gprs_ns2: inform the NS user (BSSGP) about the MTU of a NSE
The BSSGP layer needs to know the MTU of the NS UNIDATA payload.
The MTU can be 0 if the NSE doesn't contain any NSVC.
Every status indication will contain the mtu value.
The MTU in the status indication contains the maximum transfer
unit of a BSSGP message. From NS side the maximum SDU.
Related: OS#4889
Change-Id: I5016b295db6185ec131d83089cf6c806e34ef1b6
diff --git a/src/gb/gprs_ns2.c b/src/gb/gprs_ns2.c
index 99a7415..9302a16 100644
--- a/src/gb/gprs_ns2.c
+++ b/src/gb/gprs_ns2.c
@@ -217,6 +217,7 @@
{ GPRS_NS2_AFF_CAUSE_RECOVERY, "NSE recovery" },
{ GPRS_NS2_AFF_CAUSE_SNS_CONFIGURED, "NSE SNS configured" },
{ GPRS_NS2_AFF_CAUSE_SNS_FAILURE, "NSE SNS failure" },
+ { GPRS_NS2_AFF_CAUSE_MTU_CHANGE, "NSE MTU changed" },
{ 0, NULL }
};
@@ -496,15 +497,20 @@
nsp.u.status.transfer = ns2_count_transfer_cap(nse, bvci);
nsp.u.status.first = nse->first;
nsp.u.status.persistent = nse->persistent;
+ if (nse->mtu < 4)
+ nsp.u.status.mtu = 0;
+ else
+ nsp.u.status.mtu = nse->mtu - 4; /* 1 Byte NS PDU type, 1 Byte NS SDU control, 2 Byte BVCI */
+
if (nsvc) {
nsp.u.status.nsvc = gprs_ns2_ll_str_buf(nsvc_str, sizeof(nsvc_str), nsvc);
- LOGNSVC(nsvc, LOGL_NOTICE, "NS-STATUS.ind(bvci=%05u): cause=%s, transfer=%d, first=%d\n",
+ LOGNSVC(nsvc, LOGL_NOTICE, "NS-STATUS.ind(bvci=%05u): cause=%s, transfer=%d, first=%d, mtu=%d\n",
nsp.bvci, gprs_ns2_aff_cause_prim_str(nsp.u.status.cause),
- nsp.u.status.transfer, nsp.u.status.first);
+ nsp.u.status.transfer, nsp.u.status.first, nse->mtu);
} else {
- LOGNSE(nse, LOGL_NOTICE, "NS-STATUS.ind(bvci=%05u): cause=%s, transfer=%d, first=%d\n",
+ LOGNSE(nse, LOGL_NOTICE, "NS-STATUS.ind(bvci=%05u): cause=%s, transfer=%d, first=%d, mtu=%d\n",
nsp.bvci, gprs_ns2_aff_cause_prim_str(nsp.u.status.cause),
- nsp.u.status.transfer, nsp.u.status.first);
+ nsp.u.status.transfer, nsp.u.status.first, nse->mtu);
}
osmo_prim_init(&nsp.oph, SAP_NS, GPRS_NS2_PRIM_STATUS, PRIM_OP_INDICATION, NULL);
@@ -548,6 +554,7 @@
llist_add(&nsvc->list, &nse->nsvc);
llist_add(&nsvc->blist, &bind->nsvc);
+ ns2_nse_update_mtu(nse);
return nsvc;
@@ -746,6 +753,7 @@
nse->nsei = nsei;
nse->nsi = nsi;
nse->first = true;
+ nse->mtu = 0;
llist_add(&nse->list, &nsi->nse);
INIT_LLIST_HEAD(&nse->nsvc);
@@ -1334,6 +1342,31 @@
array[i] = bind;
}
+void ns2_nse_update_mtu(struct gprs_ns2_nse *nse)
+{
+ struct gprs_ns2_vc *nsvc;
+ int mtu = 0;
+
+ if (llist_empty(&nse->nsvc)) {
+ nse->mtu = 0;
+ return;
+ }
+
+ llist_for_each_entry(nsvc, &nse->nsvc, list) {
+ if (mtu == 0)
+ mtu = nsvc->bind->mtu;
+ else if (mtu > nsvc->bind->mtu)
+ mtu = nsvc->bind->mtu;
+ }
+
+ if (nse->mtu == mtu)
+ return;
+
+ nse->mtu = mtu;
+ if (nse->alive)
+ ns2_prim_status_ind(nsvc->nse, NULL, 0, GPRS_NS2_AFF_CAUSE_MTU_CHANGE);
+}
+
/*! calculate the transfer capabilities for a nse
* \param nse the nse to count the transfer capability
* \param bvci a bvci - unused
diff --git a/src/gb/gprs_ns2_fr.c b/src/gb/gprs_ns2_fr.c
index 7e6db2a..445f00a 100644
--- a/src/gb/gprs_ns2_fr.c
+++ b/src/gb/gprs_ns2_fr.c
@@ -801,6 +801,7 @@
bind->send_vc = fr_vc_sendmsg;
bind->free_vc = free_vc;
bind->dump_vty = dump_vty;
+ bind->mtu = FRAME_RELAY_SDU;
priv = bind->priv = talloc_zero(bind, struct priv_bind);
if (!priv) {
rc = -ENOMEM;
diff --git a/src/gb/gprs_ns2_frgre.c b/src/gb/gprs_ns2_frgre.c
index 177aeb2..62d87a4 100644
--- a/src/gb/gprs_ns2_frgre.c
+++ b/src/gb/gprs_ns2_frgre.c
@@ -572,6 +572,10 @@
bind->send_vc = frgre_vc_sendmsg;
bind->free_vc = free_vc;
bind->nsi = nsi;
+ /* TODO: allow to set the MTU via vty. It can not be automatic detected because it goes over an
+ * ethernet device and the MTU here must match the FR side of the FR-to-GRE gateway.
+ */
+ bind->mtu = FRAME_RELAY_SDU;
priv = bind->priv = talloc_zero(bind, struct priv_bind);
if (!priv) {
diff --git a/src/gb/gprs_ns2_internal.h b/src/gb/gprs_ns2_internal.h
index d4764f6..7e235be 100644
--- a/src/gb/gprs_ns2_internal.h
+++ b/src/gb/gprs_ns2_internal.h
@@ -179,6 +179,9 @@
/*! sum of all the signalling weight of _alive_ NS-VCs */
uint32_t sum_sig_weight;
+
+ /*! MTU of a NS PDU. This is the lowest MTU of all NSVCs */
+ uint16_t mtu;
};
/*! Structure representing a single NS-VC */
@@ -244,6 +247,9 @@
/*! transfer capability in mbit */
int transfer_capability;
+ /*! MTU of a NS PDU on this bind. */
+ uint16_t mtu;
+
/*! which link-layer are we based on? */
enum gprs_ns2_ll ll;
@@ -298,6 +304,7 @@
uint16_t bvci,
enum gprs_ns2_affecting_cause cause);
void ns2_nse_notify_alive(struct gprs_ns2_vc *nsvc, bool alive);
+void ns2_nse_update_mtu(struct gprs_ns2_nse *nse);
/* message */
int ns2_validate(struct gprs_ns2_vc *nsvc,
diff --git a/src/gb/gprs_ns2_udp.c b/src/gb/gprs_ns2_udp.c
index 0f22458..36f6a97 100644
--- a/src/gb/gprs_ns2_udp.c
+++ b/src/gb/gprs_ns2_udp.c
@@ -368,6 +368,10 @@
dscp, rc, errno);
}
+ /* IPv4: max fragmented payload can be (13 bit) * 8 byte => 65535.
+ * IPv6: max payload can be 65535 (RFC 2460).
+ * UDP header = 8 byte */
+ bind->mtu = 65535 - 8;
if (result)
*result = bind;