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[v4,bpf-next,05/15] xdp: Add xdp_txq_info to xdp_buff

Message ID 20200427224633.15627-6-dsahern@kernel.org
State Changes Requested
Delegated to: BPF Maintainers
Headers show
Series net: Add support for XDP in egress path | expand

Commit Message

David Ahern April 27, 2020, 10:46 p.m. UTC 
From: David Ahern <dahern@digitalocean.com>

Add xdp_txq_info as the Tx counterpart to xdp_rxq_info. At the
moment only the device is added. Other fields (queue_index)
can be added as use cases arise.

From a UAPI perspective, add egress_ifindex to xdp context.

Update the verifier to reject accesses to egress_ifindex by
rx programs.

Signed-off-by: David Ahern <dahern@digitalocean.com>
---
 include/net/xdp.h              |  5 +++++
 include/uapi/linux/bpf.h       |  2 ++
 net/core/filter.c              | 15 +++++++++++++++
 tools/include/uapi/linux/bpf.h |  2 ++
 4 files changed, 24 insertions(+)
diff mbox series

Patch

diff --git a/include/net/xdp.h b/include/net/xdp.h
index 3264fa882de3..2b85b8649201 100644
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -63,6 +63,10 @@  struct xdp_rxq_info {
 	struct xdp_mem_info mem;
 } ____cacheline_aligned; /* perf critical, avoid false-sharing */
 
+struct xdp_txq_info {
+	struct net_device *dev;
+};
+
 struct xdp_buff {
 	void *data;
 	void *data_end;
@@ -70,6 +74,7 @@  struct xdp_buff {
 	void *data_hard_start;
 	unsigned long handle;
 	struct xdp_rxq_info *rxq;
+	struct xdp_txq_info *txq;
 };
 
 struct xdp_frame {
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index c89da2c2b1f2..3166f7f2696e 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -3498,6 +3498,8 @@  struct xdp_md {
 	/* Below access go through struct xdp_rxq_info */
 	__u32 ingress_ifindex; /* rxq->dev->ifindex */
 	__u32 rx_queue_index;  /* rxq->queue_index  */
+
+	__u32 egress_ifindex;  /* txq->dev->ifindex */
 };
 
 enum sk_action {
diff --git a/net/core/filter.c b/net/core/filter.c
index 00e1941137ab..b6ab7b4dcc1f 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -6870,6 +6870,11 @@  static bool xdp_is_valid_access(int off, int size,
 		case offsetof(struct xdp_md, rx_queue_index):
 			return false;
 		}
+	} else if (prog->expected_attach_type != BPF_XDP_EGRESS) {
+		switch (off) {
+		case offsetof(struct xdp_md, egress_ifindex):
+			return false;
+		}
 	}
 
 	if (type == BPF_WRITE) {
@@ -7819,6 +7824,16 @@  static u32 xdp_convert_ctx_access(enum bpf_access_type type,
 				      offsetof(struct xdp_rxq_info,
 					       queue_index));
 		break;
+	case offsetof(struct xdp_md, egress_ifindex):
+		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct xdp_buff, txq),
+				      si->dst_reg, si->src_reg,
+				      offsetof(struct xdp_buff, txq));
+		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct xdp_txq_info, dev),
+				      si->dst_reg, si->dst_reg,
+				      offsetof(struct xdp_txq_info, dev));
+		*insn++ = BPF_LDX_MEM(BPF_W, si->dst_reg, si->dst_reg,
+				      offsetof(struct net_device, ifindex));
+		break;
 	}
 
 	return insn - insn_buf;
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index c89da2c2b1f2..3166f7f2696e 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -3498,6 +3498,8 @@  struct xdp_md {
 	/* Below access go through struct xdp_rxq_info */
 	__u32 ingress_ifindex; /* rxq->dev->ifindex */
 	__u32 rx_queue_index;  /* rxq->queue_index  */
+
+	__u32 egress_ifindex;  /* txq->dev->ifindex */
 };
 
 enum sk_action {