bpf: helper to pop data from messages
This adds a BPF SK_MSG program helper so that we can pop data from a
msg. We use this to pop metadata from a previous push data call.
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index 7b1af8b..d4ecc66 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -687,6 +687,7 @@ static int bpf_exec_tx_verdict(struct sk_msg *msg, struct sock *sk,
struct sock *sk_redir;
struct tls_rec *rec;
int err = 0, send;
+ u32 delta = 0;
bool enospc;
psock = sk_psock_get(sk);
@@ -694,8 +695,14 @@ static int bpf_exec_tx_verdict(struct sk_msg *msg, struct sock *sk,
return tls_push_record(sk, flags, record_type);
more_data:
enospc = sk_msg_full(msg);
- if (psock->eval == __SK_NONE)
+ if (psock->eval == __SK_NONE) {
+ delta = msg->sg.size;
psock->eval = sk_psock_msg_verdict(sk, psock, msg);
+ if (delta < msg->sg.size)
+ delta -= msg->sg.size;
+ else
+ delta = 0;
+ }
if (msg->cork_bytes && msg->cork_bytes > msg->sg.size &&
!enospc && !full_record) {
err = -ENOSPC;
@@ -743,7 +750,7 @@ static int bpf_exec_tx_verdict(struct sk_msg *msg, struct sock *sk,
msg->apply_bytes -= send;
if (msg->sg.size == 0)
tls_free_open_rec(sk);
- *copied -= send;
+ *copied -= (send + delta);
err = -EACCES;
}