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ames: add stun client for informal pings #509

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ames: add stun client for informal pings #509

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b608007
stun: WIP but compiles
belisarius222 Sep 1, 2023
ad238b5
stun: use later RFC for packet format
belisarius222 Sep 19, 2023
6ad7a1d
Merge branch 'develop' into ted/ping
pkova Oct 20, 2023
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1 change: 1 addition & 0 deletions pkg/c3/motes.h
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Original file line number Diff line number Diff line change
Expand Up @@ -998,6 +998,7 @@
# define c3__sard c3_s4('s','a','r','d')
# define c3__sav c3_s3('s','a','v')
# define c3__save c3_s4('s','a','v','e')
# define c3__saxo c3_s4('s','a','x','o')
# define c3__scam c3_s4('s','c','a','m')
# define c3__scan c3_s4('s','c','a','n')
# define c3__scry c3_s4('s','c','r','y')
Expand Down
227 changes: 223 additions & 4 deletions pkg/vere/io/ames.c
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Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,12 @@

#define QUEUE_MAX 30 // max number of packets in queue

typedef enum u3_stun_state {
STUN_OFF = 0,
STUN_TRYING = 1,
STUN_KEEPALIVE = 2,
} u3_stun_state;

/* u3_fine: fine networking
*/
typedef struct _u3_fine {
Expand Down Expand Up @@ -45,6 +51,16 @@
c3_w imp_w[256]; // imperial IPs
time_t imp_t[256]; // imperial IP timestamps
c3_o imp_o[256]; // imperial print status
struct { // stun client state:
u3_stun_state sat_y; // formal state
c3_y tid_y[16]; // last transaction id
c3_d dad_d[2]; // sponsoring ship @p
u3_lane lan_u; // sponsoring ship IP and port
uv_timer_t tim_u; // keepalive timer handle
struct timeval las_u; // last sent date
struct timeval sar_u; // date we started trying to send
u3_lane sef_u; // our lane, if we know it
} sun_u; //
struct { // config:
c3_o net_o; // can send
c3_o see_o; // can scry
Expand Down Expand Up @@ -1170,6 +1186,205 @@ _fine_put_cache(u3_ames* sam_u, u3_noun pax, c3_w lop_w, u3_noun lis)
}
}

static void
_stun_stop(u3_ames* sam_u)
{
switch ( sam_u->sun_u.sat_y ) {
case STUN_OFF: break; // ignore; already stopped
case STUN_TRYING: {
uv_timer_stop(&sam_u->sun_u.tim_u);
} break;
case STUN_KEEPALIVE: {
uv_timer_stop(&sam_u->sun_u.tim_u);
} break;
default: u3_assert(!"programmer error");
}
sam_u->sun_u.sat_y = STUN_OFF;
}

static void _stun_send_request(u3_ames*); // forward declaration

static void
_stun_timer_cb(uv_timer_t* tim_u)
{
u3_ames* sam_u = (u3_ames*)(tim_u->data);
switch ( sam_u->sun_u.sat_y ) {
case STUN_OFF: {
// ignore; stray timer (although this shouldn't happen)
u3l_log("stun: stray timer STUN_OFF");
} break;
case STUN_KEEPALIVE: {
sam_u->sun_u.sat_y = STUN_TRYING;
_stun_send_request(sam_u);
} break;
case STUN_TRYING: {
c3_d gap_d;
{
struct timeval tim_tv;
gettimeofday(&tim_tv, 0);
u3_noun now = u3_time_in_tv(&tim_tv);
u3_noun den = u3_time_in_tv(&sam_u->sun_u.sar_u);
gap_d = u3_time_gap_ms(den, now);
}
if ( gap_d >= (5 * 1000) ) {
_stun_stop(sam_u);
// TODO inject event into arvo to ping repeatedly
}
else {
sam_u->sun_u.tim_u.data = sam_u;
uv_timer_start(&sam_u->sun_u.tim_u, _stun_timer_cb, 1*1000, 0);
}
} break;
default: u3_assert(!"programmer error");
}
}

typedef struct _u3_stun_send {
uv_udp_send_t req_u; // uv udp request handle
u3_ames* sam_u; // backpointer to driver state
} u3_stun_send;

static void
_stun_send_cb(uv_udp_send_t *req_u, c3_i sas_i)
{
u3_stun_send* snd_u = (u3_stun_send*)req_u;
if ( sas_i ) {
// TODO take error handling action
}
else {
u3_ames* sam_u = snd_u->sam_u;
gettimeofday(&sam_u->sun_u.las_u, 0); // overwrite last sent date
}
}

static void
_stun_on_response(u3_ames* sam_u) // TODO read arg
{
u3_stun_state old_y = sam_u->sun_u.sat_y;
switch ( sam_u->sun_u.sat_y ) {
case STUN_OFF: break; // ignore; stray response
case STUN_KEEPALIVE: break; // ignore; duplicate response
case STUN_TRYING: {
sam_u->sun_u.sat_y = STUN_KEEPALIVE;
sam_u->sun_u.tid_y[1]++;
uv_timer_stop(&sam_u->sun_u.tim_u);
sam_u->sun_u.tim_u.data = sam_u;
uv_timer_start(&sam_u->sun_u.tim_u, _stun_timer_cb, 25*1000, 0);
} break;
default: assert("programmer error");
}
}
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This should either be called from _ames_recv_cb() (if we can always distinguish STUN responses preemptively), or from _ames_hear() (as a fallback if a packet is not a valid ames packet).

I believe the response will look like:

c3_y rep_y[20] = {
  0x1, 0x1,                // binding resp
  0x??, 0x??,              // len (including optional attributes)
  0x21, 0x12, 0xA4, 0x42,  // cookie
  ... original 12 bytes of randomness
  ... XOR-mapped address attribute
}

An ames header will never begin with { 0x1, 0x1 } (binding success response) or { 0x1, 0x11 } (binding error response), so that plus a sanity check of the constant "STUN cookie" should be enough to distinguish protocols.

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I'm going off the rfc (https://www.rfc-editor.org/rfc/rfc8489), and sanity checking that with packet captures (https://www.cloudshark.org/captures/4686b8430477).


static void
_stun_send_request(u3_ames* sam_u)
{
u3_assert( STUN_OFF != sam_u->sun_u.sat_y );

struct sockaddr_in add_u;
memset(&add_u, 0, sizeof(add_u));
add_u.sin_family = AF_INET;
add_u.sin_addr.s_addr = htonl(sam_u->sun_u.lan_u.pip_w);
add_u.sin_port = htons(sam_u->sun_u.lan_u.por_s);

// see STUN RFC 8489
// https://datatracker.ietf.org/doc/html/rfc8489#section-5
c3_y buf_y[20] = {0};

// STUN message type: "binding request"
buf_y[1] = 0x01;

// STUN message length: 0 (header-only)
// (implicit in initialization)

// STUN "magic cookie" 0x2112A442 in network byte order
buf_y[4] = 0x21; buf_y[5] = 0x12; buf_y[6] = 0xa4; buf_y[7] = 0x42;

// STUN "transaction id"
memcpy(buf_y + 8, sam_u->sun_u.tid_y, 12);

uv_buf_t buf_u = uv_buf_init((c3_c*)buf_y, 20);
u3_stun_send* snd_u = c3_calloc(sizeof(*snd_u));
snd_u->sam_u = sam_u;
c3_i sas_i = uv_udp_send(
(uv_udp_send_t*)snd_u, &sam_u->wax_u, &buf_u, 1,
(const struct sockaddr*)&add_u, _stun_send_cb
);

if ( sas_i ) {
u3l_log("stun: send fail_sync: %s", uv_strerror(sas_i));
// TODO take error handling actions
}
}

static void
_stun_czar_cb(uv_getaddrinfo_t* adr_u,
c3_i sas_i,
struct addrinfo* aif_u)
{
u3_ames* sam_u; // TODO get sam_u from args
gettimeofday(&sam_u->sun_u.sar_u, 0); // set start time to now
_stun_send_request(sam_u);
uv_timer_start(&sam_u->sun_u.tim_u, _stun_timer_cb, 1, 0);

}

static void
_stun_czar(u3_ames* sam_u)
{
// TODO rip off _ames_czar()
}

static void
_stun_start(u3_ames* sam_u, u3_noun dad)
{
sam_u->sun_u.sat_y = STUN_TRYING;
u3r_chubs(0, 2, sam_u->sun_u.dad_d, dad);
u3z(dad);

// initialize STUN transaction id to mug of now
{
u3_noun mug;
struct timeval tim_u;
gettimeofday(&tim_u, 0);

mug = u3r_mug(u3_time_in_tv(&tim_u));
memcpy(sam_u->sun_u.tid_y, (c3_y*)&mug, 4);
u3z(mug);
}

_stun_czar(sam_u);
}

static c3_o
_ames_is_czar(u3_noun who)
{
u3_noun rac = u3do("clan:title", u3k(who));
c3_o zar = ( c3y == (c3__czar == rac) );
u3z(rac);
return zar;
}

/* _ames_ef_saxo(): handle sponsorship chain notification
*/
static void
_ames_ef_saxo(u3_ames* sam_u, u3_noun zad)
{
u3_noun daz, dad;

daz = u3qb_flop(zad);
if ( u3_nul == daz ) {
u3l_log("ames: empty sponsorship chain");
return;
}

dad = u3k(u3h(daz));
if ( c3y == _ames_is_czar(dad) ) {
_stun_stop(sam_u);
_stun_start(sam_u, u3k(dad));
}

u3z(zad); u3z(daz); u3z(dad);
}

/* _ames_ef_send(): send packet to network (v4).
*/
Expand Down Expand Up @@ -2063,10 +2278,11 @@ _ames_io_start(u3_ames* sam_u)
{
c3_s por_s = sam_u->pir_u->por_s;
u3_noun who = u3i_chubs(2, sam_u->pir_u->who_d);
u3_noun rac = u3do("clan:title", u3k(who));
c3_o zar_o = _ames_is_czar(who);
c3_i ret_i;

if ( c3__czar == rac ) {

if ( c3y == zar_o ) {
c3_y num_y = (c3_y)sam_u->pir_u->who_d[0];
c3_s zar_s = _ames_czar_port(num_y);

Expand Down Expand Up @@ -2096,7 +2312,7 @@ _ames_io_start(u3_ames* sam_u)
{
u3l_log("ames: bind: %s", uv_strerror(ret_i));

if ( (c3__czar == rac) &&
if ( (c3y == zar_o) &&
(UV_EADDRINUSE == ret_i) )
{
u3l_log(" ...perhaps you've got two copies of vere running?");
Expand All @@ -2123,7 +2339,6 @@ _ames_io_start(u3_ames* sam_u)
uv_udp_recv_start(&sam_u->wax_u, _ames_alloc, _ames_recv_cb);

sam_u->car_u.liv_o = c3y;
u3z(rac);
u3z(who);
}

Expand Down Expand Up @@ -2272,6 +2487,10 @@ _ames_kick_newt(u3_ames* sam_u, u3_noun tag, u3_noun dat)
_ames_ef_turf(sam_u, u3k(dat));
ret_o = c3y;
} break;

case c3__saxo: {
_ames_ef_saxo(sam_u, u3k(dat));
} break;
}

u3z(tag); u3z(dat);
Expand Down