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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'>Hi,<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'>I have written a sample code to modify the link-local address of an Ethernet interface.<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'>The code snippet is – <o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> while(1) {<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> printf("\n1.Add Link Local\n2.Modify LinkLocal\n”);<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> scanf("%d", &ch);<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> switch(ch) {<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> case 1:<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> {<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> add_linklocaladdr(fd, NLM_F_CREATE|NLM_F_EXCL);<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> break;<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> }<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> case 2:<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> {<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> add_linklocaladdr(fd, NLM_F_REPLACE);<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> break;<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> }<o:p></o:p></span></p><p class=MsoNormal style='text-indent:.5in'><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> -------------<o:p></o:p></span></p><p class=MsoNormal style='text-indent:.5in'><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> -------------<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'>void add_linklocaladdr(int fd, int flags)) {<o:p></o:p></span></p><p class=MsoNormal style='text-indent:.5in'><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'>-------------<o:p></o:p></span></p><p class=MsoNormal style='text-indent:.5in'><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> -------------<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> nlh = (struct nlmsghdr *)buf;<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> len = MSG_ALIGN(sizeof(struct nlmsghdr));<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> nlh->nlmsg_len = len;<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> nlh->nlmsg_type = RTM_NEWADDR;<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> nlh->nlmsg_flags = NLM_F_REQUEST | flag;<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> nlh->nlmsg_seq = 1;<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> ifadr = nlmsg_put_extra_header(nlh, sizeof(struct ifaddrmsg));<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> ifadr->ifa_family = AF_INET6;<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> ifadr->ifa_prefixlen = 0x40 ; /*hardcoded*/<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> ifadr->ifa_flags = IFA_F_PERMANENT;;<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> ifadr->ifa_scope = RT_SCOPE_HOST;<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> ifadr->ifa_index = 2;<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> /*Push ‘struct nlattr’ */<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'> attr_put(nlh, IFA_ADDRESS, dst);<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'>When I execute case 1 (add link-local), a new ipv6 ip is getting added.<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'>I want to modify an existing link local address in case2, but it’s not working.<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'>Can anybody help me correcting this code for case2.<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#002060'>Thanks & Regards<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#002060'>Murali Annamneni</span><span style='color:#17365D'><o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p></div><span style="FONT-FAMILY: 'Arial','sans-serif'; 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