Changes between Initial Version and Version 1 of TBR/UserManual/Obtaining_Interface_Information

Timestamp:

04/04/08 14:06:35 (16 years ago)

Author:

Vdcappel

Comment:

Conversion from e-mail introduced some spurious 's in the code

TBR/UserManual/Obtaining_Interface_Information

@@ +1 @@
+= Obtaining Interface Information =
+
+
+This is based on an answer posted to the RTEMS User's mailing list by [wiki:ThomasRauscher ThomasRauscher] http://www.rtems.com/ml/rtems-users/2004/november/msg00255.html.
+
+
+'''Question:''' What is the best way to obtain my IP address, MAC Address, Network Mask, and Default Gateway after the
+''rtems''bsdnet''initialize''network()_ call?  I want to be able to access this information from software.
+
+
+'''Answer:'''  This should do the trick. 'ifname' should contain the name of your interface, e.g. "eth0", 'addr' then contains the result.
+
+
+{{{
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <net/if.h>
+#include <netinet/in.h>
+
+int get_ifaddr(const char *ifname, struct in_addr *addr)
+{
+    int fd;
+    int rc;
+    struct ifreq ifreq;
+    struct sockaddr_in *sockaddr;
+
+    fd = socket(AF_INET, SOCK_DGRAM, 0);
+    if(fd<0) {
+        return -1;
+    }
+
+    strcpy(ifreq.ifr_name, ifname);
+
+    rc = ioctl(fd, SIOCGIFADDR, &ifreq);
+    if(rc == 0)
+    {
+        sockaddr = (struct sockaddr_in *) &ifreq.ifr_ifru.ifru_addr;
+        memcpy(addr, &sockaddr->sin_addr, sizeof(*addr));
+    }
+
+    close(fd);
+    return (rc==0) ? 0 : -1;
+}
+}}}