[lwip-users] udp_recv: read destination address

[chrysn]

hello lwip fellow users,

updating the libcoap library's lwip port, i'll need to know which
network address the package i'm just udp_recv'ing was sent to. (this is
a requirement of rfc7252, which has sections that only apply if the
receiving address is a multicast address).

has there been any change on this subject since 2006[1]?

if not, the options i see are, in decreasing order of preference

* have a dedicated udp_recv_extended mechanism in parallel to udp_recv.
  if an extended recv is set, the package will go there, otherwise it
  goes to the classical recv.

  no api change, and the additional pointer per pcb can be made optional
  at compile time.

* just extend the recv callback (all udp users must change)

* use some obsucre way to allow both forms on the same callback,
  possibly by casting around function pointers to make their argument
  counts match and relying on the abi to not have such tricks go wrong.

would a patch implementing the first option be acceptable?


best regards
chrysn

[1] https://www.mail-archive.com/address@hidden/msg01483.html

signature.asc
Description: Digital signature