diff options
Diffstat (limited to 'openbsc/src/rs232.c')
| -rw-r--r-- | openbsc/src/rs232.c | 249 |
1 files changed, 249 insertions, 0 deletions
diff --git a/openbsc/src/rs232.c b/openbsc/src/rs232.c new file mode 100644 index 000000000..2a64de5ef --- /dev/null +++ b/openbsc/src/rs232.c @@ -0,0 +1,249 @@ +/* OpenBSC BS-11 T-Link interface using POSIX serial port */ + +/* (C) 2008-2009 by Harald Welte <laforge@gnumonks.org> + * + * All Rights Reserved + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + * + */ + +#include <unistd.h> +#include <stdlib.h> +#include <stdio.h> +#include <errno.h> +#include <string.h> +#include <termios.h> +#include <fcntl.h> + +#include <openbsc/select.h> +#include <openbsc/msgb.h> +#include <openbsc/debug.h> +#include <openbsc/gsm_data.h> +#include <openbsc/rs232.h> + +/* adaption layer from GSM 08.59 + 12.21 to RS232 */ + +struct serial_handle { + struct bsc_fd fd; + struct llist_head tx_queue; + + struct msgb *rx_msg; + unsigned int rxmsg_bytes_missing; + + unsigned int delay_ms; + struct gsm_bts *bts; +}; + +/* FIXME: this needs to go */ +static struct serial_handle _ser_handle, *ser_handle = &_ser_handle; + +#define LAPD_HDR_LEN 10 + +static int handle_ser_write(struct bsc_fd *bfd); + +/* callback from abis_nm */ +int _abis_nm_sendmsg(struct msgb *msg) +{ + struct serial_handle *sh = ser_handle; + u_int8_t *lapd; + unsigned int len; + + msg->l2h = msg->data; + + /* prepend LAPD header */ + lapd = msgb_push(msg, LAPD_HDR_LEN); + + len = msg->len - 2; + + lapd[0] = (len >> 8) & 0xff; + lapd[1] = len & 0xff; /* length of bytes startign at lapd[2] */ + lapd[2] = 0x00; + lapd[3] = 0x07; + lapd[4] = 0x01; + lapd[5] = 0x3e; + lapd[6] = 0x00; + lapd[7] = 0x00; + lapd[8] = msg->len - 10; /* length of bytes starting at lapd[10] */ + lapd[9] = lapd[8] ^ 0x38; + + msgb_enqueue(&sh->tx_queue, msg); + sh->fd.when |= BSC_FD_WRITE; + + /* we try to immediately send */ + handle_ser_write(&sh->fd); + + return 0; +} + +/* select.c callback in case we can write to the RS232 */ +static int handle_ser_write(struct bsc_fd *bfd) +{ + struct serial_handle *sh = bfd->data; + struct msgb *msg; + int written; + + msg = msgb_dequeue(&sh->tx_queue); + if (!msg) { + bfd->when &= ~BSC_FD_WRITE; + return 0; + } + + DEBUGP(DMI, "RS232 TX: %s\n", hexdump(msg->data, msg->len)); + + /* send over serial line */ + written = write(bfd->fd, msg->data, msg->len); + if (written < msg->len) { + perror("short write:"); + msgb_free(msg); + return -1; + } + + msgb_free(msg); + usleep(sh->delay_ms*1000); + + return 0; +} + +#define SERIAL_ALLOC_SIZE 300 + +/* select.c callback in case we can read from the RS232 */ +static int handle_ser_read(struct bsc_fd *bfd) +{ + struct serial_handle *sh = bfd->data; + struct msgb *msg; + int rc = 0; + + if (!sh->rx_msg) { + sh->rx_msg = msgb_alloc(SERIAL_ALLOC_SIZE); + sh->rx_msg->l2h = NULL; + sh->rx_msg->trx = sh->bts->c0; + } + msg = sh->rx_msg; + + /* first read two byes to obtain length */ + if (msg->len < 2) { + rc = read(sh->fd.fd, msg->tail, 2 - msg->len); + if (rc < 0) { + perror("ERROR reading from serial port"); + msgb_free(msg); + return rc; + } + msgb_put(msg, rc); + + if (msg->len >= 2) { + /* parse LAPD payload length */ + if (msg->data[0] != 0) + fprintf(stderr, "Suspicious header byte 0: 0x%02x\n", + msg->data[0]); + + sh->rxmsg_bytes_missing = msg->data[0] << 8; + sh->rxmsg_bytes_missing += msg->data[1]; + + if (sh->rxmsg_bytes_missing < LAPD_HDR_LEN -2) + fprintf(stderr, "Invalid length in hdr: %u\n", + sh->rxmsg_bytes_missing); + } + } else { + /* try to read as many of the missing bytes as are available */ + rc = read(sh->fd.fd, msg->tail, sh->rxmsg_bytes_missing); + if (rc < 0) { + perror("ERROR reading from serial port"); + msgb_free(msg); + return rc; + } + msgb_put(msg, rc); + sh->rxmsg_bytes_missing -= rc; + + if (sh->rxmsg_bytes_missing == 0) { + /* we have one complete message now */ + sh->rx_msg = NULL; + + if (msg->len > LAPD_HDR_LEN) + msg->l2h = msg->data + LAPD_HDR_LEN; + + DEBUGP(DMI, "RS232 RX: %s\n", hexdump(msg->data, msg->len)); + rc = handle_serial_msg(msg); + } + } + + return rc; +} + +/* select.c callback */ +static int serial_fd_cb(struct bsc_fd *bfd, unsigned int what) +{ + int rc = 0; + + if (what & BSC_FD_READ) + rc = handle_ser_read(bfd); + + if (rc < 0) + return rc; + + if (what & BSC_FD_WRITE) + rc = handle_ser_write(bfd); + + return rc; +} + +int rs232_setup(const char *serial_port, unsigned int delay_ms, + struct gsm_bts *bts) +{ + int rc, serial_fd; + struct termios tio; + + serial_fd = open(serial_port, O_RDWR); + if (serial_fd < 0) { + perror("cannot open serial port:"); + return serial_fd; + } + + /* set baudrate */ + rc = tcgetattr(serial_fd, &tio); + if (rc < 0) { + perror("tcgetattr()"); + return rc; + } + cfsetispeed(&tio, B19200); + cfsetospeed(&tio, B19200); + tio.c_cflag |= (CREAD | CLOCAL | CS8); + tio.c_cflag &= ~(PARENB | CSTOPB | CSIZE | CRTSCTS); + tio.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG); + tio.c_iflag |= (INPCK | ISTRIP); + tio.c_iflag &= ~(ISTRIP | IXON | IXOFF | IGNBRK | INLCR | ICRNL | IGNCR); + tio.c_oflag &= ~(OPOST); + rc = tcsetattr(serial_fd, TCSADRAIN, &tio); + if (rc < 0) { + perror("tcsetattr()"); + return rc; + } + + INIT_LLIST_HEAD(&ser_handle->tx_queue); + ser_handle->fd.fd = serial_fd; + ser_handle->fd.when = BSC_FD_READ; + ser_handle->fd.cb = serial_fd_cb; + ser_handle->fd.data = ser_handle; + ser_handle->delay_ms = delay_ms; + ser_handle->bts = bts; + rc = bsc_register_fd(&ser_handle->fd); + if (rc < 0) { + fprintf(stderr, "could not register FD: %s\n", + strerror(rc)); + return rc; + } + + return 0; +} |