#include #include #include #include #include #include #include #define DEBUG 0 static int _tcp_socket(int protocol); static int _udp_socket(int protocol); int socket(int domain, int type, int protocol) { #if DEBUG fprintf(stderr, "socket: domain %d, type %d, protocol %d\n", domain, type, protocol); #endif if (domain != AF_INET) { #if DEBUG fprintf(stderr, "socket: bad domain %d\n", domain); #endif errno= EAFNOSUPPORT; return -1; } if (type == SOCK_STREAM) return _tcp_socket(protocol); if (type == SOCK_DGRAM) return _udp_socket(protocol); #if DEBUG fprintf(stderr, "socket: nothing for domain %d, type %d, protocol %d\n", domain, type, protocol); #endif errno= EPROTOTYPE; return -1; } static int _tcp_socket(int protocol) { int fd; if (protocol != 0 && protocol != IPPROTO_TCP) { #if DEBUG fprintf(stderr, "socket(tcp): bad protocol %d\n", protocol); #endif errno= EPROTONOSUPPORT; return -1; } fd= open(TCP_DEVICE, O_RDWR); return fd; } static int _udp_socket(int protocol) { int fd; if (protocol != 0 && protocol != IPPROTO_UDP) { #if DEBUG fprintf(stderr, "socket(udp): bad protocol %d\n", protocol); #endif errno= EPROTONOSUPPORT; return -1; } fd= open(UDP_DEVICE, O_RDWR); return fd; }