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
31 /** Information about one encrypted connection. */
33 /** Function used to decrypt received data. */
35 /** Function used to encrypt data to be sent. */
38 * Context-dependent data (crypt keys), passed verbatim to the above
43 /** Array holding per fd crypt data. */
44 static struct crypt_data *crypt_data_array;
45 /** Current size of the crypt data array. */
46 static unsigned cda_size = 0;
49 * Activate encryption for one file descriptor.
51 * \param fd The file descriptor.
52 * \param recv_f The function used for decrypting received data.
53 * \param send_f The function used for encrypting before sending.
54 * \param private_data User data supplied by the caller.
56 void enable_crypt(int fd, crypt_function *recv_f, crypt_function *send_f,
59 if (fd + 1 > cda_size) {
60 crypt_data_array = para_realloc(crypt_data_array,
61 (fd + 1) * sizeof(struct crypt_data));
62 memset(crypt_data_array + cda_size, 0,
63 (fd + 1 - cda_size) * sizeof(struct crypt_data));
66 crypt_data_array[fd].recv = recv_f;
67 crypt_data_array[fd].send = send_f;
68 crypt_data_array[fd].private_data = private_data;
69 PARA_INFO_LOG("rc4 encryption activated for fd %d\n", fd);
73 * Deactivate encryption for a given fd.
75 * \param fd The file descriptor.
77 * This must be called if and only if \p fd was activated via enable_crypt().
79 void disable_crypt(int fd)
81 if (cda_size < fd + 1)
83 crypt_data_array[fd].recv = NULL;
84 crypt_data_array[fd].send = NULL;
85 crypt_data_array[fd].private_data = NULL;
90 * Determine the socket type for a given layer-4 protocol.
92 * \param l4type The symbolic name of the transport-layer protocol.
94 * \sa ip(7), socket(2)
96 static inline int sock_type(const unsigned l4type)
99 case IPPROTO_UDP: return SOCK_DGRAM;
100 case IPPROTO_TCP: return SOCK_STREAM;
101 case IPPROTO_DCCP: return SOCK_DCCP;
103 return -1; /* not supported here */
107 * Pretty-print transport-layer name.
109 static const char *layer4_name(const unsigned l4type)
112 case IPPROTO_UDP: return "UDP";
113 case IPPROTO_TCP: return "TCP";
114 case IPPROTO_DCCP: return "DCCP";
116 return "UNKNOWN PROTOCOL";
120 * Resolve IPv4/IPv6 address and create a ready-to-use active or passive socket.
122 * \param l3type The layer-3 type (\p AF_INET, \p AF_INET6, \p AF_UNSPEC).
123 * \param l4type The layer-4 type (\p IPPROTO_xxx).
124 * \param passive Whether this is a passive (1) or active (0) socket.
125 * \param host Remote or local hostname or IPv/6 address string.
126 * \param port_number Decimal port number.
128 * This creates a ready-made IPv4/v6 socket structure after looking up the
129 * necessary parameters. The interpretation of \a host depends on the value of
131 * - on a passive socket host is interpreted as an interface IPv4/6 address
132 * (can be left NULL);
133 * - on an active socket, \a host is the peer DNS name or IPv4/6 address
135 * - \a port_number is in either case the numeric port number (not service
138 * Furthermore, bind(2) is called on passive sockets, and connect(2) on active
139 * sockets. The algorithm tries all possible address combinations until it
142 * \return This function returns 1 on success and \a -E_ADDRESS_LOOKUP when no
143 * matching connection could be set up (with details in the error log).
145 * \sa ipv6(7), getaddrinfo(3), bind(2), connect(2).
147 int makesock(unsigned l3type, unsigned l4type, int passive,
148 const char *host, unsigned short port_number)
150 struct addrinfo *local = NULL, *src,
151 *remote = NULL, *dst, hints;
152 int rc, on = 1, sockfd = -1,
153 socktype = sock_type(l4type);
154 char port[6]; /* port number has at most 5 digits */
156 sprintf(port, "%u", port_number);
157 /* Set up address hint structure */
158 memset(&hints, 0, sizeof(hints));
159 hints.ai_family = l3type;
160 hints.ai_socktype = socktype;
162 * getaddrinfo does not support SOCK_DCCP, so for the sake of lookup
163 * (and only then) pretend to be UDP.
165 if (l4type == IPPROTO_DCCP)
166 hints.ai_socktype = SOCK_DGRAM;
168 /* only use addresses available on the host */
169 hints.ai_flags = AI_ADDRCONFIG;
170 if (l3type == AF_INET6)
171 /* use v4-mapped-v6 if no v6 addresses found */
172 hints.ai_flags |= AI_V4MAPPED | AI_ALL;
174 if (passive && host == NULL)
175 hints.ai_flags |= AI_PASSIVE;
177 /* Obtain local/remote address information */
178 if ((rc = getaddrinfo(host, port, &hints, passive ? &local : &remote))) {
179 PARA_ERROR_LOG("can not resolve %s address %s#%s: %s.\n",
181 host? host : (passive? "[loopback]" : "[localhost]"),
182 port, gai_strerror(rc));
183 return -E_ADDRESS_LOOKUP;
186 /* Iterate over all src/dst combination, exhausting dst first */
187 for (src = local, dst = remote; src != NULL || dst != NULL; /* no op */ ) {
188 if (src && dst && src->ai_family == AF_INET
189 && dst->ai_family == AF_INET6)
190 goto get_next_dst; /* v4 -> v6 is not possible */
192 sockfd = socket(src ? src->ai_family : dst->ai_family,
198 * Set those options that need to be set before establishing
199 * the connection. Reuse the address on passive (listening)
200 * sockets to avoid failure on restart.
202 if (passive && setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
203 &on, sizeof(on)) == -1) {
204 PARA_ERROR_LOG("can not set SO_REUSEADDR: %s\n",
206 return -ERRNO_TO_PARA_ERROR(errno);
210 if (bind(sockfd, src->ai_addr, src->ai_addrlen) < 0) {
214 if (!dst) /* bind-only completed successfully */
218 if (dst && connect(sockfd, dst->ai_addr, dst->ai_addrlen) == 0)
219 break; /* connection completed successfully */
222 if (dst && (dst = dst->ai_next))
225 if (src && (src = src->ai_next)) /* restart inner loop */
231 freeaddrinfo(remote);
233 if (src == NULL && dst == NULL) {
234 PARA_ERROR_LOG("can not create %s socket %s#%s.\n",
235 layer4_name(l4type), host? host : (passive?
236 "[loopback]" : "[localhost]"), port);
237 return -ERRNO_TO_PARA_ERROR(errno);
243 * Create a passive / listening socket.
245 * \param l3type The network-layer type (\p AF_xxx).
246 * \param l4type The transport-layer type (\p IPPROTO_xxx).
247 * \param port The decimal port number to listen on.
249 * \return Positive integer (socket descriptor) on success, negative value
252 * \sa makesock(), ip(7), ipv6(7), bind(2), listen(2).
254 int para_listen(unsigned l3type, unsigned l4type, unsigned short port)
256 int ret, fd = makesock(l3type, l4type, 1, NULL, port);
259 ret = listen(fd, BACKLOG);
262 return -ERRNO_TO_PARA_ERROR(errno);
264 PARA_INFO_LOG("listening on %s port %u, fd %d\n",
265 layer4_name(l4type), port, fd);
271 * Print numeric host and port number (beware - uses static char).
273 * \param sa The IPv4/IPv6 socket address to use.
274 * \param len The length of \p sa.
276 * \sa getnameinfo(3).
278 static char *host_and_port(struct sockaddr *sa, socklen_t len)
280 static char output[NI_MAXHOST + NI_MAXSERV + 2];
281 char hbuf[NI_MAXHOST], sbuf[NI_MAXSERV];
284 ret = getnameinfo(sa, len, hbuf, sizeof(hbuf), sbuf, sizeof(sbuf),
285 NI_NUMERICHOST | NI_NUMERICSERV);
287 PARA_WARNING_LOG("hostname lookup error (%s).\n",
289 sprintf(output, "(unknown)");
291 sprintf(output, "%s#%s", hbuf, sbuf);
296 * Look up the local or remote side of a connected socket structure.
298 * \param fd The socket descriptor of the connected socket.
299 * \param getname Either \p getsockname() for local, or \p getpeername() for
302 * \return A static character string identifying hostname and port of the
305 * \sa getsockname(2), getpeername(2).
307 static char *__get_sock_name(int fd, int (*getname)(int, struct sockaddr*,
310 struct sockaddr_storage ss;
311 socklen_t sslen = sizeof(ss);
313 if (getname(fd, (struct sockaddr *)&ss, &sslen) < 0) {
314 static char *dont_know = "(don't know)";
315 PARA_ERROR_LOG("can not determine address from fd %d: %s\n",
316 fd, strerror(errno));
319 return host_and_port((struct sockaddr *)&ss, sslen);
322 char *local_name(int sockfd)
324 return __get_sock_name(sockfd, getsockname);
327 char *remote_name(int sockfd)
329 return __get_sock_name(sockfd, getpeername);
333 * Extract IPv4 or IPv6-mapped-IPv4 address from sockaddr_storage.
334 * \param ss Container of IPv4/6 address
335 * \return Extracted IPv4 address (different from 0) or 0 if unsuccessful.
339 struct in_addr extract_v4_addr(const struct sockaddr_storage *ss)
341 struct in_addr ia = {.s_addr = 0};
343 if (ss->ss_family == AF_INET)
344 ia.s_addr = ((struct sockaddr_in *)ss)->sin_addr.s_addr;
345 if (ss->ss_family == AF_INET6) {
346 const struct in6_addr v6_addr = ((struct sockaddr_in6 *)ss)->sin6_addr;
348 if (IN6_IS_ADDR_V4MAPPED(&v6_addr))
349 memcpy(&ia.s_addr, &(v6_addr.s6_addr[12]), 4);
355 * Encrypt and send a binary buffer.
357 * \param fd The file descriptor.
358 * \param buf The buffer to be encrypted and sent.
359 * \param len The length of \a buf.
361 * Check if encryption is available. If yes, encrypt the given buffer. Send
362 * out the buffer, encrypted or not, and try to resend the remaing part in case
367 int send_bin_buffer(int fd, const char *buf, size_t len)
370 crypt_function *cf = NULL;
373 PARA_CRIT_LOG("len == 0\n");
374 if (fd + 1 <= cda_size)
375 cf = crypt_data_array[fd].send;
377 void *private = crypt_data_array[fd].private_data;
378 /* RC4 may write more than len to the output buffer */
379 unsigned char *outbuf = para_malloc(ROUND_UP(len, 8));
380 (*cf)(len, (unsigned char *)buf, outbuf, private);
381 ret = write_all(fd, (char *)outbuf, &len);
384 ret = write_all(fd, buf, &len);
389 * Encrypt and send null terminated buffer.
391 * \param fd The file descriptor.
392 * \param buf The null-terminated buffer to be send.
394 * This is equivalent to send_bin_buffer(fd, buf, strlen(buf)).
398 int send_buffer(int fd, const char *buf)
400 return send_bin_buffer(fd, buf, strlen(buf));
405 * Send and encrypt a buffer given by a format string.
407 * \param fd The file descriptor.
408 * \param fmt A format string.
412 __printf_2_3 int send_va_buffer(int fd, const char *fmt, ...)
417 PARA_VSPRINTF(fmt, msg);
418 ret = send_buffer(fd, msg);
424 * Receive and decrypt.
426 * \param fd The file descriptor.
427 * \param buf The buffer to write the decrypted data to.
428 * \param size The size of \a buf.
430 * Receive at most \a size bytes from file descriptor \a fd. If encryption is
431 * available, decrypt the received buffer.
433 * \return The number of bytes received on success, negative on errors.
437 __must_check int recv_bin_buffer(int fd, char *buf, size_t size)
440 crypt_function *cf = NULL;
442 if (fd + 1 <= cda_size)
443 cf = crypt_data_array[fd].recv;
445 unsigned char *tmp = para_malloc(size);
446 void *private = crypt_data_array[fd].private_data;
447 n = recv(fd, tmp, size, 0);
450 unsigned char *b = (unsigned char *)buf;
451 (*cf)(numbytes, tmp, b, private);
455 n = recv(fd, buf, size, 0);
457 return -ERRNO_TO_PARA_ERROR(errno);
462 * Receive, decrypt and write terminating NULL byte.
464 * \param fd The file descriptor.
465 * \param buf The buffer to write the decrypted data to.
466 * \param size The size of \a buf.
468 * Read and decrypt at most \a size - 1 bytes from file descriptor \a fd and
469 * write a NULL byte at the end of the received data.
471 * \return The return value of the underlying call to \a recv_bin_buffer().
473 * \sa recv_bin_buffer()
475 int recv_buffer(int fd, char *buf, size_t size)
480 n = recv_bin_buffer(fd, buf, size - 1);
489 * Wrapper around the accept system call.
491 * \param fd The listening socket.
492 * \param addr Structure which is filled in with the address of the peer socket.
493 * \param size Should contain the size of the structure pointed to by \a addr.
495 * Accept incoming connections on \a addr. Retry if interrupted.
497 * \return The new file descriptor on success, negative on errors.
501 int para_accept(int fd, void *addr, socklen_t size)
506 new_fd = accept(fd, (struct sockaddr *) addr, &size);
507 while (new_fd < 0 && errno == EINTR);
508 return new_fd < 0? -ERRNO_TO_PARA_ERROR(errno) : new_fd;
512 * Prepare a structure for \p AF_UNIX socket addresses.
514 * \param u Pointer to the struct to be prepared.
515 * \param name The socket pathname.
517 * This just copies \a name to the sun_path component of \a u.
519 * \return Positive on success, \p -E_NAME_TOO_LONG if \a name is longer
520 * than \p UNIX_PATH_MAX.
522 static int init_unix_addr(struct sockaddr_un *u, const char *name)
524 if (strlen(name) >= UNIX_PATH_MAX)
525 return -E_NAME_TOO_LONG;
526 memset(u->sun_path, 0, UNIX_PATH_MAX);
527 u->sun_family = PF_UNIX;
528 strcpy(u->sun_path, name);
533 * Prepare, create, and bind a socket for local communication.
535 * \param name The socket pathname.
536 * \param unix_addr Pointer to the \p AF_UNIX socket structure.
537 * \param mode The desired mode of the socket.
539 * This function creates a local socket for sequenced, reliable,
540 * two-way, connection-based byte streams.
542 * \return The file descriptor, on success, negative on errors.
548 int create_local_socket(const char *name, struct sockaddr_un *unix_addr,
553 ret = init_unix_addr(unix_addr, name);
556 ret = socket(PF_UNIX, SOCK_STREAM, 0);
558 return -ERRNO_TO_PARA_ERROR(errno);
560 ret = bind(fd, (struct sockaddr *) unix_addr, UNIX_PATH_MAX);
562 ret = -ERRNO_TO_PARA_ERROR(errno);
566 if (chmod(name, mode) < 0)
575 * Prepare, create, and connect to a Unix domain socket for local communication.
577 * \param name The socket pathname.
579 * This function creates a local socket for sequenced, reliable, two-way,
580 * connection-based byte streams.
582 * \return The file descriptor, on success, negative on errors.
584 * \sa create_local_socket(), unix(7), connect(2).
586 int create_remote_socket(const char *name)
588 struct sockaddr_un unix_addr;
591 ret = init_unix_addr(&unix_addr, name);
594 fd = socket(PF_UNIX, SOCK_STREAM, 0);
596 return -ERRNO_TO_PARA_ERROR(errno);
597 if (connect(fd, (struct sockaddr *)&unix_addr, sizeof(unix_addr)) == -1) {
598 ret = -ERRNO_TO_PARA_ERROR(errno);
608 ssize_t send_cred_buffer(int sock, char *buf)
610 return send_buffer(sock, buf);
612 int recv_cred_buffer(int fd, char *buf, size_t size)
614 return recv_buffer(fd, buf, size) > 0? 1 : -E_RECVMSG;
616 #else /* HAVE_UCRED */
618 * Send \p NULL-terminated buffer and Unix credentials of the current process.
620 * \param sock The socket file descriptor.
621 * \param buf The buffer to be sent.
623 * \return On success, this call returns the number of characters sent. On
624 * error, \p -E_SENDMSG is returned.
626 * \sa sendmsg(2), okir's Black Hats Manual.
628 ssize_t send_cred_buffer(int sock, char *buf)
630 char control[sizeof(struct cmsghdr) + 10];
632 struct cmsghdr *cmsg;
633 static struct iovec iov;
639 iov.iov_len = strlen(buf);
643 /* compose the message */
644 memset(&msg, 0, sizeof(msg));
647 msg.msg_control = control;
648 msg.msg_controllen = sizeof(control);
649 /* attach the ucred struct */
650 cmsg = CMSG_FIRSTHDR(&msg);
651 cmsg->cmsg_level = SOL_SOCKET;
652 cmsg->cmsg_type = SCM_CREDENTIALS;
653 cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred));
654 *(struct ucred *)CMSG_DATA(cmsg) = c;
655 msg.msg_controllen = cmsg->cmsg_len;
656 ret = sendmsg(sock, &msg, 0);
662 static void dispose_fds(int *fds, unsigned num)
666 for (i = 0; i < num; i++)
671 * Receive a buffer and the Unix credentials of the sending process.
673 * \param fd the socket file descriptor.
674 * \param buf the buffer to store the message.
675 * \param size the size of \a buffer.
677 * \return negative on errors, the user id on success.
679 * \sa recvmsg(2), okir's Black Hats Manual.
681 int recv_cred_buffer(int fd, char *buf, size_t size)
685 struct cmsghdr *cmsg;
691 setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &yes, sizeof(int));
692 memset(&msg, 0, sizeof(msg));
693 memset(buf, 0, size);
698 msg.msg_control = control;
699 msg.msg_controllen = sizeof(control);
700 if (recvmsg(fd, &msg, 0) < 0)
702 result = -E_SCM_CREDENTIALS;
703 cmsg = CMSG_FIRSTHDR(&msg);
705 if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type
706 == SCM_CREDENTIALS) {
707 memcpy(&cred, CMSG_DATA(cmsg), sizeof(struct ucred));
710 if (cmsg->cmsg_level == SOL_SOCKET
711 && cmsg->cmsg_type == SCM_RIGHTS) {
712 dispose_fds((int *) CMSG_DATA(cmsg),
713 (cmsg->cmsg_len - CMSG_LEN(0))
716 cmsg = CMSG_NXTHDR(&msg, cmsg);
720 #endif /* HAVE_UCRED */
723 * Receive a buffer and check for a pattern.
725 * \param fd The file descriptor to receive from.
726 * \param pattern The expected pattern.
727 * \param bufsize The size of the internal buffer.
729 * \return Positive if \a pattern was received, negative otherwise.
731 * This function creates a buffer of size \a bufsize and tries
732 * to receive at most \a bufsize bytes from file descriptor \a fd.
733 * If at least \p strlen(\a pattern) bytes were received, the beginning of
734 * the received buffer is compared with \a pattern, ignoring case.
736 * \sa recv_buffer(), \sa strncasecmp(3).
738 int recv_pattern(int fd, const char *pattern, size_t bufsize)
740 size_t len = strlen(pattern);
741 char *buf = para_malloc(bufsize + 1);
742 int ret = -E_RECV_PATTERN, n = recv_buffer(fd, buf, bufsize);
746 if (strncasecmp(buf, pattern, len))
751 PARA_NOTICE_LOG("n = %d, did not receive pattern '%s'\n", n,
754 PARA_NOTICE_LOG("recvd: %s\n", buf);