packet.h

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/* packet.h: Rx packet layout and definitions
 *
 * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([email protected])
 *
 * 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.
 */

#ifndef _LINUX_RXRPC_PACKET_H
#define _LINUX_RXRPC_PACKET_H

typedef u32 rxrpc_seq_t;    /* Rx message sequence number */
typedef u32 rxrpc_serial_t; /* Rx message serial number */
typedef __be32  rxrpc_seq_net_t; /* on-the-wire Rx message sequence number */
typedef __be32  rxrpc_serial_net_t; /* on-the-wire Rx message serial number */

/*****************************************************************************/
/*
 * on-the-wire Rx packet header
 * - all multibyte fields should be in network byte order
 */
struct rxrpc_header {
    __be32      epoch;      /* client boot timestamp */

    __be32      cid;        /* connection and channel ID */
#define RXRPC_MAXCALLS      4           /* max active calls per conn */
#define RXRPC_CHANNELMASK   (RXRPC_MAXCALLS-1)  /* mask for channel ID */
#define RXRPC_CIDMASK       (~RXRPC_CHANNELMASK)    /* mask for connection ID */
#define RXRPC_CIDSHIFT      ilog2(RXRPC_MAXCALLS)   /* shift for connection ID */
#define RXRPC_CID_INC       (1 << RXRPC_CIDSHIFT)   /* connection ID increment */

    __be32      callNumber; /* call ID (0 for connection-level packets) */
#define RXRPC_PROCESS_MAXCALLS  (1<<2)  /* maximum number of active calls per conn (power of 2) */

    __be32      seq;        /* sequence number of pkt in call stream */
    __be32      serial;     /* serial number of pkt sent to network */

    uint8_t     type;       /* packet type */
#define RXRPC_PACKET_TYPE_DATA      1   /* data */
#define RXRPC_PACKET_TYPE_ACK       2   /* ACK */
#define RXRPC_PACKET_TYPE_BUSY      3   /* call reject */
#define RXRPC_PACKET_TYPE_ABORT     4   /* call/connection abort */
#define RXRPC_PACKET_TYPE_ACKALL    5   /* ACK all outstanding packets on call */
#define RXRPC_PACKET_TYPE_CHALLENGE 6   /* connection security challenge (SRVR->CLNT) */
#define RXRPC_PACKET_TYPE_RESPONSE  7   /* connection secutity response (CLNT->SRVR) */
#define RXRPC_PACKET_TYPE_DEBUG     8   /* debug info request */
#define RXRPC_N_PACKET_TYPES        9   /* number of packet types (incl type 0) */

    uint8_t     flags;      /* packet flags */
#define RXRPC_CLIENT_INITIATED  0x01        /* signifies a packet generated by a client */
#define RXRPC_REQUEST_ACK   0x02        /* request an unconditional ACK of this packet */
#define RXRPC_LAST_PACKET   0x04        /* the last packet from this side for this call */
#define RXRPC_MORE_PACKETS  0x08        /* more packets to come */
#define RXRPC_JUMBO_PACKET  0x20        /* [DATA] this is a jumbo packet */
#define RXRPC_SLOW_START_OK 0x20        /* [ACK] slow start supported */

    uint8_t     userStatus; /* app-layer defined status */
    uint8_t     securityIndex;  /* security protocol ID */
    union {
        __be16  _rsvd;      /* reserved */
        __be16  cksum;      /* kerberos security checksum */
    };
    __be16      serviceId;  /* service ID */

} __packed;

#define __rxrpc_header_off(X) offsetof(struct rxrpc_header,X)

extern const char *rxrpc_pkts[];

/*****************************************************************************/
/*
 * jumbo packet secondary header
 * - can be mapped to read header by:
 *   - new_serial = serial + 1
 *   - new_seq = seq + 1
 *   - new_flags = j_flags
 *   - new__rsvd = j__rsvd
 *   - duplicating all other fields
 */
struct rxrpc_jumbo_header {
    uint8_t     flags;      /* packet flags (as per rxrpc_header) */
    uint8_t     pad;
    __be16      _rsvd;      /* reserved (used by kerberos security as cksum) */
};

#define RXRPC_JUMBO_DATALEN 1412    /* non-terminal jumbo packet data length */

/*****************************************************************************/
/*
 * on-the-wire Rx ACK packet data payload
 * - all multibyte fields should be in network byte order
 */
struct rxrpc_ackpacket {
    __be16      bufferSpace;    /* number of packet buffers available */
    __be16      maxSkew;    /* diff between serno being ACK'd and highest serial no
                     * received */
    __be32      firstPacket;    /* sequence no of first ACK'd packet in attached list */
    __be32      previousPacket; /* sequence no of previous packet received */
    __be32      serial;     /* serial no of packet that prompted this ACK */

    uint8_t     reason;     /* reason for ACK */
#define RXRPC_ACK_REQUESTED     1   /* ACK was requested on packet */
#define RXRPC_ACK_DUPLICATE     2   /* duplicate packet received */
#define RXRPC_ACK_OUT_OF_SEQUENCE   3   /* out of sequence packet received */
#define RXRPC_ACK_EXCEEDS_WINDOW    4   /* packet received beyond end of ACK window */
#define RXRPC_ACK_NOSPACE       5   /* packet discarded due to lack of buffer space */
#define RXRPC_ACK_PING          6   /* keep alive ACK */
#define RXRPC_ACK_PING_RESPONSE     7   /* response to RXRPC_ACK_PING */
#define RXRPC_ACK_DELAY         8   /* nothing happened since received packet */
#define RXRPC_ACK_IDLE          9   /* ACK due to fully received ACK window */

    uint8_t     nAcks;      /* number of ACKs */
#define RXRPC_MAXACKS   255

    uint8_t     acks[0];    /* list of ACK/NAKs */
#define RXRPC_ACK_TYPE_NACK     0
#define RXRPC_ACK_TYPE_ACK      1

} __packed;

/*
 * ACK packets can have a further piece of information tagged on the end
 */
struct rxrpc_ackinfo {
    __be32      rxMTU;      /* maximum Rx MTU size (bytes) [AFS 3.3] */
    __be32      maxMTU;     /* maximum interface MTU size (bytes) [AFS 3.3] */
    __be32      rwind;      /* Rx window size (packets) [AFS 3.4] */
    __be32      jumbo_max;  /* max packets to stick into a jumbo packet [AFS 3.5] */
};

/*****************************************************************************/
/*
 * Kerberos security type-2 challenge packet
 */
struct rxkad_challenge {
    __be32      version;    /* version of this challenge type */
    __be32      nonce;      /* encrypted random number */
    __be32      min_level;  /* minimum security level */
    __be32      __padding;  /* padding to 8-byte boundary */
} __packed;

/*****************************************************************************/
/*
 * Kerberos security type-2 response packet
 */
struct rxkad_response {
    __be32      version;    /* version of this response type */
    __be32      __pad;

    /* encrypted bit of the response */
    struct {
        __be32      epoch;      /* current epoch */
        __be32      cid;        /* parent connection ID */
        __be32      checksum;   /* checksum */
        __be32      securityIndex;  /* security type */
        __be32      call_id[4]; /* encrypted call IDs */
        __be32      inc_nonce;  /* challenge nonce + 1 */
        __be32      level;      /* desired level */
    } encrypted;

    __be32      kvno;       /* Kerberos key version number */
    __be32      ticket_len; /* Kerberos ticket length  */
} __packed;

/*****************************************************************************/
/*
 * RxRPC-level abort codes
 */
#define RX_CALL_DEAD        -1  /* call/conn has been inactive and is shut down */
#define RX_INVALID_OPERATION    -2  /* invalid operation requested / attempted */
#define RX_CALL_TIMEOUT     -3  /* call timeout exceeded */
#define RX_EOF          -4  /* unexpected end of data on read op */
#define RX_PROTOCOL_ERROR   -5  /* low-level protocol error */
#define RX_USER_ABORT       -6  /* generic user abort */
#define RX_ADDRINUSE        -7  /* UDP port in use */
#define RX_DEBUGI_BADTYPE   -8  /* bad debugging packet type */

/*
 * (un)marshalling abort codes (rxgen)
 */
#define RXGEN_CC_MARSHAL    -450
#define RXGEN_CC_UNMARSHAL  -451
#define RXGEN_SS_MARSHAL    -452
#define RXGEN_SS_UNMARSHAL  -453
#define RXGEN_DECODE        -454
#define RXGEN_OPCODE        -455
#define RXGEN_SS_XDRFREE    -456
#define RXGEN_CC_XDRFREE    -457

/*
 * Rx kerberos security abort codes
 * - unfortunately we have no generalised security abort codes to say things
 *   like "unsupported security", so we have to use these instead and hope the
 *   other side understands
 */
#define RXKADINCONSISTENCY  19270400    /* security module structure inconsistent */
#define RXKADPACKETSHORT    19270401    /* packet too short for security challenge */
#define RXKADLEVELFAIL      19270402    /* security level negotiation failed */
#define RXKADTICKETLEN      19270403    /* ticket length too short or too long */
#define RXKADOUTOFSEQUENCE  19270404    /* packet had bad sequence number */
#define RXKADNOAUTH     19270405    /* caller not authorised */
#define RXKADBADKEY     19270406    /* illegal key: bad parity or weak */
#define RXKADBADTICKET      19270407    /* security object was passed a bad ticket */
#define RXKADUNKNOWNKEY     19270408    /* ticket contained unknown key version number */
#define RXKADEXPIRED        19270409    /* authentication expired */
#define RXKADSEALEDINCON    19270410    /* sealed data inconsistent */
#define RXKADDATALEN        19270411    /* user data too long */
#define RXKADILLEGALLEVEL   19270412    /* caller not authorised to use encrypted conns */

#endif /* _LINUX_RXRPC_PACKET_H */