int
generate_pkt (
struct pkt *x_pkt,
const struct timeval *tv_xmt,
int key_id,
struct key *pkt_key
)
{
l_fp xmt;
int pkt_len = LEN_PKT_NOMAC;
memset(x_pkt, 0, sizeof(struct pkt));
TVTOTS(tv_xmt, &xmt);
HTONL_FP(&xmt, &(x_pkt->xmt));
x_pkt->stratum = STRATUM_TO_PKT(STRATUM_UNSPEC);
x_pkt->ppoll = 8;
/* FIXME! Modus broadcast + adr. check -> bdr. pkt */
set_li_vn_mode(x_pkt, LEAP_NOTINSYNC, 4, 3);
if (pkt_key != NULL) {
int mac_size = 20; /* max room for MAC */
x_pkt->exten[0] = htonl(key_id);
mac_size = make_mac((char *)x_pkt, pkt_len, mac_size, pkt_key, (char *)&x_pkt->exten[1]);
if (mac_size)
pkt_len += mac_size + 4;
}
return pkt_len;
}
int
generate_pkt (
struct pkt *x_pkt,
const struct timeval *tv_xmt,
int key_id,
struct key *pkt_key
)
{
l_fp xmt_fp;
int pkt_len;
int mac_size;
pkt_len = LEN_PKT_NOMAC;
ZERO(*x_pkt);
TVTOTS(tv_xmt, &xmt_fp);
HTONL_FP(&xmt_fp, &x_pkt->xmt);
x_pkt->stratum = STRATUM_TO_PKT(STRATUM_UNSPEC);
x_pkt->ppoll = 8;
/* FIXME! Modus broadcast + adr. check -> bdr. pkt */
set_li_vn_mode(x_pkt, LEAP_NOTINSYNC, ntpver, 3);
if (debug > 0) {
printf("generate_pkt: key_id %d, key pointer %p\n", key_id, pkt_key);
}
if (pkt_key != NULL) {
x_pkt->exten[0] = htonl(key_id);
mac_size = make_mac(x_pkt, pkt_len, MAX_MDG_LEN,
pkt_key, (char *)&x_pkt->exten[1]);
if (mac_size > 0)
pkt_len += mac_size + KEY_MAC_LEN;
#ifdef DEBUG
if (debug > 0) {
printf("generate_pkt: mac_size is %d\n", mac_size);
}
#endif
}
return pkt_len;
}
/* Define a function to simulate a server.
* This function processes the sent packet according to the server script,
* creates a reply packet and pushes the reply packet onto the event queue
*/
int simulate_server(
sockaddr_u *serv_addr, /* Address of the server */
struct interface *inter, /* Interface on which the reply should
be inserted */
struct pkt *rpkt /* Packet sent to the server that
needs to be processed. */
)
{
struct pkt xpkt; /* Packet to be transmitted back
to the client */
struct recvbuf rbuf; /* Buffer for the received packet */
Event *e; /* Packet receive event */
server_info *server; /* Pointer to the server being simulated */
script_info *curr_script; /* Current script being processed */
int i;
double d1, d2, d3; /* Delays while the packet is enroute */
double t1, t2, t3, t4; /* The four timestamps in the packet */
memset(&xpkt, 0, sizeof(xpkt));
memset(&rbuf, 0, sizeof(rbuf));
/* Search for the server with the desired address */
server = NULL;
for (i = 0; i < simulation.num_of_servers; ++i) {
fprintf(stderr,"Checking address: %s\n", stoa(simulation.servers[i].addr));
if (memcmp(simulation.servers[i].addr, serv_addr,
sizeof(*serv_addr)) == 0) {
server = &simulation.servers[i];
break;
}
}
fprintf(stderr, "Received packet for: %s\n", stoa(serv_addr));
if (server == NULL)
abortsim("Server with specified address not found!!!");
/* Get the current script for the server */
curr_script = server->curr_script;
/* Create a server reply packet.
* Masquerade the reply as a stratum-1 server with a GPS clock
*/
xpkt.li_vn_mode = PKT_LI_VN_MODE(LEAP_NOWARNING, NTP_VERSION,
MODE_SERVER);
xpkt.stratum = STRATUM_TO_PKT(((u_char)1));
memcpy(&xpkt.refid, "GPS", 4);
xpkt.ppoll = rpkt->ppoll;
xpkt.precision = rpkt->precision;
xpkt.rootdelay = 0;
xpkt.rootdisp = 0;
/* TIMESTAMP CALCULATIONS
t1 t4
\ /
d1 \ / d3
\ /
t2 ----------------- t3
d2
*/
/* Compute the delays */
d1 = poisson(curr_script->prop_delay, curr_script->jitter);
d2 = poisson(curr_script->proc_delay, 0);
d3 = poisson(curr_script->prop_delay, curr_script->jitter);
/* Note: In the transmitted packet:
* 1. t1 and t4 are times in the client according to the local clock.
* 2. t2 and t3 are server times according to the simulated server.
* Compute t1, t2, t3 and t4
* Note: This function is called at time t1.
*/
LFPTOD(&rpkt->xmt, t1);
t2 = server->server_time + d1;
t3 = server->server_time + d1 + d2;
t4 = t1 + d1 + d2 + d3;
/* Save the timestamps */
xpkt.org = rpkt->xmt;
DTOLFP(t2, &xpkt.rec);
DTOLFP(t3, &xpkt.xmt);
xpkt.reftime = xpkt.xmt;
/* Ok, we are done with the packet. Now initialize the receive buffer for
* the packet.
*/
rbuf.receiver = receive; /* Function to call to process the packet */
rbuf.recv_length = LEN_PKT_NOMAC;
rbuf.recv_pkt = xpkt;
rbuf.used = 1;
memcpy(&rbuf.srcadr, serv_addr, sizeof(rbuf.srcadr));
memcpy(&rbuf.recv_srcadr, serv_addr, sizeof(rbuf.recv_srcadr));
if ((rbuf.dstadr = malloc(sizeof(*rbuf.dstadr))) == NULL)
abortsim("malloc failed in simulate_server");
memcpy(rbuf.dstadr, inter, sizeof(*rbuf.dstadr));
/* rbuf.link = NULL; */
/* Create a packet event and insert it onto the event_queue at the
* arrival time (t4) of the packet at the client
*/
e = event(t4, PACKET);
e->rcv_buf = rbuf;
enqueue(event_queue, e);
/* Check if the time of the script has expired. If yes, delete the script.
* If not, re-enqueue the script onto the server script queue
*/
if (curr_script->duration > simulation.sim_time &&
!empty(server->script)) {
printf("Hello\n");
/*
* For some reason freeing up the curr_script memory kills the
* simulation. Further debugging is needed to determine why.
* free_node(curr_script);
*/
curr_script = dequeue(server->script);
}
return (0);
}
