Merge remote-tracking branch 'origin/mq-filter-stack'

5 files changed, 232 insertions, 118 deletions

diff --git a/conf/Makefile b/conf/Makefile
index 5c10bbcb..19db9c2c 100644
--- a/conf/Makefile
+++ b/conf/Makefile
@@ -10,12 +10,12 @@ BISON_DEBUG=-t
 #FLEX_DEBUG=-d
 endif
 
-$(conf-y-targets): $(s)confbase.Y $(s)flowspec.Y
-	$(M4) $(M4FLAGS) -P $| $^ >$@
+$(o)cf-parse.y: $(s)gen_parser.m4
+$(o)keywords.h: $(s)gen_keywords.m4
+$(o)commands.h: $(s)gen_commands.m4
 
-$(o)cf-parse.y: | $(s)gen_parser.m4
-$(o)keywords.h: | $(s)gen_keywords.m4
-$(o)commands.h: | $(s)gen_commands.m4 $(srcdir)/client/cmds.m4
+$(conf-y-targets): $(s)confbase.Y $(s)flowspec.Y
+	$(M4) $(M4FLAGS) -P $(if $(word 2,$(filter %.m4,$^)),$(error "Too many M4 scripts for one target"),$(filter %.m4,$^)) $(filter %.Y,$^) >$@
 
 $(o)cf-parse.tab.h: $(o)cf-parse.tab.c
 
diff --git a/conf/cf-lex.l b/conf/cf-lex.l
index 63c76940..1d6cae2c 100644
--- a/conf/cf-lex.l
+++ b/conf/cf-lex.l
@@ -45,6 +45,7 @@
 #include "nest/route.h"
 #include "nest/protocol.h"
 #include "filter/filter.h"
+#include "filter/f-inst.h"
 #include "conf/conf.h"
 #include "conf/cf-parse.tab.h"
 #include "lib/string.h"
@@ -64,7 +65,7 @@ struct keyword {
 #endif
 
 
-static uint cf_hash(byte *c);
+static uint cf_hash(const byte *c);
 
 #define KW_KEY(n)		n->name
 #define KW_NEXT(n)		n->next
@@ -95,6 +96,15 @@ int (*cf_read_hook)(byte *buf, unsigned int max, int fd);
 struct include_file_stack *ifs;
 static struct include_file_stack *ifs_head;
 
+#define QUOTED_BUFFER_SIZE  4096
+static BUFFER_(char) quoted_buffer;
+static char quoted_buffer_data[QUOTED_BUFFER_SIZE];
+static inline void quoted_buffer_init(void) {
+  quoted_buffer.used = 0;
+  quoted_buffer.size = QUOTED_BUFFER_SIZE;
+  quoted_buffer.data = quoted_buffer_data;
+}
+
 #define MAX_INCLUDE_DEPTH 8
 
 #define YY_INPUT(buf,result,max) result = cf_read_hook(buf, max, ifs->fd);
@@ -105,6 +115,8 @@ static struct include_file_stack *ifs_head;
 static void cf_include(char *arg, int alen);
 static int check_eof(void);
 
+static enum yytokentype cf_lex_symbol(const char *data);
+
 %}
 
 %option noyywrap
@@ -112,24 +124,26 @@ static int check_eof(void);
 %option nounput
 %option noreject
 
-%x COMMENT CCOMM CLI
+%x COMMENT CCOMM CLI QUOTED APOSTROPHED INCLUDE
 
 ALPHA [a-zA-Z_]
 DIGIT [0-9]
 XIGIT [0-9a-fA-F]
 ALNUM [a-zA-Z_0-9]
 WHITE [ \t]
-include   ^{WHITE}*include{WHITE}*\".*\"{WHITE}*;
 
 %%
-{include} {
-  char *start, *end;
-
+^{WHITE}*include{WHITE}*\" {
   if (!ifs->depth)
     cf_error("Include not allowed in CLI");
 
-  start = strchr(yytext, '"');
-  start++;
+  BEGIN(INCLUDE);
+}
+
+<INCLUDE>[^"\n]+["]{WHITE}*; {
+  char *start, *end;
+
+  start = yytext;
 
   end = strchr(start, '"');
   *end = 0;
@@ -138,15 +152,23 @@ include   ^{WHITE}*include{WHITE}*\".*\"{WHITE}*;
     cf_error("Include with empty argument");
 
   cf_include(start, end-start);
+
+  BEGIN(INITIAL);
 }
 
+<INCLUDE>["]	        cf_error("Include with empty argument");
+<INCLUDE>.		cf_error("Unterminated include");
+<INCLUDE>\n		cf_error("Unterminated include");
+<INCLUDE><<EOF>>	cf_error("Unterminated include");
+
+
 {DIGIT}+:{DIGIT}+ {
   uint len1 UNUSED, len2;
   u64 l;
   char *e;
 
   errno = 0;
-  l = strtoul(yytext, &e, 10);
+  l = bstrtoul10(yytext, &e);
   if (e && (*e != ':') || (errno == ERANGE) || (l >> 32))
     cf_error("ASN out of range");
 
@@ -164,7 +186,7 @@ include   ^{WHITE}*include{WHITE}*\".*\"{WHITE}*;
   }
 
   errno = 0;
-  l = strtoul(e+1, &e, 10);
+  l = bstrtoul10(e+1, &e);
   if (e && *e || (errno == ERANGE) || (l >> len2))
     cf_error("Number out of range");
   cf_lval.i64 |= l;
@@ -191,13 +213,13 @@ include   ^{WHITE}*include{WHITE}*\".*\"{WHITE}*;
   }
 
   errno = 0;
-  l = strtoul(yytext+2, &e, 10);
+  l = bstrtoul10(yytext+2, &e);
   if (e && (*e != ':') || (errno == ERANGE) || (l >> len1))
     cf_error("ASN out of range");
   cf_lval.i64 |= ((u64) l) << len2;
 
   errno = 0;
-  l = strtoul(e+1, &e, 10);
+  l = bstrtoul10(e+1, &e);
   if (e && *e || (errno == ERANGE) || (l >> len2))
     cf_error("Number out of range");
   cf_lval.i64 |= l;
@@ -219,7 +241,7 @@ include   ^{WHITE}*include{WHITE}*\".*\"{WHITE}*;
   cf_lval.i64 |= ((u64) ip4_to_u32(ip4)) << 16;
 
   errno = 0;
-  l = strtoul(e, &e, 10);
+  l = bstrtoul10(e, &e);
   if (e && *e || (errno == ERANGE) || (l >> 16))
     cf_error("Number out of range");
   cf_lval.i64 |= l;
@@ -243,7 +265,7 @@ include   ^{WHITE}*include{WHITE}*\".*\"{WHITE}*;
   char *e;
   unsigned long int l;
   errno = 0;
-  l = strtoul(yytext+2, &e, 16);
+  l = bstrtoul16(yytext+2, &e);
   if (e && *e || errno == ERANGE || (unsigned long int)(unsigned int) l != l)
     cf_error("Number out of range");
   cf_lval.i = l;
@@ -254,7 +276,7 @@ include   ^{WHITE}*include{WHITE}*\".*\"{WHITE}*;
   char *e;
   unsigned long int l;
   errno = 0;
-  l = strtoul(yytext, &e, 10);
+  l = bstrtoul10(yytext, &e);
   if (e && *e || errno == ERANGE || (unsigned long int)(unsigned int) l != l)
     cf_error("Number out of range");
   cf_lval.i = l;
@@ -266,26 +288,23 @@ else: {
   return ELSECOL;
 }
 
-({ALPHA}{ALNUM}*|[']({ALNUM}|[-]|[\.]|[:])*[']) {
-  if(*yytext == '\'') {
-    yytext[yyleng-1] = 0;
-    yytext++;
-  }
+['] {
+  BEGIN(APOSTROPHED);
+  quoted_buffer_init();
+}
 
-  struct keyword *k = HASH_FIND(kw_hash, KW, yytext);
-  if (k)
-  {
-    if (k->value > 0)
-      return k->value;
-    else
-    {
-      cf_lval.i = -k->value;
-      return ENUM;
-    }
-  }
+<APOSTROPHED>{ALNUM}|[-]|[.:]	BUFFER_PUSH(quoted_buffer) = yytext[0];
+<APOSTROPHED>\n			cf_error("Unterminated symbol");
+<APOSTROPHED><<EOF>>		cf_error("Unterminated symbol");
+<APOSTROPHED>['] {
+  BEGIN(INITIAL);
+  BUFFER_PUSH(quoted_buffer) = 0;
+  return cf_lex_symbol(quoted_buffer_data);
+}
+<APOSTROPHED>.			cf_error("Invalid character in apostrophed symbol");
 
-  cf_lval.s = cf_get_symbol(yytext);
-  return SYM;
+({ALPHA}{ALNUM}*) {
+  return cf_lex_symbol(yytext);
 }
 
 <CLI>(.|\n) {
@@ -301,14 +320,21 @@ else: {
   return yytext[0];
 }
 
-["][^"\n]*["] {
-  yytext[yyleng-1] = 0;
-  cf_lval.t = cfg_strdup(yytext+1);
-  yytext[yyleng-1] = '"';
+["] {
+  BEGIN(QUOTED);
+  quoted_buffer_init();
+}
+
+<QUOTED>\n	cf_error("Unterminated string");
+<QUOTED><<EOF>> cf_error("Unterminated string");
+<QUOTED>["]	{
+  BEGIN(INITIAL);
+  BUFFER_PUSH(quoted_buffer) = 0;
+  cf_lval.t = cfg_strdup(quoted_buffer_data);
   return TEXT;
 }
 
-["][^"\n]*\n	cf_error("Unterminated string");
+<QUOTED>.	BUFFER_PUSH(quoted_buffer) = yytext[0];
 
 <INITIAL,COMMENT><<EOF>>	{ if (check_eof()) return END; }
 
@@ -349,7 +375,7 @@ else: {
 %%
 
 static uint
-cf_hash(byte *c)
+cf_hash(const byte *c)
 {
   uint h = 13 << 24;
 
@@ -358,7 +384,6 @@ cf_hash(byte *c)
   return h;
 }
 
-
 /*
  * IFS stack - it contains structures needed for recursive processing
  * of include in config files. On the top of the stack is a structure
@@ -519,7 +544,7 @@ check_eof(void)
 }
 
 static struct symbol *
-cf_new_symbol(byte *c)
+cf_new_symbol(const byte *c)
 {
   struct symbol *s;
 
@@ -527,11 +552,8 @@ cf_new_symbol(byte *c)
   if (l > SYM_MAX_LEN)
     cf_error("Symbol too long");
 
-  s = cfg_alloc(sizeof(struct symbol) + l);
-  s->scope = conf_this_scope;
-  s->class = SYM_VOID;
-  s->def = NULL;
-  s->aux = 0;
+  s = cfg_allocz(sizeof(struct symbol) + l + 1);
+  *s = (struct symbol) { .scope = conf_this_scope, .class = SYM_VOID, };
   strcpy(s->name, c);
 
   if (!new_config->sym_hash.data)
@@ -539,6 +561,8 @@ cf_new_symbol(byte *c)
 
   HASH_INSERT2(new_config->sym_hash, SYM, new_config->pool, s);
 
+  add_tail(&(new_config->symbols), &(s->n));
+
   return s;
 }
 
@@ -554,7 +578,7 @@ cf_new_symbol(byte *c)
  * signify no match.
  */
 struct symbol *
-cf_find_symbol(struct config *cfg, byte *c)
+cf_find_symbol(const struct config *cfg, const byte *c)
 {
   struct symbol *s;
 
@@ -562,6 +586,7 @@ cf_find_symbol(struct config *cfg, byte *c)
       (s = HASH_FIND(cfg->sym_hash, SYM, c, 1)))
     return s;
 
+  /* In CLI command parsing, fallback points to the current config, otherwise it is NULL. */
   if (cfg->fallback &&
       cfg->fallback->sym_hash.data &&
       (s = HASH_FIND(cfg->fallback->sym_hash, SYM, c, 1)))
@@ -580,11 +605,33 @@ cf_find_symbol(struct config *cfg, byte *c)
  * existing symbol is found.
  */
 struct symbol *
-cf_get_symbol(byte *c)
+cf_get_symbol(const byte *c)
 {
   return cf_find_symbol(new_config, c) ?: cf_new_symbol(c);
 }
 
+/**
+ * cf_localize_symbol - get the local instance of given symbol
+ * @sym: the symbol to localize
+ *
+ * This functions finds the symbol that is local to current scope
+ * for purposes of cf_define_symbol().
+ */
+struct symbol *
+cf_localize_symbol(struct symbol *sym)
+{
+  /* If the symbol type is void, it has been recently allocated just in this scope. */
+  if (!sym->class)
+    return sym;
+  
+  /* If the scope is the current, it is already defined in this scope. */
+  if (sym->scope == conf_this_scope)
+    cf_error("Symbol already defined");
+
+  /* Not allocated here yet, doing it now. */
+  return cf_new_symbol(sym->name);
+}
+
 struct symbol *
 cf_default_name(char *template, int *counter)
 {
@@ -604,33 +651,32 @@ cf_default_name(char *template, int *counter)
   cf_error("Unable to generate default name");
 }
 
-/**
- * cf_define_symbol - define meaning of a symbol
- * @sym: symbol to be defined
- * @type: symbol class to assign
- * @def: class dependent data
- *
- * Defines new meaning of a symbol. If the symbol is an undefined
- * one (%SYM_VOID), it's just re-defined to the new type. If it's defined
- * in different scope, a new symbol in current scope is created and the
- * meaning is assigned to it. If it's already defined in the current scope,
- * an error is reported via cf_error().
- *
- * Result: Pointer to the newly defined symbol. If we are in the top-level
- * scope, it's the same @sym as passed to the function.
- */
-struct symbol *
-cf_define_symbol(struct symbol *sym, int type, void *def)
+static enum yytokentype
+cf_lex_symbol(const char *data)
 {
-  if (sym->class)
+  /* Have we defined such a symbol? */
+  struct symbol *sym = cf_get_symbol(data);
+  cf_lval.s = sym;
+
+  if (sym->class != SYM_VOID)
+    return CF_SYM_KNOWN;
+
+  /* Is it a keyword? */
+  struct keyword *k = HASH_FIND(kw_hash, KW, data);
+  if (k)
+  {
+    if (k->value > 0)
+      return k->value;
+    else
     {
-      if (sym->scope == conf_this_scope)
-	cf_error("Symbol already defined");
-      sym = cf_new_symbol(sym->name);
+      cf_lval.i = -k->value;
+      return ENUM;
     }
-  sym->class = type;
-  sym->def = def;
-  return sym;
+  }
+
+  /* OK, undefined symbol */
+  cf_lval.s = sym;
+  return CF_SYM_UNDEFINED;
 }
 
 static void
@@ -697,6 +743,7 @@ cf_push_scope(struct symbol *sym)
   conf_this_scope = s;
   s->active = 1;
   s->name = sym;
+  s->slots = 0;
 }
 
 /**
@@ -711,6 +758,7 @@ cf_pop_scope(void)
 {
   conf_this_scope->active = 0;
   conf_this_scope = conf_this_scope->next;
+
   ASSERT(conf_this_scope);
 }
 
@@ -724,9 +772,6 @@ cf_pop_scope(void)
 char *
 cf_symbol_class_name(struct symbol *sym)
 {
-  if (cf_symbol_is_constant(sym))
-    return "constant";
-
   switch (sym->class)
     {
     case SYM_VOID:
@@ -741,6 +786,12 @@ cf_symbol_class_name(struct symbol *sym)
       return "filter";
     case SYM_TABLE:
       return "routing table";
+    case SYM_ATTRIBUTE:
+      return "custom attribute";
+    case SYM_CONSTANT_RANGE:
+      return "constant";
+    case SYM_VARIABLE_RANGE:
+      return "variable";
     default:
       return "unknown type";
     }
diff --git a/conf/conf.c b/conf/conf.c
index 0b797dec..b21d5213 100644
--- a/conf/conf.c
+++ b/conf/conf.c
@@ -98,6 +98,7 @@ config_alloc(const char *name)
   memcpy(ndup, name, nlen);
 
   init_list(&c->tests);
+  init_list(&c->symbols);
   c->mrtdump_file = -1; /* Hack, this should be sysdep-specific */
   c->pool = p;
   c->mem = l;
@@ -258,6 +259,8 @@ config_do_commit(struct config *c, int type)
   if (old_config)
     old_config->obstacle_count++;
 
+  DBG("filter_commit\n");
+  filter_commit(c, old_config);
   DBG("sysdep_commit\n");
   int force_restart = sysdep_commit(c, old_config);
   DBG("global_commit\n");
diff --git a/conf/conf.h b/conf/conf.h
index 777a1fca..21dc3fa1 100644
--- a/conf/conf.h
+++ b/conf/conf.h
@@ -24,6 +24,7 @@ struct config {
   list tables;				/* Configured routing tables (struct rtable_config) */
   list logfiles;			/* Configured log files (sysdep) */
   list tests;				/* Configured unit tests (f_bt_test_suite) */
+  list symbols;				/* Configured symbols in config order */
 
   int mrtdump_file;			/* Configured MRTDump file (sysdep, fd in unix) */
   char *syslog_name;			/* Name used for syslog (NULL -> no syslog) */
@@ -107,18 +108,29 @@ void cfg_copy_list(list *dest, list *src, unsigned node_size);
 extern int (*cf_read_hook)(byte *buf, uint max, int fd);
 
 struct symbol {
+  node n;				/* In list of symbols in config */
   struct symbol *next;
   struct sym_scope *scope;
-  int class;
-  int aux;
-  void *aux2;
-  void *def;
-  char name[1];
+  int class;				/* SYM_* */
+  uint flags;				/* SYM_FLAG_* */
+
+  union {
+    struct proto_config *proto;		/* For SYM_PROTO and SYM_TEMPLATE */
+    const struct f_line *function;	/* For SYM_FUNCTION */
+    const struct filter *filter;	/* For SYM_FILTER */
+    struct rtable_config *table;	/* For SYM_TABLE */
+    struct f_dynamic_attr *attribute;	/* For SYM_ATTRIBUTE */
+    struct f_val *val;			/* For SYM_CONSTANT */
+    uint offset;			/* For SYM_VARIABLE */
+  };
+
+  char name[0];
 };
 
 struct sym_scope {
   struct sym_scope *next;		/* Next on scope stack */
   struct symbol *name;			/* Name of this scope */
+  uint slots;				/* Variable slots */
   int active;				/* Currently entered */
 };
 
@@ -138,8 +150,11 @@ struct sym_scope {
 #define SYM_CONSTANT 0x200	/* 0x200-0x2ff are variable types */
 #define SYM_CONSTANT_RANGE SYM_CONSTANT ... (SYM_CONSTANT | 0xff)
 
-#define SYM_TYPE(s) (((struct f_val *) (s)->def)->type)
-#define SYM_VAL(s) (((struct f_val *) (s)->def)->val)
+#define SYM_TYPE(s) ((s)->val->type)
+#define SYM_VAL(s) ((s)->val->val)
+
+/* Symbol flags */
+#define SYM_FLAG_SAME 0x1	/* For SYM_FUNCTION and SYM_FILTER */
 
 struct include_file_stack {
   void *buffer;				/* Internal lexer state */
@@ -162,19 +177,37 @@ int cf_lex(void);
 void cf_lex_init(int is_cli, struct config *c);
 void cf_lex_unwind(void);
 
-struct symbol *cf_find_symbol(struct config *cfg, byte *c);
+struct symbol *cf_find_symbol(const struct config *cfg, const byte *c);
 
-struct symbol *cf_get_symbol(byte *c);
+struct symbol *cf_get_symbol(const byte *c);
 struct symbol *cf_default_name(char *template, int *counter);
-struct symbol *cf_define_symbol(struct symbol *symbol, int type, void *def);
+struct symbol *cf_localize_symbol(struct symbol *sym);
+
+/**
+ * cf_define_symbol - define meaning of a symbol
+ * @sym: symbol to be defined
+ * @type: symbol class to assign
+ * @def: class dependent data
+ *
+ * Defines new meaning of a symbol. If the symbol is an undefined
+ * one (%SYM_VOID), it's just re-defined to the new type. If it's defined
+ * in different scope, a new symbol in current scope is created and the
+ * meaning is assigned to it. If it's already defined in the current scope,
+ * an error is reported via cf_error().
+ *
+ * Result: Pointer to the newly defined symbol. If we are in the top-level
+ * scope, it's the same @sym as passed to the function.
+ */
+#define cf_define_symbol(sym_, type_, var_, def_) ({ \
+    struct symbol *sym = cf_localize_symbol(sym_); \
+    sym->class = type_; \
+    sym->var_ = def_; \
+    sym; })
+
 void cf_push_scope(struct symbol *);
 void cf_pop_scope(void);
 char *cf_symbol_class_name(struct symbol *sym);
 
-static inline int cf_symbol_is_constant(struct symbol *sym)
-{ return (sym->class & 0xff00) == SYM_CONSTANT; }
-
-
 /* Parser */
 
 extern char *cf_text;
diff --git a/conf/confbase.Y b/conf/confbase.Y
index 3fd034db..775af22d 100644
--- a/conf/confbase.Y
+++ b/conf/confbase.Y
@@ -33,6 +33,21 @@ check_u16(uint val)
     cf_error("Value %u out of range (0-65535)", val);
 }
 
+#define cf_assert(cond, ...) do { if (!(cond)) cf_error(__VA_ARGS__); } while (0)
+static inline void cf_assert_symbol(const struct symbol *sym, uint class) {
+  switch (class) {
+    case SYM_PROTO: cf_assert(sym->class == SYM_PROTO, "Protocol name required"); break;
+    case SYM_TEMPLATE: cf_assert(sym->class == SYM_TEMPLATE, "Protocol template name required"); break;
+    case SYM_FUNCTION: cf_assert(sym->class == SYM_FUNCTION, "Function name required"); break;
+    case SYM_FILTER: cf_assert(sym->class == SYM_FILTER, "Filter name required"); break;
+    case SYM_TABLE: cf_assert(sym->class == SYM_TABLE, "Table name required"); break;
+    case SYM_ATTRIBUTE: cf_assert(sym->class == SYM_ATTRIBUTE, "Custom attribute name required"); break;
+    case SYM_VARIABLE: cf_assert((sym->class & ~0xff) == SYM_VARIABLE, "Variable name required"); break;
+    case SYM_CONSTANT: cf_assert((sym->class & ~0xff) == SYM_CONSTANT, "Constant name required"); break;
+    default: bug("This shall not happen");
+  }
+}
+
 CF_DECLS
 
 %union {
@@ -49,13 +64,19 @@ CF_DECLS
   struct rtable_config *r;
   struct channel_config *cc;
   struct f_inst *x;
+  struct {
+    struct f_inst *begin, *end;
+  } xp;
+  enum filter_return fret;
+  enum ec_subtype ecs;
   struct f_dynamic_attr fda;
   struct f_static_attr fsa;
-  struct filter *f;
+  struct f_lval flv;
+  struct f_line *fl;
+  const struct filter *f;
   struct f_tree *e;
   struct f_trie *trie;
   struct f_val v;
-  struct f_path_mask *h;
   struct password_item *p;
   struct rt_show_data *ra;
   struct sym_show_data *sd;
@@ -78,7 +99,7 @@ CF_DECLS
 %token <ip4> IP4
 %token <ip6> IP6
 %token <i64> VPN_RD
-%token <s> SYM
+%token <s> CF_SYM_KNOWN CF_SYM_UNDEFINED
 %token <t> TEXT
 %type <iface> ipa_scope
 
@@ -88,8 +109,10 @@ CF_DECLS
 %type <net> net_ip4_ net_ip6_ net_ip6 net_ip_ net_ip net_or_ipa
 %type <net_ptr> net_ net_any net_vpn4_ net_vpn6_ net_vpn_ net_roa4_ net_roa6_ net_roa_ net_ip6_sadr_ net_mpls_
 %type <mls> label_stack_start label_stack
+%type <s> CF_SYM_VOID
 
 %type <t> text opttext
+%type <s> symbol
 
 %nonassoc PREFIX_DUMMY
 %left AND OR
@@ -99,6 +122,8 @@ CF_DECLS
 %left '!'
 %nonassoc '.'
 
+%start config
+
 CF_KEYWORDS(DEFINE, ON, OFF, YES, NO, S, MS, US, PORT, VPN, MPLS, FROM)
 
 CF_GRAMMAR
@@ -122,29 +147,31 @@ conf: ';' ;
 conf: definition ;
 
 definition:
-   DEFINE SYM '=' term ';' {
+   DEFINE CF_SYM_VOID '=' term ';' {
      struct f_val *val = cfg_alloc(sizeof(struct f_val));
-     *val = f_eval($4, cfg_mem);
-     if (val->type == T_RETURN) cf_error("Runtime error");
-     cf_define_symbol($2, SYM_CONSTANT | val->type, val);
+     if (f_eval(f_linearize($4), cfg_mem, val) > F_RETURN) cf_error("Runtime error");
+     cf_define_symbol($2, SYM_CONSTANT | val->type, val, val);
    }
  ;
 
 expr:
    NUM
- | '(' term ')' { $$ = f_eval_int($2); }
- | SYM {
-     if ($1->class != (SYM_CONSTANT | T_INT)) cf_error("Number expected");
+ | '(' term ')' { $$ = f_eval_int(f_linearize($2)); }
+ | CF_SYM_KNOWN {
+     if ($1->class != (SYM_CONSTANT | T_INT)) cf_error("Number constant expected");
      $$ = SYM_VAL($1).i; }
  ;
 
-
 expr_us:
    expr S  { $$ = $1 S_; }
  | expr MS { $$ = $1 MS_; }
  | expr US { $$ = $1 US_; }
  ;
 
+CF_SYM_VOID: CF_SYM_UNDEFINED ;
+
+symbol: CF_SYM_VOID | CF_SYM_KNOWN ;
+
 /* Switches */
 
 bool:
@@ -162,15 +189,15 @@ bool:
 ipa:
    IP4 { $$ = ipa_from_ip4($1); }
  | IP6 { $$ = ipa_from_ip6($1); }
- | SYM {
-     if ($1->class != (SYM_CONSTANT | T_IP)) cf_error("IP address expected");
+ | CF_SYM_KNOWN {
+     if ($1->class != (SYM_CONSTANT | T_IP)) cf_error("IP address constant expected");
      $$ = SYM_VAL($1).ip;
    }
  ;
 
 ipa_scope:
    /* empty */ { $$ = NULL; }
- | '%' SYM { $$ = if_get_by_name($2->name); }
+ | '%' symbol { $$ = if_get_by_name($2->name); }
  ;
 
 
@@ -277,27 +304,27 @@ net_:
 
 net_ip6:
    net_ip6_
- | SYM {
+ | CF_SYM_KNOWN {
      if (($1->class != (SYM_CONSTANT | T_NET)) || (SYM_VAL($1).net->type != NET_IP6))
-       cf_error("IPv6 network expected");
+       cf_error("IPv6 network constant expected");
      $$ = * SYM_VAL($1).net;
    }
  ;
 
 net_ip:
    net_ip_
- | SYM {
+ | CF_SYM_KNOWN {
      if (($1->class != (SYM_CONSTANT | T_NET)) || !net_is_ip(SYM_VAL($1).net))
-       cf_error("IP network expected");
+       cf_error("IP network constant expected");
      $$ = * SYM_VAL($1).net;
    }
  ;
 
 net_any:
    net_
- | SYM {
+ | CF_SYM_KNOWN {
      if ($1->class != (SYM_CONSTANT | T_NET))
-       cf_error("Network expected");
+       cf_error("Network constant expected");
      $$ = (net_addr *) SYM_VAL($1).net; /* Avoid const warning */
    }
  ;
@@ -307,13 +334,13 @@ net_or_ipa:
  | net_ip6_
  | IP4 { net_fill_ip4(&($$), $1, IP4_MAX_PREFIX_LENGTH); }
  | IP6 { net_fill_ip6(&($$), $1, IP6_MAX_PREFIX_LENGTH); }
- | SYM {
+ | CF_SYM_KNOWN {
      if ($1->class == (SYM_CONSTANT | T_IP))
        net_fill_ip_host(&($$), SYM_VAL($1).ip);
      else if (($1->class == (SYM_CONSTANT | T_NET)) && net_is_ip(SYM_VAL($1).net))
        $$ = * SYM_VAL($1).net;
      else
-       cf_error("IP address or network expected");
+       cf_error("IP address or network constant expected");
    }
  ;
 
@@ -344,8 +371,8 @@ time:
 
 text:
    TEXT
- | SYM {
-     if ($1->class != (SYM_CONSTANT | T_STRING)) cf_error("String expected");
+ | CF_SYM_KNOWN {
+     if ($1->class != (SYM_CONSTANT | T_STRING)) cf_error("String constant expected");
      $$ = SYM_VAL($1).s;
    }
  ;