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 <string.h>
  21 #include <errno.h>
  22
  23 #include "net.h"
  24 #include "util.h"
  25
  26 static int listen_socket = -1;
  27 static struct event listen_evq;
  28 static evh accept_handler;
  29 static usec main_deadline = 0;
  30 static int brakes_are_on = 1, after_startup = 0;
  31
  32 int
  33 make_server_socket(char *host, char *port)
  34 {
  35     int fd = -1, flags, r;
  36     struct linger linger = {0, 0};
  37     struct addrinfo *airoot, *ai, hints;
  38
  39     memset(&hints, 0, sizeof(hints));
  40     hints.ai_family = PF_UNSPEC;
  41     hints.ai_socktype = SOCK_STREAM;
  42     hints.ai_flags = AI_PASSIVE;
  43     r = getaddrinfo(host, port, &hints, &airoot);
  44     if (r == -1)
  45       return twarn("getaddrinfo()"), -1;
  46
  47     for(ai = airoot; ai; ai = ai->ai_next) {
  48       fd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
  49       if (fd == -1) {
  50         twarn("socket()");
  51         continue;
  52       }
  53
  54       flags = fcntl(fd, F_GETFL, 0);
  55       if (flags < 0) {
  56         twarn("getting flags");
  57         close(fd);
  58         continue;
  59       }
  60
  61       r = fcntl(fd, F_SETFL, flags | O_NONBLOCK);
  62       if (r == -1) {
  63         twarn("setting O_NONBLOCK");
  64         close(fd);
  65         continue;
  66       }
  67
  68       flags = 1;
  69       setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &flags, sizeof flags);
  70       setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, &flags, sizeof flags);
  71       setsockopt(fd, SOL_SOCKET, SO_LINGER,   &linger, sizeof linger);
  72       setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &flags, sizeof flags);
  73
  74       r = bind(fd, ai->ai_addr, ai->ai_addrlen);
  75       if (r == -1) {
  76         twarn("bind()");
  77         close(fd);
  78         continue;
  79       }
  80
  81       r = listen(fd, 1024);
  82       if (r == -1) {
  83         twarn("listen()");
  84         close(fd);
  85         continue;
  86       }
  87
  88       break;
  89     }
  90
  91     freeaddrinfo(airoot);
  92
  93     if(ai == NULL)
  94       fd = -1;
  95
  96     return listen_socket = fd;
  97 }
  98
  99 void
 100 brake()
 101 {
 102     int r;
 103
 104     if (brakes_are_on) return;
 105     brakes_are_on = 1;
 106     twarnx("too many connections; putting on the brakes");
 107
 108     r = event_del(&listen_evq);
 109     if (r == -1) twarn("event_del()");
 110
 111     r = listen(listen_socket, 0);
 112     if (r == -1) twarn("listen()");
 113 }
 114
 115 void
 116 unbrake(evh h)
 117 {
 118     int r;
 119
 120     if (!brakes_are_on) return;
 121     brakes_are_on = 0;
 122     if (after_startup) twarnx("releasing the brakes");
 123     after_startup = 1;
 124
 125     accept_handler = h ? : accept_handler;
 126     event_set(&listen_evq, listen_socket, EV_READ | EV_PERSIST,
 127               accept_handler, &listen_evq);
 128
 129     set_main_timeout(main_deadline);
 130
 131     r = listen(listen_socket, 1024);
 132     if (r == -1) twarn("listen()");
 133 }
 134
 135 void
 136 set_main_timeout(usec deadline_at)
 137 {
 138     int r;
 139     struct timeval tv;
 140     usec now = now_usec();
 141
 142     main_deadline = deadline_at;
 143
 144     /* If there is no deadline, we just wait for a long while.
 145      * This works around a bug in libevent or kqueue on Mac OS X. */
 146     if (!deadline_at) deadline_at = now + 100 * SECOND;
 147
 148     timeval_from_usec(&tv, (deadline_at > now) ? deadline_at - now : 1);
 149
 150     r = event_add(&listen_evq, &tv);
 151     if (r == -1) twarn("event_add()");
 152 }