1 files changed, 375 insertions, 0 deletions
diff --git a/src/gb/gprs_ns_sns.c b/src/gb/gprs_ns_sns.c
new file mode 100644
index 00000000..ddd641f8
--- /dev/null
+++ b/src/gb/gprs_ns_sns.c
@@ -0,0 +1,375 @@
+/* Implementation of 3GPP TS 48.016 NS IP Sub-Network Service */
+/* (C) 2018 by Harald Welte <laforge@gnumonks.org> */
+
+/* The BSS NSE only has one SGSN IP address configured, and it will use the SNS procedures
+ * to communicated its local IPs/ports as well as all the SGSN side IPs/ports and
+ * associated weights.  In theory, the BSS then uses this to establish a full mesh
+ * of NSVCs between all BSS-side IPs/ports and SGSN-side IPs/ports */
+
+#include <errno.h>
+
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#include <osmocom/core/fsm.h>
+#include <osmocom/core/msgb.h>
+#include <osmocom/core/signal.h>
+#include <osmocom/core/socket.h>
+#include <osmocom/gsm/tlv.h>
+#include <osmocom/gprs/gprs_msgb.h>
+#include <osmocom/gprs/gprs_ns.h>
+
+#include "common_vty.h"
+#include "gb_internal.h"
+
+#define S(x)	(1 << (x))
+
+struct gprs_sns_state {
+	struct gprs_ns_inst *nsi;
+	struct gprs_nsvc *nsvc_hack;
+
+	/* local configuration to send to the remote end */
+	struct gprs_ns_ie_ip4_elem *ip4_local;
+	size_t num_ip4_local;
+
+	/* remote configuration as received */
+	struct gprs_ns_ie_ip4_elem *ip4_remote;
+	unsigned int num_ip4_remote;
+};
+
+static inline struct gprs_ns_inst *ns_inst_from_fi(struct osmo_fsm_inst *fi)
+{
+	struct gprs_sns_state *gss = (struct gprs_sns_state *) fi->priv;
+	return gss->nsi;
+}
+
+/***********************************************************************
+ * BSS-side FSM for IP Sub-Network Service
+ ***********************************************************************/
+
+enum gprs_sns_bss_state {
+	GPRS_SNS_ST_UNCONFIGURED,
+	GPRS_SNS_ST_SIZE,		/*!< SNS-SIZE procedure ongoing */
+	GPRS_SNS_ST_CONFIG_BSS,		/*!< SNS-CONFIG procedure (BSS->SGSN) ongoing */
+	GPRS_SNS_ST_CONFIG_SGSN,	/*!< SNS-CONFIG procedure (SGSN->BSS) ongoing */
+	GPRS_SNS_ST_CONFIGURED,
+};
+
+enum gprs_sns_event {
+	GPRS_SNS_EV_START,
+	GPRS_SNS_EV_SIZE,
+	GPRS_SNS_EV_SIZE_ACK,
+	GPRS_SNS_EV_CONFIG,
+	GPRS_SNS_EV_CONFIG_END,		/*!< SNS-CONFIG with end flag received */
+	GPRS_SNS_EV_CONFIG_ACK,
+};
+
+static const struct value_string gprs_sns_event_names[] = {
+	{ GPRS_SNS_EV_START, 		"START" },
+	{ GPRS_SNS_EV_SIZE,		"SIZE" },
+	{ GPRS_SNS_EV_SIZE_ACK,		"SIZE_ACK" },
+	{ GPRS_SNS_EV_CONFIG,		"CONFIG" },
+	{ GPRS_SNS_EV_CONFIG_END,	"CONFIG_END" },
+	{ GPRS_SNS_EV_CONFIG_ACK,	"CONFIG_ACK" },
+	{ 0, NULL }
+};
+
+static void gprs_sns_st_unconfigured(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	struct gprs_ns_inst *nsi = ns_inst_from_fi(fi);
+	switch (event) {
+	case GPRS_SNS_EV_START:
+		osmo_fsm_inst_state_chg(fi, GPRS_SNS_ST_SIZE, nsi->timeout[NS_TOUT_TSNS_PROV], 1);
+		break;
+	default:
+		OSMO_ASSERT(0);
+	}
+}
+
+static void gprs_sns_st_size(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	struct gprs_ns_inst *nsi = ns_inst_from_fi(fi);
+	struct tlv_parsed *tp = NULL;
+
+	switch (event) {
+	case GPRS_SNS_EV_SIZE_ACK:
+		tp = data;
+		if (TLVP_VAL_MINLEN(tp, NS_IE_CAUSE, 1)) {
+			LOGPFSML(fi, LOGL_ERROR, "SNS-SIZE-ACK with cause %s\n",
+				 gprs_ns_cause_str(*TLVP_VAL(tp, NS_IE_CAUSE)));
+		} else {
+			osmo_fsm_inst_state_chg(fi, GPRS_SNS_ST_CONFIG_BSS,
+						nsi->timeout[NS_TOUT_TSNS_PROV], 2);
+		}
+		break;
+	default:
+		OSMO_ASSERT(0);
+	}
+}
+static void gprs_sns_st_size_onenter(struct osmo_fsm_inst *fi, uint32_t old_state)
+{
+	struct gprs_sns_state *gss = (struct gprs_sns_state *) fi->priv;
+	uint16_t num = gss->num_ip4_local;
+
+	gprs_ns_tx_sns_size(gss->nsvc_hack, true, num, &num, NULL);
+}
+
+
+static void gprs_sns_st_config_bss(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	//struct gprs_sns_state *gss = (struct gprs_sns_state *) fi->priv;
+	//struct gprs_ns_inst *nsi = ns_inst_from_fi(fi);
+	struct tlv_parsed *tp = NULL;
+
+	switch (event) {
+	case GPRS_SNS_EV_CONFIG_ACK:
+		tp = data;
+		if (TLVP_VAL_MINLEN(tp, NS_IE_CAUSE, 1)) {
+			LOGPFSML(fi, LOGL_ERROR, "SNS-CONFIG-ACK with cause %s\n",
+				 gprs_ns_cause_str(*TLVP_VAL(tp, NS_IE_CAUSE)));
+		} else {
+			osmo_fsm_inst_state_chg(fi, GPRS_SNS_ST_CONFIG_SGSN, 0, 0);
+		}
+		break;
+	default:
+		OSMO_ASSERT(0);
+	}
+}
+static void gprs_sns_st_config_bss_onenter(struct osmo_fsm_inst *fi, uint32_t old_state)
+{
+	struct gprs_sns_state *gss = (struct gprs_sns_state *) fi->priv;
+	/* Transmit SNS-CONFIG */
+	gprs_ns_tx_sns_config(gss->nsvc_hack, true, gss->ip4_local, gss->num_ip4_local);
+}
+
+static void gprs_sns_st_config_sgsn(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	struct gprs_sns_state *gss = (struct gprs_sns_state *) fi->priv;
+	struct tlv_parsed *tp = NULL;
+
+	switch (event) {
+	case GPRS_SNS_EV_CONFIG_END:
+	case GPRS_SNS_EV_CONFIG:
+		tp = data;
+#if 0		/* part of incoming SNS-SIZE (doesn't happen on BSS side */
+		if (TLVP_PRESENT(tp, NS_IE_RESET_FLAG)) {
+			/* reset all existing config */
+			if (gss->ip4_remote)
+				talloc_free(gss->ip4_remote);
+			gss->num_ip4_remote = 0;
+		}
+#endif
+		if (TLVP_PRESENT(tp, NS_IE_IPv4_LIST)) {
+			const struct gprs_ns_ie_ip4_elem *v4_list;
+			unsigned int num_v4;
+			v4_list = (const struct gprs_ns_ie_ip4_elem *) TLVP_VAL(tp, NS_IE_IPv4_LIST);
+			num_v4 = TLVP_LEN(tp, NS_IE_IPv4_LIST) / sizeof(*v4_list);
+			/* realloc to the new size */
+			gss->ip4_remote = talloc_realloc(gss, gss->ip4_remote,
+							 struct gprs_ns_ie_ip4_elem,
+							 gss->num_ip4_remote+num_v4);
+			/* append the new entries to the end of the list */
+			memcpy(&gss->ip4_remote[gss->num_ip4_remote], v4_list, num_v4);
+			gss->num_ip4_remote += num_v4;
+		} else {
+			uint8_t cause = NS_CAUSE_INVAL_NR_IPv4_EP;
+			gprs_ns_tx_sns_config_ack(gss->nsvc_hack, &cause);
+			/* state change? */
+		}
+		LOGPFSML(fi, LOGL_INFO, "Rx SNS-CONFIG: Remote IPv4 list now %u entries\n",
+			 gss->num_ip4_remote);
+		if (event == GPRS_SNS_EV_CONFIG_END) {
+			osmo_fsm_inst_state_chg(fi, GPRS_SNS_ST_CONFIGURED, 0, 0);
+		}
+		/* send CONFIG-ACK */
+		gprs_ns_tx_sns_config_ack(gss->nsvc_hack, NULL);
+		break;
+	default:
+		OSMO_ASSERT(0);
+	}
+}
+
+static void gprs_sns_st_configured(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	/* FIXME: ADD/DELETE procedures */
+}
+
+static void gprs_sns_st_configured_onenter(struct osmo_fsm_inst *fi, uint32_t old_state)
+{
+	struct ns_signal_data nssd = {0};
+	osmo_signal_dispatch(SS_L_NS, S_SNS_CONFIGURED, &nssd);
+}
+
+static const struct osmo_fsm_state gprs_sns_bss_states[] = {
+	[GPRS_SNS_ST_UNCONFIGURED] = {
+		.in_event_mask = S(GPRS_SNS_EV_START),
+		.out_state_mask = S(GPRS_SNS_ST_SIZE),
+		.name = "UNCONFIGURED",
+		.action = gprs_sns_st_unconfigured,
+	},
+	[GPRS_SNS_ST_SIZE] = {
+		.in_event_mask = S(GPRS_SNS_EV_SIZE_ACK),
+		.out_state_mask = S(GPRS_SNS_ST_UNCONFIGURED) |
+				  S(GPRS_SNS_ST_SIZE) |
+				  S(GPRS_SNS_ST_CONFIG_BSS),
+		.name = "SIZE",
+		.action = gprs_sns_st_size,
+		.onenter = gprs_sns_st_size_onenter,
+	},
+	[GPRS_SNS_ST_CONFIG_BSS] = {
+		.in_event_mask = S(GPRS_SNS_EV_CONFIG_ACK),
+		.out_state_mask = S(GPRS_SNS_ST_UNCONFIGURED) |
+				  S(GPRS_SNS_ST_CONFIG_BSS) |
+				  S(GPRS_SNS_ST_CONFIG_SGSN),
+		.name = "CONFIG_BSS",
+		.action = gprs_sns_st_config_bss,
+		.onenter = gprs_sns_st_config_bss_onenter,
+	},
+	[GPRS_SNS_ST_CONFIG_SGSN] = {
+		.in_event_mask = S(GPRS_SNS_EV_CONFIG) |
+				 S(GPRS_SNS_EV_CONFIG_END),
+		.out_state_mask = S(GPRS_SNS_ST_UNCONFIGURED) |
+				  S(GPRS_SNS_ST_CONFIG_SGSN) |
+				  S(GPRS_SNS_ST_CONFIGURED),
+		.name = "CONFIG_SGSN",
+		.action = gprs_sns_st_config_sgsn,
+	},
+	[GPRS_SNS_ST_CONFIGURED] = {
+		//.in_event_mask = S(),
+		.out_state_mask = S(GPRS_SNS_ST_UNCONFIGURED),
+		.name = "CONFIGURED",
+		.action = gprs_sns_st_configured,
+		.onenter = gprs_sns_st_configured_onenter,
+	},
+};
+
+static int gprs_sns_fsm_bss_timer_cb(struct osmo_fsm_inst *fi)
+{
+	struct gprs_ns_inst *nsi = ns_inst_from_fi(fi);
+
+	switch (fi->T) {
+	case 1:
+		osmo_fsm_inst_state_chg(fi, GPRS_SNS_ST_SIZE, nsi->timeout[NS_TOUT_TSNS_PROV], 1);
+		break;
+	case 2:
+		osmo_fsm_inst_state_chg(fi, GPRS_SNS_ST_CONFIG_BSS, nsi->timeout[NS_TOUT_TSNS_PROV], 2);
+		break;
+	}
+	return 0;
+}
+
+static struct osmo_fsm gprs_sns_bss_fsm = {
+	.name = "GPRS-SNS-BSS",
+	.states = gprs_sns_bss_states,
+	.num_states = ARRAY_SIZE(gprs_sns_bss_states),
+	.allstate_event_mask = 0,
+	.allstate_action = NULL,
+	.cleanup = NULL,
+	.timer_cb = gprs_sns_fsm_bss_timer_cb,
+	/* .log_subsys = DNS, "is not constant" */
+	.event_names = gprs_sns_event_names,
+	.pre_term = NULL,
+};
+
+struct osmo_fsm_inst *gprs_sns_bss_fsm_start(void *ctx, struct gprs_nsvc *nsvc,
+					     const char *id)
+{
+	struct osmo_fsm_inst *fi;
+	struct gprs_sns_state *gss;
+	struct gprs_ns_ie_ip4_elem *ip4;
+	struct gprs_ns_inst *nsi = nsvc->nsi;
+
+	fi = osmo_fsm_inst_alloc(&gprs_sns_bss_fsm, ctx, NULL, LOGL_DEBUG, id);
+	if (!fi)
+		return fi;
+
+	gss = talloc_zero(fi, struct gprs_sns_state);
+	if (!gss)
+		goto err;
+
+	fi->priv = gss;
+	gss->nsi = nsi;
+	/* FIXME: we shouldn't use 'nsvc' here but only gprs_ns_inst */
+	gss->nsvc_hack = nsvc;
+
+	/* create IPv4 list from the one IP/port the NS instance has */
+	ip4 = talloc_zero(gss, struct gprs_ns_ie_ip4_elem);
+	if (!ip4)
+		goto err;
+	if (nsi->nsip.local_ip)
+		ip4->ip_addr = htonl(nsi->nsip.local_ip);
+	else {
+		/* unspecified local address. Figure out which address the kernel would use if we
+		 * wanted to send a packet to the remote_ip */
+		char local_ip[32];
+		struct in_addr in = { .s_addr = htonl(nsi->nsip.remote_ip) };
+		osmo_sock_local_ip(local_ip, inet_ntoa(in));
+		ip4->ip_addr = inet_addr(local_ip);
+	}
+	ip4->udp_port = htons(gss->nsi->nsip.local_port);
+	ip4->sig_weight = 2;
+	ip4->data_weight = 1;
+	gss->ip4_local = ip4;
+	gss->num_ip4_local = 1;
+
+	/* start the FSM */
+	osmo_fsm_inst_dispatch(fi, GPRS_SNS_EV_START, NULL);
+
+	return fi;
+err:
+	osmo_fsm_inst_term(fi, OSMO_FSM_TERM_ERROR, NULL);
+	return NULL;
+}
+
+
+/* main entry point for receiving SNS messages from the network */
+int gprs_ns_rx_sns(struct gprs_ns_inst *nsi, struct msgb *msg, struct tlv_parsed *tp)
+{
+	struct gprs_ns_hdr *nsh = (struct gprs_ns_hdr *) msg->l2h;
+	uint16_t nsei = msgb_nsei(msg);
+	struct osmo_fsm_inst *fi;
+
+	LOGP(DNS, LOGL_DEBUG, "NSEI=%u Rx SNS PDU type %s\n", nsei,
+		get_value_string(gprs_ns_pdu_strings, nsh->pdu_type));
+
+	/* FIXME: how to resolve SNS FSM Instance by NSEI (SGSN)? */
+	fi = nsi->bss_sns_fi;
+
+	switch (nsh->pdu_type) {
+	case SNS_PDUT_SIZE:
+		osmo_fsm_inst_dispatch(fi, GPRS_SNS_EV_SIZE, tp);
+		break;
+	case SNS_PDUT_SIZE_ACK:
+		osmo_fsm_inst_dispatch(fi, GPRS_SNS_EV_SIZE_ACK, tp);
+		break;
+	case SNS_PDUT_CONFIG:
+		if (nsh->data[0] & 0x01)
+			osmo_fsm_inst_dispatch(fi, GPRS_SNS_EV_CONFIG_END, tp);
+		else
+			osmo_fsm_inst_dispatch(fi, GPRS_SNS_EV_CONFIG, tp);
+		break;
+	case SNS_PDUT_CONFIG_ACK:
+		osmo_fsm_inst_dispatch(fi, GPRS_SNS_EV_CONFIG_ACK, tp);
+		break;
+	case SNS_PDUT_ACK:
+	case SNS_PDUT_ADD:
+	case SNS_PDUT_DELETE:
+	case SNS_PDUT_CHANGE_WEIGHT:
+		LOGP(DNS, LOGL_NOTICE, "NSEI=%u Rx unsupported SNS PDU type %s\n", nsei,
+			get_value_string(gprs_ns_pdu_strings, nsh->pdu_type));
+		break;
+	default:
+		LOGP(DNS, LOGL_ERROR, "NSEI=%u Rx unknown SNS PDU type %s\n", nsei,
+			get_value_string(gprs_ns_pdu_strings, nsh->pdu_type));
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+int gprs_sns_init(void)
+{
+	/* "DNS" is not a constant/#define, but an integer variable set by the client app */
+	gprs_sns_bss_fsm.log_subsys = DNS;
+	return osmo_fsm_register(&gprs_sns_bss_fsm);
+}