1 files changed, 67 insertions, 0 deletions
diff --git a/bus.c b/bus.c
new file mode 100644
index 0000000..7b4d01d
--- /dev/null
+++ b/bus.c
@@ -0,0 +1,67 @@
+#include <signal.h>
+#include <arpa/inet.h>
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <poll.h>
+
+err(), warn(), warnx(), read(), write(), close();
+
+#define SOCKETS_MAX 128
+#define BUFFER_SIZE 512
+
+#define lengthof(X) (sizeof(X) / sizeof(*(X)))
+
+main(argc, argv) char **argv;
+{
+	struct sockaddr_in addr = {AF_INET, htons(8604), htonl(INADDR_ANY)};
+	struct pollfd ppeers[SOCKETS_MAX] = {0};
+	int peers[SOCKETS_MAX] = {0}, client, i, j, written, readed;
+	char buf[BUFFER_SIZE] = {0};
+
+	for (
+		argc > 1 && (addr.sin_port = htons(atoi(argv[1]))),
+		argc > 2 && inet_pton(AF_INET, argv[1], &addr.sin_addr) == -1 && err(1, "inet_pton()"),
+		(peers[0] = socket(AF_INET, SOCK_STREAM, 0)) == -1 && err(1, "socket()"),
+		setsockopt(peers[0], SOL_SOCKET, SO_REUSEADDR, &(int){1}, sizeof(int)) == -1 && err(1, "setsockopt()"),
+		bind(peers[0], (void *)&addr, sizeof(addr)) == -1 && err(1, "bind()"),
+		listen(peers[0], 16) == -1 && err(1, "listen()"),
+		signal(SIGPIPE, SIG_IGN);
+	;)
+	{
+		for (written = i = 0; i < lengthof(peers) ? (peers[i] && ((ppeers[written++] = (struct pollfd){peers[i], POLLIN}), 0), 1) : 0; ++i)
+			if (i + 1 == lengthof(peers))
+				for (
+				client = 0, j = 1, poll(ppeers, written, -1) == -1 && err(1, "poll");
+				ppeers[0].revents & POLLIN &&
+				(client ? client : (client = accept(peers[0], 0, 0))) == -1
+				?	(warn("accept()"), 0)
+				:	(
+					j < lengthof(peers)
+					?	(!peers[j] ? ((peers[j] = client), 0) : 1)
+					:	1
+				);
+				++j
+				)
+					if (j + 1 == lengthof(peers))
+						warnx("dropping %d as peer list is full", client),
+						close(client);
+		for (i = 1; i < written; ++i)
+			if (ppeers[i].revents & POLLIN)
+				for (
+				readed = read(ppeers[i].fd, buf, sizeof(buf)),
+				j = 1;
+				j < lengthof(peers)
+				?	(
+					readed == -1 || !readed
+					?	(
+						ppeers[i].fd == peers[j]
+						?	(close(peers[j]), peers[j] = 0)
+						:	1
+					)
+					:	(peers[j] && ppeers[i].fd != peers[j] && write(peers[j], buf, readed), 1)
+				)
+				:	0;
+				++j
+				);
+	}
+}