Provided by: rdma-core_42.0-1_amd64 bug


       iwpmd - port mapping services for iWARP.




       The  iWARP  Port Mapper Daemon provides a user space service (iwpmd) for the iWarp drivers
       to claim tcp ports through the standard socket interface.

       The kernel space support for the port mapper is part of the  iw_cm  module.   The  ib_core
       module  includes  netlink  support,  which  is used by the port mapper clients to exchange
       messages with iwpmd. Both modules iw_cm and ib_core need to be loaded  in  order  for  the
       libiwpm service to start successfully.


       The  iWARP Port Mapper implementation is based on the port mapper specification section in
       the Sockets Direct Protocol:

       Existing  iWARP  RDMA  providers  use  the same IP address as the native TCP/IP stack when
       creating RDMA connections.  They need a mechanism to claim the TCP  ports  used  for  RDMA
       connections  to  prevent  TCP  port collisions when other host applications use TCP ports.
       The iWARP Port Mapper provides a standard mechanism  to  accomplish  this.   Without  this
       service  it  is  possible  for  RDMA  application to bind/listen on the same port which is
       already being used by native TCP host application.   If  that  happens  the  incoming  TCP
       connection data can be passed to the RDMA stack with error.

       The  iWARP  Connection Manager (port mapper client) sends to the IWPM service the local IP
       address and TCP  port  it  has  received  from  the  RDMA  application,  when  starting  a
       connection.   The  IWPM service performs a socket bind from user space to get an available
       TCP port, called a mapped port, and communicates it back to the client.   In  that  sense,
       the  IWPM service is used to map the TCP port, which the RDMA application uses to any port
       available from the host  TCP  port  space.  The  mapped  ports  are  used  in  iWARP  RDMA
       connections  to avoid collisions with native TCP stack which is aware that these ports are
       taken. When an RDMA connection using a mapped port is terminated, the client notifies  the
       IWPM service, which then releases the TCP port.

       The  message  exchange  between iwpmd and the iWARP Connection Manager (between user space
       and kernel space) is implemented using netlink sockets.


       -s, --systemd Enable systemd integration.


       SIGUSR1 will force a dump of the current mappings to the system message log.

       SIGTERM/SIGHUP will force iwpmd to exit.