char *new_packet(int proto, int option, int *size)
{
char *packet = NULL;
int packet_size = 0;
char padding_offset = 0;
int padding_len = 0;
switch (proto) {
case IPPROTO_TCP:
packet_size = sizeof(struct iphdr) + sizeof(struct tcphdr);
break;
case IPPROTO_UDP:
packet_size = sizeof(struct iphdr) + sizeof(struct udphdr);
break;
case IPPROTO_ICMP:
packet_size = sizeof(struct iphdr) + sizeof(struct icmphdr);
break;
default:
warn("this protocal is unsupported");
*size = 0;
return NULL;
}
if (option & PACK_PADDING) {
padding_len = get_rand_int(MAX_PADDING_LEN);
padding_len = padding_len - padding_len % (sizeof(int));
padding_offset = packet_size;
packet_size += padding_len;
}
packet = safe_malloc(packet_size);
if (option & PACK_PADDING) {
fill_buf_rand(packet + padding_offset, padding_len);
}
*size = packet_size;
return packet;
}
int find_min_cut(int **adj_list, int *lengths, int adj_list_len)
{
int nodes_num = adj_list_len;
while(nodes_num > 2)
{
int node_1, node_2;
do
{
node_1 = get_rand_int(adj_list_len);
}
while(lengths[node_1] == 0);
node_2 = adj_list[node_1][ get_rand_int(lengths[node_1]) ];
merge_nodes(adj_list, lengths, adj_list_len, node_1, node_2);
--nodes_num;
}
/* find cut */
int i;
for(i = 0; lengths[i] == 0; ++i)
;
return lengths[i];
}
/*get non-negative integer values with a given sum*/
std::vector<double> get_rand_int_with_sum(int num, int sum)
{
std::vector<double> result(num,0);
int t_sum = sum;
for(int i = 0; i < num; i++){
int value = get_rand_int(0, t_sum);
t_sum -= value;
if(t_sum >= 0)
result[i] = value;
else
break;
}
return result;
}
