2 * Copyright (C) 2005-2009 Andre Noll <maan@systemlinux.org>
4 * Licensed under the GPL v2. For licencing details see COPYING.
7 /** \file net.c Networking-related helper functions. */
10 * Since glibc 2.8, the _GNU_SOURCE feature test macro must be defined in order
11 * to obtain the definition of the ucred structure.
17 /* At least NetBSD needs these. */
25 #define AI_ADDRCONFIG 0
30 #include <openssl/rc4.h>
40 * Parse and validate IPv4 address/netmask string.
42 * \param cidr Address in CIDR notation
43 * \param addr Copy of the IPv4 address part of \a cidr
44 * \param addrlen Size of \a addr in bytes
45 * \param netmask Value of the netmask part in \a cidr or the
46 * default of 32 if not specified.
48 * \return Pointer to \a addr if succesful, NULL on error.
51 char *parse_cidr(const char *cidr,
52 char *addr, ssize_t addrlen,
56 char *c = addr, *end = c + (addrlen - 1);
60 if (cidr == NULL || addrlen < 1)
63 for (o = cidr; (*c = *o == '/'? '\0' : *o); c++, o++)
68 if (para_atoi32(++o, netmask) < 0 ||
69 *netmask < 0 || *netmask > 0x20)
72 if (is_valid_ipv4_address(addr))
81 * Match string as a candidate IPv4 address.
83 * \param address The string to match.
84 * \return True if \a address has "dot-quad" format.
86 static bool is_v4_dot_quad(const char *address)
91 assert(!regcomp(&r, "^([0-9]+\\.){3}[0-9]+$", REG_EXTENDED|REG_NOSUB));
92 result = regexec(&r, address, 0, NULL, 0) == 0;
98 * Perform basic syntax checking on the host-part of an URL:
100 * - Since ':' is invalid in IPv4 addresses and DNS names, the
101 * presence of ':' causes interpretation as IPv6 address;
102 * - next the first-match-wins algorithm from RFC 3986 is applied;
103 * - else the string is considered as DNS name, to be resolved later.
105 * \param host The host string to check.
106 * \return True if \a host passes the syntax checks.
108 * \sa RFC 3986, 3.2.2; RFC 1123, 2.1; RFC 1034, 3.5
110 static bool host_string_ok(const char *host)
112 if (host == NULL || *host == '\0')
114 if (strchr(host, ':') != NULL)
115 return is_valid_ipv6_address(host);
116 if (is_v4_dot_quad(host))
117 return is_valid_ipv4_address(host);
122 * Parse and validate URL string.
124 * The URL syntax is loosely based on RFC 3986, supporting one of
125 * - "["host"]"[:port] for native IPv6 addresses and
126 * - host[:port] for IPv4 hostnames and DNS names.
128 * Native IPv6 addresses must be enclosed in square brackets, since
129 * otherwise there is an ambiguity with the port separator `:'.
130 * The 'port' part is always considered to be a number; if absent,
131 * it is set to -1, to indicate that a default port is to be used.
133 * The following are valid examples:
141 * \param url The URL string to take apart.
142 * \param host To return the copied host part of \a url.
143 * \param hostlen The maximum length of \a host.
144 * \param port To return the port number (if any) of \a url.
146 * \return Pointer to \a host, or NULL if failed.
147 * If NULL is returned, \a host and \a portnum are undefined. If no
148 * port number was present in \a url, \a portnum is set to -1.
150 * \sa RFC 3986, 3.2.2/3.2.3
152 char *parse_url(const char *url,
153 char *host, ssize_t hostlen,
157 char *c = host, *end = c + (hostlen - 1);
161 if (o == NULL || hostlen < 1)
165 for (++o; (*c = *o == ']' ? '\0' : *o); c++, o++)
169 if (*o++ != ']' || (*o != '\0' && *o != ':'))
172 for (; (*c = *o == ':'? '\0' : *o); c++, o++)
178 if (para_atoi32(++o, port) < 0 ||
179 *port < 0 || *port > 0xffff)
182 if (host_string_ok(host))
190 * Determine the socket type for a given layer-4 protocol.
192 * \param l4type The symbolic name of the transport-layer protocol.
194 * \sa ip(7), socket(2)
196 static inline int sock_type(const unsigned l4type)
199 case IPPROTO_UDP: return SOCK_DGRAM;
200 case IPPROTO_TCP: return SOCK_STREAM;
201 case IPPROTO_DCCP: return SOCK_DCCP;
203 return -1; /* not supported here */
207 * Pretty-print transport-layer name.
209 static const char *layer4_name(const unsigned l4type)
212 case IPPROTO_UDP: return "UDP";
213 case IPPROTO_TCP: return "TCP";
214 case IPPROTO_DCCP: return "DCCP";
216 return "UNKNOWN PROTOCOL";
220 * Resolve IPv4/IPv6 address and create a ready-to-use active or passive socket.
222 * \param l3type The layer-3 type (\p AF_INET, \p AF_INET6, \p AF_UNSPEC).
223 * \param l4type The layer-4 type (\p IPPROTO_xxx).
224 * \param passive Whether this is a passive (1) or active (0) socket.
225 * \param host Remote or local hostname or IPv/6 address string.
226 * \param port_number Decimal port number.
228 * This creates a ready-made IPv4/v6 socket structure after looking up the
229 * necessary parameters. The interpretation of \a host depends on the value of
231 * - on a passive socket host is interpreted as an interface IPv4/6 address
232 * (can be left NULL);
233 * - on an active socket, \a host is the peer DNS name or IPv4/6 address
235 * - \a port_number is in either case the numeric port number (not service
238 * Furthermore, bind(2) is called on passive sockets, and connect(2) on active
239 * sockets. The algorithm tries all possible address combinations until it
242 * \return This function returns 1 on success and \a -E_ADDRESS_LOOKUP when no
243 * matching connection could be set up (with details in the error log).
245 * \sa ipv6(7), getaddrinfo(3), bind(2), connect(2).
247 int makesock(unsigned l3type, unsigned l4type, int passive,
248 const char *host, unsigned short port_number)
250 struct addrinfo *local = NULL, *src,
251 *remote = NULL, *dst, hints;
252 int rc, on = 1, sockfd = -1,
253 socktype = sock_type(l4type);
254 char port[6]; /* port number has at most 5 digits */
256 sprintf(port, "%u", port_number);
257 /* Set up address hint structure */
258 memset(&hints, 0, sizeof(hints));
259 hints.ai_family = l3type;
260 hints.ai_socktype = socktype;
262 * getaddrinfo does not support SOCK_DCCP, so for the sake of lookup
263 * (and only then) pretend to be UDP.
265 if (l4type == IPPROTO_DCCP)
266 hints.ai_socktype = SOCK_DGRAM;
268 /* only use addresses available on the host */
269 hints.ai_flags = AI_ADDRCONFIG;
270 if (l3type == AF_INET6)
271 /* use v4-mapped-v6 if no v6 addresses found */
272 hints.ai_flags |= AI_V4MAPPED | AI_ALL;
274 if (passive && host == NULL)
275 hints.ai_flags |= AI_PASSIVE;
277 /* Obtain local/remote address information */
278 if ((rc = getaddrinfo(host, port, &hints, passive ? &local : &remote))) {
279 PARA_ERROR_LOG("can not resolve %s address %s#%s: %s.\n",
281 host? host : (passive? "[loopback]" : "[localhost]"),
282 port, gai_strerror(rc));
283 return -E_ADDRESS_LOOKUP;
286 /* Iterate over all src/dst combination, exhausting dst first */
287 for (src = local, dst = remote; src != NULL || dst != NULL; /* no op */ ) {
288 if (src && dst && src->ai_family == AF_INET
289 && dst->ai_family == AF_INET6)
290 goto get_next_dst; /* v4 -> v6 is not possible */
292 sockfd = socket(src ? src->ai_family : dst->ai_family,
298 * Set those options that need to be set before establishing
299 * the connection. Reuse the address on passive (listening)
300 * sockets to avoid failure on restart.
302 if (passive && setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
303 &on, sizeof(on)) == -1) {
304 PARA_ERROR_LOG("can not set SO_REUSEADDR: %s\n",
306 return -ERRNO_TO_PARA_ERROR(errno);
310 if (bind(sockfd, src->ai_addr, src->ai_addrlen) < 0) {
314 if (!dst) /* bind-only completed successfully */
318 if (dst && connect(sockfd, dst->ai_addr, dst->ai_addrlen) == 0)
319 break; /* connection completed successfully */
322 if (dst && (dst = dst->ai_next))
325 if (src && (src = src->ai_next)) /* restart inner loop */
331 freeaddrinfo(remote);
333 if (src == NULL && dst == NULL) {
334 PARA_ERROR_LOG("can not create %s socket %s#%s.\n",
335 layer4_name(l4type), host? host : (passive?
336 "[loopback]" : "[localhost]"), port);
337 return -ERRNO_TO_PARA_ERROR(errno);
343 * Create a passive / listening socket.
345 * \param l3type The network-layer type (\p AF_xxx).
346 * \param l4type The transport-layer type (\p IPPROTO_xxx).
347 * \param port The decimal port number to listen on.
349 * \return Positive integer (socket descriptor) on success, negative value
352 * \sa makesock(), ip(7), ipv6(7), bind(2), listen(2).
354 int para_listen(unsigned l3type, unsigned l4type, unsigned short port)
356 int ret, fd = makesock(l3type, l4type, 1, NULL, port);
359 ret = listen(fd, BACKLOG);
362 return -ERRNO_TO_PARA_ERROR(errno);
364 PARA_INFO_LOG("listening on %s port %u, fd %d\n",
365 layer4_name(l4type), port, fd);
371 * Print numeric host and port number (beware - uses static char).
373 * \param sa The IPv4/IPv6 socket address to use.
374 * \param len The length of \p sa.
376 * \sa getnameinfo(3).
378 static char *host_and_port(struct sockaddr *sa, socklen_t len)
380 static char output[NI_MAXHOST + NI_MAXSERV + 2];
381 char hbuf[NI_MAXHOST], sbuf[NI_MAXSERV];
384 ret = getnameinfo(sa, len, hbuf, sizeof(hbuf), sbuf, sizeof(sbuf),
385 NI_NUMERICHOST | NI_NUMERICSERV);
387 PARA_WARNING_LOG("hostname lookup error (%s).\n",
389 sprintf(output, "(unknown)");
391 sprintf(output, "%s#%s", hbuf, sbuf);
396 * Look up the local or remote side of a connected socket structure.
398 * \param fd The socket descriptor of the connected socket.
399 * \param getname Either \p getsockname() for local, or \p getpeername() for
402 * \return A static character string identifying hostname and port of the
405 * \sa getsockname(2), getpeername(2).
407 static char *__get_sock_name(int fd, int (*getname)(int, struct sockaddr*,
410 struct sockaddr_storage ss;
411 socklen_t sslen = sizeof(ss);
413 if (getname(fd, (struct sockaddr *)&ss, &sslen) < 0) {
414 static char *dont_know = "(don't know)";
415 PARA_ERROR_LOG("can not determine address from fd %d: %s\n",
416 fd, strerror(errno));
419 return host_and_port((struct sockaddr *)&ss, sslen);
423 * Look up the local side of a connected socket structure.
425 * \param sockfd The file descriptor of the socket.
427 * \return A pointer to a static buffer containing hostname an port. This
428 * buffer must not be freed by the caller.
432 char *local_name(int sockfd)
434 return __get_sock_name(sockfd, getsockname);
438 * Look up the remote side of a connected socket structure.
440 * \param sockfd The file descriptor of the socket.
442 * \return Analogous to the return value of \ref local_name() but for the
447 char *remote_name(int sockfd)
449 return __get_sock_name(sockfd, getpeername);
453 * Extract IPv4 or IPv6-mapped-IPv4 address from sockaddr_storage.
454 * \param ss Container of IPv4/6 address
455 * \return Extracted IPv4 address (different from 0) or 0 if unsuccessful.
459 struct in_addr extract_v4_addr(const struct sockaddr_storage *ss)
461 struct in_addr ia = {.s_addr = 0};
463 if (ss->ss_family == AF_INET)
464 ia.s_addr = ((struct sockaddr_in *)ss)->sin_addr.s_addr;
465 if (ss->ss_family == AF_INET6) {
466 const struct in6_addr v6_addr = ((struct sockaddr_in6 *)ss)->sin6_addr;
468 if (IN6_IS_ADDR_V4MAPPED(&v6_addr))
469 memcpy(&ia.s_addr, &(v6_addr.s6_addr[12]), 4);
475 * Send a binary buffer.
477 * \param fd The file descriptor.
478 * \param buf The buffer to be sent.
479 * \param len The length of \a buf.
481 * Send out the buffer and try to resend the remaining part in case of short
486 int send_bin_buffer(int fd, const char *buf, size_t len)
489 PARA_CRIT_LOG("len == 0\n");
490 return write_all(fd, buf, &len);
494 * Send a \p NULL-terminated buffer.
496 * \param fd The file descriptor.
497 * \param buf The null-terminated buffer to be send.
499 * This is equivalent to send_bin_buffer(fd, buf, strlen(buf)).
503 int send_buffer(int fd, const char *buf)
505 return send_bin_buffer(fd, buf, strlen(buf));
509 * Send a buffer given by a format string.
511 * \param fd The file descriptor.
512 * \param fmt A format string.
516 __printf_2_3 int send_va_buffer(int fd, const char *fmt, ...)
521 PARA_VSPRINTF(fmt, msg);
522 ret = send_buffer(fd, msg);
528 * Receive data from a file descriptor.
530 * \param fd The file descriptor.
531 * \param buf The buffer to write the data to.
532 * \param size The size of \a buf.
534 * Receive at most \a size bytes from file descriptor \a fd.
536 * \return The number of bytes received on success, negative on errors, zero if
537 * the peer has performed an orderly shutdown.
541 __must_check int recv_bin_buffer(int fd, char *buf, size_t size)
545 n = recv(fd, buf, size, 0);
547 return -ERRNO_TO_PARA_ERROR(errno);
552 * Receive and write terminating NULL byte.
554 * \param fd The file descriptor.
555 * \param buf The buffer to write the data to.
556 * \param size The size of \a buf.
558 * Read at most \a size - 1 bytes from file descriptor \a fd and
559 * write a NULL byte at the end of the received data.
561 * \return The return value of the underlying call to \a recv_bin_buffer().
563 * \sa recv_bin_buffer()
565 int recv_buffer(int fd, char *buf, size_t size)
570 n = recv_bin_buffer(fd, buf, size - 1);
579 * Wrapper around the accept system call.
581 * \param fd The listening socket.
582 * \param addr Structure which is filled in with the address of the peer socket.
583 * \param size Should contain the size of the structure pointed to by \a addr.
585 * Accept incoming connections on \a addr. Retry if interrupted.
587 * \return The new file descriptor on success, negative on errors.
591 int para_accept(int fd, void *addr, socklen_t size)
596 new_fd = accept(fd, (struct sockaddr *) addr, &size);
597 while (new_fd < 0 && errno == EINTR);
598 return new_fd < 0? -ERRNO_TO_PARA_ERROR(errno) : new_fd;
602 * Prepare a structure for \p AF_UNIX socket addresses.
604 * \param u Pointer to the struct to be prepared.
605 * \param name The socket pathname.
607 * This just copies \a name to the sun_path component of \a u.
609 * \return Positive on success, \p -E_NAME_TOO_LONG if \a name is longer
610 * than \p UNIX_PATH_MAX.
612 static int init_unix_addr(struct sockaddr_un *u, const char *name)
614 if (strlen(name) >= UNIX_PATH_MAX)
615 return -E_NAME_TOO_LONG;
616 memset(u->sun_path, 0, UNIX_PATH_MAX);
617 u->sun_family = PF_UNIX;
618 strcpy(u->sun_path, name);
623 * Prepare, create, and bind a socket for local communication.
625 * \param name The socket pathname.
626 * \param unix_addr Pointer to the \p AF_UNIX socket structure.
627 * \param mode The desired mode of the socket.
629 * This function creates a local socket for sequenced, reliable,
630 * two-way, connection-based byte streams.
632 * \return The file descriptor, on success, negative on errors.
638 int create_local_socket(const char *name, struct sockaddr_un *unix_addr,
643 ret = init_unix_addr(unix_addr, name);
646 ret = socket(PF_UNIX, SOCK_STREAM, 0);
648 return -ERRNO_TO_PARA_ERROR(errno);
650 ret = bind(fd, (struct sockaddr *) unix_addr, UNIX_PATH_MAX);
652 ret = -ERRNO_TO_PARA_ERROR(errno);
656 if (chmod(name, mode) < 0)
665 * Prepare, create, and connect to a Unix domain socket for local communication.
667 * \param name The socket pathname.
669 * This function creates a local socket for sequenced, reliable, two-way,
670 * connection-based byte streams.
672 * \return The file descriptor, on success, negative on errors.
674 * \sa create_local_socket(), unix(7), connect(2).
676 int create_remote_socket(const char *name)
678 struct sockaddr_un unix_addr;
681 ret = init_unix_addr(&unix_addr, name);
684 fd = socket(PF_UNIX, SOCK_STREAM, 0);
686 return -ERRNO_TO_PARA_ERROR(errno);
687 if (connect(fd, (struct sockaddr *)&unix_addr, sizeof(unix_addr)) == -1) {
688 ret = -ERRNO_TO_PARA_ERROR(errno);
698 ssize_t send_cred_buffer(int sock, char *buf)
700 return send_buffer(sock, buf);
702 int recv_cred_buffer(int fd, char *buf, size_t size)
704 return recv_buffer(fd, buf, size) > 0? 1 : -E_RECVMSG;
706 #else /* HAVE_UCRED */
708 * Send \p NULL-terminated buffer and Unix credentials of the current process.
710 * \param sock The socket file descriptor.
711 * \param buf The buffer to be sent.
713 * \return On success, this call returns the number of characters sent. On
714 * error, \p -E_SENDMSG is returned.
716 * \sa sendmsg(2), okir's Black Hats Manual.
718 ssize_t send_cred_buffer(int sock, char *buf)
720 char control[sizeof(struct cmsghdr) + sizeof(struct ucred)];
722 struct cmsghdr *cmsg;
723 static struct iovec iov;
729 iov.iov_len = strlen(buf);
733 /* compose the message */
734 memset(&msg, 0, sizeof(msg));
737 msg.msg_control = control;
738 msg.msg_controllen = sizeof(control);
739 /* attach the ucred struct */
740 cmsg = CMSG_FIRSTHDR(&msg);
741 cmsg->cmsg_level = SOL_SOCKET;
742 cmsg->cmsg_type = SCM_CREDENTIALS;
743 cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred));
744 *(struct ucred *)CMSG_DATA(cmsg) = c;
745 msg.msg_controllen = cmsg->cmsg_len;
746 ret = sendmsg(sock, &msg, 0);
752 static void dispose_fds(int *fds, unsigned num)
756 for (i = 0; i < num; i++)
761 * Receive a buffer and the Unix credentials of the sending process.
763 * \param fd the socket file descriptor.
764 * \param buf the buffer to store the message.
765 * \param size the size of \a buffer.
767 * \return negative on errors, the user id on success.
769 * \sa recvmsg(2), okir's Black Hats Manual.
771 int recv_cred_buffer(int fd, char *buf, size_t size)
775 struct cmsghdr *cmsg;
781 setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &yes, sizeof(int));
782 memset(&msg, 0, sizeof(msg));
783 memset(buf, 0, size);
788 msg.msg_control = control;
789 msg.msg_controllen = sizeof(control);
790 if (recvmsg(fd, &msg, 0) < 0)
792 result = -E_SCM_CREDENTIALS;
793 cmsg = CMSG_FIRSTHDR(&msg);
795 if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type
796 == SCM_CREDENTIALS) {
797 memcpy(&cred, CMSG_DATA(cmsg), sizeof(struct ucred));
800 if (cmsg->cmsg_level == SOL_SOCKET
801 && cmsg->cmsg_type == SCM_RIGHTS) {
802 dispose_fds((int *) CMSG_DATA(cmsg),
803 (cmsg->cmsg_len - CMSG_LEN(0))
806 cmsg = CMSG_NXTHDR(&msg, cmsg);
810 #endif /* HAVE_UCRED */
813 * Receive a buffer and check for a pattern.
815 * \param fd The file descriptor to receive from.
816 * \param pattern The expected pattern.
817 * \param bufsize The size of the internal buffer.
819 * \return Positive if \a pattern was received, negative otherwise.
821 * This function tries to receive at most \a bufsize bytes from file descriptor
822 * \a fd. If at least \p strlen(\a pattern) bytes were received, the beginning
823 * of the received buffer is compared with \a pattern, ignoring case.
825 * \sa recv_buffer(), \sa strncasecmp(3).
827 int recv_pattern(int fd, const char *pattern, size_t bufsize)
829 size_t len = strlen(pattern);
830 char *buf = para_malloc(bufsize + 1);
831 int ret = -E_RECV_PATTERN, n = recv_buffer(fd, buf, bufsize + 1);
835 if (strncasecmp(buf, pattern, len))
840 PARA_NOTICE_LOG("n = %d, did not receive pattern '%s'\n", n,
843 PARA_NOTICE_LOG("recvd: %s\n", buf);