add srsUE parameter to change netns before creating TUN in GW

srsue/hdr/stack/upper/gw.h

@@ -41,6 +41,7 @@ struct gw_args_t {
     std::string gw_level;
     int         gw_hex_limit;
   } log;
+  std::string netns;
   std::string tun_dev_name;
   std::string tun_dev_netmask;
 };
@@ -78,6 +79,7 @@ private:
 
   bool         running      = false;
   bool         run_enable   = false;
+  int32_t      netns_fd     = 0;
   int32_t      tun_fd       = 0;
   struct ifreq ifr          = {};
   int32_t      sock         = 0;

srsue/src/main.cc

@@ -152,6 +152,7 @@ static int parse_args(all_args_t* args, int argc, char* argv[])
     ("usim.pin", bpo::value<string>(&args->stack.usim.pin), "PIN in case real SIM card is used")
     ("usim.reader", bpo::value<string>(&args->stack.usim.reader)->default_value(""), "Force specific PCSC reader. Default: Try all available readers.")
 
+    ("gw.netns", bpo::value<string>(&args->gw.netns)->default_value(""), "Network namespace to for TUN device (empty for default netns)")
     ("gw.ip_devname", bpo::value<string>(&args->gw.tun_dev_name)->default_value("tun_srsue"), "Name of the tun_srsue device")
     ("gw.ip_netmask", bpo::value<string>(&args->gw.tun_dev_netmask)->default_value("255.255.255.0"), "Netmask of the tun_srsue device")
 

srsue/src/stack/upper/gw.cc

@@ -342,12 +342,24 @@ int gw::init_if(char* err_str)
     return SRSLTE_ERROR_ALREADY_STARTED;
   }
 
+  // change into netns
+  if (!args.netns.empty()) {
+    std::string netns("/run/netns/");
+    netns += args.netns;
+    netns_fd = open(netns.c_str(), O_RDONLY);
+    if (setns(netns_fd, CLONE_NEWNET) == -1) {
+      err_str = strerror(errno);
+      log.error("Failed to change netns: %s\n", err_str);
+      return SRSLTE_ERROR_CANT_START;
+    }
+  }
+
   // Construct the TUN device
   tun_fd = open("/dev/net/tun", O_RDWR);
   log.info("TUN file descriptor = %d\n", tun_fd);
   if (0 > tun_fd) {
     err_str = strerror(errno);
-    log.debug("Failed to open TUN device: %s\n", err_str);
+    log.error("Failed to open TUN device: %s\n", err_str);
     return SRSLTE_ERROR_CANT_START;
   }
 
@@ -358,7 +370,7 @@ int gw::init_if(char* err_str)
   ifr.ifr_ifrn.ifrn_name[IFNAMSIZ - 1] = 0;
   if (0 > ioctl(tun_fd, TUNSETIFF, &ifr)) {
     err_str = strerror(errno);
-    log.debug("Failed to set TUN device name: %s\n", err_str);
+    log.error("Failed to set TUN device name: %s\n", err_str);
     close(tun_fd);
     return SRSLTE_ERROR_CANT_START;
   }
@@ -367,14 +379,14 @@ int gw::init_if(char* err_str)
   sock = socket(AF_INET, SOCK_DGRAM, 0);
   if (0 > ioctl(sock, SIOCGIFFLAGS, &ifr)) {
     err_str = strerror(errno);
-    log.debug("Failed to bring up socket: %s\n", err_str);
+    log.error("Failed to bring up socket: %s\n", err_str);
     close(tun_fd);
     return SRSLTE_ERROR_CANT_START;
   }
   ifr.ifr_flags |= IFF_UP | IFF_RUNNING;
   if (0 > ioctl(sock, SIOCSIFFLAGS, &ifr)) {
     err_str = strerror(errno);
-    log.debug("Failed to set socket flags: %s\n", err_str);
+    log.error("Failed to set socket flags: %s\n", err_str);
     close(tun_fd);
     return SRSLTE_ERROR_CANT_START;
   }

srsue/ue.conf.example

@@ -167,10 +167,12 @@ imei = 353490069873319
 #####################################################################
 # GW configuration
 #
+# netns:                Network namespace to create TUN device. Default: empty
 # ip_devname:           Name of the tun_srsue device. Default: tun_srsue
 # ip_netmask:           Netmask of the tun_srsue device. Default: 255.255.255.0
 #####################################################################
 [gw]
+#netns =
 #ip_devname = tun_srsue
 #ip_netmask = 255.255.255.0