字序转换。
htonl
htons
ntohl
ntohs
struck sockaddr
{
sa_family_t sa_family;
char sa_data[];
}
struck in_addr
{
in_addr_t s_addr;
}
struck sockaddr_in
{
sa_family_t sa_family;
in_port_t sin_port;
struct in_addr sin_addr;
}
二进制和点分转换。
inet_ntop inet_pton
#include <arpa/inet.h>
const char *inet_ntop(int domain, const void *restrict addr,char *restrict str, socklen_t size);
Returns: pointer to address string on success, NULL on error
int inet_pton(int domain, const char *restrict str,void *restrict addr);
Returns: 1 on success, 0 if the format is invalid, or −1 on error
地址查询。
struct hostent {
char *h_name; /* name of host */
char **h_aliases; /* pointer to alternate host name array */
int h_addrtype; /* address type */
int h_length; /* length in bytes of address */
char **h_addr_list; /* pointer to array of network addresses */
.
.
.
};
#include <netdb.h>
struct hostent *gethostent(void);
Returns: pointer if OK, NULL on error
void sethostent(int stayopen);
void endhostent(void);
早期函数：gethostbyname and gethostbyaddr
struct netent {
char *n_name; /* network name */
char **n_aliases; /* alternate network name array pointer */
int n_addrtype; /* address type */
uint32_t n_net; /* network number */
.
.
.
};
struct netent *getnetbyaddr(uint32_t net, int type);
struct netent *getnetbyname(const char *name);
struct netent *getnetent(void);
All return: pointer if OK, NULL on error
void setnetent(int stayopen);
void endnetent(void);
服务和名字之间的转换。
struct protoent {
char *p_name; /* protocol name */
char **p_aliases; /* pointer to alternate protocol name array */
int p_proto; /* protocol number */
.
.
.
};
#include <netdb.h>
struct protoent *getprotobyname(const char *name);
struct protoent *getprotobynumber(int proto);
struct protoent *getprotoent(void);
All return: pointer if OK, NULL on error
void setprotoent(int stayopen);
void endprotoent(void);
查询服务。
struct servent {
char *s_name; /* service name */
char **s_aliases; /* pointer to alternate service name array */
int s_port; /* port number */
char *s_proto; /* name of protocol */
.
.
.
};
#include <netdb.h>
struct servent *getservbyname(const char *name, const char *proto);
struct servent *getservbyport(int port, const char *proto);
struct servent *getservent(void);
All return: pointer if OK, NULL on error
void setservent(int stayopen);
void endservent(void);
//根据服务和主机名，返回一个节点数据结构是assrinfo的链表。
#include <sys/socket.h>
#include <netdb.h>
struct addrinfo {
int ai_flags; /* customize behavior */
int ai_family; /* address family */
int ai_socktype; /* socket type */
int ai_protocol; /* protocol */
socklen_t ai_addrlen; /* length in bytes of address */
struct sockaddr *ai_addr; /* address */
char *ai_canonname; /* canonical name of host */
struct addrinfo *ai_next; /* next in list */
.
.
.
};
int getaddrinfo(const char *restrict host,
const char *restrict service,
const struct addrinfo *restrict hint,
struct addrinfo **restrict res);
Returns: 0 if OK, nonzero error code on error
void freeaddrinfo(struct addrinfo *ai);
//将地址转换为主机名和服务名
#include <sys/socket.h>
#include <netdb.h>
int getnameinfo(const struct sockaddr *restrict addr, socklen_t alen,
char *restrict host, socklen_t hostlen,
char *restrict service, socklen_t servlen, int flags);
Returns: 0 if OK, nonzero on error
//通过socket得到address。
#include <sys/socket.h>
int getsockname(int sockfd, struct sockaddr *restrict addr,
socklen_t *restrict alenp);
Returns: 0 if OK, −1 on error
//如果已经连接。还可以通过socket得到对端address。
#include <sys/socket.h>
int getpeername(int sockfd, struct sockaddr *restrict addr,
socklen_t *restrict alenp);
Returns: 0 if OK, −1 on error
//连接。
#include <sys/socket.h>
int connect(int sockfd, const struct sockaddr *addr, socklen_t len);
Returns: 0 if OK, −1 on error
//监听。
//#include <sys/socket.h>
int listen(int sockfd, int backlog);
Returns: 0 if OK, −1 on error
//接受。
#include <sys/socket.h>
int accept(int sockfd, struct sockaddr *restrict addr,
socklen_t *restrict len);
Returns: file (socket) descriptor if OK, −1 on error
//数据传输。
#include <sys/socket.h>
ssize_t send(int sockfd, const void *buf, size_t nbytes, int flags);
Returns: number of bytes sent if OK, −1 on error
//数据传输。非可靠连接
#include <sys/socket.h>
ssize_t sendto(int sockfd, const void *buf, size_t nbytes, int flags,
const struct sockaddr *destaddr, socklen_t destlen);
Returns: number of bytes sent if OK, −1 on error
//更多选择。
#include <sys/socket.h>
ssize_t sendmsg(int sockfd, const struct msghdr *msg, int flags);
Returns: number of bytes sent if OK, −1 on error
//接受数据。
#include <sys/socket.h>
ssize_t recv(int sockfd, void *buf, size_t nbytes, int flags);
Returns: length of message in bytes,
0 if no messages are available and peer has done an orderly shutdown,
//更多选项。
#include <sys/socket.h>
ssize_t recvfrom(int sockfd, void *restrict buf, size_t len, int flags,
struct sockaddr *restrict addr,
socklen_t *restrict addrlen);
Returns: length of message in bytes,
0 if no messages are available and peer has done an orderly shutdown,
or −1 on error
or −1 on error
//
#include <sys/socket.h>
ssize_t recvmsg(int sockfd, struct msghdr *msg, int flags);
Returns: length of message in bytes,
0 if no messages are available and peer has done an orderly shutdown,
//socket option
#include <sys/socket.h>
int setsockopt(int sockfd, int level, int option, const void *val,
socklen_t len);
Returns: 0 if OK, −1 on error
//带外数据。
#include <sys/socket.h>
int sockatmark(int sockfd);
Returns: 1 if at mark, 0 if not at mark, −1 on error
//非阻塞和异步。