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[Linux] Prioritize interface matching for WiFi MAC address (#23813)
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Prefer interface matching the WiFi interface name when
obtaining WiFi MAC address. Fallback to use first
non-loopback interface if no match is found.
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zqiu-nest authored Nov 30, 2022
1 parent 23aafa6 commit 4a8f8eb
Showing 1 changed file with 23 additions and 8 deletions.
31 changes: 23 additions & 8 deletions src/platform/Linux/ConfigurationManagerImpl.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -129,31 +129,46 @@ CHIP_ERROR ConfigurationManagerImpl::Init()
CHIP_ERROR ConfigurationManagerImpl::GetPrimaryWiFiMACAddress(uint8_t * buf)
{
struct ifaddrs * addresses = nullptr;
struct sockaddr_ll * mac = nullptr;
CHIP_ERROR error = CHIP_NO_ERROR;
bool found = false;

// TODO: ideally the buffer size should have been passed as a span, however
// for now use the size that is validated in GenericConfigurationManagerImpl.ipp
constexpr size_t kExpectedBufMinSize = ConfigurationManager::kPrimaryMACAddressLength;
memset(buf, 0, kExpectedBufMinSize);

// Prioritize address for interface matching the WiFi interface name
// specified in the config headers. Otherwise, use the address for the
// first non-loopback interface.
VerifyOrExit(getifaddrs(&addresses) == 0, error = CHIP_ERROR_INTERNAL);
for (auto addr = addresses; addr != nullptr; addr = addr->ifa_next)
{
if ((addr->ifa_addr) && (addr->ifa_addr->sa_family == AF_PACKET) && strncmp(addr->ifa_name, "lo", IFNAMSIZ) != 0)
if ((addr->ifa_addr) && (addr->ifa_addr->sa_family == AF_PACKET))
{
struct sockaddr_ll * mac = (struct sockaddr_ll *) addr->ifa_addr;
memcpy(buf, mac->sll_addr, std::min<size_t>(mac->sll_halen, kExpectedBufMinSize));
found = true;
break;
if (strncmp(addr->ifa_name, CHIP_DEVICE_CONFIG_WIFI_STATION_IF_NAME, IFNAMSIZ) == 0)
{
mac = (struct sockaddr_ll *) addr->ifa_addr;
break;
}

if (strncmp(addr->ifa_name, "lo", IFNAMSIZ) != 0 && !mac)
{
mac = (struct sockaddr_ll *) addr->ifa_addr;
}
}
}
freeifaddrs(addresses);
if (!found)

if (mac)
{
memcpy(buf, mac->sll_addr, std::min<size_t>(mac->sll_halen, kExpectedBufMinSize));
}
else
{
error = CHIP_ERROR_NO_ENDPOINT;
}

freeifaddrs(addresses);

exit:
return error;
}
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