68 lines
1.8 KiB
C++
68 lines
1.8 KiB
C++
#include "udp.h"
|
|
|
|
namespace udp {
|
|
|
|
UDPPacket::UDPPacket() {
|
|
memset(packet, 0, LEN);
|
|
}
|
|
|
|
UDPPacket::UDPPacket(const char* buffer, int len) {
|
|
memcpy(packet, buffer, len);
|
|
}
|
|
|
|
void UDPPacket::setSrcPort(uint16_t port) {
|
|
*(packet + 0) = port >> 8;
|
|
*(packet + 1) = port & 0xff;
|
|
}
|
|
|
|
void UDPPacket::setDstPort(uint16_t port) {
|
|
*(packet + 2) = port >> 8;
|
|
*(packet + 3) = port & 0xff;
|
|
}
|
|
|
|
uint16_t UDPPacket::getSrcPort() {
|
|
return (*(packet + 0) << 8) + (uint8_t)*(packet + 1);
|
|
}
|
|
uint16_t UDPPacket::getDstPort() {
|
|
return (*(packet + 2) << 8) + (uint8_t)*(packet + 3);
|
|
}
|
|
|
|
void UDPPacket::setPayload(const char* payload, int len) {
|
|
memcpy(packet + 8, payload, len);
|
|
*(packet + 4) = (len + 8) >> 8;
|
|
*(packet + 5) = (len + 8) & 0xff;
|
|
}
|
|
|
|
void UDPPacket::computeChecksum(const ipv6::IPv6Addr* src_addr, const ipv6::IPv6Addr* dst_addr, int len) {
|
|
memset(packet + 6, 0, 2);
|
|
uint16_t checksum = ipv6::compute_checksum(src_addr, dst_addr, ipv6::NH_UDP, len, packet, len);
|
|
memcpy(packet + 6, &checksum, 2);
|
|
}
|
|
|
|
void handleUDP(const ipv6::IPv6Addr* src_addr, const ipv6::IPv6Addr* dst_addr, const char* flow, char* packet, int len) {
|
|
UDPPacket udp_packet(packet, len);
|
|
|
|
/* swap ports */
|
|
uint16_t tmp;
|
|
tmp = udp_packet.getSrcPort();
|
|
udp_packet.setSrcPort(udp_packet.getDstPort());
|
|
udp_packet.setDstPort(tmp);
|
|
|
|
udp_packet.computeChecksum(src_addr, dst_addr, len);
|
|
|
|
/* prepare IPv6 packet */
|
|
ipv6::IPv6Packet reply_packet;
|
|
reply_packet.setPayload((char*)&udp_packet, len);
|
|
reply_packet.setFlow(flow);
|
|
|
|
//ipv6::IPv6Addr tmp_addr;
|
|
//memcpy(&tmp_addr, dst_addr, 16);
|
|
reply_packet.setSrcAddress(dst_addr);
|
|
//memcpy(&tmp_addr, src_addr, 16);
|
|
reply_packet.setDstAddress(src_addr);
|
|
reply_packet.setNextHeader(ipv6::NH_UDP);
|
|
slip::send((void*)&reply_packet, 40 + len);
|
|
}
|
|
|
|
}
|