[nft PATCH v2] src: Convert ip {s,d}addr to IPv4-mapped as needed

[nft PATCH v2] src: Convert ip {s,d}addr to IPv4-mapped as needed

[Phil Sutter]

In order to reuse IPv6 address-based data structures like sets and maps
with IPv4 packets, if a relational's RHS data type is ip6addr_type, turn
these payload expressions into binop expressions with new OP_V6MAP
internally to have them produce IPv4-mapped IPv6 addresses from the
packet-extracted data as described in RFC4291 section 2.5.5.2[1].

Since the adjustment merely consists of injecting an immediate
expression, no specific kernel support is required for this feature.

Upon deserialization of an ip {s,d}addr expression, the new construct is
detected by probing for a previous immediate expression loading the
expected value into preceeding registers.

Special casing is needed in binop_expr_clone() and expr_postprocess() to
avoid expr->right dereference and to maintain payload expression's
behaviour regarding OP_EQ printing.

While at it, fix documentation of accepted IPv4 address notations: While
dotted hexadecimal is not accepted at all, dotted octal works with
two-digit numbers only (the scanner expects at most three digits).
Therefore drop both from the list.

[1] https://www.rfc-editor.org/rfc/rfc4291#section-2.5.5.2

Signed-off-by: Phil Sutter <phil@nwl.cc>
---
Changes since v1:
- This is v2 of "src: Implement ip {s,d}addr6 expressions" avoiding the
  introduction of new keywords.

Note that adding IPv4 addresses to sets of type ip6addr_type is still
rejected although easily enabled by passing AI_V4MAPPED flag to
getaddrinfo(): Since this also resolves DNS names, users may
unexpectedly add a host's IPv4 address in mapped notation if the name
doesn't resolve to an IPv6 address for whatever reason. If we really
want to open this can of worms, it deserves a separate patch anyway.
---
 doc/data-types.txt              |   5 +-
 doc/payload-expression.txt      |   4 +
 include/expression.h            |   1 +
 src/evaluate.c                  |   9 +++
 src/expression.c                |   9 ++-
 src/json.c                      |   3 +
 src/netlink_delinearize.c       |  33 ++++++++
 src/netlink_linearize.c         |  18 +++++
 tests/py/ip/ip.t                |  16 ++++
 tests/py/ip/ip.t.json           | 128 ++++++++++++++++++++++++++++++++
 tests/py/ip/ip.t.json.output    |  60 +++++++++++++++
 tests/py/ip/ip.t.payload        |  37 +++++++++
 tests/py/ip/ip.t.payload.bridge |  49 ++++++++++++
 tests/py/ip/ip.t.payload.inet   |  49 ++++++++++++
 tests/py/ip/ip.t.payload.netdev |  49 ++++++++++++
 15 files changed, 467 insertions(+), 3 deletions(-)

diff --git a/doc/data-types.txt b/doc/data-types.txt
index e44308b5322cb..d6bdac0b10c06 100644
--- a/doc/data-types.txt
+++ b/doc/data-types.txt
@@ -116,7 +116,7 @@ integer
 |===================
 
 The IPv4 address type is used for IPv4 addresses. Addresses are specified in
-either dotted decimal, dotted hexadecimal, dotted octal, decimal, hexadecimal,
+either dotted decimal, IPv4-mapped (::ffff:0:0/96), decimal, hexadecimal,
 octal notation or as a host name. A host name will be resolved using the
 standard system resolver.
 
@@ -125,6 +125,9 @@ standard system resolver.
 # dotted decimal notation
 filter output ip daddr 127.0.0.1
 
+# IPv4-mapped notation
+filter output ip daddr ::ffff:127.0.0.1
+
 # host name
 filter output ip daddr localhost
 ----------------------------
diff --git a/doc/payload-expression.txt b/doc/payload-expression.txt
index 8b538968c84b5..3c2cb4d39410a 100644
--- a/doc/payload-expression.txt
+++ b/doc/payload-expression.txt
@@ -141,6 +141,10 @@ gro_ipv4_max_size and gso_ipv4_max_size), then *ip length* might be 0 for such
 jumbo packets. *meta length* allows you to match on the packet length including
 the IP header size.
 
+If needed, *ip saddr* and *ip daddr* expressions are converted to produce
+IPv4-mapped IPv6 addresses (e.g. ::ffff:1.2.3.4). This way, a common set or map
+with key type *ipv6_addr* may be used for both IPv4 and IPv6 packets.
+
 ICMP HEADER EXPRESSION
 ~~~~~~~~~~~~~~~~~~~~~~
 [verse]
diff --git a/include/expression.h b/include/expression.h
index a960f8cb8b087..1e494b3f14230 100644
--- a/include/expression.h
+++ b/include/expression.h
@@ -107,6 +107,7 @@ enum ops {
 	OP_LTE,
 	OP_GTE,
 	OP_NEG,
+	OP_V6MAP,
 	__OP_MAX
 };
 #define OP_MAX		(__OP_MAX - 1)
diff --git a/src/evaluate.c b/src/evaluate.c
index 4be5299274d26..179b192c6f4d1 100644
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -991,6 +991,7 @@ static bool payload_needs_adjustment(const struct expr *expr)
 
 static int expr_evaluate_payload(struct eval_ctx *ctx, struct expr **exprp)
 {
+	const struct datatype *dtype = ctx->ectx.dtype;
 	const struct expr *key = ctx->ectx.key;
 	struct expr *expr = *exprp;
 
@@ -1012,6 +1013,14 @@ static int expr_evaluate_payload(struct eval_ctx *ctx, struct expr **exprp)
 			return err;
 	}
 
+	if (expr->dtype == &ipaddr_type && dtype == &ip6addr_type) {
+		*exprp = binop_expr_alloc(&expr->location,
+					  OP_V6MAP, expr, NULL);
+		datatype_set(*exprp, &ip6addr_type);
+		(*exprp)->len = ip6addr_type.size;
+		return 0;
+	}
+
 	expr->payload.evaluated = true;
 
 	return 0;
diff --git a/src/expression.c b/src/expression.c
index 4d68967f112e4..17bc613b23551 100644
--- a/src/expression.c
+++ b/src/expression.c
@@ -854,13 +854,17 @@ bool must_print_eq_op(const struct expr *expr)
 	    expr->right->etype == EXPR_VALUE)
 		return true;
 
-	return expr->left->etype == EXPR_BINOP;
+	return expr->left->etype == EXPR_BINOP &&
+	       expr->left->op != OP_V6MAP;
 }
 
 static void binop_expr_print(const struct expr *expr, struct output_ctx *octx)
 {
 	binop_arg_print(expr, expr->left, octx);
 
+	if (expr->op == OP_V6MAP)
+		return;
+
 	if (expr_op_symbols[expr->op] &&
 	    (expr->op != OP_EQ || must_print_eq_op(expr)))
 		nft_print(octx, " %s ", expr_op_symbols[expr->op]);
@@ -873,7 +877,8 @@ static void binop_expr_print(const struct expr *expr, struct output_ctx *octx)
 static void binop_expr_clone(struct expr *new, const struct expr *expr)
 {
 	new->left  = expr_clone(expr->left);
-	new->right = expr_clone(expr->right);
+	if (expr->right)
+		new->right = expr_clone(expr->right);
 }
 
 static void binop_expr_destroy(struct expr *expr)
diff --git a/src/json.c b/src/json.c
index 9fb6d715a53de..9a10d8ae6298b 100644
--- a/src/json.c
+++ b/src/json.c
@@ -668,6 +668,9 @@ __binop_expr_json(int op, const struct expr *expr, struct output_ctx *octx)
 
 json_t *binop_expr_json(const struct expr *expr, struct output_ctx *octx)
 {
+	if (expr->op == OP_V6MAP)
+		return payload_expr_json(expr->left, octx);
+
 	return nft_json_pack("{s:o}", expr_op_symbols[expr->op],
 			 __binop_expr_json(expr->op, expr, octx));
 }
diff --git a/src/netlink_delinearize.c b/src/netlink_delinearize.c
index 9561e298aebb5..061178e2ade9b 100644
--- a/src/netlink_delinearize.c
+++ b/src/netlink_delinearize.c
@@ -17,6 +17,7 @@
 #include <linux/netfilter/nf_nat.h>
 #include <linux/netfilter.h>
 #include <net/ethernet.h>
+#include <netinet/ip.h>
 #include <netlink.h>
 #include <rule.h>
 #include <statement.h>
@@ -649,10 +650,31 @@ static void netlink_parse_byteorder(struct netlink_parse_ctx *ctx,
 	netlink_set_register(ctx, dreg, expr);
 }
 
+static bool payload_is_ip_addr(const struct expr *expr)
+{
+	size_t saddr_offset = offsetof(struct iphdr, saddr) * BITS_PER_BYTE;
+	size_t daddr_offset = offsetof(struct iphdr, daddr) * BITS_PER_BYTE;
+
+	return expr->payload.base == PROTO_BASE_NETWORK_HDR &&
+	       expr->len == ipaddr_type.size &&
+	       (expr->payload.offset == saddr_offset ||
+		expr->payload.offset == daddr_offset);
+}
+
+static bool immediate_is_v6map_pfx(const struct expr *expr)
+{
+	return expr &&
+	       expr->etype == EXPR_VALUE &&
+	       expr->len == ip6addr_type.size - ipaddr_type.size &&
+	       !mpz_cmp_ui(expr->value, 0xffff);
+}
+
 static void netlink_parse_payload_expr(struct netlink_parse_ctx *ctx,
 				       const struct location *loc,
 				       const struct nftnl_expr *nle)
 {
+	size_t v6map_reg_off = (sizeof(struct in6_addr) -
+				sizeof(struct in_addr)) / NFT_REG32_SIZE;
 	enum nft_registers dreg;
 	uint32_t base, offset, len;
 	struct expr *expr;
@@ -670,6 +692,15 @@ static void netlink_parse_payload_expr(struct netlink_parse_ctx *ctx,
 
 	dreg = netlink_parse_register(nle, NFTNL_EXPR_PAYLOAD_DREG);
 
+	if (dreg >= v6map_reg_off &&
+	    payload_is_ip_addr(expr) &&
+	    immediate_is_v6map_pfx(ctx->registers[dreg - v6map_reg_off])) {
+		expr = binop_expr_alloc(loc, OP_V6MAP, expr, NULL);
+		datatype_set(expr, &ip6addr_type);
+		expr->len = ip6addr_type.size;
+		dreg -= v6map_reg_off;
+	}
+
 	if (ctx->inner)
 		ctx->inner_reg = dreg;
 
@@ -2925,6 +2956,8 @@ static void expr_postprocess(struct rule_pp_ctx *ctx, struct expr **exprp)
 				return;
 			}
 			break;
+		case OP_V6MAP:
+			return;
 		default:
 			if (expr->right->len > expr->left->len) {
 				expr_set_type(expr->right, expr->left->dtype,
diff --git a/src/netlink_linearize.c b/src/netlink_linearize.c
index 30bc0094cc7e6..1d90e49ba44bd 100644
--- a/src/netlink_linearize.c
+++ b/src/netlink_linearize.c
@@ -798,6 +798,21 @@ static void netlink_gen_bitwise_bool(struct netlink_linearize_ctx *ctx,
 	nftnl_rule_add_expr(ctx->nlr, nle);
 }
 
+static void netlink_gen_v6map(struct netlink_linearize_ctx *ctx,
+			      const struct expr *expr, enum nft_registers dreg)
+{
+	const uint16_t pfx[6] = { 0, 0, 0, 0, 0, 0xffff };
+	struct nftnl_expr *nle;
+
+	nle = alloc_nft_expr("immediate");
+	netlink_put_register(nle, NFTNL_EXPR_IMM_DREG, dreg);
+	nftnl_expr_set(nle, NFTNL_EXPR_IMM_DATA, pfx, sizeof(pfx));
+	nftnl_rule_add_expr(ctx->nlr, nle);
+
+	dreg += netlink_register_space(sizeof(pfx) * BITS_PER_BYTE);
+	netlink_gen_expr(ctx, expr->left, dreg);
+}
+
 static void netlink_gen_binop(struct netlink_linearize_ctx *ctx,
 			      const struct expr *expr,
 			      enum nft_registers dreg)
@@ -807,6 +822,9 @@ static void netlink_gen_binop(struct netlink_linearize_ctx *ctx,
 	case OP_RSHIFT:
 		netlink_gen_bitwise_shift(ctx, expr, dreg);
 		break;
+	case OP_V6MAP:
+		netlink_gen_v6map(ctx, expr, dreg);
+		break;
 	default:
 		if (expr_is_constant(expr->right))
 			netlink_gen_bitwise_mask_xor(ctx, expr, dreg);
diff --git a/tests/py/ip/ip.t b/tests/py/ip/ip.t
index 47262d9a43617..2b218015afdc0 100644
--- a/tests/py/ip/ip.t
+++ b/tests/py/ip/ip.t
@@ -7,6 +7,13 @@
 *bridge;test-bridge;input
 *netdev;test-netdev;ingress,egress
 
+!ip6addrset type ipv6_addr;ok
+?ip6addrset feed::c0:ffee, ::ffff:1.2.3.4;ok
+!v4v6set type ipv4_addr . ipv6_addr;ok
+?v4v6set 1.2.3.4 . ::ffff:5.6.7.8;ok
+!v6v4set type ipv6_addr . ipv4_addr;ok
+?v6v4set ::ffff:5.6.7.8 . 1.2.3.4;ok
+
 - ip version 2;ok
 
 # bug ip hdrlength
@@ -110,6 +117,15 @@ ip saddr & 0.0.0.255 < 0.0.0.127;ok
 
 ip saddr & 0xffff0000 == 0xffff0000;ok;ip saddr 255.255.0.0/16
 
+ip saddr ::ffff:1.2.3.4;ok;ip saddr 1.2.3.4
+ip daddr ::ffff:1.2.3.4;ok;ip daddr 1.2.3.4
+ip saddr { ::ffff:1.2.3.4, feed::c0:ff:ee };fail
+ip daddr { ::ffff:1.2.3.4, feed::c0:ff:ee };fail
+ip saddr ::ffff:1.2.3.4 ip daddr 5.6.7.8;ok;ip saddr 1.2.3.4 ip daddr 5.6.7.8
+ip saddr @ip6addrset;ok
+ip saddr . ip daddr @v4v6set;ok
+ip saddr . ip daddr @v6v4set;ok
+
 ip version 4 ip hdrlength 5;ok
 ip hdrlength 0;ok
 ip hdrlength 15;ok
diff --git a/tests/py/ip/ip.t.json b/tests/py/ip/ip.t.json
index 3c3a12d7117ce..bf15cca406ec1 100644
--- a/tests/py/ip/ip.t.json
+++ b/tests/py/ip/ip.t.json
@@ -1350,6 +1350,134 @@
     }
 ]
 
+# ip saddr ::ffff:1.2.3.4
+[
+    {
+        "match": {
+            "left": {
+                "payload": {
+                    "field": "saddr",
+                    "protocol": "ip"
+                }
+            },
+            "op": "==",
+            "right": "::ffff:1.2.3.4"
+        }
+    }
+]
+
+# ip daddr ::ffff:1.2.3.4
+[
+    {
+        "match": {
+            "left": {
+                "payload": {
+                    "field": "daddr",
+                    "protocol": "ip"
+                }
+            },
+            "op": "==",
+            "right": "::ffff:1.2.3.4"
+        }
+    }
+]
+
+# ip saddr ::ffff:1.2.3.4 ip daddr 5.6.7.8
+[
+    {
+        "match": {
+            "left": {
+                "payload": {
+                    "field": "saddr",
+                    "protocol": "ip"
+                }
+            },
+            "op": "==",
+            "right": "::ffff:1.2.3.4"
+        }
+    },
+    {
+        "match": {
+            "left": {
+                "payload": {
+                    "field": "daddr",
+                    "protocol": "ip"
+                }
+            },
+            "op": "==",
+            "right": "5.6.7.8"
+        }
+    }
+]
+
+# ip saddr @ip6addrset
+[
+    {
+        "match": {
+            "left": {
+                "payload": {
+                    "field": "saddr",
+                    "protocol": "ip"
+                }
+            },
+            "op": "==",
+            "right": "@ip6addrset"
+        }
+    }
+]
+
+# ip saddr . ip daddr @v4v6set
+[
+    {
+        "match": {
+            "left": {
+                "concat": [
+                    {
+                        "payload": {
+                            "field": "saddr",
+                            "protocol": "ip"
+                        }
+                    },
+                    {
+                        "payload": {
+                            "field": "daddr",
+                            "protocol": "ip"
+                        }
+                    }
+                ]
+            },
+            "op": "==",
+            "right": "@v4v6set"
+        }
+    }
+]
+
+# ip saddr . ip daddr @v6v4set
+[
+    {
+        "match": {
+            "left": {
+                "concat": [
+                    {
+                        "payload": {
+                            "field": "saddr",
+                            "protocol": "ip"
+                        }
+                    },
+                    {
+                        "payload": {
+                            "field": "daddr",
+                            "protocol": "ip"
+                        }
+                    }
+                ]
+            },
+            "op": "==",
+            "right": "@v6v4set"
+        }
+    }
+]
+
 # ip version 4 ip hdrlength 5
 [
     {
diff --git a/tests/py/ip/ip.t.json.output b/tests/py/ip/ip.t.json.output
index 351ae93549fa6..8155e44c558f7 100644
--- a/tests/py/ip/ip.t.json.output
+++ b/tests/py/ip/ip.t.json.output
@@ -206,6 +206,66 @@
     }
 ]
 
+# ip saddr ::ffff:1.2.3.4
+[
+    {
+        "match": {
+            "left": {
+                "payload": {
+                    "field": "saddr",
+                    "protocol": "ip"
+                }
+            },
+            "op": "==",
+            "right": "1.2.3.4"
+        }
+    }
+]
+
+# ip daddr ::ffff:1.2.3.4
+[
+    {
+        "match": {
+            "left": {
+                "payload": {
+                    "field": "daddr",
+                    "protocol": "ip"
+                }
+            },
+            "op": "==",
+            "right": "1.2.3.4"
+        }
+    }
+]
+
+# ip saddr ::ffff:1.2.3.4 ip daddr 5.6.7.8
+[
+    {
+        "match": {
+            "left": {
+                "payload": {
+                    "field": "saddr",
+                    "protocol": "ip"
+                }
+            },
+            "op": "==",
+            "right": "1.2.3.4"
+        }
+    },
+    {
+        "match": {
+            "left": {
+                "payload": {
+                    "field": "daddr",
+                    "protocol": "ip"
+                }
+            },
+            "op": "==",
+            "right": "5.6.7.8"
+        }
+    }
+]
+
 # iif "lo" ip ecn set 1
 [
     {
diff --git a/tests/py/ip/ip.t.payload b/tests/py/ip/ip.t.payload
index 0e9936278008b..dfd90028a7475 100644
--- a/tests/py/ip/ip.t.payload
+++ b/tests/py/ip/ip.t.payload
@@ -413,6 +413,43 @@ ip test-ip4 input
   [ bitwise reg 1 = ( reg 1 & 0x0000ffff ) ^ 0x00000000 ]
   [ cmp eq reg 1 0x0000ffff ]
 
+# ip saddr ::ffff:1.2.3.4
+ip test-ip4 input
+  [ payload load 4b @ network header + 12 => reg 1 ]
+  [ cmp eq reg 1 0x04030201 ]
+
+# ip daddr ::ffff:1.2.3.4
+ip test-ip4 input
+  [ payload load 4b @ network header + 16 => reg 1 ]
+  [ cmp eq reg 1 0x04030201 ]
+
+# ip saddr ::ffff:1.2.3.4 ip daddr 5.6.7.8
+ip test-ip4 input
+  [ payload load 4b @ network header + 12 => reg 1 ]
+  [ cmp eq reg 1 0x04030201 ]
+  [ payload load 4b @ network header + 16 => reg 1 ]
+  [ cmp eq reg 1 0x08070605 ]
+
+# ip saddr @ip6addrset
+ip test-ip4 input
+  [ immediate reg 1 0x00000000 0x00000000 0xffff0000 ]
+  [ payload load 4b @ network header + 12 => reg 11 ]
+  [ lookup reg 1 set ip6addrset ]
+
+# ip saddr . ip daddr @v4v6set
+ip test-ip4 input
+  [ payload load 4b @ network header + 12 => reg 1 ]
+  [ immediate reg 9 0x00000000 0x00000000 0xffff0000 ]
+  [ payload load 4b @ network header + 16 => reg 2 ]
+  [ lookup reg 1 set v4v6set ]
+
+# ip saddr . ip daddr @v6v4set
+ip test-ip4 input
+  [ immediate reg 1 0x00000000 0x00000000 0xffff0000 ]
+  [ payload load 4b @ network header + 12 => reg 11 ]
+  [ payload load 4b @ network header + 16 => reg 2 ]
+  [ lookup reg 1 set v6v4set ]
+
 # ip version 4 ip hdrlength 5
 ip test-ip4 input
   [ payload load 1b @ network header + 0 => reg 1 ]
diff --git a/tests/py/ip/ip.t.payload.bridge b/tests/py/ip/ip.t.payload.bridge
index 663f87d7b4acf..0b1d0cf105ae1 100644
--- a/tests/py/ip/ip.t.payload.bridge
+++ b/tests/py/ip/ip.t.payload.bridge
@@ -549,6 +549,55 @@ bridge test-bridge input
   [ bitwise reg 1 = ( reg 1 & 0x0000ffff ) ^ 0x00000000 ]
   [ cmp eq reg 1 0x0000ffff ]
 
+# ip saddr ::ffff:1.2.3.4
+bridge test-bridge input
+  [ meta load protocol => reg 1 ]
+  [ cmp eq reg 1 0x00000008 ]
+  [ payload load 4b @ network header + 12 => reg 1 ]
+  [ cmp eq reg 1 0x04030201 ]
+
+# ip daddr ::ffff:1.2.3.4
+bridge test-bridge input
+  [ meta load protocol => reg 1 ]
+  [ cmp eq reg 1 0x00000008 ]
+  [ payload load 4b @ network header + 16 => reg 1 ]
+  [ cmp eq reg 1 0x04030201 ]
+
+# ip saddr ::ffff:1.2.3.4 ip daddr 5.6.7.8
+bridge test-bridge input
+  [ meta load protocol => reg 1 ]
+  [ cmp eq reg 1 0x00000008 ]
+  [ payload load 4b @ network header + 12 => reg 1 ]
+  [ cmp eq reg 1 0x04030201 ]
+  [ payload load 4b @ network header + 16 => reg 1 ]
+  [ cmp eq reg 1 0x08070605 ]
+
+# ip saddr @ip6addrset
+bridge test-bridge input
+  [ meta load protocol => reg 1 ]
+  [ cmp eq reg 1 0x00000008 ]
+  [ immediate reg 1 0x00000000 0x00000000 0xffff0000 ]
+  [ payload load 4b @ network header + 12 => reg 11 ]
+  [ lookup reg 1 set ip6addrset ]
+
+# ip saddr . ip daddr @v4v6set
+bridge test-bridge input
+  [ meta load protocol => reg 1 ]
+  [ cmp eq reg 1 0x00000008 ]
+  [ payload load 4b @ network header + 12 => reg 1 ]
+  [ immediate reg 9 0x00000000 0x00000000 0xffff0000 ]
+  [ payload load 4b @ network header + 16 => reg 2 ]
+  [ lookup reg 1 set v4v6set ]
+
+# ip saddr . ip daddr @v6v4set
+bridge test-bridge input
+  [ meta load protocol => reg 1 ]
+  [ cmp eq reg 1 0x00000008 ]
+  [ immediate reg 1 0x00000000 0x00000000 0xffff0000 ]
+  [ payload load 4b @ network header + 12 => reg 11 ]
+  [ payload load 4b @ network header + 16 => reg 2 ]
+  [ lookup reg 1 set v6v4set ]
+
 # ip version 4 ip hdrlength 5
 bridge test-bridge input 
   [ meta load protocol => reg 1 ]
diff --git a/tests/py/ip/ip.t.payload.inet b/tests/py/ip/ip.t.payload.inet
index b8ab49c871430..50321962402df 100644
--- a/tests/py/ip/ip.t.payload.inet
+++ b/tests/py/ip/ip.t.payload.inet
@@ -549,6 +549,55 @@ inet test-inet input
   [ bitwise reg 1 = ( reg 1 & 0x0000ffff ) ^ 0x00000000 ]
   [ cmp eq reg 1 0x0000ffff ]
 
+# ip saddr ::ffff:1.2.3.4
+inet test-inet input
+  [ meta load nfproto => reg 1 ]
+  [ cmp eq reg 1 0x00000002 ]
+  [ payload load 4b @ network header + 12 => reg 1 ]
+  [ cmp eq reg 1 0x04030201 ]
+
+# ip daddr ::ffff:1.2.3.4
+inet test-inet input
+  [ meta load nfproto => reg 1 ]
+  [ cmp eq reg 1 0x00000002 ]
+  [ payload load 4b @ network header + 16 => reg 1 ]
+  [ cmp eq reg 1 0x04030201 ]
+
+# ip saddr ::ffff:1.2.3.4 ip daddr 5.6.7.8
+inet test-inet input
+  [ meta load nfproto => reg 1 ]
+  [ cmp eq reg 1 0x00000002 ]
+  [ payload load 4b @ network header + 12 => reg 1 ]
+  [ cmp eq reg 1 0x04030201 ]
+  [ payload load 4b @ network header + 16 => reg 1 ]
+  [ cmp eq reg 1 0x08070605 ]
+
+# ip saddr @ip6addrset
+inet test-inet input
+  [ meta load nfproto => reg 1 ]
+  [ cmp eq reg 1 0x00000002 ]
+  [ immediate reg 1 0x00000000 0x00000000 0xffff0000 ]
+  [ payload load 4b @ network header + 12 => reg 11 ]
+  [ lookup reg 1 set ip6addrset ]
+
+# ip saddr . ip daddr @v4v6set
+inet test-inet input
+  [ meta load nfproto => reg 1 ]
+  [ cmp eq reg 1 0x00000002 ]
+  [ payload load 4b @ network header + 12 => reg 1 ]
+  [ immediate reg 9 0x00000000 0x00000000 0xffff0000 ]
+  [ payload load 4b @ network header + 16 => reg 2 ]
+  [ lookup reg 1 set v4v6set ]
+
+# ip saddr . ip daddr @v6v4set
+inet test-inet input
+  [ meta load nfproto => reg 1 ]
+  [ cmp eq reg 1 0x00000002 ]
+  [ immediate reg 1 0x00000000 0x00000000 0xffff0000 ]
+  [ payload load 4b @ network header + 12 => reg 11 ]
+  [ payload load 4b @ network header + 16 => reg 2 ]
+  [ lookup reg 1 set v6v4set ]
+
 # ip version 4 ip hdrlength 5
 inet test-inet input
   [ meta load nfproto => reg 1 ]
diff --git a/tests/py/ip/ip.t.payload.netdev b/tests/py/ip/ip.t.payload.netdev
index bd3495324b918..768eb077b92fe 100644
--- a/tests/py/ip/ip.t.payload.netdev
+++ b/tests/py/ip/ip.t.payload.netdev
@@ -448,6 +448,55 @@ netdev test-netdev ingress
   [ bitwise reg 1 = ( reg 1 & 0x0000ffff ) ^ 0x00000000 ]
   [ cmp eq reg 1 0x0000ffff ]
 
+# ip saddr ::ffff:1.2.3.4
+netdev test-netdev ingress
+  [ meta load protocol => reg 1 ]
+  [ cmp eq reg 1 0x00000008 ]
+  [ payload load 4b @ network header + 12 => reg 1 ]
+  [ cmp eq reg 1 0x04030201 ]
+
+# ip daddr ::ffff:1.2.3.4
+netdev test-netdev ingress
+  [ meta load protocol => reg 1 ]
+  [ cmp eq reg 1 0x00000008 ]
+  [ payload load 4b @ network header + 16 => reg 1 ]
+  [ cmp eq reg 1 0x04030201 ]
+
+# ip saddr ::ffff:1.2.3.4 ip daddr 5.6.7.8
+netdev test-netdev egress
+  [ meta load protocol => reg 1 ]
+  [ cmp eq reg 1 0x00000008 ]
+  [ payload load 4b @ network header + 12 => reg 1 ]
+  [ cmp eq reg 1 0x04030201 ]
+  [ payload load 4b @ network header + 16 => reg 1 ]
+  [ cmp eq reg 1 0x08070605 ]
+
+# ip saddr @ip6addrset
+netdev test-netdev egress
+  [ meta load protocol => reg 1 ]
+  [ cmp eq reg 1 0x00000008 ]
+  [ immediate reg 1 0x00000000 0x00000000 0xffff0000 ]
+  [ payload load 4b @ network header + 12 => reg 11 ]
+  [ lookup reg 1 set ip6addrset ]
+
+# ip saddr . ip daddr @v4v6set
+netdev test-netdev ingress
+  [ meta load protocol => reg 1 ]
+  [ cmp eq reg 1 0x00000008 ]
+  [ payload load 4b @ network header + 12 => reg 1 ]
+  [ immediate reg 9 0x00000000 0x00000000 0xffff0000 ]
+  [ payload load 4b @ network header + 16 => reg 2 ]
+  [ lookup reg 1 set v4v6set ]
+
+# ip saddr . ip daddr @v6v4set
+netdev test-netdev egress
+  [ meta load protocol => reg 1 ]
+  [ cmp eq reg 1 0x00000008 ]
+  [ immediate reg 1 0x00000000 0x00000000 0xffff0000 ]
+  [ payload load 4b @ network header + 12 => reg 11 ]
+  [ payload load 4b @ network header + 16 => reg 2 ]
+  [ lookup reg 1 set v6v4set ]
+
 # ip version 4 ip hdrlength 5
 netdev test-netdev ingress 
   [ meta load protocol => reg 1 ]
-- 
2.51.0

Re: [nft PATCH v2] src: Convert ip {s,d}addr to IPv4-mapped as needed

[Florian Westphal]

Phil Sutter <phil@nwl.cc> wrote:
> Note that adding IPv4 addresses to sets of type ip6addr_type is still
> rejected although easily enabled by passing AI_V4MAPPED flag to
> getaddrinfo(): Since this also resolves DNS names, users may
> unexpectedly add a host's IPv4 address in mapped notation if the name
> doesn't resolve to an IPv6 address for whatever reason. If we really
> want to open this can of worms, it deserves a separate patch anyway.

I think we should force AI_NUMERICHOST when AI_V4MAPPED gets added, i.e.
never autofill in a v4mapped address for ip6addr_type when all we had
was a name.

> +# ip saddr ::ffff:1.2.3.4
> +ip test-ip4 input
> +  [ payload load 4b @ network header + 12 => reg 1 ]
> +  [ cmp eq reg 1 0x04030201 ]

Makes sense, no expansion.

> +# ip saddr @ip6addrset
> +ip test-ip4 input
> +  [ immediate reg 1 0x00000000 0x00000000 0xffff0000 ]
> +  [ payload load 4b @ network header + 12 => reg 11 ]
> +  [ lookup reg 1 set ip6addrset ]

Looks good to me, thanks for working on this.

Re: [nft PATCH v2] src: Convert ip {s,d}addr to IPv4-mapped as needed

[Phil Sutter]

On Wed, Dec 10, 2025 at 04:14:49PM +0100, Florian Westphal wrote:
> Phil Sutter <phil@nwl.cc> wrote:
> > Note that adding IPv4 addresses to sets of type ip6addr_type is still
> > rejected although easily enabled by passing AI_V4MAPPED flag to
> > getaddrinfo(): Since this also resolves DNS names, users may
> > unexpectedly add a host's IPv4 address in mapped notation if the name
> > doesn't resolve to an IPv6 address for whatever reason. If we really
> > want to open this can of worms, it deserves a separate patch anyway.
> 
> I think we should force AI_NUMERICHOST when AI_V4MAPPED gets added, i.e.
> never autofill in a v4mapped address for ip6addr_type when all we had
> was a name.

But this would disable hostname functionality (note we have
NFT_CTX_INPUT_NO_DNS to disable it, so users expect it to be enabled)
and I don't know on which conditions to set AI_V4MAPPED if conditional
setting is desired.

Maybe ip6addr_type_parse() could explicitly try to parse as numeric IPv4
address first? Or a least impact approach checking sym->identifier
consists of dots and digits only?

> > +# ip saddr ::ffff:1.2.3.4
> > +ip test-ip4 input
> > +  [ payload load 4b @ network header + 12 => reg 1 ]
> > +  [ cmp eq reg 1 0x04030201 ]
> 
> Makes sense, no expansion.
> 
> > +# ip saddr @ip6addrset
> > +ip test-ip4 input
> > +  [ immediate reg 1 0x00000000 0x00000000 0xffff0000 ]
> > +  [ payload load 4b @ network header + 12 => reg 11 ]
> > +  [ lookup reg 1 set ip6addrset ]
> 
> Looks good to me, thanks for working on this.

Thanks for your review! The option of converting implicitly didn't
appear to me at all while initially working on it. And for v2, I could
reuse large parts and merely get the chunk in expr_evaluate_payload()
right (if protocol dependencies are created, ctx->ectx gets
overwritten).

Cheers, Phil

Re: [nft PATCH v2] src: Convert ip {s,d}addr to IPv4-mapped as needed

[Florian Westphal]

Phil Sutter <phil@nwl.cc> wrote:
> Maybe ip6addr_type_parse() could explicitly try to parse as numeric IPv4
> address first? Or a least impact approach checking sym->identifier
> consists of dots and digits only?

Sounds good, just try inet_pton(AF_INET, ..) to see if you need
to turn on MAPPED flag.