@@ -1139,7 +1139,6 @@ static enum mapping_status get_mapping_status(struct sock *ssk,
if (data_len == 0) {
pr_debug("infinite mapping received\n");
MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPRX);
- subflow->map_data_len = 0;
return MAPPING_INVALID;
}
@@ -1298,18 +1297,6 @@ static void subflow_sched_work_if_closed(struct mptcp_sock *msk, struct sock *ss
mptcp_schedule_work(sk);
}
-static bool subflow_can_fallback(struct mptcp_subflow_context *subflow)
-{
- struct mptcp_sock *msk = mptcp_sk(subflow->conn);
-
- if (subflow->mp_join)
- return false;
- else if (READ_ONCE(msk->csum_enabled))
- return !subflow->valid_csum_seen;
- else
- return READ_ONCE(msk->allow_infinite_fallback);
-}
-
static void mptcp_subflow_fail(struct mptcp_sock *msk, struct sock *ssk)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
@@ -1405,7 +1392,7 @@ static bool subflow_check_data_avail(struct sock *ssk)
return true;
}
- if (!subflow_can_fallback(subflow) && subflow->map_data_len) {
+ if (!READ_ONCE(msk->allow_infinite_fallback)) {
/* fatal protocol error, close the socket.
* subflow_error_report() will introduce the appropriate barriers
*/
Before this patch, if the checksum was not used, the subflow was only reset if map_data_len was != 0. If there were no MPTCP options or an invalid mapping, map_data_len was not set to the data len, and then the subflow was not reset as it should have been, leaving the MPTCP connection in a wrong fallback mode. This map_data_len condition has been introduced to handle the reception of the infinite mapping. Instead, a new dedicated mapping error could have been returned and treated as a special case. However, the commit 31bf11de146c ("mptcp: introduce MAPPING_BAD_CSUM") has been introduced by Paolo Abeni soon after, and backported later on to stable. It better handle the csum case, and it means the exception for valid_csum_seen in subflow_can_fallback(), plus this one for the infinite mapping in subflow_check_data_avail(), are no longer needed. In other words, the code can be simplified there: a fallback should only be done if msk->allow_infinite_fallback is set. This boolean is set to false once MPTCP-specific operations acting on the whole MPTCP connection vs the initial path have been done, e.g. a second path has been created, or an MPTCP re-injection -- yes, possible even with a single subflow. The subflow_can_fallback() helper can then be dropped, and replaced by this single condition. This also makes the code clearer: a fallback should only be done if it is possible to do so. While at it, no need to set map_data_len to 0 in get_mapping_status() for the infinite mapping case: it will be set to skb->len just after, at the end of subflow_check_data_avail(), and not read in between. Fixes: f8d4bcacff3b ("mptcp: infinite mapping receiving") Reported-by: Chester A. Unal <chester.a.unal@xpedite-tech.com> Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/544 Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> --- Notes: - v2: - Squash previous patches 1 and 2, and drop csum case from subflow_can_fallback (Paolo). - v2 is quite different, Chester's Tested-by tag has not been added. --- net/mptcp/subflow.c | 15 +-------------- 1 file changed, 1 insertion(+), 14 deletions(-)