selftests/bpf: Add BPF_FIB_LOOKUP_SRC tests

This patch extends the existing fib_lookup test suite by adding two test
cases (for each IP family):

* Test source IP selection from the egressing netdev.
* Test source IP selection when an IP route has a preferred src IP addr.

Signed-off-by: Martynas Pumputis <m@lambda.lt>
Link: https://lore.kernel.org/r/20231007081415.33502-3-m@lambda.lt
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

diff --git a/tools/testing/selftests/bpf/prog_tests/fib_lookup.c b/tools/testing/selftests/bpf/prog_tests/fib_lookup.c
index 2fd05649bad19980d6936353540f04585cbd4fcc..4ad4cd69152eda7cf556def1cc2e0dafdcf3008b 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/fib_lookup.c
+++ b/tools/testing/selftests/bpf/prog_tests/fib_lookup.c
@@ -11,9 +11,13 @@
 
 #define NS_TEST                        "fib_lookup_ns"
 #define IPV6_IFACE_ADDR                "face::face"
+#define IPV6_IFACE_ADDR_SEC    "cafe::cafe"
+#define IPV6_ADDR_DST          "face::3"
 #define IPV6_NUD_FAILED_ADDR   "face::1"
 #define IPV6_NUD_STALE_ADDR    "face::2"
 #define IPV4_IFACE_ADDR                "10.0.0.254"
+#define IPV4_IFACE_ADDR_SEC    "10.1.0.254"
+#define IPV4_ADDR_DST          "10.2.0.254"
 #define IPV4_NUD_FAILED_ADDR   "10.0.0.1"
 #define IPV4_NUD_STALE_ADDR    "10.0.0.2"
 #define IPV4_TBID_ADDR         "172.0.0.254"
@@ -31,6 +35,7 @@ struct fib_lookup_test {
        const char *desc;
        const char *daddr;
        int expected_ret;
+       const char *expected_src;
        int lookup_flags;
        __u32 tbid;
        __u8 dmac[6];
@@ -69,6 +74,22 @@ static const struct fib_lookup_test tests[] = {
          .daddr = IPV6_TBID_DST, .expected_ret = BPF_FIB_LKUP_RET_SUCCESS,
          .lookup_flags = BPF_FIB_LOOKUP_DIRECT | BPF_FIB_LOOKUP_TBID, .tbid = 100,
          .dmac = DMAC_INIT2, },
+       { .desc = "IPv4 set src addr from netdev",
+         .daddr = IPV4_NUD_FAILED_ADDR, .expected_ret = BPF_FIB_LKUP_RET_SUCCESS,
+         .expected_src = IPV4_IFACE_ADDR,
+         .lookup_flags = BPF_FIB_LOOKUP_SRC | BPF_FIB_LOOKUP_SKIP_NEIGH, },
+       { .desc = "IPv6 set src addr from netdev",
+         .daddr = IPV6_NUD_FAILED_ADDR, .expected_ret = BPF_FIB_LKUP_RET_SUCCESS,
+         .expected_src = IPV6_IFACE_ADDR,
+         .lookup_flags = BPF_FIB_LOOKUP_SRC | BPF_FIB_LOOKUP_SKIP_NEIGH, },
+       { .desc = "IPv4 set prefsrc addr from route",
+         .daddr = IPV4_ADDR_DST, .expected_ret = BPF_FIB_LKUP_RET_SUCCESS,
+         .expected_src = IPV4_IFACE_ADDR_SEC,
+         .lookup_flags = BPF_FIB_LOOKUP_SRC | BPF_FIB_LOOKUP_SKIP_NEIGH, },
+       { .desc = "IPv6 set prefsrc addr route",
+         .daddr = IPV6_ADDR_DST, .expected_ret = BPF_FIB_LKUP_RET_SUCCESS,
+         .expected_src = IPV6_IFACE_ADDR_SEC,
+         .lookup_flags = BPF_FIB_LOOKUP_SRC | BPF_FIB_LOOKUP_SKIP_NEIGH, },
 };
 
 static int ifindex;
@@ -97,6 +118,13 @@ static int setup_netns(void)
        SYS(fail, "ip neigh add %s dev veth1 nud failed", IPV4_NUD_FAILED_ADDR);
        SYS(fail, "ip neigh add %s dev veth1 lladdr %s nud stale", IPV4_NUD_STALE_ADDR, DMAC);
 
+       /* Setup for prefsrc IP addr selection */
+       SYS(fail, "ip addr add %s/24 dev veth1", IPV4_IFACE_ADDR_SEC);
+       SYS(fail, "ip route add %s/32 dev veth1 src %s", IPV4_ADDR_DST, IPV4_IFACE_ADDR_SEC);
+
+       SYS(fail, "ip addr add %s/64 dev veth1 nodad", IPV6_IFACE_ADDR_SEC);
+       SYS(fail, "ip route add %s/128 dev veth1 src %s", IPV6_ADDR_DST, IPV6_IFACE_ADDR_SEC);
+
        /* Setup for tbid lookup tests */
        SYS(fail, "ip addr add %s/24 dev veth2", IPV4_TBID_ADDR);
        SYS(fail, "ip route del %s/24 dev veth2", IPV4_TBID_NET);
@@ -133,9 +161,12 @@ static int set_lookup_params(struct bpf_fib_lookup *params, const struct fib_loo
 
        if (inet_pton(AF_INET6, test->daddr, params->ipv6_dst) == 1) {
                params->family = AF_INET6;
-               ret = inet_pton(AF_INET6, IPV6_IFACE_ADDR, params->ipv6_src);
-               if (!ASSERT_EQ(ret, 1, "inet_pton(IPV6_IFACE_ADDR)"))
-                       return -1;
+               if (!(test->lookup_flags & BPF_FIB_LOOKUP_SRC)) {
+                       ret = inet_pton(AF_INET6, IPV6_IFACE_ADDR, params->ipv6_src);
+                       if (!ASSERT_EQ(ret, 1, "inet_pton(IPV6_IFACE_ADDR)"))
+                               return -1;
+               }
+
                return 0;
        }
 
@@ -143,9 +174,12 @@ static int set_lookup_params(struct bpf_fib_lookup *params, const struct fib_loo
        if (!ASSERT_EQ(ret, 1, "convert IP[46] address"))
                return -1;
        params->family = AF_INET;
-       ret = inet_pton(AF_INET, IPV4_IFACE_ADDR, &params->ipv4_src);
-       if (!ASSERT_EQ(ret, 1, "inet_pton(IPV4_IFACE_ADDR)"))
-               return -1;
+
+       if (!(test->lookup_flags & BPF_FIB_LOOKUP_SRC)) {
+               ret = inet_pton(AF_INET, IPV4_IFACE_ADDR, &params->ipv4_src);
+               if (!ASSERT_EQ(ret, 1, "inet_pton(IPV4_IFACE_ADDR)"))
+                       return -1;
+       }
 
        return 0;
 }
@@ -156,6 +190,40 @@ static void mac_str(char *b, const __u8 *mac)
                mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
 }
 
+static void assert_src_ip(struct bpf_fib_lookup *fib_params, const char *expected_src)
+{
+       int ret;
+       __u32 src6[4];
+       __be32 src4;
+
+       switch (fib_params->family) {
+       case AF_INET6:
+               ret = inet_pton(AF_INET6, expected_src, src6);
+               ASSERT_EQ(ret, 1, "inet_pton(expected_src)");
+
+               ret = memcmp(src6, fib_params->ipv6_src, sizeof(fib_params->ipv6_src));
+               if (!ASSERT_EQ(ret, 0, "fib_lookup ipv6 src")) {
+                       char str_src6[64];
+
+                       inet_ntop(AF_INET6, fib_params->ipv6_src, str_src6,
+                                 sizeof(str_src6));
+                       printf("ipv6 expected %s actual %s ", expected_src,
+                              str_src6);
+               }
+
+               break;
+       case AF_INET:
+               ret = inet_pton(AF_INET, expected_src, &src4);
+               ASSERT_EQ(ret, 1, "inet_pton(expected_src)");
+
+               ASSERT_EQ(fib_params->ipv4_src, src4, "fib_lookup ipv4 src");
+
+               break;
+       default:
+               PRINT_FAIL("invalid addr family: %d", fib_params->family);
+       }
+}
+
 void test_fib_lookup(void)
 {
        struct bpf_fib_lookup *fib_params;
@@ -207,6 +275,9 @@ void test_fib_lookup(void)
                ASSERT_EQ(skel->bss->fib_lookup_ret, tests[i].expected_ret,
                          "fib_lookup_ret");
 
+               if (tests[i].expected_src)
+                       assert_src_ip(fib_params, tests[i].expected_src);
+
                ret = memcmp(tests[i].dmac, fib_params->dmac, sizeof(tests[i].dmac));
                if (!ASSERT_EQ(ret, 0, "dmac not match")) {
                        char expected[18], actual[18];