bpf/tests: Add IPv6 NDP bpf test

This commit adds bpf/tests/ipv6_ndp_from_netdev_test.c to cover two
scenarios:
1. from_netdev receives IPv6 NS for a pod IP on the same host
2. from_netdev receives IPv6 NS for the node IP (eth0's addr)

For case 1, from_netdev should return a NA on behalf of the target pod
to avoid cilium#30926.
for case 2, it must return the NS to stack to address cilium#14509.

Signed-off-by: Zhichuan Liang <gray.liang@isovalent.com>

bpf/tests/ipv6_ndp_from_netdev_test.c

@@ -0,0 +1,259 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+/* Copyright Authors of Cilium */
+
+#include "common.h"
+#include <bpf/ctx/skb.h>
+#include "pktgen.h"
+#define ROUTER_IP
+#define HOST_IP
+#include "config_replacement.h"
+#undef ROUTER_IP
+#undef HOST_IP
+
+#define ENABLE_IPV4
+#define ENABLE_IPV6
+#define SECCTX_FROM_IPCACHE 1
+
+#include "bpf_host.c"
+
+#include "lib/ipcache.h"
+#include "lib/endpoint.h"
+
+#define FROM_NETDEV 0
+
+struct {
+	__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
+	__uint(key_size, sizeof(__u32));
+	__uint(max_entries, 1);
+	__array(values, int());
+} entry_call_map __section(".maps") = {
+	.values = {
+		[FROM_NETDEV] = &cil_from_netdev,
+	},
+};
+
+PKTGEN("tc", "01_ipv6_from_netdev_ns_for_pod")
+int ipv6_from_netdev_ns_for_pod_pktgen(struct __ctx_buff *ctx)
+{
+	struct pktgen builder;
+	struct icmp6hdr *l4;
+	void *data;
+
+	pktgen__init(&builder, ctx);
+
+	l4 = pktgen__push_ipv6_icmp6_packet(&builder,
+					    (__u8 *)mac_one, (__u8 *)mac_two,
+					    (__u8 *)v6_pod_one, (__u8 *)v6_pod_two,
+					    ICMP6_NS_MSG_TYPE);
+	if (!l4)
+		return TEST_ERROR;
+
+	data = pktgen__push_data(&builder, (__u8 *)v6_pod_three, 16);
+	if (!data)
+		return TEST_ERROR;
+
+	__u8 options[] = {0x1, 0x1, 0x1, 0x1, 0x1, 0x1, 0x1, 0x1};
+
+	data = pktgen__push_data(&builder, (__u8 *)options, 8);
+
+	pktgen__finish(&builder);
+	return 0;
+}
+
+SETUP("tc", "01_ipv6_from_netdev_ns_for_pod")
+int ipv6_from_netdev_ns_for_pod_setup(struct __ctx_buff *ctx)
+{
+	endpoint_v6_add_entry((union v6addr *)v6_pod_three, 0, 0, 0,
+			      (__u8 *)mac_three, (__u8 *)mac_two);
+	tail_call_static(ctx, entry_call_map, FROM_NETDEV);
+	return TEST_ERROR;
+}
+
+CHECK("tc", "01_ipv6_from_netdev_ns_for_pod")
+int ipv6_from_netdev_ns_for_pod_check(const struct __ctx_buff *ctx)
+{
+	void *data;
+	void *data_end;
+	__u32 *status_code;
+	struct ethhdr *l2;
+	struct ipv6hdr *l3;
+	struct icmp6hdr *l4;
+	void *payload;
+
+	test_init();
+
+	data = (void *)(long)ctx->data;
+	data_end = (void *)(long)ctx->data_end;
+
+	if (data + sizeof(*status_code) > data_end)
+		test_fatal("status code out of bounds");
+
+	status_code = data;
+	printk("status_code: %d\n", *status_code);
+	assert(*status_code == CTX_ACT_REDIRECT);
+
+	l2 = data + sizeof(*status_code);
+
+	if ((void *)l2 + sizeof(struct ethhdr) > data_end)
+		test_fatal("l2 out of bounds");
+
+	if (l2->h_proto != bpf_htons(ETH_P_IPV6))
+		test_fatal("l2 proto hasn't been set to ETH_P_IP");
+
+	union macaddr node_mac = NODE_MAC;
+
+	if (memcmp(l2->h_source, (__u8 *)&node_mac.addr, ETH_ALEN) != 0)
+		test_fatal("src mac hasn't been set to node mac");
+
+	if (memcmp(l2->h_dest, (__u8 *)mac_one, ETH_ALEN) != 0)
+		test_fatal("dest mac hasn't been set to source mac");
+
+	l3 = (void *)l2 + sizeof(struct ethhdr);
+
+	if ((void *)l3 + sizeof(struct ipv6hdr) > data_end)
+		test_fatal("l3 out of bounds");
+
+	union v6addr router_ip;
+
+	BPF_V6(router_ip, ROUTER_IP);
+	if (memcmp((__u8 *)&l3->saddr, (__u8 *)&router_ip, 16) != 0)
+		test_fatal("src IP hasn't been set to router IP");
+
+	if (memcmp((__u8 *)&l3->daddr, (__u8 *)v6_pod_one, 16) != 0)
+		test_fatal("dest IP hasn't been set to source IP");
+
+	l4 = (void *)l3 + sizeof(struct ipv6hdr);
+
+	if ((void *)l4 + sizeof(struct icmp6hdr) > data_end)
+		test_fatal("l4 out of bounds");
+
+	if (l4->icmp6_type != ICMP6_NA_MSG_TYPE)
+		test_fatal("icmp6 type hasn't been set to ICMP6_NA_MSG_TYPE");
+
+	payload = (void *)l4 + sizeof(struct icmp6hdr);
+	if ((void *)payload + 24 > data_end)
+		test_fatal("payload out of bounds");
+
+	void *target = payload;
+
+	if (memcmp(target, (__u8 *)v6_pod_three, 16) != 0)
+		test_fatal("icmp6 payload target hasn't been set properly");
+
+	void *target_lladdr = payload + 16 + 2;
+
+	if (memcmp(target_lladdr, (__u8 *)&node_mac.addr, ETH_ALEN) != 0)
+		test_fatal("icmp6 payload target_lladdr hasn't been set properly");
+
+	test_finish();
+}
+
+PKTGEN("tc", "02_ipv6_from_netdev_ns_for_node_ip")
+int ipv6_from_netdev_ns_for_node_ip_pktgen(struct __ctx_buff *ctx)
+{
+	struct pktgen builder;
+	struct icmp6hdr *l4;
+	void *data;
+
+	pktgen__init(&builder, ctx);
+
+	l4 = pktgen__push_ipv6_icmp6_packet(&builder,
+					    (__u8 *)mac_one, (__u8 *)mac_two,
+					    (__u8 *)v6_pod_one, (__u8 *)v6_pod_two,
+					    ICMP6_NS_MSG_TYPE);
+	if (!l4)
+		return TEST_ERROR;
+
+	union v6addr node_ip;
+
+	BPF_V6(node_ip, HOST_IP);
+	data = pktgen__push_data(&builder, (__u8 *)&node_ip, 16);
+	if (!data)
+		return TEST_ERROR;
+
+	__u8 options[] = {0x1, 0x1, 0x1, 0x1, 0x1, 0x1, 0x1, 0x1};
+
+	data = pktgen__push_data(&builder, (__u8 *)options, 8);
+
+	pktgen__finish(&builder);
+	return 0;
+}
+
+SETUP("tc", "02_ipv6_from_netdev_ns_for_node_ip")
+int ipv6_from_netdev_ns_for_node_ip_setup(struct __ctx_buff *ctx)
+{
+	union v6addr node_ip;
+
+	BPF_V6(node_ip, HOST_IP);
+	endpoint_v6_add_entry((union v6addr *)&node_ip, 0, 0, ENDPOINT_F_HOST,
+			      (__u8 *)mac_three, (__u8 *)mac_two);
+	tail_call_static(ctx, entry_call_map, FROM_NETDEV);
+	return TEST_ERROR;
+}
+
+CHECK("tc", "02_ipv6_from_netdev_ns_for_node_ip")
+int ipv6_from_netdev_ns_for_node_ip_check(const struct __ctx_buff *ctx)
+{
+	void *data;
+	void *data_end;
+	__u32 *status_code;
+	struct ethhdr *l2;
+	struct ipv6hdr *l3;
+	struct icmp6hdr *l4;
+	void *payload;
+
+	test_init();
+
+	data = (void *)(long)ctx->data;
+	data_end = (void *)(long)ctx->data_end;
+
+	if (data + sizeof(*status_code) > data_end)
+		test_fatal("status code out of bounds");
+
+	status_code = data;
+	printk("status_code: %d\n", *status_code);
+	assert(*status_code == CTX_ACT_OK);
+
+	l2 = data + sizeof(*status_code);
+	if ((void *)l2 + sizeof(struct ethhdr) > data_end)
+		test_fatal("l2 out of bounds");
+
+	if (l2->h_proto != bpf_htons(ETH_P_IPV6))
+		test_fatal("l2 proto hasn't been set to ETH_P_IP");
+
+	if (memcmp(l2->h_source, (__u8 *)mac_one, ETH_ALEN) != 0)
+		test_fatal("src mac hasn't been set to source ep's mac");
+
+	if (memcmp(l2->h_dest, (__u8 *)mac_two, ETH_ALEN) != 0)
+		test_fatal("dest mac hasn't been set to dest ep's mac");
+
+	l3 = (void *)l2 + sizeof(struct ethhdr);
+
+	if ((void *)l3 + sizeof(struct ipv6hdr) > data_end)
+		test_fatal("l3 out of bounds");
+
+	if (memcmp((__u8 *)&l3->saddr, (__u8 *)v6_pod_one, 16) != 0)
+		test_fatal("src IP was changed");
+
+	if (memcmp((__u8 *)&l3->daddr, (__u8 *)v6_pod_two, 16) != 0)
+		test_fatal("dest IP was changed");
+
+	l4 = (void *)l3 + sizeof(struct ipv6hdr);
+
+	if ((void *)l4 + sizeof(struct icmp6hdr) > data_end)
+		test_fatal("l4 out of bounds");
+
+	if (l4->icmp6_type != ICMP6_NS_MSG_TYPE)
+		test_fatal("icmp6 type was changed");
+
+	payload = (void *)l4 + sizeof(struct icmp6hdr);
+	if ((void *)payload + 24 > data_end)
+		test_fatal("payload out of bounds");
+
+	union v6addr node_ip;
+
+	BPF_V6(node_ip, HOST_IP);
+	if (memcmp(payload, (__u8 *)&node_ip, 16) != 0)
+		test_fatal("icmp6 payload target was changed");
+
+	test_finish();
+}

bpf/tests/pktgen.h

@@ -19,6 +19,7 @@
 #include <linux/if_ether.h>
 #include <linux/tcp.h>
 #include <linux/udp.h>
+#include <linux/icmpv6.h>
 
 /* A collection of pre-defined Ethernet MAC addresses, so tests can reuse them
  * without having to come up with custom addresses.
@@ -418,6 +419,13 @@ struct tcphdr *pktgen__push_default_tcphdr(struct pktgen *builder)
 	return hdr;
 }
 
+static __always_inline
+__attribute__((warn_unused_result))
+struct icmp6hdr *pktgen__push_icmp6hdr(struct pktgen *builder)
+{
+	return pktgen__push_rawhdr(builder, sizeof(struct icmp6hdr), PKT_LAYER_ICMPV6);
+}
+
 /* Push an empty ESP header onto the packet */
 static __always_inline
 __attribute__((warn_unused_result))
@@ -688,6 +696,39 @@ pktgen__push_ipv6_tcp_packet(struct pktgen *builder,
 	return l4;
 }
 
+static __always_inline struct icmp6hdr *
+pktgen__push_ipv6_icmp6_packet(struct pktgen *builder,
+			       __u8 *smac, __u8 *dmac,
+			       __u8 *saddr, __u8 *daddr,
+			       __u8 icmp6_type)
+{
+	struct ethhdr *l2;
+	struct ipv6hdr *l3;
+	struct icmp6hdr *l4;
+
+	l2 = pktgen__push_ethhdr(builder);
+	if (!l2)
+		return NULL;
+
+	ethhdr__set_macs(l2, smac, dmac);
+
+	l3 = pktgen__push_default_ipv6hdr(builder);
+	if (!l3)
+		return NULL;
+
+	ipv6hdr__set_addrs(l3, saddr, daddr);
+
+	l4 = pktgen__push_icmp6hdr(builder);
+	if (!l4)
+		return NULL;
+
+	l4->icmp6_type = icmp6_type;
+	l4->icmp6_code = 0;
+	l4->icmp6_cksum = 0;
+
+	return l4;
+}
+
 static __always_inline void pktgen__finish_eth(const struct pktgen *builder, int i)
 {
 	struct ethhdr *eth_layer;