Linux Device Drivers 3 examples

1 files changed, 84 insertions, 0 deletions

diff --git a/misc-progs/netifdebug.c b/misc-progs/netifdebug.c
new file mode 100644
index 0000000..6f0ce75
--- /dev/null
+++ b/misc-progs/netifdebug.c
@@ -0,0 +1,84 @@
+/*
+ * netifdebug.c -- change the IFF_DEBUG flag of an interface
+ *
+ * Copyright (C) 2001 Alessandro Rubini and Jonathan Corbet
+ * Copyright (C) 2001 O'Reilly & Associates
+ *
+ * The source code in this file can be freely used, adapted,
+ * and redistributed in source or binary form, so long as an
+ * acknowledgment appears in derived source files.  The citation
+ * should list that the code comes from the book "Linux Device
+ * Drivers" by Alessandro Rubini and Jonathan Corbet, published
+ * by O'Reilly & Associates.   No warranty is attached;
+ * we cannot take responsibility for errors or fitness for use.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/ioctl.h>
+#include <net/if.h>
+#include <netinet/in.h>
+
+int main(int argc, char **argv)
+{
+    int action = -1, sock;
+    struct ifreq req;
+    char *actname;
+
+    if (argc < 2) {
+        fprintf(stderr,"%s: usage is \"%s <ifname> [<on|off|tell>]\"\n",
+                argv[0],argv[0]);
+        exit(1);
+    }
+    if (argc==2)
+        actname="tell";
+    else
+        actname=argv[2];
+
+    /* a silly raw socket just for ioctl()ling it */
+    sock = socket(AF_INET, SOCK_RAW, IPPROTO_RAW);
+    if (sock < 0) {
+        fprintf(stderr, "%s: socket(): %s\n", argv[0],strerror(errno));
+        exit(1);
+    }
+
+    /* retrieve flags */
+    strcpy(req.ifr_name, argv[1]);
+    if ( ioctl(sock, SIOCGIFFLAGS, &req) < 0) {
+        fprintf(stderr, " %s: ioctl(SIOCGIFFLAGS): %s\n",
+                argv[0],strerror(errno));
+        exit(1);
+    }
+
+    if (!strcmp(actname,"on")
+        || !strcmp(actname,"+")
+        || !strcmp(actname,"1"))
+        action = IFF_DEBUG;
+
+    if (!strcmp(actname,"off")
+        || !strcmp(actname,"-")
+        || !strcmp(actname,"0"))
+        action = 0;
+
+    if (!strcmp(actname,"tell")
+        || actname[0]=='t') {
+        printf("%s: debug is %s\n", argv[1],
+               req.ifr_flags & IFF_DEBUG ? "on" : "off");
+        exit(0);
+    }
+
+    req.ifr_flags &= ~IFF_DEBUG;
+    req.ifr_flags |= action;
+
+    if ( ioctl(sock, SIOCSIFFLAGS, &req) < 0) {
+        fprintf(stderr, " %s: ioctl(SIOCSIFFLAGS): %s\n",
+                argv[0],strerror(errno));
+        exit(1);
+    }
+    exit(0);
+}