[ovs-dev,v5,06/11] ipf: Add set minimum fragment size command.

diff --git a/NEWS b/NEWS
index d53d95d..e98c990 100644
--- a/NEWS
+++ b/NEWS
@@ -15,6 +15,8 @@  Post-v2.9.0
      * Add v4/v6 fragmentation support for conntrack.
      * New "ovs-appctl dpctl/ipf-set-enabled" command for userspace datapath
        conntrack fragmentation support.
+     * New "ovs-appctl dpctl/ipf-set-minfragment" command for userspace
+       datapath conntrack fragmentation support.
 
 v2.9.0 - xx xxx xxxx
 --------------------
diff --git a/lib/ct-dpif.c b/lib/ct-dpif.c
index 32d55c1..4a93bf6 100644
--- a/lib/ct-dpif.c
+++ b/lib/ct-dpif.c
@@ -172,6 +172,14 @@  ct_dpif_ipf_change_enabled(struct dpif *dpif, bool v6, bool enable)
             : EOPNOTSUPP);
 }
 
+int
+ct_dpif_ipf_set_min_frag(struct dpif *dpif, bool v6, uint32_t min_frag)
+{
+    return (dpif->dpif_class->ipf_set_min_frag
+            ? dpif->dpif_class->ipf_set_min_frag(dpif, v6, min_frag)
+            : EOPNOTSUPP);
+}
+
 void
 ct_dpif_entry_uninit(struct ct_dpif_entry *entry)
 {
diff --git a/lib/ct-dpif.h b/lib/ct-dpif.h
index 3f0bce5..449f958 100644
--- a/lib/ct-dpif.h
+++ b/lib/ct-dpif.h
@@ -201,6 +201,7 @@  int ct_dpif_set_maxconns(struct dpif *dpif, uint32_t maxconns);
 int ct_dpif_get_maxconns(struct dpif *dpif, uint32_t *maxconns);
 int ct_dpif_get_nconns(struct dpif *dpif, uint32_t *nconns);
 int ct_dpif_ipf_change_enabled(struct dpif *, bool, bool);
+int ct_dpif_ipf_set_min_frag(struct dpif *, bool, uint32_t);
 void ct_dpif_entry_uninit(struct ct_dpif_entry *);
 void ct_dpif_format_entry(const struct ct_dpif_entry *, struct ds *,
                           bool verbose, bool print_stats);
diff --git a/lib/dpctl.c b/lib/dpctl.c
index 7d332aa..3464afe 100644
--- a/lib/dpctl.c
+++ b/lib/dpctl.c
@@ -1784,6 +1784,44 @@  dpctl_ct_ipf_change_enabled(int argc, const char *argv[],
     return error;
 }
 
+static int
+dpctl_ct_ipf_set_min_frag(int argc, const char *argv[],
+                          struct dpctl_params *dpctl_p)
+{
+    struct dpif *dpif;
+    int error = dpctl_ct_open_dp(argc, argv, dpctl_p, &dpif, 4);
+    if (!error) {
+        char v4_or_v6[3] = {0};
+        if (ovs_scan(argv[argc - 2], "%2s", v4_or_v6) &&
+            (!strncmp(v4_or_v6, "v4", 2) || !strncmp(v4_or_v6, "v6", 2))) {
+            uint32_t min_fragment;
+            if (ovs_scan(argv[argc - 1], "%"SCNu32, &min_fragment)) {
+                error = ct_dpif_ipf_set_min_frag(
+                            dpif, !strncmp(v4_or_v6, "v6", 2), min_fragment);
+
+                if (!error) {
+                    dpctl_print(dpctl_p,
+                                "setting minimum fragment size successful");
+                } else {
+                    dpctl_error(dpctl_p, error,
+                                "setting minimum fragment size failed");
+                }
+            } else {
+                error = EINVAL;
+                dpctl_error(dpctl_p, error,
+                            "parameter missing for minimum fragment size");
+            }
+        } else {
+            error = EINVAL;
+            dpctl_error(dpctl_p, error,
+                        "parameter missing: v4 for ipv4 or v6 for ipv6");
+        }
+        dpif_close(dpif);
+    }
+
+    return error;
+}
+
 /* Undocumented commands for unit testing. */
 
 static int
@@ -2085,6 +2123,8 @@  static const struct dpctl_command all_commands[] = {
     { "ct-get-nconns", "[dp]", 0, 1, dpctl_ct_get_nconns, DP_RO },
     { "ipf-set-enabled", "[dp] v4_or_v6 enabled", 2, 3,
        dpctl_ct_ipf_change_enabled, DP_RW },
+    { "ipf-set-minfragment", "[dp] v4_or_v6 minfragment", 2, 3,
+       dpctl_ct_ipf_set_min_frag, DP_RW },
     { "help", "", 0, INT_MAX, dpctl_help, DP_RO },
     { "list-commands", "", 0, INT_MAX, dpctl_list_commands, DP_RO },
 
diff --git a/lib/dpctl.man b/lib/dpctl.man
index 491de0b..87067f9 100644
--- a/lib/dpctl.man
+++ b/lib/dpctl.man
@@ -279,3 +279,10 @@  differentiate between first and other fragments.  Although, this would
 logically happen naturally anyways, it is mentioned for clarity.  If there
 is a need to differentiate between first and other fragments, do it after
 conntrack.
+.
+.TP
+\*(DX\fBipf\-set\-minfrag\fR [\fIdp\fR] [\fIv4 or v6\fR] \fBminfrag\fR
+Sets the minimum fragment size supported by the userspace datapath
+connection tracker.  Either v4 or v6 must be specified.  The default v4
+value is 1200 and the clamped minimum is 400.  The default v6 value is
+1280, which is also the clamped minimum.
diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
index d4d0f07..44e511f 100644
--- a/lib/dpif-netdev.c
+++ b/lib/dpif-netdev.c
@@ -5879,6 +5879,13 @@  dpif_netdev_ipf_change_enabled(struct dpif *dpif OVS_UNUSED, bool v6,
     return ipf_change_enabled(v6, enable);
 }
 
+static int
+dpif_netdev_ipf_set_min_frag(struct dpif *dpif OVS_UNUSED, bool v6,
+                             uint32_t min_frag)
+{
+    return ipf_set_min_frag(v6, min_frag);
+}
+
 const struct dpif_class dpif_netdev_class = {
     "netdev",
     dpif_netdev_init,
@@ -5928,6 +5935,7 @@  const struct dpif_class dpif_netdev_class = {
     dpif_netdev_ct_get_maxconns,
     dpif_netdev_ct_get_nconns,
     dpif_netdev_ipf_change_enabled,
+    dpif_netdev_ipf_set_min_frag,
     dpif_netdev_meter_get_features,
     dpif_netdev_meter_set,
     dpif_netdev_meter_get,
diff --git a/lib/dpif-netlink.c b/lib/dpif-netlink.c
index f089617..8366de8 100644
--- a/lib/dpif-netlink.c
+++ b/lib/dpif-netlink.c
@@ -2993,6 +2993,7 @@  const struct dpif_class dpif_netlink_class = {
     NULL,                       /* ct_get_maxconns */
     NULL,                       /* ct_get_nconns */
     NULL,                       /* ipf_change_enabled */
+    NULL,                       /* ipf_set_min_frag */
     dpif_netlink_meter_get_features,
     dpif_netlink_meter_set,
     dpif_netlink_meter_get,
diff --git a/lib/dpif-provider.h b/lib/dpif-provider.h
index 08e0944..aa9c490 100644
--- a/lib/dpif-provider.h
+++ b/lib/dpif-provider.h
@@ -446,6 +446,8 @@  struct dpif_class {
 
     /* IP Fragmentation. */
     int (*ipf_change_enabled)(struct dpif *, bool, bool);
+    /* Set minimum fragment allowed. */
+    int (*ipf_set_min_frag)(struct dpif *, bool, uint32_t);
     /* Meters */
 
     /* Queries 'dpif' for supported meter features.
diff --git a/lib/ipf.c b/lib/ipf.c
index 31d31e9..e78abb4 100644
--- a/lib/ipf.c
+++ b/lib/ipf.c
@@ -1253,3 +1253,26 @@  ipf_change_enabled(bool v6, bool enable)
     }
     return 0;
 }
+
+int
+ipf_set_min_frag(bool v6, uint32_t value)
+{
+    /* If the user specifies an unreasonably large number, fragmentation
+     * will not work well but it will not blow up. */
+    if ((!v6 && value < IPF_V4_FRAG_SIZE_LBOUND) ||
+        (v6 && value < IPF_V6_FRAG_SIZE_LBOUND)) {
+        return 1;
+    }
+
+    ipf_lock_lock(&ipf_lock);
+    if (v6) {
+        atomic_store_relaxed(&min_v6_frag_size, value);
+    } else {
+        atomic_store_relaxed(&min_v4_frag_size, value);
+        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);
+    return 0;
+}
diff --git a/lib/ipf.h b/lib/ipf.h
index 0b45de9..277852d 100644
--- a/lib/ipf.h
+++ b/lib/ipf.h
@@ -63,4 +63,7 @@  ipf_destroy(void);
 int
 ipf_change_enabled(bool v6, bool enable);
 
+int
+ipf_set_min_frag(bool v6, uint32_t value);
+
 #endif /* ipf.h */