[PATCH net-next v3 7/8] selftest: tun: Add test for receiving gso packet from tun

[Xu Du <xudu@redhat.com>]

The test validate that GSO information are correctly exposed
when reading packets from a TUN device.

Signed-off-by: Xu Du <xudu@redhat.com>
---
v1 -> v2:
 - Use previous helper to simplify tunnel packet sending.
 - Treat read timeout (EAGAIN) as assertion failure.
 - Correct spelling of 'recieve' to 'receive'.

 tools/testing/selftests/net/tun.c | 194 ++++++++++++++++++++++++++++++
 1 file changed, 194 insertions(+)

diff --git a/tools/testing/selftests/net/tun.c b/tools/testing/selftests/net/tun.c
index dc114237adda..519aaffd6d1a 100644
--- a/tools/testing/selftests/net/tun.c
+++ b/tools/testing/selftests/net/tun.c
@@ -356,6 +356,116 @@ static int ip_route_check(const char *intf, int family, void *addr)
 	return 0;
 }
 
+static int send_gso_udp_msg(int socket, struct sockaddr_storage *addr,
+			    uint8_t *send_buf, int send_len, int gso_size)
+{
+	char control[CMSG_SPACE(sizeof(uint16_t))] = { 0 };
+	int alen = sockaddr_len(addr->ss_family);
+	struct msghdr msg = { 0 };
+	struct iovec iov = { 0 };
+	int ret;
+
+	iov.iov_base = send_buf;
+	iov.iov_len = send_len;
+
+	msg.msg_iov = &iov;
+	msg.msg_iovlen = 1;
+	msg.msg_name = addr;
+	msg.msg_namelen = alen;
+
+	if (gso_size > 0) {
+		struct cmsghdr *cmsg;
+
+		msg.msg_control = control;
+		msg.msg_controllen = sizeof(control);
+
+		cmsg = CMSG_FIRSTHDR(&msg);
+		cmsg->cmsg_level = SOL_UDP;
+		cmsg->cmsg_type = UDP_SEGMENT;
+		cmsg->cmsg_len = CMSG_LEN(sizeof(uint16_t));
+		*(uint16_t *)CMSG_DATA(cmsg) = gso_size;
+	}
+
+	ret = sendmsg(socket, &msg, 0);
+	if (ret < 0)
+		perror("sendmsg");
+
+	return ret;
+}
+
+static int validate_hdrlen(uint8_t **cur, int *len, int x)
+{
+	if (*len < x)
+		return -1;
+	*cur += x;
+	*len -= x;
+	return 0;
+}
+
+static int parse_udp_tunnel_vnet_packet(uint8_t *buf, int len, int tunnel_type,
+					bool is_tap)
+{
+	struct ipv6hdr *iph6;
+	struct udphdr *udph;
+	struct iphdr *iph4;
+	uint8_t *cur = buf;
+
+	if (validate_hdrlen(&cur, &len, TUN_VNET_TNL_SIZE))
+		return -1;
+
+	if (is_tap) {
+		if (validate_hdrlen(&cur, &len, ETH_HLEN))
+			return -1;
+	}
+
+	if (tunnel_type & UDP_TUNNEL_OUTER_IPV4) {
+		iph4 = (struct iphdr *)cur;
+		if (validate_hdrlen(&cur, &len, sizeof(struct iphdr)))
+			return -1;
+		if (iph4->version != 4 || iph4->protocol != IPPROTO_UDP)
+			return -1;
+	} else {
+		iph6 = (struct ipv6hdr *)cur;
+		if (validate_hdrlen(&cur, &len, sizeof(struct ipv6hdr)))
+			return -1;
+		if (iph6->version != 6 || iph6->nexthdr != IPPROTO_UDP)
+			return -1;
+	}
+
+	udph = (struct udphdr *)cur;
+	if (validate_hdrlen(&cur, &len, sizeof(struct udphdr)))
+		return -1;
+	if (ntohs(udph->dest) != VN_PORT)
+		return -1;
+
+	if (validate_hdrlen(&cur, &len, 8))
+		return -1;
+	if (validate_hdrlen(&cur, &len, ETH_HLEN))
+		return -1;
+
+	if (tunnel_type & UDP_TUNNEL_INNER_IPV4) {
+		iph4 = (struct iphdr *)cur;
+		if (validate_hdrlen(&cur, &len, sizeof(struct iphdr)))
+			return -1;
+		if (iph4->version != 4 || iph4->protocol != IPPROTO_UDP)
+			return -1;
+	} else {
+		iph6 = (struct ipv6hdr *)cur;
+		if (validate_hdrlen(&cur, &len, sizeof(struct ipv6hdr)))
+			return -1;
+		if (iph6->version != 6 || iph6->nexthdr != IPPROTO_UDP)
+			return -1;
+	}
+
+	udph = (struct udphdr *)cur;
+	if (validate_hdrlen(&cur, &len, sizeof(struct udphdr)))
+		return -1;
+	if (ntohs(udph->dest) != UDP_DST_PORT)
+		return -1;
+
+	return len;
+}
+
 FIXTURE(tun)
 {
 	char ifname[IFNAMSIZ];
@@ -683,6 +793,68 @@ receive_gso_packet_from_tunnel(FIXTURE_DATA(tun_vnet_udptnl) * self,
 	return total_len;
 }
 
+static int send_gso_packet_into_tunnel(FIXTURE_DATA(tun_vnet_udptnl) * self,
+				       const FIXTURE_VARIANT(tun_vnet_udptnl) *
+					       variant)
+{
+	int family = (variant->tunnel_type & UDP_TUNNEL_INNER_IPV4) ? AF_INET :
+								      AF_INET6;
+	uint8_t buf[MAX_VNET_TUNNEL_PACKET_SZ] = { 0 };
+	int payload_len = variant->data_size;
+	int gso_size = variant->gso_size;
+	struct sockaddr_storage ssa, dsa;
+
+	assign_sockaddr_vars(family, 0, &ssa, &dsa);
+	return send_gso_udp_msg(self->sock, &dsa, buf, payload_len, gso_size);
+}
+
+static int
+receive_gso_packet_from_tun(FIXTURE_DATA(tun_vnet_udptnl) * self,
+			    const FIXTURE_VARIANT(tun_vnet_udptnl) * variant,
+			    struct virtio_net_hdr_v1_hash_tunnel *vnet_hdr)
+{
+	struct timeval timeout = { .tv_sec = TIMEOUT_SEC };
+	uint8_t buf[MAX_VNET_TUNNEL_PACKET_SZ];
+	int tunnel_type = variant->tunnel_type;
+	int payload_len = variant->data_size;
+	bool is_tap = variant->is_tap;
+	int ret, len, total_len = 0;
+	int tun_fd = self->fd;
+	fd_set fdset;
+
+	while (total_len < payload_len) {
+		FD_ZERO(&fdset);
+		FD_SET(tun_fd, &fdset);
+
+		ret = select(tun_fd + 1, &fdset, NULL, NULL, &timeout);
+		if (ret <= 0) {
+			perror("select");
+			break;
+		}
+		if (!FD_ISSET(tun_fd, &fdset))
+			continue;
+
+		len = read(tun_fd, buf, sizeof(buf));
+		if (len <= 0) {
+			if (len < 0 && errno != EAGAIN && errno != EWOULDBLOCK)
+				perror("read");
+			break;
+		}
+
+		len = parse_udp_tunnel_vnet_packet(buf, len, tunnel_type,
+						   is_tap);
+		if (len < 0)
+			continue;
+
+		if (total_len == 0)
+			memcpy(vnet_hdr, buf, TUN_VNET_TNL_SIZE);
+
+		total_len += len;
+	}
+
+	return total_len;
+}
+
 TEST_F(tun_vnet_udptnl, send_gso_packet)
 {
 	uint8_t pkt[MAX_VNET_TUNNEL_PACKET_SZ];
@@ -699,4 +871,26 @@ TEST_F(tun_vnet_udptnl, send_gso_packet)
 	ASSERT_EQ(r_num_mss, variant->r_num_mss);
 }
 
+TEST_F(tun_vnet_udptnl, recv_gso_packet)
+{
+	struct virtio_net_hdr_v1_hash_tunnel vnet_hdr = { 0 };
+	struct virtio_net_hdr_v1 *vh = &vnet_hdr.hash_hdr.hdr;
+	int ret, gso_type = VIRTIO_NET_HDR_GSO_UDP_L4;
+
+	ret = send_gso_packet_into_tunnel(self, variant);
+	ASSERT_EQ(ret, variant->data_size);
+
+	memset(&vnet_hdr, 0, sizeof(vnet_hdr));
+	ret = receive_gso_packet_from_tun(self, variant, &vnet_hdr);
+	ASSERT_EQ(ret, variant->data_size);
+
+	if (!variant->no_gso) {
+		ASSERT_EQ(vh->gso_size, variant->gso_size);
+		gso_type |= (variant->tunnel_type & UDP_TUNNEL_OUTER_IPV4) ?
+				    (VIRTIO_NET_HDR_GSO_UDP_TUNNEL_IPV4) :
+				    (VIRTIO_NET_HDR_GSO_UDP_TUNNEL_IPV6);
+		ASSERT_EQ(vh->gso_type, gso_type);
+	}
+}
+
 TEST_HARNESS_MAIN
-- 
2.49.0