Holger Hans Peter Freyther | bc1e52c | 2013-08-22 08:44:38 +0200 | [diff] [blame] | 1 | /* (C) 2009-2010 by Harald Welte <laforge@gnumonks.org> |
| 2 | * |
| 3 | * All Rights Reserved |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify |
| 6 | * it under the terms of the GNU Affero General Public License as published by |
| 7 | * the Free Software Foundation; either version 3 of the License, or |
| 8 | * (at your option) any later version. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU Affero General Public License for more details. |
| 14 | * |
| 15 | * You should have received a copy of the GNU Affero General Public License |
| 16 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 17 | * |
| 18 | */ |
| 19 | #include "openbsc_clone.h" |
| 20 | |
| 21 | #include <gprs_debug.h> |
| 22 | |
| 23 | #include <osmocom/core/utils.h> |
Holger Hans Peter Freyther | 9d93838 | 2013-07-31 21:59:29 +0200 | [diff] [blame] | 24 | #include <osmocom/gsm/tlv.h> |
Holger Hans Peter Freyther | bc1e52c | 2013-08-22 08:44:38 +0200 | [diff] [blame] | 25 | |
| 26 | #include <errno.h> |
| 27 | |
| 28 | /* Section 6.4 Commands and Responses */ |
| 29 | enum gprs_llc_u_cmd { |
| 30 | GPRS_LLC_U_DM_RESP = 0x01, |
| 31 | GPRS_LLC_U_DISC_CMD = 0x04, |
| 32 | GPRS_LLC_U_UA_RESP = 0x06, |
| 33 | GPRS_LLC_U_SABM_CMD = 0x07, |
| 34 | GPRS_LLC_U_FRMR_RESP = 0x08, |
| 35 | GPRS_LLC_U_XID = 0x0b, |
| 36 | GPRS_LLC_U_NULL_CMD = 0x00, |
| 37 | }; |
| 38 | |
| 39 | #define LLC_ALLOC_SIZE 16384 |
| 40 | #define UI_HDR_LEN 3 |
| 41 | #define N202 4 |
| 42 | #define CRC24_LENGTH 3 |
| 43 | |
| 44 | static const struct value_string llc_cmd_strs[] = { |
| 45 | { GPRS_LLC_NULL, "NULL" }, |
| 46 | { GPRS_LLC_RR, "RR" }, |
| 47 | { GPRS_LLC_ACK, "ACK" }, |
| 48 | { GPRS_LLC_RNR, "RNR" }, |
| 49 | { GPRS_LLC_SACK, "SACK" }, |
| 50 | { GPRS_LLC_DM, "DM" }, |
| 51 | { GPRS_LLC_DISC, "DISC" }, |
| 52 | { GPRS_LLC_UA, "UA" }, |
| 53 | { GPRS_LLC_SABM, "SABM" }, |
| 54 | { GPRS_LLC_FRMR, "FRMR" }, |
| 55 | { GPRS_LLC_XID, "XID" }, |
| 56 | { GPRS_LLC_UI, "UI" }, |
| 57 | { 0, NULL } |
| 58 | }; |
| 59 | |
| 60 | int gprs_llc_hdr_parse(struct gprs_llc_hdr_parsed *ghp, |
| 61 | const uint8_t *llc_hdr, int len) |
| 62 | { |
| 63 | const uint8_t *ctrl = llc_hdr+1; |
| 64 | |
| 65 | if (len <= CRC24_LENGTH) |
| 66 | return -EIO; |
| 67 | |
| 68 | ghp->crc_length = len - CRC24_LENGTH; |
| 69 | |
| 70 | ghp->ack_req = 0; |
| 71 | |
| 72 | /* Section 5.5: FCS */ |
| 73 | ghp->fcs = *(llc_hdr + len - 3); |
| 74 | ghp->fcs |= *(llc_hdr + len - 2) << 8; |
| 75 | ghp->fcs |= *(llc_hdr + len - 1) << 16; |
| 76 | |
| 77 | /* Section 6.2.1: invalid PD field */ |
| 78 | if (llc_hdr[0] & 0x80) |
| 79 | return -EIO; |
| 80 | |
| 81 | /* This only works for the MS->SGSN direction */ |
| 82 | if (llc_hdr[0] & 0x40) |
| 83 | ghp->is_cmd = 0; |
| 84 | else |
| 85 | ghp->is_cmd = 1; |
| 86 | |
| 87 | ghp->sapi = llc_hdr[0] & 0xf; |
| 88 | |
| 89 | /* Section 6.2.3: check for reserved SAPI */ |
| 90 | switch (ghp->sapi) { |
| 91 | case 0: |
| 92 | case 4: |
| 93 | case 6: |
| 94 | case 0xa: |
| 95 | case 0xc: |
| 96 | case 0xd: |
| 97 | case 0xf: |
| 98 | return -EINVAL; |
| 99 | } |
| 100 | |
| 101 | if ((ctrl[0] & 0x80) == 0) { |
| 102 | /* I (Information transfer + Supervisory) format */ |
| 103 | uint8_t k; |
| 104 | |
| 105 | ghp->data = ctrl + 3; |
| 106 | |
| 107 | if (ctrl[0] & 0x40) |
| 108 | ghp->ack_req = 1; |
| 109 | |
| 110 | ghp->seq_tx = (ctrl[0] & 0x1f) << 4; |
| 111 | ghp->seq_tx |= (ctrl[1] >> 4); |
| 112 | |
| 113 | ghp->seq_rx = (ctrl[1] & 0x7) << 6; |
| 114 | ghp->seq_rx |= (ctrl[2] >> 2); |
| 115 | |
| 116 | switch (ctrl[2] & 0x03) { |
| 117 | case 0: |
| 118 | ghp->cmd = GPRS_LLC_RR; |
| 119 | break; |
| 120 | case 1: |
| 121 | ghp->cmd = GPRS_LLC_ACK; |
| 122 | break; |
| 123 | case 2: |
| 124 | ghp->cmd = GPRS_LLC_RNR; |
| 125 | break; |
| 126 | case 3: |
| 127 | ghp->cmd = GPRS_LLC_SACK; |
| 128 | k = ctrl[3] & 0x1f; |
| 129 | ghp->data += 1 + k; |
| 130 | break; |
| 131 | } |
| 132 | ghp->data_len = (llc_hdr + len - 3) - ghp->data; |
| 133 | } else if ((ctrl[0] & 0xc0) == 0x80) { |
| 134 | /* S (Supervisory) format */ |
| 135 | ghp->data = NULL; |
| 136 | ghp->data_len = 0; |
| 137 | |
| 138 | if (ctrl[0] & 0x20) |
| 139 | ghp->ack_req = 1; |
| 140 | ghp->seq_rx = (ctrl[0] & 0x7) << 6; |
| 141 | ghp->seq_rx |= (ctrl[1] >> 2); |
| 142 | |
| 143 | switch (ctrl[1] & 0x03) { |
| 144 | case 0: |
| 145 | ghp->cmd = GPRS_LLC_RR; |
| 146 | break; |
| 147 | case 1: |
| 148 | ghp->cmd = GPRS_LLC_ACK; |
| 149 | break; |
| 150 | case 2: |
| 151 | ghp->cmd = GPRS_LLC_RNR; |
| 152 | break; |
| 153 | case 3: |
| 154 | ghp->cmd = GPRS_LLC_SACK; |
| 155 | break; |
| 156 | } |
| 157 | } else if ((ctrl[0] & 0xe0) == 0xc0) { |
| 158 | /* UI (Unconfirmed Inforamtion) format */ |
| 159 | ghp->cmd = GPRS_LLC_UI; |
| 160 | ghp->data = ctrl + 2; |
| 161 | ghp->data_len = (llc_hdr + len - 3) - ghp->data; |
| 162 | |
| 163 | ghp->seq_tx = (ctrl[0] & 0x7) << 6; |
| 164 | ghp->seq_tx |= (ctrl[1] >> 2); |
| 165 | if (ctrl[1] & 0x02) { |
| 166 | ghp->is_encrypted = 1; |
| 167 | /* FIXME: encryption */ |
| 168 | } |
| 169 | if (ctrl[1] & 0x01) { |
| 170 | /* FCS over hdr + all inf fields */ |
| 171 | } else { |
| 172 | /* FCS over hdr + N202 octets (4) */ |
| 173 | if (ghp->crc_length > UI_HDR_LEN + N202) |
| 174 | ghp->crc_length = UI_HDR_LEN + N202; |
| 175 | } |
| 176 | } else { |
| 177 | /* U (Unnumbered) format: 1 1 1 P/F M4 M3 M2 M1 */ |
| 178 | ghp->data = NULL; |
| 179 | ghp->data_len = 0; |
| 180 | |
| 181 | switch (ctrl[0] & 0xf) { |
| 182 | case GPRS_LLC_U_NULL_CMD: |
| 183 | ghp->cmd = GPRS_LLC_NULL; |
| 184 | break; |
| 185 | case GPRS_LLC_U_DM_RESP: |
| 186 | ghp->cmd = GPRS_LLC_DM; |
| 187 | break; |
| 188 | case GPRS_LLC_U_DISC_CMD: |
| 189 | ghp->cmd = GPRS_LLC_DISC; |
| 190 | break; |
| 191 | case GPRS_LLC_U_UA_RESP: |
| 192 | ghp->cmd = GPRS_LLC_UA; |
| 193 | break; |
| 194 | case GPRS_LLC_U_SABM_CMD: |
| 195 | ghp->cmd = GPRS_LLC_SABM; |
| 196 | break; |
| 197 | case GPRS_LLC_U_FRMR_RESP: |
| 198 | ghp->cmd = GPRS_LLC_FRMR; |
| 199 | break; |
| 200 | case GPRS_LLC_U_XID: |
| 201 | ghp->cmd = GPRS_LLC_XID; |
| 202 | ghp->data = ctrl + 1; |
| 203 | ghp->data_len = (llc_hdr + len - 3) - ghp->data; |
| 204 | break; |
| 205 | default: |
| 206 | return -EIO; |
| 207 | } |
| 208 | } |
| 209 | |
| 210 | /* FIXME: parse sack frame */ |
| 211 | if (ghp->cmd == GPRS_LLC_SACK) { |
| 212 | LOGP(DPCU, LOGL_NOTICE, "Unsupported SACK frame\n"); |
| 213 | return -EIO; |
| 214 | } |
| 215 | |
| 216 | return 0; |
| 217 | } |
Holger Hans Peter Freyther | 9d93838 | 2013-07-31 21:59:29 +0200 | [diff] [blame] | 218 | |
| 219 | const struct tlv_definition gsm48_gmm_att_tlvdef = { |
| 220 | .def = { |
| 221 | [GSM48_IE_GMM_CIPH_CKSN] = { TLV_TYPE_FIXED, 1 }, |
| 222 | [GSM48_IE_GMM_TIMER_READY] = { TLV_TYPE_TV, 1 }, |
| 223 | [GSM48_IE_GMM_ALLOC_PTMSI] = { TLV_TYPE_TLV, 0 }, |
| 224 | [GSM48_IE_GMM_PTMSI_SIG] = { TLV_TYPE_FIXED, 3 }, |
| 225 | [GSM48_IE_GMM_AUTH_RAND] = { TLV_TYPE_FIXED, 16 }, |
| 226 | [GSM48_IE_GMM_AUTH_SRES] = { TLV_TYPE_FIXED, 4 }, |
| 227 | [GSM48_IE_GMM_IMEISV] = { TLV_TYPE_TLV, 0 }, |
| 228 | [GSM48_IE_GMM_DRX_PARAM] = { TLV_TYPE_FIXED, 2 }, |
| 229 | [GSM48_IE_GMM_MS_NET_CAPA] = { TLV_TYPE_TLV, 0 }, |
| 230 | [GSM48_IE_GMM_PDP_CTX_STATUS] = { TLV_TYPE_TLV, 0 }, |
| 231 | [GSM48_IE_GMM_PS_LCS_CAPA] = { TLV_TYPE_TLV, 0 }, |
| 232 | [GSM48_IE_GMM_GMM_MBMS_CTX_ST] = { TLV_TYPE_TLV, 0 }, |
| 233 | }, |
| 234 | }; |