connection: Add 'add-socket-membership'.

Ludovic Court??sTue May 23 20:45:20+0200 2023

d6aa16d

connection: Add 'add-socket-membership'. * netlink/connection.scm (socklen_t, ffi-setsockopt, SOL_NETLINK) * netlink/connection.scm (NETLINK_ADD_MEMBERSHIP) (NETLINK_DROP_MEMBERSHIP, NETLINK_PKTINFO) (NETLINK_BROADCAST_ERROR, NETLINK_NO_ENOBUFS) (NETLINK_LISTEN_ALL_NSID, NETLINK_LIST_MEMBERSHIPS) (NETLINK_CAP_ACK, NETLINK_EXT_ACK, NETLINK_GET_STRICT_CHK): New variables. (add-socket-membership): New procedure. * netlink/constant.scm (int->rtnetlink-group): New enum. * doc/guile-netlink.texi (Netlink Connections): Document it. Signed-off-by: Julien Lepiller <julien@lepiller.eu>

doc/guile-netlink.texi

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to the @code{socket} system call---e.g., @code{SOCK_NONBLOCK}.
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@end deffn
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@cindex subscribing, to an rtnetlink group
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@deffn {Scheme Procedure} add-socket-membership @var{sock} @var{group}
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Make @var{sock} a member of @var{group}, an @code{RTNLGRP_} constant,
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meaning that it will be subscribed to events of that group.
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For example, here is how you could create a netlink socket and subscribe
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it to the ``link'' group so that it receives notifications for new and
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removed links:
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@lisp
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(let ((sock (connect-route)))
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  (add-socket-membership sock RTNLGRP_LINK)
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  @dots{})
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@end lisp
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This procedure is implemented as a @code{setsockopt} call.
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@end deffn
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@deffn {Scheme Procedure} send-msg @var{msg} @var{sock} [#:@var{addr}]
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Send @var{msg} (it must be of type message, @xref{Netlink Headers}) to
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@var{addr} using @var{sock}.  If not passed, @var{addr} is the address of
netlink/connection.scm
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                                          current-write-waiter)
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  #:export (connect
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            connect-route
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            add-socket-membership
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            close-socket
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            send-msg
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            receive-msg
…
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  (syscall->procedure int "bind" (list int '* int)
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                      #:waiter (lambda () (current-read-waiter))))
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(define socklen_t uint32)                         ;per <posix/bits/types.h>
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(define ffi-setsockopt
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  (syscall->procedure int "setsockopt" (list int int int '* socklen_t)))
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(define SOL_NETLINK 270)
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(define NETLINK_ADD_MEMBERSHIP 1)
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(define NETLINK_DROP_MEMBERSHIP 2)
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(define NETLINK_PKTINFO 3)
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(define NETLINK_BROADCAST_ERROR 4)
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(define NETLINK_NO_ENOBUFS 5)
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(define NETLINK_LISTEN_ALL_NSID 8)
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(define NETLINK_LIST_MEMBERSHIPS 9)
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(define NETLINK_CAP_ACK 10)
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(define NETLINK_EXT_ACK 11)
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(define NETLINK_GET_STRICT_CHK 12)
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;; define simple functions to open/close sockets
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(define (open-socket proto flags)
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  (socket AF_NETLINK (logior SOCK_RAW SOCK_CLOEXEC flags) proto))
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(define (add-socket-membership sock group)
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  "Make @var{sock} a member of @var{group}, an @code{RTNLGRP_} constant,
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meaning that it will be subscribed to events of that group."
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  (let ((bv (make-bytevector (sizeof int))))
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    (bytevector-uint-set! bv 0 group (native-endianness) (sizeof int))
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    (ffi-setsockopt sock SOL_NETLINK NETLINK_ADD_MEMBERSHIP
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                    (bytevector->pointer bv) (bytevector-length bv))))
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(define (close-socket sock)
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  (issue-deprecation-warning
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   "'close-socket' is deprecated; use 'close-port' instead.")
netlink/constant.scm
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(define-enum int->link-type
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  (ARPHRD_ETHER 1)
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  (ARPHRD_LOOPBACK 772))
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;; enum rtnetlink_groups
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(define-enum int->rtnetlink-group
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  (RTNLGRP_NONE 0)
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  RTNLGRP_LINK
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  RTNLGRP_NOTIFY
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  RTNLGRP_NEIGH
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  RTNLGRP_TC
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  RTNLGRP_IPV4_IFADDR
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  RTNLGRP_IPV4_MROUTE
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  RTNLGRP_IPV4_ROUTE
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  RTNLGRP_IPV4_RULE
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  RTNLGRP_IPV6_IFADDR
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  RTNLGRP_IPV6_MROUTE
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  RTNLGRP_IPV6_ROUTE
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  RTNLGRP_IPV6_IFINFO
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  RTNLGRP_DECnet_IFADDR
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  RTNLGRP_NOP2
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  RTNLGRP_DECnet_ROUTE
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  RTNLGRP_DECnet_RULE
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  RTNLGRP_NOP4
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  RTNLGRP_IPV6_PREFIX
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  RTNLGRP_IPV6_RULE
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  RTNLGRP_ND_USEROPT
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  RTNLGRP_PHONET_IFADDR
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  RTNLGRP_PHONET_ROUTE
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  RTNLGRP_DCB
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  RTNLGRP_IPV4_NETCONF
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  RTNLGRP_IPV6_NETCONF
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  RTNLGRP_MDB
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  RTNLGRP_MPLS_ROUTE
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  RTNLGRP_NSID
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  RTNLGRP_MPLS_NETCONF
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  RTNLGRP_IPV4_MROUTE_R
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  RTNLGRP_IPV6_MROUTE_R
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  RTNLGRP_NEXTHOP
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  RTNLGRP_BRVLAN
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  RTNLGRP_MCTP_IFADDR
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  RTNLGRP_TUNNEL
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  RTNLGRP_STATS)