你好，我建了两个socket，端口不同，但是有一个recvform接收不到数据，请问应该怎样修改？

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热心网友

不知道哪里不对...你对比一下.看有没有缺的吧

#include <stdio.h>
#include <string.h>
#include <Winsock2.h>
#include <ws2tcpip.h>

#pragma comment(lib, "Ws2_32.lib")

typedef struct SktInfoTag
{
int skt;
unsigned int ip;
unsigned short port;
char buf[2048];
int bufsize;
}SktInfo;

static int thread_proc( LPVOID param );

SktInfo siInfo;

void main()
{
WSADATA wsaData;
unsigned long threadflag;
int ret = 0;
unsigned long unblock =1;
void* thrd = INVALID_HANDLE_VALUE;

ret = WSAStartup(MAKEWORD(2,2), &wsaData);

siInfo.ip = inet_addr("192.168.0.1");
siInfo.port = 5001;
siInfo.bufsize = 2048;

//创建socket
siInfo.skt = socket(AF_INET, SOCK_DGRAM, 0);
if( siInfo.skt == -1 )
{
printf("socket create failed!\n");
goto END;
}

//非阻塞
ioctlsocket(siInfo.skt, FIONBIO, &unblock);

if( 224 <= *((unsigned char*)&siInfo.ip) && *((unsigned char*)&siInfo.ip) <= 240 )
{
struct sockaddr_in addr;
struct ip_mreq mreq;
int ttl = 127;
int flag = 1;

memset(&addr, 0, sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = INADDR_ANY;
addr.sin_port = siInfo.port;

//绑定本地接收端口
ret = bind( siInfo.skt, (struct sockaddr*)&addr, sizeof(addr));
if(ret < 0)
{
printf("bind socket failed!\n");
goto END;
}

memset(&mreq, 0, sizeof(mreq));
mreq.imr_multiaddr.s_addr = siInfo.ip;
mreq.imr_interface.s_addr = INADDR_ANY;

//设置缺省参数
setsockopt(siInfo.skt, IPPROTO_IP, IP_MULTICAST_TTL, (char*)&ttl, sizeof(ttl));
setsockopt(siInfo.skt, IPPROTO_IP, IP_MULTICAST_LOOP, (char*)flag, sizeof(flag));

//加入组播
ret = setsockopt(siInfo.skt, IPPROTO_IP, IP_ADD_MEMBERSHIP,(char*)&mreq, sizeof(mreq));
if( ret < 0 )
{
printf("setsockopt socket failed!\n");
goto END;
}
}
else
{
struct sockaddr_in addr;

memset(&addr, 0, sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = siInfo.ip;
addr.sin_port = siInfo.port;

//绑定本地接收地址端口
ret = bind(siInfo.skt, (struct sockaddr*)&addr, sizeof(addr));
if( ret < 0 )
{
printf("bind socket failed!\n");
goto END;
}
}

//创建接收线程
if( INVALID_HANDLE_VALUE == (thrd = CreateThread(NULL, 1024, (LPTHREAD_START_ROUTINE)thread_proc, (LPVOID)&siInfo, 0, &threadflag)) )
{
goto END;
}

while(1)
{
Sleep(200);
}

END:
if( thrd != INVALID_HANDLE_VALUE )
{
CloseHandle(thrd);
thrd = NULL;
}
}

int thread_proc( LPVOID param )

{
fd_set rset;
int ret = 0;
int size = 0;
SktInfo* info = (SktInfo*)¶m;
struct sockaddr_in from;
int slen = sizeof(from);
struct timeval tv;
unsigned char *recvip;
unsigned short *recvport;
int timeout = 100;

if( info->skt == -1)
goto EXIT_END;

tv.tv_sec = timeout/1000;
tv.tv_usec = (timeout%1000)*1000;

while(1)
{
memset(&from, 0, sizeof(from));

FD_ZERO(&rset);
FD_SET(info->skt, &rset);

//检测可接收
ret = select(info->skt+1, &rset, NULL, NULL, &tv);
if( ret < 0 )
{
goto SLEEP;
}

if( FD_ISSET(info->skt, &rset))
{
//接收数据
size = recvfrom(info->skt, info->buf, info->bufsize, 0, (struct sockaddr*)&from, &slen);
if( size <= 0 )
{
goto EXIT_END;
}

recvip = (unsigned char*)(&from.sin_addr.S_un.S_addr);
recvport = &from.sin_port;

printf("recv form %d.%d.%d.%d:%d %d byte data\n", recvip[0], recvip[1], recvip[2], recvip[3], ntohs(*recvip), size);
}

SLEEP:
Sleep(5);
}

EXIT_END:
return -1;

}来自：求助得到的回答

热心网友

为啥要端口不同?端口不同 肯定收不到啊,端口要一致才能收到

热心网友

按照理解，你的SOCKET是UDP的了，你就发了一个包，怎么可能会接收到两个包呢。还有你发送给的哪个端口哪个与之绑定的SOCKET才能接到。