vjhc.h

/*NB_REVISION*/
 
/*NB_COPYRIGHT*/
#ifndef NB_VJHC_H
#define NB_VJHC_H
 
#include <ip.h>
const int VJHC_MAX_HDR = 128;       /* max TCP+IP hdr length (by protocol def) */
const uint8_t VJHC_MAX_STATES = 16; /* must be >2 and <255 */
/*
 * "state" data for each active tcp conversation on the wire.  This is
 * basically a copy of the entire IP/TCP header from the last packet together
 * with a small identifier the transmit & receive ends of the line use to
 * locate saved header.
 */
 
typedef struct
{
    beuint16_t th_sport;
    beuint16_t th_dport;
    beuint32_t th_seq;
    beuint32_t th_ack;
    uint8_t th_len;
    uint8_t th_flags;
    beuint16_t th_win;
    beuint16_t th_sum;
    beuint16_t th_urp;
} __attribute__((packed)) vjtcphdr;
 
inline vjtcphdr *GetVJTcpHdrFromIp(IPPKT *pIp)
{
    uint32_t hlen = (pIp->bVerHdrLen & 0x0F);
    return (vjtcphdr *)(((puint32_t)(pIp)) + hlen);
}
 
struct __attribute__((packed)) cstate
{
    beuint16_t cs_hlen; /* size of hdr (receive only) */
    uint8_t cs_id;      /* connection # associated with this state */
    uint8_t cs_filler;
 
    union __attribute__((packed))
    {
        IPPKT csu_ip; /* ip/tcp hdr from most recent packet */
        char extra[VJHC_MAX_HDR];
    };
 
    void Clear();
    bool Match(IPPKT *pIp);
    vjtcphdr *GetHdr();
};
 
#define cs_hdr (char *)&csu_ip
#define cs_ip csu_ip
 
class slcompress
{
   private:
    int last_tsn;      /* most recently used tstate */
    uint8_t last_recv; /* last rcvd conn. id */
    uint8_t last_xmit; /* last sent conn. id */
    beuint16_t flags;
    struct cstate tstate[VJHC_MAX_STATES]; /* xmit connection states */
    struct cstate rstate[VJHC_MAX_STATES]; /* receive connection states */
   public:
    volatile int NumStatesRX;
    volatile int NumStatesTX;
 
    uint8_t compress_tcp(uint8_t *&pData, int &data_len, int compress_cid);
    PoolPtr uncompress_tcp(PoolPtr p, uint8_t *bufp, int len, uint32_t type);
    void init();
};
 
#endif