447 lines
11 KiB
C
447 lines
11 KiB
C
/**
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* @file socket.c
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*
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* @brief Implementation of socket_t.
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*
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*/
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/*
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* Copyright (C) 2006 Tobias Brunner, Daniel Roethlisberger
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* Copyright (C) 2005 Jan Hutter, Martin Willi
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* Hochschule fuer Technik Rapperswil
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* Copyright (C) 1998-2002 D. Hugh Redelmeier.
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* Copyright (C) 1997 Angelos D. Keromytis.
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*
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* Some parts of interface lookup code from pluto.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*/
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#include <pthread.h>
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <string.h>
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#include <errno.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <fcntl.h>
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#include <sys/ioctl.h>
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#include <netinet/in.h>
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#include <netinet/ip.h>
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#include <netinet/udp.h>
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#include <linux/ipsec.h>
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#include <linux/filter.h>
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#include "socket.h"
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#include <daemon.h>
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#include <utils/logger_manager.h>
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/* constants for packet handling */
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#define IP_LEN sizeof(struct iphdr)
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#define UDP_LEN sizeof(struct udphdr)
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#define MARKER_LEN sizeof(u_int32_t)
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/* offsets for packet handling */
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#define IP 0
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#define UDP IP + IP_LEN
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#define IKE UDP + UDP_LEN
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/* from linux/in.h */
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#ifndef IP_IPSEC_POLICY
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#define IP_IPSEC_POLICY 16
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#endif /*IP_IPSEC_POLICY*/
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/* from linux/udp.h */
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#ifndef UDP_ENCAP
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#define UDP_ENCAP 100
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#endif /*UDP_ENCAP*/
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#ifndef UDP_ENCAP_ESPINUDP
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#define UDP_ENCAP_ESPINUDP 2
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#endif /*UDP_ENCAP_ESPINUDP*/
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typedef struct private_socket_t private_socket_t;
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/**
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* Private data of an socket_t object
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*/
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struct private_socket_t{
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/**
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* public functions
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*/
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socket_t public;
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/**
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* regular port
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*/
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int port;
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/**
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* port used for nat-t
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*/
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int natt_port;
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/**
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* raw socket (receiver)
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*/
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int raw_fd;
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/**
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* send socket on regular port
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*/
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int send_fd;
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/**
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* send socket on nat-t port
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*/
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int natt_fd;
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/**
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* logger for this socket
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*/
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logger_t *logger;
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/**
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* Setup a send socket
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*
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* @param this calling object
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* @param port the port
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* @param send_fd returns the file descriptor of this new socket
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*/
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status_t (*setup_send_socket) (private_socket_t *this, u_int16_t port, int *send_fd);
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/**
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* Initialize
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*
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* @param this calling object
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*/
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status_t (*initialize) (private_socket_t *this);
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};
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/**
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* implementation of socket_t.receive
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*/
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static status_t receiver(private_socket_t *this, packet_t **packet)
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{
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char buffer[MAX_PACKET];
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chunk_t data;
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packet_t *pkt;
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struct iphdr *ip;
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struct udphdr *udp;
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host_t *source, *dest;
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int bytes_read = 0;
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int data_offset, oldstate;
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this->logger->log(this->logger, CONTROL|LEVEL1, "receive from raw socket");
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/* allow cancellation while blocking on recv() */
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pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, &oldstate);
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bytes_read = recv(this->raw_fd, buffer, MAX_PACKET, 0);
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pthread_setcancelstate(oldstate, NULL);
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if (bytes_read < 0)
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{
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this->logger->log(this->logger, ERROR, "error reading from socket: %s", strerror(errno));
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return FAILED;
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}
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/* read source/dest from raw IP/UDP header */
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ip = (struct iphdr*) buffer;
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udp = (struct udphdr*) (buffer + IP_LEN);
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source = host_create_from_hdr(ip->saddr, udp->source);
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dest = host_create_from_hdr(ip->daddr, udp->dest);
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pkt = packet_create();
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pkt->set_source(pkt, source);
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pkt->set_destination(pkt, dest);
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this->logger->log(this->logger, CONTROL, "received packet: from %s:%d to %s:%d",
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source->get_address(source), source->get_port(source),
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dest->get_address(dest), dest->get_port(dest));
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data_offset = IP_LEN + UDP_LEN;
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/* remove non esp marker */
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if (dest->get_port(dest) == this->natt_port)
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{
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data_offset += MARKER_LEN;
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}
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/* fill in packet */
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data.len = bytes_read - data_offset;
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data.ptr = malloc(data.len);
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memcpy(data.ptr, buffer + data_offset, data.len);
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pkt->set_data(pkt, data);
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/* return packet */
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*packet = pkt;
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return SUCCESS;
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}
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/**
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* implementation of socket_t.send
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*/
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status_t sender(private_socket_t *this, packet_t *packet)
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{
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int sport, fd;
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ssize_t bytes_sent;
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chunk_t data, marked;
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host_t *src, *dst;
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src = packet->get_source(packet);
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dst = packet->get_destination(packet);
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data = packet->get_data(packet);
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this->logger->log(this->logger, CONTROL, "sending packet: from %s:%d to %s:%d",
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src->get_address(src), src->get_port(src),
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dst->get_address(dst), dst->get_port(dst));
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/* send data */
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sport = src->get_port(src);
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if (sport == this->port)
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{
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fd = this->send_fd;
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}
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else if (sport == this->natt_port)
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{
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fd = this->natt_fd;
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/* NAT keepalives without marker */
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if (data.len != 1 || data.ptr[0] != 0xFF)
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{
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/* add non esp marker to packet */
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if (data.len > MAX_PACKET - MARKER_LEN)
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{
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this->logger->log(this->logger, ERROR, "unable to send packet: it's too big");
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return FAILED;
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}
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marked = chunk_alloc(data.len + MARKER_LEN);
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memset(marked.ptr, 0, MARKER_LEN);
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memcpy(marked.ptr + MARKER_LEN, data.ptr, data.len);
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packet->set_data(packet, marked); /* let the packet do the clean up for us */
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data = marked;
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}
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}
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else
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{
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this->logger->log(this->logger, ERROR, "unable to locate a send socket for port: %d", sport);
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return FAILED;
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}
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bytes_sent = sendto(fd, data.ptr, data.len, 0,
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dst->get_sockaddr(dst), *(dst->get_sockaddr_len(dst)));
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if (bytes_sent != data.len)
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{
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this->logger->log(this->logger, ERROR, "error writing to socket: %s", strerror(errno));
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return FAILED;
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}
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return SUCCESS;
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}
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/**
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* setup a send socket on a specified port
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*/
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static status_t setup_send_socket(private_socket_t *this, u_int16_t port, int *send_fd) {
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int on = TRUE;
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struct sockaddr_in addr;
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int fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
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if (fd < 0)
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{
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this->logger->log(this->logger, ERROR, "could not open IPv4 send socket!");
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return FAILED;
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}
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if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (void*)&on, sizeof(on)) < 0)
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{
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this->logger->log(this->logger, ERROR, "unable to set SO_REUSEADDR on send socket!");
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close(fd);
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return FAILED;
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}
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struct sadb_x_policy policy;
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int level, opt;
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policy.sadb_x_policy_len = sizeof(policy) / sizeof(u_int64_t);
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policy.sadb_x_policy_exttype = SADB_X_EXT_POLICY;
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policy.sadb_x_policy_type = IPSEC_POLICY_BYPASS;
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policy.sadb_x_policy_dir = IPSEC_DIR_INBOUND;
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policy.sadb_x_policy_reserved = 0;
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policy.sadb_x_policy_id = 0;
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/* ipv6
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* level = IPPROTO_IPV6;
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* opt = IPV6_IPSEC_POLICY;
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*/
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level = IPPROTO_IP;
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opt = IP_IPSEC_POLICY;
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if (setsockopt(fd, level, opt, &policy, sizeof(policy)) < 0)
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{
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this->logger->log(this->logger, ERROR, "unable to set IPSEC_POLICY on send socket!");
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close(fd);
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return FAILED;
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}
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policy.sadb_x_policy_dir = IPSEC_DIR_OUTBOUND;
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if (setsockopt(fd, level, opt, &policy, sizeof(policy)) < 0)
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{
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this->logger->log(this->logger, ERROR, "unable to set IPSEC_POLICY on send socket!");
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close(fd);
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return FAILED;
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}
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/* bind the send socket */
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addr.sin_family = AF_INET;
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addr.sin_addr.s_addr = INADDR_ANY;
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addr.sin_port = htons(port);
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if (bind(fd, (struct sockaddr*)&addr, sizeof(addr)) < 0)
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{
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this->logger->log(this->logger, ERROR, "unable to bind send socket: %s!", strerror(errno));
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return FAILED;
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}
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*send_fd = fd;
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return SUCCESS;
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}
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/**
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* Initialize all sub sockets
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*/
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static status_t initialize(private_socket_t *this)
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{
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/* This filter code filters out all non-IKEv2 traffic on
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* a SOCK_RAW IP_PROTP_UDP socket. Handling of other
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* IKE versions is done in pluto.
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*/
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struct sock_filter ikev2_filter_code[] =
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{
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/* Protocol must be UDP */
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BPF_STMT(BPF_LD+BPF_B+BPF_ABS, IP + 9),
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BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, IPPROTO_UDP, 0, 15),
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/* Destination Port must be either port or natt_port */
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BPF_STMT(BPF_LD+BPF_H+BPF_ABS, UDP + 2),
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BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, this->port, 1, 0),
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BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, this->natt_port, 5, 12),
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/* port */
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/* IKE version must be 2.0 */
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BPF_STMT(BPF_LD+BPF_B+BPF_ABS, IKE + 17),
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BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, 0x20, 0, 10),
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/* packet length is length in IKEv2 header + ip header + udp header */
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BPF_STMT(BPF_LD+BPF_W+BPF_ABS, IKE + 24),
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BPF_STMT(BPF_ALU+BPF_ADD+BPF_K, IP_LEN + UDP_LEN),
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BPF_STMT(BPF_RET+BPF_A, 0),
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/* natt_port */
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/* nat-t: check for marker */
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BPF_STMT(BPF_LD+BPF_W+BPF_ABS, IKE),
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BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, 0, 0, 5),
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/* nat-t: IKE version must be 2.0 */
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BPF_STMT(BPF_LD+BPF_B+BPF_ABS, IKE + MARKER_LEN + 17),
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BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, 0x20, 0, 3),
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/* nat-t: packet length is length in IKEv2 header + ip header + udp header + non esp marker */
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BPF_STMT(BPF_LD+BPF_W+BPF_ABS, IKE + MARKER_LEN + 24),
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BPF_STMT(BPF_ALU+BPF_ADD+BPF_K, IP_LEN + UDP_LEN + MARKER_LEN),
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BPF_STMT(BPF_RET+BPF_A, 0),
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/* packet doesn't match, ignore */
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BPF_STMT(BPF_RET+BPF_K, 0),
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};
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/* Filter struct to use with setsockopt */
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struct sock_fprog ikev2_filter = {
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sizeof(ikev2_filter_code) / sizeof(struct sock_filter),
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ikev2_filter_code
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};
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/* set up raw socket */
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this->raw_fd = socket(PF_INET, SOCK_RAW, IPPROTO_UDP);
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if (this->raw_fd < 0)
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{
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this->logger->log(this->logger, ERROR, "unable to create raw socket!");
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return FAILED;
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}
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if (setsockopt(this->raw_fd, SOL_SOCKET, SO_ATTACH_FILTER, &ikev2_filter, sizeof(ikev2_filter)) < 0)
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{
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this->logger->log(this->logger, ERROR, "unable to attach IKEv2 filter to raw socket!");
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close(this->raw_fd);
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return FAILED;
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}
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/* setup the send sockets */
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if (this->setup_send_socket(this, this->port, &this->send_fd) != SUCCESS)
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{
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this->logger->log(this->logger, ERROR, "unable to setup send socket on port %d!", this->port);
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return FAILED;
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}
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if (this->setup_send_socket(this, this->natt_port, &this->natt_fd) != SUCCESS)
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{
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this->logger->log(this->logger, ERROR, "unable to setup send socket on port %d!", this->natt_port);
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return FAILED;
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}
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else
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{
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int type = UDP_ENCAP_ESPINUDP;
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if (setsockopt(this->natt_fd, SOL_UDP, UDP_ENCAP, &type, sizeof(type)) < 0)
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{
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this->logger->log(this->logger, ERROR,
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"unable to set UDP_ENCAP on natt send socket! NAT-T may fail! error: %s",
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strerror(errno));
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}
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}
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return SUCCESS;
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}
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/**
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* implementation of socket_t.destroy
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*/
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static void destroy(private_socket_t *this)
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{
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close(this->natt_fd);
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close(this->send_fd);
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close(this->raw_fd);
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free(this);
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}
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/*
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* See header for description
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*/
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socket_t *socket_create(u_int16_t port, u_int16_t natt_port)
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{
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private_socket_t *this = malloc_thing(private_socket_t);
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/* private functions */
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this->initialize = (status_t(*)(private_socket_t*))initialize;
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this->setup_send_socket = (status_t(*)(private_socket_t*,u_int16_t, int*))setup_send_socket;
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/* public functions */
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this->public.send = (status_t(*)(socket_t*, packet_t*))sender;
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this->public.receive = (status_t(*)(socket_t*, packet_t**))receiver;
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this->public.destroy = (void(*)(socket_t*)) destroy;
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this->logger = logger_manager->get_logger(logger_manager, SOCKET);
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this->port = port;
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this->natt_port = natt_port;
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if (this->initialize(this) != SUCCESS)
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{
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free(this);
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charon->kill(charon, "could not init socket!");
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}
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return (socket_t*)this;
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}
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