to a non-wildcard address. As documented in ip(4), doing sendmsg(2) with
IP_SENDSRCADDR on a socket that is bound to non-wildcard address is
completely different to using this control message on a wildcard one.
A fix is to add a bool to mark whether we did setsockopt(IP_RECVDSTADDR)
on the socket, and use IP_SENDSRCADDR control message only if we did.
While here, garbage collect absolutely useless udp_recv() function that
establishes some structures on stack to never use them later.
as the listening address in snmpd_input(..)
Stash the IPv4 address of the receiver via the recv(..) callback and use it in
the send(..) callback for the transport by specifying IP_SENDSRCADDR for the
control message type.
Add sendmsg logic to the UDP transport's send(..) callback and use the
respective send(..) callback for the transport instead of calling sendto in
snmpd_input(..).
MFC after: 3 weeks
Obtained from: Isilon OneFS (^/onefs/branches/BR_8_0_0_DEV@r507595)
Submitted by: Thor Steingrimsson <thor.steingrimsson@isilon.com>
Sponsored by: Dell EMC Isilon
