Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 1 | /* OpenBSC minimal LAPD implementation */ |
| 2 | |
| 3 | /* (C) 2009 by oystein@homelien.no |
| 4 | * (C) 2009 by Holger Hans Peter Freyther <zecke@selfish.org> |
| 5 | * (C) 2010 by Digium and Matthew Fredrickson <creslin@digium.com> |
| 6 | * (C) 2011 by Harald Welte <laforge@gnumonks.org> |
| 7 | * |
| 8 | * All Rights Reserved |
| 9 | * |
| 10 | * This program is free software; you can redistribute it and/or modify |
| 11 | * it under the terms of the GNU General Public License as published by |
| 12 | * the Free Software Foundation; either version 2 of the License, or |
| 13 | * (at your option) any later version. |
| 14 | * |
| 15 | * This program is distributed in the hope that it will be useful, |
| 16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 18 | * GNU General Public License for more details. |
| 19 | * |
| 20 | * You should have received a copy of the GNU General Public License along |
| 21 | * with this program; if not, write to the Free Software Foundation, Inc., |
| 22 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| 23 | * |
| 24 | */ |
| 25 | |
| 26 | /* TODO: |
| 27 | * detect RR timeout and set SAP state back to SABM_RETRANSMIT |
| 28 | * use of value_string |
| 29 | * further code cleanup (spaghetti) |
| 30 | */ |
| 31 | |
| 32 | #include "internal.h" |
| 33 | |
| 34 | #include <stdio.h> |
| 35 | #include <string.h> |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 36 | #include <errno.h> |
| 37 | |
Pablo Neira Ayuso | 355ce69 | 2011-07-05 14:53:37 +0200 | [diff] [blame] | 38 | #include <osmocom/abis/lapd.h> |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 39 | |
| 40 | #include <osmocom/core/linuxlist.h> |
| 41 | #include <osmocom/core/logging.h> |
Harald Welte | 71d87b2 | 2011-07-18 14:49:56 +0200 | [diff] [blame] | 42 | #include <osmocom/core/talloc.h> |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 43 | #include <osmocom/core/msgb.h> |
| 44 | #include <osmocom/core/timer.h> |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 45 | |
| 46 | #define SABM_INTERVAL 0, 300000 |
| 47 | |
| 48 | typedef enum { |
| 49 | LAPD_TEI_NONE = 0, |
| 50 | LAPD_TEI_ASSIGNED, |
| 51 | LAPD_TEI_ACTIVE, |
| 52 | } lapd_tei_state; |
| 53 | |
| 54 | const char *lapd_tei_states[] = { |
| 55 | "NONE", |
| 56 | "ASSIGNED", |
| 57 | "ACTIVE", |
| 58 | }; |
| 59 | |
| 60 | typedef enum { |
| 61 | LAPD_TYPE_NONE = 0, |
| 62 | |
| 63 | LAPD_TYPE_I, |
| 64 | LAPD_TYPE_S, |
| 65 | LAPD_TYPE_U, |
| 66 | } lapd_msg_type; |
| 67 | |
| 68 | typedef enum { |
| 69 | /* commands/responses */ |
| 70 | LAPD_CMD_NONE = 0, |
| 71 | |
| 72 | LAPD_CMD_I, |
| 73 | LAPD_CMD_RR, |
| 74 | LAPD_CMD_RNR, |
| 75 | LAPD_CMD_REJ, |
| 76 | |
| 77 | LAPD_CMD_SABME, |
| 78 | LAPD_CMD_DM, |
| 79 | LAPD_CMD_UI, |
| 80 | LAPD_CMD_DISC, |
| 81 | LAPD_CMD_UA, |
| 82 | LAPD_CMD_FRMR, |
| 83 | LAPD_CMD_XID, |
| 84 | } lapd_cmd_type; |
| 85 | |
| 86 | const char *lapd_cmd_types[] = { |
| 87 | "NONE", |
| 88 | |
| 89 | "I", |
| 90 | "RR", |
| 91 | "RNR", |
| 92 | "REJ", |
| 93 | |
| 94 | "SABME", |
| 95 | "DM", |
| 96 | "UI", |
| 97 | "DISC", |
| 98 | "UA", |
| 99 | "FRMR", |
| 100 | "XID", |
| 101 | |
| 102 | }; |
| 103 | |
| 104 | enum lapd_sap_state { |
| 105 | SAP_STATE_INACTIVE, |
| 106 | SAP_STATE_SABM_RETRANS, |
| 107 | SAP_STATE_ACTIVE, |
| 108 | }; |
| 109 | |
| 110 | const char *lapd_sap_states[] = { |
| 111 | "INACTIVE", |
| 112 | "SABM_RETRANS", |
| 113 | "ACTIVE", |
| 114 | }; |
| 115 | |
| 116 | const char *lapd_msg_types = "?ISU"; |
| 117 | |
| 118 | /* structure representing an allocated TEI within a LAPD instance */ |
| 119 | struct lapd_tei { |
| 120 | struct llist_head list; |
| 121 | struct lapd_instance *li; |
| 122 | uint8_t tei; |
| 123 | lapd_tei_state state; |
| 124 | |
| 125 | struct llist_head sap_list; |
| 126 | }; |
| 127 | |
| 128 | /* Structure representing a SAP within a TEI. We use this for TE-mode to |
| 129 | * re-transmit SABM */ |
| 130 | struct lapd_sap { |
| 131 | struct llist_head list; |
| 132 | struct lapd_tei *tei; |
| 133 | uint8_t sapi; |
| 134 | enum lapd_sap_state state; |
| 135 | |
| 136 | /* A valid N(R) value is one that is in the range V(A) ≤ N(R) ≤ V(S). */ |
| 137 | int vs; /* next to be transmitted */ |
| 138 | int va; /* last acked by peer */ |
| 139 | int vr; /* next expected to be received */ |
| 140 | |
| 141 | struct osmo_timer_list sabme_timer; /* timer to re-transmit SABM message */ |
| 142 | }; |
| 143 | |
| 144 | /* 3.5.2.2 Send state variable V(S) |
| 145 | * Each point-to-point data link connection endpoint shall have an associated V(S) when using I frame |
| 146 | * commands. V(S) denotes the sequence number of the next I frame to be transmitted. The V(S) can |
| 147 | * take on the value 0 through n minus 1. The value of V(S) shall be incremented by 1 with each |
| 148 | * successive I frame transmission, and shall not exceed V(A) by more than the maximum number of |
| 149 | * outstanding I frames k. The value of k may be in the range of 1 ≤ k ≤ 127. |
| 150 | * |
| 151 | * 3.5.2.3 Acknowledge state variable V(A) |
| 152 | * Each point-to-point data link connection endpoint shall have an associated V(A) when using I frame |
| 153 | * commands and supervisory frame commands/responses. V(A) identifies the last I frame that has been |
| 154 | * acknowledged by its peer [V(A) − 1 equals the N(S) of the last acknowledged I frame]. V(A) can |
| 155 | * take on the value 0 through n minus 1. The value of V(A) shall be updated by the valid N(R) values |
| 156 | * received from its peer (see 3.5.2.6). A valid N(R) value is one that is in the range V(A) ≤ N(R) ≤ |
| 157 | * V(S). |
| 158 | * |
| 159 | * 3.5.2.5 Receive state variable V(R) |
| 160 | * Each point-to-point data link connection endpoint shall have an associated V(R) when using I frame |
| 161 | * commands and supervisory frame commands/responses. V(R) denotes the sequence number of the |
| 162 | * next in-sequence I frame expected to be received. V(R) can take on the value 0 through n minus 1. |
| 163 | * The value of V(R) shall be incremented by one with the receipt of an error-free, in-sequence I frame |
| 164 | * whose N(S) equals V(R). |
| 165 | */ |
| 166 | #define LAPD_NS(sap) (sap->vs) |
| 167 | #define LAPD_NR(sap) (sap->vr) |
| 168 | |
| 169 | /* 3.5.2.4 Send sequence number N(S) |
| 170 | * Only I frames contain N(S), the send sequence number of transmitted I frames. At the time that an in- |
| 171 | * sequence I frame is designated for transmission, the value of N(S) is set equal to V(S). |
| 172 | * |
| 173 | * 3.5.2.6 Receive sequence number N(R) |
| 174 | * All I frames and supervisory frames contain N(R), the expected send sequence number of the next |
| 175 | * received I frame. At the time that a frame of the above types is designated for transmission, the value |
| 176 | * of N(R) is set equal to V(R). N(R) indicates that the data link layer entity transmitting the N(R) has |
| 177 | * correctly received all I frames numbered up to and including N(R) − 1. |
| 178 | */ |
| 179 | |
| 180 | /* Resolve TEI structure from given numeric TEI */ |
| 181 | static struct lapd_tei *teip_from_tei(struct lapd_instance *li, uint8_t tei) |
| 182 | { |
| 183 | struct lapd_tei *lt; |
| 184 | |
| 185 | llist_for_each_entry(lt, &li->tei_list, list) { |
| 186 | if (lt->tei == tei) |
| 187 | return lt; |
| 188 | } |
| 189 | return NULL; |
| 190 | }; |
| 191 | |
| 192 | static void lapd_tei_set_state(struct lapd_tei *teip, int newstate) |
| 193 | { |
Harald Welte | 4ca16c7 | 2011-08-16 14:01:49 +0200 | [diff] [blame] | 194 | LOGP(DLMI, LOGL_INFO, "LAPD state change on TEI %d: %s -> %s\n", teip->tei, |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 195 | lapd_tei_states[teip->state], lapd_tei_states[newstate]); |
| 196 | teip->state = newstate; |
| 197 | }; |
| 198 | |
| 199 | /* Allocate a new TEI */ |
| 200 | struct lapd_tei *lapd_tei_alloc(struct lapd_instance *li, uint8_t tei) |
| 201 | { |
| 202 | struct lapd_tei *teip; |
| 203 | |
| 204 | teip = talloc_zero(li, struct lapd_tei); |
| 205 | if (!teip) |
| 206 | return NULL; |
| 207 | |
| 208 | teip->li = li; |
| 209 | teip->tei = tei; |
| 210 | llist_add(&teip->list, &li->tei_list); |
| 211 | INIT_LLIST_HEAD(&teip->sap_list); |
| 212 | |
| 213 | lapd_tei_set_state(teip, LAPD_TEI_ASSIGNED); |
| 214 | |
| 215 | return teip; |
| 216 | } |
| 217 | |
| 218 | /* Find a SAP within a given TEI */ |
| 219 | static struct lapd_sap *lapd_sap_find(struct lapd_tei *teip, uint8_t sapi) |
| 220 | { |
| 221 | struct lapd_sap *sap; |
| 222 | |
| 223 | llist_for_each_entry(sap, &teip->sap_list, list) { |
| 224 | if (sap->sapi == sapi) |
| 225 | return sap; |
| 226 | } |
| 227 | |
| 228 | return NULL; |
| 229 | } |
| 230 | |
| 231 | static void sabme_timer_cb(void *_sap); |
| 232 | |
| 233 | /* Allocate a new SAP within a given TEI */ |
| 234 | static struct lapd_sap *lapd_sap_alloc(struct lapd_tei *teip, uint8_t sapi) |
| 235 | { |
| 236 | struct lapd_sap *sap = talloc_zero(teip, struct lapd_sap); |
| 237 | |
Harald Welte | 4ca16c7 | 2011-08-16 14:01:49 +0200 | [diff] [blame] | 238 | LOGP(DLMI, LOGL_INFO, "LAPD Allocating SAP for SAPI=%u / TEI=%u\n", |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 239 | sapi, teip->tei); |
| 240 | |
| 241 | sap->sapi = sapi; |
| 242 | sap->tei = teip; |
| 243 | sap->sabme_timer.cb = &sabme_timer_cb; |
| 244 | sap->sabme_timer.data = sap; |
| 245 | |
| 246 | llist_add(&sap->list, &teip->sap_list); |
| 247 | |
| 248 | return sap; |
| 249 | } |
| 250 | |
| 251 | static void lapd_sap_set_state(struct lapd_tei *teip, uint8_t sapi, |
| 252 | enum lapd_sap_state newstate) |
| 253 | { |
| 254 | struct lapd_sap *sap = lapd_sap_find(teip, sapi); |
| 255 | if (!sap) |
| 256 | return; |
| 257 | |
Harald Welte | 4ca16c7 | 2011-08-16 14:01:49 +0200 | [diff] [blame] | 258 | LOGP(DLMI, LOGL_INFO, "LAPD state change on TEI %u / SAPI %u: " |
| 259 | "%s -> %s\n", teip->tei, sapi, |
| 260 | lapd_sap_states[sap->state], lapd_sap_states[newstate]); |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 261 | switch (sap->state) { |
| 262 | case SAP_STATE_SABM_RETRANS: |
| 263 | if (newstate != SAP_STATE_SABM_RETRANS) |
| 264 | osmo_timer_del(&sap->sabme_timer); |
| 265 | break; |
| 266 | default: |
| 267 | if (newstate == SAP_STATE_SABM_RETRANS) |
| 268 | osmo_timer_schedule(&sap->sabme_timer, SABM_INTERVAL); |
| 269 | break; |
| 270 | } |
| 271 | |
| 272 | sap->state = newstate; |
| 273 | }; |
| 274 | |
| 275 | /* Input function into TEI manager */ |
| 276 | static void lapd_tei_receive(struct lapd_instance *li, uint8_t *data, int len) |
| 277 | { |
| 278 | uint8_t entity = data[0]; |
| 279 | uint8_t ref = data[1]; |
| 280 | uint8_t mt = data[3]; |
| 281 | uint8_t action = data[4] >> 1; |
| 282 | uint8_t e = data[4] & 1; |
| 283 | uint8_t resp[8]; |
| 284 | struct lapd_tei *teip; |
| 285 | |
Harald Welte | 4ca16c7 | 2011-08-16 14:01:49 +0200 | [diff] [blame] | 286 | DEBUGP(DLMI, "LAPD TEIMGR: entity %x, ref %x, mt %x, action %x, e %x\n", |
| 287 | entity, ref, mt, action, e); |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 288 | |
| 289 | switch (mt) { |
| 290 | case 0x01: /* IDENTITY REQUEST */ |
Harald Welte | 4ca16c7 | 2011-08-16 14:01:49 +0200 | [diff] [blame] | 291 | DEBUGP(DLMI, "LAPD TEIMGR: identity request for TEI %u\n", action); |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 292 | |
| 293 | teip = teip_from_tei(li, action); |
| 294 | if (!teip) { |
Harald Welte | cc2241b | 2011-07-19 16:06:06 +0200 | [diff] [blame] | 295 | LOGP(DLMI, LOGL_INFO, "TEI MGR: New TEI %u\n", action); |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 296 | teip = lapd_tei_alloc(li, action); |
| 297 | } |
| 298 | |
| 299 | /* Send ACCEPT */ |
| 300 | memmove(resp, "\xfe\xff\x03\x0f\x00\x00\x02\x00", 8); |
| 301 | resp[7] = (action << 1) | 1; |
| 302 | li->transmit_cb(resp, 8, li->cbdata); |
| 303 | |
| 304 | if (teip->state == LAPD_TEI_NONE) |
| 305 | lapd_tei_set_state(teip, LAPD_TEI_ASSIGNED); |
| 306 | break; |
| 307 | default: |
Harald Welte | 4ca16c7 | 2011-08-16 14:01:49 +0200 | [diff] [blame] | 308 | LOGP(DLMI, LOGL_NOTICE, "LAPD TEIMGR: unknown mt %x action %x\n", |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 309 | mt, action); |
| 310 | break; |
| 311 | }; |
| 312 | }; |
| 313 | |
| 314 | /* General input function for any data received for this LAPD instance */ |
Pablo Neira Ayuso | 31fe5f2 | 2011-08-09 23:15:38 +0200 | [diff] [blame^] | 315 | uint8_t * |
| 316 | lapd_receive(struct lapd_instance *li, uint8_t * data, unsigned int len, |
| 317 | int *ilen, lapd_mph_type *prim, int *error) |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 318 | { |
| 319 | uint8_t sapi, cr, tei, command; |
| 320 | int pf, ns, nr; |
| 321 | uint8_t *contents; |
| 322 | struct lapd_tei *teip; |
| 323 | struct lapd_sap *sap; |
| 324 | |
| 325 | uint8_t resp[8]; |
| 326 | int l = 0; |
| 327 | |
| 328 | *ilen = 0; |
| 329 | *prim = 0; |
| 330 | |
| 331 | if (len < 2) { |
Harald Welte | 4ca16c7 | 2011-08-16 14:01:49 +0200 | [diff] [blame] | 332 | LOGP(DLMI, LOGL_ERROR, "LAPD receive len %d < 2, ignoring\n", len); |
Pablo Neira Ayuso | 31fe5f2 | 2011-08-09 23:15:38 +0200 | [diff] [blame^] | 333 | *error = LAPD_ERR_BAD_LEN; |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 334 | return NULL; |
| 335 | }; |
| 336 | |
| 337 | if ((data[0] & 1) != 0 || (data[1] & 1) != 1) { |
Harald Welte | 4ca16c7 | 2011-08-16 14:01:49 +0200 | [diff] [blame] | 338 | LOGP(DLMI, LOGL_ERROR, "LAPD address field %x/%x not well formed\n", |
| 339 | data[0], data[1]); |
Pablo Neira Ayuso | 31fe5f2 | 2011-08-09 23:15:38 +0200 | [diff] [blame^] | 340 | *error = LAPD_ERR_BAD_ADDR; |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 341 | return NULL; |
| 342 | }; |
| 343 | |
| 344 | sapi = data[0] >> 2; |
| 345 | cr = (data[0] >> 1) & 1; |
| 346 | tei = data[1] >> 1; |
| 347 | command = li->network_side ^ cr; |
Harald Welte | cc2241b | 2011-07-19 16:06:06 +0200 | [diff] [blame] | 348 | //DEBUGP(DLMI, " address sapi %x tei %d cmd %d cr %d\n", sapi, tei, command, cr); |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 349 | |
| 350 | if (len < 3) { |
Harald Welte | 4ca16c7 | 2011-08-16 14:01:49 +0200 | [diff] [blame] | 351 | LOGP(DLMI, LOGL_ERROR, "LAPD receive len %d < 3, ignoring\n", len); |
Pablo Neira Ayuso | 31fe5f2 | 2011-08-09 23:15:38 +0200 | [diff] [blame^] | 352 | *error = LAPD_ERR_BAD_LEN; |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 353 | return NULL; |
| 354 | }; |
| 355 | |
| 356 | lapd_msg_type typ = 0; |
| 357 | lapd_cmd_type cmd = 0; |
| 358 | pf = -1; |
| 359 | ns = -1; |
| 360 | nr = -1; |
| 361 | if ((data[2] & 1) == 0) { |
| 362 | typ = LAPD_TYPE_I; |
Harald Welte | 1ef2457 | 2011-08-16 13:51:07 +0200 | [diff] [blame] | 363 | if (len < 4) { |
Harald Welte | 4ca16c7 | 2011-08-16 14:01:49 +0200 | [diff] [blame] | 364 | LOGP(DLMI, LOGL_ERROR, "LAPD I frame, len %d < 4\n", len); |
Pablo Neira Ayuso | 31fe5f2 | 2011-08-09 23:15:38 +0200 | [diff] [blame^] | 365 | *error = LAPD_ERR_BAD_LEN; |
Harald Welte | 1ef2457 | 2011-08-16 13:51:07 +0200 | [diff] [blame] | 366 | return NULL; |
| 367 | } |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 368 | ns = data[2] >> 1; |
| 369 | nr = data[3] >> 1; |
| 370 | pf = data[3] & 1; |
| 371 | cmd = LAPD_CMD_I; |
| 372 | } else if ((data[2] & 3) == 1) { |
| 373 | typ = LAPD_TYPE_S; |
Harald Welte | 1ef2457 | 2011-08-16 13:51:07 +0200 | [diff] [blame] | 374 | if (len < 4) { |
Harald Welte | 4ca16c7 | 2011-08-16 14:01:49 +0200 | [diff] [blame] | 375 | LOGP(DLMI, LOGL_ERROR, "LAPD S frame, len %d < 4\n", len); |
Pablo Neira Ayuso | 31fe5f2 | 2011-08-09 23:15:38 +0200 | [diff] [blame^] | 376 | *error = LAPD_ERR_BAD_LEN; |
Harald Welte | 1ef2457 | 2011-08-16 13:51:07 +0200 | [diff] [blame] | 377 | return NULL; |
| 378 | } |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 379 | nr = data[3] >> 1; |
| 380 | pf = data[3] & 1; |
| 381 | switch (data[2]) { |
| 382 | case 0x1: |
| 383 | cmd = LAPD_CMD_RR; |
| 384 | break; |
| 385 | case 0x5: |
| 386 | cmd = LAPD_CMD_RNR; |
| 387 | break; |
| 388 | case 0x9: |
| 389 | cmd = LAPD_CMD_REJ; |
| 390 | break; |
| 391 | default: |
Harald Welte | 4ca16c7 | 2011-08-16 14:01:49 +0200 | [diff] [blame] | 392 | LOGP(DLMI, LOGL_ERROR, "LAPD unknown S cmd %x\n", data[2]); |
Pablo Neira Ayuso | 31fe5f2 | 2011-08-09 23:15:38 +0200 | [diff] [blame^] | 393 | *error = LAPD_ERR_UNKNOWN_S_CMD; |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 394 | return NULL; |
| 395 | }; |
| 396 | } else if ((data[2] & 3) == 3) { |
| 397 | typ = LAPD_TYPE_U; |
| 398 | pf = (data[2] >> 4) & 1; |
| 399 | int val = data[2] & ~(1 << 4); |
| 400 | switch (val) { |
| 401 | case 0x6f: |
| 402 | cmd = LAPD_CMD_SABME; |
| 403 | break; |
| 404 | case 0x0f: |
| 405 | cmd = LAPD_CMD_DM; |
| 406 | break; |
| 407 | case 0x03: |
| 408 | cmd = LAPD_CMD_UI; |
| 409 | break; |
| 410 | case 0x43: |
| 411 | cmd = LAPD_CMD_DISC; |
| 412 | break; |
| 413 | case 0x63: |
| 414 | cmd = LAPD_CMD_UA; |
| 415 | break; |
| 416 | case 0x87: |
| 417 | cmd = LAPD_CMD_FRMR; |
| 418 | break; |
| 419 | case 0xaf: |
| 420 | cmd = LAPD_CMD_XID; |
| 421 | break; |
| 422 | |
| 423 | default: |
Harald Welte | 4ca16c7 | 2011-08-16 14:01:49 +0200 | [diff] [blame] | 424 | LOGP(DLMI, LOGL_ERROR, "LAPD unknown U cmd %x " |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 425 | "(pf %x data %x)\n", val, pf, data[2]); |
Pablo Neira Ayuso | 31fe5f2 | 2011-08-09 23:15:38 +0200 | [diff] [blame^] | 426 | *error = LAPD_ERR_UNKNOWN_U_CMD; |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 427 | return NULL; |
| 428 | }; |
| 429 | }; |
| 430 | |
| 431 | contents = &data[4]; |
| 432 | if (typ == LAPD_TYPE_U) |
| 433 | contents--; |
| 434 | *ilen = len - (contents - data); |
| 435 | |
| 436 | if (tei == 127) |
| 437 | lapd_tei_receive(li, contents, *ilen); |
| 438 | |
| 439 | teip = teip_from_tei(li, tei); |
| 440 | if (!teip) { |
Harald Welte | 4ca16c7 | 2011-08-16 14:01:49 +0200 | [diff] [blame] | 441 | LOGP(DLMI, LOGL_NOTICE, "LAPD Unknown TEI %u\n", tei); |
Pablo Neira Ayuso | 31fe5f2 | 2011-08-09 23:15:38 +0200 | [diff] [blame^] | 442 | *error = LAPD_ERR_UNKNOWN_TEI; |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 443 | return NULL; |
| 444 | } |
| 445 | |
| 446 | sap = lapd_sap_find(teip, sapi); |
| 447 | if (!sap) { |
Harald Welte | 4ca16c7 | 2011-08-16 14:01:49 +0200 | [diff] [blame] | 448 | LOGP(DLMI, LOGL_INFO, "LAPD No SAP for TEI=%u / SAPI=%u, " |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 449 | "allocating\n", tei, sapi); |
| 450 | sap = lapd_sap_alloc(teip, sapi); |
| 451 | } |
| 452 | |
Harald Welte | cc2241b | 2011-07-19 16:06:06 +0200 | [diff] [blame] | 453 | DEBUGP(DLMI, "<- %c %s sapi %x tei %3d cmd %x pf %x ns %3d nr %3d " |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 454 | "ilen %d teip %p vs %d va %d vr %d len %d\n", |
| 455 | lapd_msg_types[typ], lapd_cmd_types[cmd], sapi, tei, command, pf, |
| 456 | ns, nr, *ilen, teip, sap->vs, sap->va, sap->vr, len); |
| 457 | |
| 458 | switch (cmd) { |
| 459 | case LAPD_CMD_I: |
| 460 | if (ns != sap->vr) { |
Harald Welte | 4ca16c7 | 2011-08-16 14:01:49 +0200 | [diff] [blame] | 461 | DEBUGP(DLMI, "LAPD ns %d != vr %d\n", ns, sap->vr); |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 462 | if (ns == ((sap->vr - 1) & 0x7f)) { |
Harald Welte | 4ca16c7 | 2011-08-16 14:01:49 +0200 | [diff] [blame] | 463 | LOGP(DLMI, LOGL_NOTICE, "LAPD double frame, " |
| 464 | "ignoring\n"); |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 465 | cmd = 0; // ignore |
| 466 | } else { |
Harald Welte | 4ca16c7 | 2011-08-16 14:01:49 +0200 | [diff] [blame] | 467 | LOGP(DLMI, LOGL_ERROR, "LAPD Out of order " |
Harald Welte | 1ef2457 | 2011-08-16 13:51:07 +0200 | [diff] [blame] | 468 | "ns %d != vr %d, ignoring\n", ns, sap->vr); |
| 469 | return NULL; |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 470 | }; |
| 471 | } else { |
| 472 | //printf("IN SEQUENCE\n"); |
| 473 | sap->vr = (ns + 1) & 0x7f; // FIXME: hack! |
| 474 | }; |
| 475 | |
| 476 | break; |
| 477 | case LAPD_CMD_UI: |
| 478 | break; |
| 479 | case LAPD_CMD_SABME: |
| 480 | sap->vs = 0; |
| 481 | sap->vr = 0; |
| 482 | sap->va = 0; |
| 483 | |
| 484 | // ua |
| 485 | resp[l++] = data[0]; |
| 486 | resp[l++] = (tei << 1) | 1; |
| 487 | resp[l++] = 0x73; |
| 488 | li->transmit_cb(resp, l, li->cbdata); |
| 489 | if (teip->state != LAPD_TEI_ACTIVE) { |
| 490 | if (teip->state == LAPD_TEI_ASSIGNED) { |
| 491 | lapd_tei_set_state(teip, |
| 492 | LAPD_TEI_ACTIVE); |
| 493 | //printf("ASSIGNED and ACTIVE\n"); |
| 494 | } else { |
| 495 | #if 0 |
Harald Welte | cc2241b | 2011-07-19 16:06:06 +0200 | [diff] [blame] | 496 | DEBUGP(DLMI, "rr in strange state, send rej\n"); |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 497 | |
| 498 | // rej |
| 499 | resp[l++] = (sap-> sapi << 2) | (li->network_side ? 0 : 2); |
| 500 | resp[l++] = (tei << 1) | 1; |
| 501 | resp[l++] = 0x09; //rej |
| 502 | resp[l++] = ((sap->vr + 1) << 1) | 0; |
| 503 | li->transmit_cb(resp, l, li->cbdata); |
| 504 | pf = 0; // dont reply |
| 505 | #endif |
| 506 | }; |
| 507 | }; |
| 508 | |
| 509 | *prim = LAPD_MPH_ACTIVATE_IND; |
| 510 | break; |
| 511 | case LAPD_CMD_UA: |
| 512 | sap->vs = 0; |
| 513 | sap->vr = 0; |
| 514 | sap->va = 0; |
| 515 | lapd_tei_set_state(teip, LAPD_TEI_ACTIVE); |
| 516 | lapd_sap_set_state(teip, sapi, SAP_STATE_ACTIVE); |
| 517 | *prim = LAPD_MPH_ACTIVATE_IND; |
| 518 | break; |
| 519 | case LAPD_CMD_RR: |
| 520 | sap->va = (nr & 0x7f); |
| 521 | #if 0 |
| 522 | if (teip->state != LAPD_TEI_ACTIVE) { |
| 523 | if (teip->state == LAPD_TEI_ASSIGNED) { |
| 524 | lapd_tei_set_state(teip, LAPD_TEI_ACTIVE); |
| 525 | *prim = LAPD_MPH_ACTIVATE_IND; |
| 526 | //printf("ASSIGNED and ACTIVE\n"); |
| 527 | } else { |
| 528 | #if 0 |
Harald Welte | cc2241b | 2011-07-19 16:06:06 +0200 | [diff] [blame] | 529 | DEBUGP(DLMI, "rr in strange " "state, send rej\n"); |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 530 | |
| 531 | // rej |
| 532 | resp[l++] = (sap-> sapi << 2) | (li->network_side ? 0 : 2); |
| 533 | resp[l++] = (tei << 1) | 1; |
| 534 | resp[l++] = 0x09; //rej |
| 535 | resp[l++] = |
| 536 | ((sap->vr + 1) << 1) | 0; |
| 537 | li->transmit_cb(resp, l, li->cbdata); |
| 538 | pf = 0; // dont reply |
| 539 | #endif |
| 540 | }; |
| 541 | }; |
| 542 | #endif |
| 543 | if (pf) { |
| 544 | // interrogating us, send rr |
| 545 | resp[l++] = data[0]; |
| 546 | resp[l++] = (tei << 1) | 1; |
| 547 | resp[l++] = 0x01; // rr |
| 548 | resp[l++] = (LAPD_NR(sap) << 1) | (data[3] & 1); // pf bit from req |
| 549 | |
| 550 | li->transmit_cb(resp, l, li->cbdata); |
| 551 | |
| 552 | }; |
| 553 | break; |
| 554 | case LAPD_CMD_FRMR: |
| 555 | // frame reject |
| 556 | #if 0 |
| 557 | if (teip->state == LAPD_TEI_ACTIVE) |
| 558 | *prim = LAPD_MPH_DEACTIVATE_IND; |
| 559 | lapd_tei_set_state(teip, LAPD_TEI_ASSIGNED); |
| 560 | #endif |
Harald Welte | cc2241b | 2011-07-19 16:06:06 +0200 | [diff] [blame] | 561 | LOGP(DLMI, LOGL_NOTICE, "frame reject, ignoring\n"); |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 562 | break; |
| 563 | case LAPD_CMD_DISC: |
| 564 | // disconnect |
| 565 | resp[l++] = data[0]; |
| 566 | resp[l++] = (tei << 1) | 1; |
| 567 | resp[l++] = 0x73; |
| 568 | li->transmit_cb(resp, l, li->cbdata); |
| 569 | lapd_tei_set_state(teip, LAPD_TEI_NONE); |
| 570 | break; |
| 571 | default: |
Harald Welte | cc2241b | 2011-07-19 16:06:06 +0200 | [diff] [blame] | 572 | LOGP(DLMI, LOGL_NOTICE, "unknown cmd for tei %d (cmd %x)\n", |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 573 | tei, cmd); |
| 574 | break; |
| 575 | } |
| 576 | |
| 577 | if (typ == LAPD_TYPE_I) { |
| 578 | /* send rr |
| 579 | * Thu Jan 22 19:17:13 2009 <4000> sangoma.c:340 read (62/25) 4: fa 33 01 0a |
| 580 | * lapd <- S RR sapi 3e tei 25 cmd 0 pf 0 ns -1 nr 5 ilen 0 teip 0x613800 vs 7 va 5 vr 2 len 4 |
| 581 | */ |
| 582 | |
| 583 | /* interrogating us, send rr */ |
Harald Welte | 4ca16c7 | 2011-08-16 14:01:49 +0200 | [diff] [blame] | 584 | DEBUGP(DLMI, "LAPD Sending RR response\n"); |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 585 | resp[l++] = data[0]; |
| 586 | resp[l++] = (tei << 1) | 1; |
| 587 | resp[l++] = 0x01; // rr |
| 588 | resp[l++] = (LAPD_NR(sap) << 1) | (data[3] & 1); // pf bit from req |
| 589 | |
| 590 | li->transmit_cb(resp, l, li->cbdata); |
| 591 | |
| 592 | if (cmd != 0) { |
| 593 | *prim = LAPD_DL_DATA_IND; |
| 594 | return contents; |
| 595 | } |
| 596 | } else if (tei != 127 && typ == LAPD_TYPE_U && cmd == LAPD_CMD_UI) { |
| 597 | *prim = LAPD_DL_UNITDATA_IND; |
| 598 | return contents; |
| 599 | } |
| 600 | |
Pablo Neira Ayuso | 31fe5f2 | 2011-08-09 23:15:38 +0200 | [diff] [blame^] | 601 | *error = LAPD_ERR_BAD_CMD; |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 602 | return NULL; |
| 603 | }; |
| 604 | |
| 605 | /* low-level function to send a single SABM message */ |
| 606 | static int lapd_send_sabm(struct lapd_instance *li, uint8_t tei, uint8_t sapi) |
| 607 | { |
| 608 | struct msgb *msg = msgb_alloc_headroom(1024, 128, "LAPD SABM"); |
| 609 | if (!msg) |
| 610 | return -ENOMEM; |
| 611 | |
Harald Welte | 4ca16c7 | 2011-08-16 14:01:49 +0200 | [diff] [blame] | 612 | LOGP(DLMI, LOGL_INFO, "LAPD Sending SABM for TEI=%u, SAPI=%u\n", tei, sapi); |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 613 | |
| 614 | msgb_put_u8(msg, (sapi << 2) | (li->network_side ? 2 : 0)); |
| 615 | msgb_put_u8(msg, (tei << 1) | 1); |
| 616 | msgb_put_u8(msg, 0x7F); |
| 617 | |
| 618 | li->transmit_cb(msg->data, msg->len, li->cbdata); |
| 619 | |
| 620 | msgb_free(msg); |
| 621 | |
| 622 | return 0; |
| 623 | } |
| 624 | |
| 625 | /* timer call-back function for SABM re-transmission */ |
| 626 | static void sabme_timer_cb(void *_sap) |
| 627 | { |
| 628 | struct lapd_sap *sap = _sap; |
| 629 | |
| 630 | lapd_send_sabm(sap->tei->li, sap->tei->tei, sap->sapi); |
| 631 | |
| 632 | if (sap->state == SAP_STATE_SABM_RETRANS) |
| 633 | osmo_timer_schedule(&sap->sabme_timer, SABM_INTERVAL); |
| 634 | } |
| 635 | |
| 636 | /* Start a (user-side) SAP for the specified TEI/SAPI on the LAPD instance */ |
| 637 | int lapd_sap_start(struct lapd_instance *li, uint8_t tei, uint8_t sapi) |
| 638 | { |
| 639 | struct lapd_sap *sap; |
| 640 | struct lapd_tei *teip; |
| 641 | |
| 642 | teip = teip_from_tei(li, tei); |
| 643 | if (!teip) |
| 644 | teip = lapd_tei_alloc(li, tei); |
| 645 | |
| 646 | sap = lapd_sap_find(teip, sapi); |
| 647 | if (sap) |
| 648 | return -EEXIST; |
| 649 | |
| 650 | sap = lapd_sap_alloc(teip, sapi); |
| 651 | |
| 652 | lapd_sap_set_state(teip, sapi, SAP_STATE_SABM_RETRANS); |
| 653 | |
| 654 | return 0; |
| 655 | } |
| 656 | |
| 657 | /* Stop a (user-side) SAP for the specified TEI/SAPI on the LAPD instance */ |
| 658 | int lapd_sap_stop(struct lapd_instance *li, uint8_t tei, uint8_t sapi) |
| 659 | { |
| 660 | struct lapd_tei *teip; |
| 661 | struct lapd_sap *sap; |
| 662 | |
| 663 | teip = teip_from_tei(li, tei); |
| 664 | if (!teip) |
| 665 | return -ENODEV; |
| 666 | |
| 667 | sap = lapd_sap_find(teip, sapi); |
| 668 | if (!sap) |
| 669 | return -ENODEV; |
| 670 | |
| 671 | lapd_sap_set_state(teip, sapi, SAP_STATE_INACTIVE); |
| 672 | |
| 673 | llist_del(&sap->list); |
| 674 | talloc_free(sap); |
| 675 | |
| 676 | return 0; |
| 677 | } |
| 678 | |
| 679 | /* Transmit Data (I-Frame) on the given LAPD Instance / TEI / SAPI */ |
| 680 | void lapd_transmit(struct lapd_instance *li, uint8_t tei, uint8_t sapi, |
| 681 | uint8_t *data, unsigned int len) |
| 682 | { |
| 683 | struct lapd_tei *teip = teip_from_tei(li, tei); |
| 684 | struct lapd_sap *sap; |
| 685 | |
| 686 | if (!teip) { |
Harald Welte | 4ca16c7 | 2011-08-16 14:01:49 +0200 | [diff] [blame] | 687 | LOGP(DLMI, LOGL_ERROR, "LAPD Cannot transmit on " |
| 688 | "non-existing TEI %u\n", tei); |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 689 | return; |
| 690 | } |
| 691 | |
| 692 | sap = lapd_sap_find(teip, sapi); |
| 693 | if (!sap) { |
Harald Welte | 4ca16c7 | 2011-08-16 14:01:49 +0200 | [diff] [blame] | 694 | LOGP(DLMI, LOGL_INFO, "LAPD Tx on unknown SAPI=%u " |
| 695 | "in TEI=%u, allocating\n", sapi, tei); |
Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 696 | sap = lapd_sap_alloc(teip, sapi); |
| 697 | } |
| 698 | |
| 699 | /* prepend stuff */ |
| 700 | uint8_t buf[10000]; |
| 701 | memset(buf, 0, sizeof(buf)); |
| 702 | memmove(buf + 4, data, len); |
| 703 | len += 4; |
| 704 | |
| 705 | buf[0] = (sapi << 2) | (li->network_side ? 2 : 0); |
| 706 | buf[1] = (tei << 1) | 1; |
| 707 | buf[2] = (LAPD_NS(sap) << 1); |
| 708 | buf[3] = (LAPD_NR(sap) << 1) | 0; |
| 709 | |
| 710 | sap->vs = (sap->vs + 1) & 0x7f; |
| 711 | |
| 712 | li->transmit_cb(buf, len, li->cbdata); |
| 713 | }; |
| 714 | |
| 715 | /* Allocate a new LAPD instance */ |
| 716 | struct lapd_instance *lapd_instance_alloc(int network_side, |
| 717 | void (*tx_cb)(uint8_t *data, int len, |
| 718 | void *cbdata), void *cbdata) |
| 719 | { |
| 720 | struct lapd_instance *li; |
| 721 | |
| 722 | li = talloc_zero(NULL, struct lapd_instance); |
| 723 | if (!li) |
| 724 | return NULL; |
| 725 | |
| 726 | li->transmit_cb = tx_cb; |
| 727 | li->cbdata = cbdata; |
| 728 | li->network_side = network_side; |
| 729 | INIT_LLIST_HEAD(&li->tei_list); |
| 730 | |
| 731 | return li; |
| 732 | } |