Initial commit: wireframe packet capture/analysis tool

Terminal packet capture and analysis tool built to learn the C++
memory model (byte layout, alignment, endianness, std::span over
unowned buffers) via a real capture pipeline.

- Hand-rolled L2-L4 decoders (Ethernet, IPv4, IPv6 with extension
  header walking, TCP, UDP) over std::span, no struct-casting
- L7 dissector interface with DNS, HTTP, and TLS SNI implementations
- pcapng read/write for Wireshark-compatible capture files
- Bounded capture queue: drop-on-backpressure for live capture,
  blocking push for faithful file replay
- Kernel-level BPF filtering (-f) and a separate display-only search
  (-g / interactive) that doesn't touch what's captured
- Replay mode (-r) reads a saved pcapng file back through the same
  pipeline as live capture, no root or live device needed
- pcap_stats() surfaces kernel/interface drops invisible to the
  capture queue's own counter
- Three frontends sharing one CaptureSession setup path: CLI, TUI
  (FTXUI, primary), GUI (Dear ImGui + SDL3, secondary)
- 89 unit tests (doctest) plus 9 libFuzzer harnesses covering every
  hand-rolled parser; fuzzing found and fixed a real OOM in the
  pcapng reader (unbounded allocation from an untrusted length field)

1 files changed, 136 insertions, 0 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
new file mode 100644
index 0000000..211738a
--- /dev/null
+++ b/CMakeLists.txt
@@ -0,0 +1,136 @@
+cmake_minimum_required(VERSION 3.20)
+project(wireframe CXX)
+
+set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
+if(NOT CMAKE_BUILD_TYPE)
+  set(CMAKE_BUILD_TYPE Debug)
+endif()
+
+add_compile_options(-Wall -Wextra)
+
+find_package(Threads REQUIRED)
+
+include(FetchContent)
+FetchContent_Declare(
+  ftxui
+  GIT_REPOSITORY https://github.com/ArthurSonzogni/FTXUI.git
+  GIT_TAG v7.0.3
+  GIT_SHALLOW TRUE
+)
+FetchContent_MakeAvailable(ftxui)
+
+add_executable(wireframe src/main.cpp)
+target_include_directories(wireframe PRIVATE include)
+target_link_libraries(wireframe PRIVATE
+  pcap
+  Threads::Threads
+  ftxui::component
+  ftxui::dom
+  ftxui::screen
+)
+
+# GUI (secondary to the TUI - see PLAN.md Decisions). Dear ImGui +
+# SDL3, same FetchContent approach as FTXUI/doctest: no dependency on
+# a system package, so it builds the same way on every platform this
+# project targets. SDL3 over SDL2 because sdl2-compat (an SDL3-backed
+# shim) is what's actually packaged in this ecosystem now - SDL3 is
+# the live line. SDL_Renderer (not raw OpenGL3) avoids needing a
+# separate GL function loader as another dependency.
+set(SDL_SHARED OFF CACHE BOOL "" FORCE)
+set(SDL_STATIC ON CACHE BOOL "" FORCE)
+set(SDL_TEST_LIBRARY OFF CACHE BOOL "" FORCE)
+FetchContent_Declare(
+  sdl3
+  GIT_REPOSITORY https://github.com/libsdl-org/SDL.git
+  GIT_TAG release-3.4.14
+  GIT_SHALLOW TRUE
+)
+FetchContent_MakeAvailable(sdl3)
+
+FetchContent_Declare(
+  imgui
+  GIT_REPOSITORY https://github.com/ocornut/imgui.git
+  GIT_TAG v1.92.9b
+  GIT_SHALLOW TRUE
+)
+FetchContent_MakeAvailable(imgui)
+
+add_library(imgui STATIC
+  ${imgui_SOURCE_DIR}/imgui.cpp
+  ${imgui_SOURCE_DIR}/imgui_draw.cpp
+  ${imgui_SOURCE_DIR}/imgui_tables.cpp
+  ${imgui_SOURCE_DIR}/imgui_widgets.cpp
+  ${imgui_SOURCE_DIR}/backends/imgui_impl_sdl3.cpp
+  ${imgui_SOURCE_DIR}/backends/imgui_impl_sdlrenderer3.cpp
+)
+target_include_directories(imgui PUBLIC ${imgui_SOURCE_DIR} ${imgui_SOURCE_DIR}/backends)
+target_link_libraries(imgui PUBLIC SDL3::SDL3)
+
+add_executable(wireframe_gui src/gui_main.cpp)
+target_include_directories(wireframe_gui PRIVATE include)
+target_link_libraries(wireframe_gui PRIVATE pcap Threads::Threads imgui SDL3::SDL3)
+
+enable_testing()
+
+FetchContent_Declare(
+  doctest
+  GIT_REPOSITORY https://github.com/doctest/doctest.git
+  GIT_TAG v2.5.3
+  GIT_SHALLOW TRUE
+)
+FetchContent_MakeAvailable(doctest)
+
+add_executable(wireframe_tests
+  tests/main.cpp
+  tests/test_byteio.cpp
+  tests/test_net.cpp
+  tests/test_ipv6.cpp
+  tests/test_dns.cpp
+  tests/test_http.cpp
+  tests/test_tls.cpp
+  tests/test_pcapng.cpp
+  tests/test_capture_queue.cpp
+  tests/test_filter.cpp
+  tests/test_summarize.cpp
+  tests/test_capture_session.cpp
+  tests/test_search.cpp
+)
+target_include_directories(wireframe_tests PRIVATE include)
+target_link_libraries(wireframe_tests PRIVATE doctest::doctest Threads::Threads pcap)
+
+add_test(NAME wireframe_tests COMMAND wireframe_tests)
+
+# libFuzzer harnesses for the hand-rolled decoders - the actual point
+# of this project (byte layout/alignment/UB) makes these the highest-
+# value tests in the repo, not an afterthought. Opt-in and clang-only
+# (libFuzzer is a clang/compiler-rt feature) so a normal `cmake --build`
+# with the default compiler is unaffected.
+option(WIREFRAME_ENABLE_FUZZING "Build libFuzzer harnesses (requires clang)" OFF)
+if(WIREFRAME_ENABLE_FUZZING)
+  if(NOT CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
+    message(FATAL_ERROR "WIREFRAME_ENABLE_FUZZING requires clang (libFuzzer); "
+                         "reconfigure with -DCMAKE_CXX_COMPILER=clang++")
+  endif()
+
+  function(add_wireframe_fuzz_target name)
+    add_executable(${name} fuzz/${name}.cpp)
+    target_include_directories(${name} PRIVATE include)
+    target_link_libraries(${name} PRIVATE pcap)
+    target_compile_options(${name} PRIVATE -fsanitize=fuzzer,address,undefined -g -O1)
+    target_link_options(${name} PRIVATE -fsanitize=fuzzer,address,undefined)
+  endfunction()
+
+  add_wireframe_fuzz_target(fuzz_ethernet)
+  add_wireframe_fuzz_target(fuzz_ipv4)
+  add_wireframe_fuzz_target(fuzz_ipv6)
+  add_wireframe_fuzz_target(fuzz_tcp)
+  add_wireframe_fuzz_target(fuzz_udp)
+  add_wireframe_fuzz_target(fuzz_dns)
+  add_wireframe_fuzz_target(fuzz_http)
+  add_wireframe_fuzz_target(fuzz_tls)
+  add_wireframe_fuzz_target(fuzz_pcapng_reader)
+  add_wireframe_fuzz_target(fuzz_summarize)
+endif()