1 files changed, 52 insertions, 6 deletions

diff --git a/server/InterfaceController.cpp b/server/InterfaceController.cpp
index eac4fbf2..1d0a8e0d 100644
--- a/server/InterfaceController.cpp
+++ b/server/InterfaceController.cpp
@@ -17,6 +17,7 @@
 #include <dirent.h>
 #include <errno.h>
 #include <malloc.h>
+#include <sys/socket.h>
 
 #define LOG_TAG "InterfaceController"
 #include <android-base/file.h>
@@ -29,6 +30,7 @@
 #include "RouteController.h"
 
 using android::base::StringPrintf;
+using android::base::ReadFileToString;
 using android::base::WriteStringToFile;
 
 namespace {
@@ -39,15 +41,25 @@ const char ipv4_neigh_conf_dir[] = "/proc/sys/net/ipv4/neigh";
 
 const char ipv6_neigh_conf_dir[] = "/proc/sys/net/ipv6/neigh";
 
+const char proc_net_path[] = "/proc/sys/net";
 const char sys_net_path[] = "/sys/class/net";
 
 const char wl_util_path[] = "/vendor/xbin/wlutil";
 
-bool isInterfaceName(const char *name) {
-    return strcmp(name, ".") &&
-            strcmp(name, "..") &&
-            strcmp(name, "default") &&
-            strcmp(name, "all");
+inline bool isNormalPathComponent(const char *component) {
+    return (strcmp(component, ".") != 0) &&
+           (strcmp(component, "..") != 0) &&
+           (strchr(component, '/') == nullptr);
+}
+
+inline bool isAddressFamilyPathComponent(const char *component) {
+    return strcmp(component, "ipv4") == 0 || strcmp(component, "ipv6") == 0;
+}
+
+inline bool isInterfaceName(const char *name) {
+    return isNormalPathComponent(name) &&
+           (strcmp(name, "default") != 0) &&
+           (strcmp(name, "all") != 0);
 }
 
 int writeValueToPath(
@@ -81,6 +93,21 @@ void setIPv6UseOutgoingInterfaceAddrsOnly(const char *value) {
     setOnAllInterfaces(ipv6_proc_path, "use_oif_addrs_only", value);
 }
 
+std::string getParameterPathname(
+        const char *family, const char *which, const char *interface, const char *parameter) {
+    if (!isAddressFamilyPathComponent(family)) {
+        errno = EAFNOSUPPORT;
+        return "";
+    } else if (!isNormalPathComponent(which) ||
+               !isInterfaceName(interface) ||
+               !isNormalPathComponent(parameter)) {
+        errno = EINVAL;
+        return "";
+    }
+
+    return StringPrintf("%s/%s/%s/%s/%s", proc_net_path, family, which, interface, parameter);
+}
+
 }  // namespace
 
 void InterfaceController::initializeAll() {
@@ -201,7 +228,6 @@ int InterfaceController::setMtu(const char *interface, const char *mtu)
     return writeValueToPath(sys_net_path, interface, "mtu", mtu);
 }
 
-
 int InterfaceController::addAddress(const char *interface,
         const char *addrString, int prefixLength) {
     return ifc_add_address(interface, addrString, prefixLength);
@@ -212,6 +238,26 @@ int InterfaceController::delAddress(const char *interface,
     return ifc_del_address(interface, addrString, prefixLength);
 }
 
+int InterfaceController::getParameter(
+        const char *family, const char *which, const char *interface, const char *parameter,
+        std::string *value) {
+    const std::string path(getParameterPathname(family, which, interface, parameter));
+    if (path.empty()) {
+        return -errno;
+    }
+    return ReadFileToString(path, value) ? 0 : -errno;
+}
+
+int InterfaceController::setParameter(
+        const char *family, const char *which, const char *interface, const char *parameter,
+        const char *value) {
+    const std::string path(getParameterPathname(family, which, interface, parameter));
+    if (path.empty()) {
+        return -errno;
+    }
+    return WriteStringToFile(value, path) ? 0 : -errno;
+}
+
 void InterfaceController::setBaseReachableTimeMs(unsigned int millis) {
     std::string value(StringPrintf("%u", millis));
     setOnAllInterfaces(ipv4_neigh_conf_dir, "base_reachable_time_ms", value.c_str());