05_dccp-supported-ccid-lookup.diff
[paraslash.git] / net.c
1 /*
2 * Copyright (C) 2005-2009 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file net.c Networking-related helper functions. */
8
9 /*
10 * Since glibc 2.8, the _GNU_SOURCE feature test macro must be defined in order
11 * to obtain the definition of the ucred structure.
12 */
13 #define _GNU_SOURCE
14
15 #include <netdb.h>
16
17 /* At least NetBSD needs these. */
18 #ifndef AI_V4MAPPED
19 #define AI_V4MAPPED 0
20 #endif
21 #ifndef AI_ALL
22 #define AI_ALL 0
23 #endif
24 #ifndef AI_ADDRCONFIG
25 #define AI_ADDRCONFIG 0
26 #endif
27
28 #include <dirent.h>
29 #include <regex.h>
30 #include <openssl/rc4.h>
31
32 #include "para.h"
33 #include "error.h"
34 #include "crypt.h"
35 #include "net.h"
36 #include "string.h"
37 #include "fd.h"
38
39 /**
40 * Parse and validate IPv4 address/netmask string.
41 *
42 * \param cidr Address in CIDR notation
43 * \param addr Copy of the IPv4 address part of \a cidr
44 * \param addrlen Size of \a addr in bytes
45 * \param netmask Value of the netmask part in \a cidr or the
46 * default of 32 if not specified.
47 *
48 * \return Pointer to \a addr if succesful, NULL on error.
49 * \sa RFC 4632
50 */
51 char *parse_cidr(const char *cidr,
52 char *addr, ssize_t addrlen,
53 int32_t *netmask)
54 {
55 const char *o = cidr;
56 char *c = addr, *end = c + (addrlen - 1);
57
58 *netmask = 0x20;
59
60 if (cidr == NULL || addrlen < 1)
61 goto failed;
62
63 for (o = cidr; (*c = *o == '/'? '\0' : *o); c++, o++)
64 if (c == end)
65 goto failed;
66
67 if (*o == '/')
68 if (para_atoi32(++o, netmask) < 0 ||
69 *netmask < 0 || *netmask > 0x20)
70 goto failed;
71
72 if (is_valid_ipv4_address(addr))
73 return addr;
74 failed:
75 *addr = '\0';
76 return NULL;
77 }
78
79
80 /**
81 * Match string as a candidate IPv4 address.
82 *
83 * \param address The string to match.
84 * \return True if \a address has "dot-quad" format.
85 */
86 static bool is_v4_dot_quad(const char *address)
87 {
88 bool result;
89 regex_t r;
90
91 assert(para_regcomp(&r, "^([0-9]+\\.){3}[0-9]+$",
92 REG_EXTENDED | REG_NOSUB) >= 0);
93 result = regexec(&r, address, 0, NULL, 0) == 0;
94 regfree(&r);
95 return result;
96 }
97
98 /**
99 * Perform basic syntax checking on the host-part of an URL:
100 *
101 * - Since ':' is invalid in IPv4 addresses and DNS names, the
102 * presence of ':' causes interpretation as IPv6 address;
103 * - next the first-match-wins algorithm from RFC 3986 is applied;
104 * - else the string is considered as DNS name, to be resolved later.
105 *
106 * \param host The host string to check.
107 * \return True if \a host passes the syntax checks.
108 *
109 * \sa RFC 3986, 3.2.2; RFC 1123, 2.1; RFC 1034, 3.5
110 */
111 static bool host_string_ok(const char *host)
112 {
113 if (host == NULL || *host == '\0')
114 return false;
115 if (strchr(host, ':') != NULL)
116 return is_valid_ipv6_address(host);
117 if (is_v4_dot_quad(host))
118 return is_valid_ipv4_address(host);
119 return true;
120 }
121
122 /**
123 * Parse and validate URL string.
124 *
125 * The URL syntax is loosely based on RFC 3986, supporting one of
126 * - "["host"]"[:port] for native IPv6 addresses and
127 * - host[:port] for IPv4 hostnames and DNS names.
128 *
129 * Native IPv6 addresses must be enclosed in square brackets, since
130 * otherwise there is an ambiguity with the port separator `:'.
131 * The 'port' part is always considered to be a number; if absent,
132 * it is set to -1, to indicate that a default port is to be used.
133 *
134 * The following are valid examples:
135 * - 10.10.1.1
136 * - 10.10.1.2:8000
137 * - localhost
138 * - localhost:8001
139 * - [::1]:8000
140 * - [badc0de::1]
141 *
142 * \param url The URL string to take apart.
143 * \param host To return the copied host part of \a url.
144 * \param hostlen The maximum length of \a host.
145 * \param port To return the port number (if any) of \a url.
146 *
147 * \return Pointer to \a host, or NULL if failed.
148 * If NULL is returned, \a host and \a portnum are undefined. If no
149 * port number was present in \a url, \a portnum is set to -1.
150 *
151 * \sa RFC 3986, 3.2.2/3.2.3
152 */
153 char *parse_url(const char *url,
154 char *host, ssize_t hostlen,
155 int32_t *port)
156 {
157 const char *o = url;
158 char *c = host, *end = c + (hostlen - 1);
159
160 *port = -1;
161
162 if (o == NULL || hostlen < 1)
163 goto failed;
164
165 if (*o == '[') {
166 for (++o; (*c = *o == ']' ? '\0' : *o); c++, o++)
167 if (c == end)
168 goto failed;
169
170 if (*o++ != ']' || (*o != '\0' && *o != ':'))
171 goto failed;
172 } else {
173 for (; (*c = *o == ':'? '\0' : *o); c++, o++)
174 if (c == end)
175 goto failed;
176 }
177
178 if (*o == ':')
179 if (para_atoi32(++o, port) < 0 ||
180 *port < 0 || *port > 0xffff)
181 goto failed;
182
183 if (host_string_ok(host))
184 return host;
185 failed:
186 *host = '\0';
187 return NULL;
188 }
189
190 /**
191 * Stringify port number, resolve into service name where defined.
192 * \param port 2-byte port number, in host-byte-order.
193 * \param transport Transport protocol name (e.g. "udp", "tcp"), or NULL.
194 * \return Pointer to static result buffer.
195 *
196 * \sa getservent(3), services(5), nsswitch.conf(5)
197 */
198 const char *stringify_port(int port, const char *transport)
199 {
200 static char service[NI_MAXSERV];
201
202 if (port < 0 || port > 0xFFFF) {
203 snprintf(service, sizeof(service), "undefined (%d)", port);
204 } else {
205 struct servent *se = getservbyport(htons(port), transport);
206
207 if (se == NULL)
208 snprintf(service, sizeof(service), "%u", port);
209 else
210 snprintf(service, sizeof(service), "%s", se->s_name);
211 }
212 return service;
213 }
214
215 /**
216 * Determine the socket type for a given layer-4 protocol.
217 *
218 * \param l4type The symbolic name of the transport-layer protocol.
219 *
220 * \sa ip(7), socket(2)
221 */
222 static inline int sock_type(const unsigned l4type)
223 {
224 switch (l4type) {
225 case IPPROTO_UDP: return SOCK_DGRAM;
226 case IPPROTO_TCP: return SOCK_STREAM;
227 case IPPROTO_DCCP: return SOCK_DCCP;
228 }
229 return -1; /* not supported here */
230 }
231
232 /**
233 * Pretty-print transport-layer name.
234 */
235 static const char *layer4_name(const unsigned l4type)
236 {
237 switch (l4type) {
238 case IPPROTO_UDP: return "UDP";
239 case IPPROTO_TCP: return "TCP";
240 case IPPROTO_DCCP: return "DCCP";
241 }
242 return "UNKNOWN PROTOCOL";
243 }
244
245 /**
246 * Resolve IPv4/IPv6 address and create a ready-to-use active or passive socket.
247 *
248 * \param l3type The layer-3 type (\p AF_INET, \p AF_INET6, \p AF_UNSPEC).
249 * \param l4type The layer-4 type (\p IPPROTO_xxx).
250 * \param passive Whether this is a passive (1) or active (0) socket.
251 * \param host Remote or local hostname or IPv/6 address string.
252 * \param port_number Decimal port number.
253 *
254 * This creates a ready-made IPv4/v6 socket structure after looking up the
255 * necessary parameters. The interpretation of \a host depends on the value of
256 * \a passive:
257 * - on a passive socket host is interpreted as an interface IPv4/6 address
258 * (can be left NULL);
259 * - on an active socket, \a host is the peer DNS name or IPv4/6 address
260 * to connect to;
261 * - \a port_number is in either case the numeric port number (not service
262 * string).
263 *
264 * Furthermore, bind(2) is called on passive sockets, and connect(2) on active
265 * sockets. The algorithm tries all possible address combinations until it
266 * succeeds.
267 *
268 * \return This function returns 1 on success and \a -E_ADDRESS_LOOKUP when no
269 * matching connection could be set up (with details in the error log).
270 *
271 * \sa ipv6(7), getaddrinfo(3), bind(2), connect(2).
272 */
273 int makesock(unsigned l3type, unsigned l4type, int passive,
274 const char *host, unsigned short port_number)
275 {
276 struct addrinfo *local = NULL, *src,
277 *remote = NULL, *dst, hints;
278 int rc, on = 1, sockfd = -1,
279 socktype = sock_type(l4type);
280 char port[6]; /* port number has at most 5 digits */
281
282 sprintf(port, "%u", port_number);
283 /* Set up address hint structure */
284 memset(&hints, 0, sizeof(hints));
285 hints.ai_family = l3type;
286 hints.ai_socktype = socktype;
287 /*
288 * getaddrinfo does not support SOCK_DCCP, so for the sake of lookup
289 * (and only then) pretend to be UDP.
290 */
291 if (l4type == IPPROTO_DCCP)
292 hints.ai_socktype = SOCK_DGRAM;
293
294 /* only use addresses available on the host */
295 hints.ai_flags = AI_ADDRCONFIG;
296 if (l3type == AF_INET6)
297 /* use v4-mapped-v6 if no v6 addresses found */
298 hints.ai_flags |= AI_V4MAPPED | AI_ALL;
299
300 if (passive && host == NULL)
301 hints.ai_flags |= AI_PASSIVE;
302
303 /* Obtain local/remote address information */
304 if ((rc = getaddrinfo(host, port, &hints, passive ? &local : &remote))) {
305 PARA_ERROR_LOG("can not resolve %s address %s#%s: %s.\n",
306 layer4_name(l4type),
307 host? host : (passive? "[loopback]" : "[localhost]"),
308 port, gai_strerror(rc));
309 return -E_ADDRESS_LOOKUP;
310 }
311
312 /* Iterate over all src/dst combination, exhausting dst first */
313 for (src = local, dst = remote; src != NULL || dst != NULL; /* no op */ ) {
314 if (src && dst && src->ai_family == AF_INET
315 && dst->ai_family == AF_INET6)
316 goto get_next_dst; /* v4 -> v6 is not possible */
317
318 sockfd = socket(src ? src->ai_family : dst->ai_family,
319 socktype, l4type);
320 if (sockfd < 0)
321 goto get_next_dst;
322
323 /*
324 * Set those options that need to be set before establishing
325 * the connection. Reuse the address on passive (listening)
326 * sockets to avoid failure on restart.
327 */
328 if (passive && setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
329 &on, sizeof(on)) == -1) {
330 PARA_ERROR_LOG("can not set SO_REUSEADDR: %s\n",
331 strerror(errno));
332 return -ERRNO_TO_PARA_ERROR(errno);
333 }
334
335 if (src) {
336 if (bind(sockfd, src->ai_addr, src->ai_addrlen) < 0) {
337 close(sockfd);
338 goto get_next_src;
339 }
340 if (!dst) /* bind-only completed successfully */
341 break;
342 }
343
344 if (dst && connect(sockfd, dst->ai_addr, dst->ai_addrlen) == 0)
345 break; /* connection completed successfully */
346 close(sockfd);
347 get_next_dst:
348 if (dst && (dst = dst->ai_next))
349 continue;
350 get_next_src:
351 if (src && (src = src->ai_next)) /* restart inner loop */
352 dst = remote;
353 }
354 if (local)
355 freeaddrinfo(local);
356 if (remote)
357 freeaddrinfo(remote);
358
359 if (src == NULL && dst == NULL) {
360 PARA_ERROR_LOG("can not create %s socket %s#%s.\n",
361 layer4_name(l4type), host? host : (passive?
362 "[loopback]" : "[localhost]"), port);
363 return -ERRNO_TO_PARA_ERROR(errno);
364 }
365 return sockfd;
366 }
367
368 /**
369 * Create a passive / listening socket.
370 *
371 * \param l3type The network-layer type (\p AF_xxx).
372 * \param l4type The transport-layer type (\p IPPROTO_xxx).
373 * \param port The decimal port number to listen on.
374 *
375 * \return Positive integer (socket descriptor) on success, negative value
376 * otherwise.
377 *
378 * \sa makesock(), ip(7), ipv6(7), bind(2), listen(2).
379 */
380 int para_listen(unsigned l3type, unsigned l4type, unsigned short port)
381 {
382 int ret, fd = makesock(l3type, l4type, 1, NULL, port);
383
384 if (fd > 0) {
385 ret = listen(fd, BACKLOG);
386 if (ret < 0) {
387 close(fd);
388 return -ERRNO_TO_PARA_ERROR(errno);
389 }
390 PARA_INFO_LOG("listening on %s port %u, fd %d\n",
391 layer4_name(l4type), port, fd);
392 }
393 return fd;
394 }
395
396 /**
397 * Determine IPv4/v6 socket address length.
398 * \param sa Container of IPv4 or IPv6 address.
399 * \return Address-family dependent address length.
400 */
401 static socklen_t salen(const struct sockaddr *sa)
402 {
403 assert(sa->sa_family == AF_INET || sa->sa_family == AF_INET6);
404
405 return sa->sa_family == AF_INET6
406 ? sizeof(struct sockaddr_in6)
407 : sizeof(struct sockaddr_in);
408 }
409
410 /**
411 * Process IPv4/v6 address, turn v6-mapped-v4 address into normal IPv4 address.
412 * \param ss Container of IPv4/6 address.
413 * \return Pointer to normalized address (may be static storage).
414 *
415 * \sa RFC 3493
416 */
417 static const struct sockaddr *
418 normalize_ip_address(const struct sockaddr_storage *ss)
419 {
420 const struct sockaddr_in6 *ia6 = (const struct sockaddr_in6 *)ss;
421
422 assert(ss->ss_family == AF_INET || ss->ss_family == AF_INET6);
423
424 if (ss->ss_family == AF_INET6 && IN6_IS_ADDR_V4MAPPED(&ia6->sin6_addr)) {
425 static struct sockaddr_in ia;
426
427 ia.sin_family = AF_INET;
428 ia.sin_port = ia6->sin6_port;
429 memcpy(&ia.sin_addr.s_addr, &(ia6->sin6_addr.s6_addr[12]), 4);
430 return (const struct sockaddr *)&ia;
431 }
432 return (const struct sockaddr *)ss;
433 }
434
435 /**
436 * Print numeric host and port number (beware - uses static char).
437 *
438 * \param sa The IPv4/IPv6 socket address to use.
439 *
440 * \sa getnameinfo(3), services(5), nsswitch.conf(5)
441 */
442 static char *host_and_port(const struct sockaddr_storage *ss)
443 {
444 const struct sockaddr *sa = normalize_ip_address(ss);
445 char hbuf[NI_MAXHOST], sbuf[NI_MAXSERV];
446 static char output[sizeof(hbuf) + sizeof(sbuf) + 2];
447 int ret;
448
449 ret = getnameinfo(sa, salen(sa),
450 hbuf, sizeof(hbuf),
451 sbuf, sizeof(sbuf),
452 NI_NUMERICHOST);
453 if (ret == 0) {
454 snprintf(output, sizeof(output), "%s#%s", hbuf, sbuf);
455 } else {
456 snprintf(output, sizeof(output), "(unknown)");
457 PARA_WARNING_LOG("hostname lookup error (%s).\n",
458 gai_strerror(ret));
459 }
460 return output;
461 }
462
463 /**
464 * Look up the local or remote side of a connected socket structure.
465 *
466 * \param fd The socket descriptor of the connected socket.
467 * \param getname Either \p getsockname() for local, or \p getpeername() for
468 * remote side.
469 *
470 * \return A static character string identifying hostname and port of the
471 * chosen side.
472 *
473 * \sa getsockname(2), getpeername(2).
474 */
475 static char *__get_sock_name(int fd, int (*getname)(int, struct sockaddr*,
476 socklen_t *))
477 {
478 struct sockaddr_storage ss;
479 socklen_t sslen = sizeof(ss);
480
481 if (getname(fd, (struct sockaddr *)&ss, &sslen) < 0) {
482 static char *dont_know = "(don't know)";
483 PARA_ERROR_LOG("can not determine address from fd %d: %s\n",
484 fd, strerror(errno));
485 return dont_know;
486 }
487 return host_and_port(&ss);
488 }
489
490 /**
491 * Look up the local side of a connected socket structure.
492 *
493 * \param sockfd The file descriptor of the socket.
494 *
495 * \return A pointer to a static buffer containing hostname an port. This
496 * buffer must not be freed by the caller.
497 *
498 * \sa remote_name().
499 */
500 char *local_name(int sockfd)
501 {
502 return __get_sock_name(sockfd, getsockname);
503 }
504
505 /**
506 * Look up the remote side of a connected socket structure.
507 *
508 * \param sockfd The file descriptor of the socket.
509 *
510 * \return Analogous to the return value of \ref local_name() but for the
511 * remote side.
512 *
513 * \sa local_name().
514 */
515 char *remote_name(int sockfd)
516 {
517 return __get_sock_name(sockfd, getpeername);
518 }
519
520 /**
521 * Extract IPv4 or IPv6-mapped-IPv4 address from sockaddr_storage.
522 * \param ss Container of IPv4/6 address
523 * \return Extracted IPv4 address (different from 0) or 0 if unsuccessful.
524 *
525 * \sa RFC 3493
526 */
527 struct in_addr extract_v4_addr(const struct sockaddr_storage *ss)
528 {
529 struct in_addr ia = {.s_addr = 0};
530 const struct sockaddr *sa = normalize_ip_address(ss);
531
532 if (sa->sa_family == AF_INET)
533 ia = ((struct sockaddr_in *)sa)->sin_addr;
534 return ia;
535 }
536
537 /**
538 * Send a binary buffer.
539 *
540 * \param fd The file descriptor.
541 * \param buf The buffer to be sent.
542 * \param len The length of \a buf.
543 *
544 * Send out the buffer and try to resend the remaining part in case of short
545 * writes.
546 *
547 * \return Standard.
548 */
549 int send_bin_buffer(int fd, const char *buf, size_t len)
550 {
551 if (!len)
552 PARA_CRIT_LOG("len == 0\n");
553 return write_all(fd, buf, &len);
554 }
555
556 /**
557 * Send a \p NULL-terminated buffer.
558 *
559 * \param fd The file descriptor.
560 * \param buf The null-terminated buffer to be send.
561 *
562 * This is equivalent to send_bin_buffer(fd, buf, strlen(buf)).
563 *
564 * \return Standard.
565 */
566 int send_buffer(int fd, const char *buf)
567 {
568 return send_bin_buffer(fd, buf, strlen(buf));
569 }
570
571 /**
572 * Send a buffer given by a format string.
573 *
574 * \param fd The file descriptor.
575 * \param fmt A format string.
576 *
577 * \return Standard.
578 */
579 __printf_2_3 int send_va_buffer(int fd, const char *fmt, ...)
580 {
581 char *msg;
582 int ret;
583
584 PARA_VSPRINTF(fmt, msg);
585 ret = send_buffer(fd, msg);
586 free(msg);
587 return ret;
588 }
589
590 /**
591 * Receive data from a file descriptor.
592 *
593 * \param fd The file descriptor.
594 * \param buf The buffer to write the data to.
595 * \param size The size of \a buf.
596 *
597 * Receive at most \a size bytes from file descriptor \a fd.
598 *
599 * \return The number of bytes received on success, negative on errors, zero if
600 * the peer has performed an orderly shutdown.
601 *
602 * \sa recv(2).
603 */
604 __must_check int recv_bin_buffer(int fd, char *buf, size_t size)
605 {
606 ssize_t n;
607
608 n = recv(fd, buf, size, 0);
609 if (n == -1)
610 return -ERRNO_TO_PARA_ERROR(errno);
611 return n;
612 }
613
614 /**
615 * Receive and write terminating NULL byte.
616 *
617 * \param fd The file descriptor.
618 * \param buf The buffer to write the data to.
619 * \param size The size of \a buf.
620 *
621 * Read at most \a size - 1 bytes from file descriptor \a fd and
622 * write a NULL byte at the end of the received data.
623 *
624 * \return The return value of the underlying call to \a recv_bin_buffer().
625 *
626 * \sa recv_bin_buffer()
627 */
628 int recv_buffer(int fd, char *buf, size_t size)
629 {
630 int n;
631
632 assert(size);
633 n = recv_bin_buffer(fd, buf, size - 1);
634 if (n >= 0)
635 buf[n] = '\0';
636 else
637 *buf = '\0';
638 return n;
639 }
640
641 /**
642 * Wrapper around the accept system call.
643 *
644 * \param fd The listening socket.
645 * \param addr Structure which is filled in with the address of the peer socket.
646 * \param size Should contain the size of the structure pointed to by \a addr.
647 *
648 * Accept incoming connections on \a addr. Retry if interrupted.
649 *
650 * \return The new file descriptor on success, negative on errors.
651 *
652 * \sa accept(2).
653 */
654 int para_accept(int fd, void *addr, socklen_t size)
655 {
656 int new_fd;
657
658 do
659 new_fd = accept(fd, (struct sockaddr *) addr, &size);
660 while (new_fd < 0 && errno == EINTR);
661 return new_fd < 0? -ERRNO_TO_PARA_ERROR(errno) : new_fd;
662 }
663
664 /**
665 * Probe the list of DCCP CCIDs supported locally by the host.
666 * \param ccids Array to be filled in.
667 * \param nccids Length of \a ccids.
668 * \return Pointer to \a ccids, NULL on failure.
669 *
670 * NB: This feature is only available on Linux > 2.6.30; on older kernels
671 * ENOPROTOOPT ("Protocol not available") will be returned.
672 */
673 const uint8_t *dccp_available_ccids(uint8_t *ccids, uint8_t *nccids)
674 {
675 int fd = makesock(AF_UNSPEC, IPPROTO_DCCP, 0, NULL, 0);
676
677 if (fd < 0)
678 return NULL;
679
680 if (getsockopt(fd, SOL_DCCP, DCCP_SOCKOPT_AVAILABLE_CCIDS,
681 ccids, (socklen_t *)nccids) < 0) {
682 PARA_ERROR_LOG("No DCCP_SOCKOPT_AVAILABLE_CCIDS: %s\n",
683 strerror(errno));
684 *nccids = 0;
685 }
686 close(fd);
687
688 return *nccids ? ccids : NULL;
689 }
690
691 /**
692 * Prepare a structure for \p AF_UNIX socket addresses.
693 *
694 * \param u Pointer to the struct to be prepared.
695 * \param name The socket pathname.
696 *
697 * This just copies \a name to the sun_path component of \a u.
698 *
699 * \return Positive on success, \p -E_NAME_TOO_LONG if \a name is longer
700 * than \p UNIX_PATH_MAX.
701 */
702 static int init_unix_addr(struct sockaddr_un *u, const char *name)
703 {
704 if (strlen(name) >= UNIX_PATH_MAX)
705 return -E_NAME_TOO_LONG;
706 memset(u->sun_path, 0, UNIX_PATH_MAX);
707 u->sun_family = PF_UNIX;
708 strcpy(u->sun_path, name);
709 return 1;
710 }
711
712 /**
713 * Prepare, create, and bind a socket for local communication.
714 *
715 * \param name The socket pathname.
716 * \param unix_addr Pointer to the \p AF_UNIX socket structure.
717 * \param mode The desired mode of the socket.
718 *
719 * This function creates a local socket for sequenced, reliable,
720 * two-way, connection-based byte streams.
721 *
722 * \return The file descriptor, on success, negative on errors.
723 *
724 * \sa socket(2)
725 * \sa bind(2)
726 * \sa chmod(2)
727 */
728 int create_local_socket(const char *name, struct sockaddr_un *unix_addr,
729 mode_t mode)
730 {
731 int fd, ret;
732
733 ret = init_unix_addr(unix_addr, name);
734 if (ret < 0)
735 return ret;
736 ret = socket(PF_UNIX, SOCK_STREAM, 0);
737 if (ret < 0)
738 return -ERRNO_TO_PARA_ERROR(errno);
739 fd = ret;
740 ret = bind(fd, (struct sockaddr *) unix_addr, UNIX_PATH_MAX);
741 if (ret < 0) {
742 ret = -ERRNO_TO_PARA_ERROR(errno);
743 goto err;
744 }
745 ret = -E_CHMOD;
746 if (chmod(name, mode) < 0)
747 goto err;
748 return fd;
749 err:
750 close(fd);
751 return ret;
752 }
753
754 /**
755 * Prepare, create, and connect to a Unix domain socket for local communication.
756 *
757 * \param name The socket pathname.
758 *
759 * This function creates a local socket for sequenced, reliable, two-way,
760 * connection-based byte streams.
761 *
762 * \return The file descriptor, on success, negative on errors.
763 *
764 * \sa create_local_socket(), unix(7), connect(2).
765 */
766 int create_remote_socket(const char *name)
767 {
768 struct sockaddr_un unix_addr;
769 int fd, ret;
770
771 ret = init_unix_addr(&unix_addr, name);
772 if (ret < 0)
773 return ret;
774 fd = socket(PF_UNIX, SOCK_STREAM, 0);
775 if (fd < 0)
776 return -ERRNO_TO_PARA_ERROR(errno);
777 if (connect(fd, (struct sockaddr *)&unix_addr, sizeof(unix_addr)) == -1) {
778 ret = -ERRNO_TO_PARA_ERROR(errno);
779 goto err;
780 }
781 return fd;
782 err:
783 close(fd);
784 return ret;
785 }
786
787 #ifndef HAVE_UCRED
788 ssize_t send_cred_buffer(int sock, char *buf)
789 {
790 return send_buffer(sock, buf);
791 }
792 int recv_cred_buffer(int fd, char *buf, size_t size)
793 {
794 return recv_buffer(fd, buf, size) > 0? 1 : -E_RECVMSG;
795 }
796 #else /* HAVE_UCRED */
797 /**
798 * Send \p NULL-terminated buffer and Unix credentials of the current process.
799 *
800 * \param sock The socket file descriptor.
801 * \param buf The buffer to be sent.
802 *
803 * \return On success, this call returns the number of characters sent. On
804 * error, \p -E_SENDMSG is returned.
805 *
806 * \sa sendmsg(2), okir's Black Hats Manual.
807 */
808 ssize_t send_cred_buffer(int sock, char *buf)
809 {
810 char control[sizeof(struct cmsghdr) + sizeof(struct ucred)];
811 struct msghdr msg;
812 struct cmsghdr *cmsg;
813 static struct iovec iov;
814 struct ucred c;
815 int ret;
816
817 /* Response data */
818 iov.iov_base = buf;
819 iov.iov_len = strlen(buf);
820 c.pid = getpid();
821 c.uid = getuid();
822 c.gid = getgid();
823 /* compose the message */
824 memset(&msg, 0, sizeof(msg));
825 msg.msg_iov = &iov;
826 msg.msg_iovlen = 1;
827 msg.msg_control = control;
828 msg.msg_controllen = sizeof(control);
829 /* attach the ucred struct */
830 cmsg = CMSG_FIRSTHDR(&msg);
831 cmsg->cmsg_level = SOL_SOCKET;
832 cmsg->cmsg_type = SCM_CREDENTIALS;
833 cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred));
834 *(struct ucred *)CMSG_DATA(cmsg) = c;
835 msg.msg_controllen = cmsg->cmsg_len;
836 ret = sendmsg(sock, &msg, 0);
837 if (ret < 0)
838 ret = -E_SENDMSG;
839 return ret;
840 }
841
842 static void dispose_fds(int *fds, unsigned num)
843 {
844 int i;
845
846 for (i = 0; i < num; i++)
847 close(fds[i]);
848 }
849
850 /**
851 * Receive a buffer and the Unix credentials of the sending process.
852 *
853 * \param fd the socket file descriptor.
854 * \param buf the buffer to store the message.
855 * \param size the size of \a buffer.
856 *
857 * \return negative on errors, the user id on success.
858 *
859 * \sa recvmsg(2), okir's Black Hats Manual.
860 */
861 int recv_cred_buffer(int fd, char *buf, size_t size)
862 {
863 char control[255];
864 struct msghdr msg;
865 struct cmsghdr *cmsg;
866 struct iovec iov;
867 int result = 0;
868 int yes = 1;
869 struct ucred cred;
870
871 setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &yes, sizeof(int));
872 memset(&msg, 0, sizeof(msg));
873 memset(buf, 0, size);
874 iov.iov_base = buf;
875 iov.iov_len = size;
876 msg.msg_iov = &iov;
877 msg.msg_iovlen = 1;
878 msg.msg_control = control;
879 msg.msg_controllen = sizeof(control);
880 if (recvmsg(fd, &msg, 0) < 0)
881 return -E_RECVMSG;
882 result = -E_SCM_CREDENTIALS;
883 cmsg = CMSG_FIRSTHDR(&msg);
884 while (cmsg) {
885 if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type
886 == SCM_CREDENTIALS) {
887 memcpy(&cred, CMSG_DATA(cmsg), sizeof(struct ucred));
888 result = cred.uid;
889 } else
890 if (cmsg->cmsg_level == SOL_SOCKET
891 && cmsg->cmsg_type == SCM_RIGHTS) {
892 dispose_fds((int *) CMSG_DATA(cmsg),
893 (cmsg->cmsg_len - CMSG_LEN(0))
894 / sizeof(int));
895 }
896 cmsg = CMSG_NXTHDR(&msg, cmsg);
897 }
898 return result;
899 }
900 #endif /* HAVE_UCRED */
901
902 /**
903 * Receive a buffer and check for a pattern.
904 *
905 * \param fd The file descriptor to receive from.
906 * \param pattern The expected pattern.
907 * \param bufsize The size of the internal buffer.
908 *
909 * \return Positive if \a pattern was received, negative otherwise.
910 *
911 * This function tries to receive at most \a bufsize bytes from file descriptor
912 * \a fd. If at least \p strlen(\a pattern) bytes were received, the beginning
913 * of the received buffer is compared with \a pattern, ignoring case.
914 *
915 * \sa recv_buffer(), \sa strncasecmp(3).
916 */
917 int recv_pattern(int fd, const char *pattern, size_t bufsize)
918 {
919 size_t len = strlen(pattern);
920 char *buf = para_malloc(bufsize + 1);
921 int ret = -E_RECV_PATTERN, n = recv_buffer(fd, buf, bufsize + 1);
922
923 if (n < len)
924 goto out;
925 if (strncasecmp(buf, pattern, len))
926 goto out;
927 ret = 1;
928 out:
929 if (ret < 0) {
930 PARA_NOTICE_LOG("did not receive pattern '%s'\n", pattern);
931 if (n > 0)
932 PARA_NOTICE_LOG("recvd %d bytes: %s\n", n, buf);
933 else if (n < 0)
934 PARA_NOTICE_LOG("%s\n", para_strerror(-n));
935 }
936 free(buf);
937 return ret;
938 }