diff options
Diffstat (limited to 'src/UDPClient')
| -rw-r--r-- | src/UDPClient/UDPClient.cpp | 142 | ||||
| -rw-r--r-- | src/UDPClient/UDPClient.h | 44 |
2 files changed, 186 insertions, 0 deletions
diff --git a/src/UDPClient/UDPClient.cpp b/src/UDPClient/UDPClient.cpp new file mode 100644 index 0000000..1d427ba --- /dev/null +++ b/src/UDPClient/UDPClient.cpp @@ -0,0 +1,142 @@ +/* + * http://linux.m2osw.com/c-implementation-udp-clientserver + * + * UDPSender.cpp + * + * Created on: 29.06.2016 + * Author: Tobias Frust + */ + + // ========================= CLIENT ========================= + + /** \brief Initialize a UDP client object. + * + * This function initializes the UDP client object using the address and the + * port as specified. + * + * The port is expected to be a host side port number (i.e. 59200). + * + * The \p addr parameter is a textual address. It may be an IPv4 or IPv6 + * address and it can represent a host name or an address defined with + * just numbers. If the address cannot be resolved then an error occurs + * and constructor throws. + * + * \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. + * + * \exception udp_client_server_runtime_error + * The server could not be initialized properly. Either the address cannot be + * resolved, the port is incompatible or not available, or the socket could + * not be created. + * + * \param[in] addr The address to convert to a numeric IP. + * \param[in] port The port number. + */ + +#include "UDPClient.h" + +#include <string.h> +#include <unistd.h> + +#ifndef SOCK_CLOEXEC +#define SOCK_CLOEXEC 0 +#endif + + UDPClient::UDPClient(const std::string& addr, int port) + : f_port(port) + , f_addr(addr){ + printf("Creating client %d\n", f_port); + 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: \"" + 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 socket for: \"" + addr + ":" + decimal_port + "\"").c_str()); + } + printf("Created client %d\n", f_port); + } + + /** \brief Clean up the UDP client object. + * + * This function frees the address information structure and close the socket + * before returning. + */ + UDPClient::~UDPClient() + { + freeaddrinfo(f_addrinfo); + close(f_socket); + } + + /** \brief Retrieve a copy of the socket identifier. + * + * This function return the socket identifier as returned by the socket() + * function. This can be used to change some flags. + * + * \return The socket used by this UDP client. + */ + int UDPClient::get_socket() const { + return f_socket; + } + + /** \brief Retrieve the port used by this UDP client. + * + * This function returns the port used by this UDP client. The port is + * defined as an integer, host side. + * + * \return The port as expected in a host integer. + */ + int UDPClient::get_port() const { + return f_port; + } + + /** \brief Retrieve a copy of the address. + * + * This function returns a copy of the address as it was specified in the + * constructor. This does not return a canonalized version of the address. + * + * The address cannot be modified. If you need to send data on a different + * address, create a new UDP client. + * + * \return A string with a copy of the constructor input address. + */ + std::string UDPClient::get_addr() const { + return f_addr; + } + + /** \brief Send a message through this UDP client. + * + * This function sends \p msg through the UDP client socket. The function + * cannot be used to change the destination as it was defined when creating + * the udp_client object. + * + * The size must be small enough for the message to fit. In most cases we + * use these in Snap! to send very small signals (i.e. 4 bytes commands.) + * Any data we would want to share remains in the Cassandra database so + * that way we can avoid losing it because of a UDP message. + * + * \param[in] msg The message to send. + * \param[in] size The number of bytes representing this message. + * + * \return -1 if an error occurs, otherwise the number of bytes sent. errno + * is set accordingly on error. + */ + int UDPClient::send(const char *msg, std::size_t size){ + return sendto(f_socket, msg, size, 0, f_addrinfo->ai_addr, f_addrinfo->ai_addrlen); + } diff --git a/src/UDPClient/UDPClient.h b/src/UDPClient/UDPClient.h new file mode 100644 index 0000000..f6cf0d6 --- /dev/null +++ b/src/UDPClient/UDPClient.h @@ -0,0 +1,44 @@ +/* + * http://linux.m2osw.com/c-implementation-udp-clientserver + * + * UDPSender.h + * + * Created on: 29.06.2016 + * Author: Tobias Frust + */ + +#ifndef UDPCLIENT_H_ +#define UDPCLIENT_H_ + +#include <sys/types.h> +#include <sys/socket.h> +#include <netdb.h> +#include <stdexcept> +#include <cstring> + +class udp_client_server_runtime_error : public std::runtime_error +{ +public: + udp_client_server_runtime_error(const char *w) : std::runtime_error(w) {} +}; + + +class UDPClient { +public: + UDPClient(const std::string& addr, int port); + ~UDPClient(); + + int get_socket() const; + int get_port() const; + std::string get_addr() const; + + int send(const char *msg, size_t size); + +private: + int f_socket; + int f_port; + std::string f_addr; + struct addrinfo * f_addrinfo; +}; + +#endif /* UDPCLIENT_H_ */ |