1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
|
/*
* SCCPlite MGCP handling
*
* (C) 2018 by Harald Welte <laforge@gnumonks.org>
* (C) 2023 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 <osmocom/core/utils.h>
#include <osmocom/core/msgb.h>
#include <osmocom/core/socket.h>
#include <osmocom/core/sockaddr_str.h>
#include <osmocom/mgcp_client/mgcp_client_endpoint_fsm.h>
#include <osmocom/mgcp_client/mgcp_client.h>
#include <osmocom/bsc/bsc_msc_data.h>
#include <osmocom/bsc/osmo_bsc.h>
#include <osmocom/bsc/gsm_data.h>
#include <osmocom/bsc/debug.h>
#include <osmocom/gsm/ipa.h>
#include <osmocom/gsm/protocol/ipaccess.h>
#include <osmocom/bsc/osmo_bsc_sigtran.h>
#include <arpa/inet.h>
/* Determine MSC based on the ASP over which the message was received */
static struct bsc_msc_data *msc_from_asp(struct osmo_ss7_asp *asp)
{
int msc_nr;
const char *asp_name = osmo_ss7_asp_get_name(asp);
/* this is rather ugly, as we of course have MTP-level routing between
* the local SCCP user (BSC) and the AS/ASPs. However, for the most simple
* SCCPlite case, there is a 1:1 mapping between ASP and AS, and using
* the libosmo-sigtran "simple client", the names are "as[p]-clnt-msc-%u",
* as set in osmo_bsc_sigtran_init() */
if (!asp_name || sscanf(asp_name, "asp-clnt-msc-%u", &msc_nr) != 1) {
LOGP(DMSC, LOGL_ERROR, "Cannot find to which MSC the ASP '%s' belongs\n", asp_name);
return NULL;
}
return osmo_msc_data_find(bsc_gsmnet, msc_nr);
}
/* negative on error, zero upon success */
static int parse_local_endpoint_name(char *buf, size_t buf_len, const char *data)
{
char line[1024];
char *epstart, *sep;
const char *start = data;
char *eol = strpbrk(start, "\r\n");
if (!eol)
return -1;
if (eol - start > sizeof(line))
return -1;
memcpy(line, start, eol - start);
line[eol - start] = '\0';
if (!(epstart = strchr(line, ' ')))
return -1;
epstart++;
/* epstart now points to trans */
if (!(epstart = strchr(epstart, ' ')))
return -1;
epstart++;
/* epstart now points to endpoint */
if (!(sep = strchr(epstart, '@')))
return -1;
if (sep - epstart >= buf_len)
return -1;
*sep = '\0';
osmo_strlcpy(buf, epstart, buf_len);
return 0;
}
/* We received an IPA-encapsulated MGCP message from a MSC. Transfers msg ownership. */
int bsc_sccplite_rx_mgcp(struct osmo_ss7_asp *asp, struct msgb *msg)
{
struct bsc_msc_data *msc;
struct gsm_subscriber_connection *conn;
char rcv_ep_local_name[1024];
struct osmo_sockaddr_str osa_str = {};
struct osmo_sockaddr osa = {};
socklen_t dest_len;
struct mgcp_client *mgcp_cli = NULL;
int rc;
LOGP(DMSC, LOGL_INFO, "%s: Received IPA-encapsulated MGCP: %s\n",
osmo_ss7_asp_get_name(asp), msg->l2h);
msc = msc_from_asp(asp);
if (!msc) {
rc = 0;
goto free_msg_ret;
}
rc = parse_local_endpoint_name(rcv_ep_local_name, sizeof(rcv_ep_local_name), (const char *)msg->l2h);
if (rc < 0) {
LOGP(DMSC, LOGL_ERROR, "(%s:) Received IPA-encapsulated MGCP: Failed to parse CIC\n",
osmo_ss7_asp_get_name(asp));
goto free_msg_ret;
}
/* Lookup which conn attached to the MSC holds an MGW endpoint with the
* name Endpoint Number as the one provided in the MGCP msg we received
* from MSC. Since CIC are unique per MSC, that's the same MGW in the
* pool where we have to forward the MGCP message. */
llist_for_each_entry(conn, &bsc_gsmnet->subscr_conns, entry) {
const char *ep_local_name;
if (conn->sccp.msc != msc)
continue; /* Only conns belonging to this MSC */
if (!conn->user_plane.mgw_endpoint)
continue;
ep_local_name = osmo_mgcpc_ep_local_name(conn->user_plane.mgw_endpoint);
LOGPFSMSL(conn->fi, DMSC, LOGL_DEBUG, "ep_local_name='%s' vs rcv_ep_local_name='%s'\n",
ep_local_name ? : "(null)", rcv_ep_local_name);
if (!ep_local_name)
continue;
if (strcmp(ep_local_name, rcv_ep_local_name) != 0)
continue;
mgcp_cli = osmo_mgcpc_ep_client(conn->user_plane.mgw_endpoint);
if (!mgcp_cli)
continue;
break;
}
if (!mgcp_cli) {
LOGP(DMSC, LOGL_ERROR, "(%s:) Received IPA-encapsulated MGCP: Failed to find associated MGW\n",
osmo_ss7_asp_get_name(asp));
rc = 0;
goto free_msg_ret;
}
rc = osmo_sockaddr_str_from_str(&osa_str, mgcp_client_remote_addr_str(mgcp_cli),
mgcp_client_remote_port(mgcp_cli));
if (rc < 0) {
LOGP(DMSC, LOGL_ERROR, "(%s:) Received IPA-encapsulated MGCP: Failed to parse MGCP address %s:%u\n",
osmo_ss7_asp_get_name(asp), mgcp_client_remote_addr_str(mgcp_cli), mgcp_client_remote_port(mgcp_cli));
goto free_msg_ret;
}
LOGP(DMSC, LOGL_NOTICE, "%s: Forwarding IPA-encapsulated MGCP to MGW at " OSMO_SOCKADDR_STR_FMT "\n",
osmo_ss7_asp_get_name(asp), OSMO_SOCKADDR_STR_FMT_ARGS_NOT_NULL(&osa_str));
rc = osmo_sockaddr_str_to_sockaddr(&osa_str, &osa.u.sas);
if (rc < 0) {
LOGP(DMSC, LOGL_ERROR, "(%s:) Received IPA-encapsulated MGCP: Failed to parse MGCP address " OSMO_SOCKADDR_STR_FMT "\n",
osmo_ss7_asp_get_name(asp), OSMO_SOCKADDR_STR_FMT_ARGS_NOT_NULL(&osa_str));
goto free_msg_ret;
}
dest_len = osmo_sockaddr_size(&osa);
/* we don't have a write queue here as we simply expect the socket buffers
* to be large enough to deal with whatever small/infrequent MGCP messages */
rc = sendto(msc->mgcp_ipa.ofd.fd, msgb_l2(msg), msgb_l2len(msg), 0, &osa.u.sa, dest_len);
free_msg_ret:
msgb_free(msg);
return rc;
}
/* we received some data on the UDP proxy socket from the MGW. Pass it to MSC via IPA */
int bsc_sccplite_mgcp_proxy_cb(struct osmo_fd *ofd, unsigned int what)
{
struct bsc_msc_data *msc = ofd->data;
struct msgb *msg;
int rc;
if (!(what & OSMO_FD_READ))
return 0;
msg = msgb_alloc_headroom(1024, 16, "MGCP->IPA");
OSMO_ASSERT(msg);
rc = recv(ofd->fd, msg->data, msgb_tailroom(msg), 0);
if (rc <= 0) {
LOGP(DMSC, LOGL_ERROR, "error receiving data from MGCP<->IPA proxy UDP socket: "
"%s\n", strerror(errno));
msgb_free(msg);
return rc;
}
msg->l2h = msgb_put(msg, rc);
msg->l2h[rc] = '\0';
LOGP(DMSC, LOGL_NOTICE, "Received MGCP on UDP proxy socket: %s\n", msg->l2h);
ipa_prepend_header(msg, IPAC_PROTO_MGCP_OLD);
return bsc_sccplite_msc_send(msc, msg);
}
|
