mirror of https://github.com/oxen-io/lokinet
You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
84 lines
2.1 KiB
C++
84 lines
2.1 KiB
C++
#include <llarp/endian.h>
|
|
#include <algorithm>
|
|
#include <llarp/ip.hpp>
|
|
#include "llarp/buffer.hpp"
|
|
#include "mem.hpp"
|
|
#include <netinet/in.h>
|
|
#include <llarp/endian.h>
|
|
#include <map>
|
|
|
|
namespace llarp
|
|
{
|
|
namespace net
|
|
{
|
|
bool
|
|
IPv4Packet::Load(llarp_buffer_t pkt)
|
|
{
|
|
#ifndef MIN
|
|
#define MIN(a, b) (a < b ? a : b)
|
|
sz = MIN(pkt.sz, sizeof(buf));
|
|
#undef MIN
|
|
#endif
|
|
memcpy(buf, pkt.base, sz);
|
|
return true;
|
|
}
|
|
|
|
llarp_buffer_t
|
|
IPv4Packet::Buffer()
|
|
{
|
|
return llarp::InitBuffer(buf, sz);
|
|
}
|
|
|
|
static uint16_t
|
|
ipchksum(const byte_t *buf, size_t sz, uint32_t sum = 0)
|
|
{
|
|
while(sz > 1)
|
|
{
|
|
sum += *(const uint16_t *)buf;
|
|
sz -= sizeof(uint16_t);
|
|
buf += sizeof(uint16_t);
|
|
}
|
|
if(sz > 0)
|
|
sum += *(const byte_t *)buf;
|
|
|
|
while(sum >> 16)
|
|
sum = (sum & 0xffff) + (sum >> 16);
|
|
|
|
return ~sum;
|
|
}
|
|
|
|
static std::map<
|
|
byte_t, std::function< void(const ip_header *, byte_t *, size_t) > >
|
|
protoCheckSummer = {
|
|
{IPPROTO_ICMP,
|
|
[](const ip_header *hdr, byte_t *buf, size_t sz) {
|
|
auto len = hdr->ihl * 4;
|
|
uint16_t *check = (uint16_t *)buf + len + 2;
|
|
*check = 0;
|
|
*check = ipchksum(buf, sz);
|
|
}},
|
|
{IPPROTO_TCP, [](const ip_header *hdr, byte_t *pkt, size_t sz) {
|
|
auto len = hdr->ihl * 4;
|
|
uint16_t *check = (uint16_t *)pkt + 28 + len;
|
|
*check = 0;
|
|
*check =
|
|
ipchksum(pkt, sz - len,
|
|
hdr->saddr + hdr->daddr + IPPROTO_TCP + (sz - len));
|
|
}}};
|
|
void
|
|
IPv4Packet::UpdateChecksum()
|
|
{
|
|
auto hdr = Header();
|
|
hdr->check = 0;
|
|
auto len = hdr->ihl * 4;
|
|
hdr->check = ipchksum(buf, len);
|
|
auto proto = hdr->protocol;
|
|
auto itr = protoCheckSummer.find(proto);
|
|
if(itr != protoCheckSummer.end())
|
|
{
|
|
itr->second(hdr, buf, sz);
|
|
}
|
|
}
|
|
} // namespace net
|
|
} // namespace llarp
|