hdhomerun_sock_posix.c

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/*
 * hdhomerun_sock_posix.c
 *
 * Copyright © 2010 Silicondust USA Inc. <www.silicondust.com>.
 *
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 * 
 * As a special exception to the GNU Lesser General Public License,
 * you may link, statically or dynamically, an application with a
 * publicly distributed version of the Library to produce an
 * executable file containing portions of the Library, and
 * distribute that executable file under terms of your choice,
 * without any of the additional requirements listed in clause 4 of
 * the GNU Lesser General Public License.
 * 
 * By "a publicly distributed version of the Library", we mean
 * either the unmodified Library as distributed by Silicondust, or a
 * modified version of the Library that is distributed under the
 * conditions defined in the GNU Lesser General Public License.
 */

/*
 * Implementation notes:
 *
 * API specifies timeout for each operation (or zero for non-blocking).
 *
 * It is not possible to rely on the OS socket timeout as this will fail to
 * detect the command-response situation where data is sent successfully and
 * the other end chooses not to send a response (other than the TCP ack).
 *
 * The select() cannot be used with high socket numbers (typically max 1024)
 * so the code works as follows:
 * - Use non-blocking sockets to allow operation without select.
 * - Use select where safe (low socket numbers).
 * - Poll with short sleep when select cannot be used safely.
 */

#include "hdhomerun.h"

#include <net/if.h>
#include <sys/ioctl.h>
#ifndef SIOCGIFCONF
#include <sys/sockio.h>
#endif
#ifndef _SIZEOF_ADDR_IFREQ
#define _SIZEOF_ADDR_IFREQ(x) sizeof(x)
#endif

int hdhomerun_local_ip_info(struct hdhomerun_local_ip_info_t ip_info_list[], int max_count)
{
        int sock = socket(AF_INET, SOCK_DGRAM, 0);
        if (sock == HDHOMERUN_SOCK_INVALID) {
                return -1;
        }

        struct ifconf ifc;
        size_t ifreq_buffer_size = 1024;

        while (1) {
                ifc.ifc_len = ifreq_buffer_size;
                ifc.ifc_buf = (char *)malloc(ifreq_buffer_size);
                if (!ifc.ifc_buf) {
                        close(sock);
                        return -1;
                }

                memset(ifc.ifc_buf, 0, ifreq_buffer_size);

                if (ioctl(sock, SIOCGIFCONF, &ifc) != 0) {
                        free(ifc.ifc_buf);
                        close(sock);
                        return -1;
                }

                if (ifc.ifc_len < ifreq_buffer_size) {
                        break;
                }

                free(ifc.ifc_buf);
                ifreq_buffer_size += 1024;
        }

        char *ptr = ifc.ifc_buf;
        char *end = ifc.ifc_buf + ifc.ifc_len;

        int count = 0;
        while (ptr <= end) {
                struct ifreq *ifr = (struct ifreq *)ptr;
                ptr += _SIZEOF_ADDR_IFREQ(*ifr);

                if (ioctl(sock, SIOCGIFADDR, ifr) != 0) {
                        continue;
                }

                struct sockaddr_in *ip_addr_in = (struct sockaddr_in *)&(ifr->ifr_addr);
                uint32_t ip_addr = ntohl(ip_addr_in->sin_addr.s_addr);
                if (ip_addr == 0) {
                        continue;
                }

                if (ioctl(sock, SIOCGIFNETMASK, ifr) != 0) {
                        continue;
                }

                struct sockaddr_in *subnet_mask_in = (struct sockaddr_in *)&(ifr->ifr_addr);
                uint32_t subnet_mask = ntohl(subnet_mask_in->sin_addr.s_addr);

                struct hdhomerun_local_ip_info_t *ip_info = &ip_info_list[count++];
                ip_info->ip_addr = ip_addr;
                ip_info->subnet_mask = subnet_mask;

                if (count >= max_count) {
                        break;
                }
        }

        free(ifc.ifc_buf);
        close(sock);
        return count;
}

hdhomerun_sock_t hdhomerun_sock_create_udp(void)
{
        /* Create socket. */
        hdhomerun_sock_t sock = (hdhomerun_sock_t)socket(AF_INET, SOCK_DGRAM, 0);
        if (sock == -1) {
                return HDHOMERUN_SOCK_INVALID;
        }

        /* Set non-blocking */
        if (fcntl(sock, F_SETFL, O_NONBLOCK) != 0) {
                close(sock);
                return HDHOMERUN_SOCK_INVALID;
        }

        /* Allow broadcast. */
        int sock_opt = 1;
        setsockopt(sock, SOL_SOCKET, SO_BROADCAST, (char *)&sock_opt, sizeof(sock_opt));

        /* Success. */
        return sock;
}

hdhomerun_sock_t hdhomerun_sock_create_tcp(void)
{
        /* Create socket. */
        hdhomerun_sock_t sock = (hdhomerun_sock_t)socket(AF_INET, SOCK_STREAM, 0);
        if (sock == -1) {
                return HDHOMERUN_SOCK_INVALID;
        }

        /* Set non-blocking */
        if (fcntl(sock, F_SETFL, O_NONBLOCK) != 0) {
                close(sock);
                return HDHOMERUN_SOCK_INVALID;
        }

        /* Success. */
        return sock;
}

void hdhomerun_sock_destroy(hdhomerun_sock_t sock)
{
        close(sock);
}

int hdhomerun_sock_getlasterror(void)
{
        return errno;
}

uint32_t hdhomerun_sock_getsockname_addr(hdhomerun_sock_t sock)
{
        struct sockaddr_in sock_addr;
        socklen_t sockaddr_size = sizeof(sock_addr);

        if (getsockname(sock, (struct sockaddr *)&sock_addr, &sockaddr_size) != 0) {
                return 0;
        }

        return ntohl(sock_addr.sin_addr.s_addr);
}

uint16_t hdhomerun_sock_getsockname_port(hdhomerun_sock_t sock)
{
        struct sockaddr_in sock_addr;
        socklen_t sockaddr_size = sizeof(sock_addr);

        if (getsockname(sock, (struct sockaddr *)&sock_addr, &sockaddr_size) != 0) {
                return 0;
        }

        return ntohs(sock_addr.sin_port);
}

uint32_t hdhomerun_sock_getpeername_addr(hdhomerun_sock_t sock)
{
        struct sockaddr_in sock_addr;
        socklen_t sockaddr_size = sizeof(sock_addr);

        if (getpeername(sock, (struct sockaddr *)&sock_addr, &sockaddr_size) != 0) {
                return 0;
        }

        return ntohl(sock_addr.sin_addr.s_addr);
}

uint32_t hdhomerun_sock_getaddrinfo_addr(hdhomerun_sock_t sock, const char *name)
{
        struct addrinfo hints;
        memset(&hints, 0, sizeof(hints));
        hints.ai_family = AF_INET;
        hints.ai_socktype = SOCK_STREAM;
        hints.ai_protocol = IPPROTO_TCP;

        struct addrinfo *sock_info;
        if (getaddrinfo(name, "", &hints, &sock_info) != 0) {
                return 0;
        }

        struct sockaddr_in *sock_addr = (struct sockaddr_in *)sock_info->ai_addr;
        uint32_t addr = ntohl(sock_addr->sin_addr.s_addr);

        freeaddrinfo(sock_info);
        return addr;
}

bool_t hdhomerun_sock_bind(hdhomerun_sock_t sock, uint32_t local_addr, uint16_t local_port, bool_t allow_reuse)
{
        int sock_opt = allow_reuse;
        setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (char *)&sock_opt, sizeof(sock_opt));

        struct sockaddr_in sock_addr;
        memset(&sock_addr, 0, sizeof(sock_addr));
        sock_addr.sin_family = AF_INET;
        sock_addr.sin_addr.s_addr = htonl(local_addr);
        sock_addr.sin_port = htons(local_port);

        if (bind(sock, (struct sockaddr *)&sock_addr, sizeof(sock_addr)) != 0) {
                return FALSE;
        }

        return TRUE;
}

static bool_t hdhomerun_sock_wait_for_read_event(hdhomerun_sock_t sock, uint64_t stop_time)
{
        uint64_t current_time = getcurrenttime();
        if (current_time >= stop_time) {
                return FALSE;
        }

        if (sock < FD_SETSIZE) {
                uint64_t timeout = stop_time - current_time;
                struct timeval t;
                t.tv_sec = timeout / 1000;
                t.tv_usec = (timeout % 1000) * 1000;

                fd_set readfds;
                FD_ZERO(&readfds);
                FD_SET(sock, &readfds);

                fd_set errorfds;
                FD_ZERO(&errorfds);
                FD_SET(sock, &errorfds);

                if (select(sock + 1, &readfds, NULL, &errorfds, &t) <= 0) {
                        return FALSE;
                }
                if (!FD_ISSET(sock, &readfds)) {
                        return FALSE;
                }
        } else {
                uint64_t delay = stop_time - current_time;
                if (delay > 5) {
                        delay = 5;
                }

                msleep_approx(delay);
        }

        return TRUE;
}

static bool_t hdhomerun_sock_wait_for_write_event(hdhomerun_sock_t sock, uint64_t stop_time)
{
        uint64_t current_time = getcurrenttime();
        if (current_time >= stop_time) {
                return FALSE;
        }

        if (sock < FD_SETSIZE) {
                uint64_t timeout = stop_time - current_time;
                struct timeval t;
                t.tv_sec = timeout / 1000;
                t.tv_usec = (timeout % 1000) * 1000;

                fd_set writefds;
                FD_ZERO(&writefds);
                FD_SET(sock, &writefds);

                fd_set errorfds;
                FD_ZERO(&errorfds);
                FD_SET(sock, &errorfds);

                if (select(sock + 1, NULL, &writefds, &errorfds, &t) <= 0) {
                        return FALSE;
                }
                if (!FD_ISSET(sock, &writefds)) {
                        return FALSE;
                }
        } else {
                uint64_t delay = stop_time - current_time;
                if (delay > 5) {
                        delay = 5;
                }

                msleep_approx(delay);
        }

        return TRUE;
}

bool_t hdhomerun_sock_connect(hdhomerun_sock_t sock, uint32_t remote_addr, uint16_t remote_port, uint64_t timeout)
{
        struct sockaddr_in sock_addr;
        memset(&sock_addr, 0, sizeof(sock_addr));
        sock_addr.sin_family = AF_INET;
        sock_addr.sin_addr.s_addr = htonl(remote_addr);
        sock_addr.sin_port = htons(remote_port);

        if (connect(sock, (struct sockaddr *)&sock_addr, sizeof(sock_addr)) == 0) {
                return TRUE;
        }

        uint64_t stop_time = getcurrenttime() + timeout;

        /*
         * getpeername() is used to detect if connect succeeded. Bug - cygwin
         * will return getpeername success even if the connect process hasn't
         * completed. This first call to select is used to work around the
         * problem (at least for low numbered sockets where select is used).
         */
        if (!hdhomerun_sock_wait_for_write_event(sock, stop_time)) {
                return FALSE;
        }

        while (1) {
                struct sockaddr_in sock_addr;
                socklen_t sockaddr_size = sizeof(sock_addr);
                if (getpeername(sock, (struct sockaddr *)&sock_addr, &sockaddr_size) == 0) {
                        return TRUE;
                }

                if (errno != ENOTCONN) {
                        return FALSE;
                }

                if (!hdhomerun_sock_wait_for_write_event(sock, stop_time)) {
                        return FALSE;
                }
        }
}

bool_t hdhomerun_sock_send(hdhomerun_sock_t sock, const void *data, size_t length, uint64_t timeout)
{
        uint64_t stop_time = getcurrenttime() + timeout;
        const uint8_t *ptr = (const uint8_t *)data;

        while (1) {
                int ret = send(sock, ptr, length, 0);
                if (ret >= (int)length) {
                        return TRUE;
                }

                if (ret > 0) {
                        ptr += ret;
                        length -= ret;
                }

                if (errno == EINPROGRESS) {
                        errno = EWOULDBLOCK;
                }
                if (errno != EWOULDBLOCK) {
                        return FALSE;
                }

                if (!hdhomerun_sock_wait_for_write_event(sock, stop_time)) {
                        return FALSE;
                }
        }
}

bool_t hdhomerun_sock_sendto(hdhomerun_sock_t sock, uint32_t remote_addr, uint16_t remote_port, const void *data, size_t length, uint64_t timeout)
{
        uint64_t stop_time = getcurrenttime() + timeout;
        const uint8_t *ptr = (const uint8_t *)data;

        while (1) {
                struct sockaddr_in sock_addr;
                memset(&sock_addr, 0, sizeof(sock_addr));
                sock_addr.sin_family = AF_INET;
                sock_addr.sin_addr.s_addr = htonl(remote_addr);
                sock_addr.sin_port = htons(remote_port);

                int ret = sendto(sock, ptr, length, 0, (struct sockaddr *)&sock_addr, sizeof(sock_addr));
                if (ret >= (int)length) {
                        return TRUE;
                }

                if (ret > 0) {
                        ptr += ret;
                        length -= ret;
                }

                if (errno == EINPROGRESS) {
                        errno = EWOULDBLOCK;
                }
                if (errno != EWOULDBLOCK) {
                        return FALSE;
                }

                if (!hdhomerun_sock_wait_for_write_event(sock, stop_time)) {
                        return FALSE;
                }
        }
}

bool_t hdhomerun_sock_recv(hdhomerun_sock_t sock, void *data, size_t *length, uint64_t timeout)
{
        uint64_t stop_time = getcurrenttime() + timeout;

        while (1) {
                int ret = recv(sock, data, *length, 0);
                if (ret > 0) {
                        *length = ret;
                        return TRUE;
                }

                if (errno == EINPROGRESS) {
                        errno = EWOULDBLOCK;
                }
                if (errno != EWOULDBLOCK) {
                        return FALSE;
                }

                if (!hdhomerun_sock_wait_for_read_event(sock, stop_time)) {
                        return FALSE;
                }
        }
}

bool_t hdhomerun_sock_recvfrom(hdhomerun_sock_t sock, uint32_t *remote_addr, uint16_t *remote_port, void *data, size_t *length, uint64_t timeout)
{
        uint64_t stop_time = getcurrenttime() + timeout;

        while (1) {
                struct sockaddr_in sock_addr;
                memset(&sock_addr, 0, sizeof(sock_addr));
                socklen_t sockaddr_size = sizeof(sock_addr);

                int ret = recvfrom(sock, data, *length, 0, (struct sockaddr *)&sock_addr, &sockaddr_size);
                if (ret > 0) {
                        *remote_addr = ntohl(sock_addr.sin_addr.s_addr);
                        *remote_port = ntohs(sock_addr.sin_port);
                        *length = ret;
                        return TRUE;
                }

                if (errno == EINPROGRESS) {
                        errno = EWOULDBLOCK;
                }
                if (errno != EWOULDBLOCK) {
                        return FALSE;
                }

                if (!hdhomerun_sock_wait_for_read_event(sock, stop_time)) {
                        return FALSE;
                }
        }
}

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