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. */
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 necessary
127 * parameters. The interpretation of \a host depends on the value of \a passive:
128 * - on a passive socket host is interpreted as an interface IPv4/6 address
129 * (can be left NULL);
130 * - on an active socket, \a host is the peer DNS name or IPv4/6 address to connect to;
131 * - \a port_number is in either case the numeric port number (not service string).
132 * Furthermore, bind(2) is called on passive sockets, and connect(2) on active sockets.
133 * The algorithm tries all possible address combinations until it succeeds.
135 * \return This function returns 1 on success and \a -E_ADDRESS_LOOKUP when no matching
136 * connection could be set up (with details in the error log).
138 * \sa ipv6(7), getaddrinfo(3), bind(2), connect(2)
140 int makesock(unsigned l3type, unsigned l4type, int passive,
141 const char *host, unsigned short port_number)
143 struct addrinfo *local = NULL, *src,
144 *remote = NULL, *dst, hints;
145 char *port = make_message("%u", port_number);
146 int rc, on = 1, sockfd = -1,
147 socktype = sock_type(l4type);
150 * Set up address hint structure
152 memset(&hints, 0, sizeof(hints));
153 hints.ai_family = l3type;
154 /* getaddrinfo does not really work well with SOCK_DCCP */
155 if (socktype == SOCK_DGRAM || socktype == SOCK_STREAM)
156 hints.ai_socktype = socktype;
158 /* only use addresses available on the host */
159 hints.ai_flags = AI_ADDRCONFIG;
160 if (l3type == AF_INET6)
161 /* use v4-mapped-v6 if no v6 addresses found */
162 hints.ai_flags |= AI_V4MAPPED | AI_ALL;
164 if (passive && host == NULL)
165 hints.ai_flags |= AI_PASSIVE;
168 * Obtain local/remote address information
170 if ((rc = getaddrinfo(host, port, &hints, passive ? &local : &remote))) {
171 PARA_ERROR_LOG("can not resolve %s address %s#%s: %s.\n",
173 host? : (passive? "[loopback]" : "[localhost]"),
174 port, gai_strerror(rc));
175 return -E_ADDRESS_LOOKUP;
179 * 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) /* v4 -> v6 is not possible */
186 sockfd = socket(src ? src->ai_family : dst->ai_family, socktype, l4type);
191 * Set those options that need to be set before establishing the connection
193 /* Reuse the address on passive (listening) sockets to avoid failure on restart */
194 if (passive && setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1) {
195 PARA_ERROR_LOG("can not set SO_REUSEADDR: %s\n", strerror(errno));
196 return -ERRNO_TO_PARA_ERROR(errno);
200 if (bind(sockfd, src->ai_addr, src->ai_addrlen) < 0) {
205 break; /* bind-only completed successfully */
208 if (dst && connect(sockfd, dst->ai_addr, dst->ai_addrlen) == 0)
209 break; /* connection completed successfully */
212 if (dst && (dst = dst->ai_next))
215 if (src && (src = src->ai_next))
216 dst = remote; /* restart inner loop */
221 freeaddrinfo(remote);
223 if (src == NULL && dst == NULL) {
224 PARA_ERROR_LOG("can not create %s socket %s#%s.\n", layer4_name(l4type),
225 host? : (passive? "[loopback]" : "[localhost]"), port);
226 return -ERRNO_TO_PARA_ERROR(errno);
232 * Create a passive / listening socket.
233 * \param l3type The network-layer type (\p AF_xxx)
234 * \param l4type The transport-layer type (\p IPPROTO_xxx).
235 * \param port The decimal port number to listen on.
237 * \return Positive integer (socket descriptor) on success, negative value otherwise.
238 * \sa makesock(), ip(7), ipv6(7), bind(2), listen(2).
240 int para_listen(unsigned l3type, unsigned l4type, unsigned short port)
242 int ret, fd = makesock(l3type, l4type, 1, NULL, port);
245 ret = listen(fd, BACKLOG);
248 return -ERRNO_TO_PARA_ERROR(errno);
250 PARA_INFO_LOG("listening on %s port %u, fd %d\n",
251 layer4_name(l4type), port, fd);
257 * Print numeric host and port number (beware - uses static char).
258 * \param sa The IPv4/IPv6 socket address to use.
259 * \param len The length of \p sa.
263 char *host_and_port(struct sockaddr *sa, socklen_t len)
265 static char output[NI_MAXHOST + NI_MAXSERV + 2];
266 char hbuf[NI_MAXHOST],
270 ret = getnameinfo(sa, len, hbuf, sizeof(hbuf), sbuf, sizeof(sbuf),
271 NI_NUMERICHOST | NI_NUMERICSERV);
273 PARA_WARNING_LOG("hostname lookup error (%s).\n", gai_strerror(ret));
274 sprintf(output, "(unknown)");
276 sprintf(output, "%s#%s", hbuf, sbuf);
282 * Look up the local or remote side of a connected socket structure.
283 * \param fd The socket descriptor of the connected socket.
284 * \param getname Either \fn getsockname() for local, or \fn getpeername() for remote side.
286 * \return A static character string identifying hostname and port of the chosen side
287 * \sa getsockname(2), getpeername(2)
289 static char *__get_sock_name(int fd, int (*getname)(int, struct sockaddr*, socklen_t *))
291 struct sockaddr_storage ss;
292 socklen_t sslen = sizeof(ss);
294 if (getname(fd, (struct sockaddr *)&ss, &sslen) < 0) {
295 static char *dont_know = "(don't know)";
296 PARA_ERROR_LOG("can not determine address from fd %d: %s\n", fd, strerror(errno));
300 return host_and_port((struct sockaddr *)&ss, sslen);
303 char *local_name(int sockfd)
305 return __get_sock_name(sockfd, getsockname);
308 char *remote_name(int sockfd)
310 return __get_sock_name(sockfd, getpeername);
314 * Send out a buffer, resend on short writes.
316 * \param fd The file descriptor.
317 * \param buf The buffer to be sent.
318 * \param len The length of \a buf.
320 * \return Standard. In any case, the number of bytes actually sent is stored
323 static int sendall(int fd, const char *buf, size_t *len)
329 while (*len < total) {
330 int ret = send(fd, buf + *len, total - *len, 0);
332 return -ERRNO_TO_PARA_ERROR(errno);
339 * Encrypt and send a binary buffer.
341 * \param fd The file descriptor.
342 * \param buf The buffer to be encrypted and sent.
343 * \param len The length of \a buf.
345 * Check if encryption is available. If yes, encrypt the given buffer. Send
346 * out the buffer, encrypted or not, and try to resend the remaing part in case
351 int send_bin_buffer(int fd, const char *buf, size_t len)
354 crypt_function *cf = NULL;
357 PARA_CRIT_LOG("%s", "len == 0\n");
358 if (fd + 1 <= cda_size)
359 cf = crypt_data_array[fd].send;
361 void *private = crypt_data_array[fd].private_data;
362 /* RC4 may write more than len to the output buffer */
363 unsigned char *outbuf = para_malloc(ROUND_UP(len, 8));
364 (*cf)(len, (unsigned char *)buf, outbuf, private);
365 ret = sendall(fd, (char *)outbuf, &len);
368 ret = sendall(fd, buf, &len);
373 * Encrypt and send null terminated buffer.
375 * \param fd The file descriptor.
376 * \param buf The null-terminated buffer to be send.
378 * This is equivalent to send_bin_buffer(fd, buf, strlen(buf)).
382 int send_buffer(int fd, const char *buf)
384 return send_bin_buffer(fd, buf, strlen(buf));
389 * Send and encrypt a buffer given by a format string.
391 * \param fd The file descriptor.
392 * \param fmt A format string.
396 __printf_2_3 int send_va_buffer(int fd, const char *fmt, ...)
401 PARA_VSPRINTF(fmt, msg);
402 ret = send_buffer(fd, msg);
408 * Receive and decrypt.
410 * \param fd The file descriptor.
411 * \param buf The buffer to write the decrypted data to.
412 * \param size The size of \a buf.
414 * Receive at most \a size bytes from file descriptor \a fd. If encryption is
415 * available, decrypt the received buffer.
417 * \return The number of bytes received on success, negative on errors.
421 __must_check int recv_bin_buffer(int fd, char *buf, size_t size)
424 crypt_function *cf = NULL;
426 if (fd + 1 <= cda_size)
427 cf = crypt_data_array[fd].recv;
429 unsigned char *tmp = para_malloc(size);
430 void *private = crypt_data_array[fd].private_data;
431 n = recv(fd, tmp, size, 0);
434 unsigned char *b = (unsigned char *)buf;
435 (*cf)(numbytes, tmp, b, private);
439 n = recv(fd, buf, size, 0);
441 return -ERRNO_TO_PARA_ERROR(errno);
446 * Receive, decrypt and write terminating NULL byte.
448 * \param fd The file descriptor.
449 * \param buf The buffer to write the decrypted data to.
450 * \param size The size of \a buf.
452 * Read and decrypt at most \a size - 1 bytes from file descriptor \a fd and
453 * write a NULL byte at the end of the received data.
455 * \return The return value of the underlying call to \a recv_bin_buffer().
457 * \sa recv_bin_buffer()
459 int recv_buffer(int fd, char *buf, size_t size)
464 n = recv_bin_buffer(fd, buf, size - 1);
473 * Wrapper around the accept system call.
475 * \param fd The listening socket.
476 * \param addr Structure which is filled in with the address of the peer socket.
477 * \param size Should contain the size of the structure pointed to by \a addr.
479 * Accept incoming connections on \a addr. Retry if interrupted.
481 * \return The new file descriptor on success, negative on errors.
485 int para_accept(int fd, void *addr, socklen_t size)
490 new_fd = accept(fd, (struct sockaddr *) addr, &size);
491 while (new_fd < 0 && errno == EINTR);
492 return new_fd < 0? -ERRNO_TO_PARA_ERROR(errno) : new_fd;
496 * prepare a structure for \p AF_UNIX socket addresses
498 * \param u pointer to the struct to be prepared
499 * \param name the socket pathname
501 * This just copies \a name to the sun_path component of \a u.
503 * \return Positive on success, \p -E_NAME_TOO_LONG if \a name is longer
504 * than \p UNIX_PATH_MAX.
506 static int init_unix_addr(struct sockaddr_un *u, const char *name)
508 if (strlen(name) >= UNIX_PATH_MAX)
509 return -E_NAME_TOO_LONG;
510 memset(u->sun_path, 0, UNIX_PATH_MAX);
511 u->sun_family = PF_UNIX;
512 strcpy(u->sun_path, name);
517 * Prepare, create, and bind a socket for local communication.
519 * \param name The socket pathname.
520 * \param unix_addr Pointer to the \p AF_UNIX socket structure.
521 * \param mode The desired mode of the socket.
523 * This function creates a local socket for sequenced, reliable,
524 * two-way, connection-based byte streams.
526 * \return The file descriptor, on success, negative on errors.
532 int create_local_socket(const char *name, struct sockaddr_un *unix_addr,
537 ret = init_unix_addr(unix_addr, name);
540 ret = socket(PF_UNIX, SOCK_STREAM, 0);
542 return -ERRNO_TO_PARA_ERROR(errno);
544 ret = bind(fd, (struct sockaddr *) unix_addr, UNIX_PATH_MAX);
546 ret = -ERRNO_TO_PARA_ERROR(errno);
550 if (chmod(name, mode) < 0)
559 * Prepare, create, and connect to a Unix domain socket for local communication.
561 * \param name The socket pathname.
563 * This function creates a local socket for sequenced, reliable, two-way,
564 * connection-based byte streams.
566 * \return The file descriptor, on success, negative on errors.
568 * \sa create_local_socket(), unix(7), connect(2)
570 int create_remote_socket(const char *name)
572 struct sockaddr_un unix_addr;
575 ret = init_unix_addr(&unix_addr, name);
578 fd = socket(PF_UNIX, SOCK_STREAM, 0);
580 return -ERRNO_TO_PARA_ERROR(errno);
581 if (connect(fd, (struct sockaddr *)&unix_addr, sizeof(unix_addr)) == -1) {
582 ret = -ERRNO_TO_PARA_ERROR(errno);
592 ssize_t send_cred_buffer(int sock, char *buf)
594 return send_buffer(sock, buf);
596 int recv_cred_buffer(int fd, char *buf, size_t size)
598 return recv_buffer(fd, buf, size) > 0? 1 : -E_RECVMSG;
600 #else /* HAVE_UCRED */
602 * send NULL terminated buffer and Unix credentials of the current process
604 * \param sock the socket file descriptor
605 * \param buf the buffer to be sent
607 * \return On success, this call returns the number of characters sent. On
608 * error, \p -E_SENDMSG is returned.
610 * \sa okir's Black Hats Manual
613 ssize_t send_cred_buffer(int sock, char *buf)
615 char control[sizeof(struct cmsghdr) + 10];
617 struct cmsghdr *cmsg;
618 static struct iovec iov;
624 iov.iov_len = strlen(buf);
628 /* compose the message */
629 memset(&msg, 0, sizeof(msg));
632 msg.msg_control = control;
633 msg.msg_controllen = sizeof(control);
634 /* attach the ucred struct */
635 cmsg = CMSG_FIRSTHDR(&msg);
636 cmsg->cmsg_level = SOL_SOCKET;
637 cmsg->cmsg_type = SCM_CREDENTIALS;
638 cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred));
639 *(struct ucred *)CMSG_DATA(cmsg) = c;
640 msg.msg_controllen = cmsg->cmsg_len;
641 ret = sendmsg(sock, &msg, 0);
647 static void dispose_fds(int *fds, unsigned num)
651 for (i = 0; i < num; i++)
656 * receive a buffer and the Unix credentials of the sending process
658 * \param fd the socket file descriptor
659 * \param buf the buffer to store the message
660 * \param size the size of \a buffer
662 * \return negative on errors, the user id on success.
664 * \sa okir's Black Hats Manual
667 int recv_cred_buffer(int fd, char *buf, size_t size)
671 struct cmsghdr *cmsg;
677 setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &yes, sizeof(int));
678 memset(&msg, 0, sizeof(msg));
679 memset(buf, 0, size);
684 msg.msg_control = control;
685 msg.msg_controllen = sizeof(control);
686 if (recvmsg(fd, &msg, 0) < 0)
688 result = -E_SCM_CREDENTIALS;
689 cmsg = CMSG_FIRSTHDR(&msg);
691 if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type
692 == SCM_CREDENTIALS) {
693 memcpy(&cred, CMSG_DATA(cmsg), sizeof(struct ucred));
696 if (cmsg->cmsg_level == SOL_SOCKET
697 && cmsg->cmsg_type == SCM_RIGHTS) {
698 dispose_fds((int *) CMSG_DATA(cmsg),
699 (cmsg->cmsg_len - CMSG_LEN(0))
702 cmsg = CMSG_NXTHDR(&msg, cmsg);
706 #endif /* HAVE_UCRED */
709 * receive a buffer and check for a pattern
711 * \param fd the file descriptor to receive from
712 * \param pattern the expected pattern
713 * \param bufsize the size of the internal buffer
715 * \return Positive if \a pattern was received, negative otherwise.
717 * This function creates a buffer of size \a bufsize and tries
718 * to receive at most \a bufsize bytes from file descriptor \a fd.
719 * If at least \p strlen(\a pattern) bytes were received, the beginning of
720 * the received buffer is compared with \a pattern, ignoring case.
725 int recv_pattern(int fd, const char *pattern, size_t bufsize)
727 size_t len = strlen(pattern);
728 char *buf = para_malloc(bufsize + 1);
729 int ret = -E_RECV_PATTERN, n = recv_buffer(fd, buf, bufsize);
733 if (strncasecmp(buf, pattern, len))
738 PARA_NOTICE_LOG("n = %d, did not receive pattern '%s'\n", n, pattern);
740 PARA_NOTICE_LOG("recvd: %s\n", buf);