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diff --git a/readme.md b/readme.md new file mode 100644 index 0000000..4156e51 --- /dev/null +++ b/readme.md @@ -0,0 +1,132 @@ +# OPC UA Discovery + +A small C project that demonstrates OPC UA server discovery using the +[open62541](https://www.open62541.org/) library. Three programs work together: + +- **ServerLDS** — Local Discovery Server that other servers register with +- **ServerRegister** — a server that periodically registers itself with the LDS +- **Client** — queries the LDS for servers, lists endpoints, or reads the current time from a server + +## Prerequisites + +- CMake 4.0+ +- A C11 compiler (GCC or Clang) +- OpenSSL development libraries (`libssl-dev` / `openssl-devel`) +- `openssl` CLI (for generating certificates) + +## Getting started + +Clone the repository with its submodule: + +```sh +git clone --recursive https://git.tvcloud.fr/opcua_c +cd opcua_c +``` + +### Generate certificates + +The programs use TLS certificates for mutual authentication. Four identities +are needed — run these from the project root: + +```sh +tools/generate_certificate.sh certs ServerLDS +tools/generate_certificate.sh certs ServerRegister +tools/generate_certificate.sh certs ServerRegisterClient +tools/generate_certificate.sh certs ClientFindServers +``` + +### Populate the trust stores + +Each program trusts a specific set of peers. Copy the certificates into the +trust store directories so they can find each other: + +```sh +mkdir -p certs/trust/{server_lds,server_register,server_register_client,client} + +cp certs/ServerRegisterClient_cert.der certs/ClientFindServers_cert.der \ + certs/trust/server_lds/ + +cp certs/ServerLDS_cert.der certs/ClientFindServers_cert.der \ + certs/trust/server_register/ + +cp certs/ServerLDS_cert.der \ + certs/trust/server_register_client/ + +cp certs/ServerLDS_cert.der certs/ServerRegister_cert.der \ + certs/trust/client/ +``` + +### Build + +```sh +cmake -B build +cmake --build build --parallel +``` + +open62541 is fetched from the submodule and built automatically — the first +build takes a bit longer. + +## Running + +Start the programs in order, each in its own terminal, from the project root: + +```sh +# 1. Local Discovery Server +build/ServerLDS config/server_lds.conf + +# 2. Register Server (connects to the LDS on port 4840) +build/ServerRegister config/server_register.conf \ + config/server_register_client.conf opc.tcp://localhost:4840 + +# 3. Find registered servers via the LDS +build/Client config/client.conf find-servers opc.tcp://localhost:4840 + +# 4. List endpoints on the registered server +build/Client config/client.conf get-endpoints opc.tcp://localhost:4841 + +# 5. Read the current time from the registered server +build/Client config/client.conf read-time opc.tcp://localhost:4841 +``` + +All three programs accept an optional log level as the last argument +(`trace`, `debug`, `info`, `warning`, `error`, `fatal`). The default is `info`. + +## Tests + +Integration tests exercise four combinations of security and authentication: + +| Test | Security | Auth | +|------|----------|------| +| `none_anon` | None | anonymous | +| `none_user` | None | user/password | +| `basic256sha256_anon` | SignAndEncrypt / Basic256Sha256 | anonymous | +| `aes128_user` | SignAndEncrypt / Aes128_Sha256_RsaOaep | user/password | + +Run them: + +```sh +ctest --test-dir build --output-on-failure +``` + +### Memory leak check + +Rebuild with AddressSanitizer, run the tests, then switch back: + +```sh +# ASan build +cmake -B build \ + -DCMAKE_C_FLAGS="-fsanitize=address -fno-omit-frame-pointer" \ + -DCMAKE_EXE_LINKER_FLAGS="-fsanitize=address" +cmake --build build --parallel + +ASAN_OPTIONS="detect_leaks=1" ctest --test-dir build --output-on-failure + +# Restore normal build +cmake -B build -DCMAKE_C_FLAGS="" -DCMAKE_EXE_LINKER_FLAGS="" +cmake --build build --parallel +``` + +## Configuration + +Programs are configured through plain text files (`key = value`, one per line). +Example configs are in `config/`. |