[ovs-dev,v8,5/9] Userspace datapath: Add fragmentation handling.

Message ID 1531795191-58140-6-git-send-email-dlu998@gmail.com
State Changes Requested
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Series
  • Userspace datapath: Add fragmentation support.
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Commit Message

Darrell Ball July 17, 2018, 2:39 a.m.
Fragmentation handling is added for supporting conntrack.
Both v4 and v6 are supported.

After discussion with several people, I decided to not store
configuration state in the database to be more consistent with
the kernel in future, similarity with other conntrack configuration
which will not be in the database as well and overall simplicity.
Accordingly, fragmentation handling is enabled by default.

This patch enables fragmentation tests for the userspace datapath.

Signed-off-by: Darrell Ball <dlu998@gmail.com>
---
 NEWS                             |    2 +
 include/sparse/netinet/ip6.h     |    1 +
 lib/automake.mk                  |    2 +
 lib/conntrack.c                  |   13 +-
 lib/ipf.c                        | 1299 ++++++++++++++++++++++++++++++++++++++
 lib/ipf.h                        |   60 ++
 tests/system-kmod-macros.at      |   10 +-
 tests/system-traffic.at          |   30 +-
 tests/system-userspace-macros.at |   26 +-
 9 files changed, 1398 insertions(+), 45 deletions(-)
 create mode 100644 lib/ipf.c
 create mode 100644 lib/ipf.h

Comments

Justin Pettit Aug. 1, 2018, 9:36 a.m. | #1
> On Jul 16, 2018, at 7:39 PM, Darrell Ball <dlu998@gmail.com> wrote:
> 
> +static void
> +ipf_expiry_list_add(struct ipf_list *ipf_list, long long now)
> +    OVS_REQUIRES(ipf_lock)
> +{
> +    enum {
> +        IPF_FRAG_LIST_TIMEOUT_DEFAULT = 15000,
> +    };
> +
> +    ipf_list->expiration = now + IPF_FRAG_LIST_TIMEOUT_DEFAULT;
> +    ovs_list_push_back(&frag_exp_list, &ipf_list->list_node);
> +}

This was brought up in the previous review, and I think we should drop "_DEFAULT", since it's not configurable.

> +static bool
> +ipf_return_invalid(struct dp_packet *pkt)
> +{
> +    pkt->md.ct_state = CS_INVALID;
> +    return false;
> +}

This function looks kind of odd to me.  I think the same thing could be accomplished more clearly with a goto in the functions that need it.  I've implemented it in my incremental, below.

> +
> +static bool
> +ipf_is_valid_v4_frag(struct dp_packet *pkt)
> +{
> +    if (OVS_UNLIKELY(dp_packet_ip_checksum_bad(pkt))) {
> +        return ipf_return_invalid(pkt);
> +    }

Do you think it would make sense to provide a counter when a packet gets marked as invalid?

> +static void
> +ipf_extract_frags_from_batch(struct dp_packet_batch *pb, ovs_be16 dl_type,
> +                             uint16_t zone, long long now, uint32_t hash_basis)
> +{
> +    const size_t pb_cnt = dp_packet_batch_size(pb);
> +    int pb_idx; /* Index in a packet batch. */
> +    struct dp_packet *pkt;
> +
> +    DP_PACKET_BATCH_REFILL_FOR_EACH (pb_idx, pb_cnt, pkt, pb) {
> +
> +        if (OVS_UNLIKELY((dl_type == htons(ETH_TYPE_IP) &&
> +                          ipf_is_valid_v4_frag(pkt)) ||
> +                         (dl_type == htons(ETH_TYPE_IPV6) &&
> +                          ipf_is_valid_v6_frag(pkt)))) {

Is this case unlikely?

> diff --git a/lib/ipf.h b/lib/ipf.h
> new file mode 100644
> index 0000000..212d1b3
> --- /dev/null
> +++ b/lib/ipf.h
> ...
> +struct ipf_status {
> +   bool ifp_v4_enabled;
> +   unsigned int min_v4_frag_size;
> +   unsigned int nfrag_max;
> +   unsigned int nfrag;
> +   unsigned int n4frag_accepted;
> +   unsigned int n4frag_completed_sent;
> +   unsigned int n4frag_expired_sent;
> +   unsigned int n4frag_too_small;
> +   unsigned int n4frag_overlap;
> +   bool ifp_v6_enabled;
> +   unsigned int min_v6_frag_size;
> +   unsigned int n6frag_accepted;
> +   unsigned int n6frag_completed_sent;
> +   unsigned int n6frag_expired_sent;
> +   unsigned int n6frag_too_small;
> +   unsigned int n6frag_overlap;
> +};

This isn't used until a later patch.  Let's wait to introduce it until then.

> +/* Collects and reassembles fragments which are to be sent through
> + * conntrack, if fragment processing is enabled or fragments are
> + * in flight. */
> +void ipf_preprocess_conntrack(struct dp_packet_batch *pb, long long now,
> +                              ovs_be16 dl_type, uint16_t zone,
> +                              uint32_t hash_basis);
> +
> +/* Updates the state of fragments associated with reassembled packets and
> + * sends out fragments that are either associated with completed
> + * packets or expired, if fragment processing is enabled or fragments are
> + * in flight. */
> +void ipf_postprocess_conntrack(struct dp_packet_batch *pb, long long now,
> +                               ovs_be16 dl_type);

These functions are also described in "ipf.c".  Let's just use the ones there so that we don't have to worry about them drifting apart.

I'd like to commit it with the incremental at the bottom of this message.

--Justin


-=-=-=-=-=-=-=-=-=-=-

diff --git a/lib/ipf.c b/lib/ipf.c
index 1169a8a5e60c..bb2e2d692036 100644
--- a/lib/ipf.c
+++ b/lib/ipf.c
@@ -106,12 +106,12 @@ struct ipf_list {
     struct ovs_list list_node;
     struct ipf_frag *frag_list;
     struct ipf_list_key key;
-    struct dp_packet *reass_execute_ctx; /* reassembled packet. */
-    long long expiration;
-    int last_sent_idx;               /* last sent fragment idx. */
-    int last_inuse_idx;             /* last inuse fragment idx. */
-    int size;                            /* fragment list size. */
-    uint8_t state;      /* frag list state; see ipf_list_state. */
+    struct dp_packet *reass_execute_ctx; /* Reassembled packet. */
+    long long expiration;          /* In milliseconds. */
+    int last_sent_idx;             /* Last sent fragment idx. */
+    int last_inuse_idx;            /* Last inuse fragment idx. */
+    int size;                      /* Fragment list size. */
+    uint8_t state;                 /* Frag list state; see ipf_list_state. */
 };
 
 struct reassembled_pkt {
@@ -266,10 +266,10 @@ ipf_expiry_list_add(struct ipf_list *ipf_list, long long now)
     OVS_REQUIRES(ipf_lock)
 {
     enum {
-        IPF_FRAG_LIST_TIMEOUT_DEFAULT = 15000,
+        IPF_FRAG_LIST_TIMEOUT = 15000,
     };
 
-    ipf_list->expiration = now + IPF_FRAG_LIST_TIMEOUT_DEFAULT;
+    ipf_list->expiration = now + IPF_FRAG_LIST_TIMEOUT;
     ovs_list_push_back(&frag_exp_list, &ipf_list->list_node);
 }
 
@@ -447,7 +447,7 @@ ipf_reassemble_v4_frags(struct ipf_list *ipf_list)
         len += add_len;
         if (len > IPV4_PACKET_MAX_SIZE) {
             ipf_print_reass_packet(
-                "Unsupported big reassmbled v4 packet; v4 hdr:", l3);
+                "Unsupported big reassembled v4 packet; v4 hdr:", l3);
             dp_packet_delete(pkt);
             return NULL;
         }
@@ -488,7 +488,7 @@ ipf_reassemble_v6_frags(struct ipf_list *ipf_list)
         pl += add_len;
         if (pl > IPV6_PACKET_MAX_DATA) {
             ipf_print_reass_packet(
-                "Unsupported big reassmbled v6 packet; v6 hdr:", l3);
+                "Unsupported big reassembled v6 packet; v6 hdr:", l3);
             dp_packet_delete(pkt);
             return NULL;
         }
@@ -510,7 +510,7 @@ ipf_reassemble_v6_frags(struct ipf_list *ipf_list)
     if (!parse_ipv6_ext_hdrs(&data, &datasize, &nw_proto, &nw_frag, &frag_hdr)
         || !nw_frag || !frag_hdr) {
 
-        ipf_print_reass_packet("Unparsed reassmbled v6 packet; v6 hdr:", l3);
+        ipf_print_reass_packet("Unparsed reassembled v6 packet; v6 hdr:", l3);
         dp_packet_delete(pkt);
         return NULL;
     }
@@ -594,32 +594,25 @@ ipf_list_state_transition(struct ipf_list *ipf_list, bool ff, bool lf,
     ipf_list->state = next_state;
 }
 
-static bool
-ipf_return_invalid(struct dp_packet *pkt)
-{
-    pkt->md.ct_state = CS_INVALID;
-    return false;
-}
-
 static bool
 ipf_is_valid_v4_frag(struct dp_packet *pkt)
 {
     if (OVS_UNLIKELY(dp_packet_ip_checksum_bad(pkt))) {
-        return ipf_return_invalid(pkt);
+        goto invalid_pkt;
     }
 
     const struct eth_header *l2 = dp_packet_eth(pkt);
     const struct ip_header *l3 = dp_packet_l3(pkt);
 
     if (OVS_UNLIKELY(!l2 || !l3)) {
-        return ipf_return_invalid(pkt);
+        goto invalid_pkt;
     }
 
     const char *tail = dp_packet_tail(pkt);
     uint8_t pad = dp_packet_l2_pad_size(pkt);
     size_t size = tail - (char *)l3 - pad;
     if (OVS_UNLIKELY(size < IP_HEADER_LEN)) {
-        return ipf_return_invalid(pkt);
+        goto invalid_pkt;
     }
 
     if (!(IP_IS_FRAGMENT(l3->ip_frag_off))) {
@@ -628,20 +621,20 @@ ipf_is_valid_v4_frag(struct dp_packet *pkt)
 
     uint16_t ip_tot_len = ntohs(l3->ip_tot_len);
     if (OVS_UNLIKELY(ip_tot_len != size)) {
-        return ipf_return_invalid(pkt);
+        goto invalid_pkt;
     }
 
     size_t ip_hdr_len = IP_IHL(l3->ip_ihl_ver) * 4;
     if (OVS_UNLIKELY(ip_hdr_len < IP_HEADER_LEN)) {
-        return ipf_return_invalid(pkt);
+        goto invalid_pkt;
     }
     if (OVS_UNLIKELY(size < ip_hdr_len)) {
-        return ipf_return_invalid(pkt);
+        goto invalid_pkt;
     }
 
     if (OVS_UNLIKELY(!dp_packet_ip_checksum_valid(pkt)
                      && csum(l3, ip_hdr_len) != 0)) {
-        return ipf_return_invalid(pkt);
+        goto invalid_pkt;
     }
 
     uint32_t min_v4_frag_size_;
@@ -649,9 +642,13 @@ ipf_is_valid_v4_frag(struct dp_packet *pkt)
     bool lf = ipf_is_last_v4_frag(pkt);
     if (OVS_UNLIKELY(!lf && dp_packet_size(pkt) < min_v4_frag_size_)) {
         ipf_count(false, IPF_COUNTER_NFRAGS_TOO_SMALL);
-        return ipf_return_invalid(pkt);
+        goto invalid_pkt;
     }
     return true;
+
+invalid_pkt:
+    pkt->md.ct_state = CS_INVALID;
+    return false;
 }
 
 static bool
@@ -686,7 +683,7 @@ ipf_is_valid_v6_frag(struct dp_packet *pkt OVS_UNUSED)
     const char *l4 = dp_packet_l4(pkt);
 
     if (OVS_UNLIKELY(!l2 || !l3 || !l4)) {
-        return ipf_return_invalid(pkt);
+        goto invalid_pkt;
     }
 
     const char *tail = dp_packet_tail(pkt);
@@ -695,7 +692,7 @@ ipf_is_valid_v6_frag(struct dp_packet *pkt OVS_UNUSED)
     size_t l3_hdr_size = sizeof *l3;
 
     if (OVS_UNLIKELY(l3_size < l3_hdr_size)) {
-        return ipf_return_invalid(pkt);
+        goto invalid_pkt;
     }
 
     uint8_t nw_frag = 0;
@@ -710,7 +707,7 @@ ipf_is_valid_v6_frag(struct dp_packet *pkt OVS_UNUSED)
 
     int pl = ntohs(l3->ip6_plen);
     if (OVS_UNLIKELY(pl + l3_hdr_size != l3_size)) {
-        return ipf_return_invalid(pkt);
+        goto invalid_pkt;
     }
 
     ovs_be16 ip6f_offlg = frag_hdr->ip6f_offlg;
@@ -724,10 +721,14 @@ ipf_is_valid_v6_frag(struct dp_packet *pkt OVS_UNUSED)
 
     if (OVS_UNLIKELY(!lf && dp_packet_size(pkt) < min_v6_frag_size_)) {
         ipf_count(true, IPF_COUNTER_NFRAGS_TOO_SMALL);
-        return ipf_return_invalid(pkt);
+        goto invalid_pkt;
     }
 
     return true;
+
+invalid_pkt:
+    pkt->md.ct_state = CS_INVALID;
+    return false;
 }
 
 static void
@@ -983,6 +984,7 @@ ipf_dp_packet_batch_add(struct dp_packet_batch *pb , struct dp_packet *pkt,
  * reason known right now is a mempool source check, which exists due to DPDK
  * support, where packets are no longer being received on any port with a
  * source matching the fragment.
+ *
  * Returns true if the list was purged. */
 static bool
 ipf_purge_list_check(struct ipf_list *ipf_list, long long now)
@@ -1201,7 +1203,7 @@ ipf_post_execute_reass_pkts(struct dp_packet_batch *pb, bool v6)
 
 /* Extracts any fragments from the batch and reassembles them when a
  * complete packet is received.  Completed packets are attempted to
- * be added to the batch to be sent thru. conntrack. */
+ * be added to the batch to be sent through conntrack. */
 void
 ipf_preprocess_conntrack(struct dp_packet_batch *pb, long long now,
                          ovs_be16 dl_type, uint16_t zone, uint32_t hash_basis)
@@ -1216,7 +1218,7 @@ ipf_preprocess_conntrack(struct dp_packet_batch *pb, long long now,
 }
 
 /* Updates fragments based on the processing of the reassembled packet sent
- * thru. conntrack and adds these fragments to any batches seen.  Expired
+ * through conntrack and adds these fragments to any batches seen.  Expired
  * fragments are marked as invalid and also added to the batches seen
  * with low priority.  Reassembled packets are freed. */
 void
diff --git a/lib/ipf.h b/lib/ipf.h
index 212d1b3458f9..040031f0190c 100644
--- a/lib/ipf.h
+++ b/lib/ipf.h
@@ -20,41 +20,14 @@
 #include "dp-packet.h"
 #include "openvswitch/types.h"
 
-struct ipf_status {
-   bool ifp_v4_enabled;
-   unsigned int min_v4_frag_size;
-   unsigned int nfrag_max;
-   unsigned int nfrag;
-   unsigned int n4frag_accepted;
-   unsigned int n4frag_completed_sent;
-   unsigned int n4frag_expired_sent;
-   unsigned int n4frag_too_small;
-   unsigned int n4frag_overlap;
-   bool ifp_v6_enabled;
-   unsigned int min_v6_frag_size;
-   unsigned int n6frag_accepted;
-   unsigned int n6frag_completed_sent;
-   unsigned int n6frag_expired_sent;
-   unsigned int n6frag_too_small;
-   unsigned int n6frag_overlap;
-};
-
-/* Collects and reassembles fragments which are to be sent through
- * conntrack, if fragment processing is enabled or fragments are
- * in flight. */
 void ipf_preprocess_conntrack(struct dp_packet_batch *pb, long long now,
                               ovs_be16 dl_type, uint16_t zone,
                               uint32_t hash_basis);
 
-/* Updates the state of fragments associated with reassembled packets and
- * sends out fragments that are either associated with completed
- * packets or expired, if fragment processing is enabled or fragments are
- * in flight. */
 void ipf_postprocess_conntrack(struct dp_packet_batch *pb, long long now,
                                ovs_be16 dl_type);
 
 void ipf_init(void);
-
 void ipf_destroy(void);
 
 #endif /* ipf.h */
diff --git a/tests/system-traffic.at b/tests/system-traffic.at
index 556a6a0db2d0..822122093944 100644
--- a/tests/system-traffic.at
+++ b/tests/system-traffic.at
@@ -2140,7 +2140,7 @@ packet-out in_port=1, packet=50540000000a505400000009080045000030000100310011a48
 ])
 
 AT_CHECK([ovs-ofctl bundle br0 bundle.txt])
-# There is one byte of overlap, hence the no packet gets thru. conntrack.
+# There is one byte of overlap, hence the no packet gets through conntrack.
 AT_CHECK([ovs-appctl dpctl/dump-conntrack | FORMAT_CT(10.1.1.2)], [0], [dnl
 ])
 
@@ -2164,7 +2164,7 @@ packet-out in_port=1, packet=50540000000a5054000000090800450001a4000120000011834
 ])
 
 AT_CHECK([ovs-ofctl bundle br0 bundle.txt])
-# There is one byte of overlap, hence the no packet gets thru. conntrack.
+# There is one byte of overlap, hence the no packet gets through conntrack.
 AT_CHECK([ovs-appctl dpctl/dump-conntrack | FORMAT_CT(10.1.1.2)], [0], [dnl
 ])
Darrell Ball Aug. 17, 2018, 6:17 a.m. | #2
On Wed, Aug 1, 2018 at 2:36 AM, Justin Pettit <jpettit@ovn.org> wrote:

>
> > On Jul 16, 2018, at 7:39 PM, Darrell Ball <dlu998@gmail.com> wrote:
> >
> > +static void
> > +ipf_expiry_list_add(struct ipf_list *ipf_list, long long now)
> > +    OVS_REQUIRES(ipf_lock)
> > +{
> > +    enum {
> > +        IPF_FRAG_LIST_TIMEOUT_DEFAULT = 15000,
> > +    };
> > +
> > +    ipf_list->expiration = now + IPF_FRAG_LIST_TIMEOUT_DEFAULT;
> > +    ovs_list_push_back(&frag_exp_list, &ipf_list->list_node);
> > +}
>
> This was brought up in the previous review, and I think we should drop
> "_DEFAULT", since it's not configurable.
>

Thats right; I was in the process of updating it along with some other
changes and it slipped back in.



>
> > +static bool
> > +ipf_return_invalid(struct dp_packet *pkt)
> > +{
> > +    pkt->md.ct_state = CS_INVALID;
> > +    return false;
> > +}
>
> This function looks kind of odd to me.  I think the same thing could be
> accomplished more clearly with a goto in the functions that need it.  I've
> implemented it in my incremental, below.
>

I realize OVS does not use these types of error functions and I have used
'goto' syntax myself repeatedly in OVS and it is perfectly fine.
I'll update to use 'goto'



>
> > +
> > +static bool
> > +ipf_is_valid_v4_frag(struct dp_packet *pkt)
> > +{
> > +    if (OVS_UNLIKELY(dp_packet_ip_checksum_bad(pkt))) {
> > +        return ipf_return_invalid(pkt);
> > +    }
>
> Do you think it would make sense to provide a counter when a packet gets
> marked as invalid?
>

It is a separate series across conntrack and ipf.



>
> > +static void
> > +ipf_extract_frags_from_batch(struct dp_packet_batch *pb, ovs_be16
> dl_type,
> > +                             uint16_t zone, long long now, uint32_t
> hash_basis)
> > +{
> > +    const size_t pb_cnt = dp_packet_batch_size(pb);
> > +    int pb_idx; /* Index in a packet batch. */
> > +    struct dp_packet *pkt;
> > +
> > +    DP_PACKET_BATCH_REFILL_FOR_EACH (pb_idx, pb_cnt, pkt, pb) {
> > +
> > +        if (OVS_UNLIKELY((dl_type == htons(ETH_TYPE_IP) &&
> > +                          ipf_is_valid_v4_frag(pkt)) ||
> > +                         (dl_type == htons(ETH_TYPE_IPV6) &&
> > +                          ipf_is_valid_v6_frag(pkt)))) {
>
> Is this case unlikely?
>

Yes, fragments are unlikely overall.



>
> > diff --git a/lib/ipf.h b/lib/ipf.h
> > new file mode 100644
> > index 0000000..212d1b3
> > --- /dev/null
> > +++ b/lib/ipf.h
> > ...
> > +struct ipf_status {
> > +   bool ifp_v4_enabled;
> > +   unsigned int min_v4_frag_size;
> > +   unsigned int nfrag_max;
> > +   unsigned int nfrag;
> > +   unsigned int n4frag_accepted;
> > +   unsigned int n4frag_completed_sent;
> > +   unsigned int n4frag_expired_sent;
> > +   unsigned int n4frag_too_small;
> > +   unsigned int n4frag_overlap;
> > +   bool ifp_v6_enabled;
> > +   unsigned int min_v6_frag_size;
> > +   unsigned int n6frag_accepted;
> > +   unsigned int n6frag_completed_sent;
> > +   unsigned int n6frag_expired_sent;
> > +   unsigned int n6frag_too_small;
> > +   unsigned int n6frag_overlap;
> > +};
>
> This isn't used until a later patch.  Let's wait to introduce it until
> then.
>

For sure.



>
> > +/* Collects and reassembles fragments which are to be sent through
> > + * conntrack, if fragment processing is enabled or fragments are
> > + * in flight. */
> > +void ipf_preprocess_conntrack(struct dp_packet_batch *pb, long long
> now,
> > +                              ovs_be16 dl_type, uint16_t zone,
> > +                              uint32_t hash_basis);
> > +
> > +/* Updates the state of fragments associated with reassembled packets
> and
> > + * sends out fragments that are either associated with completed
> > + * packets or expired, if fragment processing is enabled or fragments
> are
> > + * in flight. */
> > +void ipf_postprocess_conntrack(struct dp_packet_batch *pb, long long
> now,
> > +                               ovs_be16 dl_type);
>
> These functions are also described in "ipf.c".  Let's just use the ones
> there so that we don't have to worry about them drifting apart.
>

thats fine with me



>
> I'd like to commit it with the incremental at the bottom of this message.
>

I will fold in.

Thank you for all those fixups.

I would like to defer one - the update for 'thru.' -> 'through' in
system-traffic.at for now to avoid
the long line thingy.




>
> --Justin
>
>
> -=-=-=-=-=-=-=-=-=-=-
>
> diff --git a/lib/ipf.c b/lib/ipf.c
> index 1169a8a5e60c..bb2e2d692036 100644
> --- a/lib/ipf.c
> +++ b/lib/ipf.c
> @@ -106,12 +106,12 @@ struct ipf_list {
>      struct ovs_list list_node;
>      struct ipf_frag *frag_list;
>      struct ipf_list_key key;
> -    struct dp_packet *reass_execute_ctx; /* reassembled packet. */
> -    long long expiration;
> -    int last_sent_idx;               /* last sent fragment idx. */
> -    int last_inuse_idx;             /* last inuse fragment idx. */
> -    int size;                            /* fragment list size. */
> -    uint8_t state;      /* frag list state; see ipf_list_state. */
> +    struct dp_packet *reass_execute_ctx; /* Reassembled packet. */
> +    long long expiration;          /* In milliseconds. */
> +    int last_sent_idx;             /* Last sent fragment idx. */
> +    int last_inuse_idx;            /* Last inuse fragment idx. */
> +    int size;                      /* Fragment list size. */
> +    uint8_t state;                 /* Frag list state; see
> ipf_list_state. */
>  };
>
>  struct reassembled_pkt {
> @@ -266,10 +266,10 @@ ipf_expiry_list_add(struct ipf_list *ipf_list, long
> long now)
>      OVS_REQUIRES(ipf_lock)
>  {
>      enum {
> -        IPF_FRAG_LIST_TIMEOUT_DEFAULT = 15000,
> +        IPF_FRAG_LIST_TIMEOUT = 15000,
>      };
>
> -    ipf_list->expiration = now + IPF_FRAG_LIST_TIMEOUT_DEFAULT;
> +    ipf_list->expiration = now + IPF_FRAG_LIST_TIMEOUT;
>      ovs_list_push_back(&frag_exp_list, &ipf_list->list_node);
>  }
>
> @@ -447,7 +447,7 @@ ipf_reassemble_v4_frags(struct ipf_list *ipf_list)
>          len += add_len;
>          if (len > IPV4_PACKET_MAX_SIZE) {
>              ipf_print_reass_packet(
> -                "Unsupported big reassmbled v4 packet; v4 hdr:", l3);
> +                "Unsupported big reassembled v4 packet; v4 hdr:", l3);
>              dp_packet_delete(pkt);
>              return NULL;
>          }
> @@ -488,7 +488,7 @@ ipf_reassemble_v6_frags(struct ipf_list *ipf_list)
>          pl += add_len;
>          if (pl > IPV6_PACKET_MAX_DATA) {
>              ipf_print_reass_packet(
> -                "Unsupported big reassmbled v6 packet; v6 hdr:", l3);
> +                "Unsupported big reassembled v6 packet; v6 hdr:", l3);
>              dp_packet_delete(pkt);
>              return NULL;
>          }
> @@ -510,7 +510,7 @@ ipf_reassemble_v6_frags(struct ipf_list *ipf_list)
>      if (!parse_ipv6_ext_hdrs(&data, &datasize, &nw_proto, &nw_frag,
> &frag_hdr)
>          || !nw_frag || !frag_hdr) {
>
> -        ipf_print_reass_packet("Unparsed reassmbled v6 packet; v6 hdr:",
> l3);
> +        ipf_print_reass_packet("Unparsed reassembled v6 packet; v6
> hdr:", l3);
>          dp_packet_delete(pkt);
>          return NULL;
>      }
> @@ -594,32 +594,25 @@ ipf_list_state_transition(struct ipf_list
> *ipf_list, bool ff, bool lf,
>      ipf_list->state = next_state;
>  }
>
> -static bool
> -ipf_return_invalid(struct dp_packet *pkt)
> -{
> -    pkt->md.ct_state = CS_INVALID;
> -    return false;
> -}
> -
>  static bool
>  ipf_is_valid_v4_frag(struct dp_packet *pkt)
>  {
>      if (OVS_UNLIKELY(dp_packet_ip_checksum_bad(pkt))) {
> -        return ipf_return_invalid(pkt);
> +        goto invalid_pkt;
>      }
>
>      const struct eth_header *l2 = dp_packet_eth(pkt);
>      const struct ip_header *l3 = dp_packet_l3(pkt);
>
>      if (OVS_UNLIKELY(!l2 || !l3)) {
> -        return ipf_return_invalid(pkt);
> +        goto invalid_pkt;
>      }
>
>      const char *tail = dp_packet_tail(pkt);
>      uint8_t pad = dp_packet_l2_pad_size(pkt);
>      size_t size = tail - (char *)l3 - pad;
>      if (OVS_UNLIKELY(size < IP_HEADER_LEN)) {
> -        return ipf_return_invalid(pkt);
> +        goto invalid_pkt;
>      }
>
>      if (!(IP_IS_FRAGMENT(l3->ip_frag_off))) {
> @@ -628,20 +621,20 @@ ipf_is_valid_v4_frag(struct dp_packet *pkt)
>
>      uint16_t ip_tot_len = ntohs(l3->ip_tot_len);
>      if (OVS_UNLIKELY(ip_tot_len != size)) {
> -        return ipf_return_invalid(pkt);
> +        goto invalid_pkt;
>      }
>
>      size_t ip_hdr_len = IP_IHL(l3->ip_ihl_ver) * 4;
>      if (OVS_UNLIKELY(ip_hdr_len < IP_HEADER_LEN)) {
> -        return ipf_return_invalid(pkt);
> +        goto invalid_pkt;
>      }
>      if (OVS_UNLIKELY(size < ip_hdr_len)) {
> -        return ipf_return_invalid(pkt);
> +        goto invalid_pkt;
>      }
>
>      if (OVS_UNLIKELY(!dp_packet_ip_checksum_valid(pkt)
>                       && csum(l3, ip_hdr_len) != 0)) {
> -        return ipf_return_invalid(pkt);
> +        goto invalid_pkt;
>      }
>
>      uint32_t min_v4_frag_size_;
> @@ -649,9 +642,13 @@ ipf_is_valid_v4_frag(struct dp_packet *pkt)
>      bool lf = ipf_is_last_v4_frag(pkt);
>      if (OVS_UNLIKELY(!lf && dp_packet_size(pkt) < min_v4_frag_size_)) {
>          ipf_count(false, IPF_COUNTER_NFRAGS_TOO_SMALL);
> -        return ipf_return_invalid(pkt);
> +        goto invalid_pkt;
>      }
>      return true;
> +
> +invalid_pkt:
> +    pkt->md.ct_state = CS_INVALID;
> +    return false;
>  }
>
>  static bool
> @@ -686,7 +683,7 @@ ipf_is_valid_v6_frag(struct dp_packet *pkt OVS_UNUSED)
>      const char *l4 = dp_packet_l4(pkt);
>
>      if (OVS_UNLIKELY(!l2 || !l3 || !l4)) {
> -        return ipf_return_invalid(pkt);
> +        goto invalid_pkt;
>      }
>
>      const char *tail = dp_packet_tail(pkt);
> @@ -695,7 +692,7 @@ ipf_is_valid_v6_frag(struct dp_packet *pkt OVS_UNUSED)
>      size_t l3_hdr_size = sizeof *l3;
>
>      if (OVS_UNLIKELY(l3_size < l3_hdr_size)) {
> -        return ipf_return_invalid(pkt);
> +        goto invalid_pkt;
>      }
>
>      uint8_t nw_frag = 0;
> @@ -710,7 +707,7 @@ ipf_is_valid_v6_frag(struct dp_packet *pkt OVS_UNUSED)
>
>      int pl = ntohs(l3->ip6_plen);
>      if (OVS_UNLIKELY(pl + l3_hdr_size != l3_size)) {
> -        return ipf_return_invalid(pkt);
> +        goto invalid_pkt;
>      }
>
>      ovs_be16 ip6f_offlg = frag_hdr->ip6f_offlg;
> @@ -724,10 +721,14 @@ ipf_is_valid_v6_frag(struct dp_packet *pkt
> OVS_UNUSED)
>
>      if (OVS_UNLIKELY(!lf && dp_packet_size(pkt) < min_v6_frag_size_)) {
>          ipf_count(true, IPF_COUNTER_NFRAGS_TOO_SMALL);
> -        return ipf_return_invalid(pkt);
> +        goto invalid_pkt;
>      }
>
>      return true;
> +
> +invalid_pkt:
> +    pkt->md.ct_state = CS_INVALID;
> +    return false;
>  }
>
>  static void
> @@ -983,6 +984,7 @@ ipf_dp_packet_batch_add(struct dp_packet_batch *pb ,
> struct dp_packet *pkt,
>   * reason known right now is a mempool source check, which exists due to
> DPDK
>   * support, where packets are no longer being received on any port with a
>   * source matching the fragment.
> + *
>   * Returns true if the list was purged. */
>  static bool
>  ipf_purge_list_check(struct ipf_list *ipf_list, long long now)
> @@ -1201,7 +1203,7 @@ ipf_post_execute_reass_pkts(struct dp_packet_batch
> *pb, bool v6)
>
>  /* Extracts any fragments from the batch and reassembles them when a
>   * complete packet is received.  Completed packets are attempted to
> - * be added to the batch to be sent thru. conntrack. */
> + * be added to the batch to be sent through conntrack. */
>  void
>  ipf_preprocess_conntrack(struct dp_packet_batch *pb, long long now,
>                           ovs_be16 dl_type, uint16_t zone, uint32_t
> hash_basis)
> @@ -1216,7 +1218,7 @@ ipf_preprocess_conntrack(struct dp_packet_batch
> *pb, long long now,
>  }
>
>  /* Updates fragments based on the processing of the reassembled packet
> sent
> - * thru. conntrack and adds these fragments to any batches seen.  Expired
> + * through conntrack and adds these fragments to any batches seen.
> Expired
>   * fragments are marked as invalid and also added to the batches seen
>   * with low priority.  Reassembled packets are freed. */
>  void
> diff --git a/lib/ipf.h b/lib/ipf.h
> index 212d1b3458f9..040031f0190c 100644
> --- a/lib/ipf.h
> +++ b/lib/ipf.h
> @@ -20,41 +20,14 @@
>  #include "dp-packet.h"
>  #include "openvswitch/types.h"
>
> -struct ipf_status {
> -   bool ifp_v4_enabled;
> -   unsigned int min_v4_frag_size;
> -   unsigned int nfrag_max;
> -   unsigned int nfrag;
> -   unsigned int n4frag_accepted;
> -   unsigned int n4frag_completed_sent;
> -   unsigned int n4frag_expired_sent;
> -   unsigned int n4frag_too_small;
> -   unsigned int n4frag_overlap;
> -   bool ifp_v6_enabled;
> -   unsigned int min_v6_frag_size;
> -   unsigned int n6frag_accepted;
> -   unsigned int n6frag_completed_sent;
> -   unsigned int n6frag_expired_sent;
> -   unsigned int n6frag_too_small;
> -   unsigned int n6frag_overlap;
> -};
> -
> -/* Collects and reassembles fragments which are to be sent through
> - * conntrack, if fragment processing is enabled or fragments are
> - * in flight. */
>  void ipf_preprocess_conntrack(struct dp_packet_batch *pb, long long now,
>                                ovs_be16 dl_type, uint16_t zone,
>                                uint32_t hash_basis);
>
> -/* Updates the state of fragments associated with reassembled packets and
> - * sends out fragments that are either associated with completed
> - * packets or expired, if fragment processing is enabled or fragments are
> - * in flight. */
>  void ipf_postprocess_conntrack(struct dp_packet_batch *pb, long long now,
>                                 ovs_be16 dl_type);
>
>  void ipf_init(void);
> -
>  void ipf_destroy(void);
>
>  #endif /* ipf.h */
> diff --git a/tests/system-traffic.at b/tests/system-traffic.at
> index 556a6a0db2d0..822122093944 100644
> --- a/tests/system-traffic.at
> +++ b/tests/system-traffic.at
> @@ -2140,7 +2140,7 @@ packet-out in_port=1, packet=
> 50540000000a505400000009080045000030000100310011a48
>  ])
>
>  AT_CHECK([ovs-ofctl bundle br0 bundle.txt])
> -# There is one byte of overlap, hence the no packet gets thru. conntrack.
> +# There is one byte of overlap, hence the no packet gets through
> conntrack.
>  AT_CHECK([ovs-appctl dpctl/dump-conntrack | FORMAT_CT(10.1.1.2)], [0],
> [dnl
>  ])
>
> @@ -2164,7 +2164,7 @@ packet-out in_port=1, packet=
> 50540000000a5054000000090800450001a4000120000011834
>  ])
>
>  AT_CHECK([ovs-ofctl bundle br0 bundle.txt])
> -# There is one byte of overlap, hence the no packet gets thru. conntrack.
> +# There is one byte of overlap, hence the no packet gets through
> conntrack.
>  AT_CHECK([ovs-appctl dpctl/dump-conntrack | FORMAT_CT(10.1.1.2)], [0],
> [dnl
>  ])
>
>
I would like to defer the update to "thru." in system-traffic.at to avoid
the long line thingy.

Patch

diff --git a/NEWS b/NEWS
index 057e8bf..9c82234 100644
--- a/NEWS
+++ b/NEWS
@@ -14,6 +14,8 @@  Post-v2.9.0
      * ovs-ofctl now accepts and display table names in place of numbers.  By
        default it always accepts names and in interactive use it displays them;
        use --names or --no-names to override.  See ovs-ofctl(8) for details.
+   - Userspace datapath:
+     * Add v4/v6 fragmentation support for conntrack.
    - ovs-vsctl: New commands "add-bond-iface" and "del-bond-iface".
    - OpenFlow:
      * OFPT_ROLE_STATUS is now available in OpenFlow 1.3.
diff --git a/include/sparse/netinet/ip6.h b/include/sparse/netinet/ip6.h
index d2a54de..bfa637a 100644
--- a/include/sparse/netinet/ip6.h
+++ b/include/sparse/netinet/ip6.h
@@ -64,5 +64,6 @@  struct ip6_frag {
 };
 
 #define IP6F_OFF_MASK ((OVS_FORCE ovs_be16) 0xfff8)
+#define IP6F_MORE_FRAG ((OVS_FORCE ovs_be16) 0x0001)
 
 #endif /* netinet/ip6.h sparse */
diff --git a/lib/automake.mk b/lib/automake.mk
index fb43aa1..142587f 100644
--- a/lib/automake.mk
+++ b/lib/automake.mk
@@ -107,6 +107,8 @@  lib_libopenvswitch_la_SOURCES = \
 	lib/hmapx.h \
 	lib/id-pool.c \
 	lib/id-pool.h \
+	lib/ipf.c \
+	lib/ipf.h \
 	lib/jhash.c \
 	lib/jhash.h \
 	lib/json.c \
diff --git a/lib/conntrack.c b/lib/conntrack.c
index 3f50fc8..be8debb 100644
--- a/lib/conntrack.c
+++ b/lib/conntrack.c
@@ -30,6 +30,7 @@ 
 #include "ct-dpif.h"
 #include "dp-packet.h"
 #include "flow.h"
+#include "ipf.h"
 #include "netdev.h"
 #include "odp-netlink.h"
 #include "openvswitch/hmap.h"
@@ -339,6 +340,7 @@  conntrack_init(struct conntrack *ct)
     atomic_init(&ct->n_conn_limit, DEFAULT_N_CONN_LIMIT);
     latch_init(&ct->clean_thread_exit);
     ct->clean_thread = ovs_thread_create("ct_clean", clean_thread_main, ct);
+    ipf_init();
 }
 
 /* Destroys the connection tracker 'ct' and frees all the allocated memory. */
@@ -381,6 +383,7 @@  conntrack_destroy(struct conntrack *ct)
     hindex_destroy(&ct->alg_expectation_refs);
     ct_rwlock_unlock(&ct->resources_lock);
     ct_rwlock_destroy(&ct->resources_lock);
+    ipf_destroy();
 }
 
 static unsigned hash_to_bucket(uint32_t hash)
@@ -1295,7 +1298,8 @@  process_one(struct conntrack *ct, struct dp_packet *pkt,
 
 /* Sends the packets in '*pkt_batch' through the connection tracker 'ct'.  All
  * the packets must have the same 'dl_type' (IPv4 or IPv6) and should have
- * the l3 and and l4 offset properly set.
+ * the l3 and and l4 offset properly set.  Performs fragment reassembly with
+ * the help of ipf_preprocess_conntrack().
  *
  * If 'commit' is true, the packets are allowed to create new entries in the
  * connection tables.  'setmark', if not NULL, should point to a two
@@ -1310,11 +1314,14 @@  conntrack_execute(struct conntrack *ct, struct dp_packet_batch *pkt_batch,
                   const struct nat_action_info_t *nat_action_info,
                   long long now)
 {
+    ipf_preprocess_conntrack(pkt_batch, now, dl_type, zone, ct->hash_basis);
+
     struct dp_packet *packet;
     struct conn_lookup_ctx ctx;
 
     DP_PACKET_BATCH_FOR_EACH (i, packet, pkt_batch) {
-        if (!conn_key_extract(ct, packet, dl_type, &ctx, zone)) {
+        if (packet->md.ct_state == CS_INVALID
+            || !conn_key_extract(ct, packet, dl_type, &ctx, zone)) {
             packet->md.ct_state = CS_INVALID;
             write_ct_md(packet, zone, NULL, NULL, NULL);
             continue;
@@ -1323,6 +1330,8 @@  conntrack_execute(struct conntrack *ct, struct dp_packet_batch *pkt_batch,
                     setlabel, nat_action_info, tp_src, tp_dst, helper);
     }
 
+    ipf_postprocess_conntrack(pkt_batch, now, dl_type);
+
     return 0;
 }
 
diff --git a/lib/ipf.c b/lib/ipf.c
new file mode 100644
index 0000000..1169a8a
--- /dev/null
+++ b/lib/ipf.c
@@ -0,0 +1,1299 @@ 
+/*
+ * Copyright (c) 2018 Nicira, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <config.h>
+#include <ctype.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <netinet/in.h>
+#include <netinet/ip6.h>
+#include <netinet/icmp6.h>
+#include <string.h>
+
+#include "coverage.h"
+#include "csum.h"
+#include "ipf.h"
+#include "openvswitch/hmap.h"
+#include "openvswitch/vlog.h"
+#include "ovs-atomic.h"
+#include "packets.h"
+#include "util.h"
+
+VLOG_DEFINE_THIS_MODULE(ipf);
+COVERAGE_DEFINE(ipf_stuck_frag_list_purged);
+
+enum {
+    IPV4_PACKET_MAX_HDR_SIZE = 60,
+    IPV4_PACKET_MAX_SIZE = 65535,
+    IPV6_PACKET_MAX_DATA = 65535,
+};
+
+enum ipf_list_state {
+    IPF_LIST_STATE_UNUSED,
+    IPF_LIST_STATE_REASS_FAIL,
+    IPF_LIST_STATE_OTHER_SEEN,
+    IPF_LIST_STATE_FIRST_SEEN,
+    IPF_LIST_STATE_LAST_SEEN,
+    IPF_LIST_STATE_FIRST_LAST_SEEN,
+    IPF_LIST_STATE_COMPLETED,
+    IPF_LIST_STATE_NUM,
+};
+
+enum ipf_list_type {
+    IPF_FRAG_COMPLETED_LIST,
+    IPF_FRAG_EXPIRY_LIST,
+};
+
+enum {
+    IPF_INVALID_IDX = -1,
+    IPF_V4_FRAG_SIZE_LBOUND = 400,
+    IPF_V4_FRAG_SIZE_MIN_DEF = 1200,
+    IPF_V6_FRAG_SIZE_LBOUND = 400, /* Useful for testing. */
+    IPF_V6_FRAG_SIZE_MIN_DEF = 1280,
+    IPF_MAX_FRAGS_DEFAULT = 1000,
+    IPF_NFRAG_UBOUND = 5000,
+};
+
+enum ipf_counter_type {
+    IPF_COUNTER_NFRAGS,
+    IPF_COUNTER_NFRAGS_ACCEPTED,
+    IPF_COUNTER_NFRAGS_COMPL_SENT,
+    IPF_COUNTER_NFRAGS_EXPD_SENT,
+    IPF_COUNTER_NFRAGS_TOO_SMALL,
+    IPF_COUNTER_NFRAGS_OVERLAP,
+};
+
+struct ipf_addr {
+    union {
+        ovs_16aligned_be32 ipv4;
+        union ovs_16aligned_in6_addr ipv6;
+        ovs_be32 ipv4_aligned;
+        struct in6_addr ipv6_aligned;
+    };
+};
+
+struct ipf_frag {
+    struct dp_packet *pkt;
+    uint16_t start_data_byte;
+    uint16_t end_data_byte;
+};
+
+struct ipf_list_key {
+    struct ipf_addr src_addr;
+    struct ipf_addr dst_addr;
+    uint32_t recirc_id;
+    ovs_be32 ip_id;   /* V6 is 32 bits. */
+    ovs_be16 dl_type;
+    uint16_t zone;
+    uint8_t nw_proto;
+};
+
+struct ipf_list {
+    struct hmap_node node;
+    struct ovs_list list_node;
+    struct ipf_frag *frag_list;
+    struct ipf_list_key key;
+    struct dp_packet *reass_execute_ctx; /* reassembled packet. */
+    long long expiration;
+    int last_sent_idx;               /* last sent fragment idx. */
+    int last_inuse_idx;             /* last inuse fragment idx. */
+    int size;                            /* fragment list size. */
+    uint8_t state;      /* frag list state; see ipf_list_state. */
+};
+
+struct reassembled_pkt {
+    struct ovs_list rp_list_node;
+    struct dp_packet *pkt;
+    struct ipf_list *list;
+};
+
+struct OVS_LOCKABLE ipf_lock {
+    struct ovs_mutex lock;
+};
+
+static struct ipf_lock ipf_lock;
+
+static int max_v4_frag_list_size;
+
+static struct hmap frag_lists OVS_GUARDED_BY(ipf_lock);
+static struct ovs_list frag_exp_list OVS_GUARDED_BY(ipf_lock);
+static struct ovs_list frag_complete_list OVS_GUARDED_BY(ipf_lock);
+static struct ovs_list reassembled_pkt_list OVS_GUARDED_BY(ipf_lock);
+
+static atomic_bool ifp_v4_enabled;
+static atomic_bool ifp_v6_enabled;
+static atomic_uint nfrag_max;
+/* Will be clamped above 400 bytes; the value chosen should handle
+ * alg control packets of interest that use string encoding of mutable
+ * IP fields; meaning, the control packets should not be fragmented. */
+static atomic_uint min_v4_frag_size;
+static atomic_uint min_v6_frag_size;
+
+static atomic_count nfrag;
+static atomic_count n4frag_accepted;
+static atomic_count n4frag_completed_sent;
+static atomic_count n4frag_expired_sent;
+static atomic_count n4frag_too_small;
+static atomic_count n4frag_overlap;
+static atomic_count n6frag_accepted;
+static atomic_count n6frag_completed_sent;
+static atomic_count n6frag_expired_sent;
+static atomic_count n6frag_too_small;
+static atomic_count n6frag_overlap;
+
+static void
+ipf_print_reass_packet(char *es, void *pkt)
+{
+    const unsigned char *b = (const unsigned char *) pkt;
+    static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(10, 10);
+    VLOG_WARN_RL(&rl, "%s 91 bytes from specified part of packet "
+                 "%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X"
+                 "%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X"
+                 "%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X"
+                 "%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X"
+                 "%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X"
+                 "%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X"
+                 "%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X",
+                 es, b[0], b[1], b[2], b[3], b[4], b[5], b[6], b[7], b[8],
+                 b[9], b[10], b[11], b[12], b[13], b[14], b[15], b[16],
+                 b[17], b[18], b[19], b[20], b[21], b[22], b[23], b[24],
+                 b[25], b[26], b[27], b[28], b[29], b[30], b[31], b[32],
+                 b[33], b[34], b[35], b[36], b[37], b[38], b[39], b[40],
+                 b[41], b[42], b[43], b[44], b[45], b[46], b[47], b[48],
+                 b[49], b[50], b[51], b[52], b[53], b[54], b[55], b[56],
+                 b[57], b[58], b[59], b[60], b[61], b[62], b[63], b[64],
+                 b[65], b[66], b[67], b[68], b[69], b[70], b[71], b[72],
+                 b[73], b[74], b[75], b[76], b[77], b[77], b[79], b[80],
+                 b[81], b[82], b[83], b[84], b[85], b[86], b[87], b[88],
+                 b[89], b[90]);
+}
+
+static void ipf_lock_init(struct ipf_lock *lock)
+{
+    ovs_mutex_init_adaptive(&lock->lock);
+}
+
+static void ipf_lock_lock(struct ipf_lock *lock)
+    OVS_ACQUIRES(lock)
+    OVS_NO_THREAD_SAFETY_ANALYSIS
+{
+    ovs_mutex_lock(&lock->lock);
+}
+
+static void ipf_lock_unlock(struct ipf_lock *lock)
+    OVS_RELEASES(lock)
+    OVS_NO_THREAD_SAFETY_ANALYSIS
+{
+    ovs_mutex_unlock(&lock->lock);
+}
+
+static void ipf_lock_destroy(struct ipf_lock *lock)
+{
+    ovs_mutex_destroy(&lock->lock);
+}
+
+static void
+ipf_count(bool v6, enum ipf_counter_type cntr)
+{
+    switch (cntr) {
+    case IPF_COUNTER_NFRAGS_ACCEPTED:
+        atomic_count_inc(v6 ? &n6frag_accepted : &n4frag_accepted);
+        break;
+    case IPF_COUNTER_NFRAGS_COMPL_SENT:
+        atomic_count_inc(v6 ? &n6frag_completed_sent
+                         : &n4frag_completed_sent);
+        break;
+    case IPF_COUNTER_NFRAGS_EXPD_SENT:
+        atomic_count_inc(v6 ? &n6frag_expired_sent
+                         : &n4frag_expired_sent);
+        break;
+    case IPF_COUNTER_NFRAGS_TOO_SMALL:
+        atomic_count_inc(v6 ? &n6frag_too_small : &n4frag_too_small);
+        break;
+    case IPF_COUNTER_NFRAGS_OVERLAP:
+        atomic_count_inc(v6 ? &n6frag_overlap : &n4frag_overlap);
+        break;
+    case IPF_COUNTER_NFRAGS:
+    default:
+        OVS_NOT_REACHED();
+    }
+}
+
+static bool
+ipf_get_v4_enabled(void)
+{
+    bool ifp_v4_enabled_;
+    atomic_read_relaxed(&ifp_v4_enabled, &ifp_v4_enabled_);
+    return ifp_v4_enabled_;
+}
+
+static bool
+ipf_get_v6_enabled(void)
+{
+    bool ifp_v6_enabled_;
+    atomic_read_relaxed(&ifp_v6_enabled, &ifp_v6_enabled_);
+    return ifp_v6_enabled_;
+}
+
+static bool
+ipf_get_enabled(void)
+{
+    return ipf_get_v4_enabled() || ipf_get_v6_enabled();
+}
+
+static uint32_t
+ipf_addr_hash_add(uint32_t hash, const struct ipf_addr *addr)
+{
+    BUILD_ASSERT_DECL(sizeof *addr % 4 == 0);
+    return hash_add_bytes32(hash, (const uint32_t *) addr, sizeof *addr);
+}
+
+static void
+ipf_expiry_list_add(struct ipf_list *ipf_list, long long now)
+    OVS_REQUIRES(ipf_lock)
+{
+    enum {
+        IPF_FRAG_LIST_TIMEOUT_DEFAULT = 15000,
+    };
+
+    ipf_list->expiration = now + IPF_FRAG_LIST_TIMEOUT_DEFAULT;
+    ovs_list_push_back(&frag_exp_list, &ipf_list->list_node);
+}
+
+static void
+ipf_completed_list_add(struct ipf_list *ipf_list)
+    OVS_REQUIRES(ipf_lock)
+{
+    ovs_list_push_back(&frag_complete_list, &ipf_list->list_node);
+}
+
+static void
+ipf_reassembled_list_add(struct reassembled_pkt *rp)
+    OVS_REQUIRES(ipf_lock)
+{
+    ovs_list_push_back(&reassembled_pkt_list, &rp->rp_list_node);
+}
+
+static void
+ipf_list_clean(struct ipf_list *ipf_list)
+    OVS_REQUIRES(ipf_lock)
+{
+    ovs_list_remove(&ipf_list->list_node);
+    hmap_remove(&frag_lists, &ipf_list->node);
+    free(ipf_list->frag_list);
+    free(ipf_list);
+}
+
+static void
+ipf_expiry_list_clean(struct ipf_list *ipf_list)
+    OVS_REQUIRES(ipf_lock)
+{
+    ipf_list_clean(ipf_list);
+}
+
+static void
+ipf_completed_list_clean(struct ipf_list *ipf_list)
+    OVS_REQUIRES(ipf_lock)
+{
+    ipf_list_clean(ipf_list);
+}
+
+static void
+ipf_expiry_list_remove(struct ipf_list *ipf_list)
+    OVS_REQUIRES(ipf_lock)
+{
+    ovs_list_remove(&ipf_list->list_node);
+}
+
+static void
+ipf_reassembled_list_remove(struct reassembled_pkt *rp)
+    OVS_REQUIRES(ipf_lock)
+{
+    ovs_list_remove(&rp->rp_list_node);
+}
+
+/* Symmetric */
+static uint32_t
+ipf_list_key_hash(const struct ipf_list_key *key, uint32_t basis)
+{
+    uint32_t hsrc, hdst, hash;
+    hsrc = hdst = basis;
+    hsrc = ipf_addr_hash_add(hsrc, &key->src_addr);
+    hdst = ipf_addr_hash_add(hdst, &key->dst_addr);
+    hash = hsrc ^ hdst;
+
+    /* Hash the rest of the key. */
+    hash = hash_words((uint32_t *) (&key->dst_addr + 1),
+                      (uint32_t *) (key + 1) -
+                          (uint32_t *) (&key->dst_addr + 1),
+                      hash);
+
+    return hash_finish(hash, 0);
+}
+
+static bool
+ipf_is_first_v4_frag(const struct dp_packet *pkt)
+{
+    const struct ip_header *l3 = dp_packet_l3(pkt);
+    if (!(l3->ip_frag_off & htons(IP_FRAG_OFF_MASK)) &&
+        l3->ip_frag_off & htons(IP_MORE_FRAGMENTS)) {
+        return true;
+    }
+    return false;
+}
+
+static bool
+ipf_is_last_v4_frag(const struct dp_packet *pkt)
+{
+    const struct ip_header *l3 = dp_packet_l3(pkt);
+    if (l3->ip_frag_off & htons(IP_FRAG_OFF_MASK) &&
+        !(l3->ip_frag_off & htons(IP_MORE_FRAGMENTS))) {
+        return true;
+    }
+    return false;
+}
+
+static bool
+ipf_is_v6_frag(ovs_be16 ip6f_offlg)
+{
+    if (ip6f_offlg & (IP6F_OFF_MASK | IP6F_MORE_FRAG)) {
+        return true;
+    }
+    return false;
+}
+
+static bool
+ipf_is_first_v6_frag(ovs_be16 ip6f_offlg)
+{
+    if (!(ip6f_offlg & IP6F_OFF_MASK) &&
+        ip6f_offlg & IP6F_MORE_FRAG) {
+        return true;
+    }
+    return false;
+}
+
+static bool
+ipf_is_last_v6_frag(ovs_be16 ip6f_offlg)
+{
+    if ((ip6f_offlg & IP6F_OFF_MASK) &&
+        !(ip6f_offlg & IP6F_MORE_FRAG)) {
+        return true;
+    }
+    return false;
+}
+
+static bool
+ipf_list_complete(const struct ipf_list *ipf_list)
+    OVS_REQUIRES(ipf_lock)
+{
+    for (int i = 0; i < ipf_list->last_inuse_idx; i++) {
+        if (ipf_list->frag_list[i].end_data_byte + 1
+            != ipf_list->frag_list[i + 1].start_data_byte) {
+            return false;
+        }
+    }
+    return true;
+}
+
+/* Runs O(n) for a sorted or almost sorted list. */
+static void
+ipf_sort(struct ipf_frag *frag_list, size_t last_idx)
+    OVS_REQUIRES(ipf_lock)
+{
+    int running_last_idx = 1;
+    struct ipf_frag ipf_frag;
+    while (running_last_idx <= last_idx) {
+        ipf_frag = frag_list[running_last_idx];
+        int frag_list_idx = running_last_idx - 1;
+        while (frag_list_idx >= 0 &&
+               frag_list[frag_list_idx].start_data_byte >
+                   ipf_frag.start_data_byte) {
+            frag_list[frag_list_idx + 1] = frag_list[frag_list_idx];
+            frag_list_idx -= 1;
+        }
+        frag_list[frag_list_idx + 1] = ipf_frag;
+        running_last_idx++;
+    }
+}
+
+/* Called on a sorted complete list of fragments. */
+static struct dp_packet *
+ipf_reassemble_v4_frags(struct ipf_list *ipf_list)
+    OVS_REQUIRES(ipf_lock)
+{
+    struct ipf_frag *frag_list = ipf_list->frag_list;
+    struct dp_packet *pkt = dp_packet_clone(frag_list[0].pkt);
+    struct ip_header *l3 = dp_packet_l3(pkt);
+    int len = ntohs(l3->ip_tot_len);
+    size_t add_len;
+    size_t ip_hdr_len = IP_IHL(l3->ip_ihl_ver) * 4;
+
+    for (int i = 1; i <= ipf_list->last_inuse_idx; i++) {
+        add_len = frag_list[i].end_data_byte -
+                         frag_list[i].start_data_byte + 1;
+        len += add_len;
+        if (len > IPV4_PACKET_MAX_SIZE) {
+            ipf_print_reass_packet(
+                "Unsupported big reassmbled v4 packet; v4 hdr:", l3);
+            dp_packet_delete(pkt);
+            return NULL;
+        }
+        l3 = dp_packet_l3(frag_list[i].pkt);
+        dp_packet_put(pkt, (char *)l3 + ip_hdr_len, add_len);
+    }
+    l3 = dp_packet_l3(pkt);
+    ovs_be16 new_ip_frag_off = l3->ip_frag_off & ~htons(IP_MORE_FRAGMENTS);
+    l3->ip_csum = recalc_csum16(l3->ip_csum, l3->ip_frag_off,
+                                new_ip_frag_off);
+    l3->ip_csum = recalc_csum16(l3->ip_csum, l3->ip_tot_len, htons(len));
+    l3->ip_tot_len = htons(len);
+    l3->ip_frag_off = new_ip_frag_off;
+
+    return pkt;
+}
+
+/* Called on a sorted complete list of fragments. */
+static struct dp_packet *
+ipf_reassemble_v6_frags(struct ipf_list *ipf_list)
+    OVS_REQUIRES(ipf_lock)
+{
+    struct ipf_frag *frag_list = ipf_list->frag_list;
+    struct dp_packet *pkt = dp_packet_clone(frag_list[0].pkt);
+    struct  ovs_16aligned_ip6_hdr *l3 = dp_packet_l3(pkt);
+    int pl = ntohs(l3->ip6_plen) - sizeof(struct ovs_16aligned_ip6_frag);
+    const char *tail = dp_packet_tail(pkt);
+    uint8_t pad = dp_packet_l2_pad_size(pkt);
+    const char *l4 = dp_packet_l4(pkt);
+    size_t l3_size = tail - (char *)l3 - pad;
+    size_t l4_size = tail - (char *)l4 - pad;
+    size_t l3_hlen = l3_size - l4_size;
+    size_t add_len;
+
+    for (int i = 1; i <= ipf_list->last_inuse_idx; i++) {
+        add_len = frag_list[i].end_data_byte -
+                          frag_list[i].start_data_byte + 1;
+        pl += add_len;
+        if (pl > IPV6_PACKET_MAX_DATA) {
+            ipf_print_reass_packet(
+                "Unsupported big reassmbled v6 packet; v6 hdr:", l3);
+            dp_packet_delete(pkt);
+            return NULL;
+        }
+        l3 = dp_packet_l3(frag_list[i].pkt);
+        dp_packet_put(pkt, (char *)l3 + l3_hlen, add_len);
+    }
+    l3 = dp_packet_l3(pkt);
+    l4 = dp_packet_l4(pkt);
+    tail = dp_packet_tail(pkt);
+    pad = dp_packet_l2_pad_size(pkt);
+    l3_size = tail - (char *)l3 - pad;
+
+    uint8_t nw_proto = l3->ip6_nxt;
+    uint8_t nw_frag = 0;
+    const void *data = l3 + 1;
+    size_t datasize = l3_size - sizeof *l3;
+
+    const struct ovs_16aligned_ip6_frag *frag_hdr = NULL;
+    if (!parse_ipv6_ext_hdrs(&data, &datasize, &nw_proto, &nw_frag, &frag_hdr)
+        || !nw_frag || !frag_hdr) {
+
+        ipf_print_reass_packet("Unparsed reassmbled v6 packet; v6 hdr:", l3);
+        dp_packet_delete(pkt);
+        return NULL;
+    }
+
+    struct ovs_16aligned_ip6_frag *fh =
+        CONST_CAST(struct ovs_16aligned_ip6_frag *, frag_hdr);
+    fh->ip6f_offlg = 0;
+    l3->ip6_plen = htons(pl);
+    l3->ip6_ctlun.ip6_un1.ip6_un1_nxt = nw_proto;
+    return pkt;
+}
+
+/* Called when a valid fragment is added. */
+static void
+ipf_list_state_transition(struct ipf_list *ipf_list, bool ff, bool lf,
+                          bool v6)
+    OVS_REQUIRES(ipf_lock)
+{
+    enum ipf_list_state curr_state = ipf_list->state;
+    enum ipf_list_state next_state;
+    switch (curr_state) {
+    case IPF_LIST_STATE_UNUSED:
+    case IPF_LIST_STATE_OTHER_SEEN:
+        if (ff) {
+            next_state = IPF_LIST_STATE_FIRST_SEEN;
+        } else if (lf) {
+            next_state = IPF_LIST_STATE_LAST_SEEN;
+        } else {
+            next_state = IPF_LIST_STATE_OTHER_SEEN;
+        }
+        break;
+    case IPF_LIST_STATE_FIRST_SEEN:
+        if (ff) {
+            next_state = IPF_LIST_STATE_FIRST_SEEN;
+        } else if (lf) {
+            next_state = IPF_LIST_STATE_FIRST_LAST_SEEN;
+        } else {
+            next_state = IPF_LIST_STATE_FIRST_SEEN;
+        }
+        break;
+    case IPF_LIST_STATE_LAST_SEEN:
+        if (ff) {
+            next_state = IPF_LIST_STATE_FIRST_LAST_SEEN;
+        } else if (lf) {
+            next_state = IPF_LIST_STATE_LAST_SEEN;
+        } else {
+            next_state = IPF_LIST_STATE_LAST_SEEN;
+        }
+        break;
+    case IPF_LIST_STATE_FIRST_LAST_SEEN:
+        next_state = IPF_LIST_STATE_FIRST_LAST_SEEN;
+        break;
+    case IPF_LIST_STATE_COMPLETED:
+    case IPF_LIST_STATE_REASS_FAIL:
+    case IPF_LIST_STATE_NUM:
+    default:
+        OVS_NOT_REACHED();
+    }
+
+    if (next_state == IPF_LIST_STATE_FIRST_LAST_SEEN) {
+        ipf_sort(ipf_list->frag_list, ipf_list->last_inuse_idx);
+        if (ipf_list_complete(ipf_list)) {
+            struct dp_packet *reass_pkt = NULL;
+            if (v6) {
+                reass_pkt = ipf_reassemble_v6_frags(ipf_list);
+            } else {
+                reass_pkt = ipf_reassemble_v4_frags(ipf_list);
+            }
+            if (reass_pkt) {
+                struct reassembled_pkt *rp = xzalloc(sizeof *rp);
+                rp->pkt = reass_pkt;
+                rp->list = ipf_list;
+                ipf_reassembled_list_add(rp);
+                ipf_expiry_list_remove(ipf_list);
+                next_state = IPF_LIST_STATE_COMPLETED;
+            } else {
+                next_state = IPF_LIST_STATE_REASS_FAIL;
+            }
+        }
+    }
+    ipf_list->state = next_state;
+}
+
+static bool
+ipf_return_invalid(struct dp_packet *pkt)
+{
+    pkt->md.ct_state = CS_INVALID;
+    return false;
+}
+
+static bool
+ipf_is_valid_v4_frag(struct dp_packet *pkt)
+{
+    if (OVS_UNLIKELY(dp_packet_ip_checksum_bad(pkt))) {
+        return ipf_return_invalid(pkt);
+    }
+
+    const struct eth_header *l2 = dp_packet_eth(pkt);
+    const struct ip_header *l3 = dp_packet_l3(pkt);
+
+    if (OVS_UNLIKELY(!l2 || !l3)) {
+        return ipf_return_invalid(pkt);
+    }
+
+    const char *tail = dp_packet_tail(pkt);
+    uint8_t pad = dp_packet_l2_pad_size(pkt);
+    size_t size = tail - (char *)l3 - pad;
+    if (OVS_UNLIKELY(size < IP_HEADER_LEN)) {
+        return ipf_return_invalid(pkt);
+    }
+
+    if (!(IP_IS_FRAGMENT(l3->ip_frag_off))) {
+        return false;
+    }
+
+    uint16_t ip_tot_len = ntohs(l3->ip_tot_len);
+    if (OVS_UNLIKELY(ip_tot_len != size)) {
+        return ipf_return_invalid(pkt);
+    }
+
+    size_t ip_hdr_len = IP_IHL(l3->ip_ihl_ver) * 4;
+    if (OVS_UNLIKELY(ip_hdr_len < IP_HEADER_LEN)) {
+        return ipf_return_invalid(pkt);
+    }
+    if (OVS_UNLIKELY(size < ip_hdr_len)) {
+        return ipf_return_invalid(pkt);
+    }
+
+    if (OVS_UNLIKELY(!dp_packet_ip_checksum_valid(pkt)
+                     && csum(l3, ip_hdr_len) != 0)) {
+        return ipf_return_invalid(pkt);
+    }
+
+    uint32_t min_v4_frag_size_;
+    atomic_read_relaxed(&min_v4_frag_size, &min_v4_frag_size_);
+    bool lf = ipf_is_last_v4_frag(pkt);
+    if (OVS_UNLIKELY(!lf && dp_packet_size(pkt) < min_v4_frag_size_)) {
+        ipf_count(false, IPF_COUNTER_NFRAGS_TOO_SMALL);
+        return ipf_return_invalid(pkt);
+    }
+    return true;
+}
+
+static bool
+ipf_v4_key_extract(struct dp_packet *pkt, ovs_be16 dl_type, uint16_t zone,
+                   struct ipf_list_key *key, uint16_t *start_data_byte,
+                   uint16_t *end_data_byte, bool *ff, bool *lf)
+{
+    const struct ip_header *l3 = dp_packet_l3(pkt);
+    uint16_t ip_tot_len = ntohs(l3->ip_tot_len);
+    size_t ip_hdr_len = IP_IHL(l3->ip_ihl_ver) * 4;
+
+    *start_data_byte = ntohs(l3->ip_frag_off & htons(IP_FRAG_OFF_MASK)) * 8;
+    *end_data_byte = *start_data_byte + ip_tot_len - ip_hdr_len - 1;
+    *ff = ipf_is_first_v4_frag(pkt);
+    *lf = ipf_is_last_v4_frag(pkt);
+    memset(key, 0, sizeof *key);
+    key->ip_id = be16_to_be32(l3->ip_id);
+    key->dl_type = dl_type;
+    key->src_addr.ipv4 = l3->ip_src;
+    key->dst_addr.ipv4 = l3->ip_dst;
+    key->nw_proto = l3->ip_proto;
+    key->zone = zone;
+    key->recirc_id = pkt->md.recirc_id;
+    return true;
+}
+
+static bool
+ipf_is_valid_v6_frag(struct dp_packet *pkt OVS_UNUSED)
+{
+    const struct eth_header *l2 = dp_packet_eth(pkt);
+    const struct  ovs_16aligned_ip6_hdr *l3 = dp_packet_l3(pkt);
+    const char *l4 = dp_packet_l4(pkt);
+
+    if (OVS_UNLIKELY(!l2 || !l3 || !l4)) {
+        return ipf_return_invalid(pkt);
+    }
+
+    const char *tail = dp_packet_tail(pkt);
+    uint8_t pad = dp_packet_l2_pad_size(pkt);
+    size_t l3_size = tail - (char *)l3 - pad;
+    size_t l3_hdr_size = sizeof *l3;
+
+    if (OVS_UNLIKELY(l3_size < l3_hdr_size)) {
+        return ipf_return_invalid(pkt);
+    }
+
+    uint8_t nw_frag = 0;
+    uint8_t nw_proto = l3->ip6_nxt;
+    const void *data = l3 + 1;
+    size_t datasize = l3_size - l3_hdr_size;
+    const struct ovs_16aligned_ip6_frag *frag_hdr = NULL;
+    if (!parse_ipv6_ext_hdrs(&data, &datasize, &nw_proto, &nw_frag,
+                             &frag_hdr) || !nw_frag || !frag_hdr) {
+        return false;
+    }
+
+    int pl = ntohs(l3->ip6_plen);
+    if (OVS_UNLIKELY(pl + l3_hdr_size != l3_size)) {
+        return ipf_return_invalid(pkt);
+    }
+
+    ovs_be16 ip6f_offlg = frag_hdr->ip6f_offlg;
+    if (OVS_UNLIKELY(!ipf_is_v6_frag(ip6f_offlg))) {
+        return false;
+    }
+
+    uint32_t min_v6_frag_size_;
+    atomic_read_relaxed(&min_v6_frag_size, &min_v6_frag_size_);
+    bool lf = ipf_is_last_v6_frag(ip6f_offlg);
+
+    if (OVS_UNLIKELY(!lf && dp_packet_size(pkt) < min_v6_frag_size_)) {
+        ipf_count(true, IPF_COUNTER_NFRAGS_TOO_SMALL);
+        return ipf_return_invalid(pkt);
+    }
+
+    return true;
+}
+
+static void
+ipf_v6_key_extract(struct dp_packet *pkt, ovs_be16 dl_type, uint16_t zone,
+                   struct ipf_list_key *key, uint16_t *start_data_byte,
+                   uint16_t *end_data_byte, bool *ff, bool *lf)
+{
+    const struct  ovs_16aligned_ip6_hdr *l3 = dp_packet_l3(pkt);
+    const char *l4 = dp_packet_l4(pkt);
+    const char *tail = dp_packet_tail(pkt);
+    uint8_t pad = dp_packet_l2_pad_size(pkt);
+    size_t l3_size = tail - (char *)l3 - pad;
+    size_t l4_size = tail - (char *)l4 - pad;
+    size_t l3_hdr_size = sizeof *l3;
+    uint8_t nw_frag = 0;
+    uint8_t nw_proto = l3->ip6_nxt;
+    const void *data = l3 + 1;
+    size_t datasize = l3_size - l3_hdr_size;
+
+    const struct ovs_16aligned_ip6_frag *frag_hdr = NULL;
+    parse_ipv6_ext_hdrs(&data, &datasize, &nw_proto, &nw_frag, &frag_hdr);
+    ovs_assert(nw_frag && frag_hdr);
+    ovs_be16 ip6f_offlg = frag_hdr->ip6f_offlg;
+    *start_data_byte = ntohs(ip6f_offlg & IP6F_OFF_MASK) +
+        sizeof (struct ovs_16aligned_ip6_frag);
+    *end_data_byte = *start_data_byte + l4_size - 1;
+    *ff = ipf_is_first_v6_frag(ip6f_offlg);
+    *lf = ipf_is_last_v6_frag(ip6f_offlg);
+    memset(key, 0, sizeof *key);
+    key->ip_id = get_16aligned_be32(&frag_hdr->ip6f_ident);
+    key->dl_type = dl_type;
+    key->src_addr.ipv6 = l3->ip6_src;
+    /* We are not supporting parsing of the routing header to use as the
+     * dst address part of the key. */
+    key->dst_addr.ipv6 = l3->ip6_dst;
+    key->nw_proto = 0;   /* Not used for key for V6. */
+    key->zone = zone;
+    key->recirc_id = pkt->md.recirc_id;
+}
+
+static int
+ipf_list_key_cmp(const struct ipf_list_key *key1,
+                 const struct ipf_list_key *key2)
+    OVS_REQUIRES(ipf_lock)
+{
+    if (!memcmp(&key1->src_addr, &key2->src_addr, sizeof key1->src_addr) &&
+        !memcmp(&key1->dst_addr, &key2->dst_addr, sizeof key1->dst_addr) &&
+        (key1->dl_type == key2->dl_type) &&
+        (key1->ip_id == key2->ip_id) &&
+        (key1->zone == key2->zone) &&
+        (key1->nw_proto == key2->nw_proto) &&
+        (key1->recirc_id == key2->recirc_id)) {
+        return 0;
+    }
+    return 1;
+}
+
+static struct ipf_list *
+ipf_list_key_lookup(const struct ipf_list_key *key,
+                    uint32_t hash)
+    OVS_REQUIRES(ipf_lock)
+{
+    struct ipf_list *ipf_list;
+    HMAP_FOR_EACH_WITH_HASH (ipf_list, node, hash, &frag_lists) {
+        if (!ipf_list_key_cmp(&ipf_list->key, key)) {
+            return ipf_list;
+        }
+    }
+    return NULL;
+}
+
+static bool
+ipf_is_frag_duped(const struct ipf_frag *frag_list, int last_inuse_idx,
+                  size_t start_data_byte, size_t end_data_byte)
+    OVS_REQUIRES(ipf_lock)
+{
+    for (int i = 0; i <= last_inuse_idx; i++) {
+        if (((start_data_byte >= frag_list[i].start_data_byte) &&
+            (start_data_byte <= frag_list[i].end_data_byte)) ||
+            ((end_data_byte >= frag_list[i].start_data_byte) &&
+             (end_data_byte <= frag_list[i].end_data_byte))) {
+            return true;
+        }
+    }
+    return false;
+}
+
+static bool
+ipf_process_frag(struct ipf_list *ipf_list, struct dp_packet *pkt,
+                 uint16_t start_data_byte, uint16_t end_data_byte,
+                 bool ff, bool lf, bool v6)
+    OVS_REQUIRES(ipf_lock)
+{
+    bool duped_frag = ipf_is_frag_duped(ipf_list->frag_list,
+        ipf_list->last_inuse_idx, start_data_byte, end_data_byte);
+    int last_inuse_idx = ipf_list->last_inuse_idx;
+
+    if (!duped_frag) {
+        if (last_inuse_idx < ipf_list->size - 1) {
+            /* In the case of dpdk, it would be unfortunate if we had
+             * to create a clone fragment outside the dpdk mp due to the
+             * mempool size being too limited. We will otherwise need to
+             * recommend not setting the mempool number of buffers too low
+             * and also clamp the number of fragments. */
+            ipf_list->frag_list[last_inuse_idx + 1].pkt = pkt;
+            ipf_list->frag_list[last_inuse_idx + 1].start_data_byte =
+                start_data_byte;
+            ipf_list->frag_list[last_inuse_idx + 1].end_data_byte =
+                end_data_byte;
+            ipf_list->last_inuse_idx++;
+            atomic_count_inc(&nfrag);
+            ipf_count(v6, IPF_COUNTER_NFRAGS_ACCEPTED);
+            ipf_list_state_transition(ipf_list, ff, lf, v6);
+        } else {
+            OVS_NOT_REACHED();
+        }
+    } else {
+        ipf_count(v6, IPF_COUNTER_NFRAGS_OVERLAP);
+        pkt->md.ct_state = CS_INVALID;
+        return false;
+    }
+    return true;
+}
+
+static bool
+ipf_handle_frag(struct dp_packet *pkt, ovs_be16 dl_type, uint16_t zone,
+                long long now, uint32_t hash_basis)
+    OVS_REQUIRES(ipf_lock)
+{
+    struct ipf_list_key key;
+    /* Initialize 4 variables for some versions of GCC. */
+    uint16_t start_data_byte = 0;
+    uint16_t end_data_byte = 0;
+    bool ff = false;
+    bool lf = false;
+    bool v6 = dl_type == htons(ETH_TYPE_IPV6);
+
+    if (v6 && ipf_get_v6_enabled()) {
+        ipf_v6_key_extract(pkt, dl_type, zone, &key, &start_data_byte,
+                           &end_data_byte, &ff, &lf);
+    } else if (!v6 && ipf_get_v4_enabled()) {
+        ipf_v4_key_extract(pkt, dl_type, zone, &key, &start_data_byte,
+                           &end_data_byte, &ff, &lf);
+    } else {
+        OVS_NOT_REACHED();
+    }
+
+    unsigned int nfrag_max_;
+    atomic_read_relaxed(&nfrag_max, &nfrag_max_);
+    if (atomic_count_get(&nfrag) >= nfrag_max_) {
+        return false;
+    }
+
+    uint32_t hash = ipf_list_key_hash(&key, hash_basis);
+    struct ipf_list *ipf_list = ipf_list_key_lookup(&key, hash);
+    enum {
+        IPF_FRAG_LIST_MIN_INCREMENT = 4,
+        IPF_IPV6_MAX_FRAG_LIST_SIZE = 65535,
+    };
+
+    int max_frag_list_size;
+    if (v6) {
+        /* Because the calculation with extension headers is variable,
+         * we don't calculate a hard maximum fragment list size upfront.  The
+         * fragment list size is practically limited by the code, however. */
+        max_frag_list_size = IPF_IPV6_MAX_FRAG_LIST_SIZE;
+    } else {
+        max_frag_list_size = max_v4_frag_list_size;
+    }
+
+    if (!ipf_list) {
+        ipf_list = xzalloc(sizeof *ipf_list);
+        ipf_list->key = key;
+        ipf_list->last_inuse_idx = IPF_INVALID_IDX;
+        ipf_list->last_sent_idx = IPF_INVALID_IDX;
+        ipf_list->size =
+            MIN(max_frag_list_size, IPF_FRAG_LIST_MIN_INCREMENT);
+        ipf_list->frag_list =
+            xzalloc(ipf_list->size * sizeof *ipf_list->frag_list);
+        hmap_insert(&frag_lists, &ipf_list->node, hash);
+        ipf_expiry_list_add(ipf_list, now);
+    } else if (ipf_list->state == IPF_LIST_STATE_REASS_FAIL) {
+        /* Bail out as early as possible. */
+        return false;
+    } else if (ipf_list->last_inuse_idx + 1 >= ipf_list->size) {
+        int increment = MIN(IPF_FRAG_LIST_MIN_INCREMENT,
+                            max_frag_list_size - ipf_list->size);
+        /* Enforce limit. */
+        if (increment > 0) {
+            ipf_list->frag_list =
+                xrealloc(ipf_list->frag_list, (ipf_list->size + increment) *
+                  sizeof *ipf_list->frag_list);
+            ipf_list->size += increment;
+        } else {
+            return false;
+        }
+    }
+
+    return ipf_process_frag(ipf_list, pkt, start_data_byte, end_data_byte, ff,
+                            lf, v6);
+}
+
+static void
+ipf_extract_frags_from_batch(struct dp_packet_batch *pb, ovs_be16 dl_type,
+                             uint16_t zone, long long now, uint32_t hash_basis)
+{
+    const size_t pb_cnt = dp_packet_batch_size(pb);
+    int pb_idx; /* Index in a packet batch. */
+    struct dp_packet *pkt;
+
+    DP_PACKET_BATCH_REFILL_FOR_EACH (pb_idx, pb_cnt, pkt, pb) {
+
+        if (OVS_UNLIKELY((dl_type == htons(ETH_TYPE_IP) &&
+                          ipf_is_valid_v4_frag(pkt)) ||
+                         (dl_type == htons(ETH_TYPE_IPV6) &&
+                          ipf_is_valid_v6_frag(pkt)))) {
+
+            ipf_lock_lock(&ipf_lock);
+            if (!ipf_handle_frag(pkt, dl_type, zone, now, hash_basis)) {
+                dp_packet_batch_refill(pb, pkt, pb_idx);
+            }
+            ipf_lock_unlock(&ipf_lock);
+        } else {
+            dp_packet_batch_refill(pb, pkt, pb_idx);
+        }
+
+    }
+}
+
+/* In case of DPDK, a memory source check is done, as DPDK memory pool
+ * management has trouble dealing with multiple source types.  The
+ * check_source paramater is used to indicate when this check is needed. */
+static bool
+ipf_dp_packet_batch_add(struct dp_packet_batch *pb , struct dp_packet *pkt,
+                        bool check_source OVS_UNUSED)
+    OVS_REQUIRES(ipf_lock)
+{
+#ifdef DPDK_NETDEV
+    if ((pb->count >= NETDEV_MAX_BURST) ||
+        /* DPDK cannot handle multiple sources in a batch. */
+        (check_source && pb->count && pb->packets[0]->source != pkt->source)) {
+#else
+    if (pb->count >= NETDEV_MAX_BURST) {
+#endif
+        return false;
+    }
+
+    dp_packet_batch_add(pb, pkt);
+    return true;
+}
+
+/* This would be used in a rare case where a list cannot be sent. The only
+ * reason known right now is a mempool source check, which exists due to DPDK
+ * support, where packets are no longer being received on any port with a
+ * source matching the fragment.
+ * Returns true if the list was purged. */
+static bool
+ipf_purge_list_check(struct ipf_list *ipf_list, long long now)
+    OVS_REQUIRES(ipf_lock)
+{
+    enum {
+        /* 10 minutes. */
+        IPF_FRAG_LIST_TIMEOUT_PURGE = 600000,
+    };
+
+    if (now < ipf_list->expiration + IPF_FRAG_LIST_TIMEOUT_PURGE) {
+        return false;
+    }
+
+    struct dp_packet *pkt;
+    while (ipf_list->last_sent_idx < ipf_list->last_inuse_idx) {
+        pkt = ipf_list->frag_list[ipf_list->last_sent_idx + 1].pkt;
+        dp_packet_delete(pkt);
+        atomic_count_dec(&nfrag);
+        ipf_list->last_sent_idx++;
+    }
+
+    static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 5);
+    VLOG_WARN_RL(&rl, "Fragments dropped due to stuck fragment list purge.");
+    COVERAGE_INC(ipf_stuck_frag_list_purged);
+    return true;
+}
+
+static bool
+ipf_send_frags_in_list(struct ipf_list *ipf_list, struct dp_packet_batch *pb,
+                       enum ipf_list_type list_type, bool v6, long long now)
+    OVS_REQUIRES(ipf_lock)
+{
+    if (ipf_purge_list_check(ipf_list, now)) {
+        return true;
+    }
+
+    struct dp_packet *pkt;
+    while (ipf_list->last_sent_idx < ipf_list->last_inuse_idx) {
+        pkt = ipf_list->frag_list[ipf_list->last_sent_idx + 1].pkt;
+        if (ipf_dp_packet_batch_add(pb, pkt, true)) {
+
+            ipf_list->last_sent_idx++;
+            atomic_count_dec(&nfrag);
+
+            if (list_type == IPF_FRAG_COMPLETED_LIST) {
+                ipf_count(v6, IPF_COUNTER_NFRAGS_COMPL_SENT);
+            } else {
+                ipf_count(v6, IPF_COUNTER_NFRAGS_EXPD_SENT);
+                pkt->md.ct_state = CS_INVALID;
+            }
+
+            if (ipf_list->last_sent_idx == ipf_list->last_inuse_idx) {
+                return true;
+            }
+        } else {
+            return false;
+        }
+    }
+    OVS_NOT_REACHED();
+}
+
+static void
+ipf_send_completed_frags(struct dp_packet_batch *pb, long long now, bool v6)
+{
+    if (ovs_list_is_empty(&frag_complete_list)) {
+        return;
+    }
+
+    ipf_lock_lock(&ipf_lock);
+    struct ipf_list *ipf_list, *next;
+
+    LIST_FOR_EACH_SAFE (ipf_list, next, list_node, &frag_complete_list) {
+        if (ipf_send_frags_in_list(ipf_list, pb, IPF_FRAG_COMPLETED_LIST,
+                                   v6, now)) {
+            ipf_completed_list_clean(ipf_list);
+        } else {
+            break;
+        }
+    }
+    ipf_lock_unlock(&ipf_lock);
+}
+
+static void
+ipf_send_expired_frags(struct dp_packet_batch *pb, long long now, bool v6)
+{
+    enum {
+        /* Very conservative, due to DOS probability. */
+        IPF_FRAG_LIST_MAX_EXPIRED = 1,
+    };
+
+
+    if (ovs_list_is_empty(&frag_exp_list)) {
+        return;
+    }
+
+    ipf_lock_lock(&ipf_lock);
+    struct ipf_list *ipf_list, *next;
+    size_t lists_removed = 0;
+
+    LIST_FOR_EACH_SAFE (ipf_list, next, list_node, &frag_exp_list) {
+        if (!(now > ipf_list->expiration) ||
+            lists_removed >= IPF_FRAG_LIST_MAX_EXPIRED) {
+            break;
+        }
+
+        if (ipf_send_frags_in_list(ipf_list, pb, IPF_FRAG_EXPIRY_LIST, v6,
+                                   now)) {
+            ipf_expiry_list_clean(ipf_list);
+            lists_removed++;
+        } else {
+            break;
+        }
+    }
+    ipf_lock_unlock(&ipf_lock);
+}
+
+static void
+ipf_execute_reass_pkts(struct dp_packet_batch *pb)
+{
+    if (ovs_list_is_empty(&reassembled_pkt_list)) {
+        return;
+    }
+
+    ipf_lock_lock(&ipf_lock);
+    struct reassembled_pkt *rp, *next;
+
+    LIST_FOR_EACH_SAFE (rp, next, rp_list_node, &reassembled_pkt_list) {
+        if (!rp->list->reass_execute_ctx &&
+            ipf_dp_packet_batch_add(pb, rp->pkt, false)) {
+            rp->list->reass_execute_ctx = rp->pkt;
+        }
+    }
+    ipf_lock_unlock(&ipf_lock);
+}
+
+static void
+ipf_post_execute_reass_pkts(struct dp_packet_batch *pb, bool v6)
+{
+    if (ovs_list_is_empty(&reassembled_pkt_list)) {
+        return;
+    }
+
+    ipf_lock_lock(&ipf_lock);
+    struct reassembled_pkt *rp, *next;
+
+    LIST_FOR_EACH_SAFE (rp, next, rp_list_node, &reassembled_pkt_list) {
+        const size_t pb_cnt = dp_packet_batch_size(pb);
+        int pb_idx;
+        struct dp_packet *pkt;
+        /* Inner batch loop is constant time since batch size is <=
+         * NETDEV_MAX_BURST. */
+        DP_PACKET_BATCH_REFILL_FOR_EACH (pb_idx, pb_cnt, pkt, pb) {
+            if (pkt == rp->list->reass_execute_ctx) {
+                for (int i = 0; i <= rp->list->last_inuse_idx; i++) {
+                    rp->list->frag_list[i].pkt->md.ct_label = pkt->md.ct_label;
+                    rp->list->frag_list[i].pkt->md.ct_mark = pkt->md.ct_mark;
+                    rp->list->frag_list[i].pkt->md.ct_state = pkt->md.ct_state;
+                    rp->list->frag_list[i].pkt->md.ct_zone = pkt->md.ct_zone;
+                    rp->list->frag_list[i].pkt->md.ct_orig_tuple_ipv6 =
+                        pkt->md.ct_orig_tuple_ipv6;
+                    if (pkt->md.ct_orig_tuple_ipv6) {
+                        rp->list->frag_list[i].pkt->md.ct_orig_tuple.ipv6 =
+                            pkt->md.ct_orig_tuple.ipv6;
+                    } else {
+                        rp->list->frag_list[i].pkt->md.ct_orig_tuple.ipv4  =
+                            pkt->md.ct_orig_tuple.ipv4;
+                    }
+                }
+
+                const char *tail_frag =
+                    dp_packet_tail(rp->list->frag_list[0].pkt);
+                uint8_t pad_frag =
+                    dp_packet_l2_pad_size(rp->list->frag_list[0].pkt);
+
+                void *l4_frag = dp_packet_l4(rp->list->frag_list[0].pkt);
+                void *l4_reass = dp_packet_l4(pkt);
+                memcpy(l4_frag, l4_reass,
+                       tail_frag - (char *) l4_frag - pad_frag);
+
+                if (v6) {
+                    struct  ovs_16aligned_ip6_hdr *l3_frag =
+                        dp_packet_l3(rp->list->frag_list[0].pkt);
+                    struct  ovs_16aligned_ip6_hdr *l3_reass =
+                        dp_packet_l3(pkt);
+                    l3_frag->ip6_src = l3_reass->ip6_src;
+                    l3_frag->ip6_dst = l3_reass->ip6_dst;
+                } else {
+                    struct ip_header *l3_frag =
+                        dp_packet_l3(rp->list->frag_list[0].pkt);
+                    struct ip_header *l3_reass = dp_packet_l3(pkt);
+                    ovs_be32 reass_ip = get_16aligned_be32(&l3_reass->ip_src);
+                    ovs_be32 frag_ip = get_16aligned_be32(&l3_frag->ip_src);
+                    l3_frag->ip_csum = recalc_csum32(l3_frag->ip_csum,
+                                                     frag_ip, reass_ip);
+                    l3_frag->ip_src = l3_reass->ip_src;
+
+                    reass_ip = get_16aligned_be32(&l3_reass->ip_dst);
+                    frag_ip = get_16aligned_be32(&l3_frag->ip_dst);
+                    l3_frag->ip_csum = recalc_csum32(l3_frag->ip_csum,
+                                                     frag_ip, reass_ip);
+                    l3_frag->ip_dst = l3_reass->ip_dst;
+                }
+
+                ipf_completed_list_add(rp->list);
+                ipf_reassembled_list_remove(rp);
+                dp_packet_delete(rp->pkt);
+                free(rp);
+            } else {
+                dp_packet_batch_refill(pb, pkt, pb_idx);
+            }
+        }
+    }
+    ipf_lock_unlock(&ipf_lock);
+}
+
+/* Extracts any fragments from the batch and reassembles them when a
+ * complete packet is received.  Completed packets are attempted to
+ * be added to the batch to be sent thru. conntrack. */
+void
+ipf_preprocess_conntrack(struct dp_packet_batch *pb, long long now,
+                         ovs_be16 dl_type, uint16_t zone, uint32_t hash_basis)
+{
+    if (ipf_get_enabled()) {
+        ipf_extract_frags_from_batch(pb, dl_type, zone, now, hash_basis);
+    }
+
+    if (ipf_get_enabled() || atomic_count_get(&nfrag)) {
+        ipf_execute_reass_pkts(pb);
+    }
+}
+
+/* Updates fragments based on the processing of the reassembled packet sent
+ * thru. conntrack and adds these fragments to any batches seen.  Expired
+ * fragments are marked as invalid and also added to the batches seen
+ * with low priority.  Reassembled packets are freed. */
+void
+ipf_postprocess_conntrack(struct dp_packet_batch *pb, long long now,
+                          ovs_be16 dl_type)
+{
+    if (ipf_get_enabled() || atomic_count_get(&nfrag)) {
+        bool v6 = dl_type == htons(ETH_TYPE_IPV6);
+        ipf_post_execute_reass_pkts(pb, v6);
+        ipf_send_completed_frags(pb, now, v6);
+        ipf_send_expired_frags(pb, now, v6);
+    }
+}
+
+void
+ipf_init(void)
+{
+    ipf_lock_init(&ipf_lock);
+    ipf_lock_lock(&ipf_lock);
+    hmap_init(&frag_lists);
+    ovs_list_init(&frag_exp_list);
+    ovs_list_init(&frag_complete_list);
+    ovs_list_init(&reassembled_pkt_list);
+    atomic_init(&min_v4_frag_size, IPF_V4_FRAG_SIZE_MIN_DEF);
+    atomic_init(&min_v6_frag_size, IPF_V6_FRAG_SIZE_MIN_DEF);
+    max_v4_frag_list_size = DIV_ROUND_UP(
+        IPV4_PACKET_MAX_SIZE - IPV4_PACKET_MAX_HDR_SIZE,
+        min_v4_frag_size - IPV4_PACKET_MAX_HDR_SIZE);
+    ipf_lock_unlock(&ipf_lock);
+    atomic_count_init(&nfrag, 0);
+    atomic_count_init(&n4frag_accepted, 0);
+    atomic_count_init(&n4frag_completed_sent, 0);
+    atomic_count_init(&n4frag_expired_sent, 0);
+    atomic_count_init(&n4frag_too_small, 0);
+    atomic_count_init(&n4frag_overlap, 0);
+    atomic_count_init(&n6frag_accepted, 0);
+    atomic_count_init(&n6frag_completed_sent, 0);
+    atomic_count_init(&n6frag_expired_sent, 0);
+    atomic_count_init(&n6frag_too_small, 0);
+    atomic_count_init(&n6frag_overlap, 0);
+    atomic_init(&nfrag_max, IPF_MAX_FRAGS_DEFAULT);
+    atomic_init(&ifp_v4_enabled, true);
+    atomic_init(&ifp_v6_enabled, true);
+}
+
+void
+ipf_destroy(void)
+{
+    ipf_lock_lock(&ipf_lock);
+
+    struct ipf_list *ipf_list;
+    HMAP_FOR_EACH_POP (ipf_list, node, &frag_lists) {
+        struct dp_packet *pkt;
+        while (ipf_list->last_sent_idx < ipf_list->last_inuse_idx) {
+            pkt = ipf_list->frag_list[ipf_list->last_sent_idx + 1].pkt;
+            dp_packet_delete(pkt);
+            atomic_count_dec(&nfrag);
+            ipf_list->last_sent_idx++;
+        }
+        free(ipf_list->frag_list);
+        free(ipf_list);
+    }
+
+    if (atomic_count_get(&nfrag)) {
+        VLOG_WARN("ipf destroy with non-zero fragment count. ");
+    }
+
+    struct reassembled_pkt * rp;
+    LIST_FOR_EACH_POP (rp, rp_list_node, &reassembled_pkt_list) {
+        dp_packet_delete(rp->pkt);
+        free(rp);
+    }
+
+    hmap_destroy(&frag_lists);
+    ovs_list_poison(&frag_exp_list);
+    ovs_list_poison(&frag_complete_list);
+    ovs_list_poison(&reassembled_pkt_list);
+    ipf_lock_unlock(&ipf_lock);
+    ipf_lock_destroy(&ipf_lock);
+}
diff --git a/lib/ipf.h b/lib/ipf.h
new file mode 100644
index 0000000..212d1b3
--- /dev/null
+++ b/lib/ipf.h
@@ -0,0 +1,60 @@ 
+/*
+ * Copyright (c) 2018 Nicira, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef IPF_H
+#define IPF_H 1
+
+#include "dp-packet.h"
+#include "openvswitch/types.h"
+
+struct ipf_status {
+   bool ifp_v4_enabled;
+   unsigned int min_v4_frag_size;
+   unsigned int nfrag_max;
+   unsigned int nfrag;
+   unsigned int n4frag_accepted;
+   unsigned int n4frag_completed_sent;
+   unsigned int n4frag_expired_sent;
+   unsigned int n4frag_too_small;
+   unsigned int n4frag_overlap;
+   bool ifp_v6_enabled;
+   unsigned int min_v6_frag_size;
+   unsigned int n6frag_accepted;
+   unsigned int n6frag_completed_sent;
+   unsigned int n6frag_expired_sent;
+   unsigned int n6frag_too_small;
+   unsigned int n6frag_overlap;
+};
+
+/* Collects and reassembles fragments which are to be sent through
+ * conntrack, if fragment processing is enabled or fragments are
+ * in flight. */
+void ipf_preprocess_conntrack(struct dp_packet_batch *pb, long long now,
+                              ovs_be16 dl_type, uint16_t zone,
+                              uint32_t hash_basis);
+
+/* Updates the state of fragments associated with reassembled packets and
+ * sends out fragments that are either associated with completed
+ * packets or expired, if fragment processing is enabled or fragments are
+ * in flight. */
+void ipf_postprocess_conntrack(struct dp_packet_batch *pb, long long now,
+                               ovs_be16 dl_type);
+
+void ipf_init(void);
+
+void ipf_destroy(void);
+
+#endif /* ipf.h */
diff --git a/tests/system-kmod-macros.at b/tests/system-kmod-macros.at
index 07de0db..3ea5b87 100644
--- a/tests/system-kmod-macros.at
+++ b/tests/system-kmod-macros.at
@@ -77,12 +77,6 @@  m4_define([CHECK_CONNTRACK],
 #
 m4_define([CHECK_CONNTRACK_ALG])
 
-# CHECK_CONNTRACK_FRAG()
-#
-# Perform requirements checks for running conntrack fragmentations tests.
-# The kernel always supports fragmentation, so no check is needed.
-m4_define([CHECK_CONNTRACK_FRAG])
-
 # CHECK_CONNTRACK_LOCAL_STACK()
 #
 # Perform requirements checks for running conntrack tests with local stack.
@@ -91,6 +85,10 @@  m4_define([CHECK_CONNTRACK_FRAG])
 # needed.
 m4_define([CHECK_CONNTRACK_LOCAL_STACK])
 
+# CHECK_CONNTRACK_SMALL_FRAG()
+#
+m4_define([CHECK_CONNTRACK_SMALL_FRAG])
+
 # CHECK_CONNTRACK_FRAG_OVERLAP()
 #
 # The kernel does not support overlapping fragments checking.
diff --git a/tests/system-traffic.at b/tests/system-traffic.at
index 43a104d..556a6a0 100644
--- a/tests/system-traffic.at
+++ b/tests/system-traffic.at
@@ -1905,7 +1905,6 @@  AT_CLEANUP
 
 AT_SETUP([conntrack - IPv4 fragmentation])
 CHECK_CONNTRACK()
-CHECK_CONNTRACK_FRAG()
 OVS_TRAFFIC_VSWITCHD_START()
 
 ADD_NAMESPACES(at_ns0, at_ns1)
@@ -1939,7 +1938,6 @@  AT_CLEANUP
 
 AT_SETUP([conntrack - IPv4 fragmentation expiry])
 CHECK_CONNTRACK()
-CHECK_CONNTRACK_FRAG()
 OVS_TRAFFIC_VSWITCHD_START()
 
 ADD_NAMESPACES(at_ns0, at_ns1)
@@ -1970,7 +1968,6 @@  AT_CLEANUP
 
 AT_SETUP([conntrack - IPv4 fragmentation + vlan])
 CHECK_CONNTRACK()
-CHECK_CONNTRACK_FRAG()
 OVS_TRAFFIC_VSWITCHD_START()
 
 ADD_NAMESPACES(at_ns0, at_ns1)
@@ -2006,7 +2003,6 @@  AT_CLEANUP
 
 AT_SETUP([conntrack - IPv4 fragmentation + cvlan])
 CHECK_CONNTRACK()
-CHECK_CONNTRACK_FRAG()
 OVS_TRAFFIC_VSWITCHD_START([set Open_vSwitch . other_config:vlan-limit=0])
 OVS_CHECK_8021AD()
 
@@ -2081,7 +2077,7 @@  AT_CLEANUP
 dnl Uses same first fragment as above 'incomplete reassembled packet' test.
 AT_SETUP([conntrack - IPv4 fragmentation with fragments specified])
 CHECK_CONNTRACK()
-CHECK_CONNTRACK_FRAG()
+CHECK_CONNTRACK_SMALL_FRAG()
 OVS_TRAFFIC_VSWITCHD_START()
 
 ADD_NAMESPACES(at_ns0, at_ns1)
@@ -2105,7 +2101,7 @@  AT_CLEANUP
 
 AT_SETUP([conntrack - IPv4 fragmentation out of order])
 CHECK_CONNTRACK()
-CHECK_CONNTRACK_FRAG()
+CHECK_CONNTRACK_SMALL_FRAG()
 OVS_TRAFFIC_VSWITCHD_START()
 
 ADD_NAMESPACES(at_ns0, at_ns1)
@@ -2129,7 +2125,7 @@  AT_CLEANUP
 
 AT_SETUP([conntrack - IPv4 fragmentation overlapping fragments by 1 octet])
 CHECK_CONNTRACK()
-CHECK_CONNTRACK_FRAG()
+CHECK_CONNTRACK_SMALL_FRAG()
 CHECK_CONNTRACK_FRAG_OVERLAP()
 OVS_TRAFFIC_VSWITCHD_START()
 
@@ -2153,7 +2149,7 @@  AT_CLEANUP
 
 AT_SETUP([conntrack - IPv4 fragmentation overlapping fragments by 1 octet out of order])
 CHECK_CONNTRACK()
-CHECK_CONNTRACK_FRAG()
+CHECK_CONNTRACK_SMALL_FRAG()
 CHECK_CONNTRACK_FRAG_OVERLAP()
 OVS_TRAFFIC_VSWITCHD_START()
 
@@ -2177,7 +2173,6 @@  AT_CLEANUP
 
 AT_SETUP([conntrack - IPv6 fragmentation])
 CHECK_CONNTRACK()
-CHECK_CONNTRACK_FRAG()
 OVS_TRAFFIC_VSWITCHD_START()
 
 ADD_NAMESPACES(at_ns0, at_ns1)
@@ -2217,7 +2212,6 @@  AT_CLEANUP
 
 AT_SETUP([conntrack - IPv6 fragmentation expiry])
 CHECK_CONNTRACK()
-CHECK_CONNTRACK_FRAG()
 OVS_TRAFFIC_VSWITCHD_START()
 
 ADD_NAMESPACES(at_ns0, at_ns1)
@@ -2258,7 +2252,6 @@  AT_CLEANUP
 
 AT_SETUP([conntrack - IPv6 fragmentation + vlan])
 CHECK_CONNTRACK()
-CHECK_CONNTRACK_FRAG()
 OVS_TRAFFIC_VSWITCHD_START()
 
 ADD_NAMESPACES(at_ns0, at_ns1)
@@ -2301,7 +2294,6 @@  AT_CLEANUP
 
 AT_SETUP([conntrack - IPv6 fragmentation + cvlan])
 CHECK_CONNTRACK()
-CHECK_CONNTRACK_FRAG()
 OVS_TRAFFIC_VSWITCHD_START([set Open_vSwitch . other_config:vlan-limit=0])
 OVS_CHECK_8021AD()
 
@@ -2376,7 +2368,7 @@  AT_CLEANUP
 
 AT_SETUP([conntrack - IPv6 fragmentation with fragments specified])
 CHECK_CONNTRACK()
-CHECK_CONNTRACK_FRAG()
+CHECK_CONNTRACK_SMALL_FRAG()
 OVS_TRAFFIC_VSWITCHD_START()
 
 ADD_NAMESPACES(at_ns0, at_ns1)
@@ -2400,7 +2392,7 @@  AT_CLEANUP
 
 AT_SETUP([conntrack - IPv6 fragmentation out of order])
 CHECK_CONNTRACK()
-CHECK_CONNTRACK_FRAG()
+CHECK_CONNTRACK_SMALL_FRAG()
 OVS_TRAFFIC_VSWITCHD_START()
 
 ADD_NAMESPACES(at_ns0, at_ns1)
@@ -2424,7 +2416,7 @@  AT_CLEANUP
 
 AT_SETUP([conntrack - IPv6 fragmentation, multiple extension headers])
 CHECK_CONNTRACK()
-CHECK_CONNTRACK_FRAG()
+CHECK_CONNTRACK_SMALL_FRAG()
 CHECK_CONNTRACK_FRAG_IPV6_MULT_EXTEN()
 OVS_TRAFFIC_VSWITCHD_START()
 
@@ -2450,7 +2442,7 @@  AT_CLEANUP
 
 AT_SETUP([conntrack - IPv6 fragmentation, multiple extension headers + out of order])
 CHECK_CONNTRACK()
-CHECK_CONNTRACK_FRAG()
+CHECK_CONNTRACK_SMALL_FRAG()
 CHECK_CONNTRACK_FRAG_IPV6_MULT_EXTEN()
 OVS_TRAFFIC_VSWITCHD_START()
 
@@ -2476,7 +2468,7 @@  AT_CLEANUP
 
 AT_SETUP([conntrack - IPv6 fragmentation, multiple extension headers 2])
 CHECK_CONNTRACK()
-CHECK_CONNTRACK_FRAG()
+CHECK_CONNTRACK_SMALL_FRAG()
 CHECK_CONNTRACK_FRAG_IPV6_MULT_EXTEN()
 OVS_TRAFFIC_VSWITCHD_START()
 
@@ -2502,7 +2494,7 @@  AT_CLEANUP
 
 AT_SETUP([conntrack - IPv6 fragmentation, multiple extension headers 2 + out of order])
 CHECK_CONNTRACK()
-CHECK_CONNTRACK_FRAG()
+CHECK_CONNTRACK_SMALL_FRAG()
 CHECK_CONNTRACK_FRAG_IPV6_MULT_EXTEN()
 OVS_TRAFFIC_VSWITCHD_START()
 
@@ -2529,7 +2521,6 @@  AT_CLEANUP
 AT_SETUP([conntrack - Fragmentation over vxlan])
 OVS_CHECK_VXLAN()
 CHECK_CONNTRACK()
-CHECK_CONNTRACK_FRAG()
 CHECK_CONNTRACK_LOCAL_STACK()
 
 OVS_TRAFFIC_VSWITCHD_START()
@@ -2582,7 +2573,6 @@  AT_CLEANUP
 AT_SETUP([conntrack - IPv6 Fragmentation over vxlan])
 OVS_CHECK_VXLAN()
 CHECK_CONNTRACK()
-CHECK_CONNTRACK_FRAG()
 CHECK_CONNTRACK_LOCAL_STACK()
 
 OVS_TRAFFIC_VSWITCHD_START()
diff --git a/tests/system-userspace-macros.at b/tests/system-userspace-macros.at
index 11eac8f..40b7567 100644
--- a/tests/system-userspace-macros.at
+++ b/tests/system-userspace-macros.at
@@ -73,15 +73,6 @@  m4_define([CHECK_CONNTRACK],
 #
 m4_define([CHECK_CONNTRACK_ALG])
 
-# CHECK_CONNTRACK_FRAG()
-#
-# Perform requirements checks for running conntrack fragmentations tests.
-# The userspace doesn't support fragmentation yet, so skip the tests.
-m4_define([CHECK_CONNTRACK_FRAG],
-[
-    AT_SKIP_IF([:])
-])
-
 # CHECK_CONNTRACK_LOCAL_STACK()
 #
 # Perform requirements checks for running conntrack tests with local stack.
@@ -93,21 +84,22 @@  m4_define([CHECK_CONNTRACK_LOCAL_STACK],
     AT_SKIP_IF([:])
 ])
 
-# CHECK_CONNTRACK_FRAG_OVERLAP()
+# CHECK_CONNTRACK_SMALL_FRAG()
 #
-# The userspace datapath does not support fragments yet.
-m4_define([CHECK_CONNTRACK_FRAG_OVERLAP],
+m4_define([CHECK_CONNTRACK_SMALL_FRAG],
 [
     AT_SKIP_IF([:])
 ])
 
+# CHECK_CONNTRACK_FRAG_OVERLAP()
+#
+# The userspace datapath supports fragment overlap checking.
+m4_define([CHECK_CONNTRACK_FRAG_OVERLAP])
+
 # CHECK_CONNTRACK_FRAG_IPV6_MULT_EXTEN()
 #
-# The userspace datapath does not support fragments yet.
-m4_define([CHECK_CONNTRACK_FRAG_IPV6_MULT_EXTEN],
-[
-    AT_SKIP_IF([:])
-])
+# The userspace datapath supports fragments with multiple extension headers.
+m4_define([CHECK_CONNTRACK_FRAG_IPV6_MULT_EXTEN])
 
 # CHECK_CONNTRACK_NAT()
 #