Support for hardware offload (iovisor#2502)

 Support for hardware offload
 Update XDP example to support HW offload

Signed-off-by: Paul Chaignon <[email protected]>

examples/networking/xdp/xdp_drop_count.py

@@ -16,24 +16,29 @@
 def usage():
  print("Usage: {0} [-S] <ifdev>".format(sys.argv[0]))
  print(" -S: use skb mode\n")
+ print(" -H: use hardware offload mode\n")
  print("e.g.: {0} eth0\n".format(sys.argv[0]))
  exit(1)
 
 if len(sys.argv) < 2 or len(sys.argv) > 3:
  usage()
 
+offload_device = None
 if len(sys.argv) == 2:
  device = sys.argv[1]
+elif len(sys.argv) == 3:
+ device = sys.argv[2]
 
+maptype = "percpu_array"
 if len(sys.argv) == 3:
  if "-S" in sys.argv:
  # XDP_FLAGS_SKB_MODE
- flags |= 2 << 0
-
- if "-S" == sys.argv[1]:
- device = sys.argv[2]
- else:
- device = sys.argv[1]
+ flags |= (1 << 1)
+ if "-H" in sys.argv:
+  # XDP_FLAGS_HW_MODE
+ maptype = "array"
+  offload_device = device
+ flags |= (1 << 3)
 
 mode = BPF.XDP
 #mode = BPF.SCHED_CLS
@@ -56,8 +61,7 @@ def usage():
 #include <linux/ip.h>
 #include <linux/ipv6.h>
 
-
-BPF_TABLE("percpu_array", uint32_t, long, dropcnt, 256);
+BPF_TABLE(MAPTYPE, uint32_t, long, dropcnt, 256);
 
 static inline int parse_ipv4(void *data, u64 nh_off, void *data_end) {
  struct iphdr *iph = data + nh_off;
@@ -119,13 +123,15 @@ def usage():
 
  value = dropcnt.lookup(&index);
  if (value)
- *value += 1;
+ __sync_fetch_and_add(value, 1);
 
  return rc;
 }
-""", cflags=["-w", "-DRETURNCODE=%s" % ret, "-DCTXTYPE=%s" % ctxtype])
+""", cflags=["-w", "-DRETURNCODE=%s" % ret, "-DCTXTYPE=%s" % ctxtype,
+ "-DMAPTYPE=\"%s\"" % maptype],
+ device=offload_device)
 
-fn = b.load_func("xdp_prog1", mode)
+fn = b.load_func("xdp_prog1", mode, offload_device)
 
 if mode == BPF.XDP:
  b.attach_xdp(device, fn, flags)
@@ -143,7 +149,7 @@ def usage():
 while 1:
  try:
  for k in dropcnt.keys():
- val = dropcnt.sum(k).value
+ val = dropcnt[k].value if maptype == "array" else dropcnt.sum(k).value
  i = k.value
  if val:
  delta = val - prev[i]

src/cc/bcc_common.cc

@@ -17,8 +17,9 @@
 #include "bpf_module.h"
 
 extern "C" {
-void * bpf_module_create_b(const char *filename, const char *proto_filename, unsigned flags) {
- auto mod = new ebpf::BPFModule(flags);
+void * bpf_module_create_b(const char *filename, const char *proto_filename, unsigned flags,
+ const char *dev_name) {
+ auto mod = new ebpf::BPFModule(flags, nullptr, true, "", true, dev_name);
  if (mod->load_b(filename, proto_filename) != 0) {
  delete mod;
  return nullptr;
@@ -27,8 +28,8 @@ void * bpf_module_create_b(const char *filename, const char *proto_filename, uns
 }
 
 void * bpf_module_create_c(const char *filename, unsigned flags, const char *cflags[],
- int ncflags, bool allow_rlimit) {
- auto mod = new ebpf::BPFModule(flags, nullptr, true, "", allow_rlimit);
+ int ncflags, bool allow_rlimit, const char *dev_name) {
+ auto mod = new ebpf::BPFModule(flags, nullptr, true, "", allow_rlimit, dev_name);
  if (mod->load_c(filename, cflags, ncflags) != 0) {
  delete mod;
  return nullptr;
@@ -37,8 +38,8 @@ void * bpf_module_create_c(const char *filename, unsigned flags, const char *cfl
 }
 
 void * bpf_module_create_c_from_string(const char *text, unsigned flags, const char *cflags[],
- int ncflags, bool allow_rlimit) {
- auto mod = new ebpf::BPFModule(flags, nullptr, true, "", allow_rlimit);
+ int ncflags, bool allow_rlimit, const char *dev_name) {
+ auto mod = new ebpf::BPFModule(flags, nullptr, true, "", allow_rlimit, dev_name);
  if (mod->load_string(text, cflags, ncflags) != 0) {
  delete mod;
  return nullptr;
@@ -240,12 +241,13 @@ int bpf_table_leaf_sscanf(void *program, size_t id, const char *buf, void *leaf)
 int bcc_func_load(void *program, int prog_type, const char *name,
  const struct bpf_insn *insns, int prog_len,
  const char *license, unsigned kern_version,
- int log_level, char *log_buf, unsigned log_buf_size) {
+ int log_level, char *log_buf, unsigned log_buf_size,
+ const char *dev_name) {
  auto mod = static_cast<ebpf::BPFModule *>(program);
  if (!mod) return -1;
  return mod->bcc_func_load(prog_type, name, insns, prog_len,
  license, kern_version, log_level,
- log_buf, log_buf_size);
+ log_buf, log_buf_size, dev_name);
 
 }
 

src/cc/bcc_common.h

@@ -25,11 +25,13 @@
 extern "C" {
 #endif
 
-void * bpf_module_create_b(const char *filename, const char *proto_filename, unsigned flags);
+void * bpf_module_create_b(const char *filename, const char *proto_filename, unsigned flags,
+ const char *dev_name);
 void * bpf_module_create_c(const char *filename, unsigned flags, const char *cflags[], int ncflags,
- bool allow_rlimit);
+ bool allow_rlimit, const char *dev_name);
 void * bpf_module_create_c_from_string(const char *text, unsigned flags, const char *cflags[],
- int ncflags, bool allow_rlimit);
+ int ncflags, bool allow_rlimit,
+ const char *dev_name);
 void bpf_module_destroy(void *program);
 char * bpf_module_license(void *program);
 unsigned bpf_module_kern_version(void *program);
@@ -69,7 +71,8 @@ struct bpf_insn;
 int bcc_func_load(void *program, int prog_type, const char *name,
  const struct bpf_insn *insns, int prog_len,
  const char *license, unsigned kern_version,
- int log_level, char *log_buf, unsigned log_buf_size);
+ int log_level, char *log_buf, unsigned log_buf_size,
+ const char *dev_name);
 
 #ifdef __cplusplus
 }

src/cc/bpf_module.cc

@@ -20,6 +20,7 @@
 #include <unistd.h>
 #include <vector>
 #include <linux/bpf.h>
+#include <net/if.h>
 
 #include <llvm/ExecutionEngine/MCJIT.h>
 #include <llvm/ExecutionEngine/SectionMemoryManager.h>
@@ -93,7 +94,8 @@ class MyMemoryManager : public SectionMemoryManager {
 };
 
 BPFModule::BPFModule(unsigned flags, TableStorage *ts, bool rw_engine_enabled,
- const std::string &maps_ns, bool allow_rlimit)
+ const std::string &maps_ns, bool allow_rlimit,
+ const char *dev_name)
  : flags_(flags),
  rw_engine_enabled_(rw_engine_enabled && bpf_module_rw_engine_enabled()),
  used_b_loader_(false),
@@ -102,6 +104,7 @@ BPFModule::BPFModule(unsigned flags, TableStorage *ts, bool rw_engine_enabled,
  id_(std::to_string((uintptr_t)this)),
  maps_ns_(maps_ns),
  ts_(ts), btf_(nullptr) {
+ ifindex_ = dev_name ? if_nametoindex(dev_name) : 0;
  initialize_rw_engine();
  LLVMInitializeBPFTarget();
  LLVMInitializeBPFTargetMC();
@@ -338,6 +341,7 @@ int BPFModule::load_maps(sec_map_def &sections) {
  attr.value_size = value_size;
  attr.max_entries = max_entries;
  attr.map_flags = map_flags;
+ attr.map_ifindex = ifindex_;
 
  if (map_tids.find(map_name) != map_tids.end()) {
  attr.btf_fd = btf_->get_fd();
@@ -847,7 +851,8 @@ int BPFModule::load_string(const string &text, const char *cflags[], int ncflags
 int BPFModule::bcc_func_load(int prog_type, const char *name,
  const struct bpf_insn *insns, int prog_len,
  const char *license, unsigned kern_version,
- int log_level, char *log_buf, unsigned log_buf_size) {
+ int log_level, char *log_buf, unsigned log_buf_size,
+ const char *dev_name) {
  struct bpf_load_program_attr attr = {};
  unsigned func_info_cnt, line_info_cnt, finfo_rec_size, linfo_rec_size;
  void *func_info = NULL, *line_info = NULL;
@@ -859,6 +864,8 @@ int BPFModule::bcc_func_load(int prog_type, const char *name,
  attr.license = license;
  attr.kern_version = kern_version;
  attr.log_level = log_level;
+ if (dev_name)
+ attr.prog_ifindex = if_nametoindex(dev_name);
 
  if (btf_) {
  int btf_fd = btf_->get_fd();

src/cc/bpf_module.h

@@ -91,7 +91,8 @@ class BPFModule {
 
  public:
  BPFModule(unsigned flags, TableStorage *ts = nullptr, bool rw_engine_enabled = true,
- const std::string &maps_ns = "", bool allow_rlimit = true);
+ const std::string &maps_ns = "", bool allow_rlimit = true,
+ const char *dev_name = nullptr);
  ~BPFModule();
  int free_bcc_memory();
  int load_b(const std::string &filename, const std::string &proto_filename);
@@ -138,7 +139,8 @@ class BPFModule {
  int bcc_func_load(int prog_type, const char *name,
  const struct bpf_insn *insns, int prog_len,
  const char *license, unsigned kern_version,
- int log_level, char *log_buf, unsigned log_buf_size);
+ int log_level, char *log_buf, unsigned log_buf_size,
+ const char *dev_name = nullptr);
  size_t perf_event_fields(const char *) const;
  const char * perf_event_field(const char *, size_t i) const;
 
@@ -168,6 +170,7 @@ class BPFModule {
  std::unique_ptr<TableStorage> local_ts_;
  BTF *btf_;
  fake_fd_map_def fake_fd_map_;
+ unsigned int ifindex_;
 
  // map of events -- key: event name, value: event fields
  std::map<std::string, std::vector<std::string>> perf_events_;

src/python/bcc/__init__.py

@@ -276,7 +276,7 @@ def is_exe(fpath):
  return None
 
  def __init__(self, src_file=b"", hdr_file=b"", text=None, debug=0,
- cflags=[], usdt_contexts=[], allow_rlimit=True):
+ cflags=[], usdt_contexts=[], allow_rlimit=True, device=None):
  """Create a new BPF module with the given source code.
 
  Note:
@@ -319,7 +319,7 @@ def __init__(self, src_file=b"", hdr_file=b"", text=None, debug=0,
 
  # files that end in ".b" are treated as B files. Everything else is a (BPF-)C file
  if src_file.endswith(b".b"):
- self.module = lib.bpf_module_create_b(src_file, hdr_file, self.debug)
+ self.module = lib.bpf_module_create_b(src_file, hdr_file, self.debug, device)
  else:
  if src_file:
  # Read the BPF C source file into the text variable. This ensures,
@@ -342,7 +342,7 @@ def __init__(self, src_file=b"", hdr_file=b"", text=None, debug=0,
  self.module = lib.bpf_module_create_c_from_string(text,
  self.debug,
  cflags_array, len(cflags_array),
- allow_rlimit)
+ allow_rlimit, device)
  if not self.module:
  raise Exception("Failed to compile BPF module %s" % (src_file or "<text>"))
 
@@ -367,7 +367,7 @@ def load_funcs(self, prog_type=KPROBE):
 
  return fns
 
- def load_func(self, func_name, prog_type):
+ def load_func(self, func_name, prog_type, device = None):
  func_name = _assert_is_bytes(func_name)
  if func_name in self.funcs:
  return self.funcs[func_name]
@@ -383,7 +383,7 @@ def load_func(self, func_name, prog_type):
  lib.bpf_function_size(self.module, func_name),
  lib.bpf_module_license(self.module),
  lib.bpf_module_kern_version(self.module),
- log_level, None, 0);
+ log_level, None, 0, device);
 
  if fd < 0:
  atexit.register(self.donothing)

src/python/bcc/libbcc.py

@@ -18,13 +18,14 @@
 
 # keep in sync with bcc_common.h
 lib.bpf_module_create_b.restype = ct.c_void_p
-lib.bpf_module_create_b.argtypes = [ct.c_char_p, ct.c_char_p, ct.c_uint]
+lib.bpf_module_create_b.argtypes = [ct.c_char_p, ct.c_char_p, ct.c_uint,
+ ct.c_char_p]
 lib.bpf_module_create_c.restype = ct.c_void_p
 lib.bpf_module_create_c.argtypes = [ct.c_char_p, ct.c_uint,
- ct.POINTER(ct.c_char_p), ct.c_int, ct.c_bool]
+ ct.POINTER(ct.c_char_p), ct.c_int, ct.c_bool, ct.c_char_p]
 lib.bpf_module_create_c_from_string.restype = ct.c_void_p
 lib.bpf_module_create_c_from_string.argtypes = [ct.c_char_p, ct.c_uint,
- ct.POINTER(ct.c_char_p), ct.c_int, ct.c_bool]
+ ct.POINTER(ct.c_char_p), ct.c_int, ct.c_bool, ct.c_char_p]
 lib.bpf_module_destroy.restype = None
 lib.bpf_module_destroy.argtypes = [ct.c_void_p]
 lib.bpf_module_license.restype = ct.c_char_p

tests/cc/test_static.c

@@ -1,6 +1,6 @@
 #include "bcc_common.h"
 
 int main(int argc, char **argv) {
- void *mod = bpf_module_create_c_from_string("BPF_TABLE(\"array\", int, int, stats, 10);\n", 4, NULL, 0, true);
+ void *mod = bpf_module_create_c_from_string("BPF_TABLE(\"array\", int, int, stats, 10);\n", 4, NULL, 0, true, NULL);
  return !(mod != NULL);
 }