1 /* Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
3 /** \file net.c Networking-related helper functions. */
7 #include <netinet/in.h>
10 #include <sys/types.h>
11 #include <sys/socket.h>
14 /* At least NetBSD needs these. */
22 #define AI_ADDRCONFIG 0
34 * Parse and validate IPv4 address/netmask string.
36 * \param cidr Address in CIDR notation
37 * \param addr Copy of the IPv4 address part of \a cidr
38 * \param addrlen Size of \a addr in bytes
39 * \param netmask Value of the netmask part in \a cidr or the
40 * default of 32 if not specified.
42 * \return Pointer to \a addr if successful, NULL on error.
45 char *parse_cidr(const char *cidr
,
46 char *addr
, ssize_t addrlen
,
50 char *c
= addr
, *end
= c
+ (addrlen
- 1);
54 if (cidr
== NULL
|| addrlen
< 1)
57 for (o
= cidr
; (*c
= *o
== '/'? '\0' : *o
); c
++, o
++)
62 if (para_atoi32(++o
, netmask
) < 0 ||
63 *netmask
< 0 || *netmask
> 0x20)
66 if (is_valid_ipv4_address(addr
))
75 * Match string as a candidate IPv4 address.
77 * \param address The string to match.
78 * \return True if \a address has "dot-quad" format.
80 static bool is_v4_dot_quad(const char *address
)
85 assert(para_regcomp(&r
, "^([0-9]+\\.){3}[0-9]+$",
86 REG_EXTENDED
| REG_NOSUB
) >= 0);
87 result
= regexec(&r
, address
, 0, NULL
, 0) == 0;
93 * Perform basic syntax checking on the host-part of an URL:
95 * - Since ':' is invalid in IPv4 addresses and DNS names, the
96 * presence of ':' causes interpretation as IPv6 address;
97 * - next the first-match-wins algorithm from RFC 3986 is applied;
98 * - else the string is considered as DNS name, to be resolved later.
100 * \param host The host string to check.
101 * \return True if \a host passes the syntax checks.
103 * \sa RFC 3986, 3.2.2; RFC 1123, 2.1; RFC 1034, 3.5.
105 static bool host_string_ok(const char *host
)
107 if (host
== NULL
|| *host
== '\0')
109 if (strchr(host
, ':') != NULL
)
110 return is_valid_ipv6_address(host
);
111 if (is_v4_dot_quad(host
))
112 return is_valid_ipv4_address(host
);
117 * Parse and validate URL string.
119 * The URL syntax is loosely based on RFC 3986, supporting one of
120 * - "["host"]"[:port] for native IPv6 addresses and
121 * - host[:port] for IPv4 hostnames and DNS names.
123 * Native IPv6 addresses must be enclosed in square brackets, since
124 * otherwise there is an ambiguity with the port separator `:'.
125 * The 'port' part is always considered to be a number; if absent,
126 * it is set to -1, to indicate that a default port is to be used.
128 * The following are valid examples:
136 * \param url The URL string to take apart.
137 * \param host To return the copied host part of \a url.
138 * \param hostlen The maximum length of \a host.
139 * \param port To return the port number (if any) of \a url.
141 * \return Pointer to \a host, or \p NULL if failed. If \p NULL is returned,
142 * \a host and \a port are undefined. If no port number was present in \a url,
143 * \a port is set to -1.
145 * \sa RFC 3986, 3.2.2/3.2.3.
147 char *parse_url(const char *url
,
148 char *host
, ssize_t hostlen
,
152 char *c
= host
, *end
= c
+ (hostlen
- 1);
156 if (o
== NULL
|| hostlen
< 1)
160 for (++o
; (*c
= *o
== ']' ? '\0' : *o
); c
++, o
++)
164 if (*o
++ != ']' || (*o
!= '\0' && *o
!= ':'))
167 for (; (*c
= *o
== ':'? '\0' : *o
); c
++, o
++) {
168 if (c
== end
&& o
[1])
174 if (para_atoi32(++o
, port
) < 0 || *port
< 0 || *port
> 0xffff)
176 if (host_string_ok(host
))
184 * Pretty-print a host/port pair.
186 * \param url NULL, or any string accepted by \ref parse_url().
187 * \param default_port Applies if url has no port.
189 * If the url argument is NULL, the function returns the string
190 * 0.0.0.0:default_port. Otherwise it calls \ref parse_url() to check the
191 * syntax of the input string given by url. On errors the string "?" is
192 * returned. Otherwise, if url contains a port, a copy of url is returned. If
193 * no port was supplied, a colon and the default port are appended to url.
195 * \return In all cases the returned string is a allocated with malloc(3) and
196 * has to be freed by the caller.
198 char *format_url(const char *url
, int default_port
)
200 char host
[MAX_HOSTLEN
];
204 return make_message("0.0.0.0:%d", default_port
);
205 if (!parse_url(url
, host
, sizeof(host
), &url_port
))
206 return make_message("?");
208 return make_message("%s:%d", url
, default_port
);
210 return para_strdup(url
);
214 * Stringify port number, resolve into service name where defined.
216 * \param port 2-byte port number, in host-byte-order.
217 * \param transport Transport protocol name (e.g. "udp", "tcp"), or NULL.
218 * \return Pointer to static result buffer.
220 * \sa getservent(3), services(5), nsswitch.conf(5).
222 const char *stringify_port(int port
, const char *transport
)
224 static char service
[NI_MAXSERV
];
226 if (port
< 0 || port
> 0xFFFF) {
227 snprintf(service
, sizeof(service
), "undefined (%d)", port
);
229 struct servent
*se
= getservbyport(htons(port
), transport
);
232 snprintf(service
, sizeof(service
), "%d", port
);
234 snprintf(service
, sizeof(service
), "%s", se
->s_name
);
240 * Determine the socket type for a given layer-4 protocol.
242 * \param l4type The symbolic name of the transport-layer protocol.
244 * \sa ip(7), socket(2).
246 static inline int sock_type(const unsigned l4type
)
249 case IPPROTO_UDP
: return SOCK_DGRAM
;
250 case IPPROTO_TCP
: return SOCK_STREAM
;
251 case IPPROTO_DCCP
: return SOCK_DCCP
;
253 return -1; /* not supported here */
257 * Pretty-print transport-layer name.
259 static const char *layer4_name(const unsigned l4type
)
262 case IPPROTO_UDP
: return "UDP";
263 case IPPROTO_TCP
: return "TCP";
264 case IPPROTO_DCCP
: return "DCCP";
266 return "UNKNOWN PROTOCOL";
270 * Flowopts: Transport-layer independent encapsulation of socket options.
272 * These collect individual socket options into a queue, which is disposed of
273 * directly after makesock(). The 'pre_conn_opt' structure is for internal use
274 * only and should not be visible elsewhere.
276 * \sa setsockopt(2), \ref makesock().
278 struct pre_conn_opt
{
279 int sock_level
; /**< Second argument to setsockopt() */
280 int sock_option
; /**< Third argument to setsockopt() */
281 char *opt_name
; /**< Stringified \a sock_option */
282 void *opt_val
; /**< Fourth argument to setsockopt() */
283 socklen_t opt_len
; /**< Fifth argument to setsockopt() */
285 struct list_head node
; /**< FIFO, as sockopt order matters. */
288 /** FIFO list of pre-connection socket options to be set */
290 struct list_head sockopts
;
294 * Allocate and initialize a flowopt queue.
296 * \return A new structure to be passed to \ref flowopt_add(). It is
297 * automatically deallocated in \ref makesock().
299 struct flowopts
*flowopt_new(void)
301 struct flowopts
*new = para_malloc(sizeof(*new));
303 INIT_LIST_HEAD(&new->sockopts
);
308 * Append new socket option to flowopt queue.
310 * \param fo The flowopt queue to append to.
311 * \param lev Level at which \a opt resides.
312 * \param opt New option to add.
313 * \param name Stringified name of \a opt.
314 * \param val The value to set \a opt to.
315 * \param len Length of \a val.
319 void flowopt_add(struct flowopts
*fo
, int lev
, int opt
,
320 const char *name
, const void *val
, int len
)
322 struct pre_conn_opt
*new = para_malloc(sizeof(*new));
324 new->sock_option
= opt
;
325 new->sock_level
= lev
;
326 new->opt_name
= para_strdup(name
);
332 new->opt_val
= para_malloc(len
);
334 memcpy(new->opt_val
, val
, len
);
337 list_add_tail(&new->node
, &fo
->sockopts
);
340 /** Set the entire bunch of pre-connection options at once. */
341 static void flowopt_setopts(int sockfd
, struct flowopts
*fo
)
343 struct pre_conn_opt
*pc
;
348 list_for_each_entry(pc
, &fo
->sockopts
, node
)
349 if (setsockopt(sockfd
, pc
->sock_level
, pc
->sock_option
,
350 pc
->opt_val
, pc
->opt_len
) < 0) {
351 PARA_EMERG_LOG("Can not set %s socket option: %s",
352 pc
->opt_name
, strerror(errno
));
358 * Deallocate all resources of a flowopts structure.
360 * \param fo A pointer as returned from flowopt_new().
362 * It's OK to pass \p NULL here in which case the function does nothing.
364 void flowopt_cleanup(struct flowopts
*fo
)
366 struct pre_conn_opt
*cur
, *next
;
371 list_for_each_entry_safe(cur
, next
, &fo
->sockopts
, node
) {
380 * Resolve an IPv4/IPv6 address.
382 * \param l4type The layer-4 type (\p IPPROTO_xxx).
383 * \param passive Whether \p AI_PASSIVE should be included as hint.
384 * \param host Remote or local hostname or IPv/6 address string.
385 * \param port_number Used to set the port in each returned address structure.
386 * \param result addrinfo structures are returned here.
388 * The interpretation of \a host depends on the value of \a passive. On a
389 * passive socket host is interpreted as an interface IPv4/6 address (can be
390 * left NULL). On an active socket, \a host is the peer DNS name or IPv4/6
391 * address to connect to.
395 * \sa getaddrinfo(3).
397 int lookup_address(unsigned l4type
, bool passive
, const char *host
,
398 int port_number
, struct addrinfo
**result
)
401 char port
[6]; /* port number has at most 5 digits */
402 struct addrinfo
*addr
= NULL
, hints
;
405 sprintf(port
, "%d", port_number
& 0xffff);
406 /* Set up address hint structure */
407 memset(&hints
, 0, sizeof(hints
));
408 hints
.ai_family
= AF_UNSPEC
;
409 hints
.ai_socktype
= sock_type(l4type
);
411 * getaddrinfo does not support SOCK_DCCP, so for the sake of lookup
412 * (and only then) pretend to be UDP.
414 if (l4type
== IPPROTO_DCCP
)
415 hints
.ai_socktype
= SOCK_DGRAM
;
416 /* only use addresses available on the host */
417 hints
.ai_flags
= AI_ADDRCONFIG
;
418 if (passive
&& host
== NULL
)
419 hints
.ai_flags
|= AI_PASSIVE
;
420 /* Obtain local/remote address information */
421 ret
= getaddrinfo(host
, port
, &hints
, &addr
);
423 PARA_ERROR_LOG("can not resolve %s address %s#%s: %s\n",
425 host
? host
: (passive
? "[loopback]" : "[localhost]"),
426 port
, gai_strerror(ret
));
427 return -E_ADDRESS_LOOKUP
;
434 * Create an active or passive socket.
436 * \param l4type \p IPPROTO_TCP, \p IPPROTO_UDP, or \p IPPROTO_DCCP.
437 * \param passive Whether to call bind(2) or connect(2).
438 * \param ai Address information as obtained from \ref lookup_address().
439 * \param fo Socket options to be set before making the connection.
441 * bind(2) is called on passive sockets, and connect(2) on active sockets. The
442 * algorithm tries all possible address combinations until it succeeds. If \a
443 * fo is supplied, options are set but cleanup must be performed in the caller.
445 * \return File descriptor on success, \p E_MAKESOCK on errors.
447 * \sa \ref lookup_address(), \ref makesock(), ip(7), ipv6(7), bind(2),
450 int makesock_addrinfo(unsigned l4type
, bool passive
, struct addrinfo
*ai
,
453 int ret
= -E_MAKESOCK
, on
= 1;
455 for (; ai
; ai
= ai
->ai_next
) {
457 ret
= socket(ai
->ai_family
, sock_type(l4type
), l4type
);
459 PARA_NOTICE_LOG("socket(): %s\n", strerror(errno
));
463 flowopt_setopts(fd
, fo
);
465 if (connect(fd
, ai
->ai_addr
, ai
->ai_addrlen
) < 0) {
466 PARA_NOTICE_LOG("connect(): %s\n",
474 * Reuse the address on passive sockets to avoid failure on
475 * restart (protocols using listen()) and when creating
476 * multiple listener instances (UDP multicast).
478 if (setsockopt(fd
, SOL_SOCKET
, SO_REUSEADDR
, &on
,
480 PARA_NOTICE_LOG("setsockopt(): %s\n", strerror(errno
));
484 if (bind(fd
, ai
->ai_addr
, ai
->ai_addrlen
) < 0) {
485 PARA_NOTICE_LOG("bind(): %s\n", strerror(errno
));
495 * Resolve IPv4/IPv6 address and create a ready-to-use active or passive socket.
497 * \param l4type The layer-4 type (\p IPPROTO_xxx).
498 * \param passive Whether this is a passive or active socket.
499 * \param host Passed to \ref lookup_address().
500 * \param port_number Passed to \ref lookup_address().
501 * \param fo Passed to \ref makesock_addrinfo().
503 * This creates a ready-made IPv4/v6 socket structure after looking up the
504 * necessary parameters. The function first calls \ref lookup_address() and
505 * passes the address information to makesock_addrinfo() to create and
506 * initialize the socket.
508 * \return The newly created file descriptor on success, a negative error code
511 * \sa \ref lookup_address(), \ref makesock_addrinfo().
513 int makesock(unsigned l4type
, bool passive
, const char *host
, uint16_t port_number
,
517 int ret
= lookup_address(l4type
, passive
, host
, port_number
, &ai
);
520 ret
= makesock_addrinfo(l4type
, passive
, ai
, fo
);
524 PARA_ERROR_LOG("can not create %s socket %s#%d.\n",
525 layer4_name(l4type
), host
? host
: (passive
?
526 "[loopback]" : "[localhost]"), port_number
);
532 * Create a passive / listening socket.
534 * \param l4type The transport-layer type (\p IPPROTO_xxx).
535 * \param addr Passed to \ref parse_url() if not NULL.
536 * \param port Ignored if addr contains a port number.
538 * \return Positive integer (socket descriptor) on success, negative value
541 * \sa \ref makesock(), ip(7), ipv6(7), bind(2), listen(2).
543 int para_listen(unsigned l4type
, const char *addr
, uint16_t port
)
545 char host
[MAX_HOSTLEN
];
546 int ret
, fd
, addr_port
;
549 if (!parse_url(addr
, host
, sizeof(host
), &addr_port
))
550 return -ERRNO_TO_PARA_ERROR(EINVAL
);
555 fd
= makesock(l4type
, true /* passive */, addr
, port
,
556 NULL
/* no flowopts */);
558 ret
= listen(fd
, BACKLOG
);
562 return -ERRNO_TO_PARA_ERROR(ret
);
564 PARA_INFO_LOG("listening on %s port %u, fd %d\n",
565 layer4_name(l4type
), port
, fd
);
571 * Create a socket which listens on all network addresses.
573 * \param l4type See \ref para_listen().
574 * \param port See \ref para_listen().
576 * This is a simple wrapper for \ref para_listen() which passes a NULL pointer
577 * as the address information.
579 * \return See \ref para_listen().
581 int para_listen_simple(unsigned l4type
, uint16_t port
)
583 return para_listen(l4type
, NULL
, port
);
587 * Determine IPv4/v6 socket address length.
588 * \param sa Container of IPv4 or IPv6 address.
589 * \return Address-family dependent address length.
591 static socklen_t
salen(const struct sockaddr
*sa
)
593 assert(sa
->sa_family
== AF_INET
|| sa
->sa_family
== AF_INET6
);
595 return sa
->sa_family
== AF_INET6
596 ? sizeof(struct sockaddr_in6
)
597 : sizeof(struct sockaddr_in
);
600 /** True if @ss holds a v6-mapped-v4 address (RFC 4291, 2.5.5.2) */
601 static bool SS_IS_ADDR_V4MAPPED(const struct sockaddr_storage
*ss
)
603 const struct sockaddr_in6
*ia6
= (const struct sockaddr_in6
*)ss
;
605 return ss
->ss_family
== AF_INET6
&& IN6_IS_ADDR_V4MAPPED(&ia6
->sin6_addr
);
609 * Process IPv4/v6 address, turn v6-mapped-v4 address into normal IPv4 address.
610 * \param ss Container of IPv4/6 address.
611 * \return Pointer to normalized address (may be static storage).
615 static const struct sockaddr
*
616 normalize_ip_address(const struct sockaddr_storage
*ss
)
618 assert(ss
->ss_family
== AF_INET
|| ss
->ss_family
== AF_INET6
);
620 if (SS_IS_ADDR_V4MAPPED(ss
)) {
621 const struct sockaddr_in6
*ia6
= (const struct sockaddr_in6
*)ss
;
622 static struct sockaddr_in ia
;
624 ia
.sin_family
= AF_INET
;
625 ia
.sin_port
= ia6
->sin6_port
;
626 memcpy(&ia
.sin_addr
.s_addr
, &(ia6
->sin6_addr
.s6_addr
[12]), 4);
627 return (const struct sockaddr
*)&ia
;
629 return (const struct sockaddr
*)ss
;
633 * Generic/fallback MTU values
635 * These are taken from RFC 1122, RFC 2460, and RFC 5405.
636 * - RFC 1122, 3.3.3 defines EMTU_S ("Effective MTU for sending") and recommends
637 * to use an EMTU_S size of of 576 bytes if the IPv4 path MTU is unknown;
638 * - RFC 2460, 5. requires a minimum IPv6 MTU of 1280 bytes;
639 * - RFC 5405, 3.2 recommends that if path MTU discovery is not done,
640 * UDP senders should use the respective minimum values of EMTU_S.
642 static inline int generic_mtu(const int af_type
)
644 return af_type
== AF_INET6
? 1280 : 576;
647 /** Crude approximation of IP header overhead - neglecting options. */
648 static inline int estimated_header_overhead(const int af_type
)
650 return af_type
== AF_INET6
? 40 : 20;
654 * Get the maximum transport-layer message size (MMS_S).
656 * \param sockfd The socket file descriptor.
658 * The socket must be connected. See RFC 1122, 3.3.3. If the protocol family
659 * could not be determined, \p AF_INET is assumed.
661 * \return The maximum message size of the address family type.
663 int generic_max_transport_msg_size(int sockfd
)
665 struct sockaddr_storage ss
= {.ss_family
= 0};
666 socklen_t sslen
= sizeof(ss
);
667 int af_type
= AF_INET
;
669 if (getpeername(sockfd
, (struct sockaddr
*)&ss
, &sslen
) < 0) {
670 PARA_ERROR_LOG("can not determine remote address type: %s\n",
672 } else if (!SS_IS_ADDR_V4MAPPED(&ss
)) {
673 af_type
= ss
.ss_family
;
675 return generic_mtu(af_type
) - estimated_header_overhead(af_type
);
679 * Look up the remote side of a connected socket structure.
681 * \param fd The socket descriptor of the connected socket.
683 * \return A static character string identifying hostname and port of the
684 * chosen side in numeric host:port format.
686 * \sa getsockname(2), getpeername(2), \ref parse_url(), getnameinfo(3),
687 * services(5), nsswitch.conf(5).
689 char *remote_name(int fd
)
691 struct sockaddr_storage ss
= {.ss_family
= 0};
692 const struct sockaddr
*sa
;
693 socklen_t sslen
= sizeof(ss
);
694 char hbuf
[NI_MAXHOST
], sbuf
[NI_MAXSERV
];
695 static char output
[sizeof(hbuf
) + sizeof(sbuf
) + 4];
698 if (getpeername(fd
, (struct sockaddr
*)&ss
, &sslen
) < 0) {
699 PARA_ERROR_LOG("can not determine address from fd %d: %s\n",
700 fd
, strerror(errno
));
701 snprintf(output
, sizeof(output
), "(unknown)");
704 sa
= normalize_ip_address(&ss
);
705 ret
= getnameinfo(sa
, salen(sa
), hbuf
, sizeof(hbuf
), sbuf
,
706 sizeof(sbuf
), NI_NUMERICHOST
| NI_NUMERICSERV
);
708 PARA_WARNING_LOG("hostname lookup error (%s).\n",
710 snprintf(output
, sizeof(output
), "(lookup error)");
711 } else if (sa
->sa_family
== AF_INET6
)
712 snprintf(output
, sizeof(output
), "[%s]:%s", hbuf
, sbuf
);
714 snprintf(output
, sizeof(output
), "%s:%s", hbuf
, sbuf
);
719 * Extract IPv4 or IPv6-mapped-IPv4 address from sockaddr_storage.
721 * \param ss Container of IPv4/6 address.
722 * \param ia Extracted IPv4 address (different from 0) or 0 if unsuccessful.
726 void extract_v4_addr(const struct sockaddr_storage
*ss
, struct in_addr
*ia
)
728 const struct sockaddr
*sa
= normalize_ip_address(ss
);
730 memset(ia
, 0, sizeof(*ia
));
731 if (sa
->sa_family
== AF_INET
)
732 *ia
= ((struct sockaddr_in
*)sa
)->sin_addr
;
736 * Compare the address part of IPv4/6 addresses.
738 * \param sa1 First address.
739 * \param sa2 Second address.
741 * \return True iff the IP address of \a sa1 and \a sa2 match.
743 bool sockaddr_equal(const struct sockaddr
*sa1
, const struct sockaddr
*sa2
)
747 if (sa1
->sa_family
!= sa2
->sa_family
)
749 if (sa1
->sa_family
== AF_INET
) {
750 struct sockaddr_in
*a1
= (typeof(a1
))sa1
,
751 *a2
= (typeof (a2
))sa2
;
752 return a1
->sin_addr
.s_addr
== a2
->sin_addr
.s_addr
;
753 } else if (sa1
->sa_family
== AF_INET6
) {
754 struct sockaddr_in6
*a1
= (typeof(a1
))sa1
,
755 *a2
= (typeof (a2
))sa2
;
756 return !memcmp(a1
, a2
, sizeof(*a1
));
762 * Receive data from a file descriptor.
764 * \param fd The file descriptor.
765 * \param buf The buffer to write the data to.
766 * \param size The size of \a buf.
768 * Receive at most \a size bytes from file descriptor \a fd.
770 * \return The number of bytes received on success, negative on errors, zero if
771 * the peer has performed an orderly shutdown.
775 __must_check
int recv_bin_buffer(int fd
, char *buf
, size_t size
)
779 n
= recv(fd
, buf
, size
, 0);
781 return -ERRNO_TO_PARA_ERROR(errno
);
786 * Receive and write terminating NULL byte.
788 * \param fd The file descriptor.
789 * \param buf The buffer to write the data to.
790 * \param size The size of \a buf.
792 * Read at most \a size - 1 bytes from file descriptor \a fd and
793 * write a NULL byte at the end of the received data.
795 * \return The return value of the underlying call to \a recv_bin_buffer().
797 * \sa \ref recv_bin_buffer()
799 int recv_buffer(int fd
, char *buf
, size_t size
)
804 n
= recv_bin_buffer(fd
, buf
, size
- 1);
813 * Wrapper around the accept system call.
815 * \param fd The listening socket.
816 * \param rfds An optional fd_set pointer.
817 * \param addr Structure which is filled in with the address of the peer socket.
818 * \param size Should contain the size of the structure pointed to by \a addr.
819 * \param new_fd Result pointer.
821 * Accept incoming connections on \a addr, retry if interrupted. If \a rfds is
822 * not \p NULL, return 0 if \a fd is not set in \a rfds without calling accept().
824 * \return Negative on errors, zero if no connections are present to be accepted,
829 int para_accept(int fd
, fd_set
*rfds
, void *addr
, socklen_t size
, int *new_fd
)
833 if (rfds
&& !FD_ISSET(fd
, rfds
))
836 ret
= accept(fd
, (struct sockaddr
*) addr
, &size
);
837 while (ret
< 0 && errno
== EINTR
);
843 if (errno
== EAGAIN
|| errno
== EWOULDBLOCK
)
845 return -ERRNO_TO_PARA_ERROR(errno
);
849 * Probe the list of DCCP CCIDs configured on this host.
850 * \param ccid_array Pointer to return statically allocated array in.
851 * \return Number of elements returned in \a ccid_array or error.
853 * NB: This feature is only available on Linux > 2.6.30; on older kernels
854 * ENOPROTOOPT ("Protocol not available") will be returned.
856 int dccp_available_ccids(uint8_t **ccid_array
)
858 static uint8_t ccids
[DCCP_MAX_HOST_CCIDS
];
859 socklen_t nccids
= sizeof(ccids
);
862 ret
= fd
= makesock(IPPROTO_DCCP
, 1, NULL
, 0, NULL
);
866 if (getsockopt(fd
, SOL_DCCP
, DCCP_SOCKOPT_AVAILABLE_CCIDS
,
867 ccids
, &nccids
) < 0) {
870 PARA_ERROR_LOG("No DCCP_SOCKOPT_AVAILABLE_CCIDS: %s\n",
872 return -ERRNO_TO_PARA_ERROR(ret
);
881 * Prepare a structure for AF_UNIX socket addresses.
883 * This just copies name to the sun_path component of u, prepending a zero byte
884 * if abstract sockets are supported.
886 * The first call to this function tries to bind a socket to the abstract name
887 * space. The result of this test is stored in a static variable. Subsequent
888 * calls read this variable and create abstract sockets on systems that support
891 static int init_unix_addr(struct sockaddr_un
*u
, const char *name
)
893 static int use_abstract
;
895 if (strlen(name
) + 1 >= UNIX_PATH_MAX
)
896 return -E_NAME_TOO_LONG
;
897 memset(u
->sun_path
, 0, UNIX_PATH_MAX
);
898 u
->sun_family
= PF_UNIX
;
899 if (use_abstract
== 0) { /* executed only once */
900 int fd
= socket(PF_UNIX
, SOCK_STREAM
, 0);
901 memcpy(u
->sun_path
, "\0x\0", 3);
902 if (bind(fd
, (struct sockaddr
*)u
, sizeof(*u
)) == 0)
903 use_abstract
= 1; /* yes */
905 use_abstract
= -1; /* no */
907 PARA_NOTICE_LOG("%susing abstract socket namespace\n",
908 use_abstract
== 1? "" : "not ");
910 strcpy(u
->sun_path
+ (use_abstract
== 1? 1 : 0), name
);
915 * Create a socket for local communication and listen on it.
917 * \param name The socket pathname.
919 * This function creates a passive local socket for sequenced, reliable,
920 * two-way, connection-based byte streams. The socket file descriptor is set to
921 * nonblocking mode and listen(2) is called to prepare the socket for
922 * accepting incoming connection requests.
924 * \return The file descriptor on success, negative error code on failure.
926 * \sa socket(2), \sa bind(2), \sa chmod(2), listen(2), unix(7).
928 int create_local_socket(const char *name
)
930 struct sockaddr_un unix_addr
;
933 ret
= init_unix_addr(&unix_addr
, name
);
936 ret
= socket(PF_UNIX
, SOCK_STREAM
, 0);
938 return -ERRNO_TO_PARA_ERROR(errno
);
940 ret
= mark_fd_nonblocking(fd
);
943 ret
= bind(fd
, (struct sockaddr
*)&unix_addr
, sizeof(unix_addr
));
945 ret
= -ERRNO_TO_PARA_ERROR(errno
);
948 if (unix_addr
.sun_path
[0] != 0) { /* pathname socket */
949 mode_t mode
= S_IRUSR
| S_IWUSR
| S_IRGRP
| S_IWGRP
952 if (chmod(name
, mode
) < 0)
955 if (listen(fd
, 5) < 0) {
956 ret
= -ERRNO_TO_PARA_ERROR(errno
);
966 * Prepare, create, and connect to a Unix domain socket for local communication.
968 * \param name The socket pathname.
970 * This function creates a local socket for sequenced, reliable, two-way,
971 * connection-based byte streams.
973 * \return The file descriptor of the connected socket on success, negative on
976 * \sa \ref create_local_socket(), unix(7), connect(2).
978 int connect_local_socket(const char *name
)
980 struct sockaddr_un unix_addr
;
983 PARA_DEBUG_LOG("connecting to %s\n", name
);
984 fd
= socket(PF_UNIX
, SOCK_STREAM
, 0);
986 return -ERRNO_TO_PARA_ERROR(errno
);
987 ret
= init_unix_addr(&unix_addr
, name
);
990 if (connect(fd
, (struct sockaddr
*)&unix_addr
, sizeof(unix_addr
)) != -1)
992 ret
= -ERRNO_TO_PARA_ERROR(errno
);
999 ssize_t
send_cred_buffer(int sock
, char *buf
)
1001 return write_buffer(sock
, buf
);
1003 int recv_cred_buffer(int fd
, char *buf
, size_t size
)
1005 return recv_buffer(fd
, buf
, size
) > 0? 1 : -E_RECVMSG
;
1007 #else /* HAVE_UCRED */
1010 * Send a buffer and the credentials of the current process to a socket.
1012 * \param sock The file descriptor of the sending socket.
1013 * \param buf The zero-terminated buffer to send.
1015 * \return On success, this call returns the number of bytes sent. On errors,
1016 * \p -E_SENDMSG is returned.
1018 * \sa \ref recv_cred_buffer, sendmsg(2), socket(7), unix(7).
1020 ssize_t
send_cred_buffer(int sock
, char *buf
)
1022 char control
[sizeof(struct cmsghdr
) + sizeof(struct ucred
)];
1024 struct cmsghdr
*cmsg
;
1025 static struct iovec iov
;
1031 iov
.iov_len
= strlen(buf
);
1035 /* compose the message */
1036 memset(&msg
, 0, sizeof(msg
));
1039 msg
.msg_control
= control
;
1040 msg
.msg_controllen
= sizeof(control
);
1041 /* attach the ucred struct */
1042 cmsg
= CMSG_FIRSTHDR(&msg
);
1043 cmsg
->cmsg_level
= SOL_SOCKET
;
1044 cmsg
->cmsg_type
= SCM_CREDENTIALS
;
1045 cmsg
->cmsg_len
= CMSG_LEN(sizeof(struct ucred
));
1046 *(struct ucred
*)CMSG_DATA(cmsg
) = c
;
1047 msg
.msg_controllen
= cmsg
->cmsg_len
;
1048 ret
= sendmsg(sock
, &msg
, 0);
1054 static void dispose_fds(int *fds
, unsigned num
)
1058 for (i
= 0; i
< num
; i
++)
1063 * Receive a buffer and the Unix credentials of the sending process.
1065 * \param fd The file descriptor of the receiving socket.
1066 * \param buf The buffer to store the received message.
1067 * \param size The length of \a buf in bytes.
1069 * \return Negative on errors, the user id of the sending process on success.
1071 * \sa \ref send_cred_buffer and the references given there.
1073 int recv_cred_buffer(int fd
, char *buf
, size_t size
)
1075 char control
[255] __a_aligned(8);
1077 struct cmsghdr
*cmsg
;
1083 setsockopt(fd
, SOL_SOCKET
, SO_PASSCRED
, &yes
, sizeof(int));
1084 memset(&msg
, 0, sizeof(msg
));
1085 memset(buf
, 0, size
);
1090 msg
.msg_control
= control
;
1091 msg
.msg_controllen
= sizeof(control
);
1092 if (recvmsg(fd
, &msg
, 0) < 0)
1094 result
= -E_SCM_CREDENTIALS
;
1095 cmsg
= CMSG_FIRSTHDR(&msg
);
1097 if (cmsg
->cmsg_level
== SOL_SOCKET
&& cmsg
->cmsg_type
1098 == SCM_CREDENTIALS
) {
1099 memcpy(&cred
, CMSG_DATA(cmsg
), sizeof(struct ucred
));
1102 if (cmsg
->cmsg_level
== SOL_SOCKET
1103 && cmsg
->cmsg_type
== SCM_RIGHTS
) {
1104 dispose_fds((int *)CMSG_DATA(cmsg
),
1105 (cmsg
->cmsg_len
- CMSG_LEN(0))
1108 cmsg
= CMSG_NXTHDR(&msg
, cmsg
);
1112 #endif /* HAVE_UCRED */