tango-kni/kni_replace.c

#include <stdio.h>   
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include "kni_replace.h"
#include "kni_entry.h"



extern "C" int sendpacket_do_checksum(unsigned char* buf,int protocol,int len);



int kni_get_replace(int cfg_id,int ser_def_len,char* service_defined,struct kni_replace_info* replace_info)
{
	int original_len =0;
	int replace_len = 0;
	char* original = NULL;
	char* replace = NULL;
	char* tmp = NULL;
	
	tmp = kni_memncasemem(service_defined, ser_def_len,(char*)"zone=pkt_payload;substitute=", strlen("zone=pkt_payload;substitute="));
	if(tmp == NULL)
	{		
		MESA_handle_runtime_log(g_kni_comminfo.logger,RLOG_LV_FATAL,"REPLACE","service defined error!cfg_id:%d,region:%s",cfg_id,service_defined);
		return -1;
	}

	

	original = kni_memncasemem(service_defined, ser_def_len,(char*)"/", strlen("/"));
	if(original == NULL) 
	{
		MESA_handle_runtime_log(g_kni_comminfo.logger,RLOG_LV_FATAL,"REPLACE","service defined error!cfg_id:%d,region:%s",cfg_id,service_defined);
		return -1;
	}

	original += 1;
	original_len = strlen(original);

	replace = kni_memncasemem(original+1,original_len-1,(char*)"/", strlen("/"));
	if(replace == NULL)
	{
		MESA_handle_runtime_log(g_kni_comminfo.logger,RLOG_LV_FATAL,"REPLACE","service defined error!cfg_id:%d,region:%s",cfg_id,service_defined);
		return -1;
	}

	replace += 1;
	replace_len = strlen(replace);

	replace_info->original_len = replace - original -1;
	assert((int)sizeof(replace_info->find)>=replace_info->original_len);
	memcpy(replace_info->find,original,replace_info->original_len);

	replace_info->replace_len = replace_len;
	assert((int)sizeof(replace_info->replace)>=replace_info->replace_len);
	memcpy(replace_info->replace,replace,replace_info->replace_len);

	return 0;
	
}


int kni_build_send_ipv4(unsigned char dir,int thread_seq,struct ip* a_packet,struct kni_pme_info* pmeinfo,struct kni_replace_info* replace_info)
{
//	char ret = APP_STATE_DROPPKT | APP_STATE_DROPME;
	char ret = APP_STATE_DROPPKT | APP_STATE_GIVEME;

	struct ip* iphdr = NULL;
	struct kni_udp_hdr* udphdr = NULL;

	char* payload = ((char*)a_packet+4*(a_packet->ip_hl)); 
	unsigned short iplen = ntohs(a_packet->ip_len);
	unsigned short udplen = 0;
	
	int payload_len = iplen - 4*(a_packet->ip_hl);
	
	char* pos = NULL;
	char* sendbuf = NULL;
	unsigned short sendbuf_len = 0;
	int tmp_len = 0;

	pos = (char*)memmem(payload, payload_len,(replace_info->find), replace_info->original_len);
	if(pos != NULL)
	{
		sendbuf_len = iplen - replace_info->original_len + replace_info->replace_len;
		sendbuf = (char*)malloc(sendbuf_len);

		memcpy(sendbuf,(char*)a_packet,(pos-(char*)a_packet));
		tmp_len += pos-(char*)a_packet;

		memcpy(sendbuf+tmp_len,replace_info->replace,replace_info->replace_len);
		tmp_len += replace_info->replace_len;

		memcpy(sendbuf+tmp_len,(pos+replace_info->original_len),sendbuf_len-tmp_len);

		iphdr = (struct ip*)sendbuf;
		iphdr->ip_len = ntohs(sendbuf_len);

//		if(iphdr->ip_p == PROTO_TYPE_UDP)
		{
			udphdr = (struct kni_udp_hdr*)(sendbuf + 4*(iphdr->ip_hl));
			udplen = ntohs(udphdr->uh_ulen);
			udphdr->uh_ulen = htons(udplen - replace_info->original_len + replace_info->replace_len);
		}

		sendpacket_do_checksum((unsigned char*)sendbuf,IPPROTO_UDP,(sendbuf_len-4*(iphdr->ip_hl)));
		sendpacket_do_checksum((unsigned char*)sendbuf,IPPROTO_IP,sizeof(struct ip));

		MESA_sendpacket_iplayer(thread_seq,sendbuf,sendbuf_len,dir);

		free(sendbuf);
		sendbuf = NULL;
	}

	return ret;
	
}



int kni_build_send_ipv6(unsigned char dir,int thread_seq,struct kni_ipv6_hdr* a_packet,struct kni_pme_info* pmeinfo,struct kni_replace_info* replace_info)
{
	char ret = APP_STATE_DROPPKT | APP_STATE_DROPME;

	return ret;

}



char kni_process_replace(unsigned char dir,int thread_seq,const void* a_packet,struct kni_pme_info* pmeinfo)
{
	if(g_kni_switch_info.replace_switch == 0)
	{
		return APP_STATE_DROPME;
	}


//	kni_filestate2_set(thread_seq,FS_REPLACE,0,1);

//	char ret = APP_STATE_DROPPKT | APP_STATE_DROPME;
	char ret = APP_STATE_DROPPKT | APP_STATE_GIVEME;

	struct kni_replace_info replace_info;
	memset(&replace_info,0,sizeof(struct kni_replace_info));

	if(kni_get_replace(pmeinfo->cfg_id,pmeinfo->ser_def_len,pmeinfo->service_defined,&replace_info) < 0)
	{
		kni_log_debug(RLOG_LV_FATAL,(char*)"REPLACE",a_packet,(char*)"kni_get_replace error");
		return APP_STATE_DROPME;
	}

	kni_log_debug(RLOG_LV_FATAL,(char*)"REPLACE",a_packet,(char*)"config id:%d,original:%s,replace:%s",pmeinfo->cfg_id,replace_info.find,replace_info.replace);

	if(*(char*)a_packet == 0x45)
	{
		ret = kni_build_send_ipv4(dir,thread_seq,(struct ip*)a_packet,pmeinfo,&replace_info);
	}
	else 
	{
		ret = kni_build_send_ipv6(dir,thread_seq,(struct kni_ipv6_hdr*)a_packet,pmeinfo,&replace_info);
	}

//20181030 modify for muti replace
	Maat_clean_status(&(pmeinfo->mid));
	pmeinfo->ipsscan_action = KNI_ACTION_NONE;
//end
	

	return ret;

}