source: vendor/current/ctdb/tcp/tcp_connect.c

/* 
   ctdb over TCP

   Copyright (C) Andrew Tridgell  2006
   Copyright (C) Ronnie Sahlberg  2008

   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 3 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, see <http://www.gnu.org/licenses/>.
*/

#include "replace.h"
#include "system/network.h"
#include "system/filesys.h"

#include <talloc.h>
#include <tevent.h>

#include "lib/util/debug.h"
#include "lib/util/time.h"

#include "ctdb_private.h"

#include "common/system.h"
#include "common/common.h"
#include "common/logging.h"

#include "ctdb_tcp.h"

/*
  stop any connecting (established or pending) to a node
 */
void ctdb_tcp_stop_connection(struct ctdb_node *node)
{
        struct ctdb_tcp_node *tnode = talloc_get_type(
                node->private_data, struct ctdb_tcp_node);
        
        ctdb_queue_set_fd(tnode->out_queue, -1);
        talloc_free(tnode->connect_te);
        talloc_free(tnode->connect_fde);
        tnode->connect_fde = NULL;
        tnode->connect_te = NULL;
        if (tnode->fd != -1) {
                close(tnode->fd);
                tnode->fd = -1;
        }
}


/*
  called when a complete packet has come in - should not happen on this socket
  unless the other side closes the connection with RST or FIN
 */
void ctdb_tcp_tnode_cb(uint8_t *data, size_t cnt, void *private_data)
{
        struct ctdb_node *node = talloc_get_type(private_data, struct ctdb_node);
        struct ctdb_tcp_node *tnode = talloc_get_type(
                node->private_data, struct ctdb_tcp_node);

        if (data == NULL) {
                node->ctdb->upcalls->node_dead(node);
        }

        ctdb_tcp_stop_connection(node);
        tnode->connect_te = tevent_add_timer(node->ctdb->ev, tnode,
                                             timeval_current_ofs(3, 0),
                                             ctdb_tcp_node_connect, node);
}

/*
  called when socket becomes writeable on connect
*/
static void ctdb_node_connect_write(struct tevent_context *ev,
                                    struct tevent_fd *fde,
                                    uint16_t flags, void *private_data)
{
        struct ctdb_node *node = talloc_get_type(private_data,
                                                 struct ctdb_node);
        struct ctdb_tcp_node *tnode = talloc_get_type(node->private_data,
                                                      struct ctdb_tcp_node);
        struct ctdb_context *ctdb = node->ctdb;
        int error = 0;
        socklen_t len = sizeof(error);
        int one = 1;

        talloc_free(tnode->connect_te);
        tnode->connect_te = NULL;

        if (getsockopt(tnode->fd, SOL_SOCKET, SO_ERROR, &error, &len) != 0 ||
            error != 0) {
                ctdb_tcp_stop_connection(node);
                tnode->connect_te = tevent_add_timer(ctdb->ev, tnode,
                                                    timeval_current_ofs(1, 0),
                                                    ctdb_tcp_node_connect, node);
                return;
        }

        talloc_free(tnode->connect_fde);
        tnode->connect_fde = NULL;

        if (setsockopt(tnode->fd,IPPROTO_TCP,TCP_NODELAY,(char *)&one,sizeof(one)) == -1) {
                DEBUG(DEBUG_WARNING, ("Failed to set TCP_NODELAY on fd - %s\n",
                                      strerror(errno)));
        }
        if (setsockopt(tnode->fd,SOL_SOCKET,SO_KEEPALIVE,(char *)&one,sizeof(one)) == -1) {
                DEBUG(DEBUG_WARNING, ("Failed to set KEEPALIVE on fd - %s\n",
                                      strerror(errno)));
        }

        ctdb_queue_set_fd(tnode->out_queue, tnode->fd);

        /* the queue subsystem now owns this fd */
        tnode->fd = -1;
}


/*
  called when we should try and establish a tcp connection to a node
*/
void ctdb_tcp_node_connect(struct tevent_context *ev, struct tevent_timer *te,
                           struct timeval t, void *private_data)
{
        struct ctdb_node *node = talloc_get_type(private_data,
                                                 struct ctdb_node);
        struct ctdb_tcp_node *tnode = talloc_get_type(node->private_data, 
                                                      struct ctdb_tcp_node);
        struct ctdb_context *ctdb = node->ctdb;
        ctdb_sock_addr sock_in;
        int sockin_size;
        int sockout_size;
        ctdb_sock_addr sock_out;

        ctdb_tcp_stop_connection(node);

        sock_out = node->address;

        tnode->fd = socket(sock_out.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
        if (tnode->fd == -1) {
                DEBUG(DEBUG_ERR, (__location__ "Failed to create socket\n"));
                return;
        }
        set_nonblocking(tnode->fd);
        set_close_on_exec(tnode->fd);

        DEBUG(DEBUG_DEBUG, (__location__ " Created TCP SOCKET FD:%d\n", tnode->fd));

        /* Bind our side of the socketpair to the same address we use to listen
         * on incoming CTDB traffic.
         * We must specify this address to make sure that the address we expose to
         * the remote side is actually routable in case CTDB traffic will run on
         * a dedicated non-routeable network.
         */
        sock_in = *ctdb->address;

        /* AIX libs check to see if the socket address and length
           arguments are consistent with each other on calls like
           connect().   Can not get by with just sizeof(sock_in),
           need sizeof(sock_in.ip).
        */
        switch (sock_in.sa.sa_family) {
        case AF_INET:
                sock_in.ip.sin_port = 0 /* Any port */;
                sockin_size = sizeof(sock_in.ip);
                sockout_size = sizeof(sock_out.ip);
                break;
        case AF_INET6:
                sock_in.ip6.sin6_port = 0 /* Any port */;
                sockin_size = sizeof(sock_in.ip6);
                sockout_size = sizeof(sock_out.ip6);
                break;
        default:
                DEBUG(DEBUG_ERR, (__location__ " unknown family %u\n",
                        sock_in.sa.sa_family));
                close(tnode->fd);
                return;
        }

        if (bind(tnode->fd, (struct sockaddr *)&sock_in, sockin_size) == -1) {
                DEBUG(DEBUG_ERR, (__location__ "Failed to bind socket %s(%d)\n",
                                  strerror(errno), errno));
                close(tnode->fd);
                return;
        }

        if (connect(tnode->fd, (struct sockaddr *)&sock_out, sockout_size) != 0 &&
            errno != EINPROGRESS) {
                ctdb_tcp_stop_connection(node);
                tnode->connect_te = tevent_add_timer(ctdb->ev, tnode,
                                                     timeval_current_ofs(1, 0),
                                                     ctdb_tcp_node_connect, node);
                return;
        }

        /* non-blocking connect - wait for write event */
        tnode->connect_fde = tevent_add_fd(node->ctdb->ev, tnode, tnode->fd,
                                           TEVENT_FD_WRITE|TEVENT_FD_READ,
                                           ctdb_node_connect_write, node);

        /* don't give it long to connect - retry in one second. This ensures
           that we find a node is up quickly (tcp normally backs off a syn reply
           delay by quite a lot) */
        tnode->connect_te = tevent_add_timer(ctdb->ev, tnode,
                                             timeval_current_ofs(1, 0),
                                             ctdb_tcp_node_connect, node);
}

/*
  called when we get contacted by another node
  currently makes no attempt to check if the connection is really from a ctdb
  node in our cluster
*/
static void ctdb_listen_event(struct tevent_context *ev, struct tevent_fd *fde,
                              uint16_t flags, void *private_data)
{
        struct ctdb_context *ctdb = talloc_get_type(private_data, struct ctdb_context);
        struct ctdb_tcp *ctcp = talloc_get_type(ctdb->private_data, struct ctdb_tcp);
        ctdb_sock_addr addr;
        socklen_t len;
        int fd, nodeid;
        struct ctdb_incoming *in;
        int one = 1;

        memset(&addr, 0, sizeof(addr));
        len = sizeof(addr);
        fd = accept(ctcp->listen_fd, (struct sockaddr *)&addr, &len);
        if (fd == -1) return;

        nodeid = ctdb_ip_to_nodeid(ctdb, &addr);

        if (nodeid == -1) {
                DEBUG(DEBUG_ERR, ("Refused connection from unknown node %s\n", ctdb_addr_to_str(&addr)));
                close(fd);
                return;
        }

        in = talloc_zero(ctcp, struct ctdb_incoming);
        in->fd = fd;
        in->ctdb = ctdb;

        set_nonblocking(in->fd);
        set_close_on_exec(in->fd);

        DEBUG(DEBUG_DEBUG, (__location__ " Created SOCKET FD:%d to incoming ctdb connection\n", fd));

        if (setsockopt(in->fd,SOL_SOCKET,SO_KEEPALIVE,(char *)&one,sizeof(one)) == -1) {
                DEBUG(DEBUG_WARNING, ("Failed to set KEEPALIVE on fd - %s\n",
                                      strerror(errno)));
        }

        in->queue = ctdb_queue_setup(ctdb, in, in->fd, CTDB_TCP_ALIGNMENT,
                                     ctdb_tcp_read_cb, in, "ctdbd-%s", ctdb_addr_to_str(&addr));
}


/*
  automatically find which address to listen on
*/
static int ctdb_tcp_listen_automatic(struct ctdb_context *ctdb)
{
        struct ctdb_tcp *ctcp = talloc_get_type(ctdb->private_data,
                                                struct ctdb_tcp);
        ctdb_sock_addr sock;
        int lock_fd, i;
        const char *lock_path = CTDB_RUNDIR "/.socket_lock";
        struct flock lock;
        int one = 1;
        int sock_size;
        struct tevent_fd *fde;

        /* If there are no nodes, then it won't be possible to find
         * the first one.  Log a failure and short circuit the whole
         * process.
         */
        if (ctdb->num_nodes == 0) {
                DEBUG(DEBUG_CRIT,("No nodes available to attempt bind to - is the nodes file empty?\n"));
                return -1;
        }

        /* in order to ensure that we don't get two nodes with the
           same adddress, we must make the bind() and listen() calls
           atomic. The SO_REUSEADDR setsockopt only prevents double
           binds if the first socket is in LISTEN state  */
        lock_fd = open(lock_path, O_RDWR|O_CREAT, 0666);
        if (lock_fd == -1) {
                DEBUG(DEBUG_CRIT,("Unable to open %s\n", lock_path));
                return -1;
        }

        lock.l_type = F_WRLCK;
        lock.l_whence = SEEK_SET;
        lock.l_start = 0;
        lock.l_len = 1;
        lock.l_pid = 0;

        if (fcntl(lock_fd, F_SETLKW, &lock) != 0) {
                DEBUG(DEBUG_CRIT,("Unable to lock %s\n", lock_path));
                close(lock_fd);
                return -1;
        }

        for (i=0; i < ctdb->num_nodes; i++) {
                if (ctdb->nodes[i]->flags & NODE_FLAGS_DELETED) {
                        continue;
                }
                sock = ctdb->nodes[i]->address;

                switch (sock.sa.sa_family) {
                case AF_INET:
                        sock_size = sizeof(sock.ip);
                        break;
                case AF_INET6:
                        sock_size = sizeof(sock.ip6);
                        break;
                default:
                        DEBUG(DEBUG_ERR, (__location__ " unknown family %u\n",
                                sock.sa.sa_family));
                        continue;
                }

                ctcp->listen_fd = socket(sock.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
                if (ctcp->listen_fd == -1) {
                        ctdb_set_error(ctdb, "socket failed\n");
                        continue;
                }

                set_close_on_exec(ctcp->listen_fd);

                if (setsockopt(ctcp->listen_fd,SOL_SOCKET,SO_REUSEADDR,
                               (char *)&one,sizeof(one)) == -1) {
                        DEBUG(DEBUG_WARNING, ("Failed to set REUSEADDR on fd - %s\n",
                                              strerror(errno)));
                }

                if (bind(ctcp->listen_fd, (struct sockaddr * )&sock, sock_size) == 0) {
                        break;
                }

                if (errno == EADDRNOTAVAIL) {
                        DEBUG(DEBUG_DEBUG,(__location__ " Failed to bind() to socket. %s(%d)\n",
                                        strerror(errno), errno));
                } else {
                        DEBUG(DEBUG_ERR,(__location__ " Failed to bind() to socket. %s(%d)\n",
                                        strerror(errno), errno));
                }

                close(ctcp->listen_fd);
                ctcp->listen_fd = -1;
        }

        if (i == ctdb->num_nodes) {
                DEBUG(DEBUG_CRIT,("Unable to bind to any of the node addresses - giving up\n"));
                goto failed;
        }
        ctdb->address = talloc_memdup(ctdb,
                                      &ctdb->nodes[i]->address,
                                      sizeof(ctdb_sock_addr));
        if (ctdb->address == NULL) {
                ctdb_set_error(ctdb, "Out of memory at %s:%d",
                               __FILE__, __LINE__);
                goto failed;
        }

        ctdb->name = talloc_asprintf(ctdb, "%s:%u",
                                     ctdb_addr_to_str(ctdb->address),
                                     ctdb_addr_to_port(ctdb->address));
        if (ctdb->name == NULL) {
                ctdb_set_error(ctdb, "Out of memory at %s:%d",
                               __FILE__, __LINE__);
                goto failed;
        }
        DEBUG(DEBUG_INFO,("ctdb chose network address %s\n", ctdb->name));

        if (listen(ctcp->listen_fd, 10) == -1) {
                goto failed;
        }

        fde = tevent_add_fd(ctdb->ev, ctcp, ctcp->listen_fd, TEVENT_FD_READ,
                            ctdb_listen_event, ctdb);
        tevent_fd_set_auto_close(fde);

        close(lock_fd);

        return 0;

failed:
        close(lock_fd);
        if (ctcp->listen_fd != -1) {
                close(ctcp->listen_fd);
                ctcp->listen_fd = -1;
        }
        return -1;
}


/*
  listen on our own address
*/
int ctdb_tcp_listen(struct ctdb_context *ctdb)
{
        struct ctdb_tcp *ctcp = talloc_get_type(ctdb->private_data,
                                                struct ctdb_tcp);
        ctdb_sock_addr sock;
        int sock_size;
        int one = 1;
        struct tevent_fd *fde;

        /* we can either auto-bind to the first available address, or we can
           use a specified address */
        if (!ctdb->address) {
                return ctdb_tcp_listen_automatic(ctdb);
        }

        sock = *ctdb->address;

        switch (sock.sa.sa_family) {
        case AF_INET:
                sock_size = sizeof(sock.ip);
                break;
        case AF_INET6:
                sock_size = sizeof(sock.ip6);
                break;
        default:
                DEBUG(DEBUG_ERR, (__location__ " unknown family %u\n",
                        sock.sa.sa_family));
                goto failed;
        }

        ctcp->listen_fd = socket(sock.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
        if (ctcp->listen_fd == -1) {
                ctdb_set_error(ctdb, "socket failed\n");
                return -1;
        }

        set_close_on_exec(ctcp->listen_fd);

        if (setsockopt(ctcp->listen_fd,SOL_SOCKET,SO_REUSEADDR,(char *)&one,sizeof(one)) == -1) {
                DEBUG(DEBUG_WARNING, ("Failed to set REUSEADDR on fd - %s\n",
                                      strerror(errno)));
        }

        if (bind(ctcp->listen_fd, (struct sockaddr * )&sock, sock_size) != 0) {
                DEBUG(DEBUG_ERR,(__location__ " Failed to bind() to socket. %s(%d)\n", strerror(errno), errno));
                goto failed;
        }

        if (listen(ctcp->listen_fd, 10) == -1) {
                goto failed;
        }

        fde = tevent_add_fd(ctdb->ev, ctcp, ctcp->listen_fd, TEVENT_FD_READ,
                            ctdb_listen_event, ctdb);
        tevent_fd_set_auto_close(fde);

        return 0;

failed:
        if (ctcp->listen_fd != -1) {
                close(ctcp->listen_fd);
        }
        ctcp->listen_fd = -1;
        return -1;
}