bpo-27584: New addition of vSockets to the python socket module (#2489)

* bpo-27584: New addition of vSockets to the python socket module

Support for AF_VSOCK on Linux only

* bpo-27584: Fixes for V2

Fixed syntax and naming problems.
Fixed #ifdef AF_VSOCK checking
Restored original aclocal.m4

* bpo-27584: Fixes for V3

Added checking for fcntl and thread modules.

* bpo-27584: Fixes for V4

Fixed white space error

* bpo-27584: Fixes for V5

Added back comma in (CID, port).

* bpo-27584: Fixes for V6

Added news file.
socket.rst now reflects first Linux introduction of AF_VSOCK.
Fixed get_cid in test_socket.py.
Replaced PyLong_FromLong with PyLong_FromUnsignedLong in socketmodule.c
Got rid of extra AF_VSOCK #define.
Added sockaddr_vm to sock_addr.

* bpo-27584: Fixes for V7

Minor cleanup.

* bpo-27584: Fixes for V8

Put back #undef AF_VSOCK as it is  necessary when vm_sockets.h is not installed.

2 files changed, 100 insertions, 2 deletions

diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c
index 37626e6..a431e25 100644
--- a/Modules/socketmodule.c
+++ b/Modules/socketmodule.c
@@ -1225,6 +1225,14 @@ makesockaddr(SOCKET_T sockfd, struct sockaddr *addr, size_t addrlen, int proto)
        }
 #endif /* AF_NETLINK */
 
+#if defined(AF_VSOCK)
+       case AF_VSOCK:
+       {
+           struct sockaddr_vm *a = (struct sockaddr_vm *) addr;
+           return Py_BuildValue("II", a->svm_cid, a->svm_port);
+       }
+#endif /* AF_VSOCK */
+
 #ifdef ENABLE_IPV6
     case AF_INET6:
     {
@@ -1586,6 +1594,32 @@ getsockaddrarg(PySocketSockObject *s, PyObject *args,
     }
 #endif
 
+#if defined(AF_VSOCK)
+    case AF_VSOCK:
+    {
+        struct sockaddr_vm* addr;
+        int port, cid;
+        addr = (struct sockaddr_vm *)addr_ret;
+        memset(addr, 0, sizeof(struct sockaddr_vm));
+        if (!PyTuple_Check(args)) {
+            PyErr_Format(
+                PyExc_TypeError,
+                "getsockaddrarg: "
+                "AF_VSOCK address must be tuple, not %.500s",
+                Py_TYPE(args)->tp_name);
+            return 0;
+        }
+        if (!PyArg_ParseTuple(args, "II:getsockaddrarg", &cid, &port))
+            return 0;
+        addr->svm_family = s->sock_family;
+        addr->svm_port = port;
+        addr->svm_cid = cid;
+        *len_ret = sizeof(*addr);
+        return 1;
+    }
+#endif
+
+
 #ifdef AF_RDS
     case AF_RDS:
         /* RDS sockets use sockaddr_in: fall-through */
@@ -2103,6 +2137,14 @@ getsockaddrlen(PySocketSockObject *s, socklen_t *len_ret)
     }
 #endif
 
+#if defined(AF_VSOCK)
+       case AF_VSOCK:
+       {
+           *len_ret = sizeof (struct sockaddr_vm);
+           return 1;
+       }
+#endif
+
 #ifdef AF_RDS
     case AF_RDS:
         /* RDS sockets use sockaddr_in: fall-through */
@@ -2598,6 +2640,21 @@ sock_setsockopt(PySocketSockObject *s, PyObject *args)
     unsigned int optlen;
     PyObject *none;
 
+#ifdef AF_VSOCK
+    if (s->sock_family == AF_VSOCK) {
+        uint64_t vflag; // Must be set width of 64 bits
+        /* setsockopt(level, opt, flag) */
+        if (PyArg_ParseTuple(args, "iiK:setsockopt",
+                         &level, &optname, &vflag)) {
+            // level should always be set to AF_VSOCK
+            res = setsockopt(s->sock_fd, level, optname,
+                         (void*)&vflag, sizeof vflag);
+            goto done;
+        }
+        return NULL;
+    }
+#endif
+
     /* setsockopt(level, opt, flag) */
     if (PyArg_ParseTuple(args, "iii:setsockopt",
                          &level, &optname, &flag)) {
@@ -2668,20 +2725,39 @@ sock_getsockopt(PySocketSockObject *s, PyObject *args)
     int res;
     PyObject *buf;
     socklen_t buflen = 0;
+    int flag = 0;
+    socklen_t flagsize;
 
     if (!PyArg_ParseTuple(args, "ii|i:getsockopt",
                           &level, &optname, &buflen))
         return NULL;
 
     if (buflen == 0) {
-        int flag = 0;
-        socklen_t flagsize = sizeof flag;
+#ifdef AF_VSOCK
+        if (s->sock_family == AF_VSOCK) {
+            uint64_t vflag = 0; // Must be set width of 64 bits
+            flagsize = sizeof vflag;
+            res = getsockopt(s->sock_fd, level, optname,
+                         (void *)&vflag, &flagsize);
+            if (res < 0)
+                return s->errorhandler();
+            return PyLong_FromUnsignedLong(vflag);
+        }
+#endif
+        flagsize = sizeof flag;
         res = getsockopt(s->sock_fd, level, optname,
                          (void *)&flag, &flagsize);
         if (res < 0)
             return s->errorhandler();
         return PyLong_FromLong(flag);
     }
+#ifdef AF_VSOCK
+    if (s->sock_family == AF_VSOCK) {
+        PyErr_SetString(PyExc_OSError,
+                        "getsockopt string buffer not allowed");
+        return NULL;
+        }
+#endif
     if (buflen <= 0 || buflen > 1024) {
         PyErr_SetString(PyExc_OSError,
                         "getsockopt buflen out of range");
@@ -6645,6 +6721,19 @@ PyInit__socket(void)
     PyModule_AddIntMacro(m, NETLINK_CRYPTO);
 #endif
 #endif /* AF_NETLINK */
+
+#ifdef AF_VSOCK
+    PyModule_AddIntConstant(m, "AF_VSOCK", AF_VSOCK);
+    PyModule_AddIntConstant(m, "SO_VM_SOCKETS_BUFFER_SIZE", 0);
+    PyModule_AddIntConstant(m, "SO_VM_SOCKETS_BUFFER_MIN_SIZE", 1);
+    PyModule_AddIntConstant(m, "SO_VM_SOCKETS_BUFFER_MAX_SIZE", 2);
+    PyModule_AddIntConstant(m, "VMADDR_CID_ANY", 0xffffffff);
+    PyModule_AddIntConstant(m, "VMADDR_PORT_ANY", 0xffffffff);
+    PyModule_AddIntConstant(m, "VMADDR_CID_HOST", 2);
+    PyModule_AddIntConstant(m, "VM_SOCKETS_INVALID_VERSION", 0xffffffff);
+    PyModule_AddIntConstant(m, "IOCTL_VM_SOCKETS_GET_LOCAL_CID",  _IO(7, 0xb9));
+#endif
+
 #ifdef AF_ROUTE
     /* Alias to emulate 4.4BSD */
     PyModule_AddIntMacro(m, AF_ROUTE);
diff --git a/Modules/socketmodule.h b/Modules/socketmodule.h
index 03f982b..03dbf18 100644
--- a/Modules/socketmodule.h
+++ b/Modules/socketmodule.h
@@ -107,6 +107,12 @@ typedef int socklen_t;
 #define SOL_ALG 279
 #endif
 
+#ifdef HAVE_LINUX_VM_SOCKETS_H
+# include <linux/vm_sockets.h>
+#else
+# undef AF_VSOCK
+#endif
+
 /* Linux 3.19 */
 #ifndef ALG_SET_AEAD_ASSOCLEN
 #define ALG_SET_AEAD_ASSOCLEN           4
@@ -193,6 +199,9 @@ typedef union sock_addr {
 #ifdef HAVE_SOCKADDR_ALG
     struct sockaddr_alg alg;
 #endif
+#ifdef AF_VSOCK 
+    struct sockaddr_vm vm;
+#endif
 } sock_addr_t;
 
 /* The object holding a socket.  It holds some extra information,