summaryrefslogtreecommitdiff
path: root/src/network/socket_handler.cpp
blob: d774927d6d1e509930e546ddfa8547e97e5e59ac (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
#include <network/socket_handler.hpp>

#include <utils/scopeguard.hpp>
#include <network/poller.hpp>

#include <logger/logger.hpp>
#include <sys/socket.h>
#include <sys/types.h>
#include <stdexcept>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <cstring>
#include <fcntl.h>
#include <netdb.h>
#include <stdio.h>

#include <iostream>

#ifndef UIO_FASTIOV
# define UIO_FASTIOV 8
#endif

SocketHandler::SocketHandler():
  poller(nullptr),
  connected(false),
  connecting(false)
{
  this->init_socket();
}

void SocketHandler::init_socket()
{
  if ((this->socket = ::socket(AF_INET, SOCK_STREAM, 0)) == -1)
    throw std::runtime_error("Could not create socket");
  int optval = 1;
  if (::setsockopt(this->socket, SOL_SOCKET, SO_KEEPALIVE, &optval, sizeof(optval)) == -1)
    log_warning("Failed to enable TCP keepalive on socket: " << strerror(errno));
  // Set the socket on non-blocking mode.  This is useful to receive a EAGAIN
  // error when connect() would block, to not block the whole process if a
  // remote is not responsive.
  const int existing_flags = ::fcntl(this->socket, F_GETFL, 0);
  if ((existing_flags == -1) ||
      (::fcntl(this->socket, F_SETFL, existing_flags | O_NONBLOCK) == -1))
    throw std::runtime_error(std::string("Could not initialize socket: ") + strerror(errno));
}

void SocketHandler::connect(const std::string& address, const std::string& port)
{
  this->address = address;
  this->port = port;

  utils::ScopeGuard sg;

  struct addrinfo* addr_res;

  if (!this->connecting)
    {
      log_info("Trying to connect to " << address << ":" << port);
      // Get the addrinfo from getaddrinfo, only if this is the first call
      // of this function.
      struct addrinfo hints;
      memset(&hints, 0, sizeof(struct addrinfo));
      hints.ai_flags = 0;
      hints.ai_family = AF_INET;
      hints.ai_socktype = SOCK_STREAM;
      hints.ai_protocol = 0;

      const int res = ::getaddrinfo(address.c_str(), port.c_str(), &hints, &addr_res);

      if (res != 0)
        {
          log_warning(std::string("getaddrinfo failed: ") + gai_strerror(res));
          this->close();
          this->on_connection_failed(gai_strerror(res));
          return ;
        }
      // Make sure the alloced structure is always freed at the end of the
      // function
      sg.add_callback([&addr_res](){ freeaddrinfo(addr_res); });
    }
  else
    {
      // This function is called again, use the saved addrinfo structure,
      // instead of re-doing the whole getaddrinfo process.  We insert only
      // the meaningful values in the structure, and indicate that these are
      // the only possible values with ai_next = NULL.
      addr_res = (struct addrinfo*)malloc(sizeof(struct addrinfo));
      if (!addr_res)
        {
          this->close();
          this->on_connection_failed("memory error");
          return ;
        }
      sg.add_callback([&addr_res](){ free(addr_res); });
      addr_res->ai_next = NULL;
      addr_res->ai_addr = &this->ai_addr;
      addr_res->ai_addrlen = this->ai_addrlen;
    }
  this->connecting = true;

  for (struct addrinfo* rp = addr_res; rp; rp = rp->ai_next)
    {
      if (::connect(this->socket, rp->ai_addr, rp->ai_addrlen) == 0
          || errno == EISCONN)
        {
          log_info("Connection success.");
          this->connected = true;
          this->connecting = false;
          this->on_connected();
          return ;
        }
      else if (errno == EINPROGRESS || errno == EALREADY)
        {   // retry this process later, when the socket
            // is ready to be written on.
          log_debug("Need to retry connecting later..." << strerror(errno));
          this->poller->watch_send_events(this);
          // Save the addrinfo structure, to use it on the next call
          this->ai_addrlen = rp->ai_addrlen;
          memcpy(&this->ai_addr, rp->ai_addr, this->ai_addrlen);
          return ;
        }
      log_info("Connection failed:" << strerror(errno));
    }
  log_error("All connection attempts failed.");
  this->close();
  this->on_connection_failed(strerror(errno));
  return ;
}

void SocketHandler::connect()
{
  this->connect(this->address, this->port);
}

void SocketHandler::set_poller(Poller* poller)
{
  this->poller = poller;
}

void SocketHandler::on_recv()
{
  static constexpr size_t buf_size = 4096;
  char buf[buf_size];
  void* recv_buf = this->get_receive_buffer(buf_size);

  if (recv_buf == nullptr)
    recv_buf = buf;

  ssize_t size = ::recv(this->socket, recv_buf, buf_size, 0);
  if (0 == size)
    {
      this->on_connection_close();
      this->close();
    }
  else if (-1 == static_cast<ssize_t>(size))
    {
      log_warning("Error while reading from socket: " << strerror(errno));
      this->on_connection_close();
      this->close();
    }
  else
    {
      if (buf == recv_buf)
        {
          // data needs to be placed in the in_buf string, because no buffer
          // was provided to receive that data directly. The in_buf buffer
          // will be handled in parse_in_buffer()
          this->in_buf += std::string(buf, size);
        }
      this->parse_in_buffer(size);
    }
}

void SocketHandler::on_send()
{
  struct iovec msg_iov[UIO_FASTIOV] = {};
  struct msghdr msg{nullptr, 0,
      msg_iov,
      0, nullptr, 0, 0};
  for (std::string& s: this->out_buf)
    {
      // unconsting the content of s is ok, sendmsg will never modify it
      msg_iov[msg.msg_iovlen].iov_base = const_cast<char*>(s.data());
      msg_iov[msg.msg_iovlen].iov_len = s.size();
      if (++msg.msg_iovlen == UIO_FASTIOV)
        break;
    }
  ssize_t res = ::sendmsg(this->socket, &msg, MSG_NOSIGNAL);
  if (res < 0)
    {
      log_error("sendmsg failed: " << strerror(errno));
      this->on_connection_close();
      this->close();
    }
  else
    {
      // remove all the strings that were successfully sent.
      for (auto it = this->out_buf.begin();
           it != this->out_buf.end();)
        {
          if (static_cast<size_t>(res) >= (*it).size())
            {
              res -= (*it).size();
              it = this->out_buf.erase(it);
            }
          else
            {
              // If one string has partially been sent, we use substr to
              // crop it
              if (res > 0)
                (*it) = (*it).substr(res, std::string::npos);
              break;
            }
        }
      if (this->out_buf.empty())
        this->poller->stop_watching_send_events(this);
    }
}

void SocketHandler::close()
{
  this->connected = false;
  this->connecting = false;
  this->poller->remove_socket_handler(this->get_socket());
  ::close(this->socket);
  // recreate the socket for a potential future usage
  this->init_socket();
}

socket_t SocketHandler::get_socket() const
{
  return this->socket;
}

void SocketHandler::send_data(std::string&& data)
{
  if (data.empty())
    return ;
  this->out_buf.emplace_back(std::move(data));
  this->poller->watch_send_events(this);
}

bool SocketHandler::is_connected() const
{
  return this->connected;
}

bool SocketHandler::is_connecting() const
{
  return this->connecting;
}

void* SocketHandler::get_receive_buffer(const size_t) const
{
  return nullptr;
}