/* Insertion sort of the packet in the buffer using its seqnum */
void insert_descending_order(struct tcp_buf *tcp_buffer, struct ofpbuf *pkt){
int i, index;
uint32_t seq_buf, seq_new;
index = 0;
if(tcp_buffer->inserted_items == 0){
tcp_buffer->buffer[0] = pkt;
}
else{
seq_buf = get_tcp_seq(tcp_buffer->buffer[index]);
seq_new = get_tcp_seq(pkt);
// Find the correct position for the item
while((seq_new <= seq_buf) && (index<tcp_buffer->inserted_items)){
index++;
if(seq_new == seq_buf){
tcp_buffer->expected_seqnum = get_next_seqnum(tcp_buffer, seq_new, pkt, false);
}
if(tcp_buffer->buffer[index]){
seq_buf = get_tcp_seq(tcp_buffer->buffer[index]);
}
}
// Shift the elements to the right
for(i=tcp_buffer->inserted_items;i>index;i--){
tcp_buffer->buffer[i] = tcp_buffer->buffer[i-1];
}
tcp_buffer->buffer[index] = pkt;
}
tcp_buffer->inserted_items++;
tcp_buffer->consecutive_buffering_events++;
}
void Packet::print()
{
uint32_t tsval, tsecr;
char sip_str[INET_ADDRSTRLEN];
char dip_str[INET_ADDRSTRLEN];
inet_ntop(AF_INET, &ip_hdr->ip_src.s_addr, sip_str, INET_ADDRSTRLEN);
inet_ntop(AF_INET, &ip_hdr->ip_dst.s_addr, dip_str, INET_ADDRSTRLEN);
get_tcp_ts(&tsval,&tsecr);
switch(get_ip_protocol())
{
case IPPROTO_TCP:
std::cout << "TCP packet: "
<< "[" << get_ts().tv_sec << "." << std::setw(9) << std::setfill('0') << get_ts().tv_nsec << "] ["
<< sip_str << ":" << get_tcp_sport() << "->"
<< dip_str << ":" << get_tcp_dport() << "] "
<< "[S:" << get_tcp_seq() << "] "
<< "[A:" << get_tcp_ack() << "] "
<< "[L:" << get_tcp_payload_len() << "] "
<< "[M:" << get_tcp_mss() << "] "
<< "[TV:" << tsval << "] "
<< "[TE:" << tsecr << "]"
<< std::endl << std::flush;
break;
case IPPROTO_ICMP:
std::cout << "ICMP packet: ["
<< sip_str << "->"
<< dip_str << "] "
<< "[TTL:" << get_ip_ttl() << "]"
<< std::endl << std::flush;
break;
default:
std::cout << "Unknown packet!" << std::endl << std::flush;
break;
}
}
int get_packet_list(struct ofpbuf *out_packets[], struct ofpbuf * packet, uint32_t flow_id, uint32_t in_port){
struct tcp_buf * tcp_buf;
uint8_t tcp_flags;
struct tcp_header *tcp;
uint32_t seq;
int i, out_packets_count;
uint32_t seq_work;
struct ofpbuf * buf_pkt;
int removed_items;
// Getting the buffer for the flow, or creating a new one if
// not existing
tcp_buf = get_tcp_buf(flow_id);
tcp = ofpbuf_l4(packet);
tcp_flags = TCP_FLAGS(tcp->tcp_ctl);
seq = get_tcp_seq(packet);
out_packets_count = 0;
if (tcp_flags & TCP_SYN){
tcp_buf->expected_seqnum = seq+1;
VLOG_INFO("[SYN packet] sequence: %" PRIu32 " expected: %" PRIu32 " in_port: %"PRIu32 " size: %d",
seq, tcp_buf->expected_seqnum, in_port, tcp_buf->inserted_items);
out_packets[out_packets_count] = packet;
out_packets_count++;
}
else if(tcp_buf->fin_state){
delete_tcp_buf(tcp_buf);
out_packets[out_packets_count] = packet;
out_packets_count++;
}
// Retransmission or packets which come without a SYN or after a FIN
// Just send out
else if(tcp_buf->expected_seqnum == -1){
out_packets[out_packets_count] = packet;
out_packets_count++;
}
// Sending out and checking if the the gap in the reordering buffer has been filled
else if(seq <= tcp_buf->expected_seqnum){
VLOG_INFO("[sending in order packet] seq: %"PRIu32 " expected: %" PRIu32 " in_port: %"PRIu32 " size: %d",
seq, tcp_buf->expected_seqnum, in_port, tcp_buf->inserted_items);
out_packets[out_packets_count] = packet;
out_packets_count++;
tcp_buf->consecutive_buffering_events = 0;
// Increasing sequence only if it matches
if(seq == tcp_buf->expected_seqnum){
tcp_buf->expected_seqnum = get_next_seqnum(tcp_buf, tcp_buf->expected_seqnum, packet, false);
}
// Check if there are packets waiting to be sent
removed_items = 0;
for(i=tcp_buf->inserted_items-1;i>= 0;i--){
seq_work = get_tcp_seq(tcp_buf->buffer[i]);
if(seq_work <= tcp_buf->expected_seqnum){
VLOG_INFO("[sending out from buffer] sequence: %" PRIu32 " expected: %" PRIu32 " size: %d",
seq_work, tcp_buf->expected_seqnum, tcp_buf->inserted_items - removed_items);
removed_items++;
out_packets[out_packets_count] = tcp_buf->buffer[i];
out_packets_count++;
if(seq_work == tcp_buf->expected_seqnum){
tcp_buf->expected_seqnum = get_next_seqnum(tcp_buf, tcp_buf->expected_seqnum, tcp_buf->buffer[i], false);
}
}
}
tcp_buf->inserted_items = tcp_buf->inserted_items - removed_items;
}
// Buffer not full yet, buffering the packet
else if(tcp_buf->inserted_items<TCP_BUF_SIZE && tcp_buf->consecutive_buffering_events < CONSECUTIVE_BUFFERING_TREESHOLD){
VLOG_INFO("[buffering] sequence: %"PRIu32 " expected: %" PRIu32 " in_port: %"PRIu32 " size: %d",
seq, tcp_buf->expected_seqnum, in_port, tcp_buf->inserted_items);
buf_pkt = ofpbuf_clone(packet);
insert_descending_order(tcp_buf, buf_pkt);
}
// Buffer full or loss event detecte
else{
VLOG_WARN("!! -- Empty Buffer Event -- !!");
if(tcp_buf->consecutive_buffering_events >= CONSECUTIVE_BUFFERING_TREESHOLD)
syslog(LOG_INFO, "!! -- Because of an apparent loss -- !!");
seq_work = get_tcp_seq(tcp_buf->buffer[tcp_buf->inserted_items-1]);
// If incoming packet has the smallest sequence
if(seq<seq_work){
VLOG_INFO("[resetting buffer] sequence: %" PRIu32, seq);
out_packets[out_packets_count] = packet;
out_packets_count++;
}
// If a packet in the buffer has the smallest sequence
else{
VLOG_INFO("[resetting] sequence: %" PRIu32, get_tcp_seq(tcp_buf->buffer[tcp_buf->inserted_items-1]));
out_packets[out_packets_count] = tcp_buf->buffer[tcp_buf->inserted_items-1];
out_packets_count++;
tcp_buf->inserted_items--;
buf_pkt = ofpbuf_clone(packet);
insert_descending_order(tcp_buf, buf_pkt);
}
// Completely empty the buffer
for(i=tcp_buf->inserted_items-1;i>= 0;i--){
seq_work = get_tcp_seq(tcp_buf->buffer[i]);
VLOG_INFO("resetting %" PRIu32, seq_work);
get_next_seqnum(tcp_buf, seq_work, tcp_buf->buffer[i], false);
out_packets[out_packets_count] = tcp_buf->buffer[i];
out_packets_count++;
// Adjusting seqnum
if(i==0){
tcp_buf->expected_seqnum = get_next_seqnum(tcp_buf, seq_work, tcp_buf->buffer[i], false);
}
}
tcp_buf->inserted_items=0;
if(tcp_buf->consecutive_buffering_events >= CONSECUTIVE_BUFFERING_TREESHOLD){
tcp_buf->expected_seqnum = get_next_seqnum(tcp_buf, tcp_buf->expected_seqnum, packet, true);
}
}
return out_packets_count;
}
