[ovs-dev] [patch v9 09/11] ipf: Add set minimum fragment size command.

Darrell Ball dlu998 at gmail.com
Mon Nov 19 19:09:28 UTC 2018


A new command "ovs-appctl dpctl/ipf-set-min-frag" is added
for userspace datapath conntrack v4/v6 fragmentation support.

Signed-off-by: Darrell Ball <dlu998 at gmail.com>
---
 NEWS                |  2 ++
 lib/ct-dpif.c       |  8 ++++++++
 lib/ct-dpif.h       |  1 +
 lib/dpctl.c         | 40 ++++++++++++++++++++++++++++++++++++++++
 lib/dpctl.man       | 11 +++++++++++
 lib/dpif-netdev.c   |  8 ++++++++
 lib/dpif-netlink.c  |  1 +
 lib/dpif-provider.h |  3 +++
 lib/ipf.c           | 23 +++++++++++++++++++++++
 lib/ipf.h           |  1 +
 10 files changed, 98 insertions(+)

diff --git a/NEWS b/NEWS
index cedc726..ea354a1 100644
--- a/NEWS
+++ b/NEWS
@@ -13,6 +13,8 @@ Post-v2.10.0
      * Add v4/v6 fragmentation support for conntrack.
      * New ovs-appctl "dpctl/ipf-set-enabled" and "dpctl/ipf-set-disabled"
        commands for userspace datapath conntrack fragmentation support.
+     * New "ovs-appctl dpctl/ipf-set-min-frag" command for userspace
+       datapath conntrack fragmentation support.
    - DPDK:
      * Add option for simple round-robin based Rxq to PMD assignment.
        It can be set with pmd-rxq-assign.
diff --git a/lib/ct-dpif.c b/lib/ct-dpif.c
index edb14f8..d3dad70 100644
--- a/lib/ct-dpif.c
+++ b/lib/ct-dpif.c
@@ -202,6 +202,14 @@ ct_dpif_ipf_set_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 d61cf71..dca75b7 100644
--- a/lib/ct-dpif.h
+++ b/lib/ct-dpif.h
@@ -213,6 +213,7 @@ int ct_dpif_get_limits(struct dpif *dpif, uint32_t *default_limit,
                        const struct ovs_list *, struct ovs_list *);
 int ct_dpif_del_limits(struct dpif *dpif, const struct ovs_list *);
 int ct_dpif_ipf_set_enabled(struct dpif *, bool v6, bool enable);
+int ct_dpif_ipf_set_min_frag(struct dpif *, bool v6, uint32_t min_frag);
 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 d6dac73..72d6c45 100644
--- a/lib/dpctl.c
+++ b/lib/dpctl.c
@@ -1962,6 +1962,44 @@ dpctl_ipf_set_disabled(int argc, const char *argv[],
     return ipf_set_enabled__(argc, argv, dpctl_p, false);
 }
 
+static int
+dpctl_ipf_set_min_frag(int argc, const char *argv[],
+                       struct dpctl_params *dpctl_p)
+{
+    struct dpif *dpif;
+    int error = opt_dpif_open(argc, argv, dpctl_p, 4, &dpif);
+    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,
+                                "requested minimum fragment size too small;"
+                                " see documentation");
+                }
+            } 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
@@ -2269,6 +2307,8 @@ static const struct dpctl_command all_commands[] = {
         DP_RO },
     { "ipf-set-enabled", "[dp] v4|v6", 1, 2, dpctl_ipf_set_enabled, DP_RW },
     { "ipf-set-disabled", "[dp] v4|v6", 1, 2, dpctl_ipf_set_disabled, DP_RW },
+    { "ipf-set-min-frag", "[dp] v4|v6 minfragment", 2, 3,
+       dpctl_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 32c8259..9bfc8a4 100644
--- a/lib/dpctl.man
+++ b/lib/dpctl.man
@@ -229,6 +229,17 @@ Both IPv4 and IPv6 fragment reassembly are enabled by default.  Only
 supported for the userspace datapath.
 .
 .TP
+\*(DX\fBipf\-set\-min\-frag\fR [\fIdp\fR] \fBv4\fR|\fBv6\fR \fIminfrag\fR
+Sets the minimum fragment size for non-final fragments to
+\fIminfrag\fR.  Either \fBv4\fR or \fBv6\fR must be specified.  For
+enhanced DOS security, higher minimum fragment sizes can usually be used.
+The default IPv4 value is 1200 and the clamped minimum is 400.  The default
+IPv6 value is 1280, with a clamped minimum of 400, for testing
+flexibility.  The maximum fragment size is not clamped, however, setting
+this value too high might result in valid fragments being dropped.  Only
+supported for userspace datapath.
+.
+.TP
 .DO "[\fB\-m\fR | \fB\-\-more\fR] [\fB\-s\fR | \fB\-\-statistics\fR]" "\*(DX\fBdump\-conntrack\fR" "[\fIdp\fR] [\fBzone=\fIzone\fR]"
 Prints to the console all the connection entries in the tracker used by
 \fIdp\fR.  If \fBzone=\fIzone\fR is specified, only shows the connections
diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
index 56fcd7e..ebb316c 100644
--- a/lib/dpif-netdev.c
+++ b/lib/dpif-netdev.c
@@ -6930,6 +6930,13 @@ dpif_netdev_ipf_set_enabled(struct dpif *dpif OVS_UNUSED, bool v6,
     return ipf_set_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,
@@ -6982,6 +6989,7 @@ const struct dpif_class dpif_netdev_class = {
     NULL,                       /* ct_get_limits */
     NULL,                       /* ct_del_limits */
     dpif_netdev_ipf_set_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 1f452ff..30f5acf 100644
--- a/lib/dpif-netlink.c
+++ b/lib/dpif-netlink.c
@@ -3430,6 +3430,7 @@ const struct dpif_class dpif_netlink_class = {
     dpif_netlink_ct_get_limits,
     dpif_netlink_ct_del_limits,
     NULL,                       /* ipf_set_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 c379bec..28a6a97 100644
--- a/lib/dpif-provider.h
+++ b/lib/dpif-provider.h
@@ -474,6 +474,9 @@ struct dpif_class {
      * setting is enabled. */
     int (*ipf_set_enabled)(struct dpif *, bool v6, bool enabled);
 
+    /* Set minimum fragment allowed. */
+    int (*ipf_set_min_frag)(struct dpif *, bool v6, uint32_t min_frag);
+
     /* Meters */
 
     /* Queries 'dpif' for supported meter features.
diff --git a/lib/ipf.c b/lib/ipf.c
index c2f09be..f9d2de6 100644
--- a/lib/ipf.c
+++ b/lib/ipf.c
@@ -1368,3 +1368,26 @@ ipf_set_enabled(bool v6, bool enable)
     atomic_store_relaxed(v6 ? &ifp_v6_enabled : &ifp_v4_enabled, 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 a1673a6..cf221f1 100644
--- a/lib/ipf.h
+++ b/lib/ipf.h
@@ -30,5 +30,6 @@ void ipf_postprocess_conntrack(struct dp_packet_batch *pb, long long now,
 void ipf_init(void);
 void ipf_destroy(void);
 int ipf_set_enabled(bool v6, bool enable);
+int ipf_set_min_frag(bool v6, uint32_t value);
 
 #endif /* ipf.h */
-- 
1.9.1



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