int raw_local_deliver(struct sk_buff *skb, int protocol)
{
int hash;
struct sock *raw_sk;
hash = protocol & (RAW_HTABLE_SIZE - 1);
raw_sk = sk_head(&raw_v4_hashinfo.ht[hash]);
/* If there maybe a raw socket we must check - if not we
* don't care less
*/
if (raw_sk && !raw_v4_input(skb, ip_hdr(skb), hash))
raw_sk = NULL;
return raw_sk != NULL;
}
int raw_local_deliver(struct sk_buff *skb, int protocol)
{
int hash;
struct sock *raw_sk;
//根据protocol来得到raw_v4_hashinfo上的一个hash数组项..(bucket).这个bucket存放的都是该protocl的struct sock...
//可以认为是一个链表的head咯...
//这个链表的结点是包含在struct sock结构体的...
hash = protocol & (RAW_HTABLE_SIZE - 1);
raw_sk = sk_head(&raw_v4_hashinfo.ht[hash]);
/* If there maybe a raw socket we must check - if not we
* don't care less
*/
//raw_v4_input的返回值为是否有程序处理该数据包....如果返回为0就是没有查找到..返回1代表有查找到..
//然后在看返回值..可见如果返回为1那就是有raw的socket处理了..否则没有啦.
if (raw_sk && !raw_v4_input(skb, ip_hdr(skb), hash))
raw_sk = NULL;
return raw_sk != NULL;
}
static inline int ip_local_deliver_finish(struct sk_buff *skb)
{
int ihl = skb->nh.iph->ihl*4;
#ifdef CONFIG_NETFILTER_DEBUG
nf_debug_ip_local_deliver(skb);
#endif /*CONFIG_NETFILTER_DEBUG*/
__skb_pull(skb, ihl);
#ifdef CONFIG_NETFILTER
/* Free reference early: we don't need it any more, and it may
hold ip_conntrack module loaded indefinitely. */
nf_conntrack_put(skb->nfct);
skb->nfct = NULL;
#endif /*CONFIG_NETFILTER*/
/* Point into the IP datagram, just past the header. */
skb->h.raw = skb->data;
{
/* Note: See raw.c and net/raw.h, RAWV4_HTABLE_SIZE==MAX_INET_PROTOS */
int protocol = skb->nh.iph->protocol;
int hash = protocol & (MAX_INET_PROTOS - 1);
struct sock *raw_sk = raw_v4_htable[hash];
struct inet_protocol *ipprot;
int flag;
/* If there maybe a raw socket we must check - if not we
* don't care less
*/
if(raw_sk != NULL)
raw_sk = raw_v4_input(skb, skb->nh.iph, hash);
ipprot = (struct inet_protocol *) inet_protos[hash];
flag = 0;
if(ipprot != NULL) {
if(raw_sk == NULL &&
ipprot->next == NULL &&
ipprot->protocol == protocol) {
int ret;
/* Fast path... */
ret = ipprot->handler(skb);
return ret;
} else {
flag = ip_run_ipprot(skb, skb->nh.iph, ipprot, (raw_sk != NULL));
}
}
/* All protocols checked.
* If this packet was a broadcast, we may *not* reply to it, since that
* causes (proven, grin) ARP storms and a leakage of memory (i.e. all
* ICMP reply messages get queued up for transmission...)
*/
if(raw_sk != NULL) { /* Shift to last raw user */
raw_rcv(raw_sk, skb);
sock_put(raw_sk);
} else if (!flag) { /* Free and report errors */
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PROT_UNREACH, 0);
kfree_skb(skb);
}
}
return 0;
}
static inline int ip_local_deliver_finish(struct sk_buff *skb)
{
int ihl = skb->nh.iph->ihl*4;
#ifdef CONFIG_NETFILTER_DEBUG
nf_debug_ip_local_deliver(skb);
#endif /*CONFIG_NETFILTER_DEBUG*/
__skb_pull(skb, ihl);
/* Free reference early: we don't need it any more, and it may
hold ip_conntrack module loaded indefinitely. */
nf_reset(skb);
/* Point into the IP datagram, just past the header. */
skb->h.raw = skb->data;
rcu_read_lock();
{
/* Note: See raw.c and net/raw.h, RAWV4_HTABLE_SIZE==MAX_INET_PROTOS */
int protocol = skb->nh.iph->protocol;
int hash;
struct sock *raw_sk;
struct net_protocol *ipprot;
resubmit:
hash = protocol & (MAX_INET_PROTOS - 1);
raw_sk = sk_head(&raw_v4_htable[hash]);
/* If there maybe a raw socket we must check - if not we
* don't care less
*/
if (raw_sk)
raw_v4_input(skb, skb->nh.iph, hash);
if ((ipprot = rcu_dereference(inet_protos[hash])) != NULL) {
int ret;
if (!ipprot->no_policy &&
!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
kfree_skb(skb);
goto out;
}
ret = ipprot->handler(skb);
if (ret < 0) {
protocol = -ret;
goto resubmit;
}
IP_INC_STATS_BH(IPSTATS_MIB_INDELIVERS);
} else {
if (!raw_sk) {
if (xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
IP_INC_STATS_BH(IPSTATS_MIB_INUNKNOWNPROTOS);
icmp_send(skb, ICMP_DEST_UNREACH,
ICMP_PROT_UNREACH, 0);
}
} else
IP_INC_STATS_BH(IPSTATS_MIB_INDELIVERS);
kfree_skb(skb);
}
}
out:
rcu_read_unlock();
return 0;
}
