if_packet.h

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#ifndef __LINUX_IF_PACKET_H
#define __LINUX_IF_PACKET_H

#include <linux/types.h>

struct sockaddr_pkt {
    unsigned short spkt_family;
    unsigned char spkt_device[14];
    __be16 spkt_protocol;
};

struct sockaddr_ll {
    unsigned short  sll_family;
    __be16      sll_protocol;
    int     sll_ifindex;
    unsigned short  sll_hatype;
    unsigned char   sll_pkttype;
    unsigned char   sll_halen;
    unsigned char   sll_addr[8];
};

/* Packet types */

#define PACKET_HOST     0       /* To us        */
#define PACKET_BROADCAST    1       /* To all       */
#define PACKET_MULTICAST    2       /* To group     */
#define PACKET_OTHERHOST    3       /* To someone else  */
#define PACKET_OUTGOING     4       /* Outgoing of any type */
/* These ones are invisible by user level */
#define PACKET_LOOPBACK     5       /* MC/BRD frame looped back */
#define PACKET_FASTROUTE    6       /* Fastrouted frame */

/* Packet socket options */

#define PACKET_ADD_MEMBERSHIP       1
#define PACKET_DROP_MEMBERSHIP      2
#define PACKET_RECV_OUTPUT      3
/* Value 4 is still used by obsolete turbo-packet. */
#define PACKET_RX_RING          5
#define PACKET_STATISTICS       6
#define PACKET_COPY_THRESH      7
#define PACKET_AUXDATA          8
#define PACKET_ORIGDEV          9
#define PACKET_VERSION          10
#define PACKET_HDRLEN           11
#define PACKET_RESERVE          12
#define PACKET_TX_RING          13
#define PACKET_LOSS         14
#define PACKET_VNET_HDR         15
#define PACKET_TX_TIMESTAMP     16
#define PACKET_TIMESTAMP        17
#define PACKET_FANOUT           18

#define PACKET_FANOUT_HASH      0
#define PACKET_FANOUT_LB        1
#define PACKET_FANOUT_CPU       2
#define PACKET_FANOUT_FLAG_DEFRAG   0x8000

struct tpacket_stats {
    unsigned int    tp_packets;
    unsigned int    tp_drops;
};

struct tpacket_stats_v3 {
    unsigned int    tp_packets;
    unsigned int    tp_drops;
    unsigned int    tp_freeze_q_cnt;
};

union tpacket_stats_u {
    struct tpacket_stats stats1;
    struct tpacket_stats_v3 stats3;
};

struct tpacket_auxdata {
    __u32       tp_status;
    __u32       tp_len;
    __u32       tp_snaplen;
    __u16       tp_mac;
    __u16       tp_net;
    __u16       tp_vlan_tci;
    __u16       tp_padding;
};

/* Rx ring - header status */
#define TP_STATUS_KERNEL    0x0
#define TP_STATUS_USER      0x1
#define TP_STATUS_COPY      0x2
#define TP_STATUS_LOSING    0x4
#define TP_STATUS_CSUMNOTREADY  0x8
#define TP_STATUS_VLAN_VALID   0x10 /* auxdata has valid tp_vlan_tci */
#define TP_STATUS_BLK_TMO   0x20

/* Tx ring - header status */
#define TP_STATUS_AVAILABLE 0x0
#define TP_STATUS_SEND_REQUEST  0x1
#define TP_STATUS_SENDING   0x2
#define TP_STATUS_WRONG_FORMAT  0x4

/* Rx ring - feature request bits */
#define TP_FT_REQ_FILL_RXHASH   0x1

struct tpacket_hdr {
    unsigned long   tp_status;
    unsigned int    tp_len;
    unsigned int    tp_snaplen;
    unsigned short  tp_mac;
    unsigned short  tp_net;
    unsigned int    tp_sec;
    unsigned int    tp_usec;
};

#define TPACKET_ALIGNMENT   16
#define TPACKET_ALIGN(x)    (((x)+TPACKET_ALIGNMENT-1)&~(TPACKET_ALIGNMENT-1))
#define TPACKET_HDRLEN      (TPACKET_ALIGN(sizeof(struct tpacket_hdr)) + sizeof(struct sockaddr_ll))

struct tpacket2_hdr {
    __u32       tp_status;
    __u32       tp_len;
    __u32       tp_snaplen;
    __u16       tp_mac;
    __u16       tp_net;
    __u32       tp_sec;
    __u32       tp_nsec;
    __u16       tp_vlan_tci;
    __u16       tp_padding;
};

struct tpacket_hdr_variant1 {
    __u32   tp_rxhash;
    __u32   tp_vlan_tci;
};

struct tpacket3_hdr {
    __u32       tp_next_offset;
    __u32       tp_sec;
    __u32       tp_nsec;
    __u32       tp_snaplen;
    __u32       tp_len;
    __u32       tp_status;
    __u16       tp_mac;
    __u16       tp_net;
    /* pkt_hdr variants */
    union {
        struct tpacket_hdr_variant1 hv1;
    };
};

struct tpacket_bd_ts {
    unsigned int ts_sec;
    union {
        unsigned int ts_usec;
        unsigned int ts_nsec;
    };
};

struct tpacket_hdr_v1 {
    __u32   block_status;
    __u32   num_pkts;
    __u32   offset_to_first_pkt;

    /* Number of valid bytes (including padding)
     * blk_len <= tp_block_size
     */
    __u32   blk_len;

    /*
     * Quite a few uses of sequence number:
     * 1. Make sure cache flush etc worked.
     *    Well, one can argue - why not use the increasing ts below?
     *    But look at 2. below first.
     * 2. When you pass around blocks to other user space decoders,
     *    you can see which blk[s] is[are] outstanding etc.
     * 3. Validate kernel code.
     */
    __aligned_u64   seq_num;

    /*
     * ts_last_pkt:
     *
     * Case 1.  Block has 'N'(N >=1) packets and TMO'd(timed out)
     *      ts_last_pkt == 'time-stamp of last packet' and NOT the
     *      time when the timer fired and the block was closed.
     *      By providing the ts of the last packet we can absolutely
     *      guarantee that time-stamp wise, the first packet in the
     *      next block will never precede the last packet of the
     *      previous block.
     * Case 2.  Block has zero packets and TMO'd
     *      ts_last_pkt = time when the timer fired and the block
     *      was closed.
     * Case 3.  Block has 'N' packets and NO TMO.
     *      ts_last_pkt = time-stamp of the last pkt in the block.
     *
     * ts_first_pkt:
     *      Is always the time-stamp when the block was opened.
     *      Case a) ZERO packets
     *          No packets to deal with but atleast you know the
     *          time-interval of this block.
     *      Case b) Non-zero packets
     *          Use the ts of the first packet in the block.
     *
     */
    struct tpacket_bd_ts    ts_first_pkt, ts_last_pkt;
};

union tpacket_bd_header_u {
    struct tpacket_hdr_v1 bh1;
};

struct tpacket_block_desc {
    __u32 version;
    __u32 offset_to_priv;
    union tpacket_bd_header_u hdr;
};

#define TPACKET2_HDRLEN     (TPACKET_ALIGN(sizeof(struct tpacket2_hdr)) + sizeof(struct sockaddr_ll))
#define TPACKET3_HDRLEN     (TPACKET_ALIGN(sizeof(struct tpacket3_hdr)) + sizeof(struct sockaddr_ll))

enum tpacket_versions {
    TPACKET_V1,
    TPACKET_V2,
    TPACKET_V3
};

/*
   Frame structure:

   - Start. Frame must be aligned to TPACKET_ALIGNMENT=16
   - struct tpacket_hdr
   - pad to TPACKET_ALIGNMENT=16
   - struct sockaddr_ll
   - Gap, chosen so that packet data (Start+tp_net) alignes to TPACKET_ALIGNMENT=16
   - Start+tp_mac: [ Optional MAC header ]
   - Start+tp_net: Packet data, aligned to TPACKET_ALIGNMENT=16.
   - Pad to align to TPACKET_ALIGNMENT=16
 */

struct tpacket_req {
    unsigned int    tp_block_size;  /* Minimal size of contiguous block */
    unsigned int    tp_block_nr;    /* Number of blocks */
    unsigned int    tp_frame_size;  /* Size of frame */
    unsigned int    tp_frame_nr;    /* Total number of frames */
};

struct tpacket_req3 {
    unsigned int    tp_block_size;  /* Minimal size of contiguous block */
    unsigned int    tp_block_nr;    /* Number of blocks */
    unsigned int    tp_frame_size;  /* Size of frame */
    unsigned int    tp_frame_nr;    /* Total number of frames */
    unsigned int    tp_retire_blk_tov; /* timeout in msecs */
    unsigned int    tp_sizeof_priv; /* offset to private data area */
    unsigned int    tp_feature_req_word;
};

union tpacket_req_u {
    struct tpacket_req  req;
    struct tpacket_req3 req3;
};

struct packet_mreq {
    int     mr_ifindex;
    unsigned short  mr_type;
    unsigned short  mr_alen;
    unsigned char   mr_address[8];
};

#define PACKET_MR_MULTICAST 0
#define PACKET_MR_PROMISC   1
#define PACKET_MR_ALLMULTI  2
#define PACKET_MR_UNICAST   3

#endif