[PATCH 2/5] io_uring/net: allow filtering on IORING_OP_SOCKET data

[Jens Axboe <axboe@kernel.dk>]

Example population method for the BPF based opcode filtering. This
exposes the socket family, type, and protocol to a registered BPF
filter. This in turn enables the filter to make decisions based on
what was passed in to the IORING_OP_SOCKET request type.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 include/uapi/linux/io_uring.h |  9 ++++++++-
 io_uring/bpf_filter.c         | 10 ++++++++++
 io_uring/net.c                |  9 +++++++++
 io_uring/net.h                |  5 +++++
 4 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 768b0e7c0b57..27839318c43e 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -1121,7 +1121,14 @@ struct io_uring_bpf_ctx {
 	__u8	sqe_flags;
 	__u8	pad[6];
 	__u64	user_data;
-	__u64	resv[6];
+	union {
+		__u64	resv[6];
+		struct {
+			__u32	family;
+			__u32	type;
+			__u32	protocol;
+		} socket;
+	};
 };
 
 enum {
diff --git a/io_uring/bpf_filter.c b/io_uring/bpf_filter.c
index f63a8e9e85db..74969e9bc3b4 100644
--- a/io_uring/bpf_filter.c
+++ b/io_uring/bpf_filter.c
@@ -78,6 +78,16 @@ static void io_uring_populate_bpf_ctx(struct io_uring_bpf_ctx *bctx,
 	bctx->opcode = req->opcode;
 	bctx->sqe_flags = (__force int) req->flags & SQE_VALID_FLAGS;
 	bctx->user_data = req->cqe.user_data;
+
+	/*
+	 * Opcodes can provide a handler fo populating more data into bctx,
+	 * for filters to use.
+	 */
+	switch (req->opcode) {
+	case IORING_OP_SOCKET:
+		io_socket_bpf_populate(bctx, req);
+		break;
+	}
 }
 
 /*
diff --git a/io_uring/net.c b/io_uring/net.c
index 519ea055b761..4fcba36bd0bb 100644
--- a/io_uring/net.c
+++ b/io_uring/net.c
@@ -1699,6 +1699,15 @@ int io_accept(struct io_kiocb *req, unsigned int issue_flags)
 	return IOU_COMPLETE;
 }
 
+void io_socket_bpf_populate(struct io_uring_bpf_ctx *bctx, struct io_kiocb *req)
+{
+	struct io_socket *sock = io_kiocb_to_cmd(req, struct io_socket);
+
+	bctx->socket.family = sock->domain;
+	bctx->socket.type = sock->type;
+	bctx->socket.protocol = sock->protocol;
+}
+
 int io_socket_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
 	struct io_socket *sock = io_kiocb_to_cmd(req, struct io_socket);
diff --git a/io_uring/net.h b/io_uring/net.h
index 43e5ce5416b7..eef6b4272d01 100644
--- a/io_uring/net.h
+++ b/io_uring/net.h
@@ -44,6 +44,7 @@ int io_accept(struct io_kiocb *req, unsigned int issue_flags);
 
 int io_socket_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
 int io_socket(struct io_kiocb *req, unsigned int issue_flags);
+void io_socket_bpf_populate(struct io_uring_bpf_ctx *bctx, struct io_kiocb *req);
 
 int io_connect_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
 int io_connect(struct io_kiocb *req, unsigned int issue_flags);
@@ -64,4 +65,8 @@ void io_netmsg_cache_free(const void *entry);
 static inline void io_netmsg_cache_free(const void *entry)
 {
 }
+static inline void io_socket_bpf_populate(struct io_uring_bpf_ctx *bctx,
+					  struct io_kiocb *req)
+{
+}
 #endif
-- 
2.51.0