vRouter: Mirroring does not work if the mirror destination is local

[Anand H. Krishnan]

For packets that are tunneled, vRouter updates the checksum offset of the packet to reflect tunnel addition. For mirrored packets, if the mirror destination (analyzer) is local, no tunnel headers (MPLSO(UDP/GRE)) are added and hence a checksum offset update is not done. This behavior is wrong since we do add mirror headers (and hence a tunnel) and the whole packet needs a checksum value.

Because of this bug, sometimes we will observe that the checksum offset is not in the head skb, for which the NIC drivers may not be able to calculate checksums.

(From Raja)

When the packet is received by the virtio driver in the analyzer VM, it is seeing frame error (in "ifconfig eth0"). The VM sees these errors as a result of this check in the virtio driver:

        if (hdr->hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
                pr_debug("Needs csum!\n");
                if (!skb_partial_csum_set(skb,
                                          hdr->hdr.csum_start,
                                          hdr->hdr.csum_offset))
                        goto frame_err;

skb_partial_csum_set() is returning 0 as the csum_start and csum_offset are greater than skb_headlen.

[OpenContrail Admin (ci-admin-f)]

Review in progress for https://review.opencontrail.org/15965
Submitter: Anand H. Krishnan (<email address hidden>)

[OpenContrail Admin (ci-admin-f)]

Reviewed: https://review.opencontrail.org/15965
Committed: http://github.org/Juniper/contrail-vrouter/commit/d6703ada5dbe8638ac83d0f3801c12246852d513
Submitter: Zuul
Branch: R2.20

commit d6703ada5dbe8638ac83d0f3801c12246852d513
Author: Anand H. Krishnan <email address hidden>
Date: Tue Dec 22 12:36:08 2015 +0530

If needed, DP originated packets should undergo csum/gso updates

For packets that are tunneled, vRouter updates the checksum offset of
the packet to reflect tunnel addition. For mirrored packets, if the
mirror destination (analyzer) is local, no tunnel headers
(MPLSO(UDP/GRE)) are added and hence a checksum offset update is not
done. This behavior is wrong since we do add mirror headers (and hence a
tunnel) and the whole packet needs a checksum value.

Change-Id: Ia8c184d0980e7880bff90ff53f178e657a6be311
Closes-BUG: #1528460

[OpenContrail Admin (ci-admin-f)]

Review in progress for https://review.opencontrail.org/16205
Submitter: Anand H. Krishnan (<email address hidden>)

[OpenContrail Admin (ci-admin-f)]

Reviewed: https://review.opencontrail.org/16205
Committed: http://github.org/Juniper/contrail-vrouter/commit/9d89a04c691239ff68282a94afa9b36ee6fc45d5
Submitter: Zuul
Branch: master

commit 9d89a04c691239ff68282a94afa9b36ee6fc45d5
Author: Anand H. Krishnan <email address hidden>
Date: Tue Dec 22 12:36:08 2015 +0530

If needed, DP originated packets should undergo csum/gso updates

For packets that are tunneled, vRouter updates the checksum offset of
the packet to reflect tunnel addition. For mirrored packets, if the
mirror destination (analyzer) is local, no tunnel headers
(MPLSO(UDP/GRE)) are added and hence a checksum offset update is not
done. This behavior is wrong since we do add mirror headers (and hence a
tunnel) and the whole packet needs a checksum value.

Change-Id: Ia8c184d0980e7880bff90ff53f178e657a6be311
Closes-BUG: #1528460

[OpenContrail Admin (ci-admin-f)]

Review in progress for https://review.opencontrail.org/16679
Submitter: Vinay Vithal Mahuli (<email address hidden>)

[OpenContrail Admin (ci-admin-f)]

Reviewed: https://review.opencontrail.org/16679
Committed: http://github.org/Juniper/contrail-vrouter/commit/36e6aeae94d25173936ecb183f915cd2931dcd2d
Submitter: Zuul
Branch: R2.22.x

commit 36e6aeae94d25173936ecb183f915cd2931dcd2d
Author: Anand H. Krishnan <email address hidden>
Date: Tue Dec 22 12:36:08 2015 +0530

If needed, DP originated packets should undergo csum/gso updates

For packets that are tunneled, vRouter updates the checksum offset of
the packet to reflect tunnel addition. For mirrored packets, if the
mirror destination (analyzer) is local, no tunnel headers
(MPLSO(UDP/GRE)) are added and hence a checksum offset update is not
done. This behavior is wrong since we do add mirror headers (and hence a
tunnel) and the whole packet needs a checksum value.

Change-Id: Ia8c184d0980e7880bff90ff53f178e657a6be311
Closes-BUG: #1528460

[OpenContrail Admin (ci-admin-f)]

Review in progress for https://review.opencontrail.org/18466
Submitter: Anand H. Krishnan (<email address hidden>)

[OpenContrail Admin (ci-admin-f)]

Reviewed: https://review.opencontrail.org/18466
Committed: http://github.org/Juniper/contrail-vrouter/commit/a2b4d25deb74a94bce1ff27a0fd999419a13f630
Submitter: Zuul
Branch: R2.21.x

commit a2b4d25deb74a94bce1ff27a0fd999419a13f630
Author: Anand H. Krishnan <email address hidden>
Date: Tue Dec 22 12:36:08 2015 +0530

If needed, DP originated packets should undergo csum/gso updates

For packets that are tunneled, vRouter updates the checksum offset of
the packet to reflect tunnel addition. For mirrored packets, if the
mirror destination (analyzer) is local, no tunnel headers
(MPLSO(UDP/GRE)) are added and hence a checksum offset update is not
done. This behavior is wrong since we do add mirror headers (and hence a
tunnel) and the whole packet needs a checksum value.

Change-Id: Ia8c184d0980e7880bff90ff53f178e657a6be311
Closes-BUG: #1528460