ovn-controller: Tie OpenFlow and logical flows using OpenFlow cookie.

This makes it easy to find the logical flow that generated a particular
OpenFlow flow, by running "ovn-sbctl dump-flows <cookie>".

Later, this can be refined (and automated for "ofproto/trace"), but this
is still a significant advance.

Signed-off-by: Ben Pfaff <blp@ovn.org>
Acked-by: Justin Pettit <jpettit@ovn.org>

7 files changed, 201 insertions, 54 deletions

diff --git a/ovn/controller/lflow.c b/ovn/controller/lflow.c
index d913998a3..9f5341a73 100644
--- a/ovn/controller/lflow.c
+++ b/ovn/controller/lflow.c
@@ -265,8 +265,8 @@ consider_logical_flow(const struct lport_index *lports,
             m->match.flow.conj_id += *conj_id_ofs_p;
         }
         if (!m->n) {
-            ofctrl_add_flow(flow_table, ptable, lflow->priority, &m->match,
-                            &ofpacts);
+            ofctrl_add_flow(flow_table, ptable, lflow->priority,
+                            lflow->header_.uuid.parts[0], &m->match, &ofpacts);
         } else {
             uint64_t conj_stubs[64 / 8];
             struct ofpbuf conj;
@@ -281,7 +281,7 @@ consider_logical_flow(const struct lport_index *lports,
                 dst->clause = src->clause;
                 dst->n_clauses = src->n_clauses;
             }
-            ofctrl_add_flow(flow_table, ptable, lflow->priority, &m->match,
+            ofctrl_add_flow(flow_table, ptable, lflow->priority, 0, &m->match,
                             &conj);
             ofpbuf_uninit(&conj);
         }
@@ -350,7 +350,7 @@ consider_neighbor_flow(const struct lport_index *lports,
     uint64_t stub[1024 / 8];
     struct ofpbuf ofpacts = OFPBUF_STUB_INITIALIZER(stub);
     put_load(mac.ea, sizeof mac.ea, MFF_ETH_DST, 0, 48, &ofpacts);
-    ofctrl_add_flow(flow_table, OFTABLE_MAC_BINDING, 100, &match, &ofpacts);
+    ofctrl_add_flow(flow_table, OFTABLE_MAC_BINDING, 100, 0, &match, &ofpacts);
     ofpbuf_uninit(&ofpacts);
 }
 
diff --git a/ovn/controller/ofctrl.c b/ovn/controller/ofctrl.c
index 1d8fbf308..c79660bf4 100644
--- a/ovn/controller/ofctrl.c
+++ b/ovn/controller/ofctrl.c
@@ -57,6 +57,7 @@ struct ovn_flow {
     /* Data. */
     struct ofpact *ofpacts;
     size_t ofpacts_len;
+    uint64_t cookie;
 };
 
 static uint32_t ovn_flow_hash(const struct ovn_flow *);
@@ -592,8 +593,8 @@ ofctrl_recv(const struct ofp_header *oh, enum ofptype type)
 /* Flow table interfaces to the rest of ovn-controller. */
 
 /* Adds a flow to 'desired_flows' with the specified 'match' and 'actions' to
- * the OpenFlow table numbered 'table_id' with the given 'priority'.  The
- * caller retains ownership of 'match' and 'actions'.
+ * the OpenFlow table numbered 'table_id' with the given 'priority' and
+ * OpenFlow 'cookie'.  The caller retains ownership of 'match' and 'actions'.
  *
  * This just assembles the desired flow table in memory.  Nothing is actually
  * sent to the switch until a later call to ofctrl_run().
@@ -601,8 +602,9 @@ ofctrl_recv(const struct ofp_header *oh, enum ofptype type)
  * The caller should initialize its own hmap to hold the flows. */
 void
 ofctrl_add_flow(struct hmap *desired_flows,
-                uint8_t table_id, uint16_t priority,
-                const struct match *match, const struct ofpbuf *actions)
+                uint8_t table_id, uint16_t priority, uint64_t cookie,
+                const struct match *match,
+                const struct ofpbuf *actions)
 {
     struct ovn_flow *f = xmalloc(sizeof *f);
     f->table_id = table_id;
@@ -611,6 +613,7 @@ ofctrl_add_flow(struct hmap *desired_flows,
     f->ofpacts = xmemdup(actions->data, actions->size);
     f->ofpacts_len = actions->size;
     f->hmap_node.hash = ovn_flow_hash(f);
+    f->cookie = cookie;
 
     if (ovn_flow_lookup(desired_flows, f)) {
         static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 5);
@@ -935,6 +938,7 @@ ofctrl_put(struct hmap *flow_table, struct shash *pending_ct_zones,
             .table_id = d->table_id,
             .ofpacts = d->ofpacts,
             .ofpacts_len = d->ofpacts_len,
+            .new_cookie = htonll(d->cookie),
             .command = OFPFC_ADD,
         };
         add_flow_mod(&fm, &msgs);
diff --git a/ovn/controller/ofctrl.h b/ovn/controller/ofctrl.h
index 5308b61b5..79f0cb780 100644
--- a/ovn/controller/ofctrl.h
+++ b/ovn/controller/ofctrl.h
@@ -45,8 +45,8 @@ void ofctrl_ct_flush_zone(uint16_t zone_id);
 
 /* Flow table interfaces to the rest of ovn-controller. */
 void ofctrl_add_flow(struct hmap *desired_flows, uint8_t table_id,
-                     uint16_t priority, const struct match *,
-                     const struct ofpbuf *ofpacts);
+                     uint16_t priority, uint64_t cookie,
+                     const struct match *, const struct ofpbuf *ofpacts);
 
 void ofctrl_flow_table_clear(void);
 
diff --git a/ovn/controller/physical.c b/ovn/controller/physical.c
index 9d3741051..9cc7eb682 100644
--- a/ovn/controller/physical.c
+++ b/ovn/controller/physical.c
@@ -218,7 +218,7 @@ put_local_common_flows(uint32_t dp_key, uint32_t port_key,
 
     /* Resubmit to table 34. */
     put_resubmit(OFTABLE_CHECK_LOOPBACK, ofpacts_p);
-    ofctrl_add_flow(flow_table, OFTABLE_LOCAL_OUTPUT, 100,
+    ofctrl_add_flow(flow_table, OFTABLE_LOCAL_OUTPUT, 100, 0,
                     &match, ofpacts_p);
 
     /* Table 34, Priority 100.
@@ -233,7 +233,7 @@ put_local_common_flows(uint32_t dp_key, uint32_t port_key,
                          0, MLF_ALLOW_LOOPBACK);
     match_set_reg(&match, MFF_LOG_INPORT - MFF_REG0, port_key);
     match_set_reg(&match, MFF_LOG_OUTPORT - MFF_REG0, port_key);
-    ofctrl_add_flow(flow_table, OFTABLE_CHECK_LOOPBACK, 100,
+    ofctrl_add_flow(flow_table, OFTABLE_CHECK_LOOPBACK, 100, 0,
                     &match, ofpacts_p);
 
     /* Table 64, Priority 100.
@@ -257,7 +257,8 @@ put_local_common_flows(uint32_t dp_key, uint32_t port_key,
     put_load(0, MFF_IN_PORT, 0, 16, ofpacts_p);
     put_resubmit(OFTABLE_LOG_TO_PHY, ofpacts_p);
     put_stack(MFF_IN_PORT, ofpact_put_STACK_POP(ofpacts_p));
-    ofctrl_add_flow(flow_table, OFTABLE_SAVE_INPORT, 100, &match, ofpacts_p);
+    ofctrl_add_flow(flow_table, OFTABLE_SAVE_INPORT, 100, 0,
+                    &match, ofpacts_p);
 }
 
 static void
@@ -346,7 +347,7 @@ consider_port_binding(enum mf_field_id mff_ovn_geneve,
         ofpacts_p->header = clone;
         ofpact_finish_CLONE(ofpacts_p, &clone);
 
-        ofctrl_add_flow(flow_table, OFTABLE_LOG_TO_PHY, 100,
+        ofctrl_add_flow(flow_table, OFTABLE_LOG_TO_PHY, 100, 0,
                         &match, ofpacts_p);
         return;
     }
@@ -471,7 +472,7 @@ consider_port_binding(enum mf_field_id mff_ovn_geneve,
         /* Resubmit to first logical ingress pipeline table. */
         put_resubmit(OFTABLE_LOG_INGRESS_PIPELINE, ofpacts_p);
         ofctrl_add_flow(flow_table, OFTABLE_PHY_TO_LOG,
-                        tag ? 150 : 100, &match, ofpacts_p);
+                        tag ? 150 : 100, 0, &match, ofpacts_p);
 
         if (!tag && (!strcmp(binding->type, "localnet")
                      || !strcmp(binding->type, "l2gateway"))) {
@@ -481,7 +482,7 @@ consider_port_binding(enum mf_field_id mff_ovn_geneve,
              * action. */
             ofpbuf_pull(ofpacts_p, ofpacts_orig_size);
             match_set_dl_tci_masked(&match, 0, htons(VLAN_CFI));
-            ofctrl_add_flow(flow_table, 0, 100, &match, ofpacts_p);
+            ofctrl_add_flow(flow_table, 0, 100, 0, &match, ofpacts_p);
         }
 
         /* Table 65, Priority 100.
@@ -508,7 +509,7 @@ consider_port_binding(enum mf_field_id mff_ovn_geneve,
              * switch will also contain the tag. */
             ofpact_put_STRIP_VLAN(ofpacts_p);
         }
-        ofctrl_add_flow(flow_table, OFTABLE_LOG_TO_PHY, 100,
+        ofctrl_add_flow(flow_table, OFTABLE_LOG_TO_PHY, 100, 0,
                         &match, ofpacts_p);
     } else if (!tun) {
         /* Remote port connected by localnet port */
@@ -531,7 +532,7 @@ consider_port_binding(enum mf_field_id mff_ovn_geneve,
 
         /* Resubmit to table 33. */
         put_resubmit(OFTABLE_LOCAL_OUTPUT, ofpacts_p);
-        ofctrl_add_flow(flow_table, OFTABLE_LOCAL_OUTPUT, 100,
+        ofctrl_add_flow(flow_table, OFTABLE_LOCAL_OUTPUT, 100, 0,
                         &match, ofpacts_p);
     } else {
         /* Remote port connected by tunnel */
@@ -555,7 +556,7 @@ consider_port_binding(enum mf_field_id mff_ovn_geneve,
 
         /* Output to tunnel. */
         ofpact_put_OUTPUT(ofpacts_p)->port = ofport;
-        ofctrl_add_flow(flow_table, OFTABLE_REMOTE_OUTPUT, 100,
+        ofctrl_add_flow(flow_table, OFTABLE_REMOTE_OUTPUT, 100, 0,
                         &match, ofpacts_p);
     }
 }
@@ -643,7 +644,7 @@ consider_mc_group(enum mf_field_id mff_ovn_geneve,
          * group as the logical output port. */
         put_load(mc->tunnel_key, MFF_LOG_OUTPORT, 0, 32, ofpacts_p);
 
-        ofctrl_add_flow(flow_table, OFTABLE_LOCAL_OUTPUT, 100,
+        ofctrl_add_flow(flow_table, OFTABLE_LOCAL_OUTPUT, 100, 0,
                         &match, ofpacts_p);
     }
 
@@ -681,7 +682,7 @@ consider_mc_group(enum mf_field_id mff_ovn_geneve,
             if (local_ports) {
                 put_resubmit(OFTABLE_LOCAL_OUTPUT, remote_ofpacts_p);
             }
-            ofctrl_add_flow(flow_table, OFTABLE_REMOTE_OUTPUT, 100,
+            ofctrl_add_flow(flow_table, OFTABLE_REMOTE_OUTPUT, 100, 0,
                             &match, remote_ofpacts_p);
         }
     }
@@ -882,7 +883,8 @@ physical_run(struct controller_ctx *ctx, enum mf_field_id mff_ovn_geneve,
 
         put_resubmit(OFTABLE_LOCAL_OUTPUT, &ofpacts);
 
-        ofctrl_add_flow(flow_table, OFTABLE_PHY_TO_LOG, 100, &match, &ofpacts);
+        ofctrl_add_flow(flow_table, OFTABLE_PHY_TO_LOG, 100, 0, &match,
+                        &ofpacts);
     }
 
     /* Add flows for VXLAN encapsulations.  Due to the limited amount of
@@ -914,7 +916,7 @@ physical_run(struct controller_ctx *ctx, enum mf_field_id mff_ovn_geneve,
             put_load(1, MFF_LOG_FLAGS, MLF_RCV_FROM_VXLAN_BIT, 1, &ofpacts);
             put_resubmit(OFTABLE_LOG_INGRESS_PIPELINE, &ofpacts);
 
-            ofctrl_add_flow(flow_table, OFTABLE_PHY_TO_LOG, 100, &match,
+            ofctrl_add_flow(flow_table, OFTABLE_PHY_TO_LOG, 100, 0, &match,
                             &ofpacts);
         }
     }
@@ -935,7 +937,8 @@ physical_run(struct controller_ctx *ctx, enum mf_field_id mff_ovn_geneve,
 
     /* Resubmit to table 33. */
     put_resubmit(OFTABLE_LOCAL_OUTPUT, &ofpacts);
-    ofctrl_add_flow(flow_table, OFTABLE_REMOTE_OUTPUT, 150, &match, &ofpacts);
+    ofctrl_add_flow(flow_table, OFTABLE_REMOTE_OUTPUT, 150, 0,
+                    &match, &ofpacts);
 
     /* Table 32, Priority 0.
      * =======================
@@ -945,7 +948,7 @@ physical_run(struct controller_ctx *ctx, enum mf_field_id mff_ovn_geneve,
     match_init_catchall(&match);
     ofpbuf_clear(&ofpacts);
     put_resubmit(OFTABLE_LOCAL_OUTPUT, &ofpacts);
-    ofctrl_add_flow(flow_table, OFTABLE_REMOTE_OUTPUT, 0, &match, &ofpacts);
+    ofctrl_add_flow(flow_table, OFTABLE_REMOTE_OUTPUT, 0, 0, &match, &ofpacts);
 
     /* Table 34, Priority 0.
      * =======================
@@ -959,7 +962,8 @@ physical_run(struct controller_ctx *ctx, enum mf_field_id mff_ovn_geneve,
         put_load(0, MFF_REG0 + i, 0, 32, &ofpacts);
     }
     put_resubmit(OFTABLE_LOG_EGRESS_PIPELINE, &ofpacts);
-    ofctrl_add_flow(flow_table, OFTABLE_CHECK_LOOPBACK, 0, &match, &ofpacts);
+    ofctrl_add_flow(flow_table, OFTABLE_CHECK_LOOPBACK, 0, 0, &match,
+                    &ofpacts);
 
     /* Table 64, Priority 0.
      * =======================
@@ -969,7 +973,7 @@ physical_run(struct controller_ctx *ctx, enum mf_field_id mff_ovn_geneve,
     match_init_catchall(&match);
     ofpbuf_clear(&ofpacts);
     put_resubmit(OFTABLE_LOG_TO_PHY, &ofpacts);
-    ofctrl_add_flow(flow_table, OFTABLE_SAVE_INPORT, 0, &match, &ofpacts);
+    ofctrl_add_flow(flow_table, OFTABLE_SAVE_INPORT, 0, 0, &match, &ofpacts);
 
     ofpbuf_uninit(&ofpacts);
 
diff --git a/ovn/ovn-architecture.7.xml b/ovn/ovn-architecture.7.xml
index d96e4b141..b049e51f0 100644
--- a/ovn/ovn-architecture.7.xml
+++ b/ovn/ovn-architecture.7.xml
@@ -846,6 +846,34 @@
       </p>
 
       <p>
+        Each logical flow maps to one or more OpenFlow flows.  An actual packet
+        ordinarily matches only one of these, although in some cases it can
+        match more than one of these flows (which is not a problem because all
+        of them have the same actions).  <code>ovn-controller</code> uses the
+        first 32 bits of the logical flow's UUID as the cookie for its OpenFlow
+        flow or flows.  (This is not necessarily unique, since the first 32
+        bits of a logical flow's UUID is not necessarily unique.)
+      </p>
+
+      <p>
+        Some logical flows can map to the Open vSwitch ``conjunctive match''
+        extension (see <code>ovs-ofctl</code>(8)).  Flows with a
+        <code>conjunction</code> action use an OpenFlow cookie of 0, because
+        they can correspond to multiple logical flows.  The OpenFlow flow for a
+        conjunctive match includes a match on <code>conj_id</code>.
+      </p>
+
+      <p>
+        Some logical flows may not be represented in the OpenFlow tables on a
+        given hypervisor, if they could not be used on that hypervisor.  For
+        example, if no VIF in a logical switch resides on a given hypervisor,
+        and the logical switch is not otherwise reachable on that hypervisor
+        (e.g. over a series of hops through logical switches and routers
+        starting from a VIF on the hypervisor), then the logical flow may not
+        be represented there.
+      </p>
+
+      <p>
         Most OVN actions have fairly obvious implementations in OpenFlow (with
         OVS extensions), e.g. <code>next;</code> is implemented as
         <code>resubmit</code>, <code><var>field</var> =
diff --git a/ovn/utilities/ovn-sbctl.8.in b/ovn/utilities/ovn-sbctl.8.in
index 783afc772..a87635de8 100644
--- a/ovn/utilities/ovn-sbctl.8.in
+++ b/ovn/utilities/ovn-sbctl.8.in
@@ -160,11 +160,25 @@ to unbind logical port that is not bound has no effect.
 .
 .SS "Logical Flow Commands"
 .
-.IP "\fBlflow\-list\fR [\fIlogical-datapath\fR]"
+.IP "[\fB\-\-uuid\fR] \fBlflow\-list\fR [\fIlogical-datapath\fR] [\fIlflow\fR...]"
 List logical flows.  If \fIlogical-datapath\fR is specified, only list
-flows for that logical datapath.
+flows for that logical datapath.  The \fIlogical-datapath\fR may be
+given as a UUID or as a datapath name (reporting an error if multiple
+datapaths have the same name).
+.IP
+If at least one \fIlflow\fR is given, only matching logical flows, if
+any, are listed.  Each \fIlflow\fR may be specified as a UUID or the
+first few characters of a UUID, optionally prefixed by \fB0x\fR.
+(Because \fBovn\-controller\fR sets OpenFlow flow cookies to the first
+32 bits of the corresponding logical flow's UUID, this makes it easy
+to look up the logical flow that generated a particular OpenFlow
+flow.)
+.IP
+If \fB\-\-uuid\fR is specified, the output includes the first 32 bits
+of each logical flow's UUID.  This makes it easier to find the
+OpenFlow flows that correspond to a given logical flow.
 .
-.IP "\fBdump\-flows\fR [\fIlogical-datapath\fR]"
+.IP "[\fB\-\-uuid\fR] \fBdump\-flows\fR [\fIlogical-datapath\fR]"
 Alias for \fBlflow\-list\fB.
 .
 .SS "Remote Connectivity Commands"
diff --git a/ovn/utilities/ovn-sbctl.c b/ovn/utilities/ovn-sbctl.c
index c190635b0..9e3016b65 100644
--- a/ovn/utilities/ovn-sbctl.c
+++ b/ovn/utilities/ovn-sbctl.c
@@ -304,8 +304,8 @@ Port binding commands:\n\
   lsp-unbind PORT             reset the port binding of logical port PORT\n\
 \n\
 Logical flow commands:\n\
-  lflow-list [DATAPATH]       List logical flows for all or a single datapath\n\
-  dump-flows [DATAPATH]       Alias for lflow-list\n\
+  lflow-list [DATAPATH] [LFLOW...] List logical flows for DATAPATH\n\
+  dump-flows [DATAPATH] [LFLOW...] Alias for lflow-list\n\
 \n\
 Connection commands:\n\
   get-connection             print the connections\n\
@@ -695,53 +695,148 @@ lflow_cmp(const void *lf1_, const void *lf2_)
     return 0;
 }
 
+static char *
+parse_partial_uuid(char *s)
+{
+    /* Accept a full or partial UUID. */
+    if (uuid_is_partial_string(s) == strlen(s)) {
+        return s;
+    }
+
+    /* Accept a full or partial UUID prefixed by 0x, since "ovs-ofctl
+     * dump-flows" prints cookies prefixed by 0x. */
+    if (s[0] == '0' && (s[1] == 'x' || s[1] == 'X')
+        && uuid_is_partial_string(s + 2) == strlen(s + 2)) {
+        return s + 2;
+    }
+
+    /* Not a (partial) UUID. */
+    return NULL;
+}
+
+static bool
+is_partial_uuid_match(const struct uuid *uuid, const char *match)
+{
+    char uuid_s[UUID_LEN + 1];
+    snprintf(uuid_s, sizeof uuid_s, UUID_FMT, UUID_ARGS(uuid));
+
+    return !strncmp(uuid_s, match, strlen(match));
+}
+
+static const struct sbrec_datapath_binding *
+lookup_datapath(struct ovsdb_idl *idl, const char *s)
+{
+    struct uuid uuid;
+    if (uuid_from_string(&uuid, s)) {
+        const struct sbrec_datapath_binding *datapath;
+        datapath = sbrec_datapath_binding_get_for_uuid(idl, &uuid);
+        if (datapath) {
+            return datapath;
+        }
+    }
+
+    const struct sbrec_datapath_binding *found = NULL;
+    const struct sbrec_datapath_binding *datapath;
+    SBREC_DATAPATH_BINDING_FOR_EACH (datapath, idl) {
+        const char *name = smap_get(&datapath->external_ids, "name");
+        if (name && !strcmp(name, s)) {
+            if (!found) {
+                found = datapath;
+            } else {
+                ctl_fatal("%s: multiple datapaths with this name", s);
+            }
+        }
+    }
+    return found;
+}
+
 static void
 cmd_lflow_list(struct ctl_context *ctx)
 {
-    const char *datapath = ctx->argc == 2 ? ctx->argv[1] : NULL;
-    struct uuid datapath_uuid = { .parts = { 0, }};
-    const struct sbrec_logical_flow **lflows;
-    const struct sbrec_logical_flow *lflow;
-    size_t n_flows = 0, n_capacity = 64;
+    const struct sbrec_datapath_binding *datapath = NULL;
+    if (ctx->argc > 1) {
+        datapath = lookup_datapath(ctx->idl, ctx->argv[1]);
+        if (datapath) {
+            ctx->argc--;
+            ctx->argv++;
+        }
+    }
 
-    if (datapath && !uuid_from_string(&datapath_uuid, datapath)) {
-        VLOG_ERR("Invalid format of datapath UUID");
-        return;
+    for (size_t i = 1; i < ctx->argc; i++) {
+        char *s = parse_partial_uuid(ctx->argv[i]);
+        if (!s) {
+            ctl_fatal("%s is not a UUID or the beginning of a UUID",
+                      ctx->argv[i]);
+        }
+        ctx->argv[i] = s;
     }
 
-    lflows = xmalloc(sizeof *lflows * n_capacity);
+    const struct sbrec_logical_flow **lflows = NULL;
+    size_t n_flows = 0;
+    size_t n_capacity = 0;
+    const struct sbrec_logical_flow *lflow;
     SBREC_LOGICAL_FLOW_FOR_EACH (lflow, ctx->idl) {
+        if (datapath && lflow->logical_datapath != datapath) {
+            continue;
+        }
+
         if (n_flows == n_capacity) {
             lflows = x2nrealloc(lflows, &n_capacity, sizeof *lflows);
         }
         lflows[n_flows] = lflow;
         n_flows++;
     }
-
     qsort(lflows, n_flows, sizeof *lflows, lflow_cmp);
 
-    const char *cur_pipeline = "";
-    size_t i;
-    for (i = 0; i < n_flows; i++) {
+    bool print_uuid = shash_find(&ctx->options, "--uuid") != NULL;
+
+    const struct sbrec_logical_flow *prev = NULL;
+    for (size_t i = 0; i < n_flows; i++) {
         lflow = lflows[i];
-        if (datapath && !uuid_equals(&datapath_uuid,
-                                     &lflow->logical_datapath->header_.uuid)) {
+
+        /* Figure out whether to print this particular flow.  By default, we
+         * print all flows, but if any UUIDs were listed on the command line
+         * then we only print the matching ones. */
+        bool include;
+        if (ctx->argc > 1) {
+            include = false;
+            for (size_t j = 1; j < ctx->argc; j++) {
+                if (is_partial_uuid_match(&lflow->header_.uuid,
+                                          ctx->argv[j])) {
+                    include = true;
+                    break;
+                }
+            }
+        } else {
+            include = true;
+        }
+        if (!include) {
             continue;
         }
-        if (strcmp(cur_pipeline, lflow->pipeline)) {
+
+        /* Print a header line for this datapath or pipeline, if we haven't
+         * already done so. */
+        if (!prev
+            || prev->logical_datapath != lflow->logical_datapath
+            || strcmp(prev->pipeline, lflow->pipeline)) {
             printf("Datapath: \"%s\" ("UUID_FMT")  Pipeline: %s\n",
                    smap_get_def(&lflow->logical_datapath->external_ids,
                                 "name", ""),
                    UUID_ARGS(&lflow->logical_datapath->header_.uuid),
                    lflow->pipeline);
-            cur_pipeline = lflow->pipeline;
         }
 
-        printf("  table=%-2" PRId64 "(%-19s), priority=%-5" PRId64
+        /* Print the flow. */
+        printf("  ");
+        if (print_uuid) {
+            printf("uuid=0x%08"PRIx32", ", lflow->header_.uuid.parts[0]);
+        }
+        printf("table=%-2"PRId64"(%-19s), priority=%-5"PRId64
                ", match=(%s), action=(%s)\n",
                lflow->table_id,
                smap_get_def(&lflow->external_ids, "stage-name", ""),
                lflow->priority, lflow->match, lflow->actions);
+        prev = lflow;
     }
 
     free(lflows);
@@ -1243,10 +1338,12 @@ static const struct ctl_command_syntax sbctl_commands[] = {
      "--if-exists", RW},
 
     /* Logical flow commands */
-    {"lflow-list", 0, 1, "[DATAPATH]", pre_get_info, cmd_lflow_list, NULL,
-     "", RO},
-    {"dump-flows", 0, 1, "[DATAPATH]", pre_get_info, cmd_lflow_list, NULL,
-     "", RO}, /* Friendly alias for lflow-list */
+    {"lflow-list", 0, INT_MAX, "[DATAPATH] [LFLOW...]",
+     pre_get_info, cmd_lflow_list, NULL,
+     "--uuid", RO},
+    {"dump-flows", 0, INT_MAX, "[DATAPATH] [LFLOW...]",
+     pre_get_info, cmd_lflow_list, NULL,
+     "--uuid", RO}, /* Friendly alias for lflow-list */
 
     /* Connection commands. */
     {"get-connection", 0, 0, "", pre_connection, cmd_get_connection, NULL, "", RO},