/******************************************************************************/
/* */
/* Copyright (c) International Business Machines Corp., 2005 */
/* */
/* This program is free software; you can redistribute it and/or modify */
/* it under the terms of the GNU General Public License as published by */
/* the Free Software Foundation; either version 2 of the License, or */
/* (at your option) any later version. */
/* */
/* This program is distributed in the hope that it will be useful, */
/* but WITHOUT ANY WARRANTY; without even the implied warranty of */
/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See */
/* the GNU General Public License for more details. */
/* */
/* You should have received a copy of the GNU General Public License */
/* along with this program; if not, write to the Free Software */
/* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */
/* */
/******************************************************************************/
/*
* File:
* ns-udpserver.c
*
* Description:
* This is UDP traffic server.
* Received UDP datagram from a client, then send it to the client
*
* Author:
* Mitsuru Chinen <mitch@jp.ibm.com>
*
* History:
* Oct 19 2005 - Created (Mitsuru Chinen)
*---------------------------------------------------------------------------*/
#include "ns-traffic.h"
/*
* Standard Include Files
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <netdb.h>
#include <time.h>
#include <unistd.h>
#include <sys/select.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <netinet/in.h>
/*
* Gloval variables
*/
struct sigaction handler; /* Behavior for a signal */
int catch_sighup; /* When catch the SIGHUP, set to non-zero */
/*
* Function: usage()
*
* Descripton:
* Print the usage of this program. Then, terminate this program with
* the specified exit value.
*
* Argument:
* exit_value: exit value
*
* Return value:
* This function does not return.
*/
void usage(char *program_name, int exit_value)
{
FILE *stream = stdout; /* stream where the usage is output */
if (exit_value == EXIT_FAILURE)
stream = stderr;
fprintf(stream, "%s [OPTION]\n"
"\t-f\tprotocol family\n"
"\t\t 4 : IPv4\n"
"\t\t 6 : IPv6\n"
"\t-p\tport number\n"
"\t\tthe port number specified by -p option would be the first port number\n"
"\t-b\twork in the background\n"
"\t-o\tfilename where the server infomation is outputted\n"
"\t-d\twork in the debug mode\n"
"\t-h\tdisplay this usage\n"
"" "*) Server works till it receives SIGHUP\n", program_name);
exit(exit_value);
}
/*
* Function: set_signal_flag()
*
* Description:
* This function sets global variable according to the signal.
* Once a signal is caught, the signal is ignored after that.
*
* Argument:
* type: type of signal
*
* Return value:
* None
*/
void set_signal_flag(int type)
{
/* Set SIG_IGN against the caught signal */
handler.sa_handler = SIG_IGN;
if (sigaction(type, &handler, NULL) < 0)
fatal_error("sigaction()");
if (debug)
fprintf(stderr, "Catch signal. type is %d\n", type);
switch (type) {
case SIGHUP:
catch_sighup = 1;
break;
default:
fprintf(stderr, "Unexpected signal (%d) is caught\n", type);
exit(EXIT_FAILURE);
}
}
/*
* Function: respond_to_client()
*
* Description:
* Recieve the client data. Then, return the data to client.
*
* Argument:
* sock_fd: socket file descriptor
*
* Return value:
* None
*/
void respond_to_client(sock_fd)
{
char *msgbuf; /* Pointer to the message */
size_t msgbuf_size; /* size of msgbuf */
ssize_t msglen; /* the length of message */
socklen_t sock_optlen; /* size of the result parameter */
struct sockaddr_storage client_addr; /* address of a client */
socklen_t client_addr_len; /* length of `client_addr' */
sock_optlen = sizeof(sock_optlen);
if (getsockopt(sock_fd, SOL_SOCKET, SO_RCVBUF,
&msgbuf_size, &sock_optlen) < 0) {
perror("getsockopt()");
close(sock_fd);
exit(EXIT_FAILURE);
}
/* Allocate the memory for a message */
msgbuf = malloc(msgbuf_size + 1);
if (msgbuf == NULL) {
fprintf(stderr, "malloc() is failed.\n");
close(sock_fd);
exit(EXIT_FAILURE);
}
/* Receive a message */
client_addr_len = sizeof(client_addr);
if ((msglen = recvfrom(sock_fd, msgbuf, msgbuf_size, 0,
(struct sockaddr *)&client_addr,
&client_addr_len)) < 0)
fatal_error("recvfrom()");
msgbuf[msglen] = '\0';
if (debug)
fprintf(stderr, "Message is %s\n", msgbuf);
/* Return the message to the client */
if (sendto(sock_fd, msgbuf, msglen, 0,
(struct sockaddr *)&client_addr,
sizeof(client_addr)) != msglen)
fatal_error("sendto()");
free(msgbuf);
}
/*
*
* Function: main()
*
*/
int main(int argc, char *argv[])
{
char *program_name = argv[0];
int optc; /* option */
sa_family_t family; /* protocol family */
char *portnum = NULL; /* port number */
int sock_fd; /* socket binded open ports */
int background = 0; /* work in the background if non-zero */
fd_set read_fds; /* list of file descriptor for reading */
int max_read_fd = 0; /* maximum number in the read fds */
FILE *info_fp = stdout; /* FILE pointer to a information file */
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 */
debug = 0;
family = PF_UNSPEC;
/* Retrieve the options */
while ((optc = getopt(argc, argv, "f:p:bo:dh")) != EOF) {
switch (optc) {
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 num;
num = strtoul(optarg, NULL, 0);
if (num < PORTNUMMIN || PORTNUMMAX < num) {
fprintf(stderr,
"The range of port is from %u to %u\n",
PORTNUMMIN, PORTNUMMAX);
usage(program_name, EXIT_FAILURE);
}
portnum = strdup(optarg);
}
break;
case 'b':
background = 1;
break;
case 'o':
if ((info_fp = fopen(optarg, "w")) == NULL) {
fprintf(stderr, "Cannot open %s\n", optarg);
exit(EXIT_FAILURE);
}
break;
case 'd':
debug = 1;
break;
case 'h':
usage(program_name, EXIT_SUCCESS);
break;
default:
usage(program_name, EXIT_FAILURE);
}
}
/* Check the family is spefied. */
if (family == PF_UNSPEC) {
fprintf(stderr, "protocol family should be specified.\n");
usage(program_name, EXIT_FAILURE);
}
/* At first, SIGHUP is ignored. */
handler.sa_handler = SIG_IGN;
if (sigfillset(&handler.sa_mask) < 0)
fatal_error("sigfillset()");
handler.sa_flags = 0;
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_DGRAM;
hints.ai_protocol = IPPROTO_UDP;
hints.ai_flags = AI_PASSIVE;
/* Translate the network and service information of the server */
err = getaddrinfo(NULL, 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. */
sock_fd = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
if (sock_fd < 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
(sock_fd, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(int)))
fatal_error("setsockopt()");
}
#endif
/* Enable to reuse the socket */
on = 1;
if (setsockopt(sock_fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(int)))
fatal_error("setsockopt()");
/* Bind to the local address */
if (bind(sock_fd, res->ai_addr, res->ai_addrlen) < 0)
fatal_error("bind()");
freeaddrinfo(res);
/* If -b option is specified, work as a daemon */
if (background)
if (daemon(0, 0) < 0)
fatal_error("daemon()");
/* Output any server information to the information file */
fprintf(info_fp, "PID: %u\n", getpid());
fflush(info_fp);
if (info_fp != stdout)
if (fclose(info_fp))
fatal_error("fclose()");
/* Catch SIGHUP */
handler.sa_handler = set_signal_flag;
if (sigaction(SIGHUP, &handler, NULL) < 0)
fatal_error("sigaction()");
/* Loop to wait a client access */
FD_ZERO(&read_fds);
FD_SET(sock_fd, &read_fds);
max_read_fd = sock_fd;
for (;;) {
int select_ret; /* return value of select() */
fd_set active_fds; /* list of the active file descriptor */
struct timeval select_timeout; /* timeout for select() */
/* When catch SIGHUP, exit the loop */
if (catch_sighup)
break;
active_fds = read_fds;
select_timeout.tv_sec = 0; /* 0.5 sec */
select_timeout.tv_usec = 500000;
select_ret = select(max_read_fd + 1, &active_fds,
NULL, NULL, &select_timeout);
if (select_ret < 0) {
if (catch_sighup)
break;
else
fatal_error("select()");
} else if (select_ret == 0) {
continue;
} else {
if (FD_ISSET(sock_fd, &active_fds))
respond_to_client(sock_fd);
}
}
/* Close the sockets */
if (close(sock_fd))
fatal_error("close()");
exit(EXIT_SUCCESS);
}