On Thu, Dec 29, 2016 at 04:38:05PM -0200, Till Kamppeter wrote: > On 12/29/2016 04:31 PM, Stéphane Graber wrote: > > On Thu, Dec 29, 2016 at 04:14:52PM -0200, Till Kamppeter wrote: > > > On 12/29/2016 02:37 PM, Stéphane Graber wrote: > > > > > How can I assign a different name to a dummy interface? Can I freely > > > > > choose > > > > > a name somehow, for example "ippusbxd"? Or have I to use "dummy1", > > > > > "dummy2", > > > > > ... (loading the dummy kernel module with an option to support more > > > > > than one > > > > > interface)? > > > > > > > > root@castiana:~# ip link add ippusbxd type dummy > > > > root@castiana:~# ip link set ippusbxd up > > > > root@castiana:~# ifconfig ippusbxd > > > > ippusbxd: flags=195<UP,BROADCAST,RUNNING,NOARP> mtu 1500 > > > > inet6 fe80::3004:2dff:feb6:b5c7 prefixlen 64 scopeid > > > > 0x20<link> > > > > ether 32:04:2d:b6:b5:c7 txqueuelen 1000 (Ethernet) > > > > RX packets 0 bytes 0 (0.0 B) > > > > RX errors 0 dropped 0 overruns 0 frame 0 > > > > TX packets 2 bytes 140 (140.0 B) > > > > TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 > > > > > > > > > > > > Which gets you your own dummy device with its IPv6 link-local address. > > > > > > Thank you very much. I copied and pasted the commands and got an ifconfig > > > output similar to yours, only with different IP and MAC addresses and > > > different values in the statistics. > > > > > > Then I tried to bind to the IPv6 IP address of this entry, on port 60000 > > > and > > > this did not work. > > > > > > Do I have to create an additional IP address? If yes, how? Do I have to > > > run > > > additional commands (route?)? Which ones? > > > > > > Till > > > > Link-local addresses are slightly special in that they are indeed link > > local. > > > > So you can't bind fe80::3004:2dff:feb6:b5c7 as you could in theory have > > the same address on multiple interfaces. Instead, you need to tell > > bind() what interface to bind on. This is typically indicated as > > fe80::3004:2dff:feb6:b5c7%ippusbxd. > > > > > > For example: > > > > stgraber@castiana:~$ nc -l fe80::3004:2dff:feb6:b5c7 1234 > > nc: Invalid argument > > > > ^ Fails because the kernel doesn't know what interface you want. > > > > stgraber@castiana:~$ nc -l fe80::3004:2dff:feb6:b5c7%ippusbxd 1234 > > > > ^ Works > > > > Thank you. I want to bind with the bind(2) function in C. How do I supply > the interface here or what function do I need to call instead? > > Till
#include <arpa/inet.h>
#include <net/if.h>
int main(int argc, char *argv[])
{
int s;
struct sockaddr_in6 ip6;
// Basic inet6 socket
s = socket(AF_INET6, SOCK_DGRAM, 0);
// Initialize the ip6 struct
ip6.sin6_family=AF_INET6;
ip6.sin6_addr=in6addr_any;
ip6.sin6_port=htons(1234);
ip6.sin6_scope_id=if_nametoindex("ippusbxd");
inet_pton(AF_INET6, "fe80::3004:2dff:feb6:b5c7", (void
*)&ip6.sin6_addr.s6_addr);
// Bind
bind(s, (struct sockaddr *)&ip6, sizeof(struct sockaddr_in6));
}
--
Stéphane Graber
Ubuntu developer
http://www.ubuntu.com
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