gprs_ns.h

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#pragma once

#include <stdint.h>

/* Our Implementation */
#include <netinet/in.h>
#include <osmocom/core/linuxlist.h>
#include <osmocom/core/msgb.h>
#include <osmocom/core/timer.h>
#include <osmocom/core/select.h>
#include <osmocom/gprs/gprs_msgb.h>

#include <osmocom/gprs/protocol/gsm_08_16.h>

#define NS_TIMERS_COUNT 7
#define NS_TIMERS "(tns-block|tns-block-retries|tns-reset|tns-reset-retries|tns-test|tns-alive|tns-alive-retries)"
#define NS_TIMERS_HELP  \
        "(un)blocking Timer (Tns-block) timeout\n"              \
        "(un)blocking Timer (Tns-block) number of retries\n"    \
        "Reset Timer (Tns-reset) timeout\n"                     \
        "Reset Timer (Tns-reset) number of retries\n"           \
        "Test Timer (Tns-test) timeout\n"                       \
        "Alive Timer (Tns-alive) timeout\n"                     \
        "Alive Timer (Tns-alive) number of retries\n"

/* Educated guess - LLC user payload is 1500 bytes plus possible headers */
#define NS_ALLOC_SIZE   3072
#define NS_ALLOC_HEADROOM 20

enum ns_timeout {
        NS_TOUT_TNS_BLOCK,
        NS_TOUT_TNS_BLOCK_RETRIES,
        NS_TOUT_TNS_RESET,
        NS_TOUT_TNS_RESET_RETRIES,
        NS_TOUT_TNS_TEST,
        NS_TOUT_TNS_ALIVE,
        NS_TOUT_TNS_ALIVE_RETRIES,
};

#define NSE_S_BLOCKED   0x0001
#define NSE_S_ALIVE     0x0002
#define NSE_S_RESET     0x0004

enum gprs_ns_ll {
        GPRS_NS_LL_UDP,         
        GPRS_NS_LL_E1,          
        GPRS_NS_LL_FR_GRE,      
};

enum gprs_ns_evt {
        GPRS_NS_EVT_UNIT_DATA,
};

enum gprs_ns_cs {
        GPRS_NS_CS_CREATED,     
        GPRS_NS_CS_FOUND,       
        GPRS_NS_CS_REJECTED,    
        GPRS_NS_CS_SKIPPED,     
        GPRS_NS_CS_ERROR,       
};

struct gprs_nsvc;
typedef int gprs_ns_cb_t(enum gprs_ns_evt event, struct gprs_nsvc *nsvc,
                         struct msgb *msg, uint16_t bvci);

struct gprs_ns_inst {
        gprs_ns_cb_t *cb;

        struct llist_head gprs_nsvcs;

        struct gprs_nsvc *unknown_nsvc;

        uint16_t timeout[NS_TIMERS_COUNT];

        struct {
                struct osmo_fd fd;
                uint32_t local_ip;
                uint16_t local_port;
                int dscp;
        } nsip;
        struct {
                struct osmo_fd fd;
                uint32_t local_ip;
                unsigned int enabled:1;
        } frgre;
};

enum nsvc_timer_mode {
        /* standard timers */
        NSVC_TIMER_TNS_TEST,
        NSVC_TIMER_TNS_ALIVE,
        NSVC_TIMER_TNS_RESET,
        _NSVC_TIMER_NR,
};

struct gprs_nsvc {
        struct llist_head list;
        struct gprs_ns_inst *nsi;

        uint16_t nsei;  
        uint16_t nsvci; 
        uint32_t state;
        uint32_t remote_state;

        struct osmo_timer_list timer;
        enum nsvc_timer_mode timer_mode;
        struct timeval timer_started;
        int alive_retries;

        unsigned int remote_end_is_sgsn:1;
        unsigned int persistent:1;
        unsigned int nsvci_is_valid:1;

        struct rate_ctr_group *ctrg;
        struct osmo_stat_item_group *statg;

        enum gprs_ns_ll ll;

        union {
                struct {
                        struct sockaddr_in bts_addr;
                } ip;
                struct {
                        struct sockaddr_in bts_addr;
                } frgre;
        };
};

/* Create a new NS protocol instance */
struct gprs_ns_inst *gprs_ns_instantiate(gprs_ns_cb_t *cb, void *ctx);

/* Close a NS protocol instance */
void gprs_ns_close(struct gprs_ns_inst *nsi);

/* Close and Destroy a NS protocol instance */
void gprs_ns_destroy(struct gprs_ns_inst *nsi);

/* Listen for incoming GPRS packets via NS/UDP */
int gprs_ns_nsip_listen(struct gprs_ns_inst *nsi);

/* Establish a connection (from the BSS) to the SGSN */
struct gprs_nsvc *gprs_ns_nsip_connect(struct gprs_ns_inst *nsi,
                                        struct sockaddr_in *dest,
                                        uint16_t nsei, uint16_t nsvci);


struct sockaddr_in;

/* main function for higher layers (BSSGP) to send NS messages */
int gprs_ns_sendmsg(struct gprs_ns_inst *nsi, struct msgb *msg);

int gprs_ns_tx_reset(struct gprs_nsvc *nsvc, uint8_t cause);
int gprs_ns_tx_block(struct gprs_nsvc *nsvc, uint8_t cause);
int gprs_ns_tx_unblock(struct gprs_nsvc *nsvc);

/* Listen for incoming GPRS packets via NS/FR/GRE */
int gprs_ns_frgre_listen(struct gprs_ns_inst *nsi);

struct gprs_nsvc *gprs_nsvc_create(struct gprs_ns_inst *nsi, uint16_t nsvci);
void gprs_nsvc_delete(struct gprs_nsvc *nsvc);
struct gprs_nsvc *gprs_nsvc_by_nsei(struct gprs_ns_inst *nsi, uint16_t nsei);
struct gprs_nsvc *gprs_nsvc_by_nsvci(struct gprs_ns_inst *nsi, uint16_t nsvci);

/* Initiate a RESET procedure (including timer start, ...)*/
int gprs_nsvc_reset(struct gprs_nsvc *nsvc, uint8_t cause);

/* Add NS-specific VTY stuff */
int gprs_ns_vty_init(struct gprs_ns_inst *nsi);

/* Resturn peer info as string (NOTE: the buffer is allocated statically) */
const char *gprs_ns_ll_str(struct gprs_nsvc *nsvc);

/* Copy the link layer info from other into nsvc */
void gprs_ns_ll_copy(struct gprs_nsvc *nsvc, struct gprs_nsvc *other);

/* Clear the link layer info (will never match a real link then) */
void gprs_ns_ll_clear(struct gprs_nsvc *nsvc);

struct msgb *gprs_ns_msgb_alloc(void);

enum signal_ns {
        S_NS_RESET,
        S_NS_BLOCK,
        S_NS_UNBLOCK,
        S_NS_ALIVE_EXP, /* Tns-alive expired more than N times */
        S_NS_REPLACED, /* nsvc object is replaced (sets old_nsvc) */
        S_NS_MISMATCH, /* got an unexpected IE (sets msg, pdu_type, ie_type) */
};

extern const struct value_string gprs_ns_signal_ns_names[];

struct ns_signal_data {
        struct gprs_nsvc *nsvc;
        struct gprs_nsvc *old_nsvc;
        uint8_t cause;
        uint8_t pdu_type;
        uint8_t ie_type;
        struct msgb *msg;
};

void gprs_ns_set_log_ss(int ss);