cycle_t make_cycle(const cyclic_group_t* group, aesrand_t *aes)
{
cycle_t cycle;
cycle.group = group;
cycle.generator = find_primroot(group, aes);
cycle.offset = (uint32_t) (aesrand_getword(aes) & 0xFFFFFFFF);
cycle.offset %= group->prime;
return cycle;
}
// Return a (random) number coprime with (p - 1) of the group,
// which is a generator of the additive group mod (p - 1)
static uint32_t find_primroot(const cyclic_group_t *group)
{
uint32_t candidate = (uint32_t) ((aesrand_getword() & 0xFFFFFFFF) % group->prime);
while (check_coprime(candidate, group) != COPRIME) {
++candidate;
}
uint64_t retv = isomorphism(candidate, group);
return retv;
}
// Return a (random) number coprime with (p - 1) of the group,
// which is a generator of the additive group mod (p - 1)
static uint32_t find_primroot(const cyclic_group_t *group, aesrand_t *aes)
{
uint32_t candidate = (uint32_t) ((aesrand_getword(aes) & 0xFFFFFFFF) % group->prime);
if (candidate == 0) {
++candidate;
}
while (check_coprime(candidate, group) != COPRIME) {
++candidate;
//special case where we need to restart check from begin
if(candidate >= group->prime) {
candidate = 1;
}
}
uint64_t retv = isomorphism(candidate, group);
return retv;
}
// global sender initialize (not thread specific)
iterator_t* send_init(void)
{
// generate a new primitive root and starting position
iterator_t *it;
it = iterator_init(zconf.senders, zconf.shard_num, zconf.total_shards);
// process the dotted-notation addresses passed to ZMAP and determine
// the source addresses from which we'll send packets;
srcip_first = inet_addr(zconf.source_ip_first);
if (srcip_first == INADDR_NONE) {
log_fatal("send", "invalid begin source ip address: `%s'",
zconf.source_ip_first);
}
srcip_last = inet_addr(zconf.source_ip_last);
if (srcip_last == INADDR_NONE) {
log_fatal("send", "invalid end source ip address: `%s'",
zconf.source_ip_last);
}
log_debug("send", "srcip_first: %u", srcip_first);
log_debug("send", "srcip_last: %u", srcip_last);
if (srcip_first == srcip_last) {
srcip_offset = 0;
num_src_addrs = 1;
} else {
uint32_t ip_first = ntohl(srcip_first);
uint32_t ip_last = ntohl(srcip_last);
assert(ip_first && ip_last);
assert(ip_last > ip_first);
uint32_t offset = (uint32_t) (aesrand_getword(zconf.aes) & 0xFFFFFFFF);
srcip_offset = offset % (srcip_last - srcip_first);
num_src_addrs = ip_last - ip_first + 1;
}
// process the source port range that ZMap is allowed to use
num_src_ports = zconf.source_port_last - zconf.source_port_first + 1;
log_debug("send", "will send from %i address%s on %u source ports",
num_src_addrs, ((num_src_addrs ==1 ) ? "":"es"),
num_src_ports);
// global initialization for send module
assert(zconf.probe_module);
if (zconf.probe_module->global_initialize) {
zconf.probe_module->global_initialize(&zconf);
}
// concert specified bandwidth to packet rate
if (zconf.bandwidth > 0) {
int pkt_len = zconf.probe_module->packet_length;
pkt_len *= 8;
pkt_len += 8*24; // 7 byte MAC preamble, 1 byte Start frame,
// 4 byte CRC, 12 byte inter-frame gap
if (pkt_len < 84*8) {
pkt_len = 84*8;
}
if (zconf.bandwidth / pkt_len > 0xFFFFFFFF) {
zconf.rate = 0;
} else {
zconf.rate = zconf.bandwidth / pkt_len;
if (zconf.rate == 0) {
log_warn("send", "bandwidth %lu bit/s is slower than 1 pkt/s, "
"setting rate to 1 pkt/s", zconf.bandwidth);
zconf.rate = 1;
}
}
log_debug("send", "using bandwidth %lu bits/s, rate set to %d pkt/s",
zconf.bandwidth, zconf.rate);
}
// Get the source hardware address, and give it to the probe
// module
if (!zconf.hw_mac_set) {
if (get_iface_hw_addr(zconf.iface, zconf.hw_mac)) {
log_fatal("send", "could not retrieve hardware address for "
"interface: %s", zconf.iface);
return NULL;
}
log_debug("send", "no source MAC provided. "
"automatically detected %02x:%02x:%02x:%02x:%02x:%02x as hw "
"interface for %s",
zconf.hw_mac[0], zconf.hw_mac[1], zconf.hw_mac[2],
zconf.hw_mac[3], zconf.hw_mac[4], zconf.hw_mac[5],
zconf.iface);
}
log_debug("send", "source MAC address %02x:%02x:%02x:%02x:%02x:%02x",
zconf.hw_mac[0], zconf.hw_mac[1], zconf.hw_mac[2],
zconf.hw_mac[3], zconf.hw_mac[4], zconf.hw_mac[5]);
if (zconf.dryrun) {
log_info("send", "dryrun mode -- won't actually send packets");
}
// initialize random validation key
validate_init();
zsend.start = now();
return it;
}
