diff options
Diffstat (limited to 'openbsc/src/gprs/gb_proxy.c')
| -rw-r--r-- | openbsc/src/gprs/gb_proxy.c | 40 |
1 files changed, 35 insertions, 5 deletions
diff --git a/openbsc/src/gprs/gb_proxy.c b/openbsc/src/gprs/gb_proxy.c index 8b014eafc..fbac298e3 100644 --- a/openbsc/src/gprs/gb_proxy.c +++ b/openbsc/src/gprs/gb_proxy.c @@ -253,6 +253,22 @@ uint32_t gbproxy_make_sgsn_tlli(struct gbproxy_peer *peer, return sgsn_tlli; } +/* Returns != 0 iff IMSI acquisition was in progress */ +int gbproxy_reset_imsi_acquisition(struct gbproxy_tlli_info* tlli_info) +{ + int in_progress = 0; + if (!tlli_info) + return 0; + + if (tlli_info->imsi_acq_pending) + in_progress = 1; + + gbproxy_tlli_info_discard_messages(tlli_info); + tlli_info->imsi_acq_pending = 0; + + return in_progress; +} + /* patch BSSGP message */ static int gbprox_process_bssgp_ul(struct gbproxy_config *cfg, struct msgb *msg, @@ -315,10 +331,21 @@ static int gbprox_process_bssgp_ul(struct gbproxy_config *cfg, gbprox_update_current_raid(parse_ctx.bssgp_raid_enc, peer, parse_ctx.llc_msg_name); + gprs_gb_log_parse_context(&parse_ctx, "BSSGP"); + + tlli_info = gbproxy_update_tlli_state_ul(peer, now, &parse_ctx); + if (parse_ctx.g48_hdr) { switch (parse_ctx.g48_hdr->msg_type) { case GSM48_MT_GMM_ATTACH_REQ: rate_ctr_inc(&peer->ctrg->ctr[GBPROX_PEER_CTR_ATTACH_REQS]); + if (gbproxy_reset_imsi_acquisition(tlli_info)) { + LOGP(DLLC, LOGL_INFO, + "NSEI=%d(BSS) IMSI acquisition was in progress " + "when receiving an ATTACH_REQ.\n", + msgb_nsei(msg)); + tlli_info->imsi_acq_retries += 1; + } break; default: @@ -326,10 +353,6 @@ static int gbprox_process_bssgp_ul(struct gbproxy_config *cfg, } } - gprs_gb_log_parse_context(&parse_ctx, "BSSGP"); - - tlli_info = gbproxy_update_tlli_state_ul(peer, now, &parse_ctx); - if (tlli_info && cfg->route_to_sgsn2 && gbproxy_check_tlli(peer, tlli_info)) { sgsn_nsei = cfg->nsip_sgsn2_nsei; send_msg_directly = 1; @@ -415,8 +438,15 @@ static int gbprox_process_bssgp_ul(struct gbproxy_config *cfg, /* Send IDENT REQ */ idreq_msg = gsm48_msgb_alloc(); gprs_put_identity_req(idreq_msg, GSM_MI_TYPE_IMSI); + /* Workaround to avoid N(U) collisions and to enable a restart + * of the IMSI acquisition procedure. This will work unless the + * SGSN has an initial V(UT) within [256-32, 256+n_retries] + * (see GSM 04.64, 8.4.2). + * TODO: Check whether it is sensible to rely on this, it might + * be an issue when P-TMSI patching is _not_ enabled and the SGSN + * doesn't reset V(UT) after a detach. */ gprs_push_llc_ui(idreq_msg, 0, GPRS_SAPI_GMM, - /* TODO: use a real N(U) */0); + (tlli_info->imsi_acq_retries + 256) % 512); gprs_push_bssgp_dl_unitdata(idreq_msg, tlli_info->tlli.current); gbprox_relay2peer(idreq_msg, peer, msgb_bvci(msg)); msgb_free(idreq_msg); |