MPLS Unifom mode

- support both pipe and uniform modes for all MPLS LSP
- all API programming for output-labels requires that the mode (and associated data) is specificed
   - API changes in MPLS, BIER and IP are involved
- new DPO [sub] types for MPLS labels to handle the two modes.

Change-Id: I87b76401e996f10dfbdbe4552ff6b19af958783c
Signed-off-by: Neale Ranns <nranns@cisco.com>

1 files changed, 844 insertions, 231 deletions

diff --git a/src/vnet/dpo/mpls_label_dpo.c b/src/vnet/dpo/mpls_label_dpo.c
index fa5177ab9ea..954d637937b 100644
--- a/src/vnet/dpo/mpls_label_dpo.c
+++ b/src/vnet/dpo/mpls_label_dpo.c
@@ -23,6 +23,17 @@
  */
 mpls_label_dpo_t *mpls_label_dpo_pool;
 
+/**
+ * Strings for the flags
+ */
+const char* mpls_label_dpo_attr_names[] = MPLS_LABEL_DPO_ATTR_NAMES;
+
+/**
+ * registered DPO types for each of the label sub-types. And there's a
+ * subtype for each of the flag combinations.
+ */
+static dpo_type_t mpls_label_dpo_types[1 << MPLS_LABEL_DPO_ATTR_MAX];
+
 static mpls_label_dpo_t *
 mpls_label_dpo_alloc (void)
 {
@@ -42,70 +53,138 @@ mpls_label_dpo_get_index (mpls_label_dpo_t *mld)
     return (mld - mpls_label_dpo_pool);
 }
 
-index_t
-mpls_label_dpo_create (mpls_label_t *label_stack,
+void
+mpls_label_dpo_create (fib_mpls_label_t *label_stack,
                        mpls_eos_bit_t eos,
-                       u8 ttl,
-                       u8 exp,
                        dpo_proto_t payload_proto,
-		       const dpo_id_t *dpo)
+                       mpls_label_dpo_flags_t flags,
+		       const dpo_id_t *parent,
+                       dpo_id_t *dpo)
 {
     mpls_label_dpo_t *mld;
+    dpo_type_t dtype;
     u32 ii;
 
+    if ((DPO_PROTO_IP4 != payload_proto) &&
+        (DPO_PROTO_IP6 != payload_proto))
+    {
+        /*
+         * remove unsupported configuration
+         */
+        flags &= ~MPLS_LABEL_DPO_FLAG_NO_IP_TTL_DECR;
+    }
+
     mld = mpls_label_dpo_alloc();
+    mld->mld_flags = flags;
+    dtype = mpls_label_dpo_types[flags];
 
     if (MPLS_LABEL_DPO_MAX_N_LABELS < vec_len(label_stack))
     {
         clib_warning("Label stack size exceeded");
-        dpo_stack(DPO_MPLS_LABEL,
+        dpo_stack(dtype,
                   mld->mld_payload_proto,
                   &mld->mld_dpo,
                   drop_dpo_get(DPO_PROTO_MPLS));
-        return (mpls_label_dpo_get_index(mld));
     }
+    else
+    {
+        mld->mld_n_labels = vec_len(label_stack);
+        mld->mld_n_hdr_bytes = mld->mld_n_labels * sizeof(mld->mld_hdr[0]);
+        mld->mld_payload_proto = payload_proto;
+
+        /*
+         * construct label rewrite headers for each value passed.
+         * get the header in network byte order since we will paint it
+         * on a packet in the data-plane
+         */
+        for (ii = 0; ii < mld->mld_n_labels-1; ii++)
+        {
+            vnet_mpls_uc_set_label(&mld->mld_hdr[ii].label_exp_s_ttl,
+                                   label_stack[ii].fml_value);
+            vnet_mpls_uc_set_exp(&mld->mld_hdr[ii].label_exp_s_ttl,
+                                 label_stack[ii].fml_exp);
+            vnet_mpls_uc_set_s(&mld->mld_hdr[ii].label_exp_s_ttl,
+                               MPLS_NON_EOS);
+            if (0 != label_stack[ii].fml_ttl)
+            {
+                vnet_mpls_uc_set_ttl(&mld->mld_hdr[ii].label_exp_s_ttl,
+                                     label_stack[ii].fml_ttl);
+            }
+            else
+            {
+                vnet_mpls_uc_set_ttl(&mld->mld_hdr[ii].label_exp_s_ttl,
+                                     MPLS_LABEL_DEFAULT_TTL);
+            }
+            mld->mld_hdr[ii].label_exp_s_ttl =
+                clib_host_to_net_u32(mld->mld_hdr[ii].label_exp_s_ttl);
+        }
 
-    mld->mld_n_labels = vec_len(label_stack);
-    mld->mld_n_hdr_bytes = mld->mld_n_labels * sizeof(mld->mld_hdr[0]);
-    mld->mld_payload_proto = payload_proto;
+        /*
+         * the inner most label
+         */
+        ii = mld->mld_n_labels-1;
+
+        vnet_mpls_uc_set_label(&mld->mld_hdr[ii].label_exp_s_ttl,
+                               label_stack[ii].fml_value);
+        vnet_mpls_uc_set_exp(&mld->mld_hdr[ii].label_exp_s_ttl,
+                             label_stack[ii].fml_exp);
+        vnet_mpls_uc_set_s(&mld->mld_hdr[ii].label_exp_s_ttl, eos);
+        if (0 != label_stack[ii].fml_ttl)
+        {
+            vnet_mpls_uc_set_ttl(&mld->mld_hdr[ii].label_exp_s_ttl,
+                                 label_stack[ii].fml_ttl);
+        }
+        else
+        {
+            vnet_mpls_uc_set_ttl(&mld->mld_hdr[ii].label_exp_s_ttl,
+                                 MPLS_LABEL_DEFAULT_TTL);
+        }
+        mld->mld_hdr[ii].label_exp_s_ttl =
+            clib_host_to_net_u32(mld->mld_hdr[ii].label_exp_s_ttl);
 
-    /*
-     * construct label rewrite headers for each value value passed.
-     * get the header in network byte order since we will paint it
-     * on a packet in the data-plane
-     */
+        /*
+         * pipe/uniform mode is only supported for the bottom of stack label
+         */
+        if (FIB_MPLS_LSP_MODE_UNIFORM == label_stack[ii].fml_mode)
+        {
+            mld->mld_flags |= MPLS_LABEL_DPO_FLAG_UNIFORM_MODE;
+        }
+        else
+        {
+            mld->mld_flags &= ~MPLS_LABEL_DPO_FLAG_UNIFORM_MODE;
+        }
+        dtype = mpls_label_dpo_types[mld->mld_flags];
 
-    for (ii = 0; ii < mld->mld_n_labels-1; ii++)
-    {
-	vnet_mpls_uc_set_label(&mld->mld_hdr[ii].label_exp_s_ttl, label_stack[ii]);
-	vnet_mpls_uc_set_ttl(&mld->mld_hdr[ii].label_exp_s_ttl, 255);
-	vnet_mpls_uc_set_exp(&mld->mld_hdr[ii].label_exp_s_ttl, 0);
-	vnet_mpls_uc_set_s(&mld->mld_hdr[ii].label_exp_s_ttl, MPLS_NON_EOS);
-	mld->mld_hdr[ii].label_exp_s_ttl =
-	    clib_host_to_net_u32(mld->mld_hdr[ii].label_exp_s_ttl);
+        /*
+         * stack this label object on its parent.
+         */
+        dpo_stack(dtype,
+                  mld->mld_payload_proto,
+                  &mld->mld_dpo,
+                  parent);
     }
 
-    /*
-     * the inner most label
-     */
-    ii = mld->mld_n_labels-1;
+    dpo_set(dpo,
+            dtype,
+            mld->mld_payload_proto,
+            mpls_label_dpo_get_index(mld));
+}
 
-    vnet_mpls_uc_set_label(&mld->mld_hdr[ii].label_exp_s_ttl, label_stack[ii]);
-    vnet_mpls_uc_set_ttl(&mld->mld_hdr[ii].label_exp_s_ttl, ttl);
-    vnet_mpls_uc_set_exp(&mld->mld_hdr[ii].label_exp_s_ttl, exp);
-    vnet_mpls_uc_set_s(&mld->mld_hdr[ii].label_exp_s_ttl, eos);
-    mld->mld_hdr[ii].label_exp_s_ttl =
-	clib_host_to_net_u32(mld->mld_hdr[ii].label_exp_s_ttl);
+u8*
+format_mpls_label_dpo_flags (u8 *s, va_list *args)
+{
+    mpls_label_dpo_flags_t flags = va_arg (*args, int);
+    mpls_label_dpo_attr_t attr;
 
-    /*
-     * stack this label objct on its parent.
-     */
-    dpo_stack(DPO_MPLS_LABEL,
-              mld->mld_payload_proto,
-              &mld->mld_dpo,
-              dpo);
+    FOR_EACH_MPLS_LABEL_DPO_ATTR(attr)
+    {
+        if ((1 << attr) & flags)
+        {
+            s = format(s, "%s,", mpls_label_dpo_attr_names[attr]);
+        }
+    }
 
-    return (mpls_label_dpo_get_index(mld));
+    return (s);
 }
 
 u8*
@@ -117,17 +196,18 @@ format_mpls_label_dpo (u8 *s, va_list *args)
     mpls_label_dpo_t *mld;
     u32 ii;
 
-    s = format(s, "mpls-label:[%d]:", index);
-
     if (pool_is_free_index(mpls_label_dpo_pool, index))
     {
         /*
          * the packet trace can be printed after the DPO has been deleted
          */
-        return (s);
+        return (format(s, "mpls-label[???,%d]:", index));
     }
 
     mld = mpls_label_dpo_get(index);
+    s = format(s, "mpls-label[%U%d]:",
+               format_mpls_label_dpo_flags,
+               (int) mld->mld_flags, index);
 
     for (ii = 0; ii < mld->mld_n_labels; ii++)
     {
@@ -178,12 +258,21 @@ typedef struct mpls_label_imposition_trace_t_
      * The MPLS header imposed
      */
     mpls_unicast_header_t hdr;
+
+    /**
+     * TTL imposed - only valid for uniform LSPs
+     */
+    u8 ttl;
+
+    /**
+     * TTL imposed - only valid for uniform LSPs
+     */
+    u8 exp;
 } mpls_label_imposition_trace_t;
 
 always_inline mpls_unicast_header_t *
 mpls_label_paint (vlib_buffer_t * b0,
-                  mpls_label_dpo_t *mld0,
-                  u8 ttl0)
+                  mpls_label_dpo_t *mld0)
 {
     mpls_unicast_header_t *hdr0;
 
@@ -201,19 +290,74 @@ mpls_label_paint (vlib_buffer_t * b0,
         clib_memcpy(hdr0, mld0->mld_hdr, mld0->mld_n_hdr_bytes);
         hdr0 = hdr0 + (mld0->mld_n_labels - 1);
     }
+
+    return (hdr0);
+}
+
+/**
+ * Paint on an MPLS label and fixup the TTL
+ */
+always_inline mpls_unicast_header_t *
+mpls_label_paint_w_ttl (vlib_buffer_t * b0,
+                        mpls_label_dpo_t *mld0,
+                        u8 ttl0)
+{
+    mpls_unicast_header_t *hdr0;
+
+    hdr0 = mpls_label_paint(b0, mld0);
+
     /* fixup the TTL for the inner most label */
     ((char*)hdr0)[3] = ttl0;
 
     return (hdr0);
 }
 
+/**
+ * Paint on an MPLS label and fixup the TTL and EXP bits.
+ */
+always_inline mpls_unicast_header_t *
+mpls_label_paint_w_ttl_exp (vlib_buffer_t * b0,
+                            mpls_label_dpo_t *mld0,
+                            u8 ttl0,
+                            u8 exp0)
+{
+    mpls_unicast_header_t *hdr0;
+
+    hdr0 = mpls_label_paint_w_ttl(b0, mld0, ttl0);
+
+    /* fixup the EXP for the inner most label */
+    ((char*)hdr0)[2] |= (exp0 << 1);
+
+    return (hdr0);
+}
+
+/**
+ * Paint on an MPLS label and fixup the TTL and EXP bits
+ * When the EXP bits are *already* bit shift to the correct place in
+ * in the 2nd byte (i.e. they were read from another label)
+ */
+always_inline mpls_unicast_header_t *
+mpls_label_paint_w_ttl_mpls_exp (vlib_buffer_t * b0,
+                                 mpls_label_dpo_t *mld0,
+                                 u8 ttl0,
+                                 u8 exp0)
+{
+    mpls_unicast_header_t *hdr0;
+
+    hdr0 = mpls_label_paint_w_ttl(b0, mld0, ttl0);
+
+    /* fixup the EXP for the inner most label */
+    ((char*)hdr0)[2] |= exp0;
+
+    return (hdr0);
+}
+
 always_inline uword
 mpls_label_imposition_inline (vlib_main_t * vm,
                               vlib_node_runtime_t * node,
                               vlib_frame_t * from_frame,
-                              u8 payload_is_ip4,
-                              u8 payload_is_ip6,
-                              u8 payload_is_ethernet)
+                              const dpo_proto_t dproto,
+                              const mpls_label_dpo_flags_t flags)
 {
     u32 n_left_from, next_index, * from, * to_next;
 
@@ -235,7 +379,8 @@ mpls_label_imposition_inline (vlib_main_t * vm,
             mpls_label_dpo_t *mld0, *mld1, *mld2, *mld3;
             vlib_buffer_t * b0, *b1, * b2, *b3;
             u32 next0, next1, next2, next3;
-            u8 ttl0, ttl1,ttl2, ttl3 ;
+            u8 ttl0, ttl1, ttl2, ttl3;
+            u8 exp0, exp1, exp2, exp3;
 
             bi0 = to_next[0] = from[0];
             bi1 = to_next[1] = from[1];
@@ -282,141 +427,247 @@ mpls_label_imposition_inline (vlib_main_t * vm,
             mld2 = mpls_label_dpo_get(mldi2);
             mld3 = mpls_label_dpo_get(mldi3);
 
-            if (payload_is_ip4)
+            if (DPO_PROTO_MPLS != dproto)
             {
                 /*
-                 * decrement the TTL on ingress to the LSP
+                 * These are the non-MPLS payload imposition cases
                  */
-                ip4_header_t * ip0 = vlib_buffer_get_current(b0);
-                ip4_header_t * ip1 = vlib_buffer_get_current(b1);
-                ip4_header_t * ip2 = vlib_buffer_get_current(b2);
-                ip4_header_t * ip3 = vlib_buffer_get_current(b3);
-                u32 checksum0;
-                u32 checksum1;
-                u32 checksum2;
-                u32 checksum3;
-
-                checksum0 = ip0->checksum + clib_host_to_net_u16 (0x0100);
-                checksum1 = ip1->checksum + clib_host_to_net_u16 (0x0100);
-                checksum2 = ip2->checksum + clib_host_to_net_u16 (0x0100);
-                checksum3 = ip3->checksum + clib_host_to_net_u16 (0x0100);
-
-                checksum0 += checksum0 >= 0xffff;
-                checksum1 += checksum1 >= 0xffff;
-                checksum2 += checksum2 >= 0xffff;
-                checksum3 += checksum3 >= 0xffff;
-
-                ip0->checksum = checksum0;
-                ip1->checksum = checksum1;
-                ip2->checksum = checksum2;
-                ip3->checksum = checksum3;
-
-                ip0->ttl -= 1;
-                ip1->ttl -= 1;
-                ip2->ttl -= 1;
-                ip3->ttl -= 1;
-
-                ttl1 = ip1->ttl;
-                ttl0 = ip0->ttl;
-                ttl3 = ip3->ttl;
-                ttl2 = ip2->ttl;
-            }
-            else if (payload_is_ip6)
-            {
-                /*
-                 * decrement the TTL on ingress to the LSP
-                 */
-                ip6_header_t * ip0 = vlib_buffer_get_current(b0);
-                ip6_header_t * ip1 = vlib_buffer_get_current(b1);
-                ip6_header_t * ip2 = vlib_buffer_get_current(b2);
-                ip6_header_t * ip3 = vlib_buffer_get_current(b3);
-
-                ip0->hop_limit -= 1;
-                ip1->hop_limit -= 1;
-                ip2->hop_limit -= 1;
-                ip3->hop_limit -= 1;
-
-                ttl0 = ip0->hop_limit;
-                ttl1 = ip1->hop_limit;
-                ttl2 = ip2->hop_limit;
-                ttl3 = ip3->hop_limit;
-            }
-            else if (payload_is_ethernet)
-            {
+                if (DPO_PROTO_IP4 == dproto)
+                {
+                    ip4_header_t * ip0 = vlib_buffer_get_current(b0);
+                    ip4_header_t * ip1 = vlib_buffer_get_current(b1);
+                    ip4_header_t * ip2 = vlib_buffer_get_current(b2);
+                    ip4_header_t * ip3 = vlib_buffer_get_current(b3);
+
+                    if (!(MPLS_LABEL_DPO_FLAG_NO_IP_TTL_DECR & flags))
+                    {
+                        /*
+                         * decrement the TTL on ingress to the LSP
+                         */
+                        u32 checksum0;
+                        u32 checksum1;
+                        u32 checksum2;
+                        u32 checksum3;
+
+                        checksum0 = ip0->checksum + clib_host_to_net_u16 (0x0100);
+                        checksum1 = ip1->checksum + clib_host_to_net_u16 (0x0100);
+                        checksum2 = ip2->checksum + clib_host_to_net_u16 (0x0100);
+                        checksum3 = ip3->checksum + clib_host_to_net_u16 (0x0100);
+
+                        checksum0 += checksum0 >= 0xffff;
+                        checksum1 += checksum1 >= 0xffff;
+                        checksum2 += checksum2 >= 0xffff;
+                        checksum3 += checksum3 >= 0xffff;
+
+                        ip0->checksum = checksum0;
+                        ip1->checksum = checksum1;
+                        ip2->checksum = checksum2;
+                        ip3->checksum = checksum3;
+
+                        ip0->ttl -= 1;
+                        ip1->ttl -= 1;
+                        ip2->ttl -= 1;
+                        ip3->ttl -= 1;
+                    }
+
+                    if (flags & MPLS_LABEL_DPO_FLAG_UNIFORM_MODE)
+                    {
+                        ttl1 = ip1->ttl;
+                        ttl0 = ip0->ttl;
+                        ttl3 = ip3->ttl;
+                        ttl2 = ip2->ttl;
+                        /* by default copy the 3 most significant bits */
+                        exp0 = ip_dscp_to_mpls_exp(ip0->tos);
+                        exp1 = ip_dscp_to_mpls_exp(ip1->tos);
+                        exp2 = ip_dscp_to_mpls_exp(ip2->tos);
+                        exp3 = ip_dscp_to_mpls_exp(ip3->tos);
+                    }
+                }
+                else if (DPO_PROTO_IP6 == dproto)
+                {
+                    /*
+                     * decrement the TTL on ingress to the LSP
+                     */
+                    ip6_header_t * ip0 = vlib_buffer_get_current(b0);
+                    ip6_header_t * ip1 = vlib_buffer_get_current(b1);
+                    ip6_header_t * ip2 = vlib_buffer_get_current(b2);
+                    ip6_header_t * ip3 = vlib_buffer_get_current(b3);
+
+                    if (!(MPLS_LABEL_DPO_FLAG_NO_IP_TTL_DECR & flags))
+                    {
+                        ip0->hop_limit -= 1;
+                        ip1->hop_limit -= 1;
+                        ip2->hop_limit -= 1;
+                        ip3->hop_limit -= 1;
+                    }
+                    if (flags & MPLS_LABEL_DPO_FLAG_UNIFORM_MODE)
+                    {
+                        ttl0 = ip0->hop_limit;
+                        ttl1 = ip1->hop_limit;
+                        ttl2 = ip2->hop_limit;
+                        ttl3 = ip3->hop_limit;
+                        /* by default copy the 3 most significant bits */
+                        exp0 = ip_dscp_to_mpls_exp(
+                            ip6_traffic_class_network_order(ip0));
+                        exp1 = ip_dscp_to_mpls_exp(
+                            ip6_traffic_class_network_order(ip1));
+                        exp2 = ip_dscp_to_mpls_exp(
+                            ip6_traffic_class_network_order(ip2));
+                        exp3 = ip_dscp_to_mpls_exp(
+                            ip6_traffic_class_network_order(ip3));
+                    }
+                }
+                else
+                {
+                    /*
+                     * nothing to change in the ethernet header
+                     */
+                    ttl0 = ttl1 = ttl2 = ttl3 = MPLS_LABEL_DEFAULT_TTL;
+                    exp0 = exp1 = exp2 = exp3 = MPLS_LABEL_DEFAULT_EXP;
+                }
                 /*
-                 * nothing to chang ein the ethernet header
+                 * These are the non-MPLS payload imposition cases.
+                 * Based on the LSP mode either, for uniform, copy down the TTL
+                 * and EXP from the payload or, for pipe mode, slap on the value
+                 * requested from config
                  */
-                ttl0 = ttl1 = ttl2 = ttl3 = 255;
+                if (flags & MPLS_LABEL_DPO_FLAG_UNIFORM_MODE)
+                {
+                    hdr0 = mpls_label_paint_w_ttl_exp(b0, mld0, ttl0, exp0);
+                    hdr1 = mpls_label_paint_w_ttl_exp(b1, mld1, ttl1, exp1);
+                    hdr2 = mpls_label_paint_w_ttl_exp(b2, mld2, ttl2, exp2);
+                    hdr3 = mpls_label_paint_w_ttl_exp(b3, mld3, ttl3, exp3);
+                }
+                else
+                {
+                    hdr0 = mpls_label_paint(b0, mld0);
+                    hdr1 = mpls_label_paint(b1, mld1);
+                    hdr2 = mpls_label_paint(b2, mld2);
+                    hdr3 = mpls_label_paint(b3, mld3);
+                }
             }
             else
             {
                 /*
                  * else, the packet to be encapped is an MPLS packet
+                 * there are two cases to consider:
+                 *  1 - this is an MPLS label swap at an LSP midpoint.
+                 *      recognisable because mpls.first = 1. In this case the
+                 *      TTL must be set to the current value -1.
+                 *  2 - The MPLS packet is recursing (or being injected into)
+                 *      this LSP, in which case the pipe/uniform rules apply
+                 *
                  */
                 if (PREDICT_TRUE(vnet_buffer(b0)->mpls.first))
                 {
                     /*
-                     * The first label to be imposed on the packet. this is a label swap.
-                     * in which case we stashed the TTL and EXP bits in the
-                     * packet in the lookup node
+                     * The first label to be imposed on the packet. this is a
+                     * label swap.in which case we stashed the TTL and EXP bits
+                     * in the packet in the lookup node
                      */
                     ASSERT(0 != vnet_buffer (b0)->mpls.ttl);
 
                     ttl0 = vnet_buffer(b0)->mpls.ttl - 1;
+                    exp0 = vnet_buffer(b0)->mpls.exp;
+                    hdr0 = mpls_label_paint_w_ttl_exp(b0, mld0, ttl0, exp0);
                 }
                 else
                 {
                     /*
-                     * not the first label. implying we are recusring down a chain of
-                     * output labels.
-                     * Each layer is considered a new LSP - hence the TTL is reset.
+                     * not the first label. implying we are recusring down a
+                     * chain of output labels. Each layer is considered a new
+                     * LSP - hence the TTL/EXP are pipe/uniform handled
                      */
-                    ttl0 = 255;
+                    if (flags & MPLS_LABEL_DPO_FLAG_UNIFORM_MODE)
+                    {
+                        hdr0 = vlib_buffer_get_current(b0);
+                        ttl0 = ((u8*)hdr0)[3];
+                        exp0 = ((u8*)hdr0)[2] & 0xe;
+                        hdr0 = mpls_label_paint_w_ttl_mpls_exp(b0, mld0, ttl0, exp0);
+                    }
+                    else
+                    {
+                        hdr0 = mpls_label_paint(b0, mld0);
+                    }
                 }
                 if (PREDICT_TRUE(vnet_buffer(b1)->mpls.first))
                 {
-                    ASSERT(1 != vnet_buffer (b1)->mpls.ttl);
+                    ASSERT(0 != vnet_buffer (b1)->mpls.ttl);
+
                     ttl1 = vnet_buffer(b1)->mpls.ttl - 1;
+                    exp1 = vnet_buffer(b1)->mpls.exp;
+                    hdr1 = mpls_label_paint_w_ttl_exp(b1, mld1, ttl1, exp1);
                 }
                 else
                 {
-                    ttl1 = 255;
+                    if (flags & MPLS_LABEL_DPO_FLAG_UNIFORM_MODE)
+                    {
+                        hdr1 = vlib_buffer_get_current(b1);
+                        ttl1 = ((u8*)hdr1)[3];
+                        exp1 = ((u8*)hdr1)[2] & 0xe;
+                        hdr1 = mpls_label_paint_w_ttl_mpls_exp(b1, mld1, ttl1, exp1);
+                    }
+                    else
+                    {
+                        hdr1 = mpls_label_paint(b1, mld1);
+                    }
                 }
                 if (PREDICT_TRUE(vnet_buffer(b2)->mpls.first))
                 {
-                    ASSERT(1 != vnet_buffer (b2)->mpls.ttl);
+                    ASSERT(0 != vnet_buffer (b2)->mpls.ttl);
 
                     ttl2 = vnet_buffer(b2)->mpls.ttl - 1;
+                    exp2 = vnet_buffer(b2)->mpls.exp;
+                    hdr2 = mpls_label_paint_w_ttl_exp(b2, mld2, ttl2, exp2);
                 }
                 else
                 {
-                    ttl2 = 255;
+                    if (flags & MPLS_LABEL_DPO_FLAG_UNIFORM_MODE)
+                    {
+                        hdr2 = vlib_buffer_get_current(b2);
+                        ttl2 = ((u8*)hdr2)[3];
+                        exp2 = ((u8*)hdr2)[2] & 0xe;
+                        hdr2 = mpls_label_paint_w_ttl_mpls_exp(b2, mld2, ttl2, exp2);
+                    }
+                    else
+                    {
+                        hdr2 = mpls_label_paint(b2, mld2);
+                    }
                 }
                 if (PREDICT_TRUE(vnet_buffer(b3)->mpls.first))
                 {
-                    ASSERT(1 != vnet_buffer (b3)->mpls.ttl);
+                    ASSERT(0 != vnet_buffer (b3)->mpls.ttl);
+
                     ttl3 = vnet_buffer(b3)->mpls.ttl - 1;
+                    exp3 = vnet_buffer(b0)->mpls.exp;
+                    hdr3 = mpls_label_paint_w_ttl_exp(b3, mld3, ttl3, exp3);
                 }
                 else
                 {
-                    ttl3 = 255;
+                    if (flags & MPLS_LABEL_DPO_FLAG_UNIFORM_MODE)
+                    {
+                        hdr3 = vlib_buffer_get_current(b3);
+                        ttl3 = ((u8*)hdr3)[3];
+                        exp3 = ((u8*)hdr3)[2] & 0xe;
+                        hdr3 = mpls_label_paint_w_ttl_mpls_exp(b3, mld3, ttl3, exp3);
+                    }
+                    else
+                    {
+                        hdr3 = mpls_label_paint(b3, mld3);
+                    }
                 }
-            }
-            vnet_buffer(b0)->mpls.first = 0;
-            vnet_buffer(b1)->mpls.first = 0;
-            vnet_buffer(b2)->mpls.first = 0;
-            vnet_buffer(b3)->mpls.first = 0;
 
-            /* Paint the MPLS header */
-            hdr0 = mpls_label_paint(b0, mld0, ttl0);
-            hdr1 = mpls_label_paint(b1, mld1, ttl1);
-            hdr2 = mpls_label_paint(b2, mld2, ttl2);
-            hdr3 = mpls_label_paint(b3, mld3, ttl3);
+                vnet_buffer(b0)->mpls.first = 0;
+                vnet_buffer(b1)->mpls.first = 0;
+                vnet_buffer(b2)->mpls.first = 0;
+                vnet_buffer(b3)->mpls.first = 0;
+            }
 
             next0 = mld0->mld_dpo.dpoi_next_node;
             next1 = mld1->mld_dpo.dpoi_next_node;
             next2 = mld2->mld_dpo.dpoi_next_node;
             next3 = mld3->mld_dpo.dpoi_next_node;
+
             vnet_buffer(b0)->ip.adj_index[VLIB_TX] = mld0->mld_dpo.dpoi_index;
             vnet_buffer(b1)->ip.adj_index[VLIB_TX] = mld1->mld_dpo.dpoi_index;
             vnet_buffer(b2)->ip.adj_index[VLIB_TX] = mld2->mld_dpo.dpoi_index;
@@ -427,24 +678,60 @@ mpls_label_imposition_inline (vlib_main_t * vm,
                 mpls_label_imposition_trace_t *tr =
                     vlib_add_trace (vm, node, b0, sizeof (*tr));
                 tr->hdr = *hdr0;
+                if (flags & MPLS_LABEL_DPO_FLAG_UNIFORM_MODE)
+                {
+                    tr->ttl = ttl0;
+                    tr->exp = exp0;
+                }
+                else
+                {
+                    tr->ttl = tr->exp = 0;
+                }
             }
             if (PREDICT_FALSE(b1->flags & VLIB_BUFFER_IS_TRACED))
             {
                 mpls_label_imposition_trace_t *tr =
                     vlib_add_trace (vm, node, b1, sizeof (*tr));
                 tr->hdr = *hdr1;
+                if (flags & MPLS_LABEL_DPO_FLAG_UNIFORM_MODE)
+                {
+                    tr->ttl = ttl1;
+                    tr->exp = exp1;
+                }
+                else
+                {
+                    tr->ttl = tr->exp = 0;
+                }
             }
             if (PREDICT_FALSE(b2->flags & VLIB_BUFFER_IS_TRACED))
             {
                 mpls_label_imposition_trace_t *tr =
                     vlib_add_trace (vm, node, b2, sizeof (*tr));
                 tr->hdr = *hdr2;
+                if (flags & MPLS_LABEL_DPO_FLAG_UNIFORM_MODE)
+                {
+                    tr->ttl = ttl2;
+                    tr->exp = exp2;
+                }
+                else
+                {
+                    tr->ttl = tr->exp = 0;
+                }
             }
             if (PREDICT_FALSE(b3->flags & VLIB_BUFFER_IS_TRACED))
             {
                 mpls_label_imposition_trace_t *tr =
                     vlib_add_trace (vm, node, b3, sizeof (*tr));
                 tr->hdr = *hdr3;
+                if (flags & MPLS_LABEL_DPO_FLAG_UNIFORM_MODE)
+                {
+                    tr->ttl = ttl3;
+                    tr->exp = exp3;
+                }
+                else
+                {
+                    tr->ttl = tr->exp = 0;
+                }
             }
 
             vlib_validate_buffer_enqueue_x4(vm, node, next_index, to_next,
@@ -459,8 +746,8 @@ mpls_label_imposition_inline (vlib_main_t * vm,
             mpls_label_dpo_t *mld0;
             vlib_buffer_t * b0;
             u32 bi0, mldi0;
+            u8 ttl0, exp0;
             u32 next0;
-            u8 ttl;
 
             bi0 = from[0];
             to_next[0] = bi0;
@@ -475,67 +762,99 @@ mpls_label_imposition_inline (vlib_main_t * vm,
             mldi0 = vnet_buffer(b0)->ip.adj_index[VLIB_TX];
             mld0 = mpls_label_dpo_get(mldi0);
 
-            if (payload_is_ip4)
+            if (DPO_PROTO_MPLS != dproto)
             {
-                /*
-                 * decrement the TTL on ingress to the LSP
-                 */
-                ip4_header_t * ip0 = vlib_buffer_get_current(b0);
-                u32 checksum0;
-
-                checksum0 = ip0->checksum + clib_host_to_net_u16 (0x0100);
-                checksum0 += checksum0 >= 0xffff;
+                if (DPO_PROTO_IP4 == dproto)
+                {
+                    /*
+                     * decrement the TTL on ingress to the LSP
+                     */
+                    ip4_header_t * ip0 = vlib_buffer_get_current(b0);
+                    if (!(MPLS_LABEL_DPO_FLAG_NO_IP_TTL_DECR & flags))
+                    {
+                        u32 checksum0;
+
+                        checksum0 = ip0->checksum + clib_host_to_net_u16 (0x0100);
+                        checksum0 += checksum0 >= 0xffff;
+
+                        ip0->checksum = checksum0;
+                        ip0->ttl -= 1;
+                    }
+                    if (flags & MPLS_LABEL_DPO_FLAG_UNIFORM_MODE)
+                    {
+                        ttl0 = ip0->ttl;
+                        exp0 = ip_dscp_to_mpls_exp(ip0->tos);
+                    }
+                }
+                else if (DPO_PROTO_IP6 == dproto)
+                {
+                    /*
+                     * decrement the TTL on ingress to the LSP
+                     */
+                    ip6_header_t * ip0 = vlib_buffer_get_current(b0);
+
+                    if (!(MPLS_LABEL_DPO_FLAG_NO_IP_TTL_DECR & flags))
+                    {
+                        ip0->hop_limit -= 1;
+                    }
+                    if (flags & MPLS_LABEL_DPO_FLAG_UNIFORM_MODE)
+                    {
+                        ttl0 = ip0->hop_limit;
+                        exp0 = ip_dscp_to_mpls_exp(
+                            ip6_traffic_class_network_order(ip0));
+                    }
+                }
+                else
+                {
+                    /*
+                     * nothing to change in the ethernet header
+                     */
+                    ttl0 = MPLS_LABEL_DEFAULT_TTL;
+                    exp0 = MPLS_LABEL_DEFAULT_EXP;
+                }
 
-                ip0->checksum = checksum0;
-                ip0->ttl -= 1;
-                ttl = ip0->ttl;
-            }
-            else if (payload_is_ip6)
-            {
                 /*
-                 * decrement the TTL on ingress to the LSP
+                 * These are the non-MPLS payload imposition cases.
+                 * Based on the LSP mode either, for uniform, copy down the TTL
+                 * from the payload or, for pipe mode, slap on the value
+                 * requested from config
                  */
-                ip6_header_t * ip0 = vlib_buffer_get_current(b0);
-
-                ip0->hop_limit -= 1;
-                ttl = ip0->hop_limit;
+                if (flags & MPLS_LABEL_DPO_FLAG_UNIFORM_MODE)
+                {
+                    hdr0 = mpls_label_paint_w_ttl_exp(b0, mld0, ttl0, exp0);
+                }
+                else
+                {
+                    hdr0 = mpls_label_paint(b0, mld0);
+                }
             }
             else
             {
-                /*
-                 * else, the packet to be encapped is an MPLS packet
-                 */
-                if (vnet_buffer(b0)->mpls.first)
+                if (PREDICT_TRUE(vnet_buffer(b0)->mpls.first))
                 {
-                    /*
-                     * The first label to be imposed on the packet. this is a label swap.
-                     * in which case we stashed the TTL and EXP bits in the
-                     * packet in the lookup node
-                     */
                     ASSERT(0 != vnet_buffer (b0)->mpls.ttl);
 
-                    ttl = vnet_buffer(b0)->mpls.ttl - 1;
+                    ttl0 = vnet_buffer(b0)->mpls.ttl - 1;
+                    exp0 = vnet_buffer(b0)->mpls.exp;
+                    hdr0 = mpls_label_paint_w_ttl_exp(b0, mld0, ttl0, exp0);
                 }
                 else
                 {
-                    /*
-                     * not the first label. implying we are recusring down a chain of
-                     * output labels.
-                     * Each layer is considered a new LSP - hence the TTL is reset.
-                     */
-                    ttl = 255;
+                    if (flags & MPLS_LABEL_DPO_FLAG_UNIFORM_MODE)
+                    {
+                        hdr0 = vlib_buffer_get_current(b0);
+                        ttl0 = ((u8*)hdr0)[3];
+                        exp0 = ((u8*)hdr0)[2] & 0xe;
+                        hdr0 = mpls_label_paint_w_ttl_mpls_exp(b0, mld0, ttl0, exp0);
+                    }
+                    else
+                    {
+                        hdr0 = mpls_label_paint(b0, mld0);
+                    }
                 }
-            }
-            vnet_buffer(b0)->mpls.first = 0;
-
-            /* Paint the MPLS header */
-            vlib_buffer_advance(b0, -(mld0->mld_n_hdr_bytes));
-            hdr0 = vlib_buffer_get_current(b0);
-            clib_memcpy(hdr0, mld0->mld_hdr, mld0->mld_n_hdr_bytes);
 
-            /* fixup the TTL for the inner most label */
-            hdr0 = hdr0 + (mld0->mld_n_labels - 1);
-            ((char*)hdr0)[3] = ttl;
+                vnet_buffer(b0)->mpls.first = 0;
+            }
 
             next0 = mld0->mld_dpo.dpoi_next_node;
             vnet_buffer(b0)->ip.adj_index[VLIB_TX] = mld0->mld_dpo.dpoi_index;
@@ -545,7 +864,16 @@ mpls_label_imposition_inline (vlib_main_t * vm,
                 mpls_label_imposition_trace_t *tr =
                     vlib_add_trace (vm, node, b0, sizeof (*tr));
                 tr->hdr = *hdr0;
-            }
+                if (flags & MPLS_LABEL_DPO_FLAG_UNIFORM_MODE)
+                {
+                    tr->ttl = ttl0;
+                    tr->exp = exp0;
+                }
+                else
+                {
+                    tr->ttl = tr->exp = 0;
+                }
+           }
 
             vlib_validate_buffer_enqueue_x1(vm, node, next_index, to_next,
                                             n_left_to_next, bi0, next0);
@@ -575,16 +903,18 @@ format_mpls_label_imposition_trace (u8 * s, va_list * args)
 }
 
 static uword
-mpls_label_imposition (vlib_main_t * vm,
-                       vlib_node_runtime_t * node,
-                       vlib_frame_t * frame)
+mpls_mpls_label_imposition_pipe (vlib_main_t * vm,
+                                 vlib_node_runtime_t * node,
+                                 vlib_frame_t * frame)
 {
-    return (mpls_label_imposition_inline(vm, node, frame, 0, 0, 0));
+    return (mpls_label_imposition_inline(vm, node, frame,
+                                         DPO_PROTO_MPLS,
+                                         MPLS_LABEL_DPO_FLAG_NONE));
 }
 
-VLIB_REGISTER_NODE (mpls_label_imposition_node) = {
-    .function = mpls_label_imposition,
-    .name = "mpls-label-imposition",
+VLIB_REGISTER_NODE (mpls_mpls_label_imposition_pipe_node) = {
+    .function = mpls_mpls_label_imposition_pipe,
+    .name = "mpls-label-imposition-pipe",
     .vector_size = sizeof (u32),
 
     .format_trace = format_mpls_label_imposition_trace,
@@ -593,20 +923,22 @@ VLIB_REGISTER_NODE (mpls_label_imposition_node) = {
         [0] = "mpls-drop",
     }
 };
-VLIB_NODE_FUNCTION_MULTIARCH (mpls_label_imposition_node,
-                              mpls_label_imposition)
+VLIB_NODE_FUNCTION_MULTIARCH (mpls_mpls_label_imposition_pipe_node,
+                              mpls_mpls_label_imposition_pipe)
 
 static uword
-ip4_mpls_label_imposition (vlib_main_t * vm,
-                           vlib_node_runtime_t * node,
-                           vlib_frame_t * frame)
+ip4_mpls_label_imposition_pipe (vlib_main_t * vm,
+                                vlib_node_runtime_t * node,
+                                vlib_frame_t * frame)
 {
-    return (mpls_label_imposition_inline(vm, node, frame, 1, 0, 0));
+    return (mpls_label_imposition_inline(vm, node, frame,
+                                         DPO_PROTO_IP4,
+                                         MPLS_LABEL_DPO_FLAG_NONE));
 }
 
-VLIB_REGISTER_NODE (ip4_mpls_label_imposition_node) = {
-    .function = ip4_mpls_label_imposition,
-    .name = "ip4-mpls-label-imposition",
+VLIB_REGISTER_NODE (ip4_mpls_label_imposition_pipe_node) = {
+    .function = ip4_mpls_label_imposition_pipe,
+    .name = "ip4-mpls-label-imposition-pipe",
     .vector_size = sizeof (u32),
 
     .format_trace = format_mpls_label_imposition_trace,
@@ -615,20 +947,22 @@ VLIB_REGISTER_NODE (ip4_mpls_label_imposition_node) = {
         [0] = "ip4-drop",
     }
 };
-VLIB_NODE_FUNCTION_MULTIARCH (ip4_mpls_label_imposition_node,
-                              ip4_mpls_label_imposition)
+VLIB_NODE_FUNCTION_MULTIARCH (ip4_mpls_label_imposition_pipe_node,
+                              ip4_mpls_label_imposition_pipe)
 
 static uword
-ip6_mpls_label_imposition (vlib_main_t * vm,
-                           vlib_node_runtime_t * node,
-                           vlib_frame_t * frame)
+ip6_mpls_label_imposition_pipe (vlib_main_t * vm,
+                                vlib_node_runtime_t * node,
+                                vlib_frame_t * frame)
 {
-    return (mpls_label_imposition_inline(vm, node, frame, 0, 1, 0));
+    return (mpls_label_imposition_inline(vm, node, frame,
+                                         DPO_PROTO_IP6,
+                                         MPLS_LABEL_DPO_FLAG_NONE));
 }
 
-VLIB_REGISTER_NODE (ip6_mpls_label_imposition_node) = {
-    .function = ip6_mpls_label_imposition,
-    .name = "ip6-mpls-label-imposition",
+VLIB_REGISTER_NODE (ip6_mpls_label_imposition_pipe_node) = {
+    .function = ip6_mpls_label_imposition_pipe,
+    .name = "ip6-mpls-label-imposition-pipe",
     .vector_size = sizeof (u32),
 
     .format_trace = format_mpls_label_imposition_trace,
@@ -637,20 +971,22 @@ VLIB_REGISTER_NODE (ip6_mpls_label_imposition_node) = {
         [0] = "ip6-drop",
     }
 };
-VLIB_NODE_FUNCTION_MULTIARCH (ip6_mpls_label_imposition_node,
-                              ip6_mpls_label_imposition)
+VLIB_NODE_FUNCTION_MULTIARCH (ip6_mpls_label_imposition_pipe_node,
+                              ip6_mpls_label_imposition_pipe)
 
 static uword
-ethernet_mpls_label_imposition (vlib_main_t * vm,
-                                vlib_node_runtime_t * node,
-                                vlib_frame_t * frame)
+ethernet_mpls_label_imposition_pipe (vlib_main_t * vm,
+                                     vlib_node_runtime_t * node,
+                                     vlib_frame_t * frame)
 {
-    return (mpls_label_imposition_inline(vm, node, frame, 0, 0, 1));
+    return (mpls_label_imposition_inline(vm, node, frame,
+                                         DPO_PROTO_ETHERNET,
+                                         MPLS_LABEL_DPO_FLAG_NONE));
 }
 
-VLIB_REGISTER_NODE (ethernet_mpls_label_imposition_node) = {
-    .function = ethernet_mpls_label_imposition,
-    .name = "ethernet-mpls-label-imposition",
+VLIB_REGISTER_NODE (ethernet_mpls_label_imposition_pipe_node) = {
+    .function = ethernet_mpls_label_imposition_pipe,
+    .name = "ethernet-mpls-label-imposition-pipe",
     .vector_size = sizeof (u32),
 
     .format_trace = format_mpls_label_imposition_trace,
@@ -659,8 +995,205 @@ VLIB_REGISTER_NODE (ethernet_mpls_label_imposition_node) = {
         [0] = "error-drop",
     }
 };
-VLIB_NODE_FUNCTION_MULTIARCH (ethernet_mpls_label_imposition_node,
-                              ethernet_mpls_label_imposition)
+
+VLIB_NODE_FUNCTION_MULTIARCH (ethernet_mpls_label_imposition_pipe_node,
+                              ethernet_mpls_label_imposition_pipe)
+
+static uword
+mpls_mpls_label_imposition_uniform (vlib_main_t * vm,
+                                    vlib_node_runtime_t * node,
+                                    vlib_frame_t * frame)
+{
+    return (mpls_label_imposition_inline(vm, node, frame,
+                                         DPO_PROTO_MPLS,
+                                         MPLS_LABEL_DPO_FLAG_UNIFORM_MODE));
+}
+
+VLIB_REGISTER_NODE (mpls_mpls_label_imposition_uniform_node) = {
+    .function = mpls_mpls_label_imposition_uniform,
+    .name = "mpls-label-imposition-uniform",
+    .vector_size = sizeof (u32),
+
+    .format_trace = format_mpls_label_imposition_trace,
+    .n_next_nodes = 1,
+    .next_nodes = {
+        [0] = "mpls-drop",
+    }
+};
+VLIB_NODE_FUNCTION_MULTIARCH (mpls_mpls_label_imposition_uniform_node,
+                              mpls_mpls_label_imposition_uniform)
+
+static uword
+ip4_mpls_label_imposition_uniform (vlib_main_t * vm,
+                                   vlib_node_runtime_t * node,
+                                   vlib_frame_t * frame)
+{
+    return (mpls_label_imposition_inline(vm, node, frame,
+                                         DPO_PROTO_IP4,
+                                         MPLS_LABEL_DPO_FLAG_UNIFORM_MODE));
+}
+
+VLIB_REGISTER_NODE (ip4_mpls_label_imposition_uniform_node) = {
+    .function = ip4_mpls_label_imposition_uniform,
+    .name = "ip4-mpls-label-imposition-uniform",
+    .vector_size = sizeof (u32),
+
+    .format_trace = format_mpls_label_imposition_trace,
+    .n_next_nodes = 1,
+    .next_nodes = {
+        [0] = "ip4-drop",
+    }
+};
+VLIB_NODE_FUNCTION_MULTIARCH (ip4_mpls_label_imposition_uniform_node,
+                              ip4_mpls_label_imposition_uniform)
+
+static uword
+ip6_mpls_label_imposition_uniform (vlib_main_t * vm,
+                                   vlib_node_runtime_t * node,
+                                   vlib_frame_t * frame)
+{
+    return (mpls_label_imposition_inline(vm, node, frame,
+                                         DPO_PROTO_IP6,
+                                         MPLS_LABEL_DPO_FLAG_UNIFORM_MODE));
+}
+
+VLIB_REGISTER_NODE (ip6_mpls_label_imposition_uniform_node) = {
+    .function = ip6_mpls_label_imposition_uniform,
+    .name = "ip6-mpls-label-imposition-uniform",
+    .vector_size = sizeof (u32),
+
+    .format_trace = format_mpls_label_imposition_trace,
+    .n_next_nodes = 1,
+    .next_nodes = {
+        [0] = "ip6-drop",
+    }
+};
+VLIB_NODE_FUNCTION_MULTIARCH (ip6_mpls_label_imposition_uniform_node,
+                              ip6_mpls_label_imposition_uniform)
+
+static uword
+ethernet_mpls_label_imposition_uniform (vlib_main_t * vm,
+                                        vlib_node_runtime_t * node,
+                                        vlib_frame_t * frame)
+{
+    return (mpls_label_imposition_inline(vm, node, frame,
+                                         DPO_PROTO_ETHERNET,
+                                         MPLS_LABEL_DPO_FLAG_UNIFORM_MODE));
+}
+
+VLIB_REGISTER_NODE (ethernet_mpls_label_imposition_uniform_node) = {
+    .function = ethernet_mpls_label_imposition_uniform,
+    .name = "ethernet-mpls-label-imposition-uniform",
+    .vector_size = sizeof (u32),
+
+    .format_trace = format_mpls_label_imposition_trace,
+    .n_next_nodes = 1,
+    .next_nodes = {
+        [0] = "error-drop",
+    }
+};
+
+VLIB_NODE_FUNCTION_MULTIARCH (ethernet_mpls_label_imposition_uniform_node,
+                              ethernet_mpls_label_imposition_uniform)
+
+static uword
+ip4_mpls_label_imposition_pipe_no_ip_ttl_decr (vlib_main_t * vm,
+                                               vlib_node_runtime_t * node,
+                                               vlib_frame_t * frame)
+{
+    return (mpls_label_imposition_inline(vm, node, frame,
+                                         DPO_PROTO_IP4,
+                                         MPLS_LABEL_DPO_FLAG_NO_IP_TTL_DECR));
+}
+
+VLIB_REGISTER_NODE (ip4_mpls_label_imposition_pipe_no_ip_ttl_decr_node) = {
+    .function = ip4_mpls_label_imposition_pipe_no_ip_ttl_decr,
+    .name = "ip4-mpls-label-imposition-pipe-no-ip-ttl-decr",
+    .vector_size = sizeof (u32),
+
+    .format_trace = format_mpls_label_imposition_trace,
+    .n_next_nodes = 1,
+    .next_nodes = {
+        [0] = "ip4-drop",
+    }
+};
+VLIB_NODE_FUNCTION_MULTIARCH (ip4_mpls_label_imposition_pipe_no_ip_ttl_decr_node,
+                              ip4_mpls_label_imposition_pipe_no_ip_ttl_decr)
+
+static uword
+ip6_mpls_label_imposition_pipe_no_ip_ttl_decr (vlib_main_t * vm,
+                                               vlib_node_runtime_t * node,
+                                               vlib_frame_t * frame)
+{
+    return (mpls_label_imposition_inline(vm, node, frame,
+                                         DPO_PROTO_IP6,
+                                         MPLS_LABEL_DPO_FLAG_NO_IP_TTL_DECR));
+}
+
+VLIB_REGISTER_NODE (ip6_mpls_label_imposition_pipe_no_ip_ttl_decr_node) = {
+    .function = ip6_mpls_label_imposition_pipe_no_ip_ttl_decr,
+    .name = "ip6-mpls-label-imposition-pipe-no-ip-ttl-decr",
+    .vector_size = sizeof (u32),
+
+    .format_trace = format_mpls_label_imposition_trace,
+    .n_next_nodes = 1,
+    .next_nodes = {
+        [0] = "ip6-drop",
+    }
+};
+VLIB_NODE_FUNCTION_MULTIARCH (ip6_mpls_label_imposition_pipe_no_ip_ttl_decr_node,
+                              ip6_mpls_label_imposition_pipe_no_ip_ttl_decr)
+
+static uword
+ip4_mpls_label_imposition_uniform_no_ip_ttl_decr (vlib_main_t * vm,
+                                                  vlib_node_runtime_t * node,
+                                                  vlib_frame_t * frame)
+{
+    return (mpls_label_imposition_inline(vm, node, frame,
+                                         DPO_PROTO_IP4,
+                                         (MPLS_LABEL_DPO_FLAG_UNIFORM_MODE |
+                                          MPLS_LABEL_DPO_FLAG_NO_IP_TTL_DECR)));
+}
+
+VLIB_REGISTER_NODE (ip4_mpls_label_imposition_uniform_no_ip_ttl_decr_node) = {
+    .function = ip4_mpls_label_imposition_uniform_no_ip_ttl_decr,
+    .name = "ip4-mpls-label-imposition-uniform-no-ip-ttl-decr",
+    .vector_size = sizeof (u32),
+
+    .format_trace = format_mpls_label_imposition_trace,
+    .n_next_nodes = 1,
+    .next_nodes = {
+        [0] = "ip4-drop",
+    }
+};
+VLIB_NODE_FUNCTION_MULTIARCH (ip4_mpls_label_imposition_uniform_no_ip_ttl_decr_node,
+                              ip4_mpls_label_imposition_uniform_no_ip_ttl_decr)
+
+static uword
+ip6_mpls_label_imposition_uniform_no_ip_ttl_decr (vlib_main_t * vm,
+                                                  vlib_node_runtime_t * node,
+                                                  vlib_frame_t * frame)
+{
+    return (mpls_label_imposition_inline(vm, node, frame,
+                                         DPO_PROTO_IP6,
+                                         (MPLS_LABEL_DPO_FLAG_UNIFORM_MODE |
+                                          MPLS_LABEL_DPO_FLAG_NO_IP_TTL_DECR)));
+}
+
+VLIB_REGISTER_NODE (ip6_mpls_label_imposition_uniform_no_ip_ttl_decr_node) = {
+    .function = ip6_mpls_label_imposition_uniform_no_ip_ttl_decr,
+    .name = "ip6-mpls-label-imposition-uniform-no-ip-ttl-decr",
+    .vector_size = sizeof (u32),
+
+    .format_trace = format_mpls_label_imposition_trace,
+    .n_next_nodes = 1,
+    .next_nodes = {
+        [0] = "ip6-drop",
+    }
+};
+VLIB_NODE_FUNCTION_MULTIARCH (ip6_mpls_label_imposition_uniform_no_ip_ttl_decr_node,
+                              ip6_mpls_label_imposition_uniform_no_ip_ttl_decr)
+
 
 static void
 mpls_label_dpo_mem_show (void)
@@ -678,38 +1211,118 @@ const static dpo_vft_t mld_vft = {
     .dv_mem_show = mpls_label_dpo_mem_show,
 };
 
-const static char* const mpls_label_imp_ip4_nodes[] =
+const static char* const mpls_label_imp_pipe_ip4_nodes[] =
 {
-    "ip4-mpls-label-imposition",
+    "ip4-mpls-label-imposition-pipe",
     NULL,
 };
-const static char* const mpls_label_imp_ip6_nodes[] =
+const static char* const mpls_label_imp_pipe_ip6_nodes[] =
 {
-    "ip6-mpls-label-imposition",
+    "ip6-mpls-label-imposition-pipe",
     NULL,
 };
-const static char* const mpls_label_imp_mpls_nodes[] =
+const static char* const mpls_label_imp_pipe_mpls_nodes[] =
 {
-    "mpls-label-imposition",
+    "mpls-label-imposition-pipe",
     NULL,
 };
-const static char* const mpls_label_imp_ethernet_nodes[] =
+const static char* const mpls_label_imp_pipe_ethernet_nodes[] =
 {
-    "ethernet-mpls-label-imposition",
+    "ethernet-mpls-label-imposition-pipe",
     NULL,
 };
 
-const static char* const * const mpls_label_imp_nodes[DPO_PROTO_NUM] =
+const static char* const * const mpls_label_imp_pipe_nodes[DPO_PROTO_NUM] =
 {
-    [DPO_PROTO_IP4]  = mpls_label_imp_ip4_nodes,
-    [DPO_PROTO_IP6]  = mpls_label_imp_ip6_nodes,
-    [DPO_PROTO_MPLS] = mpls_label_imp_mpls_nodes,
-    [DPO_PROTO_ETHERNET] = mpls_label_imp_ethernet_nodes,
+    [DPO_PROTO_IP4]  = mpls_label_imp_pipe_ip4_nodes,
+    [DPO_PROTO_IP6]  = mpls_label_imp_pipe_ip6_nodes,
+    [DPO_PROTO_MPLS] = mpls_label_imp_pipe_mpls_nodes,
+    [DPO_PROTO_ETHERNET] = mpls_label_imp_pipe_ethernet_nodes,
 };
 
+const static char* const mpls_label_imp_uniform_ip4_nodes[] =
+{
+    "ip4-mpls-label-imposition-uniform",
+    NULL,
+};
+const static char* const mpls_label_imp_uniform_ip6_nodes[] =
+{
+    "ip6-mpls-label-imposition-uniform",
+    NULL,
+};
+const static char* const mpls_label_imp_uniform_mpls_nodes[] =
+{
+    "mpls-label-imposition-uniform",
+    NULL,
+};
+const static char* const mpls_label_imp_uniform_ethernet_nodes[] =
+{
+    "ethernet-mpls-label-imposition-uniform",
+    NULL,
+};
+
+const static char* const * const mpls_label_imp_uniform_nodes[DPO_PROTO_NUM] =
+{
+    [DPO_PROTO_IP4]  = mpls_label_imp_uniform_ip4_nodes,
+    [DPO_PROTO_IP6]  = mpls_label_imp_uniform_ip6_nodes,
+    [DPO_PROTO_MPLS] = mpls_label_imp_uniform_mpls_nodes,
+    [DPO_PROTO_ETHERNET] = mpls_label_imp_uniform_ethernet_nodes,
+};
+
+const static char* const mpls_label_imp_pipe_no_ip_tll_decr_ip4_nodes[] =
+{
+    "ip4-mpls-label-imposition-pipe-no-ip-ttl-decr",
+    NULL,
+};
+const static char* const mpls_label_imp_pipe_no_ip_tll_decr_ip6_nodes[] =
+{
+    "ip6-mpls-label-imposition-pipe-no-ip-ttl-decr",
+    NULL,
+};
+
+const static char* const * const mpls_label_imp_pipe_no_ip_tll_decr_nodes[DPO_PROTO_NUM] =
+{
+    [DPO_PROTO_IP4]  = mpls_label_imp_pipe_no_ip_tll_decr_ip4_nodes,
+    [DPO_PROTO_IP6]  = mpls_label_imp_pipe_no_ip_tll_decr_ip6_nodes,
+};
+
+const static char* const mpls_label_imp_uniform_no_ip_tll_decr_ip4_nodes[] =
+{
+    "ip4-mpls-label-imposition-uniform-no-ip-ttl-decr",
+    NULL,
+};
+const static char* const mpls_label_imp_uniform_no_ip_tll_decr_ip6_nodes[] =
+{
+    "ip6-mpls-label-imposition-uniform-no-ip-ttl-decr",
+    NULL,
+};
+
+const static char* const * const mpls_label_imp_uniform_no_ip_tll_decr_nodes[DPO_PROTO_NUM] =
+{
+    [DPO_PROTO_IP4]  = mpls_label_imp_uniform_no_ip_tll_decr_ip4_nodes,
+    [DPO_PROTO_IP6]  = mpls_label_imp_uniform_no_ip_tll_decr_ip6_nodes,
+};
 
 void
 mpls_label_dpo_module_init (void)
 {
-    dpo_register(DPO_MPLS_LABEL, &mld_vft, mpls_label_imp_nodes);
+    mpls_label_dpo_types[MPLS_LABEL_DPO_FLAG_NONE] =
+        dpo_register_new_type(&mld_vft,
+                              mpls_label_imp_pipe_nodes);
+    mpls_label_dpo_types[MPLS_LABEL_DPO_FLAG_NO_IP_TTL_DECR] =
+        dpo_register_new_type(&mld_vft,
+                              mpls_label_imp_pipe_no_ip_tll_decr_nodes);
+    mpls_label_dpo_types[MPLS_LABEL_DPO_FLAG_UNIFORM_MODE] =
+        dpo_register_new_type(&mld_vft,
+                              mpls_label_imp_uniform_nodes);
+    mpls_label_dpo_types[MPLS_LABEL_DPO_FLAG_UNIFORM_MODE |
+                         MPLS_LABEL_DPO_FLAG_NO_IP_TTL_DECR] =
+        dpo_register_new_type(&mld_vft,
+                              mpls_label_imp_uniform_no_ip_tll_decr_nodes);
+}
+
+dpo_type_t
+mpls_label_dpo_get_type (mpls_label_dpo_flags_t flags)
+{
+    return (mpls_label_dpo_types[flags]);
 }