ipv6 faketcp and udp works

This commit is contained in:
wangyu- 2018-07-24 05:36:56 -05:00
parent 73daa12db1
commit 6ccd056d41
5 changed files with 311 additions and 85 deletions

@ -204,7 +204,7 @@ char* address_t::get_ip()
ip_addr[max_addr_len-1]=0;
if(get_type()==AF_INET6)
{
sprintf(s,"[%s]",ip_addr);
sprintf(s,"%s",ip_addr);
}else
{
sprintf(s,"%s",ip_addr);
@ -266,9 +266,9 @@ bool my_ip_t::equal (const my_ip_t &b) const
if(raw_ip_version==AF_INET)
{
return v4==b.v4;
}else if(raw_ip_version==AF_INET)
}else if(raw_ip_version==AF_INET6)
{
return memcmp(&v6,&b.v6,sizeof(v6));
return memcmp(&v6,&b.v6,sizeof(v6))==0;
}
assert(0==1);
return 0;
@ -280,7 +280,7 @@ char * my_ip_t::get_str1() const
{
assert(inet_ntop(AF_INET6, &v6, res,max_addr_len)!=0);
}
else if(raw_ip_version==AF_INET)
else if(raw_ip_version==AF_INET6)
{
assert(inet_ntop(AF_INET, &v4, res,max_addr_len)!=0);
}

@ -1000,6 +1000,7 @@ int server_on_raw_recv_multi() //called when server received an raw packet
raw_info_t peek_raw_info;
peek_raw_info.peek=1;
packet_info_t &peek_info=peek_raw_info.recv_info;
mylog(log_trace,"got a packet\n");
if(pre_recv_raw_packet()<0) return -1;
if(peek_raw(peek_raw_info)<0)
{

@ -69,7 +69,7 @@ char fifo_file[1000]="";
int clear_iptables=0;
int wait_xtables_lock=0;
string iptables_command0="iptables ";
string iptables_command0="iptables/ip6tables ";
string iptables_command="";
string iptables_pattern="";
int iptables_rule_added=0;
@ -864,6 +864,14 @@ void *run_keep(void *none) //called in a new thread for --keep-rule option
}
void iptables_rule() // handles -a -g --gen-add --keep-rule --clear --wait-lock
{
assert(raw_ip_version==AF_INET||raw_ip_version==AF_INET6);
if(raw_ip_version==AF_INET)
{
iptables_command0="iptables ";
}
else
iptables_command0="ip6tables ";
if(!wait_xtables_lock)
{
iptables_command=iptables_command0;

@ -80,8 +80,44 @@ struct sock_filter code_tcp[] = {
{ 0x6, 0, 0, 0x0000ffff },//9
{ 0x6, 0, 0, 0x00000000 },//10
};
/*
{ 0x28, 0, 0, 0x0000000c },
{ 0x15, 0, 8, 0x00000800 },
{ 0x30, 0, 0, 0x00000017 },
{ 0x15, 0, 6, 0x00000006 },
{ 0x28, 0, 0, 0x00000014 },
{ 0x45, 4, 0, 0x00001fff },
{ 0xb1, 0, 0, 0x0000000e },
{ 0x48, 0, 0, 0x00000010 },
{ 0x15, 0, 1, 0x0000fffe },
{ 0x6, 0, 0, 0x0000ffff },
{ 0x6, 0, 0, 0x00000000 },
*/
int code_tcp_port_index=6;
//tcpdump -i ens33 ip6 and tcp and dst port 65534 -dd
struct sock_filter code_tcp6[] = {
//{ 0x28, 0, 0, 0x0000000c },//0
//{ 0x15, 0, 5, 0x000086dd },//1
{ 0x30, 0, 0, 0x00000006 },//2
{ 0x15, 0, 3, 0x00000006 },//3
{ 0x28, 0, 0, 0x0000002a },//4
{ 0x15, 0, 1, 0x0000fffe },//5
{ 0x6, 0, 0, 0x00040000 },//6
{ 0x6, 0, 0, 0x00000000 },//7
};//note: this filter doesnt support extension headers
/*
{ 0x30, 0, 0, 0x00000014 },//2
{ 0x15, 0, 3, 0x00000006 },//3
{ 0x28, 0, 0, 0x00000038 },//4
{ 0x15, 0, 1, 0x0000fffe },//5
{ 0x6, 0, 0, 0x00040000 },//6
{ 0x6, 0, 0, 0x00000000 },//7
*/
int code_tcp6_port_index=3;
struct sock_filter code_udp[] = {
//{ 0x5, 0, 0, 0x00000001 },
//{ 0x5, 0, 0, 0x00000000 },
@ -96,6 +132,20 @@ struct sock_filter code_udp[] = {
{ 0x6, 0, 0, 0x00000000 },
};
int code_udp_port_index=6;
struct sock_filter code_udp6[] = {
// { 0x28, 0, 0, 0x0000000c },
// { 0x15, 0, 5, 0x000086dd },
{ 0x30, 0, 0, 0x00000006 },
{ 0x15, 0, 3, 0x00000011 },
{ 0x28, 0, 0, 0x0000002a },
{ 0x15, 0, 1, 0x0000fffe },
{ 0x6, 0, 0, 0x00040000 },
{ 0x6, 0, 0, 0x00000000 },
};
int code_udp6_port_index=3;
struct sock_filter code_icmp[] = {
//{ 0x5, 0, 0, 0x00000001 },
//{ 0x5, 0, 0, 0x00000000 },
@ -186,6 +236,7 @@ packet_info_t::packet_info_t()
int init_raw_socket()
{
assert(raw_ip_version==AF_INET||raw_ip_version==AF_INET6);
g_ip_id_counter=get_true_random_number()%65535;
if(lower_level==0)
@ -198,7 +249,7 @@ int init_raw_socket()
myexit(1);
}
/*
/*ETH_P_IP
int one = 1;
const int *val = &one;
if (setsockopt (raw_send_fd, IPPROTO_IP, IP_HDRINCL, val, sizeof (one)) < 0) {
@ -246,7 +297,10 @@ int init_raw_socket()
//raw_fd = socket(AF_PACKET, SOCK_DGRAM, htons(ETH_P_ALL));
raw_recv_fd= socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
if(raw_ip_version==AF_INET)
raw_recv_fd= socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
else
raw_recv_fd= socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IPV6));
//ETH_P_IP doesnt read outgoing packets
// https://stackoverflow.com/questions/20264895/eth-p-ip-is-not-working-as-expected-i-can-only-receive-incoming-packets
// to capture both incoming and outgoing packets use ETH_P_ALL
@ -265,7 +319,10 @@ int init_raw_socket()
assert(init_ifindex(dev,raw_recv_fd,index)==0);
bind_address.sll_family = AF_PACKET;
bind_address.sll_protocol = htons(ETH_P_ALL);
if(raw_ip_version==AF_INET)
bind_address.sll_protocol = htons(ETH_P_IP);
else
bind_address.sll_protocol = htons(ETH_P_IPV6);
bind_address.sll_ifindex = index;
if(bind(raw_recv_fd, (struct sockaddr *)&bind_address, sizeof(bind_address))==-1)
@ -304,6 +361,7 @@ int init_raw_socket()
void init_filter(int port)
{
sock_fprog bpf;
assert(raw_ip_version==AF_INET||raw_ip_version==AF_INET6);
if(raw_mode==mode_faketcp||raw_mode==mode_udp)
{
filter_port=port;
@ -313,15 +371,31 @@ void init_filter(int port)
//code_tcp[8].k=code_tcp[10].k=port;
if(raw_mode==mode_faketcp)
{
bpf.len = sizeof(code_tcp)/sizeof(code_tcp[0]);
code_tcp[code_tcp_port_index].k=port;
bpf.filter = code_tcp;
if(raw_ip_version==AF_INET)
{
bpf.len = sizeof(code_tcp)/sizeof(code_tcp[0]);
code_tcp[code_tcp_port_index].k=port;
bpf.filter = code_tcp;
}else
{
bpf.len = sizeof(code_tcp6)/sizeof(code_tcp6[0]);
code_tcp6[code_tcp6_port_index].k=port;
bpf.filter = code_tcp6;
}
}
else if(raw_mode==mode_udp)
{
bpf.len = sizeof(code_udp)/sizeof(code_udp[0]);
code_udp[code_udp_port_index].k=port;
bpf.filter = code_udp;
if(raw_ip_version==AF_INET)
{
bpf.len = sizeof(code_udp)/sizeof(code_udp[0]);
code_udp[code_udp_port_index].k=port;
bpf.filter = code_udp;
}else
{
bpf.len = sizeof(code_udp6)/sizeof(code_udp6[0]);
code_udp6[code_udp6_port_index].k=port;
bpf.filter = code_udp6;
}
}
else if(raw_mode==mode_icmp)
{
@ -661,41 +735,64 @@ int send_raw_ip(raw_info_t &raw_info,const char * payload,int payloadlen)
return 0;
}
struct iphdr *iph = (struct iphdr *) send_raw_ip_buf;
memset(iph,0,sizeof(iphdr));
iph->ihl = sizeof(iphdr)/4; //we dont use ip options,so the length is just sizeof(iphdr)
iph->version = 4;
iph->tos = 0;
if(lower_level)
uint16_t ip_tot_len;
if(raw_ip_version==AF_INET)
{
//iph->id=0;
iph->id = htons (g_ip_id_counter++); //Id of this packet
struct iphdr *iph = (struct iphdr *) send_raw_ip_buf;
memset(iph,0,sizeof(iphdr));
iph->ihl = sizeof(iphdr)/4; //we dont use ip options,so the length is just sizeof(iphdr)
iph->version = 4;
iph->tos = 0;
if(lower_level)
{
//iph->id=0;
iph->id = htons (g_ip_id_counter++); //Id of this packet
}
else//no need to else?
{
iph->id = htons (g_ip_id_counter++); //Id of this packet
//iph->id = 0; //Id of this packet ,kernel will auto fill this if id is zero ,or really?????// todo //seems like there is a problem
}
iph->frag_off = htons(0x4000); //DF set,others are zero
// iph->frag_off = htons(0x0000); //DF set,others are zero
iph->ttl = (unsigned char)ttl_value;
iph->protocol = send_info.protocol;
iph->check = 0; //Set to 0 before calculating checksum
iph->saddr = send_info.new_src_ip.v4; //Spoof the source ip address
iph->daddr = send_info.new_dst_ip.v4;
ip_tot_len=sizeof (struct iphdr)+payloadlen;
if(lower_level)iph->tot_len = htons(ip_tot_len); //this is not necessary ,kernel will always auto fill this //http://man7.org/linux/man-pages/man7/raw.7.html
else
iph->tot_len = 0;
memcpy(send_raw_ip_buf+sizeof(iphdr) , payload, payloadlen);
if(lower_level) iph->check =
csum ((unsigned short *) send_raw_ip_buf, iph->ihl*4); //this is not necessary ,kernel will always auto fill this
else
iph->check=0;
}
else
iph->id = htons (g_ip_id_counter++); //Id of this packet
//iph->id = 0; //Id of this packet ,kernel will auto fill this if id is zero ,or really?????// todo //seems like there is a problem
{
assert(raw_ip_version==AF_INET6);
iph->frag_off = htons(0x4000); //DF set,others are zero
// iph->frag_off = htons(0x0000); //DF set,others are zero
iph->ttl = (unsigned char)ttl_value;
iph->protocol = send_info.protocol;
iph->check = 0; //Set to 0 before calculating checksum
iph->saddr = send_info.new_src_ip.v4; //Spoof the source ip address
iph->daddr = send_info.new_dst_ip.v4;
struct my_ip6hdr *ip6h = (struct my_ip6hdr *) send_raw_ip_buf;
memset(ip6h,0,sizeof(my_ip6hdr));
uint16_t ip_tot_len=sizeof (struct iphdr)+payloadlen;
if(lower_level)iph->tot_len = htons(ip_tot_len); //this is not necessary ,kernel will always auto fill this //http://man7.org/linux/man-pages/man7/raw.7.html
else
iph->tot_len = 0;
ip6h->version=6;
ip6h->payload_len=htons(payloadlen);
ip6h->next_header=send_info.protocol;
ip6h->hop_limit=(unsigned char)ttl_value;
ip6h->src=send_info.new_src_ip.v6;
ip6h->dst=send_info.new_dst_ip.v6;
memcpy(send_raw_ip_buf+sizeof(iphdr) , payload, payloadlen);
if(lower_level) iph->check =
csum ((unsigned short *) send_raw_ip_buf, iph->ihl*4); //this is not necessary ,kernel will always auto fill this
else
iph->check=0;
ip_tot_len=sizeof (struct my_ip6hdr)+payloadlen;
memcpy(send_raw_ip_buf+sizeof(my_ip6hdr) , payload, payloadlen);
}
return send_raw_packet(raw_info,send_raw_ip_buf,ip_tot_len);
@ -772,7 +869,7 @@ int recv_raw_ip(raw_info_t &raw_info,char * &payload,int &payloadlen)
iphdr * iph;
ip6_hdr * ip6h;
my_ip6hdr * ip6h;
int flag=0;
//int recv_len = recvfrom(raw_recv_fd, recv_raw_ip_buf, max_data_len+1, flag ,(sockaddr*)&saddr , &saddr_size);
@ -784,8 +881,8 @@ int recv_raw_ip(raw_info_t &raw_info,char * &payload,int &payloadlen)
mylog(log_trace,"raw_packet_len <1, dropped\n");
return -1;
}
iph = (struct iphdr *) (ip_begin); //just use the iphdr here to get the first 4bit
ip6h= (struct ip6_hdr *) (ip_begin);
iph = (struct iphdr *) (ip_begin);
ip6h= (struct my_ip6hdr *) (ip_begin);
if(raw_ip_version==AF_INET)
{
if(iph->version!=4)
@ -802,12 +899,12 @@ int recv_raw_ip(raw_info_t &raw_info,char * &payload,int &payloadlen)
else
{
assert(raw_ip_version==AF_INET6);
if(iph->version!=6)
if(ip6h->version!=6)
{
mylog(log_trace,"expect ipv6 packet, but got something else: %02x\n",iph->version);
mylog(log_trace,"expect ipv6 packet, but got something else: %02x\n",ip6h->version);
return -1;
}
if(raw_packet_len<(int)sizeof(ip6_hdr))
if(raw_packet_len<(int)sizeof(my_ip6hdr))
{
mylog(log_trace,"raw_packet_len<sizeof(ip6_hdr)\n");
return -1;
@ -839,11 +936,11 @@ int recv_raw_ip(raw_info_t &raw_info,char * &payload,int &payloadlen)
else
{
//todo flow id
recv_info.new_src_ip.v6=ip6h->ip6_src;
recv_info.new_dst_ip.v6=ip6h->ip6_dst;
recv_info.new_src_ip.v6=ip6h->src;
recv_info.new_dst_ip.v6=ip6h->dst;
iphdrlen=40;
recv_info.protocol=ip6h->ip6_nxt; //todo handle extension headers;
ip_len=ntohs(ip6h->ip6_plen);
recv_info.protocol=ip6h->next_header; //todo handle extension headers;
ip_len=ntohs(ip6h->payload_len)+iphdrlen;
}
@ -1010,14 +1107,13 @@ int send_raw_udp(raw_info_t &raw_info, const char * payload, int payloadlen)
udphdr *udph=(struct udphdr *) (send_raw_udp_buf);
memset(udph,0,sizeof(udphdr));
struct pseudo_header tmp_header={0};
struct pseudo_header *psh = &tmp_header;
udph->source = htons(send_info.src_port);
udph->dest = htons(send_info.dst_port);
int udp_tot_len=payloadlen+sizeof(udphdr);
if(udp_tot_len>65535)
{
mylog(log_debug,"invalid len\n");
@ -1028,15 +1124,39 @@ int send_raw_udp(raw_info_t &raw_info, const char * payload, int payloadlen)
memcpy(send_raw_udp_buf+sizeof(udphdr),payload,payloadlen);
psh->source_address = send_info.new_src_ip.v4;
psh->dest_address = send_info.new_dst_ip.v4;
psh->placeholder = 0;
psh->protocol = IPPROTO_UDP;
psh->tcp_length = htons(uint16_t(udp_tot_len));
int csum_size = udp_tot_len ;
udph->check = csum_with_header((char *)psh,sizeof(pseudo_header), (unsigned short*) send_raw_udp_buf, csum_size);
if(raw_ip_version==AF_INET)
{
pseudo_header v4;
struct pseudo_header *psh = &v4;
psh->source_address = send_info.new_src_ip.v4;
psh->dest_address = send_info.new_dst_ip.v4;
psh->placeholder = 0;
psh->protocol = IPPROTO_UDP;
psh->tcp_length = htons(udp_tot_len);
udph->check = csum_with_header((char *)psh,sizeof(pseudo_header), (unsigned short*) send_raw_udp_buf, udp_tot_len);
}
else
{
pseudo_header6 v6;
struct pseudo_header6 *psh = &v6;
psh->src=send_info.new_src_ip.v6;
psh->dst=send_info.new_dst_ip.v6;
psh->next_header=IPPROTO_UDP;
psh->tcp_length=htons(udp_tot_len);
psh->placeholder1 = 0;
psh->placeholder2 = 0;
udph->check = csum_with_header((char *)psh,sizeof(pseudo_header6), (unsigned short*) send_raw_udp_buf, udp_tot_len);
}
if(send_raw_ip(raw_info,send_raw_udp_buf,udp_tot_len)!=0)
{
@ -1060,9 +1180,6 @@ int send_raw_tcp(raw_info_t &raw_info,const char * payload, int payloadlen) {
memset(tcph,0,sizeof(tcphdr));
pseudo_header tmp_header={0};
struct pseudo_header *psh = &tmp_header;
//TCP Header
tcph->source = htons(send_info.src_port);
tcph->dest = htons(send_info.dst_port);
@ -1148,19 +1265,37 @@ int send_raw_tcp(raw_info_t &raw_info,const char * payload, int payloadlen) {
char *tcp_data = send_raw_tcp_buf+ + tcph->doff * 4;
memcpy(tcp_data, payload, payloadlen);
psh->source_address = send_info.new_src_ip.v4;
psh->dest_address = send_info.new_dst_ip.v4;
psh->placeholder = 0;
psh->protocol = IPPROTO_TCP;
psh->tcp_length = htons(tcph->doff * 4 + payloadlen);
int csum_size = tcph->doff*4 + payloadlen;
tcph->check = csum_with_header((char *)psh,sizeof(pseudo_header), (unsigned short*) send_raw_tcp_buf, csum_size);
int tcp_totlen=tcph->doff*4 + payloadlen;
if(raw_ip_version==AF_INET)
{
pseudo_header v4;
struct pseudo_header *psh = &v4;
psh->source_address = send_info.new_src_ip.v4;
psh->dest_address = send_info.new_dst_ip.v4;
psh->placeholder = 0;
psh->protocol = IPPROTO_TCP;
psh->tcp_length = htons(tcph->doff * 4 + payloadlen);
tcph->check = csum_with_header((char *)psh,sizeof(pseudo_header), (unsigned short*) send_raw_tcp_buf, tcp_totlen);
}
else
{
pseudo_header6 v6;
struct pseudo_header6 *psh = &v6;
psh->src=send_info.new_src_ip.v6;
psh->dst=send_info.new_dst_ip.v6;
psh->next_header=IPPROTO_TCP;
psh->tcp_length=htons(tcph->doff * 4 + payloadlen);
psh->placeholder1 = 0;
psh->placeholder2 = 0;
tcph->check = csum_with_header((char *)psh,sizeof(pseudo_header6), (unsigned short*) send_raw_tcp_buf, tcp_totlen);
}
if(send_raw_ip(raw_info,send_raw_tcp_buf,tcp_totlen)!=0)
{
return -1;
@ -1450,6 +1585,7 @@ int recv_raw_udp(raw_info_t &raw_info, char *&payload, int &payloadlen)
//memcpy(recv_raw_udp_buf+ sizeof(struct pseudo_header) , ip_payload , ip_payloadlen);
/*
pseudo_header tmp_header={0};
struct pseudo_header *psh=&tmp_header ;
@ -1461,6 +1597,38 @@ int recv_raw_udp(raw_info_t &raw_info, char *&payload, int &payloadlen)
int csum_len=ip_payloadlen;
uint16_t udp_chk = csum_with_header((char *)psh,sizeof(pseudo_header), (unsigned short*) ip_payload, csum_len);
*/
uint16_t udp_chk;
int csum_len=ip_payloadlen;
if(raw_ip_version==AF_INET)
{
pseudo_header tmp_header;
struct pseudo_header *psh=&tmp_header ;
psh->source_address = recv_info.new_src_ip.v4;
psh->dest_address = recv_info.new_dst_ip.v4;
psh->placeholder = 0;
psh->protocol = IPPROTO_UDP;
psh->tcp_length = htons(ip_payloadlen);
udp_chk = csum_with_header((char *)psh,sizeof(pseudo_header), (unsigned short*) ip_payload, csum_len);
}
else
{
assert(raw_ip_version==AF_INET6);
pseudo_header6 tmp_header;
struct pseudo_header6 *psh=&tmp_header ;
psh->src = recv_info.new_src_ip.v6;
psh->dst = recv_info.new_dst_ip.v6;
psh->placeholder1 = 0;
psh->placeholder2 = 0;
psh->next_header = IPPROTO_UDP;
psh->tcp_length = htons(ip_payloadlen);
udp_chk = csum_with_header((char *)psh,sizeof(pseudo_header6), (unsigned short*) ip_payload, csum_len);
}
if(udp_chk!=0)
{
@ -1597,19 +1765,37 @@ int recv_raw_tcp(raw_info_t &raw_info,char * &payload,int &payloadlen)
}
// memcpy(recv_raw_tcp_buf+ sizeof(struct pseudo_header) , ip_payload , ip_payloadlen);
uint16_t tcp_chk;
int csum_len=ip_payloadlen;
if(raw_ip_version==AF_INET)
{
pseudo_header tmp_header;
struct pseudo_header *psh=&tmp_header ;
pseudo_header tmp_header;
struct pseudo_header *psh=&tmp_header ;
psh->source_address = recv_info.new_src_ip.v4;
psh->dest_address = recv_info.new_dst_ip.v4;
psh->placeholder = 0;
psh->protocol = IPPROTO_TCP;
psh->tcp_length = htons(ip_payloadlen);
psh->source_address = recv_info.new_src_ip.v4;
psh->dest_address = recv_info.new_dst_ip.v4;
psh->placeholder = 0;
psh->protocol = IPPROTO_TCP;
psh->tcp_length = htons(ip_payloadlen);
tcp_chk = csum_with_header((char *)psh,sizeof(pseudo_header), (unsigned short*) ip_payload, csum_len);
}
else
{
assert(raw_ip_version==AF_INET6);
int csum_len=ip_payloadlen;
uint16_t tcp_chk = csum_with_header((char *)psh,sizeof(pseudo_header), (unsigned short*) ip_payload, csum_len);
pseudo_header6 tmp_header;
struct pseudo_header6 *psh=&tmp_header ;
psh->src = recv_info.new_src_ip.v6;
psh->dst = recv_info.new_dst_ip.v6;
psh->placeholder1 = 0;
psh->placeholder2 = 0;
psh->next_header = IPPROTO_TCP;
psh->tcp_length = htons(ip_payloadlen);
tcp_chk = csum_with_header((char *)psh,sizeof(pseudo_header6), (unsigned short*) ip_payload, csum_len);
}
/*for(int i=0;i<csum_len;i++)
{
printf("<%d>",int(ip_payload[i]));

@ -30,6 +30,28 @@ extern char g_packet_buf[buf_len];
extern int g_packet_buf_len;
extern int g_packet_buf_cnt;
struct my_ip6hdr
{
#if __BYTE_ORDER == __LITTLE_ENDIAN
u_int32_t traffic_class_high:4;
u_int32_t version:4;
u_int32_t traffic_class_low:4;
u_int32_t flow_label:20;
#elif __BYTE_ORDER == __BIG_ENDIAN
u_int32_t flow_label:20;
u_int32_t traffic_class_low:4;
u_int32_t version:4;
u_int32_t traffic_class_high:4;
#else
# error "Please fix this"
#endif
u_int16_t payload_len;
unsigned char next_header;
unsigned char hop_limit;
struct in6_addr src;
struct in6_addr dst;
};
struct icmphdr
{
@ -48,6 +70,15 @@ struct pseudo_header {
u_int16_t tcp_length;
};
struct pseudo_header6 {
struct in6_addr src;
struct in6_addr dst;
u_int32_t tcp_length;
u_int16_t placeholder1;
u_int8_t placeholder2;
u_int8_t next_header;
};
struct packet_info_t //todo change this to union
{
uint8_t protocol;