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我在C++中有一個套接字服務器，我正在使用epoll。我正在向服務器發送一個包含HeaderPacket和NormalPacket的字符。 首先我正在閱讀HeaderPacket，然後閱讀NormalPacket。我現在的問題是，當我關閉客戶端（我試圖使用關閉和關閉 - 相同的輸出）時，我在第一個recv（讀取頭數據包的那個）上得到了一些奇怪的字節，並且在分段錯誤。另外，當我將我的內容字符的大小從HeaderPacket更改爲另一個值（例如120）時，我沒有得到分段錯誤，但是當我將它設置爲40或其他值時，我得到了分段錯誤。帶epoll的套接字服務器在斷開時給出未知字節
#define BUFFERSIZE 256
#define CHARSIZE 40
這裏是我用它來閱讀功能：
void PacketHandler::ReadBytes(int fd, struct HeaderPacket &hp, char buffer[])
{
int reading = 0;
ssize_t hpCount, cpCount;
char hpBuffer[6];
hpCount = recv(fd, hpBuffer, 6, 0);
if(hpCount <= 0)
{
reading = 1;
} else {
this->UnserializeHeaderPacket(hpBuffer, hp);
print(DEBUG, Helpers::IntegerToString(hp.length));
cpCount = hp.length;
char cpBuffer[cpCount];
memset(cpBuffer, 0, sizeof(cpBuffer));
char* iterator = cpBuffer;
int bytesLeft = sizeof(cpBuffer) - sizeof(char);
print(DEBUG, Helpers::IntegerToString(bytesLeft));
if(bytesLeft < 0)
{
reading = 1;
}
while(bytesLeft > 0)
{
ssize_t curr;
curr = recv(fd, iterator, bytesLeft, 0);
if(curr == -1)
{
if(errno != EAGAIN)
{
reading = 1;
print(WARNING, "reading error at content packet");
}
break;
} else if(curr == 0) {
reading = 1;
break;
}
iterator += curr;
bytesLeft -= curr;
}
memcpy(buffer, cpBuffer, sizeof cpBuffer);
}
if(reading)
{
print(NOTICE, "Closed connection with the descriptor " + Helpers::IntegerToString(fd));
close(fd);
}
}
這裏是epoll的功能
void EventHandler::RunningLoop(int fd)
{
while(1)
{
int availableEvents, i;
availableEvents = epoll_wait(this->efd, this->events, MAXEVENTS, -1);
for(i = 0; i < availableEvents; i++)
{
if(this->events[i].data.fd == fd)
{
// Accepting new connection
this->AcceptClient(fd);
continue;
}
else if((this->events[i].events & EPOLLERR) || (this->events[i].events & EPOLLHUP) || (!(this->events[i].events & EPOLLIN)))
{
print(WARNING, "epoll error on reading from fd");
close (this->events[i].data.fd);
continue;
}
else if(this->events[i].events & EPOLLRDHUP)
{
print(WARNING, "intern close socket");
close (this->events[i].data.fd);
} else {
// Reading packets
this->run->InitializePacket(this->events[i].data.fd); // cals the read function
}
}
}
free(this->events);
close(fd);
}
我的包：
struct HeaderPacket
{
uint16_t opcode;
uint32_t length;
};
struct HelloWorldPacket
{
uint16_t byteOrder;
char content[CHARSIZE];
};
功能序列化：
void PacketHandler::SerializeHeaderPacket(HeaderPacket packet, char buffer[])
{
uint16_t u16;
uint32_t u32;
u16 = htons(packet.opcode);
memcpy(buffer+0, &u16, 2);
u32 = htonl(packet.length);
memcpy(buffer+2, &u32, 4);
}
void PacketHandler::UnserializeHeaderPacket(char buffer[], HeaderPacket &packet)
{
uint16_t u16;
uint32_t u32;
memcpy(&u16, buffer+0, 2);
packet.opcode = ntohs(u16);
memcpy(&u32, buffer+2, 4);
packet.length = ntohl(u32);
}
void PacketHandler::SerializeHelloWorldPacket(HelloWorldPacket packet, char buffer[])
{
uint16_t u16;
u16 = htons(packet.byteOrder);
memcpy(buffer+0, &u16, 2);
memcpy(buffer+2, &packet.content, sizeof packet.content);
}
void PacketHandler::UnserializeHelloWorldPacket(char buffer[], HelloWorldPacket &packet)
{
uint16_t u16;
memcpy(&u16, buffer+0, 2);
packet.byteOrder = ntohs(u16);
strcpy(packet.content, buffer+2);
}
這就是我如何將數據發送到服務器：
int EventHandler::SendHelloWorld(int fd)
{
HeaderPacket hp;
HelloWorldPacket hc;
char buffer[256];
int sendResult;
char message[] = "hello_first_message\r\n";
hp.opcode = HELLOWORLD;
hp.length = sizeof message;
memcpy(hc.content, message, sizeof message);
packets->SerializeHeaderPacket(hp, buffer);
packets->SerializeHelloWorldPacket(hc, buffer+6);
sendResult = write(fd, buffer, sizeof buffer);
return sendResult;
}
感謝您的幫助。
它編譯沒有錯誤和警告？ – stefanB
當連接關閉（'recv'返回0）時，您是否從epoll集中移除套接字？ –
@Joachim PileBorg我使用close（fd）是不夠的？謝謝。 – cemycc