doc: start translating user manual to rst

Automatically translated all Texinfo files to RST using a script found
on the GCC mailing list[0]. Some formatting manually corrected.

Also created index.rst for building as well as boilerplate Sphinx
conf.py and Makefile.

[0] https://gcc.gnu.org/ml/gcc-patches/2015-11/msg01095.html

Signed-off-by: Quentin Young <qlyoung@cumulusnetworks.com>

1 files changed, 153 insertions, 0 deletions

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+.. _NHRP:
+
+****
+NHRP
+****
+
+*nhrpd* is a daemon to support Next Hop Routing Protocol (NHRP).
+NHRP is described in RFC2332.
+
+NHRP is used to improve the efficiency of routing computer network
+traffic over Non-Broadcast, Multiple Access (NBMA) Networks. NHRP provides
+an ARP-like solution that allows a system to dynamically learn the NBMA
+address of the other systems that are part of that network, allowing
+these systems to directly communicate without requiring traffic to use
+an intermediate hop.
+
+Cisco Dynamic Multipoint VPN (DMVPN) is based on NHRP, and
+@value{PACKAGE_NAME} nhrpd implements this scenario.
+
+.. _Routing_Design:
+
+Routing Design
+==============
+
+nhrpd never handles routing of prefixes itself. You need to run some
+real routing protocol (e.g. BGP) to advertise routes over the tunnels.
+What nhrpd does it establishes 'shortcut routes' that optimizes the
+routing protocol to avoid going through extra nodes in NBMA GRE mesh.
+
+nhrpd does route NHRP domain addresses individually using per-host prefixes.
+This is similar to Cisco FlexVPN; but in contrast to opennhrp which uses
+a generic subnet route.
+
+To create NBMA GRE tunnel you might use the following (linux terminal
+commands):
+::
+
+  @group
+   ip tunnel add gre1 mode gre key 42 ttl 64
+   ip addr add 10.255.255.2/32 dev gre1
+   ip link set gre1 up
+  @end group
+  
+
+Note that the IP-address is assigned as host prefix to gre1. nhrpd will
+automatically create additional host routes pointing to gre1 when
+a connection with these hosts is established.
+
+The gre1 subnet prefix should be announced by routing protocol from the
+hub nodes (e.g. BGP 'network' announce). This allows the routing protocol
+to decide which is the closest hub and determine the relay hub on prefix
+basis when direct tunnel is not established.
+
+nhrpd will redistribute directly connected neighbors to zebra. Within
+hub nodes, these routes should be internally redistributed using some
+routing protocol (e.g. iBGP) to allow hubs to be able to relay all traffic.
+
+This can be achieved in hubs with the following bgp configuration (network
+command defines the GRE subnet):
+::
+
+  @group
+  router bgp 65555
+   address-family ipv4 unicast
+     network 172.16.0.0/16
+     redistribute nhrp
+   exit-address-family
+  @end group
+  
+
+.. _Configuring_NHRP:
+
+Configuring NHRP
+================
+
+FIXME
+
+.. _Hub_Functionality:
+
+Hub Functionality
+=================
+
+In addition to routing nhrp redistributed host prefixes, the hub nodes
+are also responsible to send NHRP Traffic Indication messages that
+trigger creation of the shortcut tunnels.
+
+nhrpd sends Traffic Indication messages based on network traffic captured
+using NFLOG. Typically you want to send Traffic Indications for network
+traffic that is routed from gre1 back to gre1 in rate limited manner.
+This can be achieved with the following iptables rule.
+
+::
+
+  @group
+  iptables -A FORWARD -i gre1 -o gre1 \\
+  	-m hashlimit --hashlimit-upto 4/minute --hashlimit-burst 1 \\
+  	--hashlimit-mode srcip,dstip --hashlimit-srcmask 24 --hashlimit-dstmask 24 \\
+  	--hashlimit-name loglimit-0 -j NFLOG --nflog-group 1 --nflog-range 128
+  @end group
+  
+
+You can fine tune the src/dstmask according to the prefix lengths you
+announce internal, add additional IP range matches, or rate limitation
+if needed. However, the above should be good in most cases.
+
+This kernel NFLOG target's nflog-group is configured in global nhrp config
+with:
+::
+
+  @group
+  nhrp nflog-group 1
+  @end group
+  
+
+To start sending these traffic notices out from hubs, use the nhrp
+per-interface directive:
+::
+
+  @group
+  interface gre1
+   ip nhrp redirect
+  @end group
+  
+
+.. _Integration_with_IKE:
+
+Integration with IKE
+====================
+
+nhrpd needs tight integration with IKE daemon for various reasons.
+Currently only strongSwan is supported as IKE daemon.
+
+nhrpd connects to strongSwan using VICI protocol based on UNIX socket
+(hardcoded now as /var/run/charon.vici).
+
+strongSwan currently needs few patches applied. Please check out the
+`http://git.alpinelinux.org/cgit/user/tteras/strongswan/log/?h=tteras-release,release <http://git.alpinelinux.org/cgit/user/tteras/strongswan/log/?h=tteras-release,release>`_
+and
+`http://git.alpinelinux.org/cgit/user/tteras/strongswan/log/?h=tteras,working tree <http://git.alpinelinux.org/cgit/user/tteras/strongswan/log/?h=tteras,working tree>`_
+git repositories for the patches.
+
+.. _NHRP_Events:
+
+NHRP Events
+===========
+
+FIXME
+
+Configuration Example
+=====================
+
+FIXME
+