--- tiny.origin.c	2017-11-09 02:57:43.651936112 +0000
+++ tiny.6.c	2017-11-09 02:57:43.651936112 +0000
@@ -13,6 +13,8 @@
 void clienterror(int fd, char *cause, char *errnum,
     char *shortmsg, char *longmsg);
 
+void echo(int connfd);
+
 int main(int argc, char **argv)
 {
   int listenfd, connfd;
@@ -33,11 +35,24 @@
     Getnameinfo((SA *) &clientaddr, clientlen, hostname, MAXLINE,
         port, MAXLINE, 0);
     printf("Accepted connection from (%s, %s)\n", hostname, port);
-    doit(connfd);                                             //line:netp:tiny:doit
+    echo(connfd);
     Close(connfd);                                            //line:netp:tiny:close
   }
 }
 
+void echo(int connfd) {
+  size_t n;
+  char buf[MAXLINE];
+  rio_t rio;
+
+  Rio_readinitb(&rio, connfd);
+  while ((n = Rio_readlineb(&rio, buf, MAXLINE)) != 0) {
+    if (strcmp(buf, "\r\n") == 0)
+      break;
+    Rio_writen(connfd, buf, n);
+  }
+}
+
 /*
  * doit - handle one HTTP request/response transaction
  */