246 lines
7.1 KiB
Diff
246 lines
7.1 KiB
Diff
From 5f1676ac9f1aeb36d7695c3c354dade013a1e4f3 Mon Sep 17 00:00:00 2001
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From: Pablo Neira Ayuso <pablo@netfilter.org>
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Date: Tue, 18 Jul 2023 23:10:01 +0200
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Subject: [PATCH] meta: stash context statement length when generating
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payload/meta dependency
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... meta mark set ip dscp
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generates an implicit dependency from the inet family to match on meta
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nfproto ip.
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The length of this implicit expression is incorrectly adjusted to the
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statement length, ie. relational to compare meta nfproto takes 4 bytes
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instead of 1 byte. The evaluation of 'ip dscp' under the meta mark
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statement triggers this implicit dependency which should not consider
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the context statement length since it is added before the statement
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itself.
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This problem shows when listing the ruleset, since netlink_parse_cmp()
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where left->len < right->len, hence handling the implicit dependency as
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a concatenation, but it is actually a bug in the evaluation step that
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leads to incorrect bytecode.
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Fixes: 3c64ea7995cb ("evaluate: honor statement length in integer evaluation")
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Fixes: edecd58755a8 ("evaluate: support shifts larger than the width of the left operand")
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Tested-by: Brian Davidson <davidson.brian@gmail.com>
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Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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---
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src/payload.c | 13 ++++++
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tests/py/inet/meta.t | 5 +++
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tests/py/inet/meta.t.json | 86 ++++++++++++++++++++++++++++++++++++
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tests/py/inet/meta.t.payload | 40 +++++++++++++++++
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4 files changed, 144 insertions(+)
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diff --git a/src/payload.c b/src/payload.c
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index f67b5407..7862745b 100644
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--- a/src/payload.c
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+++ b/src/payload.c
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@@ -409,6 +409,7 @@ static int payload_add_dependency(struct eval_ctx *ctx,
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const struct proto_hdr_template *tmpl;
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struct expr *dep, *left, *right;
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struct proto_ctx *pctx;
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+ unsigned int stmt_len;
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struct stmt *stmt;
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int protocol;
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@@ -429,11 +430,16 @@ static int payload_add_dependency(struct eval_ctx *ctx,
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constant_data_ptr(protocol, tmpl->len));
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dep = relational_expr_alloc(&expr->location, OP_EQ, left, right);
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+
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+ stmt_len = ctx->stmt_len;
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+ ctx->stmt_len = 0;
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+
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stmt = expr_stmt_alloc(&dep->location, dep);
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if (stmt_evaluate(ctx, stmt) < 0) {
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return expr_error(ctx->msgs, expr,
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"dependency statement is invalid");
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}
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+ ctx->stmt_len = stmt_len;
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if (ctx->inner_desc) {
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if (tmpl->meta_key)
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@@ -543,6 +549,7 @@ int payload_gen_dependency(struct eval_ctx *ctx, const struct expr *expr,
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const struct hook_proto_desc *h;
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const struct proto_desc *desc;
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struct proto_ctx *pctx;
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+ unsigned int stmt_len;
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struct stmt *stmt;
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uint16_t type;
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@@ -559,12 +566,18 @@ int payload_gen_dependency(struct eval_ctx *ctx, const struct expr *expr,
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"protocol specification is invalid "
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"for this family");
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+ stmt_len = ctx->stmt_len;
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+ ctx->stmt_len = 0;
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+
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stmt = meta_stmt_meta_iiftype(&expr->location, type);
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if (stmt_evaluate(ctx, stmt) < 0) {
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return expr_error(ctx->msgs, expr,
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"dependency statement is invalid");
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}
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*res = stmt;
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+
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+ ctx->stmt_len = stmt_len;
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+
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return 0;
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}
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diff --git a/tests/py/inet/meta.t b/tests/py/inet/meta.t
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index 374738a7..5c062b39 100644
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--- a/tests/py/inet/meta.t
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+++ b/tests/py/inet/meta.t
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@@ -25,3 +25,8 @@ meta mark set ct mark >> 8;ok
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meta mark . tcp dport { 0x0000000a-0x00000014 . 80-90, 0x00100000-0x00100123 . 100-120 };ok
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ip saddr . meta mark { 1.2.3.4 . 0x00000100 , 1.2.3.6-1.2.3.8 . 0x00000200-0x00000300 };ok
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ip saddr . meta mark { 1.2.3.4 . 0x00000100 , 5.6.7.8 . 0x00000200 };ok
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+
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+meta mark set ip dscp;ok
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+meta mark set ip dscp | 0x40;ok
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+meta mark set ip6 dscp;ok
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+meta mark set ip6 dscp | 0x40;ok
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diff --git a/tests/py/inet/meta.t.json b/tests/py/inet/meta.t.json
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index 92a1f9bf..3ba0fd1d 100644
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--- a/tests/py/inet/meta.t.json
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+++ b/tests/py/inet/meta.t.json
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@@ -440,3 +440,89 @@
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}
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]
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+# meta mark set ip dscp
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+[
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+ {
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+ "mangle": {
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+ "key": {
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+ "meta": {
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+ "key": "mark"
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+ }
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+ },
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+ "value": {
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+ "payload": {
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+ "field": "dscp",
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+ "protocol": "ip"
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+ }
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+ }
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+ }
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+ }
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+]
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+
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+# meta mark set ip dscp | 0x40
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+[
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+ {
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+ "mangle": {
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+ "key": {
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+ "meta": {
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+ "key": "mark"
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+ }
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+ },
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+ "value": {
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+ "|": [
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+ {
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+ "payload": {
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+ "field": "dscp",
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+ "protocol": "ip"
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+ }
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+ },
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+ 64
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+ ]
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+ }
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+ }
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+ }
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+]
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+
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+# meta mark set ip6 dscp
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+[
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+ {
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+ "mangle": {
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+ "key": {
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+ "meta": {
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+ "key": "mark"
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+ }
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+ },
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+ "value": {
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+ "payload": {
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+ "field": "dscp",
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+ "protocol": "ip6"
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+ }
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+ }
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+ }
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+ }
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+]
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+
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+# meta mark set ip6 dscp | 0x40
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+[
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+ {
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+ "mangle": {
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+ "key": {
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+ "meta": {
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+ "key": "mark"
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+ }
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+ },
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+ "value": {
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+ "|": [
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+ {
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+ "payload": {
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+ "field": "dscp",
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+ "protocol": "ip6"
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+ }
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+ },
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+ 64
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+ ]
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+ }
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+ }
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+ }
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+]
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+
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diff --git a/tests/py/inet/meta.t.payload b/tests/py/inet/meta.t.payload
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index ea540907..c53b5077 100644
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--- a/tests/py/inet/meta.t.payload
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+++ b/tests/py/inet/meta.t.payload
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@@ -133,3 +133,43 @@ inet test-inet input
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[ meta load mark => reg 9 ]
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[ lookup reg 1 set __set%d ]
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+# meta mark set ip dscp
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+inet test-inet input
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+ [ meta load nfproto => reg 1 ]
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+ [ cmp eq reg 1 0x00000002 ]
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+ [ payload load 1b @ network header + 1 => reg 1 ]
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+ [ bitwise reg 1 = ( reg 1 & 0x000000fc ) ^ 0x00000000 ]
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+ [ bitwise reg 1 = ( reg 1 >> 0x00000002 ) ]
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+ [ meta set mark with reg 1 ]
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+
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+# meta mark set ip dscp | 0x40
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+inet test-inet input
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+ [ meta load nfproto => reg 1 ]
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+ [ cmp eq reg 1 0x00000002 ]
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+ [ payload load 1b @ network header + 1 => reg 1 ]
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+ [ bitwise reg 1 = ( reg 1 & 0x000000fc ) ^ 0x00000000 ]
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+ [ bitwise reg 1 = ( reg 1 >> 0x00000002 ) ]
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+ [ bitwise reg 1 = ( reg 1 & 0xffffffbf ) ^ 0x00000040 ]
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+ [ meta set mark with reg 1 ]
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+
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+# meta mark set ip6 dscp
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+inet test-inet input
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+ [ meta load nfproto => reg 1 ]
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+ [ cmp eq reg 1 0x0000000a ]
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+ [ payload load 2b @ network header + 0 => reg 1 ]
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+ [ bitwise reg 1 = ( reg 1 & 0x0000c00f ) ^ 0x00000000 ]
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+ [ byteorder reg 1 = ntoh(reg 1, 2, 2) ]
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+ [ bitwise reg 1 = ( reg 1 >> 0x00000006 ) ]
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+ [ meta set mark with reg 1 ]
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+
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+# meta mark set ip6 dscp | 0x40
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+inet test-inet input
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+ [ meta load nfproto => reg 1 ]
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+ [ cmp eq reg 1 0x0000000a ]
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+ [ payload load 2b @ network header + 0 => reg 1 ]
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+ [ bitwise reg 1 = ( reg 1 & 0x0000c00f ) ^ 0x00000000 ]
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+ [ byteorder reg 1 = ntoh(reg 1, 2, 2) ]
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+ [ bitwise reg 1 = ( reg 1 >> 0x00000006 ) ]
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+ [ bitwise reg 1 = ( reg 1 & 0xffffffbf ) ^ 0x00000040 ]
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+ [ meta set mark with reg 1 ]
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+
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