| /* 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 <osmocom/core/utils.h> |
| #include <openbsc/oap_messages.h> |
| |
| #include <openbsc/debug.h> |
| |
| #include <osmocom/gsm/tlv.h> |
| #include <osmocom/core/msgb.h> |
| |
| #include <stdint.h> |
| |
| |
| int osmo_oap_decode(struct osmo_oap_message *oap_msg, |
| const uint8_t *const_data, size_t data_len) |
| { |
| 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 = osmo_shift_v_fixed(&data, &data_len, 1, &value); |
| if (rc < 0) |
| return -GMM_CAUSE_INV_MAND_INFO; |
| oap_msg->message_type = osmo_decode_big_endian(value, 1); |
| |
| /* specific parts */ |
| while (data_len > 0) { |
| enum oap_iei iei; |
| |
| rc = osmo_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 = osmo_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 osmo_oap_encode(struct msgb *msg, const struct osmo_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), |
| osmo_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; |
| } |
| |