+// process Multilink PPP packet received
+void processmpin(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
+{
+ bundleidt b = session[s].bundle;
+ bundlet * this_bundle = &bundle[b];
+ uint32_t maskSeq, max_seq;
+ int frag_offset;
+ uint16_t frag_index, frag_index_next, frag_index_prev;
+ fragmentationt *this_fragmentation = &frag[b];
+ uint8_t begin_frame = (*p & MP_BEGIN);
+ uint8_t end_frame = (*p & MP_END);
+ uint32_t seq_num, seq_num_next, seq_num_prev;
+ uint32_t i;
+ uint8_t flags = *p;
+ uint16_t begin_index, end_index;
+
+ // Perform length checking
+ if(l > MAXFRAGLEN)
+ {
+ LOG(2, s, t, "MPPP: discarding fragment larger than MAXFRAGLEN\n");
+ return;
+ }
+
+ if(!b)
+ {
+ LOG(2, s, t, "MPPP: Invalid bundle id: 0\n");
+ return;
+ }
+ // FIXME !! session[s].mssf means that the receiver wants to receive frames in mssf not means the receiver will send frames in mssf
+ /* if(session[s].mssf)
+ {
+ // Get 12 bit for seq number
+ seq_num = ntohs((*(uint16_t *) p) & 0xFF0F);
+ p += 2;
+ l -= 2;
+ // After this point the pointer should be advanced 2 bytes
+ LOG(3, s, t, "MPPP: 12 bits, sequence number: %d\n",seq_num);
+ }
+ else */
+ {
+ // Get 24 bit for seq number
+ seq_num = ntohl((*(uint32_t *) p) & 0xFFFFFF00);
+ p += 4;
+ l -= 4;
+ // After this point the pointer should be advanced 4 bytes
+ LOG(4, s, t, "MPPP: 24 bits sequence number:%d\n",seq_num);
+ }
+
+ max_seq = this_bundle->max_seq;
+ maskSeq = max_seq - 1;
+
+ /*
+ * Expand sequence number to 32 bits, making it as close
+ * as possible to this_fragmentation->M.
+ */
+ seq_num |= this_fragmentation->M & ~maskSeq;
+ if ((int)(this_fragmentation->M - seq_num) > (int)(maskSeq >> 1))
+ {
+ seq_num += maskSeq + 1;
+ }
+ else if ((int)(seq_num - this_fragmentation->M) > (int)(maskSeq >> 1))
+ {
+ seq_num -= maskSeq + 1; /* should never happen */
+ }
+
+ // calculate this fragment's offset from the begin seq in the bundle
+ frag_offset = (int) (seq_num - this_fragmentation->start_seq);
+
+ sess_local[s].last_seq = seq_num;
+
+ // calculate the jitter average
+ uint32_t ljitter = time_now_ms - sess_local[s].prev_time;
+ if (ljitter > 0)
+ {
+ sess_local[s].jitteravg = (sess_local[s].jitteravg + ljitter)>>1;
+ sess_local[s].prev_time = time_now_ms;
+ }
+
+ uint32_t Mmin;
+
+ if (seq_num < this_fragmentation->M)
+ {
+ Mmin = seq_num;
+ this_fragmentation->M = seq_num;
+ }
+ else
+ {
+ Mmin = sess_local[(this_bundle->members[0])].last_seq;
+ for (i = 1; i < this_bundle->num_of_links; i++)
+ {
+ uint32_t s_seq = sess_local[(this_bundle->members[i])].last_seq;
+ if (s_seq < Mmin)
+ Mmin = s_seq;
+ }
+ this_fragmentation->M = Mmin;
+ }
+
+ // calculate M offset of the M seq in the bundle
+ int M_offset = (int) (Mmin - this_fragmentation->start_seq);
+
+ if (M_offset >= MAXFRAGNUM)
+ {
+ // There have a long break of the link !!!!!!!!
+ // M_offset is bigger that the fragmentation buffer size
+ LOG(3, s, t, "MPPP: M_offset out of range, min:%d, begin_seq:%d, jitteravg:%d\n", Mmin, this_fragmentation->start_seq, sess_local[s].jitteravg);
+
+ // Calculate the new start index, the previous frag are lost
+ begin_index = (M_offset + this_fragmentation->start_index) & MAXFRAGNUM_MASK;
+
+ // Set new Start sequence
+ this_fragmentation->start_index = begin_index;
+ this_fragmentation->start_seq = Mmin;
+ M_offset = 0;
+ // recalculate the fragment offset from the new begin seq in the bundle
+ frag_offset = (int) (seq_num - Mmin);
+ }
+
+ // discard this fragment if the packet comes before the start sequence
+ if (frag_offset < 0)
+ {
+ // this packet comes before the next
+ LOG(3, s, t, "MPPP: packet comes before the next, seq:%d, begin_seq:%d, size frag:%d\n", seq_num, this_fragmentation->start_seq, l);
+ return;
+ }
+
+ // discard if frag_offset is bigger that the fragmentation buffer size
+ if (frag_offset >= MAXFRAGNUM)
+ {
+ // frag_offset is bigger that the fragmentation buffer size
+ LOG(3, s, t, "MPPP: Index out of range, seq:%d, begin_seq:%d, jitteravg:%d\n", seq_num, this_fragmentation->start_seq, sess_local[s].jitteravg);
+ return;
+ }
+
+ //caculate received fragment's index in the fragment array
+ frag_index = (frag_offset + this_fragmentation->start_index) & MAXFRAGNUM_MASK;
+
+ // insert the frame in it's place
+ fragmentt *this_frag = &this_fragmentation->fragment[frag_index];
+
+ if (this_frag->length > 0)
+ // This fragment is lost, It was around the buffer and it was never completed the packet.
+ LOG(3, this_frag->sid, this_frag->tid, "MPPP: (INSERT) seq_num:%d frag_index:%d flags:%d jitteravg:%d is LOST\n",
+ this_frag->seq, frag_index, this_frag->flags, this_frag->jitteravg);
+
+ this_frag->length = l;
+ this_frag->sid = s;
+ this_frag->tid = t;
+ this_frag->flags = flags;
+ this_frag->seq = seq_num;
+ this_frag->jitteravg = sess_local[s].jitteravg;
+ memcpy(this_frag->data, p, l);
+
+ LOG(4, s, t, "MPPP: seq_num:%d frag_index:%d INSERTED flags: %02X\n", seq_num, frag_index, flags);
+
+ //next frag index
+ frag_index_next = (frag_index + 1) & MAXFRAGNUM_MASK;
+ //previous frag index
+ frag_index_prev = (frag_index - 1) & MAXFRAGNUM_MASK;
+ // next seq
+ seq_num_next = seq_num + 1;
+ // previous seq
+ seq_num_prev = seq_num - 1;
+
+ // Clean the buffer and log the lost fragments
+ if ((frag_index_next != this_fragmentation->start_index) && this_fragmentation->fragment[frag_index_next].length)
+ {
+ // check if the next frag is a lost fragment
+ if (this_fragmentation->fragment[frag_index_next].seq != seq_num_next)
+ {
+ // This fragment is lost, It was around the buffer and it was never completed the packet.
+ LOG(3, this_fragmentation->fragment[frag_index_next].sid, this_fragmentation->fragment[frag_index_next].tid,
+ "MPPP: (NEXT) seq_num:%d frag_index:%d flags:%d jitteravg:%d is LOST\n",
+ this_fragmentation->fragment[frag_index_next].seq, frag_index_next,
+ this_fragmentation->fragment[frag_index_next].flags, this_fragmentation->fragment[frag_index_next].jitteravg);
+ // this frag is lost
+ this_fragmentation->fragment[frag_index_next].length = 0;
+ this_fragmentation->fragment[frag_index_next].flags = 0;
+
+ if (begin_frame && (!end_frame)) return; // assembling frame failed
+ }
+ }
+
+ // Clean the buffer and log the lost fragments
+ if ((frag_index != this_fragmentation->start_index) && this_fragmentation->fragment[frag_index_prev].length)
+ {
+ // check if the next frag is a lost fragment
+ if (this_fragmentation->fragment[frag_index_prev].seq != seq_num_prev)
+ {
+ // This fragment is lost, It was around the buffer and it was never completed the packet.
+ LOG(3, this_fragmentation->fragment[frag_index_prev].sid, this_fragmentation->fragment[frag_index_prev].tid,
+ "MPPP: (PREV) seq_num:%d frag_index:%d flags:%d jitteravg:%d is LOST\n",
+ this_fragmentation->fragment[frag_index_prev].seq, frag_index_prev,
+ this_fragmentation->fragment[frag_index_prev].flags, this_fragmentation->fragment[frag_index_prev].jitteravg);
+
+ this_fragmentation->fragment[frag_index_prev].length = 0;
+ this_fragmentation->fragment[frag_index_prev].flags = 0;
+
+ if (end_frame && (!begin_frame)) return; // assembling frame failed
+ }
+ }
+
+find_frame:
+ begin_index = this_fragmentation->start_index;
+ uint32_t b_seq = this_fragmentation->start_seq;
+ // Try to find a Begin sequence from the start_seq sequence to M sequence
+ while (b_seq < Mmin)
+ {
+ if (this_fragmentation->fragment[begin_index].length)
+ {
+ if (b_seq == this_fragmentation->fragment[begin_index].seq)
+ {
+ if (this_fragmentation->fragment[begin_index].flags & MP_BEGIN)
+ {
+ int isfoundE = 0;
+ // Adjust the new start sequence and start index
+ this_fragmentation->start_index = begin_index;
+ this_fragmentation->start_seq = b_seq;
+ // Begin Sequence found, now try to found the End Sequence to complete the frame
+ end_index = begin_index;
+ while (b_seq < Mmin)
+ {
+ if (this_fragmentation->fragment[end_index].length)
+ {
+ if (b_seq == this_fragmentation->fragment[end_index].seq)
+ {
+ if (this_fragmentation->fragment[end_index].flags & MP_END)
+ {
+ // The End sequence was found and the frame is complete
+ isfoundE = 1;
+ break;
+ }
+ }
+ else
+ {
+ // This fragment is lost, it was never completed the packet.
+ LOG(3, this_fragmentation->fragment[end_index].sid, this_fragmentation->fragment[end_index].tid,
+ "MPPP: (FIND END) seq_num:%d frag_index:%d flags:%d jitteravg:%d is LOST\n",
+ this_fragmentation->fragment[end_index].seq, begin_index,
+ this_fragmentation->fragment[end_index].flags, this_fragmentation->fragment[end_index].jitteravg);
+ // this frag is lost
+ this_fragmentation->fragment[end_index].length = 0;
+ this_fragmentation->fragment[end_index].flags = 0;
+ // This frame is not complete find the next Begin
+ break;
+ }
+ }
+ else
+ {
+ // This frame is not complete find the next Begin if exist
+ break;
+ }
+ end_index = (end_index +1) & MAXFRAGNUM_MASK;
+ b_seq++;
+ }
+
+ if (isfoundE)
+ // The End sequence was found and the frame is complete
+ break;
+ else
+ // find the next Begin
+ begin_index = end_index;
+ }
+ }
+ else
+ {
+ // This fragment is lost, it was never completed the packet.
+ LOG(3, this_fragmentation->fragment[begin_index].sid, this_fragmentation->fragment[begin_index].tid,
+ "MPPP: (FIND BEGIN) seq_num:%d frag_index:%d flags:%d jitteravg:%d is LOST\n",
+ this_fragmentation->fragment[begin_index].seq, begin_index,
+ this_fragmentation->fragment[begin_index].flags, this_fragmentation->fragment[begin_index].jitteravg);
+ // this frag is lost
+ this_fragmentation->fragment[begin_index].length = 0;
+ this_fragmentation->fragment[begin_index].flags = 0;
+ }
+ }
+ begin_index = (begin_index +1) & MAXFRAGNUM_MASK;
+ b_seq++;
+ }
+
+assembling_frame:
+ // try to assemble the frame that has the received fragment as a member
+ // get the beginning of this frame
+ begin_index = end_index = this_fragmentation->start_index;
+ if (this_fragmentation->fragment[begin_index].length)
+ {
+ if (!(this_fragmentation->fragment[begin_index].flags & MP_BEGIN))
+ {
+ // should occur only after an "M_Offset out of range"
+ // The start sequence must be a begin sequence
+ this_fragmentation->start_index = (begin_index +1) & MAXFRAGNUM_MASK;
+ this_fragmentation->start_seq++;
+ return; // assembling frame failed
+ }
+ }
+ else
+ return; // assembling frame failed
+
+ // get the end of his frame
+ while (this_fragmentation->fragment[end_index].length)
+ {
+ if (this_fragmentation->fragment[end_index].flags & MP_END)
+ break;
+
+ end_index = (end_index +1) & MAXFRAGNUM_MASK;
+
+ if (end_index == this_fragmentation->start_index)
+ return; // assembling frame failed
+ }
+
+ // return if a lost fragment is found
+ if (!(this_fragmentation->fragment[end_index].length))
+ return; // assembling frame failed
+
+ // assemble the packet
+ //assemble frame, process it, reset fragmentation
+ uint16_t cur_len = 4; // This is set to 4 to leave 4 bytes for function processipin
+
+ LOG(4, s, t, "MPPP: processing fragments from %d to %d\n", begin_index, end_index);
+ // Push to the receive buffer
+
+ for (i = begin_index;; i = (i + 1) & MAXFRAGNUM_MASK)
+ {
+ this_frag = &this_fragmentation->fragment[i];
+ if(cur_len + this_frag->length > MAXETHER)
+ {
+ LOG(2, s, t, "MPPP: discarding reassembled frames larger than MAXETHER\n");
+ break;
+ }
+
+ memcpy(this_fragmentation->reassembled_frame+cur_len, this_frag->data, this_frag->length);
+ LOG(5, s, t, "MPPP: processing frame at %d, with len %d\n", i, this_frag->length);
+
+ cur_len += this_frag->length;
+ if (i == end_index)
+ {
+ this_fragmentation->re_frame_len = cur_len;
+ this_fragmentation->re_frame_begin_index = begin_index;
+ this_fragmentation->re_frame_end_index = end_index;
+ // Process the resassembled frame
+ LOG(5, s, t, "MPPP: Process the reassembled frame, len=%d\n",cur_len);
+ processmpframe(s, t, this_fragmentation->reassembled_frame, this_fragmentation->re_frame_len, 1);
+ break;
+ }
+ }
+
+ // Set reassembled frame length to zero after processing it
+ this_fragmentation->re_frame_len = 0;
+ for (i = begin_index;; i = (i + 1) & MAXFRAGNUM_MASK)
+ {
+ this_fragmentation->fragment[i].length = 0; // Indicates that this fragment has been consumed
+ this_fragmentation->fragment[i].flags = 0;
+ if (i == end_index)
+ break;
+ }
+
+ // Set the new start_index and start_seq
+ this_fragmentation->start_index = (end_index + 1) & MAXFRAGNUM_MASK;
+ this_fragmentation->start_seq = this_fragmentation->fragment[end_index].seq + 1;
+ LOG(4, s, t, "MPPP after assembling: start index is = %d, start seq=%d\n", this_fragmentation->start_index, this_fragmentation->start_seq);
+
+ begin_index = this_fragmentation->start_index;
+ if ((this_fragmentation->fragment[begin_index].length) &&
+ (this_fragmentation->fragment[begin_index].seq != this_fragmentation->start_seq))
+ {
+ LOG(3, this_fragmentation->fragment[begin_index].sid, this_fragmentation->fragment[begin_index].tid,
+ "MPPP: (START) seq_num:%d frag_index:%d flags:%d jitteravg:%d is LOST\n",
+ this_fragmentation->fragment[begin_index].seq, begin_index,
+ this_fragmentation->fragment[begin_index].flags, this_fragmentation->fragment[begin_index].jitteravg);
+ this_fragmentation->fragment[begin_index].length = 0;
+ this_fragmentation->fragment[begin_index].flags = 0;
+ }
+
+ if (this_fragmentation->start_seq <= Mmin)
+ // It's possible to find other complete frame or lost frame.
+ goto find_frame;
+ else if ((this_fragmentation->fragment[begin_index].length) &&
+ (this_fragmentation->fragment[begin_index].flags & MP_BEGIN))
+ // may be that the next frame is completed
+ goto assembling_frame;
+
+ return;
+}
+
projects / l2tpns.git / blobdiff