ms: Use the IMSI to retrieve the MS object

This commit extends get_ms() to really compare the IMSI if it has
been given. Matching by TLLI has a higher precedence than matching by
IMSI.

Ticket: #1674
Sponsored-by: On-Waves ehf
diff --git a/tests/ms/MsTest.cpp b/tests/ms/MsTest.cpp
index 75328f4..9c8ec2c 100644
--- a/tests/ms/MsTest.cpp
+++ b/tests/ms/MsTest.cpp
@@ -328,6 +328,9 @@
 static void test_ms_storage()
 {
 	uint32_t tlli = 0xffeeddbb;
+	const char *imsi1 = "001001987654321";
+	const char *imsi2 = "001001987654322";
+
 	gprs_rlcmac_ul_tbf *ul_tbf;
 	GprsMs *ms, *ms_tmp;
 	GprsMsStorage store;
@@ -343,19 +346,36 @@
 	ms = store.create_ms(tlli + 0, GPRS_RLCMAC_UL_TBF);
 	OSMO_ASSERT(ms != NULL);
 	OSMO_ASSERT(ms->tlli() == tlli + 0);
+	ms->set_imsi(imsi1);
+	OSMO_ASSERT(strcmp(ms->imsi(), imsi1) == 0);
 
 	ms_tmp = store.get_ms(tlli + 0);
 	OSMO_ASSERT(ms == ms_tmp);
 	OSMO_ASSERT(ms->tlli() == tlli + 0);
 
+	ms_tmp = store.get_ms(0, 0, imsi1);
+	OSMO_ASSERT(ms == ms_tmp);
+	OSMO_ASSERT(strcmp(ms->imsi(), imsi1) == 0);
+	ms_tmp = store.get_ms(0, 0, imsi2);
+	OSMO_ASSERT(ms_tmp == NULL);
+
 	ms = store.create_ms(tlli + 1, GPRS_RLCMAC_UL_TBF);
 	OSMO_ASSERT(ms != NULL);
 	OSMO_ASSERT(ms->tlli() == tlli + 1);
+	ms->set_imsi(imsi2);
+	OSMO_ASSERT(strcmp(ms->imsi(), imsi2) == 0);
 
 	ms_tmp = store.get_ms(tlli + 1);
 	OSMO_ASSERT(ms == ms_tmp);
 	OSMO_ASSERT(ms->tlli() == tlli + 1);
 
+	ms_tmp = store.get_ms(0, 0, imsi1);
+	OSMO_ASSERT(ms_tmp != NULL);
+	OSMO_ASSERT(ms_tmp != ms);
+	ms_tmp = store.get_ms(0, 0, imsi2);
+	OSMO_ASSERT(ms == ms_tmp);
+	OSMO_ASSERT(strcmp(ms->imsi(), imsi2) == 0);
+
 	/* delete ms */
 	ms = store.get_ms(tlli + 0);
 	OSMO_ASSERT(ms != NULL);
diff --git a/tests/ms/MsTest.err b/tests/ms/MsTest.err
index 4f704cb..86dbb5b 100644
--- a/tests/ms/MsTest.err
+++ b/tests/ms/MsTest.err
@@ -37,8 +37,10 @@
 Destroying MS object, TLLI = 0xff001111
 Creating MS object, TLLI = 0x00000000
 Modifying MS object, UL TLLI: 0x00000000 -> 0xffeeddbb, not yet confirmed
+Modifying MS object, TLLI = 0xffeeddbb, IMSI '' -> '001001987654321'
 Creating MS object, TLLI = 0x00000000
 Modifying MS object, UL TLLI: 0x00000000 -> 0xffeeddbc, not yet confirmed
+Modifying MS object, TLLI = 0xffeeddbc, IMSI '' -> '001001987654322'
 Attaching TBF to MS object, TLLI = 0xffeeddbb, TBF = TBF(TFI=0 TLLI=0x00000000 DIR=UL STATE=NULL)
 Detaching TBF from MS object, TLLI = 0xffeeddbb, TBF = TBF(TFI=0 TLLI=0x00000000 DIR=UL STATE=NULL)
 Destroying MS object, TLLI = 0xffeeddbb