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 * Due to circumstances beyond your control, the kernel might not send all the
105 * data out in one chunk, and now, my friend, it's up to us to get the data out
106 * there (Beej's Guide to Network Programming).
108 * \return This function returns 1 on success and \a -E_SEND on errors. The
109 * number of bytes actually sent is stored upon successful return in \a len.
111 static int sendall(int fd, const char *buf, size_t *len)
113 size_t total = 0, bytesleft = *len; /* how many we have left to send */
116 while (total < *len) {
117 n = send(fd, buf + total, bytesleft, 0);
123 PARA_DEBUG_LOG("short write (%zd byte(s) left)\n",
126 *len = total; /* return number actually sent here */
127 return n == -1? -E_SEND : 1; /* return 1 on success */
131 * Encrypt and send a binary buffer.
133 * \param fd The file descriptor.
134 * \param buf The buffer to be encrypted and sent.
135 * \param len The length of \a buf.
137 * Check if encryption is available. If yes, encrypt the given buffer. Send
138 * out the buffer, encrypted or not, and try to resend the remaing part in case
141 * \return Positive on success, \p -E_SEND on errors.
143 int send_bin_buffer(int fd, const char *buf, size_t len)
146 crypt_function *cf = NULL;
149 PARA_CRIT_LOG("%s", "len == 0\n");
150 if (fd + 1 <= cda_size)
151 cf = crypt_data_array[fd].send;
153 void *private = crypt_data_array[fd].private_data;
154 /* RC4 may write more than len to the output buffer */
155 unsigned char *outbuf = para_malloc(ROUND_UP(len, 8));
156 (*cf)(len, (unsigned char *)buf, outbuf, private);
157 ret = sendall(fd, (char *)outbuf, &len);
160 ret = sendall(fd, buf, &len);
165 * encrypt and send null terminated buffer.
167 * \param fd the file descriptor
168 * \param buf the null-terminated buffer to be send
170 * This is equivalent to send_bin_buffer(fd, buf, strlen(buf)).
172 * \return Positive on success, \p -E_SEND on errors.
174 int send_buffer(int fd, const char *buf)
176 return send_bin_buffer(fd, buf, strlen(buf));
181 * send and encrypt a buffer given by a format string
183 * \param fd the file descriptor
184 * \param fmt a format string
186 * \return Positive on success, \p -E_SEND on errors.
188 __printf_2_3 int send_va_buffer(int fd, const char *fmt, ...)
193 PARA_VSPRINTF(fmt, msg);
194 ret = send_buffer(fd, msg);
200 * receive and decrypt.
202 * \param fd the file descriptor
203 * \param buf the buffer to write the decrypted data to
204 * \param size the size of \a buf
206 * Receive at most \a size bytes from filedescriptor fd. If encryption is
207 * available, decrypt the received buffer.
209 * \return The number of bytes received on success. On receive errors, -E_RECV
210 * is returned. On crypt errors, the corresponding crypt error number is
215 __must_check int recv_bin_buffer(int fd, char *buf, size_t size)
218 crypt_function *cf = NULL;
220 if (fd + 1 <= cda_size)
221 cf = crypt_data_array[fd].recv;
223 unsigned char *tmp = para_malloc(size);
224 void *private = crypt_data_array[fd].private_data;
225 n = recv(fd, tmp, size, 0);
228 unsigned char *b = (unsigned char *)buf;
229 (*cf)(numbytes, tmp, b, private);
233 n = recv(fd, buf, size, 0);
240 * receive, decrypt and write terminating NULL byte
242 * \param fd the file descriptor
243 * \param buf the buffer to write the decrypted data to
244 * \param size the size of \a buf
246 * Read and decrypt at most \a size - 1 bytes from file descriptor \a fd and
247 * write a NULL byte at the end of the received data.
249 * \return: The return value of the underlying call to \a recv_bin_buffer().
251 * \sa recv_bin_buffer()
253 int recv_buffer(int fd, char *buf, size_t size)
259 n = recv_bin_buffer(fd, buf, size - 1);
268 * wrapper around gethostbyname
270 * \param host hostname or IPv4 address
271 * \param ret the hostent structure is returned here
273 * \return positive on success, negative on errors. On success, \a ret
274 * contains the return value of the underlying gethostbyname() call.
276 * \sa gethostbyname(2)
278 int get_host_info(char *host, struct hostent **ret)
280 PARA_INFO_LOG("getting host info of %s\n", host);
281 /* FIXME: gethostbyname() is obsolete */
282 *ret = gethostbyname(host);
283 return *ret? 1 : -E_HOST_INFO;
287 * A wrapper around socket(2).
289 * \param domain The communication domain that selects the protocol family.
291 * \return The socket fd on success, -E_SOCKET on errors.
293 * Create an IPv4 socket for sequenced, reliable, two-way, connection-based
298 int get_stream_socket(int domain)
302 if ((socket_fd = socket(domain, SOCK_STREAM, 0)) == -1)
308 * paraslash's wrapper around the accept system call
310 * \param fd the listening socket
311 * \param addr structure which is filled in with the address of the peer socket
312 * \param size should contain the size of the structure pointed to by \a addr
314 * Accept incoming connections on \a addr. Retry if interrupted.
316 * \return The new file descriptor on success, \a -E_ACCEPT on errors.
320 int para_accept(int fd, void *addr, socklen_t size)
325 new_fd = accept(fd, (struct sockaddr *) addr, &size);
326 while (new_fd < 0 && errno == EINTR);
327 return new_fd < 0? -E_ACCEPT : new_fd;
330 static int setserversockopts(int socket_fd)
334 if (setsockopt(socket_fd, SOL_SOCKET, SO_REUSEADDR, &yes,
336 return -E_SETSOCKOPT;
341 * prepare a structure for \p AF_UNIX socket addresses
343 * \param u pointer to the struct to be prepared
344 * \param name the socket pathname
346 * This just copies \a name to the sun_path component of \a u.
348 * \return Positive on success, \p -E_NAME_TOO_LONG if \a name is longer
349 * than \p UNIX_PATH_MAX.
351 int init_unix_addr(struct sockaddr_un *u, const char *name)
353 if (strlen(name) >= UNIX_PATH_MAX)
354 return -E_NAME_TOO_LONG;
355 memset(u->sun_path, 0, UNIX_PATH_MAX);
356 u->sun_family = PF_UNIX;
357 strcpy(u->sun_path, name);
362 * Prepare, create, and bind a socket for local communication.
364 * \param name The socket pathname.
365 * \param unix_addr Pointer to the \p AF_UNIX socket structure.
366 * \param mode The desired mode of the socket.
368 * This functions creates a local socket for sequenced, reliable,
369 * two-way, connection-based byte streams.
371 * \return The file descriptor, on success, negative on errors.
377 int create_local_socket(const char *name, struct sockaddr_un *unix_addr,
382 ret = init_unix_addr(unix_addr, name);
385 fd = socket(PF_UNIX, SOCK_STREAM, 0);
389 if (bind(fd, (struct sockaddr *) unix_addr, UNIX_PATH_MAX) < 0)
392 if (chmod(name, mode) < 0)
401 ssize_t send_cred_buffer(int sock, char *buf)
403 return send_buffer(sock, buf);
405 int recv_cred_buffer(int fd, char *buf, size_t size)
407 return recv_buffer(fd, buf, size) > 0? 1 : -E_RECVMSG;
409 #else /* HAVE_UCRED */
411 * send NULL terminated buffer and Unix credentials of the current process
413 * \param sock the socket file descriptor
414 * \param buf the buffer to be sent
416 * \return On success, this call returns the number of characters sent. On
417 * error, \p -E_SENDMSG ist returned.
419 * \sa okir's Black Hats Manual
422 ssize_t send_cred_buffer(int sock, char *buf)
424 char control[sizeof(struct cmsghdr) + 10];
426 struct cmsghdr *cmsg;
427 static struct iovec iov;
433 iov.iov_len = strlen(buf);
437 /* compose the message */
438 memset(&msg, 0, sizeof(msg));
441 msg.msg_control = control;
442 msg.msg_controllen = sizeof(control);
443 /* attach the ucred struct */
444 cmsg = CMSG_FIRSTHDR(&msg);
445 cmsg->cmsg_level = SOL_SOCKET;
446 cmsg->cmsg_type = SCM_CREDENTIALS;
447 cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred));
448 *(struct ucred *)CMSG_DATA(cmsg) = c;
449 msg.msg_controllen = cmsg->cmsg_len;
450 ret = sendmsg(sock, &msg, 0);
456 static void dispose_fds(int *fds, unsigned num)
460 for (i = 0; i < num; i++)
465 * receive a buffer and the Unix credentials of the sending process
467 * \param fd the socket file descriptor
468 * \param buf the buffer to store the message
469 * \param size the size of \a buffer
471 * \return negative on errors, the user id on success.
473 * \sa okir's Black Hats Manual
476 int recv_cred_buffer(int fd, char *buf, size_t size)
480 struct cmsghdr *cmsg;
486 setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &yes, sizeof(int));
487 memset(&msg, 0, sizeof(msg));
488 memset(buf, 0, size);
493 msg.msg_control = control;
494 msg.msg_controllen = sizeof(control);
495 if (recvmsg(fd, &msg, 0) < 0)
497 result = -E_SCM_CREDENTIALS;
498 cmsg = CMSG_FIRSTHDR(&msg);
500 if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type
501 == SCM_CREDENTIALS) {
502 memcpy(&cred, CMSG_DATA(cmsg), sizeof(struct ucred));
505 if (cmsg->cmsg_level == SOL_SOCKET
506 && cmsg->cmsg_type == SCM_RIGHTS) {
507 dispose_fds((int *) CMSG_DATA(cmsg),
508 (cmsg->cmsg_len - CMSG_LEN(0))
511 cmsg = CMSG_NXTHDR(&msg, cmsg);
515 #endif /* HAVE_UCRED */
517 /** how many pending connections queue will hold */
521 * create a socket, bind it and listen
523 * \param port the tcp port to listen on
525 * \return The file descriptor of the created socket, negative
528 * \sa get_stream_socket()
533 int init_tcp_socket(int port)
535 struct sockaddr_in my_addr;
536 int fd, ret = get_stream_socket(AF_INET);
541 ret = setserversockopts(fd);
544 init_sockaddr(&my_addr, port, NULL);
546 if (bind(fd, (struct sockaddr *)&my_addr,
547 sizeof(struct sockaddr)) == -1) {
548 PARA_CRIT_LOG("bind error: %s\n", strerror(errno));
552 if (listen(fd, BACKLOG) == -1)
554 PARA_INFO_LOG("listening on port %d, fd %d\n", port, fd);
562 * receive a buffer and check for a pattern
564 * \param fd the file descriptor to receive from
565 * \param pattern the expected pattern
566 * \param bufsize the size of the internal buffer
568 * \return Positive if \a pattern was received, negative otherwise.
570 * This function creates a buffer of size \a bufsize and tries
571 * to receive at most \a bufsize bytes from file descriptor \a fd.
572 * If at least \p strlen(\a pattern) bytes were received, the beginning of
573 * the received buffer is compared with \a pattern, ignoring case.
578 int recv_pattern(int fd, const char *pattern, size_t bufsize)
580 size_t len = strlen(pattern);
581 char *buf = para_malloc(bufsize + 1);
582 int ret = -E_RECV_PATTERN, n = recv_buffer(fd, buf, bufsize);
586 if (strncasecmp(buf, pattern, len))
591 PARA_NOTICE_LOG("n = %d, did not receive pattern '%s'\n", n, pattern);
593 PARA_NOTICE_LOG("recvd: %s\n", buf);