Add some network utility functions for examining a socket's remote IP

renderdoc/os/os_specific.h

@@ -154,6 +154,8 @@ public:
 
   Socket *AcceptClient(bool wait);
 
+  uint32_t GetRemoteIP() const;
+
   bool IsRecvDataWaiting();
 
   bool SendDataBlocking(const void *buf, uint32_t length);
@@ -166,6 +168,31 @@ private:
 Socket *CreateServerSocket(const char *addr, uint16_t port, int queuesize);
 Socket *CreateClientSocket(const char *host, uint16_t port, int timeoutMS);
 
+// ip is packed in HOST byte order
+inline uint32_t GetIPOctet(uint32_t ip, uint32_t octet)
+{
+  uint32_t shift = (3 - octet) * 8;
+  uint32_t mask = 0xff << shift;
+
+  return (ip & mask) >> shift;
+}
+
+// returns ip packed in HOST byte order (ie. little endian)
+inline uint32_t MakeIP(uint32_t a, uint32_t b, uint32_t c, uint32_t d)
+{
+  return ((a & 0xff) << 24) | ((b & 0xff) << 16) | ((c & 0xff) << 8) | ((d & 0xff) << 0);
+}
+
+// checks if `ip` matches the given `range` and subnet `mask`
+inline bool MatchIPMask(uint32_t ip, uint32_t range, uint32_t mask)
+{
+  return (ip & mask) == (range & mask);
+}
+
+// parses the null-terminated string at 'str' for CIDR notation IP range
+// aaa.bbb.ccc.ddd/nn
+bool ParseIPRangeCIDR(const char *str, uint32_t &ip, uint32_t &mask);
+
 void Init();
 void Shutdown();
 };

renderdoc/os/posix/posix_network.cpp

@@ -69,6 +69,16 @@ bool Socket::Connected() const
   return (int)socket != -1;
 }
 
+uint32_t Socket::GetRemoteIP() const
+{
+  sockaddr_in addr = {};
+  socklen_t len = sizeof(addr);
+
+  getpeername((int)socket, (sockaddr *)&addr, &len);
+
+  return ntohl(addr.sin_addr.s_addr);
+}
+
 Socket *Socket::AcceptClient(bool wait)
 {
   do
@@ -335,4 +345,25 @@ Socket *CreateClientSocket(const char *host, uint16_t port, int timeoutMS)
   RDCWARN("Failed to connect to %S:%d", host, port);
   return NULL;
 }
+
+bool ParseIPRangeCIDR(const char *str, uint32_t &ip, uint32_t &mask)
+{
+  uint32_t a = 0, b = 0, c = 0, d = 0, num = 0;
+
+  int ret = sscanf(str, "%u.%u.%u.%u/%u", &a, &b, &c, &d, &num);
+
+  ip = MakeIP(a, b, c, d);
+
+  if(num == 0)
+  {
+    mask = 0;
+  }
+  else
+  {
+    num = 32 - num;
+    mask = ((~0U) >> num) << num;
+  }
+
+  return ret == 5;
+}
 };

renderdoc/os/win32/win32_network.cpp

@@ -64,6 +64,16 @@ bool Socket::Connected() const
   return (SOCKET)socket != INVALID_SOCKET;
 }
 
+uint32_t Socket::GetRemoteIP() const
+{
+  sockaddr_in addr = {};
+  socklen_t len = sizeof(addr);
+
+  getpeername((SOCKET)socket, (sockaddr *)&addr, &len);
+
+  return ntohl(addr.sin_addr.s_addr);
+}
+
 Socket *Socket::AcceptClient(bool wait)
 {
   do
@@ -350,4 +360,25 @@ Socket *CreateClientSocket(const char *host, uint16_t port, int timeoutMS)
   RDCWARN("Failed to connect to %s:%d", host, port);
   return NULL;
 }
+
+bool ParseIPRangeCIDR(const char *str, uint32_t &ip, uint32_t &mask)
+{
+  uint32_t a = 0, b = 0, c = 0, d = 0, num = 0;
+
+  int ret = sscanf_s(str, "%u.%u.%u.%u/%u", &a, &b, &c, &d, &num);
+
+  ip = MakeIP(a, b, c, d);
+
+  if(num == 0)
+  {
+    mask = 0;
+  }
+  else
+  {
+    num = 32 - num;
+    mask = ((~0U) >> num) << num;
+  }
+
+  return ret == 5;
+}
 };