| /* Simple TRAU frame reflector to route voice calls */ |
| |
| /* (C) 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 <errno.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <sys/types.h> |
| |
| #include <openbsc/gsm_data.h> |
| #include <openbsc/trau_frame.h> |
| #include <openbsc/trau_mux.h> |
| #include <openbsc/subchan_demux.h> |
| #include <openbsc/e1_input.h> |
| #include <openbsc/debug.h> |
| #include <openbsc/talloc.h> |
| |
| u_int8_t gsm_fr_map[] = { |
| 6, 6, 5, 5, 4, 4, 3, 3, |
| 7, 2, 2, 6, 3, 3, 3, 3, |
| 3, 3, 3, 3, 3, 3, 3, 3, |
| 3, 7, 2, 2, 6, 3, 3, 3, |
| 3, 3, 3, 3, 3, 3, 3, 3, |
| 3, 3, 7, 2, 2, 6, 3, 3, |
| 3, 3, 3, 3, 3, 3, 3, 3, |
| 3, 3, 3, 7, 2, 2, 6, 3, |
| 3, 3, 3, 3, 3, 3, 3, 3, |
| 3, 3, 3, 3 |
| }; |
| |
| struct map_entry { |
| struct llist_head list; |
| struct gsm_e1_subslot src, dst; |
| }; |
| |
| struct upqueue_entry { |
| struct llist_head list; |
| struct gsm_network *net; |
| struct gsm_e1_subslot src; |
| u_int32_t callref; |
| }; |
| |
| static LLIST_HEAD(ss_map); |
| static LLIST_HEAD(ss_upqueue); |
| |
| void *tall_map_ctx, *tall_upq_ctx; |
| |
| /* map one particular subslot to another subslot */ |
| int trau_mux_map(const struct gsm_e1_subslot *src, |
| const struct gsm_e1_subslot *dst) |
| { |
| struct map_entry *me; |
| |
| me = talloc(tall_map_ctx, struct map_entry); |
| if (!me) { |
| LOGP(DMIB, LOGL_FATAL, "Out of memory\n"); |
| return -ENOMEM; |
| } |
| |
| DEBUGP(DCC, "Setting up TRAU mux map between (e1=%u,ts=%u,ss=%u) " |
| "and (e1=%u,ts=%u,ss=%u)\n", |
| src->e1_nr, src->e1_ts, src->e1_ts_ss, |
| dst->e1_nr, dst->e1_ts, dst->e1_ts_ss); |
| |
| /* make sure to get rid of any stale old mappings */ |
| trau_mux_unmap(src, 0); |
| trau_mux_unmap(dst, 0); |
| |
| memcpy(&me->src, src, sizeof(me->src)); |
| memcpy(&me->dst, dst, sizeof(me->dst)); |
| llist_add(&me->list, &ss_map); |
| |
| return 0; |
| } |
| |
| int trau_mux_map_lchan(const struct gsm_lchan *src, |
| const struct gsm_lchan *dst) |
| { |
| struct gsm_e1_subslot *src_ss, *dst_ss; |
| |
| src_ss = &src->ts->e1_link; |
| dst_ss = &dst->ts->e1_link; |
| |
| return trau_mux_map(src_ss, dst_ss); |
| } |
| |
| |
| /* unmap one particular subslot from another subslot */ |
| int trau_mux_unmap(const struct gsm_e1_subslot *ss, u_int32_t callref) |
| { |
| struct map_entry *me, *me2; |
| struct upqueue_entry *ue, *ue2; |
| |
| if (ss) |
| llist_for_each_entry_safe(me, me2, &ss_map, list) { |
| if (!memcmp(&me->src, ss, sizeof(*ss)) || |
| !memcmp(&me->dst, ss, sizeof(*ss))) { |
| llist_del(&me->list); |
| return 0; |
| } |
| } |
| llist_for_each_entry_safe(ue, ue2, &ss_upqueue, list) { |
| if (ue->callref == callref) { |
| llist_del(&ue->list); |
| return 0; |
| } |
| if (ss && !memcmp(&ue->src, ss, sizeof(*ss))) { |
| llist_del(&ue->list); |
| return 0; |
| } |
| } |
| return -ENOENT; |
| } |
| |
| /* look-up an enty in the TRAU mux map */ |
| static struct gsm_e1_subslot * |
| lookup_trau_mux_map(const struct gsm_e1_subslot *src) |
| { |
| struct map_entry *me; |
| |
| llist_for_each_entry(me, &ss_map, list) { |
| if (!memcmp(&me->src, src, sizeof(*src))) |
| return &me->dst; |
| if (!memcmp(&me->dst, src, sizeof(*src))) |
| return &me->src; |
| } |
| return NULL; |
| } |
| |
| /* look-up an enty in the TRAU upqueue */ |
| struct upqueue_entry * |
| lookup_trau_upqueue(const struct gsm_e1_subslot *src) |
| { |
| struct upqueue_entry *ue; |
| |
| llist_for_each_entry(ue, &ss_upqueue, list) { |
| if (!memcmp(&ue->src, src, sizeof(*src))) |
| return ue; |
| } |
| return NULL; |
| } |
| |
| static const u_int8_t c_bits_check[] = { 0, 0, 0, 1, 0 }; |
| |
| /* we get called by subchan_demux */ |
| int trau_mux_input(struct gsm_e1_subslot *src_e1_ss, |
| const u_int8_t *trau_bits, int num_bits) |
| { |
| struct decoded_trau_frame tf; |
| u_int8_t trau_bits_out[TRAU_FRAME_BITS]; |
| struct gsm_e1_subslot *dst_e1_ss = lookup_trau_mux_map(src_e1_ss); |
| struct subch_mux *mx; |
| struct upqueue_entry *ue; |
| int rc; |
| |
| /* decode TRAU, change it to downlink, re-encode */ |
| rc = decode_trau_frame(&tf, trau_bits); |
| if (rc) |
| return rc; |
| |
| if (!dst_e1_ss) { |
| struct msgb *msg; |
| struct gsm_data_frame *frame; |
| unsigned char *data; |
| int i, j, k, l, o; |
| /* frame shall be sent to upqueue */ |
| if (!(ue = lookup_trau_upqueue(src_e1_ss))) |
| return -EINVAL; |
| if (!ue->callref) |
| return -EINVAL; |
| if (memcmp(tf.c_bits, c_bits_check, sizeof(c_bits_check))) |
| DEBUGPC(DMUX, "illegal trau (C1-C5) %s\n", |
| hexdump(tf.c_bits, sizeof(c_bits_check))); |
| msg = msgb_alloc(sizeof(struct gsm_data_frame) + 33, |
| "GSM-DATA"); |
| if (!msg) |
| return -ENOMEM; |
| |
| frame = (struct gsm_data_frame *)msg->data; |
| memset(frame, 0, sizeof(struct gsm_data_frame)); |
| data = frame->data; |
| data[0] = 0xd << 4; |
| /* reassemble d-bits */ |
| i = 0; /* counts bits */ |
| j = 4; /* counts output bits */ |
| k = gsm_fr_map[0]-1; /* current number bit in element */ |
| l = 0; /* counts element bits */ |
| o = 0; /* offset input bits */ |
| while (i < 260) { |
| data[j/8] |= (tf.d_bits[k+o] << (7-(j%8))); |
| if (--k < 0) { |
| o += gsm_fr_map[l]; |
| k = gsm_fr_map[++l]-1; |
| } |
| i++; |
| j++; |
| } |
| frame->msg_type = GSM_TCHF_FRAME; |
| frame->callref = ue->callref; |
| msgb_enqueue(&ue->net->upqueue, msg); |
| |
| return 0; |
| } |
| |
| mx = e1inp_get_mux(dst_e1_ss->e1_nr, dst_e1_ss->e1_ts); |
| if (!mx) |
| return -EINVAL; |
| |
| trau_frame_up2down(&tf); |
| encode_trau_frame(trau_bits_out, &tf); |
| |
| /* and send it to the muxer */ |
| return subchan_mux_enqueue(mx, dst_e1_ss->e1_ts_ss, trau_bits_out, |
| TRAU_FRAME_BITS); |
| } |
| |
| /* add receiver instance for lchan and callref */ |
| int trau_recv_lchan(struct gsm_lchan *lchan, u_int32_t callref) |
| { |
| struct gsm_e1_subslot *src_ss; |
| struct upqueue_entry *ue; |
| |
| ue = talloc(tall_upq_ctx, struct upqueue_entry); |
| if (!ue) |
| return -ENOMEM; |
| |
| src_ss = &lchan->ts->e1_link; |
| |
| DEBUGP(DCC, "Setting up TRAU receiver (e1=%u,ts=%u,ss=%u) " |
| "and (callref 0x%x)\n", |
| src_ss->e1_nr, src_ss->e1_ts, src_ss->e1_ts_ss, |
| callref); |
| |
| /* make sure to get rid of any stale old mappings */ |
| trau_mux_unmap(src_ss, callref); |
| |
| memcpy(&ue->src, src_ss, sizeof(ue->src)); |
| ue->net = lchan->ts->trx->bts->network; |
| ue->callref = callref; |
| llist_add(&ue->list, &ss_upqueue); |
| |
| return 0; |
| } |
| |
| int trau_send_frame(struct gsm_lchan *lchan, struct gsm_data_frame *frame) |
| { |
| u_int8_t trau_bits_out[TRAU_FRAME_BITS]; |
| struct gsm_e1_subslot *dst_e1_ss = &lchan->ts->e1_link; |
| struct subch_mux *mx; |
| int i, j, k, l, o; |
| unsigned char *data = frame->data; |
| struct decoded_trau_frame tf; |
| |
| mx = e1inp_get_mux(dst_e1_ss->e1_nr, dst_e1_ss->e1_ts); |
| if (!mx) |
| return -EINVAL; |
| |
| switch (frame->msg_type) { |
| case GSM_TCHF_FRAME: |
| /* set c-bits and t-bits */ |
| tf.c_bits[0] = 1; |
| tf.c_bits[1] = 1; |
| tf.c_bits[2] = 1; |
| tf.c_bits[3] = 0; |
| tf.c_bits[4] = 0; |
| memset(&tf.c_bits[5], 0, 6); |
| memset(&tf.c_bits[11], 1, 10); |
| memset(&tf.t_bits[0], 1, 4); |
| /* reassemble d-bits */ |
| i = 0; /* counts bits */ |
| j = 4; /* counts input bits */ |
| k = gsm_fr_map[0]-1; /* current number bit in element */ |
| l = 0; /* counts element bits */ |
| o = 0; /* offset output bits */ |
| while (i < 260) { |
| tf.d_bits[k+o] = (data[j/8] >> (7-(j%8))) & 1; |
| if (--k < 0) { |
| o += gsm_fr_map[l]; |
| k = gsm_fr_map[++l]-1; |
| } |
| i++; |
| j++; |
| } |
| break; |
| default: |
| DEBUGPC(DMUX, "unsupported message type %d\n", |
| frame->msg_type); |
| return -EINVAL; |
| } |
| |
| encode_trau_frame(trau_bits_out, &tf); |
| |
| /* and send it to the muxer */ |
| return subchan_mux_enqueue(mx, dst_e1_ss->e1_ts_ss, trau_bits_out, |
| TRAU_FRAME_BITS); |
| } |