device. If an xdp_frame is dropped by the program, it is removed from the xdp_frames array with subsequent entries moved up. Signed-off-by: David Ahern <redacted> --- include/linux/netdevice.h | 2 ++ kernel/bpf/devmap.c | 19 +++++++--- net/core/dev.c | 74 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 90 insertions(+), 5 deletions(-)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 651baeb36729..042190df23d5 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h@@ -3717,6 +3717,8 @@ static inline void dev_consume_skb_any(struct sk_buff *skb) void generic_xdp_tx(struct sk_buff *skb, struct bpf_prog *xdp_prog); int do_xdp_generic(struct bpf_prog *xdp_prog, struct sk_buff *skb); +unsigned int do_xdp_egress(struct net_device *dev, struct xdp_frame **frames, + unsigned int count); int netif_rx(struct sk_buff *skb); int netif_rx_ni(struct sk_buff *skb); int netif_receive_skb(struct sk_buff *skb);
diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index a51d9fb7a359..513dec5f67b9 100644
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c@@ -321,24 +321,33 @@ static int bq_xmit_all(struct xdp_dev_bulk_queue *bq, u32 flags) { struct net_device *dev = bq->dev; int sent = 0, drops = 0, err = 0; + unsigned int count = bq->count; int i; - if (unlikely(!bq->count)) + if (unlikely(!count)) return 0; - for (i = 0; i < bq->count; i++) { + for (i = 0; i < count; i++) { struct xdp_frame *xdpf = bq->q[i]; prefetch(xdpf); } - sent = dev->netdev_ops->ndo_xdp_xmit(dev, bq->count, bq->q, flags); + if (static_branch_unlikely(&xdp_egress_needed_key)) { + count = do_xdp_egress(dev, bq->q, count); + drops += bq->count - count; + /* all frames consumed by the xdp program? */ + if (!count) + goto out; + } + + sent = dev->netdev_ops->ndo_xdp_xmit(dev, count, bq->q, flags); if (sent < 0) { err = sent; sent = 0; goto error; } - drops = bq->count - sent; + drops += count - sent; out: bq->count = 0;
@@ -350,7 +359,7 @@ static int bq_xmit_all(struct xdp_dev_bulk_queue *bq, u32 flags) /* If ndo_xdp_xmit fails with an errno, no frames have been * xmit'ed and it's our responsibility to them free all. */ - for (i = 0; i < bq->count; i++) { + for (i = 0; i < count; i++) { struct xdp_frame *xdpf = bq->q[i]; xdp_return_frame_rx_napi(xdpf);
diff --git a/net/core/dev.c b/net/core/dev.c
index 97954f835ceb..e6a737b84768 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c@@ -4673,6 +4673,80 @@ int do_xdp_generic(struct bpf_prog *xdp_prog, struct sk_buff *skb) } EXPORT_SYMBOL_GPL(do_xdp_generic); +static u32 __xdp_egress_frame(struct net_device *dev, + struct bpf_prog *xdp_prog, + struct xdp_frame *xdp_frame, + struct xdp_txq_info *txq) +{ + struct xdp_buff xdp; + u32 act; + + xdp.data_hard_start = xdp_frame->data - xdp_frame->headroom + - sizeof(*xdp_frame); + xdp.data = xdp_frame->data; + xdp.data_end = xdp.data + xdp_frame->len; + xdp.data_meta = xdp.data - xdp_frame->metasize; + xdp.txq = txq; + + act = bpf_prog_run_xdp(xdp_prog, &xdp); + switch (act) { + case XDP_DROP: + fallthrough; + case XDP_PASS: + break; + case XDP_TX: + fallthrough; + case XDP_REDIRECT: + fallthrough; + default: + bpf_warn_invalid_xdp_action(act); + fallthrough; + case XDP_ABORTED: + trace_xdp_exception(dev, xdp_prog, act); + act = XDP_DROP; + break; + } + + /* if not dropping frame, readjust pointers in case + * program made changes to the buffer + */ + if (act != XDP_DROP) { + if (unlikely(!update_xdp_frame(&xdp, xdp_frame))) + return XDP_DROP; + } + + return act; +} + +unsigned int do_xdp_egress(struct net_device *dev, struct xdp_frame **frames, + unsigned int count) +{ + struct bpf_prog *xdp_prog; + + xdp_prog = rcu_dereference(dev->xdp_egress_prog); + if (xdp_prog) { + struct xdp_txq_info txq = { .dev = dev }; + unsigned int i, j; + u32 act; + + for (i = 0, j = 0; i < count; i++) { + struct xdp_frame *frame = frames[i]; + + act = __xdp_egress_frame(dev, xdp_prog, frame, &txq); + if (act == XDP_DROP) { + xdp_return_frame_rx_napi(frame); + continue; + } + + frames[j] = frame; + j++; + } + count = j; + } + + return count; +} + static int netif_rx_internal(struct sk_buff *skb) { int ret;
--
2.21.1 (Apple Git-122.3)