/*
*
* Function: main()
*
*/
int
main(int argc, char *argv[])
{
char *program_name = argv[0];
int optc; /* option */
int sock_fd; /* socket descriptor for a connection */
char *server_name; /* Name (or IP address) of the server */
sa_family_t family; /* protocol family */
char *portnum; /* port number in string representation */
struct addrinfo hints; /* hints for getaddrinfo() */
struct addrinfo *res; /* pointer to addrinfo structure */
int err; /* return value of getaddrinfo */
int on; /* on/off at an socket option */
int recvbuf_size; /* size of the receive buffer */
int sock_optlen; /* size of the result parameter */
char *recvbuf; /* pointer to the received message */
ssize_t recvbyte_size; /* size of the receive byte */
time_t start_time; /* time when the timer is start */
double timeout = 0.0; /* timeout */
int background = 0; /* If non-zero work in the background */
size_t window_scaling = 0; /* if non-zero, in the window scaling mode */
debug = 0;
/* Initilalize the client information */
family = PF_UNSPEC;
server_name = NULL;
portnum = NULL;
/* Retrieve the options */
while ((optc = getopt(argc, argv, "S:f:p:t:bwdh")) != EOF) {
switch (optc) {
case 'S':
server_name = strdup(optarg);
if (server_name == NULL) {
fprintf(stderr, "strdup() failed.");
exit(EXIT_FAILURE);
}
break;
case 'f':
if (strncmp(optarg, "4", 1) == 0)
family = PF_INET; /* IPv4 */
else if (strncmp(optarg, "6", 1) == 0)
family = PF_INET6; /* IPv6 */
else {
fprintf(stderr, "protocol family should be 4 or 6.\n");
usage(program_name, EXIT_FAILURE);
}
break;
case 'p':
{
unsigned long int tmp;
tmp = strtoul(optarg, NULL, 0);
if (tmp < PORTNUMMIN || PORTNUMMAX < tmp) {
fprintf(stderr, "The range of port is from %u to %u\n",
PORTNUMMIN, PORTNUMMAX);
usage(program_name, EXIT_FAILURE);
}
portnum = strdup(optarg);
}
break;
case 't':
timeout = strtod(optarg, NULL);
if (timeout < 0) {
fprintf(stderr, "Timeout value is bigger than 0\n");
usage(program_name, EXIT_FAILURE);
}
break;
case 'b':
background = 1;
break;
case 'w':
window_scaling = 1;
break;
case 'd':
debug = 1;
break;
case 'h':
usage(program_name, EXIT_SUCCESS);
break;
default:
usage(program_name, EXIT_FAILURE);
}
}
/* Check the server name is specified. */
if (server_name == NULL) {
fprintf(stderr, "server name isn't specified.\n");
usage(program_name, EXIT_FAILURE);
}
/* Check the family is specified. */
if (family == PF_UNSPEC) {
fprintf(stderr, "protocol family isn't specified.\n");
usage(program_name, EXIT_FAILURE);
}
/* Check the port number is specified. */
if (portnum == NULL) {
fprintf(stderr, "port number isn't specified.\n");
usage(program_name, EXIT_FAILURE);
}
/* At first, SIGHUP are Ignored. */
handler.sa_handler = set_signal_flag;
handler.sa_flags = 0;
if (sigfillset(&handler.sa_mask) < 0)
fatal_error("sigfillset()");
if (sigaction(SIGHUP, &handler, NULL) < 0)
fatal_error("sigaction()");
/* Set the hints to addrinfo() */
memset(&hints, '\0', sizeof(struct addrinfo));
hints.ai_family = family;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;
/* Translate the network and service information of the client */
err = getaddrinfo(server_name, portnum, &hints, &res);
if (err) {
fprintf(stderr, "getaddrinfo(): %s\n", gai_strerror(err));
exit(EXIT_FAILURE);
}
if (res->ai_next) {
fprintf(stderr, "getaddrinfo(): multiple address is found.");
exit(EXIT_FAILURE);
}
/* Create a socket */
sock_fd = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
if (sock_fd < 0)
fatal_error("socket()");
/* Enable to reuse the socket */
on = 1;
if (setsockopt(sock_fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(int)))
fatal_error("setsockopt()");
/* Maximize socket buffer, when window scaling mode */
if (window_scaling)
maximize_sockbuf(sock_fd);
/* Connect to the server */
if (connect(sock_fd, res->ai_addr, res->ai_addrlen) < 0)
fatal_error("connect()");
freeaddrinfo(res);
free(server_name);
/* If -b option is specified, work as a daemon */
if (background)
if (daemon(0, 0) < 0)
fatal_error("daemon()");
/* Get the size of receive buffer */
sock_optlen = sizeof(recvbuf_size);
if (getsockopt(sock_fd, SOL_SOCKET, SO_RCVBUF, &recvbuf_size, &sock_optlen) < 0)
fatal_error("getsockopt()");
if (debug)
fprintf(stderr, "recvbuf size of socket(%d) is %d\n", sock_fd, recvbuf_size);
/* Prepare a buffer to receive bytes */
recvbuf = (char *)malloc(recvbuf_size);
if (recvbuf == NULL) {
fprintf(stderr, "malloc() is failed.\n");
exit(EXIT_FAILURE);
}
/*
* Loop for receiving data from the server
*/
start_time = time(NULL);
handler.sa_handler = set_signal_flag;
if (sigaction(SIGHUP, &handler, NULL) < 0)
fatal_error("sigaction()");
for(;;) {
recvbyte_size = recv(sock_fd, recvbuf, recvbuf_size, 0);
if (recvbyte_size < (ssize_t)0) {
if (catch_sighup)
break;
else
fatal_error("sendto()");
}
else if (recvbyte_size == (ssize_t)0)
break;
/* client timeout */
if (timeout)
if (timeout < difftime(time(NULL), start_time))
break;
/* Catch SIGHUP */
if (catch_sighup)
break;
}
if (close(sock_fd) < 0)
fatal_error("close()");
free(recvbuf);
if (debug)
fprintf (stderr, "Client is finished without any error\n");
exit(EXIT_SUCCESS);
}
/*
* Function: create_listen_socket()
*
* Descripton:
* Create a socket to listen for connections on a socket.
* The socket discripter is stored info_p->listen_sd.
*
* Argument:
* info_p: pointer to a server infomation
*
* Return value:
* None
*/
void
create_listen_socket(struct server_info *info_p)
{
int on; /* on/off at an socket option */
int err; /* return value of getaddrinfo */
struct addrinfo hints; /* hints for getaddrinfo() */
struct addrinfo *res; /* pointer to addrinfo */
/* Set the hints to addrinfo() */
memset(&hints, '\0', sizeof(struct addrinfo));
hints.ai_family = info_p->family;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;
hints.ai_flags = AI_PASSIVE;
/* Translate the network and service information of the server */
err = getaddrinfo(NULL, info_p->portnum, &hints, &res);
if (err) {
fprintf(stderr, "getaddrinfo(): %s\n", gai_strerror(err));
exit(EXIT_FAILURE);
}
if (res->ai_next) {
fprintf(stderr, "getaddrinfo(): multiple address is found.");
exit(EXIT_FAILURE);
}
/* Create a socket for listening. */
info_p->listen_sd = socket(res->ai_family,
res->ai_socktype, res->ai_protocol);
if (info_p->listen_sd < 0)
fatal_error("socket()");
#ifdef IPV6_V6ONLY
/* Don't accept IPv4 mapped address if the protocol family is IPv6 */
if (res->ai_family == PF_INET6) {
on = 1;
if (setsockopt(info_p->listen_sd,
IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(int)))
fatal_error("setsockopt()");
}
#endif
/* Enable to reuse the socket */
on = 1;
if (setsockopt(info_p->listen_sd,
SOL_SOCKET, SO_REUSEADDR, &on, sizeof(int)))
fatal_error("setsockopt()");
/* Disable the Nagle algorithm, when small sending mode */
if (info_p->small_sending) {
on = 1;
if (setsockopt(info_p->listen_sd,
IPPROTO_TCP, TCP_NODELAY, &on, sizeof(int)))
fatal_error("setsockopt()");
if (debug) {
fprintf(stderr, "small sending[on]\n");
}
}
/* Maximize socket buffer, when window scaling mode */
if (info_p->window_scaling)
maximize_sockbuf(info_p->listen_sd);
/* Bind to the local address */
if (bind(info_p->listen_sd, res->ai_addr, res->ai_addrlen) < 0)
fatal_error("bind()");
freeaddrinfo(res);
/* Start to listen for connections */
if (listen(info_p->listen_sd, 5) < 0)
fatal_error("listen()");
}
