mirror of
https://github.com/minexew/Shrine.git
synced 2026-05-26 16:36:09 +00:00
minexew
53 lines
1.4 KiB
HolyC
53 lines
1.4 KiB
HolyC
// vim: set ft=c:
|
|
|
|
#define ICMP_TYPE_ECHO_REPLY 0
|
|
#define ICMP_TYPE_ECHO_REQUEST 8
|
|
|
|
class CIcmpHeader {
|
|
U8 type;
|
|
U8 code;
|
|
U16 checksum;
|
|
U16 identifier;
|
|
U16 seq_number;
|
|
};
|
|
|
|
I64 IcmpSendReply(U32 dest_ip, U16 identifier, U16 seq_number, U16 request_checksum, U8* payload, I64 length) {
|
|
U8* frame;
|
|
I64 index = IPv4PacketAlloc(&frame, IP_PROTO_ICMP, IPv4GetAddress(), dest_ip, sizeof(CIcmpHeader) + length);
|
|
|
|
if (index < 0)
|
|
return index;
|
|
|
|
CIcmpHeader* hdr = frame;
|
|
hdr->type = ICMP_TYPE_ECHO_REPLY;
|
|
hdr->code = 0;
|
|
hdr->checksum = htons(ntohs(request_checksum) + 0x0800); // hack alert!
|
|
hdr->identifier = identifier;
|
|
hdr->seq_number = seq_number;
|
|
|
|
MemCpy(frame + sizeof(CIcmpHeader), payload, length);
|
|
return IPv4PacketFinish(index);
|
|
}
|
|
|
|
I64 IcmpHandler(CIPv4Packet* packet) {
|
|
if (packet->proto != IP_PROTO_ICMP)
|
|
return -1;
|
|
|
|
if (packet->length < sizeof(CIcmpHeader))
|
|
return -1;
|
|
|
|
CIcmpHeader* hdr = packet->data;
|
|
|
|
if (hdr->type == ICMP_TYPE_ECHO_REQUEST && hdr->code == 0) {
|
|
// This also makes sure that we don't stall NetHandlerTask
|
|
ArpCachePut(packet->source_ip, packet->l2_frame->source_addr);
|
|
|
|
IcmpSendReply(packet->source_ip, hdr->identifier, hdr->seq_number, hdr->checksum,
|
|
packet->data + sizeof(CIcmpHeader), packet->length - sizeof(CIcmpHeader));
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
RegisterL4Protocol(IP_PROTO_ICMP, &IcmpHandler);
|