orcasim::models::orca::udp_server Class Reference

#include <NetBridge.hpp>

Public Member Functions
	udp_server (const std::string &addr, int port)
	Initialize a UDP server object. More...
	~udp_server ()
	Clean up the UDP server. More...
int	get_socket () const
	The socket used by this UDP server. More...
int	get_port () const
	The port used by this UDP server. More...
std::string	get_addr () const
	Return the address of this UDP server. More...
int	recv (char *msg, size_t max_size)
	Wait on a message. More...
int	timed_recv (char *msg, size_t max_size, int max_wait_ms)
	Wait for data to come in. More...

Private Attributes
int	f_socket
int	f_port
std::string	f_addr
struct addrinfo *	f_addrinfo

Detailed Description

Definition at line 93 of file NetBridge.hpp.

Constructor & Destructor Documentation

udp_server()

udp_server::udp_server	(	const std::string &	addr,
		int	port
	)

Initialize a UDP server object.

This function initializes a UDP server object making it ready to receive messages.

The server address and port are specified in the constructor so if you need to receive messages from several different addresses and/or port, you'll have to create a server for each.

The address is a string and it can represent an IPv4 or IPv6 address.

Note that this function calls connect() to connect the socket to the specified address. To accept data on different UDP addresses and ports, multiple UDP servers must be created.

Note

The socket is open in this process. If you fork() or exec() then the socket will be closed by the operating system.

Warning

We only make use of the first address found by getaddrinfo(). All the other addresses are ignored.

Exceptions

udp_client_server_runtime_error

The udp_client_server_runtime_error exception is raised when the address and port combinaison cannot be resolved or if the socket cannot be opened.

Parameters

[in]	addr	The address we receive on.
[in]	port	The port we receive from.

Definition at line 508 of file NetBridge.cpp.

    : f_port(port)
    , f_addr(addr) {
    char decimal_port[16];
    snprintf(decimal_port, sizeof(decimal_port), "%d", f_port);
    decimal_port[sizeof(decimal_port) / sizeof(decimal_port[0]) - 1] = '\0';
    struct addrinfo hints;
    memset(&hints, 0, sizeof(hints));
    hints.ai_family = AF_UNSPEC;
    hints.ai_socktype = SOCK_DGRAM;
    hints.ai_protocol = IPPROTO_UDP;
    int r(getaddrinfo(addr.c_str(), decimal_port, &hints, &f_addrinfo));

    if (r != 0 || f_addrinfo == NULL) {
        throw udp_client_server_runtime_error(
            ("invalid address or port for UDP socket: \"" + addr + ":"
                + decimal_port + "\"").c_str());
    }

    f_socket = socket(f_addrinfo->ai_family, SOCK_DGRAM |
        SOCK_CLOEXEC, IPPROTO_UDP);

    if (f_socket == -1) {
        freeaddrinfo(f_addrinfo);
        throw udp_client_server_runtime_error(
            ("could not create UDP socket for: \"" + addr + ":" + decimal_port
                + "\"").c_str());
    }
    r = bind(f_socket, f_addrinfo->ai_addr, f_addrinfo->ai_addrlen);
    if (r != 0) {
        freeaddrinfo(f_addrinfo);
        close(f_socket);
        throw udp_client_server_runtime_error(
            ("could not bind UDP socket with: \"" + addr + ":" + decimal_port
                + "\"").c_str());
    }
}

~udp_server()

udp_server::~udp_server

(

)

Clean up the UDP server.

This function frees the address info structures and close the socket.

Definition at line 550 of file NetBridge.cpp.

                        {
    freeaddrinfo(f_addrinfo);
    close(f_socket);
}

Member Function Documentation

get_addr()

std::string udp_server::get_addr

(

)

const

Return the address of this UDP server.

This function returns a verbatim copy of the address as passed to the constructor of the UDP server (i.e. it does not return the canonalized version of the address.)

Returns

The address as passed to the constructor.

Definition at line 585 of file NetBridge.cpp.

                                     {
    return f_addr;
}

get_port()

int udp_server::get_port

(

)

const

The port used by this UDP server.

This function returns the port attached to the UDP server. It is a copy of the port specified in the constructor.

Returns

The port of the UDP server.

Definition at line 573 of file NetBridge.cpp.

                               {
    return f_port;
}

get_socket()

int udp_server::get_socket

(

)

const

The socket used by this UDP server.

This function returns the socket identifier. It can be useful if you are doing a select() on many sockets.

Returns

The socket of this UDP server.

Definition at line 562 of file NetBridge.cpp.

                                 {
    return f_socket;
}

recv()

int udp_server::recv	(	char *	msg,
		size_t	max_size
	)

Wait on a message.

This function waits until a message is received on this UDP server. There are no means to return from this function except by receiving a message. Remember that UDP does not have a connect state so whether another process quits does not change the status of this UDP server and thus it continues to wait forever.

Note that you may change the type of socket by making it non-blocking (use the get_socket() to retrieve the socket identifier) in which case this function will not block if no message is available. Instead it returns immediately.

Parameters

[in]	msg	The buffer where the message is saved.
[in]	max_size	The maximum size the message (i.e. size of the msg buffer.)

Returns

The number of bytes read or -1 if an error occurs.

Definition at line 607 of file NetBridge.cpp.

                                               {
    return ::recv(f_socket, msg, max_size, 0);
}

timed_recv()

int udp_server::timed_recv	(	char *	msg,
		size_t	max_size,
		int	max_wait_ms
	)

Wait for data to come in.

This function waits for a given amount of time for data to come in. If no data comes in after max_wait_ms, the function returns with -1 and errno set to EAGAIN.

The socket is expected to be a blocking socket (the default,) although it is possible to setup the socket as non-blocking if necessary for some other reason.

This function blocks for a maximum amount of time as defined by max_wait_ms. It may return sooner with an error or a message.

Parameters

[in]	msg	The buffer where the message will be saved.
[in]	max_size	The size of the msg buffer in bytes.
[in]	max_wait_ms	The maximum number of milliseconds to wait for a message.

Returns

-1 if an error occurs or the function timed out, the number of bytes received otherwise.

23/03/2019: Anderson Removed last two parameters to avoid -Werror=restrict original call: => int retval = select(f_socket + 1, &s, &s, &s, &timeout); TODO: make sure that these parameters won't break the function

Definition at line 630 of file NetBridge.cpp.

                                                                      {
    fd_set s;
    FD_ZERO(&s);
    FD_SET(f_socket, &s);
    struct timeval timeout;
    timeout.tv_sec = max_wait_ms / 1000;
    timeout.tv_usec = (max_wait_ms % 1000) * 1000;

    int retval = select(f_socket + 1, &s, 0, 0, &timeout);
    if (retval == -1) {
        // select() set errno accordingly
        return -1;
    }

    if (retval > 0) {
        // our socket has data
        return ::recv(f_socket, msg, max_size, 0);
    }

    // our socket has no data
    errno = EAGAIN;
    return -1;
}

Member Data Documentation

f_addr

std::string orcasim::models::orca::udp_server::f_addr

private

Definition at line 108 of file NetBridge.hpp.

f_addrinfo

struct addrinfo* orcasim::models::orca::udp_server::f_addrinfo

private

Definition at line 109 of file NetBridge.hpp.

f_port

int orcasim::models::orca::udp_server::f_port

private

Definition at line 107 of file NetBridge.hpp.

f_socket

int orcasim::models::orca::udp_server::f_socket

private

Definition at line 106 of file NetBridge.hpp.

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The documentation for this class was generated from the following files:

• models/orca-virtual-ethernet/include/NetBridge.hpp
• models/orca-virtual-ethernet/src/NetBridge.cpp