diff options
Diffstat (limited to 'src/common/msg_utils.c')
| -rw-r--r-- | src/common/msg_utils.c | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/src/common/msg_utils.c b/src/common/msg_utils.c new file mode 100644 index 00000000..2d5ebd9b --- /dev/null +++ b/src/common/msg_utils.c @@ -0,0 +1,174 @@ +/* (C) 2014 by sysmocom s.f.m.c. GmbH + * + * 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 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 <osmo-bts/msg_utils.h> +#include <osmo-bts/logging.h> +#include <osmo-bts/oml.h> + +#include <osmocom/gsm/protocol/ipaccess.h> +#include <osmocom/gsm/protocol/gsm_12_21.h> +#include <osmocom/core/msgb.h> + +#include <arpa/inet.h> + + +static int check_fom(struct abis_om_hdr *omh, size_t len) +{ + if (omh->length != len) { + LOGP(DL1C, LOGL_ERROR, "Incorrect OM hdr length value %d %zu\n", + omh->length, len); + return -1; + } + + if (len < sizeof(struct abis_om_fom_hdr)) { + LOGP(DL1C, LOGL_ERROR, "FOM header insufficient space %zu %zu\n", + len, sizeof(struct abis_om_fom_hdr)); + return -1; + } + + return 0; +} + +static int check_manuf(struct msgb *msg, struct abis_om_hdr *omh, size_t msg_size) +{ + int type; + size_t size; + + if (msg_size < 1) { + LOGP(DL1C, LOGL_ERROR, "No ManId Length Indicator %zu\n", + msg_size); + return -1; + } + + if (omh->data[0] >= msg_size - 1) { + LOGP(DL1C, LOGL_ERROR, + "Insufficient message space for this ManId Length %d %zu\n", + omh->data[0], msg_size - 1); + return -1; + } + + if (omh->data[0] == sizeof(oml_ipa_magic) && + strncmp(oml_ipa_magic, (const char *)omh->data + 1, + sizeof(oml_ipa_magic)) == 0) { + type = OML_MSG_TYPE_IPA; + size = sizeof(oml_ipa_magic) + 1; + } else if (omh->data[0] == sizeof(oml_osmo_magic) && + strncmp(oml_osmo_magic, (const char *) omh->data + 1, + sizeof(oml_osmo_magic)) == 0) { + type = OML_MSG_TYPE_OSMO; + size = sizeof(oml_osmo_magic) + 1; + } else { + LOGP(DL1C, LOGL_ERROR, "Manuf Label Unknown\n"); + return -1; + } + + /* we have verified that the vendor string fits */ + msg->l3h = omh->data + size; + if (check_fom(omh, msgb_l3len(msg)) != 0) + return -1; + return type; +} + +/** + * Return 0 in case the IPA structure is okay and in this + * case the l2h will be set to the beginning of the data. + */ +int msg_verify_ipa_structure(struct msgb *msg) +{ + struct ipaccess_head *hh; + + if (msgb_l1len(msg) < sizeof(struct ipaccess_head)) { + LOGP(DL1C, LOGL_ERROR, + "Ipa header insufficient space %d %d\n", + msgb_l1len(msg), sizeof(struct ipaccess_head)); + return -1; + } + + hh = (struct ipaccess_head *) msg->l1h; + + if (hh->proto != IPAC_PROTO_OML) { + LOGP(DL1C, LOGL_ERROR, + "Incorrect ipa header protocol 0x%x 0x%x\n", + hh->proto, IPAC_PROTO_OML); + return -1; + } + + if (ntohs(hh->len) != msgb_l1len(msg) - sizeof(struct ipaccess_head)) { + LOGP(DL1C, LOGL_ERROR, + "Incorrect ipa header msg size %d %d\n", + ntohs(hh->len), msgb_l1len(msg) - sizeof(struct ipaccess_head)); + return -1; + } + + msg->l2h = hh->data; + return 0; +} + +/** + * \brief Verify the structure of the OML message and set l3h + * + * This function verifies that the data in \param in msg is a proper + * OML message. This code assumes that msg->l2h points to the + * beginning of the OML message. In the successful case the msg->l3h + * will be set and will point to the FOM header. The value is undefined + * in all other cases. + * + * \param msg The message to analyze starting from msg->l2h. + * \return In case the structure is correct a positive number will be + * returned and msg->l3h will point to the FOM. The number is a + * classification of the vendor type of the message. + */ +int msg_verify_oml_structure(struct msgb *msg) +{ + struct abis_om_hdr *omh; + + if (msgb_l2len(msg) < sizeof(*omh)) { + LOGP(DL1C, LOGL_ERROR, "Om header insufficient space %d %d\n", + msgb_l2len(msg), sizeof(*omh)); + return -1; + } + + omh = (struct abis_om_hdr *) msg->l2h; + if (omh->mdisc != ABIS_OM_MDISC_FOM && + omh->mdisc != ABIS_OM_MDISC_MANUF) { + LOGP(DL1C, LOGL_ERROR, "Incorrect om mdisc value %x\n", + omh->mdisc); + return -1; + } + + if (omh->placement != ABIS_OM_PLACEMENT_ONLY) { + LOGP(DL1C, LOGL_ERROR, "Incorrect om placement value %x %x\n", + omh->placement, ABIS_OM_PLACEMENT_ONLY); + return -1; + } + + if (omh->sequence != 0) { + LOGP(DL1C, LOGL_ERROR, "Incorrect om sequence value %d\n", + omh->sequence); + return -1; + } + + if (omh->mdisc == ABIS_OM_MDISC_MANUF) + return check_manuf(msg, omh, msgb_l2len(msg) - sizeof(*omh)); + + msg->l3h = omh->data; + if (check_fom(omh, msgb_l3len(msg)) != 0) + return -1; + return OML_MSG_TYPE_ETSI; +} |