#include <TunOutDevice.h>
WARNING: This does ONLY work with the combination IPv4|UDP|OverlayMessage
Public Member Functions | |
Module_Class_Members (TunOutDevice, RealworldDevice, 0) | |
Protected Member Functions | |
virtual char * | encapsulate (cMessage *msg, unsigned int *length, sockaddr **addr, socklen_t *addrlen) |
Converts an IP datagram to a data block for sending it to the (realworld) network. | |
virtual cMessage * | decapsulate (char *buf, uint32_t length, sockaddr *addr, socklen_t addrlen) |
Parses data received from the (realworld) network and converts it into a cMessage. |
char * TunOutDevice::encapsulate | ( | cMessage * | msg, | |
unsigned int * | length, | |||
sockaddr ** | addr, | |||
socklen_t * | addrlen | |||
) | [protected, virtual] |
Converts an IP datagram to a data block for sending it to the (realworld) network.
msg | A pointer to the message to be converted | |
length | A pointer to an int that will hold the length of the converted data | |
addr | Ignored (set to 0) | |
addrlen | Ignored (set to 0) |
Implements RealworldConnector.
00038 { 00039 *addr = 0; 00040 *addrlen = 0; 00041 00042 struct udppseudohdr { 00043 uint32_t saddr; 00044 uint32_t daddr; 00045 uint8_t zero; 00046 uint8_t protocol; 00047 uint16_t lenght; 00048 } 00049 * pseudohdr; 00050 00051 unsigned int payloadlen; 00052 static unsigned int iplen = 20; // we don't generate IP options 00053 static unsigned int udplen = 8; 00054 cMessage* payloadMsg = NULL; 00055 char* buf = NULL, *payload = NULL; 00056 uint32_t saddr, daddr; 00057 iphdr* ip_buf; 00058 udphdr* udp_buf; 00059 00060 IPDatagram* IP = check_and_cast<IPDatagram*>(msg); 00061 // FIXME: Cast ICMP-Messages 00062 UDPPacket* UDP = dynamic_cast<UDPPacket*>(IP->decapsulate()); 00063 if (!UDP) { 00064 EV << "[TunOutDevice::encapsulate()]\n" 00065 << " Can't parse non-UDP packets (e.g. ICMP) (yet)" 00066 << endl; 00067 goto parse_error; 00068 } 00069 payloadMsg = UDP->decapsulate(); 00070 00071 // parse payload 00072 payload = parser->encapsulatePayload(payloadMsg, &payloadlen); 00073 if (!payload ) { 00074 EV << "[TunOutDevice::encapsulate()]\n" 00075 << " Can't parse packet payload, dropping packet" 00076 << endl; 00077 goto parse_error; 00078 } 00079 00080 *length = payloadlen + iplen + udplen; 00081 if( *length > mtu ) { 00082 EV << "[TunOutDevice::encapsulate()]\n" 00083 << " Error: Packet too big! Size = " << *length << " MTU = " << mtu 00084 << endl; 00085 goto parse_error; 00086 } 00087 00088 buf = new char[*length]; 00089 00090 // We use the buffer to build an ip packet. 00091 // To minimise unnecessary copying, we start with the payload 00092 // and write it to the end of the buffer 00093 memcpy( (buf + iplen + udplen), payload, payloadlen); 00094 00095 // write udp header in front of the payload 00096 udp_buf = (udphdr*) (buf + iplen); 00097 udp_buf->source = htons(UDP->sourcePort()); 00098 udp_buf->dest = htons(UDP->destinationPort()); 00099 udp_buf->len = htons(udplen + payloadlen); 00100 udp_buf->check = 0; 00101 00102 // Write udp pseudoheader in from of udp header 00103 // this will be overwritten by ip header 00104 pseudohdr = (udppseudohdr*) (buf + iplen - sizeof(struct udppseudohdr)); 00105 saddr = htonl(IP->srcAddress().getInt()); 00106 daddr = htonl(IP->destAddress().getInt()); 00107 pseudohdr->saddr = saddr; 00108 pseudohdr->daddr = daddr; 00109 pseudohdr->zero = 0; 00110 pseudohdr->protocol = IPPROTO_UDP; 00111 pseudohdr->lenght = udp_buf->len; 00112 00113 // compute UDP checksum 00114 udp_buf->check = cksum((uint16_t*) pseudohdr, sizeof(struct udppseudohdr) + udplen + payloadlen); 00115 00116 // write ip header to begin of buffer 00117 ip_buf = (iphdr*) buf; 00118 ip_buf->version = 4; // IPv4 00119 ip_buf->ihl = iplen / 4; 00120 ip_buf->tos = IP->diffServCodePoint(); 00121 ip_buf->tot_len = htons(*length); 00122 ip_buf->id = htons(IP->identification()); 00123 ip_buf->frag_off = htons(IP_DF); // DF, no fragments 00124 ip_buf->ttl = IP->timeToLive(); 00125 ip_buf->protocol = IPPROTO_UDP; 00126 ip_buf->saddr = saddr; 00127 ip_buf->daddr = daddr; 00128 ip_buf->check = 0; 00129 ip_buf->check = cksum((uint16_t*) ip_buf, iplen); 00130 00131 delete IP; 00132 delete UDP; 00133 delete payloadMsg; 00134 delete payload; 00135 00136 return buf; 00137 00138 parse_error: 00139 delete IP; 00140 delete UDP; 00141 delete payloadMsg; 00142 delete payload; 00143 return NULL; 00144 00145 }
cMessage * TunOutDevice::decapsulate | ( | char * | buf, | |
uint32_t | length, | |||
sockaddr * | addr, | |||
socklen_t | addrlen | |||
) | [protected, virtual] |
Parses data received from the (realworld) network and converts it into a cMessage.
buf | A pointer to the data to be parsed | |
length | The lenght of the buffer in bytes | |
addr | Ignored (deleted) | |
addrlen | Ignored |
Implements RealworldConnector.
00151 { 00152 // Message starts with IP header 00153 iphdr* ip_buf = (iphdr*) buf; 00154 udphdr* udp_buf; 00155 IPDatagram* IP = new IPDatagram; 00156 UDPPacket* UDP = new UDPPacket; 00157 cMessage* payload = 0; 00158 unsigned int payloadLen, datagramlen; 00159 unsigned int packetlen = ntohs(ip_buf->tot_len); 00160 00161 // Parsing of IP header, sanity checks 00162 if ( packetlen != length ) { 00163 EV << "[TunOutDevice::decapsulate()]\n" 00164 << " Dropping bogus packet, header says: length = " << packetlen << "\n" 00165 << " but actual length = " << length 00166 << endl; 00167 goto parse_error; 00168 } 00169 if ( packetlen > mtu ) { 00170 EV << "[TunOutDevice::decapsulate()]\n" 00171 << " Dropping bogus packet, length = " << packetlen << "\n" 00172 << " but mtu = " << mtu 00173 << endl; 00174 goto parse_error; 00175 } 00176 if ( ip_buf->version != 4 ) { 00177 EV << "[TunOutDevice::decapsulate()]\n" 00178 << " Dropping Packet: Packet is not IPv4" 00179 << endl; 00180 goto parse_error; 00181 } 00182 if ( ntohs(ip_buf->frag_off) & 0xBFFF ) { // mask DF bit 00183 EV << "[TunOutDevice::decapsulate()]\n" 00184 << " Dropping Packet: Can't handle fragmented packets" 00185 << endl; 00186 goto parse_error; 00187 } 00188 if ( ip_buf->protocol != IPPROTO_UDP ) { // FIXME: allow ICMP packets 00189 EV << "[TunOutDevice::decapsulate()]\n" 00190 << " Dropping Packet: Packet is not UDP" 00191 << endl; 00192 goto parse_error; 00193 } 00194 IP->setSrcAddress( IPAddress( ntohl(ip_buf->saddr) )); 00195 IP->setDestAddress( IPAddress( ntohl(ip_buf->daddr) )); 00196 IP->setTransportProtocol( ip_buf->protocol ); 00197 IP->setTimeToLive( ip_buf->ttl ); 00198 IP->setIdentification( ntohs(ip_buf->id) ); 00199 IP->setMoreFragments( false ); 00200 IP->setDontFragment( true ); 00201 IP->setFragmentOffset( 0 ); 00202 IP->setDiffServCodePoint( ip_buf->tos ); 00203 IP->setLength( ip_buf->ihl*32 ); 00204 // FIXME: check IP and UDP checksum... 00205 00206 // Parse UDP header, sanity checks 00207 udp_buf = (udphdr*)( ((uint32_t *)ip_buf) + ip_buf->ihl ); 00208 datagramlen = ntohs(udp_buf->len); 00209 if ( (datagramlen != packetlen - ip_buf->ihl*4) ) { 00210 EV << "[TunOutDevice::decapsulate()]\n" 00211 << " Dropping Packet: Bogus UDP datagram length: len = " << datagramlen << "\n" 00212 << " packetlen = " << packetlen << " ihl*4 " << ip_buf->ihl*4 00213 << endl; 00214 goto parse_error; 00215 } 00216 UDP->setSourcePort( ntohs( udp_buf->source )); 00217 UDP->setDestinationPort( ntohs( udp_buf->dest )); 00218 UDP->setByteLength( sizeof( struct udphdr ) ); 00219 00220 // parse payload 00221 payloadLen = datagramlen - sizeof( struct udphdr ); 00222 payload = parser->decapsulatePayload( ((char*) udp_buf) + sizeof( struct udphdr ), payloadLen ); 00223 if (!payload) { 00224 EV << "[TunOutDevice::decapsulate()]\n" 00225 << " Parsing of Payload failed, dropping packet" 00226 << endl; 00227 goto parse_error; 00228 } 00229 // encapsulate messages 00230 UDP->encapsulate( payload ); 00231 IP->encapsulate( UDP ); 00232 00233 delete buf; 00234 delete addr; 00235 return IP; 00236 00237 // In case the parsing of the packet failed, free allocated memory 00238 parse_error: 00239 delete buf; 00240 delete addr; 00241 delete IP; 00242 delete UDP; 00243 return NULL; 00244 }
TunOutDevice::Module_Class_Members | ( | TunOutDevice | , | |
RealworldDevice | , | |||
0 | ||||
) |