nsh: add dec_nsh_ttl action

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@intel.com> Signed-off-by: Ben Pfaff <blp@ovn.org>
2025-08-31 06:15:47 +00:00 · 2018-01-11 13:24:03 +08:00
parent 81fdabb94d
commit 491e05c233
6 changed files with 97 additions and 4 deletions
--- a/1
+++ b/1
@@ -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).
--- 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")         \
--- 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. ## */
 /* ## ------------------ ## */
@@ -486,6 +489,7 @@ 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:
@@ -4336,6 +4340,39 @@ 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.
@@ -7156,6 +7193,7 @@ 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:
@@ -7234,6 +7272,7 @@ 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
@@ -7348,6 +7387,7 @@ 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);

@@ -7490,6 +7530,7 @@ 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;
    }
@@ -8177,6 +8218,13 @@ 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();
    }
@@ -8673,6 +8721,7 @@ 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;
    }
--- a/ofproto/ofproto-dpif-xlate.c
+++ b/ofproto/ofproto-dpif-xlate.c
@@ -4647,6 +4647,28 @@ 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 {
+            xlate_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)
 {
@@ -5196,6 +5218,7 @@ 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;
        }
    }
@@ -5423,6 +5446,7 @@ 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. */
@@ -5971,6 +5995,7 @@ 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:
@@ -6295,6 +6320,12 @@ 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))) {
--- 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
--- 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