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mptcp: more DATA FIN fixes 

Currently data fin on data packet are not handled properly:
the 'rcv_data_fin_seq' field is interpreted as the last
sequence number carrying a valid data, but for data fin
packet with valid maps we currently store map_seq + map_len,
that is, the next value.

The 'write_seq' fields carries instead the value subseguent
to the last valid byte, so in mptcp_write_data_fin() we
never detect correctly the last DSS map.

Fixes: 7279da6145 ("mptcp: Use MPTCP-level flag for sending DATA_FIN")
Fixes: 1a49b2c2a5 ("mptcp: Handle incoming 32-bit DATA_FIN values")
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Paolo Abeni 2020-10-05 12:01:06 +02:00 committed by David S. Miller
parent c88c5ed75f
commit 017512a07e
2 changed files with 6 additions and 6 deletions
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10
net/mptcp/options.c
View File

@ -451,7 +451,10 @@ static bool mptcp_established_options_mp(struct sock *sk, struct sk_buff *skb,
static void mptcp_write_data_fin(struct mptcp_subflow_context *subflow,
struct sk_buff *skb, struct mptcp_ext *ext)
{
u64 data_fin_tx_seq = READ_ONCE(mptcp_sk(subflow->conn)->write_seq);
/* The write_seq value has already been incremented, so the actual
* sequence number for the DATA_FIN is one less.
*/
u64 data_fin_tx_seq = READ_ONCE(mptcp_sk(subflow->conn)->write_seq) - 1;
if (!ext->use_map || !skb->len) {
/* RFC6824 requires a DSS mapping with specific values
@ -460,10 +463,7 @@ static void mptcp_write_data_fin(struct mptcp_subflow_context *subflow,
ext->data_fin = 1;
ext->use_map = 1;
ext->dsn64 = 1;
/* The write_seq value has already been incremented, so
* the actual sequence number for the DATA_FIN is one less.
*/
ext->data_seq = data_fin_tx_seq - 1;
ext->data_seq = data_fin_tx_seq;
ext->subflow_seq = 0;
ext->data_len = 1;
} else if (ext->data_seq + ext->data_len == data_fin_tx_seq) {

2
net/mptcp/subflow.c
View File

@ -749,7 +749,7 @@ static enum mapping_status get_mapping_status(struct sock *ssk,
return MAPPING_DATA_FIN;
}
} else {
u64 data_fin_seq = mpext->data_seq + data_len;
u64 data_fin_seq = mpext->data_seq + data_len - 1;
/* If mpext->data_seq is a 32-bit value, data_fin_seq
* must also be limited to 32 bits.