C sockets receive file

Question

I'm developing very simple ftp client. I have created a data connection sockets, but I can't transfer file successfully:

FILE *f = fopen("got.png", "w");
int total = 0;
while (1){      
    memset(temp, 0, BUFFSIZE);
    int got = recv(data, temp, sizeof(temp), 0);

    fwrite(temp, 1, BUFFSIZE, f);
    total += got;

    if (total == 1568){
    break;
    }
}
fclose(f);

BUFFSIZE = 1568

I know that my file is 1568 bytes size, so I try to download it just for a test. Everything is file when I try to download .xml or .html files, but nothing good happens when I try to download png or avi files. Simply original file size is 1568 but got.png file size is 1573. I can't figure out what might cause that.

EDIT:

I have modified my code, so now it looks like (it can accept any file size):

FILE *f = fopen("got.png", "w");
    while (1){
        char* temp = (char*)malloc(BUFFSIZE);
        int got = recv(data, temp, BUFFSIZE, 0);

        fwrite(temp, 1, got, f);

        if (got == 0){
            break;
        }
    }
    fclose(f);

Still received file is 2 bytes too long.

Answer 1

You are opening the file in text mode, so bare CR/LF characters are going to get translated to CRLF pairs when written to the file. You need to open the file in binary mode instead:

FILE *f = fopen("got.png", "wb");

Answer 2

You are always writing a whole buffer even if you have received only a partial one. This is the same problem with ~50% of all TCP questions.

The memset is not necessary. And I hope that temp is an array so that sizeof(temp) does not evaluate to the native pointer size. Better use BUFFSIZE there as well.

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Seeing your edit, after fixing the first problem there is another one: Open the file in binary mode.