2 * Copyright (C) 2005-2008 Andre Noll <maan@systemlinux.org>
4 * Licensed under the GPL v2. For licencing details see COPYING.
7 /** \file net.c Networking-related helper functions. */
11 /* At least NetBSD needs these. */
19 #define AI_ADDRCONFIG 0
29 /** Information about one encrypted connection. */
31 /** Function used to decrypt received data. */
33 /** Function used to encrypt data to be sent. */
36 * Context-dependent data (crypt keys), passed verbatim to the above
41 /** Array holding per fd crypt data. */
42 static struct crypt_data *crypt_data_array;
43 /** Current size of the crypt data array. */
44 static unsigned cda_size = 0;
47 * Activate encryption for one file descriptor.
49 * \param fd The file descriptor.
50 * \param recv_f The function used for decrypting received data.
51 * \param send_f The function used for encrypting before sending.
52 * \param private_data User data supplied by the caller.
54 void enable_crypt(int fd, crypt_function *recv_f, crypt_function *send_f,
57 if (fd + 1 > cda_size) {
58 crypt_data_array = para_realloc(crypt_data_array,
59 (fd + 1) * sizeof(struct crypt_data));
60 memset(crypt_data_array + cda_size, 0,
61 (fd + 1 - cda_size) * sizeof(struct crypt_data));
64 crypt_data_array[fd].recv = recv_f;
65 crypt_data_array[fd].send = send_f;
66 crypt_data_array[fd].private_data = private_data;
67 PARA_INFO_LOG("rc4 encryption activated for fd %d\n", fd);
71 * Deactivate encryption for a given fd.
73 * \param fd The file descriptor.
75 * This must be called if and only if \p fd was activated via enable_crypt().
77 void disable_crypt(int fd)
79 if (cda_size < fd + 1)
81 crypt_data_array[fd].recv = NULL;
82 crypt_data_array[fd].send = NULL;
83 crypt_data_array[fd].private_data = NULL;
88 * Determine the socket type for a given layer-4 protocol.
90 * \param l4type The symbolic name of the transport-layer protocol.
92 * \sa ip(7), socket(2)
94 static inline int sock_type(const unsigned l4type)
97 case IPPROTO_UDP: return SOCK_DGRAM;
98 case IPPROTO_TCP: return SOCK_STREAM;
99 case IPPROTO_DCCP: return SOCK_DCCP;
101 return -1; /* not supported here */
105 * Pretty-print transport-layer name.
107 static const char *layer4_name(const unsigned l4type)
110 case IPPROTO_UDP: return "UDP";
111 case IPPROTO_TCP: return "TCP";
112 case IPPROTO_DCCP: return "DCCP";
114 return "UNKNOWN PROTOCOL";
118 * Resolve IPv4/IPv6 address and create a ready-to-use active or passive socket.
120 * \param l3type The layer-3 type (\p AF_INET, \p AF_INET6, \p AF_UNSPEC).
121 * \param l4type The layer-4 type (\p IPPROTO_xxx).
122 * \param passive Whether this is a passive (1) or active (0) socket.
123 * \param host Remote or local hostname or IPv/6 address string.
124 * \param port_number Decimal port number.
126 * This creates a ready-made IPv4/v6 socket structure after looking up the
127 * necessary parameters. The interpretation of \a host depends on the value of
129 * - on a passive socket host is interpreted as an interface IPv4/6 address
130 * (can be left NULL);
131 * - on an active socket, \a host is the peer DNS name or IPv4/6 address
133 * - \a port_number is in either case the numeric port number (not service
136 * Furthermore, bind(2) is called on passive sockets, and connect(2) on active
137 * sockets. The algorithm tries all possible address combinations until it
140 * \return This function returns 1 on success and \a -E_ADDRESS_LOOKUP when no
141 * matching connection could be set up (with details in the error log).
143 * \sa ipv6(7), getaddrinfo(3), bind(2), connect(2).
145 int makesock(unsigned l3type, unsigned l4type, int passive,
146 const char *host, unsigned short port_number)
148 struct addrinfo *local = NULL, *src,
149 *remote = NULL, *dst, hints;
150 int rc, on = 1, sockfd = -1,
151 socktype = sock_type(l4type);
152 char port[6]; /* port number has at most 5 digits */
154 sprintf(port, "%u", port_number);
155 /* Set up address hint structure */
156 memset(&hints, 0, sizeof(hints));
157 hints.ai_family = l3type;
158 /* getaddrinfo does not really work well with SOCK_DCCP */
159 if (socktype == SOCK_DGRAM || socktype == SOCK_STREAM)
160 hints.ai_socktype = socktype;
162 /* only use addresses available on the host */
163 hints.ai_flags = AI_ADDRCONFIG;
164 if (l3type == AF_INET6)
165 /* use v4-mapped-v6 if no v6 addresses found */
166 hints.ai_flags |= AI_V4MAPPED | AI_ALL;
168 if (passive && host == NULL)
169 hints.ai_flags |= AI_PASSIVE;
171 /* Obtain local/remote address information */
172 if ((rc = getaddrinfo(host, port, &hints, passive ? &local : &remote))) {
173 PARA_ERROR_LOG("can not resolve %s address %s#%s: %s.\n",
175 host? host : (passive? "[loopback]" : "[localhost]"),
176 port, gai_strerror(rc));
177 return -E_ADDRESS_LOOKUP;
180 /* Iterate over all src/dst combination, exhausting dst first */
181 for (src = local, dst = remote; src != NULL || dst != NULL; /* no op */ ) {
182 if (src && dst && src->ai_family == AF_INET
183 && dst->ai_family == AF_INET6)
184 goto get_next_dst; /* v4 -> v6 is not possible */
186 sockfd = socket(src ? src->ai_family : dst->ai_family,
192 * Set those options that need to be set before establishing
193 * the connection. Reuse the address on passive (listening)
194 * sockets to avoid failure on restart.
196 if (passive && setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
197 &on, sizeof(on)) == -1) {
198 PARA_ERROR_LOG("can not set SO_REUSEADDR: %s\n",
200 return -ERRNO_TO_PARA_ERROR(errno);
204 if (bind(sockfd, src->ai_addr, src->ai_addrlen) < 0) {
208 if (!dst) /* bind-only completed successfully */
212 if (dst && connect(sockfd, dst->ai_addr, dst->ai_addrlen) == 0)
213 break; /* connection completed successfully */
216 if (dst && (dst = dst->ai_next))
219 if (src && (src = src->ai_next)) /* restart inner loop */
225 freeaddrinfo(remote);
227 if (src == NULL && dst == NULL) {
228 PARA_ERROR_LOG("can not create %s socket %s#%s.\n",
229 layer4_name(l4type), host? host : (passive?
230 "[loopback]" : "[localhost]"), port);
231 return -ERRNO_TO_PARA_ERROR(errno);
237 * Create a passive / listening socket.
239 * \param l3type The network-layer type (\p AF_xxx).
240 * \param l4type The transport-layer type (\p IPPROTO_xxx).
241 * \param port The decimal port number to listen on.
243 * \return Positive integer (socket descriptor) on success, negative value
246 * \sa makesock(), ip(7), ipv6(7), bind(2), listen(2).
248 int para_listen(unsigned l3type, unsigned l4type, unsigned short port)
250 int ret, fd = makesock(l3type, l4type, 1, NULL, port);
253 ret = listen(fd, BACKLOG);
256 return -ERRNO_TO_PARA_ERROR(errno);
258 PARA_INFO_LOG("listening on %s port %u, fd %d\n",
259 layer4_name(l4type), port, fd);
265 * Print numeric host and port number (beware - uses static char).
267 * \param sa The IPv4/IPv6 socket address to use.
268 * \param len The length of \p sa.
270 * \sa getnameinfo(3).
272 static char *host_and_port(struct sockaddr *sa, socklen_t len)
274 static char output[NI_MAXHOST + NI_MAXSERV + 2];
275 char hbuf[NI_MAXHOST], sbuf[NI_MAXSERV];
278 ret = getnameinfo(sa, len, hbuf, sizeof(hbuf), sbuf, sizeof(sbuf),
279 NI_NUMERICHOST | NI_NUMERICSERV);
281 PARA_WARNING_LOG("hostname lookup error (%s).\n",
283 sprintf(output, "(unknown)");
285 sprintf(output, "%s#%s", hbuf, sbuf);
290 * Look up the local or remote side of a connected socket structure.
292 * \param fd The socket descriptor of the connected socket.
293 * \param getname Either \p getsockname() for local, or \p getpeername() for
296 * \return A static character string identifying hostname and port of the
299 * \sa getsockname(2), getpeername(2).
301 static char *__get_sock_name(int fd, int (*getname)(int, struct sockaddr*,
304 struct sockaddr_storage ss;
305 socklen_t sslen = sizeof(ss);
307 if (getname(fd, (struct sockaddr *)&ss, &sslen) < 0) {
308 static char *dont_know = "(don't know)";
309 PARA_ERROR_LOG("can not determine address from fd %d: %s\n",
310 fd, strerror(errno));
313 return host_and_port((struct sockaddr *)&ss, sslen);
316 char *local_name(int sockfd)
318 return __get_sock_name(sockfd, getsockname);
321 char *remote_name(int sockfd)
323 return __get_sock_name(sockfd, getpeername);
327 * Extract IPv4 or IPv6-mapped-IPv4 address from sockaddr_storage.
328 * \param ss Container of IPv4/6 address
329 * \return Extracted IPv4 address (different from 0) or 0 if unsuccessful.
333 struct in_addr extract_v4_addr(const struct sockaddr_storage *ss)
335 struct in_addr ia = {.s_addr = 0};
337 if (ss->ss_family == AF_INET)
338 ia.s_addr = ((struct sockaddr_in *)ss)->sin_addr.s_addr;
339 if (ss->ss_family == AF_INET6) {
340 const struct in6_addr v6_addr = ((struct sockaddr_in6 *)ss)->sin6_addr;
342 if (IN6_IS_ADDR_V4MAPPED(&v6_addr))
343 memcpy(&ia.s_addr, &(v6_addr.s6_addr[12]), 4);
349 * Send out a buffer, resend on short writes.
351 * \param fd The file descriptor.
352 * \param buf The buffer to be sent.
353 * \param len The length of \a buf.
355 * \return Standard. In any case, the number of bytes actually sent is stored
358 static int sendall(int fd, const char *buf, size_t *len)
364 while (*len < total) {
365 int ret = write(fd, buf + *len, total - *len);
367 return -ERRNO_TO_PARA_ERROR(errno);
374 * Encrypt and send a binary buffer.
376 * \param fd The file descriptor.
377 * \param buf The buffer to be encrypted and sent.
378 * \param len The length of \a buf.
380 * Check if encryption is available. If yes, encrypt the given buffer. Send
381 * out the buffer, encrypted or not, and try to resend the remaing part in case
386 int send_bin_buffer(int fd, const char *buf, size_t len)
389 crypt_function *cf = NULL;
392 PARA_CRIT_LOG("len == 0\n");
393 if (fd + 1 <= cda_size)
394 cf = crypt_data_array[fd].send;
396 void *private = crypt_data_array[fd].private_data;
397 /* RC4 may write more than len to the output buffer */
398 unsigned char *outbuf = para_malloc(ROUND_UP(len, 8));
399 (*cf)(len, (unsigned char *)buf, outbuf, private);
400 ret = sendall(fd, (char *)outbuf, &len);
403 ret = sendall(fd, buf, &len);
408 * Encrypt and send null terminated buffer.
410 * \param fd The file descriptor.
411 * \param buf The null-terminated buffer to be send.
413 * This is equivalent to send_bin_buffer(fd, buf, strlen(buf)).
417 int send_buffer(int fd, const char *buf)
419 return send_bin_buffer(fd, buf, strlen(buf));
424 * Send and encrypt a buffer given by a format string.
426 * \param fd The file descriptor.
427 * \param fmt A format string.
431 __printf_2_3 int send_va_buffer(int fd, const char *fmt, ...)
436 PARA_VSPRINTF(fmt, msg);
437 ret = send_buffer(fd, msg);
443 * Receive and decrypt.
445 * \param fd The file descriptor.
446 * \param buf The buffer to write the decrypted data to.
447 * \param size The size of \a buf.
449 * Receive at most \a size bytes from file descriptor \a fd. If encryption is
450 * available, decrypt the received buffer.
452 * \return The number of bytes received on success, negative on errors.
456 __must_check int recv_bin_buffer(int fd, char *buf, size_t size)
459 crypt_function *cf = NULL;
461 if (fd + 1 <= cda_size)
462 cf = crypt_data_array[fd].recv;
464 unsigned char *tmp = para_malloc(size);
465 void *private = crypt_data_array[fd].private_data;
466 n = recv(fd, tmp, size, 0);
469 unsigned char *b = (unsigned char *)buf;
470 (*cf)(numbytes, tmp, b, private);
474 n = recv(fd, buf, size, 0);
476 return -ERRNO_TO_PARA_ERROR(errno);
481 * Receive, decrypt and write terminating NULL byte.
483 * \param fd The file descriptor.
484 * \param buf The buffer to write the decrypted data to.
485 * \param size The size of \a buf.
487 * Read and decrypt at most \a size - 1 bytes from file descriptor \a fd and
488 * write a NULL byte at the end of the received data.
490 * \return The return value of the underlying call to \a recv_bin_buffer().
492 * \sa recv_bin_buffer()
494 int recv_buffer(int fd, char *buf, size_t size)
499 n = recv_bin_buffer(fd, buf, size - 1);
508 * Wrapper around the accept system call.
510 * \param fd The listening socket.
511 * \param addr Structure which is filled in with the address of the peer socket.
512 * \param size Should contain the size of the structure pointed to by \a addr.
514 * Accept incoming connections on \a addr. Retry if interrupted.
516 * \return The new file descriptor on success, negative on errors.
520 int para_accept(int fd, void *addr, socklen_t size)
525 new_fd = accept(fd, (struct sockaddr *) addr, &size);
526 while (new_fd < 0 && errno == EINTR);
527 return new_fd < 0? -ERRNO_TO_PARA_ERROR(errno) : new_fd;
531 * Prepare a structure for \p AF_UNIX socket addresses.
533 * \param u Pointer to the struct to be prepared.
534 * \param name The socket pathname.
536 * This just copies \a name to the sun_path component of \a u.
538 * \return Positive on success, \p -E_NAME_TOO_LONG if \a name is longer
539 * than \p UNIX_PATH_MAX.
541 static int init_unix_addr(struct sockaddr_un *u, const char *name)
543 if (strlen(name) >= UNIX_PATH_MAX)
544 return -E_NAME_TOO_LONG;
545 memset(u->sun_path, 0, UNIX_PATH_MAX);
546 u->sun_family = PF_UNIX;
547 strcpy(u->sun_path, name);
552 * Prepare, create, and bind a socket for local communication.
554 * \param name The socket pathname.
555 * \param unix_addr Pointer to the \p AF_UNIX socket structure.
556 * \param mode The desired mode of the socket.
558 * This function creates a local socket for sequenced, reliable,
559 * two-way, connection-based byte streams.
561 * \return The file descriptor, on success, negative on errors.
567 int create_local_socket(const char *name, struct sockaddr_un *unix_addr,
572 ret = init_unix_addr(unix_addr, name);
575 ret = socket(PF_UNIX, SOCK_STREAM, 0);
577 return -ERRNO_TO_PARA_ERROR(errno);
579 ret = bind(fd, (struct sockaddr *) unix_addr, UNIX_PATH_MAX);
581 ret = -ERRNO_TO_PARA_ERROR(errno);
585 if (chmod(name, mode) < 0)
594 * Prepare, create, and connect to a Unix domain socket for local communication.
596 * \param name The socket pathname.
598 * This function creates a local socket for sequenced, reliable, two-way,
599 * connection-based byte streams.
601 * \return The file descriptor, on success, negative on errors.
603 * \sa create_local_socket(), unix(7), connect(2).
605 int create_remote_socket(const char *name)
607 struct sockaddr_un unix_addr;
610 ret = init_unix_addr(&unix_addr, name);
613 fd = socket(PF_UNIX, SOCK_STREAM, 0);
615 return -ERRNO_TO_PARA_ERROR(errno);
616 if (connect(fd, (struct sockaddr *)&unix_addr, sizeof(unix_addr)) == -1) {
617 ret = -ERRNO_TO_PARA_ERROR(errno);
627 ssize_t send_cred_buffer(int sock, char *buf)
629 return send_buffer(sock, buf);
631 int recv_cred_buffer(int fd, char *buf, size_t size)
633 return recv_buffer(fd, buf, size) > 0? 1 : -E_RECVMSG;
635 #else /* HAVE_UCRED */
637 * Send \p NULL-terminated buffer and Unix credentials of the current process.
639 * \param sock The socket file descriptor.
640 * \param buf The buffer to be sent.
642 * \return On success, this call returns the number of characters sent. On
643 * error, \p -E_SENDMSG is returned.
645 * \sa sendmsg(2), okir's Black Hats Manual.
647 ssize_t send_cred_buffer(int sock, char *buf)
649 char control[sizeof(struct cmsghdr) + 10];
651 struct cmsghdr *cmsg;
652 static struct iovec iov;
658 iov.iov_len = strlen(buf);
662 /* compose the message */
663 memset(&msg, 0, sizeof(msg));
666 msg.msg_control = control;
667 msg.msg_controllen = sizeof(control);
668 /* attach the ucred struct */
669 cmsg = CMSG_FIRSTHDR(&msg);
670 cmsg->cmsg_level = SOL_SOCKET;
671 cmsg->cmsg_type = SCM_CREDENTIALS;
672 cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred));
673 *(struct ucred *)CMSG_DATA(cmsg) = c;
674 msg.msg_controllen = cmsg->cmsg_len;
675 ret = sendmsg(sock, &msg, 0);
681 static void dispose_fds(int *fds, unsigned num)
685 for (i = 0; i < num; i++)
690 * Receive a buffer and the Unix credentials of the sending process.
692 * \param fd the socket file descriptor.
693 * \param buf the buffer to store the message.
694 * \param size the size of \a buffer.
696 * \return negative on errors, the user id on success.
698 * \sa recvmsg(2), okir's Black Hats Manual.
700 int recv_cred_buffer(int fd, char *buf, size_t size)
704 struct cmsghdr *cmsg;
710 setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &yes, sizeof(int));
711 memset(&msg, 0, sizeof(msg));
712 memset(buf, 0, size);
717 msg.msg_control = control;
718 msg.msg_controllen = sizeof(control);
719 if (recvmsg(fd, &msg, 0) < 0)
721 result = -E_SCM_CREDENTIALS;
722 cmsg = CMSG_FIRSTHDR(&msg);
724 if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type
725 == SCM_CREDENTIALS) {
726 memcpy(&cred, CMSG_DATA(cmsg), sizeof(struct ucred));
729 if (cmsg->cmsg_level == SOL_SOCKET
730 && cmsg->cmsg_type == SCM_RIGHTS) {
731 dispose_fds((int *) CMSG_DATA(cmsg),
732 (cmsg->cmsg_len - CMSG_LEN(0))
735 cmsg = CMSG_NXTHDR(&msg, cmsg);
739 #endif /* HAVE_UCRED */
742 * Receive a buffer and check for a pattern.
744 * \param fd The file descriptor to receive from.
745 * \param pattern The expected pattern.
746 * \param bufsize The size of the internal buffer.
748 * \return Positive if \a pattern was received, negative otherwise.
750 * This function creates a buffer of size \a bufsize and tries
751 * to receive at most \a bufsize bytes from file descriptor \a fd.
752 * If at least \p strlen(\a pattern) bytes were received, the beginning of
753 * the received buffer is compared with \a pattern, ignoring case.
755 * \sa recv_buffer(), \sa strncasecmp(3).
757 int recv_pattern(int fd, const char *pattern, size_t bufsize)
759 size_t len = strlen(pattern);
760 char *buf = para_malloc(bufsize + 1);
761 int ret = -E_RECV_PATTERN, n = recv_buffer(fd, buf, bufsize);
765 if (strncasecmp(buf, pattern, len))
770 PARA_NOTICE_LOG("n = %d, did not receive pattern '%s'\n", n,
773 PARA_NOTICE_LOG("recvd: %s\n", buf);