src: add eval_proto_ctx()

Add eval_proto_ctx() to access protocol context (struct proto_ctx).
Rename struct proto_ctx field to _pctx to highlight that this field
is internal and the helper function should be used.

This patch comes in preparation for supporting outer and inner
protocol context.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 35 insertions, 23 deletions

diff --git a/src/payload.c b/src/payload.c
index 101bfbda..13962ef4 100644
--- a/src/payload.c
+++ b/src/payload.c
@@ -391,9 +391,11 @@ static int payload_add_dependency(struct eval_ctx *ctx,
 {
 	const struct proto_hdr_template *tmpl;
 	struct expr *dep, *left, *right;
+	struct proto_ctx *pctx;
 	struct stmt *stmt;
-	int protocol = proto_find_num(desc, upper);
+	int protocol;
 
+	protocol = proto_find_num(desc, upper);
 	if (protocol < 0)
 		return expr_error(ctx->msgs, expr,
 				  "conflicting protocols specified: %s vs. %s",
@@ -415,15 +417,17 @@ static int payload_add_dependency(struct eval_ctx *ctx,
 		return expr_error(ctx->msgs, expr,
 					  "dependency statement is invalid");
 	}
-	relational_expr_pctx_update(&ctx->pctx, dep);
+
+	pctx = eval_proto_ctx(ctx);
+	relational_expr_pctx_update(pctx, dep);
 	*res = stmt;
 	return 0;
 }
 
 static const struct proto_desc *
-payload_get_get_ll_hdr(const struct eval_ctx *ctx)
+payload_get_get_ll_hdr(const struct proto_ctx *pctx)
 {
-	switch (ctx->pctx.family) {
+	switch (pctx->family) {
 	case NFPROTO_INET:
 		return &proto_inet;
 	case NFPROTO_BRIDGE:
@@ -440,9 +444,11 @@ payload_get_get_ll_hdr(const struct eval_ctx *ctx)
 static const struct proto_desc *
 payload_gen_special_dependency(struct eval_ctx *ctx, const struct expr *expr)
 {
+	struct proto_ctx *pctx = eval_proto_ctx(ctx);
+
 	switch (expr->payload.base) {
 	case PROTO_BASE_LL_HDR:
-		return payload_get_get_ll_hdr(ctx);
+		return payload_get_get_ll_hdr(pctx);
 	case PROTO_BASE_TRANSPORT_HDR:
 		if (expr->payload.desc == &proto_icmp ||
 		    expr->payload.desc == &proto_icmp6 ||
@@ -450,9 +456,9 @@ payload_gen_special_dependency(struct eval_ctx *ctx, const struct expr *expr)
 			const struct proto_desc *desc, *desc_upper;
 			struct stmt *nstmt;
 
-			desc = ctx->pctx.protocol[PROTO_BASE_LL_HDR].desc;
+			desc = pctx->protocol[PROTO_BASE_LL_HDR].desc;
 			if (!desc) {
-				desc = payload_get_get_ll_hdr(ctx);
+				desc = payload_get_get_ll_hdr(pctx);
 				if (!desc)
 					break;
 			}
@@ -502,11 +508,14 @@ payload_gen_special_dependency(struct eval_ctx *ctx, const struct expr *expr)
 int payload_gen_dependency(struct eval_ctx *ctx, const struct expr *expr,
 			   struct stmt **res)
 {
-	const struct hook_proto_desc *h = &hook_proto_desc[ctx->pctx.family];
+	const struct hook_proto_desc *h;
 	const struct proto_desc *desc;
+	struct proto_ctx *pctx;
 	struct stmt *stmt;
 	uint16_t type;
 
+	pctx = eval_proto_ctx(ctx);
+	h = &hook_proto_desc[pctx->family];
 	if (expr->payload.base < h->base) {
 		if (expr->payload.base < h->base - 1)
 			return expr_error(ctx->msgs, expr,
@@ -527,7 +536,7 @@ int payload_gen_dependency(struct eval_ctx *ctx, const struct expr *expr,
 		return 0;
 	}
 
-	desc = ctx->pctx.protocol[expr->payload.base - 1].desc;
+	desc = pctx->protocol[expr->payload.base - 1].desc;
 	/* Special case for mixed IPv4/IPv6 and bridge tables */
 	if (desc == NULL)
 		desc = payload_gen_special_dependency(ctx, expr);
@@ -538,7 +547,7 @@ int payload_gen_dependency(struct eval_ctx *ctx, const struct expr *expr,
 				  "no %s protocol specified",
 				  proto_base_names[expr->payload.base - 1]);
 
-	if (ctx->pctx.family == NFPROTO_BRIDGE && desc == &proto_eth) {
+	if (pctx->family == NFPROTO_BRIDGE && desc == &proto_eth) {
 		/* prefer netdev proto, which adds dependencies based
 		 * on skb->protocol.
 		 *
@@ -563,11 +572,13 @@ int exthdr_gen_dependency(struct eval_ctx *ctx, const struct expr *expr,
 			  enum proto_bases pb, struct stmt **res)
 {
 	const struct proto_desc *desc;
+	struct proto_ctx *pctx;
 
-	desc = ctx->pctx.protocol[pb].desc;
+	pctx = eval_proto_ctx(ctx);
+	desc = pctx->protocol[pb].desc;
 	if (desc == NULL) {
 		if (expr->exthdr.op == NFT_EXTHDR_OP_TCPOPT) {
-			switch (ctx->pctx.family) {
+			switch (pctx->family) {
 			case NFPROTO_NETDEV:
 			case NFPROTO_BRIDGE:
 			case NFPROTO_INET:
@@ -1228,6 +1239,7 @@ __payload_gen_icmp_echo_dependency(struct eval_ctx *ctx, const struct expr *expr
 int payload_gen_icmp_dependency(struct eval_ctx *ctx, const struct expr *expr,
 				struct stmt **res)
 {
+	struct proto_ctx *pctx = eval_proto_ctx(ctx);
 	const struct proto_hdr_template *tmpl;
 	const struct proto_desc *desc;
 	struct stmt *stmt = NULL;
@@ -1244,11 +1256,11 @@ int payload_gen_icmp_dependency(struct eval_ctx *ctx, const struct expr *expr,
 		break;
 	case PROTO_ICMP_ECHO:
 		/* do not test ICMP_ECHOREPLY here: its 0 */
-		if (ctx->pctx.th_dep.icmp.type == ICMP_ECHO)
+		if (pctx->th_dep.icmp.type == ICMP_ECHO)
 			goto done;
 
 		type = ICMP_ECHO;
-		if (ctx->pctx.th_dep.icmp.type)
+		if (pctx->th_dep.icmp.type)
 			goto bad_proto;
 
 		stmt = __payload_gen_icmp_echo_dependency(ctx, expr,
@@ -1259,21 +1271,21 @@ int payload_gen_icmp_dependency(struct eval_ctx *ctx, const struct expr *expr,
 	case PROTO_ICMP_MTU:
 	case PROTO_ICMP_ADDRESS:
 		type = icmp_dep_to_type(tmpl->icmp_dep);
-		if (ctx->pctx.th_dep.icmp.type == type)
+		if (pctx->th_dep.icmp.type == type)
 			goto done;
-		if (ctx->pctx.th_dep.icmp.type)
+		if (pctx->th_dep.icmp.type)
 			goto bad_proto;
 		stmt = __payload_gen_icmp_simple_dependency(ctx, expr,
 							    &icmp_type_type,
 							    desc, type);
 		break;
 	case PROTO_ICMP6_ECHO:
-		if (ctx->pctx.th_dep.icmp.type == ICMP6_ECHO_REQUEST ||
-		    ctx->pctx.th_dep.icmp.type == ICMP6_ECHO_REPLY)
+		if (pctx->th_dep.icmp.type == ICMP6_ECHO_REQUEST ||
+		    pctx->th_dep.icmp.type == ICMP6_ECHO_REPLY)
 			goto done;
 
 		type = ICMP6_ECHO_REQUEST;
-		if (ctx->pctx.th_dep.icmp.type)
+		if (pctx->th_dep.icmp.type)
 			goto bad_proto;
 
 		stmt = __payload_gen_icmp_echo_dependency(ctx, expr,
@@ -1286,9 +1298,9 @@ int payload_gen_icmp_dependency(struct eval_ctx *ctx, const struct expr *expr,
 	case PROTO_ICMP6_MGMQ:
 	case PROTO_ICMP6_PPTR:
 		type = icmp_dep_to_type(tmpl->icmp_dep);
-		if (ctx->pctx.th_dep.icmp.type == type)
+		if (pctx->th_dep.icmp.type == type)
 			goto done;
-		if (ctx->pctx.th_dep.icmp.type)
+		if (pctx->th_dep.icmp.type)
 			goto bad_proto;
 		stmt = __payload_gen_icmp_simple_dependency(ctx, expr,
 							    &icmp6_type_type,
@@ -1299,7 +1311,7 @@ int payload_gen_icmp_dependency(struct eval_ctx *ctx, const struct expr *expr,
 		BUG("Unhandled icmp dependency code");
 	}
 
-	ctx->pctx.th_dep.icmp.type = type;
+	pctx->th_dep.icmp.type = type;
 
 	if (stmt_evaluate(ctx, stmt) < 0)
 		return expr_error(ctx->msgs, expr,
@@ -1310,5 +1322,5 @@ done:
 
 bad_proto:
 	return expr_error(ctx->msgs, expr, "incompatible icmp match: rule has %d, need %u",
-			  ctx->pctx.th_dep.icmp.type, type);
+			  pctx->th_dep.icmp.type, type);
 }