GPRS: Add script to track the N(U) on GPRS LLC messages..
tshark -q -X lua_script:gprs/gprs-verify-nu.lua -r trace.pcap
Output:
JUMP in N(U) on TLLI 3741437425 and SAPI: 9
last: 1 now: 3
JUMP in N(U) on TLLI 3741437425 and SAPI: 9
last: 10 now: 12
diff --git a/openbsc/contrib/gprs/gprs-verify-nu.lua b/openbsc/contrib/gprs/gprs-verify-nu.lua
new file mode 100644
index 0000000..63cc492
--- /dev/null
+++ b/openbsc/contrib/gprs/gprs-verify-nu.lua
@@ -0,0 +1,55 @@
+-- This script verifies that the N(U) is increasing...
+--
+do
+ local nu_state_src = {}
+
+ local function init_listener()
+ -- handle the port as NS over IP
+ local udp_port_table = DissectorTable.get("udp.port")
+ local gprs_ns_dis = Dissector.get("gprs_ns")
+ udp_port_table:add(23000,gprs_ns_dis)
+
+ -- we want to look here...
+ local llc_sapi_get = Field.new("llcgprs.sapib")
+ local llc_nu_get = Field.new("llcgprs.nu")
+ local bssgp_tlli_get = Field.new("bssgp.tlli")
+
+ local tap = Listener.new("ip", "udp.port == 23000")
+ function tap.packet(pinfo,tvb,ip)
+ local llc_sapi = llc_sapi_get()
+ local llc_nu = llc_nu_get()
+ local bssgp_tlli = bssgp_tlli_get()
+
+ if not llc_sapi or not llc_nu or not bssgp_tlli then
+ return
+ end
+
+ local ip_src = tostring(ip.ip_src)
+ local bssgp_ttli = tostring(bssgp_tlli)
+ local llc_nu = tostring(llc_nu)
+ local llc_sapi = tostring(llc_sapi)
+
+ local src_key = ip_src .. "-" .. bssgp_ttli .. "-" .. llc_sapi
+ local last_nu = nu_state_src[src_key]
+ if not last_nu then
+ -- print("Establishing mapping for " .. src_key)
+ nu_state_src[src_key] = llc_nu
+ return
+ end
+
+ nu_state_src[src_key] = llc_nu
+ if tonumber(last_nu) + 1 ~= tonumber(llc_nu) then
+ print("JUMP in N(U) on TLLI " .. bssgp_ttli .. " and SAPI: " .. llc_sapi)
+ print("\t last: " .. last_nu .. " now: " .. llc_nu)
+ end
+ end
+
+ function tap.draw()
+ end
+
+ function tap.reset()
+ end
+ end
+ init_listener()
+end
+