libnet

libnet的結構眾多，幾乎都是封包表頭，這裡無法一一列出（因為很佔空間），只會把主要需要的列出。

地址相關

/*
 * IPv6 address
 */
struct libnet_in6_addr
{
    union
    {
        uint8_t   __u6_addr8[16];
        uint16_t  __u6_addr16[8];
        uint32_t  __u6_addr32[4];
    } __u6_addr;            /* 128-bit IP6 address */
};
#define libnet_s6_addr __u6_addr.__u6_addr8

• 說明：IPv6網路順序地址結構。
• 成員：
  • __u6_addr：一個聯合體（union），基本上就是一個128 bits長度的欄位資料。

libnet核心相關

/*
 *  Libnet context
 *  Opaque structure.  Nothing in here should ever been touched first hand by
 *  the applications programmer.
 */
struct libnet_context
{
#if ((__WIN32__) && !(__CYGWIN__)) 
    SOCKET fd;
    LPADAPTER  lpAdapter;
#else
    int fd;                             /* file descriptor of packet device */
#endif
    int injection_type;                 /* one of: */
#define LIBNET_NONE     0xf8            /* no injection type, only construct packets */
#define LIBNET_LINK     0x00            /* link-layer interface */
#define LIBNET_RAW4     0x01            /* raw socket interface (ipv4) */
#define LIBNET_RAW6     0x02            /* raw socket interface (ipv6) */
/* the following should actually set a flag in the flags variable above */
#define LIBNET_LINK_ADV 0x08            /* advanced mode link-layer */
#define LIBNET_RAW4_ADV 0x09            /* advanced mode raw socket (ipv4) */
#define LIBNET_RAW6_ADV 0x0a            /* advanced mode raw socket (ipv6) */
#define LIBNET_ADV_MASK 0x08            /* mask to determine adv mode */

    /* _blocks is the highest level, and _end is closest to link-level */
    libnet_pblock_t *protocol_blocks;   /* protocol headers / data */
    libnet_pblock_t *pblock_end;        /* last node in list */
    uint32_t n_pblocks;                /* number of pblocks */

    int link_type;                      /* link-layer type, a DLT_ value. */
    /* These are the only values used by libnet (see libnet_build_arp and
     * libnet_build_link).  Other values are assigned by the various
     * libnet_link_*.c OS support functions, but are not yet used or supported,
     * they are effectively dead code. <pcap.h> claims these two are invariant
     * across operating systems... hopefully it is correct!
     */
#ifndef DLT_EN10MB
# define DLT_EN10MB      1       /* Ethernet (10Mb) */
#endif
#ifndef DLT_IEEE802
# define DLT_IEEE802     6       /* IEEE 802 Networks */
#endif

    int link_offset;                    /* link-layer header size */
    int aligner;                        /* used to align packets */
    char *device;                       /* device name */

    struct libnet_stats stats;          /* statistics */
    libnet_ptag_t ptag_state;           /* state holder for pblock tag */
    char label[LIBNET_LABEL_SIZE];      /* textual label for cq interface */

    char err_buf[LIBNET_ERRBUF_SIZE];   /* error buffer */
    uint32_t total_size;               /* total size */
};
typedef struct libnet_context libnet_t;

• 說明：這個結構體就是libnet_t，我們不能直接使用結構體內的成員，必須透過libnet提供的其他函數操作。

/*
 *  Libnet context queue structure
 *  Opaque structure.  Nothing in here should ever been touched first hand by
 *  the applications programmer.
 */
typedef struct _libnet_context_queue libnet_cq_t;
struct _libnet_context_queue
{
    libnet_t *context;                  /* pointer to libnet context */
    libnet_cq_t *next;                  /* next node in the list */
    libnet_cq_t *prev;                  /* previous node in the list */
};

struct _libnet_context_queue_descriptor
{
    uint32_t node;                     /* number of nodes in the list */
    uint32_t cq_lock;                  /* lock status */
    libnet_cq_t *current;               /* current context */
};
typedef struct _libnet_context_queue_descriptor libnet_cqd_t;

• 說明：這個結構體就是libnet handle鏈結串列，必須透過libnet提供的其他函數操作。

/* port list chain structure */
typedef struct libnet_port_list_chain libnet_plist_t;
struct libnet_port_list_chain
{
    uint16_t node;                     /* node number */
    uint16_t bport;                    /* beggining port */
    uint16_t eport;                    /* terminating port */
    uint8_t  id;                       /* global array offset */
    libnet_plist_t *next;               /* next node in the list */
};

• 說明：這個結構體就是libnet_plist_t，我們不能直接使用結構體內的成員，必須透過libnet提供的其他函數操作。

/* libnet statistics structure */
struct libnet_stats
{
#if (!defined(__WIN32__) || (__CYGWIN__))
    uint64_t packets_sent;             /* packets sent */
    uint64_t packet_errors;            /* packets errors */
    uint64_t bytes_written;            /* bytes written */
#else
    __int64 packets_sent;               /* packets sent */
    __int64 packet_errors;              /* packets errors */
    __int64 bytes_written;              /* bytes written */
#endif
};

• 說明：libnet handle送出封包狀態結構，需要搭配函數libnet_stats()使用。
• 成員：
  • packets_sent：封包總共送出幾個。
  • packet_errors：幾個封包再送出時發生錯誤。
  • bytes_written：封包總共送出多少bytes。