Add WiFi SSID getter to NetworkChangeNotifier.

net/base/address_tracker_linux.cc

Index: net/base/address_tracker_linux.cc
diff --git a/net/base/address_tracker_linux.cc b/net/base/address_tracker_linux.cc
index 731bf4f97785ebf45837c35a4fe4033bd4ffffff..d94104da6294075287bc378d62b954873fb1ab74 100644
--- a/net/base/address_tracker_linux.cc
+++ b/net/base/address_tracker_linux.cc
@@ -6,6 +6,7 @@
 
 #include <errno.h>
 #include <linux/if.h>
+#include <linux/wireless.h>
 #include <sys/ioctl.h>
 
 #include "base/files/scoped_file.h"
@@ -78,6 +79,22 @@ bool GetAddress(const struct nlmsghdr* header,
   return true;
 }
 
+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 : "";
+}
+
 }  // namespace
 
 // static
@@ -95,6 +112,26 @@ char* AddressTrackerLinux::GetInterfaceName(int interface_index, char* buf) {
   return buf;
 }
 
+// static
+std::string AddressTrackerLinux::ConnectionSSIDFromInterfaceList(
+    const NetworkInterfaceList& interfaces,
+    GetInterfaceSSIDFunction get_interface_ssid) {
+  std::string connected_ssid;
+  bool first = true;
+  for (size_t i = 0; i < interfaces.size(); ++i) {
+    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;
+}
+
 AddressTrackerLinux::AddressTrackerLinux()
     : get_interface_name_(GetInterfaceName),
       address_callback_(base::Bind(&base::DoNothing)),
@@ -223,6 +260,7 @@ void AddressTrackerLinux::AbortAndForceOnline() {
   current_connection_type_ = NetworkChangeNotifier::CONNECTION_UNKNOWN;
   connection_type_initialized_ = true;
   connection_type_initialized_cv_.Signal();
+  current_wifi_ssid_ = "";
 }
 
 AddressTrackerLinux::AddressMap AddressTrackerLinux::GetAddressMap() const {
@@ -247,6 +285,12 @@ AddressTrackerLinux::GetCurrentConnectionType() {
   return current_connection_type_;
 }
 
+std::string AddressTrackerLinux::GetCurrentWiFiSSID() {
+  // Don't wait for initialization, return an empty SSID if not initialized.
+  AddressTrackerAutoLock lock(*this, wifi_ssid_lock_);
+  return current_wifi_ssid_;
+}
+
 void AddressTrackerLinux::ReadMessages(bool* address_changed,
                                        bool* link_changed,
                                        bool* tunnel_changed) {
@@ -275,7 +319,7 @@ void AddressTrackerLinux::ReadMessages(bool* address_changed,
     HandleMessage(buffer, rv, address_changed, link_changed, tunnel_changed);
   }
   if (*link_changed || *address_changed)
-    UpdateCurrentConnectionType();
+    UpdateCurrentConnectionTypeAndSSID();
 }
 
 void AddressTrackerLinux::HandleMessage(char* buffer,
@@ -395,7 +439,7 @@ bool AddressTrackerLinux::IsTunnelInterface(int interface_index) const {
   return strncmp(get_interface_name_(interface_index, buf), "tun", 3) == 0;
 }
 
-void AddressTrackerLinux::UpdateCurrentConnectionType() {
+void AddressTrackerLinux::UpdateCurrentConnectionTypeAndSSID() {
   AddressTrackerLinux::AddressMap address_map = GetAddressMap();
   base::hash_set<int> online_links = GetOnlineLinks();
 
@@ -414,16 +458,24 @@ void AddressTrackerLinux::UpdateCurrentConnectionType() {
   NetworkInterfaceList networks;
   NetworkChangeNotifier::ConnectionType type =
       NetworkChangeNotifier::CONNECTION_NONE;
+  std::string ssid;
   if (GetNetworkListImpl(&networks, 0, online_links, address_map,
                          get_interface_name_)) {
     type = NetworkChangeNotifier::ConnectionTypeFromInterfaceList(networks);
+    ssid = ConnectionSSIDFromInterfaceList(networks, GetInterfaceSSID);
   } else {
     type = online_links.empty() ? NetworkChangeNotifier::CONNECTION_NONE
                                 : NetworkChangeNotifier::CONNECTION_UNKNOWN;
   }
 
-  AddressTrackerAutoLock lock(*this, connection_type_lock_);
-  current_connection_type_ = type;
+  {
+    AddressTrackerAutoLock lock(*this, connection_type_lock_);
+    current_connection_type_ = type;
+  }
+  {
+    AddressTrackerAutoLock lock(*this, wifi_ssid_lock_);
+    current_wifi_ssid_ = ssid;
+  }
 }
 
 AddressTrackerLinux::AddressTrackerAutoLock::AddressTrackerAutoLock(