diff options
Diffstat (limited to 'openbsc/src/gprs/oap_messages.c')
| -rw-r--r-- | openbsc/src/gprs/oap_messages.c | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/openbsc/src/gprs/oap_messages.c b/openbsc/src/gprs/oap_messages.c new file mode 100644 index 000000000..eb520532a --- /dev/null +++ b/openbsc/src/gprs/oap_messages.c @@ -0,0 +1,178 @@ +/* Osmocom Authentication Protocol message encoder/decoder */ + +/* (C) 2015 by Sysmocom s.f.m.c. GmbH + * All Rights Reserved + * + * Author: Neels Hofmeyr + * + * 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 <openbsc/oap_messages.h> + +#include <openbsc/debug.h> +#include <openbsc/gprs_utils.h> +#include <openbsc/utils.h> + +#include <osmocom/gsm/tlv.h> +#include <osmocom/core/msgb.h> + +#include <stdint.h> + + +int oap_decode(const uint8_t *const_data, size_t data_len, + struct oap_message *oap_msg) +{ + int rc; + uint8_t tag; + /* the shift/match functions expect non-const pointers, but we'll + * either copy the data or cast pointers back to const before returning + * them + */ + uint8_t *data = (uint8_t *)const_data; + uint8_t *value; + size_t value_len; + + memset(oap_msg, 0, sizeof(*oap_msg)); + + /* message type */ + rc = gprs_shift_v_fixed(&data, &data_len, 1, &value); + if (rc < 0) + return -GMM_CAUSE_INV_MAND_INFO; + oap_msg->message_type = decode_big_endian(value, 1); + + /* specific parts */ + while (data_len > 0) { + enum oap_iei iei; + + rc = gprs_shift_tlv(&data, &data_len, &tag, &value, &value_len); + if (rc < 0) + return -GMM_CAUSE_PROTO_ERR_UNSPEC; + + iei = tag; + + switch (iei) { + case OAP_CLIENT_ID_IE: + if (value_len != 2) { + LOGP(DGPRS, LOGL_NOTICE, + "OAP IE type client ID (%d) should be 2 octets, but has %d\n", + (int)iei, (int)value_len); + return -GMM_CAUSE_PROTO_ERR_UNSPEC; + } + + oap_msg->client_id = decode_big_endian(value, value_len); + + if (oap_msg->client_id == 0) { + LOGP(DGPRS, LOGL_NOTICE, + "OAP IE type client ID (%d): client ID must be nonzero.\n", + (int)iei); + return -GMM_CAUSE_PROTO_ERR_UNSPEC; + } + break; + + case OAP_AUTN_IE: + if (value_len != sizeof(oap_msg->autn)) { + LOGP(DGPRS, LOGL_NOTICE, + "OAP IE type AUTN (%d) should be %d octets, but has %d\n", + (int)iei, (int)sizeof(oap_msg->autn), (int)value_len); + return -GMM_CAUSE_PROTO_ERR_UNSPEC; + } + memcpy(oap_msg->autn, value, value_len); + oap_msg->autn_present = value_len; + break; + + case OAP_RAND_IE: + if (value_len != sizeof(oap_msg->rand)) { + LOGP(DGPRS, LOGL_NOTICE, + "OAP IE type RAND (%d) should be %d octets, but has %d\n", + (int)iei, (int)sizeof(oap_msg->rand), (int)value_len); + return -GMM_CAUSE_PROTO_ERR_UNSPEC; + } + memcpy(oap_msg->rand, value, value_len); + oap_msg->rand_present = value_len; + break; + + case OAP_XRES_IE: + if (value_len != sizeof(oap_msg->xres)) { + LOGP(DGPRS, LOGL_NOTICE, + "OAP IE type XRES (%d) should be %d octets, but has %d\n", + (int)iei, (int)sizeof(oap_msg->xres), (int)value_len); + return -GMM_CAUSE_PROTO_ERR_UNSPEC; + } + memcpy(oap_msg->xres, value, value_len); + oap_msg->xres_present = value_len; + break; + + case OAP_AUTS_IE: + if (value_len != sizeof(oap_msg->auts)) { + LOGP(DGPRS, LOGL_NOTICE, + "OAP IE type AUTS (%d) should be %d octets, but has %d\n", + (int)iei, (int)sizeof(oap_msg->auts), (int)value_len); + return -GMM_CAUSE_PROTO_ERR_UNSPEC; + } + memcpy(oap_msg->auts, value, value_len); + oap_msg->auts_present = value_len; + break; + + case OAP_CAUSE_IE: + if (value_len > 1) { + LOGP(DGPRS, LOGL_ERROR, + "OAP cause may not exceed one octet, is %d", (int)value_len); + return -GMM_CAUSE_PROTO_ERR_UNSPEC; + } + oap_msg->cause = *value; + break; + + default: + LOGP(DGPRS, LOGL_NOTICE, + "OAP IE type %d unknown\n", iei); + continue; + } + } + + return 0; +} + +void oap_encode(struct msgb *msg, const struct oap_message *oap_msg) +{ + uint8_t u8; + + /* generic part */ + OSMO_ASSERT(oap_msg->message_type); + msgb_v_put(msg, (uint8_t)oap_msg->message_type); + + /* specific parts */ + if ((u8 = oap_msg->cause)) + msgb_tlv_put(msg, OAP_CAUSE_IE, sizeof(u8), &u8); + + if (oap_msg->client_id > 0) + msgb_tlv_put(msg, OAP_CLIENT_ID_IE, sizeof(oap_msg->client_id), + encode_big_endian(oap_msg->client_id, sizeof(oap_msg->client_id))); + + if (oap_msg->rand_present) + msgb_tlv_put(msg, OAP_RAND_IE, sizeof(oap_msg->rand), oap_msg->rand); + + if (oap_msg->autn_present) + msgb_tlv_put(msg, OAP_AUTN_IE, sizeof(oap_msg->autn), oap_msg->autn); + + if (oap_msg->auts_present) + msgb_tlv_put(msg, OAP_AUTS_IE, sizeof(oap_msg->auts), oap_msg->auts); + + if (oap_msg->xres_present) + msgb_tlv_put(msg, OAP_XRES_IE, sizeof(oap_msg->xres), oap_msg->xres); + + msg->l2h = msg->data; +} + |