Add ping and iperf3 tests for ppp_async.c and pppoe.c.

Signed-off-by: Qingfang Deng <dqfext@gmail.com>
---
v7: repost after 24h
 https://lore.kernel.org/netdev/20260327033438.125135-1-dqfext@gmail.com/

 MAINTAINERS                                   |  1 +
 tools/testing/selftests/Makefile              |  1 +
 tools/testing/selftests/net/ppp/Makefile      | 15 +++++++
 tools/testing/selftests/net/ppp/config        |  9 ++++
 tools/testing/selftests/net/ppp/ppp_async.sh  | 44 +++++++++++++++++++
 tools/testing/selftests/net/ppp/ppp_common.sh | 44 +++++++++++++++++++
 .../selftests/net/ppp/pppoe-server-options    |  2 +
 tools/testing/selftests/net/ppp/pppoe.sh      | 41 +++++++++++++++++
 8 files changed, 157 insertions(+)
 create mode 100644 tools/testing/selftests/net/ppp/Makefile
 create mode 100644 tools/testing/selftests/net/ppp/config
 create mode 100755 tools/testing/selftests/net/ppp/ppp_async.sh
 create mode 100644 tools/testing/selftests/net/ppp/ppp_common.sh
 create mode 100644 tools/testing/selftests/net/ppp/pppoe-server-options
 create mode 100755 tools/testing/selftests/net/ppp/pppoe.sh

diff --git a/MAINTAINERS b/MAINTAINERS
index 7a2ffd9d37d5..b922e154b9e7 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -21080,6 +21080,7 @@ PPP PROTOCOL DRIVERS AND COMPRESSORS
 L:	linux-ppp@vger.kernel.org
 S:	Orphan
 F:	drivers/net/ppp/ppp_*
+F:	tools/testing/selftests/net/ppp/
 
 PPS SUPPORT
 M:	Rodolfo Giometti <giometti@enneenne.com>
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 450f13ba4cca..65f84e8a0cf0 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -78,6 +78,7 @@ TARGETS += net/netfilter
 TARGETS += net/openvswitch
 TARGETS += net/ovpn
 TARGETS += net/packetdrill
+TARGETS += net/ppp
 TARGETS += net/rds
 TARGETS += net/tcp_ao
 TARGETS += nolibc
diff --git a/tools/testing/selftests/net/ppp/Makefile b/tools/testing/selftests/net/ppp/Makefile
new file mode 100644
index 000000000000..b39b0abadde6
--- /dev/null
+++ b/tools/testing/selftests/net/ppp/Makefile
@@ -0,0 +1,15 @@
+# SPDX-License-Identifier: GPL-2.0
+
+top_srcdir = ../../../../..
+
+TEST_PROGS := \
+	ppp_async.sh \
+	pppoe.sh \
+# end of TEST_PROGS
+
+TEST_FILES := \
+	ppp_common.sh \
+	pppoe-server-options \
+# end of TEST_FILES
+
+include ../../lib.mk
diff --git a/tools/testing/selftests/net/ppp/config b/tools/testing/selftests/net/ppp/config
new file mode 100644
index 000000000000..b45d25c5b970
--- /dev/null
+++ b/tools/testing/selftests/net/ppp/config
@@ -0,0 +1,9 @@
+CONFIG_IPV6=y
+CONFIG_PACKET=y
+CONFIG_PPP=m
+CONFIG_PPP_ASYNC=m
+CONFIG_PPP_BSDCOMP=m
+CONFIG_PPP_DEFLATE=m
+CONFIG_PPPOE=m
+CONFIG_PPPOE_HASH_BITS_4=y
+CONFIG_VETH=y
diff --git a/tools/testing/selftests/net/ppp/ppp_async.sh b/tools/testing/selftests/net/ppp/ppp_async.sh
new file mode 100755
index 000000000000..9233dc656678
--- /dev/null
+++ b/tools/testing/selftests/net/ppp/ppp_async.sh
@@ -0,0 +1,44 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+source ppp_common.sh
+
+# Temporary files for PTY symlinks
+TTY_DIR=$(mktemp -d /tmp/ppp.XXXXXX)
+TTY_SERVER="$TTY_DIR"/server
+TTY_CLIENT="$TTY_DIR"/client
+
+# shellcheck disable=SC2329
+cleanup() {
+	cleanup_all_ns
+	[ -n "$SOCAT_PID" ] && kill_process "$SOCAT_PID"
+	rm -fr "$TTY_DIR"
+}
+
+trap cleanup EXIT
+
+require_command socat
+ppp_common_init
+modprobe -q ppp_async
+
+# Create the virtual serial device
+socat -d PTY,link="$TTY_SERVER",rawer PTY,link="$TTY_CLIENT",rawer &
+SOCAT_PID=$!
+
+# Wait for symlinks to be created
+slowwait 5 [ -L "$TTY_SERVER" ]
+
+# Start the PPP Server
+ip netns exec "$NS_SERVER" pppd "$TTY_SERVER" 115200 \
+	"$IP_SERVER":"$IP_CLIENT" \
+	local noauth nodefaultroute debug
+
+# Start the PPP Client
+ip netns exec "$NS_CLIENT" pppd "$TTY_CLIENT" 115200 \
+	local noauth updetach nodefaultroute debug
+
+ppp_test_connectivity
+
+log_test "PPP async"
+
+exit "$EXIT_STATUS"
diff --git a/tools/testing/selftests/net/ppp/ppp_common.sh b/tools/testing/selftests/net/ppp/ppp_common.sh
new file mode 100644
index 000000000000..c72218813f95
--- /dev/null
+++ b/tools/testing/selftests/net/ppp/ppp_common.sh
@@ -0,0 +1,44 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# shellcheck disable=SC2153
+
+source ../lib.sh
+
+IP_SERVER="192.168.200.1"
+IP_CLIENT="192.168.200.2"
+
+ppp_common_init() {
+	# Package requirements
+	require_command pppd
+	require_command iperf3
+
+	# Check for root privileges
+	if [ "$(id -u)" -ne 0 ];then
+		echo "SKIP: Need root privileges"
+		exit $ksft_skip
+	fi
+
+	# Namespaces
+	setup_ns NS_SERVER NS_CLIENT
+}
+
+ppp_check_addr() {
+	dev=$1
+	addr=$2
+	ns=$3
+	ip -netns "$ns" -4 addr show dev "$dev" 2>/dev/null | grep -q "$addr"
+	return $?
+}
+
+ppp_test_connectivity() {
+	slowwait 10 ppp_check_addr "ppp0" "$IP_CLIENT" "$NS_CLIENT"
+
+	ip netns exec "$NS_CLIENT" ping -c 3 "$IP_SERVER"
+	check_err $?
+
+	ip netns exec "$NS_SERVER" iperf3 -s -1 -D
+	wait_local_port_listen "$NS_SERVER" 5201 tcp
+
+	ip netns exec "$NS_CLIENT" iperf3 -c "$IP_SERVER" -Z -t 2
+	check_err $?
+}
diff --git a/tools/testing/selftests/net/ppp/pppoe-server-options b/tools/testing/selftests/net/ppp/pppoe-server-options
new file mode 100644
index 000000000000..66c8c9d319e9
--- /dev/null
+++ b/tools/testing/selftests/net/ppp/pppoe-server-options
@@ -0,0 +1,2 @@
+noauth
+noipdefault
diff --git a/tools/testing/selftests/net/ppp/pppoe.sh b/tools/testing/selftests/net/ppp/pppoe.sh
new file mode 100755
index 000000000000..73e4ea957b43
--- /dev/null
+++ b/tools/testing/selftests/net/ppp/pppoe.sh
@@ -0,0 +1,41 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+source ppp_common.sh
+
+VETH_SERVER="veth-server"
+VETH_CLIENT="veth-client"
+
+# shellcheck disable=SC2329
+cleanup() {
+	cleanup_all_ns
+}
+
+trap cleanup EXIT
+
+require_command pppoe-server
+ppp_common_init
+modprobe -q pppoe
+
+# Create the veth pair
+ip link add "$VETH_SERVER" type veth peer name "$VETH_CLIENT"
+ip link set "$VETH_SERVER" netns "$NS_SERVER"
+ip link set "$VETH_CLIENT" netns "$NS_CLIENT"
+ip -netns "$NS_SERVER" link set "$VETH_SERVER" up
+ip -netns "$NS_CLIENT" link set "$VETH_CLIENT" up
+
+# Start the PPP Server
+ip netns exec "$NS_SERVER" pppoe-server -I "$VETH_SERVER" \
+	-L "$IP_SERVER" -R "$IP_CLIENT" -N 1 -q "$(command -v pppd)" \
+	-k -O "$(pwd)/pppoe-server-options"
+
+# Start the PPP Client
+ip netns exec "$NS_CLIENT" pppd \
+	local debug updetach noipdefault noauth nodefaultroute \
+	plugin pppoe.so nic-"$VETH_CLIENT"
+
+ppp_test_connectivity
+
+log_test "PPPoE"
+
+exit "$EXIT_STATUS"
-- 
2.43.0

On Mon, 30 Mar 2026 11:55:44 +0800 Qingfang Deng wrote:
> Add ping and iperf3 tests for ppp_async.c and pppoe.c.

Hi! I added the new TARGET to netdev CI, the pppoe.sh test does not
seem happy:

# timeout set to 45
# selftests: net/ppp: pppoe.sh
# Plugin pppoe.so loaded.
# PPPoE plugin from pppd 2.5.1
# Send PPPOE Discovery V1T1 PADI session 0x0 length 12
#  dst ff:ff:ff:ff:ff:ff  src b2:36:d8:0d:61:83
#  [service-name] [host-uniq 9b 08 00 00]
# Recv PPPOE Discovery V1T1 PADO session 0x0 length 73
#  dst b2:36:d8:0d:61:83  src 4e:f5:66:23:13:38
#  [AC-name vmksft-net-extra,debug-threads=on] [service-name] [AC-cookie e5 e4 8c f0 87 72 d8 3a 60 66 4e 32 e4 ee af 6f 9a 08 00 00] [host-uniq 9b 08 00 00]
# Send PPPOE Discovery V1T1 PADR session 0x0 length 36
#  dst 4e:f5:66:23:13:38  src b2:36:d8:0d:61:83
#  [service-name] [host-uniq 9b 08 00 00] [AC-cookie e5 e4 8c f0 87 72 d8 3a 60 66 4e 32 e4 ee af 6f 9a 08 00 00]
# Recv PPPOE Discovery V1T1 PADS session 0x1 length 12
#  dst b2:36:d8:0d:61:83  src 4e:f5:66:23:13:38
#  [service-name] [host-uniq 9b 08 00 00]
# PPP session is 1
# Connected to 4E:F5:66:23:13:38 via interface veth-client
# using channel 1
# Using interface ppp0
# Connect: ppp0 <--> veth-client
# sent [LCP ConfReq id=0x1 <mru 1492> <magic 0x6db8fab4>]
# Modem hangup
# Connection terminated.
# Send PPPOE Discovery V1T1 PADT session 0x1 length 32
#  dst 4e:f5:66:23:13:38  src b2:36:d8:0d:61:83
#  [host-uniq 9b 08 00 00] [AC-cookie e5 e4 8c f0 87 72 d8 3a 60 66 4e 32 e4 ee af 6f 9a 08 00 00]
# Sent PADT
# ping: connect: Network is unreachable
# iperf3: error - unable to connect to server - server may have stopped running or use a different port, firewall issue, etc.: Network is unreachable
# TEST: PPPoE                                                         [FAIL]
not ok 1 selftests: net/ppp: pppoe.sh # exit=1

Hi,

On Wed, Apr 1, 2026 at 11:10 PM Jakub Kicinski <kuba@kernel.org> wrote:
>
> On Mon, 30 Mar 2026 11:55:44 +0800 Qingfang Deng wrote:
> > Add ping and iperf3 tests for ppp_async.c and pppoe.c.
>
> Hi! I added the new TARGET to netdev CI, the pppoe.sh test does not
> seem happy:
>
> # timeout set to 45
> # selftests: net/ppp: pppoe.sh
> # Plugin pppoe.so loaded.
> # PPPoE plugin from pppd 2.5.1
> # Send PPPOE Discovery V1T1 PADI session 0x0 length 12
> #  dst ff:ff:ff:ff:ff:ff  src b2:36:d8:0d:61:83
> #  [service-name] [host-uniq 9b 08 00 00]
> # Recv PPPOE Discovery V1T1 PADO session 0x0 length 73
> #  dst b2:36:d8:0d:61:83  src 4e:f5:66:23:13:38
> #  [AC-name vmksft-net-extra,debug-threads=on] [service-name] [AC-cookie e5 e4 8c f0 87 72 d8 3a 60 66 4e 32 e4 ee af 6f 9a 08 00 00] [host-uniq 9b 08 00 00]
> # Send PPPOE Discovery V1T1 PADR session 0x0 length 36
> #  dst 4e:f5:66:23:13:38  src b2:36:d8:0d:61:83
> #  [service-name] [host-uniq 9b 08 00 00] [AC-cookie e5 e4 8c f0 87 72 d8 3a 60 66 4e 32 e4 ee af 6f 9a 08 00 00]
> # Recv PPPOE Discovery V1T1 PADS session 0x1 length 12
> #  dst b2:36:d8:0d:61:83  src 4e:f5:66:23:13:38
> #  [service-name] [host-uniq 9b 08 00 00]
> # PPP session is 1
> # Connected to 4E:F5:66:23:13:38 via interface veth-client
> # using channel 1
> # Using interface ppp0
> # Connect: ppp0 <--> veth-client
> # sent [LCP ConfReq id=0x1 <mru 1492> <magic 0x6db8fab4>]
> # Modem hangup
> # Connection terminated.
> # Send PPPOE Discovery V1T1 PADT session 0x1 length 32
> #  dst 4e:f5:66:23:13:38  src b2:36:d8:0d:61:83
> #  [host-uniq 9b 08 00 00] [AC-cookie e5 e4 8c f0 87 72 d8 3a 60 66 4e 32 e4 ee af 6f 9a 08 00 00]
> # Sent PADT
> # ping: connect: Network is unreachable
> # iperf3: error - unable to connect to server - server may have stopped running or use a different port, firewall issue, etc.: Network is unreachable
> # TEST: PPPoE                                                         [FAIL]
> not ok 1 selftests: net/ppp: pppoe.sh # exit=1

It looks like pppoe-server fails to start. You may check the syslog to
see what's going on.

Regards,
Qingfang

On Wed, 1 Apr 2026 23:45:38 +0800 Qingfang Deng wrote:
> > # iperf3: error - unable to connect to server - server may have stopped running or use a different port, firewall issue, etc.: Network is unreachable
> > # TEST: PPPoE                                                         [FAIL]
> > not ok 1 selftests: net/ppp: pppoe.sh # exit=1  
> 
> It looks like pppoe-server fails to start. You may check the syslog to
> see what's going on.

Hm, we don't capture syslog automatically :S We capture stdout and
stderr

I'm not even sure there's something listening on syslog in virtme-ng
Is it possible to make the daemon log to stdout or a file and dump
that file to stdout on failure? Even if we fix the current issue
it will be quite inconvenient if we have to go into syslog every time
the test is failing. The test output should provide enough info to
debug failures.

Hi,

On Thu, Apr 2, 2026 at 8:56 AM Jakub Kicinski <kuba@kernel.org> wrote:
>
> On Wed, 1 Apr 2026 23:45:38 +0800 Qingfang Deng wrote:
> > > # iperf3: error - unable to connect to server - server may have stopped running or use a different port, firewall issue, etc.: Network is unreachable
> > > # TEST: PPPoE                                                         [FAIL]
> > > not ok 1 selftests: net/ppp: pppoe.sh # exit=1
> >
> > It looks like pppoe-server fails to start. You may check the syslog to
> > see what's going on.
>
> Hm, we don't capture syslog automatically :S We capture stdout and
> stderr
>
> I'm not even sure there's something listening on syslog in virtme-ng
> Is it possible to make the daemon log to stdout or a file and dump
> that file to stdout on failure? Even if we fix the current issue
> it will be quite inconvenient if we have to go into syslog every time
> the test is failing. The test output should provide enough info to
> debug failures.

Add Cc: Dianne

I checked the man page of pppoe-server and did not find such option.
We can instead start our own listener and redirect the syslog to a
file or stdout:

socat -u UNIX-RECV:/dev/log,ignoreeof STDOUT &

Regards,
Qingfang

On Thu, 2 Apr 2026 10:26:11 +0800 Qingfang Deng wrote:
> Hi,
> 
> On Thu, Apr 2, 2026 at 8:56 AM Jakub Kicinski <kuba@kernel.org> wrote:
> >
> > On Wed, 1 Apr 2026 23:45:38 +0800 Qingfang Deng wrote:  
>  [...]  
> > >
> > > It looks like pppoe-server fails to start. You may check the syslog to
> > > see what's going on.  
> >
> > Hm, we don't capture syslog automatically :S We capture stdout and
> > stderr
> >
> > I'm not even sure there's something listening on syslog in virtme-ng
> > Is it possible to make the daemon log to stdout or a file and dump
> > that file to stdout on failure? Even if we fix the current issue
> > it will be quite inconvenient if we have to go into syslog every time
> > the test is failing. The test output should provide enough info to
> > debug failures.  
> 
> Add Cc: Dianne
> 
> I checked the man page of pppoe-server and did not find such option.
> We can instead start our own listener and redirect the syslog to a
> file or stdout:
> 
> socat -u UNIX-RECV:/dev/log,ignoreeof STDOUT &

That should work for vng, I confirmed it doesn't seem to have a syslog
socket

$ vng -r
...
$ ls /dev/log
ls: cannot access '/dev/log': No such file or directory