source: trunk/FACT++/src/DimSetup.cc@ 19713

Last change on this file since 19713 was 19420, checked in by tbretz, 6 years ago
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File size: 5.4 KB
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1// **************************************************************************
2/** @namespace Dim
3
4@brief Namespace to host some global Dim helper functions
5
6*/
7// **************************************************************************
8#include "Dim.h"
9
10/*
11#include <netdb.h>
12#include <sys/types.h>
13#include <sys/socket.h>
14#include <arpa/inet.h>
15*/
16#include <boost/asio.hpp>
17
18#include <iostream>
19
20using namespace std;
21
22// --------------------------------------------------------------------------
23//
24//! Tries to determine the local IP address with which we will connect
25//! to the DIM dns.
26//!
27//! The local IP address is necessary because in some circumstances
28//! Dim needs the IP address of the connecting machine (DIM_HOST_NODE)
29//! for the clients to correctly connect to them. So what we would
30//! need is the IP address over which the machine is reachable from
31//! the client. Unfortunately, we have no access to the client
32//! connection, hence, we have to find the best guess of an address
33//! which is not our own machine and hope it is routed over the
34//! standard ethernet interface over which other clients will connect.
35//!
36//! To not send random packages over the network we use a local
37//! IP address. To make sure it is something which leaves the network
38//! card and is not just our machine, we can use a broadcast address.
39//! Consequently, the deafult has been chosen to be "192.168.0.255"
40//!
41//! @param dns
42//! Address of the Dim-dns
43//!
44//! @returns
45//! The IP Address through which the connection to the DNS will
46//! take place.
47//!
48//! @todo
49//! Implement a --host command line option (just in case)
50//!
51string Dim::GetLocalIp(const string &dns)
52{
53 using namespace boost::asio;
54 using namespace boost::asio::ip;
55
56 cout << "Trying to resolve local IP address..." << endl;
57
58 boost::system::error_code ec;
59
60 boost::asio::io_service io_service;
61
62 udp::socket socket(io_service);
63
64 udp::resolver resolver(io_service);
65 udp::resolver::query query(dns, "0");
66 udp::resolver::iterator iterator = resolver.resolve(query, ec);
67 if (ec)
68 {
69 //cout << "WARNING - Failure in name-resolution of '" << dns << ":0': ";
70 cout << "WARNING - Could not resolve local ip address: ";
71 cout << ec.message() << " (" << ec << ")" << endl;
72 return dns;
73 }
74
75 for (; iterator != udp::resolver::iterator(); ++iterator)
76 {
77 udp::endpoint endpoint = *iterator;
78 socket.connect(endpoint, ec);
79 if (ec)
80 {
81 cout << "WARNING - Could not resolve local ip address: ";
82 cout << ec.message() << " (" << ec << ")" << endl;
83 continue;
84 }
85
86 const string addr = socket.local_endpoint().address().to_v4().to_string();
87 return addr;
88 }
89
90 return "localhost";
91
92/*
93 struct addrinfo hints, *servinfo, *p;
94
95 memset(&hints, 0, sizeof hints);
96 hints.ai_family = AF_INET; //AF_UNSPEC; // use AF_INET6 to force IPv6
97 hints.ai_socktype = SOCK_STREAM;
98
99 int rv;
100 if ((rv = getaddrinfo(dns.c_str(), NULL, &hints, &servinfo)) != 0)
101 {
102 cout << "WARNING - getaddrinfo: " << gai_strerror(rv) << endl;
103 return dns;
104 }
105
106 // loop through all the results and connect to the first we can
107 for (p=servinfo; p; p=p->ai_next)
108 {
109 const int sock = socket(AF_INET, SOCK_DGRAM, 0);
110 if (sock==-1)
111 continue;
112
113 if (connect(sock, p->ai_addr, p->ai_addrlen)==-1)
114 {
115 cout << "WARNING - connect: " << strerror(errno) << endl;
116 close(sock);
117 continue;
118 }
119
120 sockaddr_in name;
121 socklen_t namelen = sizeof(name);
122 if (getsockname(sock, (sockaddr*)&name, &namelen)==-1)
123 {
124 cout << "WARNING - getsockname: " << strerror(errno) << endl;
125 close(sock);
126 continue;
127 }
128
129 char buffer[16];
130 if (!inet_ntop(AF_INET, &name.sin_addr, buffer, 16))
131 {
132 cout << "WARNING - inet_ntop: " << strerror(errno) << endl;
133 close(sock);
134 continue;
135 }
136
137 close(sock);
138
139 freeaddrinfo(servinfo); // all done with this structure
140
141 cout << "DIM_HOST_NODE=" << buffer << endl;
142 return buffer;
143 }
144
145 freeaddrinfo(servinfo); // all done with this structure
146
147 return dns;
148*/
149}
150
151// --------------------------------------------------------------------------
152//
153//! Set the environment variable DIM_DNS_NODE to the given string and
154//! DIM_HOST_NODE to the IP-address through which this machine connects
155//! to the dns.
156//!
157//! @param dns
158//! Address of the Dim-dns
159//!
160void Dim::Setup(const std::string &dns, const std::string &host, const uint16_t &port)
161{
162 if (dns.empty())
163 {
164 setenv("DIM_DNS_NODE", "...", 1);
165 //unsetenv("DIM_DNS_NODE");
166 //unsetenv("DIM_HOST_NODE");
167 return;
168 }
169
170 const string loc = host.empty() ? Dim::GetLocalIp(dns.c_str()) : host;
171
172 setenv("DIM_DNS_NODE", dns.c_str(), 1);
173 setenv("DIM_HOST_NODE", loc.c_str(), 1);
174 if (port>0)
175 setenv("DIM_DNS_PORT", to_string(port).c_str(), 1);
176
177 cout << "Setting DIM_DNS_NODE =" << dns;
178 if (port>0)
179 cout << ':' << port;
180 cout << "\nSetting DIM_HOST_NODE=" << loc << endl;
181}
182
183extern "C"
184{
185 const char *GetLocalIp()
186 {
187 static string rc;
188 rc = Dim::GetLocalIp();
189 cout << "Setting DIM_HOST_NODE=" << rc << endl;
190 return rc.c_str();
191 }
192}
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