[RFC PATCH 3/4] net: add uring_cmd callback to TCP

Breno Leitao
2023-04-06T14:46:53Z

This is the implementation of uring_cmd for the TCP protocol. It
basically encompasses SOCKET_URING_OP_SIOCOUTQ and
SOCKET_URING_OP_SIOCINQ, which is similar to the SIOCOUTQ and SIOCINQ
ioctls.

The return value is exactly the same as the regular ioctl (tcp_ioctl()).

Signed-off-by: Breno Leitao <leitao@debian.org>
---
include/net/tcp.h | 2 ++
net/ipv4/tcp.c | 32 ++++++++++++++++++++++++++++++++
net/ipv4/tcp_ipv4.c | 1 +
3 files changed, 35 insertions(+)

diff --git a/include/net/tcp.h b/include/net/tcp.h
index db9f828e9d1e..4dfd6bd63261 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -342,6 +342,8 @@ void tcp_release_cb(struct sock *sk);
void tcp_wfree(struct sk_buff *skb);
void tcp_write_timer_handler(struct sock *sk);
void tcp_delack_timer_handler(struct sock *sk);
+int tcp_uring_cmd(struct sock *sk, struct io_uring_cmd *cmd,
+ unsigned int issue_flags);
int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg);
int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb);
void tcp_rcv_established(struct sock *sk, struct sk_buff *skb);
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 288693981b00..cf2822242e28 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -279,6 +279,7 @@
#include <linux/uaccess.h>
#include <asm/ioctls.h>
#include <net/busy_poll.h>
+#include <linux/io_uring.h>

/* Track pending CMSGs. */
enum {
@@ -596,6 +597,37 @@ __poll_t tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
}
EXPORT_SYMBOL(tcp_poll);

+int tcp_uring_cmd(struct sock *sk, struct io_uring_cmd *cmd,
+ unsigned int issue_flags)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+ bool slow;
+ int ret;
+
+ switch (cmd->sqe->cmd_op) {
+ case SOCKET_URING_OP_SIOCINQ:
+ if (sk->sk_state == TCP_LISTEN)
+ return -EINVAL;
+
+ slow = lock_sock_fast(sk);
+ ret = tcp_inq(sk);
+ unlock_sock_fast(sk, slow);
+ return ret;
+ case SOCKET_URING_OP_SIOCOUTQ:
+ if (sk->sk_state == TCP_LISTEN)
+ return -EINVAL;
+
+ if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
+ ret = 0;
+ else
+ ret = READ_ONCE(tp->write_seq) - tp->snd_una;
+ return ret;
+ default:
+ return -ENOIOCTLCMD;
+ }
+}
+EXPORT_SYMBOL_GPL(tcp_uring_cmd);
+
int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
{
struct tcp_sock *tp = tcp_sk(sk);
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index ea370afa70ed..900081fa2e1a 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -3103,6 +3103,7 @@ struct proto tcp_prot = {
.disconnect = tcp_disconnect,
.accept = inet_csk_accept,
.ioctl = tcp_ioctl,
+ .uring_cmd = tcp_uring_cmd,
.init = tcp_v4_init_sock,
.destroy = tcp_v4_destroy_sock,
.shutdown = tcp_shutdown,
--
2.34.1