text: #include "buffer.h"
  #include "server.h"
  #include "keyvalue.h"
  #include "log.h"
  
  #include "http_chunk.h"
  #include "fdevent.h"
  #include "connections.h"
  #include "response.h"
  #include "joblist.h"
  
  #include "plugin.h"
  
  #include "inet_ntop_cache.h"
  #include "crc32.h"
  
  #include <sys/types.h>
  
  #include <unistd.h>
  #include <errno.h>
  #include <fcntl.h>
  #include <string.h>
  #include <stdlib.h>
  #include <ctype.h>
  #include <assert.h>
  
  #include <stdio.h>
  
  #ifdef HAVE_SYS_FILIO_H
  # include <sys/filio.h>
  #endif
  
  #include "sys-socket.h"
  
  #define data_proxy data_fastcgi
  #define data_proxy_init data_fastcgi_init
  
  #define PROXY_RETRY_TIMEOUT 60
  
  /**
   *
   * the proxy module is based on the fastcgi module
   *
   * 28.06.2004 Jan Kneschke     The first release
   * 01.07.2004 Evgeny Rodichev  Several bugfixes and cleanups
   *            - co-ordinate up- and downstream flows correctly (proxy_demux_response
   *              and proxy_handle_fdevent)
   *            - correctly transfer upstream http_response_status;
   *            - some unused structures removed.
   *
   * TODO:      - delay upstream read if write_queue is too large
   *              (to prevent memory eating, like in apache). Shoud be
   *              configurable).
   *            - persistent connection with upstream servers
   *            - HTTP/1.1
   */
  typedef enum {
  	PROXY_BALANCE_UNSET,
  	PROXY_BALANCE_FAIR,
  	PROXY_BALANCE_HASH,
  	PROXY_BALANCE_RR
  } proxy_balance_t;
  
  typedef struct {
  	array *extensions;
  	unsigned short debug;
  
  	proxy_balance_t balance;
  } plugin_config;
  
  typedef struct {
  	PLUGIN_DATA;
  
  	buffer *parse_response;
  	buffer *balance_buf;
  
  	plugin_config **config_storage;
  
  	plugin_config conf;
  } plugin_data;
  
  typedef enum {
  	PROXY_STATE_INIT,
  	PROXY_STATE_CONNECT,
  	PROXY_STATE_PREPARE_WRITE,
  	PROXY_STATE_WRITE,
  	PROXY_STATE_READ,
  	PROXY_STATE_ERROR
  } proxy_connection_state_t;
  
  enum { PROXY_STDOUT, PROXY_END_REQUEST };
  
  typedef struct {
  	proxy_connection_state_t state;
  	time_t state_timestamp;
  
  	data_proxy *host;
  
  	buffer *response;
  	buffer *response_header;
  
  	chunkqueue *wb;
  
  	int fd; /* fd to the proxy process */
  	int fde_ndx; /* index into the fd-event buffer */
  
  	size_t path_info_offset; /* start of path_info in uri.path */
  
  	connection *remote_conn;  /* dump pointer */
  	plugin_data *plugin_data; /* dump pointer */
  } handler_ctx;
  
  
  /* ok, we need a prototype */
  static handler_t proxy_handle_fdevent(server *srv, void *ctx, int revents);
  
  static handler_ctx * handler_ctx_init(void) {
  	handler_ctx * hctx;
  
  
  	hctx = calloc(1, sizeof(*hctx));
  
  	hctx->state = PROXY_STATE_INIT;
  	hctx->host = NULL;
  
  	hctx->response = buffer_init();
  	hctx->response_header = buffer_init();
  
  	hctx->wb = chunkqueue_init();
  
  	hctx->fd = -1;
  	hctx->fde_ndx = -1;
  
  	return hctx;
  }
  
  static void handler_ctx_free(handler_ctx *hctx) {
  	buffer_free(hctx->response);
  	buffer_free(hctx->response_header);
  	chunkqueue_free(hctx->wb);
  
  	free(hctx);
  }
  
  INIT_FUNC(mod_proxy_init) {
  	plugin_data *p;
  
  	p = calloc(1, sizeof(*p));
  
  	p->parse_response = buffer_init();
  	p->balance_buf = buffer_init();
  
  	return p;
  }
  
  
  FREE_FUNC(mod_proxy_free) {
  	plugin_data *p = p_d;
  
  	UNUSED(srv);
  
  	buffer_free(p->parse_response);
  	buffer_free(p->balance_buf);
  
  	if (p->config_storage) {
  		size_t i;
  		for (i = 0; i < srv->config_context->used; i++) {
  			plugin_config *s = p->config_storage[i];
  
  			if (NULL == s) continue;
  
  			array_free(s->extensions);
  
  			free(s);
  		}
  		free(p->config_storage);
  	}
  
  	free(p);
  
  	return HANDLER_GO_ON;
  }
  
  SETDEFAULTS_FUNC(mod_proxy_set_defaults) {
  	plugin_data *p = p_d;
  	data_unset *du;
  	size_t i = 0;
  
  	config_values_t cv[] = {
  		{ "proxy.server",              NULL, T_CONFIG_LOCAL, T_CONFIG_SCOPE_CONNECTION },       /* 0 */
  		{ "proxy.debug",               NULL, T_CONFIG_SHORT, T_CONFIG_SCOPE_CONNECTION },       /* 1 */
  		{ "proxy.balance",             NULL, T_CONFIG_STRING, T_CONFIG_SCOPE_CONNECTION },      /* 2 */
  		{ NULL,                        NULL, T_CONFIG_UNSET, T_CONFIG_SCOPE_UNSET }
  	};
  
  	p->config_storage = calloc(1, srv->config_context->used * sizeof(plugin_config *));
  
  	for (i = 0; i < srv->config_context->used; i++) {
  		plugin_config *s;
  		array *ca;
  
  		s = malloc(sizeof(plugin_config));
  		s->extensions    = array_init();
  		s->debug         = 0;
  
  		cv[0].destination = s->extensions;
  		cv[1].destination = &(s->debug);
  		cv[2].destination = p->balance_buf;
  
  		buffer_reset(p->balance_buf);
  
  		p->config_storage[i] = s;
  		ca = ((data_config *)srv->config_context->data[i])->value;
  
  		if (0 != config_insert_values_global(srv, ca, cv)) {
  			return HANDLER_ERROR;
  		}
  
  		if (buffer_string_is_empty(p->balance_buf)) {
  			s->balance = PROXY_BALANCE_FAIR;
  		} else if (buffer_is_equal_string(p->balance_buf, CONST_STR_LEN("fair"))) {
  			s->balance = PROXY_BALANCE_FAIR;
  		} else if (buffer_is_equal_string(p->balance_buf, CONST_STR_LEN("round-robin"))) {
  			s->balance = PROXY_BALANCE_RR;
  		} else if (buffer_is_equal_string(p->balance_buf, CONST_STR_LEN("hash"))) {
  			s->balance = PROXY_BALANCE_HASH;
  		} else {
  			log_error_write(srv, __FILE__, __LINE__, "sb",
  				        "proxy.balance has to be one of: fair, round-robin, hash, but not:", p->balance_buf);
  			return HANDLER_ERROR;
  		}
  
  		if (NULL != (du = array_get_element(ca, "proxy.server"))) {
  			size_t j;
  			data_array *da = (data_array *)du;
  
  			if (du->type != TYPE_ARRAY) {
  				log_error_write(srv, __FILE__, __LINE__, "sss",
  						"unexpected type for key: ", "proxy.server", "array of strings");
  
  				return HANDLER_ERROR;
  			}
  
  			/*
  			 * proxy.server = ( "<ext>" => ...,
  			 *                  "<ext>" => ... )
  			 */
  
  			for (j = 0; j < da->value->used; j++) {
  				data_array *da_ext = (data_array *)da->value->data[j];
  				size_t n;
  
  				if (da_ext->type != TYPE_ARRAY) {
  					log_error_write(srv, __FILE__, __LINE__, "sssbs",
  							"unexpected type for key: ", "proxy.server",
  							"[", da->value->data[j]->key, "](string)");
  
  					return HANDLER_ERROR;
  				}
  
  				/*
  				 * proxy.server = ( "<ext>" =>
  				 *                     ( "<host>" => ( ... ),
  				 *                       "<host>" => ( ... )
  				 *                     ),
  				 *                    "<ext>" => ... )
  				 */
  
  				for (n = 0; n < da_ext->value->used; n++) {
  					data_array *da_host = (data_array *)da_ext->value->data[n];
  
  					data_proxy *df;
  					data_array *dfa;
  
  					config_values_t pcv[] = {
  						{ "host",              NULL, T_CONFIG_STRING, T_CONFIG_SCOPE_CONNECTION },      /* 0 */
  						{ "port",              NULL, T_CONFIG_SHORT, T_CONFIG_SCOPE_CONNECTION },       /* 1 */
  						{ NULL,                NULL, T_CONFIG_UNSET, T_CONFIG_SCOPE_UNSET }
  					};
  
  					if (da_host->type != TYPE_ARRAY) {
  						log_error_write(srv, __FILE__, __LINE__, "ssSBS",
  								"unexpected type for key:",
  								"proxy.server",
  								"[", da_ext->value->data[n]->key, "](string)");
  
  						return HANDLER_ERROR;
  					}
  
  					df = data_proxy_init();
  
  					df->port = 80;
  
  					buffer_copy_buffer(df->key, da_host->key);
  
  					pcv[0].destination = df->host;
  					pcv[1].destination = &(df->port);
  
  					if (0 != config_insert_values_internal(srv, da_host->value, pcv)) {
  						df->free((data_unset*) df);
  						return HANDLER_ERROR;
  					}
  
  					if (buffer_string_is_empty(df->host)) {
  						log_error_write(srv, __FILE__, __LINE__, "sbbbs",
  								"missing key (string):",
  								da->key,
  								da_ext->key,
  								da_host->key,
  								"host");
  
  						df->free((data_unset*) df);
  						return HANDLER_ERROR;
  					}
  
  					/* if extension already exists, take it */
  
  					if (NULL == (dfa = (data_array *)array_get_element(s->extensions, da_ext->key->ptr))) {
  						dfa = data_array_init();
  
  						buffer_copy_buffer(dfa->key, da_ext->key);
  
  						array_insert_unique(dfa->value, (data_unset *)df);
  						array_insert_unique(s->extensions, (data_unset *)dfa);
  					} else {
  						array_insert_unique(dfa->value, (data_unset *)df);
  					}
  				}
  			}
  		}
  	}
  
  	return HANDLER_GO_ON;
  }
  
  static void proxy_connection_close(server *srv, handler_ctx *hctx) {
  	plugin_data *p;
  	connection *con;
  
  	if (NULL == hctx) return;
  
  	p    = hctx->plugin_data;
  	con  = hctx->remote_conn;
  
  	if (hctx->fd != -1) {
  		fdevent_event_del(srv->ev, &(hctx->fde_ndx), hctx->fd);
  		fdevent_unregister(srv->ev, hctx->fd);
  
  		close(hctx->fd);
  		srv->cur_fds--;
  	}
  
  	if (hctx->host) {
  		hctx->host->usage--;
  	}
  
  	handler_ctx_free(hctx);
  	con->plugin_ctx[p->id] = NULL;
  }
  
  static int proxy_establish_connection(server *srv, handler_ctx *hctx) {
  	struct sockaddr *proxy_addr;
  	struct sockaddr_in proxy_addr_in;
  #if defined(HAVE_IPV6) && defined(HAVE_INET_PTON)
  	struct sockaddr_in6 proxy_addr_in6;
  #endif
  	socklen_t servlen;
  
  	plugin_data *p    = hctx->plugin_data;
  	data_proxy *host= hctx->host;
  	int proxy_fd       = hctx->fd;
  
  
  #if defined(HAVE_IPV6) && defined(HAVE_INET_PTON)
  	if (strstr(host->host->ptr, ":")) {
  		memset(&proxy_addr_in6, 0, sizeof(proxy_addr_in6));
  		proxy_addr_in6.sin6_family = AF_INET6;
  		inet_pton(AF_INET6, host->host->ptr, (char *) &proxy_addr_in6.sin6_addr);
  		proxy_addr_in6.sin6_port = htons(host->port);
  		servlen = sizeof(proxy_addr_in6);
  		proxy_addr = (struct sockaddr *) &proxy_addr_in6;
  	} else
  #endif
  	{
  		memset(&proxy_addr_in, 0, sizeof(proxy_addr_in));
  		proxy_addr_in.sin_family = AF_INET;
  		proxy_addr_in.sin_addr.s_addr = inet_addr(host->host->ptr);
  		proxy_addr_in.sin_port = htons(host->port);
  		servlen = sizeof(proxy_addr_in);
  		proxy_addr = (struct sockaddr *) &proxy_addr_in;
  	}
  
  
  	if (-1 == connect(proxy_fd, proxy_addr, servlen)) {
  		if (errno == EINPROGRESS || errno == EALREADY) {
  			if (p->conf.debug) {
  				log_error_write(srv, __FILE__, __LINE__, "sd",
  						"connect delayed:", proxy_fd);
  			}
  
  			return 1;
  		} else {
  
  			log_error_write(srv, __FILE__, __LINE__, "sdsd",
  					"connect failed:", proxy_fd, strerror(errno), errno);
  
  			return -1;
  		}
  	}
  	if (p->conf.debug) {
  		log_error_write(srv, __FILE__, __LINE__, "sd",
  				"connect succeeded: ", proxy_fd);
  	}
  
  	return 0;
  }
  
  static void proxy_set_header(connection *con, const char *key, const char *value) {
      data_string *ds_dst;
  
      if (NULL == (ds_dst = (data_string *)array_get_unused_element(con->request.headers, TYPE_STRING))) {
            ds_dst = data_string_init();
      }
  
      buffer_copy_string(ds_dst->key, key);
      buffer_copy_string(ds_dst->value, value);
      array_insert_unique(con->request.headers, (data_unset *)ds_dst);
  }
  
  static void proxy_append_header(connection *con, const char *key, const char *value) {
      data_string *ds_dst;
  
      if (NULL == (ds_dst = (data_string *)array_get_unused_element(con->request.headers, TYPE_STRING))) {
            ds_dst = data_string_init();
      }
  
      buffer_copy_string(ds_dst->key, key);
      buffer_append_string(ds_dst->value, value);
      array_insert_unique(con->request.headers, (data_unset *)ds_dst);
  }
  
  
  static int proxy_create_env(server *srv, handler_ctx *hctx) {
  	size_t i;
  
  	connection *con   = hctx->remote_conn;
  	buffer *b;
  
  	/* build header */
  
  	b = buffer_init();
  
  	/* request line */
  	buffer_copy_string(b, get_http_method_name(con->request.http_method));
  	buffer_append_string_len(b, CONST_STR_LEN(" "));
  
  	buffer_append_string_buffer(b, con->request.uri);
  	buffer_append_string_len(b, CONST_STR_LEN(" HTTP/1.0\r\n"));
  
  	proxy_append_header(con, "X-Forwarded-For", (char *)inet_ntop_cache_get_ip(srv, &(con->dst_addr)));
  	/* http_host is NOT is just a pointer to a buffer
  	 * which is NULL if it is not set */
  	if (!buffer_string_is_empty(con->request.http_host)) {
  		proxy_set_header(con, "X-Host", con->request.http_host->ptr);
  	}
  	proxy_set_header(con, "X-Forwarded-Proto", con->uri.scheme->ptr);
  
  	/* request header */
  	for (i = 0; i < con->request.headers->used; i++) {
  		data_string *ds;
  
  		ds = (data_string *)con->request.headers->data[i];
  
  		if (!buffer_is_empty(ds->value) && !buffer_is_empty(ds->key)) {
  			if (buffer_is_equal_string(ds->key, CONST_STR_LEN("Connection"))) continue;
  			if (buffer_is_equal_string(ds->key, CONST_STR_LEN("Proxy-Connection"))) continue;
  
  			buffer_append_string_buffer(b, ds->key);
  			buffer_append_string_len(b, CONST_STR_LEN(": "));
  			buffer_append_string_buffer(b, ds->value);
  			buffer_append_string_len(b, CONST_STR_LEN("\r\n"));
  		}
  	}
  
  	buffer_append_string_len(b, CONST_STR_LEN("\r\n"));
  
  	hctx->wb->bytes_in += buffer_string_length(b);
  	chunkqueue_append_buffer(hctx->wb, b);
  	buffer_free(b);
  
  	/* body */
  
  	if (con->request.content_length) {
  		chunkqueue *req_cq = con->request_content_queue;
  
  		chunkqueue_steal(hctx->wb, req_cq, req_cq->bytes_in);
  	}
  
  	return 0;
  }
  
  static int proxy_set_state(server *srv, handler_ctx *hctx, proxy_connection_state_t state) {
  	hctx->state = state;
  	hctx->state_timestamp = srv->cur_ts;
  
  	return 0;
  }
  
  
  static int proxy_response_parse(server *srv, connection *con, plugin_data *p, buffer *in) {
  	char *s, *ns;
  	int http_response_status = -1;
  
  	UNUSED(srv);
  
  	/* \r\n -> \0\0 */
  
  	buffer_copy_buffer(p->parse_response, in);
  
  	for (s = p->parse_response->ptr; NULL != (ns = strstr(s, "\r\n")); s = ns + 2) {
  		char *key, *value;
  		int key_len;
  		data_string *ds;
  		int copy_header;
  
  		ns[0] = '\0';
  		ns[1] = '\0';
  
  		if (-1 == http_response_status) {
  			/* The first line of a Response message is the Status-Line */
  
  			for (key=s; *key && *key != ' '; key++);
  
  			if (*key) {
  				http_response_status = (int) strtol(key, NULL, 10);
  				if (http_response_status <= 0) http_response_status = 502;
  			} else {
  				http_response_status = 502;
  			}
  
  			con->http_status = http_response_status;
  			con->parsed_response |= HTTP_STATUS;
  			continue;
  		}
  
  		if (NULL == (value = strchr(s, ':'))) {
  			/* now we expect: "<key>: <value>\n" */
  
  			continue;
  		}
  
  		key = s;
  		key_len = value - key;
  
  		value++;
  		/* strip WS */
  		while (*value == ' ' || *value == '\t') value++;
  
  		copy_header = 1;
  
  		switch(key_len) {
  		case 4:
  			if (0 == strncasecmp(key, "Date", key_len)) {
  				con->parsed_response |= HTTP_DATE;
  			}
  			break;
  		case 8:
  			if (0 == strncasecmp(key, "Location", key_len)) {
  				con->parsed_response |= HTTP_LOCATION;
  			}
  			break;
  		case 10:
  			if (0 == strncasecmp(key, "Connection", key_len)) {
  				copy_header = 0;
  			}
  			break;
  		case 14:
  			if (0 == strncasecmp(key, "Content-Length", key_len)) {
  				con->response.content_length = strtol(value, NULL, 10);
  				con->parsed_response |= HTTP_CONTENT_LENGTH;
  			}
  			break;
  		default:
  			break;
  		}
  
  		if (copy_header) {
  			if (NULL == (ds = (data_string *)array_get_unused_element(con->response.headers, TYPE_STRING))) {
  				ds = data_response_init();
  			}
  			buffer_copy_string_len(ds->key, key, key_len);
  			buffer_copy_string(ds->value, value);
  
  			array_insert_unique(con->response.headers, (data_unset *)ds);
  		}
  	}
  
  	return 0;
  }
  
  
  static int proxy_demux_response(server *srv, handler_ctx *hctx) {
  	int fin = 0;
  	int b;
  	ssize_t r;
  
  	plugin_data *p    = hctx->plugin_data;
  	connection *con   = hctx->remote_conn;
  	int proxy_fd       = hctx->fd;
  
  	/* check how much we have to read */
  	if (ioctl(hctx->fd, FIONREAD, &b)) {
  		log_error_write(srv, __FILE__, __LINE__, "sd",
  				"ioctl failed: ",
  				proxy_fd);
  		return -1;
  	}
  
  
  	if (p->conf.debug) {
  		log_error_write(srv, __FILE__, __LINE__, "sd",
  				"proxy - have to read:", b);
  	}
  
  	if (b > 0) {
  		buffer_string_prepare_append(hctx->response, b);
  
  		if (-1 == (r = read(hctx->fd, hctx->response->ptr + buffer_string_length(hctx->response), buffer_string_space(hctx->response)))) {
  			if (errno == EAGAIN) return 0;
  			log_error_write(srv, __FILE__, __LINE__, "sds",
  					"unexpected end-of-file (perhaps the proxy process died):",
  					proxy_fd, strerror(errno));
  			return -1;
  		}
  
  		/* this should be catched by the b > 0 above */
  		force_assert(r);
  
  		buffer_commit(hctx->response, r);
  
  #if 0
  		log_error_write(srv, __FILE__, __LINE__, "sdsbs",
  				"demux: Response buffer len", hctx->response->used, ":", hctx->response, ":");
  #endif
  
  		if (0 == con->got_response) {
  			con->got_response = 1;
  			buffer_string_prepare_copy(hctx->response_header, 1023);
  		}
  
  		if (0 == con->file_started) {
  			char *c;
  
  			/* search for the \r\n\r\n in the string */
  			if (NULL != (c = buffer_search_string_len(hctx->response, CONST_STR_LEN("\r\n\r\n")))) {
  				size_t hlen = c - hctx->response->ptr + 4;
  				size_t blen = buffer_string_length(hctx->response) - hlen;
  				/* found */
  
  				buffer_append_string_len(hctx->response_header, hctx->response->ptr, hlen);
  #if 0
  				log_error_write(srv, __FILE__, __LINE__, "sb", "Header:", hctx->response_header);
  #endif
  				/* parse the response header */
  				proxy_response_parse(srv, con, p, hctx->response_header);
  
  				/* enable chunked-transfer-encoding */
  				if (con->request.http_version == HTTP_VERSION_1_1 &&
  				    !(con->parsed_response & HTTP_CONTENT_LENGTH)) {
  					con->response.transfer_encoding = HTTP_TRANSFER_ENCODING_CHUNKED;
  				}
  
  				con->file_started = 1;
  				if (blen > 0) http_chunk_append_mem(srv, con, c + 4, blen);
  				buffer_reset(hctx->response);
  				joblist_append(srv, con);
  			}
  		} else {
  			http_chunk_append_buffer(srv, con, hctx->response);
  			joblist_append(srv, con);
  			buffer_reset(hctx->response);
  		}
  
  	} else {
  		/* reading from upstream done */
  		con->file_finished = 1;
  
  		http_chunk_close(srv, con);
  		joblist_append(srv, con);
  
  		fin = 1;
  	}
  
  	return fin;
  }
  
  
  static handler_t proxy_write_request(server *srv, handler_ctx *hctx) {
  	data_proxy *host= hctx->host;
  	connection *con   = hctx->remote_conn;
  
  	int ret;
  
  	if (!host || buffer_string_is_empty(host->host) || !host->port) return -1;
  
  	switch(hctx->state) {
  	case PROXY_STATE_CONNECT:
  		/* wait for the connect() to finish */
  
  		/* connect failed ? */
  		if (-1 == hctx->fde_ndx) return HANDLER_ERROR;
  
  		/* wait */
  		return HANDLER_WAIT_FOR_EVENT;
  
  		break;
  
  	case PROXY_STATE_INIT:
  #if defined(HAVE_IPV6) && defined(HAVE_INET_PTON)
  		if (strstr(host->host->ptr,":")) {
  			if (-1 == (hctx->fd = socket(AF_INET6, SOCK_STREAM, 0))) {
  				log_error_write(srv, __FILE__, __LINE__, "ss", "socket failed: ", strerror(errno));
  				return HANDLER_ERROR;
  			}
  		} else
  #endif
  		{
  			if (-1 == (hctx->fd = socket(AF_INET, SOCK_STREAM, 0))) {
  				log_error_write(srv, __FILE__, __LINE__, "ss", "socket failed: ", strerror(errno));
  				return HANDLER_ERROR;
  			}
  		}
  		hctx->fde_ndx = -1;
  
  		srv->cur_fds++;
  
  		fdevent_register(srv->ev, hctx->fd, proxy_handle_fdevent, hctx);
  
  		if (-1 == fdevent_fcntl_set(srv->ev, hctx->fd)) {
  			log_error_write(srv, __FILE__, __LINE__, "ss", "fcntl failed: ", strerror(errno));
  
  			return HANDLER_ERROR;
  		}
  
  		switch (proxy_establish_connection(srv, hctx)) {
  		case 1:
  			proxy_set_state(srv, hctx, PROXY_STATE_CONNECT);
  
  			/* connection is in progress, wait for an event and call getsockopt() below */
  
  			fdevent_event_set(srv->ev, &(hctx->fde_ndx), hctx->fd, FDEVENT_OUT);
  
  			return HANDLER_WAIT_FOR_EVENT;
  		case -1:
  			/* if ECONNREFUSED choose another connection -> FIXME */
  			hctx->fde_ndx = -1;
  
  			return HANDLER_ERROR;
  		default:
  			/* everything is ok, go on */
  			proxy_set_state(srv, hctx, PROXY_STATE_PREPARE_WRITE);
  			break;
  		}
  
  		/* fall through */
  
  	case PROXY_STATE_PREPARE_WRITE:
  		proxy_create_env(srv, hctx);
  
  		proxy_set_state(srv, hctx, PROXY_STATE_WRITE);
  
  		/* fall through */
  	case PROXY_STATE_WRITE:;
  		ret = srv->network_backend_write(srv, con, hctx->fd, hctx->wb, MAX_WRITE_LIMIT);
  
  		chunkqueue_remove_finished_chunks(hctx->wb);
  
  		if (-1 == ret) { /* error on our side */
  			log_error_write(srv, __FILE__, __LINE__, "ssd", "write failed:", strerror(errno), errno);
  
  			return HANDLER_ERROR;
  		} else if (-2 == ret) { /* remote close */
  			log_error_write(srv, __FILE__, __LINE__, "ssd", "write failed, remote connection close:", strerror(errno), errno);
  
  			return HANDLER_ERROR;
  		}
  
  		if (hctx->wb->bytes_out == hctx->wb->bytes_in) {
  			proxy_set_state(srv, hctx, PROXY_STATE_READ);
  
  			fdevent_event_del(srv->ev, &(hctx->fde_ndx), hctx->fd);
  			fdevent_event_set(srv->ev, &(hctx->fde_ndx), hctx->fd, FDEVENT_IN);
  		} else {
  			fdevent_event_set(srv->ev, &(hctx->fde_ndx), hctx->fd, FDEVENT_OUT);
  
  			return HANDLER_WAIT_FOR_EVENT;
  		}
  
  		return HANDLER_WAIT_FOR_EVENT;
  	case PROXY_STATE_READ:
  		/* waiting for a response */
  		return HANDLER_WAIT_FOR_EVENT;
  	default:
  		log_error_write(srv, __FILE__, __LINE__, "s", "(debug) unknown state");
  		return HANDLER_ERROR;
  	}
  
  	return HANDLER_GO_ON;
  }
  
  #define PATCH(x) \
  	p->conf.x = s->x;
  static int mod_proxy_patch_connection(server *srv, connection *con, plugin_data *p) {
  	size_t i, j;
  	plugin_config *s = p->config_storage[0];
  
  	PATCH(extensions);
  	PATCH(debug);
  	PATCH(balance);
  
  	/* skip the first, the global context */
  	for (i = 1; i < srv->config_context->used; i++) {
  		data_config *dc = (data_config *)srv->config_context->data[i];
  		s = p->config_storage[i];
  
  		/* condition didn't match */
  		if (!config_check_cond(srv, con, dc)) continue;
  
  		/* merge config */
  		for (j = 0; j < dc->value->used; j++) {
  			data_unset *du = dc->value->data[j];
  
  			if (buffer_is_equal_string(du->key, CONST_STR_LEN("proxy.server"))) {
  				PATCH(extensions);
  			} else if (buffer_is_equal_string(du->key, CONST_STR_LEN("proxy.debug"))) {
  				PATCH(debug);
  			} else if (buffer_is_equal_string(du->key, CONST_STR_LEN("proxy.balance"))) {
  				PATCH(balance);
  			}
  		}
  	}
  
  	return 0;
  }
  #undef PATCH
  
  SUBREQUEST_FUNC(mod_proxy_handle_subrequest) {
  	plugin_data *p = p_d;
  
  	handler_ctx *hctx = con->plugin_ctx[p->id];
  	data_proxy *host;
  
  	if (NULL == hctx) return HANDLER_GO_ON;
  
  	mod_proxy_patch_connection(srv, con, p);
  
  	host = hctx->host;
  
  	/* not my job */
  	if (con->mode != p->id) return HANDLER_GO_ON;
  
  	/* ok, create the request */
  	switch(proxy_write_request(srv, hctx)) {
  	case HANDLER_ERROR:
  		log_error_write(srv, __FILE__, __LINE__,  "sbdd", "proxy-server disabled:",
  				host->host,
  				host->port,
  				hctx->fd);
  
  		/* disable this server */
  		host->is_disabled = 1;
  		host->disable_ts = srv->cur_ts;
  
  		proxy_connection_close(srv, hctx);
  
  		/* reset the enviroment and restart the sub-request */
  		buffer_reset(con->physical.path);
  		con->mode = DIRECT;
  
  		joblist_append(srv, con);
  
  		/* mis-using HANDLER_WAIT_FOR_FD to break out of the loop
  		 * and hope that the childs will be restarted
  		 *
  		 */
  
  		return HANDLER_WAIT_FOR_FD;
  	case HANDLER_WAIT_FOR_EVENT:
  		break;
  	case HANDLER_WAIT_FOR_FD:
  		return HANDLER_WAIT_FOR_FD;
  	default:
  		break;
  	}
  
  	if (con->file_started == 1) {
  		return HANDLER_FINISHED;
  	} else {
  		return HANDLER_WAIT_FOR_EVENT;
  	}
  }
  
  static handler_t proxy_handle_fdevent(server *srv, void *ctx, int revents) {
  	handler_ctx *hctx = ctx;
  	connection  *con  = hctx->remote_conn;
  	plugin_data *p    = hctx->plugin_data;
  
  
  	if ((revents & FDEVENT_IN) &&
  	    hctx->state == PROXY_STATE_READ) {
  
  		if (p->conf.debug) {
  			log_error_write(srv, __FILE__, __LINE__, "sd",
  					"proxy: fdevent-in", hctx->state);
  		}
  
  		switch (proxy_demux_response(srv, hctx)) {
  		case 0:
  			break;
  		case 1:
  			/* we are done */
  			proxy_connection_close(srv, hctx);
  			log_error_write(srv, __FILE__, __LINE__, "s", "proxy request finished");
  
  			joblist_append(srv, con);
  			return HANDLER_FINISHED;
  		case -1:
  			if (con->file_started == 0) {
  				/* nothing has been send out yet, send a 500 */
  				connection_set_state(srv, con, CON_STATE_HANDLE_REQUEST);
  				con->http_status = 500;
  				con->mode = DIRECT;
  			} else {
  				/* response might have been already started, kill the connection */
  				connection_set_state(srv, con, CON_STATE_ERROR);
  			}
  
  			joblist_append(srv, con);
  			return HANDLER_FINISHED;
  		}
  	}
  
  	if (revents & FDEVENT_OUT) {
  		if (p->conf.debug) {
  			log_error_write(srv, __FILE__, __LINE__, "sd",
  					"proxy: fdevent-out", hctx->state);
  		}
  
  		if (hctx->state == PROXY_STATE_CONNECT) {
  			int socket_error;
  			socklen_t socket_error_len = sizeof(socket_error);
  
  			/* we don't need it anymore */
  			fdevent_event_del(srv->ev, &(hctx->fde_ndx), hctx->fd);
  			hctx->fde_ndx = -1;
  
  			/* try to finish the connect() */
  			if (0 != getsockopt(hctx->fd, SOL_SOCKET, SO_ERROR, &socket_error, &socket_error_len)) {
  				log_error_write(srv, __FILE__, __LINE__, "ss",
  					"getsockopt failed:", strerror(errno));
  
  				joblist_append(srv, con);
  				return HANDLER_FINISHED;
  			}
  			if (socket_error != 0) {
  				log_error_write(srv, __FILE__, __LINE__, "ss",
  					"establishing connection failed:", strerror(socket_error),
  					"port:", hctx->host->port);
  
  				joblist_append(srv, con);
  				return HANDLER_FINISHED;
  			}
  			if (p->conf.debug) {
  				log_error_write(srv, __FILE__, __LINE__,  "s", "proxy - connect - delayed success");
  			}
  
  			proxy_set_state(srv, hctx, PROXY_STATE_PREPARE_WRITE);
  		}
  
  		if (hctx->state == PROXY_STATE_PREPARE_WRITE ||
  		    hctx->state == PROXY_STATE_WRITE) {
  			/* we are allowed to send something out
  			 *
  			 * 1. after a just finished connect() call
  			 * 2. in a unfinished write() call (long POST request)
  			 */
  			return mod_proxy_handle_subrequest(srv, con, p);
  		} else {
  			log_error_write(srv, __FILE__, __LINE__, "sd",
  					"proxy: out", hctx->state);
  		}
  	}
  
  	/* perhaps this issue is already handled */
  	if (revents & FDEVENT_HUP) {
  		if (p->conf.debug) {
  			log_error_write(srv, __FILE__, __LINE__, "sd",
  					"proxy: fdevent-hup", hctx->state);
  		}
  
  		if (hctx->state == PROXY_STATE_CONNECT) {
  			/* connect() -> EINPROGRESS -> HUP */
  
  			/**
  			 * what is proxy is doing if it can't reach the next hop ?
  			 *
  			 */
  
  			if (hctx->host) {
  				hctx->host->is_disabled = 1;
  				hctx->host->disable_ts = srv->cur_ts;
  				log_error_write(srv, __FILE__, __LINE__,  "sbdd", "proxy-server disabled:",
  						hctx->host->host,
  						hctx->host->port,
  						hctx->fd);
  
  				/* disable this server */
  				hctx->host->is_disabled = 1;
  				hctx->host->disable_ts = srv->cur_ts;
  
  				proxy_connection_close(srv, hctx);
  
  				/* reset the enviroment and restart the sub-request */
  				buffer_reset(con->physical.path);
  				con->mode = DIRECT;
  
  				joblist_append(srv, con);
  			} else {
  				proxy_connection_close(srv, hctx);
  				joblist_append(srv, con);
  
  				con->mode = DIRECT;
  				con->http_status = 503;
  			}
  
  			return HANDLER_FINISHED;
  		}
  
  		if (!con->file_finished) {
  			http_chunk_close(srv, con);
  		}
  
  		con->file_finished = 1;
  		proxy_connection_close(srv, hctx);
  		joblist_append(srv, con);
  	} else if (revents & FDEVENT_ERR) {
  		/* kill all connections to the proxy process */
  
  		log_error_write(srv, __FILE__, __LINE__, "sd", "proxy-FDEVENT_ERR, but no HUP", revents);
  
  		con->file_finished = 1;
  		joblist_append(srv, con);
  		proxy_connection_close(srv, hctx);
  	}
  
  	return HANDLER_FINISHED;
  }
  
  static handler_t mod_proxy_check_extension(server *srv, connection *con, void *p_d) {
  	plugin_data *p = p_d;
  	size_t s_len;
  	unsigned long last_max = ULONG_MAX;
  	int max_usage = INT_MAX;
  	int ndx = -1;
  	size_t k;
  	buffer *fn;
  	data_array *extension = NULL;
  	size_t path_info_offset;
  
  	if (con->mode != DIRECT) return HANDLER_GO_ON;
  
  	/* Possibly, we processed already this request */
  	if (con->file_started == 1) return HANDLER_GO_ON;
  
  	mod_proxy_patch_connection(srv, con, p);
  
  	fn = con->uri.path;
  	if (buffer_string_is_empty(fn)) return HANDLER_ERROR;
  	s_len = buffer_string_length(fn);
  
  	path_info_offset = 0;
  
  	if (p->conf.debug) {
  		log_error_write(srv, __FILE__, __LINE__,  "s", "proxy - start");
  	}
  
  	/* check if extension matches */
  	for (k = 0; k < p->conf.extensions->used; k++) {
  		data_array *ext = NULL;
  		size_t ct_len;
  
  		ext = (data_array *)p->conf.extensions->data[k];
  
  		if (buffer_is_empty(ext->key)) continue;
  
  		ct_len = buffer_string_length(ext->key);
  
  		if (s_len < ct_len) continue;
  
  		/* check extension in the form "/proxy_pattern" */
  		if (*(ext->key->ptr) == '/') {
  			if (strncmp(fn->ptr, ext->key->ptr, ct_len) == 0) {
  				if (s_len > ct_len + 1) {
  					char *pi_offset;
  
  					if (NULL != (pi_offset = strchr(fn->ptr + ct_len + 1, '/'))) {
  						path_info_offset = pi_offset - fn->ptr;
  					}
  				}
  				extension = ext;
  				break;
  			}
  		} else if (0 == strncmp(fn->ptr + s_len - ct_len, ext->key->ptr, ct_len)) {
  			/* check extension in the form ".fcg" */
  			extension = ext;
  			break;
  		}
  	}
  
  	if (NULL == extension) {
  		return HANDLER_GO_ON;
  	}
  
  	if (p->conf.debug) {
  		log_error_write(srv, __FILE__, __LINE__,  "s", "proxy - ext found");
  	}
  
  	if (extension->value->used == 1) {
  		if ( ((data_proxy *)extension->value->data[0])->is_disabled ) {
  			ndx = -1;
  		} else {
  			ndx = 0;
  		}
  	} else if (extension->value->used != 0) switch(p->conf.balance) {
  	case PROXY_BALANCE_HASH:
  		/* hash balancing */
  
  		if (p->conf.debug) {
  			log_error_write(srv, __FILE__, __LINE__,  "sd",
  					"proxy - used hash balancing, hosts:", extension->value->used);
  		}
  
  		for (k = 0, ndx = -1, last_max = ULONG_MAX; k < extension->value->used; k++) {
  			data_proxy *host = (data_proxy *)extension->value->data[k];
  			unsigned long cur_max;
  
  			if (host->is_disabled) continue;
  
  			cur_max = generate_crc32c(CONST_BUF_LEN(con->uri.path)) +
  				generate_crc32c(CONST_BUF_LEN(host->host)) + /* we can cache this */
  				generate_crc32c(CONST_BUF_LEN(con->uri.authority));
  
  			if (p->conf.debug) {
  				log_error_write(srv, __FILE__, __LINE__,  "sbbbd",
  						"proxy - election:",
  						con->uri.path,
  						host->host,
  						con->uri.authority,
  						cur_max);
  			}
  
  			if ((last_max == ULONG_MAX) || /* first round */
  		   	    (cur_max > last_max)) {
  				last_max = cur_max;
  
  				ndx = k;
  			}
  		}
  
  		break;
  	case PROXY_BALANCE_FAIR:
  		/* fair balancing */
  		if (p->conf.debug) {
  			log_error_write(srv, __FILE__, __LINE__,  "s",
  					"proxy - used fair balancing");
  		}
  
  		for (k = 0, ndx = -1, max_usage = INT_MAX; k < extension->value->used; k++) {
  			data_proxy *host = (data_proxy *)extension->value->data[k];
  
  			if (host->is_disabled) continue;
  
  			if (host->usage < max_usage) {
  				max_usage = host->usage;
  
  				ndx = k;
  			}
  		}
  
  		break;
  	case PROXY_BALANCE_RR: {
  		data_proxy *host;
  
  		/* round robin */
  		if (p->conf.debug) {
  			log_error_write(srv, __FILE__, __LINE__,  "s",
  					"proxy - used round-robin balancing");
  		}
  
  		/* just to be sure */
  		force_assert(extension->value->used < INT_MAX);
  
  		host = (data_proxy *)extension->value->data[0];
  
  		/* Use last_used_ndx from first host in list */
  		k = host->last_used_ndx;
  		ndx = k + 1; /* use next host after the last one */
  		if (ndx < 0) ndx = 0;
  
  		/* Search first active host after last_used_ndx */
  		while ( ndx < (int) extension->value->used
  				&& (host = (data_proxy *)extension->value->data[ndx])->is_disabled ) ndx++;
  
  		if (ndx >= (int) extension->value->used) {
  			/* didn't found a higher id, wrap to the start */
  			for (ndx = 0; ndx <= (int) k; ndx++) {
  				host = (data_proxy *)extension->value->data[ndx];
  				if (!host->is_disabled) break;
  			}
  
  			/* No active host found */
  			if (host->is_disabled) ndx = -1;
  		}
  
  		/* Save new index for next round */
  		((data_proxy *)extension->value->data[0])->last_used_ndx = ndx;
  
  		break;
  	}
  	default:
  		break;
  	}
  
  	/* found a server */
  	if (ndx != -1) {
  		data_proxy *host = (data_proxy *)extension->value->data[ndx];
  
  		/*
  		 * if check-local is disabled, use the uri.path handler
  		 *
  		 */
  
  		/* init handler-context */
  		handler_ctx *hctx;
  		hctx = handler_ctx_init();
  
  		hctx->path_info_offset = path_info_offset;
  		hctx->remote_conn      = con;
  		hctx->plugin_data      = p;
  		hctx->host             = host;
  
  		con->plugin_ctx[p->id] = hctx;
  
  		host->usage++;
  
  		con->mode = p->id;
  
  		if (p->conf.debug) {
  			log_error_write(srv, __FILE__, __LINE__,  "sbd",
  					"proxy - found a host",
  					host->host, host->port);
  		}
  
  		return HANDLER_GO_ON;
  	} else {
  		/* no handler found */
  		con->http_status = 500;
  
  		log_error_write(srv, __FILE__, __LINE__,  "sb",
  				"no proxy-handler found for:",
  				fn);
  
  		return HANDLER_FINISHED;
  	}
  	return HANDLER_GO_ON;
  }
  
  static handler_t mod_proxy_connection_close_callback(server *srv, connection *con, void *p_d) {
  	plugin_data *p = p_d;
  
  	proxy_connection_close(srv, con->plugin_ctx[p->id]);
  
  	return HANDLER_GO_ON;
  }
  
  /**
   *
   * the trigger re-enables the disabled connections after the timeout is over
   *
   * */
  
  TRIGGER_FUNC(mod_proxy_trigger) {
  	plugin_data *p = p_d;
  
  	if (p->config_storage) {
  		size_t i, n, k;
  		for (i = 0; i < srv->config_context->used; i++) {
  			plugin_config *s = p->config_storage[i];
  
  			if (!s) continue;
  
  			/* get the extensions for all configs */
  
  			for (k = 0; k < s->extensions->used; k++) {
  				data_array *extension = (data_array *)s->extensions->data[k];
  
  				/* get all hosts */
  				for (n = 0; n < extension->value->used; n++) {
  					data_proxy *host = (data_proxy *)extension->value->data[n];
  
  					if (!host->is_disabled ||
  					    srv->cur_ts - host->disable_ts < 5) continue;
  
  					log_error_write(srv, __FILE__, __LINE__,  "sbd",
  							"proxy - re-enabled:",
  							host->host, host->port);
  
  					host->is_disabled = 0;
  				}
  			}
  		}
  	}
  
  	return HANDLER_GO_ON;
  }
  
  
  int mod_proxy_plugin_init(plugin *p);
  int mod_proxy_plugin_init(plugin *p) {
  	p->version      = LIGHTTPD_VERSION_ID;
  	p->name         = buffer_init_string("proxy");
  
  	p->init         = mod_proxy_init;
  	p->cleanup      = mod_proxy_free;
  	p->set_defaults = mod_proxy_set_defaults;
  	p->connection_reset        = mod_proxy_connection_close_callback; /* end of req-resp cycle */
  	p->handle_connection_close = mod_proxy_connection_close_callback; /* end of client connection */
  	p->handle_uri_clean        = mod_proxy_check_extension;
  	p->handle_subrequest       = mod_proxy_handle_subrequest;
  	p->handle_trigger          = mod_proxy_trigger;
  
  	p->data         = NULL;
  
  	return 0;
  }
  