2 * Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>
4 * Licensed under the GPL v2. For licencing details see COPYING.
7 /** \file net.c Networking-related helper functions. */
11 #include <netinet/in.h>
12 #include <arpa/inet.h>
14 #include <sys/types.h>
15 #include <sys/socket.h>
18 /* At least NetBSD needs these. */
26 #define AI_ADDRCONFIG 0
38 * Parse and validate IPv4 address/netmask string.
40 * \param cidr Address in CIDR notation
41 * \param addr Copy of the IPv4 address part of \a cidr
42 * \param addrlen Size of \a addr in bytes
43 * \param netmask Value of the netmask part in \a cidr or the
44 * default of 32 if not specified.
46 * \return Pointer to \a addr if successful, NULL on error.
49 char *parse_cidr(const char *cidr,
50 char *addr, ssize_t addrlen,
54 char *c = addr, *end = c + (addrlen - 1);
58 if (cidr == NULL || addrlen < 1)
61 for (o = cidr; (*c = *o == '/'? '\0' : *o); c++, o++)
66 if (para_atoi32(++o, netmask) < 0 ||
67 *netmask < 0 || *netmask > 0x20)
70 if (is_valid_ipv4_address(addr))
79 * Match string as a candidate IPv4 address.
81 * \param address The string to match.
82 * \return True if \a address has "dot-quad" format.
84 static bool is_v4_dot_quad(const char *address)
89 assert(para_regcomp(&r, "^([0-9]+\\.){3}[0-9]+$",
90 REG_EXTENDED | REG_NOSUB) >= 0);
91 result = regexec(&r, address, 0, NULL, 0) == 0;
97 * Perform basic syntax checking on the host-part of an URL:
99 * - Since ':' is invalid in IPv4 addresses and DNS names, the
100 * presence of ':' causes interpretation as IPv6 address;
101 * - next the first-match-wins algorithm from RFC 3986 is applied;
102 * - else the string is considered as DNS name, to be resolved later.
104 * \param host The host string to check.
105 * \return True if \a host passes the syntax checks.
107 * \sa RFC 3986, 3.2.2; RFC 1123, 2.1; RFC 1034, 3.5
109 static bool host_string_ok(const char *host)
111 if (host == NULL || *host == '\0')
113 if (strchr(host, ':') != NULL)
114 return is_valid_ipv6_address(host);
115 if (is_v4_dot_quad(host))
116 return is_valid_ipv4_address(host);
121 * Parse and validate URL string.
123 * The URL syntax is loosely based on RFC 3986, supporting one of
124 * - "["host"]"[:port] for native IPv6 addresses and
125 * - host[:port] for IPv4 hostnames and DNS names.
127 * Native IPv6 addresses must be enclosed in square brackets, since
128 * otherwise there is an ambiguity with the port separator `:'.
129 * The 'port' part is always considered to be a number; if absent,
130 * it is set to -1, to indicate that a default port is to be used.
132 * The following are valid examples:
140 * \param url The URL string to take apart.
141 * \param host To return the copied host part of \a url.
142 * \param hostlen The maximum length of \a host.
143 * \param port To return the port number (if any) of \a url.
145 * \return Pointer to \a host, or \p NULL if failed. If \p NULL is returned,
146 * \a host and \a port are undefined. If no port number was present in \a url,
147 * \a port is set to -1.
149 * \sa RFC 3986, 3.2.2/3.2.3
151 char *parse_url(const char *url,
152 char *host, ssize_t hostlen,
156 char *c = host, *end = c + (hostlen - 1);
160 if (o == NULL || hostlen < 1)
164 for (++o; (*c = *o == ']' ? '\0' : *o); c++, o++)
168 if (*o++ != ']' || (*o != '\0' && *o != ':'))
171 for (; (*c = *o == ':'? '\0' : *o); c++, o++) {
172 if (c == end && o[1])
178 if (para_atoi32(++o, port) < 0 || *port < 0 || *port > 0xffff)
180 if (host_string_ok(host))
188 * Stringify port number, resolve into service name where defined.
190 * \param port 2-byte port number, in host-byte-order.
191 * \param transport Transport protocol name (e.g. "udp", "tcp"), or NULL.
192 * \return Pointer to static result buffer.
194 * \sa getservent(3), services(5), nsswitch.conf(5)
196 const char *stringify_port(int port, const char *transport)
198 static char service[NI_MAXSERV];
200 if (port < 0 || port > 0xFFFF) {
201 snprintf(service, sizeof(service), "undefined (%d)", port);
203 struct servent *se = getservbyport(htons(port), transport);
206 snprintf(service, sizeof(service), "%d", port);
208 snprintf(service, sizeof(service), "%s", se->s_name);
214 * Determine the socket type for a given layer-4 protocol.
216 * \param l4type The symbolic name of the transport-layer protocol.
218 * \sa ip(7), socket(2)
220 static inline int sock_type(const unsigned l4type)
223 case IPPROTO_UDP: return SOCK_DGRAM;
224 case IPPROTO_TCP: return SOCK_STREAM;
225 case IPPROTO_DCCP: return SOCK_DCCP;
227 return -1; /* not supported here */
231 * Pretty-print transport-layer name.
233 static const char *layer4_name(const unsigned l4type)
236 case IPPROTO_UDP: return "UDP";
237 case IPPROTO_TCP: return "TCP";
238 case IPPROTO_DCCP: return "DCCP";
240 return "UNKNOWN PROTOCOL";
244 * Flowopts: Transport-layer independent encapsulation of socket options.
246 * These collect individual socket options into a queue, which is disposed of
247 * directly after makesock(). The 'pre_conn_opt' structure is for internal use
248 * only and should not be visible elsewhere.
250 * \sa setsockopt(2), makesock()
252 struct pre_conn_opt {
253 int sock_level; /**< Second argument to setsockopt() */
254 int sock_option; /**< Third argument to setsockopt() */
255 char *opt_name; /**< Stringified \a sock_option */
256 void *opt_val; /**< Fourth argument to setsockopt() */
257 socklen_t opt_len; /**< Fifth argument to setsockopt() */
259 struct list_head node; /**< FIFO, as sockopt order matters. */
262 /** FIFO list of pre-connection socket options to be set */
264 struct list_head sockopts;
268 * Allocate and initialize a flowopt queue.
270 * \return A new structure to be passed to \ref flowopt_add(). It is
271 * automatically deallocated in \ref makesock().
273 struct flowopts *flowopt_new(void)
275 struct flowopts *new = para_malloc(sizeof(*new));
277 INIT_LIST_HEAD(&new->sockopts);
282 * Append new socket option to flowopt queue.
284 * \param fo The flowopt queue to append to.
285 * \param lev Level at which \a opt resides.
286 * \param opt New option to add.
287 * \param name Stringified name of \a opt.
288 * \param val The value to set \a opt to.
289 * \param len Length of \a val.
293 void flowopt_add(struct flowopts *fo, int lev, int opt,
294 const char *name, const void *val, int len)
296 struct pre_conn_opt *new = para_malloc(sizeof(*new));
298 new->sock_option = opt;
299 new->sock_level = lev;
300 new->opt_name = para_strdup(name);
306 new->opt_val = para_malloc(len);
308 memcpy(new->opt_val, val, len);
311 list_add_tail(&new->node, &fo->sockopts);
314 /** Set the entire bunch of pre-connection options at once. */
315 static void flowopt_setopts(int sockfd, struct flowopts *fo)
317 struct pre_conn_opt *pc;
322 list_for_each_entry(pc, &fo->sockopts, node)
323 if (setsockopt(sockfd, pc->sock_level, pc->sock_option,
324 pc->opt_val, pc->opt_len) < 0) {
325 PARA_EMERG_LOG("Can not set %s socket option: %s",
326 pc->opt_name, strerror(errno));
332 * Deallocate all resources of a flowopts structure.
334 * \param fo A pointer as returned from flowopt_new().
336 * It's OK to pass \p NULL here in which case the function does nothing.
338 void flowopt_cleanup(struct flowopts *fo)
340 struct pre_conn_opt *cur, *next;
345 list_for_each_entry_safe(cur, next, &fo->sockopts, node) {
354 * Resolve an IPv4/IPv6 address.
356 * \param l4type The layer-4 type (\p IPPROTO_xxx).
357 * \param passive Whether \p AI_PASSIVE should be included as hint.
358 * \param host Remote or local hostname or IPv/6 address string.
359 * \param port_number Used to set the port in each returned address structure.
360 * \param result addrinfo structures are returned here.
362 * The interpretation of \a host depends on the value of \a passive. On a
363 * passive socket host is interpreted as an interface IPv4/6 address (can be
364 * left NULL). On an active socket, \a host is the peer DNS name or IPv4/6
365 * address to connect to.
369 * \sa getaddrinfo(3).
371 int lookup_address(unsigned l4type, bool passive, const char *host,
372 int port_number, struct addrinfo **result)
375 char port[6]; /* port number has at most 5 digits */
376 struct addrinfo *addr = NULL, hints;
379 sprintf(port, "%d", port_number & 0xffff);
380 /* Set up address hint structure */
381 memset(&hints, 0, sizeof(hints));
382 hints.ai_family = AF_UNSPEC;
383 hints.ai_socktype = sock_type(l4type);
385 * getaddrinfo does not support SOCK_DCCP, so for the sake of lookup
386 * (and only then) pretend to be UDP.
388 if (l4type == IPPROTO_DCCP)
389 hints.ai_socktype = SOCK_DGRAM;
390 /* only use addresses available on the host */
391 hints.ai_flags = AI_ADDRCONFIG;
392 if (passive && host == NULL)
393 hints.ai_flags |= AI_PASSIVE;
394 /* Obtain local/remote address information */
395 ret = getaddrinfo(host, port, &hints, &addr);
397 PARA_ERROR_LOG("can not resolve %s address %s#%s: %s\n",
399 host? host : (passive? "[loopback]" : "[localhost]"),
400 port, gai_strerror(ret));
401 return -E_ADDRESS_LOOKUP;
408 * Create an active or passive socket.
410 * \param l4type \p IPPROTO_TCP, \p IPPROTO_UDP, or \p IPPROTO_DCCP.
411 * \param passive Whether to call bind(2) or connect(2).
412 * \param ai Address information as obtained from \ref lookup_address().
413 * \param fo Socket options to be set before making the connection.
415 * bind(2) is called on passive sockets, and connect(2) on active sockets. The
416 * algorithm tries all possible address combinations until it succeeds. If \a
417 * fo is supplied, options are set but cleanup must be performed in the caller.
419 * \return File descriptor on success, \p E_MAKESOCK on errors.
421 * \sa \ref lookup_address(), \ref makesock(), ip(7), ipv6(7), bind(2),
424 int makesock_addrinfo(unsigned l4type, bool passive, struct addrinfo *ai,
427 int ret = -E_MAKESOCK, on = 1;
429 for (; ai; ai = ai->ai_next) {
431 ret = socket(ai->ai_family, sock_type(l4type), l4type);
435 flowopt_setopts(fd, fo);
437 if (connect(fd, ai->ai_addr, ai->ai_addrlen) == 0)
443 * Reuse the address on passive sockets to avoid failure on
444 * restart (protocols using listen()) and when creating
445 * multiple listener instances (UDP multicast).
447 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on,
452 if (bind(fd, ai->ai_addr, ai->ai_addrlen) < 0) {
462 * Resolve IPv4/IPv6 address and create a ready-to-use active or passive socket.
464 * \param l4type The layer-4 type (\p IPPROTO_xxx).
465 * \param passive Whether this is a passive or active socket.
466 * \param host Passed to \ref lookup_address().
467 * \param port_number Passed to \ref lookup_address().
468 * \param fo Passed to \ref makesock_addrinfo().
470 * This creates a ready-made IPv4/v6 socket structure after looking up the
471 * necessary parameters. The function first calls \ref lookup_address() and
472 * passes the address information to makesock_addrinfo() to create and
473 * initialize the socket.
475 * \return The newly created file descriptor on success, a negative error code
478 * \sa \ref lookup_address(), \ref makesock_addrinfo().
480 int makesock(unsigned l4type, bool passive, const char *host, uint16_t port_number,
484 int ret = lookup_address(l4type, passive, host, port_number, &ai);
487 ret = makesock_addrinfo(l4type, passive, ai, fo);
491 PARA_ERROR_LOG("can not create %s socket %s#%d.\n",
492 layer4_name(l4type), host? host : (passive?
493 "[loopback]" : "[localhost]"), port_number);
499 * Create a passive / listening socket.
501 * \param l4type The transport-layer type (\p IPPROTO_xxx).
502 * \param port The decimal port number to listen on.
503 * \param fo Flowopts (if any) to set before starting to listen.
505 * \return Positive integer (socket descriptor) on success, negative value
508 * \sa makesock(), ip(7), ipv6(7), bind(2), listen(2).
510 int para_listen(unsigned l4type, uint16_t port, struct flowopts *fo)
512 int ret, fd = makesock(l4type, 1, NULL, port, fo);
515 ret = listen(fd, BACKLOG);
519 return -ERRNO_TO_PARA_ERROR(ret);
521 PARA_INFO_LOG("listening on %s port %u, fd %d\n",
522 layer4_name(l4type), port, fd);
528 * Determine IPv4/v6 socket address length.
529 * \param sa Container of IPv4 or IPv6 address.
530 * \return Address-family dependent address length.
532 static socklen_t salen(const struct sockaddr *sa)
534 assert(sa->sa_family == AF_INET || sa->sa_family == AF_INET6);
536 return sa->sa_family == AF_INET6
537 ? sizeof(struct sockaddr_in6)
538 : sizeof(struct sockaddr_in);
541 /** True if @ss holds a v6-mapped-v4 address (RFC 4291, 2.5.5.2) */
542 static bool SS_IS_ADDR_V4MAPPED(const struct sockaddr_storage *ss)
544 const struct sockaddr_in6 *ia6 = (const struct sockaddr_in6 *)ss;
546 return ss->ss_family == AF_INET6 && IN6_IS_ADDR_V4MAPPED(&ia6->sin6_addr);
550 * Process IPv4/v6 address, turn v6-mapped-v4 address into normal IPv4 address.
551 * \param ss Container of IPv4/6 address.
552 * \return Pointer to normalized address (may be static storage).
556 static const struct sockaddr *
557 normalize_ip_address(const struct sockaddr_storage *ss)
559 assert(ss->ss_family == AF_INET || ss->ss_family == AF_INET6);
561 if (SS_IS_ADDR_V4MAPPED(ss)) {
562 const struct sockaddr_in6 *ia6 = (const struct sockaddr_in6 *)ss;
563 static struct sockaddr_in ia;
565 ia.sin_family = AF_INET;
566 ia.sin_port = ia6->sin6_port;
567 memcpy(&ia.sin_addr.s_addr, &(ia6->sin6_addr.s6_addr[12]), 4);
568 return (const struct sockaddr *)&ia;
570 return (const struct sockaddr *)ss;
574 * Generic/fallback MTU values
576 * These are taken from RFC 1122, RFC 2460, and RFC 5405.
577 * - RFC 1122, 3.3.3 defines EMTU_S ("Effective MTU for sending") and recommends
578 * to use an EMTU_S size of of 576 bytes if the IPv4 path MTU is unknown;
579 * - RFC 2460, 5. requires a minimum IPv6 MTU of 1280 bytes;
580 * - RFC 5405, 3.2 recommends that if path MTU discovery is not done,
581 * UDP senders should use the respective minimum values of EMTU_S.
583 static inline int generic_mtu(const int af_type)
585 return af_type == AF_INET6 ? 1280 : 576;
588 /** Crude approximation of IP header overhead - neglecting options. */
589 static inline int estimated_header_overhead(const int af_type)
591 return af_type == AF_INET6 ? 40 : 20;
595 * Get the maximum transport-layer message size (MMS_S).
597 * \param sockfd The socket file descriptor.
599 * The socket must be connected. See RFC 1122, 3.3.3. If the protocol family
600 * could not be determined, \p AF_INET is assumed.
602 * \return The maximum message size of the address family type.
604 int generic_max_transport_msg_size(int sockfd)
606 struct sockaddr_storage ss = {.ss_family = 0};
607 socklen_t sslen = sizeof(ss);
608 int af_type = AF_INET;
610 if (getpeername(sockfd, (struct sockaddr *)&ss, &sslen) < 0) {
611 PARA_ERROR_LOG("can not determine remote address type: %s\n",
613 } else if (!SS_IS_ADDR_V4MAPPED(&ss)) {
614 af_type = ss.ss_family;
616 return generic_mtu(af_type) - estimated_header_overhead(af_type);
620 * Look up the remote side of a connected socket structure.
622 * \param fd The socket descriptor of the connected socket.
624 * \return A static character string identifying hostname and port of the
625 * chosen side in numeric host:port format.
627 * \sa getsockname(2), getpeername(2), parse_url(), getnameinfo(3),
628 * services(5), nsswitch.conf(5).
630 char *remote_name(int fd)
632 struct sockaddr_storage ss = {.ss_family = 0};
633 const struct sockaddr *sa;
634 socklen_t sslen = sizeof(ss);
635 char hbuf[NI_MAXHOST], sbuf[NI_MAXSERV];
636 static char output[sizeof(hbuf) + sizeof(sbuf) + 4];
639 if (getpeername(fd, (struct sockaddr *)&ss, &sslen) < 0) {
640 PARA_ERROR_LOG("can not determine address from fd %d: %s\n",
641 fd, strerror(errno));
642 snprintf(output, sizeof(output), "(unknown)");
645 sa = normalize_ip_address(&ss);
646 ret = getnameinfo(sa, salen(sa), hbuf, sizeof(hbuf), sbuf,
647 sizeof(sbuf), NI_NUMERICHOST | NI_NUMERICSERV);
649 PARA_WARNING_LOG("hostname lookup error (%s).\n",
651 snprintf(output, sizeof(output), "(lookup error)");
652 } else if (sa->sa_family == AF_INET6)
653 snprintf(output, sizeof(output), "[%s]:%s", hbuf, sbuf);
655 snprintf(output, sizeof(output), "%s:%s", hbuf, sbuf);
660 * Extract IPv4 or IPv6-mapped-IPv4 address from sockaddr_storage.
662 * \param ss Container of IPv4/6 address.
663 * \param ia Extracted IPv4 address (different from 0) or 0 if unsuccessful.
667 void extract_v4_addr(const struct sockaddr_storage *ss, struct in_addr *ia)
669 const struct sockaddr *sa = normalize_ip_address(ss);
671 memset(ia, 0, sizeof(*ia));
672 if (sa->sa_family == AF_INET)
673 *ia = ((struct sockaddr_in *)sa)->sin_addr;
677 * Compare the address part of IPv4/6 addresses.
679 * \param sa1 First address.
680 * \param sa2 Second address.
682 * \return True iff the IP address of \a sa1 and \a sa2 match.
684 bool sockaddr_equal(const struct sockaddr *sa1, const struct sockaddr *sa2)
688 if (sa1->sa_family != sa2->sa_family)
690 if (sa1->sa_family == AF_INET) {
691 struct sockaddr_in *a1 = (typeof(a1))sa1,
692 *a2 = (typeof (a2))sa2;
693 return a1->sin_addr.s_addr == a2->sin_addr.s_addr;
694 } else if (sa1->sa_family == AF_INET6) {
695 struct sockaddr_in6 *a1 = (typeof(a1))sa1,
696 *a2 = (typeof (a2))sa2;
697 return !memcmp(a1, a2, sizeof(*a1));
703 * Receive data from a file descriptor.
705 * \param fd The file descriptor.
706 * \param buf The buffer to write the data to.
707 * \param size The size of \a buf.
709 * Receive at most \a size bytes from file descriptor \a fd.
711 * \return The number of bytes received on success, negative on errors, zero if
712 * the peer has performed an orderly shutdown.
716 __must_check int recv_bin_buffer(int fd, char *buf, size_t size)
720 n = recv(fd, buf, size, 0);
722 return -ERRNO_TO_PARA_ERROR(errno);
727 * Receive and write terminating NULL byte.
729 * \param fd The file descriptor.
730 * \param buf The buffer to write the data to.
731 * \param size The size of \a buf.
733 * Read at most \a size - 1 bytes from file descriptor \a fd and
734 * write a NULL byte at the end of the received data.
736 * \return The return value of the underlying call to \a recv_bin_buffer().
738 * \sa recv_bin_buffer()
740 int recv_buffer(int fd, char *buf, size_t size)
745 n = recv_bin_buffer(fd, buf, size - 1);
754 * Wrapper around the accept system call.
756 * \param fd The listening socket.
757 * \param rfds An optional fd_set pointer.
758 * \param addr Structure which is filled in with the address of the peer socket.
759 * \param size Should contain the size of the structure pointed to by \a addr.
760 * \param new_fd Result pointer.
762 * Accept incoming connections on \a addr, retry if interrupted. If \a rfds is
763 * not \p NULL, return 0 if \a fd is not set in \a rfds without calling accept().
765 * \return Negative on errors, zero if no connections are present to be accepted,
770 int para_accept(int fd, fd_set *rfds, void *addr, socklen_t size, int *new_fd)
774 if (rfds && !FD_ISSET(fd, rfds))
777 ret = accept(fd, (struct sockaddr *) addr, &size);
778 while (ret < 0 && errno == EINTR);
784 if (errno == EAGAIN || errno == EWOULDBLOCK)
786 return -ERRNO_TO_PARA_ERROR(errno);
790 * Probe the list of DCCP CCIDs configured on this host.
791 * \param ccid_array Pointer to return statically allocated array in.
792 * \return Number of elements returned in \a ccid_array or error.
794 * NB: This feature is only available on Linux > 2.6.30; on older kernels
795 * ENOPROTOOPT ("Protocol not available") will be returned.
797 int dccp_available_ccids(uint8_t **ccid_array)
799 static uint8_t ccids[DCCP_MAX_HOST_CCIDS];
800 socklen_t nccids = sizeof(ccids);
803 ret = fd = makesock(IPPROTO_DCCP, 1, NULL, 0, NULL);
807 if (getsockopt(fd, SOL_DCCP, DCCP_SOCKOPT_AVAILABLE_CCIDS,
808 ccids, &nccids) < 0) {
811 PARA_ERROR_LOG("No DCCP_SOCKOPT_AVAILABLE_CCIDS: %s\n",
813 return -ERRNO_TO_PARA_ERROR(ret);
822 * Prepare a structure for AF_UNIX socket addresses.
824 * This just copies name to the sun_path component of u, prepending a zero byte
825 * if abstract sockets are supported.
827 * The first call to this function tries to bind a socket to the abstract name
828 * space. The result of this test is stored in a static variable. Subsequent
829 * calls read this variable and create abstract sockets on systems that support
832 static int init_unix_addr(struct sockaddr_un *u, const char *name)
834 static int use_abstract;
836 if (strlen(name) + 1 >= UNIX_PATH_MAX)
837 return -E_NAME_TOO_LONG;
838 memset(u->sun_path, 0, UNIX_PATH_MAX);
839 u->sun_family = PF_UNIX;
840 if (use_abstract == 0) { /* executed only once */
841 int fd = socket(PF_UNIX, SOCK_STREAM, 0);
842 memcpy(u->sun_path, "\0x\0", 3);
843 if (bind(fd, (struct sockaddr *)u, sizeof(*u)) == 0)
844 use_abstract = 1; /* yes */
846 use_abstract = -1; /* no */
848 PARA_NOTICE_LOG("%susing abstract socket namespace\n",
849 use_abstract == 1? "" : "not ");
851 strcpy(u->sun_path + (use_abstract == 1? 1 : 0), name);
856 * Create a socket for local communication and listen on it.
858 * \param name The socket pathname.
860 * This function creates a passive local socket for sequenced, reliable,
861 * two-way, connection-based byte streams. The socket file descriptor is set to
862 * nonblocking mode and listen(2) is called to prepare the socket for
863 * accepting incoming connection requests.
865 * \return The file descriptor on success, negative error code on failure.
867 * \sa socket(2), \sa bind(2), \sa chmod(2), listen(2), unix(7).
869 int create_local_socket(const char *name)
871 struct sockaddr_un unix_addr;
874 ret = init_unix_addr(&unix_addr, name);
877 ret = socket(PF_UNIX, SOCK_STREAM, 0);
879 return -ERRNO_TO_PARA_ERROR(errno);
881 ret = mark_fd_nonblocking(fd);
884 ret = bind(fd, (struct sockaddr *)&unix_addr, sizeof(unix_addr));
886 ret = -ERRNO_TO_PARA_ERROR(errno);
889 if (unix_addr.sun_path[0] != 0) { /* pathname socket */
890 mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP
893 if (chmod(name, mode) < 0)
896 if (listen(fd , 5) < 0) {
897 ret = -ERRNO_TO_PARA_ERROR(errno);
907 * Prepare, create, and connect to a Unix domain socket for local communication.
909 * \param name The socket pathname.
911 * This function creates a local socket for sequenced, reliable, two-way,
912 * connection-based byte streams.
914 * \return The file descriptor of the connected socket on success, negative on
917 * \sa create_local_socket(), unix(7), connect(2).
919 int connect_local_socket(const char *name)
921 struct sockaddr_un unix_addr;
924 PARA_DEBUG_LOG("connecting to %s\n", name);
925 fd = socket(PF_UNIX, SOCK_STREAM, 0);
927 return -ERRNO_TO_PARA_ERROR(errno);
928 ret = init_unix_addr(&unix_addr, name);
931 if (connect(fd, (struct sockaddr *)&unix_addr, sizeof(unix_addr)) != -1)
933 ret = -ERRNO_TO_PARA_ERROR(errno);
940 ssize_t send_cred_buffer(int sock, char *buf)
942 return write_buffer(sock, buf);
944 int recv_cred_buffer(int fd, char *buf, size_t size)
946 return recv_buffer(fd, buf, size) > 0? 1 : -E_RECVMSG;
948 #else /* HAVE_UCRED */
951 * Send a buffer and the credentials of the current process to a socket.
953 * \param sock The file descriptor of the sending socket.
954 * \param buf The zero-terminated buffer to send.
956 * \return On success, this call returns the number of bytes sent. On errors,
957 * \p -E_SENDMSG is returned.
959 * \sa \ref recv_cred_buffer, sendmsg(2), socket(7), unix(7), okir's Black Hats
962 ssize_t send_cred_buffer(int sock, char *buf)
964 char control[sizeof(struct cmsghdr) + sizeof(struct ucred)];
966 struct cmsghdr *cmsg;
967 static struct iovec iov;
973 iov.iov_len = strlen(buf);
977 /* compose the message */
978 memset(&msg, 0, sizeof(msg));
981 msg.msg_control = control;
982 msg.msg_controllen = sizeof(control);
983 /* attach the ucred struct */
984 cmsg = CMSG_FIRSTHDR(&msg);
985 cmsg->cmsg_level = SOL_SOCKET;
986 cmsg->cmsg_type = SCM_CREDENTIALS;
987 cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred));
988 *(struct ucred *)CMSG_DATA(cmsg) = c;
989 msg.msg_controllen = cmsg->cmsg_len;
990 ret = sendmsg(sock, &msg, 0);
996 static void dispose_fds(int *fds, unsigned num)
1000 for (i = 0; i < num; i++)
1005 * Receive a buffer and the Unix credentials of the sending process.
1007 * \param fd The file descriptor of the receiving socket.
1008 * \param buf The buffer to store the received message.
1009 * \param size The length of \a buf in bytes.
1011 * \return Negative on errors, the user id of the sending process on success.
1013 * \sa \ref send_cred_buffer and the references given there.
1015 int recv_cred_buffer(int fd, char *buf, size_t size)
1017 char control[255] __a_aligned(8);
1019 struct cmsghdr *cmsg;
1025 setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &yes, sizeof(int));
1026 memset(&msg, 0, sizeof(msg));
1027 memset(buf, 0, size);
1032 msg.msg_control = control;
1033 msg.msg_controllen = sizeof(control);
1034 if (recvmsg(fd, &msg, 0) < 0)
1036 result = -E_SCM_CREDENTIALS;
1037 cmsg = CMSG_FIRSTHDR(&msg);
1039 if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type
1040 == SCM_CREDENTIALS) {
1041 memcpy(&cred, CMSG_DATA(cmsg), sizeof(struct ucred));
1044 if (cmsg->cmsg_level == SOL_SOCKET
1045 && cmsg->cmsg_type == SCM_RIGHTS) {
1046 dispose_fds((int *)CMSG_DATA(cmsg),
1047 (cmsg->cmsg_len - CMSG_LEN(0))
1050 cmsg = CMSG_NXTHDR(&msg, cmsg);
1054 #endif /* HAVE_UCRED */