diff --git a/src/commands.h b/src/commands.h
index 489bb51..fe1b0df 100644
--- a/src/commands.h
+++ b/src/commands.h
@@ -7,36 +7,70 @@
 #ifndef F2B_COMMANDS_H_
 #define F2B_COMMANDS_H_
 
-/* yes, i know about LINE_MAX */
+/**
+ * @file
+ * This header contains definition of control commands and routines
+ * for work with data buffer of control message
+ */
+
+/**
+ * Maximum length of input line in client
+ * @note yes, i know about LINE_MAX
+ */
 #define INPUT_LINE_MAX 256
+/** Maximum count of data pieces in control message data buf */
 #define CMD_TOKENS_MAX 6
 
+/** control command type */
 enum f2b_cmd_type {
-  CMD_NONE = 0,
-  CMD_RESP,
-  CMD_HELP,
-  CMD_PING = 8,
-  CMD_STATUS,
-  CMD_ROTATE,
-  CMD_RELOAD,
-  CMD_SHUTDOWN,
-  CMD_JAIL_STATUS = 16,
-  CMD_JAIL_SET,
-  CMD_JAIL_IP_STATUS,
-  CMD_JAIL_IP_BAN,
-  CMD_JAIL_IP_RELEASE,
-  CMD_JAIL_FILTER_STATS,
-  CMD_JAIL_FILTER_RELOAD,
-  CMD_MAX_NUMBER,
+  CMD_NONE = 0,  /**< unset */
+  CMD_RESP,      /**< response of command */
+  CMD_HELP,      /**< show help for commands (used internally by client) */
+  CMD_PING = 8,  /**< check connection */
+  CMD_STATUS,    /**< show general status of f2b daemon */
+  CMD_ROTATE,    /**< reopen logfile. works only if set `logdest = file` */
+  CMD_RELOAD,    /**< reload all jails */
+  CMD_SHUTDOWN,  /**< gracefull shutdown */
+  /* jail commands */
+  CMD_JAIL_STATUS = 16,    /**< show status of given jail */
+  CMD_JAIL_SET,            /**< set parameter of given jail */
+  CMD_JAIL_IP_STATUS,      /**< show status of given ip */
+  CMD_JAIL_IP_BAN,         /**< force ban given ip */
+  CMD_JAIL_IP_RELEASE,     /**< force unban given ip */
+  CMD_JAIL_FILTER_STATS,   /**< show stats of fileter matches */
+  CMD_JAIL_FILTER_RELOAD,  /**< reload filter patterns from file */
+  CMD_MAX_NUMBER,          /**< placeholder */
 };
 
+/**
+ * @brief Print to stdout help for defined commands
+ */
 void f2b_cmd_help();
+
+/**
+ * @brief Try to parse user input
+ * @param buf Buffer of control message for storing parsed args
+ * @param bufsize Size of buffer size above
+ * @param src Line with user input
+ * @returns @a CMD_NONE if parsing fails, or cmd type less than @a CMD_MAX_NUMBER on success
+ */
 enum f2b_cmd_type
-f2b_cmd_parse     (char *buf, size_t bufsize, const char *src);
+f2b_cmd_parse(char *buf, size_t bufsize, const char *src);
 
+/**
+ * @brief Append data piece to data buffer of control message
+ * @param buf Buffer of control message for storing parsed args
+ * @param bufsize Size of buffer size above
+ * @param arg Piece to append
+ */
 void
 f2b_cmd_append_arg(char *buf, size_t bufsize, const char *arg);
-
+/**
+ * @brief Checks is args count match given command type
+ * @param type Command type
+ * @param argc Args count
+ * @returns true if matches, false if not
+ */
 bool
 f2b_cmd_check_argc(enum f2b_cmd_type type, int argc);
 
diff --git a/src/common.h b/src/common.h
index ab31f83..72c6da4 100644
--- a/src/common.h
+++ b/src/common.h
@@ -26,19 +26,42 @@
 #include <time.h>
 #include <unistd.h>
 
+/**
+ * @file
+ * This header contains common includes, usefull macro defs and default paths
+ */
+
 #include "strlcpy.h"
 
+/**
+ * @def DEFAULT_PIDFILE_PATH
+ * Self-descriptive
+ */
 #define DEFAULT_PIDFILE_PATH "/var/run/f2b.pid"
+/**
+ * Default path of unix control socket (server endpoint)
+ */
 #define DEFAULT_CSOCKET_PATH "/var/run/f2b.sock"
+/**
+ * Template for making path for client side of connection to control socket
+ */
 #define DEFAULT_CSOCKET_CPATH "/tmp/f2bc-sock-XXXXXX"
 
+/**
+ * @def UNUSED
+ * Supresses compiler warning about unused variable
+ */
 #define UNUSED(x)  (void)(x)
 
+/**
+ * @def SA_REGISTER
+ * Register signal handler
+ */
 #define SA_REGISTER(SIGNUM, HANDLER) \
   memset(&act, 0x0, sizeof(act)); \
   act.sa_handler = HANDLER; \
   if (sigaction(SIGNUM, &act, NULL) != 0) { \
-    f2b_log_msg(log_error, "can't register handler for " #SIGNUM); \
+    f2b_log_msg(log_fatal, "can't register handler for " #SIGNUM); \
     return EXIT_FAILURE; \
   }