#include <TunOutDevice.h>
Inheritance diagram for TunOutDevice:
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 << "Can't parse non-UDP packets (e.g. ICMP) (yet)...\n"; 00065 goto parse_error; 00066 } 00067 payloadMsg = UDP->decapsulate(); 00068 00069 // parse payload 00070 payload = parser->encapsulatePayload(payloadMsg, &payloadlen); 00071 if (!payload ) { 00072 EV << "Can't parse packet payload, dropping packet\n"; 00073 goto parse_error; 00074 } 00075 00076 *length = payloadlen + iplen + udplen; 00077 if( *length > mtu ) { 00078 EV << "TunOutDevice::encapsulate: Error: Packet too big! Size = " << *length << " MTU = " << mtu << "\n"; 00079 goto parse_error; 00080 } 00081 00082 buf = new char[*length]; 00083 00084 // We use the buffer to build an ip packet. 00085 // To minimise unnecessary copying, we start with the payload 00086 // and write it to the end of the buffer 00087 memcpy( (buf + iplen + udplen), payload, payloadlen); 00088 00089 // write udp header in front of the payload 00090 udp_buf = (udphdr*) (buf + iplen); 00091 udp_buf->source = htons(UDP->sourcePort()); 00092 udp_buf->dest = htons(UDP->destinationPort()); 00093 udp_buf->len = htons(udplen + payloadlen); 00094 udp_buf->check = 0; 00095 00096 // Write udp pseudoheader in from of udp header 00097 // this will be overwritten by ip header 00098 pseudohdr = (udppseudohdr*) (buf + iplen - sizeof(struct udppseudohdr)); 00099 saddr = htonl(IP->srcAddress().getInt()); 00100 daddr = htonl(IP->destAddress().getInt()); 00101 pseudohdr->saddr = saddr; 00102 pseudohdr->daddr = daddr; 00103 pseudohdr->zero = 0; 00104 pseudohdr->protocol = IPPROTO_UDP; 00105 pseudohdr->lenght = udp_buf->len; 00106 00107 // compute UDP checksum 00108 udp_buf->check = cksum((uint16_t*) pseudohdr, sizeof(struct udppseudohdr) + udplen + payloadlen); 00109 00110 // write ip header to begin of buffer 00111 ip_buf = (iphdr*) buf; 00112 ip_buf->version = 4; // IPv4 00113 ip_buf->ihl = iplen / 4; 00114 ip_buf->tos = IP->diffServCodePoint(); 00115 ip_buf->tot_len = htons(*length); 00116 ip_buf->id = htons(IP->identification()); 00117 ip_buf->frag_off = htons(IP_DF); // DF, no fragments 00118 ip_buf->ttl = IP->timeToLive(); 00119 ip_buf->protocol = IPPROTO_UDP; 00120 ip_buf->saddr = saddr; 00121 ip_buf->daddr = daddr; 00122 ip_buf->check = 0; 00123 ip_buf->check = cksum((uint16_t*) ip_buf, iplen); 00124 00125 delete IP; 00126 delete UDP; 00127 delete payloadMsg; 00128 delete payload; 00129 00130 return buf; 00131 00132 parse_error: 00133 delete IP; 00134 delete UDP; 00135 delete payloadMsg; 00136 delete payload; 00137 return NULL; 00138 00139 }
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.
00145 { 00146 // Message starts with IP header 00147 iphdr* ip_buf = (iphdr*) buf; 00148 udphdr* udp_buf; 00149 IPDatagram* IP = new IPDatagram; 00150 UDPPacket* UDP = new UDPPacket; 00151 cMessage* payload = 0; 00152 unsigned int payloadLen, datagramlen; 00153 unsigned int packetlen = ntohs(ip_buf->tot_len); 00154 00155 // Parsing of IP header, sanity checks 00156 if ( packetlen != length ) { 00157 ev << "TunOutDevice: Dropping bogus packet, header says: length = " << packetlen << " but actual length = " << length <<".\n"; 00158 goto parse_error; 00159 } 00160 if ( packetlen > mtu ) { 00161 ev << "TunOutDevice: Dropping bogus packet, length = " << packetlen << " but mtu = " << mtu <<".\n"; 00162 goto parse_error; 00163 } 00164 if ( ip_buf->version != 4 ) { 00165 ev << "TunOutDevice: Dropping Packet: Packet is not IPv4.\n"; 00166 goto parse_error; 00167 } 00168 if ( ntohs(ip_buf->frag_off) & 0xBFFF ) { // mask DF bit 00169 ev << "TunOutDevice: Dropping Packet: Can't handle fragmented packets.\n"; 00170 goto parse_error; 00171 } 00172 if ( ip_buf->protocol != IPPROTO_UDP ) { // FIXME: allow ICMP packets 00173 ev << "TunOutDevice: Dropping Packet: Packet is not UDP.\n"; 00174 goto parse_error; 00175 } 00176 IP->setSrcAddress( IPAddress( ntohl(ip_buf->saddr) )); 00177 IP->setDestAddress( IPAddress( ntohl(ip_buf->daddr) )); 00178 IP->setTransportProtocol( ip_buf->protocol ); 00179 IP->setTimeToLive( ip_buf->ttl ); 00180 IP->setIdentification( ntohs(ip_buf->id) ); 00181 IP->setMoreFragments( false ); 00182 IP->setDontFragment( true ); 00183 IP->setFragmentOffset( 0 ); 00184 IP->setDiffServCodePoint( ip_buf->tos ); 00185 IP->setLength( ip_buf->ihl*32 ); 00186 // FIXME: check IP and UDP checksum... 00187 00188 // Parse UDP header, sanity checks 00189 udp_buf = (udphdr*)( ((uint32_t *)ip_buf) + ip_buf->ihl ); 00190 datagramlen = ntohs(udp_buf->len); 00191 if ( (datagramlen != packetlen - ip_buf->ihl*4) ) { 00192 ev << "TunOutDevice: Dropping Packet: Bogus UDP datagram length: len = " << datagramlen << " packetlen = " << packetlen << " ihl*4 " << ip_buf->ihl*4 << ".\n"; 00193 goto parse_error; 00194 } 00195 UDP->setSourcePort( ntohs( udp_buf->source )); 00196 UDP->setDestinationPort( ntohs( udp_buf->dest )); 00197 UDP->setByteLength( sizeof( struct udphdr ) ); 00198 00199 // parse payload 00200 payloadLen = datagramlen - sizeof( struct udphdr ); 00201 payload = parser->decapsulatePayload( ((char*) udp_buf) + sizeof( struct udphdr ), payloadLen ); 00202 if (!payload) { 00203 ev << "TunOutDevice: Parsing of Payload failed, dropping packet.\n"; 00204 goto parse_error; 00205 } 00206 // encapsulate messages 00207 UDP->encapsulate( payload ); 00208 IP->encapsulate( UDP ); 00209 00210 delete buf; 00211 delete addr; 00212 return IP; 00213 00214 // In case the parsing of the packet failed, free allocated memory 00215 parse_error: 00216 delete buf; 00217 delete addr; 00218 delete IP; 00219 delete UDP; 00220 return NULL; 00221 }
TunOutDevice::Module_Class_Members | ( | TunOutDevice | , | |
RealworldDevice | , | |||
0 | ||||
) |