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#include <stdio.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <string.h>
#include "tsg_entry.h"
#include "tsg_protocol_common.h"
#define IPV4_TYPE 1 //ADDR_TYPE_IPV4 ==1 , 取的enum 0x0800
#define IPV6_TYPE 2 //ADDR_TYPE_IPV6 ==2 0x86dd
#define TCP_TYPE 0x06
#define UDP_TYPE 0x11
#define ICMP_PROTOCOL_TYPE 0x01 //ipv4 icmp proctocol
#define ICMPV6_PROTOCAL_TYPE 0x3a //ipv6 icmpv6 protocl
#define ICMPV4_UNREACHABLE 0x03
#define ICMPV4_PORT_UNREACHABLE 0x03
#define ICMPV4_ADMINISTRATIVELY_PROHIBITED 0x0d
#define ICMPV6_UNREACHABLE 0x01
#define ICMPV6_PORT_UNREACHABLE 0X04
#define ICMPV6_ADMINISTRATIVELY_PROHIBITED 0x01
#define MAC_LEN 6
#define MAC_LEN_2 ((MAC_LEN)+(MAC_LEN))
#define ETH_IP_TYPE_LEN 2
#define ETH_LEN ((MAC_LEN_2)+(ETH_IP_TYPE_LEN))
#define TCP_MAX_LEN 60
#define ICMP_IPV4_TCP_MAX_LEN 44 //64-20 = 44
#define IPV4_SHAM_FIXED_LEN 12
#define IPV4_LEN 20
#define IPV4_IP_LEN 4
#define IPV4_IP_LEN_INDEX 2 //eth_len(14)+ ip_len_index(2)
#define IPV6_LEN 40
#define IPV6_IP_LEN 16
#define IPV6_IP_PAYLOAD_INDEX 4 // ipv6_payload_index(4)
#define ICMP_IPV4_PROTOCOL_TYPE_LEN 24
#define ICMP_HEAD_LEN 8
#define ICMPV4_SOURCE_MAX_LEN 64
#define ICMPV4_MAX_LEN ((ICMPV4_SOURCE_MAX_LEN)+(ICMP_HEAD_LEN))
#define IPV6_PESUDO_HEAD_LEN 40
#define ICMP_MAX_LEN 65535
#define ICMP_SRCPACKET_MAX_LEN 548 // 548 == ipv4(max_len 576)-ip_len(20)-icmp_head_len(8)
#define ICMPV6_SRCPACKET_MAX_LEN 1232 // 1232 == ipv6(max_len 1280)-ipv6_len(40)-icmp_head_len(8)
#define ICMPV6_MTU 1280
typedef struct icmpv4{
char type;
char code;
short checksum;
char un_user[4];
char srcPacket[ICMPV6_SRCPACKET_MAX_LEN];
}icmpv4_st, icmpv6_st;
short in_checksum(void *pkg, int size)
{
int nleft = size;
int sum = 0;
unsigned short *w = (unsigned short *)pkg;
unsigned short answer = 0;
while (nleft > 1)
{
sum += *w++;
nleft -= 2;
}
if (nleft == 1)
{
* (unsigned char *) (&answer) = *(unsigned char *)w;
sum += answer;
}
while (sum >> 16){
sum = (sum & 0xFFFF) + (sum >> 16);
}
answer = ~sum &0xffff;
return answer;
}
static void format_icmpv4(const char *raw_pkt, char *buf, int *len){
char ipv4[IPV4_LEN] = {0};
icmpv4_st icmpst = {0};
short src_ipv4_total_len = 0;
short icmpv4_complete_len = 0;
short icmp_len = 0;
short icmp_srcpacket_len = 0;
short icmp_start_len = IPV4_LEN;
short ipv4_total_len = 0;
short ipv4_checksum = 0;
short sip_len = 12; //skip sip start index
short dip_len = 16; //skip dip start index
memcpy(&src_ipv4_total_len, &raw_pkt[IPV4_IP_LEN_INDEX], sizeof(short));
src_ipv4_total_len = htons(src_ipv4_total_len);
//src_packet_len = src_ipv4_total_len + ETH_LEN;
if(src_ipv4_total_len >= ICMP_SRCPACKET_MAX_LEN){
icmp_srcpacket_len = ICMP_SRCPACKET_MAX_LEN;
}else{
icmp_srcpacket_len = src_ipv4_total_len;
}
icmp_len = icmp_srcpacket_len + ICMP_HEAD_LEN;
ipv4_total_len = icmp_len + IPV4_LEN;
icmpv4_complete_len = IPV4_LEN + icmp_len;
//format icmp information
memset(&icmpst, 0, sizeof(icmpv4_st));
memcpy(icmpst.srcPacket, raw_pkt, icmp_srcpacket_len); //
icmpst.type = ICMPV4_UNREACHABLE;
icmpst.code = ICMPV4_ADMINISTRATIVELY_PROHIBITED;
icmpst.checksum = in_checksum((void*)&icmpst, icmp_len);
//format ipv4
memcpy(ipv4, raw_pkt, IPV4_LEN); //copy source data
memcpy(&ipv4[12], &raw_pkt[dip_len], IPV4_IP_LEN); //get sip
memcpy(&ipv4[16], &raw_pkt[sip_len], IPV4_IP_LEN); //get dip
ipv4[9] = ICMP_PROTOCOL_TYPE; //set ipv4 protocol type (0x01 == ICMP)
ipv4_total_len = htons(ipv4_total_len);
memcpy(&ipv4[2], &ipv4_total_len, sizeof(short)); //format ipv4 len
memset(&ipv4[10], 0, sizeof(short)); //empty checksum data
ipv4_checksum = in_checksum(ipv4, IPV4_LEN); //calc ipv4 checksum
memcpy(&ipv4[10], &ipv4_checksum, sizeof(short)); //format checksum
//format complete icmpv4 packet
memcpy(buf, ipv4, IPV4_LEN);
memcpy(&buf[icmp_start_len], &icmpst, icmp_len);
*len = icmpv4_complete_len;
return;
}
static void format_icmpv6(const char *data, char *buf, int *len){
char checksum_str[ICMPV6_MTU] = {0};
char ipv6[IPV6_LEN] = {0};
icmpv6_st icmpst = {0};
short src_ipv6_total_len = 0;
short icmpv6_complete_len = 0;
short icmp_len = 0;
short icmp_srcpacket_len = 0;
short icmp_start_len = IPV6_LEN;
short checksum_len = 0;
short sip_len = 8; //skip sip start index
short dip_len = 24; //skip dip start index, 16+8 == 24
short ipv6_ip2 = IPV6_IP_LEN + IPV6_IP_LEN;
short payload_len = 0;
short fill_icmp_len = 0;
int checksum_payload_len = 0;
memcpy(&src_ipv6_total_len, &data[IPV6_IP_PAYLOAD_INDEX], sizeof(short)); //get ipv6_payload_len
src_ipv6_total_len = htons(src_ipv6_total_len) + IPV6_LEN;
if(src_ipv6_total_len >= ICMPV6_SRCPACKET_MAX_LEN){
icmp_srcpacket_len = ICMPV6_SRCPACKET_MAX_LEN;
}else{
icmp_srcpacket_len = src_ipv6_total_len;
}
icmp_len = icmp_srcpacket_len + ICMP_HEAD_LEN;
icmpv6_complete_len = IPV6_LEN + icmp_len;
checksum_len = icmp_len + IPV6_PESUDO_HEAD_LEN;
payload_len = htons(icmp_len);
//format ipv6
memcpy(ipv6, data, IPV6_LEN); //copy source ipv6 data
memcpy(&ipv6[8], &data[dip_len], IPV6_IP_LEN); //get sip
memcpy(&ipv6[24],&data[sip_len], IPV6_IP_LEN); //get dip
memcpy(&ipv6[4], &payload_len, sizeof(short)); //format ipv6 payload
ipv6[6] = ICMPV6_PROTOCAL_TYPE; //format ipv6 protocol (icmpv6 == 0X3a);
//format icmp
memset(&icmpst, 0, sizeof(icmpv6_st));
icmpst.type = ICMPV6_UNREACHABLE;
icmpst.code = ICMPV6_ADMINISTRATIVELY_PROHIBITED;
memcpy(icmpst.srcPacket, data, icmp_srcpacket_len);
//补充为4字节
checksum_payload_len = htonl((int)icmp_len);
fill_icmp_len = icmp_len % 4;
if( fill_icmp_len > 0){
icmp_len = icmp_len + (4-fill_icmp_len);
checksum_len = checksum_len + (4-fill_icmp_len);
}
//calc icmpv6 checksum
memcpy(checksum_str, &icmpst, icmp_len);
memcpy(&checksum_str[icmp_len], &ipv6[8], ipv6_ip2);
memcpy(&checksum_str[icmp_len+ipv6_ip2], &checksum_payload_len, sizeof(int));
checksum_str[icmp_len+ipv6_ip2+7] = ICMPV6_PROTOCAL_TYPE;
icmpst.checksum = in_checksum(checksum_str, checksum_len);
//format complete icmpv6 packet
memcpy(buf, ipv6, IPV6_LEN);
memcpy(&buf[icmp_start_len], &icmpst, icmp_len);
*len = icmpv6_complete_len;
return;
}
static void format_icmp(const char *raw_pkt, char *icmp_buf, int *icmp_len, int ip_type){
if(IPV4_TYPE == ip_type) {
format_icmpv4(raw_pkt, icmp_buf, icmp_len);
} else{ //IPV6_TYPE
format_icmpv6(raw_pkt, icmp_buf, icmp_len);
}
return;
}
unsigned char send_icmp_unreachable(const struct streaminfo *a_stream, const void *raw_pkt)
{
char icmp_buf[ICMP_MAX_LEN];
unsigned char raw_route_dir = 0;
int icmp_len = 0;
if(a_stream == NULL){
return STATE_DROPPKT;
}
if((a_stream->curdir==DIR_S2C)||(raw_pkt==NULL)){
return STATE_DROPPKT;
}
format_icmp((char *)raw_pkt, icmp_buf, &icmp_len, a_stream->addr.addrtype);
raw_route_dir = (a_stream->curdir==DIR_C2S) ? MESA_dir_reverse(a_stream->routedir) : a_stream->routedir;
return tsg_send_inject_packet(a_stream, SIO_EXCLUDE_THIS_LAYER_HDR, icmp_buf, icmp_len, raw_route_dir);
}
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