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proxy.c

/*
 * Proxy variables and functions.
 *
 * Copyright 2000-2007 Willy Tarreau <w@1wt.eu>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 *
 */

#include <fcntl.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/stat.h>

#include <common/defaults.h>
#include <common/compat.h>
#include <common/config.h>
#include <common/memory.h>
#include <common/time.h>

#include <types/global.h>
#include <types/polling.h>

#include <proto/client.h>
#include <proto/fd.h>
#include <proto/log.h>
#include <proto/proxy.h>


int listeners;    /* # of listeners */
struct proxy *proxy  = NULL;  /* list of all existing proxies */

/*
 * This function returns a string containing the type of the proxy in a format
 * suitable for error messages, from its capabilities.
 */
const char *proxy_type_str(struct proxy *proxy)
{
      int cap = proxy->cap;
      if ((cap & PR_CAP_LISTEN) == PR_CAP_LISTEN)
            return "listener";
      else if (cap & PR_CAP_FE)
            return "frontend";
      else if (cap & PR_CAP_BE)
            return "backend";
      else if (cap & PR_CAP_RS)
            return "ruleset";
      else
            return "proxy";
}


/*
 * This function creates all proxy sockets. It should be done very early,
 * typically before privileges are dropped. The sockets will be registered
 * but not added to any fd_set, in order not to loose them across the fork().
 * The proxies also start in IDLE state, meaning that it will be
 * maintain_proxies that will finally complete their loading.
 *
 * Its return value is composed from ERR_NONE, ERR_RETRYABLE and ERR_FATAL.
 * Retryable errors will only be printed if <verbose> is not zero.
 */
int start_proxies(int verbose)
{
      struct proxy *curproxy;
      struct listener *listener;
      int err = ERR_NONE;
      int fd, pxerr;

      for (curproxy = proxy; curproxy != NULL; curproxy = curproxy->next) {
            if (curproxy->state != PR_STNEW)
                  continue; /* already initialized */

            pxerr = 0;
            for (listener = curproxy->listen; listener != NULL; listener = listener->next) {
                  if (listener->fd != -1)
                        continue; /* already initialized */

                  if ((fd = socket(listener->addr.ss_family, SOCK_STREAM, IPPROTO_TCP)) == -1) {
                        if (verbose)
                              Alert("cannot create listening socket for proxy %s. Aborting.\n",
                                    curproxy->id);
                        err |= ERR_RETRYABLE;
                        pxerr |= 1;
                        continue;
                  }
      
                  if (fd >= global.maxsock) {
                        Alert("socket(): not enough free sockets for proxy %s. Raise -n argument. Aborting.\n",
                              curproxy->id);
                        close(fd);
                        err |= ERR_FATAL;
                        pxerr |= 1;
                        break;
                  }

                  if ((fcntl(fd, F_SETFL, O_NONBLOCK) == -1) ||
                      (setsockopt(fd, IPPROTO_TCP, TCP_NODELAY,
                              (char *) &one, sizeof(one)) == -1)) {
                        Alert("cannot make socket non-blocking for proxy %s. Aborting.\n",
                              curproxy->id);
                        close(fd);
                        err |= ERR_FATAL;
                        pxerr |= 1;
                        break;
                  }

                  if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (char *) &one, sizeof(one)) == -1) {
                        Alert("cannot do so_reuseaddr for proxy %s. Continuing.\n",
                              curproxy->id);
                  }
      
#ifdef SO_REUSEPORT
                  /* OpenBSD supports this. As it's present in old libc versions of Linux,
                   * it might return an error that we will silently ignore.
                   */
                  setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, (char *) &one, sizeof(one));
#endif
                  if (bind(fd,
                         (struct sockaddr *)&listener->addr,
                         listener->addr.ss_family == AF_INET6 ?
                         sizeof(struct sockaddr_in6) :
                         sizeof(struct sockaddr_in)) == -1) {
                        if (verbose)
                              Alert("cannot bind socket for proxy %s. Aborting.\n",
                                    curproxy->id);
                        close(fd);
                        err |= ERR_RETRYABLE;
                        pxerr |= 1;
                        continue;
                  }
      
                  if (listen(fd, curproxy->maxconn) == -1) {
                        if (verbose)
                              Alert("cannot listen to socket for proxy %s. Aborting.\n",
                                    curproxy->id);
                        close(fd);
                        err |= ERR_RETRYABLE;
                        pxerr |= 1;
                        continue;
                  }
      
                  /* the socket is ready */
                  listener->fd = fd;

                  /* the function for the accept() event */
                  fd_insert(fd);
                  fdtab[fd].cb[DIR_RD].f  = &event_accept;
                  fdtab[fd].cb[DIR_WR].f = NULL; /* never called */
                  fdtab[fd].cb[DIR_RD].b = fdtab[fd].cb[DIR_WR].b = NULL;
                  fdtab[fd].owner = (struct task *)curproxy; /* reference the proxy instead of a task */
                  fdtab[fd].state = FD_STLISTEN;
                  fdtab[fd].ev = 0;
                  listeners++;
            }

            if (!pxerr) {
                  curproxy->state = PR_STIDLE;
                  send_log(curproxy, LOG_NOTICE, "Proxy %s started.\n", curproxy->id);
            }
      }

      return err;
}


/*
 * this function enables proxies when there are enough free sessions,
 * or stops them when the table is full. It is designed to be called from the
 * select_loop(). It returns the date of next expiration event during stop
 * time, ETERNITY otherwise.
 */
void maintain_proxies(struct timeval *next)
{
      struct proxy *p;
      struct listener *l;

      p = proxy;
      tv_eternity(next);

      /* if there are enough free sessions, we'll activate proxies */
      if (actconn < global.maxconn) {
            while (p) {
                  if (p->feconn < p->maxconn) {
                        if (p->state == PR_STIDLE) {
                              for (l = p->listen; l != NULL; l = l->next) {
                                    EV_FD_SET(l->fd, DIR_RD);
                              }
                              p->state = PR_STRUN;
                        }
                  }
                  else {
                        if (p->state == PR_STRUN) {
                              for (l = p->listen; l != NULL; l = l->next) {
                                    EV_FD_CLR(l->fd, DIR_RD);
                              }
                              p->state = PR_STIDLE;
                        }
                  }
                  p = p->next;
            }
      }
      else {  /* block all proxies */
            while (p) {
                  if (p->state == PR_STRUN) {
                        for (l = p->listen; l != NULL; l = l->next) {
                              EV_FD_CLR(l->fd, DIR_RD);
                        }
                        p->state = PR_STIDLE;
                  }
                  p = p->next;
            }
      }

      if (stopping) {
            p = proxy;
            while (p) {
                  if (p->state != PR_STSTOPPED) {
                        int t;
                        t = tv_ms_remain2(&now, &p->stop_time);
                        if (t == 0) {
                              Warning("Proxy %s stopped.\n", p->id);
                              send_log(p, LOG_WARNING, "Proxy %s stopped.\n", p->id);

                              for (l = p->listen; l != NULL; l = l->next) {
                                    fd_delete(l->fd);
                                    listeners--;
                              }
                              p->state = PR_STSTOPPED;
                              /* try to free more memory */
                              pool_gc2();
                        }
                        else {
                              tv_bound(next, &p->stop_time);
                        }
                  }
                  p = p->next;
            }
      }
      return;
}


/*
 * this function disables health-check servers so that the process will quickly be ignored
 * by load balancers. Note that if a proxy was already in the PAUSED state, then its grace
 * time will not be used since it would already not listen anymore to the socket.
 */
void soft_stop(void)
{
      struct proxy *p;

      stopping = 1;
      p = proxy;
      tv_now(&now); /* else, the old time before select will be used */
      while (p) {
            if (p->state != PR_STSTOPPED) {
                  Warning("Stopping proxy %s in %d ms.\n", p->id, p->grace);
                  send_log(p, LOG_WARNING, "Stopping proxy %s in %d ms.\n", p->id, p->grace);
                  tv_ms_add(&p->stop_time, &now, p->grace);
            }
            p = p->next;
      }
}


/*
 * Linux unbinds the listen socket after a SHUT_RD, and ignores SHUT_WR.
 * Solaris refuses either shutdown().
 * OpenBSD ignores SHUT_RD but closes upon SHUT_WR and refuses to rebind.
 * So a common validation path involves SHUT_WR && listen && SHUT_RD.
 * If disabling at least one listener returns an error, then the proxy
 * state is set to PR_STERROR because we don't know how to resume from this.
 */
void pause_proxy(struct proxy *p)
{
      struct listener *l;
      for (l = p->listen; l != NULL; l = l->next) {
            if (shutdown(l->fd, SHUT_WR) == 0 &&
                listen(l->fd, p->maxconn) == 0 &&
                shutdown(l->fd, SHUT_RD) == 0) {
                  EV_FD_CLR(l->fd, DIR_RD);
                  if (p->state != PR_STERROR)
                        p->state = PR_STPAUSED;
            }
            else
                  p->state = PR_STERROR;
      }
}

/*
 * This function temporarily disables listening so that another new instance
 * can start listening. It is designed to be called upon reception of a
 * SIGTTOU, after which either a SIGUSR1 can be sent to completely stop
 * the proxy, or a SIGTTIN can be sent to listen again.
 */
void pause_proxies(void)
{
      int err;
      struct proxy *p;

      err = 0;
      p = proxy;
      tv_now(&now); /* else, the old time before select will be used */
      while (p) {
            if (p->state != PR_STERROR &&
                p->state != PR_STSTOPPED &&
                p->state != PR_STPAUSED) {
                  Warning("Pausing proxy %s.\n", p->id);
                  send_log(p, LOG_WARNING, "Pausing proxy %s.\n", p->id);
                  pause_proxy(p);
                  if (p->state != PR_STPAUSED) {
                        err |= 1;
                        Warning("Proxy %s failed to enter pause mode.\n", p->id);
                        send_log(p, LOG_WARNING, "Proxy %s failed to enter pause mode.\n", p->id);
                  }
            }
            p = p->next;
      }
      if (err) {
            Warning("Some proxies refused to pause, performing soft stop now.\n");
            send_log(p, LOG_WARNING, "Some proxies refused to pause, performing soft stop now.\n");
            soft_stop();
      }
}


/*
 * This function reactivates listening. This can be used after a call to
 * sig_pause(), for example when a new instance has failed starting up.
 * It is designed to be called upon reception of a SIGTTIN.
 */
void listen_proxies(void)
{
      struct proxy *p;
      struct listener *l;

      p = proxy;
      tv_now(&now); /* else, the old time before select will be used */
      while (p) {
            if (p->state == PR_STPAUSED) {
                  Warning("Enabling proxy %s.\n", p->id);
                  send_log(p, LOG_WARNING, "Enabling proxy %s.\n", p->id);

                  for (l = p->listen; l != NULL; l = l->next) {
                        if (listen(l->fd, p->maxconn) == 0) {
                              if (actconn < global.maxconn && p->feconn < p->maxconn) {
                                    EV_FD_SET(l->fd, DIR_RD);
                                    p->state = PR_STRUN;
                              }
                              else
                                    p->state = PR_STIDLE;
                        } else {
                              int port;

                              if (l->addr.ss_family == AF_INET6)
                                    port = ntohs(((struct sockaddr_in6 *)(&l->addr))->sin6_port);
                              else
                                    port = ntohs(((struct sockaddr_in *)(&l->addr))->sin_port);

                              Warning("Port %d busy while trying to enable proxy %s.\n",
                                    port, p->id);
                              send_log(p, LOG_WARNING, "Port %d busy while trying to enable proxy %s.\n",
                                     port, p->id);
                              /* Another port might have been enabled. Let's stop everything. */
                              pause_proxy(p);
                              break;
                        }
                  }
            }
            p = p->next;
      }
}


/*
 * Local variables:
 *  c-indent-level: 8
 *  c-basic-offset: 8
 * End:
 */

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