| /* GPRS LLC protocol implementation as per 3GPP TS 04.64 */ |
| |
| /* (C) 2009-2010 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 Affero General Public License as published by |
| * the Free Software Foundation; either version 3 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 Affero General Public License for more details. |
| * |
| * You should have received a copy of the GNU Affero General Public License |
| * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| * |
| */ |
| |
| #include <errno.h> |
| #include <stdint.h> |
| |
| #include <osmocom/core/msgb.h> |
| #include <osmocom/core/linuxlist.h> |
| #include <osmocom/core/timer.h> |
| #include <osmocom/core/talloc.h> |
| |
| #include <openbsc/gsm_data.h> |
| #include <openbsc/debug.h> |
| #include <openbsc/gprs_sgsn.h> |
| #include <openbsc/gprs_gmm.h> |
| #include <openbsc/gprs_bssgp.h> |
| #include <openbsc/gprs_llc.h> |
| #include <openbsc/crc24.h> |
| |
| /* Section 8.9.9 LLC layer parameter default values */ |
| static const struct gprs_llc_params llc_default_params[] = { |
| [1] = { |
| .t200_201 = 5, |
| .n200 = 3, |
| .n201_u = 400, |
| }, |
| [2] = { |
| .t200_201 = 5, |
| .n200 = 3, |
| .n201_u = 270, |
| }, |
| [3] = { |
| .iov_i_exp = 27, |
| .t200_201 = 5, |
| .n200 = 3, |
| .n201_u = 500, |
| .n201_i = 1503, |
| .mD = 1520, |
| .mU = 1520, |
| .kD = 16, |
| .kU = 16, |
| }, |
| [5] = { |
| .iov_i_exp = 27, |
| .t200_201 = 10, |
| .n200 = 3, |
| .n201_u = 500, |
| .n201_i = 1503, |
| .mD = 760, |
| .mU = 760, |
| .kD = 8, |
| .kU = 8, |
| }, |
| [7] = { |
| .t200_201 = 20, |
| .n200 = 3, |
| .n201_u = 270, |
| }, |
| [8] = { |
| .t200_201 = 20, |
| .n200 = 3, |
| .n201_u = 270, |
| }, |
| [9] = { |
| .iov_i_exp = 27, |
| .t200_201 = 20, |
| .n200 = 3, |
| .n201_u = 500, |
| .n201_i = 1503, |
| .mD = 380, |
| .mU = 380, |
| .kD = 4, |
| .kU = 4, |
| }, |
| [11] = { |
| .iov_i_exp = 27, |
| .t200_201 = 40, |
| .n200 = 3, |
| .n201_u = 500, |
| .n201_i = 1503, |
| .mD = 190, |
| .mU = 190, |
| .kD = 2, |
| .kU = 2, |
| }, |
| }; |
| |
| LLIST_HEAD(gprs_llc_llmes); |
| void *llc_tall_ctx; |
| |
| /* If the TLLI is foreign, return its local version */ |
| static inline uint32_t tlli_foreign2local(uint32_t tlli) |
| { |
| uint32_t new_tlli; |
| |
| if (gprs_tlli_type(tlli) == TLLI_FOREIGN) { |
| new_tlli = tlli | 0x40000000; |
| DEBUGP(DLLC, "TLLI 0x%08x is foreign, converting to " |
| "local TLLI 0x%08x\n", tlli, new_tlli); |
| } else |
| new_tlli = tlli; |
| |
| return new_tlli; |
| } |
| |
| /* lookup LLC Entity based on DLCI (TLLI+SAPI tuple) */ |
| static struct gprs_llc_lle *lle_by_tlli_sapi(uint32_t tlli, uint8_t sapi) |
| { |
| struct gprs_llc_llme *llme; |
| |
| tlli = tlli_foreign2local(tlli); |
| |
| llist_for_each_entry(llme, &gprs_llc_llmes, list) { |
| if (llme->tlli == tlli || llme->old_tlli == tlli) |
| return &llme->lle[sapi]; |
| } |
| return NULL; |
| } |
| |
| static void lle_init(struct gprs_llc_llme *llme, uint8_t sapi) |
| { |
| struct gprs_llc_lle *lle = &llme->lle[sapi]; |
| |
| lle->llme = llme; |
| lle->sapi = sapi; |
| lle->state = GPRS_LLES_UNASSIGNED; |
| |
| /* Initialize according to parameters */ |
| memcpy(&lle->params, &llc_default_params[sapi], sizeof(lle->params)); |
| } |
| |
| static struct gprs_llc_llme *llme_alloc(uint32_t tlli) |
| { |
| struct gprs_llc_llme *llme; |
| uint32_t i; |
| |
| llme = talloc_zero(llc_tall_ctx, struct gprs_llc_llme); |
| if (!llme) |
| return NULL; |
| |
| llme->tlli = tlli; |
| llme->old_tlli = 0xffffffff; |
| llme->state = GPRS_LLMS_UNASSIGNED; |
| |
| for (i = 0; i < ARRAY_SIZE(llme->lle); i++) |
| lle_init(llme, i); |
| |
| llist_add(&llme->list, &gprs_llc_llmes); |
| |
| return llme; |
| } |
| |
| static void llme_free(struct gprs_llc_llme *llme) |
| { |
| llist_del(&llme->list); |
| talloc_free(llme); |
| } |
| |
| enum gprs_llc_cmd { |
| GPRS_LLC_NULL, |
| GPRS_LLC_RR, |
| GPRS_LLC_ACK, |
| GPRS_LLC_RNR, |
| GPRS_LLC_SACK, |
| GPRS_LLC_DM, |
| GPRS_LLC_DISC, |
| GPRS_LLC_UA, |
| GPRS_LLC_SABM, |
| GPRS_LLC_FRMR, |
| GPRS_LLC_XID, |
| GPRS_LLC_UI, |
| }; |
| |
| static const struct value_string llc_cmd_strs[] = { |
| { GPRS_LLC_NULL, "NULL" }, |
| { GPRS_LLC_RR, "RR" }, |
| { GPRS_LLC_ACK, "ACK" }, |
| { GPRS_LLC_RNR, "RNR" }, |
| { GPRS_LLC_SACK, "SACK" }, |
| { GPRS_LLC_DM, "DM" }, |
| { GPRS_LLC_DISC, "DISC" }, |
| { GPRS_LLC_UA, "UA" }, |
| { GPRS_LLC_SABM, "SABM" }, |
| { GPRS_LLC_FRMR, "FRMR" }, |
| { GPRS_LLC_XID, "XID" }, |
| { GPRS_LLC_UI, "UI" }, |
| { 0, NULL } |
| }; |
| |
| struct gprs_llc_hdr_parsed { |
| uint8_t sapi; |
| uint8_t is_cmd:1, |
| ack_req:1, |
| is_encrypted:1; |
| uint32_t seq_rx; |
| uint32_t seq_tx; |
| uint32_t fcs; |
| uint32_t fcs_calc; |
| uint8_t *data; |
| uint16_t data_len; |
| uint16_t crc_length; |
| enum gprs_llc_cmd cmd; |
| }; |
| |
| #define LLC_ALLOC_SIZE 16384 |
| #define UI_HDR_LEN 3 |
| #define N202 4 |
| #define CRC24_LENGTH 3 |
| |
| static int gprs_llc_fcs(uint8_t *data, unsigned int len) |
| { |
| uint32_t fcs_calc; |
| |
| fcs_calc = crc24_calc(INIT_CRC24, data, len); |
| fcs_calc = ~fcs_calc; |
| fcs_calc &= 0xffffff; |
| |
| return fcs_calc; |
| } |
| |
| static void t200_expired(void *data) |
| { |
| struct gprs_llc_lle *lle = data; |
| |
| /* 8.5.1.3: Expiry of T200 */ |
| |
| if (lle->retrans_ctr >= lle->params.n200) { |
| /* FIXME: LLGM-STATUS-IND, LL-RELEASE-IND/CNF */ |
| lle->state = GPRS_LLES_ASSIGNED_ADM; |
| } |
| |
| switch (lle->state) { |
| case GPRS_LLES_LOCAL_EST: |
| /* FIXME: retransmit SABM */ |
| /* FIXME: re-start T200 */ |
| lle->retrans_ctr++; |
| break; |
| case GPRS_LLES_LOCAL_REL: |
| /* FIXME: retransmit DISC */ |
| /* FIXME: re-start T200 */ |
| lle->retrans_ctr++; |
| break; |
| } |
| |
| } |
| |
| static void t201_expired(void *data) |
| { |
| struct gprs_llc_lle *lle = data; |
| |
| if (lle->retrans_ctr < lle->params.n200) { |
| /* FIXME: transmit apropriate supervisory frame (8.6.4.1) */ |
| /* FIXME: set timer T201 */ |
| lle->retrans_ctr++; |
| } |
| } |
| |
| int gprs_llc_tx_u(struct msgb *msg, uint8_t sapi, int command, |
| enum gprs_llc_u_cmd u_cmd, int pf_bit) |
| { |
| uint8_t *fcs, *llch; |
| uint8_t addr, ctrl; |
| uint32_t fcs_calc; |
| |
| /* Identifiers from UP: (TLLI, SAPI) + (BVCI, NSEI) */ |
| |
| /* Address Field */ |
| addr = sapi & 0xf; |
| if (command) |
| addr |= 0x40; |
| |
| /* 6.3 Figure 8 */ |
| ctrl = 0xe0 | u_cmd; |
| if (pf_bit) |
| ctrl |= 0x10; |
| |
| /* prepend LLC UI header */ |
| llch = msgb_push(msg, 2); |
| llch[0] = addr; |
| llch[1] = ctrl; |
| |
| /* append FCS to end of frame */ |
| fcs = msgb_put(msg, 3); |
| fcs_calc = gprs_llc_fcs(llch, fcs - llch); |
| fcs[0] = fcs_calc & 0xff; |
| fcs[1] = (fcs_calc >> 8) & 0xff; |
| fcs[2] = (fcs_calc >> 16) & 0xff; |
| |
| /* Identifiers passed down: (BVCI, NSEI) */ |
| |
| /* Send BSSGP-DL-UNITDATA.req */ |
| return gprs_bssgp_tx_dl_ud(msg, NULL); |
| } |
| |
| /* Send XID response to LLE */ |
| static int gprs_llc_tx_xid(struct gprs_llc_lle *lle, struct msgb *msg) |
| { |
| /* copy identifiers from LLE to ensure lower layers can route */ |
| msgb_tlli(msg) = lle->llme->tlli; |
| msgb_bvci(msg) = lle->llme->bvci; |
| msgb_nsei(msg) = lle->llme->nsei; |
| |
| return gprs_llc_tx_u(msg, lle->sapi, 0, GPRS_LLC_U_XID, 1); |
| } |
| |
| /* Transmit a UI frame over the given SAPI */ |
| int gprs_llc_tx_ui(struct msgb *msg, uint8_t sapi, int command, |
| void *mmctx) |
| { |
| struct gprs_llc_lle *lle; |
| uint8_t *fcs, *llch; |
| uint8_t addr, ctrl[2]; |
| uint32_t fcs_calc; |
| uint16_t nu = 0; |
| uint32_t oc; |
| |
| /* Identifiers from UP: (TLLI, SAPI) + (BVCI, NSEI) */ |
| |
| /* look-up or create the LL Entity for this (TLLI, SAPI) tuple */ |
| lle = lle_by_tlli_sapi(msgb_tlli(msg), sapi); |
| if (!lle) { |
| struct gprs_llc_llme *llme; |
| LOGP(DLLC, LOGL_ERROR, "LLC TX: unknown TLLI 0x%08x, " |
| "creating LLME on the fly\n", msgb_tlli(msg)); |
| llme = llme_alloc(msgb_tlli(msg)); |
| lle = &llme->lle[sapi]; |
| } |
| |
| if (msg->len > lle->params.n201_u) { |
| LOGP(DLLC, LOGL_ERROR, "Cannot Tx %u bytes (N201-U=%u)\n", |
| msg->len, lle->params.n201_u); |
| return -EFBIG; |
| } |
| |
| /* Update LLE's (BVCI, NSEI) tuple */ |
| lle->llme->bvci = msgb_bvci(msg); |
| lle->llme->nsei = msgb_nsei(msg); |
| |
| /* Obtain current values for N(u) and OC */ |
| nu = lle->vu_send; |
| oc = lle->oc_ui_send; |
| /* Increment V(U) */ |
| lle->vu_send = (lle->vu_send + 1) % 512; |
| /* Increment Overflow Counter, if needed */ |
| if ((lle->vu_send + 1) / 512) |
| lle->oc_ui_send += 512; |
| |
| /* Address Field */ |
| addr = sapi & 0xf; |
| if (command) |
| addr |= 0x40; |
| |
| /* Control Field */ |
| ctrl[0] = 0xc0; |
| ctrl[0] |= nu >> 6; |
| ctrl[1] = (nu << 2) & 0xfc; |
| ctrl[1] |= 0x01; /* Protected Mode */ |
| |
| /* prepend LLC UI header */ |
| llch = msgb_push(msg, 3); |
| llch[0] = addr; |
| llch[1] = ctrl[0]; |
| llch[2] = ctrl[1]; |
| |
| /* append FCS to end of frame */ |
| fcs = msgb_put(msg, 3); |
| fcs_calc = gprs_llc_fcs(llch, fcs - llch); |
| fcs[0] = fcs_calc & 0xff; |
| fcs[1] = (fcs_calc >> 8) & 0xff; |
| fcs[2] = (fcs_calc >> 16) & 0xff; |
| |
| /* encrypt information field + FCS, if needed! */ |
| if (lle->llme->algo != GPRS_ALGO_GEA0) { |
| uint32_t iov_ui = 0; /* FIXME: randomly select for TLLI */ |
| uint16_t crypt_len = (fcs + 3) - (llch + 3); |
| uint8_t cipher_out[GSM0464_CIPH_MAX_BLOCK]; |
| uint32_t iv; |
| int rc, i; |
| uint64_t kc = *(uint64_t *)&lle->llme->kc; |
| |
| /* Compute the 'Input' Paraemeter */ |
| iv = gprs_cipher_gen_input_ui(iov_ui, sapi, nu, oc); |
| |
| /* Compute the keystream that we need to XOR with the data */ |
| rc = gprs_cipher_run(cipher_out, crypt_len, lle->llme->algo, |
| kc, iv, GPRS_CIPH_SGSN2MS); |
| if (rc < 0) { |
| LOGP(DLLC, LOGL_ERROR, "Error crypting UI frame: %d\n", rc); |
| return rc; |
| } |
| |
| /* XOR the cipher output with the information field + FCS */ |
| for (i = 0; i < crypt_len; i++) |
| *(llch + 3 + i) ^= cipher_out[i]; |
| |
| /* Mark frame as encrypted */ |
| ctrl[1] |= 0x02; |
| } |
| |
| /* Identifiers passed down: (BVCI, NSEI) */ |
| |
| /* Send BSSGP-DL-UNITDATA.req */ |
| return gprs_bssgp_tx_dl_ud(msg, mmctx); |
| } |
| |
| static void gprs_llc_hdr_dump(struct gprs_llc_hdr_parsed *gph) |
| { |
| DEBUGP(DLLC, "LLC SAPI=%u %c %c FCS=0x%06x", |
| gph->sapi, gph->is_cmd ? 'C' : 'R', gph->ack_req ? 'A' : ' ', |
| gph->fcs); |
| |
| if (gph->cmd) |
| DEBUGPC(DLLC, "CMD=%s ", get_value_string(llc_cmd_strs, gph->cmd)); |
| |
| if (gph->data) |
| DEBUGPC(DLLC, "DATA "); |
| |
| DEBUGPC(DLLC, "\n"); |
| } |
| static int gprs_llc_hdr_rx(struct gprs_llc_hdr_parsed *gph, |
| struct gprs_llc_lle *lle) |
| { |
| switch (gph->cmd) { |
| case GPRS_LLC_SABM: /* Section 6.4.1.1 */ |
| lle->v_sent = lle->v_ack = lle->v_recv = 0; |
| if (lle->state == GPRS_LLES_ASSIGNED_ADM) { |
| /* start re-establishment (8.7.1) */ |
| } |
| lle->state = GPRS_LLES_REMOTE_EST; |
| /* FIXME: Send UA */ |
| lle->state = GPRS_LLES_ABM; |
| /* FIXME: process data */ |
| break; |
| case GPRS_LLC_DISC: /* Section 6.4.1.2 */ |
| /* FIXME: Send UA */ |
| /* terminate ABM */ |
| lle->state = GPRS_LLES_ASSIGNED_ADM; |
| break; |
| case GPRS_LLC_UA: /* Section 6.4.1.3 */ |
| if (lle->state == GPRS_LLES_LOCAL_EST) |
| lle->state = GPRS_LLES_ABM; |
| break; |
| case GPRS_LLC_DM: /* Section 6.4.1.4: ABM cannot be performed */ |
| if (lle->state == GPRS_LLES_LOCAL_EST) |
| lle->state = GPRS_LLES_ASSIGNED_ADM; |
| break; |
| case GPRS_LLC_FRMR: /* Section 6.4.1.5 */ |
| break; |
| case GPRS_LLC_XID: /* Section 6.4.1.6 */ |
| /* FIXME: implement XID negotiation using SNDCP */ |
| { |
| struct msgb *resp; |
| uint8_t *xid; |
| resp = msgb_alloc_headroom(4096, 1024, "LLC_XID"); |
| xid = msgb_put(resp, gph->data_len); |
| memcpy(xid, gph->data, gph->data_len); |
| gprs_llc_tx_xid(lle, resp); |
| } |
| break; |
| case GPRS_LLC_UI: |
| if (gph->seq_tx < lle->vu_recv) { |
| LOGP(DLLC, LOGL_NOTICE, "TLLI=%08x dropping UI, vurecv %u <= %u\n", |
| lle->llme ? lle->llme->tlli : -1, |
| gph->seq_tx, lle->vu_recv); |
| return -EIO; |
| } |
| /* Increment the sequence number that we expect in the next frame */ |
| lle->vu_recv = (gph->seq_tx + 1) % 512; |
| /* Increment Overflow Counter */ |
| if ((gph->seq_tx + 1) / 512) |
| lle->oc_ui_recv += 512; |
| break; |
| } |
| |
| return 0; |
| } |
| |
| /* parse a GPRS LLC header, also check for invalid frames */ |
| static int gprs_llc_hdr_parse(struct gprs_llc_hdr_parsed *ghp, |
| uint8_t *llc_hdr, int len) |
| { |
| uint8_t *ctrl = llc_hdr+1; |
| int is_sack = 0; |
| |
| if (len <= CRC24_LENGTH) |
| return -EIO; |
| |
| ghp->crc_length = len - CRC24_LENGTH; |
| |
| ghp->ack_req = 0; |
| |
| /* Section 5.5: FCS */ |
| ghp->fcs = *(llc_hdr + len - 3); |
| ghp->fcs |= *(llc_hdr + len - 2) << 8; |
| ghp->fcs |= *(llc_hdr + len - 1) << 16; |
| |
| /* Section 6.2.1: invalid PD field */ |
| if (llc_hdr[0] & 0x80) |
| return -EIO; |
| |
| /* This only works for the MS->SGSN direction */ |
| if (llc_hdr[0] & 0x40) |
| ghp->is_cmd = 0; |
| else |
| ghp->is_cmd = 1; |
| |
| ghp->sapi = llc_hdr[0] & 0xf; |
| |
| /* Section 6.2.3: check for reserved SAPI */ |
| switch (ghp->sapi) { |
| case 0: |
| case 4: |
| case 6: |
| case 0xa: |
| case 0xc: |
| case 0xd: |
| case 0xf: |
| return -EINVAL; |
| } |
| |
| if ((ctrl[0] & 0x80) == 0) { |
| /* I (Information transfer + Supervisory) format */ |
| uint8_t k; |
| |
| ghp->data = ctrl + 3; |
| |
| if (ctrl[0] & 0x40) |
| ghp->ack_req = 1; |
| |
| ghp->seq_tx = (ctrl[0] & 0x1f) << 4; |
| ghp->seq_tx |= (ctrl[1] >> 4); |
| |
| ghp->seq_rx = (ctrl[1] & 0x7) << 6; |
| ghp->seq_rx |= (ctrl[2] >> 2); |
| |
| switch (ctrl[2] & 0x03) { |
| case 0: |
| ghp->cmd = GPRS_LLC_RR; |
| break; |
| case 1: |
| ghp->cmd = GPRS_LLC_ACK; |
| break; |
| case 2: |
| ghp->cmd = GPRS_LLC_RNR; |
| break; |
| case 3: |
| ghp->cmd = GPRS_LLC_SACK; |
| k = ctrl[3] & 0x1f; |
| ghp->data += 1 + k; |
| break; |
| } |
| ghp->data_len = (llc_hdr + len - 3) - ghp->data; |
| } else if ((ctrl[0] & 0xc0) == 0x80) { |
| /* S (Supervisory) format */ |
| ghp->data = NULL; |
| ghp->data_len = 0; |
| |
| if (ctrl[0] & 0x20) |
| ghp->ack_req = 1; |
| ghp->seq_rx = (ctrl[0] & 0x7) << 6; |
| ghp->seq_rx |= (ctrl[1] >> 2); |
| |
| switch (ctrl[1] & 0x03) { |
| case 0: |
| ghp->cmd = GPRS_LLC_RR; |
| break; |
| case 1: |
| ghp->cmd = GPRS_LLC_ACK; |
| break; |
| case 2: |
| ghp->cmd = GPRS_LLC_RNR; |
| break; |
| case 3: |
| ghp->cmd = GPRS_LLC_SACK; |
| break; |
| } |
| } else if ((ctrl[0] & 0xe0) == 0xc0) { |
| /* UI (Unconfirmed Inforamtion) format */ |
| ghp->cmd = GPRS_LLC_UI; |
| ghp->data = ctrl + 2; |
| ghp->data_len = (llc_hdr + len - 3) - ghp->data; |
| |
| ghp->seq_tx = (ctrl[0] & 0x7) << 6; |
| ghp->seq_tx |= (ctrl[1] >> 2); |
| if (ctrl[1] & 0x02) { |
| ghp->is_encrypted = 1; |
| /* FIXME: encryption */ |
| } |
| if (ctrl[1] & 0x01) { |
| /* FCS over hdr + all inf fields */ |
| } else { |
| /* FCS over hdr + N202 octets (4) */ |
| if (ghp->crc_length > UI_HDR_LEN + N202) |
| ghp->crc_length = UI_HDR_LEN + N202; |
| } |
| } else { |
| /* U (Unnumbered) format: 1 1 1 P/F M4 M3 M2 M1 */ |
| ghp->data = NULL; |
| ghp->data_len = 0; |
| |
| switch (ctrl[0] & 0xf) { |
| case GPRS_LLC_U_NULL_CMD: |
| ghp->cmd = GPRS_LLC_NULL; |
| break; |
| case GPRS_LLC_U_DM_RESP: |
| ghp->cmd = GPRS_LLC_DM; |
| break; |
| case GPRS_LLC_U_DISC_CMD: |
| ghp->cmd = GPRS_LLC_DISC; |
| break; |
| case GPRS_LLC_U_UA_RESP: |
| ghp->cmd = GPRS_LLC_UA; |
| break; |
| case GPRS_LLC_U_SABM_CMD: |
| ghp->cmd = GPRS_LLC_SABM; |
| break; |
| case GPRS_LLC_U_FRMR_RESP: |
| ghp->cmd = GPRS_LLC_FRMR; |
| break; |
| case GPRS_LLC_U_XID: |
| ghp->cmd = GPRS_LLC_XID; |
| ghp->data = ctrl + 1; |
| ghp->data_len = (llc_hdr + len - 3) - ghp->data; |
| break; |
| default: |
| return -EIO; |
| } |
| } |
| |
| /* FIXME: parse sack frame */ |
| if (ghp->cmd == GPRS_LLC_SACK) { |
| LOGP(DLLC, LOGL_NOTICE, "Unsupported SACK frame\n"); |
| return -EIO; |
| } |
| |
| return 0; |
| } |
| |
| /* receive an incoming LLC PDU (BSSGP-UL-UNITDATA-IND, 7.2.4.2) */ |
| int gprs_llc_rcvmsg(struct msgb *msg, struct tlv_parsed *tv) |
| { |
| struct bssgp_ud_hdr *udh = (struct bssgp_ud_hdr *) msgb_bssgph(msg); |
| struct gprs_llc_hdr *lh = msgb_llch(msg); |
| struct gprs_llc_hdr_parsed llhp; |
| struct gprs_llc_lle *lle; |
| int rc = 0; |
| |
| /* Identifiers from DOWN: NSEI, BVCI, TLLI */ |
| |
| memset(&llhp, 0, sizeof(llhp)); |
| rc = gprs_llc_hdr_parse(&llhp, (uint8_t *) lh, TLVP_LEN(tv, BSSGP_IE_LLC_PDU)); |
| gprs_llc_hdr_dump(&llhp); |
| if (rc < 0) { |
| LOGP(DLLC, LOGL_NOTICE, "Error during LLC header parsing\n"); |
| return rc; |
| } |
| |
| switch (gprs_tlli_type(msgb_tlli(msg))) { |
| case TLLI_LOCAL: |
| case TLLI_FOREIGN: |
| case TLLI_RANDOM: |
| case TLLI_AUXILIARY: |
| break; |
| default: |
| LOGP(DLLC, LOGL_ERROR, |
| "Discarding frame with strange TLLI type\n"); |
| break; |
| } |
| |
| /* find the LLC Entity for this TLLI+SAPI tuple */ |
| lle = lle_by_tlli_sapi(msgb_tlli(msg), llhp.sapi); |
| |
| /* 7.2.1.1 LLC belonging to unassigned TLLI+SAPI shall be discarded, |
| * except UID and XID frames with SAPI=1 */ |
| if (!lle) { |
| if (llhp.sapi == GPRS_SAPI_GMM && |
| (llhp.cmd == GPRS_LLC_XID || llhp.cmd == GPRS_LLC_UI)) { |
| struct gprs_llc_llme *llme; |
| /* FIXME: don't use the TLLI but the 0xFFFF unassigned? */ |
| llme = llme_alloc(msgb_tlli(msg)); |
| LOGP(DLLC, LOGL_DEBUG, "LLC RX: unknown TLLI 0x08x, " |
| "creating LLME on the fly\n", msgb_tlli(msg)); |
| lle = &llme->lle[llhp.sapi]; |
| } else { |
| LOGP(DLLC, LOGL_NOTICE, |
| "unknown TLLI/SAPI: Silently dropping\n"); |
| return 0; |
| } |
| } |
| |
| /* decrypt information field + FCS, if needed! */ |
| if (llhp.is_encrypted) { |
| uint32_t iov_ui = 0; /* FIXME: randomly select for TLLI */ |
| uint16_t crypt_len = llhp.data_len + 3; |
| uint8_t cipher_out[GSM0464_CIPH_MAX_BLOCK]; |
| uint32_t iv; |
| uint64_t kc = *(uint64_t *)&lle->llme->kc; |
| int rc, i; |
| |
| if (lle->llme->algo == GPRS_ALGO_GEA0) { |
| LOGP(DLLC, LOGL_NOTICE, "encrypted frame for LLC that " |
| "has no KC/Algo! Dropping.\n"); |
| return 0; |
| } |
| |
| iv = gprs_cipher_gen_input_ui(iov_ui, lle->sapi, llhp.seq_tx, |
| lle->oc_ui_recv); |
| rc = gprs_cipher_run(cipher_out, crypt_len, lle->llme->algo, |
| kc, iv, GPRS_CIPH_MS2SGSN); |
| if (rc < 0) { |
| LOGP(DLLC, LOGL_ERROR, "Error decrypting frame: %d\n", |
| rc); |
| return rc; |
| } |
| |
| /* XOR the cipher output with the information field + FCS */ |
| for (i = 0; i < crypt_len; i++) |
| *(llhp.data + i) ^= cipher_out[i]; |
| } else { |
| if (lle->llme->algo != GPRS_ALGO_GEA0) { |
| LOGP(DLLC, LOGL_NOTICE, "unencrypted frame for LLC " |
| "that is supposed to be encrypted. Dropping.\n"); |
| return 0; |
| } |
| } |
| |
| /* We have to do the FCS check _after_ decryption */ |
| llhp.fcs_calc = gprs_llc_fcs((uint8_t *)lh, llhp.crc_length); |
| if (llhp.fcs != llhp.fcs_calc) { |
| LOGP(DLLC, LOGL_INFO, "Dropping frame with invalid FCS\n"); |
| return -EIO; |
| } |
| |
| /* Update LLE's (BVCI, NSEI) tuple */ |
| lle->llme->bvci = msgb_bvci(msg); |
| lle->llme->nsei = msgb_nsei(msg); |
| |
| /* Receive and Process the actual LLC frame */ |
| rc = gprs_llc_hdr_rx(&llhp, lle); |
| if (rc < 0) |
| return rc; |
| |
| /* llhp.data is only set when we need to send LL_[UNIT]DATA_IND up */ |
| if (llhp.data) { |
| msgb_gmmh(msg) = llhp.data; |
| switch (llhp.sapi) { |
| case GPRS_SAPI_GMM: |
| /* send LL_UNITDATA_IND to GMM */ |
| rc = gsm0408_gprs_rcvmsg(msg, lle->llme); |
| break; |
| case GPRS_SAPI_SNDCP3: |
| case GPRS_SAPI_SNDCP5: |
| case GPRS_SAPI_SNDCP9: |
| case GPRS_SAPI_SNDCP11: |
| /* send LL_DATA_IND/LL_UNITDATA_IND to SNDCP */ |
| rc = sndcp_llunitdata_ind(msg, lle, llhp.data, llhp.data_len); |
| break; |
| case GPRS_SAPI_SMS: |
| /* FIXME */ |
| case GPRS_SAPI_TOM2: |
| case GPRS_SAPI_TOM8: |
| /* FIXME: send LL_DATA_IND/LL_UNITDATA_IND to TOM */ |
| default: |
| LOGP(DLLC, LOGL_NOTICE, "Unsupported SAPI %u\n", llhp.sapi); |
| rc = -EINVAL; |
| break; |
| } |
| } |
| |
| return rc; |
| } |
| |
| /* 04.64 Chapter 7.2.1.1 LLGMM-ASSIGN */ |
| int gprs_llgmm_assign(struct gprs_llc_llme *llme, |
| uint32_t old_tlli, uint32_t new_tlli, |
| enum gprs_ciph_algo alg, const uint8_t *kc) |
| { |
| unsigned int i; |
| |
| /* Update the crypto parameters */ |
| llme->algo = alg; |
| if (alg != GPRS_ALGO_GEA0) |
| memcpy(llme->kc, kc, sizeof(llme->kc)); |
| |
| if (old_tlli == 0xffffffff && new_tlli != 0xffffffff) { |
| /* TLLI Assignment 8.3.1 */ |
| /* New TLLI shall be assigned and used when (re)transmitting LLC frames */ |
| /* If old TLLI != 0xffffffff was assigned to LLME, then TLLI |
| * old is unassigned. Only TLLI new shall be accepted when |
| * received from peer. */ |
| if (llme->old_tlli != 0xffffffff) { |
| llme->old_tlli = 0xffffffff; |
| llme->tlli = new_tlli; |
| } else { |
| /* If TLLI old == 0xffffffff was assigned to LLME, then this is |
| * TLLI assignmemt according to 8.3.1 */ |
| llme->old_tlli = 0xffffffff; |
| llme->tlli = new_tlli; |
| llme->state = GPRS_LLMS_ASSIGNED; |
| /* 8.5.3.1 For all LLE's */ |
| for (i = 0; i < ARRAY_SIZE(llme->lle); i++) { |
| struct gprs_llc_lle *l = &llme->lle[i]; |
| l->vu_send = l->vu_recv = 0; |
| l->retrans_ctr = 0; |
| l->state = GPRS_LLES_ASSIGNED_ADM; |
| /* FIXME Set parameters according to table 9 */ |
| } |
| } |
| } else if (old_tlli != 0xffffffff && new_tlli != 0xffffffff) { |
| /* TLLI Change 8.3.2 */ |
| /* Both TLLI Old and TLLI New are assigned; use New when |
| * (re)transmitting. Accept toth Old and New on Rx */ |
| llme->old_tlli = llme->tlli; |
| llme->tlli = new_tlli; |
| llme->state = GPRS_LLMS_ASSIGNED; |
| } else if (old_tlli != 0xffffffff && new_tlli == 0xffffffff) { |
| /* TLLI Unassignment 8.3.3) */ |
| llme->tlli = llme->old_tlli = 0; |
| llme->state = GPRS_LLMS_UNASSIGNED; |
| for (i = 0; i < ARRAY_SIZE(llme->lle); i++) { |
| struct gprs_llc_lle *l = &llme->lle[i]; |
| l->state = GPRS_LLES_UNASSIGNED; |
| } |
| llme_free(llme); |
| } else |
| return -EINVAL; |
| |
| return 0; |
| } |
| |
| int gprs_llc_init(const char *cipher_plugin_path) |
| { |
| return gprs_cipher_load(cipher_plugin_path); |
| } |