[PATCH] osmo-bts[master]: paging: Fix encoding of PAGING TYPE 3 Rest Octets

[Harald Welte]

Review at  https://gerrit.osmocom.org/6882

paging: Fix encoding of PAGING TYPE 3 Rest Octets

The RR PAGING TYPE 3 Rest Octets IE contains (among other things) the
channel type needed for Mobile Identity 3 + 4 in the paging message.

We did not only "forget" to encode those channel type needed field, but
we have a completely wrong definition of those rest octets in
libosmocore/include/gsm/protocol/gsm04_08.h "struct gsm48_paging3"

Change-Id: I3a0bca6707ce95b68459c89f5b2b07f1590a1ab3
Closes: OS#2994
---
M src/common/paging.c
1 file changed, 12 insertions(+), 8 deletions(-)


  git pull ssh://gerrit.osmocom.org:29418/osmo-bts refs/changes/82/6882/1

diff --git a/src/common/paging.c b/src/common/paging.c
index 4c4fd19..d2acd70 100644
--- a/src/common/paging.c
+++ b/src/common/paging.c
@@ -323,13 +323,12 @@
        return cur - out_buf;
 }
 
-static int fill_paging_type_3(uint8_t *out_buf, const uint8_t *tmsi1_lv,
-                               uint8_t cneed1, const uint8_t *tmsi2_lv,
-                               uint8_t cneed2, const uint8_t *tmsi3_lv,
-                               const uint8_t *tmsi4_lv)
+static int fill_paging_type_3(uint8_t *out_buf, const uint8_t *tmsi1_lv, 
uint8_t cneed1,
+                               const uint8_t *tmsi2_lv, uint8_t cneed2,
+                               const uint8_t *tmsi3_lv, uint8_t cneed3,
+                               const uint8_t *tmsi4_lv, uint8_t cneed4)
 {
        struct gsm48_paging3 *pt3 = (struct gsm48_paging3 *) out_buf;
-       uint8_t *cur;
 
        memset(out_buf, 0, sizeof(*pt3));
 
@@ -343,9 +342,12 @@
        tmsi_mi_to_uint(&pt3->tmsi3, tmsi3_lv);
        tmsi_mi_to_uint(&pt3->tmsi4, tmsi4_lv);
 
-       cur = out_buf + sizeof(*pt3);
+       /* The structure definition in libosmocore is wrong. It includes as last
+        * byte some invalid definition of chneed3/chneed4, so we must do this 
by hand
+        * here and cannot rely on sizeof(*pt3) */
+       out_buf[20] = (0x23 & ~0xf8) | 0x80 | (cneed3 & 3) << 5 | (cneed4 & 3) 
<< 3;
 
-       return cur - out_buf;
+       return 21;
 }
 
 static const uint8_t empty_id_lv[] = { 0x01, 0xF0 };
@@ -469,7 +471,9 @@
                                                 pr[1]->u.paging.identity_lv,
                                                 pr[1]->u.paging.chan_needed,
                                                 pr[2]->u.paging.identity_lv,
-                                                pr[3]->u.paging.identity_lv);
+                                                pr[2]->u.paging.chan_needed,
+                                                pr[3]->u.paging.identity_lv,
+                                                pr[3]->u.paging.chan_needed);
                } else if (num_pr >= 3 && num_imsi <= 1) {
                        /* 3 or 4, of which only up to 1 is IMSI */
                        DEBUGP(DPAG, "Tx PAGING TYPE 2 (2 TMSI,1 xMSI)\n");

-- 
To view, visit https://gerrit.osmocom.org/6882
To unsubscribe, visit https://gerrit.osmocom.org/settings

Gerrit-MessageType: newchange
Gerrit-Change-Id: I3a0bca6707ce95b68459c89f5b2b07f1590a1ab3
Gerrit-PatchSet: 1
Gerrit-Project: osmo-bts
Gerrit-Branch: master
Gerrit-Owner: Harald Welte <lafo...@gnumonks.org>