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Merge branch 'net-af_packet-allow-joining-a-fanout-when-link-is-down'

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Gur Stavi says:

====================
net: af_packet: allow joining a fanout when link is down

PACKET socket can retain its fanout membership through link down and up
and leave a fanout while closed regardless of link state.
However, socket was forbidden from joining a fanout while it was not
RUNNING.

This scenario was identified while studying DPDK pmd_af_packet_drv.
Since sockets are only created during initialization, there is no reason
to fail the initialization if a single link is temporarily down.

This patch allows PACKET socket to join a fanout while not RUNNING.

Selftest psock_fanout is extended to test this "fanout while link down"
scenario.

Selftest psock_fanout is also extended to test fanout create/join by
socket that did not bind or specified a protocol, which carries an
implicit bind.

v3: https://lore.kernel.org/cover.1728555449.git.gur.stavi@huawei.com
v2: https://lore.kernel.org/cover.1728382839.git.gur.stavi@huawei.com
v1: https://lore.kernel.org/cover.1728303615.git.gur.stavi@huawei.com
====================

Link: https://patch.msgid.link/cover.1728802323.git.gur.stavi@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Jakub Kicinski 2024-10-15 09:52:39 -07:00
commit a581ed8194
2 changed files with 80 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
net/packet/af_packet.c
View File

@ -1846,21 +1846,22 @@ static int fanout_add(struct sock *sk, struct fanout_args *args)
err = -EINVAL;
spin_lock(&po->bind_lock);
if (packet_sock_flag(po, PACKET_SOCK_RUNNING) &&
if (po->num &&
match->type == type &&
match->prot_hook.type == po->prot_hook.type &&
match->prot_hook.dev == po->prot_hook.dev) {
err = -ENOSPC;
if (refcount_read(&match->sk_ref) < match->max_num_members) {
__dev_remove_pack(&po->prot_hook);
/* Paired with packet_setsockopt(PACKET_FANOUT_DATA) */
WRITE_ONCE(po->fanout, match);
po->rollover = rollover;
rollover = NULL;
refcount_set(&match->sk_ref, refcount_read(&match->sk_ref) + 1);
__fanout_link(sk, po);
if (packet_sock_flag(po, PACKET_SOCK_RUNNING)) {
__dev_remove_pack(&po->prot_hook);
__fanout_link(sk, po);
}
err = 0;
}
}

78
tools/testing/selftests/net/psock_fanout.c
View File

@ -48,6 +48,7 @@
#include <string.h>
#include <sys/mman.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
@ -59,6 +60,33 @@
static uint32_t cfg_max_num_members;
static void loopback_set_up_down(int state_up)
{
struct ifreq ifreq = {};
int fd, err;
fd = socket(AF_PACKET, SOCK_RAW, 0);
if (fd < 0) {
perror("socket loopback");
exit(1);
}
strcpy(ifreq.ifr_name, "lo");
err = ioctl(fd, SIOCGIFFLAGS, &ifreq);
if (err) {
perror("SIOCGIFFLAGS");
exit(1);
}
if (state_up != !!(ifreq.ifr_flags & IFF_UP)) {
ifreq.ifr_flags ^= IFF_UP;
err = ioctl(fd, SIOCSIFFLAGS, &ifreq);
if (err) {
perror("SIOCSIFFLAGS");
exit(1);
}
}
close(fd);
}
/* Open a socket in a given fanout mode.
* @return -1 if mode is bad, a valid socket otherwise */
static int sock_fanout_open(uint16_t typeflags, uint16_t group_id)
@ -251,6 +279,41 @@ static int sock_fanout_read(int fds[], char *rings[], const int expect[])
return 0;
}
/* Test that creating/joining a fanout group fails for unbound socket without
* a specified protocol
*/
static void test_unbound_fanout(void)
{
int val, fd0, fd1, err;
fprintf(stderr, "test: unbound fanout\n");
fd0 = socket(PF_PACKET, SOCK_RAW, 0);
if (fd0 < 0) {
perror("socket packet");
exit(1);
}
/* Try to create a new fanout group. Should fail. */
val = (PACKET_FANOUT_HASH << 16) | 1;
err = setsockopt(fd0, SOL_PACKET, PACKET_FANOUT, &val, sizeof(val));
if (!err) {
fprintf(stderr, "ERROR: unbound socket fanout create\n");
exit(1);
}
fd1 = sock_fanout_open(PACKET_FANOUT_HASH, 1);
if (fd1 == -1) {
fprintf(stderr, "ERROR: failed to open HASH socket\n");
exit(1);
}
/* Try to join an existing fanout group. Should fail. */
err = setsockopt(fd0, SOL_PACKET, PACKET_FANOUT, &val, sizeof(val));
if (!err) {
fprintf(stderr, "ERROR: unbound socket fanout join\n");
exit(1);
}
close(fd0);
close(fd1);
}
/* Test illegal mode + flag combination */
static void test_control_single(void)
{
@ -264,17 +327,22 @@ static void test_control_single(void)
}
/* Test illegal group with different modes or flags */
static void test_control_group(void)
static void test_control_group(int toggle)
{
int fds[2];
fprintf(stderr, "test: control multiple sockets\n");
if (toggle)
fprintf(stderr, "test: control multiple sockets with link down toggle\n");
else
fprintf(stderr, "test: control multiple sockets\n");
fds[0] = sock_fanout_open(PACKET_FANOUT_HASH, 0);
if (fds[0] == -1) {
fprintf(stderr, "ERROR: failed to open HASH socket\n");
exit(1);
}
if (toggle)
loopback_set_up_down(0);
if (sock_fanout_open(PACKET_FANOUT_HASH |
PACKET_FANOUT_FLAG_DEFRAG, 0) != -1) {
fprintf(stderr, "ERROR: joined group with wrong flag defrag\n");
@ -294,6 +362,8 @@ static void test_control_group(void)
fprintf(stderr, "ERROR: failed to join group\n");
exit(1);
}
if (toggle)
loopback_set_up_down(1);
if (close(fds[1]) || close(fds[0])) {
fprintf(stderr, "ERROR: closing sockets\n");
exit(1);
@ -488,8 +558,10 @@ int main(int argc, char **argv)
const int expect_uniqueid[2][2] = { { 20, 20}, { 20, 20 } };
int port_off = 2, tries = 20, ret;
test_unbound_fanout();
test_control_single();
test_control_group();
test_control_group(0);
test_control_group(1);
test_control_group_max_num_members();
test_unique_fanout_group_ids();