Merge branch 'selftests-fcnal'

Guillaume Nault says:

====================
selftests: fcnal: Test SO_DONTROUTE socket option.

The objective is to cover kernel paths that use the RTO_ONLINK flag
in .flowi4_tos. This way we'll be able to safely remove this flag in
the future by properly setting .flowi4_scope instead. With these
selftests in place, we can make sure this won't introduce regressions.

For more context, the final objective is to convert .flowi4_tos to
dscp_t, to ensure that ECN bits don't influence route and fib-rule
lookups (see commit a410a0cf9885 ("ipv6: Define dscp_t and stop taking
ECN bits into account in fib6-rules")).

These selftests only cover IPv4, as SO_DONTROUTE has no effect on IPv6
sockets.

v2:
  - Use two different nettest options for setting SO_DONTROUTE either
    on the server or on the client socket.

  - Use the above feature to run a single 'nettest -B' instance per
    test (instead of having two nettest processes for server and
    client).
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 132 insertions, 1 deletions

diff --git a/tools/testing/selftests/net/fcnal-test.sh b/tools/testing/selftests/net/fcnal-test.sh
index 21ca91473c09..05b5c4af7a08 100755
--- a/tools/testing/selftests/net/fcnal-test.sh
+++ b/tools/testing/selftests/net/fcnal-test.sh
@@ -585,6 +585,20 @@ ipv4_ping_novrf()
 	done
 
 	#
+	# out, but don't use gateway if peer is not on link
+	#
+	a=${NSB_IP}
+	log_start
+	run_cmd ping -c 1 -w 1 -r ${a}
+	log_test_addr ${a} $? 0 "ping out (don't route), peer on link"
+
+	a=${NSB_LO_IP}
+	log_start
+	show_hint "Fails since peer is not on link"
+	run_cmd ping -c 1 -w 1 -r ${a}
+	log_test_addr ${a} $? 1 "ping out (don't route), peer not on link"
+
+	#
 	# in
 	#
 	for a in ${NSA_IP} ${NSA_LO_IP}
@@ -1098,6 +1112,59 @@ test_ipv4_md5_vrf__global_server__bind_ifindex0()
 	set_sysctl net.ipv4.tcp_l3mdev_accept="$old_tcp_l3mdev_accept"
 }
 
+ipv4_tcp_dontroute()
+{
+	local syncookies=$1
+	local nsa_syncookies
+	local nsb_syncookies
+	local a
+
+	#
+	# Link local connection tests (SO_DONTROUTE).
+	# Connections should succeed only when the remote IP address is
+	# on link (doesn't need to be routed through a gateway).
+	#
+
+	nsa_syncookies=$(ip netns exec "${NSA}" sysctl -n net.ipv4.tcp_syncookies)
+	nsb_syncookies=$(ip netns exec "${NSB}" sysctl -n net.ipv4.tcp_syncookies)
+	ip netns exec "${NSA}" sysctl -wq net.ipv4.tcp_syncookies=${syncookies}
+	ip netns exec "${NSB}" sysctl -wq net.ipv4.tcp_syncookies=${syncookies}
+
+	# Test with eth1 address (on link).
+
+	a=${NSB_IP}
+	log_start
+	do_run_cmd nettest -B -N "${NSA}" -O "${NSB}" -r ${a} --client-dontroute
+	log_test_addr ${a} $? 0 "SO_DONTROUTE client, syncookies=${syncookies}"
+
+	a=${NSB_IP}
+	log_start
+	do_run_cmd nettest -B -N "${NSA}" -O "${NSB}" -r ${a} --server-dontroute
+	log_test_addr ${a} $? 0 "SO_DONTROUTE server, syncookies=${syncookies}"
+
+	# Test with loopback address (routed).
+	#
+	# The client would use the eth1 address as source IP by default.
+	# Therefore, we need to use the -c option here, to force the use of the
+	# routed (loopback) address as source IP (so that the server will try
+	# to respond to a routed address and not a link local one).
+
+	a=${NSB_LO_IP}
+	log_start
+	show_hint "Should fail 'Network is unreachable' since server is not on link"
+	do_run_cmd nettest -B -N "${NSA}" -O "${NSB}" -c "${NSA_LO_IP}" -r ${a} --client-dontroute
+	log_test_addr ${a} $? 1 "SO_DONTROUTE client, syncookies=${syncookies}"
+
+	a=${NSB_LO_IP}
+	log_start
+	show_hint "Should timeout since server cannot respond (client is not on link)"
+	do_run_cmd nettest -B -N "${NSA}" -O "${NSB}" -c "${NSA_LO_IP}" -r ${a} --server-dontroute
+	log_test_addr ${a} $? 2 "SO_DONTROUTE server, syncookies=${syncookies}"
+
+	ip netns exec "${NSB}" sysctl -wq net.ipv4.tcp_syncookies=${nsb_syncookies}
+	ip netns exec "${NSA}" sysctl -wq net.ipv4.tcp_syncookies=${nsa_syncookies}
+}
+
 ipv4_tcp_novrf()
 {
 	local a
@@ -1217,6 +1284,9 @@ ipv4_tcp_novrf()
 	log_test_addr ${a} $? 1 "No server, device client, local conn"
 
 	ipv4_tcp_md5_novrf
+
+	ipv4_tcp_dontroute 0
+	ipv4_tcp_dontroute 2
 }
 
 ipv4_tcp_vrf()
@@ -1585,6 +1655,23 @@ ipv4_udp_novrf()
 	log_start
 	run_cmd nettest -D -d ${NSA_DEV} -r ${a}
 	log_test_addr ${a} $? 2 "No server, device client, local conn"
+
+	#
+	# Link local connection tests (SO_DONTROUTE).
+	# Connections should succeed only when the remote IP address is
+	# on link (doesn't need to be routed through a gateway).
+	#
+
+	a=${NSB_IP}
+	log_start
+	do_run_cmd nettest -B -D -N "${NSA}" -O "${NSB}" -r ${a} --client-dontroute
+	log_test_addr ${a} $? 0 "SO_DONTROUTE client"
+
+	a=${NSB_LO_IP}
+	log_start
+	show_hint "Should fail 'Network is unreachable' since server is not on link"
+	do_run_cmd nettest -B -D -N "${NSA}" -O "${NSB}" -r ${a} --client-dontroute
+	log_test_addr ${a} $? 1 "SO_DONTROUTE client"
 }
 
 ipv4_udp_vrf()
diff --git a/tools/testing/selftests/net/nettest.c b/tools/testing/selftests/net/nettest.c
index ee9a72982705..39a0e01f8554 100644
--- a/tools/testing/selftests/net/nettest.c
+++ b/tools/testing/selftests/net/nettest.c
@@ -76,7 +76,9 @@ struct sock_args {
 		     has_grp:1,
 		     has_expected_laddr:1,
 		     has_expected_raddr:1,
-		     bind_test_only:1;
+		     bind_test_only:1,
+		     client_dontroute:1,
+		     server_dontroute:1;
 
 	unsigned short port;
 
@@ -611,6 +613,18 @@ static int set_dsfield(int sd, int version, int dsfield)
 	return 0;
 }
 
+static int set_dontroute(int sd)
+{
+	unsigned int one = 1;
+
+	if (setsockopt(sd, SOL_SOCKET, SO_DONTROUTE, &one, sizeof(one)) < 0) {
+		log_err_errno("setsockopt(SO_DONTROUTE)");
+		return -1;
+	}
+
+	return 0;
+}
+
 static int str_to_uint(const char *str, int min, int max, unsigned int *value)
 {
 	int number;
@@ -1351,6 +1365,14 @@ static int msock_init(struct sock_args *args, int server)
 	if (set_dsfield(sd, AF_INET, args->dsfield) != 0)
 		goto out_err;
 
+	if (server) {
+		if (args->server_dontroute && set_dontroute(sd) != 0)
+			goto out_err;
+	} else {
+		if (args->client_dontroute && set_dontroute(sd) != 0)
+			goto out_err;
+	}
+
 	if (args->dev && bind_to_device(sd, args->dev) != 0)
 		goto out_err;
 	else if (args->use_setsockopt &&
@@ -1482,6 +1504,9 @@ static int lsock_init(struct sock_args *args)
 	if (set_dsfield(sd, args->version, args->dsfield) != 0)
 		goto err;
 
+	if (args->server_dontroute && set_dontroute(sd) != 0)
+		goto err;
+
 	if (args->dev && bind_to_device(sd, args->dev) != 0)
 		goto err;
 	else if (args->use_setsockopt &&
@@ -1698,6 +1723,9 @@ static int connectsock(void *addr, socklen_t alen, struct sock_args *args)
 	if (set_dsfield(sd, args->version, args->dsfield) != 0)
 		goto err;
 
+	if (args->client_dontroute && set_dontroute(sd) != 0)
+		goto err;
+
 	if (args->dev && bind_to_device(sd, args->dev) != 0)
 		goto err;
 	else if (args->use_setsockopt &&
@@ -1905,10 +1933,14 @@ static int ipc_parent(int cpid, int fd, struct sock_args *args)
 #define GETOPT_STR  "sr:l:c:Q:p:t:g:P:DRn:M:X:m:d:I:BN:O:SUCi6xL:0:1:2:3:Fbqf"
 #define OPT_FORCE_BIND_KEY_IFINDEX 1001
 #define OPT_NO_BIND_KEY_IFINDEX 1002
+#define OPT_CLIENT_DONTROUTE 1003
+#define OPT_SERVER_DONTROUTE 1004
 
 static struct option long_opts[] = {
 	{"force-bind-key-ifindex", 0, 0, OPT_FORCE_BIND_KEY_IFINDEX},
 	{"no-bind-key-ifindex", 0, 0, OPT_NO_BIND_KEY_IFINDEX},
+	{"client-dontroute", 0, 0, OPT_CLIENT_DONTROUTE},
+	{"server-dontroute", 0, 0, OPT_SERVER_DONTROUTE},
 	{0, 0, 0, 0}
 };
 
@@ -1954,6 +1986,12 @@ static void print_usage(char *prog)
 	"    --no-bind-key-ifindex: Force TCP_MD5SIG_FLAG_IFINDEX off\n"
 	"    --force-bind-key-ifindex: Force TCP_MD5SIG_FLAG_IFINDEX on\n"
 	"        (default: only if -I is passed)\n"
+	"    --client-dontroute: don't use gateways for client socket: send\n"
+	"                        packets only if destination is on link (see\n"
+	"                        SO_DONTROUTE in socket(7))\n"
+	"    --server-dontroute: don't use gateways for server socket: send\n"
+	"                        packets only if destination is on link (see\n"
+	"                        SO_DONTROUTE in socket(7))\n"
 	"\n"
 	"    -g grp        multicast group (e.g., 239.1.1.1)\n"
 	"    -i            interactive mode (default is echo and terminate)\n"
@@ -2076,6 +2114,12 @@ int main(int argc, char *argv[])
 		case OPT_NO_BIND_KEY_IFINDEX:
 			args.bind_key_ifindex = -1;
 			break;
+		case OPT_CLIENT_DONTROUTE:
+			args.client_dontroute = 1;
+			break;
+		case OPT_SERVER_DONTROUTE:
+			args.server_dontroute = 1;
+			break;
 		case 'X':
 			args.client_pw = optarg;
 			break;