ardupilot/libraries/AP_HAL/utility/Socket.cpp

/*
   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 3 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, see <http://www.gnu.org/licenses/>.
 */
/*
  simple socket handling class for systems with BSD socket API
 */

#include <AP_HAL.h>
#if HAL_OS_SOCKETS

#include "Socket.h"

/*
  constructor
 */
SocketAPM::SocketAPM(bool _datagram) :
datagram(_datagram)
{
    fd = socket(AF_INET, datagram?SOCK_DGRAM:SOCK_STREAM, 0);
    fcntl(fd, F_SETFD, FD_CLOEXEC);
    int one = 1;
    setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &one, sizeof(one));
}

SocketAPM::~SocketAPM()
{
    if (fd != -1) {
        ::close(fd);
        fd = -1;
    }
}

void SocketAPM::make_sockaddr(const char *address, uint16_t port, struct sockaddr_in &sockaddr)
{
    memset(&sockaddr, 0, sizeof(sockaddr));

#ifdef HAVE_SOCK_SIN_LEN
    sockaddr.sin_len = sizeof(sockaddr);
#endif
    sockaddr.sin_port = htons(port);
    sockaddr.sin_family = AF_INET;
    sockaddr.sin_addr.s_addr = inet_addr(address);
}

/*
  connect the socket
 */
bool SocketAPM::connect(const char *address, uint16_t port)
{
    struct sockaddr_in sockaddr;
    make_sockaddr(address, port, sockaddr);

    if (::connect(fd, (struct sockaddr *)&sockaddr, sizeof(sockaddr)) != 0) {
        return false;
    }
    return true;
}

/*
  bind the socket
 */
bool SocketAPM::bind(const char *address, uint16_t port)
{
    struct sockaddr_in sockaddr;
    make_sockaddr(address, port, sockaddr);

    if (::bind(fd, (struct sockaddr *)&sockaddr, sizeof(sockaddr)) != 0) {
        return false;
    }
    return true;
}


/*
  set SO_REUSEADDR
 */
void SocketAPM::reuseaddress(void)
{
    int one = 1;
    setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
}

/*
  set blocking state
 */
void SocketAPM::set_blocking(bool blocking)
{
    if (blocking) {
        fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) & ~O_NONBLOCK);
    } else {
        fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) | O_NONBLOCK);
    }
}

/*
  send some data
 */
ssize_t SocketAPM::send(const void *buf, size_t size)
{
    return ::send(fd, buf, size, 0);
}

/*
  send some data
 */
ssize_t SocketAPM::sendto(const void *buf, size_t size, const char *address, uint16_t port)
{
    struct sockaddr_in sockaddr;
    make_sockaddr(address, port, sockaddr);
    return ::sendto(fd, buf, size, 0, (struct sockaddr *)&sockaddr, sizeof(sockaddr));
}

/*
  receive some data
 */
ssize_t SocketAPM::recv(void *buf, size_t size, uint32_t timeout_ms)
{
    if (!pollin(timeout_ms)) {
        return -1;
    }
    
    return ::recvfrom(fd, buf, size, MSG_DONTWAIT, NULL, NULL);
}


/*
  return true if there is pending data for input
 */
bool SocketAPM::pollin(uint32_t timeout_ms)
{
    fd_set fds;
    struct timeval tv;

    FD_ZERO(&fds);
    FD_SET(fd, &fds);

    tv.tv_sec = timeout_ms / 1000;
    tv.tv_usec = (timeout_ms % 1000) * 1000UL;

    if (select(fd+1, &fds, NULL, NULL, &tv) != 1) {
        return false;
    }
    return true;
}

#endif // HAL_OS_SOCKETS