Filter: Implement for loops (cf3e0a5f) · Commits · 戴 / Bird

doc/bird.sgml

+20 −6

Original line number	Diff line number	Diff line
		@@ -1668,7 +1668,8 @@ prefix and an ASN as arguments.
		<sect>Control structures
		<label id="control-structures">

		<p>Filters support two control structures: conditions and case switches.
		<p>Filters support several control structures: conditions, for loops and case
		switches.

		<p>Syntax of a condition is: <cf>if <M>boolean expression</M> then <m/commandT/;
		else <m/commandF/;</cf> and you can use <cf>{ <m/command1/; <m/command2/;
		@@ -1676,6 +1677,14 @@ else <m/commandF/;</cf> and you can use <cf>{ <m/command1/; <m/command2/;
		omitted. If the <cf><m>boolean expression</m></cf> is true, <m/commandT/ is
		executed, otherwise <m/commandF/ is executed.

		<p>For loops allow to iterate over elements in compound data like BGP paths or
		community lists. The syntax is: <cf>for [ <m/type/ ] <m/variable/ in <m/expr/
		do <m/command/;</cf> and you can also use compound command like in conditions.
		The expression is evaluated to a compound data, then for each element from such
		data the command is executed with the item assigned to the variable. A variable
		may be an existing one (when just name is used) or a locally defined (when type
		and name is used). In both cases, it must have the same type as elements.

		<p>The <cf>case</cf> is similar to case from Pascal. Syntax is <cf>case
		<m/expr/ { else: \| <m/num_or_prefix [ .. num_or_prefix]/: <m/statement/ ; [
		... ] }</cf>. The expression after <cf>case</cf> can be of any type which can be
		@@ -1688,16 +1697,21 @@ neither of the <cf/:/ clauses, the statements after <cf/else:/ are executed.
		<p>Here is example that uses <cf/if/ and <cf/case/ structures:

		<code>
		if 1234 = i then printn "."; else {
		print "not 1234";
		print "You need {} around multiple commands";
		}

		for int asn in bgp_path do {
		printn "ASN: ", asn;
		if asn < 65536 then print " (2B)"; else print " (4B)";
		}

		case arg1 {
		2: print "two"; print "I can do more commands without {}";
		3 .. 5: print "three to five";
		else: print "something else";
		}

		if 1234 = i then printn "."; else {
		print "not 1234";
		print "You need {} around multiple commands";
		}
		</code>

filter/config.Y

+20 −1

Original line number	Diff line number	Diff line
		@@ -307,6 +307,7 @@ CF_KEYWORDS(FUNCTION, PRINT, PRINTN, UNSET, RETURN,
		INT, BOOL, IP, TYPE, PREFIX, RD, PAIR, QUAD, EC, LC,
		SET, STRING, BGPMASK, BGPPATH, CLIST, ECLIST, LCLIST,
		IF, THEN, ELSE, CASE,
		FOR, IN, DO,
		TRUE, FALSE, RT, RO, UNKNOWN, GENERIC,
		FROM, GW, NET, MASK, PROTO, SOURCE, SCOPE, DEST, IFNAME, IFINDEX, WEIGHT, GW_MPLS,
		PREFERENCE,
		@@ -342,6 +343,7 @@ CF_KEYWORDS(FUNCTION, PRINT, PRINTN, UNSET, RETURN,
		%type <v> set_atom switch_atom fipa
		%type <px> fprefix
		%type <t> get_cf_position
		%type <s> for_var

		CF_GRAMMAR

		@@ -899,6 +901,11 @@ var:
		$$ = f_new_inst(FI_VAR_INIT, $3, sym);
		}

		for_var:
		type symbol { $$ = cf_define_symbol($2, SYM_VARIABLE \| $1, offset, f_new_var(sym_->scope)); }
		\| CF_SYM_KNOWN { $$ = $1; cf_assert_symbol($1, SYM_VARIABLE); }
		;

		cmd:
		'{' cmds_scoped '}' {
		$$ = $2;
		@@ -909,6 +916,18 @@ cmd:
		\| IF term THEN cmd ELSE cmd {
		$$ = f_new_inst(FI_CONDITION, $2, $4, $6);
		}
		\| FOR {
		/* Reserve space for walk data on stack */
		cf_push_scope(NULL);
		conf_this_scope->slots += 2;
		} for_var IN
		/* Parse term in the parent scope */
		{ conf_this_scope->active = 0; } term { conf_this_scope->active = 1; }
		DO cmd {
		cf_pop_scope();
		$$ = f_new_inst(FI_FOR_INIT, $6, $3);
		$$->next = f_new_inst(FI_FOR_NEXT, $3, $9);
		}
		\| CF_SYM_KNOWN '=' term ';' {
		switch ($1->class) {
		case SYM_VARIABLE_RANGE:

filter/data.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -72,6 +72,7 @@ enum f_type
		f_type_element_type(enum f_type t)
		{
		switch(t) {
		case T_PATH: return T_INT;
		case T_CLIST: return T_PAIR;
		case T_ECLIST: return T_EC;
		case T_LCLIST: return T_LC;

filter/f-inst.c

+93 −0

Original line number	Diff line number	Diff line
		@@ -87,6 +87,11 @@
		* m4_dnl RESULT_VOID; return undef
		* m4_dnl }
		*
		* Note that runtime arguments m4_dnl (ARG*, VARARG) must be defined before
		* parse-time arguments m4_dnl (LINE, SYMBOL, ...). During linearization,
		* first ones move position in f_line by linearizing arguments first, while
		* second ones store data to the current position.
		*
		* Also note that the { ... } blocks are not respected by M4 at all.
		* If you get weird unmatched-brace-pair errors, check what it generated and why.
		* What is really considered as one instruction is not the { ... } block
		@@ -543,6 +548,94 @@
		RESULT_VAL(val);
		}

		INST(FI_FOR_INIT, 1, 0) {
		NEVER_CONSTANT;
		ARG_ANY(1);
		SYMBOL;

		FID_NEW_BODY()
		ASSERT((sym->class & ~0xff) == SYM_VARIABLE);

		/* Static type check */
		if (f1->type)
		{
		enum f_type t_var = (sym->class & 0xff);
		enum f_type t_arg = f_type_element_type(f1->type);
		if (!t_arg)
		cf_error("Value of expression in FOR must be iterable, got %s",
		f_type_name(f1->type));
		if (t_var != t_arg)
		cf_error("Loop variable '%s' in FOR must be %s, is %s",
		sym->name, f_type_name(t_arg), f_type_name(t_var));
		}

		FID_INTERPRET_BODY()

		/* Dynamic type check */
		if ((sym->class & 0xff) != f_type_element_type(v1.type))
		runtime("Mismatched argument and variable type");

		/* Setup the index */
		v2 = (struct f_val) { .type = T_INT, .val.i = 0 };

		/* Keep v1 and v2 on the stack */
		fstk->vcnt += 2;
		}

		INST(FI_FOR_NEXT, 2, 0) {
		NEVER_CONSTANT;
		SYMBOL;

		/* Type checks are done in FI_FOR_INIT */

		/* Loop variable */
		struct f_val *var = &fstk->vstk[curline.vbase + sym->offset];
		int step = 0;

		switch(v1.type)
		{
		case T_PATH:
		var->type = T_INT;
		step = as_path_walk(v1.val.ad, &v2.val.i, &var->val.i);
		break;

		case T_CLIST:
		var->type = T_PAIR;
		step = int_set_walk(v1.val.ad, &v2.val.i, &var->val.i);
		break;

		case T_ECLIST:
		var->type = T_EC;
		step = ec_set_walk(v1.val.ad, &v2.val.i, &var->val.ec);
		break;

		case T_LCLIST:
		var->type = T_LC;
		step = lc_set_walk(v1.val.ad, &v2.val.i, &var->val.lc);
		break;

		default:
		runtime( "Clist or lclist expected" );
		}

		if (step)
		{
		/* Keep v1 and v2 on the stack */
		fstk->vcnt += 2;

		/* Repeat this instruction */
		curline.pos--;

		/* Execute the loop body */
		LINE(1, 0);

		/* Space for loop variable, may be unused */
		fstk->vcnt += 1;
		}
		else
		var->type = T_VOID;
		}

		INST(FI_CONDITION, 1, 0) {
		ARG(1, T_BOOL);
		if (v1.val.i)

filter/test.conf

+39 −1

Original line number	Diff line number	Diff line
		@@ -758,6 +758,15 @@ int set set12;
		bt_assert(delete(p2, [4..5]) = prepend(prepend(prepend(prepend(+empty+, 3), 3), 2), 1));

		bt_assert(format([= 1 2+ 3 =]) = "[= 1 2 + 3 =]");

		# iteration over path
		int x = 0;
		int y = 0;
		for int i in p2 do {
		x = x + i;
		y = y + x;
		}
		bt_assert(x = 18 && y = 50);
		}

		bt_test_suite(t_path, "Testing paths");
		@@ -884,6 +893,12 @@ clist r;
		bt_assert(format(r) = "(clist (2,1) (1,3) (2,2) (3,1) (2,3))");
		bt_assert(r.min = (1,3));
		bt_assert(r.max = (3,1));

		# iteration over clist
		int x = 0;
		for pair c in r do
		x = x + c.asn * c.asn * c.data;
		bt_assert(x = 36);
		}

		bt_test_suite(t_clist, "Testing lists of communities");
		@@ -999,6 +1014,13 @@ eclist r;
		bt_assert(format(r) = "(eclist (rt, 2, 1) (rt, 1, 3) (rt, 2, 2) (rt, 3, 1) (rt, 2, 3))");
		bt_assert(r.min = (rt, 1, 3));
		bt_assert(r.max = (rt, 3, 1));

		# iteration over eclist
		int x = 0;
		for ec c in r do
		if c > (rt, 2, 0) && c < (rt, 3, 0) then
		x = x + 1;
		bt_assert(x = 3);
		}

		bt_test_suite(t_eclist, "Testing lists of extended communities");
		@@ -1117,6 +1139,19 @@ lclist r;
		bt_assert(format(r) = "(lclist (2, 3, 3) (1, 2, 3) (2, 3, 1) (3, 1, 2) (2, 1, 3))");
		bt_assert(r.min = (1, 2, 3));
		bt_assert(r.max = (3, 1, 2));

		# iteration over lclist
		int x = 0;
		int y = 0;
		lc mx = (0, 0, 0);
		for lc c in r do {
		int asn2 = c.asn * c.asn;
		x = x + asn2 * c.data1;
		y = y + asn2 * c.data2;
		if c > mx then mx = c;
		}
		bt_assert(x = 39 && y = 49);
		bt_assert(mx = r.max);
		}

		bt_test_suite(t_lclist, "Testing lists of large communities");
		@@ -1580,13 +1615,16 @@ filter vpn_filter
		bt_assert(net.type != NET_IP6);
		bt_assert(net.rd = 0:1:2);

		bool b = false;
		case (net.type) {
		NET_IP4: print "IPV4";
		NET_IP6: print "IPV6";
		else: b = true;
		}
		bt_assert(b);

		bt_check_assign(from, 10.20.30.40);
		bt_check_assign(gw, 55.55.55.44);
		# bt_check_assign(gw, 55.55.55.44);

		bgp_community.add((3,5));
		bgp_ext_community.add((ro, 135, 999));

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