Merge pull request #127 from iovisor/bblanco_dev

Changes to support map entry read/write in fuse

src/cc/bpf_common.cc

@@ -104,6 +104,12 @@ size_t bpf_num_tables(void *program) {
   return mod->num_tables();
 }
 
+size_t bpf_table_id(void *program, const char *table_name) {
+  auto mod = static_cast<ebpf::BPFModule *>(program);
+  if (!mod) return ~0ull;
+  return mod->table_id(table_name);
+}
+
 int bpf_table_fd(void *program, const char *table_name) {
   auto mod = static_cast<ebpf::BPFModule *>(program);
   if (!mod) return -1;
@@ -170,27 +176,26 @@ size_t bpf_table_leaf_size_id(void *program, size_t id) {
   return mod->table_leaf_size(id);
 }
 
-int bpf_table_update(void *program, const char *table_name, const char *key, const char *leaf) {
+int bpf_table_key_snprintf(void *program, size_t id, char *buf, size_t buflen, const void *key) {
   auto mod = static_cast<ebpf::BPFModule *>(program);
-  if (!mod) return 0;
-  return mod->table_update(table_name, key, leaf);
+  if (!mod) return -1;
+  return mod->table_key_printf(id, buf, buflen, key);
 }
-
-int bpf_table_update_id(void *program, size_t id, const char *key, const char *leaf) {
+int bpf_table_leaf_snprintf(void *program, size_t id, char *buf, size_t buflen, const void *leaf) {
   auto mod = static_cast<ebpf::BPFModule *>(program);
-  if (!mod) return 0;
-  return mod->table_update(id, key, leaf);
+  if (!mod) return -1;
+  return mod->table_leaf_printf(id, buf, buflen, leaf);
 }
 
-int bpf_table_key_snprintf(void *program, size_t id, char *buf, size_t buflen, const void *key) {
+int bpf_table_key_sscanf(void *program, size_t id, const char *buf, void *key) {
   auto mod = static_cast<ebpf::BPFModule *>(program);
-  if (!mod) return 0;
-  return mod->table_key_printf(id, buf, buflen, key);
+  if (!mod) return -1;
+  return mod->table_key_scanf(id, buf, key);
 }
-int bpf_table_leaf_snprintf(void *program, size_t id, char *buf, size_t buflen, const void *leaf) {
+int bpf_table_leaf_sscanf(void *program, size_t id, const char *buf, void *leaf) {
   auto mod = static_cast<ebpf::BPFModule *>(program);
-  if (!mod) return 0;
-  return mod->table_key_printf(id, buf, buflen, leaf);
+  if (!mod) return -1;
+  return mod->table_leaf_scanf(id, buf, leaf);
 }
 
 }

src/cc/bpf_common.h

@@ -37,6 +37,7 @@ void * bpf_function_start(void *program, const char *name);
 size_t bpf_function_size_id(void *program, size_t id);
 size_t bpf_function_size(void *program, const char *name);
 size_t bpf_num_tables(void *program);
+size_t bpf_table_id(void *program, const char *table_name);
 int bpf_table_fd(void *program, const char *table_name);
 int bpf_table_fd_id(void *program, size_t id);
 const char * bpf_table_name(void *program, size_t id);
@@ -50,10 +51,8 @@ size_t bpf_table_leaf_size(void *program, const char *table_name);
 size_t bpf_table_leaf_size_id(void *program, size_t id);
 int bpf_table_key_snprintf(void *program, size_t id, char *buf, size_t buflen, const void *key);
 int bpf_table_leaf_snprintf(void *program, size_t id, char *buf, size_t buflen, const void *leaf);
-//int bpf_table_key_sscanf(void *program, size_t id, const char *buf, void *key);
-//int bpf_table_leaf_sscanf(void *program, size_t id, const char *buf, void *leaf);
-int bpf_table_update(void *program, const char *table_name, const char *key, const char *leaf);
-int bpf_table_update_id(void *program, size_t id, const char *key, const char *leaf);
+int bpf_table_key_sscanf(void *program, size_t id, const char *buf, void *key);
+int bpf_table_leaf_sscanf(void *program, size_t id, const char *buf, void *leaf);
 
 #ifdef __cplusplus
 }

src/cc/bpf_module.h

@@ -64,6 +64,7 @@ class BPFModule {
   size_t function_size(size_t id) const;
   size_t function_size(const std::string &name) const;
   size_t num_tables() const;
+  size_t table_id(const std::string &name) const;
   int table_fd(size_t id) const;
   int table_fd(const std::string &name) const;
   const char * table_name(size_t id) const;
@@ -72,13 +73,13 @@ class BPFModule {
   size_t table_key_size(size_t id) const;
   size_t table_key_size(const std::string &name) const;
   int table_key_printf(size_t id, char *buf, size_t buflen, const void *key);
+  int table_key_scanf(size_t id, const char *buf, void *key);
   const char * table_leaf_desc(size_t id) const;
   const char * table_leaf_desc(const std::string &name) const;
   size_t table_leaf_size(size_t id) const;
   size_t table_leaf_size(const std::string &name) const;
   int table_leaf_printf(size_t id, char *buf, size_t buflen, const void *leaf);
-  int table_update(size_t id, const char *key, const char *leaf);
-  int table_update(const std::string &name, const char *key, const char *leaf);
+  int table_leaf_scanf(size_t id, const char *buf, void *leaf);
   char * license() const;
   unsigned kern_version() const;
  private:

src/cc/table_desc.h

@@ -31,10 +31,10 @@ struct TableDesc {
   size_t max_entries;
   std::string key_desc;
   std::string leaf_desc;
-  llvm::Function *key_reader;
-  llvm::Function *leaf_reader;
-  llvm::Function *key_writer;
-  llvm::Function *leaf_writer;
+  llvm::Function *key_sscanf;
+  llvm::Function *leaf_sscanf;
+  llvm::Function *key_snprintf;
+  llvm::Function *leaf_snprintf;
 };
 
 }  // namespace ebpf

src/python/bpf/__init__.py

@@ -39,14 +39,26 @@ lib.bpf_function_start.restype = ct.c_void_p
 lib.bpf_function_start.argtypes = [ct.c_void_p, ct.c_char_p]
 lib.bpf_function_size.restype = ct.c_size_t
 lib.bpf_function_size.argtypes = [ct.c_void_p, ct.c_char_p]
+lib.bpf_table_id.restype = ct.c_ulonglong
+lib.bpf_table_id.argtypes = [ct.c_void_p, ct.c_char_p]
 lib.bpf_table_fd.restype = ct.c_int
 lib.bpf_table_fd.argtypes = [ct.c_void_p, ct.c_char_p]
 lib.bpf_table_key_desc.restype = ct.c_char_p
 lib.bpf_table_key_desc.argtypes = [ct.c_void_p, ct.c_char_p]
 lib.bpf_table_leaf_desc.restype = ct.c_char_p
 lib.bpf_table_leaf_desc.argtypes = [ct.c_void_p, ct.c_char_p]
-lib.bpf_table_update.restype = ct.c_int
-lib.bpf_table_update.argtypes = [ct.c_void_p, ct.c_char_p, ct.c_char_p, ct.c_char_p]
+lib.bpf_table_key_snprintf.restype = ct.c_int
+lib.bpf_table_key_snprintf.argtypes = [ct.c_void_p, ct.c_ulonglong,
+        ct.c_char_p, ct.c_ulonglong, ct.c_void_p]
+lib.bpf_table_leaf_snprintf.restype = ct.c_int
+lib.bpf_table_leaf_snprintf.argtypes = [ct.c_void_p, ct.c_ulonglong,
+        ct.c_char_p, ct.c_ulonglong, ct.c_void_p]
+lib.bpf_table_key_sscanf.restype = ct.c_int
+lib.bpf_table_key_sscanf.argtypes = [ct.c_void_p, ct.c_ulonglong,
+        ct.c_char_p, ct.c_void_p]
+lib.bpf_table_leaf_sscanf.restype = ct.c_int
+lib.bpf_table_leaf_sscanf.argtypes = [ct.c_void_p, ct.c_ulonglong,
+        ct.c_char_p, ct.c_void_p]
 
 # keep in sync with libbpf.h
 lib.bpf_get_next_key.restype = ct.c_int
@@ -92,12 +104,49 @@ class BPF(object):
             self.fd = fd
 
     class Table(MutableMapping):
-        def __init__(self, bpf, map_fd, keytype, leaftype):
+        def __init__(self, bpf, map_id, map_fd, keytype, leaftype):
             self.bpf = bpf
+            self.map_id = map_id
             self.map_fd = map_fd
             self.Key = keytype
             self.Leaf = leaftype
 
+        def key_sprintf(self, key):
+            key_p = ct.pointer(key)
+            buf = ct.create_string_buffer(ct.sizeof(self.Key) * 8)
+            res = lib.bpf_table_key_snprintf(self.bpf.module, self.map_id,
+                    buf, len(buf), key_p)
+            if res < 0:
+                raise Exception("Could not printf key")
+            return buf.value
+
+        def leaf_sprintf(self, leaf):
+            leaf_p = ct.pointer(leaf)
+            buf = ct.create_string_buffer(ct.sizeof(self.Leaf) * 8)
+            res = lib.bpf_table_leaf_snprintf(self.bpf.module, self.map_id,
+                    buf, len(buf), leaf_p)
+            if res < 0:
+                raise Exception("Could not printf leaf")
+            return buf.value
+
+        def key_scanf(self, key_str):
+            key = self.Key()
+            key_p = ct.pointer(key)
+            res = lib.bpf_table_key_sscanf(self.bpf.module, self.map_id,
+                    key_str, key_p)
+            if res < 0:
+                raise Exception("Could not scanf key")
+            return key
+
+        def leaf_scanf(self, leaf_str):
+            leaf = self.Leaf()
+            leaf_p = ct.pointer(leaf)
+            res = lib.bpf_table_leaf_sscanf(self.bpf.module, self.map_id,
+                    leaf_str, leaf_p)
+            if res < 0:
+                raise Exception("Could not scanf leaf")
+            return leaf
+
         def __getitem__(self, key):
             key_p = ct.pointer(key)
             leaf = self.Leaf()
@@ -245,6 +294,7 @@ class BPF(object):
         return cls
 
     def get_table(self, name, keytype=None, leaftype=None):
+        map_id = lib.bpf_table_id(self.module, name.encode("ascii"))
         map_fd = lib.bpf_table_fd(self.module, name.encode("ascii"))
         if map_fd < 0:
             raise Exception("Failed to find BPF Table %s" % name)
@@ -258,13 +308,7 @@ class BPF(object):
             if not leaf_desc:
                 raise Exception("Failed to load BPF Table %s leaf desc" % name)
             leaftype = BPF._decode_table_type(json.loads(leaf_desc.decode()))
-        return BPF.Table(self, map_fd, keytype, leaftype)
-
-    def update_table(self, name, key, leaf):
-        res = lib.bpf_table_update(self.module, name.encode("ascii"), key.encode("ascii"),
-                leaf.encode("ascii"))
-        if res < 0:
-            raise Exception("update_table failed")
+        return BPF.Table(self, map_id, map_fd, keytype, leaftype)
 
     @staticmethod
     def attach_raw_socket(fn, dev):

tests/cc/test_clang.py

@@ -55,9 +55,11 @@ int foo(void *ctx) {
 """
         b = BPF(text=text, debug=0)
         fn = b.load_func("foo", BPF.KPROBE)
-        b.update_table("stats", "2", "{ 2 3 0x1000000004 { 5 6 }}")
         t = b.get_table("stats")
-        l = t[t.Key(2)]
+        s1 = t.key_sprintf(t.Key(2))
+        self.assertEqual(s1, b"0x2")
+        s2 = t.leaf_sprintf(t.Leaf(2, 3, 4, 1, (5, 6)))
+        l = t.leaf_scanf(s2)
         self.assertEqual(l.a, 2)
         self.assertEqual(l.b, 3)
         self.assertEqual(l.c, 4)