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osmo-bsc-nat
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bsc_nat_fsm: initial msc <> bsc msg forwarding 

Add an initial implementation of sccp_sap_up, that assumes one BSC and
one MSC, and successfully forwards RESET and RESET ACK between both.

Related: SYS#5560
Depends: libosmo-sccp I0f38b0d038b0dd8cd355e7284e5b56d438811bd9
Change-Id: I4af398bb433341a98f818822e6c3af28b6d9dacd
This commit is contained in:
Oliver Smith 2022-01-19 10:51:27 +01:00
parent eefcdf8ed3
commit ba1f0d0691
2 changed files with 110 additions and 3 deletions
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8
doc/examples/osmo-bsc-nat/osmo-bsc-nat.cfg
View File

@ -3,12 +3,20 @@ cs7 instance 0
asp asp-clnt-OsmoBSCNAT-CN 2905 0 m3ua
remote-ip 127.0.0.1
local-ip 127.0.0.3
sccp-address msc
routing-indicator PC
point-code 0.23.1
subsystem-number 254
cs7 instance 1
point-code 0.23.1
asp asp-clnt-OsmoBSCNAT-RAN 2905 0 m3ua
remote-ip 127.0.0.2
local-ip 127.0.0.4
sccp-address bsc
routing-indicator PC
point-code 0.23.3
subsystem-number 254
bsc-nat
cs7-instance-cn 0

105
src/osmo-bsc-nat/bsc_nat_fsm.c
View File

@ -25,7 +25,10 @@
#include <osmocom/core/fsm.h>
#include <osmocom/core/select.h>
#include <osmocom/gsm/gsm0808.h>
#include <osmocom/sigtran/osmo_ss7.h>
#include <osmocom/sigtran/sccp_helpers.h>
#include <osmocom/bsc_nat/bsc_nat.h>
#include <osmocom/bsc_nat/bsc_nat_fsm.h>
@ -34,6 +37,18 @@
#define DEFAULT_PC_RAN "0.23.1" /* same as default for OsmoMSC */
#define DEFAULT_PC_CN "0.23.3" /* same as default for OsmoBSC */
static char log_buf[255];
#define LOG_SCCP(ss7_inst, peer_addr, level, fmt, args...) do { \
if (peer_addr) \
osmo_sccp_addr_to_str_buf(log_buf, sizeof(log_buf), NULL, peer_addr); \
LOGP(DMAIN, level, "(%s%s%s) " fmt, \
peer_addr ? log_buf : "", \
peer_addr ? " from " : "", \
ss7_inst == g_bsc_nat->ran ? "RAN" : "CN", \
## args); \
} while (0)
#define X(s) (1 << (s))
enum bsc_nat_fsm_states {
@ -47,11 +62,95 @@ enum bsc_nat_fsm_events {
BSC_NAT_FSM_EV_STOP,
};
static int sccp_sap_up(struct osmo_prim_hdr *oph, void *priv)
static struct bsc_nat_ss7_inst *ss7_inst_dest(struct bsc_nat_ss7_inst *src)
{
LOGP(DMAIN, LOGL_NOTICE, "STUB: sccp_sap_up() called\n");
if (src == g_bsc_nat->cn)
return g_bsc_nat->ran;
return g_bsc_nat->cn;
}
return 0;
static int sccp_sap_up(struct osmo_prim_hdr *oph, void *scu)
{
struct bsc_nat_ss7_inst *src = osmo_sccp_user_get_priv(scu);
struct bsc_nat_ss7_inst *dest = ss7_inst_dest(src);
struct osmo_scu_prim *prim = (struct osmo_scu_prim *) oph;
struct osmo_sccp_addr *my_addr;
struct osmo_sccp_addr *peer_addr;
char buf[255];
int rc = -1;
switch (OSMO_PRIM_HDR(oph)) {
case OSMO_PRIM(OSMO_SCU_PRIM_N_CONNECT, PRIM_OP_INDICATION):
/* indication of new inbound connection request */
peer_addr = &prim->u.connect.calling_addr;
LOG_SCCP(src, peer_addr, LOGL_DEBUG, "%s(%s)\n", __func__, osmo_scu_prim_name(oph));
break;
case OSMO_PRIM(OSMO_SCU_PRIM_N_DATA, PRIM_OP_INDICATION):
/* connection-oriented data received */
LOG_SCCP(src, NULL, LOGL_DEBUG, "%s(%s)\n", __func__, osmo_scu_prim_name(oph));
break;
case OSMO_PRIM(OSMO_SCU_PRIM_N_DISCONNECT, PRIM_OP_INDICATION):
/* indication of disconnect */
LOG_SCCP(src, NULL, LOGL_DEBUG, "%s(%s)\n", __func__, osmo_scu_prim_name(oph));
break;
case OSMO_PRIM(OSMO_SCU_PRIM_N_UNITDATA, PRIM_OP_INDICATION):
/* connection-less data received */
my_addr = &prim->u.unitdata.called_addr;
peer_addr = &prim->u.unitdata.calling_addr;
LOG_SCCP(src, peer_addr, LOGL_DEBUG, "%s(%s)\n", __func__, osmo_scu_prim_name(oph));
if (osmo_sccp_addr_ri_cmp(&src->local_sccp_addr, my_addr)) {
osmo_sccp_addr_to_str_buf(buf, sizeof(buf), NULL, my_addr);
LOG_SCCP(src, peer_addr, LOGL_ERROR, "Called address %s is not the locally configured"
" address %s\n", buf, osmo_sccp_inst_addr_name(NULL, &src->local_sccp_addr));
goto error;
}
/* Figure out called party in dest. TODO: build and use a
* mapping of peer_addr + conn_id <--> dest_ss7. For now, this
* is simplified by assuming there is only one MSC, one BSC. */
struct osmo_ss7_instance *dest_ss7;
struct osmo_sccp_addr dest_called;
dest_ss7 = osmo_ss7_instance_find(dest->ss7_id);
OSMO_ASSERT(dest_ss7);
if (src == g_bsc_nat->ran) {
if (osmo_sccp_addr_by_name_local(&dest_called, "msc", dest_ss7) < 0) {
LOG_SCCP(src, peer_addr, LOGL_ERROR, "Could not find MSC in address book\n");
goto error;
}
} else {
if (osmo_sccp_addr_by_name_local(&dest_called, "bsc", dest_ss7) < 0) {
LOG_SCCP(src, peer_addr, LOGL_ERROR, "Could not find BSC in address book\n");
goto error;
}
}
LOG_SCCP(src, peer_addr, LOGL_NOTICE, "Forwarding to %s in %s\n",
osmo_sccp_inst_addr_name(NULL, &dest_called),
dest == g_bsc_nat->ran ? "RAN" : "CN");
/* oph->msg stores oph and unitdata msg. Move oph->msg->data to
* unitdata msg and send it again. */
msgb_pull_to_l2(oph->msg);
osmo_sccp_tx_unitdata(dest->scu, &dest->local_sccp_addr, &dest_called, oph->msg->data,
msgb_length(oph->msg));
rc = 0;
break;
default:
LOG_SCCP(src, NULL, LOGL_DEBUG, "%s(%s)\n", __func__, osmo_scu_prim_name(oph));
break;
}
error:
msgb_free(oph->msg);
return rc;
}
static int ss7_inst_init(struct bsc_nat_ss7_inst *inst, const char *name, const char *default_pc_str,