Android10 rk3399 以太网接入流程分析

Netd守护进程服务

• Netd模块是Android中专门负责网络管理和控制的后台守护进程
• 开发板路径./etc/init/netd.rc

service netd /system/bin/netd
    class main
    socket dnsproxyd stream 0660 root inet
    socket mdns stream 0660 root system
    socket fwmarkd stream 0660 root inet
    onrestart restart zygote
    onrestart restart zygote_secondary
    # b/121354779: netd itself is not updatable, but on startup it dlopen()s the resolver library
    # from the DNS resolver APEX. Mark it as updatable so init won't start it until all APEX
    # packages are ready.
    updatable
~

Netd源码分析

system\netd\server\main.cpp

int main() {
    Stopwatch s;
    gLog.info("netd 1.0 starting");

    android::net::process::removePidFile(PID_FILE_PATH);
    android::net::process::blockSigPipe();

    // Before we do anything that could fork, mark CLOEXEC the UNIX sockets that we get from init.
    // FrameworkListener does this on initialization as well, but we only initialize these
    // components after having initialized other subsystems that can fork.
    for (const auto& sock :
         {DNSPROXYLISTENER_SOCKET_NAME, FwmarkServer::SOCKET_NAME, MDnsSdListener::SOCKET_NAME}) {
        setCloseOnExec(sock);
    }

    // Before we start any threads, populate the resolver stub pointers.
    resolv_stub_init();

    // Make sure BPF programs are loaded before doing anything
    while (!android::base::WaitForProperty("bpf.progs_loaded", "