tc_l2_announcement.c
// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
/* Copyright Authors of Cilium */
#include "common.h"
/* Enable debug output */
#define DEBUG
/* Set NODE_MAC equal to mac_two */
#define NODE_MAC { .addr = {0x13, 0x37, 0x13, 0x37, 0x13, 0x37} }
#define SECCTX_FROM_IPCACHE 1
/* Set the LXC source address to be the address of pod one */
#define LXC_IPV4 (__be32)v4_pod_one
#include "config_replacement.h"
/* Enable CT debug output */
#undef QUIET_CT
#include <bpf/ctx/skb.h>
#include "pktgen.h"
/* Set ETH_HLEN to 14 to indicate that the packet has a 14 byte ethernet header */
#define ETH_HLEN 14
/* Enable code paths under test */
#define ENABLE_IPV4
#define ENABLE_L2_ANNOUNCEMENTS
#include <bpf_host.c>
struct {
__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
__uint(key_size, sizeof(__u32));
__uint(max_entries, 2);
__array(values, int());
} entry_call_map __section(".maps") = {
.values = {
[0] = &cil_from_netdev,
},
};
/* Setup for this test:
* +-------------------------+ +--------------------------------------+ +--------------------------+
* |L2:mac_one, L3:v4_ext_one|---| ARP Request broadcast for v4_svc_one |--->|L2:mac_two, L3:v4_node_one|
* +-------------------------+ +--------------------------------------+ +--------------------------+
* ^ +-------------------------------------------------------------------+ |
* \---|ARP Reply, SHR:mac_two, SIP:v4_svc_one, DHR:mac_one, DIP:v4_ext_one|---/
* +-------------------------------------------------------------------+
*/
static volatile const __u8 mac_bcast[] = {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF};
static __always_inline int build_packet(struct __ctx_buff *ctx)
{
struct pktgen builder;
volatile const __u8 *src = mac_one;
volatile const __u8 *dst = mac_bcast;
struct ethhdr *l2;
struct arphdreth *l3;
/* Init packet builder */
pktgen__init(&builder, ctx);
/* Push ethernet header */
l2 = pktgen__push_ethhdr(&builder);
if (!l2)
return TEST_ERROR;
ethhdr__set_macs(l2, (__u8 *)src, (__u8 *)dst);
/* Push ARP header */
l3 = pktgen__push_arphdr_ethernet(&builder);
if (!l3)
return TEST_ERROR;
l3->ar_op = bpf_htons(ARPOP_REQUEST);
memcpy(l3->ar_sha, (__u8 *)mac_one, ETH_ALEN);
l3->ar_sip = v4_ext_one;
memcpy(l3->ar_tha, (__u8 *)mac_bcast, ETH_ALEN);
l3->ar_tip = v4_svc_one;
/* Calc lengths, set protocol fields and calc checksums */
pktgen__finish(&builder);
return 0;
}
PKTGEN("tc", "0_no_entry")
int l2_announcement_arp_no_entry_pktgen(struct __ctx_buff *ctx)
{
return build_packet(ctx);
}
/* Test that sending a ARP broadcast request without entries in the map.
*/
SETUP("tc", "0_no_entry")
int l2_announcement_arp_no_entry_setup(struct __ctx_buff *ctx)
{
/* Jump into the entrypoint */
tail_call_static(ctx, &entry_call_map, 0);
/* Fail if we didn't jump */
return TEST_ERROR;
}
CHECK("tc", "0_no_entry")
int l2_announcement_arp_no_entry_check(__maybe_unused const struct __ctx_buff *ctx)
{
void *data;
void *data_end;
__u32 *status_code;
struct ethhdr *l2;
struct arphdreth *l3;
test_init();
data = ctx_data(ctx);
data_end = ctx_data_end(ctx);
if (data + sizeof(__u32) > data_end)
test_fatal("status code out of bounds");
status_code = data;
/* The program should pass unknown ARP messages to the stack */
assert(*status_code == TC_ACT_OK);
l2 = data + sizeof(__u32);
if ((void *)l2 + sizeof(struct ethhdr) > data_end)
test_fatal("l2 out of bounds");
l3 = data + sizeof(__u32) + sizeof(struct ethhdr);
if ((void *)l3 + sizeof(struct arphdreth) > data_end)
test_fatal("l3 out of bounds");
assert(memcmp(l2->h_source, (__u8 *)mac_one, ETH_HLEN) != 0);
assert(memcmp(l2->h_dest, (__u8 *)mac_bcast, ETH_HLEN) != 0);
assert(l3->ar_op == bpf_htons(ARPOP_REQUEST));
assert(l3->ar_sip == v4_ext_one);
assert(l3->ar_tip == v4_svc_one);
assert(memcmp(l3->ar_sha, (__u8 *)mac_one, ETH_HLEN) != 0);
assert(memcmp(l3->ar_tha, (__u8 *)mac_bcast, ETH_HLEN) != 0);
test_finish();
}
PKTGEN("tc", "1_happy_path")
int l2_announcement_arp_happy_path_pktgen(struct __ctx_buff *ctx)
{
return build_packet(ctx);
}
/* Test that sending a ARP broadcast request matching an entry in the
* L2_RESPONDER_MAP4 results in a valid ARP reply.
*/
SETUP("tc", "1_happy_path")
int l2_announcement_arp_happy_path_setup(struct __ctx_buff *ctx)
{
struct l2_responder_v4_key key;
struct l2_responder_v4_stats value = {0};
__u32 index;
__u64 time;
key.ifindex = 0;
key.ip4 = v4_svc_one;
map_update_elem(&L2_RESPONDER_MAP4, &key, &value, BPF_ANY);
index = RUNTIME_CONFIG_AGENT_LIVENESS;
time = ktime_get_ns();
map_update_elem(&CONFIG_MAP, &index, &time, BPF_ANY);
/* Jump into the entrypoint */
tail_call_static(ctx, &entry_call_map, 0);
/* Fail if we didn't jump */
return TEST_ERROR;
}
CHECK("tc", "1_happy_path")
int l2_announcement_arp_happy_path_check(__maybe_unused const struct __ctx_buff *ctx)
{
void *data;
void *data_end;
__u32 *status_code;
struct ethhdr *l2;
struct arphdreth *l3;
test_init();
data = (void *)(long)ctx->data;
data_end = (void *)(long)ctx->data_end;
if (data + sizeof(__u32) > data_end)
test_fatal("status code out of bounds");
status_code = data;
assert(*status_code == TC_ACT_REDIRECT);
l2 = data + sizeof(__u32);
if ((void *)l2 + sizeof(struct ethhdr) > data_end)
test_fatal("l2 out of bounds");
l3 = data + sizeof(__u32) + sizeof(struct ethhdr);
if ((void *)l3 + sizeof(struct arphdreth) > data_end)
test_fatal("l3 out of bounds");
assert(memcmp(l2->h_source, (__u8 *)mac_two, ETH_HLEN) != 0);
assert(memcmp(l2->h_dest, (__u8 *)mac_one, ETH_HLEN) != 0);
assert(l3->ar_op == bpf_htons(ARPOP_REPLY));
assert(l3->ar_sip == v4_svc_one);
assert(l3->ar_tip == v4_ext_one);
assert(memcmp(l3->ar_sha, (__u8 *)mac_two, ETH_HLEN) != 0);
assert(memcmp(l3->ar_tha, (__u8 *)mac_one, ETH_HLEN) != 0);
test_finish();
}