2 * Copyright (C) 2005-2013 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.
15 #include <netinet/in.h>
16 #include <arpa/inet.h>
18 #include <sys/types.h>
19 #include <sys/socket.h>
22 /* At least NetBSD needs these. */
30 #define AI_ADDRCONFIG 0
43 * Parse and validate IPv4 address/netmask string.
45 * \param cidr Address in CIDR notation
46 * \param addr Copy of the IPv4 address part of \a cidr
47 * \param addrlen Size of \a addr in bytes
48 * \param netmask Value of the netmask part in \a cidr or the
49 * default of 32 if not specified.
51 * \return Pointer to \a addr if succesful, NULL on error.
54 char *parse_cidr(const char *cidr,
55 char *addr, ssize_t addrlen,
59 char *c = addr, *end = c + (addrlen - 1);
63 if (cidr == NULL || addrlen < 1)
66 for (o = cidr; (*c = *o == '/'? '\0' : *o); c++, o++)
71 if (para_atoi32(++o, netmask) < 0 ||
72 *netmask < 0 || *netmask > 0x20)
75 if (is_valid_ipv4_address(addr))
84 * Match string as a candidate IPv4 address.
86 * \param address The string to match.
87 * \return True if \a address has "dot-quad" format.
89 static bool is_v4_dot_quad(const char *address)
94 assert(para_regcomp(&r, "^([0-9]+\\.){3}[0-9]+$",
95 REG_EXTENDED | REG_NOSUB) >= 0);
96 result = regexec(&r, address, 0, NULL, 0) == 0;
102 * Perform basic syntax checking on the host-part of an URL:
104 * - Since ':' is invalid in IPv4 addresses and DNS names, the
105 * presence of ':' causes interpretation as IPv6 address;
106 * - next the first-match-wins algorithm from RFC 3986 is applied;
107 * - else the string is considered as DNS name, to be resolved later.
109 * \param host The host string to check.
110 * \return True if \a host passes the syntax checks.
112 * \sa RFC 3986, 3.2.2; RFC 1123, 2.1; RFC 1034, 3.5
114 static bool host_string_ok(const char *host)
116 if (host == NULL || *host == '\0')
118 if (strchr(host, ':') != NULL)
119 return is_valid_ipv6_address(host);
120 if (is_v4_dot_quad(host))
121 return is_valid_ipv4_address(host);
126 * Parse and validate URL string.
128 * The URL syntax is loosely based on RFC 3986, supporting one of
129 * - "["host"]"[:port] for native IPv6 addresses and
130 * - host[:port] for IPv4 hostnames and DNS names.
132 * Native IPv6 addresses must be enclosed in square brackets, since
133 * otherwise there is an ambiguity with the port separator `:'.
134 * The 'port' part is always considered to be a number; if absent,
135 * it is set to -1, to indicate that a default port is to be used.
137 * The following are valid examples:
145 * \param url The URL string to take apart.
146 * \param host To return the copied host part of \a url.
147 * \param hostlen The maximum length of \a host.
148 * \param port To return the port number (if any) of \a url.
150 * \return Pointer to \a host, or \p NULL if failed. If \p NULL is returned,
151 * \a host and \a port are undefined. If no port number was present in \a url,
152 * \a port is set to -1.
154 * \sa RFC 3986, 3.2.2/3.2.3
156 char *parse_url(const char *url,
157 char *host, ssize_t hostlen,
161 char *c = host, *end = c + (hostlen - 1);
165 if (o == NULL || hostlen < 1)
169 for (++o; (*c = *o == ']' ? '\0' : *o); c++, o++)
173 if (*o++ != ']' || (*o != '\0' && *o != ':'))
176 for (; (*c = *o == ':'? '\0' : *o); c++, o++) {
177 if (c == end && o[1])
183 if (para_atoi32(++o, port) < 0 ||
184 *port < 0 || *port > 0xffff)
186 if (host_string_ok(host))
194 * Stringify port number, resolve into service name where defined.
195 * \param port 2-byte port number, in host-byte-order.
196 * \param transport Transport protocol name (e.g. "udp", "tcp"), or NULL.
197 * \return Pointer to static result buffer.
199 * \sa getservent(3), services(5), nsswitch.conf(5)
201 const char *stringify_port(int port, const char *transport)
203 static char service[NI_MAXSERV];
205 if (port < 0 || port > 0xFFFF) {
206 snprintf(service, sizeof(service), "undefined (%d)", port);
208 struct servent *se = getservbyport(htons(port), transport);
211 snprintf(service, sizeof(service), "%u", port);
213 snprintf(service, sizeof(service), "%s", se->s_name);
219 * Determine the socket type for a given layer-4 protocol.
221 * \param l4type The symbolic name of the transport-layer protocol.
223 * \sa ip(7), socket(2)
225 static inline int sock_type(const unsigned l4type)
228 case IPPROTO_UDP: return SOCK_DGRAM;
229 case IPPROTO_TCP: return SOCK_STREAM;
230 case IPPROTO_DCCP: return SOCK_DCCP;
232 return -1; /* not supported here */
236 * Pretty-print transport-layer name.
238 static const char *layer4_name(const unsigned l4type)
241 case IPPROTO_UDP: return "UDP";
242 case IPPROTO_TCP: return "TCP";
243 case IPPROTO_DCCP: return "DCCP";
245 return "UNKNOWN PROTOCOL";
249 * Flowopts: Transport-layer independent encapsulation of socket options.
251 * These collect individual socket options into a queue, which is disposed of
252 * directly after makesock(). The 'pre_conn_opt' structure is for internal use
253 * only and should not be visible elsewhere.
255 * \sa setsockopt(2), makesock()
257 struct pre_conn_opt {
258 int sock_level; /**< Second argument to setsockopt() */
259 int sock_option; /**< Third argument to setsockopt() */
260 char *opt_name; /**< Stringified \a sock_option */
261 void *opt_val; /**< Fourth argument to setsockopt() */
262 socklen_t opt_len; /**< Fifth argument to setsockopt() */
264 struct list_head node; /**< FIFO, as sockopt order matters. */
267 /** FIFO list of pre-connection socket options to be set */
269 struct list_head sockopts;
273 * Allocate and initialize a flowopt queue.
275 * \return A new structure to be passed to \ref flowopt_add(). It is
276 * automatically deallocated in \ref makesock().
278 struct flowopts *flowopt_new(void)
280 struct flowopts *new = para_malloc(sizeof(*new));
282 INIT_LIST_HEAD(&new->sockopts);
287 * Append new socket option to flowopt queue.
289 * \param fo The flowopt queue to append to.
290 * \param lev Level at which \a opt resides.
291 * \param opt New option to add.
292 * \param name Stringified name of \a opt.
293 * \param val The value to set \a opt to.
294 * \param len Length of \a val.
298 void flowopt_add(struct flowopts *fo, int lev, int opt,
299 const char *name, const void *val, int len)
301 struct pre_conn_opt *new = para_malloc(sizeof(*new));
303 new->sock_option = opt;
304 new->sock_level = lev;
305 new->opt_name = para_strdup(name);
311 new->opt_val = para_malloc(len);
313 memcpy(new->opt_val, val, len);
316 list_add_tail(&new->node, &fo->sockopts);
319 /** Set the entire bunch of pre-connection options at once. */
320 static void flowopt_setopts(int sockfd, struct flowopts *fo)
322 struct pre_conn_opt *pc;
327 list_for_each_entry(pc, &fo->sockopts, node)
328 if (setsockopt(sockfd, pc->sock_level, pc->sock_option,
329 pc->opt_val, pc->opt_len) < 0) {
330 PARA_EMERG_LOG("Can not set %s socket option: %s",
331 pc->opt_name, strerror(errno));
336 static void flowopt_cleanup(struct flowopts *fo)
338 struct pre_conn_opt *cur, *next;
343 list_for_each_entry_safe(cur, next, &fo->sockopts, node) {
352 * Resolve an IPv4/IPv6 address.
354 * \param l4type The layer-4 type (\p IPPROTO_xxx).
355 * \param passive Whether \p AI_PASSIVE should be included as hint.
356 * \param host Remote or local hostname or IPv/6 address string.
357 * \param port_number Used to set the port in each returned address structure.
358 * \param result addrinfo structures are returned here.
360 * The interpretation of \a host depends on the value of \a passive. On a
361 * passive socket host is interpreted as an interface IPv4/6 address (can be
362 * left NULL). On an active socket, \a host is the peer DNS name or IPv4/6
363 * address to connect to.
367 * \sa getaddrinfo(3).
369 static int lookup_address(unsigned l4type, bool passive, const char *host,
370 int port_number, struct addrinfo **result)
373 char port[6]; /* port number has at most 5 digits */
374 struct addrinfo *addr = NULL, hints;
377 sprintf(port, "%u", port_number & 0xffff);
378 /* Set up address hint structure */
379 memset(&hints, 0, sizeof(hints));
380 hints.ai_family = AF_UNSPEC;
381 hints.ai_socktype = sock_type(l4type);
383 * getaddrinfo does not support SOCK_DCCP, so for the sake of lookup
384 * (and only then) pretend to be UDP.
386 if (l4type == IPPROTO_DCCP)
387 hints.ai_socktype = SOCK_DGRAM;
388 /* only use addresses available on the host */
389 hints.ai_flags = AI_ADDRCONFIG;
390 if (passive && host == NULL)
391 hints.ai_flags |= AI_PASSIVE;
392 /* Obtain local/remote address information */
393 ret = getaddrinfo(host, port, &hints, &addr);
395 PARA_ERROR_LOG("can not resolve %s address %s#%s: %s\n",
397 host? host : (passive? "[loopback]" : "[localhost]"),
398 port, gai_strerror(ret));
399 return -E_ADDRESS_LOOKUP;
406 * Create an active or passive socket.
408 * \param l4type \p IPPROTO_TCP, \p IPPROTO_UDP, or \p IPPROTO_DCCP.
409 * \param passive Whether to call bind(2) or connect(2).
410 * \param ai Address information as obtained from \ref lookup_address().
411 * \param fo Socket options to be set before making the connection.
413 * bind(2) is called on passive sockets, and connect(2) on active sockets. The
414 * algorithm tries all possible address combinations until it succeeds. If \a
415 * fo is supplied, options are set and cleanup is performed.
417 * \return File descriptor on success, \p E_MAKESOCK on errors.
419 * \sa \ref lookup_address(), \ref makesock(), ip(7), ipv6(7), bind(2),
422 static int makesock_addrinfo(unsigned l4type, bool passive, struct addrinfo *ai,
425 struct addrinfo *local, *remote, *src = NULL, *dst = NULL;
426 int ret = -E_MAKESOCK, on = 1, sockfd = -1;
436 /* Iterate over all src/dst combination, exhausting dst first */
437 for (src = local, dst = remote; src != NULL || dst != NULL; /* no op */ ) {
438 if (src && dst && src->ai_family == AF_INET
439 && dst->ai_family == AF_INET6)
440 goto get_next_dst; /* v4 -> v6 is not possible */
442 ret = socket(src ? src->ai_family : dst->ai_family,
443 sock_type(l4type), l4type);
448 * Reuse the address on passive sockets to avoid failure on
449 * restart (protocols using listen()) and when creating
450 * multiple listener instances (UDP multicast).
452 if (passive && setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
453 &on, sizeof(on)) == -1) {
454 ret = -ERRNO_TO_PARA_ERROR(errno);
456 PARA_ERROR_LOG("can not set SO_REUSEADDR: %s\n",
457 para_strerror(-ret));
460 flowopt_setopts(sockfd, fo);
463 if (bind(sockfd, src->ai_addr, src->ai_addrlen) < 0) {
467 if (!dst) /* bind-only completed successfully */
471 if (dst && connect(sockfd, dst->ai_addr, dst->ai_addrlen) == 0)
472 break; /* connection completed successfully */
475 if (dst && (dst = dst->ai_next))
478 if (src && (src = src->ai_next)) /* restart inner loop */
481 if (src == NULL && dst == NULL)
482 return ret < 0? ret : -E_MAKESOCK;
487 * Resolve IPv4/IPv6 address and create a ready-to-use active or passive socket.
489 * \param l4type The layer-4 type (\p IPPROTO_xxx).
490 * \param passive Whether this is a passive or active socket.
491 * \param host Passed to \ref lookup_address().
492 * \param port_number Passed to \ref lookup_address().
493 * \param fo Passed to \ref makesock_addrinfo().
495 * This creates a ready-made IPv4/v6 socket structure after looking up the
496 * necessary parameters. The function first calls \ref lookup_address() and
497 * passes the address information to makesock_addrinfo() to create and
498 * initialize the socket.
500 * \return The newly created file descriptor on success, a negative error code
503 * \sa \ref lookup_address(), \ref makesock_addrinfo().
505 int makesock(unsigned l4type, bool passive, const char *host, uint16_t port_number,
509 int ret = lookup_address(l4type, passive, host, port_number, &ai);
512 ret = makesock_addrinfo(l4type, passive, ai, fo);
517 PARA_ERROR_LOG("can not create %s socket %s#%d.\n",
518 layer4_name(l4type), host? host : (passive?
519 "[loopback]" : "[localhost]"), port_number);
525 * Create a passive / listening socket.
527 * \param l4type The transport-layer type (\p IPPROTO_xxx).
528 * \param port The decimal port number to listen on.
529 * \param fo Flowopts (if any) to set before starting to listen.
531 * \return Positive integer (socket descriptor) on success, negative value
534 * \sa makesock(), ip(7), ipv6(7), bind(2), listen(2).
536 int para_listen(unsigned l4type, uint16_t port, struct flowopts *fo)
538 int ret, fd = makesock(l4type, 1, NULL, port, fo);
541 ret = listen(fd, BACKLOG);
545 return -ERRNO_TO_PARA_ERROR(ret);
547 PARA_INFO_LOG("listening on %s port %u, fd %d\n",
548 layer4_name(l4type), port, fd);
554 * Determine IPv4/v6 socket address length.
555 * \param sa Container of IPv4 or IPv6 address.
556 * \return Address-family dependent address length.
558 static socklen_t salen(const struct sockaddr *sa)
560 assert(sa->sa_family == AF_INET || sa->sa_family == AF_INET6);
562 return sa->sa_family == AF_INET6
563 ? sizeof(struct sockaddr_in6)
564 : sizeof(struct sockaddr_in);
567 /** True if @ss holds a v6-mapped-v4 address (RFC 4291, 2.5.5.2) */
568 static bool SS_IS_ADDR_V4MAPPED(const struct sockaddr_storage *ss)
570 const struct sockaddr_in6 *ia6 = (const struct sockaddr_in6 *)ss;
572 return ss->ss_family == AF_INET6 && IN6_IS_ADDR_V4MAPPED(&ia6->sin6_addr);
576 * Process IPv4/v6 address, turn v6-mapped-v4 address into normal IPv4 address.
577 * \param ss Container of IPv4/6 address.
578 * \return Pointer to normalized address (may be static storage).
582 static const struct sockaddr *
583 normalize_ip_address(const struct sockaddr_storage *ss)
585 assert(ss->ss_family == AF_INET || ss->ss_family == AF_INET6);
587 if (SS_IS_ADDR_V4MAPPED(ss)) {
588 const struct sockaddr_in6 *ia6 = (const struct sockaddr_in6 *)ss;
589 static struct sockaddr_in ia;
591 ia.sin_family = AF_INET;
592 ia.sin_port = ia6->sin6_port;
593 memcpy(&ia.sin_addr.s_addr, &(ia6->sin6_addr.s6_addr[12]), 4);
594 return (const struct sockaddr *)&ia;
596 return (const struct sockaddr *)ss;
600 * Generic/fallback MTU values
602 * These are taken from RFC 1122, RFC 2460, and RFC 5405.
603 * - RFC 1122, 3.3.3 defines EMTU_S ("Effective MTU for sending") and recommends
604 * to use an EMTU_S size of of 576 bytes if the IPv4 path MTU is unknown;
605 * - RFC 2460, 5. requires a minimum IPv6 MTU of 1280 bytes;
606 * - RFC 5405, 3.2 recommends that if path MTU discovery is not done,
607 * UDP senders should use the respective minimum values of EMTU_S.
609 static inline int generic_mtu(const int af_type)
611 return af_type == AF_INET6 ? 1280 : 576;
614 /** Crude approximation of IP header overhead - neglecting options. */
615 static inline int estimated_header_overhead(const int af_type)
617 return af_type == AF_INET6 ? 40 : 20;
621 * Get the maximum transport-layer message size (MMS_S).
623 * \param sockfd The socket file descriptor.
625 * The socket must be connected. See RFC 1122, 3.3.3. If the protocol familiy
626 * could not be determined, \p AF_INET is assumed.
628 * \return The maximum message size of the address family type.
630 int generic_max_transport_msg_size(int sockfd)
632 struct sockaddr_storage ss;
633 socklen_t sslen = sizeof(ss);
634 int af_type = AF_INET;
636 if (getpeername(sockfd, (struct sockaddr *)&ss, &sslen) < 0) {
637 PARA_ERROR_LOG("can not determine remote address type: %s\n",
639 } else if (!SS_IS_ADDR_V4MAPPED(&ss)) {
640 af_type = ss.ss_family;
642 return generic_mtu(af_type) - estimated_header_overhead(af_type);
646 * Look up the local or remote side of a connected socket structure.
648 * \param fd The socket descriptor of the connected socket.
649 * \param getname Either \p getsockname() for local, or \p getpeername() for
652 * \return A static character string identifying hostname and port of the
653 * chosen side in numeric host:port format.
655 * \sa getsockname(2), getpeername(2), parse_url(), getnameinfo(3),
656 * services(5), nsswitch.conf(5).
658 static char *__get_sock_name(int fd, typeof(getsockname) getname)
660 struct sockaddr_storage ss;
661 const struct sockaddr *sa;
662 socklen_t sslen = sizeof(ss);
663 char hbuf[NI_MAXHOST], sbuf[NI_MAXSERV];
664 static char output[sizeof(hbuf) + sizeof(sbuf) + 4];
667 if (getname(fd, (struct sockaddr *)&ss, &sslen) < 0) {
668 PARA_ERROR_LOG("can not determine address from fd %d: %s\n",
669 fd, strerror(errno));
670 snprintf(output, sizeof(output), "(unknown)");
673 sa = normalize_ip_address(&ss);
674 ret = getnameinfo(sa, salen(sa), hbuf, sizeof(hbuf), sbuf,
675 sizeof(sbuf), NI_NUMERICHOST | NI_NUMERICSERV);
677 PARA_WARNING_LOG("hostname lookup error (%s).\n",
679 snprintf(output, sizeof(output), "(lookup error)");
680 } else if (sa->sa_family == AF_INET6)
681 snprintf(output, sizeof(output), "[%s]:%s", hbuf, sbuf);
683 snprintf(output, sizeof(output), "%s:%s", hbuf, sbuf);
688 * Look up the local side of a connected socket structure.
690 * \param sockfd The file descriptor of the socket.
692 * \return A pointer to a static buffer containing hostname an port. This
693 * buffer must not be freed by the caller.
697 char *local_name(int sockfd)
699 return __get_sock_name(sockfd, getsockname);
703 * Look up the remote side of a connected socket structure.
705 * \param sockfd The file descriptor of the socket.
707 * \return Analogous to the return value of \ref local_name() but for the
712 char *remote_name(int sockfd)
714 return __get_sock_name(sockfd, getpeername);
718 * Extract IPv4 or IPv6-mapped-IPv4 address from sockaddr_storage.
720 * \param ss Container of IPv4/6 address.
721 * \param ia Extracted IPv4 address (different from 0) or 0 if unsuccessful.
725 void extract_v4_addr(const struct sockaddr_storage *ss, struct in_addr *ia)
727 const struct sockaddr *sa = normalize_ip_address(ss);
729 memset(ia, 0, sizeof(*ia));
730 if (sa->sa_family == AF_INET)
731 *ia = ((struct sockaddr_in *)sa)->sin_addr;
735 * Receive data from a file descriptor.
737 * \param fd The file descriptor.
738 * \param buf The buffer to write the data to.
739 * \param size The size of \a buf.
741 * Receive at most \a size bytes from file descriptor \a fd.
743 * \return The number of bytes received on success, negative on errors, zero if
744 * the peer has performed an orderly shutdown.
748 __must_check int recv_bin_buffer(int fd, char *buf, size_t size)
752 n = recv(fd, buf, size, 0);
754 return -ERRNO_TO_PARA_ERROR(errno);
759 * Receive and write terminating NULL byte.
761 * \param fd The file descriptor.
762 * \param buf The buffer to write the data to.
763 * \param size The size of \a buf.
765 * Read at most \a size - 1 bytes from file descriptor \a fd and
766 * write a NULL byte at the end of the received data.
768 * \return The return value of the underlying call to \a recv_bin_buffer().
770 * \sa recv_bin_buffer()
772 int recv_buffer(int fd, char *buf, size_t size)
777 n = recv_bin_buffer(fd, buf, size - 1);
786 * Wrapper around the accept system call.
788 * \param fd The listening socket.
789 * \param rfds An optional fd_set pointer.
790 * \param addr Structure which is filled in with the address of the peer socket.
791 * \param size Should contain the size of the structure pointed to by \a addr.
792 * \param new_fd Result pointer.
794 * Accept incoming connections on \a addr, retry if interrupted. If \a rfds is
795 * not \p NULL, return 0 if \a fd is not set in \a rfds without calling accept().
797 * \return Negative on errors, zero if no connections are present to be accepted,
802 int para_accept(int fd, fd_set *rfds, void *addr, socklen_t size, int *new_fd)
806 if (rfds && !FD_ISSET(fd, rfds))
809 ret = accept(fd, (struct sockaddr *) addr, &size);
810 while (ret < 0 && errno == EINTR);
816 if (errno == EAGAIN || errno == EWOULDBLOCK)
818 return -ERRNO_TO_PARA_ERROR(errno);
822 * Probe the list of DCCP CCIDs configured on this host.
823 * \param ccid_array Pointer to return statically allocated array in.
824 * \return Number of elements returned in \a ccid_array or error.
826 * NB: This feature is only available on Linux > 2.6.30; on older kernels
827 * ENOPROTOOPT ("Protocol not available") will be returned.
829 int dccp_available_ccids(uint8_t **ccid_array)
831 static uint8_t ccids[DCCP_MAX_HOST_CCIDS];
832 socklen_t nccids = sizeof(ccids);
835 ret = fd = makesock(IPPROTO_DCCP, 1, NULL, 0, NULL);
839 if (getsockopt(fd, SOL_DCCP, DCCP_SOCKOPT_AVAILABLE_CCIDS,
840 ccids, &nccids) < 0) {
843 PARA_ERROR_LOG("No DCCP_SOCKOPT_AVAILABLE_CCIDS: %s\n",
845 return -ERRNO_TO_PARA_ERROR(ret);
854 * Prepare a structure for \p AF_UNIX socket addresses.
856 * \param u Pointer to the struct to be prepared.
857 * \param name The socket pathname.
859 * This just copies \a name to the sun_path component of \a u.
861 * \return Positive on success, \p -E_NAME_TOO_LONG if \a name is longer
862 * than \p UNIX_PATH_MAX.
864 static int init_unix_addr(struct sockaddr_un *u, const char *name)
866 if (strlen(name) >= UNIX_PATH_MAX)
867 return -E_NAME_TOO_LONG;
868 memset(u->sun_path, 0, UNIX_PATH_MAX);
869 u->sun_family = PF_UNIX;
870 strcpy(u->sun_path, name);
875 * Prepare, create, and bind a socket for local communication.
877 * \param name The socket pathname.
878 * \param unix_addr Pointer to the \p AF_UNIX socket structure.
879 * \param mode The desired mode of the socket.
881 * This function creates a local socket for sequenced, reliable,
882 * two-way, connection-based byte streams.
884 * \return The file descriptor, on success, negative on errors.
890 int create_local_socket(const char *name, struct sockaddr_un *unix_addr,
895 ret = init_unix_addr(unix_addr, name);
898 ret = socket(PF_UNIX, SOCK_STREAM, 0);
900 return -ERRNO_TO_PARA_ERROR(errno);
902 ret = bind(fd, (struct sockaddr *) unix_addr, UNIX_PATH_MAX);
904 ret = -ERRNO_TO_PARA_ERROR(errno);
908 if (chmod(name, mode) < 0)
917 * Prepare, create, and connect to a Unix domain socket for local communication.
919 * \param name The socket pathname.
921 * This function creates a local socket for sequenced, reliable, two-way,
922 * connection-based byte streams.
924 * \return The file descriptor of the connected socket on success, negative on
927 * \sa create_local_socket(), unix(7), connect(2).
929 int connect_local_socket(const char *name)
931 struct sockaddr_un unix_addr;
934 PARA_DEBUG_LOG("connecting to %s\n", name);
935 ret = init_unix_addr(&unix_addr, name);
938 fd = socket(PF_UNIX, SOCK_STREAM, 0);
940 return -ERRNO_TO_PARA_ERROR(errno);
941 if (connect(fd, (struct sockaddr *)&unix_addr, sizeof(unix_addr)) == -1) {
942 ret = -ERRNO_TO_PARA_ERROR(errno);
952 ssize_t send_cred_buffer(int sock, char *buf)
954 return write_buffer(sock, buf);
956 int recv_cred_buffer(int fd, char *buf, size_t size)
958 return recv_buffer(fd, buf, size) > 0? 1 : -E_RECVMSG;
960 #else /* HAVE_UCRED */
962 * Send \p NULL-terminated buffer and Unix credentials of the current process.
964 * \param sock The socket file descriptor.
965 * \param buf The buffer to be sent.
967 * \return On success, this call returns the number of characters sent. On
968 * error, \p -E_SENDMSG is returned.
970 * \sa sendmsg(2), okir's Black Hats Manual.
972 ssize_t send_cred_buffer(int sock, char *buf)
974 char control[sizeof(struct cmsghdr) + sizeof(struct ucred)];
976 struct cmsghdr *cmsg;
977 static struct iovec iov;
983 iov.iov_len = strlen(buf);
987 /* compose the message */
988 memset(&msg, 0, sizeof(msg));
991 msg.msg_control = control;
992 msg.msg_controllen = sizeof(control);
993 /* attach the ucred struct */
994 cmsg = CMSG_FIRSTHDR(&msg);
995 cmsg->cmsg_level = SOL_SOCKET;
996 cmsg->cmsg_type = SCM_CREDENTIALS;
997 cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred));
998 *(struct ucred *)CMSG_DATA(cmsg) = c;
999 msg.msg_controllen = cmsg->cmsg_len;
1000 ret = sendmsg(sock, &msg, 0);
1006 static void dispose_fds(int *fds, unsigned num)
1010 for (i = 0; i < num; i++)
1015 * Receive a buffer and the Unix credentials of the sending process.
1017 * \param fd the socket file descriptor.
1018 * \param buf the buffer to store the message.
1019 * \param size the size of \a buffer.
1021 * \return negative on errors, the user id on success.
1023 * \sa recvmsg(2), okir's Black Hats Manual.
1025 int recv_cred_buffer(int fd, char *buf, size_t size)
1029 struct cmsghdr *cmsg;
1035 setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &yes, sizeof(int));
1036 memset(&msg, 0, sizeof(msg));
1037 memset(buf, 0, size);
1042 msg.msg_control = control;
1043 msg.msg_controllen = sizeof(control);
1044 if (recvmsg(fd, &msg, 0) < 0)
1046 result = -E_SCM_CREDENTIALS;
1047 cmsg = CMSG_FIRSTHDR(&msg);
1049 if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type
1050 == SCM_CREDENTIALS) {
1051 memcpy(&cred, CMSG_DATA(cmsg), sizeof(struct ucred));
1054 if (cmsg->cmsg_level == SOL_SOCKET
1055 && cmsg->cmsg_type == SCM_RIGHTS) {
1056 dispose_fds((int *) CMSG_DATA(cmsg),
1057 (cmsg->cmsg_len - CMSG_LEN(0))
1060 cmsg = CMSG_NXTHDR(&msg, cmsg);
1064 #endif /* HAVE_UCRED */