ovs-ofctl: Add "ofp-parse" command for printing OpenFlow from a file.

Test provided by Alex Wang <alexw@nicira.com>.

Signed-off-by: Ben Pfaff <blp@nicira.com>

NEWS

@@ -20,6 +20,8 @@ v1.12.0 - xx xxx xxxx
       should look like "--private-key=db:Open_vSwitch,SSL,private_key").
     - Added ovs-dev.py, a utility script helpful for Open vSwitch developers.
     - Support for Linux kernels up to 3.9
+    - ovs-ofctl:
+      * New "ofp-parse" for printing OpenFlow messages read from a file.
 
 
 v1.11.0 - xx xxx xxxx

tests/ovs-ofctl.at

@@ -2272,3 +2272,21 @@ AT_CHECK([ovs-ofctl -F oxm -O openflow13], [1], [],
   [ovs-ofctl: missing command name; use --help for help
 ])
 AT_CLEANUP
+
+AT_SETUP([ovs-ofctl ofp-parse])
+# Test the echo request/reply messages (0 payload).
+AT_CHECK([printf '\1\2\0\10\0\0\0\0\1\3\0\10\0\0\0\0' > binary_ofp_msg])
+AT_CHECK([ovs-ofctl ofp-parse binary_ofp_msg], [0], [dnl
+OFPT_ECHO_REQUEST (xid=0x0): 0 bytes of payload
+OFPT_ECHO_REPLY (xid=0x0): 0 bytes of payload
+])
+
+# Test the hello (xid:1 3-byte payload).
+AT_CHECK([printf '\1\0\0\13\0\0\0\1\101\102\103' > binary_ofp_msg])
+AT_CHECK([ovs-ofctl ofp-parse - < binary_ofp_msg], [0], [dnl
+OFPT_HELLO (xid=0x1):
+ version bitmap: 0x01
+ unknown data in hello:
+00000000  01 00 00 0b 00 00 00 01-41 42 43                |........ABC     |
+])
+AT_CLEANUP

utilities/ovs-ofctl.8.in

@@ -370,6 +370,14 @@ response.  Reports the total time required.  This is a measure of the
 maximum bandwidth to \fItarget\fR for round-trips of \fIn\fR-byte
 messages.
 .
+.SS "Other Commands"
+.
+.IP "\fBofp\-parse\fR \fIfile\fR"
+Reads \fIfile\fR (or \fBstdin\fR if \fIfile\fR is \fB\-\fR) as a
+series of OpenFlow messages in the binary format used on an OpenFlow
+connection, and prints them to the console.  This can be useful for
+printing OpenFlow messages captured from a TCP stream.
+.
 .SS "Flow Syntax"
 .PP
 Some \fBovs\-ofctl\fR commands accept an argument that describes a flow or

utilities/ovs-ofctl.c

@@ -305,7 +305,9 @@ usage(void)
            "  probe TARGET                probe whether TARGET is up\n"
            "  ping TARGET [N]             latency of N-byte echos\n"
            "  benchmark TARGET N COUNT    bandwidth of COUNT N-byte echos\n"
-           "where SWITCH or TARGET is an active OpenFlow connection method.\n",
+           "SWITCH or TARGET is an active OpenFlow connection method.\n"
+           "\nOther commands:\n"
+           "  ofp-parse FILE              print messages read from FILE\n",
            program_name, program_name);
     vconn_usage(true, false, false);
     daemon_usage();
@@ -1696,6 +1698,56 @@ ofctl_set_frags(int argc OVS_UNUSED, char *argv[])
     vconn_close(vconn);
 }
 
+static void
+ofctl_ofp_parse(int argc OVS_UNUSED, char *argv[])
+{
+    const char *filename = argv[1];
+    struct ofpbuf b;
+    FILE *file;
+
+    file = !strcmp(filename, "-") ? stdin : fopen(filename, "r");
+    if (file == NULL) {
+        ovs_fatal(errno, "%s: open", filename);
+    }
+
+    ofpbuf_init(&b, 65536);
+    for (;;) {
+        struct ofp_header *oh;
+        size_t length, tail_len;
+        void *tail;
+        size_t n;
+
+        ofpbuf_clear(&b);
+        oh = ofpbuf_put_uninit(&b, sizeof *oh);
+        n = fread(oh, 1, sizeof *oh, file);
+        if (n == 0) {
+            break;
+        } else if (n < sizeof *oh) {
+            ovs_fatal(0, "%s: unexpected end of file mid-message", filename);
+        }
+
+        length = ntohs(oh->length);
+        if (length < sizeof *oh) {
+            ovs_fatal(0, "%s: %zu-byte message is too short for OpenFlow",
+                      filename, length);
+        }
+
+        tail_len = length - sizeof *oh;
+        tail = ofpbuf_put_uninit(&b, tail_len);
+        n = fread(tail, 1, tail_len, file);
+        if (n < tail_len) {
+            ovs_fatal(0, "%s: unexpected end of file mid-message", filename);
+        }
+
+        ofp_print(stdout, b.data, b.size, verbosity + 2);
+    }
+    ofpbuf_uninit(&b);
+
+    if (file != stdin) {
+        fclose(file);
+    }
+}
+
 static void
 ofctl_ping(int argc, char *argv[])
 {
@@ -2932,6 +2984,7 @@ static const struct command all_commands[] = {
     { "mod-port", 3, 3, ofctl_mod_port },
     { "get-frags", 1, 1, ofctl_get_frags },
     { "set-frags", 2, 2, ofctl_set_frags },
+    { "ofp-parse", 1, 1, ofctl_ofp_parse },
     { "probe", 1, 1, ofctl_probe },
     { "ping", 1, 2, ofctl_ping },
     { "benchmark", 3, 3, ofctl_benchmark },