[lwip-devel] [bug #3168] Handling UDP/TCP PCBs upon netif address change.

[Simon Goldschmidt]

Follow-up Comment #12, bug #3168 (project lwip):

>From experimentation on Linux, trying it out with a UDP socket, send() gets
EINVAL if the local IP address that had been bound gets changed.

We can get that by including a check in udp_send() that checks if the
local_ip of the udp pcb (if not is_any) is the same as the ip_addr of the
netif used to send the packet (if not, we return ERR_VAL).

If we then send to the socket/netconn, we get an error ERR_VAL into conn->err
(do_send() has to be modified to catch more errors, see task #6880) that is
translated to EINVAL.

See attached patch for this.

The receive side, however, sits there and waits since there is no new packet
delivered. Jonathan, can you check on linux what happens calling recv() on
such a socket? Or what happens if, during a blocking recv() call, the ip
address gets changed?

(file #12764)
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Additional Item Attachment:

File name: udp_check_local_ip_on_send.patch Size:2 KB


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