1 files changed, 96 insertions, 0 deletions
diff --git a/share/examples/libifconfig/setmtu.c b/share/examples/libifconfig/setmtu.c
new file mode 100644
index 000000000000..06417cb7fc5b
--- /dev/null
+++ b/share/examples/libifconfig/setmtu.c
@@ -0,0 +1,96 @@
+/*
+ * Copyright (c) 2016-2017, Marie Helene Kvello-Aune
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * thislist of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation and/or
+ * other materials provided with the distribution.
+ *
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <err.h>
+#include <errno.h>
+#include <net/if.h>
+#include <sys/ioctl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <libifconfig.h>
+
+
+int
+main(int argc, char *argv[])
+{
+	char *ifname, *ptr;
+	int mtu;
+	ifconfig_handle_t *lifh;
+
+	if (argc != 3) {
+		errx(EINVAL, "Invalid number of arguments."
+		    " First argument should be interface name, second argument"
+		    " should be the MTU to set.");
+	}
+
+	/* We have a static number of arguments. Therefore we can do it simple. */
+	ifname = strdup(argv[1]);
+	mtu = (int)strtol(argv[2], &ptr, 10);
+
+	printf("Interface name: %s\n", ifname);
+	printf("New MTU: %d", mtu);
+
+	lifh = ifconfig_open();
+	if (lifh == NULL) {
+		errx(ENOMEM, "Failed to open libifconfig handle.");
+		return (-1);
+	}
+
+	if (ifconfig_set_mtu(lifh, ifname, mtu) == 0) {
+		printf("Successfully changed MTU of %s to %d\n", ifname, mtu);
+		ifconfig_close(lifh);
+		lifh = NULL;
+		free(ifname);
+		return (0);
+	}
+
+	switch (ifconfig_err_errtype(lifh)) {
+	case SOCKET:
+		warnx("couldn't create socket. This shouldn't happen.\n");
+		break;
+	case IOCTL:
+		if (ifconfig_err_ioctlreq(lifh) == SIOCSIFMTU) {
+			warnx("Failed to set MTU (SIOCSIFMTU)\n");
+		} else {
+			warnx(
+				"Failed to set MTU due to error in unexpected ioctl() call %lu. Error code: %i.\n",
+				ifconfig_err_ioctlreq(lifh),
+				ifconfig_err_errno(lifh));
+		}
+		break;
+	default:
+		warnx(
+			"Should basically never end up here in this example.\n");
+		break;
+	}
+
+	ifconfig_close(lifh);
+	lifh = NULL;
+	free(ifname);
+	return (-1);
+}