If a Create Bearer Response occurs after a Delete Bearer Response,
SGW-C crashes.
The execution is stopped by the following ASSERT
because it tries to access the UL Tunnel
deleted by the Delete Bearer Response.
```
03/28 17:28:41.229: [gtp] DEBUG: [7] LOCAL Find GTPv2 peer [172.22.0.9]:2123 (../lib/gtp/xact.c:949)
03/28 17:28:41.229: [gtp] DEBUG: [7] LOCAL Receive peer [172.22.0.9]:2123 (../lib/gtp/xact.c:966)
03/28 17:28:41.229: [gtp] DEBUG: [7] LOCAL UPD RX-96 peer [172.22.0.9]:2123 (../lib/gtp/xact.c:448)
03/28 17:28:41.229: [sgwc] DEBUG: Create Bearer Response (../src/sgwc/s11-handler.c:707)
03/28 17:28:41.229: [gtp] DEBUG: [7] LOCAL Commit peer [172.22.0.9]:2123 (../lib/gtp/xact.c:629)
03/28 17:28:41.230: [gtp] DEBUG: [7] LOCAL Delete peer [172.22.0.9]:2123 (../lib/gtp/xact.c:1149)
03/28 17:28:41.230: [sgwc] FATAL: sgwc_s11_handle_create_bearer_response: Assertion `ul_tunnel' failed. (../src/sgwc/s11-handler.c:802)
03/28 17:28:41.231: [core] FATAL: backtrace() returned 8 addresses (../lib/core/ogs-abort.c:37)
./open5gs-sgwcd(+0x189b7) [0x5b3c92cf09b7]
./open5gs-sgwcd(+0x13c6d) [0x5b3c92cebc6d]
/open5gs/install/lib/x86_64-linux-gnu/libogscore.so.2(ogs_fsm_dispatch+0x113) [0x70600ed63402]
./open5gs-sgwcd(+0x629d) [0x5b3c92cde29d]
/open5gs/install/lib/x86_64-linux-gnu/libogscore.so.2(+0x11754) [0x70600ed54754]
/lib/x86_64-linux-gnu/libpthread.so.0(+0x8609) [0x70600ecfc609]
/lib/x86_64-linux-gnu/libc.so.6(clone+0x43) [0x70600ec21353]
```
To solve this problem, I have modified to handle the exception appropriately,
display the error situation in the Cause of the Create Bearer Response,
and proceed with the execution.
If eg. PCRF or AAA diameter link is not yet ready (eg. PCRF crashed), and
a client sends a CreateSessionRequest announcing its ow F-TEID,
then open5gs-smfd answers with Create Session Response Cause=
"Remote peer not responding", but it is not setting the received F-TEID
in the header of the response, instead it sends with TEI=0.
As a result, the peer cannot match the CreateSessionResponse, and needs
to rely on its own timeout timer to figure out that specific request failed.
This also happens in PFCP, so to solve this problem, I added teid/seid_presence
to the interface that sends the error message as shown below.
void ogs_gtp2_send_error_message(ogs_gtp_xact_t *xact,
int teid_presence, uint32_t teid, uint8_t type, uint8_t cause_value);
void ogs_pfcp_send_error_message(
ogs_pfcp_xact_t *xact, int seid_presence, uint64_t seid, uint8_t type,
uint8_t cause_value, uint16_t offending_ie_value);
All process will be forcely exited if it failed to encode the S1AP/NGAP/GTP/PFCP message. It is to make sure there was no problem with the encoding of open5gs.
* Flow-Description use 'to assigned' in Gx Interface
* Support SDF Filter ID
* Support F-TEID's Choose
* BAR(Buffering) is added in PFCP session
* Default Apply Action uses NOCP|BUFF
So far, no operation was performed when Error Indication was received
from eNodeB. For that reason, I solved #568 issues by controlling
the MME to prevent this from happening.
Now, when GTP-U Error Indication is received, MME and SGW are implemented
to do what they have to do. I hope that the network can be restored
by responding appropriately even if Error Indication occurs.
- Set the number of UEs in units of AMF/MME instead of gNB/eNB.
- See default value as shown below
Number of UEs per AMF/MME : 4,096
Number of gNB/eNB per AMF/MME : 32
Sukchan Lee