我正在寻找一种方法来获取服务器的TCP端口号和IP地址，但是当前的方式输出了错误的IP地址，我得到的输出是0.0.33.32。希望能够得到帮助！
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <sys/wait.h>
#include <signal.h>
#include <time.h>
#define PORT "21467" // the port users will be connecting to
#define BACKLOG 10 // how many pending connections queue will hold
void sigchld_handler(int s)
{
while(waitpid(-1, NULL, WNOHANG) > 0);
}
// get sockaddr, IPv4 or IPv6:
void *get_in_addr(struct sockaddr *sa)
{
if (sa->sa_family == AF_INET) {
return &(((struct sockaddr_in*)sa)->sin_addr);
}
return &(((struct sockaddr_in6*)sa)->sin6_addr);
}
int main(void)
{
int sockfd, new_fd; // listen on sock_fd, new connection on new_fd
struct addrinfo hints, *servinfo, *p;
struct sockaddr_storage their_addr; // connector's address information
socklen_t sin_size;
struct sigaction sa;
int yes=1;
char s[INET6_ADDRSTRLEN];
int rv;
memset(&hints, 0, sizeof hints);
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
hints.ai_flags = AI_PASSIVE; // use my IP
char hname[100];
gethostname(hname, sizeof hname);
if ((rv = getaddrinfo(hname, PORT, &hints, &servinfo)) != 0) {
fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(rv));
return 1;
}
// loop through all the results and bind to the first we can
for(p = servinfo; p != NULL; p = p->ai_next) {
if ((sockfd = socket(p->ai_family, p->ai_socktype,
p->ai_protocol)) == -1) {
perror("server: socket");
continue;
}
if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &yes,
sizeof(int)) == -1) {
perror("setsockopt");
exit(1);
}
if (bind(sockfd, p->ai_addr, p->ai_addrlen) == -1) {
close(sockfd);
perror("server: bind");
continue;
}
break;
}
if (p == NULL) {
fprintf(stderr, "server: failed to bind\n");
return 2;
}
freeaddrinfo(servinfo); // all done with this structure
if (listen(sockfd, BACKLOG) == -1) {
perror("listen");
exit(1);
}
sa.sa_handler = sigchld_handler; // reap all dead processes
sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_RESTART;
if (sigaction(SIGCHLD, &sa, NULL) == -1) {
perror("sigaction");
exit(1);
}
char host[100];
char service[20];
getnameinfo(p->ai_addr, p->ai_addrlen, host, sizeof host, service, sizeof service, 0);
inet_ntop(p->ai_family, get_in_addr((struct sockaddr *)p->ai_addr),
host, sizeof host);
printf("server: has TCP port number %s and IP address %s\n", service, host);
printf("server: waiting for connections...\n");
int numbytes;
char buf[100];
while(1) { // main accept() loop
sin_size = sizeof their_addr;
new_fd = accept(sockfd, (struct sockaddr *)&their_addr, &sin_size);
if (new_fd == -1) {
perror("accept");
continue;
}
inet_ntop(their_addr.ss_family,
get_in_addr((struct sockaddr *)&their_addr),
s, sizeof s);
//getnameinfo(get_in_addr((struct sockaddr *)&their_addr), sizeof get_in_addr((struct sockaddr *)&their_addr), NULL, NULL, service, sizeof service, 0);
if ((numbytes = recv(new_fd, buf, 100, 0)) == -1)
perror("recv");
/* if ((numbytes = recv(sockfd, buf, 100, 0)) == -1) {
perror("recv");
exit(1);
}*/
struct tm* local;
char toClient[50];
printf("server: received '%s'\n",buf);
time_t curTime = time(0);
local = localtime(&curTime);
if(buf[0] == 't' ){
printf("server: received time request\n", s);
sprintf(toClient, "Time: %d::%d::%d", local->tm_hour, local->tm_min, local->tm_sec); //Seg faulting
printf("Sent the time to the client having IP address %s and port number %s\n", s, service);
}
else if(buf[0] == 'd'){
printf("server: received date request\n", s);
sprintf(toClient, "Date: %d::%d::%d", 1900+local->tm_year, 1+local->tm_mon, local->tm_mday);
printf("Sent the date to the client having IP address %s and port number %s\n", s, service);
}
else{
}
if ((numbytes = send(new_fd, toClient, sizeof toClient, 0)) == -1) {
perror("send");
exit(1);
}
close(new_fd);
break; //Temporary
}
close(sockfd);
return 0;
}
get_in_addr()的定义。这几乎肯定是一个网络字节顺序问题。 - trojanfoegetsockname来获取实际绑定的地址之外，为什么你还要同时使用getnameinfo和inet_ntop？使用getnameinfo就可以得到你想要的一切。 - Some programmer dude