[PATCH v4 08/10] io_uring/cmd: Introduce SOCKET_URING_OP_GETSOCKOPT

Breno Leitao
2023-09-04T16:25:58Z

Add support for getsockopt command (SOCKET_URING_OP_GETSOCKOPT), where
level is SOL_SOCKET. This is leveraging the sockptr_t infrastructure,
where a sockptr_t is either userspace or kernel space, and handled as
such.

Differently from the getsockopt(2), the optlen field is not a userspace
pointers. In getsockopt(2), userspace provides optlen pointer, which is
overwritten by the kernel. In this implementation, userspace passes a
u32, and the new value is returned in cqe->res. I.e., optlen is not a
pointer.

Important to say that userspace needs to keep the pointer alive until
the CQE is completed.

Signed-off-by: Breno Leitao <leitao@debian.org>
---
include/uapi/linux/io_uring.h | 7 +++++++
io_uring/uring_cmd.c | 28 ++++++++++++++++++++++++++++
2 files changed, 35 insertions(+)

diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 8e61f8b7c2ce..29efa02a4dcb 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -43,6 +43,10 @@ struct io_uring_sqe {
union {
__u64 addr; /* pointer to buffer or iovecs */
__u64 splice_off_in;
+ struct {
+ __u32 level;
+ __u32 optname;
+ };
};
__u32 len; /* buffer size or number of iovecs */
union {
@@ -79,6 +83,7 @@ struct io_uring_sqe {
union {
__s32 splice_fd_in;
__u32 file_index;
+ __u32 optlen;
struct {
__u16 addr_len;
__u16 __pad3[1];
@@ -89,6 +94,7 @@ struct io_uring_sqe {
__u64 addr3;
__u64 __pad2[1];
};
+ __u64 optval;
/*
* If the ring is initialized with IORING_SETUP_SQE128, then
* this field is used for 80 bytes of arbitrary command data
@@ -734,6 +740,7 @@ struct io_uring_recvmsg_out {
enum {
SOCKET_URING_OP_SIOCINQ = 0,
SOCKET_URING_OP_SIOCOUTQ,
+ SOCKET_URING_OP_GETSOCKOPT,
};

#ifdef __cplusplus
diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c
index 6a91e1af7d05..c373e05ba9ce 100644
--- a/io_uring/uring_cmd.c
+++ b/io_uring/uring_cmd.c
@@ -167,6 +167,32 @@ int io_uring_cmd_import_fixed(u64 ubuf, unsigned long len, int rw,
}
EXPORT_SYMBOL_GPL(io_uring_cmd_import_fixed);

+INDIRECT_CALLABLE_DECLARE(bool tcp_bpf_bypass_getsockopt(int level,
+ int optname));
+static inline int io_uring_cmd_getsockopt(struct socket *sock,
+ struct io_uring_cmd *cmd,
+ unsigned int issue_flags)
+{
+ void __user *optval = u64_to_user_ptr(READ_ONCE(cmd->sqe->optval));
+ bool compat = !!(issue_flags & IO_URING_F_COMPAT);
+ int optlen = READ_ONCE(cmd->sqe->optlen);
+ int optname = READ_ONCE(cmd->sqe->optname);
+ int level = READ_ONCE(cmd->sqe->level);
+ int err;
+
+ if (level != SOL_SOCKET)
+ return -EOPNOTSUPP;
+
+ err = do_sock_getsockopt(sock, compat, level, optname,
+ USER_SOCKPTR(optval),
+ KERNEL_SOCKPTR(&optlen));
+ if (err)
+ return err;
+
+ /* On success, return optlen */
+ return optlen;
+}
+
#if defined(CONFIG_NET)
int io_uring_cmd_sock(struct io_uring_cmd *cmd, unsigned int issue_flags)
{
@@ -189,6 +215,8 @@ int io_uring_cmd_sock(struct io_uring_cmd *cmd, unsigned int issue_flags)
if (ret)
return ret;
return arg;
+ case SOCKET_URING_OP_GETSOCKOPT:
+ return io_uring_cmd_getsockopt(sock, cmd, issue_flags);
default:
return -EOPNOTSUPP;
}
--
2.34.1