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Jacob Erlbeck jerlbeck at sysmocom.deThis patch refactors gprs_ns_rcvmsg() by moving the parts relevant to
the NS messages into the new functions gprs_ns_vc_create() (nsvc
object creation) and gprs_ns_process_msg() (main NS automaton). These
do not contain code that directly depends on the link layer (they
call other functions that still do). This reduces the gprs_ns_rcvmsg()
function to calling these two functions and optionally setting up the
link layer specific fields of the nsvc.
---
include/osmocom/gprs/gprs_ns.h | 9 ++
src/gb/gprs_ns.c | 193 ++++++++++++++++++++++++++++------------
2 files changed, 146 insertions(+), 56 deletions(-)
diff --git a/include/osmocom/gprs/gprs_ns.h b/include/osmocom/gprs/gprs_ns.h
index 8ca5a88..c709312 100644
--- a/include/osmocom/gprs/gprs_ns.h
+++ b/include/osmocom/gprs/gprs_ns.h
@@ -49,6 +49,15 @@ enum gprs_ns_evt {
GPRS_NS_EVT_UNIT_DATA,
};
+/*! \brief Osmocom NS VC create status */
+enum gprs_ns_cs {
+ GPRS_NS_CS_CREATED, /*!< A NSVC object has been created */
+ GPRS_NS_CS_FOUND, /*!< A NSVC object has been found */
+ GPRS_NS_CS_REJECTED, /*!< Rejected and answered message */
+ GPRS_NS_CS_SKIPPED, /*!< Skipped message */
+ GPRS_NS_CS_ERROR, /*!< Failed to process message */
+};
+
struct gprs_nsvc;
/*! \brief Osmocom GPRS callback function type */
typedef int gprs_ns_cb_t(enum gprs_ns_evt event, struct gprs_nsvc *nsvc,
diff --git a/src/gb/gprs_ns.c b/src/gb/gprs_ns.c
index 5620b3a..e41c118 100644
--- a/src/gb/gprs_ns.c
+++ b/src/gb/gprs_ns.c
@@ -730,6 +730,13 @@ static int gprs_ns_rx_block(struct gprs_nsvc *nsvc, struct msgb *msg)
return gprs_ns_tx_simple(nsvc, NS_PDUT_BLOCK_ACK);
}
+int gprs_ns_vc_create(struct gprs_ns_inst *nsi, struct msgb *msg,
+ struct gprs_nsvc *fallback_nsvc,
+ struct gprs_nsvc **new_nsvc);
+
+int gprs_ns_process_msg(struct gprs_ns_inst *nsi, struct msgb *msg,
+ struct gprs_nsvc *nsvc);
+
/*! \brief Receive incoming NS message from underlying transport layer
* \param nsi NS instance to which the data belongs
* \param[in] msg message buffer containing newly-received data
@@ -743,72 +750,146 @@ static int gprs_ns_rx_block(struct gprs_nsvc *nsvc, struct msgb *msg)
int gprs_ns_rcvmsg(struct gprs_ns_inst *nsi, struct msgb *msg,
struct sockaddr_in *saddr, enum gprs_ns_ll ll)
{
- struct gprs_ns_hdr *nsh = (struct gprs_ns_hdr *) msg->l2h;
struct gprs_nsvc *nsvc;
int rc = 0;
/* look up the NSVC based on source address */
nsvc = nsvc_by_rem_addr(nsi, saddr);
+
if (!nsvc) {
- struct tlv_parsed tp;
- uint16_t nsei;
- if (nsh->pdu_type == NS_PDUT_STATUS) {
- LOGP(DNS, LOGL_INFO, "Ignoring NS STATUS from %s:%u "
- "for non-existing NS-VC\n",
- inet_ntoa(saddr->sin_addr), ntohs(saddr->sin_port));
- return 0;
- }
- /* Only the RESET procedure creates a new NSVC */
- if (nsh->pdu_type != NS_PDUT_RESET) {
- /* Since we have no NSVC, we have to use a fake */
- nsvc = nsi->unknown_nsvc;
- log_set_context(GPRS_CTX_NSVC, nsvc);
- LOGP(DNS, LOGL_INFO, "Rejecting NS PDU type 0x%0x "
- "from %s:%u for non-existing NS-VC\n",
- nsh->pdu_type, inet_ntoa(saddr->sin_addr),
- ntohs(saddr->sin_port));
- nsvc->nsvci = nsvc->nsei = 0xfffe;
- nsvc->ip.bts_addr = *saddr;
- nsvc->state = NSE_S_ALIVE;
+ struct gprs_nsvc *fallback_nsvc;
+
+ fallback_nsvc = nsi->unknown_nsvc;
+ log_set_context(GPRS_CTX_NSVC, fallback_nsvc);
+ fallback_nsvc->ip.bts_addr = *saddr;
+ fallback_nsvc->ll = ll;
+
+ rc = gprs_ns_vc_create(nsi, msg, fallback_nsvc, &nsvc);
+
+ switch (rc) {
+ case GPRS_NS_CS_CREATED:
+ case GPRS_NS_CS_FOUND:
nsvc->ll = ll;
-#if 0
- return gprs_ns_tx_reset(nsvc, NS_CAUSE_PDU_INCOMP_PSTATE);
-#else
- return gprs_ns_tx_status(nsvc,
- NS_CAUSE_PDU_INCOMP_PSTATE, 0,
- msg);
-#endif
- }
- rc = tlv_parse(&tp, &ns_att_tlvdef, nsh->data,
- msgb_l2len(msg) - sizeof(*nsh), 0, 0);
- if (rc < 0) {
- LOGP(DNS, LOGL_ERROR, "Rx NS RESET Error %d during "
- "TLV Parse\n", rc);
+ break;
+ case GPRS_NS_CS_SKIPPED:
+ case GPRS_NS_CS_REJECTED:
+ break;
+ default:
return rc;
}
- if (!TLVP_PRESENT(&tp, NS_IE_CAUSE) ||
- !TLVP_PRESENT(&tp, NS_IE_VCI) ||
- !TLVP_PRESENT(&tp, NS_IE_NSEI)) {
- LOGP(DNS, LOGL_ERROR, "NS RESET Missing mandatory IE\n");
- gprs_ns_tx_status(nsvc, NS_CAUSE_MISSING_ESSENT_IE, 0,
- msg);
- return -EINVAL;
- }
- nsei = ntohs(*(uint16_t *)TLVP_VAL(&tp, NS_IE_NSEI));
- /* Check if we already know this NSEI, the remote end might
- * simply have changed addresses, or it is a SGSN */
- nsvc = gprs_nsvc_by_nsei(nsi, nsei);
- if (!nsvc) {
- nsvc = gprs_nsvc_create(nsi, 0xffff);
- nsvc->ll = ll;
- log_set_context(GPRS_CTX_NSVC, nsvc);
- LOGP(DNS, LOGL_INFO, "Creating NS-VC for BSS at %s:%u\n",
- inet_ntoa(saddr->sin_addr), ntohs(saddr->sin_port));
- }
- /* Update the remote peer IP address/port */
+
+ rc = 0;
+ }
+
+ if (nsvc) {
nsvc->ip.bts_addr = *saddr;
- } else
- msgb_nsei(msg) = nsvc->nsei;
+ rc = gprs_ns_process_msg(nsi, msg, nsvc);
+ }
+
+ return rc;
+}
+
+const char *gprs_ns_format_peer(struct gprs_nsvc *nsvc)
+{
+ static char buf[80];
+ snprintf(buf, sizeof(buf), "%s:%u",
+ inet_ntoa(nsvc->ip.bts_addr.sin_addr),
+ ntohs(nsvc->ip.bts_addr.sin_port));
+
+ return buf;
+}
+
+/*! \brief Create/get NS-VC independently from underlying transport layer
+ * \param nsi NS instance to which the data belongs
+ * \param[in] msg message buffer containing newly-received data
+ * \param[in] fallback_nsvc is used to send error messages back to the peer
+ * \param[out] new_nsvc contains a pointer to a NS-VC object if one has
+ * been created or found
+ * \returns < 0 in case of error, GPRS_NS_CS_SKIPPED if a message has been
+ * skipped, GPRS_NS_CS_REJECTED if a message has been rejected and
+ * answered accordingly, GPRS_NS_CS_CREATED if a new NS-VC object
+ * has been created and registered, and GPRS_NS_CS_FOUND if an
+ * existing NS-VC object has been found with the same NSEI.
+ *
+ * This contains the initial NS automaton state (NS-VC not yet attached).
+ */
+int gprs_ns_vc_create(struct gprs_ns_inst *nsi, struct msgb *msg,
+ struct gprs_nsvc *fallback_nsvc,
+ struct gprs_nsvc **new_nsvc)
+{
+ struct gprs_ns_hdr *nsh = (struct gprs_ns_hdr *)msg->l2h;
+ struct gprs_nsvc *existing_nsvc;
+
+ struct tlv_parsed tp;
+ uint16_t nsei;
+
+ int rc;
+
+ if (nsh->pdu_type == NS_PDUT_STATUS) {
+ LOGP(DNS, LOGL_INFO, "Ignoring NS STATUS from %s "
+ "for non-existing NS-VC\n",
+ gprs_ns_format_peer(fallback_nsvc));
+ return GPRS_NS_CS_SKIPPED;
+ }
+ /* Only the RESET procedure creates a new NSVC */
+ if (nsh->pdu_type != NS_PDUT_RESET) {
+ /* Since we have no NSVC, we have to use a fake */
+ log_set_context(GPRS_CTX_NSVC, fallback_nsvc);
+ LOGP(DNS, LOGL_INFO, "Rejecting NS PDU type 0x%0x "
+ "from %s for non-existing NS-VC\n",
+ nsh->pdu_type, gprs_ns_format_peer(fallback_nsvc));
+ fallback_nsvc->nsvci = fallback_nsvc->nsei = 0xfffe;
+ fallback_nsvc->state = NSE_S_ALIVE;
+
+ return gprs_ns_tx_status(fallback_nsvc,
+ NS_CAUSE_PDU_INCOMP_PSTATE, 0, msg);
+ }
+ rc = tlv_parse(&tp, &ns_att_tlvdef, nsh->data,
+ msgb_l2len(msg) - sizeof(*nsh), 0, 0);
+ if (rc < 0) {
+ LOGP(DNS, LOGL_ERROR, "Rx NS RESET Error %d during "
+ "TLV Parse\n", rc);
+ return rc;
+ }
+ if (!TLVP_PRESENT(&tp, NS_IE_CAUSE) ||
+ !TLVP_PRESENT(&tp, NS_IE_VCI) || !TLVP_PRESENT(&tp, NS_IE_NSEI)) {
+ LOGP(DNS, LOGL_ERROR, "NS RESET Missing mandatory IE\n");
+ gprs_ns_tx_status(fallback_nsvc, NS_CAUSE_MISSING_ESSENT_IE, 0,
+ msg);
+ return -EINVAL;
+ }
+ nsei = ntohs(*(uint16_t *) TLVP_VAL(&tp, NS_IE_NSEI));
+ /* Check if we already know this NSEI, the remote end might
+ * simply have changed addresses, or it is a SGSN */
+ existing_nsvc = gprs_nsvc_by_nsei(nsi, nsei);
+ if (!existing_nsvc) {
+ *new_nsvc = gprs_nsvc_create(nsi, 0xffff);
+ log_set_context(GPRS_CTX_NSVC, *new_nsvc);
+ LOGP(DNS, LOGL_INFO, "Creating NS-VC for BSS at %s\n",
+ gprs_ns_format_peer(fallback_nsvc));
+
+ return GPRS_NS_CS_CREATED;
+ }
+
+ *new_nsvc = existing_nsvc;
+ return GPRS_NS_CS_FOUND;
+}
+
+/*! \brief Process NS message independently from underlying transport layer
+ * \param nsi NS instance to which the data belongs
+ * \param[in] msg message buffer containing newly-received data
+ * \param[in] nsvc refers to the virtual connection
+ * \returns 0 in case of success, < 0 in case of error
+ *
+ * This contains the main NS automaton.
+ */
+int gprs_ns_process_msg(struct gprs_ns_inst *nsi, struct msgb *msg,
+ struct gprs_nsvc *nsvc)
+{
+ struct gprs_ns_hdr *nsh = (struct gprs_ns_hdr *) msg->l2h;
+ int rc = 0;
+
+ msgb_nsei(msg) = nsvc->nsei;
log_set_context(GPRS_CTX_NSVC, nsvc);
--
1.7.9.5