Review at https://gerrit.osmocom.org/5698
Implement support for paging by LAI. Also, parse the complete cell identifier list for both LAC and LAI. Change-Id: Ic3c62ff0fccea586794ea4b3c275a0685cc9326e Related: OS#2751 --- M src/osmo-bsc/osmo_bsc_bssap.c M tests/bssap/bssap_test.c 2 files changed, 109 insertions(+), 46 deletions(-) git pull ssh://gerrit.osmocom.org:29418/osmo-bsc refs/changes/98/5698/1 diff --git a/src/osmo-bsc/osmo_bsc_bssap.c b/src/osmo-bsc/osmo_bsc_bssap.c index 0ecc11c..83acbb2 100644 --- a/src/osmo-bsc/osmo_bsc_bssap.c +++ b/src/osmo-bsc/osmo_bsc_bssap.c @@ -228,21 +228,52 @@ return 0; } +/* Page a subscriber based on TMSI and LAC. + * A non-zero return value indicates a fatal out of memory condition. */ +static int +page_subscriber(struct bsc_msc_data *msc, uint16_t tmsi, uint32_t lac, + const char *mi_string, uint8_t chan_needed) +{ + struct bsc_subscr *subscr; + + subscr = bsc_subscr_find_or_create_by_imsi(msc->network->bsc_subscribers, + mi_string); + if (!subscr) { + LOGP(DMSC, LOGL_ERROR, "Failed to allocate a subscriber for %s\n", mi_string); + return -1; + } + + subscr->lac = lac; + subscr->tmsi = tmsi; + + LOGP(DMSC, LOGL_INFO, "Paging request from MSC IMSI: '%s' TMSI: '0x%x/%u' LAC: 0x%x\n", mi_string, tmsi, tmsi, lac); + bsc_grace_paging_request(msc->network->bsc_data->rf_ctrl->policy, + subscr, chan_needed, msc); + + /* the paging code has grabbed its own references */ + bsc_subscr_put(subscr); + + return 0; +} + /* GSM 08.08 ยง 3.2.1.19 */ static int bssmap_handle_paging(struct bsc_msc_data *msc, struct msgb *msg, unsigned int payload_length) { - struct bsc_subscr *subscr; struct tlv_parsed tp; char mi_string[GSM48_MI_SIZE]; uint32_t tmsi = GSM_RESERVED_TMSI; - unsigned int lac; + uint16_t lac, *lacp_be; + uint16_t mcc; + uint16_t mnc; uint8_t data_length; + int remain; const uint8_t *data; uint8_t chan_needed = RSL_CHANNEED_ANY; uint8_t cell_ident; tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l4h + 1, payload_length - 1, 0, 0); + remain = payload_length - 1; if (!TLVP_PRESENT(&tp, GSM0808_IE_IMSI)) { LOGP(DMSC, LOGL_ERROR, "Mandatory IMSI not present.\n"); @@ -251,6 +282,7 @@ LOGP(DMSC, LOGL_ERROR, "Wrong content in the IMSI\n"); return -1; } + remain -= TLVP_LEN(&tp, GSM0808_IE_IMSI); if (!TLVP_PRESENT(&tp, GSM0808_IE_CELL_IDENTIFIER_LIST)) { LOGP(DMSC, LOGL_ERROR, "Mandatory CELL IDENTIFIER LIST not present.\n"); @@ -260,6 +292,12 @@ if (TLVP_PRESENT(&tp, GSM0808_IE_TMSI) && TLVP_LEN(&tp, GSM0808_IE_TMSI) == 4) { tmsi = ntohl(tlvp_val32_unal(&tp, GSM0808_IE_TMSI)); + remain -= TLVP_LEN(&tp, GSM0808_IE_TMSI); + } + + if (remain <= 0) { + LOGP(DMSC, LOGL_ERROR, "Payload too short.\n"); + return -1; } /* @@ -280,38 +318,12 @@ LOGP(DMSC, LOGL_ERROR, "Paging IMSI %s: Zero length Cell Identifier List\n", mi_string); return -1; + } else if (data_length > remain) { + LOGP(DMSC, LOGL_ERROR, "Paging IMSI %s: Bogus Cell Identifier List length\n", + mi_string); + return -1; } - - cell_ident = data[0] & 0xf; - - /* Default fallback: page entire BSS */ - lac = GSM_LAC_RESERVED_ALL_BTS; - - switch (cell_ident) { - case CELL_IDENT_LAC: - if (data_length != 3) { - LOGP(DMSC, LOGL_ERROR, "Paging IMSI %s: Cell Identifier List for LAC (0x%x)" - " has invalid length: %u, paging entire BSS instead (%s)\n", - mi_string, CELL_IDENT_LAC, data_length, osmo_hexdump(data, data_length)); - break; - } - lac = osmo_load16be(&data[1]); - break; - - case CELL_IDENT_BSS: - if (data_length != 1) { - LOGP(DMSC, LOGL_ERROR, "Paging IMSI %s: Cell Identifier List for BSS (0x%x)" - " has invalid length: %u, paging entire BSS anyway (%s)\n", - mi_string, CELL_IDENT_BSS, data_length, osmo_hexdump(data, data_length)); - } - break; - - default: - LOGP(DMSC, LOGL_NOTICE, "Paging IMSI %s: unimplemented Cell Identifier List (0x%x)," - " paging entire BSS instead (%s)\n", - mi_string, cell_ident, osmo_hexdump(data, data_length)); - break; - } + remain = data_length; /* ignore payload padding data beyond data_length */ if (TLVP_PRESENT(&tp, GSM0808_IE_CHANNEL_NEEDED) && TLVP_LEN(&tp, GSM0808_IE_CHANNEL_NEEDED) == 1) chan_needed = TLVP_VAL(&tp, GSM0808_IE_CHANNEL_NEEDED)[0] & 0x03; @@ -320,22 +332,73 @@ LOGP(DMSC, LOGL_ERROR, "eMLPP is not handled\n"); } - subscr = bsc_subscr_find_or_create_by_imsi(msc->network->bsc_subscribers, - mi_string); - if (!subscr) { - LOGP(DMSC, LOGL_ERROR, "Failed to allocate a subscriber for %s\n", mi_string); - return -1; + cell_ident = data[0] & 0xf; + remain -= 1; /* cell ident consumed */ + + /* Default fallback: page entire BSS */ + lac = GSM_LAC_RESERVED_ALL_BTS; + + switch (cell_ident) { + case CELL_IDENT_LAI_AND_LAC: { + struct gsm48_loc_area_id lai; + int i = 0; + while (remain >= sizeof(lai)) { + /* Parse and decode 5-byte LAI list element (see TS 08.08 3.2.2.27). + * Copy data to stack to prevent unaligned access in gsm48_decode_lai(). */ + lai.digits[0] = data[1 + i * sizeof(lai)]; + lai.digits[1] = data[2 + i * sizeof(lai)]; + lai.digits[2] = data[3 + i * sizeof(lai)]; + memcpy(&lai.lac, &data[4 + i * sizeof(lai)], sizeof(lai.lac)); /* don't byte-swap yet */ + if (gsm48_decode_lai(&lai, &mcc, &mnc, &lac) != 0) { + LOGP(DMSC, LOGL_ERROR, "Paging IMSI %s: Invalid LAI in Cell Identifier List " + "for BSS (0x%x), paging entire BSS anyway (%s)\n", + mi_string, CELL_IDENT_BSS, osmo_hexdump(data, data_length)); + lac = GSM_LAC_RESERVED_ALL_BTS; + break; + } + if (mcc == msc->network->country_code && mnc == msc->network->network_code) { + if (page_subscriber(msc, tmsi, lac, mi_string, chan_needed) != 0) + break; + } else + LOGP(DMSC, LOGL_DEBUG, "Not paging IMSI %s: MCC/MNC in Cell Identifier List " + "(%d/%d) do not match our network (%d/%d)\n", mi_string, mcc, mnc, + msc->network->country_code, msc->network->network_code); + + remain -= sizeof(lai); + i++; + } + break; } - subscr->lac = lac; - subscr->tmsi = tmsi; + case CELL_IDENT_LAC: + lacp_be = (uint16_t *)(&data[1]); + while (remain >= sizeof(*lacp_be)) { + lac = osmo_load16be(lacp_be); + if (page_subscriber(msc, tmsi, lac, mi_string, chan_needed) != 0) + break; + remain -= sizeof(*lacp_be); + lacp_be++; + } + break; - LOGP(DMSC, LOGL_INFO, "Paging request from MSC IMSI: '%s' TMSI: '0x%x/%u' LAC: 0x%x\n", mi_string, tmsi, tmsi, lac); - bsc_grace_paging_request(msc->network->bsc_data->rf_ctrl->policy, - subscr, chan_needed, msc); + case CELL_IDENT_BSS: + if (data_length != 1) { + LOGP(DMSC, LOGL_ERROR, "Paging IMSI %s: Cell Identifier List for BSS (0x%x)" + " has invalid length: %u, paging entire BSS anyway (%s)\n", + mi_string, CELL_IDENT_BSS, data_length, osmo_hexdump(data, data_length)); + } + if (page_subscriber(msc, tmsi, GSM_LAC_RESERVED_ALL_BTS, mi_string, chan_needed) != 0) + break; + break; - /* the paging code has grabbed its own references */ - bsc_subscr_put(subscr); + default: + LOGP(DMSC, LOGL_NOTICE, "Paging IMSI %s: unimplemented Cell Identifier List (0x%x)," + " paging entire BSS instead (%s)\n", + mi_string, cell_ident, osmo_hexdump(data, data_length)); + if (page_subscriber(msc, tmsi, GSM_LAC_RESERVED_ALL_BTS, mi_string, chan_needed) != 0) + break; + break; + } return 0; } diff --git a/tests/bssap/bssap_test.c b/tests/bssap/bssap_test.c index 579cae2..2fa2b1f 100644 --- a/tests/bssap/bssap_test.c +++ b/tests/bssap/bssap_test.c @@ -71,7 +71,7 @@ { "001952080859512069000743940904010844601a060415f5490065", /* ^^^^^^^^^^^^ Cell Identifier List: LAI */ - GSM_LAC_RESERVED_ALL_BTS, 0 + 0x65, 0 }, }; -- To view, visit https://gerrit.osmocom.org/5698 To unsubscribe, visit https://gerrit.osmocom.org/settings Gerrit-MessageType: newchange Gerrit-Change-Id: Ic3c62ff0fccea586794ea4b3c275a0685cc9326e Gerrit-PatchSet: 1 Gerrit-Project: osmo-bsc Gerrit-Branch: master Gerrit-Owner: Stefan Sperling <ssperl...@sysmocom.de>