l2tp_socket: handle unix sockets using wqueue

siu/l2tp/l2tpd_socket.c

@@ -0,0 +1,113 @@
+
+#include <errno.h>
+#include <stdio.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <unistd.h>
+
+
+#include <osmocom/core/write_queue.h>
+#include <osmocom/core/logging.h>
+#include <osmocom/core/loggingrb.h>
+#include <osmocom/core/socket.h>
+
+#include "l2tpd_socket.h"
+
+/* accept a new connection */
+static int mncc_sock_accept(struct osmo_fd *bfd, unsigned int flags)
+{
+	struct l2tp_socket_state *state = container_of(bfd, struct l2tp_socket_state, listen_bfd);
+	struct osmo_fd *conn_bfd = &state->wqueue.bfd;
+	struct sockaddr_un un_addr;
+	socklen_t len;
+	int rc;
+
+	len = sizeof(un_addr);
+	rc = accept(bfd->fd, (struct sockaddr *) &un_addr, &len);
+	if (rc < 0) {
+		LOGP(state->log_class, LOGL_ERROR, "Failed to accept a new connection\n");
+		return -1;
+	}
+
+	if (conn_bfd->fd >= 0) {
+		LOGP(state->log_class, LOGL_NOTICE, "There is already one connection to the socket\n");
+		osmo_fd_unregister(conn_bfd);
+		close(conn_bfd->fd);
+		return 0;
+	}
+
+	conn_bfd->fd = rc;
+	conn_bfd->when = BSC_FD_READ | BSC_FD_WRITE;
+
+	if (osmo_fd_register(conn_bfd) != 0) {
+		LOGP(state->log_class, LOGL_ERROR, "Failed to register new connection fd\n");
+		close(conn_bfd->fd);
+		conn_bfd->fd = -1;
+		return -1;
+	}
+
+	LOGP(state->log_class, LOGL_NOTICE, "MNCC Socket has connection with external "
+		"call control application\n");
+
+	return 0;
+}
+
+void l2tp_set_read_callback(struct l2tp_socket_state *state, int (*read_cb)(struct osmo_fd *fd))
+{
+	state->wqueue.read_cb = read_cb;
+}
+
+void l2tp_set_write_callback(struct l2tp_socket_state *state, int (*write_cb)(struct osmo_fd *fd, struct msgb *msg))
+{
+	state->wqueue.write_cb = write_cb;
+}
+
+
+/*!
+ * \brief l2tp_enqueue_data
+ * \param sock
+ * \return 0 on success
+ */
+int l2tp_socket_enqueue(struct l2tp_socket_state *state, struct msgb *msg)
+{
+	return osmo_wqueue_enqueue(&state->wqueue, msg);
+}
+
+/*!
+ * \brief l2tp_socket_init
+ * \param sock
+ * \param sock_path
+ * \return 0 on success
+ */
+int l2tp_socket_init(struct l2tp_socket_state *state, const char *sock_path, int queue_len)
+{
+	struct osmo_fd *bfd;
+	int rc;
+
+	osmo_wqueue_init(&state->wqueue, queue_len);
+	state->wqueue.bfd.fd = -1;
+
+	bfd = &state->listen_bfd;
+	bfd->fd = osmo_sock_unix_init(SOCK_SEQPACKET, 0, sock_path,
+		OSMO_SOCK_F_BIND);
+	if (bfd->fd < 0) {
+		LOGP(state->log_class, LOGL_ERROR, "Could not create unix socket: %s: %s\n",
+		     sock_path, strerror(errno));
+		talloc_free(state);
+		return -1;
+	}
+
+	bfd->when = BSC_FD_READ;
+	bfd->cb = mncc_sock_accept;
+
+	rc = osmo_fd_register(bfd);
+	if (rc < 0) {
+		LOGP(state->log_class, LOGL_ERROR, "Could not register listen fd: %d\n", rc);
+		close(bfd->fd);
+		talloc_free(state);
+		return rc;
+	}
+
+	LOGP(state->log_class, LOGL_NOTICE, "MNCC socket at %s\n", sock_path);
+	return 0;
+}

siu/l2tp/l2tpd_socket.h

@@ -0,0 +1,21 @@
+#pragma once
+
+#include <osmocom/core/write_queue.h>
+
+/*!
+ * \brief The socket_state struct represents a unix socket
+ */
+struct l2tp_socket_state {
+	/*! write queue of our data socket */
+	struct osmo_wqueue wqueue;
+	/*! \brief listen_bfd listening socket*/
+	struct osmo_fd listen_bfd;
+
+	int log_class;
+};
+
+int l2tp_socket_init(struct l2tp_socket_state *state, const char *sock_path, int queue_len);
+int l2tp_socket_enqueue(struct l2tp_socket_state *state, struct msgb *msg);
+
+void l2tp_set_read_callback(struct l2tp_socket_state *state, int (*read_cb)(struct osmo_fd *fd));
+void l2tp_set_write_callback(struct l2tp_socket_state *state, int (*write_cb)(struct osmo_fd *fd, struct msgb *msg));