2 * Copyright (C) 2005-2007 Andre Noll <maan@systemlinux.org>
4 * Licensed under the GPL v2. For licencing details see COPYING.
7 /** \file net.c networking-related helper functions */
15 /** holds information about one encrypted connection */
17 /** function used to decrypt received data */
19 /** function used to encrypt data to be sent */
21 /** context-dependent data, passed to \a recv() and \a send() */
24 /** array holding per fd crypt data per */
25 static struct crypt_data *crypt_data_array;
26 /** current size of the crypt data array */
27 static unsigned cda_size = 0;
31 * activate encryption for one file descriptor
33 * \param fd the file descriptor
34 * \param recv_f the function used for decrypting received data
35 * \param send_f the function used for encrypting before sending
36 * \param private_data user data supplied by the caller
38 void enable_crypt(int fd, crypt_function *recv_f, crypt_function *send_f,
41 if (fd + 1 > cda_size) {
42 crypt_data_array = para_realloc(crypt_data_array,
43 (fd + 1) * sizeof(struct crypt_data));
44 memset(crypt_data_array + cda_size, 0,
45 (fd + 1 - cda_size) * sizeof(struct crypt_data));
48 crypt_data_array[fd].recv = recv_f;
49 crypt_data_array[fd].send = send_f;
50 crypt_data_array[fd].private_data = private_data;
51 PARA_INFO_LOG("rc4 encryption activated for fd %d\n", fd);
55 * deactivate encryption for a given fd
57 * \param fd the file descriptor
59 * This must be called if and only if \p fd was activated via enable_crypt().
61 void disable_crypt(int fd)
63 if (cda_size < fd + 1)
65 crypt_data_array[fd].recv = NULL;
66 crypt_data_array[fd].send = NULL;
67 crypt_data_array[fd].private_data = NULL;
72 * initialize a struct sockaddr_in
74 * \param addr A pointer to the struct to be initialized
75 * \param port The port number to use
76 * \param he The address to use
78 * If \a he is null (server mode), \a addr->sin_addr is initialized with \p
79 * INADDR_ANY. Otherwise, the address given by \a he is copied to addr.
81 void init_sockaddr(struct sockaddr_in *addr, int port, const struct hostent *he)
84 addr->sin_family = AF_INET;
85 /* short, network byte order */
86 addr->sin_port = htons(port);
88 addr->sin_addr = *((struct in_addr *)he->h_addr);
90 addr->sin_addr.s_addr = INADDR_ANY;
91 /* zero the rest of the struct */
92 memset(&addr->sin_zero, '\0', 8);
96 * send out a buffer, resend on short writes
98 * \param fd the file descriptor
99 * \param buf The buffer to be sent
100 * \param len The length of \a buf
102 * Due to circumstances beyond your control, the kernel might not send all the
103 * data out in one chunk, and now, my friend, it's up to us to get the data out
104 * there (Beej's Guide to Network Programming).
106 * \return This function returns 1 on success and \a -E_SEND on errors. The
107 * number of bytes actually sent is stored upon successful return in \a len.
109 static int sendall(int fd, const char *buf, size_t *len)
111 size_t total = 0, bytesleft = *len; /* how many we have left to send */
114 while (total < *len) {
115 n = send(fd, buf + total, bytesleft, 0);
121 PARA_DEBUG_LOG("short write (%zd byte(s) left)",
124 *len = total; /* return number actually sent here */
125 return n == -1? -E_SEND : 1; /* return 1 on success */
129 * encrypt and send buffer
131 * \param fd: the file descriptor
132 * \param buf the buffer to be encrypted and sent
133 * \param len the length of \a buf
135 * Check if encrytpion is available. If yes, encrypt the given buffer. Send out
136 * the buffer, encrypted or not, and try to resend the remaing part in case of
139 * \return Positive on success, \p -E_SEND on errors.
141 int send_bin_buffer(int fd, const char *buf, size_t len)
144 crypt_function *cf = NULL;
147 PARA_CRIT_LOG("%s", "len == 0\n");
148 if (fd + 1 <= cda_size)
149 cf = crypt_data_array[fd].send;
151 void *private = crypt_data_array[fd].private_data;
152 unsigned char *outbuf = para_malloc(len);
153 (*cf)(len, (unsigned char *)buf, outbuf, private);
154 ret = sendall(fd, (char *)outbuf, &len);
157 ret = sendall(fd, buf, &len);
162 * encrypt and send null terminated buffer.
164 * \param fd the file descriptor
165 * \param buf the null-terminated buffer to be send
167 * This is equivalent to send_bin_buffer(fd, buf, strlen(buf)).
169 * \return Positive on success, \p -E_SEND on errors.
171 int send_buffer(int fd, const char *buf)
173 return send_bin_buffer(fd, buf, strlen(buf));
178 * send and encrypt a buffer given by a format string
180 * \param fd the file descriptor
181 * \param fmt a format string
183 * \return Positive on success, \p -E_SEND on errors.
185 __printf_2_3 int send_va_buffer(int fd, const char *fmt, ...)
190 PARA_VSPRINTF(fmt, msg);
191 ret = send_buffer(fd, msg);
197 * receive and decrypt.
199 * \param fd the file descriptor
200 * \param buf the buffer to write the decrypted data to
201 * \param size the size of \a buf
203 * Receive at most \a size bytes from filedescriptor fd. If encryption is
204 * available, decrypt the received buffer.
206 * \return The number of bytes received on success. On receive errors, -E_RECV
207 * is returned. On crypt errors, the corresponding crypt error number is
212 __must_check int recv_bin_buffer(int fd, char *buf, size_t size)
215 crypt_function *cf = NULL;
217 if (fd + 1 <= cda_size)
218 cf = crypt_data_array[fd].recv;
220 unsigned char *tmp = para_malloc(size);
221 void *private = crypt_data_array[fd].private_data;
222 n = recv(fd, tmp, size, 0);
225 unsigned char *b = (unsigned char *)buf;
226 (*cf)(numbytes, tmp, b, private);
230 n = recv(fd, buf, size, 0);
237 * receive, decrypt and write terminating NULL byte
239 * \param fd the file descriptor
240 * \param buf the buffer to write the decrypted data to
241 * \param size the size of \a buf
243 * Read and decrypt at most \a size - 1 bytes from file descriptor \a fd and
244 * write a NULL byte at the end of the received data.
246 * \return: The return value of the underlying call to \a recv_bin_buffer().
248 * \sa recv_bin_buffer()
250 int recv_buffer(int fd, char *buf, size_t size)
256 n = recv_bin_buffer(fd, buf, size - 1);
265 * wrapper around gethostbyname
267 * \param host hostname or IPv4 address
268 * \param ret the hostent structure is returned here
270 * \return positive on success, negative on errors. On success, \a ret
271 * contains the return value of the underlying gethostbyname() call.
273 * \sa gethostbyname(2)
275 int get_host_info(char *host, struct hostent **ret)
277 PARA_INFO_LOG("getting host info of %s\n", host);
278 /* FIXME: gethostbyname() is obsolete */
279 *ret = gethostbyname(host);
280 return *ret? 1 : -E_HOST_INFO;
284 * a wrapper around socket(2)
286 * Create an IPv4 socket for sequenced, reliable, two-way, connection-based
289 * \return The socket fd on success, -E_SOCKET on errors.
297 if ((socket_fd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
303 * a wrapper around connect(2)
305 * \param fd the file descriptor
306 * \param their_addr the address to connect
308 * \return \p -E_CONNECT on errors, 1 on success
312 int para_connect(int fd, struct sockaddr_in *their_addr)
316 if ((ret = connect(fd, (struct sockaddr *)their_addr,
317 sizeof(struct sockaddr))) == -1)
323 * paraslash's wrapper around the accept system call
325 * \param fd the listening socket
326 * \param addr structure which is filled in with the address of the peer socket
327 * \param size should contain the size of the structure pointed to by \a addr
329 * Accept incoming connections on \a addr. Retry if interrupted.
331 * \return The new file descriptor on success, \a -E_ACCEPT on errors.
335 int para_accept(int fd, void *addr, socklen_t size)
340 new_fd = accept(fd, (struct sockaddr *) addr, &size);
341 while (new_fd < 0 && errno == EINTR);
342 return new_fd < 0? -E_ACCEPT : new_fd;
345 static int setserversockopts(int socket_fd)
349 if (setsockopt(socket_fd, SOL_SOCKET, SO_REUSEADDR, &yes,
351 return -E_SETSOCKOPT;
356 * prepare a structure for \p AF_UNIX socket addresses
358 * \param u pointer to the struct to be prepared
359 * \param name the socket pathname
361 * This just copies \a name to the sun_path component of \a u.
363 * \return Positive on success, \p -E_NAME_TOO_LONG if \a name is longer
364 * than \p UNIX_PATH_MAX.
366 int init_unix_addr(struct sockaddr_un *u, const char *name)
368 if (strlen(name) >= UNIX_PATH_MAX)
369 return -E_NAME_TOO_LONG;
370 memset(u->sun_path, 0, UNIX_PATH_MAX);
371 u->sun_family = PF_UNIX;
372 strcpy(u->sun_path, name);
377 * prepare, create, and bind and socket for local communication
379 * \param name the socket pathname
380 * \param unix_addr pointer to the \p AF_UNIX socket structure
381 * \param mode the desired mode of the socket
383 * This functions creates a local socket for sequenced, reliable,
384 * two-way, connection-based byte streams.
386 * \return The file descriptor, on success, negative on errors.
392 int create_local_socket(const char *name, struct sockaddr_un *unix_addr,
397 fd = socket(PF_UNIX, SOCK_STREAM, 0);
401 ret = init_unix_addr(unix_addr, name);
404 if (bind(fd, (struct sockaddr *) unix_addr, UNIX_PATH_MAX) < 0)
406 if (chmod(name, mode) < 0)
412 ssize_t send_cred_buffer(int sock, char *buf)
414 return send_buffer(sock, buf);
416 int recv_cred_buffer(int fd, char *buf, size_t size)
418 return recv_buffer(fd, buf, size) > 0? 1 : -E_RECVMSG;
420 #else /* HAVE_UCRED */
422 * send NULL terminated buffer and Unix credentials of the current process
424 * \param sock the socket file descriptor
425 * \param buf the buffer to be sent
427 * \return On success, this call returns the number of characters sent. On
428 * error, \p -E_SENDMSG ist returned.
430 * \sa okir's Black Hats Manual
433 ssize_t send_cred_buffer(int sock, char *buf)
435 char control[sizeof(struct cmsghdr) + 10];
437 struct cmsghdr *cmsg;
438 static struct iovec iov;
444 iov.iov_len = strlen(buf);
448 /* compose the message */
449 memset(&msg, 0, sizeof(msg));
452 msg.msg_control = control;
453 msg.msg_controllen = sizeof(control);
454 /* attach the ucred struct */
455 cmsg = CMSG_FIRSTHDR(&msg);
456 cmsg->cmsg_level = SOL_SOCKET;
457 cmsg->cmsg_type = SCM_CREDENTIALS;
458 cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred));
459 *(struct ucred *)CMSG_DATA(cmsg) = c;
460 msg.msg_controllen = cmsg->cmsg_len;
461 ret = sendmsg(sock, &msg, 0);
467 static void dispose_fds(int *fds, unsigned num)
471 for (i = 0; i < num; i++)
476 * receive a buffer and the Unix credentials of the sending process
478 * \param fd the socket file descriptor
479 * \param buf the buffer to store the message
480 * \param size the size of \a buffer
482 * \return negative on errors, the user id on success.
484 * \sa okir's Black Hats Manual
487 int recv_cred_buffer(int fd, char *buf, size_t size)
491 struct cmsghdr *cmsg;
497 setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &yes, sizeof(int));
498 memset(&msg, 0, sizeof(msg));
499 memset(buf, 0, size);
504 msg.msg_control = control;
505 msg.msg_controllen = sizeof(control);
506 if (recvmsg(fd, &msg, 0) < 0)
508 result = -E_SCM_CREDENTIALS;
509 cmsg = CMSG_FIRSTHDR(&msg);
511 if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type
512 == SCM_CREDENTIALS) {
513 memcpy(&cred, CMSG_DATA(cmsg), sizeof(struct ucred));
516 if (cmsg->cmsg_level == SOL_SOCKET
517 && cmsg->cmsg_type == SCM_RIGHTS) {
518 dispose_fds((int *) CMSG_DATA(cmsg),
519 (cmsg->cmsg_len - CMSG_LEN(0))
522 cmsg = CMSG_NXTHDR(&msg, cmsg);
526 #endif /* HAVE_UCRED */
528 /** how many pending connections queue will hold */
532 * create a socket, bind it and listen
534 * \param port the tcp port to listen on
536 * \return The file descriptor of the created socket, negative
544 int init_tcp_socket(int port)
546 struct sockaddr_in my_addr;
547 int fd, ret = get_socket();
552 ret = setserversockopts(fd);
555 init_sockaddr(&my_addr, port, NULL);
557 if (bind(fd, (struct sockaddr *)&my_addr,
558 sizeof(struct sockaddr)) == -1) {
559 PARA_CRIT_LOG("bind error: %s\n", strerror(errno));
563 if (listen(fd, BACKLOG) == -1)
565 PARA_INFO_LOG("listening on port %d, fd %d\n", port, fd);
573 * receive a buffer and check for a pattern
575 * \param fd the file descriptor to receive from
576 * \param pattern the expected pattern
577 * \param bufsize the size of the internal buffer
579 * \return Positive if \a pattern was received, negative otherwise.
581 * This function creates a buffer of size \a bufsize and tries
582 * to receive at most \a bufsize bytes from file descriptor \a fd.
583 * If at least \p strlen(\a pattern) bytes were received, the beginning of
584 * the received buffer is compared with \a pattern, ignoring case.
589 int recv_pattern(int fd, const char *pattern, size_t bufsize)
591 size_t len = strlen(pattern);
592 char *buf = para_malloc(bufsize + 1);
593 int ret = -E_RECV_PATTERN, n = recv_buffer(fd, buf, bufsize);
597 if (strncasecmp(buf, pattern, len))
602 PARA_NOTICE_LOG("n = %d, did not receive pattern '%s'\n", n, pattern);
604 PARA_NOTICE_LOG("recvd: %s\n", buf);