2 This file is part of systemd.
4 Copyright 2010 Lennart Poettering
6 systemd is free software; you can redistribute it and/or modify it
7 under the terms of the GNU Lesser General Public License as published by
8 the Free Software Foundation; either version 2.1 of the License, or
9 (at your option) any later version.
11 systemd is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public License
17 along with systemd; If not, see <http://www.gnu.org/licenses/>.
20 #include <arpa/inet.h>
25 #include <netinet/ip.h>
34 #include "alloc-util.h"
37 #include "format-util.h"
41 #include "parse-util.h"
42 #include "path-util.h"
43 #include "socket-util.h"
44 #include "string-table.h"
45 #include "string-util.h"
47 #include "user-util.h"
52 # define IDN_FLAGS (NI_IDN|NI_IDN_USE_STD3_ASCII_RULES)
57 int socket_address_parse(SocketAddress
*a
, const char *s
) {
66 a
->type
= SOCK_STREAM
;
69 /* IPv6 in [x:.....:z]:p notation */
75 n
= strndupa(s
+1, e
-s
-1);
78 if (inet_pton(AF_INET6
, n
, &a
->sockaddr
.in6
.sin6_addr
) <= 0)
79 return errno
> 0 ? -errno
: -EINVAL
;
90 if (u
<= 0 || u
> 0xFFFF)
93 a
->sockaddr
.in6
.sin6_family
= AF_INET6
;
94 a
->sockaddr
.in6
.sin6_port
= htobe16((uint16_t)u
);
95 a
->size
= sizeof(struct sockaddr_in6
);
97 } else if (*s
== '/') {
103 if (l
>= sizeof(a
->sockaddr
.un
.sun_path
))
106 a
->sockaddr
.un
.sun_family
= AF_UNIX
;
107 memcpy(a
->sockaddr
.un
.sun_path
, s
, l
);
108 a
->size
= offsetof(struct sockaddr_un
, sun_path
) + l
+ 1;
110 } else if (*s
== '@') {
111 /* Abstract AF_UNIX socket */
115 if (l
>= sizeof(a
->sockaddr
.un
.sun_path
) - 1)
118 a
->sockaddr
.un
.sun_family
= AF_UNIX
;
119 memcpy(a
->sockaddr
.un
.sun_path
+1, s
+1, l
);
120 a
->size
= offsetof(struct sockaddr_un
, sun_path
) + 1 + l
;
122 } else if (startswith(s
, "vsock:")) {
123 /* AF_VSOCK socket in vsock:cid:port notation */
124 const char *cid_start
= s
+ strlen("vsock:");
126 e
= strchr(cid_start
, ':');
130 r
= safe_atou(e
+1, &u
);
134 n
= strndupa(cid_start
, e
- cid_start
);
136 r
= safe_atou(n
, &a
->sockaddr
.vm
.svm_cid
);
140 a
->sockaddr
.vm
.svm_cid
= VMADDR_CID_ANY
;
142 a
->sockaddr
.vm
.svm_family
= AF_VSOCK
;
143 a
->sockaddr
.vm
.svm_port
= u
;
144 a
->size
= sizeof(struct sockaddr_vm
);
149 r
= safe_atou(e
+1, &u
);
153 if (u
<= 0 || u
> 0xFFFF)
156 n
= strndupa(s
, e
-s
);
158 /* IPv4 in w.x.y.z:p notation? */
159 r
= inet_pton(AF_INET
, n
, &a
->sockaddr
.in
.sin_addr
);
164 /* Gotcha, it's a traditional IPv4 address */
165 a
->sockaddr
.in
.sin_family
= AF_INET
;
166 a
->sockaddr
.in
.sin_port
= htobe16((uint16_t)u
);
167 a
->size
= sizeof(struct sockaddr_in
);
171 if (strlen(n
) > IF_NAMESIZE
-1)
174 /* Uh, our last resort, an interface name */
175 idx
= if_nametoindex(n
);
179 a
->sockaddr
.in6
.sin6_family
= AF_INET6
;
180 a
->sockaddr
.in6
.sin6_port
= htobe16((uint16_t)u
);
181 a
->sockaddr
.in6
.sin6_scope_id
= idx
;
182 a
->sockaddr
.in6
.sin6_addr
= in6addr_any
;
183 a
->size
= sizeof(struct sockaddr_in6
);
188 r
= safe_atou(s
, &u
);
192 if (u
<= 0 || u
> 0xFFFF)
195 if (socket_ipv6_is_supported()) {
196 a
->sockaddr
.in6
.sin6_family
= AF_INET6
;
197 a
->sockaddr
.in6
.sin6_port
= htobe16((uint16_t)u
);
198 a
->sockaddr
.in6
.sin6_addr
= in6addr_any
;
199 a
->size
= sizeof(struct sockaddr_in6
);
201 a
->sockaddr
.in
.sin_family
= AF_INET
;
202 a
->sockaddr
.in
.sin_port
= htobe16((uint16_t)u
);
203 a
->sockaddr
.in
.sin_addr
.s_addr
= INADDR_ANY
;
204 a
->size
= sizeof(struct sockaddr_in
);
212 int socket_address_parse_and_warn(SocketAddress
*a
, const char *s
) {
216 /* Similar to socket_address_parse() but warns for IPv6 sockets when we don't support them. */
218 r
= socket_address_parse(&b
, s
);
222 if (!socket_ipv6_is_supported() && b
.sockaddr
.sa
.sa_family
== AF_INET6
) {
223 log_warning("Binding to IPv6 address not available since kernel does not support IPv6.");
224 return -EAFNOSUPPORT
;
231 int socket_address_parse_netlink(SocketAddress
*a
, const char *s
) {
234 _cleanup_free_
char *sfamily
= NULL
;
242 if (sscanf(s
, "%ms %u", &sfamily
, &group
) < 1)
243 return errno
> 0 ? -errno
: -EINVAL
;
245 family
= netlink_family_from_string(sfamily
);
249 a
->sockaddr
.nl
.nl_family
= AF_NETLINK
;
250 a
->sockaddr
.nl
.nl_groups
= group
;
253 a
->size
= sizeof(struct sockaddr_nl
);
254 a
->protocol
= family
;
259 int socket_address_verify(const SocketAddress
*a
) {
262 switch (socket_address_family(a
)) {
265 if (a
->size
!= sizeof(struct sockaddr_in
))
268 if (a
->sockaddr
.in
.sin_port
== 0)
271 if (!IN_SET(a
->type
, SOCK_STREAM
, SOCK_DGRAM
))
277 if (a
->size
!= sizeof(struct sockaddr_in6
))
280 if (a
->sockaddr
.in6
.sin6_port
== 0)
283 if (!IN_SET(a
->type
, SOCK_STREAM
, SOCK_DGRAM
))
289 if (a
->size
< offsetof(struct sockaddr_un
, sun_path
))
292 if (a
->size
> offsetof(struct sockaddr_un
, sun_path
)) {
294 if (a
->sockaddr
.un
.sun_path
[0] != 0) {
298 e
= memchr(a
->sockaddr
.un
.sun_path
, 0, sizeof(a
->sockaddr
.un
.sun_path
));
302 if (a
->size
!= offsetof(struct sockaddr_un
, sun_path
) + (e
- a
->sockaddr
.un
.sun_path
) + 1)
307 if (!IN_SET(a
->type
, SOCK_STREAM
, SOCK_DGRAM
, SOCK_SEQPACKET
))
314 if (a
->size
!= sizeof(struct sockaddr_nl
))
317 if (!IN_SET(a
->type
, SOCK_RAW
, SOCK_DGRAM
))
323 if (a
->size
!= sizeof(struct sockaddr_vm
))
326 if (!IN_SET(a
->type
, SOCK_STREAM
, SOCK_DGRAM
))
332 return -EAFNOSUPPORT
;
336 int socket_address_print(const SocketAddress
*a
, char **ret
) {
342 r
= socket_address_verify(a
);
346 if (socket_address_family(a
) == AF_NETLINK
) {
347 _cleanup_free_
char *sfamily
= NULL
;
349 r
= netlink_family_to_string_alloc(a
->protocol
, &sfamily
);
353 r
= asprintf(ret
, "%s %u", sfamily
, a
->sockaddr
.nl
.nl_groups
);
360 return sockaddr_pretty(&a
->sockaddr
.sa
, a
->size
, false, true, ret
);
363 bool socket_address_can_accept(const SocketAddress
*a
) {
367 IN_SET(a
->type
, SOCK_STREAM
, SOCK_SEQPACKET
);
370 bool socket_address_equal(const SocketAddress
*a
, const SocketAddress
*b
) {
374 /* Invalid addresses are unequal to all */
375 if (socket_address_verify(a
) < 0 ||
376 socket_address_verify(b
) < 0)
379 if (a
->type
!= b
->type
)
382 if (socket_address_family(a
) != socket_address_family(b
))
385 switch (socket_address_family(a
)) {
388 if (a
->sockaddr
.in
.sin_addr
.s_addr
!= b
->sockaddr
.in
.sin_addr
.s_addr
)
391 if (a
->sockaddr
.in
.sin_port
!= b
->sockaddr
.in
.sin_port
)
397 if (memcmp(&a
->sockaddr
.in6
.sin6_addr
, &b
->sockaddr
.in6
.sin6_addr
, sizeof(a
->sockaddr
.in6
.sin6_addr
)) != 0)
400 if (a
->sockaddr
.in6
.sin6_port
!= b
->sockaddr
.in6
.sin6_port
)
406 if (a
->size
<= offsetof(struct sockaddr_un
, sun_path
) ||
407 b
->size
<= offsetof(struct sockaddr_un
, sun_path
))
410 if ((a
->sockaddr
.un
.sun_path
[0] == 0) != (b
->sockaddr
.un
.sun_path
[0] == 0))
413 if (a
->sockaddr
.un
.sun_path
[0]) {
414 if (!path_equal_or_files_same(a
->sockaddr
.un
.sun_path
, b
->sockaddr
.un
.sun_path
, 0))
417 if (a
->size
!= b
->size
)
420 if (memcmp(a
->sockaddr
.un
.sun_path
, b
->sockaddr
.un
.sun_path
, a
->size
) != 0)
427 if (a
->protocol
!= b
->protocol
)
430 if (a
->sockaddr
.nl
.nl_groups
!= b
->sockaddr
.nl
.nl_groups
)
436 if (a
->sockaddr
.vm
.svm_cid
!= b
->sockaddr
.vm
.svm_cid
)
439 if (a
->sockaddr
.vm
.svm_port
!= b
->sockaddr
.vm
.svm_port
)
445 /* Cannot compare, so we assume the addresses are different */
452 bool socket_address_is(const SocketAddress
*a
, const char *s
, int type
) {
453 struct SocketAddress b
;
458 if (socket_address_parse(&b
, s
) < 0)
463 return socket_address_equal(a
, &b
);
466 bool socket_address_is_netlink(const SocketAddress
*a
, const char *s
) {
467 struct SocketAddress b
;
472 if (socket_address_parse_netlink(&b
, s
) < 0)
475 return socket_address_equal(a
, &b
);
478 const char* socket_address_get_path(const SocketAddress
*a
) {
481 if (socket_address_family(a
) != AF_UNIX
)
484 if (a
->sockaddr
.un
.sun_path
[0] == 0)
487 return a
->sockaddr
.un
.sun_path
;
490 bool socket_ipv6_is_supported(void) {
491 if (access("/proc/net/if_inet6", F_OK
) != 0)
497 bool socket_address_matches_fd(const SocketAddress
*a
, int fd
) {
504 b
.size
= sizeof(b
.sockaddr
);
505 if (getsockname(fd
, &b
.sockaddr
.sa
, &b
.size
) < 0)
508 if (b
.sockaddr
.sa
.sa_family
!= a
->sockaddr
.sa
.sa_family
)
511 solen
= sizeof(b
.type
);
512 if (getsockopt(fd
, SOL_SOCKET
, SO_TYPE
, &b
.type
, &solen
) < 0)
515 if (b
.type
!= a
->type
)
518 if (a
->protocol
!= 0) {
519 solen
= sizeof(b
.protocol
);
520 if (getsockopt(fd
, SOL_SOCKET
, SO_PROTOCOL
, &b
.protocol
, &solen
) < 0)
523 if (b
.protocol
!= a
->protocol
)
527 return socket_address_equal(a
, &b
);
530 int sockaddr_port(const struct sockaddr
*_sa
, unsigned *port
) {
531 union sockaddr_union
*sa
= (union sockaddr_union
*) _sa
;
535 switch (sa
->sa
.sa_family
) {
537 *port
= be16toh(sa
->in
.sin_port
);
541 *port
= be16toh(sa
->in6
.sin6_port
);
545 *port
= sa
->vm
.svm_port
;
549 return -EAFNOSUPPORT
;
553 int sockaddr_pretty(const struct sockaddr
*_sa
, socklen_t salen
, bool translate_ipv6
, bool include_port
, char **ret
) {
554 union sockaddr_union
*sa
= (union sockaddr_union
*) _sa
;
559 assert(salen
>= sizeof(sa
->sa
.sa_family
));
561 switch (sa
->sa
.sa_family
) {
566 a
= be32toh(sa
->in
.sin_addr
.s_addr
);
571 a
>> 24, (a
>> 16) & 0xFF, (a
>> 8) & 0xFF, a
& 0xFF,
572 be16toh(sa
->in
.sin_port
));
576 a
>> 24, (a
>> 16) & 0xFF, (a
>> 8) & 0xFF, a
& 0xFF);
583 static const unsigned char ipv4_prefix
[] = {
584 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF
587 if (translate_ipv6
&&
588 memcmp(&sa
->in6
.sin6_addr
, ipv4_prefix
, sizeof(ipv4_prefix
)) == 0) {
589 const uint8_t *a
= sa
->in6
.sin6_addr
.s6_addr
+12;
593 a
[0], a
[1], a
[2], a
[3],
594 be16toh(sa
->in6
.sin6_port
));
598 a
[0], a
[1], a
[2], a
[3]);
602 char a
[INET6_ADDRSTRLEN
];
604 inet_ntop(AF_INET6
, &sa
->in6
.sin6_addr
, a
, sizeof(a
));
610 be16toh(sa
->in6
.sin6_port
));
624 if (salen
<= offsetof(struct sockaddr_un
, sun_path
)) {
625 p
= strdup("<unnamed>");
629 } else if (sa
->un
.sun_path
[0] == 0) {
632 /* FIXME: We assume we can print the
633 * socket path here and that it hasn't
634 * more than one NUL byte. That is
635 * actually an invalid assumption */
637 p
= new(char, sizeof(sa
->un
.sun_path
)+1);
642 memcpy(p
+1, sa
->un
.sun_path
+1, sizeof(sa
->un
.sun_path
)-1);
643 p
[sizeof(sa
->un
.sun_path
)] = 0;
646 p
= strndup(sa
->un
.sun_path
, sizeof(sa
->un
.sun_path
));
660 r
= asprintf(&p
, "vsock:%u", sa
->vm
.svm_cid
);
674 int getpeername_pretty(int fd
, bool include_port
, char **ret
) {
675 union sockaddr_union sa
;
676 socklen_t salen
= sizeof(sa
);
682 if (getpeername(fd
, &sa
.sa
, &salen
) < 0)
685 if (sa
.sa
.sa_family
== AF_UNIX
) {
686 struct ucred ucred
= {};
688 /* UNIX connection sockets are anonymous, so let's use
689 * PID/UID as pretty credentials instead */
691 r
= getpeercred(fd
, &ucred
);
695 if (asprintf(ret
, "PID "PID_FMT
"/UID "UID_FMT
, ucred
.pid
, ucred
.uid
) < 0)
701 /* For remote sockets we translate IPv6 addresses back to IPv4
702 * if applicable, since that's nicer. */
704 return sockaddr_pretty(&sa
.sa
, salen
, true, include_port
, ret
);
707 int getsockname_pretty(int fd
, char **ret
) {
708 union sockaddr_union sa
;
709 socklen_t salen
= sizeof(sa
);
714 if (getsockname(fd
, &sa
.sa
, &salen
) < 0)
717 /* For local sockets we do not translate IPv6 addresses back
718 * to IPv6 if applicable, since this is usually used for
719 * listening sockets where the difference between IPv4 and
722 return sockaddr_pretty(&sa
.sa
, salen
, false, true, ret
);
725 int socknameinfo_pretty(union sockaddr_union
*sa
, socklen_t salen
, char **_ret
) {
727 char host
[NI_MAXHOST
], *ret
;
731 r
= getnameinfo(&sa
->sa
, salen
, host
, sizeof(host
), NULL
, 0, IDN_FLAGS
);
733 int saved_errno
= errno
;
735 r
= sockaddr_pretty(&sa
->sa
, salen
, true, true, &ret
);
739 log_debug_errno(saved_errno
, "getnameinfo(%s) failed: %m", ret
);
750 int getnameinfo_pretty(int fd
, char **ret
) {
751 union sockaddr_union sa
;
752 socklen_t salen
= sizeof(sa
);
757 if (getsockname(fd
, &sa
.sa
, &salen
) < 0)
760 return socknameinfo_pretty(&sa
, salen
, ret
);
763 int socket_address_unlink(SocketAddress
*a
) {
766 if (socket_address_family(a
) != AF_UNIX
)
769 if (a
->sockaddr
.un
.sun_path
[0] == 0)
772 if (unlink(a
->sockaddr
.un
.sun_path
) < 0)
778 static const char* const netlink_family_table
[] = {
779 [NETLINK_ROUTE
] = "route",
780 [NETLINK_FIREWALL
] = "firewall",
781 [NETLINK_INET_DIAG
] = "inet-diag",
782 [NETLINK_NFLOG
] = "nflog",
783 [NETLINK_XFRM
] = "xfrm",
784 [NETLINK_SELINUX
] = "selinux",
785 [NETLINK_ISCSI
] = "iscsi",
786 [NETLINK_AUDIT
] = "audit",
787 [NETLINK_FIB_LOOKUP
] = "fib-lookup",
788 [NETLINK_CONNECTOR
] = "connector",
789 [NETLINK_NETFILTER
] = "netfilter",
790 [NETLINK_IP6_FW
] = "ip6-fw",
791 [NETLINK_DNRTMSG
] = "dnrtmsg",
792 [NETLINK_KOBJECT_UEVENT
] = "kobject-uevent",
793 [NETLINK_GENERIC
] = "generic",
794 [NETLINK_SCSITRANSPORT
] = "scsitransport",
795 [NETLINK_ECRYPTFS
] = "ecryptfs",
796 [NETLINK_RDMA
] = "rdma",
799 DEFINE_STRING_TABLE_LOOKUP_WITH_FALLBACK(netlink_family
, int, INT_MAX
);
801 static const char* const socket_address_bind_ipv6_only_table
[_SOCKET_ADDRESS_BIND_IPV6_ONLY_MAX
] = {
802 [SOCKET_ADDRESS_DEFAULT
] = "default",
803 [SOCKET_ADDRESS_BOTH
] = "both",
804 [SOCKET_ADDRESS_IPV6_ONLY
] = "ipv6-only"
807 DEFINE_STRING_TABLE_LOOKUP(socket_address_bind_ipv6_only
, SocketAddressBindIPv6Only
);
809 bool sockaddr_equal(const union sockaddr_union
*a
, const union sockaddr_union
*b
) {
813 if (a
->sa
.sa_family
!= b
->sa
.sa_family
)
816 if (a
->sa
.sa_family
== AF_INET
)
817 return a
->in
.sin_addr
.s_addr
== b
->in
.sin_addr
.s_addr
;
819 if (a
->sa
.sa_family
== AF_INET6
)
820 return memcmp(&a
->in6
.sin6_addr
, &b
->in6
.sin6_addr
, sizeof(a
->in6
.sin6_addr
)) == 0;
822 if (a
->sa
.sa_family
== AF_VSOCK
)
823 return a
->vm
.svm_cid
== b
->vm
.svm_cid
;
828 int fd_inc_sndbuf(int fd
, size_t n
) {
830 socklen_t l
= sizeof(value
);
832 r
= getsockopt(fd
, SOL_SOCKET
, SO_SNDBUF
, &value
, &l
);
833 if (r
>= 0 && l
== sizeof(value
) && (size_t) value
>= n
*2)
836 /* If we have the privileges we will ignore the kernel limit. */
839 if (setsockopt(fd
, SOL_SOCKET
, SO_SNDBUFFORCE
, &value
, sizeof(value
)) < 0)
840 if (setsockopt(fd
, SOL_SOCKET
, SO_SNDBUF
, &value
, sizeof(value
)) < 0)
846 int fd_inc_rcvbuf(int fd
, size_t n
) {
848 socklen_t l
= sizeof(value
);
850 r
= getsockopt(fd
, SOL_SOCKET
, SO_RCVBUF
, &value
, &l
);
851 if (r
>= 0 && l
== sizeof(value
) && (size_t) value
>= n
*2)
854 /* If we have the privileges we will ignore the kernel limit. */
857 if (setsockopt(fd
, SOL_SOCKET
, SO_RCVBUFFORCE
, &value
, sizeof(value
)) < 0)
858 if (setsockopt(fd
, SOL_SOCKET
, SO_RCVBUF
, &value
, sizeof(value
)) < 0)
863 static const char* const ip_tos_table
[] = {
864 [IPTOS_LOWDELAY
] = "low-delay",
865 [IPTOS_THROUGHPUT
] = "throughput",
866 [IPTOS_RELIABILITY
] = "reliability",
867 [IPTOS_LOWCOST
] = "low-cost",
870 DEFINE_STRING_TABLE_LOOKUP_WITH_FALLBACK(ip_tos
, int, 0xff);
872 bool ifname_valid(const char *p
) {
875 /* Checks whether a network interface name is valid. This is inspired by dev_valid_name() in the kernel sources
876 * but slightly stricter, as we only allow non-control, non-space ASCII characters in the interface name. We
877 * also don't permit names that only container numbers, to avoid confusion with numeric interface indexes. */
882 if (strlen(p
) >= IFNAMSIZ
)
885 if (dot_or_dot_dot(p
))
889 if ((unsigned char) *p
>= 127U)
892 if ((unsigned char) *p
<= 32U)
895 if (*p
== ':' || *p
== '/')
898 numeric
= numeric
&& (*p
>= '0' && *p
<= '9');
908 bool address_label_valid(const char *p
) {
913 if (strlen(p
) >= IFNAMSIZ
)
917 if ((uint8_t) *p
>= 127U)
920 if ((uint8_t) *p
<= 31U)
928 int getpeercred(int fd
, struct ucred
*ucred
) {
929 socklen_t n
= sizeof(struct ucred
);
936 r
= getsockopt(fd
, SOL_SOCKET
, SO_PEERCRED
, &u
, &n
);
940 if (n
!= sizeof(struct ucred
))
943 /* Check if the data is actually useful and not suppressed due
944 * to namespacing issues */
947 if (u
.uid
== UID_INVALID
)
949 if (u
.gid
== GID_INVALID
)
956 int getpeersec(int fd
, char **ret
) {
968 r
= getsockopt(fd
, SOL_SOCKET
, SO_PEERSEC
, s
, &n
);
979 r
= getsockopt(fd
, SOL_SOCKET
, SO_PEERSEC
, s
, &n
);
998 const struct sockaddr
*sa
, socklen_t len
,
1002 struct cmsghdr cmsghdr
;
1003 uint8_t buf
[CMSG_SPACE(sizeof(int))];
1005 struct msghdr mh
= {
1006 .msg_name
= (struct sockaddr
*) sa
,
1008 .msg_control
= &control
,
1009 .msg_controllen
= sizeof(control
),
1011 struct cmsghdr
*cmsg
;
1013 assert(transport_fd
>= 0);
1016 cmsg
= CMSG_FIRSTHDR(&mh
);
1017 cmsg
->cmsg_level
= SOL_SOCKET
;
1018 cmsg
->cmsg_type
= SCM_RIGHTS
;
1019 cmsg
->cmsg_len
= CMSG_LEN(sizeof(int));
1020 memcpy(CMSG_DATA(cmsg
), &fd
, sizeof(int));
1022 mh
.msg_controllen
= CMSG_SPACE(sizeof(int));
1023 if (sendmsg(transport_fd
, &mh
, MSG_NOSIGNAL
| flags
) < 0)
1029 int receive_one_fd(int transport_fd
, int flags
) {
1031 struct cmsghdr cmsghdr
;
1032 uint8_t buf
[CMSG_SPACE(sizeof(int))];
1034 struct msghdr mh
= {
1035 .msg_control
= &control
,
1036 .msg_controllen
= sizeof(control
),
1038 struct cmsghdr
*cmsg
, *found
= NULL
;
1040 assert(transport_fd
>= 0);
1043 * Receive a single FD via @transport_fd. We don't care for
1044 * the transport-type. We retrieve a single FD at most, so for
1045 * packet-based transports, the caller must ensure to send
1046 * only a single FD per packet. This is best used in
1047 * combination with send_one_fd().
1050 if (recvmsg(transport_fd
, &mh
, MSG_NOSIGNAL
| MSG_CMSG_CLOEXEC
| flags
) < 0)
1053 CMSG_FOREACH(cmsg
, &mh
) {
1054 if (cmsg
->cmsg_level
== SOL_SOCKET
&&
1055 cmsg
->cmsg_type
== SCM_RIGHTS
&&
1056 cmsg
->cmsg_len
== CMSG_LEN(sizeof(int))) {
1064 cmsg_close_all(&mh
);
1068 return *(int*) CMSG_DATA(found
);
1071 ssize_t
next_datagram_size_fd(int fd
) {
1075 /* This is a bit like FIONREAD/SIOCINQ, however a bit more powerful. The difference being: recv(MSG_PEEK) will
1076 * actually cause the next datagram in the queue to be validated regarding checksums, which FIONREAD doesn't
1077 * do. This difference is actually of major importance as we need to be sure that the size returned here
1078 * actually matches what we will read with recvmsg() next, as otherwise we might end up allocating a buffer of
1079 * the wrong size. */
1081 l
= recv(fd
, NULL
, 0, MSG_PEEK
|MSG_TRUNC
);
1083 if (IN_SET(errno
, EOPNOTSUPP
, EFAULT
))
1096 /* Some sockets (AF_PACKET) do not support null-sized recv() with MSG_TRUNC set, let's fall back to FIONREAD
1097 * for them. Checksums don't matter for raw sockets anyway, hence this should be fine. */
1099 if (ioctl(fd
, FIONREAD
, &k
) < 0)
1105 int flush_accept(int fd
) {
1107 struct pollfd pollfd
= {
1114 /* Similar to flush_fd() but flushes all incoming connection by accepting them and immediately closing them. */
1119 r
= poll(&pollfd
, 1, 0);
1129 cfd
= accept4(fd
, NULL
, NULL
, SOCK_NONBLOCK
|SOCK_CLOEXEC
);
1134 if (errno
== EAGAIN
)
1144 struct cmsghdr
* cmsg_find(struct msghdr
*mh
, int level
, int type
, socklen_t length
) {
1145 struct cmsghdr
*cmsg
;
1149 CMSG_FOREACH(cmsg
, mh
)
1150 if (cmsg
->cmsg_level
== level
&&
1151 cmsg
->cmsg_type
== type
&&
1152 (length
== (socklen_t
) -1 || length
== cmsg
->cmsg_len
))
1158 int socket_ioctl_fd(void) {
1161 /* Create a socket to invoke the various network interface ioctl()s on. Traditionally only AF_INET was good for
1162 * that. Since kernel 4.6 AF_NETLINK works for this too. We first try to use AF_INET hence, but if that's not
1163 * available (for example, because it is made unavailable via SECCOMP or such), we'll fall back to the more
1164 * generic AF_NETLINK. */
1166 fd
= socket(AF_INET
, SOCK_DGRAM
|SOCK_CLOEXEC
, 0);
1168 fd
= socket(AF_NETLINK
, SOCK_RAW
|SOCK_CLOEXEC
, NETLINK_GENERIC
);