udp.c

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/*
 *   This library 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.
 *
 *   This library 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 this library; if not, write to the Free Software
 *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */
 
/** Utility functions for managing UDP sockets
 *
 * @file src/lib/util/udp.c
 *
 * @copyright 2000-2003,2006 The FreeRADIUS server project
 */
RCSID("$Id: 2af2d7838ecfb236c94cfd6fbef7cc1a5b01ae5e $")
 
#include <freeradius-devel/util/log.h>
#include <freeradius-devel/util/socket.h>
#include <freeradius-devel/util/syserror.h>
#include <freeradius-devel/util/udp.h>
 
#define FR_DEBUG_STRERROR_PRINTF if (fr_debug_lvl) fr_strerror_printf
 
/** Send a packet via a UDP socket.
 *
 * @param[in] sock              we're reading from.
 * @param[in] flags             to pass to send(), or sendto()
 * @param[in] data              to data to send
 * @param[in] data_len          length of data to send
 * @return
 *      - 0 on success.
 *      - -1 on failure.
 */
int udp_send(fr_socket_t const *sock, int flags, void *data, size_t data_len)
{
        int ret;
 
        fr_assert(sock->type == SOCK_DGRAM);
 
        if (flags & UDP_FLAGS_CONNECTED) {
                ret = (send(sock->fd, data, data_len, 0) == (ssize_t)data_len) ? 0 : -1;
        } else {
                struct sockaddr_storage dst, src;
                socklen_t               sizeof_dst, sizeof_src;
 
                if (fr_ipaddr_to_sockaddr(&dst, &sizeof_dst,
                                          &sock->inet.dst_ipaddr, sock->inet.dst_port) < 0) return -1;
                if (fr_ipaddr_to_sockaddr(&src, &sizeof_src,
                                          &sock->inet.src_ipaddr, sock->inet.src_port) < 0) return -1;
 
                ret = sendfromto(sock->fd, data, data_len, 0,
                                 sock->inet.ifindex,
                                 (struct sockaddr *)&src, sizeof_src,
                                 (struct sockaddr *)&dst, sizeof_dst);
        }
 
        if (ret < 0) fr_strerror_printf("udp_send failed: %s", fr_syserror(errno));
 
        return ret;
}
 
 
/** Discard the next UDP packet
 *
 * @param[in] sockfd we're reading from.
 */
int udp_recv_discard(int sockfd)
{
        uint8_t                 data[4];
        struct sockaddr_storage src;
        socklen_t               sizeof_src = sizeof(src);
 
        return recvfrom(sockfd, data, sizeof(data), 0,
                        (struct sockaddr *)&src, &sizeof_src);
}
 
 
/** Peek at the header of a UDP packet.
 *
 * @param[in] sockfd we're reading from.
 * @param[out] data pointer where data will be written
 * @param[in] data_len length of data to read
 * @param[in] flags for things
 * @param[out] src_ipaddr of the packet.
 * @param[out] src_port of the packet.
 */
ssize_t udp_recv_peek(int sockfd, void *data, size_t data_len, int flags, fr_ipaddr_t *src_ipaddr, uint16_t *src_port)
{
        ssize_t                 peeked;
        struct sockaddr_storage src;
        socklen_t               sizeof_src = sizeof(src);
 
        if (!src_ipaddr || ((flags & UDP_FLAGS_CONNECTED) != 0)) {
                peeked = recv(sockfd, data, data_len, MSG_PEEK);
                if (peeked < 0) {
                        if ((errno == EAGAIN) || (errno == EINTR)) return 0;
                        return -1;
                }
 
                return peeked;
        }
 
        peeked = recvfrom(sockfd, data, data_len, MSG_PEEK, (struct sockaddr *)&src, &sizeof_src);
        if (peeked < 0) {
                if ((errno == EAGAIN) || (errno == EINTR)) return 0;
                return -1;
        }
 
        /*
         *      Convert AF.  If unknown, discard packet.
         */
        if (fr_ipaddr_from_sockaddr(src_ipaddr, src_port, &src, sizeof_src) < 0) {
                FR_DEBUG_STRERROR_PRINTF("Unknown address family");
                (void) udp_recv_discard(sockfd);
 
                return -1;
        }
 
        return peeked;
}
 
 
/** Read a UDP packet
 *
 * @param[in] sockfd            we're reading from.
 * @param[in] flags             for things
 * @param[out] socket_out       Information about the src/dst address of the packet
 *                              and the interface it was received on.
 * @param[out] data             pointer where data will be written
 * @param[in] data_len          length of data to read
 * @param[out] when             the packet was received.
 * @return
 *      - > 0 on success (number of bytes read).
 *      - < 0 on failure.
 */
ssize_t udp_recv(int sockfd, int flags,
                 fr_socket_t *socket_out, void *data, size_t data_len, fr_time_t *when)
{
        int                     sock_flags = 0;
        struct sockaddr_storage src;
        struct sockaddr_storage dst;
        socklen_t               sizeof_src = sizeof(src);
        socklen_t               sizeof_dst = sizeof(dst);
        ssize_t                 slen;
 
        if ((flags & UDP_FLAGS_PEEK) != 0) sock_flags |= MSG_PEEK;
 
        if (when) *when = fr_time_wrap(0);
 
        /*
         *      Always initialise the output socket structure
         */
        *socket_out = (fr_socket_t){
                .fd = sockfd,
                .type = SOCK_DGRAM,
        };
 
        /*
         *      Connected sockets already know src/dst IP/port
         */
        if ((flags & UDP_FLAGS_CONNECTED) != 0) {
                slen = recv(sockfd, data, data_len, sock_flags);
                goto done;
        }
 
        /*
         *      Receive the packet.  The OS will discard any data in the
         *      packet after "len" bytes.
         */
        slen = recvfromto(sockfd, data, data_len, sock_flags,
                          &socket_out->inet.ifindex,
                          (struct sockaddr *)&src, &sizeof_src,
                          (struct sockaddr *)&dst, &sizeof_dst,
                          when);
        if (slen <= 0) goto done;
 
        if (fr_ipaddr_from_sockaddr(&socket_out->inet.src_ipaddr, &socket_out->inet.src_port, &src, sizeof_src) < 0) {
                fr_strerror_const_push("Failed converting src sockaddr to ipaddr");
                return -1;
        }
        if (fr_ipaddr_from_sockaddr(&socket_out->inet.dst_ipaddr, &socket_out->inet.dst_port, &dst, sizeof_dst) < 0) {
                fr_strerror_const_push("Failed converting dst sockaddr to ipaddr");
                return -1;
        }
 
done:
        if (slen < 0) {
                if ((errno == EWOULDBLOCK) || (errno == EAGAIN)) return 0;
 
                fr_strerror_printf("Failed reading socket: %s", fr_syserror(errno));
                return slen;
        }
 
        /*
         *      We didn't get it from the kernel
         *      so use our own time source.
         */
        if (when && fr_time_eq(*when, fr_time_wrap(0))) *when = fr_time();
 
        return slen;
}