SPGW: add Non nat config option

Summary: This option would turn off NAT rule installation on PGW init.

Reviewed By: ardzoht

Differential Revision: D22080407

fbshipit-source-id: f8a4eb3cd2db1623ac58ebb603db03071ba7a008

Author: pshelar

lte/gateway/c/oai/include/pgw_config.h

@@ -83,6 +83,8 @@
 #define PGW_CONFIG_P_CSCF_IPV4_ADDRESS "P_CSCF_IPV4_ADDRESS"
 #define PGW_CONFIG_P_CSCF_IPV6_ADDRESS "P_CSCF_IPV6_ADDRESS"
 
+#define PGW_CONFIG_STRING_NAT_ENABLED "ENABLE_NAT"
+
 // may be more
 #define PGW_MAX_ALLOCATED_PDN_ADDRESSES 1024
 #define PGW_NUM_UE_POOL_MAX 16
@@ -119,6 +121,7 @@ typedef struct pgw_config_s {
   bool force_push_pco;
   uint16_t ue_mtu;
   bool relay_enabled;
+  bool enable_nat;
 
   struct {
     bool enabled;

lte/gateway/c/oai/lib/openflow/controller/PagingApplication.cpp

@@ -104,9 +104,10 @@ void PagingApplication::install_default_flow(
   fluid_base::OFConnection *ofconn,
   const OpenflowMessenger &messenger)
 {
-  // Get assigned IP block from mobilityd
-  struct in_addr netaddr;
-  uint32_t prefix;
+  // Get assigned IP block from mobilityd,
+  // In case of error allow entire IP space.
+  struct in_addr netaddr = { .s_addr = INADDR_ANY };
+  uint32_t prefix = 0;
   int ret = get_assigned_ipv4_block(0, &netaddr, &prefix);
 
   // Convert to string for logging

lte/gateway/c/oai/tasks/gtpv1-u/gtpv1u_task.c

@@ -75,11 +75,17 @@ int gtpv1u_init(
     return -1;
   }
 
-  rv = get_ip_block(&netaddr, &netmask);
-  if (rv != 0) {
-    OAILOG_CRITICAL(
-      LOG_GTPV1U, "ERROR in getting assigned IP block from mobilityd\n");
-    return -1;
+  if (spgw_config->pgw_config.enable_nat) {
+    rv = get_ip_block(&netaddr, &netmask);
+    if (rv != 0) {
+        OAILOG_CRITICAL(
+          LOG_GTPV1U, "ERROR in getting assigned IP block from mobilityd\n");
+        return -1;
+    }
+  } else {
+    // Allow All IPs in Non-NAT case.
+    netaddr.s_addr = INADDR_ANY;
+    netmask = 0;
   }
 
   // Init GTP device, using the same MTU as SGi.

lte/gateway/c/oai/tasks/sgw/pgw_config.c

@@ -155,7 +155,7 @@ int pgw_config_process(pgw_config_t* config_pP) {
     close(fd);
   }
   // Get IP block information
-  {
+  if (config_pP->enable_nat) {
     int rv = 0;
     struct in_addr netaddr;
     uint32_t netmask;
@@ -199,6 +199,8 @@ int pgw_config_process(pgw_config_t* config_pP) {
           inet_ntoa(netaddr), netmask, min_mtu - 40);
     }
 #endif
+  } else {
+    OAILOG_DEBUG(LOG_SPGW_APP, "Nat is OFF");
   }
 
   // TODO: Fix me: Add tc support
@@ -231,6 +233,7 @@ int pgw_config_parse_file(pgw_config_t* config_pP) {
   int prefix_mask    = 0;
   char* pcscf_ipv4   = NULL;
   char* pcscf_ipv6   = NULL;
+  char* nat_enabled  = NULL;
 
   config_init(&cfg);
 
@@ -387,6 +390,18 @@ int pgw_config_parse_file(pgw_config_t* config_pP) {
         OAILOG_WARNING(LOG_SPGW_APP, "NO DNS CONFIGURATION FOUND\n");
       }
     }
+    config_pP->enable_nat = true;
+    if (config_setting_lookup_string(setting_pgw, PGW_CONFIG_STRING_NAT_ENABLED,
+                (const char**)&nat_enabled)) {
+      if (strcasecmp(nat_enabled, "false") == 0) {
+        config_pP->enable_nat = false;
+      } else {
+        config_pP->enable_nat = true;
+      }
+      OAILOG_INFO(
+          LOG_SPGW_APP, "Parsing configuration file Nat enable: %s\n",
+          nat_enabled);
+    }
 
     if (config_setting_lookup_string(
             setting_pgw, PGW_CONFIG_P_CSCF_IPV4_ADDRESS,
@@ -577,6 +592,9 @@ void pgw_config_display(pgw_config_t* config_p) {
       inet_ntoa(*((struct in_addr*) &config_p->ipv4.SGI)));
   OAILOG_INFO(
       LOG_SPGW_APP, "    SGi MTU (read)........: %u\n", config_p->ipv4.mtu_SGI);
+  OAILOG_INFO(
+      LOG_SPGW_APP, "    NAT ..................: %s\n",
+      config_p->enable_nat == 0 ? "false" : "true");
   OAILOG_INFO(
       LOG_SPGW_APP, "    User TCP MSS clamping : %s\n",
       config_p->ue_tcp_mss_clamp == 0 ? "false" : "true");

lte/gateway/c/oai/tasks/sgw/sgw_config.c

@@ -369,7 +369,6 @@ int sgw_config_parse_file(sgw_config_t *config_pP)
     }
 #endif
   }
-
   config_destroy(&cfg);
   return RETURNok;
 }

lte/gateway/configs/templates/spgw.conf.template

@@ -75,4 +75,5 @@ P-GW =
     FORCE_PUSH_PROTOCOL_CONFIGURATION_OPTIONS = "no";                           # STRING, {"yes", "no"}.
     UE_MTU                                    = 1400         # MTU - (extended GTPv1 hdr(16 Bytes) + UDP hdr(8) -IPv4(20) hdr + additonal bytes(56)) INTEGER
     RELAY_ENABLED                             = "{{ relay_enabled }}";
+    ENABLE_NAT                                = "{{ enable_nat }}"
 };