void free_peer_node(Peer *node)
{
if(node == NULL) return;
if(node->bitmap.bitfield != NULL) {
free(node->bitmap.bitfield);
node->bitmap.bitfield = NULL;
}
if(node->in_buff != NULL) {
free(node->in_buff);
node->in_buff = NULL;
}
if(node->out_msg != NULL) {
free(node->out_msg);
node->out_msg = NULL;
}
if(node->out_msg_copy != NULL) {
free(node->out_msg_copy);
node->out_msg_copy = NULL;
}
cancel_request_list(node);
cancel_requested_list(node);
// 释放完peer成员的内存后,再释放peer所占的内存
free(node);
}
// 找出当前下载速度最快的4个peer,将其unchoke
int select_unchoke_peer()
{
Peer* p;
Peer* now_fast[UNCHOKE_COUNT];
Peer* force_choke[UNCHOKE_COUNT];
int unchoke_socket[UNCHOKE_COUNT], choke_socket[UNCHOKE_COUNT];
int i, j, index = 0, len = UNCHOKE_COUNT;
int have_not_unchoke[UNCHOKE_COUNT];
//初始化变量
for(i = 0; i < len; i++) {
now_fast[i] = NULL;
force_choke[i] = NULL;
unchoke_socket[i] = -1;
choke_socket[i] = -1;
have_not_unchoke[i] = -1;
}
// 将那些在过去10秒已断(被剔出peer表）开连接而又处于unchoke队列中的peer清除出unchoke队列
for(i = 0, j = 0; i < unchoke_peers.count; i++) {
p = peer_head;
while(p != NULL) {
if(p == unchoke_peers.unchkpeer[i]) break;
p = p->next;
}
if(p == NULL) //不在peer链表中，说明已经断开
{ unchoke_peers.unchkpeer[i] = NULL; j++; }
}
if(j != 0) {
unchoke_peers.count = unchoke_peers.count - j;//剩下非阻塞数组未断开的个数
for(i = 0, j = 0; i < len; i++) {
if(unchoke_peers.unchkpeer[i] != NULL) {
force_choke[j] = unchoke_peers.unchkpeer[i];
j++;
}
}
for(i = 0; i < len; i++) {//有效的挪到数组前排
unchoke_peers.unchkpeer[i] = force_choke[i];
force_choke[i] = NULL;
}
}
// unchoke队列中，将那些在过去10秒上传速度超过20KB/S而下载速度过小的peer强行阻塞
// 注意：up_rate和down_rate的单位是B/S而不是KB/S
for(i = 0, j = -1; i < unchoke_peers.count; i++) {
if( (unchoke_peers.unchkpeer)[i]->up_rate > 50*1024 && //到底是50k还是20k？
(unchoke_peers.unchkpeer)[i]->down_rate < 0.1*1024 ) {
j++;
force_choke[j] = unchoke_peers.unchkpeer[i];
}
}
// 从当前所有Peer中选出下载速度最快的四个peer，存于now_fast中
p = peer_head;
while(p != NULL) {
if(p->state==DATA && is_interested(bitmap,&(p->bitmap)) && is_seed(p)!=1) {//state?交换数据？
// p不应该在force_choke数组中
for(i = 0; i < len; i++) {
if(p == force_choke[i])
break;
}
if(i == len) {
if( index < UNCHOKE_COUNT ) {
now_fast[index] = p;
index++;
} else { //数组满了
j = get_last_index(now_fast,UNCHOKE_COUNT); //找now_fast最慢的那个和这个比较
if(p->down_rate >= now_fast[j]->down_rate) now_fast[j] = p;
}
}
}
p = p->next;
}
/**************************以下一段需要改进**********************************/
/*
// 假设now_fast中所有的peer都是要unchoke的，取出各自的socket
for(i = 0; i < index; i++) {
Peer* q = now_fast[i];
unchoke_socket[i] = q->socket;
}
// 假设unchoke_peers.unchkpeer中所有peer都是choke的，取出各自的socket
for(i = 0; i < unchoke_peers.count; i++) {
Peer* q = (unchoke_peers.unchkpeer)[i];
choke_socket[i] = q->socket;
}
// 如果now_fast某个元素已经存在于unchoke_peers.unchkpeer
// 则没有必要进行choke或unckoke
for(i = 0; i < index; i++) {
if( is_in_unchoke_peers(now_fast[i]) == 1) {//在unchoke_peers.unchkpeer，不用阻塞
// for(j = 0; j < len; j++) { //index与len不一定对应=4//但循环是为什么
Peer* q = now_fast[i];
if(q->socket == unchoke_socket[i]) unchoke_socket[i] = -1;
if(q->socket == choke_socket[i]) choke_socket[i] = -1;
// }
}
}
// 更新当前unchoke的peer
for(i = 0; i < index; i++) {
(unchoke_peers.unchkpeer)[i] = now_fast[i];
}
unchoke_peers.count = index;
// 状态变化后,要对peer的状态值重新赋值,并且创建choke、unchoke消息
p = peer_head;
while(p != NULL) {
for(i = 0; i < len; i++) {
if(unchoke_socket[i]==p->socket && unchoke_socket[i]!=-1) {
p->am_choking = 0;//非阻塞
create_chock_interested_msg(1,p);
}
if(choke_socket[i]==p->socket && unchoke_socket[i]!=-1) {
p->am_choking = 1;
cancel_requested_list(p);
create_chock_interested_msg(0,p);
}
}
p = p->next;
}
*/
/*******************************改进后*************************/
for (i = 0; i < unchoke_peers.count; i++) {
p = (unchoke_peers.unchkpeer)[i];
for (j = 0; j < index; j++) {
if(p == now_fast[j]) {
break;
}
}
if(j == index) {//peer在非阻塞队列中，但不在刚选出的now_fast中，将它阻塞
p->am_choking = 1;
cancel_requested_list(p);
create_chock_interested_msg(0,p);
}
else {
have_not_unchoke[j] = 1;//记下now_fast中不必unchoke的位置
}
}
for(i = 0; i < index; i++) {
if(have_not_unchoke[i] != 1) { //说明now_fast对应位置要unchoke
now_fast[i]->am_choking = 0;//转入非阻塞状态
create_chock_interested_msg(1,now_fast[i]);
}
}
//更新unchoke_peers
for(i = 0; i < index; i++) {
(unchoke_peers.unchkpeer)[i] = now_fast[i];
}
unchoke_peers.count = index;
/*****************************改进结束**************************/
for(i = 0; i < unchoke_peers.count; i++)
printf("unchoke peer:%s \n",(unchoke_peers.unchkpeer)[i]->ip);
printf("***********************************************\n");
return 0;
}