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Jacob Erlbeck jerlbeck at sysmocom.deUnder special circumstances (see below) receiving a NS-RESET leads to
duplicated NS-VC entries.
This patch changes gprs_ns_rx_reset() to check for this case and to
eventually delete the old entry. A new counter NS_CTR_REPLACED is
incremented each time when the NS-VC object is replaced. A new signal
S_NS_REPLACED is added which gets dispatched in this case, too.
This happens when the source port of a NS-VC changes to a new one
that has already been used by another NS-VC.
---
include/osmocom/gprs/gprs_ns.h | 3 ++
src/gb/gprs_ns.c | 83 ++++++++++++++++++++++++++++++++--------
tests/gb/gprs_ns_test.c | 9 +++++
tests/gb/gprs_ns_test.ok | 3 +-
4 files changed, 79 insertions(+), 19 deletions(-)
diff --git a/include/osmocom/gprs/gprs_ns.h b/include/osmocom/gprs/gprs_ns.h
index d16068b..cfcf8e2 100644
--- a/include/osmocom/gprs/gprs_ns.h
+++ b/include/osmocom/gprs/gprs_ns.h
@@ -119,6 +119,7 @@ struct gprs_nsvc {
unsigned int remote_end_is_sgsn:1;
unsigned int persistent:1;
+ unsigned int nsvci_is_valid:1;
struct rate_ctr_group *ctrg;
@@ -191,10 +192,12 @@ enum signal_ns {
S_NS_BLOCK,
S_NS_UNBLOCK,
S_NS_ALIVE_EXP, /* Tns-alive expired more than N times */
+ S_NS_REPLACED, /* nsvc object is replaced (sets old_nsvc) */
};
struct ns_signal_data {
struct gprs_nsvc *nsvc;
+ struct gprs_nsvc *old_nsvc;
uint8_t cause;
};
diff --git a/src/gb/gprs_ns.c b/src/gb/gprs_ns.c
index b5f91c4..03f39ef 100644
--- a/src/gb/gprs_ns.c
+++ b/src/gb/gprs_ns.c
@@ -100,15 +100,17 @@ enum ns_ctr {
NS_CTR_BYTES_OUT,
NS_CTR_BLOCKED,
NS_CTR_DEAD,
+ NS_CTR_REPLACED,
};
static const struct rate_ctr_desc nsvc_ctr_description[] = {
- { "packets.in", "Packets at NS Level ( In)" },
- { "packets.out","Packets at NS Level (Out)" },
- { "bytes.in", "Bytes at NS Level ( In)" },
- { "bytes.out", "Bytes at NS Level (Out)" },
- { "blocked", "NS-VC Block count " },
- { "dead", "NS-VC gone dead count " },
+ { "packets.in", "Packets at NS Level ( In)" },
+ { "packets.out","Packets at NS Level (Out)" },
+ { "bytes.in", "Bytes at NS Level ( In)" },
+ { "bytes.out", "Bytes at NS Level (Out)" },
+ { "blocked", "NS-VC Block count " },
+ { "dead", "NS-VC gone dead count " },
+ { "replaced", "NS-VC replaced other count" },
};
static const struct rate_ctr_group_desc nsvc_ctrg_desc = {
@@ -198,7 +200,7 @@ void gprs_nsvc_delete(struct gprs_nsvc *nsvc)
static void ns_osmo_signal_dispatch(struct gprs_nsvc *nsvc, unsigned int signal,
uint8_t cause)
{
- struct ns_signal_data nssd;
+ struct ns_signal_data nssd = {0};
nssd.nsvc = nsvc;
nssd.cause = cause;
@@ -206,6 +208,16 @@ static void ns_osmo_signal_dispatch(struct gprs_nsvc *nsvc, unsigned int signal,
osmo_signal_dispatch(SS_L_NS, signal, &nssd);
}
+static void ns_osmo_signal_dispatch_replaced(struct gprs_nsvc *nsvc, struct gprs_nsvc *old_nsvc)
+{
+ struct ns_signal_data nssd = {0};
+
+ nssd.nsvc = nsvc;
+ nssd.old_nsvc = old_nsvc;
+
+ osmo_signal_dispatch(SS_L_NS, S_NS_REPLACED, &nssd);
+}
+
/* Section 10.3.2, Table 13 */
static const struct value_string ns_cause_str[] = {
{ NS_CAUSE_TRANSIT_FAIL, "Transit network failure" },
@@ -651,8 +663,9 @@ static int gprs_ns_rx_reset(struct gprs_nsvc *nsvc, struct msgb *msg)
{
struct gprs_ns_hdr *nsh = (struct gprs_ns_hdr *) msg->l2h;
struct tlv_parsed tp;
- uint8_t *cause;
- uint16_t *nsvci, *nsei;
+ uint8_t cause;
+ uint16_t nsvci, nsei;
+ struct gprs_nsvc *other_nsvc = NULL;
int rc;
rc = tlv_parse(&tp, &ns_att_tlvdef, nsh->data,
@@ -671,22 +684,58 @@ static int gprs_ns_rx_reset(struct gprs_nsvc *nsvc, struct msgb *msg)
return -EINVAL;
}
- cause = (uint8_t *) TLVP_VAL(&tp, NS_IE_CAUSE);
- nsvci = (uint16_t *) TLVP_VAL(&tp, NS_IE_VCI);
- nsei = (uint16_t *) TLVP_VAL(&tp, NS_IE_NSEI);
+ cause = *(uint8_t *) TLVP_VAL(&tp, NS_IE_CAUSE);
+ nsvci = ntohs(*(uint16_t *) TLVP_VAL(&tp, NS_IE_VCI));
+ nsei = ntohs(*(uint16_t *) TLVP_VAL(&tp, NS_IE_NSEI));
+
+ LOGP(DNS, LOGL_INFO, "NSVCI=%u%s Rx NS RESET (NSEI=%u, NSVCI=%u, cause=%s)\n",
+ nsvc->nsvci, nsvc->nsvci_is_valid ? "" : "(invalid)",
+ nsei, nsvci, gprs_ns_cause_str(cause));
- LOGP(DNS, LOGL_INFO, "NSEI=%u Rx NS RESET (NSVCI=%u, cause=%s)\n",
- nsvc->nsvci, nsvc->nsei, gprs_ns_cause_str(*cause));
+ if (nsvc->nsvci_is_valid && nsvc->nsvci != nsvci) {
+ /* NS-VCI has changed */
+ other_nsvc = gprs_nsvc_by_nsvci(nsvc->nsi, nsvci);
+
+ if (other_nsvc) {
+ /* The NS-VCI is already used by this NS-VC */
+
+ struct rate_ctr_group *tmp_ctrg;
+ char *old_peer =
+ talloc_strdup(nsvc, gprs_ns_format_peer(other_nsvc));
+
+ LOGP(DNS, LOGL_INFO,
+ "NS-VC changed link (NSVCI=%u) from %s to %s\n",
+ nsvci, old_peer, gprs_ns_format_peer(nsvc));
+
+ talloc_free(old_peer);
+
+ /* Exchange the counters */
+ tmp_ctrg = nsvc->ctrg;
+ nsvc->ctrg = talloc_move(nsvc, &other_nsvc->ctrg);
+ other_nsvc->ctrg = talloc_move(other_nsvc, &tmp_ctrg);
+
+ rate_ctr_inc(&nsvc->ctrg->ctr[NS_CTR_REPLACED]);
+ }
+ }
/* Mark NS-VC as blocked and alive */
nsvc->state = NSE_S_BLOCKED | NSE_S_ALIVE;
- nsvc->nsei = ntohs(*nsei);
- nsvc->nsvci = ntohs(*nsvci);
+ nsvc->nsei = nsei;
+ nsvc->nsvci = nsvci;
+ nsvc->nsvci_is_valid = 1;
+
+ if (other_nsvc) {
+ ns_osmo_signal_dispatch_replaced(nsvc, other_nsvc);
+
+ /* Delete the 'old' object */
+ gprs_nsvc_delete(other_nsvc);
+ other_nsvc = NULL;
+ }
/* inform interested parties about the fact that this NSVC
* has received RESET */
- ns_osmo_signal_dispatch(nsvc, S_NS_RESET, *cause);
+ ns_osmo_signal_dispatch(nsvc, S_NS_RESET, cause);
rc = gprs_ns_tx_reset_ack(nsvc);
diff --git a/tests/gb/gprs_ns_test.c b/tests/gb/gprs_ns_test.c
index d41fccb..67e2eb9 100644
--- a/tests/gb/gprs_ns_test.c
+++ b/tests/gb/gprs_ns_test.c
@@ -155,6 +155,15 @@ static int test_signal(unsigned int subsys, unsigned int signal,
gprs_ns_format_peer(nssd->nsvc));
break;
+ case S_NS_REPLACED:
+ printf("==> got signal NS_REPLACED: 0x%04x/%s",
+ nssd->old_nsvc->nsvci,
+ gprs_ns_format_peer(nssd->old_nsvc));
+ printf(" -> 0x%04x/%s\n",
+ nssd->nsvc->nsvci,
+ gprs_ns_format_peer(nssd->nsvc));
+ break;
+
default:
printf("==> got signal %d, NS-VC 0x%04x/%s\n", signal,
nssd->nsvc->nsvci,
diff --git a/tests/gb/gprs_ns_test.ok b/tests/gb/gprs_ns_test.ok
index 01b1bc9..cc9e76c 100644
--- a/tests/gb/gprs_ns_test.ok
+++ b/tests/gb/gprs_ns_test.ok
@@ -97,6 +97,7 @@ Current NS-VCIs:
PROCESSING RESET from 0x01020304:3333
02 00 81 01 01 82 11 22 04 82 11 22
+==> got signal NS_REPLACED: 0x1122/1.2.3.4:4444 -> 0x1122/1.2.3.4:3333
==> got signal NS_RESET, NS-VC 0x1122/1.2.3.4:3333
RESPONSE, msg length 9
03 01 82 11 22 04 82 11 22
@@ -108,7 +109,6 @@ result (RESET) = 9
Current NS-VCIs:
VCI 0x1122, NSEI 0x1122, peer 0x01020304:3333
- VCI 0x1122, NSEI 0x3344, peer 0x01020304:4444
--- Peer port 4444, RESET, NSEI is changed back ---
@@ -125,7 +125,6 @@ RESPONSE, msg length 1
result (RESET) = 9
Current NS-VCIs:
- VCI 0x1122, NSEI 0x1122, peer 0x01020304:3333
VCI 0x1122, NSEI 0x1122, peer 0x01020304:4444
===== NS protocol test END
--
1.7.9.5