raw sockets: config file support

Raw socket usage for udp ipv4 send, can now be turned on/off/auto
from the config file, via udp4_raw.
The mtu used can be set via udp4_raw_mtu.

cfg.lex

@@ -213,6 +213,8 @@ ADD_LOCAL_RPORT		"add_local_rport"
 FORCE_TCP_ALIAS		"force_tcp_alias"|"add_tcp_alias"
 UDP_MTU		"udp_mtu"
 UDP_MTU_TRY_PROTO	"udp_mtu_try_proto"
+UDP4_RAW		"udp4_raw"
+UDP4_RAW_MTU	"udp4_raw_mtu"
 SETFLAG		setflag
 RESETFLAG	resetflag
 ISFLAGSET	isflagset
@@ -607,6 +609,8 @@ SUBST       subst
 <INITIAL>{UDP_MTU}	{ count(); yylval.strval=yytext; return UDP_MTU; }
 <INITIAL>{UDP_MTU_TRY_PROTO}	{ count(); yylval.strval=yytext;
 									return UDP_MTU_TRY_PROTO; }
+<INITIAL>{UDP4_RAW}	{ count(); yylval.strval=yytext; return UDP4_RAW; }
+<INITIAL>{UDP4_RAW_MTU}	{ count(); yylval.strval=yytext; return UDP4_RAW_MTU; }
 <INITIAL>{IF}	{ count(); yylval.strval=yytext; return IF; }
 <INITIAL>{ELSE}	{ count(); yylval.strval=yytext; return ELSE; }
 

cfg.y

@@ -200,6 +200,12 @@
 	#define IF_SCTP(x) warn("sctp support not compiled in")
 #endif
 
+#ifdef USE_RAW_SOCKS
+	#define IF_RAW_SOCKS(x) x
+#else
+	#define IF_RAW_SOCKS(x) warn("raw socket support not compiled in")
+#endif
+
 
 extern int yylex();
 /* safer then using yytext which can be array or pointer */
@@ -323,6 +329,8 @@ extern char *finame;
 %token FORCE_TCP_ALIAS
 %token UDP_MTU
 %token UDP_MTU_TRY_PROTO
+%token UDP4_RAW
+%token UDP4_RAW_MTU
 %token IF
 %token ELSE
 %token SET_ADV_ADDRESS
@@ -1579,6 +1587,12 @@ assign_stm:
 		{ default_core_cfg.udp_mtu_try_proto=$3; fix_global_req_flags(0, 0); }
 	| UDP_MTU_TRY_PROTO EQUAL error
 		{ yyerror("TCP, TLS, SCTP or UDP expected"); }
+	| UDP4_RAW EQUAL intno { IF_RAW_SOCKS(default_core_cfg.udp4_raw=$3); }
+	| UDP4_RAW EQUAL error { yyerror("number expected"); }
+	| UDP4_RAW_MTU EQUAL NUMBER {
+		IF_RAW_SOCKS(default_core_cfg.udp4_raw_mtu=$3);
+	}
+	| UDP4_RAW_MTU EQUAL error { yyerror("number expected"); }
 	| cfg_var
 	| error EQUAL { yyerror("unknown config variable"); }
 	;