+ if (session[s].ppp.phase != Network || session[s].ppp.ipcp != Opened)
+ return;
+
+ if (!session[s].bundle || bundle[session[s].bundle].num_of_links < 2) // FIXME:
+ {
+ // no spoof (do sessionbyip to handled statically routed subnets)
+ if (ip != session[s].ip && sessionbyip(htonl(ip)) != s)
+ {
+ LOG(4, s, t, "Dropping packet with spoofed IP %s\n", fmtaddr(htonl(ip), 0));
+ return;
+ }
+ }
+
+ // run access-list if any
+ if (session[s].filter_in && !ip_filter(p, l, session[s].filter_in - 1))
+ return;
+
+ // adjust MSS on SYN and SYN,ACK packets with options
+ if ((ntohs(*(uint16_t *) (p + 6)) & 0x1fff) == 0 && p[9] == IPPROTO_TCP) // first tcp fragment
+ {
+ int ihl = (p[0] & 0xf) * 4; // length of IP header
+ if (l >= ihl + 20 && (p[ihl + 13] & TCP_FLAG_SYN) && ((p[ihl + 12] >> 4) > 5))
+ adjust_tcp_mss(s, t, p, l, p + ihl);
+ }
+
+ // Add on the tun header
+ p -= 4;
+ *(uint32_t *) p = htonl(PKTIP);
+ l += 4;
+
+ if (session[s].tbf_in)
+ {
+ // Are we throttling this session?
+ if (config->cluster_iam_master)
+ tbf_queue_packet(session[s].tbf_in, p, l);
+ else
+ master_throttle_packet(session[s].tbf_in, p, l);
+ return;
+ }
+
+ // send to ethernet
+ if (tun_write(p, l) < 0)
+ {
+ STAT(tun_tx_errors);
+ LOG(0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
+ l, strerror(errno), tunfd, p);
+
+ return;
+ }
+
+ p += 4;
+ l -= 4;
+
+ if (session[s].snoop_ip && session[s].snoop_port)
+ {
+ // Snooping this session
+ snoop_send_packet(p, l, session[s].snoop_ip, session[s].snoop_port);
+ }
+
+ update_sessions_in_stat(s, l);
+
+ eth_tx += l;
+
+ STAT(tun_tx_packets);
+ INC_STAT(tun_tx_bytes, l);
+}
+
+// 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, start_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);
+ start_index = this_fragmentation->start_index;
+
+ sess_local[s].last_seq = seq_num;
+
+ uint32_t min;
+
+ if (seq_num < this_fragmentation->M)
+ {
+ min = seq_num;
+ this_fragmentation->M = seq_num;
+ }
+ else
+ {
+ min = 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 < min)
+ min = s_seq;
+ }
+ this_fragmentation->M = min;
+ }
+
+ if (min >= (this_fragmentation->start_seq + this_bundle->num_of_links))
+ {
+ // Find the new start sequence, the previous frag are lost
+ // calculate M offset of the M seq in the bundle
+ int M_offset = (int) (min - this_fragmentation->start_seq);
+ begin_index = (M_offset + this_fragmentation->start_index) & MAXFRAGNUM_MASK;
+
+ 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, size frag:%d\n", min, this_fragmentation->start_seq, l);
+
+ // Set new Start sequence
+ this_fragmentation->start_index = begin_index;
+ this_fragmentation->start_seq = min;
+ M_offset = 0;
+ // recalculate the fragment offset from the new begin seq in the bundle
+ frag_offset = (int) (seq_num - min);
+ }
+ else if (M_offset > 0)
+ {
+ uint32_t b_seq = min;
+ if ((min == seq_num) && begin_frame)
+ {
+ // Set new Start sequence
+ this_fragmentation->start_index = begin_index;
+ this_fragmentation->start_seq = min;
+ frag_offset = 0;
+ }
+ else
+ {
+ if (min == seq_num)
+ {
+ M_offset--;
+ begin_index = (begin_index ? (begin_index -1) : (MAXFRAGNUM -1));
+ b_seq--;
+ }
+
+ // Find the Begin sequence
+ while (this_fragmentation->fragment[begin_index].length)
+ {
+ if (b_seq == this_fragmentation->fragment[begin_index].seq)
+ {
+ if (this_fragmentation->fragment[begin_index].flags & MP_BEGIN)
+ break;
+ }
+ 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) seq_num:%d frag_index:%d flags:%d is LOST\n",
+ this_fragmentation->fragment[begin_index].seq, begin_index, this_fragmentation->fragment[begin_index].flags);
+ // this frag is lost
+ this_fragmentation->fragment[begin_index].length = 0;
+ this_fragmentation->fragment[begin_index].flags = 0;
+ break;
+ }
+ begin_index = (begin_index ? (begin_index -1) : (MAXFRAGNUM -1));
+ b_seq--;
+ }
+
+ // begin sequence found ?
+ if (this_fragmentation->fragment[begin_index].length)
+ {
+ // Set new Start sequence
+ this_fragmentation->start_index = begin_index;
+ this_fragmentation->start_seq = b_seq;
+ // recalculate the fragment offset from the new begin seq in the bundle
+ frag_offset = (int) (seq_num - b_seq);
+ }
+ }
+ }
projects / l2tpns.git / blobdiff