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Linux Cross Reference
Nginx/http/ngx_http_upstream.c

Version: ~ [ nginx-0.6.26 ] ~ [ nginx-0.5.35 ] ~ [ nginx-0.5.20 ] ~ [ nginx-0.5.19 ] ~

  1 
  2 /*
  3  * Copyright (C) Igor Sysoev
  4  */
  5 
  6 
  7 #include <ngx_config.h>
  8 #include <ngx_core.h>
  9 #include <ngx_http.h>
 10 
 11 
 12 static void ngx_http_upstream_resolve_handler(ngx_resolver_ctx_t *ctx);
 13 static void ngx_http_upstream_rd_check_broken_connection(ngx_http_request_t *r);
 14 static void ngx_http_upstream_wr_check_broken_connection(ngx_http_request_t *r);
 15 static void ngx_http_upstream_check_broken_connection(ngx_http_request_t *r,
 16     ngx_event_t *ev);
 17 static void ngx_http_upstream_connect(ngx_http_request_t *r,
 18     ngx_http_upstream_t *u);
 19 static ngx_int_t ngx_http_upstream_reinit(ngx_http_request_t *r,
 20     ngx_http_upstream_t *u);
 21 static void ngx_http_upstream_send_request(ngx_http_request_t *r,
 22     ngx_http_upstream_t *u);
 23 static void ngx_http_upstream_send_request_handler(ngx_event_t *wev);
 24 static void ngx_http_upstream_process_header(ngx_event_t *rev);
 25 static ngx_int_t ngx_http_upstream_test_connect(ngx_connection_t *c);
 26 static void ngx_http_upstream_process_body_in_memory(ngx_event_t *rev);
 27 static void ngx_http_upstream_send_response(ngx_http_request_t *r,
 28     ngx_http_upstream_t *u);
 29 static void
 30     ngx_http_upstream_process_non_buffered_downstream(ngx_http_request_t *r);
 31 static void ngx_http_upstream_process_non_buffered_body(ngx_event_t *ev);
 32 static ngx_int_t ngx_http_upstream_non_buffered_filter_init(void *data);
 33 static ngx_int_t ngx_http_upstream_non_buffered_filter(void *data,
 34     ssize_t bytes);
 35 static void ngx_http_upstream_process_downstream(ngx_http_request_t *r);
 36 static void ngx_http_upstream_process_body(ngx_event_t *ev);
 37 static void ngx_http_upstream_store(ngx_http_request_t *r,
 38     ngx_http_upstream_t *u);
 39 static void ngx_http_upstream_dummy_handler(ngx_event_t *wev);
 40 static void ngx_http_upstream_next(ngx_http_request_t *r,
 41     ngx_http_upstream_t *u, ngx_uint_t ft_type);
 42 static void ngx_http_upstream_cleanup(void *data);
 43 static void ngx_http_upstream_finalize_request(ngx_http_request_t *r,
 44     ngx_http_upstream_t *u, ngx_int_t rc);
 45 
 46 static ngx_int_t ngx_http_upstream_process_header_line(ngx_http_request_t *r,
 47     ngx_table_elt_t *h, ngx_uint_t offset);
 48 static ngx_int_t
 49     ngx_http_upstream_process_multi_header_lines(ngx_http_request_t *r,
 50     ngx_table_elt_t *h, ngx_uint_t offset);
 51 static ngx_int_t ngx_http_upstream_ignore_header_line(ngx_http_request_t *r,
 52     ngx_table_elt_t *h, ngx_uint_t offset);
 53 static ngx_int_t ngx_http_upstream_process_limit_rate(ngx_http_request_t *r,
 54     ngx_table_elt_t *h, ngx_uint_t offset);
 55 static ngx_int_t ngx_http_upstream_process_buffering(ngx_http_request_t *r,
 56     ngx_table_elt_t *h, ngx_uint_t offset);
 57 static ngx_int_t ngx_http_upstream_process_charset(ngx_http_request_t *r,
 58     ngx_table_elt_t *h, ngx_uint_t offset);
 59 static ngx_int_t ngx_http_upstream_copy_header_line(ngx_http_request_t *r,
 60     ngx_table_elt_t *h, ngx_uint_t offset);
 61 static ngx_int_t
 62     ngx_http_upstream_copy_multi_header_lines(ngx_http_request_t *r,
 63     ngx_table_elt_t *h, ngx_uint_t offset);
 64 static ngx_int_t ngx_http_upstream_copy_content_type(ngx_http_request_t *r,
 65     ngx_table_elt_t *h, ngx_uint_t offset);
 66 static ngx_int_t ngx_http_upstream_copy_content_length(ngx_http_request_t *r,
 67     ngx_table_elt_t *h, ngx_uint_t offset);
 68 static ngx_int_t ngx_http_upstream_rewrite_location(ngx_http_request_t *r,
 69     ngx_table_elt_t *h, ngx_uint_t offset);
 70 static ngx_int_t ngx_http_upstream_rewrite_refresh(ngx_http_request_t *r,
 71     ngx_table_elt_t *h, ngx_uint_t offset);
 72 #if (NGX_HTTP_GZIP)
 73 static ngx_int_t ngx_http_upstream_copy_content_encoding(ngx_http_request_t *r,
 74     ngx_table_elt_t *h, ngx_uint_t offset);
 75 #endif
 76 
 77 static ngx_int_t ngx_http_upstream_add_variables(ngx_conf_t *cf);
 78 static ngx_int_t ngx_http_upstream_addr_variable(ngx_http_request_t *r,
 79     ngx_http_variable_value_t *v, uintptr_t data);
 80 static ngx_int_t ngx_http_upstream_status_variable(ngx_http_request_t *r,
 81     ngx_http_variable_value_t *v, uintptr_t data);
 82 static ngx_int_t ngx_http_upstream_response_time_variable(ngx_http_request_t *r,
 83     ngx_http_variable_value_t *v, uintptr_t data);
 84 
 85 static char *ngx_http_upstream(ngx_conf_t *cf, ngx_command_t *cmd, void *dummy);
 86 static char *ngx_http_upstream_server(ngx_conf_t *cf, ngx_command_t *cmd,
 87     void *conf);
 88 
 89 static void *ngx_http_upstream_create_main_conf(ngx_conf_t *cf);
 90 static char *ngx_http_upstream_init_main_conf(ngx_conf_t *cf, void *conf);
 91 
 92 #if (NGX_HTTP_SSL)
 93 static void ngx_http_upstream_ssl_init_connection(ngx_http_request_t *,
 94     ngx_http_upstream_t *u, ngx_connection_t *c);
 95 static void ngx_http_upstream_ssl_handshake(ngx_connection_t *c);
 96 #endif
 97 
 98 
 99 ngx_http_upstream_header_t  ngx_http_upstream_headers_in[] = {
100 
101     { ngx_string("Status"),
102                  ngx_http_upstream_process_header_line,
103                  offsetof(ngx_http_upstream_headers_in_t, status),
104                  ngx_http_upstream_copy_header_line, 0, 0 },
105 
106     { ngx_string("Content-Type"),
107                  ngx_http_upstream_process_header_line,
108                  offsetof(ngx_http_upstream_headers_in_t, content_type),
109                  ngx_http_upstream_copy_content_type, 0, 1 },
110 
111     { ngx_string("Content-Length"),
112                  ngx_http_upstream_process_header_line,
113                  offsetof(ngx_http_upstream_headers_in_t, content_length),
114                  ngx_http_upstream_copy_content_length, 0, 0 },
115 
116     { ngx_string("Date"),
117                  ngx_http_upstream_process_header_line,
118                  offsetof(ngx_http_upstream_headers_in_t, date),
119                  ngx_http_upstream_copy_header_line,
120                  offsetof(ngx_http_headers_out_t, date), 0 },
121 
122     { ngx_string("Last-Modified"),
123                  ngx_http_upstream_process_header_line,
124                  offsetof(ngx_http_upstream_headers_in_t, last_modified),
125                  ngx_http_upstream_copy_header_line,
126                  offsetof(ngx_http_headers_out_t, last_modified), 0 },
127 
128     { ngx_string("Server"),
129                  ngx_http_upstream_process_header_line,
130                  offsetof(ngx_http_upstream_headers_in_t, server),
131                  ngx_http_upstream_copy_header_line,
132                  offsetof(ngx_http_headers_out_t, server), 0 },
133 
134     { ngx_string("WWW-Authenticate"),
135                  ngx_http_upstream_process_header_line,
136                  offsetof(ngx_http_upstream_headers_in_t, www_authenticate),
137                  ngx_http_upstream_copy_header_line, 0, 0 },
138 
139     { ngx_string("Location"),
140                  ngx_http_upstream_ignore_header_line, 0,
141                  ngx_http_upstream_rewrite_location, 0, 0 },
142 
143     { ngx_string("Refresh"),
144                  ngx_http_upstream_ignore_header_line, 0,
145                  ngx_http_upstream_rewrite_refresh, 0, 0 },
146 
147     { ngx_string("Set-Cookie"),
148                  ngx_http_upstream_ignore_header_line, 0,
149                  ngx_http_upstream_copy_header_line, 0, 1 },
150 
151     { ngx_string("Content-Disposition"),
152                  ngx_http_upstream_ignore_header_line, 0,
153                  ngx_http_upstream_copy_header_line, 0, 1 },
154 
155     { ngx_string("Cache-Control"),
156                  ngx_http_upstream_process_multi_header_lines,
157                  offsetof(ngx_http_upstream_headers_in_t, cache_control),
158                  ngx_http_upstream_copy_multi_header_lines,
159                  offsetof(ngx_http_headers_out_t, cache_control), 1 },
160 
161     { ngx_string("Expires"),
162                  ngx_http_upstream_process_header_line,
163                  offsetof(ngx_http_upstream_headers_in_t, expires),
164                  ngx_http_upstream_copy_header_line,
165                  offsetof(ngx_http_headers_out_t, expires), 1 },
166 
167     { ngx_string("Accept-Ranges"),
168                  ngx_http_upstream_process_header_line,
169                  offsetof(ngx_http_upstream_headers_in_t, accept_ranges),
170                  ngx_http_upstream_copy_header_line,
171                  offsetof(ngx_http_headers_out_t, accept_ranges), 1 },
172 
173     { ngx_string("Connection"),
174                  ngx_http_upstream_ignore_header_line, 0,
175                  ngx_http_upstream_ignore_header_line, 0, 0 },
176 
177     { ngx_string("Keep-Alive"),
178                  ngx_http_upstream_ignore_header_line, 0,
179                  ngx_http_upstream_ignore_header_line, 0, 0 },
180 
181     { ngx_string("X-Powered-By"),
182                  ngx_http_upstream_ignore_header_line, 0,
183                  ngx_http_upstream_copy_header_line, 0, 0 },
184 
185     { ngx_string("X-Accel-Expires"),
186                  ngx_http_upstream_process_header_line,
187                  offsetof(ngx_http_upstream_headers_in_t, x_accel_expires),
188                  ngx_http_upstream_copy_header_line, 0, 0 },
189 
190     { ngx_string("X-Accel-Redirect"),
191                  ngx_http_upstream_process_header_line,
192                  offsetof(ngx_http_upstream_headers_in_t, x_accel_redirect),
193                  ngx_http_upstream_ignore_header_line, 0, 0 },
194 
195     { ngx_string("X-Accel-Limit-Rate"),
196                  ngx_http_upstream_process_limit_rate, 0,
197                  ngx_http_upstream_ignore_header_line, 0, 0 },
198 
199     { ngx_string("X-Accel-Buffering"),
200                  ngx_http_upstream_process_buffering, 0,
201                  ngx_http_upstream_ignore_header_line, 0, 0 },
202 
203     { ngx_string("X-Accel-Charset"),
204                  ngx_http_upstream_process_charset, 0,
205                  ngx_http_upstream_ignore_header_line, 0, 0 },
206 
207 #if (NGX_HTTP_GZIP)
208     { ngx_string("Content-Encoding"),
209                  ngx_http_upstream_process_header_line,
210                  offsetof(ngx_http_upstream_headers_in_t, content_encoding),
211                  ngx_http_upstream_copy_content_encoding, 0, 0 },
212 #endif
213 
214     { ngx_null_string, NULL, 0, NULL, 0, 0 }
215 };
216 
217 
218 static ngx_command_t  ngx_http_upstream_commands[] = {
219 
220     { ngx_string("upstream"),
221       NGX_HTTP_MAIN_CONF|NGX_CONF_BLOCK|NGX_CONF_TAKE1,
222       ngx_http_upstream,
223       0,
224       0,
225       NULL },
226 
227     { ngx_string("server"),
228       NGX_HTTP_UPS_CONF|NGX_CONF_1MORE,
229       ngx_http_upstream_server,
230       NGX_HTTP_SRV_CONF_OFFSET,
231       0,
232       NULL },
233 
234       ngx_null_command
235 };
236 
237 
238 static ngx_http_module_t  ngx_http_upstream_module_ctx = {
239     ngx_http_upstream_add_variables,       /* preconfiguration */
240     NULL,                                  /* postconfiguration */
241 
242     ngx_http_upstream_create_main_conf,    /* create main configuration */
243     ngx_http_upstream_init_main_conf,      /* init main configuration */
244 
245     NULL,                                  /* create server configuration */
246     NULL,                                  /* merge server configuration */
247 
248     NULL,                                  /* create location configuration */
249     NULL                                   /* merge location configuration */
250 };
251 
252 
253 ngx_module_t  ngx_http_upstream_module = {
254     NGX_MODULE_V1,
255     &ngx_http_upstream_module_ctx,         /* module context */
256     ngx_http_upstream_commands,            /* module directives */
257     NGX_HTTP_MODULE,                       /* module type */
258     NULL,                                  /* init master */
259     NULL,                                  /* init module */
260     NULL,                                  /* init process */
261     NULL,                                  /* init thread */
262     NULL,                                  /* exit thread */
263     NULL,                                  /* exit process */
264     NULL,                                  /* exit master */
265     NGX_MODULE_V1_PADDING
266 };
267 
268 
269 static ngx_http_variable_t  ngx_http_upstream_vars[] = {
270 
271     { ngx_string("upstream_addr"), NULL,
272       ngx_http_upstream_addr_variable, 0, NGX_HTTP_VAR_NOHASH, 0 },
273 
274     { ngx_string("upstream_status"), NULL,
275       ngx_http_upstream_status_variable, 0, NGX_HTTP_VAR_NOHASH, 0 },
276 
277     { ngx_string("upstream_response_time"), NULL,
278       ngx_http_upstream_response_time_variable, 0, NGX_HTTP_VAR_NOHASH, 0 },
279 
280     { ngx_null_string, NULL, NULL, 0, 0, 0 }
281 };
282 
283 
284 void
285 ngx_http_upstream_init(ngx_http_request_t *r)
286 {
287     ngx_str_t                      *host;
288     ngx_uint_t                      i;
289     ngx_connection_t               *c;
290     ngx_resolver_ctx_t             *ctx, temp;
291     ngx_http_cleanup_t             *cln;
292     ngx_http_upstream_t            *u;
293     ngx_http_core_loc_conf_t       *clcf;
294     ngx_http_upstream_srv_conf_t   *uscf, **uscfp;
295     ngx_http_upstream_main_conf_t  *umcf;
296 
297     c = r->connection;
298 
299     ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
300                    "http init upstream, client timer: %d", c->read->timer_set);
301 
302     if (c->read->timer_set) {
303         ngx_del_timer(c->read);
304     }
305 
306     u = r->upstream;
307 
308     if (!r->post_action && !u->conf->ignore_client_abort) {
309         r->read_event_handler = ngx_http_upstream_rd_check_broken_connection;
310         r->write_event_handler = ngx_http_upstream_wr_check_broken_connection;
311     }
312 
313     if (ngx_event_flags & NGX_USE_CLEAR_EVENT) {
314 
315         if (!c->write->active) {
316             if (ngx_add_event(c->write, NGX_WRITE_EVENT, NGX_CLEAR_EVENT)
317                 == NGX_ERROR)
318             {
319                 ngx_http_finalize_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
320                 return;
321             }
322         }
323     }
324 
325     if (r->request_body) {
326         u->request_bufs = r->request_body->bufs;
327     }
328 
329     if (u->create_request(r) != NGX_OK) {
330         ngx_http_finalize_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
331         return;
332     }
333 
334     clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
335 
336     u->output.sendfile = c->sendfile;
337     u->output.pool = r->pool;
338     u->output.bufs.num = 1;
339     u->output.bufs.size = clcf->client_body_buffer_size;
340     u->output.output_filter = ngx_chain_writer;
341     u->output.filter_ctx = &u->writer;
342 
343     u->writer.pool = r->pool;
344 
345     if (r->upstream_states == NULL) {
346 
347         r->upstream_states = ngx_array_create(r->pool, 1,
348                                             sizeof(ngx_http_upstream_state_t));
349         if (r->upstream_states == NULL) {
350             ngx_http_finalize_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
351             return;
352         }
353 
354     } else {
355 
356         u->state = ngx_array_push(r->upstream_states);
357         if (u->state == NULL) {
358             ngx_http_upstream_finalize_request(r, u,
359                                                NGX_HTTP_INTERNAL_SERVER_ERROR);
360             return;
361         }
362 
363         ngx_memzero(u->state, sizeof(ngx_http_upstream_state_t));
364     }
365 
366     cln = ngx_http_cleanup_add(r, 0);
367     if (cln == NULL) {
368         ngx_http_finalize_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
369         return;
370     }
371 
372     cln->handler = ngx_http_upstream_cleanup;
373     cln->data = r;
374     u->cleanup = &cln->handler;
375 
376     u->store = (u->conf->store || u->conf->store_lengths);
377 
378     if (u->resolved == NULL) {
379 
380         uscf = u->conf->upstream;
381 
382     } else {
383 
384         host = &u->resolved->host;
385 
386         umcf = ngx_http_get_module_main_conf(r, ngx_http_upstream_module);
387 
388         uscfp = umcf->upstreams.elts;
389 
390         for (i = 0; i < umcf->upstreams.nelts; i++) {
391 
392             uscf = uscfp[i];
393 
394             if (uscf->host.len == host->len
395                 && ngx_memcmp(uscf->host.data, host->data, host->len) == 0)
396             {
397                 goto found;
398             }
399         }
400 
401         temp.name = *host;
402 
403         ctx = ngx_resolve_start(clcf->resolver, &temp);
404         if (ctx == NULL) {
405             ngx_http_finalize_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
406             return;
407         }
408 
409         if (ctx == NGX_NO_RESOLVER) {
410             ngx_log_error(NGX_LOG_ERR, c->log, 0,
411                           "no resolver defined to resolve %V", host);
412 
413             ngx_http_finalize_request(r, NGX_HTTP_BAD_GATEWAY);
414             return;
415         }
416 
417         ctx->name = *host;
418         ctx->type = NGX_RESOLVE_A;
419         ctx->handler = ngx_http_upstream_resolve_handler;
420         ctx->data = r;
421         ctx->timeout = clcf->resolver_timeout;
422 
423         u->resolved->ctx = ctx;
424 
425         if (ngx_resolve_name(ctx) != NGX_OK) {
426             ngx_http_finalize_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
427             return;
428         }
429 
430         return;
431     }
432 
433 found:
434 
435     if (uscf->peer.init(r, uscf) != NGX_OK) {
436         ngx_http_finalize_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
437         return;
438     }
439 
440     ngx_http_upstream_connect(r, u);
441 }
442 
443 
444 static void
445 ngx_http_upstream_resolve_handler(ngx_resolver_ctx_t *ctx)
446 {
447     ngx_http_request_t            *r;
448     ngx_http_upstream_resolved_t  *ur;
449 
450     r = ctx->data;
451 
452     r->upstream->resolved->ctx = NULL;
453 
454     if (ctx->state) {
455         ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
456                       "%V could not be resolved (%i: %s)",
457                       &ctx->name, ctx->state,
458                       ngx_resolver_strerror(ctx->state));
459 
460         ngx_resolve_name_done(ctx);
461         ngx_http_finalize_request(r, NGX_HTTP_BAD_GATEWAY);
462         return;
463     }
464 
465     ur = r->upstream->resolved;
466     ur->naddrs = ctx->naddrs;
467     ur->addrs = ctx->addrs;
468 
469 #if (NGX_DEBUG)
470     {
471     in_addr_t   addr;
472     ngx_uint_t  i;
473 
474     for (i = 0; i < ctx->naddrs; i++) {
475         addr = ntohl(ur->addrs[i]);
476 
477         ngx_log_debug4(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
478                        "name was resolved to %ud.%ud.%ud.%ud",
479                        (addr >> 24) & 0xff, (addr >> 16) & 0xff,
480                        (addr >> 8) & 0xff, addr & 0xff);
481     }
482     }
483 #endif
484 
485     if (ngx_http_upstream_create_round_robin_peer(r, ur) != NGX_OK) {
486         ngx_resolve_name_done(ctx);
487         ngx_http_finalize_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
488         return;
489     }
490 
491     ngx_resolve_name_done(ctx);
492 
493     ngx_http_upstream_connect(r, r->upstream);
494 }
495 
496 
497 static void
498 ngx_http_upstream_rd_check_broken_connection(ngx_http_request_t *r)
499 {
500     ngx_http_upstream_check_broken_connection(r, r->connection->read);
501 }
502 
503 
504 static void
505 ngx_http_upstream_wr_check_broken_connection(ngx_http_request_t *r)
506 {
507     ngx_http_upstream_check_broken_connection(r, r->connection->write);
508 }
509 
510 
511 static void
512 ngx_http_upstream_check_broken_connection(ngx_http_request_t *r,
513     ngx_event_t *ev)
514 {
515     int                  n;
516     char                 buf[1];
517     ngx_err_t            err;
518     ngx_connection_t     *c;
519     ngx_http_upstream_t  *u;
520 
521     ngx_log_debug2(NGX_LOG_DEBUG_HTTP, ev->log, 0,
522                    "http upstream check client, write event:%d, \"%V\"",
523                    ev->write, &r->uri);
524 
525     c = r->connection;
526     u = r->upstream;
527 
528     if (c->error) {
529         ngx_http_upstream_finalize_request(r, u,
530                                            NGX_HTTP_CLIENT_CLOSED_REQUEST);
531         return;
532     }
533 
534     if (u->peer.connection == NULL) {
535         return;
536     }
537 
538 #if (NGX_HAVE_KQUEUE)
539 
540     if (ngx_event_flags & NGX_USE_KQUEUE_EVENT) {
541 
542         if (!ev->pending_eof) {
543             return;
544         }
545 
546         ev->eof = 1;
547         c->error = 1;
548 
549         if (ev->kq_errno) {
550             ev->error = 1;
551         }
552 
553         if (!u->cacheable && !u->store && u->peer.connection) {
554             ngx_log_error(NGX_LOG_INFO, ev->log, ev->kq_errno,
555                           "kevent() reported that client closed prematurely "
556                           "connection, so upstream connection is closed too");
557             ngx_http_upstream_finalize_request(r, u,
558                                                NGX_HTTP_CLIENT_CLOSED_REQUEST);
559             return;
560         }
561 
562         ngx_log_error(NGX_LOG_INFO, ev->log, ev->kq_errno,
563                       "kevent() reported that client closed "
564                       "prematurely connection");
565 
566         if (u->peer.connection == NULL) {
567             ngx_http_upstream_finalize_request(r, u,
568                                                NGX_HTTP_CLIENT_CLOSED_REQUEST);
569             return;
570         }
571 
572         return;
573     }
574 
575 #endif
576 
577     n = recv(c->fd, buf, 1, MSG_PEEK);
578 
579     err = ngx_socket_errno;
580 
581     ngx_log_debug1(NGX_LOG_DEBUG_HTTP, ev->log, err,
582                    "http upstream recv(): %d", n);
583 
584     /*
585      * we do not need to disable the write event because
586      * that event has NGX_USE_CLEAR_EVENT type
587      */
588 
589     if (ev->write && (n >= 0 || err == NGX_EAGAIN)) {
590         return;
591     }
592 
593     if ((ngx_event_flags & NGX_USE_LEVEL_EVENT) && ev->active) {
594         if (ngx_del_event(ev, NGX_READ_EVENT, 0) == NGX_ERROR) {
595             ngx_http_upstream_finalize_request(r, u,
596                                                NGX_HTTP_INTERNAL_SERVER_ERROR);
597             return;
598         }
599     }
600 
601     if (n > 0) {
602         return;
603     }
604 
605     if (n == -1) {
606         if (err == NGX_EAGAIN) {
607             return;
608         }
609 
610         ev->error = 1;
611 
612     } else { /* n == 0 */
613         err = 0;
614     }
615 
616     ev->eof = 1;
617     c->error = 1;
618 
619     if (!u->cacheable && !u->store && u->peer.connection) {
620         ngx_log_error(NGX_LOG_INFO, ev->log, err,
621                       "client closed prematurely connection, "
622                       "so upstream connection is closed too");
623         ngx_http_upstream_finalize_request(r, u,
624                                            NGX_HTTP_CLIENT_CLOSED_REQUEST);
625         return;
626     }
627 
628     ngx_log_error(NGX_LOG_INFO, ev->log, err,
629                   "client closed prematurely connection");
630 
631     if (u->peer.connection == NULL) {
632         ngx_http_upstream_finalize_request(r, u,
633                                            NGX_HTTP_CLIENT_CLOSED_REQUEST);
634         return;
635     }
636 }
637 
638 
639 static void
640 ngx_http_upstream_connect(ngx_http_request_t *r, ngx_http_upstream_t *u)
641 {
642     ngx_int_t          rc;
643     ngx_time_t        *tp;
644     ngx_connection_t  *c;
645 
646     r->connection->log->action = "connecting to upstream";
647 
648     r->connection->single_connection = 0;
649 
650     if (u->state && u->state->response_sec) {
651         tp = ngx_timeofday();
652         u->state->response_sec = tp->sec - u->state->response_sec;
653         u->state->response_msec = tp->msec - u->state->response_msec;
654     }
655 
656     u->state = ngx_array_push(r->upstream_states);
657     if (u->state == NULL) {
658         ngx_http_upstream_finalize_request(r, u,
659                                            NGX_HTTP_INTERNAL_SERVER_ERROR);
660         return;
661     }
662 
663     ngx_memzero(u->state, sizeof(ngx_http_upstream_state_t));
664 
665     tp = ngx_timeofday();
666     u->state->response_sec = tp->sec;
667     u->state->response_msec = tp->msec;
668 
669     rc = ngx_event_connect_peer(&u->peer);
670 
671     ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
672                    "http upstream connect: %i", rc);
673 
674     if (rc == NGX_ERROR) {
675         ngx_http_upstream_finalize_request(r, u,
676                                            NGX_HTTP_INTERNAL_SERVER_ERROR);
677         return;
678     }
679 
680     u->state->peer = u->peer.name;
681 
682     if (rc == NGX_BUSY) {
683         ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "no live upstreams");
684         ngx_http_upstream_next(r, u, NGX_HTTP_UPSTREAM_FT_NOLIVE);
685         return;
686     }
687 
688     if (rc == NGX_DECLINED) {
689         ngx_http_upstream_next(r, u, NGX_HTTP_UPSTREAM_FT_ERROR);
690         return;
691     }
692 
693     /* rc == NGX_OK || rc == NGX_AGAIN */
694 
695     c = u->peer.connection;
696 
697     c->data = r;
698 
699     c->write->handler = ngx_http_upstream_send_request_handler;
700     c->read->handler = ngx_http_upstream_process_header;
701 
702     c->sendfile &= r->connection->sendfile;
703 
704     c->pool = r->pool;
705     c->read->log = c->write->log = c->log = r->connection->log;
706 
707     /* init or reinit the ngx_output_chain() and ngx_chain_writer() contexts */
708 
709     u->writer.out = NULL;
710     u->writer.last = &u->writer.out;
711     u->writer.connection = c;
712     u->writer.limit = 0;
713 
714     if (u->request_sent) {
715         if (ngx_http_upstream_reinit(r, u) != NGX_OK) {
716             ngx_http_upstream_finalize_request(r, u,
717                                                NGX_HTTP_INTERNAL_SERVER_ERROR);
718             return;
719         }
720     }
721 
722     if (r->request_body
723         && r->request_body->buf
724         && r->request_body->temp_file
725         && r == r->main)
726     {
727         /*
728          * the r->request_body->buf can be reused for one request only,
729          * the subrequests should allocate their own temporay bufs
730          */
731 
732         u->output.free = ngx_alloc_chain_link(r->pool);
733         if (u->output.free == NULL) {
734             ngx_http_upstream_finalize_request(r, u,
735                                                NGX_HTTP_INTERNAL_SERVER_ERROR);
736             return;
737         }
738 
739         u->output.free->buf = r->request_body->buf;
740         u->output.free->next = NULL;
741         u->output.allocated = 1;
742 
743         r->request_body->buf->pos = r->request_body->buf->start;
744         r->request_body->buf->last = r->request_body->buf->start;
745         r->request_body->buf->tag = u->output.tag;
746     }
747 
748     u->request_sent = 0;
749 
750     if (rc == NGX_AGAIN) {
751         ngx_add_timer(c->write, u->conf->connect_timeout);
752         return;
753     }
754 
755 #if (NGX_HTTP_SSL)
756 
757     if (u->ssl && c->ssl == NULL) {
758         ngx_http_upstream_ssl_init_connection(r, u, c);
759         return;
760     }
761 
762 #endif
763 
764     ngx_http_upstream_send_request(r, u);
765 }
766 
767 
768 #if (NGX_HTTP_SSL)
769 
770 static void
771 ngx_http_upstream_ssl_init_connection(ngx_http_request_t *r,
772     ngx_http_upstream_t *u, ngx_connection_t *c)
773 {
774     ngx_int_t   rc;
775 
776     if (ngx_ssl_create_connection(u->conf->ssl, c,
777                                   NGX_SSL_BUFFER|NGX_SSL_CLIENT)
778         == NGX_ERROR)
779     {
780         ngx_http_upstream_finalize_request(r, u,
781                                            NGX_HTTP_INTERNAL_SERVER_ERROR);
782         return;
783     }
784 
785     c->sendfile = 0;
786     u->output.sendfile = 0;
787 
788     if (u->peer.set_session(&u->peer, u->peer.data) != NGX_OK) {
789         ngx_http_upstream_finalize_request(r, u,
790                                            NGX_HTTP_INTERNAL_SERVER_ERROR);
791         return;
792     }
793 
794     r->connection->log->action = "SSL handshaking to upstream";
795 
796     rc = ngx_ssl_handshake(c);
797 
798     if (rc == NGX_AGAIN) {
799         c->ssl->handler = ngx_http_upstream_ssl_handshake;
800         return;
801     }
802 
803     ngx_http_upstream_ssl_handshake(c);
804 }
805 
806 
807 static void
808 ngx_http_upstream_ssl_handshake(ngx_connection_t *c)
809 {
810     ngx_http_request_t   *r;
811     ngx_http_upstream_t  *u;
812 
813     r = c->data;
814     u = r->upstream;
815 
816     if (c->ssl->handshaked) {
817 
818         u->peer.save_session(&u->peer, u->peer.data);
819 
820         c->write->handler = ngx_http_upstream_send_request_handler;
821         c->read->handler = ngx_http_upstream_process_header;
822 
823         ngx_http_upstream_send_request(r, u);
824 
825         return;
826     }
827 
828     ngx_http_upstream_next(r, u, NGX_HTTP_UPSTREAM_FT_ERROR);
829 
830 }
831 
832 #endif
833 
834 
835 static ngx_int_t
836 ngx_http_upstream_reinit(ngx_http_request_t *r, ngx_http_upstream_t *u)
837 {
838     ngx_chain_t  *cl;
839 
840     if (u->reinit_request(r) != NGX_OK) {
841         return NGX_ERROR;
842     }
843 
844     ngx_memzero(&u->headers_in, sizeof(ngx_http_upstream_headers_in_t));
845 
846     if (ngx_list_init(&u->headers_in.headers, r->pool, 8,
847                       sizeof(ngx_table_elt_t))
848         != NGX_OK)
849     {
850         return NGX_ERROR;
851     }
852 
853     /* reinit the request chain */
854 
855     for (cl = u->request_bufs; cl; cl = cl->next) {
856         cl->buf->pos = cl->buf->start;
857         cl->buf->file_pos = 0;
858     }
859 
860     /* reinit the subrequest's ngx_output_chain() context */
861 
862     if (r->request_body && r->request_body->temp_file
863         && r != r->main && u->output.buf)
864     {
865         u->output.free = ngx_alloc_chain_link(r->pool);
866         if (u->output.free == NULL) {
867             return NGX_ERROR;
868         }
869 
870         u->output.free->buf = u->output.buf;
871         u->output.free->next = NULL;
872 
873         u->output.buf->pos = u->output.buf->start;
874         u->output.buf->last = u->output.buf->start;
875     }
876 
877     u->output.buf = NULL;
878     u->output.in = NULL;
879     u->output.busy = NULL;
880 
881     /* reinit u->buffer */
882 
883 #if 0
884     if (u->cache) {
885         u->buffer.pos = u->buffer.start + u->cache->ctx.header_size;
886         u->buffer.last = u->buffer.pos;
887 
888     } else {
889         u->buffer.pos = u->buffer.start;
890         u->buffer.last = u->buffer.start;
891     }
892 #else
893 
894         u->buffer.pos = u->buffer.start;
895         u->buffer.last = u->buffer.start;
896 
897 #endif
898 
899     return NGX_OK;
900 }
901 
902 
903 static void
904 ngx_http_upstream_send_request(ngx_http_request_t *r, ngx_http_upstream_t *u)
905 {
906     ngx_int_t          rc;
907     ngx_connection_t  *c;
908 
909     c = u->peer.connection;
910 
911     ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0,
912                    "http upstream send request");
913 
914     if (!u->request_sent && ngx_http_upstream_test_connect(c) != NGX_OK) {
915         ngx_http_upstream_next(r, u, NGX_HTTP_UPSTREAM_FT_ERROR);
916         return;
917     }
918 
919     c->log->action = "sending request to upstream";
920 
921     rc = ngx_output_chain(&u->output, u->request_sent ? NULL : u->request_bufs);
922 
923     u->request_sent = 1;
924 
925     if (rc == NGX_ERROR) {
926         ngx_http_upstream_next(r, u, NGX_HTTP_UPSTREAM_FT_ERROR);
927         return;
928     }
929 
930     if (c->write->timer_set) {
931         ngx_del_timer(c->write);
932     }
933 
934     if (rc == NGX_AGAIN) {
935         ngx_add_timer(c->write, u->conf->send_timeout);
936 
937         if (ngx_handle_write_event(c->write, u->conf->send_lowat) == NGX_ERROR)
938         {
939             ngx_http_upstream_finalize_request(r, u,
940                                                NGX_HTTP_INTERNAL_SERVER_ERROR);
941             return;
942         }
943 
944         return;
945     }
946 
947     /* rc == NGX_OK */
948 
949     if (c->tcp_nopush == NGX_TCP_NOPUSH_SET) {
950         if (ngx_tcp_push(c->fd) == NGX_ERROR) {
951             ngx_log_error(NGX_LOG_CRIT, c->log, ngx_socket_errno,
952                           ngx_tcp_push_n " failed");
953             ngx_http_upstream_finalize_request(r, u,
954                                                NGX_HTTP_INTERNAL_SERVER_ERROR);
955             return;
956         }
957 
958         c->tcp_nopush = NGX_TCP_NOPUSH_UNSET;
959     }
960 
961     ngx_add_timer(c->read, u->conf->read_timeout);
962