但是当我使用相同的 Ipaddress 通过我的客户端代码连接到服务器时，它会给出连接接收 connect() failed: Connection refused。我希望通过getsockname（）检查服务器IP地址。我收到的IP地址是
地址是'0.0.0.0:9000' 我用这个我是一个使用Oracle Virtual box环境（Ubuntu）的大程序员请澄清我应该使用哪个IP地址传递给客户端以连接到服务器用法：./用法：./ <“ String"> 我基本上是在尝试制作一个 echo server 。提前致谢 。客户代码：#include "Practical.h"
int main(int argc, char *argv[]) {
if (argc < 3 || argc > 4) // Test for correct number of arguments
DieWithUserMessage("Parameter(s)",
"<Server Address> <Echo Word> [<Server Port>]");
char *servIP = argv[1]; // First arg: server IP address (dotted quad)
char *echoString = argv[2]; // Second arg: string to echo
// Third arg (optional): server port (numeric). 7 is well-known echo port
in_port_t servPort = (argc == 4) ? atoi(argv[3]) : 7;
// Create a reliable, stream socket using TCP
int sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (sock < 0)
DieWithSystemMessage("socket() failed");
// Construct the server address structure
struct sockaddr_in servAddr; // Server address
memset(&servAddr, 0, sizeof(servAddr)); // Zero out structure
servAddr.sin_family = AF_INET; // IPv4 address family
// Convert address
int rtnVal = inet_pton(AF_INET, servIP, &servAddr.sin_addr.s_addr);
if (rtnVal == 0)
DieWithUserMessage("inet_pton() failed", "invalid address string");
else if (rtnVal < 0)
DieWithSystemMessage("inet_pton() failed");
servAddr.sin_port = htons(servPort); // Server port
printf ("Hello");
// Establish the connection to the echo server
if (connect(sock, (struct sockaddr *) &servAddr, sizeof(servAddr)) < 0)
DieWithSystemMessage("connect() failed");
size_t echoStringLen = strlen(echoString); // Determine input length
// Send the string to the server
ssize_t numBytes = send(sock, echoString, echoStringLen, 0);
if (numBytes < 0)
DieWithSystemMessage("send() failed");
else if (numBytes != echoStringLen)
DieWithUserMessage("send()", "sent unexpected number of bytes");
// Receive the same string back from the server
unsigned int totalBytesRcvd = 0; // Count of total bytes received
fputs("Received: ", stdout); // Setup to print the echoed string
while (totalBytesRcvd < echoStringLen) {
char buffer[BUFSIZE]; // I/O buffer
/* Receive up to the buffer size (minus 1 to leave space for
a null terminator) bytes from the sender */
numBytes = recv(sock, buffer, BUFSIZE - 1, 0);
if (numBytes < 0)
DieWithSystemMessage("recv() failed");
else if (numBytes == 0)
DieWithUserMessage("recv()", "connection closed prematurely");
totalBytesRcvd += numBytes; // Keep tally of total bytes
buffer[numBytes] = '\0'; // Terminate the string!
fputs(buffer, stdout); // Print the echo buffer
}
fputc('\n', stdout); // Print a final linefeed
close(sock);
exit(0);
}
Server Code :
#define BUFSIZE 512
void HandleTCPClient(int clntSocket) {
char buffer[BUFSIZE]; // Buffer for echo string
// Receive message from client
ssize_t numBytesRcvd = recv(clntSocket, buffer, BUFSIZE, 0);
if (numBytesRcvd < 0)
printf("recv() failed");
// Send received string and receive again until end of stream
while (numBytesRcvd > 0) { // 0 indicates end of stream
// Echo message back to client
ssize_t numBytesSent = send(clntSocket, buffer, numBytesRcvd, 0);
if (numBytesSent < 0)
printf("send() failed");
else if (numBytesSent != numBytesRcvd)
printf("send()", "sent unexpected number of bytes");
// See if there is more data to receive
numBytesRcvd = recv(clntSocket, buffer, BUFSIZE, 0);
if (numBytesRcvd < 0)
printf("recv() failed");
}
close(clntSocket); // Close client socket
}
static const int MAXPENDING = 5;
int main(int argc, char *argv[]) {
if (argc != 2)
{
printf ("Parameters , <Server Port required >");
}
in_port_t servPort = atoi(argv[1]);
int servSock; // Socket descriptor for server
if ((servSock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0)
{
printf ( "Socket Failed ");
exit (1);
}
struct sockaddr_in servAddr; // Local address
memset(&servAddr, 0, sizeof(servAddr)); // Zero out structure
servAddr.sin_family = AF_INET; // IPv4 address family
servAddr.sin_addr.s_addr = htonl(INADDR_ANY); // Any incoming interface
servAddr.sin_port = htons(servPort); // Local port
// Bind to the local address
if (bind(servSock, (struct sockaddr*) &servAddr, sizeof(servAddr)) < 0)
{
printf ("Bind Failed ");
exit (1);
}
// Mark the socket so it will listen for incoming connections
if (listen(servSock, MAXPENDING) < 0)
printf("listen() failed");
for (;;) { // Run forever
struct sockaddr_in clntAddr; // Client address
// Set length of client address structure (in-out parameter)
socklen_t clntAddrLen = sizeof(clntAddr);
// Wait for a client to connect
int clntSock = accept(servSock, (struct sockaddr *) &clntAddr, &clntAddrLen);
if (clntSock < 0)
printf ("accept() failed");
// clntSock is connected to a client!
char clntName[INET_ADDRSTRLEN]; // String to contain client address
if (inet_ntop(AF_INET, &clntAddr.sin_addr.s_addr, clntName,
sizeof(clntName)) != NULL)
printf("Handling client %s/%d\n", clntName, ntohs(clntAddr.sin_port));
else
puts("Unable to get client address");
HandleTCPClient(clntSock);
}
// NOT REACHED
}
Code is not mine I have Copied for Practice