基于mac的服务端客户端通信程序

/* passivesock.c - passivesock */ #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <stdlib.h> #include <string.h> #include <netdb.h> extern int errno; int errexit(const char *format, ...); unsigned short portbase = 0; /* port base, for non-root servers */ /*------------------------------------------------------------------------ * passivesock - allocate & bind a server socket using TCP or UDP *------------------------------------------------------------------------ */ int passivesock(const char *service, const char *transport, int qlen) /* * Arguments: * service - service associated with the desired port * transport - transport protocol to use ("tcp" or "udp") * qlen - maximum server request queue length */ { struct servent *pse; /* pointer to service information entry */ struct protoent *ppe; /* pointer to protocol information entry*/ struct sockaddr_in sin; /* an Internet endpoint address */ int s, type; /* socket descriptor and socket type */ memset(&sin, 0, sizeof(sin)); sin.sin_family = AF_INET; sin.sin_addr.s_addr = INADDR_ANY; /* Map service name to port number */ if ( pse = getservbyname(service, transport) ) sin.sin_port = htons(ntohs((unsigned short)pse->s_port) + portbase); else if ((sin.sin_port=htons((unsigned short)atoi(service))) == 0) errexit("can't get \"%s\" service entry\n", service); /* Map protocol name to protocol number */ if ( (ppe = getprotobyname(transport)) == 0) errexit("can't get \"%s\" protocol entry\n", transport); /* Use protocol to choose a socket type */ if (strcmp(transport, "udp") == 0) type = SOCK_DGRAM; else type = SOCK_STREAM; /* Allocate a socket */ s = socket(PF_INET, type, ppe->p_proto); if (s < 0) errexit("can't create socket: %s\n", strerror(errno)); /* Bind the socket */ if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) < 0) errexit("can't bind to %s port: %s\n", service, strerror(errno)); if (type == SOCK_STREAM && listen(s, qlen) < 0) errexit("can't listen on %s port: %s\n", service, strerror(errno)); return s; }