From 87b11e0638c3dbf029a7c9020f8a779062db58fc Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Mon, 3 Jun 2019 15:17:00 -0700 Subject: [PATCH] net/tls: remove false positive warning It's possible that TCP stack will decide to retransmit a packet right when that packet's data gets acked, especially in presence of packet reordering. This means that packets may be in flight, even though tls_device code has already freed their record state. Make fill_sg_in() and in turn tls_sw_fallback() not generate a warning in that case, and quietly proceed to drop such frames. Make the exit path from tls_sw_fallback() drop monitor friendly, for users to be able to troubleshoot dropped retransmissions. Signed-off-by: Jakub Kicinski Reviewed-by: Dirk van der Merwe Signed-off-by: David S. Miller --- Documentation/networking/tls-offload.rst | 19 ------------------- net/tls/tls_device_fallback.c | 6 ++++-- 2 files changed, 4 insertions(+), 21 deletions(-) diff --git a/Documentation/networking/tls-offload.rst b/Documentation/networking/tls-offload.rst index cb85af5..eb7c9b8 100644 --- a/Documentation/networking/tls-offload.rst +++ b/Documentation/networking/tls-offload.rst @@ -379,7 +379,6 @@ by the driver: but did not arrive in the expected order * ``tx_tls_drop_no_sync_data`` - number of TX packets dropped because they arrived out of order and associated record could not be found - (see also :ref:`pre_tls_data`) Notable corner cases, exceptions and additional requirements ============================================================ @@ -462,21 +461,3 @@ Redirects leak clear text In the RX direction, if segment has already been decrypted by the device and it gets redirected or mirrored - clear text will be transmitted out. - -.. _pre_tls_data: - -Transmission of pre-TLS data ----------------------------- - -User can enqueue some already encrypted and framed records before enabling -``ktls`` on the socket. Those records have to get sent as they are. This is -perfectly easy to handle in the software case - such data will be waiting -in the TCP layer, TLS ULP won't see it. In the offloaded case when pre-queued -segment reaches transmission point it appears to be out of order (before the -expected TCP sequence number) and the stack does not have a record information -associated. - -All segments without record information cannot, however, be assumed to be -pre-queued data, because a race condition exists between TCP stack queuing -a retransmission, the driver seeing the retransmission and TCP ACK arriving -for the retransmitted data. diff --git a/net/tls/tls_device_fallback.c b/net/tls/tls_device_fallback.c index c3a5fe6..5a087e1 100644 --- a/net/tls/tls_device_fallback.c +++ b/net/tls/tls_device_fallback.c @@ -240,7 +240,6 @@ static int fill_sg_in(struct scatterlist *sg_in, record = tls_get_record(ctx, tcp_seq, rcd_sn); if (!record) { spin_unlock_irqrestore(&ctx->lock, flags); - WARN(1, "Record not found for seq %u\n", tcp_seq); return -EINVAL; } @@ -409,7 +408,10 @@ put_sg: put_page(sg_page(&sg_in[--resync_sgs])); kfree(sg_in); free_orig: - kfree_skb(skb); + if (nskb) + consume_skb(skb); + else + kfree_skb(skb); return nskb; } -- 2.7.4