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, 15 insertions, 12 deletions

diff --git a/src/lib/pb/ipcp_config.proto b/src/lib/pb/ipcp_config.proto
index a111b6d8..f6d313ac 100644
--- a/src/lib/pb/ipcp_config.proto
+++ b/src/lib/pb/ipcp_config.proto
@@ -66,29 +66,32 @@ message uni_config_msg {
         required uint32 cong_avoid     = 4;
 }
 
-message eth_config_msg {
+message eth_poa_msg {
         required string dev       = 1;
         required uint32 ethertype = 2;
+        optional bytes  mac       = 3;
 }
 
-message udp4_config_msg {
-        required uint32 ip_addr  = 1;
-        required uint32 port     = 2;
-        required uint32 dns_addr = 3; /* set to 0 if unused */
+message udp4_poa_msg {
+        required uint32 ip_addr = 1;
+        required uint32 port    = 2;
 }
 
-message udp6_config_msg {
-        required bytes  ip_addr  = 1;
-        required uint32 port     = 2;
-        required bytes  dns_addr = 3; /* set to NULL if unused */
+message udp6_poa_msg {
+        required bytes  ip_addr = 1;
+        required uint32 port    = 2;
 }
 
 
+/* Exactly one field is set; presence is the PoA type. */
+message poa_spec_msg {
+        optional udp4_poa_msg udp4 = 1;
+        optional udp6_poa_msg udp6 = 2;
+        optional eth_poa_msg  eth  = 3;
+}
+
 message ipcp_config_msg {
         required layer_info_msg layer_info =  1;
         required uint32 ipcp_type          =  2;
         optional uni_config_msg unicast    =  3;
-        optional udp4_config_msg udp4      =  4;
-        optional udp6_config_msg udp6      =  5;
-        optional eth_config_msg eth        =  6;
 }