diff options
Diffstat (limited to 'src/mslookup_server.c')
| -rw-r--r-- | src/mslookup_server.c | 376 |
1 files changed, 376 insertions, 0 deletions
diff --git a/src/mslookup_server.c b/src/mslookup_server.c new file mode 100644 index 0000000..9c4dc58 --- /dev/null +++ b/src/mslookup_server.c @@ -0,0 +1,376 @@ +/* Copyright 2019 by sysmocom s.f.m.c. GmbH <info@sysmocom.de> + * + * 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 <string.h> +#include <errno.h> +#include <osmocom/core/sockaddr_str.h> +#include <osmocom/gsm/gsup.h> +#include <osmocom/mslookup/mslookup.h> +#include <osmocom/hlr/logging.h> +#include <osmocom/hlr/hlr.h> +#include <osmocom/hlr/db.h> +#include <osmocom/hlr/timestamp.h> +#include <osmocom/hlr/mslookup_server.h> + +static const struct osmo_mslookup_result not_found = { + .rc = OSMO_MSLOOKUP_RC_NOT_FOUND, + }; +const struct osmo_ipa_name mslookup_server_msc_wildcard = {}; + +static void set_result(struct osmo_mslookup_result *result, + const struct mslookup_service_host *service_host, + uint32_t age) +{ + if (!osmo_sockaddr_str_is_nonzero(&service_host->host_v4) + && !osmo_sockaddr_str_is_nonzero(&service_host->host_v6)) { + *result = not_found; + return; + } + result->rc = OSMO_MSLOOKUP_RC_RESULT; + result->host_v4 = service_host->host_v4; + result->host_v6 = service_host->host_v6; + result->age = age; +} + +const struct mslookup_service_host *mslookup_server_get_local_gsup_addr() +{ + static struct mslookup_service_host gsup_bind = {}; + struct mslookup_service_host *host; + + /* Find a HLR/GSUP service set for the server (no VLR unit name) */ + host = mslookup_server_service_get(&mslookup_server_msc_wildcard, OSMO_MSLOOKUP_SERVICE_HLR_GSUP); + if (host) + return host; + + /* Try to use the locally configured GSUP bind address */ + osmo_sockaddr_str_from_str(&gsup_bind.host_v4, g_hlr->gsup_bind_addr, OSMO_GSUP_PORT); + if (gsup_bind.host_v4.af == AF_INET6) { + gsup_bind.host_v6 = gsup_bind.host_v4; + gsup_bind.host_v4 = (struct osmo_sockaddr_str){}; + } + return &gsup_bind; +} + +struct mslookup_server_msc_cfg *mslookup_server_msc_get(const struct osmo_ipa_name *msc_name, bool create) +{ + struct llist_head *c = &g_hlr->mslookup.server.local_site_services; + struct mslookup_server_msc_cfg *msc; + + if (!msc_name) + return NULL; + + llist_for_each_entry(msc, c, entry) { + if (osmo_ipa_name_cmp(&msc->name, msc_name)) + continue; + return msc; + } + if (!create) + return NULL; + + msc = talloc_zero(g_hlr, struct mslookup_server_msc_cfg); + OSMO_ASSERT(msc); + INIT_LLIST_HEAD(&msc->service_hosts); + msc->name = *msc_name; + llist_add_tail(&msc->entry, c); + return msc; +} + +struct mslookup_service_host *mslookup_server_msc_service_get(struct mslookup_server_msc_cfg *msc, const char *service, + bool create) +{ + struct mslookup_service_host *e; + if (!msc) + return NULL; + + llist_for_each_entry(e, &msc->service_hosts, entry) { + if (!strcmp(e->service, service)) + return e; + } + + if (!create) + return NULL; + + e = talloc_zero(msc, struct mslookup_service_host); + OSMO_ASSERT(e); + OSMO_STRLCPY_ARRAY(e->service, service); + llist_add_tail(&e->entry, &msc->service_hosts); + return e; +} + +struct mslookup_service_host *mslookup_server_service_get(const struct osmo_ipa_name *msc_name, const char *service) +{ + struct mslookup_server_msc_cfg *msc = mslookup_server_msc_get(msc_name, false); + if (!msc) + return NULL; + return mslookup_server_msc_service_get(msc, service, false); +} + +int mslookup_server_msc_service_set(struct mslookup_server_msc_cfg *msc, const char *service, + const struct osmo_sockaddr_str *addr) +{ + struct mslookup_service_host *e; + + if (!service || !service[0] + || strlen(service) > OSMO_MSLOOKUP_SERVICE_MAXLEN) + return -EINVAL; + if (!addr || !osmo_sockaddr_str_is_nonzero(addr)) + return -EINVAL; + + e = mslookup_server_msc_service_get(msc, service, true); + if (!e) + return -EINVAL; + + switch (addr->af) { + case AF_INET: + e->host_v4 = *addr; + break; + case AF_INET6: + e->host_v6 = *addr; + break; + default: + return -EINVAL; + } + return 0; +} + +int mslookup_server_msc_service_del(struct mslookup_server_msc_cfg *msc, const char *service, + const struct osmo_sockaddr_str *addr) +{ + struct mslookup_service_host *e, *n; + int deleted = 0; + + if (!msc) + return -ENOENT; + + llist_for_each_entry_safe(e, n, &msc->service_hosts, entry) { + if (service && strcmp(service, e->service)) + continue; + + if (addr) { + if (!osmo_sockaddr_str_cmp(addr, &e->host_v4)) { + e->host_v4 = (struct osmo_sockaddr_str){}; + /* Removed one addr. If the other is still there, keep the entry. */ + if (osmo_sockaddr_str_is_nonzero(&e->host_v6)) + continue; + } else if (!osmo_sockaddr_str_cmp(addr, &e->host_v6)) { + e->host_v6 = (struct osmo_sockaddr_str){}; + /* Removed one addr. If the other is still there, keep the entry. */ + if (osmo_sockaddr_str_is_nonzero(&e->host_v4)) + continue; + } else + /* No addr match, keep the entry. */ + continue; + /* Addr matched and none is left. Delete. */ + } + llist_del(&e->entry); + talloc_free(e); + deleted++; + } + return deleted; +} + +/* A remote entity is asking us whether we are the home HLR of the given subscriber. */ +static void mslookup_server_rx_hlr_gsup(const struct osmo_mslookup_query *query, + struct osmo_mslookup_result *result) +{ + const struct mslookup_service_host *host; + int rc; + switch (query->id.type) { + case OSMO_MSLOOKUP_ID_IMSI: + rc = db_subscr_exists_by_imsi(g_hlr->dbc, query->id.imsi); + break; + case OSMO_MSLOOKUP_ID_MSISDN: + rc = db_subscr_exists_by_msisdn(g_hlr->dbc, query->id.msisdn); + break; + default: + LOGP(DMSLOOKUP, LOGL_ERROR, "Unknown mslookup ID type: %d\n", query->id.type); + *result = not_found; + return; + } + + if (rc) { + LOGP(DMSLOOKUP, LOGL_DEBUG, "%s: does not exist in local HLR\n", + osmo_mslookup_result_name_c(OTC_SELECT, query, NULL)); + *result = not_found; + return; + } + + LOGP(DMSLOOKUP, LOGL_DEBUG, "%s: found in local HLR\n", + osmo_mslookup_result_name_c(OTC_SELECT, query, NULL)); + + host = mslookup_server_get_local_gsup_addr(); + + set_result(result, host, 0); + if (result->rc != OSMO_MSLOOKUP_RC_RESULT) { + LOGP(DMSLOOKUP, LOGL_ERROR, + "Subscriber found, but error in service '" OSMO_MSLOOKUP_SERVICE_HLR_GSUP "' config:" + " v4: " OSMO_SOCKADDR_STR_FMT " v6: " OSMO_SOCKADDR_STR_FMT "\n", + OSMO_SOCKADDR_STR_FMT_ARGS(&host->host_v4), + OSMO_SOCKADDR_STR_FMT_ARGS(&host->host_v6)); + } +} + +/* Look in the local HLR record: If the subscriber is "at home" in this HLR and is also currently located at a local + * VLR, we will find a valid location updating with vlr_number, and no vlr_via_proxy entry. */ +static bool subscriber_has_done_lu_here_hlr(const struct osmo_mslookup_query *query, + uint32_t *lu_age, + struct osmo_ipa_name *local_msc_name, + struct hlr_subscriber *ret_subscr) +{ + struct hlr_subscriber _subscr; + int rc; + uint32_t age; + + struct hlr_subscriber *subscr = ret_subscr ? : &_subscr; + + switch (query->id.type) { + case OSMO_MSLOOKUP_ID_IMSI: + rc = db_subscr_get_by_imsi(g_hlr->dbc, query->id.imsi, subscr); + break; + case OSMO_MSLOOKUP_ID_MSISDN: + rc = db_subscr_get_by_msisdn(g_hlr->dbc, query->id.msisdn, subscr); + break; + default: + LOGP(DMSLOOKUP, LOGL_ERROR, "Unknown mslookup ID type: %d\n", query->id.type); + return false; + } + + if (rc) { + LOGP(DMSLOOKUP, LOGL_DEBUG, "%s: does not exist in local HLR\n", + osmo_mslookup_result_name_c(OTC_SELECT, query, NULL)); + return false; + } + + if (!subscr->vlr_number[0]) { + LOGP(DMSLOOKUP, LOGL_DEBUG, "%s: not attached (vlr_number unset)\n", + osmo_mslookup_result_name_c(OTC_SELECT, query, NULL)); + return false; + } + + if (subscr->vlr_via_proxy.len) { + /* The VLR is behind a proxy, the subscriber is not attached to a local VLR but a remote one. That + * remote proxy should instead respond to the service lookup request. */ + LOGP(DMSLOOKUP, LOGL_DEBUG, "%s: last attach is not at local VLR, but at VLR '%s' via proxy %s\n", + osmo_mslookup_result_name_c(OTC_SELECT, query, NULL), + subscr->vlr_number, + osmo_ipa_name_to_str(&subscr->vlr_via_proxy)); + return false; + } + + if (!timestamp_age(&subscr->last_lu_seen, &age)) { + LOGP(DMSLOOKUP, LOGL_DEBUG, "%s: Invalid last_lu_seen timestamp for subscriber\n", + osmo_mslookup_result_name_c(OTC_SELECT, query, NULL)); + return false; + } + if (age > g_hlr->mslookup.server.local_attach_max_age) { + LOGP(DMSLOOKUP, LOGL_DEBUG, "%s: last attach was here, but too long ago: %us > %us\n", + osmo_mslookup_result_name_c(OTC_SELECT, query, NULL), + age, g_hlr->mslookup.server.local_attach_max_age); + return false; + } + + *lu_age = age; + osmo_ipa_name_set_str(local_msc_name, subscr->vlr_number); + LOGP(DMSLOOKUP, LOGL_DEBUG, "%s: attached %u seconds ago at local VLR %s\n", + osmo_mslookup_result_name_c(OTC_SELECT, query, NULL), + age, osmo_ipa_name_to_str(local_msc_name)); + + return true; +} + +static bool subscriber_has_done_lu_here(const struct osmo_mslookup_query *query, + uint32_t *lu_age_p, + struct osmo_ipa_name *local_msc_name) +{ + bool attached_here; + uint32_t lu_age = 0; + struct osmo_ipa_name msc_name = {}; + + /* First ask the local HLR db, but if the local proxy record indicates a more recent LU, use that instead. + * For all usual cases, only one of these will reflect a LU, even if a subscriber had more than one home HLR: + * - if the subscriber is known here, we will never proxy. + * - if the subscriber is not known here, this local HLR db will never record a LU. + * However, if a subscriber was being proxied to a remote home HLR, and if then the subscriber was also added to + * the local HLR database, there might occur a situation where both reflect a LU. So, to be safe against all + * situations, compare the two entries. + */ + attached_here = subscriber_has_done_lu_here_hlr(query, &lu_age, &msc_name, NULL); + + /* Future: If proxy has a younger lu, replace. */ + + if (attached_here && !msc_name.len) { + LOGP(DMSLOOKUP, LOGL_ERROR, "%s: attached here, but no VLR name known\n", + osmo_mslookup_result_name_c(OTC_SELECT, query, NULL)); + return false; + } + + if (!attached_here) { + /* Already logged "not attached" for both local-db and proxy attach */ + return false; + } + + LOGP(DMSLOOKUP, LOGL_INFO, "%s: attached here, at VLR %s\n", + osmo_mslookup_result_name_c(OTC_SELECT, query, NULL), + osmo_ipa_name_to_str(&msc_name)); + *lu_age_p = lu_age; + *local_msc_name = msc_name; + return true; +} + +/* A remote entity is asking us whether we are providing the given service for the given subscriber. */ +void mslookup_server_rx(const struct osmo_mslookup_query *query, + struct osmo_mslookup_result *result) +{ + const struct mslookup_service_host *service_host; + uint32_t age; + struct osmo_ipa_name msc_name; + + /* A request for a home HLR: answer exactly if this is the subscriber's home HLR, i.e. the IMSI is listed in the + * HLR database. */ + if (strcmp(query->service, OSMO_MSLOOKUP_SERVICE_HLR_GSUP) == 0) + return mslookup_server_rx_hlr_gsup(query, result); + + /* All other service types: answer when the subscriber has done a LU that is either listed in the local HLR or + * in the GSUP proxy database: i.e. if the subscriber has done a Location Updating at an VLR belonging to this + * HLR. Respond with whichever services are configured in the osmo-hlr.cfg. */ + if (!subscriber_has_done_lu_here(query, &age, &msc_name)) { + *result = not_found; + return; + } + + /* We've detected a LU here. The VLR where the LU happened is stored in msc_unit_name, and the LU age is stored + * in 'age'. Figure out the address configured for that VLR and service name. */ + service_host = mslookup_server_service_get(&msc_name, query->service); + + if (!service_host) { + /* Find such service set globally (no VLR unit name) */ + service_host = mslookup_server_service_get(&mslookup_server_msc_wildcard, query->service); + } + + if (!service_host) { + LOGP(DMSLOOKUP, LOGL_ERROR, + "%s: subscriber found, but no service %s configured, cannot service lookup request\n", + osmo_mslookup_result_name_c(OTC_SELECT, query, NULL), + osmo_quote_str_c(OTC_SELECT, query->service, -1)); + *result = not_found; + return; + } + + set_result(result, service_host, age); +} |