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simplify csum, added tcp option parser

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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
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107
network.cpp
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@@ -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;