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1 /***************************************************************************
2  *                                  _   _ ____  _
3  *  Project                     ___| | | |  _ \| |
4  *                             / __| | | | |_) | |
5  *                            | (__| |_| |  _ <| |___
6  *                             \___|\___/|_| \_\_____|
7  *
8  * Copyright (C) 1998 - 2021, Daniel Stenberg, <daniel@haxx.se>, et al.
9  *
10  * This software is licensed as described in the file COPYING, which
11  * you should have received as part of this distribution. The terms
12  * are also available at https://curl.se/docs/copyright.html.
13  *
14  * You may opt to use, copy, modify, merge, publish, distribute and/or sell
15  * copies of the Software, and permit persons to whom the Software is
16  * furnished to do so, under the terms of the COPYING file.
17  *
18  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
19  * KIND, either express or implied.
20  *
21  *   'pingpong' is for generic back-and-forth support functions used by FTP,
22  *   IMAP, POP3, SMTP and whatever more that likes them.
23  *
24  ***************************************************************************/
25 
26 #include "curl_setup.h"
27 
28 #include "urldata.h"
29 #include "sendf.h"
30 #include "select.h"
31 #include "progress.h"
32 #include "speedcheck.h"
33 #include "pingpong.h"
34 #include "multiif.h"
35 #include "non-ascii.h"
36 #include "vtls/vtls.h"
37 
38 /* The last 3 #include files should be in this order */
39 #include "curl_printf.h"
40 #include "curl_memory.h"
41 #include "memdebug.h"
42 
43 #ifdef USE_PINGPONG
44 
45 /* Returns timeout in ms. 0 or negative number means the timeout has already
46    triggered */
Curl_pp_state_timeout(struct Curl_easy * data,struct pingpong * pp,bool disconnecting)47 timediff_t Curl_pp_state_timeout(struct Curl_easy *data,
48                                  struct pingpong *pp, bool disconnecting)
49 {
50   struct connectdata *conn = data->conn;
51   timediff_t timeout_ms; /* in milliseconds */
52   timediff_t response_time = (data->set.server_response_timeout)?
53     data->set.server_response_timeout: pp->response_time;
54 
55   /* if CURLOPT_SERVER_RESPONSE_TIMEOUT is set, use that to determine
56      remaining time, or use pp->response because SERVER_RESPONSE_TIMEOUT is
57      supposed to govern the response for any given server response, not for
58      the time from connect to the given server response. */
59 
60   /* Without a requested timeout, we only wait 'response_time' seconds for the
61      full response to arrive before we bail out */
62   timeout_ms = response_time -
63     Curl_timediff(Curl_now(), pp->response); /* spent time */
64 
65   if(data->set.timeout && !disconnecting) {
66     /* if timeout is requested, find out how much remaining time we have */
67     timediff_t timeout2_ms = data->set.timeout - /* timeout time */
68       Curl_timediff(Curl_now(), conn->now); /* spent time */
69 
70     /* pick the lowest number */
71     timeout_ms = CURLMIN(timeout_ms, timeout2_ms);
72   }
73 
74   return timeout_ms;
75 }
76 
77 /*
78  * Curl_pp_statemach()
79  */
Curl_pp_statemach(struct Curl_easy * data,struct pingpong * pp,bool block,bool disconnecting)80 CURLcode Curl_pp_statemach(struct Curl_easy *data,
81                            struct pingpong *pp, bool block,
82                            bool disconnecting)
83 {
84   struct connectdata *conn = data->conn;
85   curl_socket_t sock = conn->sock[FIRSTSOCKET];
86   int rc;
87   timediff_t interval_ms;
88   timediff_t timeout_ms = Curl_pp_state_timeout(data, pp, disconnecting);
89   CURLcode result = CURLE_OK;
90 
91   if(timeout_ms <= 0) {
92     failf(data, "server response timeout");
93     return CURLE_OPERATION_TIMEDOUT; /* already too little time */
94   }
95 
96   if(block) {
97     interval_ms = 1000;  /* use 1 second timeout intervals */
98     if(timeout_ms < interval_ms)
99       interval_ms = timeout_ms;
100   }
101   else
102     interval_ms = 0; /* immediate */
103 
104   if(Curl_ssl_data_pending(conn, FIRSTSOCKET))
105     rc = 1;
106   else if(Curl_pp_moredata(pp))
107     /* We are receiving and there is data in the cache so just read it */
108     rc = 1;
109   else if(!pp->sendleft && Curl_ssl_data_pending(conn, FIRSTSOCKET))
110     /* We are receiving and there is data ready in the SSL library */
111     rc = 1;
112   else
113     rc = Curl_socket_check(pp->sendleft?CURL_SOCKET_BAD:sock, /* reading */
114                            CURL_SOCKET_BAD,
115                            pp->sendleft?sock:CURL_SOCKET_BAD, /* writing */
116                            interval_ms);
117 
118   if(block) {
119     /* if we didn't wait, we don't have to spend time on this now */
120     if(Curl_pgrsUpdate(data))
121       result = CURLE_ABORTED_BY_CALLBACK;
122     else
123       result = Curl_speedcheck(data, Curl_now());
124 
125     if(result)
126       return result;
127   }
128 
129   if(rc == -1) {
130     failf(data, "select/poll error");
131     result = CURLE_OUT_OF_MEMORY;
132   }
133   else if(rc)
134     result = pp->statemachine(data, data->conn);
135 
136   return result;
137 }
138 
139 /* initialize stuff to prepare for reading a fresh new response */
Curl_pp_init(struct Curl_easy * data,struct pingpong * pp)140 void Curl_pp_init(struct Curl_easy *data, struct pingpong *pp)
141 {
142   DEBUGASSERT(data);
143   pp->nread_resp = 0;
144   pp->linestart_resp = data->state.buffer;
145   pp->pending_resp = TRUE;
146   pp->response = Curl_now(); /* start response time-out now! */
147 }
148 
149 /* setup for the coming transfer */
Curl_pp_setup(struct pingpong * pp)150 void Curl_pp_setup(struct pingpong *pp)
151 {
152   Curl_dyn_init(&pp->sendbuf, DYN_PINGPPONG_CMD);
153 }
154 
155 /***********************************************************************
156  *
157  * Curl_pp_vsendf()
158  *
159  * Send the formatted string as a command to a pingpong server. Note that
160  * the string should not have any CRLF appended, as this function will
161  * append the necessary things itself.
162  *
163  * made to never block
164  */
Curl_pp_vsendf(struct Curl_easy * data,struct pingpong * pp,const char * fmt,va_list args)165 CURLcode Curl_pp_vsendf(struct Curl_easy *data,
166                         struct pingpong *pp,
167                         const char *fmt,
168                         va_list args)
169 {
170   ssize_t bytes_written = 0;
171   size_t write_len;
172   char *s;
173   CURLcode result;
174   struct connectdata *conn = data->conn;
175 
176 #ifdef HAVE_GSSAPI
177   enum protection_level data_sec;
178 #endif
179 
180   DEBUGASSERT(pp->sendleft == 0);
181   DEBUGASSERT(pp->sendsize == 0);
182   DEBUGASSERT(pp->sendthis == NULL);
183 
184   if(!conn)
185     /* can't send without a connection! */
186     return CURLE_SEND_ERROR;
187 
188   Curl_dyn_reset(&pp->sendbuf);
189   result = Curl_dyn_vaddf(&pp->sendbuf, fmt, args);
190   if(result)
191     return result;
192 
193   /* append CRLF */
194   result = Curl_dyn_addn(&pp->sendbuf, "\r\n", 2);
195   if(result)
196     return result;
197 
198   write_len = Curl_dyn_len(&pp->sendbuf);
199   s = Curl_dyn_ptr(&pp->sendbuf);
200   Curl_pp_init(data, pp);
201 
202   result = Curl_convert_to_network(data, s, write_len);
203   /* Curl_convert_to_network calls failf if unsuccessful */
204   if(result)
205     return result;
206 
207 #ifdef HAVE_GSSAPI
208   conn->data_prot = PROT_CMD;
209 #endif
210   result = Curl_write(data, conn->sock[FIRSTSOCKET], s, write_len,
211                       &bytes_written);
212   if(result)
213     return result;
214 #ifdef HAVE_GSSAPI
215   data_sec = conn->data_prot;
216   DEBUGASSERT(data_sec > PROT_NONE && data_sec < PROT_LAST);
217   conn->data_prot = data_sec;
218 #endif
219 
220   Curl_debug(data, CURLINFO_HEADER_OUT, s, (size_t)bytes_written);
221 
222   if(bytes_written != (ssize_t)write_len) {
223     /* the whole chunk was not sent, keep it around and adjust sizes */
224     pp->sendthis = s;
225     pp->sendsize = write_len;
226     pp->sendleft = write_len - bytes_written;
227   }
228   else {
229     pp->sendthis = NULL;
230     pp->sendleft = pp->sendsize = 0;
231     pp->response = Curl_now();
232   }
233 
234   return CURLE_OK;
235 }
236 
237 
238 /***********************************************************************
239  *
240  * Curl_pp_sendf()
241  *
242  * Send the formatted string as a command to a pingpong server. Note that
243  * the string should not have any CRLF appended, as this function will
244  * append the necessary things itself.
245  *
246  * made to never block
247  */
Curl_pp_sendf(struct Curl_easy * data,struct pingpong * pp,const char * fmt,...)248 CURLcode Curl_pp_sendf(struct Curl_easy *data, struct pingpong *pp,
249                        const char *fmt, ...)
250 {
251   CURLcode result;
252   va_list ap;
253   va_start(ap, fmt);
254 
255   result = Curl_pp_vsendf(data, pp, fmt, ap);
256 
257   va_end(ap);
258 
259   return result;
260 }
261 
262 /*
263  * Curl_pp_readresp()
264  *
265  * Reads a piece of a server response.
266  */
Curl_pp_readresp(struct Curl_easy * data,curl_socket_t sockfd,struct pingpong * pp,int * code,size_t * size)267 CURLcode Curl_pp_readresp(struct Curl_easy *data,
268                           curl_socket_t sockfd,
269                           struct pingpong *pp,
270                           int *code, /* return the server code if done */
271                           size_t *size) /* size of the response */
272 {
273   ssize_t perline; /* count bytes per line */
274   bool keepon = TRUE;
275   ssize_t gotbytes;
276   char *ptr;
277   struct connectdata *conn = data->conn;
278   char * const buf = data->state.buffer;
279   CURLcode result = CURLE_OK;
280 
281   *code = 0; /* 0 for errors or not done */
282   *size = 0;
283 
284   ptr = buf + pp->nread_resp;
285 
286   /* number of bytes in the current line, so far */
287   perline = (ssize_t)(ptr-pp->linestart_resp);
288 
289   while((pp->nread_resp < (size_t)data->set.buffer_size) &&
290         (keepon && !result)) {
291 
292     if(pp->cache) {
293       /* we had data in the "cache", copy that instead of doing an actual
294        * read
295        *
296        * pp->cache_size is cast to ssize_t here.  This should be safe, because
297        * it would have been populated with something of size int to begin
298        * with, even though its datatype may be larger than an int.
299        */
300       if((ptr + pp->cache_size) > (buf + data->set.buffer_size + 1)) {
301         failf(data, "cached response data too big to handle");
302         return CURLE_RECV_ERROR;
303       }
304       memcpy(ptr, pp->cache, pp->cache_size);
305       gotbytes = (ssize_t)pp->cache_size;
306       free(pp->cache);    /* free the cache */
307       pp->cache = NULL;   /* clear the pointer */
308       pp->cache_size = 0; /* zero the size just in case */
309     }
310     else {
311 #ifdef HAVE_GSSAPI
312       enum protection_level prot = conn->data_prot;
313       conn->data_prot = PROT_CLEAR;
314 #endif
315       DEBUGASSERT((ptr + data->set.buffer_size - pp->nread_resp) <=
316                   (buf + data->set.buffer_size + 1));
317       result = Curl_read(data, sockfd, ptr,
318                          data->set.buffer_size - pp->nread_resp,
319                          &gotbytes);
320 #ifdef HAVE_GSSAPI
321       DEBUGASSERT(prot  > PROT_NONE && prot < PROT_LAST);
322       conn->data_prot = prot;
323 #endif
324       if(result == CURLE_AGAIN)
325         return CURLE_OK; /* return */
326 
327       if(!result && (gotbytes > 0))
328         /* convert from the network encoding */
329         result = Curl_convert_from_network(data, ptr, gotbytes);
330       /* Curl_convert_from_network calls failf if unsuccessful */
331 
332       if(result)
333         /* Set outer result variable to this error. */
334         keepon = FALSE;
335     }
336 
337     if(!keepon)
338       ;
339     else if(gotbytes <= 0) {
340       keepon = FALSE;
341       result = CURLE_RECV_ERROR;
342       failf(data, "response reading failed");
343     }
344     else {
345       /* we got a whole chunk of data, which can be anything from one
346        * byte to a set of lines and possible just a piece of the last
347        * line */
348       ssize_t i;
349       ssize_t clipamount = 0;
350       bool restart = FALSE;
351 
352       data->req.headerbytecount += (long)gotbytes;
353 
354       pp->nread_resp += gotbytes;
355       for(i = 0; i < gotbytes; ptr++, i++) {
356         perline++;
357         if(*ptr == '\n') {
358           /* a newline is CRLF in pp-talk, so the CR is ignored as
359              the line isn't really terminated until the LF comes */
360 
361           /* output debug output if that is requested */
362 #ifdef HAVE_GSSAPI
363           if(!conn->sec_complete)
364 #endif
365             Curl_debug(data, CURLINFO_HEADER_IN,
366                        pp->linestart_resp, (size_t)perline);
367 
368           /*
369            * We pass all response-lines to the callback function registered
370            * for "headers". The response lines can be seen as a kind of
371            * headers.
372            */
373           result = Curl_client_write(data, CLIENTWRITE_HEADER,
374                                      pp->linestart_resp, perline);
375           if(result)
376             return result;
377 
378           if(pp->endofresp(data, conn, pp->linestart_resp, perline, code)) {
379             /* This is the end of the last line, copy the last line to the
380                start of the buffer and null-terminate, for old times sake */
381             size_t n = ptr - pp->linestart_resp;
382             memmove(buf, pp->linestart_resp, n);
383             buf[n] = 0; /* null-terminate */
384             keepon = FALSE;
385             pp->linestart_resp = ptr + 1; /* advance pointer */
386             i++; /* skip this before getting out */
387 
388             *size = pp->nread_resp; /* size of the response */
389             pp->nread_resp = 0; /* restart */
390             break;
391           }
392           perline = 0; /* line starts over here */
393           pp->linestart_resp = ptr + 1;
394         }
395       }
396 
397       if(!keepon && (i != gotbytes)) {
398         /* We found the end of the response lines, but we didn't parse the
399            full chunk of data we have read from the server. We therefore need
400            to store the rest of the data to be checked on the next invoke as
401            it may actually contain another end of response already! */
402         clipamount = gotbytes - i;
403         restart = TRUE;
404         DEBUGF(infof(data, "Curl_pp_readresp_ %d bytes of trailing "
405                      "server response left",
406                      (int)clipamount));
407       }
408       else if(keepon) {
409 
410         if((perline == gotbytes) && (gotbytes > data->set.buffer_size/2)) {
411           /* We got an excessive line without newlines and we need to deal
412              with it. We keep the first bytes of the line then we throw
413              away the rest. */
414           infof(data, "Excessive server response line length received, "
415                 "%zd bytes. Stripping", gotbytes);
416           restart = TRUE;
417 
418           /* we keep 40 bytes since all our pingpong protocols are only
419              interested in the first piece */
420           clipamount = 40;
421         }
422         else if(pp->nread_resp > (size_t)data->set.buffer_size/2) {
423           /* We got a large chunk of data and there's potentially still
424              trailing data to take care of, so we put any such part in the
425              "cache", clear the buffer to make space and restart. */
426           clipamount = perline;
427           restart = TRUE;
428         }
429       }
430       else if(i == gotbytes)
431         restart = TRUE;
432 
433       if(clipamount) {
434         pp->cache_size = clipamount;
435         pp->cache = malloc(pp->cache_size);
436         if(pp->cache)
437           memcpy(pp->cache, pp->linestart_resp, pp->cache_size);
438         else
439           return CURLE_OUT_OF_MEMORY;
440       }
441       if(restart) {
442         /* now reset a few variables to start over nicely from the start of
443            the big buffer */
444         pp->nread_resp = 0; /* start over from scratch in the buffer */
445         ptr = pp->linestart_resp = buf;
446         perline = 0;
447       }
448 
449     } /* there was data */
450 
451   } /* while there's buffer left and loop is requested */
452 
453   pp->pending_resp = FALSE;
454 
455   return result;
456 }
457 
Curl_pp_getsock(struct Curl_easy * data,struct pingpong * pp,curl_socket_t * socks)458 int Curl_pp_getsock(struct Curl_easy *data,
459                     struct pingpong *pp, curl_socket_t *socks)
460 {
461   struct connectdata *conn = data->conn;
462   socks[0] = conn->sock[FIRSTSOCKET];
463 
464   if(pp->sendleft) {
465     /* write mode */
466     return GETSOCK_WRITESOCK(0);
467   }
468 
469   /* read mode */
470   return GETSOCK_READSOCK(0);
471 }
472 
Curl_pp_flushsend(struct Curl_easy * data,struct pingpong * pp)473 CURLcode Curl_pp_flushsend(struct Curl_easy *data,
474                            struct pingpong *pp)
475 {
476   /* we have a piece of a command still left to send */
477   struct connectdata *conn = data->conn;
478   ssize_t written;
479   curl_socket_t sock = conn->sock[FIRSTSOCKET];
480   CURLcode result = Curl_write(data, sock, pp->sendthis + pp->sendsize -
481                                pp->sendleft, pp->sendleft, &written);
482   if(result)
483     return result;
484 
485   if(written != (ssize_t)pp->sendleft) {
486     /* only a fraction was sent */
487     pp->sendleft -= written;
488   }
489   else {
490     pp->sendthis = NULL;
491     pp->sendleft = pp->sendsize = 0;
492     pp->response = Curl_now();
493   }
494   return CURLE_OK;
495 }
496 
Curl_pp_disconnect(struct pingpong * pp)497 CURLcode Curl_pp_disconnect(struct pingpong *pp)
498 {
499   Curl_dyn_free(&pp->sendbuf);
500   Curl_safefree(pp->cache);
501   return CURLE_OK;
502 }
503 
Curl_pp_moredata(struct pingpong * pp)504 bool Curl_pp_moredata(struct pingpong *pp)
505 {
506   return (!pp->sendleft && pp->cache && pp->nread_resp < pp->cache_size) ?
507     TRUE : FALSE;
508 }
509 
510 #endif
511