Expose async_get_source_ip in the network integration (#52901)

* Expose async_get_source_ip in the network integration

* Handle source ip on disabled interface

* add coverage

homeassistant/components/network/__init__.py

@@ -11,6 +11,7 @@ from homeassistant.core import HomeAssistant
 from homeassistant.helpers.typing import ConfigType
 from homeassistant.loader import bind_hass
 
+from . import util
 from .const import (
     ATTR_ADAPTERS,
     ATTR_CONFIGURED_ADAPTERS,
@@ -31,6 +32,19 @@ async def async_get_adapters(hass: HomeAssistant) -> list[Adapter]:
     return network.adapters
 
 
+@bind_hass
+async def async_get_source_ip(hass: HomeAssistant, target_ip: str) -> str | None:
+    """Get the source ip for a target ip."""
+    adapters = await async_get_adapters(hass)
+    all_ipv4s = []
+    for adapter in adapters:
+        if adapter["enabled"] and (ipv4s := adapter["ipv4"]):
+            all_ipv4s.extend([ipv4["address"] for ipv4 in ipv4s])
+
+    source_ip = util.async_get_source_ip(target_ip)
+    return source_ip if source_ip in all_ipv4s else all_ipv4s[0]
+
+
 async def async_setup(hass: HomeAssistant, config: ConfigType) -> bool:
     """Set up network for Home Assistant."""
 

tests/components/network/test_init.py

@@ -7,6 +7,7 @@ from homeassistant.components import network
 from homeassistant.components.network.const import (
     ATTR_ADAPTERS,
     ATTR_CONFIGURED_ADAPTERS,
+    MDNS_TARGET_IP,
     STORAGE_KEY,
     STORAGE_VERSION,
 )
@@ -444,3 +445,66 @@ async def test_interfaces_configured_from_storage_websocket_update(
             "name": "vtun0",
         },
     ]
+
+
+async def test_async_get_source_ip_matching_interface(hass, hass_storage):
+    """Test getting the source ip address with interface matching."""
+    hass_storage[STORAGE_KEY] = {
+        "version": STORAGE_VERSION,
+        "key": STORAGE_KEY,
+        "data": {ATTR_CONFIGURED_ADAPTERS: ["eth1"]},
+    }
+
+    with patch(
+        "homeassistant.components.network.util.ifaddr.get_adapters",
+        return_value=_generate_mock_adapters(),
+    ), patch(
+        "homeassistant.components.network.util.socket.socket.getsockname",
+        return_value=["192.168.1.5"],
+    ):
+        assert await async_setup_component(hass, network.DOMAIN, {network.DOMAIN: {}})
+        await hass.async_block_till_done()
+
+        assert await network.async_get_source_ip(hass, MDNS_TARGET_IP) == "192.168.1.5"
+
+
+async def test_async_get_source_ip_interface_not_match(hass, hass_storage):
+    """Test getting the source ip address with interface does not match."""
+    hass_storage[STORAGE_KEY] = {
+        "version": STORAGE_VERSION,
+        "key": STORAGE_KEY,
+        "data": {ATTR_CONFIGURED_ADAPTERS: ["vtun0"]},
+    }
+
+    with patch(
+        "homeassistant.components.network.util.ifaddr.get_adapters",
+        return_value=_generate_mock_adapters(),
+    ), patch(
+        "homeassistant.components.network.util.socket.socket.getsockname",
+        return_value=["192.168.1.5"],
+    ):
+        assert await async_setup_component(hass, network.DOMAIN, {network.DOMAIN: {}})
+        await hass.async_block_till_done()
+
+        assert await network.async_get_source_ip(hass, MDNS_TARGET_IP) == "169.254.3.2"
+
+
+async def test_async_get_source_ip_cannot_determine_target(hass, hass_storage):
+    """Test getting the source ip address when getsockname fails."""
+    hass_storage[STORAGE_KEY] = {
+        "version": STORAGE_VERSION,
+        "key": STORAGE_KEY,
+        "data": {ATTR_CONFIGURED_ADAPTERS: ["eth1"]},
+    }
+
+    with patch(
+        "homeassistant.components.network.util.ifaddr.get_adapters",
+        return_value=_generate_mock_adapters(),
+    ), patch(
+        "homeassistant.components.network.util.socket.socket.getsockname",
+        return_value=[None],
+    ):
+        assert await async_setup_component(hass, network.DOMAIN, {network.DOMAIN: {}})
+        await hass.async_block_till_done()
+
+        assert await network.async_get_source_ip(hass, MDNS_TARGET_IP) == "192.168.1.5"