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osmo-hlr/src/mslookup/mslookup.c

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/* 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 General Public License as published by
* the Free Software Foundation; either version 2 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 General Public License along
* with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <string.h>
#include <errno.h>
#include <osmocom/gsm/gsm23003.h>
#include <osmocom/mslookup/mslookup.h>
/*! \addtogroup mslookup
*
* Distributed GSM: finding subscribers
*
* There are various aspects of the D-GSM code base in osmo-hlr.git, here is an overview:
*
* mslookup is the main enabler of D-GSM, a concept for connecting services between independent core network stacks.
*
* D-GSM consists of:
* (1) mslookup client to find subscribers:
* (a) external clients like ESME, SIP PBX, ... ask osmo-hlr to tell where to send SMS, voice calls, ...
* (b) osmo-hlr's own mslookup client asks remote osmo-hlrs whether they know a given IMSI.
* (2) when a subscriber was found at a remote HLR, GSUP gets forwarded there:
* (a) to deliver messages for the GSUP proxy, osmo-hlr manages many GSUP clients to establish links to remote HLRs.
* (b) osmo-hlr has a GSUP proxy layer that caches data of IMSIs that get proxied to a remote HLR.
* (c) decision making to distinguish local IMSIs from ones proxied to a remote HLR.
*
* (1) mslookup is a method of finding subscribers using (multicast) queries, by MSISDN or by IMSI.
* It is open to various lookup methods, the first one being multicast DNS.
* An mslookup client sends a request, and an mslookup server responds.
* The mslookup server is implemented by osmo-hlr. mslookup clients are arbitrary programs, like an ESME or a SIP PBX.
* Hence the mslookup client is public API, while the mslookup server is implemented "privately" in osmo-hlr.
*
* (1a) Public mslookup client: libosmo-mslookup
* src/mslookup/mslookup.c Things useful for both client and server.
* src/mslookup/mslookup_client.c The client API, which can use various lookup methods,
* and consolidates results from various responders.
* src/mslookup/mslookup_client_mdns.c lookup method implementing multicast DNS, client side.
*
* src/mslookup/osmo-mslookup-client.c Utility program to ease invocation for (blocking) mslookup clients.
*
* src/mslookup/mslookup_client_fake.c lookup method generating fake results, for testing client implementations.
*
* src/mslookup/mdns*.c implementation of DNS to be used by mslookup_client_mdns.c,
* and the mslookup_server.c.
*
* contrib/dgsm/esme_dgsm.py Example implementation for an mslookup enabled SMS handler.
* contrib/dgsm/freeswitch_dialplan_dgsm.py Example implementation for an mslookup enabled FreeSWITCH dialplan.
* contrib/dgsm/osmo-mslookup-pipe.py Example for writing a python client using the osmo-mslookup-client
* cmdline.
* contrib/dgsm/osmo-mslookup-socket.py Example for writing a python client using the osmo-mslookup-client
* unix domain socket.
*
* (1b) "Private" mslookup server in osmo-hlr:
* src/mslookup_server.c Respond to mslookup queries, independent from the particular lookup method.
* src/mslookup_server_mdns.c mDNS specific implementation for mslookup_server.c.
* src/dgsm_vty.c Configure services that mslookup server sends to remote requests.
*
* (2) Proxy and GSUP clients to remote HLR instances:
*
* (a) Be a GSUP client to forward to a remote HLR:
* src/gsupclient/ The same API that is used by osmo-{msc,sgsn} is also used to forward GSUP to remote osmo-hlrs.
* src/remote_hlr.c Establish links to remote osmo-hlrs, where this osmo-hlr is a client (proxying e.g. for an MSC).
*
* (b) Keep track of remotely handled IMSIs:
* src/proxy.c Keep track of proxied IMSIs and cache important subscriber data.
*
* (c) Direct GSUP request to the right destination: either the local or a remote HLR:
* src/dgsm.c The glue that makes osmo-hlr distinguish between local IMSIs and those that are proxied to another
* osmo-hlr.
* src/dgsm_vty.c Config.
*
* @{
* \file mslookup.c
*/
const struct value_string osmo_mslookup_id_type_names[] = {
{ OSMO_MSLOOKUP_ID_NONE, "none" },
{ OSMO_MSLOOKUP_ID_IMSI, "imsi" },
{ OSMO_MSLOOKUP_ID_MSISDN, "msisdn" },
{}
};
const struct value_string osmo_mslookup_result_code_names[] = {
{ OSMO_MSLOOKUP_RC_NONE, "none" },
{ OSMO_MSLOOKUP_RC_RESULT, "result" },
{ OSMO_MSLOOKUP_RC_NOT_FOUND, "not-found" },
{}
};
/*! Compare two struct osmo_mslookup_id.
* \returns 0 if a and b are equal,
* < 0 if a (or the ID type / start of ID) is < b,
* > 0 if a (or the ID type / start of ID) is > b.
*/
int osmo_mslookup_id_cmp(const struct osmo_mslookup_id *a, const struct osmo_mslookup_id *b)
{
int cmp;
if (a == b)
return 0;
if (!a)
return -1;
if (!b)
return 1;
cmp = OSMO_CMP(a->type, b->type);
if (cmp)
return cmp;
switch (a->type) {
case OSMO_MSLOOKUP_ID_IMSI:
return strncmp(a->imsi, b->imsi, sizeof(a->imsi));
case OSMO_MSLOOKUP_ID_MSISDN:
return strncmp(a->msisdn, b->msisdn, sizeof(a->msisdn));
default:
return 0;
}
}
bool osmo_mslookup_id_valid(const struct osmo_mslookup_id *id)
{
switch (id->type) {
case OSMO_MSLOOKUP_ID_IMSI:
return osmo_imsi_str_valid(id->imsi);
case OSMO_MSLOOKUP_ID_MSISDN:
return osmo_msisdn_str_valid(id->msisdn);
default:
return false;
}
}
bool osmo_mslookup_service_valid(const char *service)
{
return strlen(service) > 0;
}
/*! Write ID and ID type to a buffer.
* \param[out] buf nul-terminated {id}.{id_type} string (e.g. "1234.msisdn") or
* "?.none" if the ID type is invalid.
* \returns amount of bytes written to buf.
*/
size_t osmo_mslookup_id_name_buf(char *buf, size_t buflen, const struct osmo_mslookup_id *id)
{
struct osmo_strbuf sb = { .buf = buf, .len = buflen };
switch (id->type) {
case OSMO_MSLOOKUP_ID_IMSI:
OSMO_STRBUF_PRINTF(sb, "%s", id->imsi);
break;
case OSMO_MSLOOKUP_ID_MSISDN:
OSMO_STRBUF_PRINTF(sb, "%s", id->msisdn);
break;
default:
OSMO_STRBUF_PRINTF(sb, "?");
break;
}
OSMO_STRBUF_PRINTF(sb, ".%s", osmo_mslookup_id_type_name(id->type));
return sb.chars_needed;
}
/*! Same as osmo_mslookup_id_name_buf(), but return a talloc allocated string of sufficient size. */
char *osmo_mslookup_id_name_c(void *ctx, const struct osmo_mslookup_id *id)
{
OSMO_NAME_C_IMPL(ctx, 64, "ERROR", osmo_mslookup_id_name_buf, id)
}
/*! Same as osmo_mslookup_id_name_buf(), but directly return the char* (for printf-like string formats). */
char *osmo_mslookup_id_name_b(char *buf, size_t buflen, const struct osmo_mslookup_id *id)
{
int rc = osmo_mslookup_id_name_buf(buf, buflen, id);
if (rc < 0 && buflen)
buf[0] = '\0';
return buf;
}
/*! Write mslookup result string to buffer.
* \param[in] query with the service, ID and ID type to be written to buf like a domain string, or NULL to omit.
* \param[in] result with the result code, IPv4/v6 and age to be written to buf or NULL to omit.
* \param[out] buf result as flat string, which looks like the following for a valid query and result with IPv4 and v6
* answer: "sip.voice.1234.msisdn -> ipv4: 42.42.42.42:1337 -> ipv6: [1234:5678:9ABC::]:1338 (age=1)",
* the result part can also be " -> timeout" or " -> rc=5" depending on the result code.
* \returns amount of bytes written to buf.
*/
size_t osmo_mslookup_result_to_str_buf(char *buf, size_t buflen,
const struct osmo_mslookup_query *query,
const struct osmo_mslookup_result *result)
{
struct osmo_strbuf sb = { .buf = buf, .len = buflen };
if (query) {
OSMO_STRBUF_PRINTF(sb, "%s.", query->service);
OSMO_STRBUF_APPEND(sb, osmo_mslookup_id_name_buf, &query->id);
}
if (result && result->rc == OSMO_MSLOOKUP_RC_NONE)
result = NULL;
if (result) {
if (result->rc != OSMO_MSLOOKUP_RC_RESULT) {
OSMO_STRBUF_PRINTF(sb, " %s", osmo_mslookup_result_code_name(result->rc));
} else {
if (result->host_v4.ip[0]) {
OSMO_STRBUF_PRINTF(sb, " -> ipv4: " OSMO_SOCKADDR_STR_FMT,
OSMO_SOCKADDR_STR_FMT_ARGS(&result->host_v4));
}
if (result->host_v6.ip[0]) {
OSMO_STRBUF_PRINTF(sb, " -> ipv6: " OSMO_SOCKADDR_STR_FMT,
OSMO_SOCKADDR_STR_FMT_ARGS(&result->host_v6));
}
OSMO_STRBUF_PRINTF(sb, " (age=%u)", result->age);
}
OSMO_STRBUF_PRINTF(sb, " %s", result->last ? "(last)" : "(not-last)");
}
return sb.chars_needed;
}
/*! Same as osmo_mslookup_result_to_str_buf(), but return a talloc allocated string of sufficient size. */
char *osmo_mslookup_result_name_c(void *ctx,
const struct osmo_mslookup_query *query,
const struct osmo_mslookup_result *result)
{
OSMO_NAME_C_IMPL(ctx, 64, "ERROR", osmo_mslookup_result_to_str_buf, query, result)
}
/*! Same as osmo_mslookup_result_to_str_buf(), but directly return the char* (for printf-like string formats). */
char *osmo_mslookup_result_name_b(char *buf, size_t buflen,
const struct osmo_mslookup_query *query,
const struct osmo_mslookup_result *result)
{
int rc = osmo_mslookup_result_to_str_buf(buf, buflen, query, result);
if (rc < 0 && buflen)
buf[0] = '\0';
return buf;
}
/*! Copy part of a string to a buffer and nul-terminate it.
* \returns 0 on success, negative on error.
*/
static int token(char *dest, size_t dest_size, const char *start, const char *end)
{
int len;
if (start >= end)
return -10;
len = end - start;
if (len >= dest_size)
return -11;
strncpy(dest, start, len);
dest[len] = '\0';
return 0;
}
/*! Parse a string like "foo.moo.goo.123456789012345.msisdn" into service="foo.moo.goo", id="123456789012345" and
* id_type="msisdn", placed in a struct osmo_mslookup_query.
* \param q Write parsed query to this osmo_mslookup_query.
* \param domain Human readable domain string like "sip.voice.12345678.msisdn".
* \returns 0 on success, negative on error.
*/
int osmo_mslookup_query_init_from_domain_str(struct osmo_mslookup_query *q, const char *domain)
{
const char *last_dot;
const char *second_last_dot;
const char *id_type;
const char *id;
int rc;
*q = (struct osmo_mslookup_query){};
if (!domain)
return -1;
last_dot = strrchr(domain, '.');
if (!last_dot)
return -2;
if (last_dot <= domain)
return -3;
for (second_last_dot = last_dot - 1; second_last_dot > domain && *second_last_dot != '.'; second_last_dot--);
if (second_last_dot == domain || *second_last_dot != '.')
return -3;
id_type = last_dot + 1;
if (!*id_type)
return -4;
q->id.type = get_string_value(osmo_mslookup_id_type_names, id_type);
id = second_last_dot + 1;
switch (q->id.type) {
case OSMO_MSLOOKUP_ID_IMSI:
rc = token(q->id.imsi, sizeof(q->id.imsi), id, last_dot);
if (rc)
return rc;
if (!osmo_imsi_str_valid(q->id.imsi))
return -5;
break;
case OSMO_MSLOOKUP_ID_MSISDN:
rc = token(q->id.msisdn, sizeof(q->id.msisdn), id, last_dot);
if (rc)
return rc;
if (!osmo_msisdn_str_valid(q->id.msisdn))
return -6;
break;
default:
return -7;
}
return token(q->service, sizeof(q->service), domain, second_last_dot);
}
/*! @} */
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