Add a function to get Wifi SSID to net_util.

net/base/net_util_linux.cc

Index: net/base/net_util_linux.cc
diff --git a/net/base/net_util_linux.cc b/net/base/net_util_linux.cc
index 36c9eb706ecfdaaa4d5cff4abdc73aac357795fd..782929a00e7b4a6be8bdc7dad9561208aa16bc79 100644
--- a/net/base/net_util_linux.cc
+++ b/net/base/net_util_linux.cc
@@ -103,6 +103,22 @@ NetworkChangeNotifier::ConnectionType GetInterfaceConnectionType(
   return NetworkChangeNotifier::CONNECTION_UNKNOWN;
 }
 
+std::string GetInterfaceSSID(const std::string& ifname) {
+  int ioctl_socket = socket(AF_INET, SOCK_DGRAM, 0);
+  if (ioctl_socket < 0)
+    return "";
+  struct iwreq wreq;
+  memset(&wreq, 0, sizeof(wreq));
+  strncpy(wreq.ifr_name, ifname.c_str(), IFNAMSIZ - 1);
+
+  char ssid[IW_ESSID_MAX_SIZE + 1] = {0};
+  wreq.u.essid.pointer = ssid;
+  wreq.u.essid.length = IW_ESSID_MAX_SIZE;
+  int rv = ioctl(ioctl_socket, SIOCGIWESSID, &wreq);
+  close(ioctl_socket);
+  return (rv == 0) ? ssid : "";
+}
+
 bool GetNetworkListImpl(
     NetworkInterfaceList* networks,
     int policy,
@@ -172,6 +188,26 @@ bool GetNetworkListImpl(
   return true;
 }
 
+std::string GetWifiSSIDFromInterfaceListInternal(
+    const NetworkInterfaceList& interfaces,
+    internal::GetInterfaceSSIDFunction get_interface_ssid) {
+  std::string connected_ssid;
+  bool first = true;
+  for (size_t i = 0; i < interfaces.size(); ++i) {
+    LOG(ERROR) << "Interface " << i << ": " << interfaces[i].name;

[meacer, 2015/02/04 01:34:33]

Debug cruft, to be removed.

+    if (interfaces[i].type != NetworkChangeNotifier::CONNECTION_WIFI)
+      return "";
+    std::string ssid = get_interface_ssid(interfaces[i].name);
+    if (first) {
+      first = false;
+      connected_ssid = ssid;
+    } else if (ssid != connected_ssid) {
+      return "";
+    }
+  }
+  return connected_ssid;
+}
+
 }  // namespace internal
 
 bool GetNetworkList(NetworkInterfaceList* networks, int policy) {
@@ -186,4 +222,10 @@ bool GetNetworkList(NetworkInterfaceList* networks, int policy) {
       &internal::AddressTrackerLinux::GetInterfaceName);
 }
 
+std::string GetWifiSSIDFromInterfaceList(
+    const NetworkInterfaceList& interfaces) {
+  return internal::GetWifiSSIDFromInterfaceListInternal(
+      interfaces, internal::GetInterfaceSSID);
+}
+
 }  // namespace net