JeepGuy
asked on
How do I specify/bind a socket to a specific NIC?
I'm trying to configure multiple sockets in one app and have them bound to specific addresses & NICs. I have one TCP socket setup on one address, but I need to set up a separate UDP socket for broadcasting to use a completely different address configured on the other NIC. I can't seem to specify the UDP socket to send FROM the second NIC. I've done the....
send_struct.sin_family = AF_INET;
send_struct.sin_addr.s_add
bind(my_udp_socket, (SOCKADDR*) &send_struct, sizeof(send_struct));
...where NIC 1 is 192.168.1.10 and NIC 2 is 164.217.14.10 (mask: 255.255.0.0)
But, that doesn't seem to do it. When I call my sendto() function.....
send_struct.sin_port = htons("3000");
send_struct.sin_addr.s_add
sendto(my_udp_socket, (int8 *)pkt, len, 0, (const struct sockaddr *)&send_struct, sizeof(send_struct));
...I don't see it show up on the wire (and the return value from sendto() returns the number of bytes I'm sending and I'm connected to an actual hub, not a switch...thus Wireshark shows everything). I've searched for an example on someone setting up multiple socket connections bound to different NICs/subnets and haven't found a solution that works yet. Any ideas?
send_struct.sin_family = AF_INET;
send_struct.sin_addr.s_add
bind(my_udp_socket, (SOCKADDR*) &send_struct, sizeof(send_struct));
...where NIC 1 is 192.168.1.10 and NIC 2 is 164.217.14.10 (mask: 255.255.0.0)
But, that doesn't seem to do it. When I call my sendto() function.....
send_struct.sin_port = htons("3000");
send_struct.sin_addr.s_add
sendto(my_udp_socket, (int8 *)pkt, len, 0, (const struct sockaddr *)&send_struct, sizeof(send_struct));
...I don't see it show up on the wire (and the return value from sendto() returns the number of bytes I'm sending and I'm connected to an actual hub, not a switch...thus Wireshark shows everything). I've searched for an example on someone setting up multiple socket connections bound to different NICs/subnets and haven't found a solution that works yet. Any ideas?
ASKER
I have already set up two different sockaddr_in structs for the different sockets. I even tried using one for the bind and another for the sendto() func for the same socket.
sounds awful
oh, i did notice (forgot to add it to my first comment)
sin_addr.s_addr = inet_addr("IP")
your second sin_addr.s_addr= does not have the inet_addr - not sure if you wanted it like that or not.
I have referenced this page (http://www.linuxhowtos.org/C_C++/socket.htm) many times in the past; what I would to is start a test project for yourself, with binding to two unique IP:Port's and exporting that working code to your project, so that you dont overwhelm yourself in your full sized project.
oh, i did notice (forgot to add it to my first comment)
sin_addr.s_addr = inet_addr("IP")
your second sin_addr.s_addr= does not have the inet_addr - not sure if you wanted it like that or not.
I have referenced this page (http://www.linuxhowtos.org/C_C++/socket.htm) many times in the past; what I would to is start a test project for yourself, with binding to two unique IP:Port's and exporting that working code to your project, so that you dont overwhelm yourself in your full sized project.
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I dont think it matters much, but in code i've written, my sendto does not use (const struct sockaddr *), but rather, (struct sockaddr *)