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

[Ben Pfaff]

Signed-off-by: Ben Pfaff <blp at nicira.com
---
 NEWS                     |    2 +
 utilities/ovs-ofctl.8.in |    8 ++++++
 utilities/ovs-ofctl.c    |   55 +++++++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 64 insertions(+), 1 deletions(-)

diff --git a/NEWS b/NEWS
index b46fc43..bb174ed 100644
--- a/NEWS
+++ b/NEWS
@@ -15,6 +15,8 @@ post-v1.11.0
       through database paths (e.g. Private key option with the database name
       should look like "--private-key=db:Open_vSwitch,SSL,private_key").
     - Added ovs-dev.py, a utility script helpful for Open vSwitch developers.
+    - ovs-ofctl:
+      * New "ofp-parse" for printing OpenFlow messages read from a file.
 
 
 v1.11.0 - xx xxx xxxx
diff --git a/utilities/ovs-ofctl.8.in b/utilities/ovs-ofctl.8.in
index e66c605..3e6c7fe 100644
--- a/utilities/ovs-ofctl.8.in
+++ b/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
diff --git a/utilities/ovs-ofctl.c b/utilities/ovs-ofctl.c
index 2622255..577c4ce 100644
--- a/utilities/ovs-ofctl.c
+++ b/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();
@@ -1697,6 +1699,56 @@ ofctl_set_frags(int argc OVS_UNUSED, char *argv[])
 }
 
 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[])
 {
     size_t max_payload = 65535 - sizeof(struct ofp_header);
@@ -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 },
-- 
1.7.2.5