[10/17] src: ct: add eval part to inject dependencies for ct saddr/daddr

Submitted by Florian Westphal on June 28, 2017, 10:06 a.m.

Details

Message ID 20170628100659.26976-11-fw@strlen.de
State Changes Requested
Delegated to: Pablo Neira
Headers show

Commit Message

Florian Westphal June 28, 2017, 10:06 a.m.
nft has enough context to determine if a dependeny is needed.

add rule ip filter ct original ip6 saddr
allows nft to generate an error due to conflicting bases (ip vs ip6).

add rule inet filter ct original ip6 saddr
allows nft to inject an ipv6 dependency expression.

add rule inet filter ct original saddr
will print an error and will suggest to add ip/ip6 keyword.

Delinerize and print support will be added in followup patches.

Signed-off-by: Florian Westphal <fw@strlen.de>
---
 src/ct.c       | 26 +++++++++++-----------
 src/evaluate.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 77 insertions(+), 19 deletions(-)

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diff --git a/src/ct.c b/src/ct.c
index a4ea6192074a..a5fd04ffbfaa 100644
--- a/src/ct.c
+++ b/src/ct.c
@@ -308,21 +308,21 @@  static void ct_expr_clone(struct expr *new, const struct expr *expr)
 static void ct_expr_pctx_update(struct proto_ctx *ctx, const struct expr *expr)
 {
 	const struct expr *left = expr->left, *right = expr->right;
-	const struct proto_desc *base, *desc;
+	const struct proto_desc *base = NULL, *desc;
+	uint32_t nhproto;
 
 	assert(expr->op == OP_EQ);
 
-	switch (left->ct.key) {
-	case NFT_CT_PROTOCOL:
-		base = ctx->protocol[PROTO_BASE_NETWORK_HDR].desc;
-		desc = proto_find_upper(base, mpz_get_uint32(right->value));
+	nhproto = mpz_get_uint32(right->value);
 
-		proto_ctx_update(ctx, PROTO_BASE_TRANSPORT_HDR,
-				 &expr->location, desc);
-		break;
-	default:
-		break;
-	}
+	base = ctx->protocol[left->ct.base].desc;
+	if (!base)
+		return;
+	desc = proto_find_upper(base, nhproto);
+	if (!desc)
+		return;
+
+	proto_ctx_update(ctx, left->ct.base + 1, &expr->location, desc);
 }
 
 static const struct expr_ops ct_expr_ops = {
@@ -389,10 +389,11 @@  void ct_expr_update_type(struct proto_ctx *ctx, struct expr *expr)
 {
 	const struct proto_desc *desc;
 
+	desc = ctx->protocol[expr->ct.base].desc;
+
 	switch (expr->ct.key) {
 	case NFT_CT_SRC:
 	case NFT_CT_DST:
-		desc = ctx->protocol[PROTO_BASE_NETWORK_HDR].desc;
 		if (desc == &proto_ip)
 			expr->dtype = &ipaddr_type;
 		else if (desc == &proto_ip6)
@@ -402,7 +403,6 @@  void ct_expr_update_type(struct proto_ctx *ctx, struct expr *expr)
 		break;
 	case NFT_CT_PROTO_SRC:
 	case NFT_CT_PROTO_DST:
-		desc = ctx->protocol[PROTO_BASE_TRANSPORT_HDR].desc;
 		if (desc == NULL)
 			break;
 		expr->dtype = &inet_service_type;
diff --git a/src/evaluate.c b/src/evaluate.c
index ca8b63b74fdc..2d63de0c84e4 100644
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -685,27 +685,85 @@  static int expr_evaluate_rt(struct eval_ctx *ctx, struct expr **expr)
 	return expr_evaluate_primary(ctx, expr);
 }
 
+static int ct_gen_nh_dependency(struct eval_ctx *ctx, struct expr *ct)
+{
+	const struct proto_desc *base, *base_now;
+	struct expr *left, *right, *dep;
+	struct stmt *nstmt = NULL;
+
+	base_now = ctx->pctx.protocol[PROTO_BASE_NETWORK_HDR].desc;
+
+	switch (ct->ct.nfproto) {
+	case NFPROTO_IPV4:
+		base = &proto_ip;
+		break;
+	case NFPROTO_IPV6:
+		base = &proto_ip6;
+		break;
+	default:
+		base = ctx->pctx.protocol[PROTO_BASE_NETWORK_HDR].desc;
+		if (base == &proto_ip)
+			ct->ct.nfproto = NFPROTO_IPV4;
+		else if (base == &proto_ip)
+			ct->ct.nfproto = NFPROTO_IPV6;
+
+		if (base)
+			break;
+
+		return expr_error(ctx->msgs, ct,
+				  "cannot determine ip protocol version, use \"ip %1$caddr\" or \"ip6 %1$caddr\" instead",
+				  ct->ct.key == NFT_CT_SRC ? 's' : 'd');
+	}
+
+	/* no additional dependency needed? */
+	if (base == base_now)
+		return 0;
+
+	if (base_now && base_now != base)
+		return expr_error(ctx->msgs, ct,
+				  "conflicting dependencies: %s vs. %s\n",
+				  base->name,
+				  ctx->pctx.protocol[PROTO_BASE_NETWORK_HDR].desc->name);
+	switch (ctx->pctx.family) {
+	case NFPROTO_IPV4:
+	case NFPROTO_IPV6:
+		return 0;
+	}
+
+	left = ct_expr_alloc(&ct->location, NFT_CT_L3PROTOCOL, ct->ct.direction, ct->ct.nfproto);
+
+	right = constant_expr_alloc(&ct->location, left->dtype,
+				    left->dtype->byteorder, left->len,
+				    constant_data_ptr(ct->ct.nfproto, left->len));
+	dep = relational_expr_alloc(&ct->location, OP_EQ, left, right);
+
+	left->ops->pctx_update(&ctx->pctx, dep);
+
+	nstmt = expr_stmt_alloc(&dep->location, dep);
+
+	list_add_tail(&nstmt->list, &ctx->stmt->list);
+	return 0;
+}
+
 /*
  * CT expression: update the protocol dependant types bases on the protocol
  * context.
  */
 static int expr_evaluate_ct(struct eval_ctx *ctx, struct expr **expr)
 {
-	const struct proto_desc *base;
 	struct expr *ct = *expr;
 
-	ct_expr_update_type(&ctx->pctx, ct);
-
-	base = ctx->pctx.protocol[PROTO_BASE_NETWORK_HDR].desc;
 	switch (ct->ct.key) {
 	case NFT_CT_SRC:
 	case NFT_CT_DST:
-		if (base != &proto_ip && base != &proto_ip6)
-			return expr_error_base(ctx->msgs, ct);
+		ct_gen_nh_dependency(ctx, ct);
+		break;
 	default:
 		break;
 	}
 
+	ct_expr_update_type(&ctx->pctx, ct);
+
 	return expr_evaluate_primary(ctx, expr);
 }