udp (closure => comm closure)
udp: dict argument
- address (string list): IPv6 or IPv4 addresses to listen and send on
+ address (string list): IPv6 or IPv4 addresses to listen and send on;
+ default is all local addresses
+ port (integer): UDP port to listen and send on; optional if you
+ don't need to have a stable address for your peers to talk to
+ (in which case your site ought probably to have `local-mobile true').
+ buffer (buffer closure): buffer for incoming packets
+ authbind (string): optional, path to authbind-helper program
+
+** polypath
+
+Defines:
+ polypath (closure => comm closure)
+
+polypath: dict argument
port (integer): UDP port to listen and send on
buffer (buffer closure): buffer for incoming packets
authbind (string): optional, path to authbind-helper program
+ max-interfaces (number): optional, max number of different interfaces to
+ use (also, maximum steady-state amount of packet multiplication)
+ interfaces (string list): which interfaces to process; each entry is
+ optionally `!' or `+' followed by a glob pattern (which is applied to a
+ prospective interface using fnmatch with no flags). If no list is
+ specified, or the list ends with a `!' entry, a default list is
+ used/appended: "!tun*","!tap*","!sl*","!userv*","!lo","*". Patterns
+ which do not start with `*' or an alphanumeric need to be preceded
+ by `!' or `+'.
+ monitor-command (string list): Program to use to monitor appearance
+ and disappearance of addresses on local network interfaces. Should
+ produce lines of the form `+|-<ifname> 4|6 <addr>' where <addr> is
+ an address literal. Each - line should relate to a previously
+ printed + line. On startup, should produce a + line for each
+ currently existing address. secnet does filtering so there is no
+ need to strip out tun interfaces, multicast addresses, and so on.
+ The command is run as the user secnet is started as (not the one
+ which secnet may drop privilege to due to the configured `userid').
+ The default depends on the operating system.
+ permit-loopback (boolean): Normally, loopback IPv6 and IPv4
+ addresses on local interfaces are disregarded, because such
+ interfaces are not interesting for communicating with distant
+ hosts. Setting this option will ignore that check, which can be
+ useful for testing. Setting this option also removes "!lo*" from
+ the default interface pattern list.
+
+When using this comm, packets are sent out of every active interface
+on the host (where possible). It is important that interfaces created
+by secnet itself are not included! secnet's default filter list tries
+to do this.
+
+This comm only makes sense for sites which are mobile. That is, the
+site closures used with this comm should all have the `local-mobile'
+parameter set to `true'. When the local site site is not marked
+mobile the address selection machinery might fixate on an unsuitable
+address.
+
+For an interface to work with polypath, it must either have a suitable
+default route, or be a point-to-point interface. In the general case
+this might mean that the host would have to have multiple default
+routes. However in practice the most useful configuration is two
+interfaces being (1) wifi (2) mobile internet.
+
+I have had success on Linux by using network-manager for wifi and
+invoking ppp directly for mobile internet. ppp sets up a
+point-to-point link, and does not add a default route if there already
+is one. network-manager always sets up a default route. The result
+is that the wifi always has a default route (so is useable); ppp
+(being a point-to-point link) does not need one.
+
+The use of polypath requires that secnet be started with root
+privilege, to make the setsockopt(,,SO_BINDTODEVICE,) calls. If the
+configuration specifies that secnet should drop privilege (see
+`userid' above), secnet will keep a special process around for this
+purpose; that process will handle local network interface changes but
+does not deal with any packets, key exchange, etc.
+
+polypath support is only available when secnet is built against an
+IPv6-capable version of adns (because it wants features in the newer
+adns).
** log
~ian / secnet.git / blobdiff