xref: /lighttpd1.4/src/mod_proxy.c (revision fcf0dc3e)
1 #include "first.h"
2 
3 #include <string.h>
4 #include <stdlib.h>
5 
6 #include "gw_backend.h"
7 #include "base.h"
8 #include "array.h"
9 #include "buffer.h"
10 #include "fdevent.h"
11 #include "http_kv.h"
12 #include "http_header.h"
13 #include "log.h"
14 #include "sock_addr.h"
15 
16 /**
17  *
18  * HTTP reverse proxy
19  *
20  * TODO:      - HTTP/1.1
21  *            - HTTP/1.1 persistent connection with upstream servers
22  */
23 
24 /* (future: might split struct and move part to http-header-glue.c) */
25 typedef struct http_header_remap_opts {
26     const array *urlpaths;
27     const array *hosts_request;
28     const array *hosts_response;
29     int force_http10;
30     int https_remap;
31     int upgrade;
32     int connect_method;
33     /*(not used in plugin_config, but used in handler_ctx)*/
34     const buffer *http_host;
35     const buffer *forwarded_host;
36     const data_string *forwarded_urlpath;
37 } http_header_remap_opts;
38 
39 typedef enum {
40 	PROXY_FORWARDED_NONE         = 0x00,
41 	PROXY_FORWARDED_FOR          = 0x01,
42 	PROXY_FORWARDED_PROTO        = 0x02,
43 	PROXY_FORWARDED_HOST         = 0x04,
44 	PROXY_FORWARDED_BY           = 0x08,
45 	PROXY_FORWARDED_REMOTE_USER  = 0x10
46 } proxy_forwarded_t;
47 
48 typedef struct {
49     gw_plugin_config gw; /* start must match layout of gw_plugin_config */
50     unsigned int replace_http_host;
51     unsigned int forwarded;
52     http_header_remap_opts header;
53 } plugin_config;
54 
55 typedef struct {
56     PLUGIN_DATA;
57     pid_t srv_pid; /* must match layout of gw_plugin_data through conf member */
58     plugin_config conf;
59     plugin_config defaults;
60 } plugin_data;
61 
62 static int proxy_check_extforward;
63 
64 typedef struct {
65 	gw_handler_ctx gw;
66 	plugin_config conf;
67 } handler_ctx;
68 
69 
70 INIT_FUNC(mod_proxy_init) {
71     return calloc(1, sizeof(plugin_data));
72 }
73 
74 
75 static void mod_proxy_free_config(plugin_data * const p)
76 {
77     if (NULL == p->cvlist) return;
78     /* (init i to 0 if global context; to 1 to skip empty global context) */
79     for (int i = !p->cvlist[0].v.u2[1], used = p->nconfig; i < used; ++i) {
80         config_plugin_value_t *cpv = p->cvlist + p->cvlist[i].v.u2[0];
81         for (; -1 != cpv->k_id; ++cpv) {
82             switch (cpv->k_id) {
83               case 5: /* proxy.header */
84                 if (cpv->vtype == T_CONFIG_LOCAL) free(cpv->v.v);
85                 break;
86               default:
87                 break;
88             }
89         }
90     }
91 }
92 
93 
94 FREE_FUNC(mod_proxy_free) {
95     plugin_data * const p = p_d;
96     mod_proxy_free_config(p);
97     gw_free(p);
98 }
99 
100 static void mod_proxy_merge_config_cpv(plugin_config * const pconf, const config_plugin_value_t * const cpv)
101 {
102     switch (cpv->k_id) { /* index into static config_plugin_keys_t cpk[] */
103       case 0: /* proxy.server */
104         if (cpv->vtype == T_CONFIG_LOCAL) {
105             gw_plugin_config * const gw = cpv->v.v;
106             pconf->gw.exts      = gw->exts;
107             pconf->gw.exts_auth = gw->exts_auth;
108             pconf->gw.exts_resp = gw->exts_resp;
109         }
110         break;
111       case 1: /* proxy.balance */
112         /*if (cpv->vtype == T_CONFIG_LOCAL)*//*always true here for this param*/
113             pconf->gw.balance = (int)cpv->v.u;
114         break;
115       case 2: /* proxy.debug */
116         pconf->gw.debug = (int)cpv->v.u;
117         break;
118       case 3: /* proxy.map-extensions */
119         pconf->gw.ext_mapping = cpv->v.a;
120         break;
121       case 4: /* proxy.forwarded */
122         /*if (cpv->vtype == T_CONFIG_LOCAL)*//*always true here for this param*/
123             pconf->forwarded = cpv->v.u;
124         break;
125       case 5: /* proxy.header */
126         /*if (cpv->vtype == T_CONFIG_LOCAL)*//*always true here for this param*/
127         pconf->header = *(http_header_remap_opts *)cpv->v.v; /*(copies struct)*/
128         break;
129       case 6: /* proxy.replace-http-host */
130         pconf->replace_http_host = cpv->v.u;
131         break;
132       default:/* should not happen */
133         return;
134     }
135 }
136 
137 
138 static void mod_proxy_merge_config(plugin_config * const pconf, const config_plugin_value_t *cpv)
139 {
140     do {
141         mod_proxy_merge_config_cpv(pconf, cpv);
142     } while ((++cpv)->k_id != -1);
143 }
144 
145 
146 static void mod_proxy_patch_config(request_st * const r, plugin_data * const p)
147 {
148     memcpy(&p->conf, &p->defaults, sizeof(plugin_config));
149     for (int i = 1, used = p->nconfig; i < used; ++i) {
150         if (config_check_cond(r, (uint32_t)p->cvlist[i].k_id))
151             mod_proxy_merge_config(&p->conf, p->cvlist+p->cvlist[i].v.u2[0]);
152     }
153 }
154 
155 
156 static unsigned int mod_proxy_parse_forwarded(server *srv, const array *a)
157 {
158     unsigned int forwarded = 0;
159     for (uint32_t j = 0, used = a->used; j < used; ++j) {
160         proxy_forwarded_t param;
161         data_unset *du = a->data[j];
162         if (buffer_eq_slen(&du->key, CONST_STR_LEN("by")))
163             param = PROXY_FORWARDED_BY;
164         else if (buffer_eq_slen(&du->key, CONST_STR_LEN("for")))
165             param = PROXY_FORWARDED_FOR;
166         else if (buffer_eq_slen(&du->key, CONST_STR_LEN("host")))
167             param = PROXY_FORWARDED_HOST;
168         else if (buffer_eq_slen(&du->key, CONST_STR_LEN("proto")))
169             param = PROXY_FORWARDED_PROTO;
170         else if (buffer_eq_slen(&du->key, CONST_STR_LEN("remote_user")))
171             param = PROXY_FORWARDED_REMOTE_USER;
172         else {
173             log_error(srv->errh, __FILE__, __LINE__,
174               "proxy.forwarded keys must be one of: "
175               "by, for, host, proto, remote_user, but not: %s", du->key.ptr);
176             return UINT_MAX;
177         }
178         int val = config_plugin_value_tobool(du, 2);
179         if (2 == val) {
180             log_error(srv->errh, __FILE__, __LINE__,
181               "proxy.forwarded values must be one of: "
182               "0, 1, enable, disable; error for key: %s", du->key.ptr);
183             return UINT_MAX;
184         }
185         if (val)
186             forwarded |= param;
187     }
188     return forwarded;
189 }
190 
191 
192 static http_header_remap_opts * mod_proxy_parse_header_opts(server *srv, const array *a)
193 {
194     http_header_remap_opts header;
195     memset(&header, 0, sizeof(header));
196     for (uint32_t j = 0, used = a->used; j < used; ++j) {
197         data_array *da = (data_array *)a->data[j];
198         if (buffer_eq_slen(&da->key, CONST_STR_LEN("https-remap"))) {
199             int val = config_plugin_value_tobool((data_unset *)da, 2);
200             if (2 == val) {
201                 log_error(srv->errh, __FILE__, __LINE__,
202                   "unexpected value for proxy.header; "
203                   "expected \"https-remap\" => \"enable\" or \"disable\"");
204                 return NULL;
205             }
206             header.https_remap = val;
207             continue;
208         }
209         else if (buffer_eq_slen(&da->key, CONST_STR_LEN("force-http10"))) {
210             int val = config_plugin_value_tobool((data_unset *)da, 2);
211             if (2 == val) {
212                 log_error(srv->errh, __FILE__, __LINE__,
213                   "unexpected value for proxy.header; "
214                   "expected \"force-http10\" => \"enable\" or \"disable\"");
215                 return NULL;
216             }
217             header.force_http10 = val;
218             continue;
219         }
220         else if (buffer_eq_slen(&da->key, CONST_STR_LEN("upgrade"))) {
221             int val = config_plugin_value_tobool((data_unset *)da, 2);
222             if (2 == val) {
223                 log_error(srv->errh, __FILE__, __LINE__,
224                   "unexpected value for proxy.header; "
225                   "expected \"upgrade\" => \"enable\" or \"disable\"");
226                 return NULL;
227             }
228             header.upgrade = val;
229             continue;
230         }
231         else if (buffer_eq_slen(&da->key, CONST_STR_LEN("connect"))) {
232             int val = config_plugin_value_tobool((data_unset *)da, 2);
233             if (2 == val) {
234                 log_error(srv->errh, __FILE__, __LINE__,
235                   "unexpected value for proxy.header; "
236                   "expected \"connect\" => \"enable\" or \"disable\"");
237                 return NULL;
238             }
239             header.connect_method = val;
240             continue;
241         }
242         if (da->type != TYPE_ARRAY || !array_is_kvstring(&da->value)) {
243             log_error(srv->errh, __FILE__, __LINE__,
244               "unexpected value for proxy.header; "
245               "expected ( \"param\" => ( \"key\" => \"value\" ) ) near key %s",
246               da->key.ptr);
247             return NULL;
248         }
249         if (buffer_eq_slen(&da->key, CONST_STR_LEN("map-urlpath"))) {
250             header.urlpaths = &da->value;
251         }
252         else if (buffer_eq_slen(&da->key, CONST_STR_LEN("map-host-request"))) {
253             header.hosts_request = &da->value;
254         }
255         else if (buffer_eq_slen(&da->key, CONST_STR_LEN("map-host-response"))) {
256             header.hosts_response = &da->value;
257         }
258         else {
259             log_error(srv->errh, __FILE__, __LINE__,
260               "unexpected key for proxy.header; "
261               "expected ( \"param\" => ( \"key\" => \"value\" ) ) near key %s",
262               da->key.ptr);
263             return NULL;
264         }
265     }
266 
267     http_header_remap_opts *opts = malloc(sizeof(header));
268     force_assert(opts);
269     memcpy(opts, &header, sizeof(header));
270     return opts;
271 }
272 
273 
274 SETDEFAULTS_FUNC(mod_proxy_set_defaults)
275 {
276     static const config_plugin_keys_t cpk[] = {
277       { CONST_STR_LEN("proxy.server"),
278         T_CONFIG_ARRAY_KVARRAY,
279         T_CONFIG_SCOPE_CONNECTION }
280      ,{ CONST_STR_LEN("proxy.balance"),
281         T_CONFIG_STRING,
282         T_CONFIG_SCOPE_CONNECTION }
283      ,{ CONST_STR_LEN("proxy.debug"),
284         T_CONFIG_INT,
285         T_CONFIG_SCOPE_CONNECTION }
286      ,{ CONST_STR_LEN("proxy.map-extensions"),
287         T_CONFIG_ARRAY_KVSTRING,
288         T_CONFIG_SCOPE_CONNECTION }
289      ,{ CONST_STR_LEN("proxy.forwarded"),
290         T_CONFIG_ARRAY_KVANY,
291         T_CONFIG_SCOPE_CONNECTION }
292      ,{ CONST_STR_LEN("proxy.header"),
293         T_CONFIG_ARRAY_KVANY,
294         T_CONFIG_SCOPE_CONNECTION }
295      ,{ CONST_STR_LEN("proxy.replace-http-host"),
296         T_CONFIG_BOOL,
297         T_CONFIG_SCOPE_CONNECTION }
298      ,{ NULL, 0,
299         T_CONFIG_UNSET,
300         T_CONFIG_SCOPE_UNSET }
301     };
302 
303     plugin_data * const p = p_d;
304     if (!config_plugin_values_init(srv, p, cpk, "mod_proxy"))
305         return HANDLER_ERROR;
306 
307     /* process and validate config directives
308      * (init i to 0 if global context; to 1 to skip empty global context) */
309     for (int i = !p->cvlist[0].v.u2[1]; i < p->nconfig; ++i) {
310         config_plugin_value_t *cpv = p->cvlist + p->cvlist[i].v.u2[0];
311         gw_plugin_config *gw = NULL;
312         for (; -1 != cpv->k_id; ++cpv) {
313             switch (cpv->k_id) {
314               case 0: /* proxy.server */
315                 gw = calloc(1, sizeof(gw_plugin_config));
316                 force_assert(gw);
317                 if (!gw_set_defaults_backend(srv, (gw_plugin_data *)p, cpv->v.a,
318                                              gw, 0, cpk[cpv->k_id].k)) {
319                     gw_plugin_config_free(gw);
320                     return HANDLER_ERROR;
321                 }
322                 /* error if "mode" = "authorizer";
323                  * proxy can not act as authorizer */
324                 /*(check after gw_set_defaults_backend())*/
325                 if (gw->exts_auth && gw->exts_auth->used) {
326                     log_error(srv->errh, __FILE__, __LINE__,
327                       "%s must not define any hosts with "
328                       "attribute \"mode\" = \"authorizer\"", cpk[cpv->k_id].k);
329                     gw_plugin_config_free(gw);
330                     return HANDLER_ERROR;
331                 }
332                 cpv->v.v = gw;
333                 cpv->vtype = T_CONFIG_LOCAL;
334                 break;
335               case 1: /* proxy.balance */
336                 cpv->v.u = (unsigned int)gw_get_defaults_balance(srv, cpv->v.b);
337                 break;
338               case 2: /* proxy.debug */
339               case 3: /* proxy.map-extensions */
340                 break;
341               case 4: /* proxy.forwarded */
342                 cpv->v.u = mod_proxy_parse_forwarded(srv, cpv->v.a);
343                 if (UINT_MAX == cpv->v.u) return HANDLER_ERROR;
344                 cpv->vtype = T_CONFIG_LOCAL;
345                 break;
346               case 5: /* proxy.header */
347                 cpv->v.v = mod_proxy_parse_header_opts(srv, cpv->v.a);
348                 if (NULL == cpv->v.v) return HANDLER_ERROR;
349                 cpv->vtype = T_CONFIG_LOCAL;
350                 break;
351               case 6: /* proxy.replace-http-host */
352                 break;
353               default:/* should not happen */
354                 break;
355             }
356         }
357 
358         /* disable check-local for all exts (default enabled) */
359         if (gw && gw->exts) { /*(check after gw_set_defaults_backend())*/
360             gw_exts_clear_check_local(gw->exts);
361         }
362     }
363 
364     /* default is 0 */
365     /*p->defaults.balance = (unsigned int)gw_get_defaults_balance(srv, NULL);*/
366 
367     p->defaults.header.force_http10 =
368       config_feature_bool(srv, "proxy.force-http10", 0);
369 
370     /* initialize p->defaults from global config context */
371     if (p->nconfig > 0 && p->cvlist->v.u2[1]) {
372         const config_plugin_value_t *cpv = p->cvlist + p->cvlist->v.u2[0];
373         if (-1 != cpv->k_id)
374             mod_proxy_merge_config(&p->defaults, cpv);
375     }
376 
377     /* special-case behavior if mod_extforward is loaded */
378     for (uint32_t i = 0; i < srv->srvconf.modules->used; ++i) {
379         buffer *m = &((data_string *)srv->srvconf.modules->data[i])->value;
380         if (buffer_eq_slen(m, CONST_STR_LEN("mod_extforward"))) {
381             proxy_check_extforward = 1;
382             break;
383         }
384     }
385 
386     return HANDLER_GO_ON;
387 }
388 
389 
390 /* (future: might move to http-header-glue.c) */
391 static const buffer * http_header_remap_host_match (buffer *b, size_t off, http_header_remap_opts *remap_hdrs, int is_req, size_t alen)
392 {
393     const array *hosts = is_req
394       ? remap_hdrs->hosts_request
395       : remap_hdrs->hosts_response;
396     if (hosts) {
397         const char * const s = b->ptr+off;
398         for (size_t i = 0, used = hosts->used; i < used; ++i) {
399             const data_string * const ds = (data_string *)hosts->data[i];
400             const buffer *k = &ds->key;
401             size_t mlen = buffer_clen(k);
402             if (1 == mlen && k->ptr[0] == '-') {
403                 /* match with authority provided in Host (if is_req)
404                  * (If no Host in client request, then matching against empty
405                  *  string will probably not match, and no remap will be
406                  *  performed) */
407                 k = is_req
408                   ? remap_hdrs->http_host
409                   : remap_hdrs->forwarded_host;
410                 if (NULL == k) continue;
411                 mlen = buffer_clen(k);
412             }
413             if (buffer_eq_icase_ss(s, alen, k->ptr, mlen)) {
414                 if (buffer_is_equal_string(&ds->value, CONST_STR_LEN("-"))) {
415                     return remap_hdrs->http_host;
416                 }
417                 else if (!buffer_is_blank(&ds->value)) {
418                     /*(save first matched request host for response match)*/
419                     if (is_req && NULL == remap_hdrs->forwarded_host)
420                         remap_hdrs->forwarded_host = &ds->value;
421                     return &ds->value;
422                 } /*(else leave authority as-is and stop matching)*/
423                 break;
424             }
425         }
426     }
427     return NULL;
428 }
429 
430 
431 /* (future: might move to http-header-glue.c) */
432 static size_t http_header_remap_host (buffer *b, size_t off, http_header_remap_opts *remap_hdrs, int is_req, size_t alen)
433 {
434     const buffer * const m =
435       http_header_remap_host_match(b, off, remap_hdrs, is_req, alen);
436     if (NULL == m) return alen; /*(no match; return original authority length)*/
437 
438     buffer_substr_replace(b, off, alen, m);
439     return buffer_clen(m); /*(length of replacement authority)*/
440 }
441 
442 
443 /* (future: might move to http-header-glue.c) */
444 static size_t http_header_remap_urlpath (buffer *b, size_t off, http_header_remap_opts *remap_hdrs, int is_req)
445 {
446     const array *urlpaths = remap_hdrs->urlpaths;
447     if (urlpaths) {
448         const char * const s = b->ptr+off;
449         const size_t plen = buffer_clen(b) - off; /*(urlpath len)*/
450         if (is_req) { /* request */
451             for (size_t i = 0, used = urlpaths->used; i < used; ++i) {
452                 const data_string * const ds = (data_string *)urlpaths->data[i];
453                 const size_t mlen = buffer_clen(&ds->key);
454                 if (mlen <= plen && 0 == memcmp(s, ds->key.ptr, mlen)) {
455                     if (NULL == remap_hdrs->forwarded_urlpath)
456                         remap_hdrs->forwarded_urlpath = ds;
457                     buffer_substr_replace(b, off, mlen, &ds->value);
458                     return buffer_clen(&ds->value);/*(replacement len)*/
459                 }
460             }
461         }
462         else {        /* response; perform reverse map */
463             if (NULL != remap_hdrs->forwarded_urlpath) {
464                 const data_string * const ds = remap_hdrs->forwarded_urlpath;
465                 const size_t mlen = buffer_clen(&ds->value);
466                 if (mlen <= plen && 0 == memcmp(s, ds->value.ptr, mlen)) {
467                     buffer_substr_replace(b, off, mlen, &ds->key);
468                     return buffer_clen(&ds->key); /*(replacement len)*/
469                 }
470             }
471             for (size_t i = 0, used = urlpaths->used; i < used; ++i) {
472                 const data_string * const ds = (data_string *)urlpaths->data[i];
473                 const size_t mlen = buffer_clen(&ds->value);
474                 if (mlen <= plen && 0 == memcmp(s, ds->value.ptr, mlen)) {
475                     buffer_substr_replace(b, off, mlen, &ds->key);
476                     return buffer_clen(&ds->key); /*(replacement len)*/
477                 }
478             }
479         }
480     }
481     return 0;
482 }
483 
484 
485 /* (future: might move to http-header-glue.c) */
486 static void http_header_remap_uri (buffer *b, size_t off, http_header_remap_opts *remap_hdrs, int is_req)
487 {
488     /* find beginning of URL-path (might be preceded by scheme://authority
489      * (caller should make sure any leading whitespace is prior to offset) */
490     if (b->ptr[off] != '/') {
491         char *s = b->ptr+off;
492         size_t alen; /*(authority len (host len))*/
493         size_t slen; /*(scheme len)*/
494         const buffer *m;
495         /* skip over scheme and authority of URI to find beginning of URL-path
496          * (value might conceivably be relative URL-path instead of URI) */
497         if (NULL == (s = strchr(s, ':')) || s[1] != '/' || s[2] != '/') return;
498         slen = s - (b->ptr+off);
499         s += 3;
500         off = (size_t)(s - b->ptr);
501         if (NULL != (s = strchr(s, '/'))) {
502             alen = (size_t)(s - b->ptr) - off;
503             if (0 == alen) return; /*(empty authority, e.g. "http:///")*/
504         }
505         else {
506             alen = buffer_clen(b) - off;
507             if (0 == alen) return; /*(empty authority, e.g. "http:///")*/
508             buffer_append_char(b, '/');
509         }
510 
511         /* remap authority (if configured) and set offset to url-path */
512         m = http_header_remap_host_match(b, off, remap_hdrs, is_req, alen);
513         if (NULL != m) {
514             if (remap_hdrs->https_remap
515                 && (is_req ? 5==slen && 0==memcmp(b->ptr+off-slen-3,"https",5)
516                            : 4==slen && 0==memcmp(b->ptr+off-slen-3,"http",4))){
517                 if (is_req) {
518                     memcpy(b->ptr+off-slen-3+4,"://",3);  /*("https"=>"http")*/
519                     --off;
520                     ++alen;
521                 }
522                 else {/*(!is_req)*/
523                     memcpy(b->ptr+off-slen-3+4,"s://",4); /*("http" =>"https")*/
524                     ++off;
525                     --alen;
526                 }
527             }
528             buffer_substr_replace(b, off, alen, m);
529             alen = buffer_clen(m);/*(length of replacement authority)*/
530         }
531         off += alen;
532     }
533 
534     /* remap URLs (if configured) */
535     http_header_remap_urlpath(b, off, remap_hdrs, is_req);
536 }
537 
538 
539 /* (future: might move to http-header-glue.c) */
540 static void http_header_remap_setcookie (buffer *b, size_t off, http_header_remap_opts *remap_hdrs)
541 {
542     /* Given the special-case of Set-Cookie and the (too) loosely restricted
543      * characters allowed, for best results, the Set-Cookie value should be the
544      * entire string in b from offset to end of string.  In response headers,
545      * lighttpd may concatenate multiple Set-Cookie headers into single entry
546      * in r->resp_headers, separated by "\r\nSet-Cookie: " */
547     for (char *s = b->ptr+off, *e; *s; s = e) {
548         size_t len;
549         {
550             while (*s != ';' && *s != '\n' && *s != '\0') ++s;
551             if (*s == '\n') {
552                 /*(include +1 for '\n', but leave ' ' for ++s below)*/
553                 s += sizeof("Set-Cookie:");
554             }
555             if ('\0' == *s) return;
556             do { ++s; } while (*s == ' ' || *s == '\t');
557             if ('\0' == *s) return;
558             e = s+1;
559             if ('=' == *s) continue;
560             /*(interested only in Domain and Path attributes)*/
561             while (*e != '=' && *e != '\0') ++e;
562             if ('\0' == *e) return;
563             ++e;
564             switch ((int)(e - s - 1)) {
565               case 4:
566                 if (buffer_eq_icase_ssn(s, "path", 4)) {
567                     if (*e == '"') ++e;
568                     if (*e != '/') continue;
569                     off = (size_t)(e - b->ptr);
570                     len = http_header_remap_urlpath(b, off, remap_hdrs, 0);
571                     e = b->ptr+off+len; /*(b may have been reallocated)*/
572                     continue;
573                 }
574                 break;
575               case 6:
576                 if (buffer_eq_icase_ssn(s, "domain", 6)) {
577                     size_t alen = 0;
578                     if (*e == '"') ++e;
579                     if (*e == '.') ++e;
580                     if (*e == ';') continue;
581                     off = (size_t)(e - b->ptr);
582                     for (char c; (c = e[alen]) != ';' && c != ' ' && c != '\t'
583                                           && c != '\r' && c != '\0'; ++alen);
584                     len = http_header_remap_host(b, off, remap_hdrs, 0, alen);
585                     e = b->ptr+off+len; /*(b may have been reallocated)*/
586                     continue;
587                 }
588                 break;
589               default:
590                 break;
591             }
592         }
593     }
594 }
595 
596 
597 static void buffer_append_string_backslash_escaped(buffer *b, const char *s, size_t len) {
598     /* (future: might move to buffer.c) */
599     size_t j = 0;
600     char * const p = buffer_string_prepare_append(b, len*2 + 4);
601 
602     for (size_t i = 0; i < len; ++i) {
603         int c = s[i];
604         if (c == '"' || c == '\\' || c == 0x7F || (c < 0x20 && c != '\t'))
605             p[j++] = '\\';
606         p[j++] = c;
607     }
608 
609     buffer_commit(b, j);
610 }
611 
612 static void proxy_set_Forwarded(connection * const con, request_st * const r, const unsigned int flags) {
613     buffer *b = NULL;
614     buffer * const efor = (proxy_check_extforward)
615       ? http_header_env_get(r, CONST_STR_LEN("_L_EXTFORWARD_ACTUAL_FOR"))
616       : NULL;
617     int semicolon = 0;
618 
619     /* note: set "Forwarded" prior to updating X-Forwarded-For (below) */
620 
621     if (flags)
622         b = http_header_request_get(r, HTTP_HEADER_FORWARDED, CONST_STR_LEN("Forwarded"));
623 
624     if (flags && NULL == b) {
625         const buffer *xff =
626           http_header_request_get(r, HTTP_HEADER_X_FORWARDED_FOR, CONST_STR_LEN("X-Forwarded-For"));
627         b = http_header_request_set_ptr(r, HTTP_HEADER_FORWARDED,
628                                         CONST_STR_LEN("Forwarded"));
629         if (NULL != xff) {
630             /* use X-Forwarded-For contents to seed Forwarded */
631             char *s = xff->ptr;
632             size_t used = buffer_clen(xff);
633             for (size_t i=0, j, ipv6; i < used; ++i) {
634                 while (s[i] == ' ' || s[i] == '\t' || s[i] == ',') ++i;
635                 if (s[i] == '\0') break;
636                 j = i;
637                 do {
638                     ++i;
639                 } while (s[i]!=' ' && s[i]!='\t' && s[i]!=',' && s[i]!='\0');
640                 /* over-simplified test expecting only IPv4 or IPv6 addresses,
641                  * (not expecting :port, so treat existence of colon as IPv6,
642                  *  and not expecting unix paths, especially not containing ':')
643                  * quote all strings, backslash-escape since IPs not validated*/
644                 ipv6 = (NULL != memchr(s+j, ':', i-j)); /*(over-simplified) */
645                 ipv6
646                   ? buffer_append_string_len(b, CONST_STR_LEN("for=\"["))
647                   : buffer_append_string_len(b, CONST_STR_LEN("for=\""));
648                 buffer_append_string_backslash_escaped(b, s+j, i-j);
649                 ipv6
650                   ? buffer_append_string_len(b, CONST_STR_LEN("]\", "))
651                   : buffer_append_string_len(b, CONST_STR_LEN("\", "));
652             }
653         }
654     } else if (flags) { /*(NULL != b)*/
655         buffer_append_string_len(b, CONST_STR_LEN(", "));
656     }
657 
658     if (flags & PROXY_FORWARDED_FOR) {
659         int family = sock_addr_get_family(&con->dst_addr);
660         buffer_append_string_len(b, CONST_STR_LEN("for="));
661         if (NULL != efor) {
662             /* over-simplified test expecting only IPv4 or IPv6 addresses,
663              * (not expecting :port, so treat existence of colon as IPv6,
664              *  and not expecting unix paths, especially not containing ':')
665              * quote all strings and backslash-escape since IPs not validated
666              * (should be IP from original con->dst_addr_buf,
667              *  so trustable and without :port) */
668             int ipv6 = (NULL != strchr(efor->ptr, ':'));
669             ipv6
670               ? buffer_append_string_len(b, CONST_STR_LEN("\"["))
671               : buffer_append_char(b, '"');
672             buffer_append_string_backslash_escaped(b, BUF_PTR_LEN(efor));
673             ipv6
674               ? buffer_append_string_len(b, CONST_STR_LEN("]\""))
675               : buffer_append_char(b, '"');
676         } else if (family == AF_INET) {
677             /*(Note: if :port is added, then must be quoted-string:
678              * e.g. for="...:port")*/
679             buffer_append_string_buffer(b, &con->dst_addr_buf);
680         } else if (family == AF_INET6) {
681             buffer_append_str3(b, CONST_STR_LEN("\"["),
682                                   BUF_PTR_LEN(&con->dst_addr_buf),
683                                   CONST_STR_LEN("]\""));
684         } else {
685             buffer_append_char(b, '"');
686             buffer_append_string_backslash_escaped(
687               b, BUF_PTR_LEN(&con->dst_addr_buf));
688             buffer_append_char(b, '"');
689         }
690         semicolon = 1;
691     }
692 
693     if (flags & PROXY_FORWARDED_BY) {
694         int family = sock_addr_get_family(&con->srv_socket->addr);
695         /* Note: getsockname() and inet_ntop() are expensive operations.
696          * (recommendation: do not to enable by=... unless required)
697          * future: might use con->srv_socket->srv_token if addr is not
698          *   INADDR_ANY or in6addr_any, but must omit optional :port
699          *   from con->srv_socket->srv_token for consistency */
700 
701         if (semicolon) buffer_append_char(b, ';');
702         buffer_append_string_len(b, CONST_STR_LEN("by=\""));
703       #ifdef HAVE_SYS_UN_H
704         /* special-case: might need to encode unix domain socket path */
705         if (family == AF_UNIX) {
706             buffer_append_string_backslash_escaped(
707               b, BUF_PTR_LEN(con->srv_socket->srv_token));
708         }
709         else
710       #endif
711         {
712             sock_addr addr;
713             socklen_t addrlen = sizeof(addr);
714             if (0 == getsockname(con->fd,(struct sockaddr *)&addr, &addrlen)) {
715                 sock_addr_stringify_append_buffer(b, &addr);
716             }
717         }
718         buffer_append_char(b, '"');
719         semicolon = 1;
720     }
721 
722     if (flags & PROXY_FORWARDED_PROTO) {
723         const buffer * const eproto = (proxy_check_extforward)
724           ? http_header_env_get(r, CONST_STR_LEN("_L_EXTFORWARD_ACTUAL_PROTO"))
725           : NULL;
726         /* expecting "http" or "https"
727          * (not checking if quoted-string and encoding needed) */
728         if (semicolon) buffer_append_char(b, ';');
729         if (NULL != eproto) {
730             buffer_append_str2(b, CONST_STR_LEN("proto="), BUF_PTR_LEN(eproto));
731         } else if (con->srv_socket->is_ssl) {
732             buffer_append_string_len(b, CONST_STR_LEN("proto=https"));
733         } else {
734             buffer_append_string_len(b, CONST_STR_LEN("proto=http"));
735         }
736         semicolon = 1;
737     }
738 
739     if (flags & PROXY_FORWARDED_HOST) {
740         const buffer * const ehost = (proxy_check_extforward)
741           ? http_header_env_get(r, CONST_STR_LEN("_L_EXTFORWARD_ACTUAL_HOST"))
742           : NULL;
743         if (NULL != ehost) {
744             if (semicolon)
745                 buffer_append_char(b, ';');
746             buffer_append_string_len(b, CONST_STR_LEN("host=\""));
747             buffer_append_string_backslash_escaped(
748               b, BUF_PTR_LEN(ehost));
749             buffer_append_char(b, '"');
750             semicolon = 1;
751         } else if (r->http_host && !buffer_is_blank(r->http_host)) {
752             if (semicolon)
753                 buffer_append_char(b, ';');
754             buffer_append_string_len(b, CONST_STR_LEN("host=\""));
755             buffer_append_string_backslash_escaped(
756               b, BUF_PTR_LEN(r->http_host));
757             buffer_append_char(b, '"');
758             semicolon = 1;
759         }
760     }
761 
762     if (flags & PROXY_FORWARDED_REMOTE_USER) {
763         const buffer *remote_user =
764           http_header_env_get(r, CONST_STR_LEN("REMOTE_USER"));
765         if (NULL != remote_user) {
766             if (semicolon)
767                 buffer_append_char(b, ';');
768             buffer_append_string_len(b, CONST_STR_LEN("remote_user=\""));
769             buffer_append_string_backslash_escaped(
770               b, BUF_PTR_LEN(remote_user));
771             buffer_append_char(b, '"');
772             /*semicolon = 1;*/
773         }
774     }
775 
776     /* legacy X-* headers, including X-Forwarded-For */
777 
778     b = (NULL != efor) ? efor : &con->dst_addr_buf;
779     http_header_request_append(r, HTTP_HEADER_X_FORWARDED_FOR,
780                                CONST_STR_LEN("X-Forwarded-For"),
781                                BUF_PTR_LEN(b));
782 
783     b = r->http_host;
784     if (b && !buffer_is_blank(b)) {
785         http_header_request_set(r, HTTP_HEADER_OTHER,
786                                 CONST_STR_LEN("X-Host"),
787                                 BUF_PTR_LEN(b));
788         http_header_request_set(r, HTTP_HEADER_OTHER,
789                                 CONST_STR_LEN("X-Forwarded-Host"),
790                                 BUF_PTR_LEN(b));
791     }
792 
793     b = &r->uri.scheme;
794     http_header_request_set(r, HTTP_HEADER_X_FORWARDED_PROTO,
795                             CONST_STR_LEN("X-Forwarded-Proto"),
796                             BUF_PTR_LEN(b));
797 }
798 
799 
800 static handler_t proxy_stdin_append(gw_handler_ctx *hctx) {
801     /*handler_ctx *hctx = (handler_ctx *)gwhctx;*/
802     chunkqueue * const req_cq = &hctx->r->reqbody_queue;
803     const off_t req_cqlen = chunkqueue_length(req_cq);
804     if (req_cqlen) {
805         /* XXX: future: use http_chunk_len_append() */
806         buffer * const tb = hctx->r->tmp_buf;
807         buffer_clear(tb);
808         buffer_append_uint_hex_lc(tb, (uintmax_t)req_cqlen);
809         buffer_append_string_len(tb, CONST_STR_LEN("\r\n"));
810 
811         const off_t len = (off_t)buffer_clen(tb)
812                         + 2 /*(+2 end chunk "\r\n")*/
813                         + req_cqlen;
814         if (-1 != hctx->wb_reqlen)
815             hctx->wb_reqlen += (hctx->wb_reqlen >= 0) ? len : -len;
816 
817         (chunkqueue_is_empty(&hctx->wb) || hctx->wb.first->type == MEM_CHUNK)
818                                           /* else FILE_CHUNK for temp file */
819           ? chunkqueue_append_mem(&hctx->wb, BUF_PTR_LEN(tb))
820           : chunkqueue_append_mem_min(&hctx->wb, BUF_PTR_LEN(tb));
821         chunkqueue_steal(&hctx->wb, req_cq, req_cqlen);
822 
823         chunkqueue_append_mem_min(&hctx->wb, CONST_STR_LEN("\r\n"));
824     }
825 
826     if (hctx->wb.bytes_in == hctx->wb_reqlen) {/*hctx->r->reqbody_length >= 0*/
827         /* terminate STDIN */
828         chunkqueue_append_mem(&hctx->wb, CONST_STR_LEN("0\r\n\r\n"));
829         hctx->wb_reqlen += (int)sizeof("0\r\n\r\n");
830     }
831 
832     return HANDLER_GO_ON;
833 }
834 
835 
836 static handler_t proxy_create_env(gw_handler_ctx *gwhctx) {
837 	handler_ctx *hctx = (handler_ctx *)gwhctx;
838 	request_st * const r = hctx->gw.r;
839 	const int remap_headers = (NULL != hctx->conf.header.urlpaths
840 				   || NULL != hctx->conf.header.hosts_request);
841 	size_t rsz = (size_t)(r->read_queue.bytes_out - hctx->gw.wb.bytes_in);
842 	if (rsz >= 65536) rsz = r->rqst_header_len;
843 	buffer * const b = chunkqueue_prepend_buffer_open_sz(&hctx->gw.wb, rsz);
844 
845 	/* build header */
846 
847 	/* request line */
848 	const buffer * const m =
849 	  http_method_buf(!r->h2_connect_ext
850 			  ? r->http_method
851 			  : HTTP_METHOD_GET); /*(translate HTTP/2 CONNECT ext)*/
852 	buffer_append_str3(b,
853 	                   BUF_PTR_LEN(m),
854 	                   CONST_STR_LEN(" "),
855 	                   BUF_PTR_LEN(&r->target));
856 	if (remap_headers)
857 		http_header_remap_uri(b, buffer_clen(b) - buffer_clen(&r->target),
858 		                      &hctx->conf.header, 1);
859 
860 	buffer_append_string_len(b, !hctx->conf.header.force_http10
861 	                            ? " HTTP/1.1" : " HTTP/1.0",
862 	                            sizeof(" HTTP/1.1")-1);
863 
864 	if (hctx->conf.replace_http_host && !buffer_is_blank(hctx->gw.host->id)) {
865 		if (hctx->gw.conf.debug > 1) {
866 			log_error(r->conf.errh, __FILE__, __LINE__,
867 			  "proxy - using \"%s\" as HTTP Host", hctx->gw.host->id->ptr);
868 		}
869 		buffer_append_str2(b, CONST_STR_LEN("\r\nHost: "),
870 		                      BUF_PTR_LEN(hctx->gw.host->id));
871 	} else if (r->http_host && !buffer_is_unset(r->http_host)) {
872 		buffer_append_str2(b, CONST_STR_LEN("\r\nHost: "),
873 		                      BUF_PTR_LEN(r->http_host));
874 		if (remap_headers) {
875 			size_t alen = buffer_clen(r->http_host);
876 			http_header_remap_host(b, buffer_clen(b) - alen, &hctx->conf.header, 1, alen);
877 		}
878 	} else {
879 		/* no Host header available; must send HTTP/1.0 request */
880 		b->ptr[b->used-2] = '0'; /*(overwrite end of request line)*/
881 	}
882 
883 	if (r->reqbody_length > 0
884 	    || (0 == r->reqbody_length
885 		&& !http_method_get_or_head(r->http_method))) {
886 		/* set Content-Length if client sent Transfer-Encoding: chunked
887 		 * and not streaming to backend (request body has been fully received) */
888 		const buffer *vb = http_header_request_get(r, HTTP_HEADER_CONTENT_LENGTH, CONST_STR_LEN("Content-Length"));
889 		if (NULL == vb) {
890 			buffer_append_int(
891 			  http_header_request_set_ptr(r, HTTP_HEADER_CONTENT_LENGTH,
892 			                              CONST_STR_LEN("Content-Length")),
893 			  r->reqbody_length);
894 		}
895 	}
896 	else if (r->h2_connect_ext) {
897 	}
898 	else if (-1 == r->reqbody_length
899 	         && (r->conf.stream_request_body
900 	             & (FDEVENT_STREAM_REQUEST | FDEVENT_STREAM_REQUEST_BUFMIN))) {
901 		if (__builtin_expect( (hctx->conf.header.force_http10), 0))
902 			return http_response_reqbody_read_error(r, 411);
903 		hctx->gw.stdin_append = proxy_stdin_append; /* stream chunked body */
904 		buffer_append_string_len(b, CONST_STR_LEN("\r\nTransfer-Encoding: chunked"));
905 	}
906 
907 	/* "Forwarded" and legacy X- headers */
908 	proxy_set_Forwarded(r->con, r, hctx->conf.forwarded);
909 
910 	/* request header */
911 	const buffer *connhdr = NULL;
912 	const buffer *te = NULL;
913 	const buffer *upgrade = NULL;
914 	for (size_t i = 0, used = r->rqst_headers.used; i < used; ++i) {
915 		const data_string * const ds = (data_string *)r->rqst_headers.data[i];
916 		switch (ds->ext) {
917 		default:
918 			break;
919 		case HTTP_HEADER_HOST:
920 			continue; /*(handled further above)*/
921 		case HTTP_HEADER_OTHER:
922 			if (__builtin_expect( ('p' == (ds->key.ptr[0] | 0x20)), 0)) {
923 				if (buffer_eq_icase_slen(&ds->key, CONST_STR_LEN("Proxy-Connection"))) continue;
924 				/* Do not emit HTTP_PROXY in environment.
925 				 * Some executables use HTTP_PROXY to configure
926 				 * outgoing proxy.  See also https://httpoxy.org/ */
927 				if (buffer_eq_icase_slen(&ds->key, CONST_STR_LEN("Proxy"))) continue;
928 			}
929 			break;
930 		case HTTP_HEADER_TE:
931 			if (hctx->conf.header.force_http10 || r->http_version == HTTP_VERSION_1_0) continue;
932 			/* ignore if not exactly "trailers" */
933 			if (!buffer_eq_icase_slen(&ds->value, CONST_STR_LEN("trailers"))) continue;
934 			/*if (!buffer_is_blank(&ds->value)) te = &ds->value;*/
935 			te = &ds->value; /*("trailers")*/
936 			break;
937 		case HTTP_HEADER_UPGRADE:
938 			if (hctx->conf.header.force_http10
939 			    || (r->http_version != HTTP_VERSION_1_1 && !r->h2_connect_ext))
940 				continue;
941 			if (!hctx->conf.header.upgrade) continue;
942 			if (!buffer_is_blank(&ds->value)) upgrade = &ds->value;
943 			break;
944 		case HTTP_HEADER_CONNECTION:
945 			connhdr = &ds->value;
946 			continue;
947 		case HTTP_HEADER_SET_COOKIE:
948 			continue; /*(response header only; avoid accidental reflection)*/
949 		}
950 
951 		const uint32_t klen = buffer_clen(&ds->key);
952 		const uint32_t vlen = buffer_clen(&ds->value);
953 		if (0 == klen || 0 == vlen) continue;
954 		char * restrict s = buffer_extend(b, klen+vlen+4);
955 		s[0] = '\r';
956 		s[1] = '\n';
957 		memcpy(s+2, ds->key.ptr, klen);
958 		s += 2+klen;
959 		s[0] = ':';
960 		s[1] = ' ';
961 		memcpy(s+2, ds->value.ptr, vlen);
962 
963 		if (!remap_headers) continue;
964 
965 		/* check for hdrs for which to remap URIs in-place after append to b */
966 
967 		switch (klen) {
968 		default:
969 			continue;
970 	      #if 0 /* "URI" is HTTP response header (non-standard; historical in Apache) */
971 		case 3:
972 			if (ds->ext == HTTP_HEADER_OTHER && buffer_eq_icase_slen(&ds->key, CONST_STR_LEN("URI"))) break;
973 			continue;
974 	      #endif
975 	      #if 0 /* "Location" is HTTP response header */
976 		case 8:
977 			if (ds->ext == HTTP_HEADER_LOCATION) break;
978 			continue;
979 	      #endif
980 		case 11: /* "Destination" is WebDAV request header */
981 			if (ds->ext == HTTP_HEADER_OTHER && buffer_eq_icase_slen(&ds->key, CONST_STR_LEN("Destination"))) break;
982 			continue;
983 		case 16: /* "Content-Location" may be HTTP request or response header */
984 			if (ds->ext == HTTP_HEADER_CONTENT_LOCATION) break;
985 			continue;
986 		}
987 
988 		http_header_remap_uri(b, buffer_clen(b) - vlen, &hctx->conf.header, 1);
989 	}
990 
991 	if (connhdr && !hctx->conf.header.force_http10 && r->http_version >= HTTP_VERSION_1_1
992 	    && !buffer_eq_icase_slen(connhdr, CONST_STR_LEN("close"))) {
993 		/* mod_proxy always sends Connection: close to backend */
994 		buffer_append_string_len(b, CONST_STR_LEN("\r\nConnection: close"));
995 		/* (future: might be pedantic and also check Connection header for each
996 		 * token using http_header_str_contains_token() */
997 		if (te)
998 			buffer_append_string_len(b, CONST_STR_LEN(", te"));
999 		if (upgrade)
1000 			buffer_append_string_len(b, CONST_STR_LEN(", upgrade"));
1001 		buffer_append_string_len(b, CONST_STR_LEN("\r\n\r\n"));
1002 	}
1003 	else if (r->h2_connect_ext) {
1004 		/* https://datatracker.ietf.org/doc/html/rfc6455#section-4.1
1005 		 * 7. The request MUST include a header field with the name
1006 		 *    |Sec-WebSocket-Key|.  The value of this header field MUST be a
1007 		 *    nonce consisting of a randomly selected 16-byte value that has
1008 		 *    been base64-encoded (see Section 4 of [RFC4648]).  The nonce
1009 		 *    MUST be selected randomly for each connection.
1010 		 * Note: Sec-WebSocket-Key is not used in RFC8441;
1011 		 *       include Sec-WebSocket-Key for HTTP/1.1 compatibility;
1012 		 *       !!not random!! base64-encoded "0000000000000000" */
1013 		if (!http_header_request_get(r, HTTP_HEADER_OTHER,
1014 		                             CONST_STR_LEN("Sec-WebSocket-Key")))
1015 			buffer_append_string_len(b, CONST_STR_LEN(
1016 			  "\r\nSec-WebSocket-Key: MDAwMDAwMDAwMDAwMDAwMA=="));
1017 		buffer_append_string_len(b, CONST_STR_LEN(
1018 		                              "\r\nUpgrade: websocket"
1019 		                              "\r\nConnection: close, upgrade\r\n\r\n"));
1020 	}
1021 	else    /* mod_proxy always sends Connection: close to backend */
1022 		buffer_append_string_len(b, CONST_STR_LEN("\r\nConnection: close\r\n\r\n"));
1023 
1024 	hctx->gw.wb_reqlen = buffer_clen(b);
1025 	chunkqueue_prepend_buffer_commit(&hctx->gw.wb);
1026 
1027 	if (r->reqbody_length) {
1028 		if (r->reqbody_length > 0)
1029 			hctx->gw.wb_reqlen += r->reqbody_length; /* total req size */
1030 		else /* as-yet-unknown total request size (Transfer-Encoding: chunked)*/
1031 			hctx->gw.wb_reqlen = -hctx->gw.wb_reqlen;
1032 		if (hctx->gw.stdin_append == proxy_stdin_append)
1033 			proxy_stdin_append(&hctx->gw);
1034 		else
1035 			chunkqueue_append_chunkqueue(&hctx->gw.wb, &r->reqbody_queue);
1036 	}
1037 
1038 	plugin_stats_inc("proxy.requests");
1039 	return HANDLER_GO_ON;
1040 }
1041 
1042 
1043 static handler_t proxy_create_env_connect(gw_handler_ctx *gwhctx) {
1044 	handler_ctx *hctx = (handler_ctx *)gwhctx;
1045 	request_st * const r = hctx->gw.r;
1046 	r->http_status = 200; /* OK */
1047 	r->resp_body_started = 1;
1048 	gw_set_transparent(&hctx->gw);
1049 	http_response_upgrade_read_body_unknown(r);
1050 
1051 	plugin_stats_inc("proxy.requests");
1052 	return HANDLER_GO_ON;
1053 }
1054 
1055 
1056 static handler_t proxy_response_headers(request_st * const r, struct http_response_opts_t *opts) {
1057     /* response headers just completed */
1058     handler_ctx *hctx = (handler_ctx *)opts->pdata;
1059     http_header_remap_opts * const remap_hdrs = &hctx->conf.header;
1060 
1061     if (light_btst(r->resp_htags, HTTP_HEADER_UPGRADE)) {
1062         if (remap_hdrs->upgrade && r->http_status == 101) {
1063             /* 101 Switching Protocols; transition to transparent proxy */
1064             if (r->h2_connect_ext) {
1065                 r->http_status = 200; /* OK (response status for CONNECT) */
1066                 http_header_response_unset(r, HTTP_HEADER_UPGRADE,
1067                                            CONST_STR_LEN("Upgrade"));
1068                 http_header_response_unset(r, HTTP_HEADER_OTHER,
1069                                          CONST_STR_LEN("Sec-WebSocket-Accept"));
1070             }
1071             gw_set_transparent(&hctx->gw);
1072             http_response_upgrade_read_body_unknown(r);
1073         }
1074         else {
1075             light_bclr(r->resp_htags, HTTP_HEADER_UPGRADE);
1076           #if 0
1077             /* preserve prior questionable behavior; likely broken behavior
1078              * anyway if backend thinks connection is being upgraded but client
1079              * does not receive Connection: upgrade */
1080             http_header_response_unset(r, HTTP_HEADER_UPGRADE,
1081                                        CONST_STR_LEN("Upgrade"))
1082           #endif
1083         }
1084     }
1085     else if (__builtin_expect( (r->h2_connect_ext != 0), 0)
1086              && r->http_status < 300) {
1087         /*(not handling other 1xx intermediate responses here; not expected)*/
1088         http_response_body_clear(r, 0);
1089         r->handler_module = NULL;
1090         r->http_status = 405; /* Method Not Allowed */
1091         return HANDLER_FINISHED;
1092     }
1093 
1094     /* rewrite paths, if needed */
1095 
1096     if (NULL == remap_hdrs->urlpaths && NULL == remap_hdrs->hosts_response)
1097         return HANDLER_GO_ON;
1098 
1099     buffer *vb;
1100     if (light_btst(r->resp_htags, HTTP_HEADER_LOCATION)) {
1101         vb = http_header_response_get(r, HTTP_HEADER_LOCATION,
1102                                          CONST_STR_LEN("Location"));
1103         if (vb) http_header_remap_uri(vb, 0, remap_hdrs, 0);
1104     }
1105     if (light_btst(r->resp_htags, HTTP_HEADER_CONTENT_LOCATION)) {
1106         vb = http_header_response_get(r, HTTP_HEADER_CONTENT_LOCATION,
1107                                          CONST_STR_LEN("Content-Location"));
1108         if (vb) http_header_remap_uri(vb, 0, remap_hdrs, 0);
1109     }
1110     if (light_btst(r->resp_htags, HTTP_HEADER_SET_COOKIE)) {
1111         vb = http_header_response_get(r, HTTP_HEADER_SET_COOKIE,
1112                                          CONST_STR_LEN("Set-Cookie"));
1113         if (vb) http_header_remap_setcookie(vb, 0, remap_hdrs);
1114     }
1115 
1116     return HANDLER_GO_ON;
1117 }
1118 
1119 static handler_t mod_proxy_check_extension(request_st * const r, void *p_d) {
1120 	plugin_data *p = p_d;
1121 	handler_t rc;
1122 
1123 	if (NULL != r->handler_module) return HANDLER_GO_ON;
1124 
1125 	mod_proxy_patch_config(r, p);
1126 	if (NULL == p->conf.gw.exts) return HANDLER_GO_ON;
1127 
1128 	rc = gw_check_extension(r, (gw_plugin_data *)p, 1, sizeof(handler_ctx));
1129 	if (HANDLER_GO_ON != rc) return rc;
1130 
1131 	if (r->handler_module == p->self) {
1132 		handler_ctx *hctx = r->plugin_ctx[p->id];
1133 		hctx->gw.create_env = proxy_create_env;
1134 		hctx->gw.response = chunk_buffer_acquire();
1135 		hctx->gw.opts.backend = BACKEND_PROXY;
1136 		hctx->gw.opts.pdata = hctx;
1137 		hctx->gw.opts.headers = proxy_response_headers;
1138 
1139 		hctx->conf = p->conf; /*(copies struct)*/
1140 		hctx->conf.header.http_host = r->http_host;
1141 		hctx->conf.header.upgrade  &=
1142                   (r->http_version == HTTP_VERSION_1_1 || r->h2_connect_ext);
1143 		/* mod_proxy currently sends all backend requests as http.
1144 		 * https-remap is a flag since it might not be needed if backend
1145 		 * honors Forwarded or X-Forwarded-Proto headers, e.g. by using
1146 		 * lighttpd mod_extforward or similar functionality in backend*/
1147 		if (hctx->conf.header.https_remap) {
1148 			hctx->conf.header.https_remap =
1149 			  buffer_is_equal_string(&r->uri.scheme, CONST_STR_LEN("https"));
1150 		}
1151 
1152 		if (r->http_method == HTTP_METHOD_CONNECT) {
1153 			/*(note: not requiring HTTP/1.1 due to too many non-compliant
1154 			 * clients such as 'openssl s_client')*/
1155 			if (r->h2_connect_ext
1156 			    && (hctx->conf.header.connect_method =
1157 			          hctx->conf.header.upgrade)) { /*(405 if not set)*/
1158 				/*(not bothering to check (!hctx->conf.header.force_http10))*/
1159 				/*hctx->gw.create_env = proxy_create_env;*/ /*(preserve)*/
1160 			}
1161 			else if (hctx->conf.header.connect_method) {
1162 				hctx->gw.create_env = proxy_create_env_connect;
1163 			}
1164 			else {
1165 				r->http_status = 405; /* Method Not Allowed */
1166 				r->handler_module = NULL;
1167 				return HANDLER_FINISHED;
1168 			}
1169 		}
1170 	}
1171 
1172 	return HANDLER_GO_ON;
1173 }
1174 
1175 
1176 int mod_proxy_plugin_init(plugin *p);
1177 int mod_proxy_plugin_init(plugin *p) {
1178 	p->version      = LIGHTTPD_VERSION_ID;
1179 	p->name         = "proxy";
1180 
1181 	p->init         = mod_proxy_init;
1182 	p->cleanup      = mod_proxy_free;
1183 	p->set_defaults = mod_proxy_set_defaults;
1184 	p->handle_request_reset    = gw_handle_request_reset;
1185 	p->handle_uri_clean        = mod_proxy_check_extension;
1186 	p->handle_subrequest       = gw_handle_subrequest;
1187 	p->handle_trigger          = gw_handle_trigger;
1188 	p->handle_waitpid          = gw_handle_waitpid_cb;
1189 
1190 	return 0;
1191 }
1192