how do you cast sockaddr structure to a sockaddr_in - C++ networking sockets ubuntu UDP
c++, client, networking, sockets, ubuntu
Solution
I would point out that if this is actually C++ the idiomatic way to do this would be:
sockaddr *sa = ...; // struct not needed in C++
char ip[INET6_ADDRSTRLEN] = {0};
switch (sa->sa_family) {
case AF_INET: {
// use of reinterpret_cast preferred to C style cast
sockaddr_in *sin = reinterpret_cast<sockaddr_in*>(sa);
inet_ntop(AF_INET, &sin->sin_addr, ip, INET6_ADDRSTRLEN);
break;
}
case AF_INET6: {
sockaddr_in6 *sin = reinterpret_cast<sockaddr_in6*>(sa);
// inet_ntoa should be considered deprecated
inet_ntop(AF_INET6, &sin->sin6_addr, ip, INET6_ADDRSTRLEN);
break;
}
default:
abort();
}
This sample code handles IPv4 and IPv6 addresses and also would be considered more C++ idiomatic than either of the suggested implementations.
Problem
I am trying to get the client address, but i am unsure how do i cast the sockaddr structure to sockaddr_in? ``` struct sockaddr_in cliAddr, servAddr; n = recvfrom(sd, msg, MAX_MSG, 0,(struct sockaddr *) cliAddr,sizeof(cliAddr)); //i tried this but it does not work struct sockaddr cliSockAddr = (struct sockaddr *) cliAddr; char *ip = inet_ntoa(cliSockAddr.sin_addr); ``` Thanks in advance! :) i've found questions that brought me to this step: Getting IPV4 address from a sockaddr structure Sorry to avoid confusion, this is my real implementation where "ci" is an object to store pointers such as sockaddr_in. ``` /* receive message */ n = recvfrom(*(ci->getSd()), msg, MAX_MSG, 0,(struct sockaddr *) ci->getCliAddr(),ci->getCliLen()); char *ip = inet_ntoa(ci->getCliAddr().sin_addr); ``` i will get the following errors: ``` udpserv.cpp:166: error: request for member ‘sin_addr’ in ‘ci->clientInfo::getCliAddr()’, which is of non-class type ‘sockaddr_in*’ ```