cvs commit: src/sys/kern uipc_socket.c uipc_usrreq.c src/sys/netatm atm_cm.c atm_socket.c atm_var.h src/sys/netgraph/bluetooth/socket ng_btsocket_l2cap.c ng_btsocket_rfcomm.c src/sys/netinet ...

[Robert Watson]

rwatson     2005-03-07 13:08:05 UTC

  FreeBSD src repository

  Modified files:        (Branch: RELENG_5)
    sys/kern             uipc_socket.c uipc_usrreq.c 
    sys/netatm           atm_cm.c atm_socket.c atm_var.h 
    sys/netatm/ipatm     ipatm_load.c 
    sys/netgraph/bluetooth/socket ng_btsocket_l2cap.c 
                                  ng_btsocket_rfcomm.c 
    sys/netinet          tcp_usrreq.c 
    sys/netipx           spx_usrreq.c 
    sys/sys              socketvar.h 
  Log:
  Merge uipc_socket.c:1.233, uipc_usrreq.c:1.151, atm_cm.c:1.33,
  atm_socket.c:1.23, atm_var.h:1.26, ipatm_load.c:1.l21,
  ng_btsocket_l2cap.c:1.16, ng_btsocket_rfcomm.c:1.15, tcp_usrreq.c:1.15,
  spx_usrreq.c:1.62, socketvar.h:1.139 from HEAD to RELENG_5:
  
    In the current world order, solisten() implements the state transition of
    a socket from a regular socket to a listening socket able to accept new
    connections.  As part of this state transition, solisten() calls into the
    protocol to update protocol-layer state.  There were several bugs in this
    implementation that could result in a race wherein a TCP SYN received
    in the interval between the protocol state transition and the shortly
    following socket layer transition would result in a panic in the TCP code,
    as the socket would be in the TCPS_LISTEN state, but the socket would not
    have the SO_ACCEPTCONN flag set.
  
    This change does the following:
  
    - Pushes the socket state transition from the socket layer solisten() to
      to socket "library" routines called from the protocol.  This permits
      the socket routines to be called while holding the protocol mutexes,
      preventing a race exposing the incomplete socket state transition to TCP
      after the TCP state transition has completed.  The check for a socket
      layer state transition is performed by solisten_proto_check(), and the
      actual transition is performed by solisten_proto().
  
    - Holds the socket lock for the duration of the socket state test and set,
      and over the protocol layer state transition, which is now possible as
      the socket lock is acquired by the protocol layer, rather than vice
      versa.  This prevents additional state related races in the socket
      layer.
  
    This permits the dual transition of socket layer and protocol layer state
    to occur while holding locks for both layers, making the two changes
    atomic with respect to one another.  Similar changes are likely require
    elsewhere in the socket/protocol code.
  
    Reported by:            Peter Holm <peter at holm.cc>
    Review and fixes from:  emax, Antoine Brodin <antoine.brodin at laposte.net>
    Philosophical head nod: gnn
  
  Note that this changes the behavior of the pru_listen() protocol entry point;
  all protocols are updated to match the new behavior.  We do not know of any
  third party protocol implementations that this might cause problems for.
  
  Approved by:    re (kensmith)
  
  Revision    Changes    Path
  1.208.2.17  +42 -14    src/sys/kern/uipc_socket.c
  1.138.2.13  +14 -9     src/sys/kern/uipc_usrreq.c
  1.31.4.2    +13 -1     src/sys/netatm/atm_cm.c
  1.20.2.3    +1 -1      src/sys/netatm/atm_socket.c
  1.24.4.2    +2 -2      src/sys/netatm/atm_var.h
  1.19.4.2    +2 -2      src/sys/netatm/ipatm/ipatm_load.c
  1.13.2.3    +21 -6     src/sys/netgraph/bluetooth/socket/ng_btsocket_l2cap.c
  1.12.2.3    +25 -19    src/sys/netgraph/bluetooth/socket/ng_btsocket_rfcomm.c
  1.107.2.2   +14 -4     src/sys/netinet/tcp_usrreq.c
  1.46.2.13   +7 -2      src/sys/netipx/spx_usrreq.c
  1.133.2.4   +2 -0      src/sys/sys/socketvar.h