On a Windows machine I have a VLAN capable Network Card. When the (Intel) driver is configured for VLAN use the windows control panel shows a network interface for each vlan. Programs using sockets are unaffected.
In the lwip contect the netif structure at the equivalent level to the Windows netowrk interface. I think this means that there is a possible vlan output implementation for lwip based on adding vlan/qos info to netif without any socket changes. Below the socket level it will be necessary to locate the correct netif to use for output. I would expect different vlans to be using different subnets so ip routing can determine which netif to use using destination ip address. Brian -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: 08 November 2011 20:06 To: Mailing list for lwIP users Subject: Re: [lwip-users] Add support for outgoing VLAN tags? [email protected] wrote: > Yes, it is. It is a mandatory feature for certain protocols, such as > the industrial control protocol "EtherNet/IP" > http://en.wikipedia.org/wiki/Ethernet/IP That's interesting. Since I know of at least one Ethernet/IP stack being ported to linux, do you know whether/how linux allows changing the VLAN header per socket? > The problem with adding VLAN PCP to LwIP is that a socket level > variable must somehow be communicated down to the link layer for each > frame. There does not seem to be a easy way of doing this. Thinkig about it, we already have a mechanism for that: the per-pcb ARP entry cache. In the same manner as this, we could add members to struct netif which configure VLAN settings and change them before calling one of the ip_output functions (although that set/reset code would be scattered around tcp, udp, raw, icmp and igmp). Simon _______________________________________________ lwip-users mailing list [email protected] https://lists.nongnu.org/mailman/listinfo/lwip-users ********************************************************************** This e-mail from Ultra Electronics Limited and any attachments to it are confidential to the intended recipient and may also be privileged. If you have received it in error please notify the sender and delete it from your system. If you are not the intended recipient you must not copy it or use it for any purpose nor disclose or distribute its contents to any other person. All communications may be subject to interception or monitoring for operational and/or security purposes. Please rely on your own virus checking as the sender cannot accept any liability for any damage arising from any bug or virus infection. Ultra Electronics Limited is a company registered in England and Wales, registration number 2830644. The address of its registered office is 417 Bridport Road, Greenford, Middlesex, UB6 8UA. ********************************************************************** _______________________________________________ lwip-users mailing list [email protected] https://lists.nongnu.org/mailman/listinfo/lwip-users
