1 files changed, 283 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/ip_check_defrag.c b/tools/testing/selftests/bpf/prog_tests/ip_check_defrag.c
new file mode 100644
index 000000000000..57c814f5f6a7
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/ip_check_defrag.c
@@ -0,0 +1,283 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <test_progs.h>
+#include <net/if.h>
+#include <linux/netfilter.h>
+#include <network_helpers.h>
+#include "ip_check_defrag.skel.h"
+#include "ip_check_defrag_frags.h"
+
+/*
+ * This selftest spins up a client and an echo server, each in their own
+ * network namespace. The client will send a fragmented message to the server.
+ * The prog attached to the server will shoot down any fragments. Thus, if
+ * the server is able to correctly echo back the message to the client, we will
+ * have verified that netfilter is reassembling packets for us.
+ *
+ * Topology:
+ * =========
+ *           NS0         |         NS1
+ *                       |
+ *         client        |       server
+ *       ----------      |     ----------
+ *       |  veth0  | --------- |  veth1  |
+ *       ----------    peer    ----------
+ *                       |
+ *                       |       with bpf
+ */
+
+#define NS0		"defrag_ns0"
+#define NS1		"defrag_ns1"
+#define VETH0		"veth0"
+#define VETH1		"veth1"
+#define VETH0_ADDR	"172.16.1.100"
+#define VETH0_ADDR6	"fc00::100"
+/* The following constants must stay in sync with `generate_udp_fragments.py` */
+#define VETH1_ADDR	"172.16.1.200"
+#define VETH1_ADDR6	"fc00::200"
+#define CLIENT_PORT	48878
+#define SERVER_PORT	48879
+#define MAGIC_MESSAGE	"THIS IS THE ORIGINAL MESSAGE, PLEASE REASSEMBLE ME"
+
+static int setup_topology(bool ipv6)
+{
+	bool up;
+	int i;
+
+	SYS(fail, "ip netns add " NS0);
+	SYS(fail, "ip netns add " NS1);
+	SYS(fail, "ip link add " VETH0 " netns " NS0 " type veth peer name " VETH1 " netns " NS1);
+	if (ipv6) {
+		SYS(fail, "ip -6 -net " NS0 " addr add " VETH0_ADDR6 "/64 dev " VETH0 " nodad");
+		SYS(fail, "ip -6 -net " NS1 " addr add " VETH1_ADDR6 "/64 dev " VETH1 " nodad");
+	} else {
+		SYS(fail, "ip -net " NS0 " addr add " VETH0_ADDR "/24 dev " VETH0);
+		SYS(fail, "ip -net " NS1 " addr add " VETH1_ADDR "/24 dev " VETH1);
+	}
+	SYS(fail, "ip -net " NS0 " link set dev " VETH0 " up");
+	SYS(fail, "ip -net " NS1 " link set dev " VETH1 " up");
+
+	/* Wait for up to 5s for links to come up */
+	for (i = 0; i < 5; ++i) {
+		if (ipv6)
+			up = !system("ip netns exec " NS0 " ping -6 -c 1 -W 1 " VETH1_ADDR6 " &>/dev/null");
+		else
+			up = !system("ip netns exec " NS0 " ping -c 1 -W 1 " VETH1_ADDR " &>/dev/null");
+
+		if (up)
+			break;
+	}
+
+	return 0;
+fail:
+	return -1;
+}
+
+static void cleanup_topology(void)
+{
+	SYS_NOFAIL("test -f /var/run/netns/" NS0 " && ip netns delete " NS0);
+	SYS_NOFAIL("test -f /var/run/netns/" NS1 " && ip netns delete " NS1);
+}
+
+static int attach(struct ip_check_defrag *skel, bool ipv6)
+{
+	LIBBPF_OPTS(bpf_netfilter_opts, opts,
+		    .pf = ipv6 ? NFPROTO_IPV6 : NFPROTO_IPV4,
+		    .priority = 42,
+		    .flags = BPF_F_NETFILTER_IP_DEFRAG);
+	struct nstoken *nstoken;
+	int err = -1;
+
+	nstoken = open_netns(NS1);
+
+	skel->links.defrag = bpf_program__attach_netfilter(skel->progs.defrag, &opts);
+	if (!ASSERT_OK_PTR(skel->links.defrag, "program attach"))
+		goto out;
+
+	err = 0;
+out:
+	close_netns(nstoken);
+	return err;
+}
+
+static int send_frags(int client)
+{
+	struct sockaddr_storage saddr;
+	struct sockaddr *saddr_p;
+	socklen_t saddr_len;
+	int err;
+
+	saddr_p = (struct sockaddr *)&saddr;
+	err = make_sockaddr(AF_INET, VETH1_ADDR, SERVER_PORT, &saddr, &saddr_len);
+	if (!ASSERT_OK(err, "make_sockaddr"))
+		return -1;
+
+	err = sendto(client, frag_0, sizeof(frag_0), 0, saddr_p, saddr_len);
+	if (!ASSERT_GE(err, 0, "sendto frag_0"))
+		return -1;
+
+	err = sendto(client, frag_1, sizeof(frag_1), 0, saddr_p, saddr_len);
+	if (!ASSERT_GE(err, 0, "sendto frag_1"))
+		return -1;
+
+	err = sendto(client, frag_2, sizeof(frag_2), 0, saddr_p, saddr_len);
+	if (!ASSERT_GE(err, 0, "sendto frag_2"))
+		return -1;
+
+	return 0;
+}
+
+static int send_frags6(int client)
+{
+	struct sockaddr_storage saddr;
+	struct sockaddr *saddr_p;
+	socklen_t saddr_len;
+	int err;
+
+	saddr_p = (struct sockaddr *)&saddr;
+	/* Port needs to be set to 0 for raw ipv6 socket for some reason */
+	err = make_sockaddr(AF_INET6, VETH1_ADDR6, 0, &saddr, &saddr_len);
+	if (!ASSERT_OK(err, "make_sockaddr"))
+		return -1;
+
+	err = sendto(client, frag6_0, sizeof(frag6_0), 0, saddr_p, saddr_len);
+	if (!ASSERT_GE(err, 0, "sendto frag6_0"))
+		return -1;
+
+	err = sendto(client, frag6_1, sizeof(frag6_1), 0, saddr_p, saddr_len);
+	if (!ASSERT_GE(err, 0, "sendto frag6_1"))
+		return -1;
+
+	err = sendto(client, frag6_2, sizeof(frag6_2), 0, saddr_p, saddr_len);
+	if (!ASSERT_GE(err, 0, "sendto frag6_2"))
+		return -1;
+
+	return 0;
+}
+
+void test_bpf_ip_check_defrag_ok(bool ipv6)
+{
+	struct network_helper_opts rx_opts = {
+		.timeout_ms = 1000,
+		.noconnect = true,
+	};
+	struct network_helper_opts tx_ops = {
+		.timeout_ms = 1000,
+		.type = SOCK_RAW,
+		.proto = IPPROTO_RAW,
+		.noconnect = true,
+	};
+	struct sockaddr_storage caddr;
+	struct ip_check_defrag *skel;
+	struct nstoken *nstoken;
+	int client_tx_fd = -1;
+	int client_rx_fd = -1;
+	socklen_t caddr_len;
+	int srv_fd = -1;
+	char buf[1024];
+	int len, err;
+
+	skel = ip_check_defrag__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "skel_open"))
+		return;
+
+	if (!ASSERT_OK(setup_topology(ipv6), "setup_topology"))
+		goto out;
+
+	if (!ASSERT_OK(attach(skel, ipv6), "attach"))
+		goto out;
+
+	/* Start server in ns1 */
+	nstoken = open_netns(NS1);
+	if (!ASSERT_OK_PTR(nstoken, "setns ns1"))
+		goto out;
+	srv_fd = start_server(ipv6 ? AF_INET6 : AF_INET, SOCK_DGRAM, NULL, SERVER_PORT, 0);
+	close_netns(nstoken);
+	if (!ASSERT_GE(srv_fd, 0, "start_server"))
+		goto out;
+
+	/* Open tx raw socket in ns0 */
+	nstoken = open_netns(NS0);
+	if (!ASSERT_OK_PTR(nstoken, "setns ns0"))
+		goto out;
+	client_tx_fd = connect_to_fd_opts(srv_fd, &tx_ops);
+	close_netns(nstoken);
+	if (!ASSERT_GE(client_tx_fd, 0, "connect_to_fd_opts"))
+		goto out;
+
+	/* Open rx socket in ns0 */
+	nstoken = open_netns(NS0);
+	if (!ASSERT_OK_PTR(nstoken, "setns ns0"))
+		goto out;
+	client_rx_fd = connect_to_fd_opts(srv_fd, &rx_opts);
+	close_netns(nstoken);
+	if (!ASSERT_GE(client_rx_fd, 0, "connect_to_fd_opts"))
+		goto out;
+
+	/* Bind rx socket to a premeditated port */
+	memset(&caddr, 0, sizeof(caddr));
+	nstoken = open_netns(NS0);
+	if (!ASSERT_OK_PTR(nstoken, "setns ns0"))
+		goto out;
+	if (ipv6) {
+		struct sockaddr_in6 *c = (struct sockaddr_in6 *)&caddr;
+
+		c->sin6_family = AF_INET6;
+		inet_pton(AF_INET6, VETH0_ADDR6, &c->sin6_addr);
+		c->sin6_port = htons(CLIENT_PORT);
+		err = bind(client_rx_fd, (struct sockaddr *)c, sizeof(*c));
+	} else {
+		struct sockaddr_in *c = (struct sockaddr_in *)&caddr;
+
+		c->sin_family = AF_INET;
+		inet_pton(AF_INET, VETH0_ADDR, &c->sin_addr);
+		c->sin_port = htons(CLIENT_PORT);
+		err = bind(client_rx_fd, (struct sockaddr *)c, sizeof(*c));
+	}
+	close_netns(nstoken);
+	if (!ASSERT_OK(err, "bind"))
+		goto out;
+
+	/* Send message in fragments */
+	if (ipv6) {
+		if (!ASSERT_OK(send_frags6(client_tx_fd), "send_frags6"))
+			goto out;
+	} else {
+		if (!ASSERT_OK(send_frags(client_tx_fd), "send_frags"))
+			goto out;
+	}
+
+	if (!ASSERT_EQ(skel->bss->shootdowns, 0, "shootdowns"))
+		goto out;
+
+	/* Receive reassembled msg on server and echo back to client */
+	caddr_len = sizeof(caddr);
+	len = recvfrom(srv_fd, buf, sizeof(buf), 0, (struct sockaddr *)&caddr, &caddr_len);
+	if (!ASSERT_GE(len, 0, "server recvfrom"))
+		goto out;
+	len = sendto(srv_fd, buf, len, 0, (struct sockaddr *)&caddr, caddr_len);
+	if (!ASSERT_GE(len, 0, "server sendto"))
+		goto out;
+
+	/* Expect reassembed message to be echoed back */
+	len = recvfrom(client_rx_fd, buf, sizeof(buf), 0, NULL, NULL);
+	if (!ASSERT_EQ(len, sizeof(MAGIC_MESSAGE) - 1, "client short read"))
+		goto out;
+
+out:
+	if (client_rx_fd != -1)
+		close(client_rx_fd);
+	if (client_tx_fd != -1)
+		close(client_tx_fd);
+	if (srv_fd != -1)
+		close(srv_fd);
+	cleanup_topology();
+	ip_check_defrag__destroy(skel);
+}
+
+void test_bpf_ip_check_defrag(void)
+{
+	if (test__start_subtest("v4"))
+		test_bpf_ip_check_defrag_ok(false);
+	if (test__start_subtest("v6"))
+		test_bpf_ip_check_defrag_ok(true);
+}