/* TODO: add dns timer */
#include "sbalance.h"
#include "sbdns.h"
#include "sbconstant.h"
#include "sbproxy.h"
#include "sbproxy.h"
#include "sblist.h"
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include <netdb.h>
#include <sys/types.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <sys/epoll.h>
#include <netinet/tcp.h>
#include <arpa/inet.h>
#include <errno.h>

#define SB_DNS_TIMEOUT_TIME		2500
#define SB_DNS_HASH_SLOTS		11

/* fixbug: client want to finish a keepalive, but in get request function will treat 
   the normal finish event an error */

int sb_proxy_send_request_to_server_event(struct sb_cycle_env *env, struct sb_event *ev);
int sb_proxy_accept_event(struct sb_cycle_env *env, struct sb_event *ev);
int sb_proxy_get_request_event(struct sb_cycle_env *env, struct sb_event *ev);
int sb_proxy_test_connect_http_server_complete_event(struct sb_cycle_env *env, struct sb_event *ev);
int sb_proxy_send_to_client_connectserverok_event(struct sb_cycle_env *env, struct sb_event *ev);

int sb_proxy_dns_request(struct sb_cycle_env *env, struct sb_session *sess, int flag);
int sb_proxy_dns_recv_resp(struct sb_cycle_env *env);

static char *CRLF = "\r\n";
static char line_buf[MAXIOBUFLEN];

/* @RETURN  callback Handler */
void sb_dns_done_handler(struct sb_cycle_env *env, struct sb_session *sess)
{
	int rc;
	int ip_len;
	int len;

	if (sess->status == SB_DNS_STATUS_OK) {	/* DESTORYED OR OK */
		len = sizeof(sess->server.net_address.ip);
		rc = sb_proxy_connect_http_server(env, sess);
		if (rc == SB_ERROR) {
			ErrorOutput("proxy connect failed, session finish");
			(void)sb_finish_session(env, sess);
		} 
	}
	else {
		if (sess->host_is_ip) {
			(void)sb_finish_session(env, sess);
			return;
		}

		/* try to update */
		sb_proxy_dns_request(env, sess, 1);

		ErrorOutput("proxy dns request failed, session finish");
		(void)sb_finish_session(env, sess);
	}
}

/* @RETURN 1. SB_OK	2. SB_ERROR	3. SB_AGAIN(dns parsing, when complete, sb_dns_done_handler be called, occur in new request)*/
int sb_parse_http_request_header(struct sb_session *sess)
{
	unsigned int line_len;
	char *buf = sess->cs_buf;
	char *start_ptr = buf + sess->current_offset;
	char *end_ptr = NULL;
	int err;
	char *c = NULL;
	struct sb_connection *server_conn = NULL;
	int i = 0, j;
	int len, host_len;
	int del_len = 0;

	server_conn = &sess->server;

	while (start_ptr < start_ptr + sess->cs_used) {

		end_ptr = NULL;
		for (c = start_ptr; c <= start_ptr + sess->cs_used - 2; c++) {
			if (*c == '\r' && *(c + 1) == '\n' ) {
				end_ptr = c;
				break;
			}
		}

		if (end_ptr == NULL) {
			break;
		}

		line_len = end_ptr - start_ptr;

		/* first line */
		if (sess->current_offset == 0) {
			if (! (	memcmp(start_ptr, "GET", 3) == 0 || 
						memcmp(start_ptr, "POST", 4) == 0 ||
						memcmp(start_ptr, "PUT", 3) == 0 ||
						memcmp(start_ptr, "HEAD", 4) == 0 || 
						memcmp(start_ptr, "TRACE", 5) == 0 || 
						memcmp(start_ptr, "CONNECT", 7) == 0 || 
						memcmp(start_ptr, "DELETE", 6) == 0 )
			   ) {

				ErrorOutput("http request method error");
				return SB_ERROR;	
			}
		}

		if (start_ptr == end_ptr) {
			sess->crlf = 1;	
		}
		else if (line_len >= 7 && memcmp(start_ptr, "CONNECT", 7) == 0) {
			sess->http_connect_method = 1;	
		}
		else if (line_len >= 15 && memcmp(start_ptr, "Content-Length:", 15) == 0) {
			char *tmp_start = NULL;  
			char *tmp_end = NULL;  
			char tmp_buf[32];

			for (tmp_start = start_ptr + 15; tmp_start < end_ptr && (*tmp_start == ' ' || *tmp_start== '\t'); tmp_start++ ){}
			for (tmp_end = end_ptr - 1; tmp_end >= tmp_start && (*tmp_end == ' ' || *tmp_end== '\t'); tmp_end--) {}

			if (tmp_start <= tmp_end) {
				memcpy(tmp_buf, tmp_start, tmp_end - tmp_start + 1);	
				tmp_buf[tmp_end - tmp_start + 1] = '\0';
				sess->content_length = (unsigned int)atoi(tmp_buf);
			}
		}
		else if (line_len >= 6 && memcmp(start_ptr, "Proxy-", 6) == 0) {
			/* 6: strlen("Proxy-") */
			del_len = 6;
			memmove(start_ptr, start_ptr + 6,  sess->cs_used - sess->current_offset - del_len);
		}
		else if (line_len >= 5 && memcmp(start_ptr, "Host:", 5) == 0) {
			char *tmp_start = NULL;
			char *tmp_end = NULL;
			char tmp_buf[256];
			int colon = 0;
			int is_origin_ip = 1;

			for (tmp_start = start_ptr + 5; tmp_start < end_ptr && (*tmp_start == ' ' || *tmp_start== '\t'); tmp_start++ ){}
			for (tmp_end = end_ptr - 1; tmp_end >= tmp_start && ( *tmp_end == ' ' || *tmp_end== '\t'); tmp_end--) {}

			/* already dns the host ip */
			if (server_conn->net_address.ip[0] == '\0') {
				if (tmp_start < tmp_end) {
					host_len = tmp_end - tmp_start + 1;
					sess->host_is_ip = 0;

					j = host_len;
					for (i = 0; i < host_len; i++) {
						if (tmp_start[i] != '.' && !(tmp_start[i] >= '0' && tmp_start[i] <= '9') && tmp_start[i] != ':') {
							is_origin_ip = 0;
							break;

						} else if (tmp_start[i] == ':') {
							colon++;
							j = i;
						}
					}
					if (colon >= 2) {
						ErrorOutput("request header not correct");
						return SB_ERROR;
					}

					if (is_origin_ip == 1) {	/* origin ip */
						if (colon == 1) {
							/* ip address */
							memcpy(server_conn->net_address.ip, tmp_start, j);
							server_conn->net_address.ip[j] = '\0';

							*(tmp_end + 1) = '\0';
							/* port */
							server_conn->net_address.port = atoi(tmp_start + j + 1);
						}
						else {	/* colon = 0 */
							memcpy(server_conn->net_address.ip, tmp_start, host_len);
							server_conn->net_address.ip[host_len] = '\0';
							server_conn->net_address.port = sess->http_connect_method ? 443 : 80;
						}
						sess->host_is_ip = 1;

					} else {	
						sess->host[0] = '\0';
						if (colon == 1) {
							memcpy(sess->host, tmp_start, j);
							sess->host[j] = '\0';

							*(tmp_end + 1) = '\0';
							server_conn->net_address.port = atoi(tmp_start + j + 1);

						} else {
							memcpy(sess->host, tmp_start, host_len);
							sess->host[host_len] = '\0';
							server_conn->net_address.port = sess->http_connect_method ? 443 : 80;

						}
					}

				}
				else {
					return SB_ERROR;
				}
			} else {
				/* do nothing */
			}
		}

		sess->current_offset += (line_len + 2 - del_len);
		sess->cs_used -= del_len;
		del_len = 0;

		start_ptr = sess->cs_buf + sess->current_offset;

		if (sess->crlf == 1)
			break;
	}

	return SB_OK;
}

/* start with no event handler both in server and client */
int sb_proxy_connect_http_server_ok(struct sb_cycle_env *env, struct sb_session *sess)
{
	struct sb_connection *ser_c;
	struct sb_connection *cli_c;
	const static char CONNECTMETHOD_CONNECTSEREROK[] = "HTTP/1.1 200 Connection Established\r\n\r\n";
	const static char CONNECTMETHOD_CONNECTSEREROK_LEN = sizeof(CONNECTMETHOD_CONNECTSEREROK) - 1;

	ser_c = &sess->server;
	cli_c = &sess->client;

	if (sb_event_is_active(&ser_c->write)) {
		if (sb_del_write_event(&ser_c->write)) {
			ErrorOutput("connect server ok, but delete write event failed\n");
			return SB_ERROR;
		}
	}

	/* client use connect medhod want to build tcp tunnel */	
	if (sess->http_connect_method) {
		/*
		   if (sess->request_times || sess->sc_used) {
		   FatalOutput("http connect method request can't use previous tcp channel");
		//return SB_ERROR;
		}
		 */

		memcpy(sess->sc_buf + sess->sc_used, CONNECTMETHOD_CONNECTSEREROK, CONNECTMETHOD_CONNECTSEREROK_LEN); 
		sess->sc_used += CONNECTMETHOD_CONNECTSEREROK_LEN;

		if (!sb_event_is_active(&cli_c->write)) {
			sb_add_write_event(&cli_c->write, sb_proxy_send_to_client_connectserverok_event);
		}
	}
	else {
		/* server's read handler always sb_transfer_read_event */
		/* client's write handler always sb_transfer_write_event, but add when has sending data */
		sb_add_read_event(&ser_c->read, sb_transfer_read_event );

		(void)sb_proxy_start_request(env, sess);
	}

	sess->request_times++;

	return SB_OK;
}

/* EVENT HANDLER: send the request to http server
   if send done, add client's write handler sb_transfer_write_event and server's read handler sb_transfer_read_event 
   and delete server write handler 
 */
int sb_proxy_send_request_to_server_event(struct sb_cycle_env *env, struct sb_event *ev)
{
	int err;
	struct sb_connection *ser_c = NULL;
	struct sb_connection *cli_c = NULL;
	struct sb_session *sess = NULL;

	ser_c = (struct sb_connection*)ev->data;
	sess= ser_c->session;
	cli_c = &sess->client; 

	err = sb_send(ser_c);
	if (err == SB_OK) {		/* Send done, change handler */	
		if (cli_c->read.shutdown) {
			InfoOutput("client[%s]:[%d]--server[%s]:[%d] finish", sess->client.net_address.ip,
					sess->client.net_address.port, sess->server.net_address.ip, sess->server.net_address.port);

			(void)sb_finish_session(env, sess);
			return SB_OK;
		}

		/* now we should, recv server's data and send to client */
		/* write will delete auto */
		//sb_del_write_event(&ser_c->write);

		/* copy next request's data to cs_buf */
		memmove(sess->cs_buf, sess->cs_buf + sess->current_offset, sess->cs_used_remain);
		sess->current_offset = 0;
		sess->content_length = 0;
		sess->cs_used_remain = 0;
		sess->crlf = 0;

		/* get client request */
		sb_add_read_event(&cli_c->read, sb_proxy_get_request_event);

		/***
		  sb_del_write_event(&ser_c->write);
		  if (!sb_event_is_active(&cli_c->write)) {
		  sb_add_write_event(&cli_c->write, sb_transfer_write_event );
		  }
		 ***/

		return SB_OK;
	}
	else if (err == SB_AGAIN) {
		return SB_OK;
	}
	else {
		ErrorOutput("client[%s]:[%d]--server[%s]:[%d] send error", sess->client.net_address.ip,
				sess->client.net_address.port, sess->server.net_address.ip, sess->server.net_address.port);
		(void)sb_finish_session(env, sess);
		return SB_ERROR;
	}
}

/* EVENT HANDLER: proxy send client "Established" response after connect server ok(when request use connect method) */
/* notice: because this event handler call another event handler, so in the event handler will not finish session
   and when send all data, new ssl session */
int sb_proxy_send_to_client_connectserverok_event(struct sb_cycle_env *env, struct sb_event *ev)
{
	int rc = 0;
	struct sb_connection *cli_c;
	struct sb_connection *ser_c;
	struct sb_session *sess;

	cli_c = (struct sb_connection*)ev->data;
	sess = cli_c->session;
	ser_c = &sess->server;

	/* manually call another event handler */
	rc = sb_transfer_write_event(env, ev);
	if (rc == SB_OK) {
		/* when data send done */
		sess->cs_used = 0;
		sb_add_read_event(&ser_c->read, sb_transfer_read_event );
		sb_add_read_event(&cli_c->read, sb_transfer_read_event );

		/** delete write auto in sb_transfer_write_event
		  if (sb_event_is_active(&cli_c->write)) {
		  sb_del_write_event(&cli_c->write);
		  }
		 **/
	}

	return rc;
}

/* EVENT HANDLER: server write handler*/
int sb_proxy_test_connect_http_server_complete_event(struct sb_cycle_env *env, struct sb_event *ev)
{
	int err = 0, len = sizeof(int);
	int r;
	struct sb_connection *c;
	struct sb_session *sess;

	c = (struct sb_connection*)ev->data;
	sess = c->session;

	r = getsockopt(c->sockfd, SOL_SOCKET, SO_ERROR, (void *) &err, &len);

	if (r || err) {
		(void)sb_finish_session(env, sess);
		ErrorOutput("cli[%s]-ser[%s] make transfer link failed, r[%d] errno[%d] err[%d]", sess->client.net_address.ip, sess->server.net_address.ip, r, errno, err);
		return SB_ERROR;
	}
	else {
		/* ok, finally success */
		err = sb_proxy_connect_http_server_ok(env, sess);
		if (err) {
			(void)sb_finish_session(env, sess);
			ErrorOutput("client[%s]-server[%s] connect ok,but init env failed", sess->client.net_address.ip, sess->server.net_address.ip);
			return SB_ERROR;
		}
		else {
			DebugOutput("client[%s]-server[%s]:[%d] make transfer link success", sess->client.net_address.ip, sess->server.net_address.ip, sess->server.net_address.port);
			return SB_OK;
		}
	}
}

int sb_proxy_start_request(struct sb_cycle_env *env, struct sb_session *sess)
{
	/* 1. stop recv browser's data (delte client's read event)
	   2. try connect http server 
	   3. copy cs_buf_tmp to cs_buf(completely request) and clear completely request from cs_buf
	 */
	struct sb_connection *in;
	struct sb_connection *out;
	struct sockaddr_in addr;
	struct sb_event *we;

	in = &sess->client;
	out = &sess->server;

	/* activate server's write, because keepalive allow one tcp channel can exchange mutiple request and response */	
	if (sb_event_is_active(&out->write)) 
		sb_del_write_event(&out->write);

	sb_add_write_event(&out->write, sb_proxy_send_request_to_server_event );

	return SB_OK;
}

/* init socket, try connect server */
int sb_proxy_connect_http_server(struct sb_cycle_env *env, struct sb_session *sess)
{
	int err, n, fd;
	struct sb_connection *in;
	struct sb_connection *out;
	struct sockaddr_in addr;
	struct sb_event *we;
	int addr_len;

	in = &sess->client;
	out = &sess->server;

	we = &out->write;

	/* let's connect server */
	if ((fd = socket(AF_INET, SOCK_STREAM, 0)) < 0 ) {
		if (errno == EMFILE || errno == ENFILE) {
			/* delay accept */
			ErrorOutput("too many fd, access system limit, ip[%s]'s request is cut", sess->client.net_address.ip);
		}
		else {
			ErrorOutput("connect server, get socket fd failed, ip[%s]'s request is cut", sess->client.net_address.ip);
		}

		return SB_ERROR;
	}

	out->sockfd = fd;

	memset(&addr, 0x00, sizeof(addr));
	addr.sin_family = AF_INET;
	addr.sin_port = htons(out->net_address.port);
	if (inet_pton(AF_INET, out->net_address.ip, &addr.sin_addr.s_addr) != 1) {
		ErrorOutput("inet_pton failed ip[%s],errno[%d]", out->net_address.ip, errno);
		sess->why_finish = FINISH_REASON_SYSTEMCALLERR;
		return SB_ERROR;
	}
	addr_len = sizeof(struct sockaddr_in);
	memcpy(&out->net_address.sockaddr, &addr, addr_len);

	sb_set_nonblocking(out->sockfd);
	sb_set_reuseaddr(out->sockfd, 1);
	sb_set_tcpkeepalive(out->sockfd);

	if (connect(out->sockfd, (struct sockaddr*)&addr, sizeof(addr)) == -1) {
		if (errno != EINPROGRESS) {
			ErrorOutput("connect server[%s] failed, errno[%d]", sess->server.net_address.ip, errno);

			sess->why_finish = FINISH_REASON_CONNECTSERVERERR;
			return SB_CONNECTERR;
		}
		/* can't know the connect result
		   so register the server's read event and set handler */
		else if (errno == EINPROGRESS) {
			err = sb_add_write_event(we, sb_proxy_test_connect_http_server_complete_event );
			if (err) {
				ErrorOutput("connect ip[%s]:port[%d] add write event failed, errno[%d]", out->net_address.ip, out->net_address.port, errno);
				sess->why_finish = FINISH_REASON_PROCESSEVENTERR;
				return SB_ERROR;
			}

			return SB_AGAIN;
		}
	} else { /* connect success */
		err = sb_proxy_connect_http_server_ok(env, sess);
		if (err) {
			ErrorOutput("client[%s]-server[%s] connect ok,but init env failed", sess->client.net_address.ip, sess->server.net_address.ip);
			return SB_ERROR;
		}
		else {
			InfoOutput("client[%s]:[%d]--[%d]local[%d]--server[%s]:[%d] link success", sess->client.net_address.ip,
					sess->client.net_address.port, sess->client.sockfd,sess->server.sockfd,
					sess->server.net_address.ip, sess->server.net_address.port);
			return SB_OK;
		}
	}
}

struct sb_session* sb_proxy_fork_session(struct sb_cycle_env *env, struct sb_session *sess)
{
	InfoOutput("client[%s]:[%d]--[%d]local[%d]--server[%s]:[%d] fork session", sess->client.net_address.ip,
			sess->client.net_address.port, sess->client.sockfd,sess->server.sockfd,
			sess->server.net_address.ip, sess->server.net_address.port);
	struct sb_session *new_session;
	struct sb_connection *cli_c;
	struct sb_connection *ser_c;
	struct sb_event *cli_re;
	struct sb_event *cli_we;
	struct sb_event *ser_re;
	struct sb_event *ser_we;

	/* try two times */
	new_session = sb_get_session(env);
	if (new_session == NULL) {
		new_session = sb_get_session(env);
	}
	if (new_session == NULL) {
		return NULL;
	}

	memcpy(new_session, sess, sizeof(struct sb_session));

	cli_c = &new_session->client;
	ser_c = &new_session->server;
	cli_c->session = new_session;
	ser_c->session = new_session;

	cli_re = &cli_c->read;
	cli_re->data = cli_c;

	cli_we = &cli_c->write;
	cli_we->data = cli_c;

	ser_re = &ser_c->read;
	ser_re->data = ser_c;

	ser_we = &ser_c->write;
	ser_we->data = ser_c;

	/** not need event and timer
	  if (sb_event_is_active(&sess->client.read)) {
	  sb_add_read_event(cli_re, sess->client.read.handler);
	  }
	  if (sb_event_is_active(&sess->server.read)) {
	  sb_add_read_event(ser_re, sess->server.read.handler);
	  }
	  if (sb_event_is_active(&sess->client.write)) {
	  sb_add_write_event(cli_we, sess->client.write.handler);
	  }   
	  if (sb_event_is_active(&sess->server.write)) {
	  sb_add_write_event(ser_we, sess->server.write.handler);
	  }

	  if (sess->client.read.in_timer_set) {
	  sb_timer_push_event(cli_re);
	  }
	  if (sess->client.write.in_timer_set) {
	  sb_timer_push_event(cli_we);
	  }
	  if (sess->server.read.in_timer_set) {
	  sb_timer_push_event(ser_re);
	  }                             
	  if (sess->server.write.in_timer_set) {
	  sb_timer_push_event(ser_we);
	  }
	 **/

	return new_session;
}

/* special use for http proxy's CONNECT method, just finish server side
   client side will be held by new forked session */
int sb_finish_session_with_opening_client(struct sb_cycle_env *env, struct sb_session *sess)
{
	struct sb_connection *ser_c;
	struct sb_connection *cli_c;

	if (sess->had_finish){
		return SB_OK;
	}

	sess->had_finish = 1;
	cli_c = &sess->client;
	ser_c = &sess->server;

	/* unregister event */
	if (sb_event_is_active(&cli_c->read)) {
		sb_del_read_event(&cli_c->read);
	}
	if (sb_event_is_active(&cli_c->write)) {
		sb_del_write_event(&cli_c->write);
	}

	if (sb_event_is_active(&ser_c->read)) {
		sb_del_read_event(&ser_c->read);
	}
	if (sb_event_is_active(&ser_c->write)) {
		sb_del_write_event(&ser_c->write);
	}

	/* can't close client's sockfd!!! */

	if (sess->server.sockfd > 0) {
		close(sess->server.sockfd);
		sess->server.sockfd = 0;
	}

	/* delete timer */
	if (cli_c->read.in_timer_set) {
		sb_timer_pop_event(&cli_c->read);
	}
	if (cli_c->write.in_timer_set) {
		sb_timer_pop_event(&cli_c->write);
	}
	if (ser_c->read.in_timer_set) {
		sb_timer_pop_event(&ser_c->read);
	}
	if (ser_c->write.in_timer_set) {
		sb_timer_pop_event(&ser_c->write);
	}

	/* mv session from active list to reuse list */
	sb_list_delete_session(&env->active_session_list, sess);
	env->active_session_num--;
	sb_list_push_session(&env->new_reuse_session_list, sess);
	env->reuse_sessoion_num++;

	return SB_OK;
}

/* EVENT HANDLER: client read */
int sb_proxy_get_request_event(struct sb_cycle_env *env, struct sb_event *ev)
{
	int err;
	struct sb_connection *in;
	struct sb_connection *out;
	struct sb_session *sess;
	struct sb_session *new_sess;
	int r, rc;
	int content_len;

	in = ev->data;
	sess = in->session;
	out = &sess->server;

	/* @RETURN: 1. SB_BUFNOTENOUGH          2. SB_AGAIN     3. SB_ERROR(errno)      4. SB_DONE */
	rc = sb_recv(in);

	if (rc == SB_DONE) {
		/* finish the session */
		/* fixbug: when client use shutdown(SHUT_WR), client will not send data, 
		   but want to recv data from server, so we can't finish whole session. Try send data to client */
		/* (void)sb_finish_session(env, sess);	*/

		in->read.shutdown = 1;
		InfoOutput("[%s] request want to finish", in->net_address.ip);
	}

	if(rc == SB_BUFNOTENOUGH) { 
		/* buffer not enough */
		(void)sb_finish_session(env, sess);
		ErrorOutput("[%s] request too long", in->net_address.ip);

		return SB_ERROR;
	}
	else if (rc == SB_ERROR) {
		(void)sb_finish_session(env, sess);	
		ErrorOutput("[%s] request error!", in->net_address.ip);

		return SB_ERROR;
	}
	else {	/* SB_AGAIN or SB_DONE */
		if (sess->cs_used - sess->current_offset >= 2  && sess->crlf == 0) {
			if ((rc = sb_parse_http_request_header(sess)) == SB_ERROR) {	/* maybe SB_AGAIN */
				ErrorOutput("sessionid[%lu] sb_parse_http_request_header failed", sess->sessionid);
				(void)sb_finish_session(env, sess);	
				return SB_ERROR;
			}
		}

		if (sess->crlf == 1) {
			//memcpy(sess->cs_buf+sess->cs_used, "Connection:Close", sizeof("Connection:Close") -1);
			//sess->cs_used +=  sizeof("Connection:Close") -1;

			/* delete client's read, and start server request */
			sb_del_read_event(&in->read);

			if (sess->http_connect_method) {
				FatalOutput("http connect method request can't use previous tcp channel");
				(void)sb_finish_session(env, sess);	
				ErrorOutput("[%s] request [%s] error!", in->net_address.ip, out->net_address.ip);
				return SB_ERROR;

				/* 1. fork session
				   2. discard origin http connection with server's side 
				 */
				new_sess = sb_proxy_fork_session(env, sess);
				if (new_sess == NULL) {
					(void)sb_finish_session(env, sess);
					ErrorOutput("get session failed!");

					return SB_ERROR;
				}
				(void)sb_finish_session_with_opening_client(env, sess);

				/* wow!!! now we are in new session, say bye bye with old http session */
				rc = sb_proxy_connect_http_server(env, new_sess);
				if (rc == SB_ERROR) {
					(void)sb_finish_session(env, new_sess);
					return SB_ERROR;
				}
			}

			if (sess->http_connect_method && sess->content_length) {
				ErrorOutput("connect method can't use contect length");
				(void)sb_finish_session(env, new_sess);
				return SB_ERROR;
			}

			if (sess->content_length) {
				content_len = sess->cs_used - sess->current_offset;				

				if (content_len < sess->content_length) {
					return SB_AGAIN;
				} else {
					sess->cs_used_remain = content_len - sess->content_length;
					sess->cs_used -= sess->cs_used_remain;
				}
			}
			if (sb_proxy_start_request(env, sess)) {
				(void)sb_finish_session(env, sess);
				return SB_ERROR;
			}
			sess->request_times++;
		} 
		else {
			if (in->read.shutdown) {
				if (sess->cs_used == 0) {
					ErrorOutput("[%s] request finish!", in->net_address.ip);
					rc = SB_OK;	
				}
				else {
					ErrorOutput("[%s] request finish before connect return and http request not correct", in->net_address.ip);
					rc = SB_ERROR;
				}

				(void)sb_finish_session(env, sess);

				return rc;
			}

			return SB_AGAIN;
		}
	}

	return SB_OK;
}

/* EVENT HANDLER(client read) */
int sb_proxy_get_new_request_event(struct sb_cycle_env *env, struct sb_event *ev)
{
	int err;
	struct sb_connection *in;
	struct sb_connection *out;
	struct sb_session *sess;
	int r, rc, rc2 = 0;
	int content_len;

	in = ev->data;
	sess = in->session;
	out = &sess->server;

	/* @RETURN: 1. SB_BUFNOTENOUGH          2. SB_AGAIN     3. SB_ERROR(errno)      4. SB_DONE */
	rc = sb_recv(in);

	if (rc == SB_DONE) {
		/* finish the session */
		/* fixbug: when client use shutdown(SHUT_WR), client will not send data,
		   but want to recv data from server, so we can't finish whole session. Try send data to client */
		/* (void)sb_finish_session(env, sess);  */

		in->read.shutdown = 1;
		InfoOutput("[%s] request finish before connect return", in->net_address.ip);
	}

	if(rc == SB_BUFNOTENOUGH) { 
		/* buffer not enough */
		(void)sb_finish_session(env, sess);
		ErrorOutput("[%s] request too long", in->net_address.ip);

		return SB_ERROR;
	}
	else if (rc == SB_ERROR) {
		(void)sb_finish_session(env, sess);	
		ErrorOutput("[%s] request error!", in->net_address.ip);

		return SB_ERROR;
	}
	else {	/* SB_DONE or SB_AGAIN */
		/* parse request */
		if (sess->cs_used - sess->current_offset >=2 && sess->crlf == 0) {
			if ((rc = sb_parse_http_request_header(sess)) == SB_ERROR) {	/* maybe SB_AGAIN */
				ErrorOutput("sessionid[%lu] sb_parse_http_request_header failed", sess->sessionid);
				(void)sb_finish_session(env, sess);	
				return SB_ERROR;
			}
		}

		if (sess->crlf == 1) {
			//memcpy(sess->cs_buf+sess->cs_used, "Connection:Close", sizeof("Connection:Close") -1);
			//sess->cs_used +=  sizeof("Connection:Close") -1;
			/* delete client's read, and start server request */
			sb_del_read_event(&in->read);

			if (sess->http_connect_method && sess->content_length) {
				ErrorOutput("connect method can't use content length");
				(void)sb_finish_session(env, sess);
				return SB_ERROR;
			}

			if (sess->content_length) {
				content_len = sess->cs_used - sess->current_offset;				
				if (content_len < sess->content_length) {
					return SB_AGAIN;

				} else if (content_len >= sess->content_length) {
					sess->cs_used_remain = content_len - sess->content_length;
					sess->cs_used -= sess->cs_used_remain;
				}
			}


			/* has server ip in host filed */
			if (sess->host_is_ip) {
				rc = sb_proxy_connect_http_server(env, sess);
				if (rc == SB_ERROR) {
					(void)sb_finish_session(env, sess);
					ErrorOutput("sessionid[%lu] sb_proxy_connect_http_server error", sess->sessionid);
					return SB_ERROR;
				}
			}
			else {
				/* need use dns */
				rc = sb_proxy_dns_request(env, sess, 0);
				if (rc == SB_ERROR) {
					ErrorOutput("sessionid[%lu] sb_proxy_dns_request error", sess->sessionid);
					(void)sb_finish_session(env, sess);    
					return SB_ERROR;
				}  
			}

		}
		else {
			if (in->read.shutdown) {
				ErrorOutput("[%s] request finish before connect return and http request not correct", in->net_address.ip);

				(void)sb_finish_session(env, sess);
				return SB_ERROR;
			}
		}
	}

	return SB_OK;
}

int sb_proxy_accept_event(struct sb_cycle_env *env, struct sb_event *ev)
{
	int err;
	int new_fd;
	struct sockaddr_in new_addr;
	int new_addr_len;
	struct sb_session *new_session;
	struct sb_listen *li;

	li = ev->data;
	while(1) {
		/* eat too many resource need wait */
		/**
		  if (env->accept_dalay_flag == 1)
		  break;
		 **/

		new_addr_len = sizeof(struct sockaddr_in);
		new_fd = accept(li->listen_fd, (struct sockaddr*)&new_addr, &new_addr_len);
		if (new_fd == -1) {
			if (errno == EAGAIN || errno == EWOULDBLOCK) {
				DebugOutput("accept EAGAIN");
			}
			else if (errno == EMFILE || errno == ENFILE) {
				/* need wait for a moment */
				/* delay accept */
				if (env->accept_delay_timeout > 0) {
					sb_push_accept_delay_timer(env);
				}
				ErrorOutput("too many fd, access the system limit");
			}
			else {
				ErrorOutput("listen ip[%s]-port[%d]-listen_fd[%d] accept failed",
						li->listen_address.ip,
						li->listen_address.port,
						li->listen_fd );
			}
			break;
		}
		else {
			struct sb_connection *cli_c;
			struct sb_connection *ser_c;
			struct sb_event *cli_re;
			struct sb_event *cli_we;
			struct sb_event *ser_re;
			struct sb_event *ser_we;

			/* try two times */
			new_session = sb_get_session(env);
			if (new_session == NULL) {
				new_session = sb_get_session(env);
			}
			if (new_session == NULL) {
				ErrorOutput("get session failed");
				/* close the new socket */
				/* can't get session, need wait for a moment */
				close(new_fd);
				break;
			}

			cli_c = &new_session->client;
			cli_c->connect_type = CONNECT_TYPE_CLIENT;
			ser_c = &new_session->server;
			ser_c->connect_type = CONNECT_TYPE_SERVER;

			cli_c->session = new_session;
			ser_c->session = new_session;

			cli_re = &cli_c->read;
			cli_re->data = cli_c;
			cli_we = &cli_c->write;
			cli_we->data = cli_c;
			ser_re = &ser_c->read;
			ser_re->data = ser_c;
			ser_we = &ser_c->write;
			ser_we->data = ser_c;

			/* set cli sockpt */
			sb_set_nonblocking(new_fd);
			sb_set_reuseaddr(new_fd, 1);
			sb_set_tcpkeepalive(new_fd);

			/* get client address info */
			cli_c->sockfd = new_fd;
			memcpy(&cli_c->net_address.sockaddr, &new_addr, new_addr_len);
			strcpy(cli_c->net_address.ip, inet_ntoa(new_addr.sin_addr));
			cli_c->net_address.port = ntohs(new_addr.sin_port );

			InfoOutput("listen ip[%s]-port[%d] accept connect ip[%s]-port[%d]", li->listen_address.ip, li->listen_address.port,
					cli_c->net_address.ip, cli_c->net_address.port);

			sb_add_read_event(cli_re, sb_proxy_get_new_request_event );
		}
	}

	return SB_OK;
}


#define SB_DNS_WAITING_HASH_SLOTS	11

static struct hlist_head hash_slots[SB_DNS_WAITING_HASH_SLOTS];
static struct list_head  wait_parse_list_head;
static struct list_head  parsing_list_head;
static struct ares_options options;

static unsigned long RSHash(const char *str)
{
	unsigned long a = 63689;
	unsigned long b = 378551;
	unsigned long hash = 0;
	while(*str) {
		hash = hash * a + (*str++);
		a *= b;
	}
	return hash;
}

int sb_proxy_dns_init()
{
	int i;

	for (i = 0; i < SB_DNS_HASH_SLOTS; i++) {
		INIT_HLIST_HEAD(&hash_slots[i]);
	}
	INIT_LIST_HEAD(&parsing_list_head);

	options.timeout = SB_DNS_TIMEOUT_TIME;
	options.tries = 2;

	return SB_OK;
}

/* flag == 1: force dns server update host */
int sb_proxy_dns_request(struct sb_cycle_env *env, struct sb_session *sess, int force_update)
{
	struct dns_msg msg;
	int host_len;
	int rc = 0;
	char *host;
	struct sb_dns_request *new_request;
	unsigned long hash_val;
	int slot_index;
	struct hlist_head *hash_head;

	host = sess->host;
	slot_index = RSHash(host) % SB_DNS_HASH_SLOTS;
	hash_head = &hash_slots[slot_index]; 
	if (hash_head->first == NULL) {
		new_request = (struct sb_dns_request*)calloc(1, sizeof(struct sb_dns_request));
		if (new_request == NULL) {
			ErrorOutput("malloc new sb_dns_request failed\n");
			return SB_ERROR;
		}

		strcpy(new_request->host, host);

		INIT_LIST_HEAD(&new_request->sess_list_head);

		hlist_add_head(&new_request->hash_node, hash_head);
		list_add(&sess->dns_list_node, &new_request->sess_list_head);
		
	} else {
		struct hlist_node *pos = NULL;
		struct hlist_node *pre_pos = NULL;
		struct sb_dns_request *type;
		int cmp;
		int ip_len;
		int add_last = 1;

		hlist_for_each_entry(type, pos, hash_head, hash_node) {
			if ((cmp = strcmp(type->host, host)) == 0) {
				list_add(&sess->dns_list_node, &type->sess_list_head);
				add_last = 0;
				break;

			} else if (cmp > 0) {
				new_request = (struct sb_dns_request*)calloc(1, sizeof(struct sb_dns_request));
				if (new_request == NULL) {
					ErrorOutput("malloc new sb_dns_request failed\n");
					return SB_ERROR;
				}
				strcpy(new_request->host, host);

				hlist_add_before(&new_request->hash_node, pos);
				INIT_LIST_HEAD(&new_request->sess_list_head);
				list_add(&sess->dns_list_node, &new_request->sess_list_head);
				add_last = 0;
				break;

			} else {
				pre_pos = pos;
			}
		}

		if (add_last) {
			new_request = (struct sb_dns_request*)calloc(1, sizeof(struct sb_dns_request));
			if (new_request == NULL) {
				ErrorOutput("malloc new sb_dns_request failed\n");
				return SB_ERROR;
			}
			strcpy(new_request->host, host);

			INIT_LIST_HEAD(&new_request->sess_list_head);
			list_add(&sess->dns_list_node, &new_request->sess_list_head);
			hlist_add_after(pre_pos, &new_request->hash_node);
		}
	}

	msg.m.mtype = env->workerno;
	host_len = strlen(host); 

	memcpy(msg.m.mtext, host, host_len);
	msg.mtext_len = host_len;
	if (force_update == 1) {	/* force flag */
		memcpy(msg.m.mtext, "#1", 2);
		msg.mtext_len = 2;
	} 

	rc = msg_send (env->msgqueueid, &msg, SB_NO_WAIT);
msg.m.mtext[msg.mtext_len] = '\0';
ErrorOutput("msgqueueid[%d], msg.m.mtext[%s], type[%ld], len[%d]", env->msgqueueid, msg.m.mtext, msg.m.mtype, msg.mtext_len);
	if (rc)
	{
		ErrorOutput ("send dns_msg failed, info[%s], errno[%d]-error[%s]", msg.m.mtext, errno, strerror(errno));
		list_del_init(&sess->dns_list_node);

		return SB_ERROR;
	} 
msg.m.mtext[msg.mtext_len] = '\0';
DebugOutput("dns_msg[%s]", msg.m.mtext);				

	return SB_OK;
}

int sb_proxy_dns_recv_resp(struct sb_cycle_env *env)
{
	int rc;
	struct dns_msg msg;
	int ip_len;
	struct sb_session *sess, *next_sess;
	char *host, *ip, status;
	char *resp_text;
	int slot_index;
	struct hlist_head *hash_head;

	while (1) {
		memset(&msg, 0x00, sizeof(struct dns_msg));
		rc = msg_recv(env->msgqueueid , env->workerno + SB_REQREPMSG_TYPESPLIT, &msg, IPC_NOWAIT);
		if (rc) {
			if (errno != EAGAIN && errno != ENOMSG) {
				ErrorOutput ("recv dns_msg errno[%d]-error[%s] [%d]", errno, strerror(errno), env->msgqueueid);
				return SB_ERROR;

			} else {
				//DebugOutput("no recv dns_msg");				
				break;
			}
		}

		resp_text = msg.m.mtext;	
		resp_text[msg.mtext_len] = '\0';

DebugOutput("RECV dns_msg[%s]-len[%d]", resp_text, msg.mtext_len);
		host = index(resp_text, '#');
		if (host == NULL) {
			status = SB_DNS_STATUS_ERROR;
			ip_len = 0;
		}
		else {
			*host = '\0';
			status = *(host + 1);
			ip = host + 3;
			ip_len = resp_text + msg.mtext_len - ip + 1;
		}

		host = resp_text;
		slot_index = RSHash(host) % SB_DNS_HASH_SLOTS;
		hash_head = &hash_slots[slot_index];
		if (hash_head->first == NULL) {
			/* no hash value */
			return;
		} else {
			struct hlist_node *pos = NULL;
			struct hlist_node *pre_pos = NULL;
			struct sb_dns_request *type;
			int cmp;

			/* can't find do nothing */
			hlist_for_each_entry(type, pos, hash_head, hash_node) {
				if ((cmp = strcmp(type->host, host)) == 0) {
					list_for_each_entry_safe (sess, next_sess, &type->sess_list_head, dns_list_node) {
						if (status == SB_DNS_STATUS_CHAR_OK) {	
							memcpy(sess->server.net_address.ip, ip, ip_len);
							sess->status = SB_DNS_STATUS_OK;

						} else if (status == SB_DNS_STATUS_CHAR_FAIL || status == SB_DNS_STATUS_CHAR_TIMEOUT) {
							sess->status = SB_DNS_STATUS_ERROR;
						} else {
							ErrorOutput("host[%s] dns request get unknown status [%c]", host, status);
							sess->status = SB_DNS_STATUS_ERROR;
						}

						sb_dns_done_handler(env, sess);
						list_del_init(&sess->dns_list_node);
					}	

				} else if (cmp > 0) {
					break;
				}
			}

		}

	}

	return SB_OK;
}

int sb_proxy_discard_resp(struct sb_cycle_env *env, int msgtype)
{
	struct dns_msg msg;
	int rc;

	while (1) {
		memset(&msg, 0x00, sizeof(struct dns_msg));
		rc = msg_recv(env->msgqueueid , msgtype + SB_REQREPMSG_TYPESPLIT, &msg, IPC_NOWAIT);
		if (rc) {
			if (errno != EAGAIN && errno != ENOMSG) {
				ErrorOutput ("recv dns_msg errno[%d]-error[%s] [%d]", errno, strerror(errno), env->msgqueueid);
				return SB_ERROR;
			}
		} else {
			break;
		}
	}

	return SB_OK;
}