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From: David Ahern <dsahern@kernel.org>
To: netdev@vger.kernel.org
Cc: bpf@vger.kernel.org, davem@davemloft.net, kuba@kernel.org,
	brouer@redhat.com, toke@redhat.com, lorenzo@kernel.org,
	daniel@iogearbox.net, john.fastabend@gmail.com, ast@kernel.org,
	kafai@fb.com, songliubraving@fb.com, yhs@fb.com, andriin@fb.com,
	dsahern@gmail.com, David Ahern <dsahern@kernel.org>
Subject: [PATCH v3 bpf-next 3/5] xdp: Add xdp_txq_info to xdp_buff
Date: Thu, 28 May 2020 23:20:55 -0600	[thread overview]
Message-ID: <20200529052057.69378-4-dsahern@kernel.org> (raw)
In-Reply-To: <20200529052057.69378-1-dsahern@kernel.org>

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 for
bpf programs to see the Tx device.

Update the verifier to only allow accesses to egress_ifindex by
XDP programs with BPF_XDP_DEVMAP expected attach type.

Signed-off-by: David Ahern <dsahern@kernel.org>
---
 include/net/xdp.h              |  5 +++++
 include/uapi/linux/bpf.h       |  2 ++
 kernel/bpf/devmap.c            |  3 +++
 net/core/filter.c              | 17 +++++++++++++++++
 tools/include/uapi/linux/bpf.h |  2 ++
 5 files changed, 29 insertions(+)

diff --git a/include/net/xdp.h b/include/net/xdp.h
index 90f11760bd12..d54022959491 100644
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -61,12 +61,17 @@ 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;
 	void *data_meta;
 	void *data_hard_start;
 	struct xdp_rxq_info *rxq;
+	struct xdp_txq_info *txq;
 	u32 frame_sz; /* frame size to deduce data_hard_end/reserved tailroom*/
 };
 
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 02177049cf66..61ae81bf67de 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -3624,6 +3624,8 @@ 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 */
 };
 
 /* DEVMAP values */
diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index 3152151d3bb8..defdd22caa4b 100644
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -467,8 +467,11 @@ static struct xdp_buff *dev_map_run_prog(struct net_device *dev,
 					 struct xdp_buff *xdp,
 					 struct bpf_prog *xdp_prog)
 {
+	struct xdp_txq_info txq = { .dev = dev };
 	u32 act;
 
+	xdp->txq = &txq;
+
 	act = bpf_prog_run_xdp(xdp_prog, xdp);
 	switch (act) {
 	case XDP_PASS:
diff --git a/net/core/filter.c b/net/core/filter.c
index a6fc23447f12..2e9dbfd8e60c 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -7014,6 +7014,13 @@ static bool xdp_is_valid_access(int off, int size,
 				const struct bpf_prog *prog,
 				struct bpf_insn_access_aux *info)
 {
+	if (prog->expected_attach_type != BPF_XDP_DEVMAP) {
+		switch (off) {
+		case offsetof(struct xdp_md, egress_ifindex):
+			return false;
+		}
+	}
+
 	if (type == BPF_WRITE) {
 		if (bpf_prog_is_dev_bound(prog->aux)) {
 			switch (off) {
@@ -7967,6 +7974,16 @@ 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 02177049cf66..61ae81bf67de 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -3624,6 +3624,8 @@ 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 */
 };
 
 /* DEVMAP values */
-- 
2.21.1 (Apple Git-122.3)


  parent reply	other threads:[~2020-05-29  5:21 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-29  5:20 [PATCH v3 bpf-next 0/5] bpf: Add support for XDP programs in DEVMAP entries David Ahern
2020-05-29  5:20 ` [PATCH v3 bpf-next 1/5] devmap: Formalize map value as a named struct David Ahern
2020-05-29  8:22   ` Jesper Dangaard Brouer
2020-05-29 15:36     ` David Ahern
2020-05-29 16:02       ` Jesper Dangaard Brouer
2020-05-29  5:20 ` [PATCH v3 bpf-next 2/5] bpf: Add support to attach bpf program to a devmap entry David Ahern
2020-05-29  5:20 ` David Ahern [this message]
2020-05-29  5:20 ` [PATCH v3 bpf-next 4/5] libbpf: Add SEC name for xdp programs attached to device map David Ahern
2020-05-29  5:20 ` [PATCH v3 bpf-next 5/5] selftest: Add tests for XDP programs in devmap entries David Ahern
2020-05-29 16:45   ` Toke Høiland-Jørgensen
2020-05-29 16:48     ` David Ahern
2020-05-29 16:58       ` Toke Høiland-Jørgensen
2020-05-29 16:46 ` [PATCH v3 bpf-next 0/5] bpf: Add support for XDP programs in DEVMAP entries Toke Høiland-Jørgensen

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