[GPRS] Initial untested support for libgtp
libgtp of the OpenGGSN project will allow us to speak the GTPv0/v1
protocol of the interface between SGSN and GGSN.
This commit includes code for the main libgtp integration (file
descriptor, select loop, timer) as well as code to encode/send
a CREATE PDP CONTEXT request.
diff --git a/openbsc/src/gprs/sgsn_libgtp.c b/openbsc/src/gprs/sgsn_libgtp.c
new file mode 100644
index 0000000..fcaee8b
--- /dev/null
+++ b/openbsc/src/gprs/sgsn_libgtp.c
@@ -0,0 +1,421 @@
+/* GPRS SGSN integration with libgtp of OpenGGSN */
+
+/* (C) 2010 by Harald Welte <laforge@gnumonks.org>
+ * (C) 2010 by On Waves
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <getopt.h>
+#include <errno.h>
+#include <signal.h>
+#include <sys/fcntl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#include <osmocore/talloc.h>
+#include <osmocore/select.h>
+#include <osmocore/rate_ctr.h>
+
+#include <openbsc/signal.h>
+#include <openbsc/debug.h>
+#include <openbsc/sgsn.h>
+//#include <openbsc/gprs_ns.h>
+//#include <openbsc/gprs_bssgp.h>
+#include <openbsc/gprs_sgsn.h>
+#include <openbsc/gsm_04_08_gprs.h>
+
+#include <gtp.h>
+#include <pdp.h>
+
+struct ggsn_ctx {
+ unsigned int gtp_version;
+ struct in_addr remote_addr;
+ struct gsn_t *gsn;
+};
+
+const struct value_string gtp_cause_strs[] = {
+ { GTPCAUSE_REQ_IMSI, "Request IMSI" },
+ { GTPCAUSE_REQ_IMEI, "Request IMEI" },
+ { GTPCAUSE_REQ_IMSI_IMEI, "Request IMSI and IMEI" },
+ { GTPCAUSE_NO_ID_NEEDED, "No identity needed" },
+ { GTPCAUSE_MS_REFUSES_X, "MS refuses" },
+ { GTPCAUSE_MS_NOT_RESP_X, "MS is not GPRS responding" },
+ { GTPCAUSE_ACC_REQ, "Request accepted" },
+ { GTPCAUSE_NON_EXIST, "Non-existent" },
+ { GTPCAUSE_INVALID_MESSAGE, "Invalid message format" },
+ { GTPCAUSE_IMSI_NOT_KNOWN, "IMSI not known" },
+ { GTPCAUSE_MS_DETACHED, "MS is GPRS detached" },
+ { GTPCAUSE_MS_NOT_RESP, "MS is not GPRS responding" },
+ { GTPCAUSE_MS_REFUSES, "MS refuses" },
+ { GTPCAUSE_NO_RESOURCES, "No resources available" },
+ { GTPCAUSE_NOT_SUPPORTED, "Service not supported" },
+ { GTPCAUSE_MAN_IE_INCORRECT, "Mandatory IE incorrect" },
+ { GTPCAUSE_MAN_IE_MISSING, "Mandatory IE missing" },
+ { GTPCAUSE_OPT_IE_INCORRECT, "Optional IE incorrect" },
+ { GTPCAUSE_SYS_FAIL, "System failure" },
+ { GTPCAUSE_ROAMING_REST, "Roaming restrictions" },
+ { GTPCAUSE_PTIMSI_MISMATCH, "P-TMSI Signature mismatch" },
+ { GTPCAUSE_CONN_SUSP, "GPRS connection suspended" },
+ { GTPCAUSE_AUTH_FAIL, "Authentication failure" },
+ { GTPCAUSE_USER_AUTH_FAIL, "User authentication failed" },
+ { GTPCAUSE_CONTEXT_NOT_FOUND, "Context not found" },
+ { GTPCAUSE_ADDR_OCCUPIED, "All dynamic PDP addresses occupied" },
+ { GTPCAUSE_NO_MEMORY, "No memory is available" },
+ { GTPCAUSE_RELOC_FAIL, "Relocation failure" },
+ { GTPCAUSE_UNKNOWN_MAN_EXTHEADER, "Unknown mandatory ext. header" },
+ { GTPCAUSE_SEM_ERR_TFT, "Semantic error in TFT operation" },
+ { GTPCAUSE_SYN_ERR_TFT, "Syntactic error in TFT operation" },
+ { GTPCAUSE_SEM_ERR_FILTER, "Semantic errors in packet filter" },
+ { GTPCAUSE_SYN_ERR_FILTER, "Syntactic errors in packet filter" },
+ { GTPCAUSE_MISSING_APN, "Missing or unknown APN" },
+ { GTPCAUSE_UNKNOWN_PDP, "Unknown PDP address or PDP type" },
+ { 0, NULL }
+};
+
+/* generate a PDP context based on the IE's from the 04.08 message,
+ * and send the GTP create pdp context request to the GGSN */
+int sgsn_create_pdp_ctx(struct ggsn_ctx *ggsn, struct sgsn_mm_ctx *mmctx,
+ uint16_t nsapi, struct tlv_parsed *tp)
+{
+ struct sgsn_instance *sgsn = mmctx->sgsn;
+ struct pdp_t *pdp;
+ uint64_t imsi_ui64;
+ int rc;
+
+ rc = pdp_newpdp(&pdp, imsi_ui64, nsapi, NULL);
+ if (rc) {
+ LOGP(DGPRS, LOGL_ERROR, "Out of PDP Contexts\n");
+ return -ENOMEM;
+ }
+ //pdp->peer = /* sockaddr_in of GGSN (receive) */
+ //pdp->ipif = /* not used by library */
+ pdp->version = ggsn->gtp_version;
+ pdp->hisaddr0 = ggsn->remote_addr;
+ pdp->hisaddr1 = ggsn->remote_addr;
+ //pdp->cch_pdp = 512; /* Charging Flat Rate */
+
+ /* MS provided APN, subscription not verified */
+ pdp->selmode = 0x01;
+
+ /* IMSI, TEID/TEIC, FLLU/FLLC, TID, NSAPI set in pdp_newpdp */
+
+ /* FIXME: MSISDN in BCD format from mmctx */
+ //pdp->msisdn.l/.v
+
+ /* End User Address from GMM requested PDP address */
+ pdp->eua.l = TLVP_LEN(tp, OSMO_IE_GSM_REQ_PDP_ADDR);
+ if (pdp->eua.l > sizeof(pdp->eua.v))
+ pdp->eua.l = sizeof(pdp->eua.v);
+ memcpy(pdp->eua.v, TLVP_VAL(tp, OSMO_IE_GSM_REQ_PDP_ADDR),
+ pdp->eua.l);
+ /* Highest 4 bits of first byte need to be set to 1, otherwise
+ * the IE is identical with the 04.08 PDP Address IE */
+ pdp->eua.v[0] |= 0xf0;
+
+ /* APN name from GMM */
+ pdp->apn_use.l = TLVP_LEN(tp, GSM48_IE_GSM_APN);
+ if (pdp->apn_use.l > sizeof(pdp->apn_use.v))
+ pdp->apn_use.l = sizeof(pdp->apn_use.v);
+ memcpy(pdp->apn_use.v, TLVP_VAL(tp, GSM48_IE_GSM_APN),
+ pdp->apn_use.l);
+
+ /* Protocol Configuration Options from GMM */
+ pdp->pco_req.l = TLVP_LEN(tp, GSM48_IE_GSM_PROTO_CONF_OPT);
+ if (pdp->pco_req.l > sizeof(pdp->pco_req.v))
+ pdp->pco_req.l = sizeof(pdp->pco_req.v);
+ memcpy(pdp->pco_req.v, TLVP_VAL(tp, GSM48_IE_GSM_PROTO_CONF_OPT),
+ pdp->pco_req.l);
+
+ /* QoS options from GMM */
+ pdp->qos_req.l = TLVP_LEN(tp, OSMO_IE_GSM_REQ_QOS);
+ if (pdp->qos_req.l > sizeof(pdp->qos_req.v))
+ pdp->qos_req.l = sizeof(pdp->qos_req.v);
+ memcpy(pdp->qos_req.v, TLVP_VAL(tp, OSMO_IE_GSM_REQ_QOS),
+ pdp->qos_req.l);
+
+ /* SGSN address for control plane */
+ pdp->gsnlc.l = sizeof(sgsn->cfg.gtp_listenaddr);
+ memcpy(pdp->gsnlc.v, &sgsn->cfg.gtp_listenaddr,
+ sizeof(sgsn->cfg.gtp_listenaddr));
+
+ /* SGSN address for user plane */
+ pdp->gsnlu.l = sizeof(sgsn->cfg.gtp_listenaddr);
+ memcpy(pdp->gsnlu.v, &sgsn->cfg.gtp_listenaddr,
+ sizeof(sgsn->cfg.gtp_listenaddr));
+
+ /* FIXME: change pdp state to 'requested' */
+
+ /* FIXME: pass along a pointer to the MM CTX */
+ return gtp_create_context_req(ggsn->gsn, pdp, mmctx);
+}
+
+/* The GGSN has confirmed the creation of a PDP Context */
+static int create_pdp_conf(struct pdp_t *pdp, void *cbp, int cause)
+{
+ struct sgsn_mm_ctx *mmctx = cbp;
+
+ DEBUGP(DGPRS, "Received CREATE PDP CTX CONF, cause=%d(%s)\n",
+ cause, get_value_string(gtp_cause_strs, cause));
+
+ /* Check for cause value if it was really successful */
+ if (cause < 0) {
+ LOGP(DGPRS, LOGL_NOTICE, "Create PDP ctx req timed out\n");
+ if (pdp->version == 1) {
+ pdp->version = 0;
+ gtp_create_context_req(mmctx->sgsn->gsn, pdp, cbp);
+ return 0;
+ } else {
+ pdp_freepdp(pdp);
+ return EOF;
+ }
+ }
+
+ /* Check for cause value if it was really successful */
+ if (cause != GTPCAUSE_ACC_REQ) {
+ pdp_freepdp(pdp);
+ return EOF;
+ }
+
+ /* FIXME: Determine MM ctx for the PDP ctx */
+ /* FIXME: Send PDP CTX ACT ACK/REJ to MS */
+ return 0;
+}
+
+/* If we receive a 04.08 DEACT PDP CTX REQ or GPRS DETACH, we need to
+ * look-up the PDP context and request its deletion from the SGSN */
+int sgsn_delete_pdp_ctx(struct ggsn_ctx *ggsn, struct sgsn_mm_ctx *mmctx,
+ struct tlv_parsed *tp)
+{
+ //return gtp_delete_context_req(gsn, pdp, cbp, teardown);
+}
+
+/* Confirmation of a PDP Context Delete */
+static int delete_pdp_conf(struct pdp_t *pdp, int cause)
+{
+ DEBUGP(DGPRS, "Received DELETE PDP CTX CONF, cause=%d(%s)\n",
+ cause, get_value_string(gtp_cause_strs, cause));
+ return 0;
+}
+
+/* Confirmation of an GTP ECHO request */
+static int echo_conf(int recovery)
+{
+ if (recovery < 0) {
+ DEBUGP(DGPRS, "GTP Echo Request timed out\n");
+ /* FIXME: if version == 1, retry with version 0 */
+ } else {
+ DEBUGP(DGPRS, "GTP Rx Echo Response\n");
+ }
+ return 0;
+}
+
+/* libgtp callback for confirmations */
+static int cb_conf(int type, int cause, struct pdp_t *pdp, void *cbp)
+{
+ DEBUGP(DGPRS, "libgtp cb_conf(type=%d, cause=%d, pdp=%p, cbp=%p)\n",
+ type, cause, pdp, cbp);
+
+ if (cause == EOF)
+ LOGP(DGPRS, LOGL_ERROR, "libgtp EOF (type=%u, pdp=%p, cbp=%p)\n",
+ type, pdp, cbp);
+
+ switch (type) {
+ case GTP_ECHO_REQ:
+ return echo_conf(cause);
+ case GTP_CREATE_PDP_REQ:
+ return create_pdp_conf(pdp, cbp, cause);
+ case GTP_DELETE_PDP_REQ:
+ return delete_pdp_conf(pdp, cause);
+ default:
+ break;
+ }
+ return 0;
+}
+
+/* Called whenever a PDP context is deleted for any reason */
+static int cb_delete_context(struct pdp_t *pdp)
+{
+ LOGP(DGPRS, LOGL_INFO, "PDP Context was deleted\n");
+ return 0;
+}
+
+/* Called when we receive a Version Not Supported message */
+static int cb_unsup_ind(struct sockaddr_in *peer)
+{
+ LOGP(DGPRS, LOGL_INFO, "GTP Version not supported Indication "
+ "from %s:%u\n", inet_ntoa(peer->sin_addr),
+ ntohs(peer->sin_port));
+ return 0;
+}
+
+/* Called when we receive a Supported Ext Headers Notification */
+static int cb_extheader_ind(struct sockaddr_in *peer)
+{
+ LOGP(DGPRS, LOGL_INFO, "GTP Supported Ext Headers Noficiation "
+ "from %s:%u\n", inet_ntoa(peer->sin_addr),
+ ntohs(peer->sin_port));
+ return 0;
+}
+
+/* Called whenever we recive a DATA packet */
+static int cb_data_ind(struct pdp_t *pdp, void *packet, unsigned int len)
+{
+ DEBUGP(DGPRS, "GTP DATA IND from GGSN, length=%u\n", len);
+
+ return 0;
+}
+
+/* libgtp select loop integration */
+static int sgsn_gtp_fd_cb(struct bsc_fd *fd, unsigned int what)
+{
+ struct sgsn_instance *sgi = fd->data;
+ int rc;
+
+ if (!(what & BSC_FD_READ))
+ return 0;
+
+ switch (fd->priv_nr) {
+ case 0:
+ rc = gtp_decaps0(sgi->gsn);
+ break;
+ case 1:
+ rc = gtp_decaps1c(sgi->gsn);
+ break;
+ case 2:
+ rc = gtp_decaps1u(sgi->gsn);
+ break;
+ }
+ return rc;
+}
+
+static void timeval_normalize(struct timeval *tv)
+{
+ unsigned int sec = tv->tv_usec / 1000000;
+ tv->tv_sec += sec;
+ tv->tv_usec -= sec * 1000000;
+}
+
+/* diff = a - b */
+static int timeval_diff(struct timeval *diff,
+ struct timeval *a,
+ struct timeval *b)
+{
+ /* Step 1: normalize input values */
+ timeval_normalize(a);
+ timeval_normalize(b);
+
+ if (b->tv_sec > a->tv_sec ||
+ b->tv_sec == a->tv_sec && b->tv_usec > a->tv_usec) {
+ b->tv_sec = b->tv_usec = 0;
+ return -ERANGE;
+ }
+
+ if (b->tv_usec > a->tv_usec) {
+ a->tv_sec -= 1;
+ a->tv_usec += 1000000;
+ }
+
+ diff->tv_usec = a->tv_usec - b->tv_usec;
+ diff->tv_sec = a->tv_sec - b->tv_sec;
+
+ return 0;
+}
+
+static void sgsn_gtp_tmr_start(struct sgsn_instance *sgi)
+{
+ struct timeval now, next, diff;
+
+ /* Retrieve next retransmission as struct timeval */
+ gtp_retranstimeout(sgi->gsn, &next);
+
+ /* Calculate the difference to now */
+ gettimeofday(&now, NULL);
+ timeval_diff(&diff, &next, &now);
+
+ /* re-schedule the timer */
+ bsc_schedule_timer(&sgi->gtp_timer, diff.tv_sec, diff.tv_usec/1000);
+}
+
+/* timer callback for libgtp retransmissions and ping */
+static void sgsn_gtp_tmr_cb(void *data)
+{
+ struct sgsn_instance *sgi = data;
+
+ /* Do all the retransmissions as needed */
+ gtp_retrans(sgi->gsn);
+
+ sgsn_gtp_tmr_start(sgi);
+}
+
+int sgsn_gtp_init(struct sgsn_instance *sgi)
+{
+ int rc;
+ struct gsn_t *gsn;
+
+ rc = gtp_new(&sgi->gsn, sgi->cfg.gtp_statedir,
+ &sgi->cfg.gtp_listenaddr.sin_addr, GTP_MODE_SGSN);
+ if (rc) {
+ LOGP(DGPRS, LOGL_ERROR, "Failed to create GTP: %d\n", rc);
+ return rc;
+ }
+ gsn = sgi->gsn;
+
+ sgi->gtp_fd0.fd = gsn->fd0;
+ sgi->gtp_fd0.priv_nr = 0;
+ sgi->gtp_fd0.data = sgi;
+ sgi->gtp_fd0.cb = sgsn_gtp_fd_cb;
+ rc = bsc_register_fd(&sgi->gtp_fd0);
+ if (rc < 0)
+ return rc;
+
+ sgi->gtp_fd1c.fd = gsn->fd1c;
+ sgi->gtp_fd1c.priv_nr = 1;
+ sgi->gtp_fd1c.data = sgi;
+ sgi->gtp_fd1c.cb = sgsn_gtp_fd_cb;
+ bsc_register_fd(&sgi->gtp_fd1c);
+ if (rc < 0)
+ return rc;
+
+ sgi->gtp_fd1u.fd = gsn->fd1u;
+ sgi->gtp_fd1u.priv_nr = 2;
+ sgi->gtp_fd1u.data = sgi;
+ sgi->gtp_fd1u.cb = sgsn_gtp_fd_cb;
+ bsc_register_fd(&sgi->gtp_fd1u);
+ if (rc < 0)
+ return rc;
+
+ /* Start GTP re-transmission timer */
+ sgi->gtp_timer.cb = sgsn_gtp_tmr_cb;
+ sgsn_gtp_tmr_start(sgi);
+
+ /* Register callbackcs with libgtp */
+ gtp_set_cb_delete_context(gsn, cb_delete_context);
+ gtp_set_cb_conf(gsn, cb_conf);
+ gtp_set_cb_data_ind(gsn, cb_data_ind);
+ gtp_set_cb_unsup_ind(gsn, cb_unsup_ind);
+ gtp_set_cb_extheader_ind(gsn, cb_extheader_ind);
+
+ return 0;
+}