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