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net/ip: IPv6 packet deltachecksum

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This commit is contained in:
cathugger 2019-06-11 23:52:13 +03:00
parent 6730af207f
commit e085f3e6c5
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GPG key ID: 9BADDA2DAF6F01A8
1 changed files with 47 additions and 21 deletions
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68
llarp/net/ip.cpp
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@ -188,6 +188,50 @@ namespace llarp
hdr->daddr = nDstIP.n;
}
void
IPPacket::UpdateIPv6Address(huint128_t src, huint128_t dst)
{
const size_t ihs = 40;
// XXX should've been checked at upper level?
if(sz <= ihs)
return;
auto hdr = HeaderV6();
const uint32_t oSrcIP = hdr->srcaddr;
const uint32_t oDstIP = hdr->dstaddr;
// IPv6 address
hdr->srcaddr = HUIntToIn6(src);
hdr->dstaddr = HUIntToIn6(dst);
// TODO IPv6 header options
auto pld = buf + ihs;
auto psz = sz - ihs;
switch(hdr->proto)
{
case 6: // TCP
checksumDstIPv6TCP(pld, psz, fragoff, 16, &oSrcIP.s6_addr32,
&oDstIP.s6_addr32, &hdr->srcaddr.s6_addr32,
&hdr->dstaddr.s6_addr32);
break;
case 17: // UDP
case 136: // UDP-Lite - same checksum place, same 0->0xFFff condition
checksumDstIPv6UDP(pld, psz, fragoff, &oSrcIP.s6_addr32,
&oDstIP.s6_addr32, &hdr->srcaddr.s6_addr32,
&hdr->dstaddr.s6_addr32);
break;
case 33: // DCCP
checksumDstIPv6TCP(pld, psz, fragoff, 6, &oSrcIP.s6_addr32,
&oDstIP.s6_addr32, &hdr->srcaddr.s6_addr32,
&hdr->dstaddr.s6_addr32);
break;
}
}
#define ADD32CS(x) ((uint32_t)(x & 0xFFff) + (uint32_t)(x >> 16))
#define SUB32CS(x) ((uint32_t)((~x) & 0xFFff) + (uint32_t)((~x) >> 16))
@ -238,27 +282,6 @@ namespace llarp
#undef ADD32CS
#undef SUB32CS
void
IPPacket::UpdateIPv6Address(huint128_t src, huint128_t dst)
{
if(sz <= 40)
return;
auto hdr = HeaderV6();
auto oldSrc = hdr->srcaddr;
auto oldDst = hdr->dstaddr;
hdr->srcaddr = HUIntToIn6(src);
hdr->dstaddr = HUIntToIn6(dst);
const size_t ihs = 40;
auto pld = buf + ihs;
auto psz = sz - ihs;
switch(hdr->proto)
{
//tcp
case 6:
return;
}
}
static void
deltaChecksumIPv4TCP(byte_t *pld, ABSL_ATTRIBUTE_UNUSED size_t psz,
@ -299,6 +322,7 @@ namespace llarp
check->n = 0x0000;
}
static void
deltaChecksumIPv4UDP(byte_t *pld, ABSL_ATTRIBUTE_UNUSED size_t psz,
size_t fragoff, nuint32_t oSrcIP, nuint32_t oDstIP,
@ -337,6 +361,8 @@ namespace llarp
// 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;