csum: bad encoding #275
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intel-lab-lkp
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May 10, 2022
RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see multipath-tcp/mptcp_net-next#275), this allows the connection to proceed as TCP rather than reset. Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
intel-lab-lkp
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May 11, 2022
RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see multipath-tcp/mptcp_net-next#275), this allows the connection to proceed as TCP rather than reset. v2: add a helper function for checking whether a subflow is fallback-capable. Acked-by: Paolo Abeni <pabeni@redhat.com> Fixes: dd8bcd1 ("mptcp: validate the data checksum") Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
matttbe
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May 14, 2022
RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see #275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
matttbe
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May 14, 2022
RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see #275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
matttbe
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May 14, 2022
RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see #275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
matttbe
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May 14, 2022
RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see #275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
matttbe
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May 14, 2022
RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see #275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
matttbe
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May 16, 2022
RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see #275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
matttbe
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May 16, 2022
RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see #275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
matttbe
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RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see #275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
matttbe
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RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see #275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
matttbe
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RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see #275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
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Some context from the mailing list: Patch fixing little-endian csum byte order: https://lore.kernel.org/mptcp/595f104803a212df58db6d20f84947325b33a9d6.1652196378.git.pabeni@redhat.com/ Patch allowing fallback instead of connection reset on first checksum failure: https://lore.kernel.org/mptcp/20220511235137.431538-1-mathew.j.martineau@linux.intel.com/ Both of those are in the export-net branch now. Some mixed-endian testing from @darkwrat: https://lore.kernel.org/mptcp/3c85fe48-69fe-0655-2146-a4424e02f185@internet.ru/ |
jenkins-tessares
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RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see #275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
matttbe
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RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see #275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
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I also confirmed interop of the fixed code with the mptcp_trunk kernel, both running on little-endian machines. |
intel-lab-lkp
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May 17, 2022
The MPTCP code typecasts the checksum value to u16 and then converts it to big endian while storing the value into the MPTCP option. As a result, the wire encoding for little endian host is wrong, and that causes interoperabilty interoperability issues with other implementation or host with different endianness. Address the issue writing in the packet the unmodified __sum16 value. MPTCP checksum is disabled by default, interoperating with systems with bad mptcp-level csum encoding should cause fallback to TCP. Closes: multipath-tcp/mptcp_net-next#275 Fixes: c5b39e2 ("mptcp: send out checksum for DSS") Fixes: 390b95a ("mptcp: receive checksum for DSS") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
intel-lab-lkp
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RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see multipath-tcp/mptcp_net-next#275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
ammarfaizi2
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The MPTCP code typecasts the checksum value to u16 and then converts it to big endian while storing the value into the MPTCP option. As a result, the wire encoding for little endian host is wrong, and that causes interoperabilty interoperability issues with other implementation or host with different endianness. Address the issue writing in the packet the unmodified __sum16 value. MPTCP checksum is disabled by default, interoperating with systems with bad mptcp-level csum encoding should cause fallback to TCP. Closes: multipath-tcp/mptcp_net-next#275 Fixes: c5b39e2 ("mptcp: send out checksum for DSS") Fixes: 390b95a ("mptcp: receive checksum for DSS") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
ammarfaizi2
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RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see multipath-tcp/mptcp_net-next#275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
matttbe
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RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see #275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
matttbe
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RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see #275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
matttbe
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RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see #275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
matttbe
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RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see #275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
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Patches have been applied in our tree and already in -net (soon in Linus' tree) |
ammarfaizi2
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[ Upstream commit ba2c89e ] The MPTCP code typecasts the checksum value to u16 and then converts it to big endian while storing the value into the MPTCP option. As a result, the wire encoding for little endian host is wrong, and that causes interoperabilty interoperability issues with other implementation or host with different endianness. Address the issue writing in the packet the unmodified __sum16 value. MPTCP checksum is disabled by default, interoperating with systems with bad mptcp-level csum encoding should cause fallback to TCP. Closes: multipath-tcp/mptcp_net-next#275 Fixes: c5b39e2 ("mptcp: send out checksum for DSS") Fixes: 390b95a ("mptcp: receive checksum for DSS") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
ammarfaizi2
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[ Upstream commit ba2c89e ] The MPTCP code typecasts the checksum value to u16 and then converts it to big endian while storing the value into the MPTCP option. As a result, the wire encoding for little endian host is wrong, and that causes interoperabilty interoperability issues with other implementation or host with different endianness. Address the issue writing in the packet the unmodified __sum16 value. MPTCP checksum is disabled by default, interoperating with systems with bad mptcp-level csum encoding should cause fallback to TCP. Closes: multipath-tcp/mptcp_net-next#275 Fixes: c5b39e2 ("mptcp: send out checksum for DSS") Fixes: 390b95a ("mptcp: receive checksum for DSS") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
ammarfaizi2
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[ Upstream commit ae66fb2 ] RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see multipath-tcp/mptcp_net-next#275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
ammarfaizi2
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May 23, 2022
[ Upstream commit ba2c89e ] The MPTCP code typecasts the checksum value to u16 and then converts it to big endian while storing the value into the MPTCP option. As a result, the wire encoding for little endian host is wrong, and that causes interoperabilty interoperability issues with other implementation or host with different endianness. Address the issue writing in the packet the unmodified __sum16 value. MPTCP checksum is disabled by default, interoperating with systems with bad mptcp-level csum encoding should cause fallback to TCP. Closes: multipath-tcp/mptcp_net-next#275 Fixes: c5b39e2 ("mptcp: send out checksum for DSS") Fixes: 390b95a ("mptcp: receive checksum for DSS") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
ammarfaizi2
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May 23, 2022
[ Upstream commit ae66fb2 ] RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see multipath-tcp/mptcp_net-next#275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
ammarfaizi2
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May 25, 2022
[ Upstream commit ba2c89e ] The MPTCP code typecasts the checksum value to u16 and then converts it to big endian while storing the value into the MPTCP option. As a result, the wire encoding for little endian host is wrong, and that causes interoperabilty interoperability issues with other implementation or host with different endianness. Address the issue writing in the packet the unmodified __sum16 value. MPTCP checksum is disabled by default, interoperating with systems with bad mptcp-level csum encoding should cause fallback to TCP. Closes: multipath-tcp/mptcp_net-next#275 Fixes: c5b39e2 ("mptcp: send out checksum for DSS") Fixes: 390b95a ("mptcp: receive checksum for DSS") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
ammarfaizi2
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May 25, 2022
[ Upstream commit ae66fb2 ] RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see multipath-tcp/mptcp_net-next#275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
ammarfaizi2
pushed a commit
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May 25, 2022
[ Upstream commit ba2c89e ] The MPTCP code typecasts the checksum value to u16 and then converts it to big endian while storing the value into the MPTCP option. As a result, the wire encoding for little endian host is wrong, and that causes interoperabilty interoperability issues with other implementation or host with different endianness. Address the issue writing in the packet the unmodified __sum16 value. MPTCP checksum is disabled by default, interoperating with systems with bad mptcp-level csum encoding should cause fallback to TCP. Closes: multipath-tcp/mptcp_net-next#275 Fixes: c5b39e2 ("mptcp: send out checksum for DSS") Fixes: 390b95a ("mptcp: receive checksum for DSS") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
ammarfaizi2
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May 25, 2022
[ Upstream commit ae66fb2 ] RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see multipath-tcp/mptcp_net-next#275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
ammarfaizi2
pushed a commit
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that referenced
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May 25, 2022
[ Upstream commit ba2c89e ] The MPTCP code typecasts the checksum value to u16 and then converts it to big endian while storing the value into the MPTCP option. As a result, the wire encoding for little endian host is wrong, and that causes interoperabilty interoperability issues with other implementation or host with different endianness. Address the issue writing in the packet the unmodified __sum16 value. MPTCP checksum is disabled by default, interoperating with systems with bad mptcp-level csum encoding should cause fallback to TCP. Closes: multipath-tcp/mptcp_net-next#275 Fixes: c5b39e2 ("mptcp: send out checksum for DSS") Fixes: 390b95a ("mptcp: receive checksum for DSS") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
ammarfaizi2
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May 25, 2022
[ Upstream commit ae66fb2 ] RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see multipath-tcp/mptcp_net-next#275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
ammarfaizi2
pushed a commit
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May 25, 2022
[ Upstream commit ba2c89e ] The MPTCP code typecasts the checksum value to u16 and then converts it to big endian while storing the value into the MPTCP option. As a result, the wire encoding for little endian host is wrong, and that causes interoperabilty interoperability issues with other implementation or host with different endianness. Address the issue writing in the packet the unmodified __sum16 value. MPTCP checksum is disabled by default, interoperating with systems with bad mptcp-level csum encoding should cause fallback to TCP. Closes: multipath-tcp/mptcp_net-next#275 Fixes: c5b39e2 ("mptcp: send out checksum for DSS") Fixes: 390b95a ("mptcp: receive checksum for DSS") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
ammarfaizi2
pushed a commit
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May 25, 2022
[ Upstream commit ae66fb2 ] RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see multipath-tcp/mptcp_net-next#275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
Whissi
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May 25, 2022
[ Upstream commit ba2c89e ] The MPTCP code typecasts the checksum value to u16 and then converts it to big endian while storing the value into the MPTCP option. As a result, the wire encoding for little endian host is wrong, and that causes interoperabilty interoperability issues with other implementation or host with different endianness. Address the issue writing in the packet the unmodified __sum16 value. MPTCP checksum is disabled by default, interoperating with systems with bad mptcp-level csum encoding should cause fallback to TCP. Closes: multipath-tcp/mptcp_net-next#275 Fixes: c5b39e2 ("mptcp: send out checksum for DSS") Fixes: 390b95a ("mptcp: receive checksum for DSS") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
ammarfaizi2
pushed a commit
to ammarfaizi2/linux-block
that referenced
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May 25, 2022
[ Upstream commit ba2c89e ] The MPTCP code typecasts the checksum value to u16 and then converts it to big endian while storing the value into the MPTCP option. As a result, the wire encoding for little endian host is wrong, and that causes interoperabilty interoperability issues with other implementation or host with different endianness. Address the issue writing in the packet the unmodified __sum16 value. MPTCP checksum is disabled by default, interoperating with systems with bad mptcp-level csum encoding should cause fallback to TCP. Closes: multipath-tcp/mptcp_net-next#275 Fixes: c5b39e2 ("mptcp: send out checksum for DSS") Fixes: 390b95a ("mptcp: receive checksum for DSS") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
ammarfaizi2
pushed a commit
to ammarfaizi2/linux-block
that referenced
this issue
May 25, 2022
[ Upstream commit ba2c89e ] The MPTCP code typecasts the checksum value to u16 and then converts it to big endian while storing the value into the MPTCP option. As a result, the wire encoding for little endian host is wrong, and that causes interoperabilty interoperability issues with other implementation or host with different endianness. Address the issue writing in the packet the unmodified __sum16 value. MPTCP checksum is disabled by default, interoperating with systems with bad mptcp-level csum encoding should cause fallback to TCP. Closes: multipath-tcp/mptcp_net-next#275 Fixes: c5b39e2 ("mptcp: send out checksum for DSS") Fixes: 390b95a ("mptcp: receive checksum for DSS") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
woodsts
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May 25, 2022
[ Upstream commit ba2c89e ] The MPTCP code typecasts the checksum value to u16 and then converts it to big endian while storing the value into the MPTCP option. As a result, the wire encoding for little endian host is wrong, and that causes interoperabilty interoperability issues with other implementation or host with different endianness. Address the issue writing in the packet the unmodified __sum16 value. MPTCP checksum is disabled by default, interoperating with systems with bad mptcp-level csum encoding should cause fallback to TCP. Closes: multipath-tcp/mptcp_net-next#275 Fixes: c5b39e2 ("mptcp: send out checksum for DSS") Fixes: 390b95a ("mptcp: receive checksum for DSS") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
ammarfaizi2
pushed a commit
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May 25, 2022
[ Upstream commit ba2c89e ] The MPTCP code typecasts the checksum value to u16 and then converts it to big endian while storing the value into the MPTCP option. As a result, the wire encoding for little endian host is wrong, and that causes interoperabilty interoperability issues with other implementation or host with different endianness. Address the issue writing in the packet the unmodified __sum16 value. MPTCP checksum is disabled by default, interoperating with systems with bad mptcp-level csum encoding should cause fallback to TCP. Closes: multipath-tcp/mptcp_net-next#275 Fixes: c5b39e2 ("mptcp: send out checksum for DSS") Fixes: 390b95a ("mptcp: receive checksum for DSS") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
ammarfaizi2
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May 25, 2022
commit ae66fb2 upstream. RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see multipath-tcp/mptcp_net-next#275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> [mathew.j.martineau: backport: Resolved bitfield conflict in protocol.h] Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ammarfaizi2
pushed a commit
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May 25, 2022
commit ae66fb2 upstream. RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see multipath-tcp/mptcp_net-next#275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> [mathew.j.martineau: backport: Resolved bitfield conflict in protocol.h] Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
woodsts
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May 25, 2022
commit ae66fb2 upstream. RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see multipath-tcp/mptcp_net-next#275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> [mathew.j.martineau: backport: Resolved bitfield conflict in protocol.h] Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
woodsts
pushed a commit
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May 25, 2022
commit ae66fb2 upstream. RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see multipath-tcp/mptcp_net-next#275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> [mathew.j.martineau: backport: Resolved bitfield conflict in protocol.h] Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ammarfaizi2
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May 25, 2022
commit ae66fb2 upstream. RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see multipath-tcp/mptcp_net-next#275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> [mathew.j.martineau: backport: Resolved bitfield conflict in protocol.h] Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
nine7nine
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May 27, 2022
[ Upstream commit ba2c89e ] The MPTCP code typecasts the checksum value to u16 and then converts it to big endian while storing the value into the MPTCP option. As a result, the wire encoding for little endian host is wrong, and that causes interoperabilty interoperability issues with other implementation or host with different endianness. Address the issue writing in the packet the unmodified __sum16 value. MPTCP checksum is disabled by default, interoperating with systems with bad mptcp-level csum encoding should cause fallback to TCP. Closes: multipath-tcp/mptcp_net-next#275 Fixes: c5b39e2 ("mptcp: send out checksum for DSS") Fixes: 390b95a ("mptcp: receive checksum for DSS") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
nine7nine
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May 27, 2022
commit ae66fb2 upstream. RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see multipath-tcp/mptcp_net-next#275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> [mathew.j.martineau: backport: Resolved bitfield conflict in protocol.h] Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
psndna88
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May 27, 2022
[ Upstream commit ba2c89e ] The MPTCP code typecasts the checksum value to u16 and then converts it to big endian while storing the value into the MPTCP option. As a result, the wire encoding for little endian host is wrong, and that causes interoperabilty interoperability issues with other implementation or host with different endianness. Address the issue writing in the packet the unmodified __sum16 value. MPTCP checksum is disabled by default, interoperating with systems with bad mptcp-level csum encoding should cause fallback to TCP. Closes: multipath-tcp/mptcp_net-next#275 Fixes: c5b39e2 ("mptcp: send out checksum for DSS") Fixes: 390b95a ("mptcp: receive checksum for DSS") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
psndna88
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May 27, 2022
commit ae66fb2 upstream. RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see multipath-tcp/mptcp_net-next#275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> [mathew.j.martineau: backport: Resolved bitfield conflict in protocol.h] Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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May 31, 2022
[ Upstream commit ba2c89e0ea74a904d5231643245753d77422e7f5 ] The MPTCP code typecasts the checksum value to u16 and then converts it to big endian while storing the value into the MPTCP option. As a result, the wire encoding for little endian host is wrong, and that causes interoperabilty interoperability issues with other implementation or host with different endianness. Address the issue writing in the packet the unmodified __sum16 value. MPTCP checksum is disabled by default, interoperating with systems with bad mptcp-level csum encoding should cause fallback to TCP. Closes: multipath-tcp/mptcp_net-next#275 Fixes: c5b39e2 ("mptcp: send out checksum for DSS") Fixes: 390b95a ("mptcp: receive checksum for DSS") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit ae66fb2ba6c3dcaf8b9612b65aa949a1a4bed150 upstream. RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see multipath-tcp/mptcp_net-next#275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> [mathew.j.martineau: backport: Resolved bitfield conflict in protocol.h] Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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BugLink: https://bugs.launchpad.net/bugs/1981375 [ Upstream commit ba2c89e ] The MPTCP code typecasts the checksum value to u16 and then converts it to big endian while storing the value into the MPTCP option. As a result, the wire encoding for little endian host is wrong, and that causes interoperabilty interoperability issues with other implementation or host with different endianness. Address the issue writing in the packet the unmodified __sum16 value. MPTCP checksum is disabled by default, interoperating with systems with bad mptcp-level csum encoding should cause fallback to TCP. Closes: multipath-tcp/mptcp_net-next#275 Fixes: c5b39e2 ("mptcp: send out checksum for DSS") Fixes: 390b95a ("mptcp: receive checksum for DSS") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Kamal Mostafa <kamal@canonical.com> Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
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BugLink: https://bugs.launchpad.net/bugs/1981468 commit ae66fb2 upstream. RFC 8684 section 3.7 describes several opportunities for a MPTCP connection to "fall back" to regular TCP early in the connection process, before it has been confirmed that MPTCP options can be successfully propagated on all SYN, SYN/ACK, and data packets. If a peer acknowledges the first received data packet with a regular TCP header (no MPTCP options), fallback is allowed. If the recipient of that first data packet finds a MPTCP DSS checksum error, this provides an opportunity to fail gracefully with a TCP fallback rather than resetting the connection (as might happen if a checksum failure were detected later). This commit modifies the checksum failure code to attempt fallback on the initial subflow of a MPTCP connection, only if it's a failure in the first data mapping. In cases where the peer initiates the connection, requests checksums, is the first to send data, and the peer is sending incorrect checksums (see multipath-tcp/mptcp_net-next#275), this allows the connection to proceed as TCP rather than reset. Fixes: dd8bcd1 ("mptcp: validate the data checksum") Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> [mathew.j.martineau: backport: Resolved bitfield conflict in protocol.h] Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Kamal Mostafa <kamal@canonical.com> Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
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the current encoding of the csum field in the MPTCP DSS option is wrong: the __sum value is converted to BE, inverting the byte order on LE arches, which is not expected.
@darkwrat confirmed the above causes interoperability issues between hosts with different endianess.
The solution is problematic WRT backward compatibility, but we don't have many options
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