bfdbb8f260
This commit updates all authorship and copyright information to include a standard header that references the AUTHORS and CREDITS file. This standard header was written by the Debian legal team at the request of Franck Joncourt.
229 lines
7.0 KiB
C
229 lines
7.0 KiB
C
/*
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*****************************************************************************
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*
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* File: tcp_server.c
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*
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* Purpose: Spawns off a dummy tcp server for fwknopd. Its purpose is
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* to accept a tcp connection, then drop it after the first packet.
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*
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* Fwknop is developed primarily by the people listed in the file 'AUTHORS'.
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* Copyright (C) 2009–2014 fwknop developers and contributors. For a full
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* list of contributors, see the file 'CREDITS'.
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*
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* License (GNU General Public License):
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
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* USA
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*
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*****************************************************************************
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*/
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#include "fwknopd_common.h"
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#include "tcp_server.h"
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#include "log_msg.h"
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#include "utils.h"
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#include <errno.h>
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#if HAVE_SYS_SOCKET_H
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#include <sys/socket.h>
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#endif
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#if HAVE_ARPA_INET_H
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#include <arpa/inet.h>
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#endif
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#if HAVE_NETDB
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#include <netdb.h>
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#endif
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#include <fcntl.h>
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#include <sys/select.h>
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/* Fork off and run a "dummy" TCP server. The return value is the PID of
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* the child process or -1 if there is a fork error.
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*/
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int
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run_tcp_server(fko_srv_options_t *opts)
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{
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pid_t pid, ppid;
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int s_sock, c_sock, sfd_flags, clen, selval;
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int reuse_addr = 1, is_err;
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fd_set sfd_set;
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struct sockaddr_in saddr, caddr;
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struct timeval tv;
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char sipbuf[MAX_IPV4_STR_LEN] = {0};
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unsigned short port;
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port = strtol_wrapper(opts->config[CONF_TCPSERV_PORT],
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0, MAX_PORT, NO_EXIT_UPON_ERR, &is_err);
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if(is_err != FKO_SUCCESS)
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{
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log_msg(LOG_ERR, "[*] Invalid max TCPSERV_PORT value.");
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exit(EXIT_FAILURE);
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}
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log_msg(LOG_INFO, "Kicking off TCP server to listen on port %i.", port);
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/* Fork off a child process to run the command and provide its outputs.
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*/
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pid = fork();
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/* Non-zero pid means we are the parent or there was a fork error.
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* in either case we simply return that value to the caller.
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*/
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if (pid != 0)
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{
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opts->tcp_server_pid = pid;
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return(pid);
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}
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/* Get our parent PID so we can periodically check for it. We want to
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* know when it goes away so we can to.
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*/
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ppid = getppid();
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/* We are the child. The first thing to do is close our copy of the
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* parent PID file so we don't end up holding the lock if the parent
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* suffers a sudden death that doesn't take us out too.
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*/
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close(opts->lock_fd);
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/* Now, let's make a TCP server
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*/
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if ((s_sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0)
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{
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log_msg(LOG_ERR, "run_tcp_server: socket() failed: %s",
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strerror(errno));
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exit(EXIT_FAILURE);
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}
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/* So that we can re-bind to it without TIME_WAIT problems
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*/
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if(setsockopt(s_sock, SOL_SOCKET, SO_REUSEADDR, &reuse_addr, sizeof(reuse_addr)) == -1)
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{
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log_msg(LOG_ERR, "run_tcp_server: setsockopt error: %s",
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strerror(errno));
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exit(EXIT_FAILURE);
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}
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/* Make our main socket non-blocking so we don't have to be stuck on
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* listening for incoming connections.
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*/
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if((sfd_flags = fcntl(s_sock, F_GETFL, 0)) < 0)
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{
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log_msg(LOG_ERR, "run_tcp_server: fcntl F_GETFL error: %s",
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strerror(errno));
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exit(EXIT_FAILURE);
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}
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sfd_flags |= O_NONBLOCK;
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if(fcntl(s_sock, F_SETFL, sfd_flags) < 0)
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{
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log_msg(LOG_ERR, "run_tcp_server: fcntl F_SETFL error setting O_NONBLOCK: %s",
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strerror(errno));
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exit(EXIT_FAILURE);
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}
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/* Construct local address structure */
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memset(&saddr, 0, sizeof(saddr));
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saddr.sin_family = AF_INET; /* Internet address family */
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saddr.sin_addr.s_addr = htonl(INADDR_ANY); /* Any incoming interface */
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saddr.sin_port = htons(port); /* Local port */
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/* Bind to the local address */
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if (bind(s_sock, (struct sockaddr *) &saddr, sizeof(saddr)) < 0)
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{
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log_msg(LOG_ERR, "run_tcp_server: bind() failed: %s",
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strerror(errno));
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exit(EXIT_FAILURE);
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}
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/* Mark the socket so it will listen for incoming connections
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* (but only one at a time)
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*/
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if (listen(s_sock, 1) < 0)
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{
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log_msg(LOG_ERR, "run_tcp_server: listen() failed: %s",
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strerror(errno));
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exit(EXIT_FAILURE);
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}
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clen = sizeof(caddr);
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/* Now loop and accept and drop connections after the first packet or a
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* short timeout.
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*/
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while(1)
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{
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/* Initialize and setup the socket for select.
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*/
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FD_ZERO(&sfd_set);
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FD_SET(s_sock, &sfd_set);
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/* Set our select timeout to 200 ms.
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*/
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tv.tv_sec = 0;
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tv.tv_usec = 200000;
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selval = select(s_sock+1, &sfd_set, NULL, NULL, &tv);
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if(selval == -1)
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{
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/* Select error - so kill the child and bail.
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*/
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log_msg(LOG_ERR, "run_tcp_server: select error socket: %s",
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strerror(errno));
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exit(EXIT_FAILURE);
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}
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if(selval == 0)
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{
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/* Timeout - So we check to make sure our parent is still there by simply
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* using kill(ppid, 0) and checking the return value.
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*/
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if(kill(ppid, 0) != 0 && errno == ESRCH)
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exit(EXIT_FAILURE);
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continue;
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}
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/* Wait for a client to connect
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*/
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if((c_sock = accept(s_sock, (struct sockaddr *) &caddr, (socklen_t *)&clen)) < 0)
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{
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log_msg(LOG_ERR, "run_tcp_server: accept() failed: %s",
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strerror(errno));
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exit(EXIT_FAILURE); /* Should this be fatal? */
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}
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if(opts->verbose)
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{
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memset(sipbuf, 0x0, MAX_IPV4_STR_LEN);
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inet_ntop(AF_INET, &(caddr.sin_addr.s_addr), sipbuf, MAX_IPV4_STR_LEN);
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log_msg(LOG_INFO, "tcp_server: Got TCP connection from %s.", sipbuf);
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}
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/* Though hacky and clunky, we just sleep for a second then
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* close the socket. No need to read or write anything. This
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* just gives the client a sufficient window to send their
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* request on this socket. In any case the socket is closed
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* after that time.
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*/
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usleep(1000000);
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shutdown(c_sock, SHUT_RDWR);
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close(c_sock);
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}
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}
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/***EOF***/
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