Support two representations for embedded IPv4 addresses

DTrace's inet_ntoa6() represents mapped and embedded IPv4 addresses
using the regular IPv4 representation, whereas inet_ntop() uses a
strict IPv6 representation (:: or ::ffff: prefix followed by a regular
IPv4 address).

The implementation uses a 2nd argument to inet_ntoa6() that must be
an integer constant that indicates basic IPv4 representation (0), or
strict IPv4-in-IPv6 representation (non-0).

Signed-off-by: Kris Van Hees <kris.van.hees@oracle.com>
Reviewed-by: Eugene Loh <eugene.loh@oracle.com>

bpf/inet_ntoa6.S

@@ -94,7 +94,7 @@ write_hex16:
 
 /*
  * void inet_ntoa6(const dt_dctx_t *dctx, const uint8_t *src, char *dst,
- *		   uint32 tbloff)
+ *		   uint32 tbloff, int strict)
  */
 	.align	4
 	.global	dt_inet_ntoa6
@@ -121,6 +121,7 @@ dt_inet_ntoa6:
 	add	%r8, OUTPUT_LEN		/* %r8 = converted copy */
 	mov	%r6, %r1		/* %r6 = dctx */
 	stxw	[%fp + -4], %r4		/* store tbloff */
+	stxw	[%fp + -8], %r5		/* store strict */
 
 	mov	%r3, %r2
 	mov	%r2, INPUT_LEN
@@ -198,12 +199,12 @@ dt_inet_ntoa6:
 	and	%r0, 0xf8
 	jne	%r0, 0, .Lnotipv4
 	ldxh	%r0, [%r8 + 10]
-	jeq	%r0, 0xffff, .Lipv4
+	jeq	%r0, 0xffff, .Lipv4_2
 	jne	%r0, 0, .Lnotipv4
 	ldxh	%r0, [%r8 + 12]
-	jne	%r0, 0, .Lipv4
+	jne	%r0, 0, .Lipv4_1
 	ldxh	%r0, [%r8 + 14]
-	jgt	%r0, 1, .Lipv4
+	jgt	%r0, 1, .Lipv4_1
 .Lnotipv4:
 
 	/*
@@ -335,6 +336,28 @@ dt_inet_ntoa6:
 	mov	%r0, 0
 	exit
 
+.Lipv4_1:
+	/* Output IPv4 address prefixed by :: (if strict is set). */
+	ldxw	%r0, [%fp + -8]		/* restore strict */
+	jeq	%r0, 0, .Lipv4
+	stb	[%r9 + 0], ':'
+	stb	[%r9 + 1], ':'
+	add	%r9, 2
+	ja	.Lipv4
+
+.Lipv4_2:
+	/* Output IPv4 address prefixed by ::ffff: (if strict is set). */
+	ldxw	%r0, [%fp + -8]		/* restore strict */
+	jeq	%r0, 0, .Lipv4
+	stb	[%r9 + 0], ':'
+	stb	[%r9 + 1], ':'
+	stb	[%r9 + 2], 'f'
+	stb	[%r9 + 3], 'f'
+	stb	[%r9 + 4], 'f'
+	stb	[%r9 + 5], 'f'
+	stb	[%r9 + 6], ':'
+	add	%r9, 7
+
 .Lipv4:
 	/* Output the last two words as an IPv4 address and return. */
 	mov	%r1, %r6

libdtrace/dt_cg.c

@@ -5941,6 +5941,8 @@ static void
 dt_cg_subr_inet_ntoa6(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
 {
 	dtrace_hdl_t	*dtp = yypcb->pcb_hdl;
+	dt_node_t	*addr = dnp->dn_args;
+	dt_node_t	*strict = addr->dn_list;
 	ssize_t		tbloff;
 	/*
 	 * This table encodes the start and length of the longest run of 0 bits
@@ -5986,14 +5988,19 @@ dt_cg_subr_inet_ntoa6(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
 			0x53, 0x52, 0x70, 0x70, 0x62, 0x70, 0x70, 0x70,
 	};
 
+	if (strict != NULL && strict->dn_kind != DT_NODE_INT)
+		dnerror(strict, D_PROTO_ARG, "inet_ntoa6( ) argument #2 "
+			"must be an integer constant\n");
+
 	tbloff = dt_rodata_insert(dtp->dt_rodata, tbl, 256);
 	if (tbloff == -1L)
 		longjmp(yypcb->pcb_jmpbuf, EDT_NOMEM);
 	if (tbloff > DIF_STROFF_MAX)
 		longjmp(yypcb->pcb_jmpbuf, EDT_STR2BIG);
 
 	dt_cg_subr_arg_to_tstring(dnp, dlp, drp, "dt_inet_ntoa6",
-				  DT_ISIMM, tbloff, DT_IGNOR, 0);
+				  DT_ISIMM, tbloff,
+				  DT_ISIMM, strict && strict->dn_value ? 1 : 0);
 }
 
 static void
@@ -6027,8 +6034,9 @@ dt_cg_subr_inet_ntop(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
 	ddp->dd_ctfp = anp->dn_ctfp;
 	ddp->dd_type = anp->dn_type;
 	xnp = dt_node_type(ddp);		/* frees ddp */
-	/* Create a node to represent: (type)addr */
-	xnp = dt_node_op2(DT_TOK_LPAR, xnp, addr);
+	xnp = dt_node_op2(DT_TOK_LPAR, xnp, addr); /* (type)addr */
+	xnp->dn_list = dt_node_int(1);
+
 	lnp->dn_args = xnp;			/* inet_ntoa6((type)addr) */
 
 	/* Create a node for the function call: inet_ntoa(addr) */
@@ -6043,7 +6051,6 @@ dt_cg_subr_inet_ntop(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
 	ddp->dd_ctfp = anp->dn_ctfp;
 	ddp->dd_type = anp->dn_type;
 	xnp = dt_node_type(ddp);		/* frees ddp */
-
 	xnp = dt_node_op2(DT_TOK_LPAR, xnp, addr); /* (type)addr */
 	rnp->dn_args = xnp;			/* inet_ntoa((type)addr) */
 

libdtrace/dt_open.c

@@ -202,7 +202,7 @@ static const dt_ident_t _dtrace_globals[] = {
 { "inet_ntoa", DT_IDENT_FUNC, DT_IDFLG_DPTR, DIF_SUBR_INET_NTOA, DT_ATTR_STABCMN,
 	DT_VERS_1_5, &dt_idops_func, "string(ipaddr_t *)" },
 { "inet_ntoa6", DT_IDENT_FUNC, DT_IDFLG_DPTR, DIF_SUBR_INET_NTOA6, DT_ATTR_STABCMN,
-	DT_VERS_1_5, &dt_idops_func, "string(struct in6_addr *)" },
+	DT_VERS_1_5, &dt_idops_func, "string(struct in6_addr *, [int])" },
 { "inet_ntop", DT_IDENT_FUNC, DT_IDFLG_DPTR, DIF_SUBR_INET_NTOP, DT_ATTR_STABCMN,
 	DT_VERS_1_5, &dt_idops_func, "string(int, void *)" },
 { "ipl", DT_IDENT_SCALAR, 0, DIF_VAR_IPL, DT_ATTR_STABCMN, DT_VERS_1_0,

test/unittest/funcs/inet_ntoa6/err.D_PROTO_ARG.inet_ntoa6.arg1_not_in6_addr.d

@@ -0,0 +1,19 @@
+/*
+ * Oracle Linux DTrace.
+ * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * Licensed under the Universal Permissive License v 1.0 as shown at
+ * http://oss.oracle.com/licenses/upl.
+ */
+
+#pragma D option quiet
+
+int *p;
+
+BEGIN
+{
+	p = alloca(sizeof(int) * 4);
+	p[3] = htonl(0x7f000001);
+	trace(inet_ntoa6(p));
+
+	exit(0);
+}

test/unittest/funcs/inet_ntoa6/err.D_PROTO_ARG.inet_ntoa6.arg2_not_const.d

@@ -0,0 +1,20 @@
+/*
+ * Oracle Linux DTrace.
+ * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * Licensed under the Universal Permissive License v 1.0 as shown at
+ * http://oss.oracle.com/licenses/upl.
+ */
+
+#pragma D option quiet
+
+int *p;
+
+BEGIN
+{
+	p = alloca(sizeof(int) * 4);
+	n = 0;
+	p[3] = htonl(0x7f000001);
+	trace(inet_ntoa6((struct in6_addr *)p, n));
+
+	exit(0);
+}

test/unittest/funcs/inet_ntoa6/err.D_PROTO_ARG.inet_ntoa6.arg2_not_int.d

@@ -0,0 +1,19 @@
+/*
+ * Oracle Linux DTrace.
+ * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * Licensed under the Universal Permissive License v 1.0 as shown at
+ * http://oss.oracle.com/licenses/upl.
+ */
+
+#pragma D option quiet
+
+int *p;
+
+BEGIN
+{
+	p = alloca(sizeof(int) * 4);
+	p[3] = htonl(0x7f000001);
+	trace(inet_ntoa6((struct in6_addr *)p, ""));
+
+	exit(0);
+}

test/unittest/funcs/inet_ntoa6/err.D_PROTO_LEN.inet_ntoa6.too_few_args.d

@@ -0,0 +1,15 @@
+/*
+ * Oracle Linux DTrace.
+ * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * Licensed under the Universal Permissive License v 1.0 as shown at
+ * http://oss.oracle.com/licenses/upl.
+ */
+
+#pragma D option quiet
+
+BEGIN
+{
+	inet_ntoa6();
+
+	exit(0);
+}

test/unittest/funcs/inet_ntoa6/err.D_PROTO_LEN.inet_ntoa6.too_many_args.d

@@ -0,0 +1,15 @@
+/*
+ * Oracle Linux DTrace.
+ * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * Licensed under the Universal Permissive License v 1.0 as shown at
+ * http://oss.oracle.com/licenses/upl.
+ */
+
+#pragma D option quiet
+
+BEGIN
+{
+	inet_ntoa6(0, 0, 0);
+
+	exit(0);
+}

test/unittest/funcs/inet_ntoa6/tst.inet_ntoa6.strict-0.d

@@ -0,0 +1,19 @@
+/*
+ * Oracle Linux DTrace.
+ * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * Licensed under the Universal Permissive License v 1.0 as shown at
+ * http://oss.oracle.com/licenses/upl.
+ */
+
+#pragma D option quiet
+
+int *p;
+
+BEGIN
+{
+	p = alloca(sizeof(int) * 4);
+	p[3] = htonl(0x7f000001);
+	trace(inet_ntoa6((struct in6_addr *)p, 0));
+
+	exit(0);
+}

test/unittest/funcs/inet_ntoa6/tst.inet_ntoa6.strict-0.r

@@ -0,0 +1 @@
+127.0.0.1

test/unittest/funcs/inet_ntoa6/tst.inet_ntoa6.strict-1.d

@@ -0,0 +1,19 @@
+/*
+ * Oracle Linux DTrace.
+ * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * Licensed under the Universal Permissive License v 1.0 as shown at
+ * http://oss.oracle.com/licenses/upl.
+ */
+
+#pragma D option quiet
+
+int *p;
+
+BEGIN
+{
+	p = alloca(sizeof(int) * 4);
+	p[3] = htonl(0x7f000001);
+	trace(inet_ntoa6((struct in6_addr *)p, 1));
+
+	exit(0);
+}

test/unittest/funcs/inet_ntoa6/tst.inet_ntoa6.strict-1.r

@@ -0,0 +1 @@
+::127.0.0.1

test/unittest/funcs/inet_ntoa6/tst.inet_ntoa6.strict-not-0.d

@@ -0,0 +1,19 @@
+/*
+ * Oracle Linux DTrace.
+ * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * Licensed under the Universal Permissive License v 1.0 as shown at
+ * http://oss.oracle.com/licenses/upl.
+ */
+
+#pragma D option quiet
+
+int *p;
+
+BEGIN
+{
+	p = alloca(sizeof(int) * 4);
+	p[3] = htonl(0x7f000001);
+	trace(inet_ntoa6((struct in6_addr *)p, 42));
+
+	exit(0);
+}

test/unittest/funcs/inet_ntoa6/tst.inet_ntoa6.strict-not-0.r

@@ -0,0 +1 @@
+::127.0.0.1

test/unittest/funcs/tst.inet_ntop_runtime_af.r

@@ -6,7 +6,7 @@ fe80::214:4fff:fe0b:76c8
 1080::808:c:417a
 ::1
 ::
-127.0.0.1
-127.0.0.1
+::127.0.0.1
+::ffff:127.0.0.1
 ::fffe:7f00:1