Sstrhsrtj

When I am connected to a network, I can send a struct rt_msghdr* to the kernel and receive a corresponding route. However, when I disconnect from the network and try to send the same route message header, the socket fails at send() with errno = ESRCH (3) No such process.

Generic code: (Testing on MacOS)

int sd = create_socket(AF_ROUTE, IPPROTO_RAW, AF_UNSPEC);



memset(&buffer[0], 0, buffer.size());

struct rt_msghdr* rmh = (struct rt_msghdr*)(&buffer[0]);

rmh->rtm_msglen       = sizeof(struct rt_msghdr) + sizeof(struct sockaddr_in);

rmh->rtm_version      = RTM_VERSION;

rmh->rtm_type         = RTM_GET;

rmh->rtm_addrs        = RTA_DST;

rmh->rtm_pid          = getpid();

rmh->rtm_seq          = 1;

struct sockaddr_in* sa_in = (struct sockaddr_in*)(rmh + 1);

sa_in->sin_len            = sizeof(struct sockaddr_in);

sa_in->sin_family         = AF_INET;



int status;

if ((status = send(sd, rmh, rmh->rtm_msglen, 0) < 0) {

    // process errno

    // * issue happens here when not connected to a network

}



// receive kernel response(s)

// process responses



close(sd);

I verified that the process ID (pid) is being set correctly in the header. netstat -nr returns the default route without issue when not connected to a network. I'm having trouble understanding why this code is dependent on network connectivity.