106 lines
3.2 KiB
C
106 lines
3.2 KiB
C
#include <linux/errno.h>
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#include <linux/string.h>
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#include <linux/types.h>
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#include <net/net_namespace.h>
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#include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
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#include <net/netfilter/nf_conntrack_tuple.h>
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#include <net/netfilter/nf_conntrack_l3proto.h>
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#include <net/netfilter/nf_conntrack_l4proto.h>
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#include <linux/skbuff.h>
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#include <net/netfilter/nf_conntrack_core.h>
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#include "../modules/userhash/k-userhash.h"
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#include "../modules/usercfgrcv/usercfg_kinit.h"
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#include <asm-generic/int-ll64.h>
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#include <linux/netfilter.h>
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extern struct list_head hash_array[];
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extern freeauth_configure_t *kfreeauth;
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/*匹配免认证规则 */
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int judge(u_int8_t proto, __be32 sip, __be32 dip, __be16 dport )
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{
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/*免认证规则要求是http报文,http基于tcp协议 */
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if (proto != 6) return 0;
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if ((sip != kfreeauth->sip) && (dip != kfreeauth->dip)) return 0;
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if (dport != kfreeauth->dport) return 0;
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return 1;
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}
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int match_rule(const struct sk_buff *skb,u_int16_t l3num,
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struct net *net,struct nf_conntrack_tuple *tuple)
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{
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const struct nf_conntrack_l3proto *l3proto;
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const struct nf_conntrack_l4proto *l4proto;
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unsigned int nhoff; /*nhoff表示L3首部在skb中的偏移 */
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unsigned int protoff;
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u_int8_t protonum;
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unsigned int dataoff; /*dataoff表示L4首部在skb中的偏移 */
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int ret;
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int result;
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USERINFO *kresult;
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kresult = (USERINFO *)kmalloc(sizeof(USERINFO), GFP_KERNEL);
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if (NULL == kresult)
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{
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return ENOMEM;
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}
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/*获取版本号、源端口、目的端口、源IP、目的IP */
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/*nf_ct_get_tuple函数主要根据协议号调用pkt_to_tuple生成一个tuple */
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/*tcp/udp协议就是生成五元组(源ip、目的ip、源端口、目的端口、协议号)，icmp协议就是(id、code、type) */
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ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, net, tuple,l3proto, l4proto);
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if(ret == 0)
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{
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printk("resolve_normal_ct: Can't get tuple\n");
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kfree(kresult);
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return EIO;
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}
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/*1.判断用户认证成功 ——非重定向
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2.判断是否符合免认证规则 ——非重定向
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3.判断目的端口是否是80—— 重定向标记
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4.目的端口不是80的情况下，判断协议是否是DHCP和DNS，如果是DHCP和DNS——非重定向
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5.其余包 drop*/
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kresult = search_user(tuple->src.u3.ip);
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/*用户已经认证通过 */
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if(kresult != NULL)
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{
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kfree(kresult);
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return NF_ACCEPT;
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}
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/*报文匹配免认证规则 */
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result = judge(tuple->dst.protonum, tuple->src.u3.ip, tuple->dst.u3.ip, tuple->dst.u.tcp.port );
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if (result == 1)
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{
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kfree(kresult);
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return NF_ACCEPT;
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}
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/*80端口接入的HTTP报文重定向到Web Server */
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if((tuple->dst.protonum == 6) && (tuple->dst.u.tcp.port == 80))
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{
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/*打重定向Mark标记 */
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kfree(kresult);
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}
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else
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{
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/*dhcp报文 dns报文 默认放行 */
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if((tuple->dst.u.tcp.port == 67) || (tuple->dst.u.tcp.port == 68) || (tuple->dst.u.tcp.port ==53))
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{
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kfree(kresult);
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return NF_ACCEPT;
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}
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}
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kfree(kresult);
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return NF_DROP;
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}
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