net.c

   1 /* net.c - stupid boilerplate shit that I shouldn't have to write */
   2
   3 /* Copyright (C) 2007 Keith Rarick and Philotic Inc.
   4
   5  * This program is free software: you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation, either version 3 of the License, or
   8  * (at your option) any later version.
   9
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include <stdio.h>
  20 #include <errno.h>
  21
  22 #include "net.h"
  23 #include "util.h"
  24
  25 static int listen_socket = -1;
  26 static struct event listen_evq;
  27 static evh accept_handler;
  28 static time_t main_deadline = 0;
  29 static int brakes_are_on = 1, after_startup = 0;
  30
  31 int
  32 make_server_socket(struct in_addr host_addr, int port)
  33 {
  34     int fd, flags, r;
  35     struct linger linger = {0, 0};
  36     struct sockaddr_in addr = {}; /* initialize to 0 */
  37
  38     fd = socket(AF_INET, SOCK_STREAM, 0);
  39     if (fd == -1) return twarn("socket()"), -1;
  40
  41     flags = fcntl(fd, F_GETFL, 0);
  42     if (flags < 0) return twarn("getting flags"), close(fd), -1;
  43
  44     r = fcntl(fd, F_SETFL, flags | O_NONBLOCK);
  45     if (r == -1) return twarn("setting O_NONBLOCK"), close(fd), -1;
  46
  47     flags = 1;
  48     setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &flags, sizeof flags);
  49     setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, &flags, sizeof flags);
  50     setsockopt(fd, SOL_SOCKET, SO_LINGER,   &linger, sizeof linger);
  51     setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &flags, sizeof flags);
  52
  53     addr.sin_family = AF_INET;
  54     addr.sin_port = htons(port);
  55     addr.sin_addr = host_addr;
  56     r = bind(fd, (struct sockaddr *) &addr, sizeof addr);
  57     if (r == -1) return twarn("bind()"), close(fd), -1;
  58
  59     r = listen(fd, 1024);
  60     if (r == -1) return twarn("listen()"), close(fd), -1;
  61
  62     return listen_socket = fd;
  63 }
  64
  65 void
  66 brake()
  67 {
  68     int r;
  69
  70     if (brakes_are_on) return;
  71     brakes_are_on = 1;
  72     twarnx("too many connections; putting on the brakes");
  73
  74     r = event_del(&listen_evq);
  75     if (r == -1) twarn("event_del()");
  76
  77     r = listen(listen_socket, 0);
  78     if (r == -1) twarn("listen()");
  79 }
  80
  81 void
  82 unbrake(evh h)
  83 {
  84     int r;
  85
  86     if (!brakes_are_on) return;
  87     brakes_are_on = 0;
  88     if (after_startup) twarnx("releasing the brakes");
  89     after_startup = 1;
  90
  91     accept_handler = h ? : accept_handler;
  92     event_set(&listen_evq, listen_socket, EV_READ | EV_PERSIST,
  93               accept_handler, &listen_evq);
  94
  95     set_main_timeout(main_deadline);
  96
  97     r = listen(listen_socket, 1024);
  98     if (r == -1) twarn("listen()");
  99 }
 100
 101 void
 102 set_main_timeout(time_t deadline)
 103 {
 104     int r;
 105     struct timeval tv = {deadline - time(NULL), 0};
 106
 107     main_deadline = deadline;
 108     r = event_add(&listen_evq, deadline ? &tv : NULL);
 109     if (r == -1) twarn("event_add()");
 110 }