1 /* Layer1 control code, talking L1CTL protocol with L1 on the phone */
3 /* (C) 2010 by Holger Hans Peter Freyther <zecke@selfish.org>
4 * (C) 2010 by Harald Welte <laforge@gnumonks.org>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License along
19 * with this program; if not, write to the Free Software Foundation, Inc.,
20 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
29 #include <arpa/inet.h>
31 #include <l1a_l23_interface.h>
33 #include <osmocore/logging.h>
34 #include <osmocore/timer.h>
35 #include <osmocore/msgb.h>
36 #include <osmocore/tlv.h>
37 #include <osmocore/gsm_utils.h>
38 #include <osmocore/protocol/gsm_04_08.h>
39 #include <osmocore/protocol/gsm_08_58.h>
40 #include <osmocore/rsl.h>
42 #include <osmocom/l1ctl.h>
43 #include <osmocom/osmocom_data.h>
44 #include <osmocom/lapdm.h>
45 #include <osmocom/logging.h>
46 #include <osmocom/gsmtap_util.h>
48 static struct msgb *osmo_l1_alloc(uint8_t msg_type)
50 struct l1ctl_hdr *l1h;
51 struct msgb *msg = msgb_alloc_headroom(256, 4, "osmo_l1");
54 LOGP(DL1C, LOGL_ERROR, "Failed to allocate memory.\n");
58 msg->l1h = msgb_put(msg, sizeof(*l1h));
59 l1h = (struct l1ctl_hdr *) msg->l1h;
60 l1h->msg_type = msg_type;
66 static int osmo_make_band_arfcn(struct osmocom_ms *ms)
68 /* TODO: Include the band */
72 static int rx_l1_ccch_resp(struct osmocom_ms *ms, struct msgb *msg)
74 struct l1ctl_info_dl *dl;
75 struct l1ctl_sync_new_ccch_resp *sb;
78 if (msgb_l3len(msg) < sizeof(*sb)) {
79 LOGP(DL1C, LOGL_ERROR, "MSG too short for CCCH RESP: %u\n",
84 dl = (struct l1ctl_info_dl *) msg->l1h;
85 sb = (struct l1ctl_sync_new_ccch_resp *) dl->payload;
87 gsm_fn2gsmtime(&tm, ntohl(dl->frame_nr));
88 DEBUGP(DL1C, "SCH: SNR: %u TDMA: (%.4u/%.2u/%.2u) bsic: %d\n",
89 dl->snr, tm.t1, tm.t2, tm.t3, sb->bsic);
94 char *chan_nr2string(uint8_t chan_nr)
97 uint8_t cbits = chan_nr >> 3;
102 sprintf(str, "TCH/F");
103 else if ((cbits & 0x1e) == 0x02)
104 sprintf(str, "TCH/H(%u)", cbits & 0x01);
105 else if ((cbits & 0x1c) == 0x04)
106 sprintf(str, "SDCCH/4(%u)", cbits & 0x03);
107 else if ((cbits & 0x18) == 0x08)
108 sprintf(str, "SDCCH/8(%u)", cbits & 0x07);
109 else if (cbits == 0x10)
110 sprintf(str, "BCCH");
111 else if (cbits == 0x11)
112 sprintf(str, "RACH");
113 else if (cbits == 0x12)
114 sprintf(str, "PCH/AGCH");
116 sprintf(str, "UNKNOWN");
121 /* Receive L1CTL_DATA_IND (Data Indication from L1) */
122 static int rx_ph_data_ind(struct osmocom_ms *ms, struct msgb *msg)
124 struct l1ctl_info_dl *dl, dl_cpy;
125 struct l1ctl_data_ind *ccch;
126 struct lapdm_entity *le;
127 uint8_t chan_type, chan_ts, chan_ss;
128 uint8_t gsmtap_chan_type;
131 if (msgb_l3len(msg) < sizeof(*ccch)) {
132 LOGP(DL1C, LOGL_ERROR, "MSG too short Data Ind: %u\n",
137 dl = (struct l1ctl_info_dl *) msg->l1h;
138 msg->l2h = dl->payload;
139 ccch = (struct l1ctl_data_ind *) msg->l2h;
141 gsm_fn2gsmtime(&tm, ntohl(dl->frame_nr));
142 rsl_dec_chan_nr(dl->chan_nr, &chan_type, &chan_ss, &chan_ts);
143 DEBUGP(DL1C, "%s (%.4u/%.2u/%.2u) %s\n",
144 chan_nr2string(dl->chan_nr), tm.t1, tm.t2, tm.t3,
145 hexdump(ccch->data, sizeof(ccch->data)));
147 /* send CCCH data via GSMTAP */
148 gsmtap_chan_type = chantype_rsl2gsmtap(chan_type, dl->link_id);
149 gsmtap_sendmsg(dl->band_arfcn, chan_ts, gsmtap_chan_type, chan_ss,
150 tm.fn, dl->rx_level-110, dl->snr, ccch->data,
153 /* determine LAPDm entity based on SACCH or not */
154 if (dl->link_id & 0x40)
155 le = &ms->lapdm_acch;
157 le = &ms->lapdm_dcch;
158 /* make local stack copy of l1ctl_info_dl, as LAPDm will
159 * overwrite skb hdr */
160 memcpy(&dl_cpy, dl, sizeof(dl_cpy));
162 /* pull the L1 header from the msgb */
163 msgb_pull(msg, msg->l2h - (msg->l1h-sizeof(struct l1ctl_hdr)));
166 /* send it up into LAPDm */
167 l2_ph_data_ind(msg, le, &dl_cpy);
172 /* Transmit L1CTL_DATA_REQ */
173 int tx_ph_data_req(struct osmocom_ms *ms, struct msgb *msg,
174 uint8_t chan_nr, uint8_t link_id)
176 struct l1ctl_hdr *l1h;
177 struct l1ctl_info_ul *l1i_ul;
178 uint8_t chan_type, chan_ts, chan_ss;
179 uint8_t gsmtap_chan_type;
181 DEBUGP(DL1C, "(%s)\n", hexdump(msg->l2h, msgb_l2len(msg)));
183 if (msgb_l2len(msg) > 23) {
184 LOGP(DL1C, LOGL_ERROR, "L1 cannot handle message length "
185 "> 23 (%u)\n", msgb_l2len(msg));
188 } else if (msgb_l2len(msg) < 23)
189 LOGP(DL1C, LOGL_ERROR, "L1 message length < 23 (%u) "
190 "doesn't seem right!\n", msgb_l2len(msg));
192 /* send copy via GSMTAP */
193 rsl_dec_chan_nr(chan_nr, &chan_type, &chan_ss, &chan_ts);
194 gsmtap_chan_type = chantype_rsl2gsmtap(chan_type, link_id);
195 gsmtap_sendmsg(0|0x4000, chan_ts, gsmtap_chan_type, chan_ss,
196 0, 127, 255, msg->l2h, msgb_l2len(msg));
198 /* prepend uplink info header */
199 l1i_ul = (struct l1ctl_info_ul *) msgb_push(msg, sizeof(*l1i_ul));
201 l1i_ul->chan_nr = chan_nr;
202 l1i_ul->link_id = link_id;
204 /* FIXME: where to get this from? */
205 l1i_ul->tx_power = 0;
207 /* prepend l1 header */
208 msg->l1h = msgb_push(msg, sizeof(*l1h));
209 l1h = (struct l1ctl_hdr *) msg->l1h;
210 l1h->msg_type = L1CTL_DATA_REQ;
212 return osmo_send_l1(ms, msg);
215 /* Receive L1CTL_RESET */
216 static int rx_l1_reset(struct osmocom_ms *ms)
219 struct l1ctl_sync_new_ccch_req *req;
221 msg = osmo_l1_alloc(L1CTL_NEW_CCCH_REQ);
225 LOGP(DL1C, LOGL_INFO, "Layer1 Reset.\n");
226 req = (struct l1ctl_sync_new_ccch_req *) msgb_put(msg, sizeof(*req));
227 req->band_arfcn = osmo_make_band_arfcn(ms);
229 return osmo_send_l1(ms, msg);
232 /* Transmit L1CTL_RACH_REQ */
233 int tx_ph_rach_req(struct osmocom_ms *ms)
236 struct l1ctl_info_ul *ul;
237 struct l1ctl_rach_req *req;
238 static uint8_t i = 0;
240 msg = osmo_l1_alloc(L1CTL_RACH_REQ);
244 DEBUGP(DL1C, "RACH Req.\n");
245 ul = (struct l1ctl_info_ul *) msgb_put(msg, sizeof(*ul));
246 req = (struct l1ctl_rach_req *) msgb_put(msg, sizeof(*req));
249 return osmo_send_l1(ms, msg);
252 /* Transmit L1CTL_DM_EST_REQ */
253 int tx_ph_dm_est_req(struct osmocom_ms *ms, uint16_t band_arfcn, uint8_t chan_nr)
256 struct l1ctl_info_ul *ul;
257 struct l1ctl_dm_est_req *req;
259 msg = osmo_l1_alloc(L1CTL_DM_EST_REQ);
263 DEBUGP(DL1C, "Tx Dedic.Mode Est Req (arfcn=%u, chan_nr=0x%02x)\n",
264 band_arfcn, chan_nr);
265 ul = (struct l1ctl_info_ul *) msgb_put(msg, sizeof(*ul));
266 ul->chan_nr = chan_nr;
268 ul->tx_power = 0; /* FIXME: initial TX power */
269 req = (struct l1ctl_dm_est_req *) msgb_put(msg, sizeof(*req));
270 req->band_arfcn = band_arfcn;
272 return osmo_send_l1(ms, msg);
275 /* Receive incoming data from L1 using L1CTL format */
276 int l1ctl_recv(struct osmocom_ms *ms, struct msgb *msg)
279 struct l1ctl_hdr *l1h;
280 struct l1ctl_info_dl *dl;
282 if (msgb_l2len(msg) < sizeof(*dl)) {
283 LOGP(DL1C, LOGL_ERROR, "Short Layer2 message: %u\n",
288 l1h = (struct l1ctl_info_dl *) msg->l1h;
290 /* move the l1 header pointer to point _BEHIND_ l1ctl_hdr,
291 as the l1ctl header is of no interest to subsequent code */
292 msg->l1h = l1h->data;
294 switch (l1h->msg_type) {
295 case L1CTL_NEW_CCCH_RESP:
296 rc = rx_l1_ccch_resp(ms, msg);
299 rc = rx_ph_data_ind(ms, msg);
302 rc = rx_l1_reset(ms);
305 fprintf(stderr, "Unknown MSG: %u\n", l1h->msg_type);