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authorPaolo Abeni <pabeni@redhat.com>2020-11-03 11:05:05 -0800
committerJakub Kicinski <kuba@kernel.org>2020-11-04 17:45:53 -0800
commit5a369ca64364b49caff424d2f988901bc7658b6d (patch)
tree4af5d3c6d1086f2d64adde122e2b780eb326011f /net/mptcp
parent65f49fe72f9e4063b96c78de62f3ff9a3384164e (diff)
tcp: propagate MPTCP skb extensions on xmit splits
When the TCP stack splits a packet on the write queue, the tail half currently lose the associated skb extensions, and will not carry the DSM on the wire. The above does not cause functional problems and is allowed by the RFC, but interact badly with GRO and RX coalescing, as possible candidates for aggregation will carry different TCP options. This change tries to improve the MPTCP behavior, propagating the skb extensions on split. Additionally, we must prevent the MPTCP stack from updating the mapping after the split occur: that will both violate the RFC and fool the reader. Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/mptcp')
-rw-r--r--net/mptcp/protocol.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index f5bacfc55006..25d12183d1ca 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -771,8 +771,11 @@ static bool mptcp_skb_can_collapse_to(u64 write_seq,
if (!tcp_skb_can_collapse_to(skb))
return false;
- /* can collapse only if MPTCP level sequence is in order */
- return mpext && mpext->data_seq + mpext->data_len == write_seq;
+ /* can collapse only if MPTCP level sequence is in order and this
+ * mapping has not been xmitted yet
+ */
+ return mpext && mpext->data_seq + mpext->data_len == write_seq &&
+ !mpext->frozen;
}
static bool mptcp_frag_can_collapse_to(const struct mptcp_sock *msk,