simplify csum, added tcp option parser

This commit is contained in:
wangyu- 2018-07-20 09:29:10 -05:00
parent 30eb96608d
commit 2e8294ab88
5 changed files with 181 additions and 18 deletions

@ -314,6 +314,46 @@ u64_t hton64(u64_t a)
}
void write_u16(char * p,u16_t w)
{
*(unsigned char*)(p + 1) = (w & 0xff);
*(unsigned char*)(p + 0) = (w >> 8);
}
u16_t read_u16(char * p)
{
u16_t res;
res = *(const unsigned char*)(p + 0);
res = *(const unsigned char*)(p + 1) + (res << 8);
return res;
}
void write_u32(char * p,u32_t l)
{
*(unsigned char*)(p + 3) = (unsigned char)((l >> 0) & 0xff);
*(unsigned char*)(p + 2) = (unsigned char)((l >> 8) & 0xff);
*(unsigned char*)(p + 1) = (unsigned char)((l >> 16) & 0xff);
*(unsigned char*)(p + 0) = (unsigned char)((l >> 24) & 0xff);
}
u32_t read_u32(char * p)
{
u32_t res;
res = *(const unsigned char*)(p + 0);
res = *(const unsigned char*)(p + 1) + (res << 8);
res = *(const unsigned char*)(p + 2) + (res << 8);
res = *(const unsigned char*)(p + 3) + (res << 8);
return res;
}
void write_u64(char * s,u64_t a)
{
assert(0==1);
}
u64_t read_u64(char * s)
{
assert(0==1);
return 0;
}
void setnonblocking(int sock) {
int opts;
opts = fcntl(sock, F_GETFL);
@ -358,6 +398,39 @@ unsigned short csum(const unsigned short *ptr,int nbytes) {//works both for big
return(answer);
}
unsigned short csum_with_header(char* header,int hlen,const unsigned short *ptr,int nbytes) {//works both for big and little endian
long sum;
unsigned short oddbyte;
short answer;
assert(hlen%2==0);
sum=0;
unsigned short * tmp= (unsigned short *)header;
for(int i=0;i<hlen/2;i++)
{
sum+=*tmp++;
}
while(nbytes>1) {
sum+=*ptr++;
nbytes-=2;
}
if(nbytes==1) {
oddbyte=0;
*((u_char*)&oddbyte)=*(u_char*)ptr;
sum+=oddbyte;
}
sum = (sum>>16)+(sum & 0xffff);
sum = sum + (sum>>16);
answer=(short)~sum;
return(answer);
}
int set_buf_size(int fd,int socket_buf_size)
{
if(force_socket_buf)

@ -64,6 +64,9 @@ typedef long long i64_t;
typedef unsigned int u32_t;
typedef int i32_t;
typedef unsigned short u16_t;
typedef short i16_t;
typedef u32_t id_t;
typedef u64_t iv_t;
@ -250,6 +253,16 @@ u32_t get_true_random_number();
u32_t get_true_random_number_nz();
u64_t ntoh64(u64_t a);
u64_t hton64(u64_t a);
void write_u16(char *,u16_t a);// network order
u16_t read_u16(char *);
void write_u32(char *,u32_t a);// network order
u32_t read_u32(char *);
void write_u64(char *,u64_t a);
u64_t read_uu64(char *);
bool larger_than_u16(uint16_t a,uint16_t b);
bool larger_than_u32(u32_t a,u32_t b);
void setnonblocking(int sock);
@ -258,6 +271,7 @@ int set_buf_size(int fd,int socket_buf_size);
void myexit(int a);
unsigned short csum(const unsigned short *ptr,int nbytes);
unsigned short csum_with_header(char* header,int hlen,const unsigned short *ptr,int nbytes);
int numbers_to_char(id_t id1,id_t id2,id_t id3,char * &data,int &len);
int char_to_numbers(const char * data,int len,id_t &id1,id_t &id2,id_t &id3);

@ -12,6 +12,8 @@ char hb_buf[buf_len];
int on_epoll_recv_event=0; //TODO, just a flag to help detect epoll infinite shoot
int server_easytcp=0;//currently only for test
int client_on_timer(conn_info_t &conn_info) //for client. called when a timer is ready in epoll
{
//keep_iptables_rule();
@ -1011,6 +1013,8 @@ int server_on_raw_recv_multi() //called when server received an raw packet
{
return 0;
}
if(server_easytcp!=0)
return 0;
raw_info_t &raw_info=tmp_raw_info;
packet_info_t &send_info=raw_info.send_info;
packet_info_t &recv_info=raw_info.recv_info;

@ -157,6 +157,7 @@ void print_help()
printf(" --disable-bpf disable the kernel space filter,most time its not necessary\n");
printf(" unless you suspect there is a bug\n");
// printf("\n");
printf(" --dev <string> bind raw socket to a device, not necessary but improves performance\n");
printf(" --sock-buf <number> buf size for socket,>=10 and <=10240,unit:kbyte,default:1024\n");
printf(" --force-sock-buf bypass system limitation while setting sock-buf\n");
printf(" --seq-mode <number> seq increase mode for faketcp:\n");

@ -910,13 +910,12 @@ int send_raw_tcp(raw_info_t &raw_info,const char * payload, int payloadlen) {
char send_raw_tcp_buf[buf_len];
//char *send_raw_tcp_buf=send_raw_tcp_buf0;
struct tcphdr *tcph = (struct tcphdr *) (send_raw_tcp_buf
+ sizeof(struct pseudo_header));
struct tcphdr *tcph = (struct tcphdr *) (send_raw_tcp_buf);
memset(tcph,0,sizeof(tcphdr));
struct pseudo_header *psh = (struct pseudo_header *) (send_raw_tcp_buf);
pseudo_header tmp_header={0};
struct pseudo_header *psh = &tmp_header;
//TCP Header
tcph->source = htons(send_info.src_port);
@ -933,7 +932,7 @@ int send_raw_tcp(raw_info_t &raw_info,const char * payload, int payloadlen) {
if (tcph->syn == 1) {
tcph->doff = 10; //tcp header size
int i = sizeof(pseudo_header)+sizeof(tcphdr);
int i = sizeof(tcphdr);
send_raw_tcp_buf[i++] = 0x02; //mss
send_raw_tcp_buf[i++] = 0x04;
send_raw_tcp_buf[i++] = 0x05;
@ -969,7 +968,7 @@ int send_raw_tcp(raw_info_t &raw_info,const char * payload, int payloadlen) {
send_raw_tcp_buf[i++] = wscale;
} else {
tcph->doff = 8;
int i = sizeof(pseudo_header)+sizeof(tcphdr);
int i = sizeof(tcphdr);
send_raw_tcp_buf[i++] = 0x01;
send_raw_tcp_buf[i++] = 0x01;
@ -1000,7 +999,7 @@ int send_raw_tcp(raw_info_t &raw_info,const char * payload, int payloadlen) {
tcph->check = 0; //leave checksum 0 now, filled later by pseudo header
tcph->urg_ptr = 0;
char *tcp_data = send_raw_tcp_buf+sizeof(struct pseudo_header) + tcph->doff * 4;
char *tcp_data = send_raw_tcp_buf+ + tcph->doff * 4;
memcpy(tcp_data, payload, payloadlen);
@ -1010,13 +1009,13 @@ int send_raw_tcp(raw_info_t &raw_info,const char * payload, int payloadlen) {
psh->protocol = IPPROTO_TCP;
psh->tcp_length = htons(tcph->doff * 4 + payloadlen);
int csum_size = sizeof(struct pseudo_header) + tcph->doff*4 + payloadlen;
int csum_size = tcph->doff*4 + payloadlen;
tcph->check = csum( (unsigned short*) send_raw_tcp_buf, csum_size);
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(send_raw_ip(raw_info,send_raw_tcp_buf+ sizeof(struct pseudo_header),tcp_totlen)!=0)
if(send_raw_ip(raw_info,send_raw_tcp_buf,tcp_totlen)!=0)
{
return -1;
}
@ -1335,13 +1334,74 @@ int recv_raw_udp(raw_info_t &raw_info, char *&payload, int &payloadlen)
return 0;
}
int parse_tcp_option(char * option_begin,char * option_end,packet_info_t &recv_info)
{
recv_info.has_ts=0;
recv_info.ts=0;
char *ptr=option_begin;
//char *option_end=tcp_begin+tcp_hdr_len;
while(ptr<option_end)
{
if(*ptr==0)
{
return 0;
}
else if(*ptr==1)
{
ptr++;
}
else if(*ptr==8)
{
if(ptr+1>=option_end)
{
mylog(log_debug,"invaild option ptr+1==option_end,for ts\n");
return -1;
}
if(*(ptr+1)!=10)
{
mylog(log_debug,"invaild ts len\n");
return -1;
}
if(ptr+10>option_end)
{
mylog(log_debug,"ptr+10>option_end for ts\n");
return -1;
}
recv_info.has_ts=1;
recv_info.ts= read_u32(ptr+2);
recv_info.ts_ack=read_u32(ptr+6);
//printf("<%d %d>!\n",recv_info.ts,recv_info.ts_ack);
//return 0;//we currently only parse ts, so just return after its found
ptr+=8;
}
else
{
if(ptr+1>=option_end)
{
mylog(log_debug,"invaild option ptr+1==option_end\n");
return -1;
}
else
{
//omit check
ptr+=*(ptr+1);
}
}
}
return 0;
}
int recv_raw_tcp(raw_info_t &raw_info,char * &payload,int &payloadlen)
{
const packet_info_t &send_info=raw_info.send_info;
packet_info_t &recv_info=raw_info.recv_info;
static char recv_raw_tcp_buf[buf_len];
//static char recv_raw_tcp_buf[buf_len];
char * ip_payload;
int ip_payloadlen;
@ -1376,9 +1436,10 @@ int recv_raw_tcp(raw_info_t &raw_info,char * &payload,int &payloadlen)
return -1;
}
memcpy(recv_raw_tcp_buf+ sizeof(struct pseudo_header) , ip_payload , ip_payloadlen);
// memcpy(recv_raw_tcp_buf+ sizeof(struct pseudo_header) , ip_payload , ip_payloadlen);
struct pseudo_header *psh=(pseudo_header *)recv_raw_tcp_buf ;
pseudo_header tmp_header;
struct pseudo_header *psh=&tmp_header ;
psh->source_address = recv_info.src_ip;
psh->dest_address = recv_info.dst_ip;
@ -1386,8 +1447,14 @@ int recv_raw_tcp(raw_info_t &raw_info,char * &payload,int &payloadlen)
psh->protocol = IPPROTO_TCP;
psh->tcp_length = htons(ip_payloadlen);
int csum_len=sizeof(struct pseudo_header)+ip_payloadlen;
uint16_t tcp_chk = csum( (unsigned short*) recv_raw_tcp_buf, csum_len);
int csum_len=ip_payloadlen;
uint16_t tcp_chk = csum_with_header((char *)psh,sizeof(pseudo_header), (unsigned short*) ip_payload, csum_len);
/*for(int i=0;i<csum_len;i++)
{
printf("<%d>",int(ip_payload[i]));
}
printf("\n");*/
if(tcp_chk!=0)
{
@ -1397,10 +1464,12 @@ int recv_raw_tcp(raw_info_t &raw_info,char * &payload,int &payloadlen)
}
char *tcp_begin=recv_raw_tcp_buf+sizeof(struct pseudo_header); //ip packet's data part
char *tcp_begin=ip_payload; //ip packet's data part
char *tcp_option=recv_raw_tcp_buf+sizeof(struct pseudo_header)+sizeof(tcphdr);
char *tcp_option=ip_payload+sizeof(tcphdr);
/*
//old ts parse code
recv_info.has_ts=0;
recv_info.ts=0;
if(tcph->doff==10)
@ -1445,7 +1514,9 @@ int recv_raw_tcp(raw_info_t &raw_info,char * &payload,int &payloadlen)
{
//mylog(log_info,"tcph->doff= %u\n",tcph->doff);
}
printf("<%d %d>\n",recv_info.ts,recv_info.ts_ack);
*/
parse_tcp_option(tcp_option,tcp_begin+tcph->doff*4,recv_info);
recv_info.ack=tcph->ack;
recv_info.syn=tcph->syn;