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net: fix psock_fanout selftest hash collision
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Fix flaky results with PACKET_FANOUT_HASH depending on whether the
two flows hash into the same packet socket or not.

Also adds tests for PACKET_FANOUT_LB and PACKET_FANOUT_CPU and
replaces the counting method with a packet ring.

Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Willem de Bruijn authored and David S. Miller committed Mar 20, 2013
1 parent b44540e commit 23a9072
Showing 1 changed file with 120 additions and 40 deletions.
160 changes: 120 additions & 40 deletions tools/testing/selftests/net-afpacket/psock_fanout.c
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Original file line number Diff line number Diff line change
Expand Up @@ -16,11 +16,11 @@
* The test currently runs for
* - PACKET_FANOUT_HASH
* - PACKET_FANOUT_HASH with PACKET_FANOUT_FLAG_ROLLOVER
* - PACKET_FANOUT_LB
* - PACKET_FANOUT_CPU
* - PACKET_FANOUT_ROLLOVER
*
* Todo:
* - datapath: PACKET_FANOUT_LB
* - datapath: PACKET_FANOUT_CPU
* - functionality: PACKET_FANOUT_FLAG_DEFRAG
*
* License (GPLv2):
Expand All @@ -39,25 +39,32 @@
* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
*/

#define _GNU_SOURCE /* for sched_setaffinity */

#include <arpa/inet.h>
#include <errno.h>
#include <fcntl.h>
#include <linux/filter.h>
#include <linux/if_packet.h>
#include <net/ethernet.h>
#include <netinet/ip.h>
#include <netinet/udp.h>
#include <fcntl.h>
#include <poll.h>
#include <sched.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

#define DATA_LEN 100
#define DATA_CHAR 'a'
#define RING_NUM_FRAMES 20
#define PORT_BASE 8000

static void pair_udp_open(int fds[], uint16_t port)
{
Expand Down Expand Up @@ -162,46 +169,66 @@ static int sock_fanout_open(uint16_t typeflags, int num_packets)
return -1;
}

val = sizeof(struct iphdr) + sizeof(struct udphdr) + DATA_LEN;
val *= num_packets;
/* hack: apparently, the above calculation is too small (TODO: fix) */
val *= 3;
if (setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &val, sizeof(val))) {
perror("setsockopt SO_RCVBUF");
exit(1);
}

sock_fanout_setfilter(fd);
return fd;
}

static void sock_fanout_read(int fds[], const int expect[])
static char *sock_fanout_open_ring(int fd)
{
struct tpacket_stats stats;
socklen_t ssize;
int ret[2];
struct tpacket_req req = {
.tp_block_size = getpagesize(),
.tp_frame_size = getpagesize(),
.tp_block_nr = RING_NUM_FRAMES,
.tp_frame_nr = RING_NUM_FRAMES,
};
char *ring;

ssize = sizeof(stats);
if (getsockopt(fds[0], SOL_PACKET, PACKET_STATISTICS, &stats, &ssize)) {
perror("getsockopt statistics 0");
if (setsockopt(fd, SOL_PACKET, PACKET_RX_RING, (void *) &req,
sizeof(req))) {
perror("packetsock ring setsockopt");
exit(1);
}
ret[0] = stats.tp_packets - stats.tp_drops;
ssize = sizeof(stats);
if (getsockopt(fds[1], SOL_PACKET, PACKET_STATISTICS, &stats, &ssize)) {
perror("getsockopt statistics 1");

ring = mmap(0, req.tp_block_size * req.tp_block_nr,
PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (!ring) {
fprintf(stderr, "packetsock ring mmap\n");
exit(1);
}
ret[1] = stats.tp_packets - stats.tp_drops;

return ring;
}

static int sock_fanout_read_ring(int fd, void *ring)
{
struct tpacket_hdr *header = ring;
int count = 0;

while (header->tp_status & TP_STATUS_USER && count < RING_NUM_FRAMES) {
count++;
header = ring + (count * getpagesize());
}

return count;
}

static int sock_fanout_read(int fds[], char *rings[], const int expect[])
{
int ret[2];

ret[0] = sock_fanout_read_ring(fds[0], rings[0]);
ret[1] = sock_fanout_read_ring(fds[1], rings[1]);

fprintf(stderr, "info: count=%d,%d, expect=%d,%d\n",
ret[0], ret[1], expect[0], expect[1]);

if ((!(ret[0] == expect[0] && ret[1] == expect[1])) &&
(!(ret[0] == expect[1] && ret[1] == expect[0]))) {
fprintf(stderr, "ERROR: incorrect queue lengths\n");
exit(1);
return 1;
}

return 0;
}

/* Test illegal mode + flag combination */
Expand Down Expand Up @@ -253,11 +280,12 @@ static void test_control_group(void)
}
}

static void test_datapath(uint16_t typeflags,
const int expect1[], const int expect2[])
static int test_datapath(uint16_t typeflags, int port_off,
const int expect1[], const int expect2[])
{
const int expect0[] = { 0, 0 };
int fds[2], fds_udp[2][2];
char *rings[2];
int fds[2], fds_udp[2][2], ret;

fprintf(stderr, "test: datapath 0x%hx\n", typeflags);

Expand All @@ -267,41 +295,93 @@ static void test_datapath(uint16_t typeflags,
fprintf(stderr, "ERROR: failed open\n");
exit(1);
}
pair_udp_open(fds_udp[0], 8000);
pair_udp_open(fds_udp[1], 8002);
sock_fanout_read(fds, expect0);
rings[0] = sock_fanout_open_ring(fds[0]);
rings[1] = sock_fanout_open_ring(fds[1]);
pair_udp_open(fds_udp[0], PORT_BASE);
pair_udp_open(fds_udp[1], PORT_BASE + port_off);
sock_fanout_read(fds, rings, expect0);

/* Send data, but not enough to overflow a queue */
pair_udp_send(fds_udp[0], 15);
pair_udp_send(fds_udp[1], 5);
sock_fanout_read(fds, expect1);
ret = sock_fanout_read(fds, rings, expect1);

/* Send more data, overflow the queue */
pair_udp_send(fds_udp[0], 15);
/* TODO: ensure consistent order between expect1 and expect2 */
sock_fanout_read(fds, expect2);
ret |= sock_fanout_read(fds, rings, expect2);

if (munmap(rings[1], RING_NUM_FRAMES * getpagesize()) ||
munmap(rings[0], RING_NUM_FRAMES * getpagesize())) {
fprintf(stderr, "close rings\n");
exit(1);
}
if (close(fds_udp[1][1]) || close(fds_udp[1][0]) ||
close(fds_udp[0][1]) || close(fds_udp[0][0]) ||
close(fds[1]) || close(fds[0])) {
fprintf(stderr, "close datapath\n");
exit(1);
}

return ret;
}

static int set_cpuaffinity(int cpuid)
{
cpu_set_t mask;

CPU_ZERO(&mask);
CPU_SET(cpuid, &mask);
if (sched_setaffinity(0, sizeof(mask), &mask)) {
if (errno != EINVAL) {
fprintf(stderr, "setaffinity %d\n", cpuid);
exit(1);
}
return 1;
}

return 0;
}

int main(int argc, char **argv)
{
const int expect_hash[2][2] = { { 15, 5 }, { 5, 0 } };
const int expect_hash_rb[2][2] = { { 15, 5 }, { 5, 10 } };
const int expect_rb[2][2] = { { 20, 0 }, { 0, 15 } };
const int expect_hash[2][2] = { { 15, 5 }, { 20, 5 } };
const int expect_hash_rb[2][2] = { { 15, 5 }, { 20, 15 } };
const int expect_lb[2][2] = { { 10, 10 }, { 18, 17 } };
const int expect_rb[2][2] = { { 20, 0 }, { 20, 15 } };
const int expect_cpu0[2][2] = { { 20, 0 }, { 20, 0 } };
const int expect_cpu1[2][2] = { { 0, 20 }, { 0, 20 } };
int port_off = 2, tries = 5, ret;

test_control_single();
test_control_group();

test_datapath(PACKET_FANOUT_HASH, expect_hash[0], expect_hash[1]);
test_datapath(PACKET_FANOUT_HASH | PACKET_FANOUT_FLAG_ROLLOVER,
expect_hash_rb[0], expect_hash_rb[1]);
test_datapath(PACKET_FANOUT_ROLLOVER, expect_rb[0], expect_rb[1]);
/* find a set of ports that do not collide onto the same socket */
ret = test_datapath(PACKET_FANOUT_HASH, port_off,
expect_hash[0], expect_hash[1]);
while (ret && tries--) {
fprintf(stderr, "info: trying alternate ports (%d)\n", tries);
ret = test_datapath(PACKET_FANOUT_HASH, ++port_off,
expect_hash[0], expect_hash[1]);
}

ret |= test_datapath(PACKET_FANOUT_HASH | PACKET_FANOUT_FLAG_ROLLOVER,
port_off, expect_hash_rb[0], expect_hash_rb[1]);
ret |= test_datapath(PACKET_FANOUT_LB,
port_off, expect_lb[0], expect_lb[1]);
ret |= test_datapath(PACKET_FANOUT_ROLLOVER,
port_off, expect_rb[0], expect_rb[1]);

set_cpuaffinity(0);
ret |= test_datapath(PACKET_FANOUT_CPU, port_off,
expect_cpu0[0], expect_cpu0[1]);
if (!set_cpuaffinity(1))
/* TODO: test that choice alternates with previous */
ret |= test_datapath(PACKET_FANOUT_CPU, port_off,
expect_cpu1[0], expect_cpu1[1]);

if (ret)
return 1;

printf("OK. All tests passed\n");
return 0;
Expand Down

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