Привет, я программирую сетевой клиент на языке c и использую функцию getsocketname, чтобы вернуть IP и порт сокета, который я создал, но по какой-то причине IP всегда возвращается как 0.0.0.0, вот код:
#include <stdio.h> //include standard input/output library
#include <stdlib.h> //include standard libraries
#include <string.h> //include string headers
#include <unistd.h> //add definitions for constansts and functions
#include <sys/types.h> // include definitions for different data types
#include <sys/socket.h> //include socket support
#include <netinet/in.h> //define internet protocol functions
#include <arpa/inet.h> //define internet protocol functions
#include "Practical.h" //include practical header file
int main(int argc, char *argv[]) {
char myIP[16];
unsigned int myPort;
struct sockaddr_in server_addr,myaddr;
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; //21
// Create a reliable, stream socket using TCP //23
int sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);//this block of code creates a reliable tcp stream socket and checks what the returned integer is from the socket function, the returned function will give a integer that descibes the socket. if this is 0 then kill the socket and show the user an error message.
if (sock < 0)
DieWithSystemMessage("socket() failed"); //26
// Construct the server address structure //28
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
myaddr.sin_addr.s_addr = INADDR_LOOPBACK;
bzero(&myaddr,sizeof(myaddr));
int len = sizeof(myaddr);
getsockname(sock,(struct sockaddr *) &myaddr, &len);
inet_ntop(AF_INET, &myaddr.sin_addr, myIP, sizeof(myIP));
myPort = ntohs(myaddr.sin_port);
printf("local ip address : %s\n", myIP);
printf("local port: %u\n", myPort);
// 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 //44
// Send the string to the server
ssize_t numBytes = send(sock, echoString, echoStringLen, 0);
if (numBytes < 0) //sending string to server, number of bytes of the message is equal to return value of send function, if the number of bytes is less than 0 then do not send and say to user that the send failed
DieWithSystemMessage("send() failed");
else if (numBytes != echoStringLen)
DieWithUserMessage("send()", "sent unexpected number of bytes"); //51
// if the number of bytes is not equal to the input length of the string parsed as an argument then die with the message to the user saying sent unexpected number of bytes.
// Receive the same string back from the server //53
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 //70
close(sock);
exit(0);
}
//closing off connections to clean up data left over.
номер возвращаемого порта также всегда равен 0, я назначаю адрес структуры myaddr в качестве петлевого адреса, поэтому я считаю, что он должен возвращать 127.0.0.1 в качестве IP-адреса, но это не так,Я новичок в программировании сокетов, поэтому моя логика может быть не идеальной, я просто не вижу, что здесь не так