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.
446 lines
13 KiB
C++
446 lines
13 KiB
C++
#include <net/ip.hpp>
|
|
|
|
#include <util/buffer.hpp>
|
|
#include <util/endian.hpp>
|
|
#include <util/mem.hpp>
|
|
|
|
#ifndef _WIN32
|
|
#include <netinet/in.h>
|
|
#endif
|
|
|
|
#include <algorithm>
|
|
#include <map>
|
|
|
|
namespace llarp
|
|
{
|
|
namespace net
|
|
{
|
|
inline static uint32_t *
|
|
in6_uint32_ptr(in6_addr &addr)
|
|
{
|
|
return (uint32_t *)addr.s6_addr;
|
|
}
|
|
|
|
inline static const uint32_t *
|
|
in6_uint32_ptr(const in6_addr &addr)
|
|
{
|
|
return (uint32_t *)addr.s6_addr;
|
|
}
|
|
|
|
huint128_t
|
|
IPPacket::In6ToHUInt(in6_addr addr)
|
|
{
|
|
uint32_t *ptr = in6_uint32_ptr(addr);
|
|
#if __BYTE_ORDER == __BIG_ENDIAN
|
|
return huint128_t{ptr[0]} | (huint128_t{ptr[1]} << 32)
|
|
| (huint128_t{ptr[2]} << 64) | (huint128_t{ptr[3]} << 96);
|
|
#else
|
|
return huint128_t{ntohl(ptr[3])} | (huint128_t{ntohl(ptr[2])} << 32)
|
|
| (huint128_t{ntohl(ptr[1])} << 64)
|
|
| (huint128_t{ntohl(ptr[0])} << 96);
|
|
#endif
|
|
}
|
|
|
|
in6_addr
|
|
IPPacket::HUIntToIn6(huint128_t x)
|
|
{
|
|
in6_addr addr;
|
|
auto i = ntoh128(x.h);
|
|
memcpy(&addr, &i, 16);
|
|
return addr;
|
|
}
|
|
|
|
huint128_t
|
|
IPPacket::ExpandV4(huint32_t i)
|
|
{
|
|
huint128_t ff = {0xff};
|
|
huint128_t expanded{i.h};
|
|
return (ff << 40) | (ff << 32) | expanded;
|
|
}
|
|
|
|
huint32_t
|
|
IPPacket::TruncateV6(huint128_t i)
|
|
{
|
|
huint32_t ret = {0};
|
|
ret.h = (uint32_t)(i.h & (0x00000000ffffffffUL));
|
|
return ret;
|
|
}
|
|
|
|
huint128_t
|
|
IPPacket::srcv6() const
|
|
{
|
|
if(IsV6())
|
|
return In6ToHUInt(HeaderV6()->srcaddr);
|
|
|
|
return ExpandV4(srcv4());
|
|
}
|
|
|
|
huint128_t
|
|
IPPacket::dstv6() const
|
|
{
|
|
if(IsV6())
|
|
return In6ToHUInt(HeaderV6()->dstaddr);
|
|
|
|
return ExpandV4(dstv4());
|
|
}
|
|
|
|
bool
|
|
IPPacket::Load(const llarp_buffer_t &pkt)
|
|
{
|
|
if(pkt.sz > sizeof(buf))
|
|
return false;
|
|
sz = pkt.sz;
|
|
std::copy_n(pkt.base, sz, buf);
|
|
return true;
|
|
}
|
|
|
|
ManagedBuffer
|
|
IPPacket::ConstBuffer() const
|
|
{
|
|
const byte_t *ptr = buf;
|
|
llarp_buffer_t b(ptr, sz);
|
|
return ManagedBuffer(b);
|
|
}
|
|
|
|
ManagedBuffer
|
|
IPPacket::Buffer()
|
|
{
|
|
byte_t *ptr = buf;
|
|
llarp_buffer_t b(ptr, sz);
|
|
return ManagedBuffer(b);
|
|
}
|
|
|
|
huint32_t
|
|
IPPacket::srcv4() const
|
|
{
|
|
return huint32_t{ntohl(Header()->saddr)};
|
|
}
|
|
|
|
huint32_t
|
|
IPPacket::dstv4() const
|
|
{
|
|
return huint32_t{ntohl(Header()->daddr)};
|
|
}
|
|
|
|
#if 0
|
|
static uint32_t
|
|
ipchksum_pseudoIPv4(nuint32_t src_ip, nuint32_t dst_ip, uint8_t proto,
|
|
uint16_t innerlen)
|
|
{
|
|
#define IPCS(x) ((uint32_t)(x & 0xFFff) + (uint32_t)(x >> 16))
|
|
uint32_t sum = IPCS(src_ip.n) + IPCS(dst_ip.n) + (uint32_t)proto
|
|
+ (uint32_t)htons(innerlen);
|
|
#undef IPCS
|
|
return sum;
|
|
}
|
|
|
|
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)
|
|
{
|
|
uint16_t x = 0;
|
|
|
|
*(byte_t *)&x = *(const byte_t *)buf;
|
|
sum += x;
|
|
}
|
|
|
|
// only need to do it 2 times to be sure
|
|
// proof: 0xFFff + 0xFFff = 0x1FFfe -> 0xFFff
|
|
sum = (sum & 0xFFff) + (sum >> 16);
|
|
sum += sum >> 16;
|
|
|
|
return uint16_t((~sum) & 0xFFff);
|
|
}
|
|
#endif
|
|
|
|
#define ADD32CS(x) ((uint32_t)(x & 0xFFff) + (uint32_t)(x >> 16))
|
|
#define SUB32CS(x) ((uint32_t)((~x) & 0xFFff) + (uint32_t)((~x) >> 16))
|
|
|
|
static nuint16_t
|
|
deltaIPv4Checksum(nuint16_t old_sum, nuint32_t old_src_ip,
|
|
nuint32_t old_dst_ip, nuint32_t new_src_ip,
|
|
nuint32_t new_dst_ip)
|
|
{
|
|
uint32_t sum = uint32_t(old_sum.n) + ADD32CS(old_src_ip.n)
|
|
+ ADD32CS(old_dst_ip.n) + SUB32CS(new_src_ip.n)
|
|
+ SUB32CS(new_dst_ip.n);
|
|
|
|
// only need to do it 2 times to be sure
|
|
// proof: 0xFFff + 0xFFff = 0x1FFfe -> 0xFFff
|
|
sum = (sum & 0xFFff) + (sum >> 16);
|
|
sum += sum >> 16;
|
|
|
|
return nuint16_t{uint16_t(sum & 0xFFff)};
|
|
}
|
|
|
|
static nuint16_t
|
|
deltaIPv6Checksum(nuint16_t old_sum, const uint32_t old_src_ip[4],
|
|
const uint32_t old_dst_ip[4],
|
|
const uint32_t new_src_ip[4],
|
|
const uint32_t new_dst_ip[4])
|
|
{
|
|
/* we don't actually care in what way integers are arranged in memory
|
|
* internally */
|
|
/* as long as uint16 pairs are swapped in correct direction, result will
|
|
* be correct (assuming there are no gaps in structure) */
|
|
/* we represent 128bit stuff there as 4 32bit ints, that should be more or
|
|
* less correct */
|
|
/* we could do 64bit ints too but then we couldn't reuse 32bit macros and
|
|
* that'd suck for 32bit cpus */
|
|
#define ADDN128CS(x) \
|
|
(ADD32CS(x[0]) + ADD32CS(x[1]) + ADD32CS(x[2]) + ADD32CS(x[3]))
|
|
#define SUBN128CS(x) \
|
|
(SUB32CS(x[0]) + SUB32CS(x[1]) + SUB32CS(x[2]) + SUB32CS(x[3]))
|
|
uint32_t sum = uint32_t(old_sum.n) + ADDN128CS(old_src_ip)
|
|
+ ADDN128CS(old_dst_ip) + SUBN128CS(new_src_ip)
|
|
+ SUBN128CS(new_dst_ip);
|
|
#undef ADDN128CS
|
|
#undef SUBN128CS
|
|
|
|
// only need to do it 2 times to be sure
|
|
// proof: 0xFFff + 0xFFff = 0x1FFfe -> 0xFFff
|
|
sum = (sum & 0xFFff) + (sum >> 16);
|
|
sum += sum >> 16;
|
|
|
|
return nuint16_t{uint16_t(sum & 0xFFff)};
|
|
}
|
|
|
|
#undef ADD32CS
|
|
#undef SUB32CS
|
|
|
|
static void
|
|
deltaChecksumIPv4TCP(byte_t *pld, size_t psz, size_t fragoff,
|
|
size_t chksumoff, nuint32_t oSrcIP, nuint32_t oDstIP,
|
|
nuint32_t nSrcIP, nuint32_t nDstIP)
|
|
{
|
|
if(fragoff > chksumoff || psz < chksumoff - fragoff + 2)
|
|
return;
|
|
|
|
auto check = (nuint16_t *)(pld + chksumoff - fragoff);
|
|
|
|
*check = deltaIPv4Checksum(*check, oSrcIP, oDstIP, nSrcIP, nDstIP);
|
|
// usually, TCP checksum field cannot be 0xFFff,
|
|
// because one's complement addition cannot result in 0x0000,
|
|
// and there's inversion in the end;
|
|
// emulate that.
|
|
if(check->n == 0xFFff)
|
|
check->n = 0x0000;
|
|
}
|
|
|
|
static void
|
|
deltaChecksumIPv6TCP(byte_t *pld, size_t psz, size_t fragoff,
|
|
size_t chksumoff, const uint32_t oSrcIP[4],
|
|
const uint32_t oDstIP[4], const uint32_t nSrcIP[4],
|
|
const uint32_t nDstIP[4])
|
|
{
|
|
if(fragoff > chksumoff || psz < chksumoff - fragoff + 2)
|
|
return;
|
|
|
|
auto check = (nuint16_t *)(pld + chksumoff - fragoff);
|
|
|
|
*check = deltaIPv6Checksum(*check, oSrcIP, oDstIP, nSrcIP, nDstIP);
|
|
// usually, TCP checksum field cannot be 0xFFff,
|
|
// because one's complement addition cannot result in 0x0000,
|
|
// and there's inversion in the end;
|
|
// emulate that.
|
|
if(check->n == 0xFFff)
|
|
check->n = 0x0000;
|
|
}
|
|
|
|
static void
|
|
deltaChecksumIPv4UDP(byte_t *pld, size_t psz, size_t fragoff,
|
|
nuint32_t oSrcIP, nuint32_t oDstIP, nuint32_t nSrcIP,
|
|
nuint32_t nDstIP)
|
|
{
|
|
if(fragoff > 6 || psz < 6 + 2)
|
|
return;
|
|
|
|
auto check = (nuint16_t *)(pld + 6);
|
|
if(check->n == 0x0000)
|
|
return; // 0 is used to indicate "no checksum", don't change
|
|
|
|
*check = deltaIPv4Checksum(*check, oSrcIP, oDstIP, nSrcIP, nDstIP);
|
|
// 0 is used to indicate "no checksum"
|
|
// 0xFFff and 0 are equivalent in one's complement math
|
|
// 0xFFff + 1 = 0x10000 -> 0x0001 (same as 0 + 1)
|
|
// infact it's impossible to get 0 with such addition,
|
|
// when starting from non-0 value.
|
|
// inside deltachksum we don't invert so it's safe to skip check there
|
|
// if(check->n == 0x0000)
|
|
// check->n = 0xFFff;
|
|
}
|
|
|
|
static void
|
|
deltaChecksumIPv6UDP(byte_t *pld, size_t psz, size_t fragoff,
|
|
const uint32_t oSrcIP[4], const uint32_t oDstIP[4],
|
|
const uint32_t nSrcIP[4], const uint32_t nDstIP[4])
|
|
{
|
|
if(fragoff > 6 || psz < 6 + 2)
|
|
return;
|
|
|
|
auto check = (nuint16_t *)(pld + 6);
|
|
// 0 is used to indicate "no checksum", don't change
|
|
// even tho this shouldn't happen for IPv6, handle it properly
|
|
// we actually should drop/log 0-checksum packets per spec
|
|
// but that should be done at upper level than this function
|
|
// it's better to do correct thing there regardless
|
|
// XXX or maybe we should change this function to be able to return error?
|
|
// either way that's not a priority
|
|
if(check->n == 0x0000)
|
|
return;
|
|
|
|
*check = deltaIPv6Checksum(*check, oSrcIP, oDstIP, nSrcIP, nDstIP);
|
|
// 0 is used to indicate "no checksum"
|
|
// 0xFFff and 0 are equivalent in one's complement math
|
|
// 0xFFff + 1 = 0x10000 -> 0x0001 (same as 0 + 1)
|
|
// infact it's impossible to get 0 with such addition,
|
|
// when starting from non-0 value.
|
|
// inside deltachksum we don't invert so it's safe to skip check there
|
|
// if(check->n == 0x0000)
|
|
// check->n = 0xFFff;
|
|
}
|
|
|
|
void
|
|
IPPacket::UpdateIPv4Address(nuint32_t nSrcIP, nuint32_t nDstIP)
|
|
{
|
|
llarp::LogDebug("set src=", nSrcIP, " dst=", nDstIP);
|
|
|
|
auto hdr = Header();
|
|
|
|
auto oSrcIP = nuint32_t{hdr->saddr};
|
|
auto oDstIP = nuint32_t{hdr->daddr};
|
|
|
|
// L4 checksum
|
|
auto ihs = size_t(hdr->ihl * 4);
|
|
if(ihs <= sz)
|
|
{
|
|
auto pld = buf + ihs;
|
|
auto psz = sz - ihs;
|
|
|
|
auto fragoff = size_t((ntohs(hdr->frag_off) & 0x1Fff) * 8);
|
|
|
|
switch(hdr->protocol)
|
|
{
|
|
case 6: // TCP
|
|
deltaChecksumIPv4TCP(pld, psz, fragoff, 16, oSrcIP, oDstIP, nSrcIP,
|
|
nDstIP);
|
|
break;
|
|
case 17: // UDP
|
|
case 136: // UDP-Lite - same checksum place, same 0->0xFFff condition
|
|
deltaChecksumIPv4UDP(pld, psz, fragoff, oSrcIP, oDstIP, nSrcIP,
|
|
nDstIP);
|
|
break;
|
|
case 33: // DCCP
|
|
deltaChecksumIPv4TCP(pld, psz, fragoff, 6, oSrcIP, oDstIP, nSrcIP,
|
|
nDstIP);
|
|
break;
|
|
}
|
|
}
|
|
|
|
// IPv4 checksum
|
|
auto v4chk = (nuint16_t *)&(hdr->check);
|
|
*v4chk = deltaIPv4Checksum(*v4chk, oSrcIP, oDstIP, nSrcIP, nDstIP);
|
|
|
|
// write new IP addresses
|
|
hdr->saddr = nSrcIP.n;
|
|
hdr->daddr = nDstIP.n;
|
|
}
|
|
|
|
void
|
|
IPPacket::UpdateIPv6Address(huint128_t src, huint128_t dst)
|
|
{
|
|
const size_t ihs = 4 + 4 + 16 + 16;
|
|
|
|
// XXX should've been checked at upper level?
|
|
if(sz <= ihs)
|
|
return;
|
|
|
|
auto hdr = HeaderV6();
|
|
|
|
const auto oldSrcIP = hdr->srcaddr;
|
|
const auto oldDstIP = hdr->dstaddr;
|
|
const uint32_t *oSrcIP = in6_uint32_ptr(oldSrcIP);
|
|
const uint32_t *oDstIP = in6_uint32_ptr(oldDstIP);
|
|
|
|
// IPv6 address
|
|
hdr->srcaddr = HUIntToIn6(src);
|
|
hdr->dstaddr = HUIntToIn6(dst);
|
|
const uint32_t *nSrcIP = in6_uint32_ptr(hdr->srcaddr);
|
|
const uint32_t *nDstIP = in6_uint32_ptr(hdr->dstaddr);
|
|
|
|
// TODO IPv6 header options
|
|
auto pld = buf + ihs;
|
|
auto psz = sz - ihs;
|
|
|
|
size_t fragoff = 0;
|
|
auto nextproto = hdr->proto;
|
|
for(;;)
|
|
{
|
|
switch(nextproto)
|
|
{
|
|
case 0: // Hop-by-Hop Options
|
|
case 43: // Routing Header
|
|
case 60: // Destination Options
|
|
{
|
|
nextproto = pld[0];
|
|
auto addlen = (size_t(pld[1]) + 1) * 8;
|
|
if(psz < addlen)
|
|
return;
|
|
pld += addlen;
|
|
psz -= addlen;
|
|
break;
|
|
}
|
|
|
|
case 44: // Fragment Header
|
|
/*
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| Next Header | Reserved | Fragment Offset |Res|M|
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| Identification |
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
*/
|
|
nextproto = pld[0];
|
|
fragoff = (uint16_t(pld[2]) << 8) | (uint16_t(pld[3]) & 0xFC);
|
|
if(psz < 8)
|
|
return;
|
|
pld += 8;
|
|
psz -= 8;
|
|
|
|
// jump straight to payload processing
|
|
if(fragoff != 0)
|
|
goto endprotohdrs;
|
|
break;
|
|
|
|
default:
|
|
goto endprotohdrs;
|
|
}
|
|
}
|
|
endprotohdrs:
|
|
|
|
switch(nextproto)
|
|
{
|
|
case 6: // TCP
|
|
deltaChecksumIPv6TCP(pld, psz, fragoff, 16, oSrcIP, oDstIP, nSrcIP,
|
|
nDstIP);
|
|
break;
|
|
case 17: // UDP
|
|
case 136: // UDP-Lite - same checksum place, same 0->0xFFff condition
|
|
deltaChecksumIPv6UDP(pld, psz, fragoff, oSrcIP, oDstIP, nSrcIP,
|
|
nDstIP);
|
|
break;
|
|
case 33: // DCCP
|
|
deltaChecksumIPv6TCP(pld, psz, fragoff, 6, oSrcIP, oDstIP, nSrcIP,
|
|
nDstIP);
|
|
break;
|
|
}
|
|
}
|
|
} // namespace net
|
|
} // namespace llarp
|