C语言socket编程----struct sockaddr 和struct sockaddr_in介绍和初始化
sockaddr结构体
struct sockaddr{
sa_family_t sa_family; //地址族,最常用的是"AF_INET"(IPV4)和"AF_INET6"(IPV6);
char sa_data[14]; //包含套接字中的目标地址和端口信息;
};
sockaddr的缺陷:sa_data把目标地址和端口信息混在一起了
sockaddr_in 结构体
sockaddr_in结构体解决了sockaddr的缺陷,把port和addr 分开储存在两个变量中
struct sockaddr_in/ struct sockaddr_in6结构体
struct sockaddr_in{
sa_family_t sin_family; //地址族,常用AF_INET
uint16_t sin_port; //16位TCP/UDP端口号
struct in_addr sin_addr; //32位IP地址
cha sin_zero[8] //不使用
};
struct in_addr{
in_addr_t s_addr; //32位IPV4地址
}
struct sockaddr_in6 {
sa_family_t sin6_family; /* AF_INET6 */
in_port_t sin6_port; /* port number */
uint32_t sin6_flowinfo; /* IPv6 flow information */
struct in6_addr sin6_addr; /* IPv6 address */
uint32_t sin6_scope_id; /* Scope ID (new in 2.4) */
};
struct in6_addr {
unsigned char s6_addr[16]; /* IPv6 address */
};
struct sockaddr_in6相关详见 :http://man7.org/linux/man-pages/man7/ipv6.7.html
初始化和赋值:
IPV4
struct sockaddr_in ina;
bzero(&ina,sizeof(ina));
ina.sin_family=AF_INET;
ina.sin_port=htons(23);
ina.sin_addr.s_addr = inet_addr("132.241.5.10");
IPV4相关例子参考 http://www.cnblogs.com/huqian23456/archive/2011/02/22/1961822.html
IPV6
const ipv6_addr = "::1"; //IPV6地址
struct sockaddr saddr;
memset(&saddr, 0, sizeof(saddr)); / /初始化结构体
saddr.sa_family = AF_INET6;
inet_pton(AF_INET6,ipv6_addr,saddr.sa_data); //设置地址
struct sockaddr_in6 from_addr;
bzero(&from_addr,sizeof(from_addr)); //初始化结构体
from_addr.sin6_family = AF_INET6; //设置地址家族
from_addr.sin6_port = htons(800); //设置端口
inet_pton(AF_INET6,ipv6_addr,from_addr.sin6_addr.s6_addr ); //设置地址
inet_pton inet_ntop 地址转换相关详见 https://www.cnblogs.com/s7vens/archive/2011/12/12/2284964.html