feat(avahi): Initial avahi port

Note the LGPL license, add a warning!

.gitmodules

@@ -4,3 +4,6 @@
 [submodule "components/mosquitto/mosquitto"]
 	path = components/mosquitto/mosquitto
 	url = https://github.com/eclipse/mosquitto
+[submodule "components/avahi/avahi"]
+	path = components/avahi/avahi
+	url = https://github.com/avahi/avahi.git

.pre-commit-config.yaml

@@ -61,8 +61,8 @@ repos:
   - repo: local
     hooks:
       - id: commit message scopes
-        name: "commit message must be scoped with: mdns, modem, websocket, asio, mqtt_cxx, console, common, eppp, tls_cxx, mosq, sockutls"
-        entry: '\A(?!(feat|fix|ci|bump|test|docs|chore)\((mdns|modem|common|console|websocket|asio|mqtt_cxx|examples|eppp|tls_cxx|mosq|sockutls)\)\:)'
+        name: "commit message must be scoped with: mdns, modem, websocket, asio, mqtt_cxx, console, common, eppp, tls_cxx, mosq, sockutls, avahi"
+        entry: '\A(?!(feat|fix|ci|bump|test|docs|chore)\((mdns|modem|common|console|websocket|asio|mqtt_cxx|examples|eppp|tls_cxx|mosq|sockutls|avahi)\)\:)'
         language: pygrep
         args: [--multiline]
         stages: [commit-msg]

ci/check_copyright_config.yaml

@@ -55,6 +55,14 @@ mosquitto_component:
     - Apache-2.0
     - BSD-3-Clause
 
+avahi_component:
+  include:
+    - 'components/avahi/**'
+  allowed_licenses:
+    - LGPL-2.1
+    - Apache-2.0
+    - Unlicense OR CC0-1.0
+
 slim_modem_examples:
   include:
     - 'examples/esp_netif/slip_custom_netif/**'

components/avahi/CMakeLists.txt

@@ -0,0 +1,60 @@
+set(avahi_path "avahi")
+set(avahi_core "${avahi_path}/avahi-core")
+set(avahi_common "${avahi_path}/avahi-common")
+set(avahi_core_SRCS "${avahi_core}/server.c"
+        "${avahi_common}/error.c"
+        "${avahi_common}/malloc.c"
+        "${avahi_common}/simple-watch.c"
+        "${avahi_common}/domain.c"
+        "${avahi_common}/timeval.c"
+        "${avahi_common}/strlst.c"
+        "${avahi_common}/address.c"
+        "${avahi_common}/rlist.c"
+        "${avahi_common}/utf8.c"
+        "${avahi_core}/log.c"
+        "${avahi_core}/rr.c"
+        "${avahi_core}/response-sched.c"
+        "${avahi_core}/probe-sched.c"
+        "${avahi_core}/query-sched.c"
+        "${avahi_core}/rrlist.c"
+        "${avahi_core}/hashmap.c"
+        "${avahi_core}/announce.c"
+        "${avahi_core}/domain-util.c"
+        "${avahi_core}/multicast-lookup.c"
+        "${avahi_core}/iface.c"
+        "${avahi_core}/entry.c"
+        "${avahi_core}/cache.c"
+        "${avahi_core}/util.c"
+        "${avahi_core}/addr-util.c"
+        "${avahi_core}/timeeventq.c"
+        "${avahi_core}/querier.c"
+        "${avahi_core}/browse.c"
+        "${avahi_core}/dns.c"
+        "${avahi_core}/wide-area.c"
+        "${avahi_core}/prioq.c"
+        "${avahi_core}/fdutil.c"
+        "${avahi_core}/browse-domain.c"
+        "${avahi_core}/browse-dns-server.c"
+        "${avahi_core}/browse-service.c"
+        "${avahi_core}/resolve-host-name.c"
+        "${avahi_core}/resolve-address.c"
+        "${avahi_core}/resolve-service.c"
+        "${avahi_core}/browse-service-type.c"
+        # "${avahi_core}/browse-record.c"
+        # "${avahi_core}/resolve-service-group.c"
+        # "${avahi_core}/resolve-record.c"
+)
+
+idf_component_register(SRCS "avahi-port/iface-esp32.c"
+                            "avahi-port/socket.c"
+                            ${avahi_core_SRCS}
+                    INCLUDE_DIRS "avahi-port" "${avahi_core}" "${avahi_path}"
+                    REQUIRES "esp_netif")
+
+target_compile_definitions(${COMPONENT_LIB} PRIVATE "HAVE_CONFIG_H")
+# ignore specific warnings on certain files
+set_source_files_properties(${avahi_common}/domain.c PROPERTIES COMPILE_FLAGS -Wno-char-subscripts)
+set_source_files_properties(${avahi_core}/rr.c PROPERTIES COMPILE_FLAGS -Wno-format)
+set_source_files_properties(${avahi_core}/iface.c PROPERTIES COMPILE_FLAGS -Wno-format)
+set_source_files_properties(${avahi_core}/entry.c PROPERTIES COMPILE_FLAGS -Wno-format)
+set_source_files_properties(${avahi_common}/address.c PROPERTIES COMPILE_FLAGS -Wno-format)

components/avahi/README.md

@@ -0,0 +1,8 @@
+# Simple ESP-IDF avahi port
+
+This is a simple port of avahi for ESP-IDF. It is based on the avahi-core library and is intended to be used as a mDNS service browser.
+
+## Warning
+
+This component uses avahi project which is distributed under the LGPL license. This means that you have to provide the source code of your project to the end user if you use this component in your project.
+For more details, please refer to the [LICENSE](LICENSE.txt) file.