CSocket接收大数据包问题

scsjhkxx 2018-05-25 10:40:32

现在发送端要发送一张图片数据大概是4，5M的样子，我是接收端，调用onreceive函数接收数据一次会收不全，但是Onreceive不会再次触发，所以我必须用GOTO函数手动回到recv函数那里再检测一次收到多少数据了，然后继续保存到缓存内，但是现在遇到一个很奇怪的问题，我必须在检测收到多少数据和goto回到检测数据中间加入一些延时操作或者是sleep，否则函数无法向下执行，但是我F10单步调试函数却依然可以向下执行，想问一下有人知道是为什么吗？函数如下:

void CMFCApplication2Dlg::RecvData(CServerSocket* pSocket)
{
char m_cbRecvBuf[819200];

memset(m_cbRecvBuf, 0, sizeof(char) * 819200);

int m_nRecvSize = 0;
recheckbuffer:
int nRecvSize = ::recv(*pSocket, m_cbRecvBuf + m_nRecvSize, 819200 - m_nRecvSize, 0);
m_nRecvSize += nRecvSize;
while (m_nRecvSize >= 4)
{
int t;
memcpy(&t, m_cbRecvBuf, 4);//前4byte得到header大小

if (m_nRecvSize < t + 4)
{
// 还不够拼凑出一个完整header
break;
}
char* m_cbRecvheaderBuf = new char[t];
CopyMemory(m_cbRecvheaderBuf, m_cbRecvBuf + 4, t);//将4byte后数据保存到缓存中
...................这里对header进行解码

int t2 = 0;
if (m_nRecvSize < t + 8)
{
// 还不够拼凑出一个完整body的大小数据
break;
}
memcpy(&t2, m_cbRecvBuf + t + 4, 4);//前4byte得到body的大小

Sleep(1);//必须要加一个延时或者是任意函数在中间才能让函数正常执行，这是为什么？？
if (m_nRecvSize < t + 8 + t2)// 还不够拼凑出一个完整body
{
goto recheckbuffer;
}
CopyMemory(m_DataBuf, m_cbRecvBuf + t + 8, t2);//拷贝到数据缓存处理
memset(m_cbRecvBuf, 0, sizeof(char) * 819200);
m_nRecvSize = 0;
}

...全文

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qq8533 2020-05-07

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1.重写OnReceive就是实现自己的业务逻辑 2.当socket的接收缓冲区有新数据时，OnReceive被调用。 当缓冲区空了以后，再有新数据以后，才会触发！假如你在连续的Receive，在这个过程中数据假如源源不断，是不会有OnReceive的。因此一般期望在一个WSAEWOULDBLOCK失败的Receive后，再等待onreceive 3.正确的做法是在OnReceive事件中只能调用一次的Receive，如果调用两次，就会因为此时还没有后续数据到达导致阻塞如果判断数据未接收完整需先将数据放在自定义的缓冲区内，然后等待下一次的OnReceive

scsjhkxx 2018-05-31

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解决了。。最笨的办法。。。Onreceive里面加个阻塞几毫秒每条信息都阻塞一下接收全了再调用recv函数去接收缓存，楼上建议的这些都谢谢啦我会去看的，目前是刚开始学习网络编程。

Eleven 2018-05-30

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你应该采用循环方式recv接收，每次都需要检查recv函数的返回值是多少，直到指定的数据字节。

smwhotjay 2018-05-30

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用win32 api socket 不用mfc的内裤。

赵4老师 2018-05-30

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https://bbs.csdn.net/topics/392372284

worldy 2018-05-29

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使用IOCP吧

走好每一步 2018-05-26

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CSocket不好用，自己写一个吧。

赵4老师 2018-05-25

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仅供参考：

//循环向a函数每次发送200个字节长度（这个是固定的）的buffer,
//a函数中需要将循环传进来的buffer，组成240字节（也是固定的）的新buffer进行处理，
//在处理的时候每次从新buffer中取两个字节打印
#ifdef _MSC_VER
    #pragma warning(disable:4996)
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifdef _MSC_VER
    #include <windows.h>
    #include <process.h>
    #include <io.h>
    #define  MYVOID             void
    #define  vsnprintf          _vsnprintf
#else
    #include <unistd.h>
    #include <sys/time.h>
    #include <pthread.h>
    #define  CRITICAL_SECTION   pthread_mutex_t
    #define  MYVOID             void *
#endif
//Log{
#define MAXLOGSIZE 20000000
#define MAXLINSIZE 16000
#include <time.h>
#include <sys/timeb.h>
#include <stdarg.h>
char logfilename1[]="MyLog1.log";
char logfilename2[]="MyLog2.log";
static char logstr[MAXLINSIZE+1];
char datestr[16];
char timestr[16];
char mss[4];
CRITICAL_SECTION cs_log;
FILE *flog;
#ifdef _MSC_VER
void Lock(CRITICAL_SECTION *l) {
    EnterCriticalSection(l);
}
void Unlock(CRITICAL_SECTION *l) {
    LeaveCriticalSection(l);
}
void sleep_ms(int ms) {
    Sleep(ms);
}
#else
void Lock(CRITICAL_SECTION *l) {
    pthread_mutex_lock(l);
}
void Unlock(CRITICAL_SECTION *l) {
    pthread_mutex_unlock(l);
}
void sleep_ms(int ms) {
    usleep(ms*1000);
}
#endif
void LogV(const char *pszFmt,va_list argp) {
    struct tm *now;
    struct timeb tb;

    if (NULL==pszFmt||0==pszFmt[0]) return;
    vsnprintf(logstr,MAXLINSIZE,pszFmt,argp);
    ftime(&tb);
    now=localtime(&tb.time);
    sprintf(datestr,"%04d-%02d-%02d",now->tm_year+1900,now->tm_mon+1,now->tm_mday);
    sprintf(timestr,"%02d:%02d:%02d",now->tm_hour     ,now->tm_min  ,now->tm_sec );
    sprintf(mss,"%03d",tb.millitm);
    printf("%s %s.%s %s",datestr,timestr,mss,logstr);
    flog=fopen(logfilename1,"a");
    if (NULL!=flog) {
        fprintf(flog,"%s %s.%s %s",datestr,timestr,mss,logstr);
        if (ftell(flog)>MAXLOGSIZE) {
            fclose(flog);
            if (rename(logfilename1,logfilename2)) {
                remove(logfilename2);
                rename(logfilename1,logfilename2);
            }
        } else {
            fclose(flog);
        }
    }
}
void Log(const char *pszFmt,...) {
    va_list argp;

    Lock(&cs_log);
    va_start(argp,pszFmt);
    LogV(pszFmt,argp);
    va_end(argp);
    Unlock(&cs_log);
}
//Log}
#define ASIZE    200
#define BSIZE    240
#define CSIZE      2
char Abuf[ASIZE];
char Cbuf[CSIZE];
CRITICAL_SECTION cs_HEX;
CRITICAL_SECTION cs_BBB;
struct FIFO_BUFFER {
    int  head;
    int  tail;
    int  size;
    char data[BSIZE];
} BBB;
int No_Loop=0;
void HexDump(int cn,char *buf,int len) {
    int i,j,k;
    char binstr[80];

    Lock(&cs_HEX);
    for (i=0;i<len;i++) {
        if (0==(i%16)) {
            sprintf(binstr,"%03d %04x -",cn,i);
            sprintf(binstr,"%s %02x",binstr,(unsigned char)buf[i]);
        } else if (15==(i%16)) {
            sprintf(binstr,"%s %02x",binstr,(unsigned char)buf[i]);
            sprintf(binstr,"%s  ",binstr);
            for (j=i-15;j<=i;j++) {
                sprintf(binstr,"%s%c",binstr,('!'<buf[j]&&buf[j]<='~')?buf[j]:'.');
            }
            Log("%s\n",binstr);
        } else {
            sprintf(binstr,"%s %02x",binstr,(unsigned char)buf[i]);
        }
    }
    if (0!=(i%16)) {
        k=16-(i%16);
        for (j=0;j<k;j++) {
            sprintf(binstr,"%s   ",binstr);
        }
        sprintf(binstr,"%s  ",binstr);
        k=16-k;
        for (j=i-k;j<i;j++) {
            sprintf(binstr,"%s%c",binstr,('!'<buf[j]&&buf[j]<='~')?buf[j]:'.');
        }
        Log("%s\n",binstr);
    }
    Unlock(&cs_HEX);
}
int GetFromRBuf(int cn,CRITICAL_SECTION *cs,struct FIFO_BUFFER *fbuf,char *buf,int len) {
    int lent,len1,len2;

    lent=0;
    Lock(cs);
    if (fbuf->size>=len) {
        lent=len;
        if (fbuf->head+lent>BSIZE) {
            len1=BSIZE-fbuf->head;
            memcpy(buf     ,fbuf->data+fbuf->head,len1);
            len2=lent-len1;
            memcpy(buf+len1,fbuf->data           ,len2);
            fbuf->head=len2;
        } else {
            memcpy(buf     ,fbuf->data+fbuf->head,lent);
            fbuf->head+=lent;
        }
        fbuf->size-=lent;
    }
    Unlock(cs);
    return lent;
}
MYVOID thdB(void *pcn) {
    char        *recv_buf;
    int          recv_nbytes;
    int          cn;
    int          wc;
    int          pb;

    cn=(int)pcn;
    Log("%03d thdB              thread begin...\n",cn);
    while (1) {
        sleep_ms(10);
        recv_buf=(char *)Cbuf;
        recv_nbytes=CSIZE;
        wc=0;
        while (1) {
            pb=GetFromRBuf(cn,&cs_BBB,&BBB,recv_buf,recv_nbytes);
            if (pb) {
                Log("%03d recv %d bytes\n",cn,pb);
                HexDump(cn,recv_buf,pb);
                sleep_ms(1);
            } else {
                sleep_ms(1000);
            }
            if (No_Loop) break;//
            wc++;
            if (wc>3600) Log("%03d %d==wc>3600!\n",cn,wc);
        }
        if (No_Loop) break;//
    }
#ifndef _MSC_VER
    pthread_exit(NULL);
#endif
}
int PutToRBuf(int cn,CRITICAL_SECTION *cs,struct FIFO_BUFFER *fbuf,char *buf,int len) {
    int lent,len1,len2;

    Lock(cs);
    lent=len;
    if (fbuf->size+lent>BSIZE) {
        lent=BSIZE-fbuf->size;
    }
    if (fbuf->tail+lent>BSIZE) {
        len1=BSIZE-fbuf->tail;
        memcpy(fbuf->data+fbuf->tail,buf     ,len1);
        len2=lent-len1;
        memcpy(fbuf->data           ,buf+len1,len2);
        fbuf->tail=len2;
    } else {
        memcpy(fbuf->data+fbuf->tail,buf     ,lent);
        fbuf->tail+=lent;
    }
    fbuf->size+=lent;
    Unlock(cs);
    return lent;
}
MYVOID thdA(void *pcn) {
    char        *send_buf;
    int          send_nbytes;
    int          cn;
    int          wc;
    int           a;
    int          pa;

    cn=(int)pcn;
    Log("%03d thdA              thread begin...\n",cn);
    a=0;
    while (1) {
        sleep_ms(100);
        memset(Abuf,a,ASIZE);
        a=(a+1)%256;
        if (16==a) {No_Loop=1;break;}//去掉这句可以让程序一直循环直到按Ctrl+C或Ctrl+Break或当前目录下存在文件No_Loop
        send_buf=(char *)Abuf;
        send_nbytes=ASIZE;
        Log("%03d sending %d bytes\n",cn,send_nbytes);
        HexDump(cn,send_buf,send_nbytes);
        wc=0;
        while (1) {
            pa=PutToRBuf(cn,&cs_BBB,&BBB,send_buf,send_nbytes);
            Log("%03d sent %d bytes\n",cn,pa);
            HexDump(cn,send_buf,pa);
            send_buf+=pa;
            send_nbytes-=pa;
            if (send_nbytes<=0) break;//
            sleep_ms(1000);
            if (No_Loop) break;//
            wc++;
            if (wc>3600) Log("%03d %d==wc>3600!\n",cn,wc);
        }
        if (No_Loop) break;//
    }
#ifndef _MSC_VER
    pthread_exit(NULL);
#endif
}
int main() {
#ifdef _MSC_VER
    InitializeCriticalSection(&cs_log);
    InitializeCriticalSection(&cs_HEX);
    InitializeCriticalSection(&cs_BBB);
#else
    pthread_t threads[2];
    int threadsN;
    int rc;
    pthread_mutex_init(&cs_log,NULL);
    pthread_mutex_init(&cs_HEX,NULL);
    pthread_mutex_init(&cs_BBB,NULL);
#endif
    Log("Start===========================================================\n");

    BBB.head=0;
    BBB.tail=0;
    BBB.size=0;

#ifdef _MSC_VER
    _beginthread((void(__cdecl *)(void *))thdA,0,(void *)1);
    _beginthread((void(__cdecl *)(void *))thdB,0,(void *)2);
#else
    threadsN=0;
    rc=pthread_create(&(threads[threadsN++]),NULL,thdA,(void *)1);if (rc) Log("%d=pthread_create %d error!\n",rc,threadsN-1);
    rc=pthread_create(&(threads[threadsN++]),NULL,thdB,(void *)2);if (rc) Log("%d=pthread_create %d error!\n",rc,threadsN-1);
#endif

    if (!access("No_Loop",0)) {
        remove("No_Loop");
        if (!access("No_Loop",0)) {
            No_Loop=1;
        }
    }
    while (1) {
        sleep_ms(1000);
        if (No_Loop) break;//
        if (!access("No_Loop",0)) {
            No_Loop=1;
        }
    }
    sleep_ms(3000);
    Log("End=============================================================\n");
#ifdef _MSC_VER
    DeleteCriticalSection(&cs_BBB);
    DeleteCriticalSection(&cs_HEX);
    DeleteCriticalSection(&cs_log);
#else
    pthread_mutex_destroy(&cs_BBB);
    pthread_mutex_destroy(&cs_HEX);
    pthread_mutex_destroy(&cs_log);
#endif
    return 0;
}

赵4老师 2018-05-25