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mptcp: Handle incoming 32-bit DATA_FIN values

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The peer may send a DATA_FIN mapping with either a 32-bit or 64-bit
sequence number. When a 32-bit sequence number is received for the
DATA_FIN, it must be expanded to 64 bits before comparing it to the
last acked sequence number. This expansion was missing.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/93
Fixes: 3721b9b646 ("mptcp: Track received DATA_FIN sequence number and add related helpers")
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Mat Martineau
2020-09-29 15:08:20 -07:00
committed by David S. Miller
parent 917944da3b
commit 1a49b2c2a5
3 changed files with 18 additions and 7 deletions
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16
net/mptcp/subflow.c
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@@ -731,7 +731,8 @@ static enum mapping_status get_mapping_status(struct sock *ssk,
if (mpext->data_fin == 1) {
if (data_len == 1) {
bool updated = mptcp_update_rcv_data_fin(msk, mpext->data_seq);
bool updated = mptcp_update_rcv_data_fin(msk, mpext->data_seq,
mpext->dsn64);
pr_debug("DATA_FIN with no payload seq=%llu", mpext->data_seq);
if (subflow->map_valid) {
/* A DATA_FIN might arrive in a DSS
@@ -748,8 +749,17 @@ static enum mapping_status get_mapping_status(struct sock *ssk,
return MAPPING_DATA_FIN;
}
} else {
mptcp_update_rcv_data_fin(msk, mpext->data_seq + data_len);
pr_debug("DATA_FIN with mapping seq=%llu", mpext->data_seq + data_len);
u64 data_fin_seq = mpext->data_seq + data_len;
/* If mpext->data_seq is a 32-bit value, data_fin_seq
* must also be limited to 32 bits.
*/
if (!mpext->dsn64)
data_fin_seq &= GENMASK_ULL(31, 0);
mptcp_update_rcv_data_fin(msk, data_fin_seq, mpext->dsn64);
pr_debug("DATA_FIN with mapping seq=%llu dsn64=%d",
data_fin_seq, mpext->dsn64);
}
/* Adjust for DATA_FIN using 1 byte of sequence space */