Add support for set_mpls_ttl action

This adds support for the OpenFlow 1.1+ set_mpls_ttl action.
And also adds an NX set_mpls_ttl action.

The handling of the TTL modification is entirely handled in userspace.

Reviewed-by: Isaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Ben Pfaff <blp@nicira.com>

diff --git a/NEWS b/NEWS
index 1d67df8..7fb0932 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -7,8 +7,8 @@ post-v1.10.0
       protocol (RFC 6830).  An external control plane or manual flow
       setup is required for EID-to-RLOC mapping.
     - OpenFlow:
-      * The "dec_mpls_ttl" action from OpenFlow 1.1 and later is now
-        implemented.
+      * The "dec_mpls_ttl" and "set_mpls_ttl" actions from OpenFlow
+        1.1 and later are now implemented.
 
 
 v1.10.0 - xx xxx xxxx

diff --git a/include/openflow/nicira-ext.h b/include/openflow/nicira-ext.h
index db96be9..cdb1952 100644 (file)
--- a/include/openflow/nicira-ext.h
+++ b/include/openflow/nicira-ext.h
@@ -306,6 +306,7 @@ enum nx_action_subtype {
     NXAST_WRITE_METADATA,       /* struct nx_action_write_metadata */
     NXAST_PUSH_MPLS,            /* struct nx_action_push_mpls */
     NXAST_POP_MPLS,             /* struct nx_action_pop_mpls */
+    NXAST_SET_MPLS_TTL,         /* struct nx_action_ttl */
     NXAST_DEC_MPLS_TTL,         /* struct nx_action_header */
 };
 
@@ -2193,4 +2194,15 @@ struct nx_action_pop_mpls {
 };
 OFP_ASSERT(sizeof(struct nx_action_pop_mpls) == 16);
 
+/* Action structure for NXAST_SET_MPLS_TTL. */
+struct nx_action_mpls_ttl {
+    ovs_be16 type;                  /* OFPAT_VENDOR. */
+    ovs_be16 len;                   /* Length is 8. */
+    ovs_be32 vendor;                /* NX_VENDOR_ID. */
+    ovs_be16 subtype;               /* NXAST_SET_MPLS_TTL. */
+    uint8_t  ttl;                   /* TTL */
+    uint8_t  pad[5];
+};
+OFP_ASSERT(sizeof(struct nx_action_mpls_ttl) == 16);
+
 #endif /* openflow/nicira-ext.h */

diff --git a/lib/ofp-actions.c b/lib/ofp-actions.c
index 2b655dc..6dabc5a 100644 (file)
--- a/lib/ofp-actions.c
+++ b/lib/ofp-actions.c
@@ -406,6 +406,12 @@ ofpact_from_nxast(const union ofp_action *a, enum ofputil_action_code code,
         break;
     }
 
+    case OFPUTIL_NXAST_SET_MPLS_TTL: {
+        struct nx_action_mpls_ttl *nxamt = (struct nx_action_mpls_ttl *)a;
+        ofpact_put_SET_MPLS_TTL(out)->ttl = nxamt->ttl;
+        break;
+    }
+
     case OFPUTIL_NXAST_DEC_MPLS_TTL:
         ofpact_put_DEC_MPLS_TTL(out);
         break;
@@ -790,6 +796,12 @@ ofpact_from_openflow11(const union ofp_action *a, struct ofpbuf *out)
         return nxm_reg_load_from_openflow12_set_field(
             (const struct ofp12_action_set_field *)a, out);
 
+    case OFPUTIL_OFPAT11_SET_MPLS_TTL: {
+        struct ofp11_action_mpls_ttl *oamt = (struct ofp11_action_mpls_ttl *)a;
+        ofpact_put_SET_MPLS_TTL(out)->ttl = oamt->mpls_ttl;
+        break;
+    }
+
     case OFPUTIL_OFPAT11_DEC_MPLS_TTL:
         ofpact_put_DEC_MPLS_TTL(out);
         break;
@@ -1144,6 +1156,7 @@ ofpact_check__(const struct ofpact *a, const struct flow *flow, int max_ports,
         }
 
     case OFPACT_DEC_TTL:
+    case OFPACT_SET_MPLS_TTL:
     case OFPACT_DEC_MPLS_TTL:
     case OFPACT_SET_TUNNEL:
     case OFPACT_SET_QUEUE:
@@ -1392,6 +1405,11 @@ ofpact_to_nxast(const struct ofpact *a, struct ofpbuf *out)
         ofpact_dec_ttl_to_nxast(ofpact_get_DEC_TTL(a), out);
         break;
 
+    case OFPACT_SET_MPLS_TTL:
+        ofputil_put_NXAST_SET_MPLS_TTL(out)->ttl
+            = ofpact_get_SET_MPLS_TTL(a)->ttl;
+        break;
+
     case OFPACT_DEC_MPLS_TTL:
         ofputil_put_NXAST_DEC_MPLS_TTL(out);
         break;
@@ -1563,6 +1581,7 @@ ofpact_to_openflow10(const struct ofpact *a, struct ofpbuf *out)
     case OFPACT_REG_MOVE:
     case OFPACT_REG_LOAD:
     case OFPACT_DEC_TTL:
+    case OFPACT_SET_MPLS_TTL:
     case OFPACT_DEC_MPLS_TTL:
     case OFPACT_SET_TUNNEL:
     case OFPACT_WRITE_METADATA:
@@ -1696,6 +1715,11 @@ ofpact_to_openflow11(const struct ofpact *a, struct ofpbuf *out)
         ofpact_dec_ttl_to_openflow11(ofpact_get_DEC_TTL(a), out);
         break;
 
+    case OFPACT_SET_MPLS_TTL:
+        ofputil_put_OFPAT11_SET_MPLS_TTL(out)->mpls_ttl
+            = ofpact_get_SET_MPLS_TTL(a)->ttl;
+        break;
+
     case OFPACT_DEC_MPLS_TTL:
         ofputil_put_OFPAT11_DEC_MPLS_TTL(out);
         break;
@@ -1844,6 +1868,7 @@ ofpact_outputs_to_port(const struct ofpact *ofpact, uint16_t port)
     case OFPACT_REG_MOVE:
     case OFPACT_REG_LOAD:
     case OFPACT_DEC_TTL:
+    case OFPACT_SET_MPLS_TTL:
     case OFPACT_DEC_MPLS_TTL:
     case OFPACT_SET_TUNNEL:
     case OFPACT_WRITE_METADATA:
@@ -2067,6 +2092,11 @@ ofpact_format(const struct ofpact *a, struct ds *s)
         print_dec_ttl(ofpact_get_DEC_TTL(a), s);
         break;
 
+    case OFPACT_SET_MPLS_TTL:
+        ds_put_format(s, "set_mpls_ttl(%"PRIu8")",
+                      ofpact_get_SET_MPLS_TTL(a)->ttl);
+        break;
+
     case OFPACT_DEC_MPLS_TTL:
         ds_put_cstr(s, "dec_mpls_ttl");
         break;

diff --git a/lib/ofp-actions.h b/lib/ofp-actions.h
index 5746a5a..2d934f9 100644 (file)
--- a/lib/ofp-actions.h
+++ b/lib/ofp-actions.h
@@ -71,6 +71,7 @@
     DEFINE_OFPACT(REG_MOVE,        ofpact_reg_move,      ofpact)    \
     DEFINE_OFPACT(REG_LOAD,        ofpact_reg_load,      ofpact)    \
     DEFINE_OFPACT(DEC_TTL,         ofpact_cnt_ids,       cnt_ids)   \
+    DEFINE_OFPACT(SET_MPLS_TTL,    ofpact_mpls_ttl,      ofpact)    \
     DEFINE_OFPACT(DEC_MPLS_TTL,    ofpact_null,          ofpact)    \
     DEFINE_OFPACT(PUSH_MPLS,       ofpact_push_mpls,     ofpact)    \
     DEFINE_OFPACT(POP_MPLS,        ofpact_pop_mpls,      ofpact)    \
@@ -441,6 +442,15 @@ struct ofpact_cnt_ids {
     uint16_t cnt_ids[];
 };
 
+/* OFPACT_SET_MPLS_TTL.
+ *
+ * Used for NXAST_SET_MPLS_TTL */
+struct ofpact_mpls_ttl {
+    struct ofpact ofpact;
+
+    uint8_t ttl;
+};
+
 /* OFPACT_GOTO_TABLE
  *
  * Used for OFPIT11_GOTO_TABLE */

diff --git a/lib/ofp-parse.c b/lib/ofp-parse.c
index 7b881af..f180204 100644 (file)
--- a/lib/ofp-parse.c
+++ b/lib/ofp-parse.c
@@ -317,6 +317,18 @@ parse_dec_ttl(struct ofpbuf *b, char *arg)
     }
 }
 
+static void
+parse_set_mpls_ttl(struct ofpbuf *b, const char *arg)
+{
+    struct ofpact_mpls_ttl *mpls_ttl = ofpact_put_SET_MPLS_TTL(b);
+
+    if (*arg == '\0') {
+        ovs_fatal(0, "parse_set_mpls_ttl: expected ttl.");
+    }
+
+    mpls_ttl->ttl = atoi(arg);
+}
+
 static void
 set_field_parse(const char *arg, struct ofpbuf *ofpacts)
 {
@@ -550,6 +562,11 @@ parse_named_action(enum ofputil_action_code code, const struct flow *flow,
         parse_dec_ttl(ofpacts, arg);
         break;
 
+    case OFPUTIL_NXAST_SET_MPLS_TTL:
+    case OFPUTIL_OFPAT11_SET_MPLS_TTL:
+        parse_set_mpls_ttl(ofpacts, arg);
+        break;
+
     case OFPUTIL_OFPAT11_DEC_MPLS_TTL:
     case OFPUTIL_NXAST_DEC_MPLS_TTL:
         ofpact_put_DEC_MPLS_TTL(ofpacts);

diff --git a/lib/ofp-util.def b/lib/ofp-util.def
index d55b1eb..439d34e 100644 (file)
--- a/lib/ofp-util.def
+++ b/lib/ofp-util.def
@@ -30,6 +30,7 @@ OFPAT11_ACTION(OFPAT11_SET_NW_TOS,   ofp_action_nw_tos,   0, "mod_nw_tos")
 //OFPAT11_ACTION(OFPAT11_SET_NW_ECN,   ofp11_action_nw_ecn, "0, mod_nw_ecn")
 OFPAT11_ACTION(OFPAT11_SET_TP_SRC,   ofp_action_tp_port,  0, "mod_tp_src")
 OFPAT11_ACTION(OFPAT11_SET_TP_DST,   ofp_action_tp_port,  0, "mod_tp_dst")
+OFPAT11_ACTION(OFPAT11_SET_MPLS_TTL, ofp11_action_mpls_ttl, 0, "set_mpls_ttl")
 OFPAT11_ACTION(OFPAT11_DEC_MPLS_TTL, ofp_action_header,   0, "dec_mpls_ttl")
 OFPAT11_ACTION(OFPAT11_PUSH_VLAN,    ofp11_action_push,   0, "push_vlan")
 OFPAT11_ACTION(OFPAT11_POP_VLAN,     ofp_action_header,   0, "pop_vlan")
@@ -64,6 +65,7 @@ NXAST_ACTION(NXAST_CONTROLLER,      nx_action_controller,   0, "controller")
 NXAST_ACTION(NXAST_DEC_TTL_CNT_IDS, nx_action_cnt_ids,      1, NULL)
 NXAST_ACTION(NXAST_WRITE_METADATA,  nx_action_write_metadata, 0,
              "write_metadata")
+NXAST_ACTION(NXAST_SET_MPLS_TTL,    nx_action_mpls_ttl,     0, "set_mpls_ttl")
 NXAST_ACTION(NXAST_DEC_MPLS_TTL,    nx_action_header,       0, "dec_mpls_ttl")
 NXAST_ACTION(NXAST_PUSH_MPLS,       nx_action_push_mpls,    0, "push_mpls")
 NXAST_ACTION(NXAST_POP_MPLS,        nx_action_pop_mpls,     0, "pop_mpls")

diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c
index ea6104a..ff7f653 100644 (file)
--- a/ofproto/ofproto-dpif.c
+++ b/ofproto/ofproto-dpif.c
@@ -6058,6 +6058,17 @@ compose_dec_ttl(struct action_xlate_ctx *ctx, struct ofpact_cnt_ids *ids)
     }
 }
 
+static bool
+execute_set_mpls_ttl_action(struct action_xlate_ctx *ctx, uint8_t ttl)
+{
+    if (!eth_type_mpls(ctx->flow.dl_type)) {
+        return true;
+    }
+
+    set_mpls_lse_ttl(&ctx->flow.mpls_lse, ttl);
+    return false;
+}
+
 static bool
 execute_dec_mpls_ttl_action(struct action_xlate_ctx *ctx)
 {
@@ -6422,6 +6433,12 @@ do_xlate_actions(const struct ofpact *ofpacts, size_t ofpacts_len,
             execute_mpls_pop_action(ctx, ofpact_get_POP_MPLS(a)->ethertype);
             break;
 
+        case OFPACT_SET_MPLS_TTL:
+            if (execute_set_mpls_ttl_action(ctx, ofpact_get_SET_MPLS_TTL(a)->ttl)) {
+                goto out;
+            }
+            break;
+
         case OFPACT_DEC_MPLS_TTL:
             if (execute_dec_mpls_ttl_action(ctx)) {
                 goto out;

diff --git a/tests/ofproto-dpif.at b/tests/ofproto-dpif.at
index cd08e29..b795f56 100644 (file)
--- a/tests/ofproto-dpif.at
+++ b/tests/ofproto-dpif.at
@@ -234,6 +234,9 @@ cookie=0xa dl_src=40:44:44:44:44:42 actions=push_mpls:0x8847,load:10->OXM_OF_MPL
 cookie=0xa dl_src=40:44:44:44:44:43 actions=push_mpls:0x8847,load:10->OXM_OF_MPLS_LABEL[[]],load:3->OXM_OF_MPLS_TC[[]],controller
 cookie=0xa dl_src=40:44:44:44:44:44 actions=push_mpls:0x8847,load:10->OXM_OF_MPLS_LABEL[[]],load:3->OXM_OF_MPLS_TC[[]],controller
 cookie=0xa dl_src=40:44:44:44:44:45 actions=push_mpls:0x8847,load:10->OXM_OF_MPLS_LABEL[[]],load:3->OXM_OF_MPLS_TC[[]],dec_mpls_ttl,controller
+cookie=0xa dl_src=40:44:44:44:44:46 actions=push_mpls:0x8847,load:10->OXM_OF_MPLS_LABEL[[]],load:3->OXM_OF_MPLS_TC[[]],set_mpls_ttl(10),controller
+cookie=0xa dl_src=40:44:44:44:44:47 actions=push_mpls:0x8847,load:10->OXM_OF_MPLS_LABEL[[]],load:3->OXM_OF_MPLS_TC[[]],dec_mpls_ttl,set_mpls_ttl(10),controller
+cookie=0xa dl_src=40:44:44:44:44:48 actions=push_mpls:0x8847,load:10->OXM_OF_MPLS_LABEL[[]],load:3->OXM_OF_MPLS_TC[[]],set_mpls_ttl(10),dec_mpls_ttl,controller
 cookie=0xb dl_src=50:55:55:55:55:55 dl_type=0x8847 actions=load:1000->OXM_OF_MPLS_LABEL[[]],controller
 cookie=0xd dl_src=60:66:66:66:66:66 actions=pop_mpls:0x0800,controller
 cookie=0xc dl_src=70:77:77:77:77:77 actions=push_mpls:0x8848,load:1000->OXM_OF_MPLS_LABEL[[]],load:7->OXM_OF_MPLS_TC[[]],controller
@@ -375,6 +378,63 @@ NXT_PACKET_IN (xid=0x0): cookie=0xa total_len=64 in_port=1 (via action) data_len
 mpls(label:10,tc:3,ttl:63,bos:1),metadata=0,in_port=0,vlan_tci=0x0000,dl_src=40:44:44:44:44:45,dl_dst=50:54:00:00:00:07
 ])
 
+dnl Modified MPLS controller action.
+AT_CHECK([ovs-ofctl monitor br0 65534 -P nxm --detach --pidfile 2> ofctl_monitor.log])
+
+for i in 1 2 3; do
+    ovs-appctl netdev-dummy/receive p1 'in_port(1),eth(src=40:44:44:44:44:46,dst=50:54:00:00:00:07),eth_type(0x0800),ipv4(src=192.168.0.1,dst=192.168.0.2,proto=6,tos=0,ttl=64,frag=no)'
+done
+
+OVS_WAIT_UNTIL([ovs-appctl -t ovs-ofctl exit])
+AT_CHECK([cat ofctl_monitor.log], [0], [dnl
+NXT_PACKET_IN (xid=0x0): cookie=0xa total_len=64 in_port=1 (via action) data_len=64 (unbuffered)
+mpls(label:10,tc:3,ttl:10,bos:1),metadata=0,in_port=0,vlan_tci=0x0000,dl_src=40:44:44:44:44:46,dl_dst=50:54:00:00:00:07
+dnl
+NXT_PACKET_IN (xid=0x0): cookie=0xa total_len=64 in_port=1 (via action) data_len=64 (unbuffered)
+mpls(label:10,tc:3,ttl:10,bos:1),metadata=0,in_port=0,vlan_tci=0x0000,dl_src=40:44:44:44:44:46,dl_dst=50:54:00:00:00:07
+dnl
+NXT_PACKET_IN (xid=0x0): cookie=0xa total_len=64 in_port=1 (via action) data_len=64 (unbuffered)
+mpls(label:10,tc:3,ttl:10,bos:1),metadata=0,in_port=0,vlan_tci=0x0000,dl_src=40:44:44:44:44:46,dl_dst=50:54:00:00:00:07
+])
+
+dnl Modified MPLS controller action.
+AT_CHECK([ovs-ofctl monitor br0 65534 -P nxm --detach --pidfile 2> ofctl_monitor.log])
+
+for i in 1 2 3; do
+    ovs-appctl netdev-dummy/receive p1 'in_port(1),eth(src=40:44:44:44:44:47,dst=50:54:00:00:00:07),eth_type(0x0800),ipv4(src=192.168.0.1,dst=192.168.0.2,proto=6,tos=0,ttl=64,frag=no)'
+done
+
+OVS_WAIT_UNTIL([ovs-appctl -t ovs-ofctl exit])
+AT_CHECK([cat ofctl_monitor.log], [0], [dnl
+NXT_PACKET_IN (xid=0x0): cookie=0xa total_len=64 in_port=1 (via action) data_len=64 (unbuffered)
+mpls(label:10,tc:3,ttl:10,bos:1),metadata=0,in_port=0,vlan_tci=0x0000,dl_src=40:44:44:44:44:47,dl_dst=50:54:00:00:00:07
+dnl
+NXT_PACKET_IN (xid=0x0): cookie=0xa total_len=64 in_port=1 (via action) data_len=64 (unbuffered)
+mpls(label:10,tc:3,ttl:10,bos:1),metadata=0,in_port=0,vlan_tci=0x0000,dl_src=40:44:44:44:44:47,dl_dst=50:54:00:00:00:07
+dnl
+NXT_PACKET_IN (xid=0x0): cookie=0xa total_len=64 in_port=1 (via action) data_len=64 (unbuffered)
+mpls(label:10,tc:3,ttl:10,bos:1),metadata=0,in_port=0,vlan_tci=0x0000,dl_src=40:44:44:44:44:47,dl_dst=50:54:00:00:00:07
+])
+
+dnl Modified MPLS controller action.
+AT_CHECK([ovs-ofctl monitor br0 65534 -P nxm --detach --pidfile 2> ofctl_monitor.log])
+
+for i in 1 2 3; do
+    ovs-appctl netdev-dummy/receive p1 'in_port(1),eth(src=40:44:44:44:44:48,dst=50:54:00:00:00:07),eth_type(0x0800),ipv4(src=192.168.0.1,dst=192.168.0.2,proto=6,tos=0,ttl=64,frag=no)'
+done
+
+OVS_WAIT_UNTIL([ovs-appctl -t ovs-ofctl exit])
+AT_CHECK([cat ofctl_monitor.log], [0], [dnl
+NXT_PACKET_IN (xid=0x0): cookie=0xa total_len=64 in_port=1 (via action) data_len=64 (unbuffered)
+mpls(label:10,tc:3,ttl:9,bos:1),metadata=0,in_port=0,vlan_tci=0x0000,dl_src=40:44:44:44:44:48,dl_dst=50:54:00:00:00:07
+dnl
+NXT_PACKET_IN (xid=0x0): cookie=0xa total_len=64 in_port=1 (via action) data_len=64 (unbuffered)
+mpls(label:10,tc:3,ttl:9,bos:1),metadata=0,in_port=0,vlan_tci=0x0000,dl_src=40:44:44:44:44:48,dl_dst=50:54:00:00:00:07
+dnl
+NXT_PACKET_IN (xid=0x0): cookie=0xa total_len=64 in_port=1 (via action) data_len=64 (unbuffered)
+mpls(label:10,tc:3,ttl:9,bos:1),metadata=0,in_port=0,vlan_tci=0x0000,dl_src=40:44:44:44:44:48,dl_dst=50:54:00:00:00:07
+])
+
 dnl Modified MPLS actions.
 AT_CHECK([ovs-ofctl monitor br0 65534 -P nxm --detach --pidfile 2> ofctl_monitor.log])
 
@@ -521,6 +581,9 @@ AT_CHECK([ovs-ofctl dump-flows br0 | ofctl_strip | sort], [0], [dnl
  cookie=0xa, n_packets=3, n_bytes=180, dl_src=40:44:44:44:44:43 actions=push_mpls:0x8847,load:0xa->OXM_OF_MPLS_LABEL[[]],load:0x3->OXM_OF_MPLS_TC[[]],CONTROLLER:65535
  cookie=0xa, n_packets=3, n_bytes=180, dl_src=40:44:44:44:44:44 actions=push_mpls:0x8847,load:0xa->OXM_OF_MPLS_LABEL[[]],load:0x3->OXM_OF_MPLS_TC[[]],CONTROLLER:65535
  cookie=0xa, n_packets=3, n_bytes=180, dl_src=40:44:44:44:44:45 actions=push_mpls:0x8847,load:0xa->OXM_OF_MPLS_LABEL[[]],load:0x3->OXM_OF_MPLS_TC[[]],dec_mpls_ttl,CONTROLLER:65535
+ cookie=0xa, n_packets=3, n_bytes=180, dl_src=40:44:44:44:44:46 actions=push_mpls:0x8847,load:0xa->OXM_OF_MPLS_LABEL[[]],load:0x3->OXM_OF_MPLS_TC[[]],set_mpls_ttl(10),CONTROLLER:65535
+ cookie=0xa, n_packets=3, n_bytes=180, dl_src=40:44:44:44:44:47 actions=push_mpls:0x8847,load:0xa->OXM_OF_MPLS_LABEL[[]],load:0x3->OXM_OF_MPLS_TC[[]],dec_mpls_ttl,set_mpls_ttl(10),CONTROLLER:65535
+ cookie=0xa, n_packets=3, n_bytes=180, dl_src=40:44:44:44:44:48 actions=push_mpls:0x8847,load:0xa->OXM_OF_MPLS_LABEL[[]],load:0x3->OXM_OF_MPLS_TC[[]],set_mpls_ttl(10),dec_mpls_ttl,CONTROLLER:65535
  cookie=0xb, n_packets=3, n_bytes=180, dl_src=50:55:55:55:55:55,dl_type=0x8847 actions=load:0x3e8->OXM_OF_MPLS_LABEL[[]],CONTROLLER:65535
  cookie=0xc, n_packets=3, n_bytes=180, dl_src=70:77:77:77:77:77 actions=push_mpls:0x8848,load:0x3e8->OXM_OF_MPLS_LABEL[[]],load:0x7->OXM_OF_MPLS_TC[[]],CONTROLLER:65535
  cookie=0xd, n_packets=3, n_bytes=180, dl_src=60:66:66:66:66:66 actions=pop_mpls:0x0800,CONTROLLER:65535

diff --git a/utilities/ovs-ofctl.8.in b/utilities/ovs-ofctl.8.in
index 40869c4..609df9f 100644 (file)
--- a/utilities/ovs-ofctl.8.in
+++ b/utilities/ovs-ofctl.8.in
@@ -1018,6 +1018,10 @@ invalid ttl packets.  If controller ids are not specified, the
 ``packet_in'' message will be sent only to the controllers having
 controller id zero which have registered for the invalid ttl packets.
 .
+.IP \fBset_mpls_ttl\fR:\fIttl\fR
+Set the TTL of the outer MPLS label stack entry of a packet.
+\fIttl\fR should be in the range 0 to 255 inclusive.
+.
 .IP \fBdec_mpls_ttl\fR
 Decrement TTL of the outer MPLS label stack entry of a packet.  If the TTL
 is initially zero, no decrement occurs.  Instead, a ``packet-in'' message