网络编程中4个重要的地址数据结构

ゞ浴缸里的玫瑰 2023-07-26 05:27 6阅读 0赞

IPv4: struct sockaddr\_in, 16个字节

struct sockaddr_in { 
           sa_family_t sin_family;             /* AF_INET */
           in_port_t sin_port;                 /* Port number. */
           struct in_addr sin_addr;            /* Internet address. */
      
           /* Pad to size of `struct sockaddr'. */
           unsigned char sin_zero[sizeof (struct sockaddr) -
                                  sizeof (sa_family_t) -
                                  sizeof (in_port_t) -
                                 sizeof (struct in_addr)];
    };
    typedef uint32_t in_addr_t;
    struct in_addr  { 
         in_addr_t s_addr;                    /* IPv4 address */
    };

IPv6: struct sockaddr\_in6, 28个字节

struct sockaddr_in6 { 
         sa_family_t sin6_family;    /* AF_INET6 */
         in_port_t sin6_port;        /* Transport layer port # */
         uint32_t sin6_flowinfo;     /* IPv6 flow information */
         struct in6_addr sin6_addr;  /* IPv6 address */
         uint32_t sin6_scope_id;     /* IPv6 scope-id */
     };
     struct in6_addr { 
         union { 
             uint8_t u6_addr8[16];
             uint16_t u6_addr16[8];
             uint32_t u6_addr32[4];
         } in6_u;
     
         #define s6_addr in6_u.u6_addr8
         #define s6_addr16 in6_u.u6_addr16
         #define s6_addr32 in6_u.u6_addr32
     };

通用结构体1: struct sockaddr, 16个字节

struct sockaddr {  
         sa_family_t sa_family;       /* Address family */
         char sa_data[14];            /* protocol-specific address */
    };

通用结构体2: struct sockaddr\_storage,128个字节

/* Structure large enough to hold any socket address (with the historical exception of AF_UNIX). 128 bytes reserved. */
      
      #if ULONG_MAX > 0xffffffff
      # define __ss_aligntype __uint64_t
      #else
      # define __ss_aligntype __uint32_t
      #endif
      #define _SS_SIZE 128
     #define _SS_PADSIZE (_SS_SIZE - (2 * sizeof (__ss_aligntype)))
     
     struct sockaddr_storage
     { 
         sa_family_t ss_family;      /* Address family */
         __ss_aligntype __ss_align;  /* Force desired alignment. */
         char __ss_padding[_SS_PADSIZE];
    };