static void
hostfrag_create(struct ip * iph)
{
// mknew函数最终调用了malloc以字节为单位分配内存
struct hostfrags *hf = mknew(struct hostfrags);
// 生成hash index
int hash_index = frag_index(iph);
// 填充hostfrags 结构体
hf->prev = 0;
// 插入到hash表头
hf->next = fragtable[hash_index];
// 维护双向链表
if (hf->next)
hf->next->prev = hf;
// 挂到hash表上
fragtable[hash_index] = hf;
// 填充ip
hf->ip = iph->ip_dst.s_addr;
// 数据报队列初始化为空
hf->ipqueue = 0;
// 占用内存大小初始化为0
hf->ip_frag_mem = 0;
hf->hash_index = hash_index;
// 设置当前host为刚刚创建的host
this_host = hf;
}
static void
hostfrag_create(struct ip * iph)
{
struct hostfrags *hf = mknew(struct hostfrags);
int hash_index = frag_index(iph);
hf->prev = 0;
hf->next = fragtable[hash_index];
if (hf->next)
hf->next->prev = hf;
fragtable[hash_index] = hf;
hf->ip = iph->ip_dst.s_addr;
hf->ipqueue = 0;
hf->ip_frag_mem = 0;
hf->hash_index = hash_index;
this_host = hf;
}
static int
hostfrag_find(struct ip * iph)
{
int hash_index = frag_index(iph);
struct hostfrags *hf;
this_host = 0;
for (hf = fragtable[hash_index]; hf; hf = hf->next)
if (hf->ip == iph->ip_dst.s_addr) {
this_host = hf;
break;
}
if (!this_host)
return 0;
else
return 1;
}
static void
//! hostfrag_create(struct ip * iph)
hostfrag_create(struct ip * iph,IP_THREAD_LOCAL_P ip_thread_local_p)
{
struct hostfrags *hf = mknew(struct hostfrags);
//! int hash_index = frag_index(iph);
int hash_index = frag_index(iph,ip_thread_local_p);
hf->prev = 0;
//! hf->next = fragtable[hash_index];
hf->next = ip_thread_local_p->fragtable[hash_index];
if (hf->next)
hf->next->prev = hf;
//! fragtable[hash_index] = hf;
ip_thread_local_p->fragtable[hash_index] = hf;
hf->ip = iph->ip_dst.s_addr;
hf->ipqueue = 0;
hf->ip_frag_mem = 0;
hf->hash_index = hash_index;
//! this_host = hf;
ip_thread_local_p->this_host = hf;
}
// 根据所给的ip头，找到与这个ip碎片对应的主机相关信息
// 这个主机相关信息，由全局变量this_host保存
// 成功更新this_host，返回1，否则返回0， this_host也为0
//
// 从这个函数可以看出，每一个host被放在一个hash项中，
// 采用的是链表法解决hash冲突
static int
hostfrag_find(struct ip * iph)
{
// 首先生成一个hash index
int hash_index = frag_index(iph);
struct hostfrags *hf;
// 将全局变量清零,这个全局变量总是指向当前报文对应的host
this_host = 0;
//
for (hf = fragtable[hash_index]; hf; hf = hf->next)
if (hf->ip == iph->ip_dst.s_addr)
{
this_host = hf;
break;
}
// 如果找不到，则返回0，否则返回1
if (!this_host)
return 0;
else
return 1;
}
static int
//! hostfrag_find(struct ip * iph)
hostfrag_find(struct ip * iph,IP_THREAD_LOCAL_P ip_thread_local_p)
{
//! int hash_index = frag_index(iph);
int hash_index = frag_index(iph,ip_thread_local_p);
struct hostfrags *hf;
//! this_host = 0;
ip_thread_local_p->this_host = NULL;
//! for (hf = fragtable[hash_index]; hf; hf = hf->next)
for (hf = ip_thread_local_p->fragtable[hash_index]; hf; hf = hf->next)
if (hf->ip == iph->ip_dst.s_addr) {
//! this_host = hf;
ip_thread_local_p->this_host = hf;
break;
}
//! if (!this_host)
if (!ip_thread_local_p->this_host)
return 0;
else
return 1;
}
