From dcae42a1c0095743ae3c2645f5b363885924a5b7 Mon Sep 17 00:00:00 2001
From: Thomas Calvert <49273329+thomascalvert-xlnx@users.noreply.github.com>
Date: Thu, 29 Feb 2024 13:36:39 +0000
Subject: [PATCH] backends/tc: Fix issues reported in #4327 (#4484)

* tc: Fix ingress pipeline not restoring header pointer from metadata.

Issue reported in #4327.

* tc: Fix lookahead not restoring offsetVar.

Issue reported in #4327.

* Update p4tc golden outputs.
---
 backends/ebpf/ebpfParser.h                    |  2 +-
 backends/tc/ebpfCodeGen.cpp                   | 32 +++++++++++++++++++
 backends/tc/ebpfCodeGen.h                     |  1 +
 .../calculator_control_blocks.c               |  1 +
 .../p4tc_samples_outputs/calculator_parser.c  |  6 ++++
 .../checksum_control_blocks.c                 |  1 +
 .../const_entries_range_mask_control_blocks.c |  1 +
 .../default_action_example_control_blocks.c   |  1 +
 ...ault_action_with_param_01_control_blocks.c |  1 +
 ...default_action_with_param_control_blocks.c |  1 +
 ...default_hit_const_example_control_blocks.c |  1 +
 .../drop_packet_example_control_blocks.c      |  1 +
 .../global_action_example_01_control_blocks.c |  1 +
 .../global_action_example_02_control_blocks.c |  1 +
 .../hash1_control_blocks.c                    |  1 +
 .../ipip_control_blocks.c                     |  1 +
 .../matchtype_control_blocks.c                |  1 +
 .../mix_matchtype_example_control_blocks.c    |  1 +
 ...ultiple_tables_example_01_control_blocks.c |  1 +
 ...ultiple_tables_example_02_control_blocks.c |  1 +
 .../name_annotation_example_control_blocks.c  |  1 +
 .../no_table_example_control_blocks.c         |  1 +
 .../noaction_example_01_control_blocks.c      |  1 +
 .../noaction_example_02_control_blocks.c      |  1 +
 ...ummask_annotation_example_control_blocks.c |  1 +
 .../send_to_port_example_control_blocks.c     |  1 +
 .../set_entry_timer_example_control_blocks.c  |  1 +
 .../simple_exact_example_control_blocks.c     |  1 +
 .../simple_lpm_example_control_blocks.c       |  1 +
 .../simple_ternary_example_control_blocks.c   |  1 +
 .../size_param_example_control_blocks.c       |  1 +
 ...c_type_annotation_example_control_blocks.c |  1 +
 .../test_ipv6_example_control_blocks.c        |  1 +
 33 files changed, 69 insertions(+), 1 deletion(-)

diff --git a/backends/ebpf/ebpfParser.h b/backends/ebpf/ebpfParser.h
index 5c0952a9257..4ca45d5deb6 100644
--- a/backends/ebpf/ebpfParser.h
+++ b/backends/ebpf/ebpfParser.h
@@ -39,7 +39,7 @@ class StateTranslationVisitor : public CodeGenInspector {
     virtual void compileExtractField(const IR::Expression *expr, const IR::StructField *field,
                                      unsigned hdrOffsetBits, EBPFType *type);
     virtual void compileExtract(const IR::Expression *destination);
-    void compileLookahead(const IR::Expression *destination);
+    virtual void compileLookahead(const IR::Expression *destination);
     void compileAdvance(const P4::ExternMethod *ext);
     void compileVerify(const IR::MethodCallExpression *expression);
 
diff --git a/backends/tc/ebpfCodeGen.cpp b/backends/tc/ebpfCodeGen.cpp
index 51867161222..830d4a8246f 100644
--- a/backends/tc/ebpfCodeGen.cpp
+++ b/backends/tc/ebpfCodeGen.cpp
@@ -268,6 +268,10 @@ void TCIngressPipelinePNA::emit(EBPF::CodeBuilder *builder) {
         builder->newline();
         builder->emitIndent();
         builder->appendFormat("unsigned %s = hdrMd->%s;", offsetVar.c_str(), offsetVar.c_str());
+        builder->newline();
+        builder->emitIndent();
+        builder->appendFormat("%s = %s + BYTES(%s);", headerStartVar.c_str(),
+                              packetStartVar.c_str(), offsetVar.c_str());
     }
     builder->newline();
     emitHeadersFromCPUMAP(builder);
@@ -705,6 +709,34 @@ void PnaStateTranslationVisitor::compileExtractField(const IR::Expression *expr,
     builder->newline();
 }
 
+void PnaStateTranslationVisitor::compileLookahead(const IR::Expression *destination) {
+    cstring msgStr = Util::printf_format("Parser: lookahead for %s %s",
+                                         state->parser->typeMap->getType(destination)->toString(),
+                                         destination->toString());
+    builder->target->emitTraceMessage(builder, msgStr.c_str());
+
+    builder->emitIndent();
+    builder->blockStart();
+    builder->emitIndent();
+    builder->appendFormat("u8* %s_save = %s", state->parser->program->headerStartVar.c_str(),
+                          state->parser->program->headerStartVar.c_str());
+    builder->endOfStatement(true);
+    builder->emitIndent();
+    builder->appendFormat("unsigned %s_save = %s", state->parser->program->offsetVar.c_str(),
+                          state->parser->program->offsetVar.c_str());
+    builder->endOfStatement(true);
+    compileExtract(destination);
+    builder->emitIndent();
+    builder->appendFormat("%s = %s_save", state->parser->program->headerStartVar.c_str(),
+                          state->parser->program->headerStartVar.c_str());
+    builder->endOfStatement(true);
+    builder->emitIndent();
+    builder->appendFormat("%s = %s_save", state->parser->program->offsetVar.c_str(),
+                          state->parser->program->offsetVar.c_str());
+    builder->endOfStatement(true);
+    builder->blockEnd(true);
+}
+
 // =====================EBPFTablePNA=============================
 void EBPFTablePNA::emitKeyType(EBPF::CodeBuilder *builder) {
     builder->emitIndent();
diff --git a/backends/tc/ebpfCodeGen.h b/backends/tc/ebpfCodeGen.h
index 633a6121c07..1d5786a7467 100644
--- a/backends/tc/ebpfCodeGen.h
+++ b/backends/tc/ebpfCodeGen.h
@@ -121,6 +121,7 @@ class PnaStateTranslationVisitor : public EBPF::PsaStateTranslationVisitor {
  protected:
     void compileExtractField(const IR::Expression *expr, const IR::StructField *field,
                              unsigned hdrOffsetBits, EBPF::EBPFType *type) override;
+    void compileLookahead(const IR::Expression *destination) override;
 };
 
 class EBPFPnaParser : public EBPF::EBPFPsaParser {
diff --git a/testdata/p4tc_samples_outputs/calculator_control_blocks.c b/testdata/p4tc_samples_outputs/calculator_control_blocks.c
index ec01e4ce737..f6b4c710f8c 100644
--- a/testdata/p4tc_samples_outputs/calculator_control_blocks.c
+++ b/testdata/p4tc_samples_outputs/calculator_control_blocks.c
@@ -56,6 +56,7 @@ static __always_inline int process(struct __sk_buff *skb, struct headers_t *hdr,
     if (!hdrMd)
         return TC_ACT_SHOT;
     unsigned ebpf_packetOffsetInBits = hdrMd->ebpf_packetOffsetInBits;
+    hdr_start = pkt + BYTES(ebpf_packetOffsetInBits);
     hdr = &(hdrMd->cpumap_hdr);
     meta = &(hdrMd->cpumap_usermeta);
 {
diff --git a/testdata/p4tc_samples_outputs/calculator_parser.c b/testdata/p4tc_samples_outputs/calculator_parser.c
index 33044da36b6..a9623807c5c 100644
--- a/testdata/p4tc_samples_outputs/calculator_parser.c
+++ b/testdata/p4tc_samples_outputs/calculator_parser.c
@@ -34,6 +34,7 @@ static __always_inline int run_parser(struct __sk_buff *skb, struct headers_t *h
         check_p4calc: {
             {
                 u8* hdr_start_save = hdr_start;
+                unsigned ebpf_packetOffsetInBits_save = ebpf_packetOffsetInBits;
                 if ((u8*)ebpf_packetEnd < hdr_start + BYTES(128 + 0)) {
                     ebpf_errorCode = PacketTooShort;
                     goto reject;
@@ -65,9 +66,11 @@ static __always_inline int run_parser(struct __sk_buff *skb, struct headers_t *h
                 hdr_start += BYTES(128);
 
                 hdr_start = hdr_start_save;
+                ebpf_packetOffsetInBits = ebpf_packetOffsetInBits_save;
             }
             {
                 u8* hdr_start_save = hdr_start;
+                unsigned ebpf_packetOffsetInBits_save = ebpf_packetOffsetInBits;
                 if ((u8*)ebpf_packetEnd < hdr_start + BYTES(128 + 0)) {
                     ebpf_errorCode = PacketTooShort;
                     goto reject;
@@ -99,9 +102,11 @@ static __always_inline int run_parser(struct __sk_buff *skb, struct headers_t *h
                 hdr_start += BYTES(128);
 
                 hdr_start = hdr_start_save;
+                ebpf_packetOffsetInBits = ebpf_packetOffsetInBits_save;
             }
             {
                 u8* hdr_start_save = hdr_start;
+                unsigned ebpf_packetOffsetInBits_save = ebpf_packetOffsetInBits;
                 if ((u8*)ebpf_packetEnd < hdr_start + BYTES(128 + 0)) {
                     ebpf_errorCode = PacketTooShort;
                     goto reject;
@@ -133,6 +138,7 @@ static __always_inline int run_parser(struct __sk_buff *skb, struct headers_t *h
                 hdr_start += BYTES(128);
 
                 hdr_start = hdr_start_save;
+                ebpf_packetOffsetInBits = ebpf_packetOffsetInBits_save;
             }
             u32 select_0;
             select_0 = (((((u32)(((u16)tmp_0.p << 8) | ((u16)tmp_2.four & 0xff)) << 8) & ((1 << 24) - 1)) | (((u32)tmp_4.ver & 0xff) & ((1 << 24) - 1))) & ((1 << 24) - 1));
diff --git a/testdata/p4tc_samples_outputs/checksum_control_blocks.c b/testdata/p4tc_samples_outputs/checksum_control_blocks.c
index 648b91dbf4b..f7bf2be6257 100644
--- a/testdata/p4tc_samples_outputs/checksum_control_blocks.c
+++ b/testdata/p4tc_samples_outputs/checksum_control_blocks.c
@@ -47,6 +47,7 @@ static __always_inline int process(struct __sk_buff *skb, struct my_ingress_head
     if (!hdrMd)
         return TC_ACT_SHOT;
     unsigned ebpf_packetOffsetInBits = hdrMd->ebpf_packetOffsetInBits;
+    hdr_start = pkt + BYTES(ebpf_packetOffsetInBits);
     hdr = &(hdrMd->cpumap_hdr);
     meta = &(hdrMd->cpumap_usermeta);
 {
diff --git a/testdata/p4tc_samples_outputs/const_entries_range_mask_control_blocks.c b/testdata/p4tc_samples_outputs/const_entries_range_mask_control_blocks.c
index a75cb96c001..e4e92178eb5 100644
--- a/testdata/p4tc_samples_outputs/const_entries_range_mask_control_blocks.c
+++ b/testdata/p4tc_samples_outputs/const_entries_range_mask_control_blocks.c
@@ -45,6 +45,7 @@ static __always_inline int process(struct __sk_buff *skb, struct Header_t *h, st
     if (!hdrMd)
         return TC_ACT_SHOT;
     unsigned ebpf_packetOffsetInBits = hdrMd->ebpf_packetOffsetInBits;
+    hdr_start = pkt + BYTES(ebpf_packetOffsetInBits);
     h = &(hdrMd->cpumap_hdr);
     m = &(hdrMd->cpumap_usermeta);
 {
diff --git a/testdata/p4tc_samples_outputs/default_action_example_control_blocks.c b/testdata/p4tc_samples_outputs/default_action_example_control_blocks.c
index e856bfcea05..db36a1f74f2 100644
--- a/testdata/p4tc_samples_outputs/default_action_example_control_blocks.c
+++ b/testdata/p4tc_samples_outputs/default_action_example_control_blocks.c
@@ -68,6 +68,7 @@ static __always_inline int process(struct __sk_buff *skb, struct headers_t *hdr,
     if (!hdrMd)
         return TC_ACT_SHOT;
     unsigned ebpf_packetOffsetInBits = hdrMd->ebpf_packetOffsetInBits;
+    hdr_start = pkt + BYTES(ebpf_packetOffsetInBits);
     hdr = &(hdrMd->cpumap_hdr);
     user_meta = &(hdrMd->cpumap_usermeta);
 {
diff --git a/testdata/p4tc_samples_outputs/default_action_with_param_01_control_blocks.c b/testdata/p4tc_samples_outputs/default_action_with_param_01_control_blocks.c
index 3f339eaf937..ec49d583490 100644
--- a/testdata/p4tc_samples_outputs/default_action_with_param_01_control_blocks.c
+++ b/testdata/p4tc_samples_outputs/default_action_with_param_01_control_blocks.c
@@ -66,6 +66,7 @@ static __always_inline int process(struct __sk_buff *skb, struct headers_t *hdr,
     if (!hdrMd)
         return TC_ACT_SHOT;
     unsigned ebpf_packetOffsetInBits = hdrMd->ebpf_packetOffsetInBits;
+    hdr_start = pkt + BYTES(ebpf_packetOffsetInBits);
     hdr = &(hdrMd->cpumap_hdr);
     user_meta = &(hdrMd->cpumap_usermeta);
 {
diff --git a/testdata/p4tc_samples_outputs/default_action_with_param_control_blocks.c b/testdata/p4tc_samples_outputs/default_action_with_param_control_blocks.c
index 41a3afb8601..22d8dba79de 100644
--- a/testdata/p4tc_samples_outputs/default_action_with_param_control_blocks.c
+++ b/testdata/p4tc_samples_outputs/default_action_with_param_control_blocks.c
@@ -68,6 +68,7 @@ static __always_inline int process(struct __sk_buff *skb, struct headers_t *hdr,
     if (!hdrMd)
         return TC_ACT_SHOT;
     unsigned ebpf_packetOffsetInBits = hdrMd->ebpf_packetOffsetInBits;
+    hdr_start = pkt + BYTES(ebpf_packetOffsetInBits);
     hdr = &(hdrMd->cpumap_hdr);
     user_meta = &(hdrMd->cpumap_usermeta);
 {
diff --git a/testdata/p4tc_samples_outputs/default_hit_const_example_control_blocks.c b/testdata/p4tc_samples_outputs/default_hit_const_example_control_blocks.c
index ec132972c01..030749a7586 100644
--- a/testdata/p4tc_samples_outputs/default_hit_const_example_control_blocks.c
+++ b/testdata/p4tc_samples_outputs/default_hit_const_example_control_blocks.c
@@ -52,6 +52,7 @@ static __always_inline int process(struct __sk_buff *skb, struct headers_t *hdr,
     if (!hdrMd)
         return TC_ACT_SHOT;
     unsigned ebpf_packetOffsetInBits = hdrMd->ebpf_packetOffsetInBits;
+    hdr_start = pkt + BYTES(ebpf_packetOffsetInBits);
     hdr = &(hdrMd->cpumap_hdr);
     meta = &(hdrMd->cpumap_usermeta);
 {
diff --git a/testdata/p4tc_samples_outputs/drop_packet_example_control_blocks.c b/testdata/p4tc_samples_outputs/drop_packet_example_control_blocks.c
index a19dbd4a575..7982640a80a 100644
--- a/testdata/p4tc_samples_outputs/drop_packet_example_control_blocks.c
+++ b/testdata/p4tc_samples_outputs/drop_packet_example_control_blocks.c
@@ -45,6 +45,7 @@ static __always_inline int process(struct __sk_buff *skb, struct headers_t *hdr,
     if (!hdrMd)
         return TC_ACT_SHOT;
     unsigned ebpf_packetOffsetInBits = hdrMd->ebpf_packetOffsetInBits;
+    hdr_start = pkt + BYTES(ebpf_packetOffsetInBits);
     hdr = &(hdrMd->cpumap_hdr);
     user_meta = &(hdrMd->cpumap_usermeta);
 {
diff --git a/testdata/p4tc_samples_outputs/global_action_example_01_control_blocks.c b/testdata/p4tc_samples_outputs/global_action_example_01_control_blocks.c
index daace3c16c4..ba344055f17 100644
--- a/testdata/p4tc_samples_outputs/global_action_example_01_control_blocks.c
+++ b/testdata/p4tc_samples_outputs/global_action_example_01_control_blocks.c
@@ -68,6 +68,7 @@ static __always_inline int process(struct __sk_buff *skb, struct my_ingress_head
     if (!hdrMd)
         return TC_ACT_SHOT;
     unsigned ebpf_packetOffsetInBits = hdrMd->ebpf_packetOffsetInBits;
+    hdr_start = pkt + BYTES(ebpf_packetOffsetInBits);
     hdr = &(hdrMd->cpumap_hdr);
     meta = &(hdrMd->cpumap_usermeta);
 {
diff --git a/testdata/p4tc_samples_outputs/global_action_example_02_control_blocks.c b/testdata/p4tc_samples_outputs/global_action_example_02_control_blocks.c
index b5a3932293c..ac79caa03dc 100644
--- a/testdata/p4tc_samples_outputs/global_action_example_02_control_blocks.c
+++ b/testdata/p4tc_samples_outputs/global_action_example_02_control_blocks.c
@@ -69,6 +69,7 @@ static __always_inline int process(struct __sk_buff *skb, struct my_ingress_head
     if (!hdrMd)
         return TC_ACT_SHOT;
     unsigned ebpf_packetOffsetInBits = hdrMd->ebpf_packetOffsetInBits;
+    hdr_start = pkt + BYTES(ebpf_packetOffsetInBits);
     hdr = &(hdrMd->cpumap_hdr);
     meta = &(hdrMd->cpumap_usermeta);
 {
diff --git a/testdata/p4tc_samples_outputs/hash1_control_blocks.c b/testdata/p4tc_samples_outputs/hash1_control_blocks.c
index b03d47f1780..06cda69cbcc 100644
--- a/testdata/p4tc_samples_outputs/hash1_control_blocks.c
+++ b/testdata/p4tc_samples_outputs/hash1_control_blocks.c
@@ -25,6 +25,7 @@ static __always_inline int process(struct __sk_buff *skb, struct my_ingress_head
     if (!hdrMd)
         return TC_ACT_SHOT;
     unsigned ebpf_packetOffsetInBits = hdrMd->ebpf_packetOffsetInBits;
+    hdr_start = pkt + BYTES(ebpf_packetOffsetInBits);
     hdr = &(hdrMd->cpumap_hdr);
     meta = &(hdrMd->cpumap_usermeta);
 {
diff --git a/testdata/p4tc_samples_outputs/ipip_control_blocks.c b/testdata/p4tc_samples_outputs/ipip_control_blocks.c
index 518bc78a403..6f0474f07b6 100644
--- a/testdata/p4tc_samples_outputs/ipip_control_blocks.c
+++ b/testdata/p4tc_samples_outputs/ipip_control_blocks.c
@@ -52,6 +52,7 @@ static __always_inline int process(struct __sk_buff *skb, struct headers_t *hdr,
     if (!hdrMd)
         return TC_ACT_SHOT;
     unsigned ebpf_packetOffsetInBits = hdrMd->ebpf_packetOffsetInBits;
+    hdr_start = pkt + BYTES(ebpf_packetOffsetInBits);
     hdr = &(hdrMd->cpumap_hdr);
     meta = &(hdrMd->cpumap_usermeta);
 {
diff --git a/testdata/p4tc_samples_outputs/matchtype_control_blocks.c b/testdata/p4tc_samples_outputs/matchtype_control_blocks.c
index e892f5fd596..8c9394cb148 100644
--- a/testdata/p4tc_samples_outputs/matchtype_control_blocks.c
+++ b/testdata/p4tc_samples_outputs/matchtype_control_blocks.c
@@ -114,6 +114,7 @@ static __always_inline int process(struct __sk_buff *skb, struct headers_t *hdr,
     if (!hdrMd)
         return TC_ACT_SHOT;
     unsigned ebpf_packetOffsetInBits = hdrMd->ebpf_packetOffsetInBits;
+    hdr_start = pkt + BYTES(ebpf_packetOffsetInBits);
     hdr = &(hdrMd->cpumap_hdr);
     user_meta = &(hdrMd->cpumap_usermeta);
 {
diff --git a/testdata/p4tc_samples_outputs/mix_matchtype_example_control_blocks.c b/testdata/p4tc_samples_outputs/mix_matchtype_example_control_blocks.c
index 45948a137bb..8753274d468 100644
--- a/testdata/p4tc_samples_outputs/mix_matchtype_example_control_blocks.c
+++ b/testdata/p4tc_samples_outputs/mix_matchtype_example_control_blocks.c
@@ -120,6 +120,7 @@ static __always_inline int process(struct __sk_buff *skb, struct headers_t *hdr,
     if (!hdrMd)
         return TC_ACT_SHOT;
     unsigned ebpf_packetOffsetInBits = hdrMd->ebpf_packetOffsetInBits;
+    hdr_start = pkt + BYTES(ebpf_packetOffsetInBits);
     hdr = &(hdrMd->cpumap_hdr);
     user_meta = &(hdrMd->cpumap_usermeta);
 {
diff --git a/testdata/p4tc_samples_outputs/multiple_tables_example_01_control_blocks.c b/testdata/p4tc_samples_outputs/multiple_tables_example_01_control_blocks.c
index 605663081ef..152e489e7a7 100644
--- a/testdata/p4tc_samples_outputs/multiple_tables_example_01_control_blocks.c
+++ b/testdata/p4tc_samples_outputs/multiple_tables_example_01_control_blocks.c
@@ -190,6 +190,7 @@ static __always_inline int process(struct __sk_buff *skb, struct headers_t *hdr,
     if (!hdrMd)
         return TC_ACT_SHOT;
     unsigned ebpf_packetOffsetInBits = hdrMd->ebpf_packetOffsetInBits;
+    hdr_start = pkt + BYTES(ebpf_packetOffsetInBits);
     hdr = &(hdrMd->cpumap_hdr);
     user_meta = &(hdrMd->cpumap_usermeta);
 {
diff --git a/testdata/p4tc_samples_outputs/multiple_tables_example_02_control_blocks.c b/testdata/p4tc_samples_outputs/multiple_tables_example_02_control_blocks.c
index cec853677a4..e85f1b94f21 100644
--- a/testdata/p4tc_samples_outputs/multiple_tables_example_02_control_blocks.c
+++ b/testdata/p4tc_samples_outputs/multiple_tables_example_02_control_blocks.c
@@ -187,6 +187,7 @@ static __always_inline int process(struct __sk_buff *skb, struct headers_t *hdr,
     if (!hdrMd)
         return TC_ACT_SHOT;
     unsigned ebpf_packetOffsetInBits = hdrMd->ebpf_packetOffsetInBits;
+    hdr_start = pkt + BYTES(ebpf_packetOffsetInBits);
     hdr = &(hdrMd->cpumap_hdr);
     user_meta = &(hdrMd->cpumap_usermeta);
 {
diff --git a/testdata/p4tc_samples_outputs/name_annotation_example_control_blocks.c b/testdata/p4tc_samples_outputs/name_annotation_example_control_blocks.c
index 44f7250bdbb..05aa35446a5 100644
--- a/testdata/p4tc_samples_outputs/name_annotation_example_control_blocks.c
+++ b/testdata/p4tc_samples_outputs/name_annotation_example_control_blocks.c
@@ -67,6 +67,7 @@ static __always_inline int process(struct __sk_buff *skb, struct headers_t *hdr,
     if (!hdrMd)
         return TC_ACT_SHOT;
     unsigned ebpf_packetOffsetInBits = hdrMd->ebpf_packetOffsetInBits;
+    hdr_start = pkt + BYTES(ebpf_packetOffsetInBits);
     hdr = &(hdrMd->cpumap_hdr);
     user_meta = &(hdrMd->cpumap_usermeta);
 {
diff --git a/testdata/p4tc_samples_outputs/no_table_example_control_blocks.c b/testdata/p4tc_samples_outputs/no_table_example_control_blocks.c
index ce0ea5f04af..7f48768c9b9 100644
--- a/testdata/p4tc_samples_outputs/no_table_example_control_blocks.c
+++ b/testdata/p4tc_samples_outputs/no_table_example_control_blocks.c
@@ -25,6 +25,7 @@ static __always_inline int process(struct __sk_buff *skb, struct headers_t *hdr,
     if (!hdrMd)
         return TC_ACT_SHOT;
     unsigned ebpf_packetOffsetInBits = hdrMd->ebpf_packetOffsetInBits;
+    hdr_start = pkt + BYTES(ebpf_packetOffsetInBits);
     hdr = &(hdrMd->cpumap_hdr);
     user_meta = &(hdrMd->cpumap_usermeta);
 {
diff --git a/testdata/p4tc_samples_outputs/noaction_example_01_control_blocks.c b/testdata/p4tc_samples_outputs/noaction_example_01_control_blocks.c
index ebd01062783..b737dc8667b 100644
--- a/testdata/p4tc_samples_outputs/noaction_example_01_control_blocks.c
+++ b/testdata/p4tc_samples_outputs/noaction_example_01_control_blocks.c
@@ -67,6 +67,7 @@ static __always_inline int process(struct __sk_buff *skb, struct headers_t *hdr,
     if (!hdrMd)
         return TC_ACT_SHOT;
     unsigned ebpf_packetOffsetInBits = hdrMd->ebpf_packetOffsetInBits;
+    hdr_start = pkt + BYTES(ebpf_packetOffsetInBits);
     hdr = &(hdrMd->cpumap_hdr);
     user_meta = &(hdrMd->cpumap_usermeta);
 {
diff --git a/testdata/p4tc_samples_outputs/noaction_example_02_control_blocks.c b/testdata/p4tc_samples_outputs/noaction_example_02_control_blocks.c
index 272aaf83999..cf628fa093e 100644
--- a/testdata/p4tc_samples_outputs/noaction_example_02_control_blocks.c
+++ b/testdata/p4tc_samples_outputs/noaction_example_02_control_blocks.c
@@ -58,6 +58,7 @@ static __always_inline int process(struct __sk_buff *skb, struct headers_t *hdr,
     if (!hdrMd)
         return TC_ACT_SHOT;
     unsigned ebpf_packetOffsetInBits = hdrMd->ebpf_packetOffsetInBits;
+    hdr_start = pkt + BYTES(ebpf_packetOffsetInBits);
     hdr = &(hdrMd->cpumap_hdr);
     user_meta = &(hdrMd->cpumap_usermeta);
 {
diff --git a/testdata/p4tc_samples_outputs/nummask_annotation_example_control_blocks.c b/testdata/p4tc_samples_outputs/nummask_annotation_example_control_blocks.c
index 078922d5d0a..5a9cf8261ca 100644
--- a/testdata/p4tc_samples_outputs/nummask_annotation_example_control_blocks.c
+++ b/testdata/p4tc_samples_outputs/nummask_annotation_example_control_blocks.c
@@ -47,6 +47,7 @@ static __always_inline int process(struct __sk_buff *skb, struct headers_t *hdr,
     if (!hdrMd)
         return TC_ACT_SHOT;
     unsigned ebpf_packetOffsetInBits = hdrMd->ebpf_packetOffsetInBits;
+    hdr_start = pkt + BYTES(ebpf_packetOffsetInBits);
     hdr = &(hdrMd->cpumap_hdr);
     meta = &(hdrMd->cpumap_usermeta);
 {
diff --git a/testdata/p4tc_samples_outputs/send_to_port_example_control_blocks.c b/testdata/p4tc_samples_outputs/send_to_port_example_control_blocks.c
index cf55e82afac..a5a44ef048e 100644
--- a/testdata/p4tc_samples_outputs/send_to_port_example_control_blocks.c
+++ b/testdata/p4tc_samples_outputs/send_to_port_example_control_blocks.c
@@ -47,6 +47,7 @@ static __always_inline int process(struct __sk_buff *skb, struct headers_t *hdr,
     if (!hdrMd)
         return TC_ACT_SHOT;
     unsigned ebpf_packetOffsetInBits = hdrMd->ebpf_packetOffsetInBits;
+    hdr_start = pkt + BYTES(ebpf_packetOffsetInBits);
     hdr = &(hdrMd->cpumap_hdr);
     user_meta = &(hdrMd->cpumap_usermeta);
 {
diff --git a/testdata/p4tc_samples_outputs/set_entry_timer_example_control_blocks.c b/testdata/p4tc_samples_outputs/set_entry_timer_example_control_blocks.c
index 8225a54b07e..9799a406fce 100644
--- a/testdata/p4tc_samples_outputs/set_entry_timer_example_control_blocks.c
+++ b/testdata/p4tc_samples_outputs/set_entry_timer_example_control_blocks.c
@@ -66,6 +66,7 @@ static __always_inline int process(struct __sk_buff *skb, struct headers_t *hdr,
     if (!hdrMd)
         return TC_ACT_SHOT;
     unsigned ebpf_packetOffsetInBits = hdrMd->ebpf_packetOffsetInBits;
+    hdr_start = pkt + BYTES(ebpf_packetOffsetInBits);
     hdr = &(hdrMd->cpumap_hdr);
     user_meta = &(hdrMd->cpumap_usermeta);
 {
diff --git a/testdata/p4tc_samples_outputs/simple_exact_example_control_blocks.c b/testdata/p4tc_samples_outputs/simple_exact_example_control_blocks.c
index 11cab625ecd..91fb742ac0f 100644
--- a/testdata/p4tc_samples_outputs/simple_exact_example_control_blocks.c
+++ b/testdata/p4tc_samples_outputs/simple_exact_example_control_blocks.c
@@ -47,6 +47,7 @@ static __always_inline int process(struct __sk_buff *skb, struct my_ingress_head
     if (!hdrMd)
         return TC_ACT_SHOT;
     unsigned ebpf_packetOffsetInBits = hdrMd->ebpf_packetOffsetInBits;
+    hdr_start = pkt + BYTES(ebpf_packetOffsetInBits);
     hdr = &(hdrMd->cpumap_hdr);
     meta = &(hdrMd->cpumap_usermeta);
 {
diff --git a/testdata/p4tc_samples_outputs/simple_lpm_example_control_blocks.c b/testdata/p4tc_samples_outputs/simple_lpm_example_control_blocks.c
index 3b63078c4eb..446bbb8100a 100644
--- a/testdata/p4tc_samples_outputs/simple_lpm_example_control_blocks.c
+++ b/testdata/p4tc_samples_outputs/simple_lpm_example_control_blocks.c
@@ -47,6 +47,7 @@ static __always_inline int process(struct __sk_buff *skb, struct my_ingress_head
     if (!hdrMd)
         return TC_ACT_SHOT;
     unsigned ebpf_packetOffsetInBits = hdrMd->ebpf_packetOffsetInBits;
+    hdr_start = pkt + BYTES(ebpf_packetOffsetInBits);
     hdr = &(hdrMd->cpumap_hdr);
     meta = &(hdrMd->cpumap_usermeta);
 {
diff --git a/testdata/p4tc_samples_outputs/simple_ternary_example_control_blocks.c b/testdata/p4tc_samples_outputs/simple_ternary_example_control_blocks.c
index 2ad17283857..9e9c34f1926 100644
--- a/testdata/p4tc_samples_outputs/simple_ternary_example_control_blocks.c
+++ b/testdata/p4tc_samples_outputs/simple_ternary_example_control_blocks.c
@@ -53,6 +53,7 @@ static __always_inline int process(struct __sk_buff *skb, struct my_ingress_head
     if (!hdrMd)
         return TC_ACT_SHOT;
     unsigned ebpf_packetOffsetInBits = hdrMd->ebpf_packetOffsetInBits;
+    hdr_start = pkt + BYTES(ebpf_packetOffsetInBits);
     hdr = &(hdrMd->cpumap_hdr);
     meta = &(hdrMd->cpumap_usermeta);
 {
diff --git a/testdata/p4tc_samples_outputs/size_param_example_control_blocks.c b/testdata/p4tc_samples_outputs/size_param_example_control_blocks.c
index 0105a9e2923..af7755a2667 100644
--- a/testdata/p4tc_samples_outputs/size_param_example_control_blocks.c
+++ b/testdata/p4tc_samples_outputs/size_param_example_control_blocks.c
@@ -67,6 +67,7 @@ static __always_inline int process(struct __sk_buff *skb, struct headers_t *hdr,
     if (!hdrMd)
         return TC_ACT_SHOT;
     unsigned ebpf_packetOffsetInBits = hdrMd->ebpf_packetOffsetInBits;
+    hdr_start = pkt + BYTES(ebpf_packetOffsetInBits);
     hdr = &(hdrMd->cpumap_hdr);
     user_meta = &(hdrMd->cpumap_usermeta);
 {
diff --git a/testdata/p4tc_samples_outputs/tc_type_annotation_example_control_blocks.c b/testdata/p4tc_samples_outputs/tc_type_annotation_example_control_blocks.c
index 53832531e97..e673a5fa76d 100644
--- a/testdata/p4tc_samples_outputs/tc_type_annotation_example_control_blocks.c
+++ b/testdata/p4tc_samples_outputs/tc_type_annotation_example_control_blocks.c
@@ -59,6 +59,7 @@ static __always_inline int process(struct __sk_buff *skb, struct headers_t *hdr,
     if (!hdrMd)
         return TC_ACT_SHOT;
     unsigned ebpf_packetOffsetInBits = hdrMd->ebpf_packetOffsetInBits;
+    hdr_start = pkt + BYTES(ebpf_packetOffsetInBits);
     hdr = &(hdrMd->cpumap_hdr);
     user_meta = &(hdrMd->cpumap_usermeta);
 {
diff --git a/testdata/p4tc_samples_outputs/test_ipv6_example_control_blocks.c b/testdata/p4tc_samples_outputs/test_ipv6_example_control_blocks.c
index 6ea9752d0c1..9fc5798d242 100644
--- a/testdata/p4tc_samples_outputs/test_ipv6_example_control_blocks.c
+++ b/testdata/p4tc_samples_outputs/test_ipv6_example_control_blocks.c
@@ -42,6 +42,7 @@ static __always_inline int process(struct __sk_buff *skb, struct headers_t *hdr,
     if (!hdrMd)
         return TC_ACT_SHOT;
     unsigned ebpf_packetOffsetInBits = hdrMd->ebpf_packetOffsetInBits;
+    hdr_start = pkt + BYTES(ebpf_packetOffsetInBits);
     hdr = &(hdrMd->cpumap_hdr);
     user_meta = &(hdrMd->cpumap_usermeta);
 {