diff --git a/src/hnbgw.c b/src/hnbgw.c
new file mode 100644
index 0000000..fc26d0d
--- /dev/null
+++ b/src/hnbgw.c
@@ -0,0 +1,97 @@
+
+#include <osmocom/core/select.h>
+#include <osmocom/core/socket.h>
+#include <osmocom/core/linuxlist.h>
+
+#include "hnbgw.h"
+
+struct hnb_gw g_hnb_gw = {
+	.config = {
+		.iuh_listen_port = IUH_DEFAULT_SCTP_PORT,
+	},
+};
+
+static int hnb_socket_cb(struct osmo_fd *fd, unsigned int what)
+{
+	struct hnb_context *hnb = fd->data;
+	struct sctp_sndrcvinfo sinfo;
+	struct msgb *msg = msgb_alloc(IUH_MSGB_SIZE, "Iuh rx");
+	int flags;
+	int rc;
+
+	if (!msg)
+		return -ENOMEM;
+
+	rc = sctp_recvmsg(fd->fd, msgb_data(msg), msgb_tailroom(msg),
+			  NULL, NULL, &sinfo, &flags);
+	if (rc < 0) {
+		LOGP(DMAIN, LOGL_ERROR, "Error during sctp_recvmsg()\n");
+		return rc;
+	} else
+		msgb_put(msg, rc);
+
+	switch (sinfo.sinfo_ppid) {
+	case IUH_PPI_HNBAP:
+		rc = hnbgw_hnbap_rx(hnb, msg);
+		break;
+	case IUH_PPI_RUA:
+		rc = hnbgw_rua_rx(hnb, msg);
+		break;
+	case IUH_PPI_SABP:
+	case IUH_PPI_RNA:
+	case IUH_PPI_PUA:
+		LOGP(DMAIN, LOGL_ERROR, "Unimplemented SCTP PPID=%u received\n",
+		     sinfo.sinfo_ppid);
+		rc = 0;
+		break;
+	default:
+		LOGP(DMAIN, LOGL_ERROR, "Unknown SCTP PPID=%u received\n",
+		     sinfo.sinfo_ppid);
+		rc = 0;
+		break;
+	}
+
+	return rc;
+}
+
+/*! call-back when the listen FD has something to read */
+static int listen_fd_cb(struct osmo_fd *fd, unsigned int what)
+{
+	struct hnb_gw *gw = fd->data;
+	struct hmb_context *ctx;
+	struct sokaddr_storage sockaddr;
+	socklen_t len = sizeof(sockaddr);
+
+	int new_fd = accept(fd->fd, (struct sockaddr *)&sockaddr, &len);
+	if (new_fd < 0) {
+		LOGP(DMAIN, LOGL_ERROR, "Iuh accept() failed\n");
+		return new_fd;
+	}
+
+	LOGP(DMAIN, LOGL_INFO, "SCTP Connection accept()ed\n");
+
+	ctx = talloc_zero(tall_hnb_ctx, struct hnb_context);
+	if (!ctx)
+		return -ENOMEM;
+
+	ctx->gw = gw;
+	ctx->socket.data = ctx;
+	ctx->socket.fd = new_fd;
+	ctx->socket.when = BSC_FD_READ;
+	ctx->socket.cb = hnb_socket_cb;
+	osmo_fd_register(&cttx->socket);
+
+	return 0;
+}
+
+
+
+{
+	g_hnb_gw.listen_fd.cb = listen_fd_cb;
+	g_hnb_gw.listen_fd.when = BSC_FD_READ;
+	g_hnb_gw.listen_fd.data = &g_hnb_gw;
+
+	osmo_sock_init_ofd(&g_hnb_gw.listen_fd, AF_INET, SOCK_STREAM,
+			   IPPROTO_SCTP, "127.0.0.1",
+			   g_hnb_gw.config.iuh_listen_port, OSMO_SOCK_F_BIND);
+}