share C function to retrieve MTU across all UNIXes

1 files changed, 38 insertions, 8 deletions

diff --git a/psutil/_psutil_posix.c b/psutil/_psutil_posix.c
index 8098fbb9..54506322 100644
--- a/psutil/_psutil_posix.c
+++ b/psutil/_psutil_posix.c
@@ -245,6 +245,41 @@ error:
 
 
 /*
+ * Return NIC MTU. References:
+ * http://www.i-scream.org/libstatgrab/
+ */
+static PyObject *
+psutil_net_if_mtu(PyObject *self, PyObject *args) {
+    char *nic_name;
+    int sock = 0;
+    int ret;
+    int mtu;
+    struct ifreq ifr;
+
+    if (! PyArg_ParseTuple(args, "s", &nic_name))
+        return NULL;
+
+    sock = socket(AF_INET, SOCK_DGRAM, 0);
+    if (sock == -1)
+        goto error;
+
+    strncpy(ifr.ifr_name, nic_name, sizeof(ifr.ifr_name));
+    ret = ioctl(sock, SIOCGIFMTU, &ifr);
+    if (ret == -1)
+        goto error;
+    mtu = ifr.ifr_mtu;
+
+    return Py_BuildValue("i", mtu);
+
+error:
+    if (sock != 0)
+        close(sock);
+    PyErr_SetFromErrno(PyExc_OSError);
+    return NULL;
+}
+
+
+/*
  * net_if_stats() implementation. This is here because it is common
  * to both OSX and FreeBSD and I didn't know where else to put it.
  */
@@ -402,7 +437,6 @@ psutil_net_if_stats(PyObject *self, PyObject *args) {
     int ret;
     int duplex;
     int speed;
-    int mtu;
     struct ifreq ifr;
     struct ifmediareq ifmed;
 
@@ -426,12 +460,6 @@ psutil_net_if_stats(PyObject *self, PyObject *args) {
         py_is_up = Py_False;
     Py_INCREF(py_is_up);
 
-    // MTU
-    ret = ioctl(sock, SIOCGIFMTU, &ifr);
-    if (ret == -1)
-        goto error;
-    mtu = ifr.ifr_mtu;
-
     // speed / duplex
     memset(&ifmed, 0, sizeof(struct ifmediareq));
     strlcpy(ifmed.ifm_name, nic_name, sizeof(ifmed.ifm_name));
@@ -453,7 +481,7 @@ psutil_net_if_stats(PyObject *self, PyObject *args) {
     close(sock);
     Py_DECREF(py_is_up);
 
-    return Py_BuildValue("[Oiii]", py_is_up, duplex, speed, mtu);
+    return Py_BuildValue("[Oii]", py_is_up, duplex, speed);
 
 error:
     Py_XDECREF(py_is_up);
@@ -476,6 +504,8 @@ PsutilMethods[] = {
      "Set process priority"},
     {"net_if_addrs", psutil_net_if_addrs, METH_VARARGS,
      "Retrieve NICs information"},
+    {"net_if_mtu", psutil_net_if_mtu, METH_VARARGS,
+     "Retrieve NIC MTU"},
 #if defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__APPLE__) || defined(__NetBSD__)
     {"net_if_stats", psutil_net_if_stats, METH_VARARGS,
      "Return NIC stats."},