221 lines
6.3 KiB
C
221 lines
6.3 KiB
C
/* GPRS LLC protocol primitive implementation as per 3GPP TS 44.064 */
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/*
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* (C) 2022 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
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*
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* All Rights Reserved
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include <stdint.h>
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#include <errno.h>
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#include <osmocom/core/msgb.h>
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#include <osmocom/core/utils.h>
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#include <osmocom/core/logging.h>
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#include <osmocom/gprs/llc/llc.h>
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#include <osmocom/gprs/llc/llc_prim.h>
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#include <osmocom/gprs/llc/llc_private.h>
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#define LLC_MSGB_HEADROOM 0
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const struct value_string osmo_gprs_llc_prim_sap_names[] = {
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{ OSMO_GPRS_LLC_SAP_LLGM, "LLGM" },
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{ OSMO_GPRS_LLC_SAP_LL, "LL" },
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{ OSMO_GPRS_LLC_SAP_GRR, "GRR" },
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{ OSMO_GPRS_LLC_SAP_BSSGP, "BSSGP" },
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{ 0, NULL }
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};
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const char *osmo_gprs_llc_prim_name(const struct osmo_gprs_llc_prim *llc_prim)
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{
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static char name_buf[256];
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const char *sap = osmo_gprs_llc_prim_sap_name(llc_prim->oph.sap);
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const char *op = get_value_string(osmo_prim_op_names, llc_prim->oph.operation);
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const char *type;
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switch (llc_prim->oph.sap) {
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case OSMO_GPRS_LLC_SAP_LLGM:
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type = osmo_gprs_llc_llgmm_prim_type_name(llc_prim->oph.primitive);
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break;
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case OSMO_GPRS_LLC_SAP_LL:
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type = osmo_gprs_llc_ll_prim_type_name(llc_prim->oph.primitive);
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break;
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case OSMO_GPRS_LLC_SAP_GRR:
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type = osmo_gprs_llc_grr_prim_type_name(llc_prim->oph.primitive);
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break;
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case OSMO_GPRS_LLC_SAP_BSSGP:
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type = osmo_gprs_llc_bssgp_prim_type_name(llc_prim->oph.primitive);
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break;
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default:
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type = "unsupported-llc-sap";
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}
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snprintf(name_buf, sizeof(name_buf), "%s-%s.%s", sap, type, op);
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return name_buf;
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}
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static int llc_up_cb_dummy(struct osmo_gprs_llc_prim *llc_prim, void *user_data)
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{
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LOGLLC(LOGL_INFO, "llc_up_cb_dummy(%s)\n", osmo_gprs_llc_prim_name(llc_prim));
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return 0;
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}
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static int llc_down_cb_dummy(struct osmo_gprs_llc_prim *llc_prim, void *user_data)
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{
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LOGLLC(LOGL_INFO, "llc_down_cb_dummy(%s)\n", osmo_gprs_llc_prim_name(llc_prim));
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return 0;
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}
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/* Set callback used by LLC layer to push primitives to higher layers in protocol stack */
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void osmo_gprs_llc_prim_set_up_cb(osmo_gprs_llc_prim_up_cb up_cb, void *up_user_data)
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{
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g_ctx->llc_up_cb = up_cb;
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g_ctx->llc_up_cb_user_data = up_user_data;
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}
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/* Set callback used by LLC layer to push primitives to lower layers in protocol stack */
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void osmo_gprs_llc_prim_set_down_cb(osmo_gprs_llc_prim_down_cb down_cb, void *down_user_data)
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{
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g_ctx->llc_down_cb = down_cb;
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g_ctx->llc_down_cb_user_data = down_user_data;
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}
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/********************************
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* Primitive allocation:
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********************************/
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/* allocate a msgb containing a struct osmo_gprs_llc_prim + optional l3 data */
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static struct msgb *gprs_llc_prim_msgb_alloc(unsigned int l3_len)
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{
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const int headroom = LLC_MSGB_HEADROOM;
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const int size = headroom + sizeof(struct osmo_gprs_llc_prim) + l3_len;
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struct msgb *msg = msgb_alloc_headroom(size, headroom, "llc_prim");
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if (!msg)
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return NULL;
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msg->l1h = msgb_put(msg, sizeof(struct osmo_gprs_llc_prim));
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return msg;
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}
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struct osmo_gprs_llc_prim *gprs_llc_prim_alloc(enum osmo_gprs_llc_prim_sap sap, unsigned int type,
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enum osmo_prim_operation operation,
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unsigned int l3_len)
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{
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struct msgb *msg = gprs_llc_prim_msgb_alloc(l3_len);
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struct osmo_gprs_llc_prim *llc_prim = msgb_llc_prim(msg);
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osmo_prim_init(&llc_prim->oph, sap, type, operation, msg);
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return llc_prim;
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}
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int gprs_llc_prim_handle_unsupported(struct osmo_gprs_llc_prim *llc_prim)
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{
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LOGLLC(LOGL_ERROR, "Unsupported llc_prim! %s\n", osmo_gprs_llc_prim_name(llc_prim));
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msgb_free(llc_prim->oph.msg);
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return -ENOTSUP;
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}
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/********************************
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* Handling from/to upper layers:
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********************************/
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int gprs_llc_prim_call_up_cb(struct osmo_gprs_llc_prim *llc_prim)
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{
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int rc;
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if (g_ctx->llc_up_cb)
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rc = g_ctx->llc_up_cb(llc_prim, g_ctx->llc_up_cb_user_data);
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else
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rc = llc_up_cb_dummy(llc_prim, g_ctx->llc_up_cb_user_data);
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/* Special return value '1' means: do not free */
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if (rc != 1)
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msgb_free(llc_prim->oph.msg);
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return rc;
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}
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/* LLC higher layers push LLC primitive down to LLC layer: */
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int osmo_gprs_llc_prim_upper_down(struct osmo_gprs_llc_prim *llc_prim)
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{
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int rc;
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OSMO_ASSERT(g_ctx);
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LOGLLC(LOGL_INFO, "Rx from upper layers: %s\n", osmo_gprs_llc_prim_name(llc_prim));
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switch (llc_prim->oph.sap) {
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case OSMO_GPRS_LLC_SAP_LLGM:
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rc = gprs_llc_prim_llgmm_upper_down(llc_prim);
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break;
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case OSMO_GPRS_LLC_SAP_LL:
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rc = gprs_llc_prim_ll_upper_down(llc_prim);
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break;
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default:
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rc = gprs_llc_prim_handle_unsupported(llc_prim);
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}
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return rc;
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}
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/********************************
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* Handling from/to lower layers:
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********************************/
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int gprs_llc_prim_call_down_cb(struct osmo_gprs_llc_prim *llc_prim)
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{
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int rc;
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if (g_ctx->llc_down_cb)
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rc = g_ctx->llc_down_cb(llc_prim, g_ctx->llc_down_cb_user_data);
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else
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rc = llc_down_cb_dummy(llc_prim, g_ctx->llc_down_cb_user_data);
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/* Special return value '1' means: do not free */
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if (rc != 1)
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msgb_free(llc_prim->oph.msg);
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else
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rc = 0;
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return rc;
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}
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/* LLC lower layers push LLC primitive up to LLC layer: */
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int osmo_gprs_llc_prim_lower_up(struct osmo_gprs_llc_prim *llc_prim)
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{
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OSMO_ASSERT(g_ctx);
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OSMO_ASSERT(llc_prim);
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struct msgb *msg = llc_prim->oph.msg;
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int rc;
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LOGLLC(LOGL_INFO, "Rx from lower layers: %s\n", osmo_gprs_llc_prim_name(llc_prim));
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switch (llc_prim->oph.sap) {
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case OSMO_GPRS_LLC_SAP_GRR:
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OSMO_ASSERT(g_ctx->location == OSMO_GPRS_LLC_LOCATION_MS);
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rc = gprs_llc_prim_lower_up_grr(llc_prim);
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break;
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case OSMO_GPRS_LLC_SAP_BSSGP:
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OSMO_ASSERT(g_ctx->location == OSMO_GPRS_LLC_LOCATION_SGSN);
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rc = gprs_llc_prim_lower_up_bssgp(llc_prim);
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break;
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default:
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rc = -EINVAL;
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}
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/* Special return value '1' means: do not free */
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if (rc != 1)
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msgb_free(msg);
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else
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rc = 0;
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return rc;
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}
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