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packman.c
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//*****************************************************
//*****************************************************
//
// packman.c
// Project: mptcp_proxy
//
//*****************************************************
//*****************************************************
//
// GEORG HAMPEL - Bell Labs/NJ/USA: All Rights Reserved
//
//*****************************************************
//*****************************************************
//*****************************************************
#include "mptcpproxy_util.h"
#include "packman.h"
#include "sflman.h"
#include "sessman.h"
#include "conman.h"
#include "my_checksum.h"
struct mptcp_option mptopt[10];
struct tcp_option topt[20];
//++++++++++++++++++++++++++++++++++++++++++++++++
//Filter: create_packet(..)
// packet written to buf
// returns *plen
//++++++++++++++++++++++++++++++++++++++++++++++++
void create_packet(unsigned char *buf, uint16_t *plen,
struct fourtuple *pft,
uint32_t sn, //netork format
uint32_t an, //netork format
unsigned char flags,//network format
uint16_t win, //network format
unsigned char *buf_opt,
uint16_t len_opt) {
len_opt=pad_options_buffer(buf_opt, len_opt);
uint16_t iplen = 20;
uint16_t tcplen = 20;
unsigned char offset = tcplen+len_opt;
*plen = iplen+offset;
memset(buf, 0, *plen);
//enter options
if(buf_opt)
memcpy(buf+iplen+tcplen, buf_opt, len_opt);
//tcp header
*((uint16_t*)(buf + iplen)) = htons(pft->prt_loc);
*((uint16_t*)(buf+ iplen+2)) = htons(pft->prt_rem);
*((uint32_t*)(buf+ iplen+4)) = sn;
*((uint32_t*)(buf+ iplen+8)) = an;
*(buf+ iplen+13) = flags;
*((uint16_t*)(buf+ iplen+14)) = win;
*(buf+ iplen+12) = (unsigned char) (offset<<2);//divided by 2 and leftshift4
//IP header
*buf = 69;//version 4 ^^4 + 5
*(buf+6) = 0x40;
*(buf+8) = 64;//TTL
*(buf+9) = 6;//TCP
*((uint16_t*)(buf+2)) = htons(*plen);
*((uint32_t*)(buf+12)) = htonl(pft->ip_loc);
*((uint32_t*)(buf+16)) = htonl(pft->ip_rem);
//update of both checksums
compute_checksums(buf, iplen, *plen);
add_msg("[DEBUG]from create_packet:");
print_tcp_packet(buf);
}
int create_raw_packet_send(struct fourtuple *pft,
uint8_t direction,//1:input 3:output
uint32_t sn_n, //netork format
uint32_t an_n, //netork format
unsigned char flags_n,//network format
uint16_t win_n, //network format
unsigned char *buf_opt,
uint16_t len_opt,
unsigned char *buf_pay,
uint16_t len_pay
) {
unsigned char *buf = raw_buf;
uint16_t len;
struct sockaddr_in sin;
sin.sin_family = AF_INET;
len_opt = pad_options_buffer(buf_opt, len_opt);
uint16_t iplen = 20;
uint16_t tcplen = 20;
unsigned char offset = tcplen + len_opt;
len = iplen + offset + len_pay;
memset(buf, 0, len);
//enter payload
if (buf_pay && len_pay)
memcpy(buf + iplen + tcplen + len_opt, buf_pay, len_pay);
//enter options
if (buf_opt && len_opt)
memcpy(buf + iplen + tcplen, buf_opt, len_opt);
//tcp header
if (direction == 3) {//output
*((uint16_t*)(buf + iplen)) = htons(pft->prt_loc);
*((uint16_t*)(buf + iplen + 2)) = htons(pft->prt_rem);
*((uint32_t*)(buf + 12)) = htonl(pft->ip_loc);
*((uint32_t*)(buf + 16)) = htonl(pft->ip_rem);
sin.sin_port = htons(pft->prt_rem);
sin.sin_addr.s_addr = htonl(pft->ip_rem);
}
else if (direction == 1) {//input
*((uint16_t*)(buf + iplen)) = htons(pft->prt_rem);
*((uint16_t*)(buf + iplen + 2)) = htons(pft->prt_loc);
*((uint32_t*)(buf + 12)) = htonl(pft->ip_rem);
*((uint32_t*)(buf + 16)) = htonl(pft->ip_loc);
sin.sin_port = htons(pft->prt_loc);
sin.sin_addr.s_addr = htonl(pft->ip_loc);
}
*((uint32_t*)(buf + iplen + 4)) = sn_n;
*((uint32_t*)(buf + iplen + 8)) = an_n;
*(buf + iplen + 13) = flags_n;
*((uint16_t*)(buf + iplen + 14)) = win_n;
*(buf + iplen + 12) = (unsigned char)(offset << 2);//divided by 2 and leftshift4
//IP header
*buf = 69;//version 4 ^^4 + 5
*(buf + 6) = 0x40;
*(buf + 8) = 64;//TTL
*(buf + 9) = 6;//TCP
*((uint16_t*)(buf + 2)) = htons(len);
//update of both checksums
compute_checksums(buf, iplen, len);
print_tcp_packet(buf);
int ret = sendto(raw_sd, buf, len, 0, (struct sockaddr*) &sin, sizeof(sin));
if (ret < 0)
add_err_msg("send_raw_packet returns error");
return ret;
}
void create_packet_payload(unsigned char *buf, uint16_t *plen,
struct fourtuple *pft,
uint32_t sn, //netork format
uint32_t an, //netork format
unsigned char flags,//network format
uint16_t win, //network format
unsigned char *buf_opt,
uint16_t len_opt,
unsigned char *buf_pay,
uint16_t len_pay
) {
len_opt=pad_options_buffer(buf_opt, len_opt);
uint16_t iplen = 20;
uint16_t tcplen = 20;
unsigned char offset = tcplen+len_opt;
*plen = iplen+offset+len_pay;
memset(buf, 0, *plen);
//enter payload
if(buf_pay && len_pay)
memcpy(buf+iplen+tcplen+len_opt, buf_pay, len_pay);
//enter options
if(buf_opt && len_opt)
memcpy(buf+iplen+tcplen, buf_opt, len_opt);
//tcp header
*((uint16_t*)(buf + iplen)) = htons(pft->prt_loc);
*((uint16_t*)(buf+ iplen+2)) = htons(pft->prt_rem);
*((uint32_t*)(buf+ iplen+4)) = sn;
*((uint32_t*)(buf+ iplen+8)) = an;
*(buf+ iplen+13) = flags;
*((uint16_t*)(buf+ iplen+14)) = win;
*(buf+ iplen+12) = (unsigned char) (offset<<2);//divided by 2 and leftshift4
//IP header
*buf = 69;//version 4 ^^4 + 5
*(buf+6) = 0x40;
*(buf+8) = 64;//TTL
*(buf+9) = 6;//TCP
*((uint16_t*)(buf+2)) = htons(*plen);
*((uint32_t*)(buf+12)) = htonl(pft->ip_loc);
*((uint32_t*)(buf+16)) = htonl(pft->ip_rem);
//update of both checksums
compute_checksums(buf, iplen, *plen);
print_tcp_packet(buf);
}
char* tcp_flags(u_int8_t flags)
{
static char flag_str[20];
const static char flag_strs[6][10] = { "FIN", "SYN", "RST", "PSH", "ACK", "URG" };
int i;
flag_str[0] = 0;
for (i = 0; i<6; i++) {
if ((flags >> i) & 1) {
strncat(flag_str, flag_strs[i], 3);
strncat(flag_str, ",", 1);
}
}
//log_debug("TCP flags: %s", flag_str);
return flag_str;
}
void print_tcp_packet(unsigned char *buf) {
char sip[16], dip[16];
struct ipheader* iphdr = (struct ipheader*)buf;
struct tcpheader* tcphdr = (struct tcpheader*)(buf + 20);
// u_int32_t target_ip = 0x8268e62d;
// u_int32_t target_ip2 = 0x12c2089c;
// if( htonl(iphdr->ip_dst)!=target_ip && htonl(iphdr->ip_dst)!=target_ip2 && htonl(iphdr->ip_src)!=target_ip && htonl(iphdr->ip_dst)!=target_ip)
// return;
uint16_t len_pay = ntohs(iphdr->ip_len) - (uint16_t)(iphdr->ip_h1<<2) - (uint16_t)(tcphdr->th_off<<2);
sprintIPaddr(sip, htonl(iphdr->ip_src));
sprintIPaddr(dip, htonl(iphdr->ip_dst));
log("-------------------------------------");
log("IP Header:");
log("+ Source: %s", sip);
log("+ Destination: %s", dip);
log("-------------------------------------");
log("\tTCP Header:");
log("\t+ SPort: %d", ntohs(tcphdr->th_sport));
log("\t+ DPort: %d", ntohs(tcphdr->th_dport));
log("\t+ Seq num: %08x", ntohl(tcphdr->th_seq));
log("\t+ Ack num: %08x", ntohl(tcphdr->th_ack));
log("\t+ Data offset: %d", tcphdr->th_off);
log("\t+ TCP flags: %s", tcp_flags(tcphdr->th_flags));
log("\t+ Window: %d", ntohs(tcphdr->th_win));
log("\t+ TCP checksum: %04x", ntohs(tcphdr->th_sum));
log("\t+ Urgent pointer: %04x", ntohs(tcphdr->th_urp));
log("\t+ Payload len: %d", len_pay);
log("-------------------------------------");
// if(len_pay) {
// log("\t+ Payload len: %d", len_pay);
// hex_dump(buf + (uint16_t)(iphdr->ip_h1<<2) + (uint16_t)(tcphdr->th_off<<2), len_pay);
// log("-------------------------------------");
// }
}
//++++++++++++++++++++++++++++++++++++++++++++++++
//send_raw_packet
//ip_dst, prt_dst in network format
//++++++++++++++++++++++++++++++++++++++++++++++++
int send_raw_packet(size_t sd, unsigned char *buf, uint16_t len, uint32_t ip_dst) {
//send packet on raw socket
struct sockaddr_in sin;
sin.sin_family = AF_INET;
sin.sin_port = ip_dst;
sin.sin_addr.s_addr = ip_dst;
int ret = sendto(sd, buf, len,0,(struct sockaddr*) &sin, sizeof(sin));
if (ret < 0)
add_err_msg("send_raw_packet returns error");
return ret;
}
//++++++++++++++++++++++++++++++++++++++++++++++++
//SFLMAN: send_reset_fourtuple()
// Sends sest on a certain fourtuple
//++++++++++++++++++++++++++++++++++++++++++++++++
int send_reset_fourtuple(struct fourtuple *ft, uint32_t seq_nb) {
//create ACK packet
//char opt_buf[opt_len];
uint16_t pack_len;
//append mptcp_opt_buf to packd.tcp_opt_buf; packd.tcp_opt_len is extended
unsigned char mptcp_opt_buf[4];
create_dummy_dssopt(mptcp_opt_buf);
create_packet(raw_buf, &pack_len,
ft,
htonl(seq_nb),
0,
4,//RST (4)
0,//window setting
mptcp_opt_buf,
4);//opt len
//send packet
if(send_raw_packet(raw_sd, raw_buf, pack_len, htonl(ft->ip_rem))<0)
return 0;
add_err_msg("send_reset_fourtuple:send rst packet");
return 1;
}
//++++++++++++++++++++++++++++++++++++++++++++++++
//PACKMAN: cache_packet_header: Buffers signaling packet header for retransmission purposes
//++++++++++++++++++++++++++++++++++++++++++++++++
void cache_packet_header(){
if(packd.tcplen + packd.ip4len > 120)
return;
memcpy(packd.sess->rex_buf, packd.new_buf, packd.tcplen + packd.ip4len);
packd.sess->rex_buf_len = packd.tcplen + packd.ip4len;
packd.sess->rex_ip4_len = packd.ip4len;
}
//++++++++++++++++++++++++++++++++++++++++++++++++
//copy_cached_packet:
// Copies packet buffered in session to new_buf
//++++++++++++++++++++++++++++++++++++++++++++++++
void retransmit_cached_packet_header() {
//add ipv4 header, core tcp header
memmove(packd.new_buf, packd.sess->rex_buf, packd.sess->rex_buf_len);
//copy payload of packet, if there is
if(packd.paylen > 0)
memmove(packd.new_buf + packd.sess->rex_buf_len, packd.buf + packd.ip4len + packd.tcplen, packd.paylen);
//update packd
packd.ip4len = packd.sess->rex_ip4_len;
packd.tcplen = packd.sess->rex_buf_len - packd.sess->rex_ip4_len;
packd.totlen = packd.sess->rex_buf_len + packd.paylen;
packd.pos_thead = packd.pos_i4head + packd.ip4len;
packd.pos_pay = packd.pos_i4head + packd.ip4len + packd.tcplen;
packd.ip4h = (struct ipheader*) (packd.new_buf+packd.pos_i4head);
packd.tcph = (struct tcpheader*) (packd.new_buf+packd.pos_i4head+packd.ip4len);
//add new tcp header length into packet
packd.tcph->th_off = packd.tcplen>>2;
}
//++++++++++++++++++++++++++++++++++++++++++++++++
//int parse_compact_copy_TCP_options(unsigned char *tcp_opt, uint16_t len)
// bundle a bunch of functions
//++++++++++++++++++++++++++++++++++++++++++++++++
void parse_compact_copy_TCP_options(unsigned char *tcp_opt, uint16_t len) {
//parse and compact options into topt
size_t nb_tcp_options = parse_compact_options(tcp_opt, len, topt);
//copy all parsed options (topt) to packd.tcp_opt_buf
packd.tcp_opt_len = copy_options_to_buffer(packd.tcp_opt_buf, nb_tcp_options, topt);
packd.tcp_options_compacted = 1;
}
//++++++++++++++++++++++++++++++++++++++++++++++++
//append_TCP_option
// topt is the new option and len its length
// topt is attached to the options in packet after compacting them
// If header to long, returns 0 without doing anything, otherwise 1
//++++++++++++++++++++++++++++++++++++++++++++++++
int append_TCP_option(unsigned char *tcp_opt, uint16_t *plen, unsigned char *new_tcp_opt, uint16_t new_len) {
if(*plen + new_len > 40) {
if(new_len < 40){
//only new option
snprintf(msg_buf,MAX_MSG_LENGTH, "Error:append_TCP_option: only mptcp option");
add_msg(msg_buf);
memmove(tcp_opt, new_tcp_opt, new_len);
*plen = new_len;
return 1;
}
else {
snprintf(msg_buf,MAX_MSG_LENGTH, "Error:append_TCP_option: too long");
add_msg(msg_buf);
return 0;
}
}
//append new option to tcp_opt_buf
memmove(tcp_opt + *plen, new_tcp_opt, new_len);
*plen += new_len;
return 1;
}
//++++++++++++++++++++++++++++++++++++++++++++++++
//create TPCAP option
// mpbuf points to packd.tptop_opt_buf.
// For SYN and SYN/ACK, only key_loc is provided.
// For final ACK both keys are provided
//++++++++++++++++++++++++++++++++++++++++++++++++
int create_MPcap(unsigned char *top, uint16_t *plen, uint32_t *key_loc, uint32_t *key_rem) {
unsigned char new_len = (key_rem == NULL)? 12:20;
if((*plen) + new_len > 40) {
snprintf(msg_buf,MAX_MSG_LENGTH, "Error:create_MPcap: too long");
add_msg(msg_buf);
return -1;
}
unsigned char *start = top + (*plen);
(*plen) += new_len;
*(start) = MPTCP_KIND;
*(start+1) = new_len;
*(start+2) = ( ((unsigned char) MPTCP_CAP)<<4) & 0xf0;
*(start+3) = 0x81;
*((uint32_t*) (start+4)) = key_loc[0];
*((uint32_t*) (start+8)) = key_loc[1];
if(key_rem != NULL) {
*((uint32_t*) (start+12)) = key_rem[0];//only used for ACK
*((uint32_t*) (start+16)) = key_rem[1];//only used for ACK
}
return 1;
}
//++++++++++++++++++++++++++++++++++++++++++++++++
//create_dummy_dssopt(..)
// creates mpbuf for dummy DSS
// used when terminating subflows
//++++++++++++++++++++++++++++++++++++++++++++++++
int create_dummy_dssopt(unsigned char *top){
unsigned char *start = top;
*(start) = MPTCP_KIND;
*(start+1) = 4;
*(start+2) = ( ((unsigned char) MPTCP_DSS)<<4) & 0xf0;
*(start+3) = 0;
return 0;
}
//++++++++++++++++++++++++++++++++++++++++++++++++
//create TPJOIN option: SYN
// top points to the beginning of the TCP options
// len provides the present length of options already contained
// If header to long, returns -1 without doing anything, otherwise 0
// We currently disregard from security material
//++++++++++++++++++++++++++++++++++++++++++++++++
int create_MPjoin_syn(unsigned char *top, uint16_t *plen, uint32_t token,
uint32_t rand_nmb, unsigned char addr_id, unsigned char backup) {
uint16_t new_len = 12;
if((*plen) + new_len > 40) {
snprintf(msg_buf,MAX_MSG_LENGTH, "Error:create_MPjoin_syn: too long");
add_msg(msg_buf);
return -1;
}
unsigned char *start = top + (*plen);
(*plen) += new_len;
if(backup > 1) backup = 1;
*(start) = MPTCP_KIND;
*(start+1) = 12;
*(start+2) = ( ( ((unsigned char) MPTCP_JOIN)<<4) + backup);
*(start+3) = addr_id;
*((uint32_t*) (start+4)) = token;
*((uint32_t*) (start+8)) = rand_nmb;
return 1;
}
//++++++++++++++++++++++++++++++++++++++++++++++++
//create TPJOIN option: SYNACK
// top points to the beginning of the TCP options
// len provides the present length of options already contained
// If header to long, returns -1 without doing anything, otherwise 0
// We currently disregard from security material
//++++++++++++++++++++++++++++++++++++++++++++++++
int create_MPjoin_synack(unsigned char *top, uint16_t *plen, uint32_t *mac,
uint32_t rand_nmb, unsigned char addr_id, unsigned char backup) {
uint16_t new_len = 16;
if((*plen) + new_len > 40) {
snprintf(msg_buf,MAX_MSG_LENGTH, "Error:create_MPjoin_synack: too long");
add_msg(msg_buf);
return -1;
}
unsigned char *start = top + (*plen);
(*plen) += new_len;
if(backup > 1) backup = 1;
*(start) = MPTCP_KIND;
*(start+1) = 16;
*(start+2) = ( ( ((unsigned char) MPTCP_JOIN)<<4) + backup);
*(start+3) = addr_id;
*((uint32_t*) (start+4)) = mac[0];
*((uint32_t*) (start+8)) = mac[1];
*((uint32_t*) (start+12)) = rand_nmb;
return 1;
}
//++++++++++++++++++++++++++++++++++++++++++++++++
//create TPJOIN option: ACK
// top points to the beginning of the TCP options
// len provides the present length of options already contained
// If header to long, returns -1 without doing anything, otherwise 0
// We currently disregard from security material
//++++++++++++++++++++++++++++++++++++++++++++++++
int create_MPjoin_ack(unsigned char *top, uint16_t *plen, uint32_t *mac) {
uint16_t new_len = 24;
if((*plen) + new_len > 40) {
snprintf(msg_buf,MAX_MSG_LENGTH, "Error:create_MPjoin_ack: too long");
add_msg(msg_buf);
return -1;
}
unsigned char *start = top + (*plen);
(*plen) += new_len;
*(start) = MPTCP_KIND;
*(start+1) = 24;
*(start+2) = ( ((unsigned char) MPTCP_JOIN)<<4) ;
*(start+3) = 0;
memcpy(start+4, (unsigned char*) mac, 20);
return 1;
}
int create_MPadd_addr(unsigned char *top, uint16_t *plen, unsigned char addr_id_loc, uint32_t ip_loc_n) {
uint16_t new_len = 8;
if((*plen) + new_len > 40) {
snprintf(msg_buf,MAX_MSG_LENGTH, "Error:create_MPadd_addr: too long");
add_msg(msg_buf);
return -1;
}
unsigned char *start = top + (*plen);
(*plen) += new_len;
*(start) = 30;
*(start+1) = new_len;
*(start+2) = 0x34u;
*(start+3) = addr_id_loc;
*((uint32_t*) (start+4)) = ip_loc_n;
return 1;
}
//++++++++++++++++++++++++++++++++++++++++++++++++
//create DSS option with DAN only: used only for side ACKs
//++++++++++++++++++++++++++++++++++++++++++++++++
int create_dan_MPdss_nondssopt(unsigned char *top, uint16_t *plen, uint32_t dan) {
uint16_t new_len = 8;
if((*plen) + new_len > 40) {
snprintf(msg_buf,MAX_MSG_LENGTH, "Error:create_dan_MPdss_nondssopt: too long");
add_msg(msg_buf);
return -1;
}
unsigned char *start = top + (*plen);
*plen += new_len;
*(start) = MPTCP_KIND;
*(start+1) = new_len;
*(start+2) = ( ((unsigned char) MPTCP_DSS)<<4) & 0xf0;
*(start+3) = 0;
*(start+3) += 1;
*((uint32_t*) (start+4)) = htonl(dan);
return 0;
}
//++++++++++++++++++++++++++++++++++++++++++++++++
//create DSS option with DAN only: used only for side ACKs
//++++++++++++++++++++++++++++++++++++++++++++++++
void create_dan_MPdss(unsigned char *mpbuf, uint16_t *mplen) {
*(mpbuf) = MPTCP_KIND;
*(mpbuf+1) = 8;
*(mpbuf+2) = ( ((unsigned char) MPTCP_DSS)<<4) & 0xf0;
*(mpbuf+3) = 0;
*(mpbuf+3) += (dssopt_out.Rflag & 0x01)<<5;
*(mpbuf+3) += (dssopt_out.Fflag & 0x01)<<4;
*(mpbuf+3) += dssopt_out.Aflag & 0x01;
*((uint32_t*) (mpbuf+4)) = htonl(dssopt_out.dan);
*mplen += 8;
return;
}
//++++++++++++++++++++++++++++++++++++++++++++++++
//create DSS option: uses dssopt_out as input
// mpbuf points to the beginning of the buffer for the TCP option
// len provides the present length of options already contained
// We currently disregard checksum
//++++++++++++++++++++++++++++++++++++++++++++++++
void create_complete_MPdss(unsigned char *mpbuf, uint32_t idsn_high, unsigned char *payload, uint16_t len_payload) {//, unsigned char *payload,uint16_t len_payload
unsigned char tpdss_len = (dssopt_out.Aflag)? 8:4;//4 bytes min, 8bytes if dan present
tpdss_len += (dssopt_out.Mflag)? 12:0;//add 8bytes more for dsn and ssn
packd.mptcp_opt_len += tpdss_len;
*(mpbuf) = MPTCP_KIND;
*(mpbuf+1) = tpdss_len;
*(mpbuf+2) = ( ((unsigned char) MPTCP_DSS)<<4) & 0xf0;
*(mpbuf+3) = 0;
*(mpbuf+3) += (dssopt_out.Rflag & 0x01)<<5;
*(mpbuf+3) += (dssopt_out.Fflag & 0x01)<<4;
*(mpbuf+3) += (dssopt_out.mflag & 0x01)<<3;
*(mpbuf+3) += (dssopt_out.Mflag & 0x01)<<2;
*(mpbuf+3) += (dssopt_out.aflag & 0x01)<<1;
*(mpbuf+3) += dssopt_out.Aflag & 0x01;
unsigned char it=0;
if(dssopt_out.Aflag) {
*((uint32_t*) (mpbuf+4)) = htonl(dssopt_out.dan);
it+=4;
}
if(dssopt_out.Mflag) {
*((uint32_t*) (mpbuf+4+it)) = htonl(dssopt_out.dsn);
*((uint32_t*) (mpbuf+8+it)) = htonl(dssopt_out.ssn);
*((uint16_t*) (mpbuf+12+it)) = htons(dssopt_out.range);
*((uint16_t*) (mpbuf+14+it)) = 0;
*((uint16_t*) (mpbuf+14+it)) = mpdsm_checksum(mpbuf+4+it,idsn_high,payload,len_payload);
}
}
int create_complete_MPdss_nondssopt(unsigned char *top, uint16_t *plen,
uint32_t data_ack_h, uint32_t data_seq_next_h, uint32_t sub_seq_next_h, uint32_t idsn_high, unsigned char *payload,uint16_t len_payload) {
unsigned char new_len = 20;
if((*plen) + new_len > 40) {
snprintf(msg_buf,MAX_MSG_LENGTH, "Error:create_complete_MPdss_nondssopt: too long");
add_msg(msg_buf);
return -1;
}
unsigned char* start = top + (*plen);
*plen += new_len;
*(start) = 30;
*(start+1) = new_len;
*(start+2) = ( ((unsigned char) MPTCP_DSS)<<4) & 0xf0;
*(start+3) = 0x05;
*((uint32_t*) (start+4)) = htonl(data_ack_h);
*((uint32_t*) (start+8)) = htonl(data_seq_next_h);
*((uint32_t*) (start+12)) = htonl(sub_seq_next_h);
*((uint16_t*) (start+16)) = htons(len_payload);
*((uint16_t*) (start+18)) = 0;
*((uint16_t*) (start+18)) = mpdsm_checksum(start+8,idsn_high,payload,len_payload);
return 0;
}
//++++++++++++++++++++++++++++++++++++++++++++++++
//create TPprio option:
//++++++++++++++++++++++++++++++++++++++++++++++++
void create_MPprio4(unsigned char *mpbuf, unsigned char addr_id_loc, unsigned char backup) {
*(mpbuf) = MPTCP_KIND;
*(mpbuf+1) = 4;
*(mpbuf+2) = ( ((unsigned char) MPTCP_PRIO)<<4) + backup;
*(mpbuf+3) = addr_id_loc;
}
//++++++++++++++++++++++++++++++++++++++++++++++++
//create TPprio option:
//++++++++++++++++++++++++++++++++++++++++++++++++
void create_MPprio3(unsigned char *mpbuf, unsigned char backup) {
*(mpbuf) = MPTCP_KIND;
*(mpbuf+1) = 3;
*(mpbuf+2) = ( ((unsigned char) MPTCP_PRIO)<<4) + backup;
}
//++++++++++++++++++++++++++++++++++++++++++++++++
//create TPremove_addr_option:
//++++++++++++++++++++++++++++++++++++++++++++++++
void create_MPremove_addr(unsigned char *mpbuf, unsigned char addr_id_loc) {
*(mpbuf) = MPTCP_KIND;
*(mpbuf+1) = 4;
*(mpbuf+2) = ( ((unsigned char) MPTCP_REMOVE_ADDR)<<4);
*(mpbuf+3) = addr_id_loc;
}
//++++++++++++++++++++++++++++++++++++++++++++++++
//create TP_RESET option
// mpbuf points to packd.tptop_opt_buf.
//++++++++++++++++++++++++++++++++++++++++++++++++
int create_MPreset(unsigned char *mpbuf, uint32_t *key_rem) {
unsigned char tpcap_len = 12;
if(packd.mptcp_opt_len + tpcap_len > 40) return 0;
packd.mptcp_opt_len += tpcap_len;
*(mpbuf) = MPTCP_KIND;
*(mpbuf+1) = tpcap_len;
*(mpbuf+2) = ( ((unsigned char) MPTCP_RST)<<4) & 0xf0;
*(mpbuf+3) = 1;//no checksum
*((uint32_t*) (mpbuf+4)) = key_rem[0];
*((uint32_t*) (mpbuf+8)) = key_rem[1];
return 1;
}
//++++++++++++++++++++++++++++++++++++++++++++++++
//create new packet:
// Copies IPv4 header, tcp-core header + payload from packd.buf to packd.new_buf
// Replaces tcp_opt with tcp_opt_buf
// Sets packd.ipv and packd.tcph to new_buf
// Checksums are fixed in filter05 based on verdict!
//++++++++++++++++++++++++++++++++++++++++++++++++
void create_new_packet(unsigned char *const tcp_opt_buf, uint16_t len){
//add ipv4 header, core tcp header
memmove(packd.new_buf, packd.buf, packd.ip4len + 20);
//add new TCP options
memmove(packd.new_buf + packd.ip4len + 20, tcp_opt_buf, len);
//add old payload
memmove(packd.new_buf + packd.ip4len + 20 + len, packd.buf + packd.pos_pay, packd.paylen);
//update packd
packd.tcplen = 20 + len;
packd.pos_pay = packd.pos_thead + packd.tcplen;
packd.totlen = packd.ip4len + packd.tcplen + packd.paylen;
packd.ip4h = (struct ipheader*) (packd.new_buf+packd.pos_i4head);
packd.tcph = (struct tcpheader*) (packd.new_buf+packd.pos_i4head+packd.ip4len);
//add new tcp header length into packet
packd.tcph->th_off = packd.tcplen>>2;
//fix_checksums(packd.new_buf, packd.ip4len, packd.totlen);
packd.tcp_opt_len = len;
}
//++++++++++++++++++++++++++++++++++++++++++++++++
//find TP option: evaluates TP option array for some subkind
//++++++++++++++++++++++++++++++++++++++++++++++++
inline int find_MPsubkind(struct mptcp_option * const mptopt, size_t nb_options, const unsigned char subkind) {
unsigned i=0;
if(nb_options == 0)
return -1;
while(i<nb_options && (((mptopt[i].byte3)>>4) & 0x0f) != subkind ) {
i++;
}
return (i==nb_options)? -1 : (int)i;
}
//++++++++++++++++++++++++++++++++++++++++++++++++
//analyzes TPTCP cap option
// Finds TPcap in in mptcp_option array
// Extracts IDSNloc and IDSNrem
// returns 0 if header not found or too short
//++++++++++++++++++++++++++++++++++++++++++++++++
int analyze_MPcap(struct mptcp_option * const mptopt, size_t const nb_topt, uint32_t *key_loc, uint32_t *key_rem) {
int it = find_MPsubkind(mptopt, nb_topt, MPTCP_CAP);
if(it < 0)
return 0;
if(mptopt[it].len != 12 && mptopt[it].len != 20 )
return 0;
key_rem[0] = *(uint32_t *) (mptopt[it].data);
key_rem[1] = *(uint32_t *) (mptopt[it].data + 4);
//both IDSNrem present
if(mptopt[it].len == 20){
key_loc[0] = *(uint32_t *) (mptopt[it].data +8);
key_loc[1] = *(uint32_t *) (mptopt[it].data +12);
}
//WTF ?
//else key_loc == NULL;
return 1;
}
//++++++++++++++++++++++++++++++++++++++++++++++++
//analyzes TPTCP join_syn option
//++++++++++++++++++++++++++++++++++++++++++++++++
int analyze_MPjoin_syn(struct mptcp_option * const mptopt, size_t const nb_topt,
uint32_t *token, uint32_t *rand_nmb, unsigned char *address_id, unsigned char *backup) {
int it = find_MPsubkind(mptopt, nb_topt, MPTCP_JOIN);
if(it < 0)
return 0;
if(mptopt[it].len != 12)
return 0;
//get token and find session
*address_id = (mptopt[it].byte4);
*backup = (mptopt[it].byte4 & 0x01);
*token = (*(uint32_t *) (mptopt[it].data));
*rand_nmb = * (uint32_t *) (mptopt[it].data+4);
return 1;
}
//++++++++++++++++++++++++++++++++++++++++++++++++
//analyzes TPTCP join synack option
//++++++++++++++++++++++++++++++++++++++++++++++++
int analyze_MPjoin_synack(struct mptcp_option * const mptopt, size_t const nb_topt,
uint32_t *mac, uint32_t *rand_nmb, unsigned char *address_id, unsigned char *backup) {
int it = find_MPsubkind(mptopt, nb_topt, MPTCP_JOIN);
if(it < 0){
log_error("analyze_MPjoin_synack: no mpsubkind found");
return 0;
}
if(mptopt[it].len != 16){
log_error("analyze_MPjoin_synack: mpoption len incorrect");
return 0;
}
//get token and find session
*backup = (mptopt[it].byte4 & 0x01);
*address_id = (mptopt[it].byte4);
*mac = *( (uint32_t *) (mptopt[it].data)) ;
*(mac + 1) = *( (uint32_t *) (mptopt[it].data + 4));
*rand_nmb = * (uint32_t *) (mptopt[it].data + 8);
return 1;
}
//++++++++++++++++++++++++++++++++++++++++++++++++
//analyzes TPTCP join ack option
//++++++++++++++++++++++++++++++++++++++++++++++++
int analyze_MPjoin_ack(struct mptcp_option * const mptopt, size_t const nb_topt, uint32_t *mac) {
int it = find_MPsubkind(mptopt, nb_topt, MPTCP_JOIN);
if(it < 0)
return 0;
if(mptopt[it].len != 24)
return 0;
//get token and find session
int i;
for(i=0;i<5;i++) {
*(mac + i) = *( (uint32_t *) (mptopt[it].data + 4*i));
}
return 1;
}
//++++++++++++++++++++++++++++++++++++++++++++++++
//analyze TPTCP dss option (we already know that this is a dss option)
// writes on dssopt
//++++++++++++++++++++++++++++++++++++++++++++++++
int analyze_MPdss(struct mptcp_option *const tptop, size_t const nb_topt) {
int i1 = find_MPsubkind(mptopt, nb_topt, MPTCP_DSS);
if(i1 < 0) {
dssopt_in.present = 0;
return 0;
}
dssopt_in.present = 1;
dssopt_in.Rflag = (tptop[i1].byte4 & 0x20)>>5;
dssopt_in.Fflag = (tptop[i1].byte4 & 0x10)>>4;
dssopt_in.mflag = (tptop[i1].byte4 & 0x08)>>3;
dssopt_in.Mflag = (tptop[i1].byte4 & 0x04)>>2;
dssopt_in.aflag = (tptop[i1].byte4 & 0x02)>>1;
dssopt_in.Aflag = tptop[i1].byte4 & 0x01;
//we assume that aflag and mflag are always 0
size_t i2 = 0;
if(dssopt_in.Aflag) {
if(tptop[i1].len<8) return 0;
dssopt_in.dan = ntohl( *((uint32_t*) tptop[i1].data));
i2 = 4;
}
if(dssopt_in.Mflag) {
if(tptop[i1].len<12+i2) return 0;
dssopt_in.dsn = ntohl( *((uint32_t*) (tptop[i1].data+i2)));
dssopt_in.ssn = ntohl( *((uint32_t*) (tptop[i1].data+i2+4)));
dssopt_in.range = ntohs( *((uint16_t*) (tptop[i1].data+i2+8)));
}
return 1;
}
//++++++++++++++++++++++++++++++++++++++++++++++++
//analyze TPprio option:
// Returns 0 if subkind not found, 1 if 3-bytes (no addr_id_rem), 2 if 4-bytes (incl addr_id_rem)
//++++++++++++++++++++++++++++++++++++++++++++++++
int analyze_MPprio(struct mptcp_option *const tptop, size_t const nb_topt,
unsigned char *addr_id_rem, unsigned char *backup) {
int i1 = find_MPsubkind(mptopt, nb_topt, MPTCP_PRIO);
if(i1 < 0)
return 0;
*backup = tptop[i1].byte3 & 0x0f;
*addr_id_rem = 0;
if(tptop[i1].len == 3) {
return 1;
} else {
*addr_id_rem = tptop[i1].byte4;
return 2;
}
}
//++++++++++++++++++++++++++++++++++++++++++++++++
//analyze TPprio option:
// If header to long, returns -1 without doing anything, otherwise 0
//++++++++++++++++++++++++++++++++++++++++++++++++
int analyze_MPremove_addr(struct mptcp_option *const tptop, size_t const nb_topt, unsigned char *addr_id_rem) {
int i1 = find_MPsubkind(mptopt, nb_topt, MPTCP_REMOVE_ADDR);
if(i1 < 0)
return 0;
*addr_id_rem = tptop[i1].byte4;
return 1;
}
//++++++++++++++++++++++++++++++++++++++++++++++++
//analyzes TPTCP reset option
// Finds TPcap in in mptcp_option array
// Extracts IDSNloc and IDSNrem
// returns 0 if header not found or too short
//++++++++++++++++++++++++++++++++++++++++++++++++
int analyze_MPreset(struct mptcp_option * const mptopt, size_t const nb_topt, uint32_t *key_loc) {
int it = find_MPsubkind(mptopt, nb_topt, MPTCP_RST);
if(it < 0)
return 0;
if(mptopt[it].len != 12)
return 0;
key_loc[0] = *(uint32_t *) (mptopt[it].data);
key_loc[1] = *(uint32_t *) (mptopt[it].data + 4);
return 1;
}
//++++++++++++++++++++++++++++++++++++++++++++++++
//PACKMAN: prepare_traffic_ack()
// Prepares ack for candidate subflow in parallel to traffic packet on active subflow (thruway)
// Packet only serves to satisfy subflow SSN/SAN consistency.
// It does carries a DAN (4B) and the tcp options contained on the thruway input packet
//++++++++++++++++++++++++++++++++++++++++++++++++
int prepare_top_side_ack() {
//create tcp_opt_buf_ack for side acks
//copy tcp_opt_buf to tcp_opt_buf_ack
packd.tcp_opt_len_ack = packd.tcp_opt_len;//copy over the tcp_opt_len value to avoid that it's updated
memcpy(packd.tcp_opt_buf_ack, packd.tcp_opt_buf, packd.tcp_opt_len);
//create dan
packd.mptcp_opt_len_ack = 0;
create_dan_MPdss(packd.mptcp_opt_buf_ack, &packd.mptcp_opt_len_ack);