src/basic/socket-util.h

/* SPDX-License-Identifier: LGPL-2.1+ */
#pragma once

/***
  This file is part of systemd.

  Copyright 2010 Lennart Poettering

  systemd is free software; you can redistribute it and/or modify it
  under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation; either version 2.1 of the License, or
  (at your option) any later version.

  systemd is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License
  along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/

#include <netinet/ether.h>
#include <netinet/in.h>
#include <stdbool.h>
#include <stddef.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/un.h>
#include <linux/netlink.h>
#include <linux/if_infiniband.h>
#include <linux/if_packet.h>

#include "macro.h"
#include "missing.h"
#include "util.h"

union sockaddr_union {
        /* The minimal, abstract version */
        struct sockaddr sa;

        /* The libc provided version that allocates "enough room" for every protocol */
        struct sockaddr_storage storage;

        /* Protoctol-specific implementations */
        struct sockaddr_in in;
        struct sockaddr_in6 in6;
        struct sockaddr_un un;
        struct sockaddr_nl nl;
        struct sockaddr_ll ll;
        struct sockaddr_vm vm;

        /* Ensure there is enough space to store Infiniband addresses */
        uint8_t ll_buffer[offsetof(struct sockaddr_ll, sll_addr) + CONST_MAX(ETH_ALEN, INFINIBAND_ALEN)];

        /* Ensure there is enough space after the AF_UNIX sun_path for one more NUL byte, just to be sure that the path
         * component is always followed by at least one NUL byte. */
        uint8_t un_buffer[sizeof(struct sockaddr_un) + 1];
};

typedef struct SocketAddress {
        union sockaddr_union sockaddr;

        /* We store the size here explicitly due to the weird
         * sockaddr_un semantics for abstract sockets */
        socklen_t size;

        /* Socket type, i.e. SOCK_STREAM, SOCK_DGRAM, ... */
        int type;

        /* Socket protocol, IPPROTO_xxx, usually 0, except for netlink */
        int protocol;
} SocketAddress;

typedef enum SocketAddressBindIPv6Only {
        SOCKET_ADDRESS_DEFAULT,
        SOCKET_ADDRESS_BOTH,
        SOCKET_ADDRESS_IPV6_ONLY,
        _SOCKET_ADDRESS_BIND_IPV6_ONLY_MAX,
        _SOCKET_ADDRESS_BIND_IPV6_ONLY_INVALID = -1
} SocketAddressBindIPv6Only;

#define socket_address_family(a) ((a)->sockaddr.sa.sa_family)

const char* socket_address_type_to_string(int t) _const_;
int socket_address_type_from_string(const char *s) _pure_;

int socket_address_parse(SocketAddress *a, const char *s);
int socket_address_parse_and_warn(SocketAddress *a, const char *s);
int socket_address_parse_netlink(SocketAddress *a, const char *s);
int socket_address_print(const SocketAddress *a, char **p);
int socket_address_verify(const SocketAddress *a) _pure_;
int socket_address_unlink(SocketAddress *a);

bool socket_address_can_accept(const SocketAddress *a) _pure_;

int socket_address_listen(
                const SocketAddress *a,
                int flags,
                int backlog,
                SocketAddressBindIPv6Only only,
                const char *bind_to_device,
                bool reuse_port,
                bool free_bind,
                bool transparent,
                mode_t directory_mode,
                mode_t socket_mode,
                const char *label);
int make_socket_fd(int log_level, const char* address, int type, int flags);

bool socket_address_is(const SocketAddress *a, const char *s, int type);
bool socket_address_is_netlink(const SocketAddress *a, const char *s);

bool socket_address_matches_fd(const SocketAddress *a, int fd);

bool socket_address_equal(const SocketAddress *a, const SocketAddress *b) _pure_;

const char* socket_address_get_path(const SocketAddress *a);

bool socket_ipv6_is_supported(void);

int sockaddr_port(const struct sockaddr *_sa, unsigned *port);

int sockaddr_pretty(const struct sockaddr *_sa, socklen_t salen, bool translate_ipv6, bool include_port, char **ret);
int getpeername_pretty(int fd, bool include_port, char **ret);
int getsockname_pretty(int fd, char **ret);

int socknameinfo_pretty(union sockaddr_union *sa, socklen_t salen, char **_ret);

const char* socket_address_bind_ipv6_only_to_string(SocketAddressBindIPv6Only b) _const_;
SocketAddressBindIPv6Only socket_address_bind_ipv6_only_from_string(const char *s) _pure_;
SocketAddressBindIPv6Only parse_socket_address_bind_ipv6_only_or_bool(const char *s);

int netlink_family_to_string_alloc(int b, char **s);
int netlink_family_from_string(const char *s) _pure_;

bool sockaddr_equal(const union sockaddr_union *a, const union sockaddr_union *b);

int fd_inc_sndbuf(int fd, size_t n);
int fd_inc_rcvbuf(int fd, size_t n);

int ip_tos_to_string_alloc(int i, char **s);
int ip_tos_from_string(const char *s);

bool ifname_valid(const char *p);
bool address_label_valid(const char *p);

int getpeercred(int fd, struct ucred *ucred);
int getpeersec(int fd, char **ret);
int getpeergroups(int fd, gid_t **ret);

int send_one_fd_sa(int transport_fd,
                   int fd,
                   const struct sockaddr *sa, socklen_t len,
                   int flags);
#define send_one_fd(transport_fd, fd, flags) send_one_fd_sa(transport_fd, fd, NULL, 0, flags)
int receive_one_fd(int transport_fd, int flags);

ssize_t next_datagram_size_fd(int fd);

int flush_accept(int fd);

#define CMSG_FOREACH(cmsg, mh)                                          \
        for ((cmsg) = CMSG_FIRSTHDR(mh); (cmsg); (cmsg) = CMSG_NXTHDR((mh), (cmsg)))

struct cmsghdr* cmsg_find(struct msghdr *mh, int level, int type, socklen_t length);

/*
 * Certain hardware address types (e.g Infiniband) do not fit into sll_addr
 * (8 bytes) and run over the structure. This macro returns the correct size that
 * must be passed to kernel.
 */
#define SOCKADDR_LL_LEN(sa)                                             \
        ({                                                              \
                const struct sockaddr_ll *_sa = &(sa);                  \
                size_t _mac_len = sizeof(_sa->sll_addr);                \
                assert(_sa->sll_family == AF_PACKET);                   \
                if (be16toh(_sa->sll_hatype) == ARPHRD_ETHER)           \
                        _mac_len = MAX(_mac_len, (size_t) ETH_ALEN);    \
                if (be16toh(_sa->sll_hatype) == ARPHRD_INFINIBAND)      \
                        _mac_len = MAX(_mac_len, (size_t) INFINIBAND_ALEN); \
                offsetof(struct sockaddr_ll, sll_addr) + _mac_len;      \
        })

/* Covers only file system and abstract AF_UNIX socket addresses, but not unnamed socket addresses. */
#define SOCKADDR_UN_LEN(sa)                                             \
        ({                                                              \
                const struct sockaddr_un *_sa = &(sa);                  \
                assert(_sa->sun_family == AF_UNIX);                     \
                offsetof(struct sockaddr_un, sun_path) +                \
                        (_sa->sun_path[0] == 0 ?                        \
                         1 + strnlen(_sa->sun_path+1, sizeof(_sa->sun_path)-1) : \
                         strnlen(_sa->sun_path, sizeof(_sa->sun_path))); \
        })

int socket_ioctl_fd(void);