MT#61856 control_ng: add func for command lookup

Instead of the previous approach using the strhash,
introduce if-based lookup from `NG_COMMANDS`.

The usage of strhash is deprecated because it:
- forses string literals in switch cases, hence gives
  no possibility to use variables
- makes then shortcuts using macro not possible to be used
- it makes the part with the command find and
  actual commands definition duplicate, because
  one has to maintain both of them when adding/removing commands
- switch is redundant and feels heavy, meanwhile the same
  thing can be generated using marco based on `NG_COMMANDS`
  introduced before, which are the main source of the truth

Newer approach:
- avoid usage of for/while cycles (because CPU consuming)
- sorts the lookup based on the cmd name (string) length,
  what makes the command find efficient, because exlcludes
  unnecessary comparisons
- uses the `memcmp()` at the very last
- for example, for the "offer" command it may run the `memcmp()`
  only two times, because there are only two commands with
  the length 5 our of supported 35 commands in list now

Additionally:
include `string.h` for `memcmp()` operations.

Change-Id: Iae70de87b88cd444ae162ba2b7c6aa7690731ee3

daemon/control_ng.c

@@ -16,6 +16,7 @@
 #include "statistics.h"
 #include "streambuf.h"
 #include "homer.h"
+#include <string.h>
 
 mutex_t rtpe_cngs_lock;
 mutex_t tcp_connections_lock;
@@ -55,6 +56,26 @@ static const struct ng_command_def ng_command_defs[OP_COUNT] = {
 #undef X
 };
 
+static const struct ng_command_def *ng_command_find(const str *cmd) {
+	if (!cmd || !cmd->s)
+		return NULL;
+
+#define X(op, name, esc, short_name, handler) \
+	if (cmd->len == sizeof(name) - 1 && !memcmp(cmd->s, name, sizeof(name) - 1)) \
+		return &ng_command_defs[op];
+
+#define XA(op, name, esc, short_name, handler) \
+	if (cmd->len == sizeof(name) - 1 && !memcmp(cmd->s, name, sizeof(name) - 1)) \
+		return &ng_command_defs[op];
+
+	NG_COMMANDS(X, XA)
+
+#undef XA
+#undef X
+
+	return NULL;
+}
+
 const char *ng_command_strings[OP_COUNT] = {
 #define X(op, name, esc, short_name, handler) [op] = name,
 #define XA(op, name, esc, short_name, handler) [op] = name,