2 * Copyright (C) 2005-2011 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
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 succesful, 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 NULL if failed.
146 * If NULL is returned, \a host and \a portnum are undefined. If no
147 * port number was present in \a url, \a portnum 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
++)
177 if (para_atoi32(++o
, port
) < 0 ||
178 *port
< 0 || *port
> 0xffff)
181 if (host_string_ok(host
))
189 * 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
), "%u", 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
;
267 struct flowopts
*flowopt_new(void)
269 struct flowopts
*new = para_malloc(sizeof(*new));
271 INIT_LIST_HEAD(&new->sockopts
);
276 * Append new socket option to flowopt queue.
278 * \param fo The flowopt queue to append to.
279 * \param lev Level at which \a opt resides.
280 * \param opt New option to add.
281 * \param name Stringified name of \a opt.
282 * \param val The value to set \a opt to.
283 * \param len Length of \a val.
287 void flowopt_add(struct flowopts
*fo
, int lev
, int opt
,
288 const char *name
, const void *val
, int len
)
290 struct pre_conn_opt
*new = para_malloc(sizeof(*new));
292 new->sock_option
= opt
;
293 new->sock_level
= lev
;
294 new->opt_name
= para_strdup(name
);
300 new->opt_val
= para_malloc(len
);
302 memcpy(new->opt_val
, val
, len
);
305 list_add_tail(&new->node
, &fo
->sockopts
);
308 void flowopt_add_bool(struct flowopts
*fo
, int lev
, int opt
,
309 const char *optname
, bool on_or_off
)
311 int on
= on_or_off
; /* kernel takes 'int' */
313 flowopt_add(fo
, lev
, opt
, optname
, &on
, sizeof(on
));
316 /** Set the entire bunch of pre-connection options at once. */
317 static void flowopt_setopts(int sockfd
, struct flowopts
*fo
)
319 struct pre_conn_opt
*pc
;
324 list_for_each_entry(pc
, &fo
->sockopts
, node
)
325 if (setsockopt(sockfd
, pc
->sock_level
, pc
->sock_option
,
326 pc
->opt_val
, pc
->opt_len
) < 0) {
327 PARA_EMERG_LOG("Can not set %s socket option: %s",
328 pc
->opt_name
, strerror(errno
));
333 static void flowopt_cleanup(struct flowopts
*fo
)
335 struct pre_conn_opt
*cur
, *next
;
340 list_for_each_entry_safe(cur
, next
, &fo
->sockopts
, node
) {
349 * Resolve IPv4/IPv6 address and create a ready-to-use active or passive socket.
351 * \param l4type The layer-4 type (\p IPPROTO_xxx).
352 * \param passive Whether this is a passive (1) or active (0) socket.
353 * \param host Remote or local hostname or IPv/6 address string.
354 * \param port_number Decimal port number.
355 * \param fo Socket options to be set before making the connection.
357 * This creates a ready-made IPv4/v6 socket structure after looking up the
358 * necessary parameters. The interpretation of \a host depends on the value of
360 * - on a passive socket host is interpreted as an interface IPv4/6 address
361 * (can be left NULL);
362 * - on an active socket, \a host is the peer DNS name or IPv4/6 address
364 * - \a port_number is in either case the numeric port number (not service
367 * Furthermore, bind(2) is called on passive sockets, and connect(2) on active
368 * sockets. The algorithm tries all possible address combinations until it
369 * succeeds. If \a fo is supplied, options are set and cleanup is performed.
371 * \return This function returns 1 on success and \a -E_ADDRESS_LOOKUP when no
372 * matching connection could be set up (with details in the error log).
374 * \sa ipv6(7), getaddrinfo(3), bind(2), connect(2).
376 int makesock(unsigned l4type
, bool passive
,
377 const char *host
, uint16_t port_number
,
380 struct addrinfo
*local
= NULL
, *src
= NULL
, *remote
= NULL
,
382 unsigned int l3type
= AF_UNSPEC
;
383 int rc
, on
= 1, sockfd
= -1,
384 socktype
= sock_type(l4type
);
385 char port
[6]; /* port number has at most 5 digits */
387 sprintf(port
, "%u", port_number
);
388 /* Set up address hint structure */
389 memset(&hints
, 0, sizeof(hints
));
390 hints
.ai_family
= l3type
;
391 hints
.ai_socktype
= socktype
;
393 * getaddrinfo does not support SOCK_DCCP, so for the sake of lookup
394 * (and only then) pretend to be UDP.
396 if (l4type
== IPPROTO_DCCP
)
397 hints
.ai_socktype
= SOCK_DGRAM
;
399 /* only use addresses available on the host */
400 hints
.ai_flags
= AI_ADDRCONFIG
;
401 if (l3type
== AF_INET6
)
402 /* use v4-mapped-v6 if no v6 addresses found */
403 hints
.ai_flags
|= AI_V4MAPPED
| AI_ALL
;
405 if (passive
&& host
== NULL
)
406 hints
.ai_flags
|= AI_PASSIVE
;
408 /* Obtain local/remote address information */
409 if ((rc
= getaddrinfo(host
, port
, &hints
, passive
? &local
: &remote
))) {
410 PARA_ERROR_LOG("can not resolve %s address %s#%s: %s.\n",
412 host
? host
: (passive
? "[loopback]" : "[localhost]"),
413 port
, gai_strerror(rc
));
414 rc
= -E_ADDRESS_LOOKUP
;
418 /* Iterate over all src/dst combination, exhausting dst first */
419 for (src
= local
, dst
= remote
; src
!= NULL
|| dst
!= NULL
; /* no op */ ) {
420 if (src
&& dst
&& src
->ai_family
== AF_INET
421 && dst
->ai_family
== AF_INET6
)
422 goto get_next_dst
; /* v4 -> v6 is not possible */
424 sockfd
= socket(src
? src
->ai_family
: dst
->ai_family
,
430 * Reuse the address on passive sockets to avoid failure on
431 * restart (protocols using listen()) and when creating
432 * multiple listener instances (UDP multicast).
434 if (passive
&& setsockopt(sockfd
, SOL_SOCKET
, SO_REUSEADDR
,
435 &on
, sizeof(on
)) == -1) {
438 PARA_ERROR_LOG("can not set SO_REUSEADDR: %s\n",
440 rc
= -ERRNO_TO_PARA_ERROR(rc
);
443 flowopt_setopts(sockfd
, fo
);
446 if (bind(sockfd
, src
->ai_addr
, src
->ai_addrlen
) < 0) {
450 if (!dst
) /* bind-only completed successfully */
454 if (dst
&& connect(sockfd
, dst
->ai_addr
, dst
->ai_addrlen
) == 0)
455 break; /* connection completed successfully */
458 if (dst
&& (dst
= dst
->ai_next
))
461 if (src
&& (src
= src
->ai_next
)) /* restart inner loop */
468 freeaddrinfo(remote
);
471 if (src
== NULL
&& dst
== NULL
) {
474 PARA_ERROR_LOG("can not create %s socket %s#%s.\n",
475 layer4_name(l4type
), host
? host
: (passive
?
476 "[loopback]" : "[localhost]"), port
);
483 * Create a passive / listening socket.
485 * \param l4type The transport-layer type (\p IPPROTO_xxx).
486 * \param port The decimal port number to listen on.
487 * \param fo Flowopts (if any) to set before starting to listen.
489 * \return Positive integer (socket descriptor) on success, negative value
492 * \sa makesock(), ip(7), ipv6(7), bind(2), listen(2).
494 int para_listen(unsigned l4type
, uint16_t port
, struct flowopts
*fo
)
496 int ret
, fd
= makesock(l4type
, 1, NULL
, port
, fo
);
499 ret
= listen(fd
, BACKLOG
);
503 return -ERRNO_TO_PARA_ERROR(ret
);
505 PARA_INFO_LOG("listening on %s port %u, fd %d\n",
506 layer4_name(l4type
), port
, fd
);
512 * Determine IPv4/v6 socket address length.
513 * \param sa Container of IPv4 or IPv6 address.
514 * \return Address-family dependent address length.
516 static socklen_t
salen(const struct sockaddr
*sa
)
518 assert(sa
->sa_family
== AF_INET
|| sa
->sa_family
== AF_INET6
);
520 return sa
->sa_family
== AF_INET6
521 ? sizeof(struct sockaddr_in6
)
522 : sizeof(struct sockaddr_in
);
525 /** True if @ss holds a v6-mapped-v4 address (RFC 4291, 2.5.5.2) */
526 static bool SS_IS_ADDR_V4MAPPED(const struct sockaddr_storage
*ss
)
528 const struct sockaddr_in6
*ia6
= (const struct sockaddr_in6
*)ss
;
530 return ss
->ss_family
== AF_INET6
&& IN6_IS_ADDR_V4MAPPED(&ia6
->sin6_addr
);
534 * Process IPv4/v6 address, turn v6-mapped-v4 address into normal IPv4 address.
535 * \param ss Container of IPv4/6 address.
536 * \return Pointer to normalized address (may be static storage).
540 static const struct sockaddr
*
541 normalize_ip_address(const struct sockaddr_storage
*ss
)
543 assert(ss
->ss_family
== AF_INET
|| ss
->ss_family
== AF_INET6
);
545 if (SS_IS_ADDR_V4MAPPED(ss
)) {
546 const struct sockaddr_in6
*ia6
= (const struct sockaddr_in6
*)ss
;
547 static struct sockaddr_in ia
;
549 ia
.sin_family
= AF_INET
;
550 ia
.sin_port
= ia6
->sin6_port
;
551 memcpy(&ia
.sin_addr
.s_addr
, &(ia6
->sin6_addr
.s6_addr
[12]), 4);
552 return (const struct sockaddr
*)&ia
;
554 return (const struct sockaddr
*)ss
;
558 * Generic/fallback MTU values
560 * These are taken from RFC 1122, RFC 2460, and RFC 5405.
561 * - RFC 1122, 3.3.3 defines EMTU_S ("Effective MTU for sending") and recommends
562 * to use an EMTU_S size of of 576 bytes if the IPv4 path MTU is unknown;
563 * - RFC 2460, 5. requires a minimum IPv6 MTU of 1280 bytes;
564 * - RFC 5405, 3.2 recommends that if path MTU discovery is not done,
565 * UDP senders should use the respective minimum values of EMTU_S.
567 static inline int generic_mtu(const int af_type
)
569 return af_type
== AF_INET6
? 1280 : 576;
572 /** Crude approximation of IP header overhead - neglecting options. */
573 static inline int estimated_header_overhead(const int af_type
)
575 return af_type
== AF_INET6
? 40 : 20;
579 * Maximum transport-layer message size (MMS_S) as per RFC 1122, 3.3.3
580 * Socket must be connected.
582 int generic_max_transport_msg_size(int sockfd
)
584 struct sockaddr_storage ss
;
585 socklen_t sslen
= sizeof(ss
);
586 int af_type
= AF_INET
;
588 if (getpeername(sockfd
, (struct sockaddr
*)&ss
, &sslen
) < 0) {
589 PARA_ERROR_LOG("can not determine remote address type: %s\n",
591 } else if (!SS_IS_ADDR_V4MAPPED(&ss
)) {
592 af_type
= ss
.ss_family
;
594 return generic_mtu(af_type
) - estimated_header_overhead(af_type
);
598 * Look up the local or remote side of a connected socket structure.
600 * \param fd The socket descriptor of the connected socket.
601 * \param getname Either \p getsockname() for local, or \p getpeername() for
604 * \return A static character string identifying hostname and port of the
605 * chosen side in numeric host:port format.
607 * \sa getsockname(2), getpeername(2), parse_url(), getnameinfo(3),
608 * services(5), nsswitch.conf(5).
610 static char *__get_sock_name(int fd
, int (*getname
)(int, struct sockaddr
*,
613 struct sockaddr_storage ss
;
614 const struct sockaddr
*sa
;
615 socklen_t sslen
= sizeof(ss
);
616 char hbuf
[NI_MAXHOST
], sbuf
[NI_MAXSERV
];
617 static char output
[sizeof(hbuf
) + sizeof(sbuf
) + 4];
620 if (getname(fd
, (struct sockaddr
*)&ss
, &sslen
) < 0) {
621 PARA_ERROR_LOG("can not determine address from fd %d: %s\n",
622 fd
, strerror(errno
));
623 snprintf(output
, sizeof(output
), "(unknown)");
626 sa
= normalize_ip_address(&ss
);
627 ret
= getnameinfo(sa
, salen(sa
), hbuf
, sizeof(hbuf
), sbuf
,
628 sizeof(sbuf
), NI_NUMERICHOST
| NI_NUMERICSERV
);
630 PARA_WARNING_LOG("hostname lookup error (%s).\n",
632 snprintf(output
, sizeof(output
), "(lookup error)");
633 } else if (sa
->sa_family
== AF_INET6
)
634 snprintf(output
, sizeof(output
), "[%s]:%s", hbuf
, sbuf
);
636 snprintf(output
, sizeof(output
), "%s:%s", hbuf
, sbuf
);
641 * Look up the local side of a connected socket structure.
643 * \param sockfd The file descriptor of the socket.
645 * \return A pointer to a static buffer containing hostname an port. This
646 * buffer must not be freed by the caller.
650 char *local_name(int sockfd
)
652 return __get_sock_name(sockfd
, getsockname
);
656 * Look up the remote side of a connected socket structure.
658 * \param sockfd The file descriptor of the socket.
660 * \return Analogous to the return value of \ref local_name() but for the
665 char *remote_name(int sockfd
)
667 return __get_sock_name(sockfd
, getpeername
);
671 * Extract IPv4 or IPv6-mapped-IPv4 address from sockaddr_storage.
672 * \param ss Container of IPv4/6 address
673 * \return Extracted IPv4 address (different from 0) or 0 if unsuccessful.
677 struct in_addr
extract_v4_addr(const struct sockaddr_storage
*ss
)
679 struct in_addr ia
= {.s_addr
= 0};
680 const struct sockaddr
*sa
= normalize_ip_address(ss
);
682 if (sa
->sa_family
== AF_INET
)
683 ia
= ((struct sockaddr_in
*)sa
)->sin_addr
;
688 * Send a binary buffer.
690 * \param fd The file descriptor.
691 * \param buf The buffer to be sent.
692 * \param len The length of \a buf.
694 * Send out the buffer and try to resend the remaining part in case of short
699 int send_bin_buffer(int fd
, const char *buf
, size_t len
)
702 PARA_CRIT_LOG("len == 0\n");
703 return write_all(fd
, buf
, &len
);
707 * Send a \p NULL-terminated buffer.
709 * \param fd The file descriptor.
710 * \param buf The null-terminated buffer to be send.
712 * This is equivalent to send_bin_buffer(fd, buf, strlen(buf)).
716 int send_buffer(int fd
, const char *buf
)
718 return send_bin_buffer(fd
, buf
, strlen(buf
));
722 * Send a buffer given by a format string.
724 * \param fd The file descriptor.
725 * \param fmt A format string.
729 __printf_2_3
int send_va_buffer(int fd
, const char *fmt
, ...)
734 PARA_VSPRINTF(fmt
, msg
);
735 ret
= send_buffer(fd
, msg
);
741 * Receive data from a file descriptor.
743 * \param fd The file descriptor.
744 * \param buf The buffer to write the data to.
745 * \param size The size of \a buf.
747 * Receive at most \a size bytes from file descriptor \a fd.
749 * \return The number of bytes received on success, negative on errors, zero if
750 * the peer has performed an orderly shutdown.
754 __must_check
int recv_bin_buffer(int fd
, char *buf
, size_t size
)
758 n
= recv(fd
, buf
, size
, 0);
760 return -ERRNO_TO_PARA_ERROR(errno
);
765 * Receive and write terminating NULL byte.
767 * \param fd The file descriptor.
768 * \param buf The buffer to write the data to.
769 * \param size The size of \a buf.
771 * Read at most \a size - 1 bytes from file descriptor \a fd and
772 * write a NULL byte at the end of the received data.
774 * \return The return value of the underlying call to \a recv_bin_buffer().
776 * \sa recv_bin_buffer()
778 int recv_buffer(int fd
, char *buf
, size_t size
)
783 n
= recv_bin_buffer(fd
, buf
, size
- 1);
792 * Wrapper around the accept system call.
794 * \param fd The listening socket.
795 * \param rfds An optional fd_set pointer.
796 * \param addr Structure which is filled in with the address of the peer socket.
797 * \param size Should contain the size of the structure pointed to by \a addr.
798 * \param new_fd Result pointer.
800 * Accept incoming connections on \a addr, retry if interrupted. If \a rfds is
801 * not \p NULL, return 0 if \a fd is not set in \a rfds without calling accept().
803 * \return Negative on errors, zero if no connections are present to be accepted,
808 int para_accept(int fd
, fd_set
*rfds
, void *addr
, socklen_t size
, int *new_fd
)
812 if (rfds
&& !FD_ISSET(fd
, rfds
))
815 ret
= accept(fd
, (struct sockaddr
*) addr
, &size
);
816 while (ret
< 0 && errno
== EINTR
);
822 if (errno
== EAGAIN
|| errno
== EWOULDBLOCK
)
824 return -ERRNO_TO_PARA_ERROR(errno
);
828 * Probe the list of DCCP CCIDs configured on this host.
829 * \param ccid_array Pointer to return statically allocated array in.
830 * \return Number of elements returned in \a ccid_array or error.
832 * NB: This feature is only available on Linux > 2.6.30; on older kernels
833 * ENOPROTOOPT ("Protocol not available") will be returned.
835 int dccp_available_ccids(uint8_t **ccid_array
)
837 static uint8_t ccids
[DCCP_MAX_HOST_CCIDS
];
838 socklen_t nccids
= sizeof(ccids
);
841 ret
= fd
= makesock(IPPROTO_DCCP
, 1, NULL
, 0, NULL
);
845 if (getsockopt(fd
, SOL_DCCP
, DCCP_SOCKOPT_AVAILABLE_CCIDS
,
846 ccids
, &nccids
) < 0) {
849 PARA_ERROR_LOG("No DCCP_SOCKOPT_AVAILABLE_CCIDS: %s\n",
851 return -ERRNO_TO_PARA_ERROR(ret
);
860 * Prepare a structure for \p AF_UNIX socket addresses.
862 * \param u Pointer to the struct to be prepared.
863 * \param name The socket pathname.
865 * This just copies \a name to the sun_path component of \a u.
867 * \return Positive on success, \p -E_NAME_TOO_LONG if \a name is longer
868 * than \p UNIX_PATH_MAX.
870 static int init_unix_addr(struct sockaddr_un
*u
, const char *name
)
872 if (strlen(name
) >= UNIX_PATH_MAX
)
873 return -E_NAME_TOO_LONG
;
874 memset(u
->sun_path
, 0, UNIX_PATH_MAX
);
875 u
->sun_family
= PF_UNIX
;
876 strcpy(u
->sun_path
, name
);
881 * Prepare, create, and bind a socket for local communication.
883 * \param name The socket pathname.
884 * \param unix_addr Pointer to the \p AF_UNIX socket structure.
885 * \param mode The desired mode of the socket.
887 * This function creates a local socket for sequenced, reliable,
888 * two-way, connection-based byte streams.
890 * \return The file descriptor, on success, negative on errors.
896 int create_local_socket(const char *name
, struct sockaddr_un
*unix_addr
,
901 ret
= init_unix_addr(unix_addr
, name
);
904 ret
= socket(PF_UNIX
, SOCK_STREAM
, 0);
906 return -ERRNO_TO_PARA_ERROR(errno
);
908 ret
= bind(fd
, (struct sockaddr
*) unix_addr
, UNIX_PATH_MAX
);
910 ret
= -ERRNO_TO_PARA_ERROR(errno
);
914 if (chmod(name
, mode
) < 0)
923 * Prepare, create, and connect to a Unix domain socket for local communication.
925 * \param name The socket pathname.
927 * This function creates a local socket for sequenced, reliable, two-way,
928 * connection-based byte streams.
930 * \return The file descriptor of the connected socket on success, negative on
933 * \sa create_local_socket(), unix(7), connect(2).
935 int connect_local_socket(const char *name
)
937 struct sockaddr_un unix_addr
;
940 PARA_DEBUG_LOG("connecting to %s\n", name
);
941 ret
= init_unix_addr(&unix_addr
, name
);
944 fd
= socket(PF_UNIX
, SOCK_STREAM
, 0);
946 return -ERRNO_TO_PARA_ERROR(errno
);
947 if (connect(fd
, (struct sockaddr
*)&unix_addr
, sizeof(unix_addr
)) == -1) {
948 ret
= -ERRNO_TO_PARA_ERROR(errno
);
958 ssize_t
send_cred_buffer(int sock
, char *buf
)
960 return send_buffer(sock
, buf
);
962 int recv_cred_buffer(int fd
, char *buf
, size_t size
)
964 return recv_buffer(fd
, buf
, size
) > 0? 1 : -E_RECVMSG
;
966 #else /* HAVE_UCRED */
968 * Send \p NULL-terminated buffer and Unix credentials of the current process.
970 * \param sock The socket file descriptor.
971 * \param buf The buffer to be sent.
973 * \return On success, this call returns the number of characters sent. On
974 * error, \p -E_SENDMSG is returned.
976 * \sa sendmsg(2), okir's Black Hats Manual.
978 ssize_t
send_cred_buffer(int sock
, char *buf
)
980 char control
[sizeof(struct cmsghdr
) + sizeof(struct ucred
)];
982 struct cmsghdr
*cmsg
;
983 static struct iovec iov
;
989 iov
.iov_len
= strlen(buf
);
993 /* compose the message */
994 memset(&msg
, 0, sizeof(msg
));
997 msg
.msg_control
= control
;
998 msg
.msg_controllen
= sizeof(control
);
999 /* attach the ucred struct */
1000 cmsg
= CMSG_FIRSTHDR(&msg
);
1001 cmsg
->cmsg_level
= SOL_SOCKET
;
1002 cmsg
->cmsg_type
= SCM_CREDENTIALS
;
1003 cmsg
->cmsg_len
= CMSG_LEN(sizeof(struct ucred
));
1004 *(struct ucred
*)CMSG_DATA(cmsg
) = c
;
1005 msg
.msg_controllen
= cmsg
->cmsg_len
;
1006 ret
= sendmsg(sock
, &msg
, 0);
1012 static void dispose_fds(int *fds
, unsigned num
)
1016 for (i
= 0; i
< num
; i
++)
1021 * Receive a buffer and the Unix credentials of the sending process.
1023 * \param fd the socket file descriptor.
1024 * \param buf the buffer to store the message.
1025 * \param size the size of \a buffer.
1027 * \return negative on errors, the user id on success.
1029 * \sa recvmsg(2), okir's Black Hats Manual.
1031 int recv_cred_buffer(int fd
, char *buf
, size_t size
)
1035 struct cmsghdr
*cmsg
;
1041 setsockopt(fd
, SOL_SOCKET
, SO_PASSCRED
, &yes
, sizeof(int));
1042 memset(&msg
, 0, sizeof(msg
));
1043 memset(buf
, 0, size
);
1048 msg
.msg_control
= control
;
1049 msg
.msg_controllen
= sizeof(control
);
1050 if (recvmsg(fd
, &msg
, 0) < 0)
1052 result
= -E_SCM_CREDENTIALS
;
1053 cmsg
= CMSG_FIRSTHDR(&msg
);
1055 if (cmsg
->cmsg_level
== SOL_SOCKET
&& cmsg
->cmsg_type
1056 == SCM_CREDENTIALS
) {
1057 memcpy(&cred
, CMSG_DATA(cmsg
), sizeof(struct ucred
));
1060 if (cmsg
->cmsg_level
== SOL_SOCKET
1061 && cmsg
->cmsg_type
== SCM_RIGHTS
) {
1062 dispose_fds((int *) CMSG_DATA(cmsg
),
1063 (cmsg
->cmsg_len
- CMSG_LEN(0))
1066 cmsg
= CMSG_NXTHDR(&msg
, cmsg
);
1070 #endif /* HAVE_UCRED */