RRC/E1AP: Fix SDAP header mapping in E1AP and test callback header handling

This commit fixes two related issues:

1. SDAP Header Mapping Bug (cucp_cuup_handler.c):
   The original code incorrectly mapped SDAP header configuration from
   internal E1AP representation to ASN.1 enum values. The internal
   representation (`bearer_context_sdap_config_t`) uses true=present/false=absent,
   while ASN.1 enum (`E1AP_SDAP_Configuration_t`) uses
   0=present/1=absent. The fix correctly inverts the mapping:
   - Internal true (1) → ASN.1 0 (present)
   - Internal false (0) → ASN.1 1 (absent)

The commit also clarifies internal representation in the stack.

2. Test Overhead Adjustment (nr-cuup-load-test.c):
   The change in (1) led to a failure in nr_cuup_functional_test
   with assertion: "size % 4 == 0" in recv_ng()

   - Changed UL packet overhead from 3 bytes to 2 bytes in sender_thread()
   - Before the SDAP fix, the test incorrectly accounted for 3 bytes:
     * 2 bytes PDCP header (correct)
     * 1 byte SDAP header (incorrectly included)
   - After the SDAP fix, SDAP headers are correctly set to absent, so
     only 2 bytes (PDCP header) are needed

   This ensures the test sends packets with the correct header size,
   matching what CU-UP expects after the SDAP configuration fix.

The load test does not enable SDAP headers, therefore the original 3-byte
overhead was possibly a workaround for the SDAP header bug.
With the bug fixed, the test correctly uses 2-byte overhead (PDCP header).

openair2/COMMON/e1ap_messages_types.h

@@ -268,8 +268,8 @@ typedef struct up_params_s {
 /* IE SDAP Configuration (clause 9.3.1.39 of 3GPP TS 38.463) */
 typedef struct bearer_context_sdap_config_s {
   long defaultDRB;
-  long sDAP_Header_UL;
-  long sDAP_Header_DL;
+  bool sDAP_Header_UL;
+  bool sDAP_Header_DL;
 } bearer_context_sdap_config_t;
 
 /* IE PDCP Configuration (clause 9.3.1.38 of 3GPP TS 38.463) */

openair2/E1AP/lib/e1ap_bearer_context_management.c

@@ -192,8 +192,8 @@ static E1AP_SDAP_Configuration_t e1_encode_sdap_config(const bearer_context_sdap
 {
   E1AP_SDAP_Configuration_t out = {0};
   out.defaultDRB = in->defaultDRB ? E1AP_DefaultDRB_true : E1AP_DefaultDRB_false;
-  out.sDAP_Header_UL = in->sDAP_Header_UL;
-  out.sDAP_Header_DL = in->sDAP_Header_DL;
+  out.sDAP_Header_UL = in->sDAP_Header_UL ? E1AP_SDAP_Header_UL_present : E1AP_SDAP_Header_UL_absent;
+  out.sDAP_Header_DL = in->sDAP_Header_DL ? E1AP_SDAP_Header_DL_present : E1AP_SDAP_Header_DL_absent;
   return out;
 }
 
@@ -201,8 +201,8 @@ static E1AP_SDAP_Configuration_t e1_encode_sdap_config(const bearer_context_sdap
 static bool e1_decode_sdap_config(bearer_context_sdap_config_t *out, const E1AP_SDAP_Configuration_t *in)
 {
   out->defaultDRB = in->defaultDRB == E1AP_DefaultDRB_true;
-  out->sDAP_Header_UL = in->sDAP_Header_UL;
-  out->sDAP_Header_DL = in->sDAP_Header_DL;
+  out->sDAP_Header_UL = in->sDAP_Header_UL == E1AP_SDAP_Header_UL_present;
+  out->sDAP_Header_DL = in->sDAP_Header_DL == E1AP_SDAP_Header_DL_present;
   return true;
 }
 
@@ -212,8 +212,8 @@ static bool e1_decode_sdap_config(bearer_context_sdap_config_t *out, const E1AP_
 static bool eq_sdap_config(const bearer_context_sdap_config_t *a, const bearer_context_sdap_config_t *b)
 {
   _E1_EQ_CHECK_LONG(a->defaultDRB, b->defaultDRB);
-  _E1_EQ_CHECK_LONG(a->sDAP_Header_UL, b->sDAP_Header_UL);
-  _E1_EQ_CHECK_LONG(a->sDAP_Header_DL, b->sDAP_Header_DL);
+  _E1_EQ_CHECK_INT(a->sDAP_Header_UL, b->sDAP_Header_UL);
+  _E1_EQ_CHECK_INT(a->sDAP_Header_DL, b->sDAP_Header_DL);
   return true;
 }
 

openair2/LAYER2/nr_pdcp/cucp_cuup_handler.c

@@ -60,8 +60,11 @@ static void fill_DRB_configList_e1(NR_DRB_ToAddModList_t *DRB_configList, const
     asn1cCalloc(ie->cnAssociation->choice.sdap_Config, sdap_config);
     sdap_config->pdu_Session = pdu->sessionId;
     /* SDAP */
-    sdap_config->sdap_HeaderDL = drb->sdap_config.sDAP_Header_DL;
-    sdap_config->sdap_HeaderUL = drb->sdap_config.sDAP_Header_UL;
+    /* Convert from internal representation to ASN.1 enum:
+     * Internal: false=absent, true=present (or uninitialized=false means absent)
+     * ASN.1: 0=present, 1=absent */
+    sdap_config->sdap_HeaderDL = drb->sdap_config.sDAP_Header_DL ? NR_SDAP_Config__sdap_HeaderDL_present : NR_SDAP_Config__sdap_HeaderDL_absent;
+    sdap_config->sdap_HeaderUL = drb->sdap_config.sDAP_Header_UL ? NR_SDAP_Config__sdap_HeaderUL_present : NR_SDAP_Config__sdap_HeaderUL_absent;
     sdap_config->defaultDRB    = drb->sdap_config.defaultDRB;
     asn1cCalloc(sdap_config->mappedQoS_FlowsToAdd, FlowsToAdd);
     for (int j = 0; j < drb->numQosFlow2Setup; j++) {

openair2/RRC/NR/rrc_gNB_NGAP.c

@@ -299,8 +299,8 @@ static DRB_nGRAN_to_setup_t fill_e1_drb_to_setup(const drb_t *rrc_drb,
   drb_ngran.id = rrc_drb->drb_id;
 
   drb_ngran.sdap_config.defaultDRB = true;
-  drb_ngran.sdap_config.sDAP_Header_UL = session->sdap_config.header_ul_absent ? 1 : 0;
-  drb_ngran.sdap_config.sDAP_Header_DL = session->sdap_config.header_dl_absent ? 1 : 0;
+  drb_ngran.sdap_config.sDAP_Header_UL = session->sdap_config.header_ul_absent ? false : true;
+  drb_ngran.sdap_config.sDAP_Header_DL = session->sdap_config.header_dl_absent ? false : true;
 
   drb_ngran.pdcp_config = set_bearer_context_pdcp_config(rrc_drb->pdcp_config, um_on_default_drb, redcap_cap);
 

tests/nr-cuup/nr-cuup-load-test.c

@@ -418,7 +418,9 @@ static void *sender_thread(void *v)
 {
   struct thr_data *d = v;
 
-  size_t oh = d->is_ul ? 3 : 0;
+  // Overhead: PDCP header (2 bytes) for UL packets
+  // SDAP headers are disabled, so only PDCP header is added
+  size_t oh = d->is_ul ? 2 : 0;
   size_t packet_len = d->data_len + oh;
   uint8_t buf[packet_len];
   memset(buf, 0, packet_len);