build: Refactor CMake back to in-tree CMakeListsbe

This moves the build definitions back to src/ subdirectories
(CMakeLists.txt per component). Configuration and dependencies are
kept out of tree. Configuration options are bundled into cmake/config/
modules. Dependencies are grouped by component (system/, crypt/, eth/,
coverage/, etc.). It now consistently uses target-based commands
(target_include_directories, target_link_libraries) instead of global
include_directories(). Proper PRIVATE/PUBLIC visibility for executable
link libraries. CONFIG_OUROBOROS_DEBUG now properly set based on being
a valid debug config (not just checking the string name).

It also adds OuroborosTargets export for find_package() support and
CMake package config files (OuroborosConfig.cmake) for easier
integration with CMake projects.

The build logic now follows more idiomatic CMake practices with
configuration separated from target definitions.

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

6 files changed, 90 insertions, 0 deletions

diff --git a/cmake/config/ipcp/broadcast.cmake b/cmake/config/ipcp/broadcast.cmake
new file mode 100644
index 00000000..3c4d98da
--- /dev/null
+++ b/cmake/config/ipcp/broadcast.cmake
@@ -0,0 +1,4 @@
+# Broadcast IPCP configuration options for Ouroboros
+
+set(IPCP_BROADCAST_MPL 100 CACHE STRING
+  "Default maximum packet lifetime for the Broadcast IPCP, in ms")
diff --git a/cmake/config/ipcp/common.cmake b/cmake/config/ipcp/common.cmake
new file mode 100644
index 00000000..ffd5dc32
--- /dev/null
+++ b/cmake/config/ipcp/common.cmake
@@ -0,0 +1,43 @@
+# Common IPCP configuration options for Ouroboros
+# Options affecting all IPC Process types
+
+# Connection manager
+set(CONNMGR_RCV_TIMEOUT 1000 CACHE STRING
+  "Timeout for the connection manager to wait for OCEP info (ms).")
+
+# Debugging
+set(IPCP_DEBUG_LOCAL FALSE CACHE BOOL
+  "Use PID as address for local debugging")
+
+# QoS cube priorities (0-99, higher = more priority)
+set(IPCP_QOS_CUBE_BE_PRIO 50 CACHE STRING
+  "Priority for best effort QoS cube (0-99)")
+set(IPCP_QOS_CUBE_VIDEO_PRIO 90 CACHE STRING
+  "Priority for video QoS cube (0-99)")
+set(IPCP_QOS_CUBE_VOICE_PRIO 99 CACHE STRING
+  "Priority for voice QoS cube (0-99)")
+
+# Validate QoS cube priorities
+if((IPCP_QOS_CUBE_BE_PRIO LESS 0) OR (IPCP_QOS_CUBE_BE_PRIO GREATER 99))
+  message(FATAL_ERROR "Invalid priority for best effort QoS cube (must be 0-99)")
+endif()
+if((IPCP_QOS_CUBE_VIDEO_PRIO LESS 0) OR (IPCP_QOS_CUBE_VIDEO_PRIO GREATER 99))
+  message(FATAL_ERROR "Invalid priority for video QoS cube (must be 0-99)")
+endif()
+if((IPCP_QOS_CUBE_VOICE_PRIO LESS 0) OR (IPCP_QOS_CUBE_VOICE_PRIO GREATER 99))
+  message(FATAL_ERROR "Invalid priority for voice QoS cube (must be 0-99)")
+endif()
+
+# Threading
+set(IPCP_MIN_THREADS 4 CACHE STRING
+  "Minimum number of worker threads in the IPCP")
+set(IPCP_ADD_THREADS 4 CACHE STRING
+  "Number of extra threads to start when an IPCP faces thread starvation")
+set(IPCP_SCHED_THR_MUL 2 CACHE STRING
+  "Number of scheduler threads per QoS cube")
+
+# Linux-specific
+if(CMAKE_SYSTEM_NAME STREQUAL "Linux")
+  set(IPCP_LINUX_TIMERSLACK_NS 100 CACHE STRING
+      "Slack value for high resolution timers on Linux systems.")
+endif()
diff --git a/cmake/config/ipcp/eth.cmake b/cmake/config/ipcp/eth.cmake
new file mode 100644
index 00000000..2f50d24d
--- /dev/null
+++ b/cmake/config/ipcp/eth.cmake
@@ -0,0 +1,15 @@
+# Ethernet IPCP configuration options for Ouroboros
+# Options for eth-llc and eth-dix IPCPs
+
+set(IPCP_ETH_RD_THR 1 CACHE STRING
+  "Number of reader threads in Ethernet IPCP")
+set(IPCP_ETH_WR_THR 1 CACHE STRING
+  "Number of writer threads in Ethernet IPCP")
+set(IPCP_ETH_QDISC_BYPASS false CACHE BOOL
+  "Bypass the Qdisc in the kernel when using raw sockets")
+set(IPCP_ETH_LO_MTU 9000 CACHE STRING
+  "Restrict Ethernet MTU over loopback interfaces")
+set(IPCP_ETH_MGMT_FRAME_SIZE 9000 CACHE STRING
+  "Management frame buffer size for Ethernet IPCPs")
+set(IPCP_ETH_MPL 100 CACHE STRING
+  "Default maximum packet lifetime for the Ethernet IPCPs, in ms")
diff --git a/cmake/config/ipcp/local.cmake b/cmake/config/ipcp/local.cmake
new file mode 100644
index 00000000..df47c45b
--- /dev/null
+++ b/cmake/config/ipcp/local.cmake
@@ -0,0 +1,7 @@
+# Local IPCP configuration options for Ouroboros
+
+set(IPCP_LOCAL_MPL 100 CACHE STRING
+  "Default maximum packet lifetime for the Local IPCP, in ms")
+
+set(IPCP_LOCAL_POLLING FALSE CACHE BOOL
+  "Enable active polling in the Local IPCP for low-latency mode")
diff --git a/cmake/config/ipcp/udp.cmake b/cmake/config/ipcp/udp.cmake
new file mode 100644
index 00000000..691948ab
--- /dev/null
+++ b/cmake/config/ipcp/udp.cmake
@@ -0,0 +1,9 @@
+# UDP IPCP configuration options for Ouroboros
+# Options for udp4 and udp6 IPCPs
+
+set(IPCP_UDP_RD_THR 3 CACHE STRING
+  "Number of reader threads in UDP IPCPs")
+set(IPCP_UDP_WR_THR 3 CACHE STRING
+  "Number of writer threads in UDP IPCPs")
+set(IPCP_UDP_MPL 5000 CACHE STRING
+  "Default maximum packet lifetime for the UDP IPCPs, in ms")
diff --git a/cmake/config/ipcp/unicast.cmake b/cmake/config/ipcp/unicast.cmake
new file mode 100644
index 00000000..905c661a
--- /dev/null
+++ b/cmake/config/ipcp/unicast.cmake
@@ -0,0 +1,12 @@
+# Unicast IPCP configuration options for Ouroboros
+
+set(IPCP_UNICAST_MPL 100 CACHE STRING
+  "Default maximum packet lifetime for the Unicast IPCP, in ms")
+set(PFT_SIZE 256 CACHE STRING
+  "Prefix forwarding table size for the Unicast IPCP")
+
+# Protocol debugging
+set(DEBUG_PROTO_DHT FALSE CACHE BOOL
+  "Add DHT protocol debug logging")
+set(DEBUG_PROTO_LS FALSE CACHE BOOL
+  "Add link state protocol debug logging")