lokinet/llarp/iwp_link.cpp
2018-06-21 20:25:51 -04:00

1973 lines
47 KiB
C++

#include <llarp/crypto_async.h>
#include <llarp/iwp.h>
#include <llarp/net.h>
#include <llarp/time.h>
#include <llarp/crypto.hpp>
#include "address_info.hpp"
#include "link/encoder.hpp"
#include <sodium/crypto_sign_ed25519.h>
#include <algorithm>
#include <bitset>
#include <cassert>
#include <fstream>
#include <list>
#include <map>
#include <mutex>
#include <queue>
#include <set>
#include <unordered_map>
#include <vector>
#include "buffer.hpp"
#include "fs.hpp"
#include "logger.hpp"
#include "mem.hpp"
#include "net.hpp"
#include "router.hpp"
#include "str.hpp"
namespace iwp
{
// session activity timeout is 10s
constexpr llarp_time_t SESSION_TIMEOUT = 10000;
constexpr size_t MAX_PAD = 128;
enum msgtype
{
eALIV = 0x00,
eXMIT = 0x01,
eACKS = 0x02,
eFRAG = 0x03
};
struct sendbuf_t
{
sendbuf_t(size_t s) : sz(s)
{
buf = new byte_t[s];
}
~sendbuf_t()
{
delete[] buf;
}
byte_t *buf;
size_t sz;
size_t
size() const
{
return sz;
}
byte_t *
data()
{
return buf;
}
};
enum header_flag
{
eSessionInvalidated = (1 << 0),
eHighPacketDrop = (1 << 1),
eHighMTUDetected = (1 << 2),
eProtoUpgrade = (1 << 3)
};
/** plaintext frame header */
struct frame_header
{
byte_t *ptr;
frame_header(byte_t *buf) : ptr(buf)
{
}
byte_t *
data()
{
return ptr + 6;
}
uint8_t &
version()
{
return ptr[0];
}
uint8_t &
msgtype()
{
return ptr[1];
}
uint16_t
size() const
{
uint16_t sz;
memcpy(&sz, ptr + 2, 2);
return sz;
}
void
setsize(uint16_t sz)
{
memcpy(ptr + 2, &sz, 2);
}
uint8_t &
flags()
{
return ptr[5];
}
void
setflag(header_flag f)
{
ptr[5] |= f;
}
};
byte_t *
init_sendbuf(sendbuf_t *buf, msgtype t, uint16_t sz, uint8_t flags)
{
frame_header hdr(buf->data());
hdr.version() = 0;
hdr.msgtype() = t;
hdr.setsize(sz);
buf->data()[4] = 0;
buf->data()[5] = flags;
return hdr.data();
}
/** xmit header */
struct xmit
{
byte_t buffer[48];
xmit() = default;
xmit(byte_t *ptr)
{
memcpy(buffer, ptr, sizeof(buffer));
}
xmit(const xmit &other)
{
memcpy(buffer, other.buffer, sizeof(buffer));
}
void
set_info(const byte_t *hash, uint64_t id, uint16_t fragsz, uint16_t lastsz,
uint8_t numfrags, uint8_t flags = 0x01)
{
// big endian assumed
// TODO: implement little endian
memcpy(buffer, hash, 32);
memcpy(buffer + 32, &id, 8);
memcpy(buffer + 40, &fragsz, 2);
memcpy(buffer + 42, &lastsz, 2);
buffer[44] = 0;
buffer[45] = 0;
buffer[46] = numfrags;
buffer[47] = flags;
}
const byte_t *
hash() const
{
return &buffer[0];
}
uint64_t
msgid() const
{
// big endian assumed
// TODO: implement little endian
const byte_t *start = buffer + 32;
const uint64_t *msgid = (const uint64_t *)start;
return *msgid;
}
// size of each full fragment
uint16_t
fragsize() const
{
// big endian assumed
// TODO: implement little endian
const byte_t *start = buffer + 40;
const uint16_t *fragsz = (uint16_t *)start;
return *fragsz;
}
// number of full fragments
uint8_t
numfrags() const
{
return buffer[46];
}
// size of the entire message
size_t
totalsize() const
{
return (fragsize() * numfrags()) + lastfrag();
}
// size of the last fragment
uint16_t
lastfrag() const
{
// big endian assumed
// TODO: implement little endian
const byte_t *start = buffer + 42;
const uint16_t *lastsz = (uint16_t *)start;
return *lastsz;
}
uint8_t
flags()
{
return buffer[47];
}
};
// forward declare
struct session;
struct server;
struct transit_message
{
xmit msginfo;
std::bitset< 32 > status = {};
typedef std::vector< byte_t > fragment_t;
std::unordered_map< byte_t, fragment_t > frags;
fragment_t lastfrag;
void
clear()
{
frags.clear();
lastfrag.clear();
}
// calculate acked bitmask
uint32_t
get_bitmask() const
{
uint32_t bitmask = 0;
uint8_t idx = 0;
while(idx < 32)
{
bitmask |= (status.test(idx) ? (1 << idx) : 0);
++idx;
}
return bitmask;
}
// outbound
transit_message(llarp_buffer_t buf, const byte_t *hash, uint64_t id,
uint16_t mtu = 1024)
{
put_message(buf, hash, id, mtu);
}
// inbound
transit_message(const xmit &x) : msginfo(x)
{
byte_t fragidx = 0;
uint16_t fragsize = x.fragsize();
while(fragidx < x.numfrags())
{
frags[fragidx].resize(fragsize);
++fragidx;
}
status.reset();
}
/// ack packets based off a bitmask
void
ack(uint32_t bitmask)
{
uint8_t idx = 0;
while(idx < 32)
{
if(bitmask & (1 << idx))
{
status.set(idx);
}
++idx;
}
}
bool
should_send_ack() const
{
if(msginfo.numfrags() == 0)
return true;
return status.count() % (1 + (msginfo.numfrags() / 2)) == 0;
}
bool
completed() const
{
for(byte_t idx = 0; idx < msginfo.numfrags(); ++idx)
{
if(!status.test(idx))
return false;
}
return true;
}
template < typename T >
void
generate_xmit(T &queue, byte_t flags = 0)
{
uint16_t sz = lastfrag.size() + sizeof(msginfo.buffer);
queue.push(new sendbuf_t(sz + 6));
auto body_ptr = init_sendbuf(queue.back(), eXMIT, sz, flags);
memcpy(body_ptr, msginfo.buffer, sizeof(msginfo.buffer));
body_ptr += sizeof(msginfo.buffer);
memcpy(body_ptr, lastfrag.data(), lastfrag.size());
}
template < typename T >
void
retransmit_frags(T &queue, byte_t flags = 0)
{
auto msgid = msginfo.msgid();
auto fragsize = msginfo.fragsize();
for(auto &frag : frags)
{
if(status.test(frag.first))
continue;
uint16_t sz = 9 + fragsize;
queue.push(new sendbuf_t(sz + 6));
auto body_ptr = init_sendbuf(queue.back(), eFRAG, sz, flags);
// TODO: assumes big endian
memcpy(body_ptr, &msgid, 8);
body_ptr[8] = frag.first;
memcpy(body_ptr + 9, frag.second.data(), fragsize);
}
}
bool
reassemble(std::vector< byte_t > &buffer)
{
auto total = msginfo.totalsize();
buffer.resize(total);
auto fragsz = msginfo.fragsize();
auto ptr = &buffer[0];
for(byte_t idx = 0; idx < msginfo.numfrags(); ++idx)
{
if(!status.test(idx))
return false;
memcpy(ptr, frags[idx].data(), fragsz);
ptr += fragsz;
}
memcpy(ptr, lastfrag.data(), lastfrag.size());
return true;
}
void
put_message(llarp_buffer_t buf, const byte_t *hash, uint64_t id,
uint16_t mtu = 1024)
{
status.reset();
uint8_t fragid = 0;
uint16_t fragsize = mtu;
size_t left = buf.sz;
while(left > fragsize)
{
auto &frag = frags[fragid];
frag.resize(fragsize);
memcpy(frag.data(), buf.cur, fragsize);
buf.cur += fragsize;
fragid++;
left -= fragsize;
}
uint16_t lastfrag = buf.sz - (buf.cur - buf.base);
// set info for xmit
msginfo.set_info(hash, id, fragsize, lastfrag, fragid);
put_lastfrag(buf.cur, lastfrag);
}
void
put_lastfrag(byte_t *buf, size_t sz)
{
lastfrag.resize(sz);
memcpy(lastfrag.data(), buf, sz);
}
bool
put_frag(byte_t fragno, byte_t *buf)
{
auto itr = frags.find(fragno);
if(itr == frags.end())
return false;
memcpy(itr->second.data(), buf, msginfo.fragsize());
status.set(fragno);
return true;
}
};
struct frame_state
{
byte_t rxflags = 0;
byte_t txflags = 0;
uint64_t rxids = 0;
uint64_t txids = 0;
llarp_time_t lastEvent = 0;
std::unordered_map< uint64_t, transit_message * > rx;
std::unordered_map< uint64_t, transit_message * > tx;
typedef std::queue< sendbuf_t * > sendqueue_t;
llarp_router *router = nullptr;
llarp_link_session *parent = nullptr;
sendqueue_t sendqueue;
/// return true if both sides have the same state flags
bool
flags_agree(byte_t flags) const
{
return ((rxflags & flags) & (txflags & flags)) == flags;
}
void
clear()
{
auto _rx = rx;
auto _tx = tx;
for(auto &item : _rx)
delete item.second;
for(auto &item : _tx)
delete item.second;
rx.clear();
tx.clear();
}
bool
inbound_frame_complete(uint64_t id);
void
push_ackfor(uint64_t id, uint32_t bitmask)
{
llarp::Debug("ACK for msgid=", id, " mask=", bitmask);
sendqueue.push(new sendbuf_t(12 + 6));
auto body_ptr = init_sendbuf(sendqueue.back(), eACKS, 12, txflags);
// TODO: this assumes big endian
memcpy(body_ptr, &id, 8);
memcpy(body_ptr + 8, &bitmask, 4);
}
bool
got_xmit(frame_header hdr, size_t sz)
{
if(hdr.size() > sz)
{
// overflow
llarp::Warn("invalid XMIT frame size ", hdr.size(), " > ", sz);
return false;
}
sz = hdr.size();
// extract xmit data
xmit x(hdr.data());
const auto bufsz = sizeof(x.buffer);
if(sz - bufsz < x.lastfrag())
{
// bad size of last fragment
llarp::Warn("XMIT frag size missmatch ", sz - bufsz, " < ",
x.lastfrag());
return false;
}
// check LSB set on flags
if(x.flags() & 0x01)
{
auto id = x.msgid();
auto itr = rx.find(id);
if(itr == rx.end())
{
auto msg = new transit_message(x);
rx[id] = msg;
llarp::Debug("got message XMIT with ", (int)x.numfrags(),
" fragments");
// inserted, put last fragment
msg->put_lastfrag(hdr.data() + sizeof(x.buffer), x.lastfrag());
push_ackfor(id, 0);
if(x.numfrags() == 0)
{
return inbound_frame_complete(id);
}
return true;
}
else
llarp::Warn("duplicate XMIT msgid=", x.msgid());
}
else
llarp::Warn("LSB not set on flags");
return false;
}
void
alive()
{
lastEvent = llarp_time_now_ms();
}
bool
got_frag(frame_header hdr, size_t sz)
{
if(hdr.size() > sz)
{
// overflow
llarp::Warn("invalid FRAG frame size ", hdr.size(), " > ", sz);
return false;
}
sz = hdr.size();
if(sz <= 9)
{
// underflow
llarp::Warn("invalid FRAG frame size ", sz, " <= 9");
return false;
}
uint64_t msgid;
byte_t fragno;
// assumes big endian
// TODO: implement little endian
memcpy(&msgid, hdr.data(), 8);
memcpy(&fragno, hdr.data() + 8, 1);
auto itr = rx.find(msgid);
if(itr == rx.end())
{
llarp::Warn("no such RX fragment, msgid=", msgid);
return false;
}
auto fragsize = itr->second->msginfo.fragsize();
if(fragsize != sz - 9)
{
llarp::Warn("RX fragment size missmatch ", fragsize, " != ", sz - 9);
return false;
}
llarp::Debug("RX got fragment ", (int)fragno, " msgid=", msgid);
if(!itr->second->put_frag(fragno, hdr.data() + 9))
{
llarp::Warn("inbound message does not have fragment msgid=", msgid,
" fragno=", (int)fragno);
return false;
}
auto mask = itr->second->get_bitmask();
if(itr->second->completed())
{
push_ackfor(msgid, mask);
return inbound_frame_complete(msgid);
}
else if(itr->second->should_send_ack())
{
push_ackfor(msgid, mask);
}
return true;
}
bool
got_acks(frame_header hdr, size_t sz);
// queue new outbound message
void
queue_tx(uint64_t id, transit_message *msg)
{
tx.insert(std::make_pair(id, msg));
msg->generate_xmit(sendqueue, txflags);
}
void
retransmit()
{
for(auto &item : tx)
{
item.second->retransmit_frags(sendqueue, txflags);
}
}
// get next frame to encrypt and transmit
bool
next_frame(llarp_buffer_t *buf)
{
auto left = sendqueue.size();
llarp::Debug("next frame, ", left, " frames left in send queue");
if(left)
{
sendbuf_t *send = sendqueue.front();
buf->base = send->data();
buf->cur = send->data();
buf->sz = send->size();
return true;
}
return false;
}
void
pop_next_frame()
{
sendbuf_t *buf = sendqueue.front();
sendqueue.pop();
delete buf;
}
bool
process(byte_t *buf, size_t sz)
{
frame_header hdr(buf);
if(hdr.flags() & eSessionInvalidated)
{
rxflags |= eSessionInvalidated;
}
switch(hdr.msgtype())
{
case eALIV:
if(rxflags & eSessionInvalidated)
{
txflags |= eSessionInvalidated;
}
return true;
case eXMIT:
return got_xmit(hdr, sz - 6);
case eACKS:
return got_acks(hdr, sz - 6);
case eFRAG:
return got_frag(hdr, sz - 6);
default:
return false;
}
}
};
struct session
{
llarp_udp_io *udp;
llarp_crypto *crypto;
llarp_async_iwp *iwp;
llarp_logic *logic;
llarp_link_session *parent = nullptr;
server *serv = nullptr;
llarp_rc *our_router = nullptr;
llarp_rc remote_router;
llarp::SecretKey eph_seckey;
llarp::PubKey remote;
llarp::SharedSecret sessionkey;
llarp_link_establish_job *establish_job = nullptr;
uint32_t establish_job_id = 0;
uint32_t frames = 0;
bool working = false;
llarp::Addr addr;
iwp_async_intro intro;
iwp_async_introack introack;
iwp_async_session_start start;
frame_state frame;
byte_t token[32];
byte_t workbuf[MAX_PAD + 128];
enum State
{
eInitial,
eIntroRecv,
eIntroSent,
eIntroAckSent,
eIntroAckRecv,
eSessionStartSent,
eLIMSent,
eEstablished,
eTimeout
};
State state;
session(llarp_udp_io *u, llarp_async_iwp *i, llarp_crypto *c,
llarp_logic *l, const byte_t *seckey, const llarp::Addr &a)
: udp(u), crypto(c), iwp(i), logic(l), addr(a), state(eInitial)
{
eph_seckey = seckey;
llarp::Zero(&remote_router, sizeof(llarp_rc));
crypto->randbytes(token, 32);
}
~session()
{
llarp_rc_free(&remote_router);
frame.clear();
}
static llarp_rc *
get_remote_router(llarp_link_session *s)
{
session *self = static_cast< session * >(s->impl);
return &self->remote_router;
}
static bool
sendto(llarp_link_session *s, llarp_buffer_t msg)
{
session *self = static_cast< session * >(s->impl);
auto id = self->frame.txids++;
llarp::ShortHash digest;
self->crypto->shorthash(digest, msg);
transit_message *m = new transit_message(msg, digest, id);
self->add_outbound_message(id, m);
return true;
}
void
add_outbound_message(uint64_t id, transit_message *msg)
{
llarp::Debug("add outbound message ", id, " of size ",
msg->msginfo.totalsize(),
" numfrags=", (int)msg->msginfo.numfrags(),
" lastfrag=", (int)msg->msginfo.lastfrag());
frame.queue_tx(id, msg);
pump();
}
static void
handle_invalidate_timer(void *user);
bool
CheckRCValid()
{
// verify signatuire
if(!llarp_rc_verify_sig(crypto, &remote_router))
return false;
auto &list = remote_router.addrs->list;
if(list.size() == 0) // the remote node is a client node so accept it
return true;
// check if the RC owns a pubkey that we are using
for(auto &ai : list)
{
if(memcmp(ai.enc_key, remote, PUBKEYSIZE) == 0)
return true;
}
return false;
}
void
pump()
{
llarp_buffer_t buf;
while(frame.next_frame(&buf))
{
encrypt_frame_async_send(buf.base, buf.sz);
frame.pop_next_frame();
}
}
// this is called from net thread
void
recv(const void *buf, size_t sz)
{
switch(state)
{
case eInitial:
// got intro
on_intro(buf, sz);
return;
case eIntroSent:
// got intro ack
on_intro_ack(buf, sz);
return;
case eIntroAckSent:
// probably a session start
on_session_start(buf, sz);
return;
case eSessionStartSent:
case eLIMSent:
case eEstablished:
// session is started
decrypt_frame(buf, sz);
default:
// invalid state?
return;
}
}
static void
handle_verify_session_start(iwp_async_session_start *s);
void
send_LIM()
{
llarp::Debug("send LIM");
llarp::ShortHash digest;
// 64 bytes overhead for link message
byte_t tmp[MAX_RC_SIZE + 64];
auto buf = llarp::StackBuffer< decltype(tmp) >(tmp);
// return a llarp_buffer_t of encoded link message
if(llarp::EncodeLIM(&buf, our_router))
{
// rewind message buffer
buf.sz = buf.cur - buf.base;
buf.cur = buf.base;
// hash message buffer
crypto->shorthash(digest, buf);
auto id = frame.txids++;
auto msg = new transit_message(buf, digest, id);
// put into outbound send queue
add_outbound_message(id, msg);
EnterState(eLIMSent);
}
else
llarp::Error("LIM Encode failed");
}
static void
send_keepalive(void *user);
// return true if we should be removed
bool
Tick(uint64_t now)
{
if(timedout(now, SESSION_TIMEOUT))
{
// we are timed out
// when we are done doing stuff with all of our frames from the crypto
// workers we are done
llarp::Debug(addr, " timed out with ", frames, " frames left");
if(working)
return false;
return frames == 0;
}
if(is_invalidated())
{
// both sides agreeed to session invalidation
// terminate our session when all of our frames from the crypto workers
// are done
llarp::Debug(addr, " invaldiated session with ", frames,
" frames left");
if(working)
return false;
return frames == 0;
}
// send keepalive if we are established or a session is made
if(state == eEstablished || state == eLIMSent)
send_keepalive(this);
// pump frames
if(state == eEstablished)
{
frame.retransmit();
pump();
}
// TODO: determine if we are too idle
return false;
}
bool
IsEstablished()
{
return state == eEstablished;
}
void
session_established();
void
on_session_start(const void *buf, size_t sz)
{
if(sz > sizeof(workbuf))
{
llarp::Debug("session start too big");
return;
}
// own the buffer
memcpy(workbuf, buf, sz);
// verify session start
start.buf = workbuf;
start.sz = sz;
start.nonce = workbuf + 32;
start.token = token;
start.remote_pubkey = remote;
start.secretkey = eph_seckey;
start.sessionkey = sessionkey;
start.user = this;
start.hook = &handle_verify_session_start;
working = true;
iwp_call_async_verify_session_start(iwp, &start);
}
bool
timedout(llarp_time_t now, llarp_time_t timeout = SESSION_TIMEOUT)
{
auto diff = now - frame.lastEvent;
return diff >= timeout;
}
static bool
is_timedout(llarp_link_session *s)
{
auto now = llarp_time_now_ms();
return static_cast< session * >(s->impl)->timedout(now);
}
static void
handle_session_established(void *user)
{
session *impl = static_cast< session * >(user);
impl->session_established();
}
static void
set_established(llarp_link_session *s)
{
session *impl = static_cast< session * >(s->impl);
llarp_logic_queue_job(impl->logic, {impl, &handle_session_established});
}
static void
close(llarp_link_session *s)
{
session *impl = static_cast< session * >(s->impl);
// set our side invalidated and close async when the other side also marks
// as session invalidated
impl->frame.txflags |= eSessionInvalidated;
// TODO: add timer for session invalidation
llarp_logic_queue_job(impl->logic, {impl, &send_keepalive});
}
static void
handle_verify_introack(iwp_async_introack *introack);
static void
handle_generated_session_start(iwp_async_session_start *start)
{
session *link = static_cast< session * >(start->user);
link->working = false;
if(llarp_ev_udp_sendto(link->udp, link->addr, start->buf, start->sz)
== -1)
llarp::Error("sendto failed");
link->EnterState(eSessionStartSent);
}
bool
is_invalidated() const
{
return frame.flags_agree(eSessionInvalidated);
}
void
session_start()
{
size_t w2sz = rand() % MAX_PAD;
start.buf = workbuf;
start.sz = w2sz + (32 * 3);
start.nonce = workbuf + 32;
crypto->randbytes(start.nonce, 32);
start.token = token;
memcpy(start.buf + 64, token, 32);
if(w2sz)
crypto->randbytes(start.buf + (32 * 3), w2sz);
start.remote_pubkey = remote;
start.secretkey = eph_seckey;
start.sessionkey = sessionkey;
start.user = this;
start.hook = &handle_generated_session_start;
working = true;
iwp_call_async_gen_session_start(iwp, &start);
}
static void
handle_frame_decrypt(iwp_async_frame *frame)
{
session *self = static_cast< session * >(frame->user);
llarp::Debug("rx ", frame->sz, " frames=", self->frames);
self->frames--;
if(frame->success)
{
if(self->frame.process(frame->buf + 64, frame->sz - 64))
{
self->frame.alive();
self->pump();
}
else
llarp::Error("invalid frame from ", self->addr);
}
else
llarp::Error("decrypt frame fail from ", self->addr);
}
void
decrypt_frame(const void *buf, size_t sz)
{
if(sz > 64)
{
iwp_async_frame *frame = alloc_frame(buf, sz);
frame->hook = &handle_frame_decrypt;
iwp_call_async_frame_decrypt(iwp, frame);
}
else
llarp::Warn("short packet of ", sz, " bytes");
}
static void
handle_frame_encrypt(iwp_async_frame *frame)
{
session *self = static_cast< session * >(frame->user);
llarp::Debug("tx ", frame->sz, " frames=", self->frames);
if(llarp_ev_udp_sendto(self->udp, self->addr, frame->buf, frame->sz)
== -1)
llarp::Warn("sendto failed");
self->frames--;
}
iwp_async_frame *
alloc_frame(const void *buf, size_t sz)
{
// TODO don't hard code 1500
if(sz > 1500)
return nullptr;
iwp_async_frame *frame = new iwp_async_frame();
if(buf)
memcpy(frame->buf, buf, sz);
frame->sz = sz;
frame->user = this;
frame->sessionkey = sessionkey;
frames++;
return frame;
}
void
encrypt_frame_async_send(const void *buf, size_t sz)
{
// 64 bytes frame overhead for nonce and hmac
iwp_async_frame *frame = alloc_frame(nullptr, sz + 64);
memcpy(frame->buf + 64, buf, sz);
auto padding = rand() % MAX_PAD;
if(padding)
crypto->randbytes(frame->buf + 64 + sz, padding);
frame->sz += padding;
frame->hook = &handle_frame_encrypt;
iwp_call_async_frame_encrypt(iwp, frame);
}
static void
handle_verify_intro(iwp_async_intro *intro);
static void
handle_introack_generated(iwp_async_introack *i);
void
intro_ack()
{
uint16_t w1sz = rand() % MAX_PAD;
introack.buf = workbuf;
introack.sz = (32 * 3) + w1sz;
// randomize padding
if(w1sz)
crypto->randbytes(introack.buf + (32 * 3), w1sz);
// randomize nonce
introack.nonce = introack.buf + 32;
crypto->randbytes(introack.nonce, 32);
// token
introack.token = token;
// keys
introack.remote_pubkey = remote;
introack.secretkey = eph_seckey;
// call
introack.user = this;
introack.hook = &handle_introack_generated;
working = true;
iwp_call_async_gen_introack(iwp, &introack);
}
void
on_intro(const void *buf, size_t sz)
{
if(sz >= sizeof(workbuf))
{
// too big?
llarp::Error("intro too big");
delete this;
return;
}
// copy so we own it
memcpy(workbuf, buf, sz);
intro.buf = workbuf;
intro.sz = sz;
// give secret key
intro.secretkey = eph_seckey;
// and nonce
intro.nonce = intro.buf + 32;
intro.user = this;
// set call back hook
intro.hook = &handle_verify_intro;
// put remote pubkey into this buffer
intro.remote_pubkey = remote;
// call
EnterState(eIntroRecv);
working = true;
iwp_call_async_verify_intro(iwp, &intro);
}
void
on_intro_ack(const void *buf, size_t sz);
static llarp_link *
get_parent(llarp_link_session *s);
static void
handle_generated_intro(iwp_async_intro *i)
{
session *link = static_cast< session * >(i->user);
link->working = false;
if(i->buf)
{
llarp::Debug("send intro");
if(llarp_ev_udp_sendto(link->udp, link->addr, i->buf, i->sz) == -1)
{
llarp::Warn("send intro failed");
return;
}
link->EnterState(eIntroSent);
}
else
{
llarp::Warn("failed to generate intro");
}
}
static void
handle_establish_timeout(void *user, uint64_t orig, uint64_t left);
void
introduce(uint8_t *pub)
{
memcpy(remote, pub, 32);
intro.buf = workbuf;
size_t w0sz = (rand() % MAX_PAD);
intro.sz = (32 * 3) + w0sz;
// randomize w0
if(w0sz)
{
crypto->randbytes(intro.buf + (32 * 3), w0sz);
}
intro.nonce = intro.buf + 32;
intro.secretkey = eph_seckey;
// copy in pubkey
intro.remote_pubkey = remote;
// randomize nonce
crypto->randbytes(intro.nonce, 32);
// async generate intro packet
intro.user = this;
intro.hook = &handle_generated_intro;
working = true;
iwp_call_async_gen_intro(iwp, &intro);
// start introduce timer
establish_job_id = llarp_logic_call_later(
logic, {5000, this, &handle_establish_timeout});
}
// handle session being over
// called right before deallocation
void
done();
void
EnterState(State st)
{
frame.alive();
state = st;
}
};
struct server
{
typedef std::mutex mtx_t;
typedef std::lock_guard< mtx_t > lock_t;
llarp_router *router;
llarp_logic *logic;
llarp_crypto *crypto;
llarp_ev_loop *netloop;
llarp_async_iwp *iwp;
llarp_link *parent = nullptr;
llarp_udp_io udp;
llarp::Addr addr;
char keyfile[255];
uint32_t timeout_job_id;
typedef std::unordered_map< llarp::Addr, llarp_link_session,
llarp::addrhash >
LinkMap_t;
LinkMap_t m_sessions;
mtx_t m_sessions_Mutex;
typedef std::unordered_map< llarp::PubKey, llarp::Addr, llarp::PubKeyHash >
SessionMap_t;
SessionMap_t m_Connected;
mtx_t m_Connected_Mutex;
llarp::SecretKey seckey;
server(llarp_router *r, llarp_crypto *c, llarp_logic *l,
llarp_threadpool *w)
{
router = r;
crypto = c;
logic = l;
iwp = llarp_async_iwp_new(crypto, logic, w);
}
~server()
{
llarp_async_iwp_free(iwp);
}
// set that src address has identity pubkey
void
MapAddr(const llarp::Addr &src, const llarp::PubKey &identity)
{
lock_t lock(m_Connected_Mutex);
m_Connected[identity] = src;
}
static bool
HasSessionToRouter(llarp_link *l, const byte_t *pubkey)
{
server *serv = static_cast< server * >(l->impl);
llarp::PubKey pk(pubkey);
lock_t lock(serv->m_Connected_Mutex);
return serv->m_Connected.find(pk) != serv->m_Connected.end();
}
void
TickSessions()
{
auto now = llarp_time_now_ms();
{
lock_t lock(m_sessions_Mutex);
std::set< llarp::Addr > remove;
for(auto &itr : m_sessions)
{
session *s = static_cast< session * >(itr.second.impl);
if(s && s->Tick(now))
remove.insert(itr.first);
}
for(const auto &addr : remove)
RemoveSessionByAddr(addr);
}
}
static bool
SendToSession(llarp_link *l, const byte_t *pubkey, llarp_buffer_t buf)
{
server *serv = static_cast< server * >(l->impl);
{
lock_t lock(serv->m_Connected_Mutex);
auto itr = serv->m_Connected.find(pubkey);
if(itr != serv->m_Connected.end())
{
lock_t innerlock(serv->m_sessions_Mutex);
auto inner_itr = serv->m_sessions.find(itr->second);
if(inner_itr != serv->m_sessions.end())
{
llarp_link_session *link = &inner_itr->second;
return link->sendto(link, buf);
}
}
}
return false;
}
void
UnmapAddr(const llarp::Addr &src)
{
lock_t lock(m_Connected_Mutex);
// std::unordered_map< llarp::pubkey, llarp::Addr, llarp::pubkeyhash >
auto itr = std::find_if(
m_Connected.begin(), m_Connected.end(),
[src](const std::pair< llarp::PubKey, llarp::Addr > &item) -> bool {
return src == item.second;
});
if(itr == std::end(m_Connected))
return;
// tell router we are done with this session
router->SessionClosed(itr->first);
m_Connected.erase(itr);
}
session *
create_session(const llarp::Addr &src)
{
auto s = new session(&udp, iwp, crypto, logic, seckey, src);
s->serv = this;
return s;
}
bool
has_session_to(const llarp::Addr &dst)
{
lock_t lock(m_sessions_Mutex);
return m_sessions.find(dst) != m_sessions.end();
}
session *
find_session(const llarp::Addr &addr)
{
lock_t lock(m_sessions_Mutex);
auto itr = m_sessions.find(addr);
if(itr == m_sessions.end())
return nullptr;
else
return static_cast< session * >(itr->second.impl);
}
void
put_session(const llarp::Addr &src, session *impl)
{
llarp_link_session s = {};
s.impl = impl;
s.sendto = &session::sendto;
s.timeout = &session::is_timedout;
s.close = &session::close;
s.get_remote_router = &session::get_remote_router;
s.established = &session::set_established;
s.get_parent = &session::get_parent;
{
lock_t lock(m_sessions_Mutex);
m_sessions[src] = s;
impl->parent = &m_sessions[src];
}
impl->frame.router = router;
impl->frame.parent = impl->parent;
impl->our_router = &router->rc;
}
void
clear_sessions()
{
lock_t lock(m_sessions_Mutex);
auto itr = m_sessions.begin();
while(itr != m_sessions.end())
{
session *s = static_cast< session * >(itr->second.impl);
delete s;
itr = m_sessions.erase(itr);
}
}
void
RemoveSessionByAddr(const llarp::Addr &addr)
{
auto itr = m_sessions.find(addr);
if(itr != m_sessions.end())
{
llarp::Debug("removing session ", addr);
UnmapAddr(addr);
session *s = static_cast< session * >(itr->second.impl);
s->done();
m_sessions.erase(itr);
if(s->frames)
{
llarp::Warn("session has ", s->frames,
" left but is idle, not deallocating session so we "
"leak but don't die");
}
else
delete s;
}
}
uint8_t *
pubkey()
{
return llarp::seckey_topublic(seckey);
}
bool
ensure_privkey()
{
llarp::Debug("ensure transport private key at ", keyfile);
std::error_code ec;
if(!fs::exists(keyfile, ec))
{
if(!keygen(keyfile))
return false;
}
std::ifstream f(keyfile);
if(f.is_open())
{
f.read((char *)seckey.data(), seckey.size());
return true;
}
return false;
}
bool
keygen(const char *fname)
{
crypto->encryption_keygen(seckey);
llarp::Info("new transport key generated");
std::ofstream f(fname);
if(f.is_open())
{
f.write((char *)seckey.data(), seckey.size());
return true;
}
return false;
}
static void
handle_cleanup_timer(void *l, uint64_t orig, uint64_t left)
{
if(left)
return;
server *link = static_cast< server * >(l);
link->timeout_job_id = 0;
link->TickSessions();
// TODO: exponential backoff for cleanup timer ?
link->issue_cleanup_timer(orig);
}
// this is called in net threadpool
static void
handle_recvfrom(struct llarp_udp_io *udp, const struct sockaddr *saddr,
const void *buf, ssize_t sz)
{
server *link = static_cast< server * >(udp->user);
session *s = link->find_session(*saddr);
if(s == nullptr)
{
// new inbound session
s = link->create_session(*saddr);
}
s->recv(buf, sz);
}
void
cancel_timer()
{
if(timeout_job_id)
{
llarp_logic_cancel_call(logic, timeout_job_id);
}
timeout_job_id = 0;
}
void
issue_cleanup_timer(uint64_t timeout)
{
timeout_job_id = llarp_logic_call_later(
logic, {timeout, this, &server::handle_cleanup_timer});
}
};
bool
frame_state::inbound_frame_complete(uint64_t id)
{
bool success = false;
std::vector< byte_t > msg;
auto rxmsg = rx[id];
if(rxmsg->reassemble(msg))
{
llarp::ShortHash digest;
auto buf = llarp::Buffer< decltype(msg) >(msg);
router->crypto.shorthash(digest, buf);
if(memcmp(digest, rxmsg->msginfo.hash(), 32))
{
llarp::Warn("message hash missmatch ",
llarp::AlignedBuffer< 32 >(digest),
" != ", llarp::AlignedBuffer< 32 >(rxmsg->msginfo.hash()));
return false;
}
session *impl = static_cast< session * >(parent->impl);
success = router->HandleRecvLinkMessage(parent, buf);
if(success)
{
if(id == 0)
{
if(impl->CheckRCValid())
{
if(!impl->IsEstablished())
{
impl->send_LIM();
impl->session_established();
}
}
else
{
llarp::PubKey k = impl->remote_router.pubkey;
llarp::Warn("spoofed LIM from ", k);
impl->parent->close(impl->parent);
success = false;
}
}
}
if(!success)
llarp::Warn("failed to handle inbound message ", id);
}
else
{
llarp::Warn("failed to reassemble message ", id);
}
delete rxmsg;
rx.erase(id);
return success;
} // namespace iwp
void
session::handle_verify_intro(iwp_async_intro *intro)
{
session *self = static_cast< session * >(intro->user);
self->working = false;
if(!intro->buf)
{
llarp::Error("intro verify failed from ", self->addr, " via ",
self->serv->addr);
delete self;
return;
}
self->intro_ack();
}
void
session::session_established()
{
llarp::RouterID remote = remote_router.pubkey;
llarp::Info("session to ", remote, " established");
EnterState(eEstablished);
serv->MapAddr(addr, remote_router.pubkey);
llarp_logic_cancel_call(logic, establish_job_id);
}
void
session::done()
{
if(establish_job_id)
{
llarp_logic_remove_call(logic, establish_job_id);
handle_establish_timeout(this, 0, 0);
}
}
void
session::on_intro_ack(const void *buf, size_t sz)
{
if(sz >= sizeof(workbuf))
{
// too big?
llarp::Error("introack too big");
serv->RemoveSessionByAddr(addr);
return;
}
// copy buffer so we own it
memcpy(workbuf, buf, sz);
// set intro ack parameters
introack.buf = workbuf;
introack.sz = sz;
introack.nonce = workbuf + 32;
introack.remote_pubkey = remote;
introack.token = token;
introack.secretkey = eph_seckey;
introack.user = this;
introack.hook = &handle_verify_introack;
// async verify
working = true;
iwp_call_async_verify_introack(iwp, &introack);
}
void
session::send_keepalive(void *user)
{
session *self = static_cast< session * >(user);
// if both sides agree on invalidation
if(self->is_invalidated())
{
// don't send keepalive
return;
}
// all zeros means keepalive
byte_t tmp[8] = {0};
// set flags for tx
frame_header hdr(tmp);
hdr.flags() = self->frame.txflags;
// send frame after encrypting
auto buf = llarp::StackBuffer< decltype(tmp) >(tmp);
self->encrypt_frame_async_send(buf.base, buf.sz);
}
bool
frame_state::got_acks(frame_header hdr, size_t sz)
{
if(hdr.size() > sz)
{
llarp::Error("invalid ACKS frame size ", hdr.size(), " > ", sz);
return false;
}
sz = hdr.size();
if(sz < 12)
{
llarp::Error("invalid ACKS frame size ", sz, " < 12");
return false;
}
auto ptr = hdr.data();
uint64_t msgid;
uint32_t bitmask;
memcpy(&msgid, ptr, 8);
memcpy(&bitmask, ptr + 8, 4);
auto itr = tx.find(msgid);
if(itr == tx.end())
{
llarp::Error("ACK for missing TX frame msgid=", msgid);
return false;
}
transit_message *msg = itr->second;
msg->ack(bitmask);
if(msg->completed())
{
llarp::Debug("message transmitted msgid=", msgid);
session *impl = static_cast< session * >(parent->impl);
tx.erase(msgid);
delete msg;
}
else
{
llarp::Debug("message ", msgid, " retransmit fragments");
msg->retransmit_frags(sendqueue, txflags);
}
return true;
}
llarp_link *
session::get_parent(llarp_link_session *s)
{
session *link = static_cast< session * >(s->impl);
return link->serv->parent;
}
void
session::handle_verify_introack(iwp_async_introack *introack)
{
session *link = static_cast< session * >(introack->user);
link->working = false;
if(introack->buf == nullptr)
{
// invalid signature
llarp::Error("introack verify failed from ", link->addr);
// link->serv->RemoveSessionByAddr(link->addr);
return;
}
link->EnterState(eIntroAckRecv);
link->session_start();
}
void
session::handle_verify_session_start(iwp_async_session_start *s)
{
session *self = static_cast< session * >(s->user);
self->working = false;
if(!s->buf)
{
// verify fail
// TODO: remove session?
llarp::Warn("session start verify failed from ", self->addr);
return;
}
self->send_LIM();
}
server *
link_alloc(struct llarp_router *router, const char *keyfile,
struct llarp_crypto *crypto, struct llarp_logic *logic,
struct llarp_threadpool *worker)
{
server *link = new server(router, crypto, logic, worker);
llarp::Zero(link->keyfile, sizeof(link->keyfile));
strncpy(link->keyfile, keyfile, sizeof(link->keyfile));
return link;
}
const char *
link_name()
{
return "IWP";
}
void
link_get_addr(struct llarp_link *l, struct llarp_ai *addr)
{
server *link = static_cast< server * >(l->impl);
addr->rank = 1;
strncpy(addr->dialect, link_name(), sizeof(addr->dialect));
memcpy(addr->enc_key, link->pubkey(), 32);
memcpy(addr->ip.s6_addr, link->addr.addr6(), 16);
addr->port = link->addr.port();
}
const char *
outboundLink_name()
{
return "OWP";
}
bool
link_configure(struct llarp_link *l, struct llarp_ev_loop *netloop,
const char *ifname, int af, uint16_t port)
{
server *link = static_cast< server * >(l->impl);
if(!link->ensure_privkey())
{
llarp::Error("failed to ensure private key");
return false;
}
llarp::Debug("configure link ifname=", ifname, " af=", af, " port=", port);
// bind
sockaddr_in ip4addr;
sockaddr_in6 ip6addr;
sockaddr *addr = nullptr;
switch(af)
{
case AF_INET:
addr = (sockaddr *)&ip4addr;
llarp::Zero(addr, sizeof(ip4addr));
break;
case AF_INET6:
addr = (sockaddr *)&ip6addr;
llarp::Zero(addr, sizeof(ip6addr));
break;
// TODO: AF_PACKET
default:
llarp::Error(__FILE__, "unsupported address family", af);
return false;
}
addr->sa_family = af;
if(!llarp::StrEq(ifname, "*"))
{
if(!llarp_getifaddr(ifname, af, addr))
{
llarp::Error("failed to get address of network interface ", ifname);
return false;
}
}
else
l->name = outboundLink_name;
switch(af)
{
case AF_INET:
ip4addr.sin_port = htons(port);
break;
case AF_INET6:
ip6addr.sin6_port = htons(port);
break;
// TODO: AF_PACKET
default:
return false;
}
link->addr = *addr;
link->netloop = netloop;
link->udp.recvfrom = &server::handle_recvfrom;
link->udp.user = link;
llarp::Debug("bind IWP link to ", link->addr);
if(llarp_ev_add_udp(link->netloop, &link->udp, link->addr) == -1)
{
llarp::Error("failed to bind to ", link->addr);
return false;
}
return true;
}
bool
link_start(struct llarp_link *l, struct llarp_logic *logic)
{
server *link = static_cast< server * >(l->impl);
// give link implementations
link->parent = l;
link->timeout_job_id = 0;
link->logic = logic;
// start cleanup timer
link->issue_cleanup_timer(2500);
return true;
}
bool
link_stop(struct llarp_link *l)
{
server *link = static_cast< server * >(l->impl);
link->cancel_timer();
llarp_ev_close_udp(&link->udp);
link->clear_sessions();
return true;
}
void
link_iter_sessions(struct llarp_link *l, struct llarp_link_session_iter iter)
{
server *link = static_cast< server * >(l->impl);
auto sz = link->m_sessions.size();
if(sz)
{
llarp::Debug("we have ", sz, "sessions");
iter.link = l;
// TODO: race condition with cleanup timer
for(auto &item : link->m_sessions)
if(item.second.impl)
if(!iter.visit(&iter, &item.second))
return;
}
}
bool
link_try_establish(struct llarp_link *l, struct llarp_link_establish_job *job)
{
server *link = static_cast< server * >(l->impl);
{
llarp::Addr dst(job->ai);
llarp::Debug("establish session to ", dst);
session *s = link->find_session(dst);
if(s == nullptr)
{
s = link->create_session(dst);
link->put_session(dst, s);
}
s->establish_job = job;
s->frame.alive(); // mark it alive
s->introduce(job->ai.enc_key);
}
return true;
}
void
link_mark_session_active(struct llarp_link *link,
struct llarp_link_session *s)
{
static_cast< session * >(s->impl)->frame.alive();
}
void
link_free(struct llarp_link *l)
{
server *link = static_cast< server * >(l->impl);
delete link;
}
void
session::handle_establish_timeout(void *user, uint64_t orig, uint64_t left)
{
if(orig == 0)
return;
session *self = static_cast< session * >(user);
self->establish_job_id = 0;
if(self->establish_job)
{
auto job = self->establish_job;
self->establish_job = nullptr;
job->link = self->serv->parent;
if(self->IsEstablished())
{
job->session = self->parent;
}
else
{
// timer timeout
job->session = nullptr;
}
job->result(job);
}
}
void
session::handle_introack_generated(iwp_async_introack *i)
{
session *link = static_cast< session * >(i->user);
if(i->buf)
{
// track it with the server here
if(link->serv->has_session_to(link->addr))
{
// duplicate session
llarp::Warn("duplicate session to ", link->addr);
delete link;
return;
}
link->serv->put_session(link->addr, link);
llarp::Debug("send introack to ", link->addr, " via ", link->serv->addr);
if(llarp_ev_udp_sendto(link->udp, link->addr, i->buf, i->sz) == -1)
{
llarp::Warn("sendto failed");
return;
}
link->EnterState(eIntroAckSent);
}
else
{
// failed to generate?
llarp::Warn("failed to generate introack");
delete link;
}
}
} // namespace iwp
extern "C" {
void
iwp_link_init(struct llarp_link *link, struct llarp_iwp_args args)
{
link->impl = iwp::link_alloc(args.router, args.keyfile, args.crypto,
args.logic, args.cryptoworker);
link->name = iwp::link_name;
link->get_our_address = iwp::link_get_addr;
link->configure = iwp::link_configure;
link->start_link = iwp::link_start;
link->stop_link = iwp::link_stop;
link->iter_sessions = iwp::link_iter_sessions;
link->try_establish = iwp::link_try_establish;
link->has_session_to = iwp::server::HasSessionToRouter;
link->sendto = iwp::server::SendToSession;
link->mark_session_active = iwp::link_mark_session_active;
link->free_impl = iwp::link_free;
}
}