diff mbox series

[ovs-dev,v7,1/2] Userspace: Software fallback for UDP encapsulated TCP segmentation.

Message ID 20240909050409.237360-1-mkp@redhat.com
State Accepted, archived
Commit 82c1028e371e0195a4070ee0218d9d6edb9fdc7f
Delegated to: Eelco Chaudron
Headers show
Series [ovs-dev,v7,1/2] Userspace: Software fallback for UDP encapsulated TCP segmentation. | expand

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Commit Message

Mike Pattrick Sept. 9, 2024, 5:04 a.m. UTC 
When sending packets that are flagged as requiring segmentation to an
interface that does not support this feature, send the packet to the TSO
software fallback instead of dropping it.

Reviewed-by: David Marchand <david.marchand@redhat.com>
Signed-off-by: Mike Pattrick <mkp@redhat.com>
---
v2:
 - Fixed udp tunnel length
 - Added test that UDP headers are correct
 - Split inner and outer ip_id into different counters
 - Set tunnel flags in reset_tcp_seg

v3:
 - Changed logic of netdev_send() to account for NICs that support
 tunnel offload but not checksum offload
 - Adjusted udp tunnel header length during software tso

v4:
 - Moved a bugfix into its own patch
 - Fixed an indentation issue
 - Changed the scope of ip_hdr

v5:
 - Change order of tso fallback check
 - Added a unit test
v6:
 - Removed segsize adjustment patch, adjusted tests to accomidate.
v7:
 - Applied provided diff for stylistic changes and left over test code
---
 lib/dp-packet-gso.c     |  90 +++++++++++++++-----
 lib/dp-packet.h         |  34 ++++++++
 lib/netdev.c            |  44 +++++-----
 tests/dpif-netdev.at    | 178 ++++++++++++++++++++++++++++++++++++++++
 tests/system-traffic.at |  92 +++++++++++++++++++++
 5 files changed, 397 insertions(+), 41 deletions(-)

Comments

Eelco Chaudron Sept. 10, 2024, 7:14 a.m. UTC | #1 
On 9 Sep 2024, at 7:04, Mike Pattrick wrote:

> When sending packets that are flagged as requiring segmentation to an
> interface that does not support this feature, send the packet to the TSO
> software fallback instead of dropping it.
>
> Reviewed-by: David Marchand <david.marchand@redhat.com>
> Signed-off-by: Mike Pattrick <mkp@redhat.com>

Thanks for making the additional style changes.

Acked-by: Eelco Chaudron <echaudro@redhat.com>
Eelco Chaudron Sept. 11, 2024, 3:06 p.m. UTC | #2 
On 9 Sep 2024, at 7:04, Mike Pattrick wrote:

> When sending packets that are flagged as requiring segmentation to an
> interface that does not support this feature, send the packet to the TSO
> software fallback instead of dropping it.
>
> Reviewed-by: David Marchand <david.marchand@redhat.com>
> Signed-off-by: Mike Pattrick <mkp@redhat.com>

Thanks Mike and all the reviewers. It’s applied to main.

//Eelco
diff mbox series

Patch

diff --git a/lib/dp-packet-gso.c b/lib/dp-packet-gso.c
index 847685ad9..04ebb19da 100644
--- a/lib/dp-packet-gso.c
+++ b/lib/dp-packet-gso.c
@@ -47,6 +47,8 @@  dp_packet_gso_seg_new(const struct dp_packet *p, size_t hdr_len,
     seg->l2_5_ofs = p->l2_5_ofs;
     seg->l3_ofs = p->l3_ofs;
     seg->l4_ofs = p->l4_ofs;
+    seg->inner_l3_ofs = p->inner_l3_ofs;
+    seg->inner_l4_ofs = p->inner_l4_ofs;
 
     /* The protocol headers remain the same, so preserve hash and mark. */
     *dp_packet_rss_ptr(seg) = *dp_packet_rss_ptr(p);
@@ -71,7 +73,12 @@  dp_packet_gso_nr_segs(struct dp_packet *p)
     const char *data_tail;
     const char *data_pos;
 
-    data_pos = dp_packet_get_tcp_payload(p);
+    if (dp_packet_hwol_is_tunnel_vxlan(p) ||
+        dp_packet_hwol_is_tunnel_geneve(p)) {
+        data_pos = dp_packet_get_inner_tcp_payload(p);
+    } else {
+        data_pos = dp_packet_get_tcp_payload(p);
+    }
     data_tail = (char *) dp_packet_tail(p) - dp_packet_l2_pad_size(p);
 
     return DIV_ROUND_UP(data_tail - data_pos, segsz);
@@ -89,14 +96,16 @@  dp_packet_gso(struct dp_packet *p, struct dp_packet_batch **batches)
     static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
     struct dp_packet_batch *curr_batch = *batches;
     struct tcp_header *tcp_hdr;
-    struct ip_header *ip_hdr;
+    uint16_t inner_ip_id = 0;
+    uint16_t outer_ip_id = 0;
     struct dp_packet *seg;
     uint16_t tcp_offset;
     uint16_t tso_segsz;
     uint32_t tcp_seq;
-    uint16_t ip_id;
+    bool outer_ipv4;
     int hdr_len;
     int seg_len;
+    bool tnl;
 
     tso_segsz = dp_packet_get_tso_segsz(p);
     if (!tso_segsz) {
@@ -105,20 +114,37 @@  dp_packet_gso(struct dp_packet *p, struct dp_packet_batch **batches)
         return false;
     }
 
-    tcp_hdr = dp_packet_l4(p);
+    if (dp_packet_hwol_is_tunnel_vxlan(p) ||
+        dp_packet_hwol_is_tunnel_geneve(p)) {
+        outer_ipv4 = dp_packet_hwol_is_outer_ipv4(p);
+        tcp_hdr = dp_packet_inner_l4(p);
+        tnl = true;
+
+        if (outer_ipv4) {
+            outer_ip_id = ntohs(((struct ip_header *) dp_packet_l3(p))->ip_id);
+        }
+        if (dp_packet_hwol_is_ipv4(p)) {
+            struct ip_header *ip_hdr = dp_packet_inner_l3(p);
+            inner_ip_id = ntohs(ip_hdr->ip_id);
+        }
+    } else {
+        outer_ipv4 = dp_packet_hwol_is_ipv4(p);
+        tcp_hdr = dp_packet_l4(p);
+        tnl = false;
+
+        if (outer_ipv4) {
+            struct ip_header *ip_hdr = dp_packet_l3(p);
+            outer_ip_id = ntohs(ip_hdr->ip_id);
+        }
+    }
+
     tcp_offset = TCP_OFFSET(tcp_hdr->tcp_ctl);
     tcp_seq = ntohl(get_16aligned_be32(&tcp_hdr->tcp_seq));
-    hdr_len = ((char *) dp_packet_l4(p) - (char *) dp_packet_eth(p))
+    hdr_len = ((char *) tcp_hdr - (char *) dp_packet_eth(p))
               + tcp_offset * 4;
-    ip_id = 0;
-    if (dp_packet_hwol_is_ipv4(p)) {
-        ip_hdr = dp_packet_l3(p);
-        ip_id = ntohs(ip_hdr->ip_id);
-    }
-
     const char *data_tail = (char *) dp_packet_tail(p)
                             - dp_packet_l2_pad_size(p);
-    const char *data_pos = dp_packet_get_tcp_payload(p);
+    const char *data_pos = (char *) tcp_hdr + tcp_offset * 4;
     int n_segs = dp_packet_gso_nr_segs(p);
 
     for (int i = 0; i < n_segs; i++) {
@@ -130,14 +156,36 @@  dp_packet_gso(struct dp_packet *p, struct dp_packet_batch **batches)
         seg = dp_packet_gso_seg_new(p, hdr_len, data_pos, seg_len);
         data_pos += seg_len;
 
+        if (tnl) {
+            /* Update tunnel UDP header length. */
+            struct udp_header *tnl_hdr;
+
+            tnl_hdr = dp_packet_l4(seg);
+            tnl_hdr->udp_len = htons(dp_packet_l4_size(seg));
+
+            /* Update tunnel inner L3 header. */
+            if (dp_packet_hwol_is_ipv4(seg)) {
+                struct ip_header *ip_hdr = dp_packet_inner_l3(seg);
+                ip_hdr->ip_tot_len = htons(dp_packet_inner_l3_size(seg));
+                ip_hdr->ip_id = htons(inner_ip_id);
+                ip_hdr->ip_csum = 0;
+                inner_ip_id++;
+            } else {
+                struct ovs_16aligned_ip6_hdr *ip6_hdr;
+
+                ip6_hdr = dp_packet_inner_l3(seg);
+                ip6_hdr->ip6_ctlun.ip6_un1.ip6_un1_plen
+                    = htons(dp_packet_inner_l3_size(seg) - sizeof *ip6_hdr);
+            }
+        }
+
         /* Update L3 header. */
-        if (dp_packet_hwol_is_ipv4(seg)) {
-            ip_hdr = dp_packet_l3(seg);
-            ip_hdr->ip_tot_len = htons(sizeof *ip_hdr +
-                                       dp_packet_l4_size(seg));
-            ip_hdr->ip_id = htons(ip_id);
+        if (outer_ipv4) {
+            struct ip_header *ip_hdr = dp_packet_l3(seg);
+            ip_hdr->ip_tot_len = htons(dp_packet_l3_size(seg));
+            ip_hdr->ip_id = htons(outer_ip_id);
             ip_hdr->ip_csum = 0;
-            ip_id++;
+            outer_ip_id++;
         } else {
             struct ovs_16aligned_ip6_hdr *ip6_hdr = dp_packet_l3(seg);
 
@@ -146,7 +194,11 @@  dp_packet_gso(struct dp_packet *p, struct dp_packet_batch **batches)
         }
 
         /* Update L4 header. */
-        tcp_hdr = dp_packet_l4(seg);
+        if (tnl) {
+            tcp_hdr = dp_packet_inner_l4(seg);
+        } else {
+            tcp_hdr = dp_packet_l4(seg);
+        }
         put_16aligned_be32(&tcp_hdr->tcp_seq, htonl(tcp_seq));
         tcp_seq += seg_len;
         if (OVS_LIKELY(i < (n_segs - 1))) {
diff --git a/lib/dp-packet.h b/lib/dp-packet.h
index a75b1c5cd..af1ff088f 100644
--- a/lib/dp-packet.h
+++ b/lib/dp-packet.h
@@ -529,6 +529,16 @@  dp_packet_inner_l3(const struct dp_packet *b)
            : NULL;
 }
 
+static inline size_t
+dp_packet_inner_l3_size(const struct dp_packet *b)
+{
+    return OVS_LIKELY(b->inner_l3_ofs != UINT16_MAX)
+           ? (const char *) dp_packet_tail(b)
+           - (const char *) dp_packet_inner_l3(b)
+           - dp_packet_l2_pad_size(b)
+           : 0;
+}
+
 static inline void *
 dp_packet_inner_l4(const struct dp_packet *b)
 {
@@ -563,6 +573,22 @@  dp_packet_get_tcp_payload(const struct dp_packet *b)
     return NULL;
 }
 
+static inline const void *
+dp_packet_get_inner_tcp_payload(const struct dp_packet *b)
+{
+    size_t l4_size = dp_packet_inner_l4_size(b);
+
+    if (OVS_LIKELY(l4_size >= TCP_HEADER_LEN)) {
+        struct tcp_header *tcp = dp_packet_inner_l4(b);
+        int tcp_len = TCP_OFFSET(tcp->tcp_ctl) * 4;
+
+        if (OVS_LIKELY(tcp_len >= TCP_HEADER_LEN && tcp_len <= l4_size)) {
+            return (const char *) tcp + tcp_len;
+        }
+    }
+    return NULL;
+}
+
 static inline uint32_t
 dp_packet_get_tcp_payload_length(const struct dp_packet *pkt)
 {
@@ -1320,6 +1346,14 @@  dp_packet_hwol_reset_tcp_seg(struct dp_packet *p)
         ol_flags |= DP_PACKET_OL_TX_IP_CKSUM;
     }
 
+    if (ol_flags & (DP_PACKET_OL_TX_TUNNEL_VXLAN |
+                    DP_PACKET_OL_TX_TUNNEL_GENEVE)) {
+        if (ol_flags & DP_PACKET_OL_TX_OUTER_IPV4) {
+            ol_flags |= DP_PACKET_OL_TX_OUTER_IP_CKSUM;
+        }
+        ol_flags |= DP_PACKET_OL_TX_OUTER_UDP_CKSUM;
+    }
+
     *dp_packet_ol_flags_ptr(p) = ol_flags;
 }
 
diff --git a/lib/netdev.c b/lib/netdev.c
index f2d921ed6..02beac9d0 100644
--- a/lib/netdev.c
+++ b/lib/netdev.c
@@ -69,8 +69,6 @@  COVERAGE_DEFINE(netdev_received);
 COVERAGE_DEFINE(netdev_sent);
 COVERAGE_DEFINE(netdev_add_router);
 COVERAGE_DEFINE(netdev_get_stats);
-COVERAGE_DEFINE(netdev_vxlan_tso_drops);
-COVERAGE_DEFINE(netdev_geneve_tso_drops);
 COVERAGE_DEFINE(netdev_push_header_drops);
 COVERAGE_DEFINE(netdev_soft_seg_good);
 COVERAGE_DEFINE(netdev_soft_seg_drops);
@@ -910,28 +908,30 @@  netdev_send(struct netdev *netdev, int qid, struct dp_packet_batch *batch,
     struct dp_packet *packet;
     int error;
 
-    if (userspace_tso_enabled() &&
-        !(netdev_flags & NETDEV_TX_OFFLOAD_TCP_TSO)) {
-        DP_PACKET_BATCH_FOR_EACH (i, packet, batch) {
-            if (dp_packet_hwol_is_tso(packet)) {
-                if (dp_packet_hwol_is_tunnel_vxlan(packet)
-                    && !(netdev_flags & NETDEV_TX_VXLAN_TNL_TSO)) {
-                        VLOG_WARN_RL(&rl, "%s: No VXLAN TSO support",
-                                     netdev_get_name(netdev));
-                        COVERAGE_INC(netdev_vxlan_tso_drops);
-                        dp_packet_delete_batch(batch, true);
-                        return false;
+    if (userspace_tso_enabled()) {
+        if (!(netdev_flags & NETDEV_TX_OFFLOAD_TCP_TSO)) {
+            DP_PACKET_BATCH_FOR_EACH (i, packet, batch) {
+                if (dp_packet_hwol_is_tso(packet)) {
+                    return netdev_send_tso(netdev, qid, batch, concurrent_txq);
                 }
-
-                if (dp_packet_hwol_is_tunnel_geneve(packet)
-                    && !(netdev_flags & NETDEV_TX_GENEVE_TNL_TSO)) {
-                        VLOG_WARN_RL(&rl, "%s: No GENEVE TSO support",
-                                     netdev_get_name(netdev));
-                        COVERAGE_INC(netdev_geneve_tso_drops);
-                        dp_packet_delete_batch(batch, true);
-                        return false;
+            }
+        } else if (!(netdev_flags & (NETDEV_TX_VXLAN_TNL_TSO |
+                                     NETDEV_TX_GENEVE_TNL_TSO))) {
+            DP_PACKET_BATCH_FOR_EACH (i, packet, batch) {
+                if (dp_packet_hwol_is_tso(packet) &&
+                    (dp_packet_hwol_is_tunnel_vxlan(packet) ||
+                     dp_packet_hwol_is_tunnel_geneve(packet))) {
+                    return netdev_send_tso(netdev, qid, batch, concurrent_txq);
+                }
+            }
+        } else if (!(netdev_flags & NETDEV_TX_OFFLOAD_OUTER_UDP_CKSUM)) {
+            DP_PACKET_BATCH_FOR_EACH (i, packet, batch) {
+                if (dp_packet_hwol_is_tso(packet) &&
+                    (dp_packet_hwol_is_tunnel_vxlan(packet) ||
+                     dp_packet_hwol_is_tunnel_geneve(packet)) &&
+                    dp_packet_hwol_is_outer_udp_cksum(packet)) {
+                    return netdev_send_tso(netdev, qid, batch, concurrent_txq);
                 }
-                return netdev_send_tso(netdev, qid, batch, concurrent_txq);
             }
         }
     }
diff --git a/tests/dpif-netdev.at b/tests/dpif-netdev.at
index bdc24cc30..5189e4893 100644
--- a/tests/dpif-netdev.at
+++ b/tests/dpif-netdev.at
@@ -884,6 +884,184 @@  AT_CHECK_UNQUOTED([ovs-pcap p2.pcap], [0], [dnl
 OVS_VSWITCHD_STOP
 AT_CLEANUP
 
+AT_SETUP([userspace offload - tunnel tso fallback])
+OVS_VSWITCHD_START([set Open_vSwitch . other_config:userspace-tso-enable=true \
+                    -- add-br br1 -- set bridge br1 datapath-type=dummy \
+                       other-config:hwaddr=aa:55:aa:55:00:03 \
+                    -- add-port br1 p1 -- set Interface p1 type=dummy \
+                       ofport_request=1])
+AT_CHECK([ovs-vsctl add-br int-br -- set bridge int-br datapath_type=dummy \
+                    -- add-port int-br t1 -- set Interface t1 type=vxlan \
+                       options:remote_ip=1.1.2.92 options:key=123 \
+                       options:csum=true ofport_request=2 \
+                    -- add-port int-br t2 -- set Interface t2 type=geneve \
+                       options:remote_ip=1.1.2.92 options:key=123 \
+                       options:csum=true ofport_request=3 \
+                    -- add-port int-br t3 -- set Interface t3 type=vxlan \
+                       options:remote_ip=2001:cafe::93 options:key=123 \
+                       options:csum=true ofport_request=4 \
+                    -- add-port int-br t4 -- set Interface t4 type=geneve \
+                       options:remote_ip=2001:cafe::93 options:key=123 \
+                       options:csum=true ofport_request=5], [0])
+
+flow_s="eth(src=8a:bf:7e:2f:05:84,dst=0a:8f:39:4f:e0:73),eth_type(0x0800),
+        ipv4(src=192.168.123.2,dst=192.168.123.1,proto=6,tos=1,ttl=64,frag=no),
+        tcp(src=54392,dst=5201),tcp_flags(ack)"
+
+flow_s_v6="eth(src=8a:bf:7e:2f:05:84,dst=0a:8f:39:4f:e0:73),eth_type(0x86dd),
+           ipv6(src=2001:cafe::88,dst=2001:cafe::92,proto=6),
+           tcp(src=54392,dst=5201),tcp_flags(ack)"
+
+dnl Setup dummy interface tunnel connectivity.
+AT_CHECK([ovs-appctl netdev-dummy/ip4addr br1 1.1.2.88/24], [0], [OK
+])
+AT_CHECK([ovs-appctl netdev-dummy/ip6addr br1 2001:cafe::88/24], [0], [OK
+])
+AT_CHECK([ovs-appctl tnl/neigh/set br1 1.1.2.92 aa:bb:cc:00:00:01], [0], [OK
+])
+AT_CHECK([ovs-appctl tnl/neigh/set br1 2001:cafe::93 aa:bb:cc:00:00:06], [0],
+         [OK
+])
+AT_CHECK([ovs-appctl tnl/egress_port_range 57363 57363], [0], [OK
+])
+AT_CHECK([ovs-ofctl add-flow br1 action=normal])
+AT_CHECK([ovs-ofctl add-flow int-br action=normal])
+
+dnl Configure the TX interface to segment.
+AT_CHECK([ovs-vsctl set Interface p1 options:tx_pcap=p1.pcap -- \
+                    set Interface int-br options:ol_ip_csum=true -- \
+                    set Interface int-br options:ol_ip_csum_set_good=false -- \
+                    set Interface int-br options:ol_tso_segsz=500])
+
+AT_CHECK([ovs-appctl netdev-dummy/receive int-br "in_port(2),${flow_s}" \
+          --len 2054])
+AT_CHECK([ovs-appctl netdev-dummy/receive int-br "in_port(2),${flow_s_v6}" \
+          --len 2074])
+
+dnl Check that first we have the following packets:
+dnl - IPv4 VXLAN tunnel with IPv4 payload
+dnl - IPv4 VXLAN tunnel with IPv6 payload
+dnl - IPv6 VXLAN tunnel with IPv4 payload
+dnl - IPv6 VXLAN tunnel with IPv6 payload
+dnl - IPv4 Geneve tunnel with IPv4 payload
+dnl - IPv4 Geneve tunnel with IPv6 payload
+dnl - IPv6 Geneve tunnel with IPv4 payload
+dnl - IPv6 Geneve tunnel with IPv6 payload
+dnl - IPv6 Geneve tunnel with IPv4 payload
+dnl - IPv6 Geneve tunnel with IPv6 payload
+dnl These are sorted since OVS may send payloads to the tunnels in any order.
+zero400=$(printf '0%.0s' $(seq 800))
+zero100=$(printf '0%.0s' $(seq 200))
+AT_CHECK_UNQUOTED([ovs-pcap p1.pcap | sort], [0], [dnl
+[aabbcc000001aa55aa55000308004500026200004000401131d6010102580101025ce01312b5024e5f360800000000007b00]dnl
+[0a8f394fe0738abf7e2f058486dd60000000020806002001cafe0000000000000000000000882001cafe0000000000000000]dnl
+[00000092d4781451000000000000000050100000edfd0000${zero100}${zero400}]
+[aabbcc000001aa55aa55000308004500026200004000401131d6010102580101025ce01317c1024efcd10000655800007b00]dnl
+[0a8f394fe0738abf7e2f058486dd60000000020806002001cafe0000000000000000000000882001cafe0000000000000000]dnl
+[00000092d4781451000000000000000050100000edfd0000${zero100}${zero400}]
+[aabbcc000001aa55aa55000308004500026200014000401131d5010102580101025ce01312b5024e5f360800000000007b00]dnl
+[0a8f394fe0738abf7e2f058486dd60000000020806002001cafe0000000000000000000000882001cafe0000000000000000]dnl
+[00000092d4781451000001f40000000050100000ec090000${zero100}${zero400}]
+[aabbcc000001aa55aa55000308004500026200014000401131d5010102580101025ce01317c1024efcd10000655800007b00]dnl
+[0a8f394fe0738abf7e2f058486dd60000000020806002001cafe0000000000000000000000882001cafe0000000000000000]dnl
+[00000092d4781451000001f40000000050100000ec090000${zero100}${zero400}]
+[aabbcc000001aa55aa55000308004500026200024000401131d4010102580101025ce01312b5024e5f360800000000007b00]dnl
+[0a8f394fe0738abf7e2f058486dd60000000020806002001cafe0000000000000000000000882001cafe0000000000000000]dnl
+[00000092d4781451000003e80000000050100000ea150000${zero100}${zero400}]
+[aabbcc000001aa55aa55000308004500026200024000401131d4010102580101025ce01317c1024efcd10000655800007b00]dnl
+[0a8f394fe0738abf7e2f058486dd60000000020806002001cafe0000000000000000000000882001cafe0000000000000000]dnl
+[00000092d4781451000003e80000000050100000ea150000${zero100}${zero400}]
+[aabbcc000001aa55aa55000308004500026200034000401131d3010102580101025ce01312b5024e5f360800000000007b00]dnl
+[0a8f394fe0738abf7e2f058486dd60000000020806002001cafe0000000000000000000000882001cafe0000000000000000]dnl
+[00000092d4781451000005dc0000000050100000e8210000${zero100}${zero400}]
+[aabbcc000001aa55aa55000308004500026200034000401131d3010102580101025ce01317c1024efcd10000655800007b00]dnl
+[0a8f394fe0738abf7e2f058486dd60000000020806002001cafe0000000000000000000000882001cafe0000000000000000]dnl
+[00000092d4781451000005dc0000000050100000e8210000${zero100}${zero400}]
+[aabbcc000001aa55aa55000308004501024e00004000401131e9010102580101025ce01312b5023abd990800000000007b00]dnl
+[0a8f394fe0738abf7e2f058408004501021c0000000040060187c0a87b02c0a87b01d4781451000000000000000050100000]dnl
+[4dc20000${zero100}${zero400}]
+[aabbcc000001aa55aa55000308004501024e00004000401131e9010102580101025ce01317c1023a5b350000655800007b00]dnl
+[0a8f394fe0738abf7e2f058408004501021c0000000040060187c0a87b02c0a87b01d4781451000000000000000050100000]dnl
+[4dc20000${zero100}${zero400}]
+[aabbcc000001aa55aa55000308004501024e00014000401131e8010102580101025ce01312b5023abd990800000000007b00]dnl
+[0a8f394fe0738abf7e2f058408004501021c0001000040060186c0a87b02c0a87b01d4781451000001f40000000050100000]dnl
+[4bce0000${zero100}${zero400}]
+[aabbcc000001aa55aa55000308004501024e00014000401131e8010102580101025ce01317c1023a5b350000655800007b00]dnl
+[0a8f394fe0738abf7e2f058408004501021c0001000040060186c0a87b02c0a87b01d4781451000001f40000000050100000]dnl
+[4bce0000${zero100}${zero400}]
+[aabbcc000001aa55aa55000308004501024e00024000401131e7010102580101025ce01312b5023abd990800000000007b00]dnl
+[0a8f394fe0738abf7e2f058408004501021c0002000040060185c0a87b02c0a87b01d4781451000003e80000000050100000]dnl
+[49da0000${zero100}${zero400}]
+[aabbcc000001aa55aa55000308004501024e00024000401131e7010102580101025ce01317c1023a5b350000655800007b00]dnl
+[0a8f394fe0738abf7e2f058408004501021c0002000040060185c0a87b02c0a87b01d4781451000003e80000000050100000]dnl
+[49da0000${zero100}${zero400}]
+[aabbcc000001aa55aa55000308004501024e00034000401131e6010102580101025ce01312b5023abd990800000000007b00]dnl
+[0a8f394fe0738abf7e2f058408004501021c0003000040060184c0a87b02c0a87b01d4781451000005dc0000000050100000]dnl
+[47e60000${zero100}${zero400}]
+[aabbcc000001aa55aa55000308004501024e00034000401131e6010102580101025ce01317c1023a5b350000655800007b00]dnl
+[0a8f394fe0738abf7e2f058408004501021c0003000040060184c0a87b02c0a87b01d4781451000005dc0000000050100000]dnl
+[47e60000${zero100}${zero400}]
+[aabbcc000006aa55aa55000386dd60000000024e11402001cafe0000000000000000000000882001cafe0000000000000000]dnl
+[00000093e01312b5024e8ed10800000000007b000a8f394fe0738abf7e2f058486dd60000000020806002001cafe00000000]dnl
+[00000000000000882001cafe000000000000000000000092d4781451000000000000000050100000edfd0000${zero100}]dnl
+[${zero400}]
+[aabbcc000006aa55aa55000386dd60000000024e11402001cafe0000000000000000000000882001cafe0000000000000000]dnl
+[00000093e01312b5024e8ed10800000000007b000a8f394fe0738abf7e2f058486dd60000000020806002001cafe00000000]dnl
+[00000000000000882001cafe000000000000000000000092d4781451000001f40000000050100000ec090000${zero100}]dnl
+[${zero400}]
+[aabbcc000006aa55aa55000386dd60000000024e11402001cafe0000000000000000000000882001cafe0000000000000000]dnl
+[00000093e01312b5024e8ed10800000000007b000a8f394fe0738abf7e2f058486dd60000000020806002001cafe00000000]dnl
+[00000000000000882001cafe000000000000000000000092d4781451000003e80000000050100000ea150000${zero100}]dnl
+[${zero400}]
+[aabbcc000006aa55aa55000386dd60000000024e11402001cafe0000000000000000000000882001cafe0000000000000000]dnl
+[00000093e01312b5024e8ed10800000000007b000a8f394fe0738abf7e2f058486dd60000000020806002001cafe00000000]dnl
+[00000000000000882001cafe000000000000000000000092d4781451000005dc0000000050100000e8210000${zero100}]dnl
+[${zero400}]
+[aabbcc000006aa55aa55000386dd60000000024e11402001cafe0000000000000000000000882001cafe0000000000000000]dnl
+[00000093e01317c1024e2c6d0000655800007b000a8f394fe0738abf7e2f058486dd60000000020806002001cafe00000000]dnl
+[00000000000000882001cafe000000000000000000000092d4781451000000000000000050100000edfd0000${zero100}]dnl
+[${zero400}]
+[aabbcc000006aa55aa55000386dd60000000024e11402001cafe0000000000000000000000882001cafe0000000000000000]dnl
+[00000093e01317c1024e2c6d0000655800007b000a8f394fe0738abf7e2f058486dd60000000020806002001cafe00000000]dnl
+[00000000000000882001cafe000000000000000000000092d4781451000001f40000000050100000ec090000${zero100}]dnl
+[${zero400}]
+[aabbcc000006aa55aa55000386dd60000000024e11402001cafe0000000000000000000000882001cafe0000000000000000]dnl
+[00000093e01317c1024e2c6d0000655800007b000a8f394fe0738abf7e2f058486dd60000000020806002001cafe00000000]dnl
+[00000000000000882001cafe000000000000000000000092d4781451000003e80000000050100000ea150000${zero100}]dnl
+[${zero400}]
+[aabbcc000006aa55aa55000386dd60000000024e11402001cafe0000000000000000000000882001cafe0000000000000000]dnl
+[00000093e01317c1024e2c6d0000655800007b000a8f394fe0738abf7e2f058486dd60000000020806002001cafe00000000]dnl
+[00000000000000882001cafe000000000000000000000092d4781451000005dc0000000050100000e8210000${zero100}]dnl
+[${zero400}]
+[aabbcc000006aa55aa55000386dd60100000023a11402001cafe0000000000000000000000882001cafe0000000000000000]dnl
+[00000093e01312b5023aed340800000000007b000a8f394fe0738abf7e2f058408004501021c0000000040060187c0a87b02]dnl
+[c0a87b01d47814510000000000000000501000004dc20000${zero100}${zero400}]
+[aabbcc000006aa55aa55000386dd60100000023a11402001cafe0000000000000000000000882001cafe0000000000000000]dnl
+[00000093e01312b5023aed340800000000007b000a8f394fe0738abf7e2f058408004501021c0001000040060186c0a87b02]dnl
+[c0a87b01d4781451000001f400000000501000004bce0000${zero100}${zero400}]
+[aabbcc000006aa55aa55000386dd60100000023a11402001cafe0000000000000000000000882001cafe0000000000000000]dnl
+[00000093e01312b5023aed340800000000007b000a8f394fe0738abf7e2f058408004501021c0002000040060185c0a87b02]dnl
+[c0a87b01d4781451000003e8000000005010000049da0000${zero100}${zero400}]
+[aabbcc000006aa55aa55000386dd60100000023a11402001cafe0000000000000000000000882001cafe0000000000000000]dnl
+[00000093e01312b5023aed340800000000007b000a8f394fe0738abf7e2f058408004501021c0003000040060184c0a87b02]dnl
+[c0a87b01d4781451000005dc000000005010000047e60000${zero100}${zero400}]
+[aabbcc000006aa55aa55000386dd60100000023a11402001cafe0000000000000000000000882001cafe0000000000000000]dnl
+[00000093e01317c1023a8ad00000655800007b000a8f394fe0738abf7e2f058408004501021c0000000040060187c0a87b02]dnl
+[c0a87b01d47814510000000000000000501000004dc20000${zero100}${zero400}]
+[aabbcc000006aa55aa55000386dd60100000023a11402001cafe0000000000000000000000882001cafe0000000000000000]dnl
+[00000093e01317c1023a8ad00000655800007b000a8f394fe0738abf7e2f058408004501021c0001000040060186c0a87b02]dnl
+[c0a87b01d4781451000001f400000000501000004bce0000${zero100}${zero400}]
+[aabbcc000006aa55aa55000386dd60100000023a11402001cafe0000000000000000000000882001cafe0000000000000000]dnl
+[00000093e01317c1023a8ad00000655800007b000a8f394fe0738abf7e2f058408004501021c0002000040060185c0a87b02]dnl
+[c0a87b01d4781451000003e8000000005010000049da0000${zero100}${zero400}]
+[aabbcc000006aa55aa55000386dd60100000023a11402001cafe0000000000000000000000882001cafe0000000000000000]dnl
+[00000093e01317c1023a8ad00000655800007b000a8f394fe0738abf7e2f058408004501021c0003000040060184c0a87b02]dnl
+[c0a87b01d4781451000005dc000000005010000047e60000${zero100}${zero400}]
+])
+
+OVS_VSWITCHD_STOP
+AT_CLEANUP
+
 AT_SETUP([dpif-netdev - revalidators handle dp modification fail correctly])
 OVS_VSWITCHD_START(
   [add-port br0 p1 \
diff --git a/tests/system-traffic.at b/tests/system-traffic.at
index 202ff0492..724b25fa9 100644
--- a/tests/system-traffic.at
+++ b/tests/system-traffic.at
@@ -351,6 +351,98 @@  OVS_WAIT_UNTIL([diff -q payload.bin udp_data])
 OVS_TRAFFIC_VSWITCHD_STOP
 AT_CLEANUP
 
+AT_SETUP([datapath - tcp over vxlan tunnel with software fallback])
+AT_SKIP_IF([test $HAVE_NC = no])
+AT_SKIP_IF([test $HAVE_TCPDUMP = no])
+OVS_CHECK_VXLAN()
+
+dnl This test is only valid with tso. If the kernel segments the packets, the
+dnl packet lengths in the final test will be different.
+m4_ifndef([CHECK_SYSTEM_TSO], [AT_SKIP_IF(:)])
+
+OVS_TRAFFIC_VSWITCHD_START()
+ADD_BR([br-underlay])
+
+AT_CHECK([ovs-ofctl add-flow br0 "actions=normal"])
+AT_CHECK([ovs-ofctl add-flow br-underlay "actions=normal"])
+
+ADD_NAMESPACES(at_ns0)
+
+dnl Set up underlay link from host into the namespace using veth pair.
+ADD_VETH(p0, at_ns0, br-underlay, "172.31.1.1/24")
+AT_CHECK([ip addr add dev br-underlay "172.31.1.100/24"])
+AT_CHECK([ip link set dev br-underlay up])
+
+dnl Test the case where one side has all checksum and TSO offload disabled.
+AT_CHECK([ethtool -K ovs-p0 tso off], [0], [ignore], [ignore])
+AT_CHECK([ethtool -K ovs-p0 sg off], [0], [ignore], [ignore])
+
+dnl Reinitialize.
+AT_CHECK([ovs-vsctl del-port ovs-p0])
+AT_CHECK([ovs-vsctl add-port br-underlay ovs-p0])
+
+dnl Set up tunnel endpoints on OVS outside the namespace and with a native
+dnl linux device inside the namespace.
+ADD_OVS_TUNNEL([vxlan], [br0], [at_vxlan0], [172.31.1.1], [10.1.1.100/24])
+ADD_NATIVE_TUNNEL([vxlan], [at_vxlan1], [at_ns0], [172.31.1.100],
+                  [10.1.1.1/24], [id 0 dstport 4789])
+
+dnl Set MTU for tunnel to generate 1500 byte packets.
+AT_CHECK([ip link set dev br0 mtu 1400])
+
+dnl First, check the underlay.
+NS_CHECK_EXEC([at_ns0], [ping -q -c 3 -i 0.3 -W 2 172.31.1.100 | FORMAT_PING],
+              [0], [dnl
+3 packets transmitted, 3 received, 0% packet loss, time 0ms
+])
+
+dnl Check that the tunnel is up.
+NS_CHECK_EXEC([at_ns0], [ping -q -c 3 -i 0.3 -W 2 10.1.1.100 | FORMAT_PING],
+              [0], [dnl
+3 packets transmitted, 3 received, 0% packet loss, time 0ms
+])
+
+dnl Start tcpdump to capture the encapsulated packets.
+OVS_DAEMONIZE([tcpdump -i ovs-p0 -w p0.pcap], [tcpdump.pid])
+
+dnl Wait until the pcap is written, which happens after the interface
+dnl is opened by tcpdump.
+OVS_WAIT_UNTIL([test -e p0.pcap])
+
+dnl Initialize the listener before it is needed.
+NETNS_DAEMONIZE([at_ns0], [nc -l 10.1.1.1 1234 > data2], [nc.pid])
+
+dnl Verify that ncat is ready.
+OVS_WAIT_UNTIL([NS_EXEC([at_ns0], [netstat -ln | grep :1234])])
+
+dnl Large TCP transfer aimed towards ovs-p0, which has TSO disabled.
+AT_CHECK([dd if=/dev/urandom of=payload.bin bs=60000 count=1 2> /dev/null])
+AT_CHECK([nc $NC_EOF_OPT 10.1.1.1 1234 < payload.bin])
+
+dnl Wait until transfer completes before checking.
+OVS_WAIT_WHILE([kill -0 $(cat nc.pid)])
+AT_CHECK([diff -q payload.bin data2], [0])
+OVS_WAIT_WHILE([test $(stat -c %s p0.pcap) -le 68000 ])
+
+dnl Stop OVS and tcpdump and verify the results.
+AT_CHECK([kill -15 $(cat tcpdump.pid)])
+OVS_WAIT_WHILE([kill -0 $(cat tcpdump.pid)])
+
+dnl The exact number of packets sent will vary, but we check that the largest
+dnl segments have the correct lengths and certain other fields.
+AT_CHECK([test $(ovs-pcap p0.pcap | grep -Ec dnl
+"^.{24}0800"dnl Ethernet
+"450005aa....4000..11....ac1f0164ac1f0101"dnl IP(len=1450, DF, UDP, 172.31.1.100->172.31.1.1)
+"....12b505960000"dnl UDP(len=1430, dport=4789)
+"0800000000000000"dnl VXLAN(gpid=0, vni=0)
+".{24}0800"dnl Ethernet
+"45000578....4000..06....0a0101640a010101"dnl IP(len=1400, DF, TCP, 10.1.1.100->10.1.1.1)
+"....04d2............................0000"dnl TCP(dport=1234
+) -ge 20])
+
+OVS_TRAFFIC_VSWITCHD_STOP
+AT_CLEANUP
+
 AT_SETUP([datapath - ping vlan over vxlan tunnel])
 OVS_CHECK_TUNNEL_TSO()
 OVS_CHECK_VXLAN()