tls: convert to generic sk_msg interface
Convert kTLS over to make use of sk_msg interface for plaintext and
encrypted scattergather data, so it reuses all the sk_msg helpers
and data structure which later on in a second step enables to glue
this to BPF.
This also allows to remove quite a bit of open coded helpers which
are covered by the sk_msg API. Recent changes in kTLs 80ece6a03aaf
("tls: Remove redundant vars from tls record structure") and
4e6d47206c32 ("tls: Add support for inplace records encryption")
changed the data path handling a bit; while we've kept the latter
optimization intact, we had to undo the former change to better
fit the sk_msg model, hence the sg_aead_in and sg_aead_out have
been brought back and are linked into the sk_msg sgs. Now the kTLS
record contains a msg_plaintext and msg_encrypted sk_msg each.
In the original code, the zerocopy_from_iter() has been used out
of TX but also RX path. For the strparser skb-based RX path,
we've left the zerocopy_from_iter() in decrypt_internal() mostly
untouched, meaning it has been moved into tls_setup_from_iter()
with charging logic removed (as not used from RX). Given RX path
is not based on sk_msg objects, we haven't pursued setting up a
dummy sk_msg to call into sk_msg_zerocopy_from_iter(), but it
could be an option to prusue in a later step.
Joint work with John.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
diff --git a/net/core/skmsg.c b/net/core/skmsg.c
index ae2b281..56a99d0 100644
--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c
@@ -73,6 +73,45 @@ int sk_msg_alloc(struct sock *sk, struct sk_msg *msg, int len,
}
EXPORT_SYMBOL_GPL(sk_msg_alloc);
+int sk_msg_clone(struct sock *sk, struct sk_msg *dst, struct sk_msg *src,
+ u32 off, u32 len)
+{
+ int i = src->sg.start;
+ struct scatterlist *sge = sk_msg_elem(src, i);
+ u32 sge_len, sge_off;
+
+ if (sk_msg_full(dst))
+ return -ENOSPC;
+
+ while (off) {
+ if (sge->length > off)
+ break;
+ off -= sge->length;
+ sk_msg_iter_var_next(i);
+ if (i == src->sg.end && off)
+ return -ENOSPC;
+ sge = sk_msg_elem(src, i);
+ }
+
+ while (len) {
+ sge_len = sge->length - off;
+ sge_off = sge->offset + off;
+ if (sge_len > len)
+ sge_len = len;
+ off = 0;
+ len -= sge_len;
+ sk_msg_page_add(dst, sg_page(sge), sge_len, sge_off);
+ sk_mem_charge(sk, sge_len);
+ sk_msg_iter_var_next(i);
+ if (i == src->sg.end && len)
+ return -ENOSPC;
+ sge = sk_msg_elem(src, i);
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(sk_msg_clone);
+
void sk_msg_return_zero(struct sock *sk, struct sk_msg *msg, int bytes)
{
int i = msg->sg.start;