[ovs-dev] [PATCH v9 3/3] nsh: add dec_nsh_ttl action

Yi Yang yi.y.yang at intel.com
Thu Jan 11 05:24:03 UTC 2018


NSH ttl is a 6-bit field ranged from 0 to 63, it should be
decremented by 1 every hop, if it is 0 or it is so after
decremented, the packet should be dropped and a packet-in
message is sent to main controller.

Signed-off-by: Yi Yang <yi.y.yang at intel.com>
---
 NEWS                              |  1 +
 include/openvswitch/ofp-actions.h |  1 +
 lib/ofp-actions.c                 | 49 +++++++++++++++++++++++++++++++++++++++
 ofproto/ofproto-dpif-xlate.c      | 31 +++++++++++++++++++++++++
 tests/nsh.at                      |  6 ++---
 utilities/ovs-ofctl.8.in          | 13 ++++++++++-
 6 files changed, 97 insertions(+), 4 deletions(-)

diff --git a/NEWS b/NEWS
index ae684e3..1a0253c 100644
--- a/NEWS
+++ b/NEWS
@@ -2,6 +2,7 @@ Post-v2.8.0
 --------------------
    - NSH implementation now conforms to latest draft (draft-ietf-sfc-nsh-28).
      * Add ttl field.
+     * Add a new action dec_nsh_ttl.
    - OVSDB:
      * New high-level documentation in ovsdb(7).
      * New file format documentation for developers in ovsdb(5).
diff --git a/include/openvswitch/ofp-actions.h b/include/openvswitch/ofp-actions.h
index 3d97755..c82dae0 100644
--- a/include/openvswitch/ofp-actions.h
+++ b/include/openvswitch/ofp-actions.h
@@ -93,6 +93,7 @@ struct vl_mff_map;
     OFPACT(DEC_MPLS_TTL,    ofpact_null,        ofpact, "dec_mpls_ttl") \
     OFPACT(PUSH_MPLS,       ofpact_push_mpls,   ofpact, "push_mpls")    \
     OFPACT(POP_MPLS,        ofpact_pop_mpls,    ofpact, "pop_mpls")     \
+    OFPACT(DEC_NSH_TTL,     ofpact_null,        ofpact, "dec_nsh_ttl")  \
                                                                         \
     /* Generic encap & decap */                                         \
     OFPACT(ENCAP,           ofpact_encap,       props, "encap")         \
diff --git a/lib/ofp-actions.c b/lib/ofp-actions.c
index 4918498..7acf05f 100644
--- a/lib/ofp-actions.c
+++ b/lib/ofp-actions.c
@@ -350,6 +350,9 @@ enum ofp_raw_action_type {
     /* NX1.3+(47): struct nx_action_decap, ... */
     NXAST_RAW_DECAP,
 
+    /* NX1.3+(48): void. */
+    NXAST_RAW_DEC_NSH_TTL,
+
 /* ## ------------------ ## */
 /* ## Debugging actions. ## */
 /* ## ------------------ ## */
@@ -482,6 +485,7 @@ ofpact_next_flattened(const struct ofpact *ofpact)
     case OFPACT_NAT:
     case OFPACT_ENCAP:
     case OFPACT_DECAP:
+    case OFPACT_DEC_NSH_TTL:
         return ofpact_next(ofpact);
 
     case OFPACT_CLONE:
@@ -4332,6 +4336,39 @@ format_DECAP(const struct ofpact_decap *a,
     ds_put_format(s, "%s)%s", colors.paren, colors.end);
 }
 
+/* Action dec_nsh_ttl */
+
+static enum ofperr
+decode_NXAST_RAW_DEC_NSH_TTL(struct ofpbuf *out)
+{
+    ofpact_put_DEC_NSH_TTL(out);
+    return 0;
+}
+
+static void
+encode_DEC_NSH_TTL(const struct ofpact_null *null OVS_UNUSED,
+            enum ofp_version ofp_version OVS_UNUSED, struct ofpbuf *out)
+{
+    put_NXAST_DEC_NSH_TTL(out);
+}
+
+static char * OVS_WARN_UNUSED_RESULT
+parse_DEC_NSH_TTL(char *arg OVS_UNUSED,
+           const struct ofputil_port_map *port_map OVS_UNUSED,
+           struct ofpbuf *ofpacts,
+           enum ofputil_protocol *usable_protocols OVS_UNUSED)
+{
+    ofpact_put_DEC_NSH_TTL(ofpacts);
+    return NULL;
+}
+
+static void
+format_DEC_NSH_TTL(const struct ofpact_null *a OVS_UNUSED,
+            const struct ofputil_port_map *port_map OVS_UNUSED, struct ds *s)
+{
+    ds_put_format(s, "%sdec_nsh_ttl%s", colors.special, colors.end);
+}
+
 
 /* Action structures for NXAST_RESUBMIT, NXAST_RESUBMIT_TABLE, and
  * NXAST_RESUBMIT_TABLE_CT.
@@ -7115,6 +7152,7 @@ ofpact_is_set_or_move_action(const struct ofpact *a)
     case OFPACT_SET_VLAN_VID:
     case OFPACT_ENCAP:
     case OFPACT_DECAP:
+    case OFPACT_DEC_NSH_TTL:
         return true;
     case OFPACT_BUNDLE:
     case OFPACT_CLEAR_ACTIONS:
@@ -7192,6 +7230,7 @@ ofpact_is_allowed_in_actions_set(const struct ofpact *a)
     case OFPACT_STRIP_VLAN:
     case OFPACT_ENCAP:
     case OFPACT_DECAP:
+    case OFPACT_DEC_NSH_TTL:
         return true;
 
     /* In general these actions are excluded because they are not part of
@@ -7305,6 +7344,7 @@ ofpacts_execute_action_set(struct ofpbuf *action_list,
     ofpacts_copy_last(action_list, action_set, OFPACT_PUSH_VLAN);
     ofpacts_copy_last(action_list, action_set, OFPACT_DEC_TTL);
     ofpacts_copy_last(action_list, action_set, OFPACT_DEC_MPLS_TTL);
+    ofpacts_copy_last(action_list, action_set, OFPACT_DEC_NSH_TTL);
     ofpacts_copy_all(action_list, action_set, ofpact_is_set_or_move_action);
     ofpacts_copy_last(action_list, action_set, OFPACT_SET_QUEUE);
 
@@ -7446,6 +7486,7 @@ ovs_instruction_type_from_ofpact_type(enum ofpact_type type)
     case OFPACT_NAT:
     case OFPACT_ENCAP:
     case OFPACT_DECAP:
+    case OFPACT_DEC_NSH_TTL:
     default:
         return OVSINST_OFPIT11_APPLY_ACTIONS;
     }
@@ -8132,6 +8173,13 @@ ofpact_check__(enum ofputil_protocol *usable_protocols, struct ofpact *a,
         }
         return 0;
 
+    case OFPACT_DEC_NSH_TTL:
+        if ((flow->packet_type != htonl(PT_NSH)) &&
+            (flow->dl_type != htons(ETH_TYPE_NSH))) {
+            inconsistent_match(usable_protocols);
+        }
+        return 0;
+
     default:
         OVS_NOT_REACHED();
     }
@@ -8627,6 +8675,7 @@ ofpact_outputs_to_port(const struct ofpact *ofpact, ofp_port_t port)
     case OFPACT_NAT:
     case OFPACT_ENCAP:
     case OFPACT_DECAP:
+    case OFPACT_DEC_NSH_TTL:
     default:
         return false;
     }
diff --git a/ofproto/ofproto-dpif-xlate.c b/ofproto/ofproto-dpif-xlate.c
index 2f0a19c..adab37b 100644
--- a/ofproto/ofproto-dpif-xlate.c
+++ b/ofproto/ofproto-dpif-xlate.c
@@ -4811,6 +4811,28 @@ compose_set_mpls_tc_action(struct xlate_ctx *ctx, uint8_t tc)
     }
 }
 
+static bool
+compose_dec_nsh_ttl_action(struct xlate_ctx *ctx)
+{
+    struct flow *flow = &ctx->xin->flow;
+
+    if ((flow->packet_type == htonl(PT_NSH)) ||
+        (flow->dl_type == htons(ETH_TYPE_NSH))) {
+        ctx->wc->masks.nsh.ttl = 0xff;
+        if (flow->nsh.ttl > 1) {
+            flow->nsh.ttl--;
+            return false;
+        } else {
+            execute_controller_action(ctx, UINT16_MAX, OFPR_INVALID_TTL, 0,
+                                      NULL, 0);
+        }
+    }
+
+    /* Stop processing for current table. */
+    xlate_report(ctx, OFT_WARN, "NSH decrement TTL exception");
+    return true;
+}
+
 static void
 compose_set_mpls_ttl_action(struct xlate_ctx *ctx, uint8_t ttl)
 {
@@ -5358,6 +5380,7 @@ reversible_actions(const struct ofpact *ofpacts, size_t ofpacts_len)
         case OFPACT_OUTPUT_TRUNC:
         case OFPACT_ENCAP:
         case OFPACT_DECAP:
+        case OFPACT_DEC_NSH_TTL:
             return false;
         }
     }
@@ -5585,6 +5608,7 @@ freeze_unroll_actions(const struct ofpact *a, const struct ofpact *end,
         case OFPACT_OUTPUT:
         case OFPACT_CONTROLLER:
         case OFPACT_DEC_MPLS_TTL:
+        case OFPACT_DEC_NSH_TTL:
         case OFPACT_DEC_TTL:
             /* These actions may generate asynchronous messages, which include
              * table ID and flow cookie information. */
@@ -6132,6 +6156,7 @@ recirc_for_mpls(const struct ofpact *a, struct xlate_ctx *ctx)
     case OFPACT_CLONE:
     case OFPACT_ENCAP:
     case OFPACT_DECAP:
+    case OFPACT_DEC_NSH_TTL:
     case OFPACT_UNROLL_XLATE:
     case OFPACT_CT:
     case OFPACT_CT_CLEAR:
@@ -6457,6 +6482,12 @@ do_xlate_actions(const struct ofpact *ofpacts, size_t ofpacts_len,
             }
             break;
 
+        case OFPACT_DEC_NSH_TTL:
+            if (compose_dec_nsh_ttl_action(ctx)) {
+                return;
+            }
+            break;
+
         case OFPACT_DEC_TTL:
             wc->masks.nw_ttl = 0xff;
             if (compose_dec_ttl(ctx, ofpact_get_DEC_TTL(a))) {
diff --git a/tests/nsh.at b/tests/nsh.at
index 6177cea..e6a8345 100644
--- a/tests/nsh.at
+++ b/tests/nsh.at
@@ -542,7 +542,7 @@ AT_DATA([br-in2.txt], [dnl
     table=2,packet_type=(1,0x894f),nsh_spi=0x1020,nsh_si=255,actions=encap(ethernet),set_field:77:88:99:aa:bb:cc->dl_dst,goto_table:4
     table=2,packet_type=(1,0x894f),nsh_spi=0x1020,nsh_si=254,actions=output:2010
     table=4,dl_type=0x894f,dl_dst=11:22:33:44:55:66,actions=set_field:254->nsh_si,decap(),resubmit(,2)
-    table=4,dl_type=0x894f,dl_dst=77:88:99:aa:bb:cc,actions=set_field:254->nsh_si,decap(),resubmit(,2)
+    table=4,dl_type=0x894f,dl_dst=77:88:99:aa:bb:cc,actions=dec_nsh_ttl,decap(),resubmit(,2)
 ])
 
 # br-in3 is SFC classifier (table 1) and final SFF (tables 2,3)
@@ -607,7 +607,7 @@ AT_CHECK([
  table=2, packet_type=(1,0x894f),nsh_spi=0x3020,nsh_si=254 actions=output:2030
  table=2, packet_type=(1,0x894f),nsh_spi=0x3020,nsh_si=255 actions=encap(ethernet),set_field:11:22:33:44:55:66->eth_dst,goto_table:4
  table=4, dl_dst=11:22:33:44:55:66,dl_type=0x894f actions=set_field:254->nsh_si,decap(),resubmit(,2)
- table=4, dl_dst=77:88:99:aa:bb:cc,dl_type=0x894f actions=set_field:254->nsh_si,decap(),resubmit(,2)
+ table=4, dl_dst=77:88:99:aa:bb:cc,dl_type=0x894f actions=dec_nsh_ttl,decap(),resubmit(,2)
  ip,in_port=30 actions=decap(),goto_table:1
  n_packets=2, n_bytes=216, packet_type=(1,0x894f),in_port=3010 actions=goto_table:2
  packet_type=(1,0x800),in_port=30 actions=goto_table:1
@@ -661,7 +661,7 @@ AT_CHECK([
  table=2, n_packets=2, n_bytes=216, packet_type=(1,0x894f),nsh_spi=0x3020,nsh_si=255 actions=encap(ethernet),set_field:11:22:33:44:55:66->eth_dst,goto_table:4
  table=2, packet_type=(1,0x894f),nsh_spi=0x1020,nsh_si=254 actions=output:2010
  table=2, packet_type=(1,0x894f),nsh_spi=0x1020,nsh_si=255 actions=encap(ethernet),set_field:77:88:99:aa:bb:cc->eth_dst,goto_table:4
- table=4, dl_dst=77:88:99:aa:bb:cc,dl_type=0x894f actions=set_field:254->nsh_si,decap(),resubmit(,2)
+ table=4, dl_dst=77:88:99:aa:bb:cc,dl_type=0x894f actions=dec_nsh_ttl,decap(),resubmit(,2)
  table=4, n_packets=2, n_bytes=216, dl_dst=11:22:33:44:55:66,dl_type=0x894f actions=set_field:254->nsh_si,decap(),resubmit(,2)
  ip,in_port=30 actions=decap(),goto_table:1
  n_packets=2, n_bytes=216, packet_type=(1,0x894f),in_port=3010 actions=goto_table:2
diff --git a/utilities/ovs-ofctl.8.in b/utilities/ovs-ofctl.8.in
index 5cdf48c..95344c7 100644
--- a/utilities/ovs-ofctl.8.in
+++ b/utilities/ovs-ofctl.8.in
@@ -1280,6 +1280,15 @@ Processing the current set of actions then stops.  However, if the current
 set of actions was reached through ``resubmit'' then remaining actions in
 outer levels resume processing.
 .
+.IP \fBdec_nsh_ttl\fR
+Decrement TTL of the outer NSH header of a packet.  If the TTL
+is initially zero or decrementing would make it so, no decrement occurs.
+Instead, a ``packet-in'' message with reason code \fBOFPR_INVALID_TTL\fR
+is sent to the main controller (id zero), if it has enabled receiving them.
+Processing the current set of actions then stops.  However, if the current
+set of actions was reached through ``resubmit'' then remaining actions in
+outer levels resume processing.
+.
 .IP \fBnote:\fR[\fIhh\fR]...
 Does nothing at all.  Any number of bytes represented as hex digits
 \fIhh\fR may be included.  Pairs of hex digits may be separated by
@@ -1587,6 +1596,8 @@ the action set, the one written later replaces the earlier action:
 \fBdec_ttl\fR
 .IQ
 \fBdec_mpls_ttl\fR
+.IQ
+\fBdec_nsh_ttl\fR
 .
 .IP 7.
 \fBload\fR
@@ -1647,7 +1658,7 @@ not visible.)
 .RE
 .IP
 Only the actions listed above may be written to the action set.
-\fBencap\fR and \fBdecap\fR actions are nonstandard.
+\fBencap\fR, \fBdecap\fR and \fBdec_nsh_ttl\fR actions are nonstandard.
 .
 .IP \fBwrite_metadata\fB:\fIvalue\fR[/\fImask\fR]
 Updates the metadata field for the flow. If \fImask\fR is omitted, the
-- 
2.1.0



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