Add IP_PORTRANGE* constants to the socket module

`IP_PORTRANGE*` can be used for getting/setting port ranges on a per socket
basis, as opposed to a system wide basis, in conjunction with calls like
`socket.getsockopt` and `socket.setsockopt`.

This functionality is available on \*BSD and Linux.

Signed-off-by: Enji Cooper <yaneurabeya@gmail.com>

Author: ngie-eign

Doc/library/socket.rst

@@ -418,6 +418,7 @@ The AF_* and SOCK_* constants are now :class:`AddressFamily` and
           MSG_*
           SOL_*
           SCM_*
+          IP_PORTRANGE*
           IPPROTO_*
           IPPORT_*
           INADDR_*
@@ -833,6 +834,17 @@ The AF_* and SOCK_* constants are now :class:`AddressFamily` and
 
    .. availability:: not WASI.
 
+.. data:: IP_PORTRANGE
+          IP_PORTRANGE_DEFAULT
+          IP_PORTRANGE_HIGH
+          IP_PORTRANGE_LOW
+
+   These constants are available for manipulating port ranges on a socket-level
+   as opposed to system-level.
+
+   .. availability:: BSD, Linux.
+   .. versionchanged:: 3.15
+
 Functions
 ^^^^^^^^^
 

Modules/socketmodule.c

@@ -8815,6 +8815,14 @@ socket_exec(PyObject *m)
     ADD_INT_MACRO(m, SYSPROTO_CONTROL);
 #endif
 
+    /* Unix-specific macros for setting IP port ranges. */
+#ifdef  IP_PORTRANGE
+    PyModule_AddIntMacro(m, IP_PORTRANGE);
+    PyModule_AddIntMacro(m, IP_PORTRANGE_DEFAULT);
+    PyModule_AddIntMacro(m, IP_PORTRANGE_HIGH);
+    PyModule_AddIntMacro(m, IP_PORTRANGE_LOW);
+#endif
+
     /* Some port configuration */
 #ifdef  IPPORT_RESERVED
     ADD_INT_MACRO(m, IPPORT_RESERVED);