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 /** Information about one encrypted connection. */
17 /** Function used to decrypt received data. */
19 /** Function used to encrypt data to be sent. */
22 * Context-dependent data (crypt keys), passed verbatim to the above
27 /** Array holding per fd crypt data. */
28 static struct crypt_data *crypt_data_array;
29 /** Current size of the crypt data array. */
30 static unsigned cda_size = 0;
33 * Activate encryption for one file descriptor.
35 * \param fd The file descriptor.
36 * \param recv_f The function used for decrypting received data.
37 * \param send_f The function used for encrypting before sending.
38 * \param private_data User data supplied by the caller.
40 void enable_crypt(int fd, crypt_function *recv_f, crypt_function *send_f,
43 if (fd + 1 > cda_size) {
44 crypt_data_array = para_realloc(crypt_data_array,
45 (fd + 1) * sizeof(struct crypt_data));
46 memset(crypt_data_array + cda_size, 0,
47 (fd + 1 - cda_size) * sizeof(struct crypt_data));
50 crypt_data_array[fd].recv = recv_f;
51 crypt_data_array[fd].send = send_f;
52 crypt_data_array[fd].private_data = private_data;
53 PARA_INFO_LOG("rc4 encryption activated for fd %d\n", fd);
57 * Deactivate encryption for a given fd.
59 * \param fd The file descriptor.
61 * This must be called if and only if \p fd was activated via enable_crypt().
63 void disable_crypt(int fd)
65 if (cda_size < fd + 1)
67 crypt_data_array[fd].recv = NULL;
68 crypt_data_array[fd].send = NULL;
69 crypt_data_array[fd].private_data = NULL;
74 * Initialize a struct sockaddr_in.
76 * \param addr A pointer to the struct to be initialized.
77 * \param port The port number to use.
78 * \param he The address to use.
80 * If \a he is null (server mode), \a addr->sin_addr is initialized with \p
81 * INADDR_ANY. Otherwise, the address given by \a he is copied to addr.
83 void init_sockaddr(struct sockaddr_in *addr, int port, const struct hostent *he)
86 addr->sin_family = AF_INET;
87 /* short, network byte order */
88 addr->sin_port = htons(port);
90 addr->sin_addr = *((struct in_addr *)he->h_addr);
92 addr->sin_addr.s_addr = INADDR_ANY;
93 /* zero the rest of the struct */
94 memset(&addr->sin_zero, '\0', 8);
98 * Send out a buffer, resend on short writes.
100 * \param fd The file descriptor.
101 * \param buf The buffer to be sent.
102 * \param len The length of \a buf.
104 * \return Standard. In any case, the number of bytes actually sent is stored
107 static int sendall(int fd, const char *buf, size_t *len)
113 while (*len < total) {
114 int ret = send(fd, buf + *len, total - *len, 0);
116 return -ERRNO_TO_PARA_ERROR(errno);
123 * Encrypt and send a binary buffer.
125 * \param fd The file descriptor.
126 * \param buf The buffer to be encrypted and sent.
127 * \param len The length of \a buf.
129 * Check if encryption is available. If yes, encrypt the given buffer. Send
130 * out the buffer, encrypted or not, and try to resend the remaing part in case
135 int send_bin_buffer(int fd, const char *buf, size_t len)
138 crypt_function *cf = NULL;
141 PARA_CRIT_LOG("%s", "len == 0\n");
142 if (fd + 1 <= cda_size)
143 cf = crypt_data_array[fd].send;
145 void *private = crypt_data_array[fd].private_data;
146 /* RC4 may write more than len to the output buffer */
147 unsigned char *outbuf = para_malloc(ROUND_UP(len, 8));
148 (*cf)(len, (unsigned char *)buf, outbuf, private);
149 ret = sendall(fd, (char *)outbuf, &len);
152 ret = sendall(fd, buf, &len);
157 * Encrypt and send null terminated buffer.
159 * \param fd The file descriptor.
160 * \param buf The null-terminated buffer to be send.
162 * This is equivalent to send_bin_buffer(fd, buf, strlen(buf)).
166 int send_buffer(int fd, const char *buf)
168 return send_bin_buffer(fd, buf, strlen(buf));
173 * Send and encrypt a buffer given by a format string.
175 * \param fd The file descriptor.
176 * \param fmt A format string.
180 __printf_2_3 int send_va_buffer(int fd, const char *fmt, ...)
185 PARA_VSPRINTF(fmt, msg);
186 ret = send_buffer(fd, msg);
192 * Receive and decrypt.
194 * \param fd The file descriptor.
195 * \param buf The buffer to write the decrypted data to.
196 * \param size The size of \a buf.
198 * Receive at most \a size bytes from file descriptor \a fd. If encryption is
199 * available, decrypt the received buffer.
201 * \return The number of bytes received on success, negative on errors.
205 __must_check int recv_bin_buffer(int fd, char *buf, size_t size)
208 crypt_function *cf = NULL;
210 if (fd + 1 <= cda_size)
211 cf = crypt_data_array[fd].recv;
213 unsigned char *tmp = para_malloc(size);
214 void *private = crypt_data_array[fd].private_data;
215 n = recv(fd, tmp, size, 0);
218 unsigned char *b = (unsigned char *)buf;
219 (*cf)(numbytes, tmp, b, private);
223 n = recv(fd, buf, size, 0);
225 return -ERRNO_TO_PARA_ERROR(errno);
230 * Receive, decrypt and write terminating NULL byte.
232 * \param fd The file descriptor.
233 * \param buf The buffer to write the decrypted data to.
234 * \param size The size of \a buf.
236 * Read and decrypt at most \a size - 1 bytes from file descriptor \a fd and
237 * write a NULL byte at the end of the received data.
239 * \return The return value of the underlying call to \a recv_bin_buffer().
241 * \sa recv_bin_buffer()
243 int recv_buffer(int fd, char *buf, size_t size)
248 n = recv_bin_buffer(fd, buf, size - 1);
257 * wrapper around gethostbyname
259 * \param host hostname or IPv4 address
260 * \param ret the hostent structure is returned here
262 * \return positive on success, negative on errors. On success, \a ret
263 * contains the return value of the underlying gethostbyname() call.
265 * \sa gethostbyname(2)
267 int get_host_info(char *host, struct hostent **ret)
269 PARA_INFO_LOG("getting host info of %s\n", host);
270 /* FIXME: gethostbyname() is obsolete */
271 *ret = gethostbyname(host);
272 return *ret? 1 : -E_HOST_INFO;
276 * A wrapper around socket(2).
278 * \param domain The communication domain that selects the protocol family.
280 * \return The socket fd on success, -E_SOCKET on errors.
282 * Create an IPv4 socket for sequenced, reliable, two-way, connection-based
287 int get_stream_socket(int domain)
291 if ((socket_fd = socket(domain, SOCK_STREAM, 0)) == -1)
297 * Wrapper around the accept system call.
299 * \param fd The listening socket.
300 * \param addr Structure which is filled in with the address of the peer socket.
301 * \param size Should contain the size of the structure pointed to by \a addr.
303 * Accept incoming connections on \a addr. Retry if interrupted.
305 * \return The new file descriptor on success, negative on errors.
309 int para_accept(int fd, void *addr, socklen_t size)
314 new_fd = accept(fd, (struct sockaddr *) addr, &size);
315 while (new_fd < 0 && errno == EINTR);
316 return new_fd < 0? -ERRNO_TO_PARA_ERROR(errno) : new_fd;
319 static int setserversockopts(int socket_fd)
323 if (setsockopt(socket_fd, SOL_SOCKET, SO_REUSEADDR, &yes,
325 return -E_SETSOCKOPT;
330 * prepare a structure for \p AF_UNIX socket addresses
332 * \param u pointer to the struct to be prepared
333 * \param name the socket pathname
335 * This just copies \a name to the sun_path component of \a u.
337 * \return Positive on success, \p -E_NAME_TOO_LONG if \a name is longer
338 * than \p UNIX_PATH_MAX.
340 int init_unix_addr(struct sockaddr_un *u, const char *name)
342 if (strlen(name) >= UNIX_PATH_MAX)
343 return -E_NAME_TOO_LONG;
344 memset(u->sun_path, 0, UNIX_PATH_MAX);
345 u->sun_family = PF_UNIX;
346 strcpy(u->sun_path, name);
351 * Prepare, create, and bind a socket for local communication.
353 * \param name The socket pathname.
354 * \param unix_addr Pointer to the \p AF_UNIX socket structure.
355 * \param mode The desired mode of the socket.
357 * This functions creates a local socket for sequenced, reliable,
358 * two-way, connection-based byte streams.
360 * \return The file descriptor, on success, negative on errors.
366 int create_local_socket(const char *name, struct sockaddr_un *unix_addr,
371 ret = init_unix_addr(unix_addr, name);
374 fd = socket(PF_UNIX, SOCK_STREAM, 0);
378 if (bind(fd, (struct sockaddr *) unix_addr, UNIX_PATH_MAX) < 0)
381 if (chmod(name, mode) < 0)
390 ssize_t send_cred_buffer(int sock, char *buf)
392 return send_buffer(sock, buf);
394 int recv_cred_buffer(int fd, char *buf, size_t size)
396 return recv_buffer(fd, buf, size) > 0? 1 : -E_RECVMSG;
398 #else /* HAVE_UCRED */
400 * send NULL terminated buffer and Unix credentials of the current process
402 * \param sock the socket file descriptor
403 * \param buf the buffer to be sent
405 * \return On success, this call returns the number of characters sent. On
406 * error, \p -E_SENDMSG is returned.
408 * \sa okir's Black Hats Manual
411 ssize_t send_cred_buffer(int sock, char *buf)
413 char control[sizeof(struct cmsghdr) + 10];
415 struct cmsghdr *cmsg;
416 static struct iovec iov;
422 iov.iov_len = strlen(buf);
426 /* compose the message */
427 memset(&msg, 0, sizeof(msg));
430 msg.msg_control = control;
431 msg.msg_controllen = sizeof(control);
432 /* attach the ucred struct */
433 cmsg = CMSG_FIRSTHDR(&msg);
434 cmsg->cmsg_level = SOL_SOCKET;
435 cmsg->cmsg_type = SCM_CREDENTIALS;
436 cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred));
437 *(struct ucred *)CMSG_DATA(cmsg) = c;
438 msg.msg_controllen = cmsg->cmsg_len;
439 ret = sendmsg(sock, &msg, 0);
445 static void dispose_fds(int *fds, unsigned num)
449 for (i = 0; i < num; i++)
454 * receive a buffer and the Unix credentials of the sending process
456 * \param fd the socket file descriptor
457 * \param buf the buffer to store the message
458 * \param size the size of \a buffer
460 * \return negative on errors, the user id on success.
462 * \sa okir's Black Hats Manual
465 int recv_cred_buffer(int fd, char *buf, size_t size)
469 struct cmsghdr *cmsg;
475 setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &yes, sizeof(int));
476 memset(&msg, 0, sizeof(msg));
477 memset(buf, 0, size);
482 msg.msg_control = control;
483 msg.msg_controllen = sizeof(control);
484 if (recvmsg(fd, &msg, 0) < 0)
486 result = -E_SCM_CREDENTIALS;
487 cmsg = CMSG_FIRSTHDR(&msg);
489 if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type
490 == SCM_CREDENTIALS) {
491 memcpy(&cred, CMSG_DATA(cmsg), sizeof(struct ucred));
494 if (cmsg->cmsg_level == SOL_SOCKET
495 && cmsg->cmsg_type == SCM_RIGHTS) {
496 dispose_fds((int *) CMSG_DATA(cmsg),
497 (cmsg->cmsg_len - CMSG_LEN(0))
500 cmsg = CMSG_NXTHDR(&msg, cmsg);
504 #endif /* HAVE_UCRED */
506 /** how many pending connections queue will hold */
510 * create a socket, bind it and listen
512 * \param port the tcp port to listen on
514 * \return The file descriptor of the created socket, negative
517 * \sa get_stream_socket()
522 int init_tcp_socket(int port)
524 struct sockaddr_in my_addr;
525 int fd, ret = get_stream_socket(AF_INET);
530 ret = setserversockopts(fd);
533 init_sockaddr(&my_addr, port, NULL);
535 if (bind(fd, (struct sockaddr *)&my_addr,
536 sizeof(struct sockaddr)) == -1) {
537 PARA_CRIT_LOG("bind error: %s\n", strerror(errno));
541 if (listen(fd, BACKLOG) == -1)
543 PARA_INFO_LOG("listening on port %d, fd %d\n", port, fd);
551 * receive a buffer and check for a pattern
553 * \param fd the file descriptor to receive from
554 * \param pattern the expected pattern
555 * \param bufsize the size of the internal buffer
557 * \return Positive if \a pattern was received, negative otherwise.
559 * This function creates a buffer of size \a bufsize and tries
560 * to receive at most \a bufsize bytes from file descriptor \a fd.
561 * If at least \p strlen(\a pattern) bytes were received, the beginning of
562 * the received buffer is compared with \a pattern, ignoring case.
567 int recv_pattern(int fd, const char *pattern, size_t bufsize)
569 size_t len = strlen(pattern);
570 char *buf = para_malloc(bufsize + 1);
571 int ret = -E_RECV_PATTERN, n = recv_buffer(fd, buf, bufsize);
575 if (strncasecmp(buf, pattern, len))
580 PARA_NOTICE_LOG("n = %d, did not receive pattern '%s'\n", n, pattern);
582 PARA_NOTICE_LOG("recvd: %s\n", buf);