131 lines
3.5 KiB
C
131 lines
3.5 KiB
C
/* Routines for a Virtual Um interface over GSMTAP/UDP */
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/* (C) 2015 by Harald Welte <laforge@gnumonks.org>
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*
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* All Rights Reserved
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include <osmocom/core/select.h>
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#include <osmocom/core/utils.h>
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#include <osmocom/core/socket.h>
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#include <osmocom/core/gsmtap.h>
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#include <osmocom/core/msgb.h>
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#include <osmocom/core/talloc.h>
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#include "osmo_mcast_sock.h"
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#include "virtual_um.h"
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#include <unistd.h>
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#include <errno.h>
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/**
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* Virtual UM interface file descriptor callback.
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* Should be called by select.c when the fd is ready for reading.
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*/
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static int virt_um_fd_cb(struct osmo_fd *ofd, unsigned int what)
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{
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struct virt_um_inst *vui = ofd->data;
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if (what & OSMO_FD_READ) {
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struct msgb *msg = msgb_alloc(VIRT_UM_MSGB_SIZE, "Virtual UM Rx");
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int rc;
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/* read message from fd into message buffer */
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rc = mcast_bidir_sock_rx(vui->mcast_sock, msgb_data(msg), msgb_tailroom(msg));
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if (rc > 0) {
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msgb_put(msg, rc);
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msg->l1h = msgb_data(msg);
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/* call the l1 callback function for a received msg */
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vui->recv_cb(vui, msg);
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} else if (rc == 0) {
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vui->recv_cb(vui, NULL);
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osmo_fd_close(ofd);
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} else
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perror("Read from multicast socket");
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}
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return 0;
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}
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struct virt_um_inst *virt_um_init(void *ctx, char *tx_mcast_group, uint16_t tx_mcast_port,
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char *rx_mcast_group, uint16_t rx_mcast_port, int ttl, const char *dev_name,
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void (*recv_cb)(struct virt_um_inst *vui, struct msgb *msg))
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{
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struct virt_um_inst *vui = talloc_zero(ctx, struct virt_um_inst);
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int rc;
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vui->mcast_sock = mcast_bidir_sock_setup(ctx, tx_mcast_group, tx_mcast_port,
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rx_mcast_group, rx_mcast_port, 1, virt_um_fd_cb, vui);
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if (!vui->mcast_sock) {
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perror("Unable to create VirtualUm multicast socket");
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talloc_free(vui);
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return NULL;
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}
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vui->recv_cb = recv_cb;
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/* -1 means default, i.e. no TTL explicitly configured in VTY */
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if (ttl >= 0) {
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rc = osmo_sock_mcast_ttl_set(vui->mcast_sock->tx_ofd.fd, ttl);
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if (rc < 0) {
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perror("Cannot set TTL of Virtual Um transmit socket");
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goto out_close;
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}
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}
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if (dev_name) {
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rc = osmo_sock_mcast_iface_set(vui->mcast_sock->tx_ofd.fd, dev_name);
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if (rc < 0) {
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perror("Cannot bind multicast tx to given device");
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goto out_close;
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}
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rc = osmo_sock_mcast_iface_set(vui->mcast_sock->rx_ofd.fd, dev_name);
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if (rc < 0) {
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perror("Cannot bind multicast rx to given device");
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goto out_close;
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}
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}
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return vui;
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out_close:
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mcast_bidir_sock_close(vui->mcast_sock);
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talloc_free(vui);
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return NULL;
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}
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void virt_um_destroy(struct virt_um_inst *vui)
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{
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mcast_bidir_sock_close(vui->mcast_sock);
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talloc_free(vui);
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}
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/**
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* Write msg to to multicast socket and free msg afterwards
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*/
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int virt_um_write_msg(struct virt_um_inst *vui, struct msgb *msg)
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{
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int rc;
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rc = mcast_bidir_sock_tx(vui->mcast_sock, msgb_data(msg),
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msgb_length(msg));
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if (rc < 0)
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rc = -errno;
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msgb_free(msg);
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return rc;
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}
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