openwrt　内核截断重定向自组报文发送

Brickie-liu 2014-04-09 05:49:19

下边是在post挂的钩子函数一个过程，要发如果是web服务回的是psh ack我直接修改为302　fin报文,但是客户端收不到报文？



u32 reply_http_302fin_out(struct sk_buff *skb)

{

	struct iphdr *ipv4_hdr_t;

	struct tcphdr *tcp_hdr_t;

    struct ethhdr *eth_hdr_t;



	char *data_hdr_t;



	u32 eth_hdr_len = 0;

	u32 ipv4_hdr_len = 0;

	u32 tcp_hdr_len = 0;

	u32 data_len = 0;

	u32 pkt_len = 0;

	u32 ret;

	u8 packet[512]={0}; 

	struct sk_buff *skb_t;

	struct net_device *dev;

	struct iphdr *iphdr;

	struct tcphdr *tcphdr;

	struct ethhdr *ethhdr;



	

	ethhdr =  eth_hdr(skb);

	iphdr = ip_hdr(skb);

	tcphdr = tcp_hdr(skb);



	if(!ORIGIN_TCP_FLAG_PSH_ACK(tcphdr))

	{

		return 0;

	}



	eth_hdr_len = ethhdr->h_proto == htons(ETH_P_8021Q) ? ETH_HLEN + 4: ETH_HLEN;

	ipv4_hdr_len = iphdr->ihl *4;

	tcp_hdr_len = tcphdr->doff * 4;

	

	data_hdr_t = packet + eth_hdr_len + ipv4_hdr_len + tcp_hdr_len;

	

	data_len = reply_packet_buffer_data(data_hdr_t, g_portal_config.rehttp_conf.Location);

	pkt_len = eth_hdr_len + ipv4_hdr_len + tcp_hdr_len + data_len;



	skb_t = skb_copy_expand(skb,tcp_hdr_len+ipv4_hdr_len+eth_hdr_len, data_len, GFP_ATOMIC);

	if( skb_t == NULL)

	{

		goto truncation_drop;

	}



	memcpy((void *)eth_hdr(skb_t), (void *)ethhdr, tcp_hdr_len+ipv4_hdr_len+eth_hdr_len);

	memcpy((void *)eth_hdr(skb_t)+tcp_hdr_len+ipv4_hdr_len+eth_hdr_len,	data_hdr_t, data_len);



	ipv4_hdr_t = ip_hdr(skb_t);

	tcp_hdr_t = tcp_hdr(skb_t);



	

	ipv4_hdr_t->frag_off=ntohs(0x4000);

	ipv4_hdr_t->check = 0;

	ipv4_hdr_t->saddr = 0x01010101;



	tcp_hdr_t->ack_seq = htonl(ntohl(tcphdr->seq)+ data_len);

	tcp_hdr_t->psh = 1;

	tcp_hdr_t->fin= 1;



	ipv4_hdr_t->tot_len = htons( ipv4_hdr_t->ihl * 4 + tcp_hdr_t->doff * 4 + data_len);



	ip_tcp_csum(ipv4_hdr_t, tcp_hdr_t, data_len);



/*打印自组报文内容，这个没什么问题*/

	hexlog((void *)eth_hdr(skb_t), pkt_len);

	

	ret = dev_queue_xmit(skb_t);

	if(ret)

	{

		kfree_skb(skb_t);

	}



return 1;

}