ofproto-dpif: New unixctl command ofproto/trace-packet-out.

Feature #20543. Requested-by: Ronghua Zhang <[email protected]> Signed-off-by: Ben Pfaff <[email protected]>
xnox · Nov 11, 2013 · aee0979 · aee0979
1 parent dc8ce81
commit aee0979
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Showing 3 changed files with 182 additions and 28 deletions.
diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c
@@ -537,7 +537,9 @@ ofproto_dpif_cast(const struct ofproto *ofproto)
 static struct ofport_dpif *get_ofp_port(const struct ofproto_dpif *ofproto,
                                         ofp_port_t ofp_port);
 static void ofproto_trace(struct ofproto_dpif *, const struct flow *,
-                          const struct ofpbuf *packet, struct ds *);
+                          const struct ofpbuf *packet,
+                          const struct ofpact[], size_t ofpacts_len,
+                          struct ds *);
 
 /* Upcalls. */
 static void handle_upcalls(struct dpif_backer *);
@@ -5418,7 +5420,7 @@ ofproto_unixctl_trace(struct unixctl_conn *conn, int argc, const char *argv[],
         struct ds result;
 
         ds_init(&result);
-        ofproto_trace(ofproto, &flow, packet, &result);
+        ofproto_trace(ofproto, &flow, packet, NULL, 0, &result);
         unixctl_command_reply(conn, ds_cstr(&result));
         ds_destroy(&result);
         ofpbuf_delete(packet);
@@ -5427,32 +5429,128 @@ ofproto_unixctl_trace(struct unixctl_conn *conn, int argc, const char *argv[],
     }
 }
 
+static void
+ofproto_unixctl_trace_actions(struct unixctl_conn *conn, int argc,
+                              const char *argv[], void *aux OVS_UNUSED)
+{
+    enum ofputil_protocol usable_protocols;
+    struct ofproto_dpif *ofproto;
+    bool enforce_consistency;
+    struct ofpbuf ofpacts;
+    struct ofpbuf *packet;
+    struct ds result;
+    struct flow flow;
+    uint16_t in_port;
+
+    /* Three kinds of error return values! */
+    enum ofperr retval;
+    const char *error;
+    char *rw_error;
+
+    packet = NULL;
+    ds_init(&result);
+    ofpbuf_init(&ofpacts, 0);
+
+    /* Parse actions. */
+    rw_error = parse_ofpacts(argv[--argc], &ofpacts, &usable_protocols);
+    if (rw_error) {
+        unixctl_command_reply_error(conn, rw_error);
+        free(rw_error);
+        goto exit;
+    }
+
+    /* OpenFlow 1.1 and later suggest that the switch enforces certain forms of
+     * consistency between the flow and the actions, so enforce these by
+     * default if the actions can only work in OF1.1 or later. */
+    enforce_consistency = !(usable_protocols & OFPUTIL_P_OF10_ANY);
+    if (!strcmp(argv[1], "-consistent")) {
+        enforce_consistency = true;
+        argv++;
+        argc--;
+    }
+
+    error = parse_flow_and_packet(argc, argv, &ofproto, &flow, &packet);
+    if (error) {
+        unixctl_command_reply_error(conn, error);
+        goto exit;
+    }
+
+    /* Do the same checks as handle_packet_out() in ofproto.c.
+     *
+     * We pass a 'table_id' of 0 to ofproto_check_ofpacts(), which isn't
+     * strictly correct because these actions aren't in any table, but it's OK
+     * because it 'table_id' is used only to check goto_table instructions, but
+     * packet-outs take a list of actions and therefore it can't include
+     * instructions.
+     *
+     * We skip the "meter" check here because meter is an instruction, not an
+     * action, and thus cannot appear in ofpacts. */
+    in_port = ofp_to_u16(flow.in_port.ofp_port);
+    if (in_port >= ofproto->up.max_ports && in_port < ofp_to_u16(OFPP_MAX)) {
+        unixctl_command_reply_error(conn, "invalid in_port");
+        goto exit;
+    }
+    retval = ofpacts_check(ofpacts.data, ofpacts.size, &flow,
+                           enforce_consistency,
+                           u16_to_ofp(ofproto->up.max_ports), 0, 0);
+    if (retval) {
+        ds_clear(&result);
+        ds_put_format(&result, "Bad actions: %s", ofperr_to_string(retval));
+        unixctl_command_reply_error(conn, ds_cstr(&result));
+        goto exit;
+    }
+
+    ofproto_trace(ofproto, &flow, packet, ofpacts.data, ofpacts.size, &result);
+    unixctl_command_reply(conn, ds_cstr(&result));
+
+exit:
+    ds_destroy(&result);
+    ofpbuf_delete(packet);
+    ofpbuf_uninit(&ofpacts);
+}
+
+/* Implements a "trace" through 'ofproto''s flow table, appending a textual
+ * description of the results to 'ds'.
+ *
+ * The trace follows a packet with the specified 'flow' through the flow
+ * table.  'packet' may be nonnull to trace an actual packet, with consequent
+ * side effects (if it is nonnull then its flow must be 'flow').
+ *
+ * If 'ofpacts' is nonnull then its 'ofpacts_len' bytes specify the actions to
+ * trace, otherwise the actions are determined by a flow table lookup. */
 static void
 ofproto_trace(struct ofproto_dpif *ofproto, const struct flow *flow,
-              const struct ofpbuf *packet, struct ds *ds)
+              const struct ofpbuf *packet,
+              const struct ofpact ofpacts[], size_t ofpacts_len,
+              struct ds *ds)
 {
     struct rule_dpif *rule;
     struct flow_wildcards wc;
 
+    ds_put_format(ds, "Bridge: %s\n", ofproto->up.name);
     ds_put_cstr(ds, "Flow: ");
     flow_format(ds, flow);
     ds_put_char(ds, '\n');
 
     flow_wildcards_init_catchall(&wc);
-    rule_dpif_lookup(ofproto, flow, &wc, &rule);
+    if (ofpacts) {
+        rule = NULL;
+    } else {
+        rule_dpif_lookup(ofproto, flow, &wc, &rule);
 
-    trace_format_rule(ds, 0, rule);
-    if (rule == ofproto->miss_rule) {
-        ds_put_cstr(ds, "\nNo match, flow generates \"packet in\"s.\n");
-    } else if (rule == ofproto->no_packet_in_rule) {
-        ds_put_cstr(ds, "\nNo match, packets dropped because "
-                    "OFPPC_NO_PACKET_IN is set on in_port.\n");
-    } else if (rule == ofproto->drop_frags_rule) {
-        ds_put_cstr(ds, "\nPackets dropped because they are IP fragments "
-                    "and the fragment handling mode is \"drop\".\n");
+        trace_format_rule(ds, 0, rule);
+        if (rule == ofproto->miss_rule) {
+            ds_put_cstr(ds, "\nNo match, flow generates \"packet in\"s.\n");
+        } else if (rule == ofproto->no_packet_in_rule) {
+            ds_put_cstr(ds, "\nNo match, packets dropped because "
+                        "OFPPC_NO_PACKET_IN is set on in_port.\n");
+        } else if (rule == ofproto->drop_frags_rule) {
+            ds_put_cstr(ds, "\nPackets dropped because they are IP fragments "
+                        "and the fragment handling mode is \"drop\".\n");
+        }
     }
 
-    if (rule) {
+    if (rule || ofpacts) {
         uint64_t odp_actions_stub[1024 / 8];
         struct ofpbuf odp_actions;
         struct trace_ctx trace;
@@ -5465,6 +5563,10 @@ ofproto_trace(struct ofproto_dpif *ofproto, const struct flow *flow,
         ofpbuf_use_stub(&odp_actions,
                         odp_actions_stub, sizeof odp_actions_stub);
         xlate_in_init(&trace.xin, ofproto, flow, rule, tcp_flags, packet);
+        if (ofpacts) {
+            trace.xin.ofpacts = ofpacts;
+            trace.xin.ofpacts_len = ofpacts_len;
+        }
         trace.xin.resubmit_hook = trace_resubmit;
         trace.xin.report_hook = trace_report;
 
@@ -5900,6 +6002,10 @@ ofproto_dpif_unixctl_init(void)
         "ofproto/trace",
         "{[dp_name] odp_flow | bridge br_flow} [-generate|packet]",
         1, 3, ofproto_unixctl_trace, NULL);
+    unixctl_command_register(
+        "ofproto/trace-packet-out",
+        "[-consistent] {[dp_name] odp_flow | bridge br_flow} [-generate|packet] actions",
+        2, 6, ofproto_unixctl_trace_actions, NULL);
     unixctl_command_register("fdb/flush", "[bridge]", 0, 1,
                              ofproto_unixctl_fdb_flush, NULL);
     unixctl_command_register("fdb/show", "bridge", 1, 1,

diff --git a/ofproto/ofproto-unixctl.man b/ofproto/ofproto-unixctl.man
@@ -6,15 +6,30 @@ These commands manage the core OpenFlow switch implementation (called
 Lists the names of the running ofproto instances.  These are the names
 that may be used on \fBofproto/trace\fR.
 .
-.IP "\fBofproto/trace\fR [\fIdpname\fR] \fIodp_flow\fR [\fB\-generate \fR| \
-\fIpacket\fR]"
-.IQ "\fBofproto/trace\fR \fIbridge\fR \fIbr_flow\fR \
-[\fB\-generate \fR| \fIpacket\fR]"
+.IP "\fBofproto/trace\fR [\fIdpname\fR] \fIodp_flow\fR [\fB\-generate \fR| \fIpacket\fR]"
+.IQ "\fBofproto/trace\fR \fIbridge\fR \fIbr_flow\fR [\fB\-generate \fR| \fIpacket\fR]"
+.IQ "\fBofproto/trace\-packet\-out\fR [\fB\-consistent\fR] [\fIdpname\fR] \fIodp_flow\fR [\fB\-generate \fR| \fIpacket\fR] \fIactions\fR"
+.IQ "\fBofproto/trace\-packet\-out\fR [\fB\-consistent\fR] \fIbridge\fR \fIbr_flow\fR [\fB\-generate \fR| \fIpacket\fR] \fIactions\fR"
 Traces the path of an imaginary packet through \fIswitch\fR and
-reports the path that it took.  The packet's headers (e.g. source and
-destination) and metadata (e.g. input port), together called its
-``flow,'' are usually all that matter for this purpose.  You can
-specify the flow in the following ways:
+reports the path that it took.  The initial treatment of the packet
+varies based on the command:
+.
+.RS
+.IP \(bu
+\fBofproto/trace\fR looks the packet up in the OpenFlow flow table, as
+if the packet had arrived on an OpenFlow port.
+.
+.IP \(bu
+\fBofproto/trace\-packet\-out\fR applies the specified OpenFlow
+\fIactions\fR, as if the packet, flow, and actions had been specified
+in an OpenFlow ``packet-out'' request.
+.RE
+.
+.IP
+The packet's headers (e.g. source and destination) and metadata
+(e.g. input port), together called its ``flow,'' are usually all that
+matter for the purpose of tracing a packet.  You can specify the flow
+in the following ways:
 .
 .RS
 .IP "\fIdpname\fR \fIodp_flow\fR"
@@ -41,26 +56,26 @@ instead of just a flow:
 .IP "Side effects."
 Some actions have side effects.  For example, the \fBnormal\fR action
 can update the MAC learning table, and the \fBlearn\fR action can
-change OpenFlow tables.  \fBofproto/trace\fR only performs side
+change OpenFlow tables.  The trace commands only perform side
 effects when a packet is specified.  If you want side effects to take
 place, then you must supply a packet.
 .
 .IP
 (Output actions are obviously side effects too, but
-\fBofproto/trace\fR never executes them, even when one specifies a
+the trace commands never execute them, even when one specifies a
 packet.)
 .
 .IP "Incomplete information."
 Most of the time, Open vSwitch can figure out everything about the
 path of a packet using just the flow, but in some special
 circumstances it needs to look at parts of the packet that are not
 included in the flow.  When this is the case, and you do not supply a
-packet, then \fBofproto/trace\fR will tell you it needs a packet.
+packet, then a trace command will tell you it needs a packet.
 .RE
 .
 .IP
-If you wish to include a packet as part of the \fBofproto/trace\fR
-operation, there are two ways to do it:
+If you wish to include a packet as part of a trace operation, there
+are two ways to do it:
 .
 .RS
 .IP \fB\-generate\fR
@@ -93,11 +108,25 @@ The tunnel ID on which the packet arrived.
 .IP \fIin_port\fR
 The port on which the packet arrived.
 .RE
+.RE
 .
+.IP
 The in_port value is kernel datapath port number for the first format
 and OpenFlow port number for the second format. The numbering of these
 two types of port usually differs and there is no relationship.
-.RE
+.
+.IP
+\fBofproto\-trace\-packet\-out\fR accepts an additional
+\fB\-consistent\fR option.  With this option specified, the command
+rejects \fIactions\fR that are inconsistent with the specified packet.
+(An example of an inconsistency is attempting to strip the VLAN tag
+from a packet that does not have a VLAN tag.)  Open vSwitch ignores
+most forms of inconsistency in OpenFlow 1.0 and rejects
+inconsistencies in later versions of OpenFlow.  The option is
+necessary because the command does not ordinarily imply a particular
+OpenFlow version.  One exception is that, when \fIactions\fR includes
+an action that only OpenFlow 1.1 and later supports (such as
+\fBpush_vlan\fR), \fB\-consistent\fR is automatically enabled.
 .IP "\fBofproto/self\-check\fR [\fIswitch\fR]"
 Runs an internal consistency check on \fIswitch\fR, if specified,
 otherwise on all ofproto instances, and responds with a brief summary

diff --git a/tests/ofproto-dpif.at b/tests/ofproto-dpif.at
@@ -1608,6 +1608,25 @@ ovs-appctl: ovs-vswitchd: server returned an error
 OVS_VSWITCHD_STOP
 AT_CLEANUP
 
+AT_SETUP([ofproto-dpif - ofproto/trace-packet-out])
+OVS_VSWITCHD_START
+ADD_OF_PORTS([br0], 1, 2, 3)
+
+AT_DATA([flows.txt], [dnl
+in_port=1 actions=output:2
+in_port=2 actions=output:1
+])
+AT_CHECK([ovs-ofctl add-flows br0 flows.txt])
+
+AT_CHECK([ovs-appctl ofproto/trace-packet-out br0 in_port=1 'mod_vlan_vid:123,resubmit(,0)'], [0], [stdout])
+AT_CHECK([tail -1 stdout], [0], [dnl
+Datapath actions: push_vlan(vid=123,pcp=0),2
+])
+
+OVS_VSWITCHD_STOP
+AT_CLEANUP
+
+
 m4_define([OFPROTO_TRACE],
   [flow="$2"
    AT_CHECK([ovs-appctl ofproto/trace $1 "$flow" $3], [0], [stdout])