#include <sys/types.h>
#include <sys/socket.h>
+#include <netdb.h>
#include <netinet/in.h>
#include <errno.h>
/* Server */
int socket_fd;
- struct sockaddr_in server_addr;
+ struct addrinfo* addresses;
+ struct addrinfo* current_address;
+ char bound_address[1024];
+ char bound_port[64];
int opt_on = 1;
/* Client */
int connected_socket_fd;
/* Arguments */
- int listen_port = 4822; /* Default port */
+ char* listen_address = NULL; /* Default address of INADDR_ANY */
+ char* listen_port = "4822"; /* Default port */
+ char* pidfile = NULL;
int opt;
- char* pidfile = NULL;
+ /* General */
+ int retval;
/* Daemon Process */
pid_t daemon_pid;
/* Parse arguments */
- while ((opt = getopt(argc, argv, "l:p:")) != -1) {
+ while ((opt = getopt(argc, argv, "l:b:p:")) != -1) {
if (opt == 'l') {
- listen_port = atoi(optarg);
- if (listen_port <= 0) {
- fprintf(stderr, "Invalid port: %s\n", optarg);
- exit(EXIT_FAILURE);
- }
+ listen_port = strdup(optarg);
+ }
+ else if (opt == 'b') {
+ listen_address = strdup(optarg);
}
else if (opt == 'p') {
pidfile = strdup(optarg);
}
else {
- fprintf(stderr, "USAGE: %s [-l LISTENPORT] [-p PIDFILE]\n", argv[0]);
+
+ fprintf(stderr, "USAGE: %s"
+ " [-l LISTENPORT]"
+ " [-b LISTENADDRESS]"
+ " [-p PIDFILE]\n", argv[0]);
+
exit(EXIT_FAILURE);
}
}
- /* Get binding address */
- memset(&server_addr, 0, sizeof(server_addr)); /* Zero struct */
- server_addr.sin_family = AF_INET;
- server_addr.sin_addr.s_addr = INADDR_ANY;
- server_addr.sin_port = htons(listen_port);
+ /* Get addresses for binding */
+ if ((retval = getaddrinfo(listen_address, listen_port, NULL, &addresses))) {
+ fprintf(stderr, "Error parsing given address or port: %s\n",
+ gai_strerror(retval));
+ exit(EXIT_FAILURE);
+ }
/* Get socket */
socket_fd = socket(AF_INET, SOCK_STREAM, 0);
exit(EXIT_FAILURE);
}
+ /* Allow socket reuse */
if (setsockopt(socket_fd, SOL_SOCKET, SO_REUSEADDR, (void*) &opt_on, sizeof(opt_on))) {
fprintf(stderr, "Warning: Unable to set socket options for reuse: %s\n", strerror(errno));
}
- /* Bind socket to address */
- if (bind(socket_fd, (struct sockaddr*) &server_addr,
- sizeof(server_addr)) < 0) {
- fprintf(stderr, "Error binding socket: %s\n", strerror(errno));
+ /* Attempt binding of each address until success */
+ current_address = addresses;
+ while (current_address != NULL) {
+
+ /* Attempt to bind socket to address */
+ if (bind(socket_fd,
+ current_address->ai_addr,
+ current_address->ai_addrlen) == 0) {
+
+ /* Done if successful bind */
+ break;
+
+ }
+
+ /* Otherwise log error */
+ else
+ fprintf(stderr, "Error binding socket: %s\n", strerror(errno));
+
+ current_address = current_address->ai_next;
+
+ }
+
+ /* If unable to bind to anything, fail */
+ if (current_address == NULL) {
+ fprintf(stderr, "Unable to bind socket to any addresses.\n");
exit(EXIT_FAILURE);
- }
+ }
/* Fork into background */
daemon_pid = fork();
/* Open log */
openlog(NULL, LOG_PID, LOG_DAEMON);
- /* Otherwise, this is the daemon */
- syslog(LOG_INFO, "Listening on port %i", listen_port);
-
/* Ignore SIGPIPE */
if (signal(SIGPIPE, SIG_IGN) == SIG_ERR) {
syslog(LOG_ERR, "Could not set handler for SIGPIPE to ignore. SIGPIPE may cause termination of the daemon.");
syslog(LOG_ERR, "Could not set handler for SIGCHLD to ignore. Child processes may pile up in the process table.");
}
+ /* Log address and port */
+ if (getnameinfo(current_address->ai_addr, current_address->ai_addrlen,
+ bound_address, sizeof(bound_address),
+ bound_port, sizeof(bound_port),
+ 0))
+ syslog(LOG_WARNING, "Could not resolve name of listening host.");
+ else
+ syslog(LOG_INFO,
+ "Listening on host %s, port %s", bound_address, bound_port);
+
+ /* Free addresses */
+ freeaddrinfo(addresses);
+
/* Daemon loop */
for (;;) {