Pixiv に telnet でログインする

[yuanying@Felix] ~/Projects
$ telnet www.pixiv.net 80 
Trying 122.220.12.37...
Connected to www.pixiv.net.
Escape character is '^]'.
POST /index.php HTTP/1.1
Host: www.pixiv.net
Content-Type: application/x-www-form-urlencoded
Content-Length: 61

mode=login&pixiv_id=*****&pass=******&submit.x=95&submit.y=13

10/1あたりから、mode=login とかいうパラメータが増えたっぽい。