我正在制作一个应用程序来测试 TCP 连接并研究网络协议(protocol)。同一应用程序是客户端还是服务器，具体取决于用户参数。 我正在使用 Dev-Cpp 5.11 在 Windows 10 上开发它。
但是，当我尝试像服务器一样运行它时，出现以下错误:
当它调用accept()时:
accept()返回SOCK_ERROR。WSAGetLastError()返回错误地址(直到listen()返回NULL)- 应用程序立即返回，没有客户端连接请求或延迟等待连接请求。
输出为:
:: SERVER MODE
:: PORT: 2020
:: Time Limit receiving: 1000ms
:: WSA Version: 0202
:: Criando SOCKET: OK
:: SOCKET Binding: OK
:: LISTENING . . .
WSA Error: Bad address
Socket Value: -1
ERRO 0 [Bad address]
--------------------------------
Process exited after 0.1634 seconds with return value 0
Pressione qualquer tecla para continuar. . .
这是使用参数调用的代码: csock-听2020
#include <stdio.h>
#include <time.h>
#include <stdlib.h>
#include <winsock2.h>
void delay(int milisecond);
char* LastErrorDescription();
/*****************************************************************************************
EXEMPLO DE PARAMETRO:
csock -h IP_v_4_Address -p Remote_Port -t 500
csock -listen 2020
******************************************************************************************/
/**************************************************
PENDENCIAS:
- IMPLEMENTAR IPv6
- IMPLEMENTAR MODO SERVIDOR
- REFAZER PARAMETROS PACKAGE (-pack)
***************************************************/
int main(int argc, char *argv[]) {
struct sockaddr_in sckAddr, adrIncomming;
char request[512] = ""; //= "GET http://www.brasil.gov.br HTTP/1.1\r\n\r\n"; //"GET /index.html HTTP/1.1\nHost: www.brasil.gov.br\n";
char BufferIn[10240];
WSADATA wsaDADOS;
int retWSA;
int retCon;
int retSend;
int retRecv;
int retBind;
int i;
int imsg;
int time_limit = 1000; // milisegundos aguardando recebimento de pacotes
clock_t registrador_tempo;
_Bool closed_connection = 0;
_Bool serverMode = 0;
_Bool nonpersist = 0;
_Bool bIPv6 = 0;
SOCKET wsocket;
SOCKET wserver;
WORD sckVersion = (2) << 8 | (2); // sckVersion 2.2 -> 0000001000000010
//printf("Quantidade de Parametros: %i", argc);
for(i = 0; i < argc; i ++){
if(!strcmp(argv[i], "-h")){
printf("\n:: HOST: %s", argv[i + 1]);
sckAddr.sin_addr.s_addr = inet_addr(argv[i + 1]);
}
if(!strcmp(argv[i], "-p")){
printf("\n:: PORT: %s", argv[i + 1]);
sckAddr.sin_port = htons(atoi(argv[i + 1]));
}
if(!strcmp(argv[i], "-t")){
time_limit = atoi(argv[i + 1]);
}
//COMANDOS MODO SERVIDOR
else if(!strcmp(argv[i], "-listen")){
serverMode = 1;
printf("\n:: SERVER MODE");
sckAddr.sin_addr.s_addr = htonl(INADDR_ANY);
sckAddr.sin_port = htons(atoi(argv[i + 1]));
printf("\n:: PORT: %s", argv[i + 1]);
}
}
printf("\n:: Time Limit receiving: %ims", time_limit);
// TRABALHO COM ENDEREÇO
sckAddr.sin_family = AF_INET; //23 == AF_INET6 para usar IPv6
//sckAddr.sin_port = htons(80);
//sckAddr.sin_addr.s_addr = inet_addr("170.246.252.243");
//Inicialização WSA Socket Application
printf("\n\n:: WSA Version: ");
retWSA = WSAStartup(sckVersion, &wsaDADOS);
if (retWSA == 0) {
printf("%04X", wsaDADOS.wVersion);
//Cria o SOCKET
printf("\n:: Criando SOCKET: ");
if(serverMode){
wserver = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if(wserver > 0){
printf("OK");
retBind = bind(wserver, (struct sockaddr*)&sckAddr, sizeof(sckAddr));
printf("\n:: SOCKET Binding: ");
if (retBind == 0)
printf("OK");
else
printf("ERRO %i [%s]", WSAGetLastError(), LastErrorDescription());
}
else
printf("ERRO %i [%s]", WSAGetLastError(), LastErrorDescription());
}
else { //CLIENT MODE
wsocket = socket(bIPv6 ? 23 : AF_INET, SOCK_STREAM, IPPROTO_TCP);
if(wsocket > 0)
printf("OK");
else
printf("ERRO %i [%s]", WSAGetLastError(), LastErrorDescription());
}
//MODO SERVIDOR
if(serverMode){
printf("\n\n:: LISTENING . . .\n");
listen(wserver, 2);
//do {
wsocket = accept(wserver, (struct sockaddr*)&adrIncomming, (int*)sizeof(adrIncomming));
printf("WSA Error: %s\nSocket Value: %i\n\n", LastErrorDescription(), wsocket); //TO DEPURATE
//} while(wsocket == SOCKET_ERROR);
closesocket(wserver);
if(wsocket != SOCKET_ERROR){
printf("\n:: Conexao estabelecida com: %s", inet_ntoa(adrIncomming.sin_addr)); //Tentar obter ENDEREÇO REMOTO com getpeername
retCon = 0;
}
else
retCon = -1;
}
//MODO CLIENTE
else{
//Conecta
printf("\n:: Conectando: ");
retCon = connect(wsocket, (struct sockaddr *)&sckAddr, sizeof(sckAddr));
if(retCon == 0)
printf("OK");
else
printf("ERRO %i [%s]", WSAGetLastError(), LastErrorDescription());
}
//CONEXAO ESTABELECIDA
if (retCon == 0) {
// ENVIA E RECEBE
while(strcmp(&request[0], "exIt")){
//ENVIA PACOTE
if (!nonpersist){
printf("\n\n:: ENVIAR>");
for(i=0;i<sizeof(request);i++)
request[i] = '\0';
fgets(&request, sizeof(request), stdin);
// Trata os PACOTES a serem ENVIADOS
for (i = 0; i < sizeof(request); i++){
if(request[i] == '\0'){
// Finaliza STRING 1 posicao antes ELIMINANDO Lf do fgets()
for(imsg = i - 1; imsg < sizeof(request); imsg++)
request[imsg] = '\0';
break;
}
// \n
else if (request[i] == '\\' && request[i + 1] == 'n'){
request[i] = '\n';
// Traz todos os caracteres para 1 posicao antes
for (imsg = i + 1; imsg < sizeof(request); imsg++)
request[imsg] = request[imsg + 1];
}
// \r
else if (request[i] == '\\' && request[i + 1] == 'r'){
request[i] = '\r';
// Traz todos os caracteres para 1 posicao antes
for (imsg = i + 1; imsg < sizeof(request); imsg++)
request[imsg] = request[imsg + 1];
}
}
}
//Depuracao: checar string de pacotes e ASCII da string de pacotes
/*
printf("\n\n%s.", &request);
printf("\n\n.");
for(i=0;i<sizeof(request);i++)
printf("%i ", request[i]);
printf(".");
*/
//Envia pacotes
if(strcmp(&request, "exIt")){
printf("\n:: Enviando pacotes: ");
if(send(wsocket, request, sizeof(request), 0) == SOCKET_ERROR){ // Erro no ENVIO
printf("ERRO %i [%s]", WSAGetLastError(), LastErrorDescription());
}
else //PACOTES ENVIADOS COM EXITO
printf("OK");
delay(time_limit);
//RECEBE PACOTE
retRecv = recv(wsocket, BufferIn, sizeof(BufferIn), 0);
if (retRecv == 0) {
printf("\n\n:: %s", LastErrorDescription());
break;
}
else {
printf("\n\n:: RECEBIDO:\n");
printf("%s", BufferIn);
}
}
//Finaliza se for conexao nao persistente
if(nonpersist)
strcpy(&request, "exIt");
}
}
else { //Erro na CONEXÃO
printf("ERRO %i [%s]", WSAGetLastError(), LastErrorDescription());
}
//Fecha o SOCKET
closesocket(wsocket);
}
else { // Erro no WSAStartup
printf("ERRO %i [%s]", WSAGetLastError(), LastErrorDescription());
}
// Finaliza Utilização do SOCKET
WSACleanup();
return 0;
}
void delay(int milisecond){
clock_t registra_tempo = clock();
while(clock() < registra_tempo + milisecond)
;
}
char* LastErrorDescription(){
static char* ret;
switch(WSAGetLastError()){
case WSAEINTR:{
ret = "Interrupted function call";
break;
}
case WSAEBADF:{
ret = "WSAEBADF";
break;
}
case WSAEACCES:{
ret = "WSAEACCES";
break;
}
case WSAEFAULT:{
ret = "Bad address";
break;
}
case WSAEINVAL:{
ret = "Invalid argument";
break;
}
case WSAEMFILE:{
ret = "Too many open files";
break;
}
case WSAEWOULDBLOCK:{
ret = "Operation would block";
break;
}
case WSAEINPROGRESS:{
ret = "Operation now in progress";
break;
}
case WSAEALREADY:{
ret = "Operation already in progress";
break;
}
case WSAENOTSOCK:{
ret = "Socket operation on non-socket";
break;
}
case WSAEDESTADDRREQ:{
ret = "Destination address required";
break;
}
case WSAEMSGSIZE:{
ret = "Message too long";
break;
}
case WSAEPROTOTYPE:{
ret = "Protocol wrong type for socket";
break;
}
case WSAENOPROTOOPT:{
ret = "Bad protocol option";
break;
}
case WSAEPROTONOSUPPORT:{
ret = "Protocol not supported";
break;
}
case WSAESOCKTNOSUPPORT:{
ret = "Socket type not supported";
break;
}
case WSAEOPNOTSUPP:{
ret = "Operation not supported";
break;
}
case WSAEPFNOSUPPORT:{
ret = "Protocol family not supported";
break;
}
case WSAEAFNOSUPPORT:{
ret = "Address family not supported by protocol family";
break;
}
case WSAEADDRINUSE:{
ret = "Address already in use";
break;
}
case WSAEADDRNOTAVAIL:{
ret = "Cannot assign requested address";
break;
}
case WSAENETDOWN:{
ret = "Network is down";
break;
}
case WSAENETUNREACH:{
ret = "Network is unreachable";
break;
}
case WSAENETRESET:{
ret = "Network dropped connection on reset";
break;
}
case WSAECONNABORTED:{
ret = "Software caused connection abort";
break;
}
case WSAECONNRESET:{
ret = "Connection reset by peer";
break;
}
case WSAENOBUFS:{
ret = "No buffer space available";
break;
}
case WSAEISCONN:{
ret = "Socket is already connected";
break;
}
case WSAENOTCONN:{
ret = "Socket is not connected";
break;
}
case WSAESHUTDOWN:{
ret = "Cannot send after socket shutdown";
break;
}
case WSAETOOMANYREFS:{
ret = "WSAETOOMANYREFS";
break;
}
case WSAETIMEDOUT:{
ret = "Connection timed out";
break;
}
case WSAECONNREFUSED:{
ret = "Connection refused";
break;
}
case WSAELOOP:{
ret = "WSAELOOP";
break;
}
case WSAENAMETOOLONG:{
ret = "WSAENAMETOOLONG";
break;
}
case WSAEHOSTDOWN:{
ret = "Host is down";
break;
}
case WSAEHOSTUNREACH:{
ret = "No route to host";
break;
}
case WSAENOTEMPTY:{
ret = "WSAENOTEMPTY";
break;
}
case WSAEPROCLIM:{
ret = "Too many processes";
break;
}
case WSAEUSERS:{
ret = "WSAEUSERS";
break;
}
case WSAEDQUOT:{
ret = "WSAEDQUOT";
break;
}
case WSAESTALE:{
ret = "WSAESTALE";
break;
}
case WSAEREMOTE:{
ret = "WSAEREMOTE";
break;
}
case WSASYSNOTREADY:{
ret = "Network subsystem is unavailable";
break;
}
case WSAVERNOTSUPPORTED:{
ret = "WINSOCK.DLL version out of range";
break;
}
case WSANOTINITIALISED:{
ret = "Successful WSAStartup() not yet performed";
break;
}
case WSAEDISCON:{
ret = "WSAEDISCON";
break;
}
case WSAENOMORE:{
ret = "WSAENOMORE";
break;
}
case WSAECANCELLED:{
ret = "WSAECANCELLED";
break;
}
case WSAEINVALIDPROCTABLE:{
ret = "WSAEINVALIDPROCTABLE";
break;
}
case WSAEINVALIDPROVIDER:{
ret = "WSAEINVALIDPROVIDER";
break;
}
case WSAEPROVIDERFAILEDINIT:{
ret = "WSAEPROVIDERFAILEDINIT";
break;
}
case WSASYSCALLFAILURE:{
ret = "WSASYSCALLFAILURE";
break;
}
case WSASERVICE_NOT_FOUND:{
ret = "WSASERVICE_NOT_FOUND";
break;
}
case WSATYPE_NOT_FOUND:{
ret = "WSATYPE_NOT_FOUND";
break;
}
case WSA_E_NO_MORE:{
ret = "WSA_E_NO_MORE";
break;
}
case WSA_E_CANCELLED:{
ret = "WSA_E_CANCELLED";
break;
}
case WSAEREFUSED:{
ret = "WSAEREFUSED";
break;
}
case WSAHOST_NOT_FOUND:{
ret = "Host not found";
break;
}
case WSATRY_AGAIN:{
ret = "Non-authoritative host not found";
break;
}
case WSANO_RECOVERY:{
ret = "This is a non-recoverable error";
break;
}
case WSANO_DATA:{
ret = "Valid name, no data record of requested type";
break;
}
}
return ret;
}
最佳答案
函数accept第三个参数addrlen是一个指针。它必须指向有效的内存位置。此外，它是一个输入/输出指针，即变量。因此，您必须创建一个变量，其值等于 adrIncomming 变量的大小。从 accept 返回后，变量将具有地址的实际长度。
这段代码比较合适。
int adrLength = sizeof(adrIncomming);
wsocket = accept(wserver, (struct sockaddr*)&adrIncomming, &adrLength);
编辑:此答案和示例中的链接特定于 WinSock API，因为该问题带有 Windows 标记。套接字 API 的其他实现可能具有不同的函数签名。
关于c - 没有连接请求时accept()返回SOCKET_ERROR，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/54194299/