add option to force IMSI attach by not loading NAS ctxt from file

lib/include/srslte/common/interfaces_common.h

@@ -38,17 +38,19 @@ namespace srslte {
 class srslte_nas_config_t
 {
 public:
-  srslte_nas_config_t(uint32_t lcid_ = 0, std::string apn_ = "", std::string user_ = "", std::string pass_ = "")
+  srslte_nas_config_t(uint32_t lcid_ = 0, std::string apn_ = "", std::string user_ = "", std::string pass_ = "", bool force_imsi_attach_ = false)
     :lcid(lcid_),
      apn(apn_),
      user(user_),
-     pass(pass_)
+     pass(pass_),
+     force_imsi_attach(force_imsi_attach_)
     {}
 
   uint32_t    lcid;
   std::string apn;
   std::string user;
   std::string pass;
+  bool        force_imsi_attach;
 };
 
 

srsue/hdr/ue_base.h

@@ -39,6 +39,7 @@
 #include "phy/phy.h"
 #include "upper/usim.h"
 #include "upper/rrc.h"
+#include "upper/nas.h"
 #include "srslte/interfaces/ue_interfaces.h"
 
 #include "srslte/common/logger.h"
@@ -129,9 +130,7 @@ typedef struct {
   usim_args_t   usim;
   rrc_args_t    rrc;
   std::string   ue_category_str;
-  std::string   apn_name;
-  std::string   apn_user;
-  std::string   apn_pass;
+  nas_args_t    nas;
   expert_args_t expert;
 }all_args_t;
 

srsue/hdr/upper/nas.h

@@ -39,6 +39,13 @@ using srslte::byte_buffer_t;
 
 namespace srsue {
 
+typedef struct {
+  std::string apn_name;
+  std::string apn_user;
+  std::string apn_pass;
+  bool        force_imsi_attach;
+} nas_args_t;
+
 // EMM states (3GPP 24.302 v10.0.0)
 typedef enum {
   EMM_STATE_NULL = 0,

srsue/src/main.cc

@@ -84,9 +84,11 @@ void parse_args(all_args_t *args, int argc, char *argv[]) {
                                                                                            "UECapabilityInformation message. Default 0xe6041000")
     ("rrc.ue_category",   bpo::value<string>(&args->ue_category_str)->default_value("4"),  "UE Category (1 to 5)")
 
-    ("nas.apn",   bpo::value<string>(&args->apn_name)->default_value(""),  "Set Access Point Name (APN) for data services")
-    ("nas.user",   bpo::value<string>(&args->apn_user)->default_value(""),  "Username for CHAP authentication")
-    ("nas.pass",   bpo::value<string>(&args->apn_pass)->default_value(""),  "Password for CHAP authentication")
+    ("nas.apn",               bpo::value<string>(&args->nas.apn_name)->default_value(""),  "Set Access Point Name (APN) for data services")
+    ("nas.user",              bpo::value<string>(&args->nas.apn_user)->default_value(""),  "Username for CHAP authentication")
+    ("nas.pass",              bpo::value<string>(&args->nas.apn_pass)->default_value(""),  "Password for CHAP authentication")
+    ("nas.force_imsi_attach", bpo::value<bool>(&args->nas.force_imsi_attach)->default_value(false),  "Whether to always perform an IMSI attach")
+
 
     ("pcap.enable", bpo::value<bool>(&args->pcap.enable)->default_value(false), "Enable MAC packet captures for wireshark")
     ("pcap.filename", bpo::value<string>(&args->pcap.filename)->default_value("ue.pcap"), "MAC layer capture filename")

srsue/src/ue.cc

@@ -210,7 +210,7 @@ bool ue::init(all_args_t *args_) {
   rlc.init(&pdcp, &rrc, this, &rlc_log, &mac, 0 /* RB_ID_SRB0 */);
   pdcp.init(&rlc, &rrc, &gw, &pdcp_log, 0 /* RB_ID_SRB0 */, SECURITY_DIRECTION_UPLINK);
 
-  srslte_nas_config_t nas_cfg(1, args->apn_name, args->apn_user, args->apn_pass); /* RB_ID_SRB1 */
+  srslte_nas_config_t nas_cfg(1, args->nas.apn_name, args->nas.apn_user, args->nas.apn_pass, args->nas.force_imsi_attach); /* RB_ID_SRB1 */
   nas.init(usim, &rrc, &gw, &nas_log, nas_cfg);
   gw.init(&pdcp, &nas, &gw_log, 3 /* RB_ID_DRB1 */);
   gw.set_netmask(args->expert.ip_netmask);

srsue/src/upper/nas.cc

@@ -1364,6 +1364,11 @@ bool nas::read_ctxt_file(nas_sec_ctxt *ctxt)
     return false;
   }
 
+  if (cfg.force_imsi_attach) {
+    nas_log->info("Skip reading context from file.\n");
+    return false;
+  }
+
   file.open(".ctxt", std::ios::in);
   if(file.is_open()) {
     if(!readvar(file, "m_tmsi=",        &ctxt->guti.m_tmsi))        {return false;}

srsue/ue.conf.example

@@ -120,10 +120,15 @@ imei = 353490069873319
 # NAS configuration
 #
 # apn:               Set Access Point Name (APN)
+# user:              Username for CHAP authentication
+# pass:              Password for CHAP authentication
+# force_imsi_attach: Whether to always perform an IMSI
 #####################################################################
 [nas]
-# apn = internetinternet
-
+#apn = internetinternet
+#user = srsuser
+#pass = srspass
+#force_imsi_attach = false
 
 [gui]
 enable = false