Use bpftool instead of iproute2 to load eBPF and XDP maps.

fruffy · fruffy · commit eb1ef3d22148 · 2024-12-22T20:58:25.000+01:00
Signed-off-by: fruffy &lt;fruffy@nyu.edu&gt;
diff --git a/backends/ebpf/CMakeLists.txt b/backends/ebpf/CMakeLists.txt
@@ -21,17 +21,17 @@ if(NOT APPLE)
   set(FETCHCONTENT_QUIET OFF)
   fetchcontent_declare(
     bpfrepo
-    URL https://github.com/libbpf/libbpf/archive/refs/tags/v1.4.1.tar.gz
-    URL_HASH SHA256=cc01a3a05d25e5978c20be7656f14eb8b6fcb120bb1c7e8041e497814fc273cb
-    SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/runtime/contrib/libbpf
+    URL https://github.com/libbpf/bpftool/releases/download/v7.5.0/bpftool-libbpf-v7.5.0-sources.tar.gz
+    # URL_HASH SHA256=cc01a3a05d25e5978c20be7656f14eb8b6fcb120bb1c7e8041e497814fc273cb
+    SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/runtime/contrib/bpftool
     USES_TERMINAL_DOWNLOAD TRUE
     GIT_PROGRESS TRUE
     DOWNLOAD_EXTRACT_TIMESTAMP TRUE
   )
   fetchcontent_makeavailable(bpfrepo)
   set(FETCHCONTENT_QUIET ${FETCHCONTENT_QUIET_PREV})
   # Check if we have already built the libbpf library.
-  find_library(LIBBPF NAMES bpf HINTS "${CMAKE_CURRENT_SOURCE_DIR}/runtime/usr/lib64/")
+  find_library(LIBBPF NAMES bpf HINTS "${CMAKE_CURRENT_SOURCE_DIR}/runtime/install/libbpf/")
   if (NOT LIBBPF)
     message("Building libbpf...")
     execute_process(
diff --git a/backends/ebpf/build_libbpf b/backends/ebpf/build_libbpf
@@ -10,7 +10,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-""" This programs builds a libbpf static library and places it in the runtime
+""" This programs builds a bpftool binary and the libbpf static library and places it in the runtime
     folder. The library and its headers are required by the kernel target.
 """
 
@@ -31,21 +31,24 @@ def main() -> int:
         level=logging.WARN,
         filemode="w",
     )
-    libbpf_dir = FILE_DIR.joinpath("runtime/contrib/libbpf")
-    libbpf_src_dir = libbpf_dir.joinpath("src")
-    libbpf_build_dir = libbpf_src_dir.joinpath("build")
-    libbpf_target_dir = FILE_DIR.joinpath("runtime")
-    # Create the libbpf build directory
-    testutils.check_and_create_dir(libbpf_build_dir)
-    # Build libbpf
-    mk_cmd = f"make -C {libbpf_src_dir} install "
+    bpftool_dir = FILE_DIR.joinpath("runtime/contrib/bpftool")
+    bpftool_src_dir = bpftool_dir.joinpath("src")
+    bpftool_build_dir = bpftool_src_dir.joinpath("build")
+    bpftool_target_dir = FILE_DIR.joinpath("runtime/install/")
+    bpftool_target_dir.mkdir(parents=True, exist_ok=True)
+    # Create the bpftool build directory
+    testutils.check_and_create_dir(bpftool_build_dir)
+    # Build bpftool
+    mk_cmd = f"make -C {bpftool_src_dir} install "
+    mk_cmd += f"OUTPUT={bpftool_target_dir}/ "
     mk_cmd += "BUILD_STATIC_ONLY=y "
-    mk_cmd += f"OBJDIR={libbpf_build_dir} "
-    mk_cmd += f"DESTDIR={libbpf_target_dir} "
+    mk_cmd += f"OBJDIR={bpftool_build_dir} "
+    mk_cmd += f"DESTDIR={bpftool_target_dir} "
     mk_cmd += "EXTRA_CFLAGS=-fPIE"
+    print(mk_cmd)
     result = testutils.exec_process(args=mk_cmd)
     if result.returncode != testutils.SUCCESS:
-        testutils.log.error("Could not build libbpf")
+        testutils.log.error("Could not build bpftool")
     return result.returncode
 
 
diff --git a/backends/ebpf/run-ebpf-test.py b/backends/ebpf/run-ebpf-test.py
@@ -123,9 +123,9 @@ def __init__(self):
         self.replace = False  # Replace previous outputs.
         self.target = "test"  # The name of the target compiler.
         # Actual location of the test framework.
-        self.testdir = str(FILE_DIR)
+        self.testdir = FILE_DIR
         # The location of the eBPF runtime, some targets may overwrite this.
-        self.runtimedir = str(FILE_DIR.joinpath("runtime"))
+        self.runtimedir = FILE_DIR.joinpath("runtime")
         self.extern = ""  # Path to C file with extern definition.
 
 
diff --git a/backends/ebpf/runtime/.gitignore b/backends/ebpf/runtime/.gitignore
@@ -0,0 +1 @@
+install
diff --git a/backends/ebpf/runtime/contrib/.gitignore b/backends/ebpf/runtime/contrib/.gitignore
@@ -1 +1,2 @@
 libbpf
+bpftool
diff --git a/backends/ebpf/runtime/ebpf_kernel.h b/backends/ebpf/runtime/ebpf_kernel.h
@@ -61,92 +61,23 @@ limitations under the License.
 // This file contains the definitions of all the kernel bpf essentials
 #include <bpf/bpf_helpers.h>
 
-/// A helper structure used by an eBPF C program
-/// to describe map attributes for the elf_bpf loader
-/// FIXME: We only need this because we are loading with iproute2
-struct bpf_elf_map {
-    __u32 type;
-    __u32 size_key;
-    __u32 size_value;
-    __u32 max_elem;
-    __u32 flags;
-    __u32 id;
-    __u32 pinning;
-    __u32 inner_id;
-    __u32 inner_idx;
-};
-
 /// Simple descriptor which replaces the kernel sk_buff structure.
 #define SK_BUFF struct __sk_buff
 
-/// From iproute2, annotate table with BTF which allows to read types at runtime.
-#define BPF_ANNOTATE_KV_PAIR(name, type_key, type_val)  \
-    struct ____btf_map_##name {                         \
-        type_key key;                                   \
-        type_val value;                                 \
-    };                                                  \
-    struct ____btf_map_##name                           \
-        __attribute__ ((section(".maps." #name), used)) \
-        ____btf_map_##name = {};
-
 #define REGISTER_START()
-#ifndef BTF
-/// Note: pinning exports the table name globally, do not remove.
-#define REGISTER_TABLE(NAME, TYPE, KEY_TYPE, VALUE_TYPE, MAX_ENTRIES) \
-struct bpf_elf_map SEC("maps") NAME = {          \
-    .type        = TYPE,               \
-    .size_key    = sizeof(KEY_TYPE),   \
-    .size_value  = sizeof(VALUE_TYPE), \
-    .max_elem    = MAX_ENTRIES,        \
-    .pinning     = 2,                  \
-    .flags       = 0,                  \
-};
-#define REGISTER_TABLE_INNER(NAME, TYPE, KEY_TYPE, VALUE_TYPE, MAX_ENTRIES, ID, INNER_IDX) \
-struct bpf_elf_map SEC("maps") NAME = {          \
-    .type        = TYPE,               \
-    .size_key    = sizeof(KEY_TYPE),   \
-    .size_value  = sizeof(VALUE_TYPE), \
-    .max_elem    = MAX_ENTRIES,        \
-    .pinning     = 2,                  \
-    .flags       = 0,                  \
-    .id          = ID,                 \
-    .inner_idx   = INNER_IDX,          \
-};
-#define REGISTER_TABLE_OUTER(NAME, TYPE, KEY_TYPE, VALUE_TYPE, MAX_ENTRIES, INNER_ID, INNER_NAME) \
-struct bpf_elf_map SEC("maps") NAME = {          \
-    .type        = TYPE,               \
-    .size_key    = sizeof(KEY_TYPE),   \
-    .size_value  = sizeof(VALUE_TYPE), \
-    .max_elem    = MAX_ENTRIES,        \
-    .pinning     = 2,                  \
-    .flags       = 0,                  \
-    .inner_id    = INNER_ID,           \
-};
-#define REGISTER_TABLE_FLAGS(NAME, TYPE, KEY_TYPE, VALUE_TYPE, MAX_ENTRIES, FLAGS) \
-struct bpf_elf_map SEC("maps") NAME = {          \
-    .type        = TYPE,               \
-    .size_key    = sizeof(KEY_TYPE),   \
-    .size_value  = sizeof(VALUE_TYPE), \
-    .max_elem    = MAX_ENTRIES,        \
-    .pinning     = 2,                  \
-    .flags       = FLAGS,              \
-};
-#else
 #define REGISTER_TABLE(NAME, TYPE, KEY_TYPE, VALUE_TYPE, MAX_ENTRIES) \
 struct {                                 \
     __uint(type, TYPE);                  \
     KEY_TYPE *key;                       \
     VALUE_TYPE *value;                   \
     __uint(max_entries, MAX_ENTRIES);    \
-    __uint(pinning, LIBBPF_PIN_BY_NAME); \
 } NAME SEC(".maps");
 #define REGISTER_TABLE_FLAGS(NAME, TYPE, KEY_TYPE, VALUE_TYPE, MAX_ENTRIES, FLAGS) \
 struct {                                 \
     __uint(type, TYPE);                  \
     KEY_TYPE *key;                       \
     VALUE_TYPE *value;                   \
     __uint(max_entries, MAX_ENTRIES);    \
-    __uint(pinning, LIBBPF_PIN_BY_NAME); \
     __uint(map_flags, FLAGS);            \
 } NAME SEC(".maps");
 #define REGISTER_TABLE_INNER(NAME, TYPE, KEY_TYPE, VALUE_TYPE, MAX_ENTRIES, ID, INNER_IDX) \
@@ -162,18 +93,17 @@ struct {                                 \
     KEY_TYPE *key;                       \
     VALUE_TYPE *value;                   \
     __uint(max_entries, MAX_ENTRIES);    \
-    __uint(pinning, LIBBPF_PIN_BY_NAME); \
     __array(values, struct INNER_NAME);  \
-} NAME SEC(".maps");
+} NAME SEC(".maps") = {                  \
+        .values = { &INNER_NAME }        \
+};
 #define REGISTER_TABLE_NO_KEY_TYPE(NAME, TYPE, KEY_SIZE, VALUE_TYPE, MAX_ENTRIES) \
 struct {                                 \
     __uint(type, TYPE);                  \
     __uint(key_size, KEY_SIZE);          \
     VALUE_TYPE *value;                   \
     __uint(max_entries, MAX_ENTRIES);    \
-    __uint(pinning, LIBBPF_PIN_BY_NAME); \
 } NAME SEC(".maps");
-#endif
 #define REGISTER_END()
 
 #define BPF_MAP_LOOKUP_ELEM(table, key) \
diff --git a/backends/ebpf/runtime/kernel.mk b/backends/ebpf/runtime/kernel.mk
@@ -3,7 +3,7 @@ ROOT_DIR := $(dir $(abspath $(lastword $(MAKEFILE_LIST))))
 # Argument for the CLANG compiler
 LLC ?= llc
 CLANG ?= clang
-override INCLUDES+= -I$(ROOT_DIR) -I$(ROOT_DIR)usr/include/ -I$(ROOT_DIR)contrib/libbpf/include/uapi/
+override INCLUDES+= -I$(ROOT_DIR) -I$(ROOT_DIR)usr/include/ -I$(ROOT_DIR)install/libbpf/include/
 override LIBS+=
 # Optimization flags to save space
 override CFLAGS+= -O2 -g -c -D__KERNEL__ -D__ASM_SYSREG_H \
diff --git a/backends/ebpf/target.cpp b/backends/ebpf/target.cpp
@@ -98,7 +98,6 @@ void KernelSamplesTarget::emitTableDecl(Util::SourceCodeBuilder *builder, cstrin
                               flags);
     }
     builder->newline();
-    annotateTableWithBTF(builder, tblName, keyType, valueType);
 }
 
 void KernelSamplesTarget::emitTableDeclSpinlock(Util::SourceCodeBuilder *builder, cstring tblName,
@@ -131,14 +130,12 @@ void KernelSamplesTarget::emitMapInMapDecl(Util::SourceCodeBuilder *builder, cst
     builder->appendFormat(registerInnerTable, innerName, kind, innerKeyType, innerValueType,
                           innerSize, innerMapIndex, innerMapIndex);
     builder->newline();
-    annotateTableWithBTF(builder, innerName, innerKeyType, innerValueType);
 
     kind = getBPFMapType(outerTableKind);
     cstring keyType = outerTableKind == TableArray ? "__u32"_cs : outerKeyType;
     builder->appendFormat(registerOuterTable, outerName, kind, keyType, "__u32", outerSize,
                           innerMapIndex, innerName);
     builder->newline();
-    annotateTableWithBTF(builder, outerName, keyType, "__u32"_cs);
 }
 
 void KernelSamplesTarget::emitLicense(Util::SourceCodeBuilder *builder, cstring license) const {
@@ -202,12 +199,6 @@ void KernelSamplesTarget::emitTraceMessage(Util::SourceCodeBuilder *builder, con
     builder->newline();
 }
 
-void KernelSamplesTarget::annotateTableWithBTF(Util::SourceCodeBuilder *builder, cstring name,
-                                               cstring keyType, cstring valueType) const {
-    builder->appendFormat("BPF_ANNOTATE_KV_PAIR(%v, %v, %v)", name, keyType, valueType);
-    builder->newline();
-}
-
 //////////////////////////////////////////////////////////////
 void XdpTarget::emitResizeBuffer(Util::SourceCodeBuilder *builder, cstring buffer,
                                  cstring offsetVar) const {
diff --git a/backends/ebpf/target.h b/backends/ebpf/target.h
@@ -195,9 +195,6 @@ class KernelSamplesTarget : public Target {
     cstring sysMapPath() const override { return "/sys/fs/bpf/tc/globals"_cs; }
 
     cstring packetDescriptorType() const override { return "struct __sk_buff"_cs; }
-
-    void annotateTableWithBTF(Util::SourceCodeBuilder *builder, cstring name, cstring keyType,
-                              cstring valueType) const;
 };
 
 class P4TCTarget : public KernelSamplesTarget {
diff --git a/backends/ebpf/targets/ebpfenv.py b/backends/ebpf/targets/ebpfenv.py
@@ -96,7 +96,7 @@ def ns_proc_append(self, proc: subprocess.Popen, cmd: str) -> int:
     def ns_proc_close(self, proc: subprocess.Popen, **extra_args: Any) -> int:
         """Close and actually run the process in the namespace. Returns the
         exit code."""
-        testutils.log.info("Executing command: %s", proc)
+        testutils.log.info("Executing command: %s", proc.args)
         result = testutils.run_process(proc, timeout=testutils.TIMEOUT, **extra_args)
         if result.returncode != testutils.SUCCESS:
             testutils.log.error(
@@ -109,7 +109,7 @@ def _configure_bridge(self, br_name: str) -> int:
         avoid ICMPv6 spam."""
         # We do not care about failures here
         self.ns_exec(f"ip link set dev {br_name} up")
-        self.ns_exec(f"ip link set dev {br_name} mtu 9000")
+        self.ns_exec(f"ip link set dev {br_name} mtu 1500")
         # Prevent the broadcasting of ipv6 link discovery messages
         self.ns_exec("sysctl -w net.ipv6.conf.all.disable_ipv6=1")
         self.ns_exec("sysctl -w net.ipv6.conf.default.disable_ipv6=1")
@@ -130,7 +130,7 @@ def _configure_bridge_port(self, port_name: str) -> int:
         result = self.ns_exec(cmd)
         if result != testutils.SUCCESS:
             return result
-        cmd = f"ip link set dev {port_name} mtu 9000"
+        cmd = f"ip link set dev {port_name} mtu 1500"
         return self.ns_exec(cmd)
 
     def attach_interfaces(self, num_ifaces: int) -> int:
diff --git a/backends/ebpf/targets/kernel_target.py b/backends/ebpf/targets/kernel_target.py
diff --git a/testdata/extern_modules/extern-conntrack-ebpf.c b/testdata/extern_modules/extern-conntrack-ebpf.c
