socket.c

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/*
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or (at
 *   your option) any later version.
 *
 *   This program 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 General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */
 
/** Functions for establishing and managing low level sockets
 *
 * @file src/lib/util/socket.c
 *
 * @author Arran Cudbard-Bell (a.cudbardb@freeradius.org)
 * @author Alan DeKok (aland@freeradius.org)
 *
 * @copyright 2015 The FreeRADIUS project
 */
 
#include <freeradius-devel/util/debug.h>
#include <freeradius-devel/util/misc.h>
#include <freeradius-devel/util/socket.h>
#include <freeradius-devel/util/syserror.h>
#include <freeradius-devel/util/udpfromto.h>
#include <freeradius-devel/util/value.h>
#include <freeradius-devel/util/cap.h>
 
#include <fcntl.h>
#include <ifaddrs.h>
 
/** Resolve a named service to a port
 *
 * @param[in] proto     The protocol. Either IPPROTO_TCP or IPPROTO_UDP.
 * @param[in] port_name The service name, i.e. "radius".
 * @return
 *      - > 0 the port port_name resolves to.
 *      - < 0 on error.
 */
static int socket_port_from_service(int proto, char const *port_name)
{
        struct servent  *service;
        char const      *proto_name;
 
        if (!port_name) {
                fr_strerror_const("No port specified");
                return -1;
        }
 
        switch (proto) {
        case IPPROTO_UDP:
                proto_name = "udp";
                break;
 
        case IPPROTO_TCP:
                proto_name = "tcp";
                break;
 
#ifdef IPPROTO_SCTP
        case IPPROTO_SCTP:
                proto_name = "sctp";
                break;
#endif
 
        default:
                fr_strerror_printf("Unrecognised proto %i", proto);
                return -1;
        }
 
        service = getservbyname(port_name, proto_name);
        if (!service) {
                fr_strerror_printf("Unknown service %s", port_name);
                return -1;
        }
 
        return ntohs(service->s_port);
}
 
#ifdef HAVE_STRUCT_SOCKADDR_IN6
/** Restrict wildcard sockets to v6 only
 *
 * If we don't do this we get v4 and v6 packets coming in on the same
 * socket, which is weird.
 *
 * @param[in] sockfd to modify.
 * @param[in] ipaddr we will be binding to.
 * @return
 *      - 0 on success.
 *      - -1 on failure.
 */
static int socket_inaddr_any_v6only(int sockfd, fr_ipaddr_t const *ipaddr)
{
        /*
         *      Listening on '::' does NOT get you IPv4 to
         *      IPv6 mapping.  You've got to listen on an IPv4
         *      address, too.  This makes the rest of the server
         *      design a little simpler.
         */
        if (ipaddr->af == AF_INET6) {
#  ifdef IPV6_V6ONLY
                /* unconst for emscripten/musl */
                if (IN6_IS_ADDR_UNSPECIFIED(UNCONST(struct in6_addr *, &ipaddr->addr.v6))) {
                        int on = 1;
 
                        if (setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
                                       (char *)&on, sizeof(on)) < 0) {
                                fr_strerror_printf("Failed setting socket to IPv6 only: %s", fr_syserror(errno));
                                return -1;
                        }
                }
#  endif /* IPV6_V6ONLY */
        }
        return 0;
}
#else
static int socket_inaddr_any_v6only(UNUSED int sockfd, UNUSED fr_ipaddr_t const *ipaddr)
{
        return 0;
}
#endif
 
#if (defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DONT)) || defined(IP_DONTFRAG)
/** Set the don't fragment bit
 *
 * @param[in] sockfd    to set don't fragment bit for.
 * @param[in] af        of the socket.
 * @return
 *      - 0 on success.
 *      - -1 on failure.
 */
static int socket_dont_fragment(int sockfd, int af)
{
        /*
         *      Set the "don't fragment" flag on UDP sockets.  Most
         *      routers don't have good support for fragmented UDP
         *      packets.
         */
        if (af == AF_INET) {
                int flag;
 
#  if defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DONT)
                /*
                 *      Disable PMTU discovery.  On Linux, this
                 *      also makes sure that the "don't fragment"
                 *      flag is zero.
                 */
                flag = IP_PMTUDISC_DONT;
 
                if (setsockopt(sockfd, IPPROTO_IP, IP_MTU_DISCOVER, &flag, sizeof(flag)) < 0) {
                        fr_strerror_printf("Failed disabling PMTU discovery: %s", fr_syserror(errno));
                        return -1;
                }
#  endif
 
#  if defined(IP_DONTFRAG)
                /*
                 *      Ensure that the "don't fragment" flag is zero.
                 */
                flag = 0;
 
                if (setsockopt(sockfd, IPPROTO_IP, IP_DONTFRAG, &flag, sizeof(flag)) < 0) {
                        fr_strerror_printf("Failed setting don't fragment flag: %s", fr_syserror(errno));
                        return -1;
                }
#  endif
        }
 
        return 0;
}
#else
static int socket_dont_fragment(UNUSED int sockfd, UNUSED int af)
{
        return 0;
}
#endif  /* lots of things */
 
/** Bind a UDP/TCP v4/v6 socket to a given ipaddr src port, and interface.
 *
 * Use one of:
 * - fr_socket_server_udp - for non-connected socket.
 * - fr_socket_server_tcp
 * ...to open a file descriptor, then call this function to bind the socket to an IP address.
 *
 * @param[in] sockfd            the socket which opened by fr_socket_server_*.
 * @param[in] ifname            to bind to.
 * @param[in,out] src_ipaddr    The IP address to bind to.  Will be updated to the IP address
 *                              that was actually bound to. Pass NULL to just bind to an interface.
 * @param[in] src_port          the port to bind to.  NULL if any port is allowed.
 
 * @return
 *      - 0 on success
 *      - -1 on failure.
 */
int fr_socket_bind(int sockfd, char const *ifname, fr_ipaddr_t *src_ipaddr, uint16_t *src_port)
{
        int                             ret;
        uint16_t                        my_port = 0;
        fr_ipaddr_t                     my_ipaddr;
        struct sockaddr_storage         salocal;
        socklen_t                       salen;
#ifdef HAVE_NET_IF_H
        unsigned int scope_id = 0;
#endif
 
        /*
         *      Clear the thread local error stack as we may
         *      push multiple errors onto the stack, and this
         *      is likely to be the function which returns
         *      the "original" error.
         */
        fr_strerror_clear();
 
        if (src_port) my_port = *src_port;
        if (src_ipaddr) {
                my_ipaddr = *src_ipaddr;
        } else {
                my_ipaddr = (fr_ipaddr_t) {
                        .af = AF_UNSPEC
                };
        }
 
#ifdef HAVE_CAPABILITY_H
        /*
         *      If we're binding to a special port as non-root, then
         *      check capabilities.  If we're root, we already have
         *      equivalent capabilities so we don't need to check.
         */
        if (src_port && (*src_port < 1024) && (geteuid() != 0)) {
                (void)fr_cap_enable(CAP_NET_BIND_SERVICE, CAP_EFFECTIVE);       /* Sets error on failure, which will be seen if the bind fails */
        }
#endif
 
        /*
         *      Bind to a device BEFORE touching IP addresses.
         */
        if (ifname) {
#ifdef HAVE_NET_IF_H
                scope_id = if_nametoindex(ifname);
                if (!scope_id) {
                        fr_strerror_printf_push("Failed finding interface %s: %s", ifname, fr_syserror(errno));
                        return -1;
                }
 
                /*
                 *      If the scope ID hasn't already been set, then
                 *      set it.  This allows us to get the scope from the interface name.
                 */
                if ((my_ipaddr.scope_id != 0) && (scope_id != my_ipaddr.scope_id)) {
                        fr_strerror_printf_push("Cannot bind to interface %s: Socket is already bound "
                                                "to another interface", ifname);
                        return -1;
                }
#endif
 
#ifdef SO_BINDTODEVICE
                /*
                 *      The caller didn't specify a scope_id, but we
                 *      have one from above.  Call "bind to device",
                 *      and set the scope_id.
                 */
                if (!my_ipaddr.scope_id) {
                        /*
                         *      The internet hints that CAP_NET_RAW
                         *      is required to use SO_BINDTODEVICE.
                         *
                         *      This function also sets fr_strerror()
                         *      on failure, which will be seen if the
                         *      bind fails.  If the bind succeeds,
                         *      then we don't really care that the
                         *      capability change has failed.  We must
                         *      already have that capability.
                         */
#ifdef HAVE_CAPABILITY_H
                        (void)fr_cap_enable(CAP_NET_RAW, CAP_EFFECTIVE);
#endif
                        ret = setsockopt(sockfd, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
                        if (ret < 0) {
                                fr_strerror_printf_push("Failed binding socket to interface %s: %s",
                                                        ifname, fr_syserror(errno));
                                return -1;
                        } /* else it worked. */
 
                        /*
                         *      Set the scope ID.
                         */
                        my_ipaddr.scope_id = scope_id;
                }
 
                /*
                 *      SO_BINDTODEVICE succeeded, so we're always
                 *      bound to the socket.
                 */
 
#elif defined(IP_BOUND_IF) || defined(IPV6_BOUND_IF)
                {
                        int idx = scope_id;
 
                        if (my_ipaddr.af == AF_INET) {
                                if (unlikely(setsockopt(sockfd, IPPROTO_IP, IP_BOUND_IF, &idx, sizeof(idx)) < 0)) {
                                error:
                                        fr_strerror_printf_push("Failed binding socket to interface %s: %s",
                                                                ifname, fr_syserror(errno));
                                        return -1;
                                }
 
                        } else if (my_ipaddr.af == AF_INET6) {
                                if (unlikely(setsockopt(sockfd, IPPROTO_IPV6, IPV6_BOUND_IF, &idx, sizeof(idx)) < 0)) goto error;
 
                        } else {
                                fr_strerror_printf("Invalid address family for 'interface = ...'");
                                return -1;
                        }
 
                        my_ipaddr.scope_id = scope_id;
                }
 
#else
                {
                        struct ifaddrs *list = NULL;
                        bool bound = false;
 
                        /*
                         *      Troll through all interfaces to see if there's
                         */
                        if (getifaddrs(&list) == 0) {
                                struct ifaddrs *i;
 
                                for (i = list; i != NULL; i = i->ifa_next) {
                                        if (i->ifa_addr && i->ifa_name && (strcmp(i->ifa_name, ifname) == 0)) {
                                                /*
                                                 *      IPv4, and there's either no src_ip, OR src_ip is INADDR_ANY,
                                                 *      it's a match.
                                                 *
                                                 *      We also update my_ipaddr to point to this particular IP,
                                                 *      so that we can later bind() to it.  This gets us the same
                                                 *      effect as SO_BINDTODEVICE.
                                                 */
                                                if ((i->ifa_addr->sa_family == AF_INET) &&
                                                    (!src_ipaddr || fr_ipaddr_is_inaddr_any(src_ipaddr))) {
                                                        (void) fr_ipaddr_from_ifaddr(&my_ipaddr, i->ifa_addr);
                                                        my_ipaddr.scope_id = scope_id;
                                                        bound = true;
                                                        break;
                                                }
 
                                                /*
                                                 *      The caller specified a source IP, and we find a matching
                                                 *      address family.  Allow it.
                                                 *
                                                 *      Note that we do NOT check for matching IPs here.  If we did,
                                                 *      then binding to an interface and the *wrong* IP would get us
                                                 *      a "bind to device is unsupported" message.
                                                 *
                                                 *      Instead we say "yes, we found a matching interface", and then
                                                 *      allow the bind() call below to run.  If that fails, we get a
                                                 *      "Can't assign requested address" error, which is more informative.
                                                 */
                                                if (src_ipaddr && (src_ipaddr->af == i->ifa_addr->sa_family)) {
                                                        my_ipaddr.scope_id = scope_id;
                                                        bound = true;
                                                        break;
                                                }
                                        }
                                }
 
                                freeifaddrs(list);
 
                                if (!bound) {
                                        /*
                                         *      IPv4: no link local addresses,
                                         *      and no bind to device.
                                         */
                                        fr_strerror_printf_push("Bind to interface %s failed: Unable to match "
                                                                "interface with the given IP address.", ifname);
                                        return -1;
                                }
                        } else {
                                fr_strerror_printf_push("Bind to interface %s failed, unable to get list of interfaces: %s",
                                                        ifname, fr_syserror(errno));
                                return -1;
                        }
                }
#endif
        } /* else no interface was passed in */
 
        /*
         *      Don't bind to an IP address if there's no src IP address.
         */
        if (my_ipaddr.af == AF_UNSPEC) goto done;
 
        /*
         *      Set up sockaddr stuff.
         */
        if (fr_ipaddr_to_sockaddr(&salocal, &salen, &my_ipaddr, my_port) < 0) return -1;
 
        ret = bind(sockfd, (struct sockaddr *) &salocal, salen);
        if (ret < 0) {
                fr_strerror_printf_push("Bind failed with source address %pV:%pV on interface %s: %s",
                                        src_ipaddr ? fr_box_ipaddr(*src_ipaddr) : fr_box_strvalue("*"),
                                        src_port ? fr_box_int16(*src_port) : fr_box_strvalue("*"),
                                        ifname ? ifname : "*",
                                        fr_syserror(errno));
                return ret;
        }
 
        if (!src_port) goto done;
 
        /*
         *      FreeBSD jail issues.  We bind to 0.0.0.0, but the
         *      kernel instead binds us to a 1.2.3.4.  So once the
         *      socket is bound, ask it what it's IP address is.
         */
        salen = sizeof(salocal);
        memset(&salocal, 0, salen);
        if (getsockname(sockfd, (struct sockaddr *) &salocal, &salen) < 0) {
                fr_strerror_printf_push("Failed getting socket name: %s", fr_syserror(errno));
                return -1;
        }
 
        if (fr_ipaddr_from_sockaddr(&my_ipaddr, &my_port, &salocal, salen) < 0) return -1;
 
#ifdef HAVE_NET_IF_H
        /*
         * fr_ipaddr_from_sockaddr clears scope_id for IPv4
         */
        if (ifname && scope_id && (my_ipaddr.af == AF_INET)) my_ipaddr.scope_id = scope_id;
#endif
        *src_port = my_port;
        *src_ipaddr = my_ipaddr;
 
done:
#ifdef HAVE_CAPABILITY_H
        /*
         *      Clear any errors we may have produced in the
         *      capabilities check.
         */
        fr_strerror_clear();
#endif
        return 0;
}
 
#ifdef HAVE_SYS_UN_H
/** Open a Unix socket
 *
 * @note If the file doesn't exist then errno will be set to ENOENT.
 *
 * The following code demonstrates using this function with a connection timeout:
 @code {.c}
   sockfd = fr_socket_client_unix(path, true);
   if (sockfd < 0) {
        fr_perror();
        fr_exit_now(1);
   }
   if ((errno == EINPROGRESS) && (fr_socket_wait_for_connect(sockfd, timeout) < 0)) {
   error:
        fr_perror();
        close(sockfd);
        goto error;
   }
   //Optionally, if blocking operation is required
   if (fr_blocking(sockfd) < 0) goto error;
 @endcode
 *
 * @param path          to the file bound to the unix socket.
 * @param async         Whether to set the socket to nonblocking, allowing use of
 *                      #fr_socket_wait_for_connect.
 * @return
 *      - Socket FD on success.
 *      - -1 on failure.
 */
int fr_socket_client_unix(char const *path, bool async)
{
        int                     sockfd = -1;
        size_t                  len;
        socklen_t               socklen;
        struct sockaddr_un      saremote;
 
        len = strlen(path);
        if (len >= sizeof(saremote.sun_path)) {
                fr_strerror_printf("Path too long, maximum length is %zu", sizeof(saremote.sun_path) - 1);
                errno = EINVAL;
                return -1;
        }
 
        sockfd = socket(AF_UNIX, SOCK_STREAM, 0);
        if (sockfd < 0) {
                fr_strerror_printf("Failed creating UNIX socket: %s", fr_syserror(errno));
                return -1;
        }
 
        if (async && (fr_nonblock(sockfd) < 0)) {
                close(sockfd);
                return -1;
        }
 
        saremote.sun_family = AF_UNIX;
        memcpy(saremote.sun_path, path, len + 1); /* SUN_LEN does strlen */
 
        socklen = SUN_LEN(&saremote);
 
        /*
         *      Although we ignore SIGPIPE, some operating systems
         *      like BSD and OSX ignore the ignoring.
         *
         *      Fortunately, those operating systems usually support
         *      SO_NOSIGPIPE, to prevent them raising the signal in
         *      the first place.
         */
#ifdef SO_NOSIGPIPE
        {
                int set = 1;
 
                setsockopt(sockfd, SOL_SOCKET, SO_NOSIGPIPE, (void *)&set, sizeof(int));
        }
#endif
 
        if (connect(sockfd, (struct sockaddr *)&saremote, socklen) < 0) {
                /*
                 *      POSIX says the only time we will get this,
                 *      is if the socket has been marked as
                 *      nonblocking. This is not an error, the caller
                 *      must check the state of errno, and wait for
                 *      the connection to complete.
                 */
                if (errno == EINPROGRESS) return sockfd;
 
                close(sockfd);
                fr_strerror_printf("Failed connecting to %s: %s", path, fr_syserror(errno));
 
                return -1;
        }
        return sockfd;
}
#else
int fr_socket_client_unix(UNUSED char const *path, UNUSED bool async)
{
        fprintf(stderr, "Unix domain sockets not supported on this system");
        return -1;
}
#endif /* WITH_SYS_UN_H */
 
#if defined SO_BINDTODEVICE || defined IP_BOUND_IF
static inline CC_HINT(always_inline) int socket_bind_ifname(int sockfd, char const *ifname)
#else
static inline CC_HINT(always_inline) int socket_bind_ifname(UNUSED int sockfd, UNUSED char const *ifname)
#endif
{
#if defined(SO_BINDTODEVICE)
        if (setsockopt(sockfd, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname)) < 0) {
                fr_strerror_printf("Failed binding socket to %s: %s", ifname, fr_syserror(errno));
                return -1;
        }
#elif defined(IP_BOUND_IF)
        {
                int idx = if_nametoindex(ifname);
                if (idx == 0) {
                error:
                        fr_strerror_printf("Failed binding socket to %s: %s", ifname, fr_syserror(errno));
                        return -1;
                }
                if (unlikely(setsockopt(sockfd, IPPROTO_IP, IP_BOUND_IF, &idx, sizeof(idx)) < 0)) goto error;
        }
#else
        fr_strerror_const("Binding sockets to interfaces not supported on this platform");
        return -1;
#endif
 
        return 0;
}
 
/** Establish a connected UDP socket
 *
 * Connected UDP sockets can be used with write(), unlike unconnected sockets
 * which must be used with sendto and recvfrom.
 *
 * The following code demonstrates using this function with a connection timeout:
 @code {.c}
   sockfd = fr_socket_client_udp(NULL, NULL, NULL, ipaddr, port, true);
   if (sockfd < 0) {
        fr_perror();
        fr_exit_now(1);
   }
   if ((errno == EINPROGRESS) && (fr_socket_wait_for_connect(sockfd, timeout) < 0)) {
   error:
        fr_perror();
        close(sockfd);
        goto error;
   }
   //Optionally, if blocking operation is required
   if (fr_blocking(sockfd) < 0) goto error;
 @endcode
 *
 * @param[in] ifname            If non-NULL, bind the socket to this interface.
 * @param[in,out] src_ipaddr    to bind socket to, may be NULL if socket is not bound to any specific
 *                              address.  If non-null, the bound IP is copied here, too.
 * @param[out] src_port         The source port we were bound to, may be NULL.
 * @param[in] dst_ipaddr        Where to send datagrams.
 * @param[in] dst_port          Where to send datagrams.
 * @param[in] async             Whether to set the socket to nonblocking, allowing use of
 *                              #fr_socket_wait_for_connect.
 * @return
 *      - FD on success.
 *      - -1 on failure.
 */
int fr_socket_client_udp(char const *ifname, fr_ipaddr_t *src_ipaddr, uint16_t *src_port,
                         fr_ipaddr_t const *dst_ipaddr, uint16_t dst_port, bool async)
{
        int                     sockfd;
        struct sockaddr_storage salocal;
        socklen_t               salen;
 
        if (!dst_ipaddr) return -1;
 
        sockfd = socket(dst_ipaddr->af, SOCK_DGRAM, 0);
        if (sockfd < 0) {
                fr_strerror_printf("Error creating UDP socket: %s", fr_syserror(errno));
                return -1;
        }
 
        if (async && (fr_nonblock(sockfd) < 0)) {
        error:
                close(sockfd);
                return -1;
        }
 
        /*
         *      Although we ignore SIGPIPE, some operating systems
         *      like BSD and OSX ignore the ignoring.
         *
         *      Fortunately, those operating systems usually support
         *      SO_NOSIGPIPE, to prevent them raising the signal in
         *      the first place.
         */
#ifdef SO_NOSIGPIPE
        {
                int set = 1;
 
                setsockopt(sockfd, SOL_SOCKET, SO_NOSIGPIPE, (void *)&set, sizeof(int));
        }
#endif
 
        if (unlikely(fr_socket_bind(sockfd, ifname, src_ipaddr, src_port) < 0)) goto error;
 
        /*
         *      And now get our destination
         */
        if (fr_ipaddr_to_sockaddr(&salocal, &salen, dst_ipaddr, dst_port) < 0) {
                close(sockfd);
                return -1;
        }
 
        if (connect(sockfd, (struct sockaddr *) &salocal, salen) < 0) {
                /*
                 *      POSIX says the only time we will get this,
                 *      is if the socket has been marked as
                 *      nonblocking. This is not an error, the caller
                 *      must check the state of errno, and wait for
                 *      the connection to complete.
                 */
                if (errno == EINPROGRESS) return sockfd;
 
                fr_strerror_printf("Failed connecting socket: %s", fr_syserror(errno));
                close(sockfd);
                return -1;
        }
 
        return sockfd;
}
 
/** Establish a connected TCP socket
 *
 * The following code demonstrates using this function with a connection timeout:
 @code {.c}
   sockfd = fr_socket_client_tcp(NULL, NULL, ipaddr, port, true);
   if (sockfd < 0) {
        fr_perror();
        fr_exit_now(1);
   }
   if ((errno == EINPROGRESS) && (fr_socket_wait_for_connect(sockfd, timeout) < 0)) {
   error:
        fr_perror();
        close(sockfd);
        goto error;
   }
   //Optionally, if blocking operation is required
   if (fr_blocking(sockfd) < 0) goto error;
 @endcode
 *
 * @param[in] ifname    If non-NULL, bind the socket to this interface.
 * @param src_ipaddr    to bind socket to, may be NULL if socket is not bound to any specific
 *                      address.
 * @param dst_ipaddr    Where to connect to.
 * @param dst_port      Where to connect to.
 * @param async         Whether to set the socket to nonblocking, allowing use of
 *                      #fr_socket_wait_for_connect.
 * @return
 *      - FD on success
 *      - -1 on failure.
 */
int fr_socket_client_tcp(char const *ifname, fr_ipaddr_t *src_ipaddr,
                         fr_ipaddr_t const *dst_ipaddr, uint16_t dst_port, bool async)
{
        int                     sockfd;
        struct sockaddr_storage salocal;
        socklen_t               salen;
 
        if (!dst_ipaddr) return -1;
 
        sockfd = socket(dst_ipaddr->af, SOCK_STREAM, 0);
        if (sockfd < 0) {
                fr_strerror_printf("Error creating TCP socket: %s", fr_syserror(errno));
                return sockfd;
        }
 
        if (async && (fr_nonblock(sockfd) < 0)) {
        error:
                close(sockfd);
                return -1;
        }
 
        if (unlikely(fr_socket_bind(sockfd, ifname, src_ipaddr, NULL) < 0)) goto error;
 
        if (fr_ipaddr_to_sockaddr(&salocal, &salen, dst_ipaddr, dst_port) < 0) goto error;
 
        /*
         *      Although we ignore SIGPIPE, some operating systems
         *      like BSD and OSX ignore the ignoring.
         *
         *      Fortunately, those operating systems usually support
         *      SO_NOSIGPIPE, to prevent them raising the signal in
         *      the first place.
         */
#ifdef SO_NOSIGPIPE
        {
                int set = 1;
 
                setsockopt(sockfd, SOL_SOCKET, SO_NOSIGPIPE, (void *)&set, sizeof(int));
        }
#endif
 
        if (connect(sockfd, (struct sockaddr *) &salocal, salen) < 0) {
                /*
                 *      POSIX says the only time we will get this,
                 *      is if the socket has been marked as
                 *      nonblocking. This is not an error, the caller
                 *      must check the state of errno, and wait for
                 *      the connection to complete.
                 */
                if (errno == EINPROGRESS) return sockfd;
 
                fr_strerror_printf("Failed connecting socket: %s", fr_syserror(errno));
                close(sockfd);
                return -1;
        }
 
        return sockfd;
}
 
/** Wait for a socket to be connected, with an optional timeout
 *
 * @note On error the caller is expected to ``close(sockfd)``.
 *
 * @param sockfd the socket to wait on.
 * @param timeout How long to wait for socket to open.
 * @return
 *      - 0 on success.
 *      - -1 on connection error.
 *      - -2 on timeout.
 *      - -3 on select error.
 */
int fr_socket_wait_for_connect(int sockfd, fr_time_delta_t timeout)
{
        int     ret;
        fd_set  error_set;
        fd_set  write_set;      /* POSIX says sockets are open when they become writable */
 
        FD_ZERO(&error_set);
        FD_ZERO(&write_set);
 
        FD_SET(sockfd, &error_set);
        FD_SET(sockfd, &write_set);
 
        /* Don't let signals mess up the select */
        do {
                ret = select(sockfd + 1, NULL, &write_set, &error_set, &fr_time_delta_to_timeval(timeout));
        } while ((ret == -1) && (errno == EINTR));
 
        switch (ret) {
        case 1: /* ok (maybe) */
        {
                int error;
                socklen_t socklen = sizeof(error);
 
                if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, (void *)&error, &socklen)) {
                        fr_strerror_printf("Failed connecting socket: %s", fr_syserror(errno));
                        return -1;
                }
 
                if (FD_ISSET(sockfd, &error_set)) {
                        fr_strerror_const("Failed connecting socket: Unknown error");
                        return -1;
                }
        }
                return 0;
 
        case 0: /* timeout */
                if (!fr_cond_assert(fr_time_delta_ispos(timeout))) return -1;
                fr_strerror_printf("Connection timed out after %pVs", fr_box_time_delta(timeout));
                return -2;
 
        case -1: /* select error */
                fr_strerror_printf("Failed waiting for connection: %s", fr_syserror(errno));
                return -3;
 
        default:
                (void)fr_cond_assert(0);
                return -1;
        }
}
 
/** Open an IPv4/IPv6 unconnected UDP socket
 *
 * Function name is a bit of a misnomer as it can also be used to create client sockets too,
 * such is the nature of UDP.
 *
 * @param[in] src_ipaddr        The IP address to listen on
 * @param[in,out] src_port      the port to listen on.  If *port == 0, the resolved
 *                              service port will be written here.
 * @param[in] port_name         if *port == 0, the name of the port
 * @param[in] async             whether we block or not on reads and writes
 * @return
 *      - Socket FD on success.
 *      - -1 on failure.
 */
int fr_socket_server_udp(fr_ipaddr_t const *src_ipaddr, uint16_t *src_port, char const *port_name, bool async)
{
        int             sockfd;
        uint16_t        my_port = 0;
 
        if (src_port) my_port = *src_port;
 
        /*
         *      Check IP looks OK
         */
        if (!src_ipaddr || ((src_ipaddr->af != AF_INET) && (src_ipaddr->af != AF_INET6))) {
                fr_strerror_const("No address specified");
                return -1;
        }
 
        /*
         *      Check we have a port value or stuff we can resolve to a port
         */
        if (!my_port && port_name) {
                int ret;
 
                ret = socket_port_from_service(IPPROTO_UDP, port_name);
                if (ret < 0) return -1;
 
                my_port = ret;
        }
 
        /*
         *      Open the socket
         */
        sockfd = socket(src_ipaddr->af, SOCK_DGRAM, IPPROTO_UDP);
        if (sockfd < 0) {
                fr_strerror_printf("Failed creating UDP socket: %s", fr_syserror(errno));
                return -1;
        }
 
        /*
         *      Make it non-blocking if asked
         */
        if (async && (fr_nonblock(sockfd) < 0)) {
        error:
                close(sockfd);
                return -1;
        }
 
        /*
         *      Don't allow child processes to inherit the socket
         */
        if (fr_cloexec(sockfd) < 0) goto error;
 
        /*
         *      Initialize udpfromto for UDP sockets.
         */
        if (udpfromto_init(sockfd, src_ipaddr->af) != 0) {
                fr_strerror_printf("Failed initializing udpfromto: %s", fr_syserror(errno));
                goto error;
        }
 
        /*
         *      Make sure we don't get v4 and v6 packets on inaddr_any sockets.
         */
        if (socket_inaddr_any_v6only(sockfd, src_ipaddr) < 0) goto error;
 
        /*
         *      Ensure don't fragment bit is set
         */
        if (socket_dont_fragment(sockfd, src_ipaddr->af) < 0) goto error;
 
#ifdef SO_TIMESTAMP
        {
                int on = 1;
 
                /*
                 *      Enable receive timestamps, these should reflect
                 *      when the packet was received, not when it was read
                 *      from the socket.
                 */
                if (setsockopt(sockfd, SOL_SOCKET, SO_TIMESTAMP, &on, sizeof(int)) < 0) {
                        close(sockfd);
                        fr_strerror_printf("Failed enabling socket timestamps: %s", fr_syserror(errno));
                        return -1;
                }
        }
#endif
 
        if (src_port) *src_port = my_port;
 
        return sockfd;
}
 
/** Open an IPv4/IPv6 TCP socket
 *
 * @param[in] src_ipaddr        The IP address to listen on
 * @param[in,out] src_port      the port to listen on.  If *port == 0, the resolved
 *                              service port will be written here.
 *                              NULL if any port is allowed.
 * @param[in] port_name         if *port == 0, the name of the port
 * @param[in] async             whether we block or not on reads and writes
 * @return
 *      - Socket FD on success.
 *      - -1 on failure.
 */
int fr_socket_server_tcp(fr_ipaddr_t const *src_ipaddr, uint16_t *src_port, char const *port_name, bool async)
{
        int             sockfd;
        uint16_t        my_port = 0;
 
        if (src_port) my_port = *src_port;
 
        /*
         *      Check IP looks OK
         */
        if (!src_ipaddr || ((src_ipaddr->af != AF_INET) && (src_ipaddr->af != AF_INET6))) {
                fr_strerror_const("No address specified");
                return -1;
        }
 
        /*
         *      Check we have a port value or stuff we can resolve to a port
         */
        if (!my_port && port_name) {
                int ret;
 
                ret = socket_port_from_service(IPPROTO_TCP, port_name);
                if (ret < 0) return -1;
 
                my_port = ret;
        }
 
        /*
         *      Open the socket
         */
        sockfd = socket(src_ipaddr->af, SOCK_STREAM, IPPROTO_TCP);
        if (sockfd < 0) {
                fr_strerror_printf("Failed creating TCP socket: %s", fr_syserror(errno));
                return -1;
        }
 
        /*
         *      Make it non-blocking if asked
         */
        if (async && (fr_nonblock(sockfd) < 0)) {
        error:
                close(sockfd);
                return -1;
        }
 
        /*
         *      Don't allow child processes to inherit the socket
         */
        if (fr_cloexec(sockfd) < 0) goto error;
 
        /*
         *      Make sure we don't get v4 and v6 packets on inaddr_any sockets.
         */
        if (socket_inaddr_any_v6only(sockfd, src_ipaddr) < 0) goto error;
 
        {
                int on = 1;
 
                if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) < 0) {
                        close(sockfd);
                        fr_strerror_printf("Failed to reuse address: %s", fr_syserror(errno));
                        return -1;
                }
        }
 
        if (src_port) *src_port = my_port;
 
        return sockfd;
}
 
/** Print an #fr_socket_t to a string.
 *
 */
ssize_t fr_socket_to_str(char *out, size_t outlen, fr_socket_t const *sock, bool received)
{
        ssize_t slen;
        static char const *sense[2] = { "to", "from" };
        char *src_ip, src_ip_buffer[FR_IPADDR_STRLEN];
        char *dst_ip, dst_ip_buffer[FR_IPADDR_STRLEN];
#ifdef WITH_IFINDEX_NAME_RESOLUTION
        char if_name[IFNAMSIZ];
#endif
 
        switch (sock->af) {
        case AF_INET:
        case AF_INET6:
                src_ip = fr_inet_ntop(src_ip_buffer, sizeof(src_ip_buffer), &sock->inet.src_ipaddr);
                if (!src_ip) return 0;
 
                dst_ip = fr_inet_ntop(dst_ip_buffer, sizeof(dst_ip_buffer), &sock->inet.dst_ipaddr);
                if (!dst_ip) return 0;
 
                slen = snprintf(out, outlen, "%s %s%s%s:%u %s %s%s%s:%u",
                                sense[received],
                                sock->af == AF_INET6 ? "[" : "",
                                src_ip,
                                sock->af == AF_INET6 ? "]" : "",
                                sock->inet.src_port,
 
                                sense[!received],
                                sock->af == AF_INET6 ? "[" : "",
                                dst_ip,
                                sock->af == AF_INET6 ? "]" : "",
                                sock->inet.dst_port);
 
#ifndef WITH_IFINDEX_NAME_RESOLUTION
                break;
#else
 
                /*
                 *      Catch errors.
                 */
                if (slen <= 0) return slen;
                if ((size_t) slen > outlen) return -slen;
 
                /*
                 *      No ifindex, we don't need to do anything else.
                 */
                if (!sock->inet.ifindex) return slen;
 
                out += slen;
                outlen -= slen;
 
                slen = snprintf(out, outlen, " via %s",
                                fr_ifname_from_ifindex(if_name, sock->inet.ifindex));
#endif
                break;
 
        case AF_LOCAL:
                slen = snprintf(out, outlen, "%s unix path %s", sense[received], sock->unix.path);
                break;
 
        case AF_FR_FILENAME:
                slen = snprintf(out, outlen, "%s filename %s", sense[received], sock->file.path);
                break;
 
        case AF_FR_VIRTUAL_SERVER:
                slen = snprintf(out, outlen, "%s virtual server %s", sense[received], sock->virtual.server);
                break;
 
        default:
                fr_strerror_printf("Invalid address family %d", sock->af);
                return -1;
        }
 
        if (slen <= 0) return slen;
        if ((size_t) slen > outlen) return -slen;
 
        return slen;
}