lib: Replace shim IPCPs with points of attachment

Removes the UDP and Ethernet shim IPCPs. The unicast and broadcast
IPCPs can now directly attach to a "legacy" socket. We adopt Saltzer's
Point-of-Attachment terminology, also advocated in Day's "Patterns in
Network Architecture". The "poa" component manages these
PoA's with one management thread, one link monitoring thread and one
thread per attached point.

For Ethernet PoA's the irm connect and enroll can resolve the
destination IPCP or Layer name with a broadcast name query over the
attached PoAs (first reply wins). UDP PoA's require a destination IP
address or FQDN.

attach to a local endpoint (required both server and client side):

 irm ipcp poa attach name a udp 10.0.0.1
 irm ipcp poa attach name a udp 10.0.0.1:3435
 irm ipcp poa attach name a udp [::1]:3435
 irm ipcp poa attach name a eth dev eth0
 irm ipcp poa attach name a eth dev eth0 ethertype 0xA000

release a PoA (refused while it carries a flow):

 irm ipcp poa detach name a udp 10.0.0.1:3435
 irm ipcp poa detach name a eth eth0

list an IPCP's PoAs:

 irm ipcp poa list name a

connect to a peer, by name or at an address:

 irm ipcp connect name b dst a
 irm ipcp connect name b dst a eth
 irm ipcp connect name b dst a eth dev eth0
 irm ipcp connect name b dst a udp 10.0.0.1:3435
 irm ipcp connect name b dst a udp peer.example.com:3435

disconnect by peer name, no address:

 irm ipcp disconnect name b dst a
 irm ipcp disconnect name b dst a component mgmt

enroll has the same shape as connect:

 irm ipcp enroll name b layer lr autobind
 irm ipcp enroll name b layer lr autobind eth dev eth0
 irm ipcp enroll name b layer lr autobind udp 10.0.0.1:3435

the IRMd config file attaches PoAs and names peers the same way:

 udp = [ "10.0.0.1", "10.0.0.1:3436" ]
 eth = [ "eth0", {dev="eth1", ethertype=0xA007} ]

 enrol={dst="LAN", eth={dev="eth0"}}
 conn=[{dst="lan3", eth={}}, {dst="lan4", udp="10.0.0.1:3435"}]

Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks>
Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>

1 files changed, 37 insertions, 0 deletions

diff --git a/cmake/config/lib/poa.cmake b/cmake/config/lib/poa.cmake
new file mode 100644
index 00000000..c1ca10a8
--- /dev/null
+++ b/cmake/config/lib/poa.cmake
@@ -0,0 +1,37 @@
+# Flow Point of attachment (poa) configuration for Ouroboros
+
+set(POA_MGMT_FRAME_SIZE 16384 CACHE STRING
+  "Maximum size of a flow endpoint management frame, in bytes")
+
+# Management frames are retried or repeated, so a send never waits long.
+set(POA_MGMT_SND_TIMEO 100 CACHE STRING
+  "Deadline for sending a management frame, in ms")
+
+# Flows on one PoA share its transmit queue, so congestion avoidance keys its link estimator on the
+# PoA and needs a bound on their number.
+set(POA_MAX_POAS 16 CACHE STRING
+  "Maximum number of points of attachment per IPCP")
+
+# UDP endpoints
+set(POA_UDP_MPL 5000 CACHE STRING
+  "Default maximum packet lifetime for UDP flow endpoints, in ms")
+set(POA_UDP4_MTU 1472 CACHE STRING
+  "Fallback UDP4 endpoint MTU when getsockopt(IP_MTU) is unavailable")
+set(POA_UDP6_MTU 1452 CACHE STRING
+  "Fallback UDP6 endpoint MTU when getsockopt(IPV6_MTU) is unavailable")
+set(POA_UDP_RD_BUF 65535 CACHE STRING
+  "UDP endpoint receive buffer in bytes. Bounds the advertised MTU")
+
+# Ethernet endpoints
+set(POA_ETH_MPL 100 CACHE STRING
+  "Default maximum packet lifetime for Ethernet flow endpoints, in ms")
+set(POA_ETH_QDISC_BYPASS false CACHE BOOL
+  "Bypass the Qdisc in the kernel when using raw sockets")
+set(POA_ETH_SNDBUF 0 CACHE STRING
+  "Raw socket SO_SNDBUF in bytes (floored to one frame). 0 = kernel default")
+set(POA_ETH_RCVBUF 0 CACHE STRING
+  "Raw socket SO_RCVBUF in bytes. 0 = kernel default")
+set(POA_ETH_LO_MTU 9000 CACHE STRING
+  "Restrict Ethernet flow endpoint MTU over loopback interfaces")
+set(POA_ETH_RD_BUF 16384 CACHE STRING
+  "Cap on the Ethernet endpoint receive buffer and MTU, in bytes")