selftests/net: so_txtime multi-host support

SO_TXTIME hardware offload requires testing across devices, either
between machines or separate network namespaces.

Split up SO_TXTIME test into tx and rx modes, so traffic can be
sent from one process to another. Create a veth-pair on different
namespaces and bind each process to an end point via [-S]ource and
[-D]estination parameters. Optional start [-t]ime parameter can be
passed to synchronize the test across the hosts (with synchorinzed
clocks).

Signed-off-by: Carlos Llamas <cmllamas@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/tools/testing/selftests/net/so_txtime.c b/tools/testing/selftests/net/so_txtime.c
index b4cca382d125491dc35ec669bf91240d2b35e289..59067f64b775384161a4586ba97eb435b4d88bcd 100644 (file)
--- a/tools/testing/selftests/net/so_txtime.c
+++ b/tools/testing/selftests/net/so_txtime.c
@@ -2,9 +2,12 @@
 /*
  * Test the SO_TXTIME API
  *
 /*
  * Test the SO_TXTIME API
  *

- * Takes two streams of { payload, delivery time }[], one input and one output.
- * Sends the input stream and verifies arrival matches the output stream.
- * The two streams can differ due to out-of-order delivery and drops.
+ * Takes a stream of { payload, delivery time }[], to be sent across two
+ * processes. Start this program on two separate network namespaces or
+ * connected hosts, one instance in transmit mode and the other in receive
+ * mode using the '-r' option. Receiver will compare arrival timestamps to
+ * the expected stream. Sender will read transmit timestamps from the error
+ * queue. The streams can differ due to out-of-order delivery and drops.

  */
 
 #define _GNU_SOURCE
  */
 
 #define _GNU_SOURCE


@@ -28,14 +31,17 @@
 #include <sys/types.h>
 #include <time.h>
 #include <unistd.h>
 #include <sys/types.h>
 #include <time.h>
 #include <unistd.h>

+#include <poll.h>

 
 static int     cfg_clockid     = CLOCK_TAI;
 
 static int     cfg_clockid     = CLOCK_TAI;

-static bool    cfg_do_ipv4;
-static bool    cfg_do_ipv6;

 static uint16_t        cfg_port        = 8000;
 static int     cfg_variance_us = 4000;
 static uint16_t        cfg_port        = 8000;
 static int     cfg_variance_us = 4000;

+static uint64_t        cfg_start_time_ns;
+static int     cfg_mark;
+static bool    cfg_rx;

 
 static uint64_t glob_tstart;
 
 static uint64_t glob_tstart;

+static uint64_t tdeliver_max;

 
 /* encode one timed transmission (of a 1B payload) */
 struct timed_send {
 
 /* encode one timed transmission (of a 1B payload) */
 struct timed_send {


@@ -44,18 +50,21 @@ struct timed_send {
 };
 
 #define MAX_NUM_PKT    8
 };
 
 #define MAX_NUM_PKT    8

-static struct timed_send cfg_in[MAX_NUM_PKT];
-static struct timed_send cfg_out[MAX_NUM_PKT];
+static struct timed_send cfg_buf[MAX_NUM_PKT];

 static int cfg_num_pkt;
 
 static int cfg_errq_level;
 static int cfg_errq_type;
 
 static int cfg_num_pkt;
 
 static int cfg_errq_level;
 static int cfg_errq_type;
 

-static uint64_t gettime_ns(void)
+static struct sockaddr_storage cfg_dst_addr;
+static struct sockaddr_storage cfg_src_addr;
+static socklen_t cfg_alen;
+
+static uint64_t gettime_ns(clockid_t clock)

 {
        struct timespec ts;
 
 {
        struct timespec ts;
 

-       if (clock_gettime(cfg_clockid, &ts))
+       if (clock_gettime(clock, &ts))

                error(1, errno, "gettime");
 
        return ts.tv_sec * (1000ULL * 1000 * 1000) + ts.tv_nsec;
                error(1, errno, "gettime");
 
        return ts.tv_sec * (1000ULL * 1000 * 1000) + ts.tv_nsec;


@@ -75,6 +84,8 @@ static void do_send_one(int fdt, struct timed_send *ts)
 
        msg.msg_iov = &iov;
        msg.msg_iovlen = 1;
 
        msg.msg_iov = &iov;
        msg.msg_iovlen = 1;

+       msg.msg_name = (struct sockaddr *)&cfg_dst_addr;
+       msg.msg_namelen = cfg_alen;

 
        if (ts->delay_us >= 0) {
                memset(control, 0, sizeof(control));
 
        if (ts->delay_us >= 0) {
                memset(control, 0, sizeof(control));


@@ -82,6 +93,8 @@ static void do_send_one(int fdt, struct timed_send *ts)
                msg.msg_controllen = sizeof(control);
 
                tdeliver = glob_tstart + ts->delay_us * 1000;
                msg.msg_controllen = sizeof(control);
 
                tdeliver = glob_tstart + ts->delay_us * 1000;

+               tdeliver_max = tdeliver_max > tdeliver ?
+                              tdeliver_max : tdeliver;

 
                cm = CMSG_FIRSTHDR(&msg);
                cm->cmsg_level = SOL_SOCKET;
 
                cm = CMSG_FIRSTHDR(&msg);
                cm->cmsg_level = SOL_SOCKET;


@@ -98,7 +111,7 @@ static void do_send_one(int fdt, struct timed_send *ts)
 
 }
 
 
 }
 

-static bool do_recv_one(int fdr, struct timed_send *ts)
+static void do_recv_one(int fdr, struct timed_send *ts)

 {
        int64_t tstop, texpect;
        char rbuf[2];
 {
        int64_t tstop, texpect;
        char rbuf[2];


@@ -106,13 +119,13 @@ static bool do_recv_one(int fdr, struct timed_send *ts)
 
        ret = recv(fdr, rbuf, sizeof(rbuf), 0);
        if (ret == -1 && errno == EAGAIN)
 
        ret = recv(fdr, rbuf, sizeof(rbuf), 0);
        if (ret == -1 && errno == EAGAIN)

-               return true;
+               error(1, EAGAIN, "recv: timeout");

        if (ret == -1)
                error(1, errno, "read");
        if (ret != 1)
                error(1, 0, "read: %dB", ret);
 
        if (ret == -1)
                error(1, errno, "read");
        if (ret != 1)
                error(1, 0, "read: %dB", ret);
 

-       tstop = (gettime_ns() - glob_tstart) / 1000;
+       tstop = (gettime_ns(cfg_clockid) - glob_tstart) / 1000;

        texpect = ts->delay_us >= 0 ? ts->delay_us : 0;
 
        fprintf(stderr, "payload:%c delay:%lld expected:%lld (us)\n",
        texpect = ts->delay_us >= 0 ? ts->delay_us : 0;
 
        fprintf(stderr, "payload:%c delay:%lld expected:%lld (us)\n",


@@ -123,8 +136,6 @@ static bool do_recv_one(int fdr, struct timed_send *ts)
 
        if (llabs(tstop - texpect) > cfg_variance_us)
                error(1, 0, "exceeds variance (%d us)", cfg_variance_us);
 
        if (llabs(tstop - texpect) > cfg_variance_us)
                error(1, 0, "exceeds variance (%d us)", cfg_variance_us);

-
-       return false;

 }
 
 static void do_recv_verify_empty(int fdr)
 }
 
 static void do_recv_verify_empty(int fdr)


@@ -137,18 +148,18 @@ static void do_recv_verify_empty(int fdr)
                error(1, 0, "recv: not empty as expected (%d, %d)", ret, errno);
 }
 
                error(1, 0, "recv: not empty as expected (%d, %d)", ret, errno);
 }
 

-static void do_recv_errqueue_timeout(int fdt)
+static int do_recv_errqueue_timeout(int fdt)

 {
        char control[CMSG_SPACE(sizeof(struct sock_extended_err)) +
                     CMSG_SPACE(sizeof(struct sockaddr_in6))] = {0};
        char data[sizeof(struct ethhdr) + sizeof(struct ipv6hdr) +
                  sizeof(struct udphdr) + 1];
        struct sock_extended_err *err;
 {
        char control[CMSG_SPACE(sizeof(struct sock_extended_err)) +
                     CMSG_SPACE(sizeof(struct sockaddr_in6))] = {0};
        char data[sizeof(struct ethhdr) + sizeof(struct ipv6hdr) +
                  sizeof(struct udphdr) + 1];
        struct sock_extended_err *err;

+       int ret, num_tstamp = 0;

        struct msghdr msg = {0};
        struct iovec iov = {0};
        struct cmsghdr *cm;
        int64_t tstamp = 0;
        struct msghdr msg = {0};
        struct iovec iov = {0};
        struct cmsghdr *cm;
        int64_t tstamp = 0;

-       int ret;

 
        iov.iov_base = data;
        iov.iov_len = sizeof(data);
 
        iov.iov_base = data;
        iov.iov_len = sizeof(data);


@@ -206,9 +217,47 @@ static void do_recv_errqueue_timeout(int fdt)
 
                msg.msg_flags = 0;
                msg.msg_controllen = sizeof(control);
 
                msg.msg_flags = 0;
                msg.msg_controllen = sizeof(control);

+               num_tstamp++;

        }
 
        }
 

-       error(1, 0, "recv: timeout");
+       return num_tstamp;
+}
+
+static void recv_errqueue_msgs(int fdt)
+{
+       struct pollfd pfd = { .fd = fdt, .events = POLLERR };
+       const int timeout_ms = 10;
+       int ret, num_tstamp = 0;
+
+       do {
+               ret = poll(&pfd, 1, timeout_ms);
+               if (ret == -1)
+                       error(1, errno, "poll");
+
+               if (ret && (pfd.revents & POLLERR))
+                       num_tstamp += do_recv_errqueue_timeout(fdt);
+
+               if (num_tstamp == cfg_num_pkt)
+                       break;
+
+       } while (gettime_ns(cfg_clockid) < tdeliver_max);
+}
+
+static void start_time_wait(void)
+{
+       uint64_t now;
+       int err;
+
+       if (!cfg_start_time_ns)
+               return;
+
+       now = gettime_ns(CLOCK_REALTIME);
+       if (cfg_start_time_ns < now)
+               return;
+
+       err = usleep((cfg_start_time_ns - now) / 1000);
+       if (err)
+               error(1, errno, "usleep");

 }
 
 static void setsockopt_txtime(int fd)
 }
 
 static void setsockopt_txtime(int fd)


@@ -245,6 +294,10 @@ static int setup_tx(struct sockaddr *addr, socklen_t alen)
 
        setsockopt_txtime(fd);
 
 
        setsockopt_txtime(fd);
 

+       if (cfg_mark &&
+           setsockopt(fd, SOL_SOCKET, SO_MARK, &cfg_mark, sizeof(cfg_mark)))
+               error(1, errno, "setsockopt mark");
+

        return fd;
 }
 
        return fd;
 }
 


@@ -266,31 +319,70 @@ static int setup_rx(struct sockaddr *addr, socklen_t alen)
        return fd;
 }
 
        return fd;
 }
 

-static void do_test(struct sockaddr *addr, socklen_t alen)
+static void do_test_tx(struct sockaddr *addr, socklen_t alen)

 {
 {

-       int fdt, fdr, i;
+       int fdt, i;

 
        fprintf(stderr, "\nSO_TXTIME ipv%c clock %s\n",
                        addr->sa_family == PF_INET ? '4' : '6',
                        cfg_clockid == CLOCK_TAI ? "tai" : "monotonic");
 
        fdt = setup_tx(addr, alen);
 
        fprintf(stderr, "\nSO_TXTIME ipv%c clock %s\n",
                        addr->sa_family == PF_INET ? '4' : '6',
                        cfg_clockid == CLOCK_TAI ? "tai" : "monotonic");
 
        fdt = setup_tx(addr, alen);

-       fdr = setup_rx(addr, alen);

 
 

-       glob_tstart = gettime_ns();
+       start_time_wait();
+       glob_tstart = gettime_ns(cfg_clockid);

 
        for (i = 0; i < cfg_num_pkt; i++)
 
        for (i = 0; i < cfg_num_pkt; i++)

-               do_send_one(fdt, &cfg_in[i]);
+               do_send_one(fdt, &cfg_buf[i]);
+
+       recv_errqueue_msgs(fdt);
+
+       if (close(fdt))
+               error(1, errno, "close t");
+}
+
+static void do_test_rx(struct sockaddr *addr, socklen_t alen)
+{
+       int fdr, i;
+
+       fdr = setup_rx(addr, alen);
+
+       start_time_wait();
+       glob_tstart = gettime_ns(cfg_clockid);
+

        for (i = 0; i < cfg_num_pkt; i++)
        for (i = 0; i < cfg_num_pkt; i++)

-               if (do_recv_one(fdr, &cfg_out[i]))
-                       do_recv_errqueue_timeout(fdt);
+               do_recv_one(fdr, &cfg_buf[i]);

 
        do_recv_verify_empty(fdr);
 
        if (close(fdr))
                error(1, errno, "close r");
 
        do_recv_verify_empty(fdr);
 
        if (close(fdr))
                error(1, errno, "close r");

-       if (close(fdt))
-               error(1, errno, "close t");
+}
+
+static void setup_sockaddr(int domain, const char *str_addr,
+                          struct sockaddr_storage *sockaddr)
+{
+       struct sockaddr_in6 *addr6 = (void *) sockaddr;
+       struct sockaddr_in *addr4 = (void *) sockaddr;
+
+       switch (domain) {
+       case PF_INET:
+               memset(addr4, 0, sizeof(*addr4));
+               addr4->sin_family = AF_INET;
+               addr4->sin_port = htons(cfg_port);
+               if (str_addr &&
+                   inet_pton(AF_INET, str_addr, &(addr4->sin_addr)) != 1)
+                       error(1, 0, "ipv4 parse error: %s", str_addr);
+               break;
+       case PF_INET6:
+               memset(addr6, 0, sizeof(*addr6));
+               addr6->sin6_family = AF_INET6;
+               addr6->sin6_port = htons(cfg_port);
+               if (str_addr &&
+                   inet_pton(AF_INET6, str_addr, &(addr6->sin6_addr)) != 1)
+                       error(1, 0, "ipv6 parse error: %s", str_addr);
+               break;
+       }

 }
 
 static int parse_io(const char *optarg, struct timed_send *array)
 }
 
 static int parse_io(const char *optarg, struct timed_send *array)


@@ -323,17 +415,46 @@ static int parse_io(const char *optarg, struct timed_send *array)
        return aoff / 2;
 }
 
        return aoff / 2;
 }
 

+static void usage(const char *progname)
+{
+       fprintf(stderr, "\nUsage: %s [options] <payload>\n"
+                       "Options:\n"
+                       "  -4            only IPv4\n"
+                       "  -6            only IPv6\n"
+                       "  -c <clock>    monotonic (default) or tai\n"
+                       "  -D <addr>     destination IP address (server)\n"
+                       "  -S <addr>     source IP address (client)\n"
+                       "  -r            run rx mode\n"
+                       "  -t <nsec>     start time (UTC nanoseconds)\n"
+                       "  -m <mark>     socket mark\n"
+                       "\n",
+                       progname);
+       exit(1);
+}
+

 static void parse_opts(int argc, char **argv)
 {
 static void parse_opts(int argc, char **argv)
 {

-       int c, ilen, olen;
+       char *daddr = NULL, *saddr = NULL;
+       int domain = PF_UNSPEC;
+       int c;

 
 

-       while ((c = getopt(argc, argv, "46c:")) != -1) {
+       while ((c = getopt(argc, argv, "46c:S:D:rt:m:")) != -1) {

                switch (c) {
                case '4':
                switch (c) {
                case '4':

-                       cfg_do_ipv4 = true;
+                       if (domain != PF_UNSPEC)
+                               error(1, 0, "Pass one of -4 or -6");
+                       domain = PF_INET;
+                       cfg_alen = sizeof(struct sockaddr_in);
+                       cfg_errq_level = SOL_IP;
+                       cfg_errq_type = IP_RECVERR;

                        break;
                case '6':
                        break;
                case '6':

-                       cfg_do_ipv6 = true;
+                       if (domain != PF_UNSPEC)
+                               error(1, 0, "Pass one of -4 or -6");
+                       domain = PF_INET6;
+                       cfg_alen = sizeof(struct sockaddr_in6);
+                       cfg_errq_level = SOL_IPV6;
+                       cfg_errq_type = IPV6_RECVERR;

                        break;
                case 'c':
                        if (!strcmp(optarg, "tai"))
                        break;
                case 'c':
                        if (!strcmp(optarg, "tai"))


@@ -344,50 +465,50 @@ static void parse_opts(int argc, char **argv)
                        else
                                error(1, 0, "unknown clock id %s", optarg);
                        break;
                        else
                                error(1, 0, "unknown clock id %s", optarg);
                        break;

+               case 'S':
+                       saddr = optarg;
+                       break;
+               case 'D':
+                       daddr = optarg;
+                       break;
+               case 'r':
+                       cfg_rx = true;
+                       break;
+               case 't':
+                       cfg_start_time_ns = strtol(optarg, NULL, 0);
+                       break;
+               case 'm':
+                       cfg_mark = strtol(optarg, NULL, 0);
+                       break;

                default:
                default:

-                       error(1, 0, "parse error at %d", optind);
+                       usage(argv[0]);

                }
        }
 
                }
        }
 

-       if (argc - optind != 2)
-               error(1, 0, "Usage: %s [-46] -c <clock> <in> <out>", argv[0]);
+       if (argc - optind != 1)
+               usage(argv[0]);
+
+       if (domain == PF_UNSPEC)
+               error(1, 0, "Pass one of -4 or -6");
+       if (!daddr)
+               error(1, 0, "-D <server addr> required\n");
+       if (!cfg_rx && !saddr)
+               error(1, 0, "-S <client addr> required\n");

 
 

-       ilen = parse_io(argv[optind], cfg_in);
-       olen = parse_io(argv[optind + 1], cfg_out);
-       if (ilen != olen)
-               error(1, 0, "i/o streams len mismatch (%d, %d)\n", ilen, olen);
-       cfg_num_pkt = ilen;
+       setup_sockaddr(domain, daddr, &cfg_dst_addr);
+       setup_sockaddr(domain, saddr, &cfg_src_addr);
+
+       cfg_num_pkt = parse_io(argv[optind], cfg_buf);

 }
 
 int main(int argc, char **argv)
 {
        parse_opts(argc, argv);
 
 }
 
 int main(int argc, char **argv)
 {
        parse_opts(argc, argv);
 

-       if (cfg_do_ipv6) {
-               struct sockaddr_in6 addr6 = {0};
-
-               addr6.sin6_family = AF_INET6;
-               addr6.sin6_port = htons(cfg_port);
-               addr6.sin6_addr = in6addr_loopback;
-
-               cfg_errq_level = SOL_IPV6;
-               cfg_errq_type = IPV6_RECVERR;
-
-               do_test((void *)&addr6, sizeof(addr6));
-       }
-
-       if (cfg_do_ipv4) {
-               struct sockaddr_in addr4 = {0};
-
-               addr4.sin_family = AF_INET;
-               addr4.sin_port = htons(cfg_port);
-               addr4.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
-
-               cfg_errq_level = SOL_IP;
-               cfg_errq_type = IP_RECVERR;
-
-               do_test((void *)&addr4, sizeof(addr4));
-       }
+       if (cfg_rx)
+               do_test_rx((void *)&cfg_dst_addr, cfg_alen);
+       else
+               do_test_tx((void *)&cfg_src_addr, cfg_alen);

 
        return 0;
 }
 
        return 0;
 }

diff --git a/tools/testing/selftests/net/so_txtime.sh b/tools/testing/selftests/net/so_txtime.sh
index 3f7800eaecb1e427e5b56d2087540355041397cc..3f06f4d286a988f15ccbc006f8015b24a07be3f0 100755 (executable)
--- a/tools/testing/selftests/net/so_txtime.sh
+++ b/tools/testing/selftests/net/so_txtime.sh
@@ -3,32 +3,85 @@
 #
 # Regression tests for the SO_TXTIME interface
 
 #
 # Regression tests for the SO_TXTIME interface
 

-# Run in network namespace
-if [[ $# -eq 0 ]]; then
-       if ! ./in_netns.sh $0 __subprocess; then
-               # test is time sensitive, can be flaky
-               echo "test failed: retry once"
-               ./in_netns.sh $0 __subprocess
+set -e
+
+readonly DEV="veth0"
+readonly BIN="./so_txtime"
+
+readonly RAND="$(mktemp -u XXXXXX)"
+readonly NSPREFIX="ns-${RAND}"
+readonly NS1="${NSPREFIX}1"
+readonly NS2="${NSPREFIX}2"
+
+readonly SADDR4='192.168.1.1'
+readonly DADDR4='192.168.1.2'
+readonly SADDR6='fd::1'
+readonly DADDR6='fd::2'
+
+cleanup() {
+       ip netns del "${NS2}"
+       ip netns del "${NS1}"
+}
+
+trap cleanup EXIT
+
+# Create virtual ethernet pair between network namespaces
+ip netns add "${NS1}"
+ip netns add "${NS2}"
+
+ip link add "${DEV}" netns "${NS1}" type veth \
+  peer name "${DEV}" netns "${NS2}"
+
+# Bring the devices up
+ip -netns "${NS1}" link set "${DEV}" up
+ip -netns "${NS2}" link set "${DEV}" up
+
+# Set fixed MAC addresses on the devices
+ip -netns "${NS1}" link set dev "${DEV}" address 02:02:02:02:02:02
+ip -netns "${NS2}" link set dev "${DEV}" address 06:06:06:06:06:06
+
+# Add fixed IP addresses to the devices
+ip -netns "${NS1}" addr add 192.168.1.1/24 dev "${DEV}"
+ip -netns "${NS2}" addr add 192.168.1.2/24 dev "${DEV}"
+ip -netns "${NS1}" addr add       fd::1/64 dev "${DEV}" nodad
+ip -netns "${NS2}" addr add       fd::2/64 dev "${DEV}" nodad
+
+do_test() {
+       local readonly IP="$1"
+       local readonly CLOCK="$2"
+       local readonly TXARGS="$3"
+       local readonly RXARGS="$4"
+
+       if [[ "${IP}" == "4" ]]; then
+               local readonly SADDR="${SADDR4}"
+               local readonly DADDR="${DADDR4}"
+       elif [[ "${IP}" == "6" ]]; then
+               local readonly SADDR="${SADDR6}"
+               local readonly DADDR="${DADDR6}"
+       else
+               echo "Invalid IP version ${IP}"
+               exit 1

        fi
 
        fi
 

-       exit $?
-fi
+       local readonly START="$(date +%s%N --date="+ 0.1 seconds")"
+       ip netns exec "${NS2}" "${BIN}" -"${IP}" -c "${CLOCK}" -t "${START}" -S "${SADDR}" -D "${DADDR}" "${RXARGS}" -r &
+       ip netns exec "${NS1}" "${BIN}" -"${IP}" -c "${CLOCK}" -t "${START}" -S "${SADDR}" -D "${DADDR}" "${TXARGS}"
+       wait "$!"
+}

 
 

-set -e
+ip netns exec "${NS1}" tc qdisc add dev "${DEV}" root fq
+do_test 4 mono a,-1 a,-1
+do_test 6 mono a,0 a,0
+do_test 6 mono a,10 a,10
+do_test 4 mono a,10,b,20 a,10,b,20
+do_test 6 mono a,20,b,10 b,20,a,20

 
 

-tc qdisc add dev lo root fq
-./so_txtime -4 -6 -c mono a,-1 a,-1
-./so_txtime -4 -6 -c mono a,0 a,0
-./so_txtime -4 -6 -c mono a,10 a,10
-./so_txtime -4 -6 -c mono a,10,b,20 a,10,b,20
-./so_txtime -4 -6 -c mono a,20,b,10 b,20,a,20
-
-if tc qdisc replace dev lo root etf clockid CLOCK_TAI delta 400000; then
-       ! ./so_txtime -4 -6 -c tai a,-1 a,-1
-       ! ./so_txtime -4 -6 -c tai a,0 a,0
-       ./so_txtime -4 -6 -c tai a,10 a,10
-       ./so_txtime -4 -6 -c tai a,10,b,20 a,10,b,20
-       ./so_txtime -4 -6 -c tai a,20,b,10 b,10,a,20
+if ip netns exec "${NS1}" tc qdisc replace dev "${DEV}" root etf clockid CLOCK_TAI delta 400000; then
+       ! do_test 4 tai a,-1 a,-1
+       ! do_test 6 tai a,0 a,0
+       do_test 6 tai a,10 a,10
+       do_test 4 tai a,10,b,20 a,10,b,20
+       do_test 6 tai a,20,b,10 b,10,a,20

 else
        echo "tc ($(tc -V)) does not support qdisc etf. skipping"
 fi
 else
        echo "tc ($(tc -V)) does not support qdisc etf. skipping"
 fi