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.
This is the only test that was performed.
Changes:
V04: * Minimized code change. * Removed test of ifindex. A socket that went through bind "unlisted" race can join a fanout.
V03: https://lore.kernel.org/netdev/cover.1728555449.git.gur.stavi@huawei.com * psock_fanout: add test for joining fanout with unbound socket. * Test that socket can receive packets before adding it to a fanout match. This is kind of replaces the RUNNING test that was removed. * Initialize po->ifindex in packet_create. To -1 if no protocol is specified and add an explicit initialization to 0 if protocol is specified. * Refactor relevant code in fanout_add within bind_lock, as a sequence of if {} else if {}, in order to reduce indentation of nested if statements and provide specific error codes.
V02: https://lore.kernel.org/netdev/cover.1728382839.git.gur.stavi@huawei.com * psock_fanout: use explicit loopback up/down instead of toggle. * psock_fanout: don't try to restore loopback state on failure. * Rephrase commit message about "leaving a fanout".
V01: https://lore.kernel.org/netdev/cover.1728303615.git.gur.stavi@huawei.com/
Gur Stavi (3): af_packet: allow fanout_add when socket is not RUNNING selftests: net/psock_fanout: socket joins fanout when link is down selftests: net/psock_fanout: unbound socket fanout
net/packet/af_packet.c | 9 +-- tools/testing/selftests/net/psock_fanout.c | 78 +++++++++++++++++++++- 2 files changed, 80 insertions(+), 7 deletions(-)
base-commit: c531f2269a53db5cf64b24baf785ccbcda52970f
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 patch allows PACKET socket to join fanout while not RUNNING.
Socket can be RUNNING if it has a specified protocol. Either directly from packet_create (being implicitly bound to any interface) or following a successful bind. Socket RUNNING state is switched off if it is bound to an interface that went down.
Instead of the test for RUNNING, this patch adds a test that socket can become RUNNING.
Signed-off-by: Gur Stavi gur.stavi@huawei.com --- net/packet/af_packet.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index f8942062f776..2ff4b251842d 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -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; } }
Gur Stavi wrote:
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 patch allows PACKET socket to join fanout while not RUNNING.
Socket can be RUNNING if it has a specified protocol. Either directly from packet_create (being implicitly bound to any interface) or following a successful bind. Socket RUNNING state is switched off if it is bound to an interface that went down.
Instead of the test for RUNNING, this patch adds a test that socket can become RUNNING.
Signed-off-by: Gur Stavi gur.stavi@huawei.com
Reviewed-by: Willem de Bruijn willemb@google.com
Modify test_control_group to have toggle parameter. When toggle is non-zero, loopback device will be set down for the initialization of fd[1] which is still expected to successfully join the fanout.
Signed-off-by: Gur Stavi gur.stavi@huawei.com --- tools/testing/selftests/net/psock_fanout.c | 42 ++++++++++++++++++++-- 1 file changed, 39 insertions(+), 3 deletions(-)
diff --git a/tools/testing/selftests/net/psock_fanout.c b/tools/testing/selftests/net/psock_fanout.c index 4f31e92ebd96..acdfae8f8a9a 100644 --- a/tools/testing/selftests/net/psock_fanout.c +++ b/tools/testing/selftests/net/psock_fanout.c @@ -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) @@ -264,17 +292,22 @@ 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 +327,8 @@ 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); @@ -489,7 +524,8 @@ int main(int argc, char **argv) int port_off = 2, tries = 20, ret;
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();
Gur Stavi wrote:
Modify test_control_group to have toggle parameter. When toggle is non-zero, loopback device will be set down for the initialization of fd[1] which is still expected to successfully join the fanout.
Signed-off-by: Gur Stavi gur.stavi@huawei.com
Reviewed-by: Willem de Bruijn willemb@google.com
Add a test that validates that an unbound packet socket cannot create/join a fanout group.
Signed-off-by: Gur Stavi gur.stavi@huawei.com --- tools/testing/selftests/net/psock_fanout.c | 36 ++++++++++++++++++++++ 1 file changed, 36 insertions(+)
diff --git a/tools/testing/selftests/net/psock_fanout.c b/tools/testing/selftests/net/psock_fanout.c index acdfae8f8a9a..84c524357075 100644 --- a/tools/testing/selftests/net/psock_fanout.c +++ b/tools/testing/selftests/net/psock_fanout.c @@ -279,6 +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) { @@ -523,6 +558,7 @@ 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(0); test_control_group(1);
Gur Stavi wrote:
Add a test that validates that an unbound packet socket cannot create/join a fanout group.
Signed-off-by: Gur Stavi gur.stavi@huawei.com
Reviewed-by: Willem de Bruijn willemb@google.com
Hello:
This series was applied to netdev/net-next.git (main) by Jakub Kicinski kuba@kernel.org:
On Sun, 13 Oct 2024 10:15:24 +0300 you wrote:
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.
[...]
Here is the summary with links: - [net-next,v04,1/3] af_packet: allow fanout_add when socket is not RUNNING https://git.kernel.org/netdev/net-next/c/2cee3e6e2e4b - [net-next,v04,2/3] selftests: net/psock_fanout: socket joins fanout when link is down https://git.kernel.org/netdev/net-next/c/9317e8933e27 - [net-next,v04,3/3] selftests: net/psock_fanout: unbound socket fanout https://git.kernel.org/netdev/net-next/c/7ec02a3aef05
You are awesome, thank you!
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