[ovs-dev] [PATCH v2 2/2] ovs-ofctl: Add "compose-packet" command for testing flow_compose().

Ben Pfaff blp at ovn.org
Sat Jan 27 17:06:35 UTC 2018


Thanks a lot for the review and for the fix to the comment.  I folded in
that fix and applied these patches to master.

On Fri, Jan 26, 2018 at 04:41:58PM -0800, Yifeng Sun wrote:
> Thanks for the patch. Tested and looks good to me.
> 
> I feel it may be a little better if the comment is changed like below:
> 
> - * can do something like "ovs-ofctl compose-packet udp | tcpdump -vvvv
> -r-" to
> + * can do something like "ovs-ofctl compose-packet udp --pcap | tcpdump
> -vvvv -r-" to
> 
> 
> Tested-by: Yifeng Sun <pkusunyifeng at gmail.com>
> 
> Reviewed-by: Yifeng Sun <pkusunyifeng at gmail.com>
> 
> On Fri, Jan 26, 2018 at 3:03 PM, Ben Pfaff <blp at ovn.org> wrote:
> 
> > I don't feel obligated to add a bunch of automatic tests for
> > flow_compose(), but this is handy for manual testing or for simple packet
> > generation.
> >
> > Signed-off-by: Ben Pfaff <blp at ovn.org>
> > ---
> >  utilities/ovs-ofctl.c | 72 ++++++++++++++++++++++++++++++
> > +++++++++++++++++++++
> >  1 file changed, 72 insertions(+)
> >
> > diff --git a/utilities/ovs-ofctl.c b/utilities/ovs-ofctl.c
> > index 953184da4d19..94bd9abd6dc1 100644
> > --- a/utilities/ovs-ofctl.c
> > +++ b/utilities/ovs-ofctl.c
> > @@ -138,6 +138,9 @@ static bool should_show_ports(void);
> >  /* --stats, --no-stats: Show statistics in flow dumps? */
> >  static int show_stats = 1;
> >
> > +/* --pcap: Makes "compose-packet" print a pcap on stdout. */
> > +static int print_pcap = 0;
> > +
> >  static const struct ovs_cmdl_command *get_all_commands(void);
> >
> >  OVS_NO_RETURN static void usage(void);
> > @@ -223,6 +226,7 @@ parse_options(int argc, char *argv[])
> >          {"bundle", no_argument, NULL, OPT_BUNDLE},
> >          {"color", optional_argument, NULL, OPT_COLOR},
> >          {"may-create", no_argument, NULL, OPT_MAY_CREATE},
> > +        {"pcap", no_argument, &print_pcap, 1},
> >          {"read-only", no_argument, NULL, OPT_READ_ONLY},
> >          DAEMON_LONG_OPTIONS,
> >          OFP_VERSION_LONG_OPTIONS,
> > @@ -4492,6 +4496,73 @@ ofctl_parse_key_value(struct ovs_cmdl_context *ctx)
> >      }
> >  }
> >
> > +/* "compose-packet [--pcap] FLOW [L7]": Converts the OpenFlow flow
> > + * specification FLOW to a packet with flow_compose() and prints the hex
> > bytes
> > + * in the packet on stdout.  Also verifies that the flow extracted from
> > that
> > + * packet matches the original FLOW.
> > + *
> > + * With --pcap, prints the packet to stdout instead as a pcap file, so
> > that you
> > + * can do something like "ovs-ofctl compose-packet udp | tcpdump -vvvv
> > -r-" to
> > + * use another tool to dump the packet contents.
> > + *
> > + * If L7 is specified, draws the L7 payload data from it, otherwise
> > defaults to
> > + * 64 bytes of payload. */
> > +static void
> > +ofctl_compose_packet(struct ovs_cmdl_context *ctx)
> > +{
> > +    if (print_pcap && isatty(STDOUT_FILENO)) {
> > +        ovs_fatal(1, "not writing pcap data to stdout; redirect to a file
> > "
> > +                  "or pipe to tcpdump instead");
> > +    }
> > +
> > +    struct flow flow1;
> > +    char *error = parse_ofp_exact_flow(&flow1, NULL, NULL, ctx->argv[1],
> > NULL);
> > +    if (error) {
> > +        ovs_fatal(0, "%s", error);
> > +    }
> > +
> > +    struct dp_packet p;
> > +    memset(&p, 0, sizeof p);
> > +    dp_packet_init(&p, 0);
> > +
> > +    void *l7 = NULL;
> > +    size_t l7_len = 64;
> > +    if (ctx->argc > 2) {
> > +        struct dp_packet payload;
> > +        memset(&payload, 0, sizeof payload);
> > +        dp_packet_init(&payload, 0);
> > +        if (dp_packet_put_hex(&payload, ctx->argv[2], NULL)[0] != '\0') {
> > +            ovs_fatal(0, "%s: trailing garbage in packet data",
> > ctx->argv[2]);
> > +        }
> > +        l7_len = dp_packet_size(&payload);
> > +        l7 = dp_packet_steal_data(&payload);
> > +    }
> > +    flow_compose(&p, &flow1, l7, l7_len);
> > +    free(l7);
> > +
> > +    if (print_pcap) {
> > +        ovs_pcap_write_header(stdout);
> > +        ovs_pcap_write(stdout, &p);
> > +    } else {
> > +        ovs_hex_dump(stdout, dp_packet_data(&p), dp_packet_size(&p), 0,
> > false);
> > +    }
> > +
> > +    struct flow flow2;
> > +    flow_extract(&p, &flow2);
> > +    flow2.in_port.ofp_port = OFPP_ANY;
> > +
> > +    dp_packet_uninit(&p);
> > +
> > +    if (!flow_equal(&flow1, &flow2)) {
> > +        fprintf(stderr, "specified and extracted flows differ:\n");
> > +        fputs("specified: ", stderr);
> > +        flow_print(stderr, &flow1, NULL);
> > +        fputs("\nextracted: ", stderr);
> > +        flow_print(stderr, &flow2, NULL);
> > +        exit(1);
> > +    }
> > +}
> > +
> >  static const struct ovs_cmdl_command all_commands[] = {
> >      { "show", "switch",
> >        1, 1, ofctl_show, OVS_RO },
> > @@ -4625,6 +4696,7 @@ static const struct ovs_cmdl_command all_commands[]
> > = {
> >      { "ofp-print", NULL, 1, 2, ofctl_ofp_print, OVS_RW },
> >      { "encode-hello", NULL, 1, 1, ofctl_encode_hello, OVS_RW },
> >      { "parse-key-value", NULL, 1, INT_MAX, ofctl_parse_key_value, OVS_RW
> > },
> > +    { "compose-packet", NULL, 1, 2, ofctl_compose_packet, OVS_RO },
> >
> >      { NULL, NULL, 0, 0, NULL, OVS_RO },
> >  };
> > --
> > 2.10.2
> >
> > _______________________________________________
> > dev mailing list
> > dev at openvswitch.org
> > https://mail.openvswitch.org/mailman/listinfo/ovs-dev
> >


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