[PATCH 1/3] net-zerocopy: split zerocopy receive to several parts

Hao Xu
2022-01-24T09:43:36Z

Split the zerocopy receive code to several parts so that we can use them
easily in other places like io_uring.

Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
---
include/net/tcp.h | 5 ++
net/ipv4/tcp.c | 128 +++++++++++++++++++++++++++-------------------
2 files changed, 80 insertions(+), 53 deletions(-)

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 44e442bf23f9..ba0e7957bdfb 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -419,6 +419,11 @@ void tcp_data_ready(struct sock *sk);
#ifdef CONFIG_MMU
int tcp_mmap(struct file *file, struct socket *sock,
struct vm_area_struct *vma);
+int zc_receive_check(struct tcp_zerocopy_receive *zc, int *lenp,
+ char __user *optval, int __user *optlen);
+int zc_receive_update(struct sock *sk, struct tcp_zerocopy_receive *zc, int len,
+ char __user *optval, struct scm_timestamping_internal *tss,
+ int err);
#endif
void tcp_parse_options(const struct net *net, const struct sk_buff *skb,
struct tcp_options_received *opt_rx,
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 3b75836db19b..d47e3ccf7cdb 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -3936,6 +3936,76 @@ struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk,
return stats;
}

+int zc_receive_check(struct tcp_zerocopy_receive *zc, int *lenp,
+ char __user *optval, int __user *optlen)
+{
+ int len = *lenp, err;
+
+ if (get_user(len, optlen))
+ return -EFAULT;
+ if (len < 0 ||
+ len < offsetofend(struct tcp_zerocopy_receive, length))
+ return -EINVAL;
+ if (unlikely(len > sizeof(*zc))) {
+ err = check_zeroed_user(optval + sizeof(*zc),
+ len - sizeof(*zc));
+ if (err < 1)
+ return err == 0 ? -EINVAL : err;
+ len = sizeof(*zc);
+ if (put_user(len, optlen))
+ return -EFAULT;
+ }
+ if (copy_from_user(zc, optval, len))
+ return -EFAULT;
+
+ if (zc->reserved)
+ return -EINVAL;
+ if (zc->msg_flags & ~(TCP_VALID_ZC_MSG_FLAGS))
+ return -EINVAL;
+
+ *lenp = len;
+ return 0;
+}
+
+int zc_receive_update(struct sock *sk, struct tcp_zerocopy_receive *zc, int len,
+ char __user *optval, struct scm_timestamping_internal *tss,
+ int err)
+{
+ sk_defer_free_flush(sk);
+ if (len >= offsetofend(struct tcp_zerocopy_receive, msg_flags))
+ goto zerocopy_rcv_cmsg;
+ switch (len) {
+ case offsetofend(struct tcp_zerocopy_receive, msg_flags):
+ goto zerocopy_rcv_cmsg;
+ case offsetofend(struct tcp_zerocopy_receive, msg_controllen):
+ case offsetofend(struct tcp_zerocopy_receive, msg_control):
+ case offsetofend(struct tcp_zerocopy_receive, flags):
+ case offsetofend(struct tcp_zerocopy_receive, copybuf_len):
+ case offsetofend(struct tcp_zerocopy_receive, copybuf_address):
+ case offsetofend(struct tcp_zerocopy_receive, err):
+ goto zerocopy_rcv_sk_err;
+ case offsetofend(struct tcp_zerocopy_receive, inq):
+ goto zerocopy_rcv_inq;
+ case offsetofend(struct tcp_zerocopy_receive, length):
+ default:
+ goto zerocopy_rcv_out;
+ }
+zerocopy_rcv_cmsg:
+ if (zc->msg_flags & TCP_CMSG_TS)
+ tcp_zc_finalize_rx_tstamp(sk, zc, tss);
+ else
+ zc->msg_flags = 0;
+zerocopy_rcv_sk_err:
+ if (!err)
+ zc->err = sock_error(sk);
+zerocopy_rcv_inq:
+ zc->inq = tcp_inq_hint(sk);
+zerocopy_rcv_out:
+ if (!err && copy_to_user(optval, zc, len))
+ err = -EFAULT;
+ return err;
+}
+
static int do_tcp_getsockopt(struct sock *sk, int level,
int optname, char __user *optval, int __user *optlen)
{
@@ -4192,64 +4262,16 @@ static int do_tcp_getsockopt(struct sock *sk, int level,
struct tcp_zerocopy_receive zc = {};
int err;

- if (get_user(len, optlen))
- return -EFAULT;
- if (len < 0 ||
- len < offsetofend(struct tcp_zerocopy_receive, length))
- return -EINVAL;
- if (unlikely(len > sizeof(zc))) {
- err = check_zeroed_user(optval + sizeof(zc),
- len - sizeof(zc));
- if (err < 1)
- return err == 0 ? -EINVAL : err;
- len = sizeof(zc);
- if (put_user(len, optlen))
- return -EFAULT;
- }
- if (copy_from_user(&zc, optval, len))
- return -EFAULT;
- if (zc.reserved)
- return -EINVAL;
- if (zc.msg_flags & ~(TCP_VALID_ZC_MSG_FLAGS))
- return -EINVAL;
+ err = zc_receive_check(&zc, &len, optval, optlen);
+ if (err)
+ return err;
+
lock_sock(sk);
err = tcp_zerocopy_receive(sk, &zc, &tss);
err = BPF_CGROUP_RUN_PROG_GETSOCKOPT_KERN(sk, level, optname,
&zc, &len, err);
release_sock(sk);
- sk_defer_free_flush(sk);
- if (len >= offsetofend(struct tcp_zerocopy_receive, msg_flags))
- goto zerocopy_rcv_cmsg;
- switch (len) {
- case offsetofend(struct tcp_zerocopy_receive, msg_flags):
- goto zerocopy_rcv_cmsg;
- case offsetofend(struct tcp_zerocopy_receive, msg_controllen):
- case offsetofend(struct tcp_zerocopy_receive, msg_control):
- case offsetofend(struct tcp_zerocopy_receive, flags):
- case offsetofend(struct tcp_zerocopy_receive, copybuf_len):
- case offsetofend(struct tcp_zerocopy_receive, copybuf_address):
- case offsetofend(struct tcp_zerocopy_receive, err):
- goto zerocopy_rcv_sk_err;
- case offsetofend(struct tcp_zerocopy_receive, inq):
- goto zerocopy_rcv_inq;
- case offsetofend(struct tcp_zerocopy_receive, length):
- default:
- goto zerocopy_rcv_out;
- }
-zerocopy_rcv_cmsg:
- if (zc.msg_flags & TCP_CMSG_TS)
- tcp_zc_finalize_rx_tstamp(sk, &zc, &tss);
- else
- zc.msg_flags = 0;
-zerocopy_rcv_sk_err:
- if (!err)
- zc.err = sock_error(sk);
-zerocopy_rcv_inq:
- zc.inq = tcp_inq_hint(sk);
-zerocopy_rcv_out:
- if (!err && copy_to_user(optval, &zc, len))
- err = -EFAULT;
- return err;
+ return zc_receive_update(sk, &zc, len, optval, &tss, err);
}
#endif
default:
--
2.25.1