bpf netd: Add local_net_access bpf map along with lookup method.
local_net_access is of type BPF_MAP_TYPE_LPM_TRIE (longest prefix
matching map) which stores interface index, remote address, protocol
and remote port. Lookup method is_local_net_access_allowed() returns
false if the arguments are found in the map and disallowed, otherwise
it returns true.
Test: Locally tested by adding values from userspace and querying the
bpf map.
Bug: 373608779
Change-Id: Ia34b3cb5613b56f6db5b224ec03f8c9909a49fe1
diff --git a/bpf/progs/netd.c b/bpf/progs/netd.c
index 8897627..41ea82d 100644
--- a/bpf/progs/netd.c
+++ b/bpf/progs/netd.c
@@ -99,6 +99,11 @@
DEFINE_BPF_MAP_RO_NETD(data_saver_enabled_map, ARRAY, uint32_t, bool,
DATA_SAVER_ENABLED_MAP_SIZE)
+DEFINE_BPF_MAP_EXT(local_net_access_map, LPM_TRIE, LocalNetAccessKey, bool, 1000,
+ AID_ROOT, AID_NET_BW_ACCT, 0060, "fs_bpf_net_shared", "", PRIVATE,
+ BPFLOADER_MAINLINE_25Q2_VERSION, BPFLOADER_MAX_VER, LOAD_ON_ENG, LOAD_ON_USER,
+ LOAD_ON_USERDEBUG, 0)
+
// iptables xt_bpf programs need to be usable by both netd and netutils_wrappers
// selinux contexts, because even non-xt_bpf iptables mutations are implemented as
// a full table dump, followed by an update in userspace, and then a reload into the kernel,
@@ -230,6 +235,23 @@
: bpf_skb_load_bytes(skb, L3_off, to, len);
}
+/*
+ * False iff arguments are found with longest prefix match lookup and disallowed.
+ */
+static inline __always_inline __unused bool is_local_net_access_allowed(const uint32_t if_index,
+ const struct in6_addr* remote_ip6, const uint16_t protocol, const __be16 remote_port) {
+ LocalNetAccessKey query_key = {
+ .lpm_bitlen = 8 * (sizeof(if_index) + sizeof(*remote_ip6) + sizeof(protocol)
+ + sizeof(remote_port)),
+ .if_index = if_index,
+ .remote_ip6 = *remote_ip6,
+ .protocol = protocol,
+ .remote_port = remote_port
+ };
+ bool* v = bpf_local_net_access_map_lookup_elem(&query_key);
+ return v ? *v : true;
+}
+
static __always_inline inline void do_packet_tracing(
const struct __sk_buff* const skb, const struct egress_bool egress, const uint32_t uid,
const uint32_t tag, const struct kver_uint kver) {
diff --git a/bpf/progs/netd.h b/bpf/progs/netd.h
index be7c311..6561311 100644
--- a/bpf/progs/netd.h
+++ b/bpf/progs/netd.h
@@ -185,6 +185,7 @@
#define PACKET_TRACE_RINGBUF_PATH BPF_NETD_PATH "map_netd_packet_trace_ringbuf"
#define PACKET_TRACE_ENABLED_MAP_PATH BPF_NETD_PATH "map_netd_packet_trace_enabled_map"
#define DATA_SAVER_ENABLED_MAP_PATH BPF_NETD_PATH "map_netd_data_saver_enabled_map"
+#define LOCAL_NET_ACCESS_MAP_PATH BPF_NETD_PATH "map_netd_local_net_access_map"
#endif // __cplusplus
@@ -245,6 +246,18 @@
} IngressDiscardValue;
STRUCT_SIZE(IngressDiscardValue, 2 * 4); // 8
+typedef struct {
+ // Longest prefix match length in bits (value from 0 to 192).
+ uint32_t lpm_bitlen;
+ uint32_t if_index;
+ // IPv4 uses IPv4-mapped IPv6 address format.
+ struct in6_addr remote_ip6;
+ // u16 instead of u8 to avoid padding due to alignment requirement.
+ uint16_t protocol;
+ __be16 remote_port;
+} LocalNetAccessKey;
+STRUCT_SIZE(LocalNetAccessKey, 4 + 4 + 16 + 2 + 2); // 28
+
// Entry in the configuration map that stores which UID rules are enabled.
#define UID_RULES_CONFIGURATION_KEY 0
// Entry in the configuration map that stores which stats map is currently in use.
diff --git a/bpf/tests/mts/bpf_existence_test.cpp b/bpf/tests/mts/bpf_existence_test.cpp
index 0b5b7be..d605379 100644
--- a/bpf/tests/mts/bpf_existence_test.cpp
+++ b/bpf/tests/mts/bpf_existence_test.cpp
@@ -20,7 +20,9 @@
#include <set>
#include <string>
+#include <android-base/properties.h>
#include <android-modules-utils/sdk_level.h>
+#include <android/api-level.h>
#include <bpf/BpfUtils.h>
#include <gtest/gtest.h>
@@ -46,6 +48,11 @@
class BpfExistenceTest : public ::testing::Test {
};
+//ToDo: replace isAtLeast25Q2 with IsAtLeastB once sdk_level have been upgraded to 36 on aosp/main
+const bool unreleased = (android::base::GetProperty("ro.build.version.codename", "REL") != "REL");
+const int api_level = unreleased ? __ANDROID_API_FUTURE__ : android_get_device_api_level();
+const bool isAtLeast25Q2 = (api_level > __ANDROID_API_V__);
+
// Part of Android R platform (for 4.9+), but mainlined in S
static const set<string> PLATFORM_ONLY_IN_R = {
PLATFORM "map_offload_tether_ingress_map",
@@ -159,6 +166,11 @@
NETD "prog_netd_setsockopt_prog",
};
+// Provided by *current* mainline module for 25Q2+ devices
+static const set<string> MAINLINE_FOR_25Q2_PLUS = {
+ NETD "map_netd_local_net_access_map",
+};
+
static void addAll(set<string>& a, const set<string>& b) {
a.insert(b.begin(), b.end());
}
@@ -209,6 +221,9 @@
DO_EXPECT(IsAtLeastV(), MAINLINE_FOR_V_PLUS);
DO_EXPECT(IsAtLeastV() && isAtLeastKernelVersion(5, 4, 0), MAINLINE_FOR_V_5_4_PLUS);
+ if (isAtLeast25Q2) ASSERT_TRUE(isAtLeastKernelVersion(5, 4, 0));
+ DO_EXPECT(isAtLeast25Q2, MAINLINE_FOR_25Q2_PLUS);
+
for (const auto& file : mustExist) {
EXPECT_EQ(0, access(file.c_str(), R_OK)) << file << " does not exist";
}