Fix MLPPP functionality.

diff --git a/debian/changelog b/debian/changelog
index 99b2410..df8f8dd 100644 (file)
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,10 @@
+l2tpns (2.2.1-2fdn1.1) unstable; urgency=low
+
+  * Fix MLPPP functionality
+  * Fix warning compilation on ppp.c
+
+ -- Fernando Alves <fernando.alves@sameswireless.fr>  Fri, 03 Feb 2012 16:16:56 +0100
+

 l2tpns (2.2.1-2fdn1) unstable; urgency=low
 
   * Fix binding the CLI to a specific address
 l2tpns (2.2.1-2fdn1) unstable; urgency=low
 
   * Fix binding the CLI to a specific address

diff --git a/l2tpns.c b/l2tpns.c
index 0721f5c..d1c1337 100644 (file)
--- a/l2tpns.c
+++ b/l2tpns.c
@@ -1463,35 +1463,63 @@ static void processipout(uint8_t *buf, int len)
        if(session[s].bundle != 0 && bundle[session[s].bundle].num_of_links > 1)
        {
                // Add on L2TP header
        if(session[s].bundle != 0 && bundle[session[s].bundle].num_of_links > 1)
        {
                // Add on L2TP header

+               sessionidt members[MAXBUNDLESES];

                bundleidt bid = session[s].bundle;
                bundlet *b = &bundle[bid];
                bundleidt bid = session[s].bundle;
                bundlet *b = &bundle[bid];

+               uint32_t num_of_links, nb_opened;
+               int i;

 
 

-               b->current_ses = (b->current_ses + 1) % b->num_of_links;
-               s = b->members[b->current_ses];
+               num_of_links = b->num_of_links;
+               nb_opened = 0;
+               for (i = 0;i < num_of_links;i++)
+               {
+                       s = b->members[i];
+                       if (session[s].ppp.lcp == Opened)
+                       {
+                               members[nb_opened] = s;
+                               nb_opened++;
+                       }
+               }
+
+               if (nb_opened < 1)
+               {
+                       LOG(2, s, t, "MPPP: PROCESSIPOUT ERROR, no session opened in bundle:%d\n", bid);
+                       return;
+               }
+
+               num_of_links = nb_opened;
+               b->current_ses = (b->current_ses + 1) % num_of_links;
+               s = members[b->current_ses];

                t = session[s].tunnel;
                sp = &session[s];
                t = session[s].tunnel;
                sp = &session[s];

-               LOG(4, s, t, "MPPP: (1)Session number becomes: %d\n", s);
-               if(len > MINFRAGLEN)
-               {
-                       // Partition the packet to "bundle[b].num_of_links" fragments
-                       uint32_t num_of_links = b->num_of_links;
-                       uint32_t fraglen = len / num_of_links;
-                       fraglen = (fraglen > session[s].mru ? session[s].mru : fraglen);
-                       uint32_t last_fraglen = fraglen + len % num_of_links;
-                       last_fraglen = (last_fraglen > session[s].mru ? len % num_of_links : last_fraglen);
+
+               if ((num_of_links > 1) && (len > MINFRAGLEN))
+               {
+                       LOG(4, s, t, "MPPP: (1)Session number becomes: %d\n", s);
+
+                       //for rotate traffic among the member links
+                       uint32_t divisor = num_of_links;
+                       if (divisor > 2)
+                               divisor--;
+
+                       // Partition the packet to "num_of_links" fragments
+                       uint32_t fraglen = len / divisor;
+                       uint32_t last_fraglen = fraglen + len % divisor;

                        uint32_t remain = len;
 
                        // send the first packet
                        uint8_t *p = makeppp(fragbuf, sizeof(fragbuf), buf, fraglen, s, t, PPPIP, 0, bid, MP_BEGIN);
                        if (!p) return;
                        tunnelsend(fragbuf, fraglen + (p-fragbuf), t); // send it...
                        uint32_t remain = len;
 
                        // send the first packet
                        uint8_t *p = makeppp(fragbuf, sizeof(fragbuf), buf, fraglen, s, t, PPPIP, 0, bid, MP_BEGIN);
                        if (!p) return;
                        tunnelsend(fragbuf, fraglen + (p-fragbuf), t); // send it...

+

                        // statistics
                        update_session_out_stat(s, sp, fraglen);
                        // statistics
                        update_session_out_stat(s, sp, fraglen);

+

                        remain -= fraglen;
                        while (remain > last_fraglen)
                        { 
                                b->current_ses = (b->current_ses + 1) % num_of_links;
                        remain -= fraglen;
                        while (remain > last_fraglen)
                        { 
                                b->current_ses = (b->current_ses + 1) % num_of_links;

-                               s = b->members[b->current_ses];
+                               s = members[b->current_ses];

                                t = session[s].tunnel;
                                sp = &session[s];
                                LOG(4, s, t, "MPPP: (2)Session number becomes: %d\n", s);
                                t = session[s].tunnel;
                                sp = &session[s];
                                LOG(4, s, t, "MPPP: (2)Session number becomes: %d\n", s);


@@ -1503,7 +1531,7 @@ static void processipout(uint8_t *buf, int len)
                        }
                        // send the last fragment
                        b->current_ses = (b->current_ses + 1) % num_of_links;
                        }
                        // send the last fragment
                        b->current_ses = (b->current_ses + 1) % num_of_links;

-                       s = b->members[b->current_ses];
+                       s = members[b->current_ses];

                        t = session[s].tunnel;
                        sp = &session[s];
                        LOG(4, s, t, "MPPP: (2)Session number becomes: %d\n", s);
                        t = session[s].tunnel;
                        sp = &session[s];
                        LOG(4, s, t, "MPPP: (2)Session number becomes: %d\n", s);


@@ -1516,10 +1544,9 @@ static void processipout(uint8_t *buf, int len)
                }
                else {
                        // Send it as one frame
                }
                else {
                        // Send it as one frame

-                       uint8_t *p = makeppp(fragbuf, sizeof(fragbuf), buf, len, s, t, PPPIP, 0, bid, MP_BOTH_BITS);
+                       uint8_t *p = makeppp(fragbuf, sizeof(fragbuf), buf, len, s, t, PPPIP, 0, 0, 0);

                        if (!p) return;
                        tunnelsend(fragbuf, len + (p-fragbuf), t); // send it...
                        if (!p) return;
                        tunnelsend(fragbuf, len + (p-fragbuf), t); // send it...

-                       LOG(4, s, t, "MPPP: packet sent as one frame\n");

                        update_session_out_stat(s, sp, len);
                }
        }
                        update_session_out_stat(s, sp, len);
                }
        }


@@ -1970,36 +1997,67 @@ void sessionshutdown(sessionidt s, char const *reason, int cdn_result, int cdn_e
                if (session[s].ppp.ipv6cp == Opened && session[s].ipv6prefixlen && del_routes)
                        route6set(s, session[s].ipv6route, session[s].ipv6prefixlen, 0);
                
                if (session[s].ppp.ipv6cp == Opened && session[s].ipv6prefixlen && del_routes)
                        route6set(s, session[s].ipv6route, session[s].ipv6prefixlen, 0);
                

-               if (b) 
+               if (b)

                {
                {

-                       // This session was part of a bundle
-                       bundle[b].num_of_links--;
-                       LOG(3, s, session[s].tunnel, "MPPP: Dropping member link: %d from bundle %d\n",s,b);
-                       if(bundle[b].num_of_links == 0) 
+                       // This session was part of a bundle
+                       bundle[b].num_of_links--;
+                       LOG(3, s, session[s].tunnel, "MPPP: Dropping member link: %d from bundle %d\n",s,b);
+                       if(bundle[b].num_of_links == 0)

                        {
                        {

-                               bundleclear(b);
-                               LOG(3, s, session[s].tunnel, "MPPP: Kill bundle: %d (No remaing member links)\n",b);
-                       }
-                       else 
+                               bundleclear(b);
+                               LOG(3, s, session[s].tunnel, "MPPP: Kill bundle: %d (No remaing member links)\n",b);
+                       }
+                       else 

                        {
                        {

-                               // Adjust the members array to accomodate the new change
-                               uint8_t mem_num = 0;
-                               // It should be here num_of_links instead of num_of_links-1 (previous instruction "num_of_links--")
-                               if(bundle[b].members[bundle[b].num_of_links] != s) 
+                               // Adjust the members array to accomodate the new change
+                               uint8_t mem_num = 0;
+                               // It should be here num_of_links instead of num_of_links-1 (previous instruction "num_of_links--")
+                               if(bundle[b].members[bundle[b].num_of_links] != s)

                                {
                                {

-                                       uint8_t ml;
-                                       for(ml = 0; ml<bundle[b].num_of_links; ml++)
-                                               if(bundle[b].members[ml] == s)
-                                               {
-                                                       mem_num = ml;
-                                                       break;
-                                               }
-                                       bundle[b].members[mem_num] = bundle[b].members[bundle[b].num_of_links];
-                                       LOG(3, s, session[s].tunnel, "MPPP: Adjusted member links array\n");
-                               }
-                       }
-                       cluster_send_bundle(b);
-               }
+                                       uint8_t ml;
+                                       for(ml = 0; ml<bundle[b].num_of_links; ml++)
+                                                       if(bundle[b].members[ml] == s)
+                                                       {
+                                                                       mem_num = ml;
+                                                                       break;
+                                                       }
+                                       bundle[b].members[mem_num] = bundle[b].members[bundle[b].num_of_links];
+                                       LOG(3, s, session[s].tunnel, "MPPP: Adjusted member links array\n");
+
+                                       // If the killed session is the first of the bundle,
+                                       // the new first session must be stored in the cache_ipmap
+                                       // else the function sessionbyip return 0 and the sending not work any more (processipout).
+                                       if (mem_num == 0)
+                                       {
+                                               sessionidt new_s = bundle[b].members[0];
+
+                                               routed = 0;
+                                               // Add the route for this session.
+                                               for (r = 0; r < MAXROUTE && session[new_s].route[r].ip; r++)
+                                               {
+                                                       int i, prefixlen;
+                                                       in_addr_t ip;
+
+                                                       prefixlen = session[new_s].route[r].prefixlen;
+                                                       ip = session[new_s].route[r].ip;
+
+                                                       if (!prefixlen) prefixlen = 32;
+                                                       ip &= 0xffffffff << (32 - prefixlen);   // Force the ip to be the first one in the route.
+
+                                                       for (i = ip; i < ip+(1<<(32-prefixlen)) ; ++i)
+                                                               cache_ipmap(i, new_s);
+                                               }
+                                               cache_ipmap(session[new_s].ip, new_s);
+
+                                               // IPV6 route
+                                               if (session[new_s].ipv6prefixlen)
+                                                       cache_ipv6map(session[new_s].ipv6route, session[new_s].ipv6prefixlen, new_s);
+                                       }
+                               }
+                       }
+
+                       cluster_send_bundle(b);
+        }

        }
 
        if (session[s].throttle_in || session[s].throttle_out) // Unthrottle if throttled.
        }
 
        if (session[s].throttle_in || session[s].throttle_out) // Unthrottle if throttled.


@@ -3092,8 +3150,9 @@ void processudp(uint8_t *buf, int len, struct sockaddr_in *addr)
                        }
 
                        session[s].last_packet = session[s].last_data = time_now;
                        }
 
                        session[s].last_packet = session[s].last_data = time_now;

-                       if (session[s].walled_garden && !config->cluster_iam_master)
+                       if (!config->cluster_iam_master)

                        {
                        {

+                               // The fragments reconstruction is managed by the Master.

                                master_forward_packet(buf, len, addr->sin_addr.s_addr, addr->sin_port);
                                return;
                        }
                                master_forward_packet(buf, len, addr->sin_addr.s_addr, addr->sin_port);
                                return;
                        }

diff --git a/l2tpns.h b/l2tpns.h
index 8e3d26e..953c058 100644 (file)
--- a/l2tpns.h
+++ b/l2tpns.h
@@ -57,10 +57,10 @@
 #define MP_BOTH_BITS    0xC0            // This value is used when both bits (begin and end) are set in MP header
 
 #define MINFRAGLEN     64              // Minumum fragment length
 #define MP_BOTH_BITS    0xC0            // This value is used when both bits (begin and end) are set in MP header
 
 #define MINFRAGLEN     64              // Minumum fragment length

-#define MAXFRAGLEN     750             // Maximum length for Multilink fragment (MTU / 2 sessions)
-#define MAXFRAGNUM     128             // Maximum number of Multilink fragment in a bundle (must be in the form of 2^X)
+#define MAXFRAGLEN     1496    // Maximum length for Multilink fragment (The multilink may contain only one link)
+#define MAXFRAGNUM     512             // Maximum number of Multilink fragment in a bundle (must be in the form of 2^X)

                                        // it's not expected to have a space for more than 10 unassembled packets = 10 * MAXBUNDLESES
                                        // it's not expected to have a space for more than 10 unassembled packets = 10 * MAXBUNDLESES

-#define        MAXFRAGNUM_MASK 127             // Must be equal to MAXFRAGNUM-1
+#define        MAXFRAGNUM_MASK 511             // Must be equal to MAXFRAGNUM-1

 
 // Constants
 #ifndef ETCDIR
 
 // Constants
 #ifndef ETCDIR


@@ -258,6 +258,7 @@ typedef struct {
 
 typedef struct {
        sessionidt sid;                 // Fragment originating session
 
 typedef struct {
        sessionidt sid;                 // Fragment originating session

+       tunnelidt tid;                  // Fragment originating tunnel

        uint8_t flags;                  // MP frame flags
        uint32_t seq;                   // fragment seq num
         uint16_t length;                // Fragment length
        uint8_t flags;                  // MP frame flags
        uint32_t seq;                   // fragment seq num
         uint16_t length;                // Fragment length

diff --git a/ppp.c b/ppp.c
index 4d01e90..9661d5c 100644 (file)
--- a/ppp.c
+++ b/ppp.c
@@ -1809,130 +1809,299 @@ void processipin(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
 // process Multilink PPP packet received
 void processmpin(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
 {
 // process Multilink PPP packet received
 void processmpin(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
 {

-        bundleidt b = session[s].bundle;
+       bundleidt b = session[s].bundle;

        bundlet * this_bundle = &bundle[b];
        bundlet * this_bundle = &bundle[b];

-       uint32_t frag_offset, M_offset;
-       uint16_t frag_index, M_index;
+       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);
        fragmentationt *this_fragmentation = &frag[b];
        uint8_t begin_frame = (*p & MP_BEGIN);

-        uint8_t end_frame = (*p & MP_END);
-        uint32_t seq_num;
+       uint8_t end_frame = (*p & MP_END);
+       uint32_t seq_num, seq_num_next, seq_num_prev;
+       uint32_t i;

        uint8_t flags = *p;
        uint8_t flags = *p;

-       uint16_t begin_index, end_index;
+       uint16_t begin_index, end_index, start_index;

 
        // Perform length checking
 
        // Perform length checking

-        if(l > MAXFRAGLEN)
-        {
-               LOG(2, s, t, "MPPP: discarding fragment larger than MAXFRAGLEN\n");
-               return;
-        }
+       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;
-        }
+       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
        // 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);
-        }
+       /* 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);
+       }

 
 

-       // calculate this fragment's offset from the begin seq in the bundle
-       frag_offset = (seq_num + this_bundle->max_seq - this_fragmentation->start_seq) & (this_bundle->max_seq-1);
+       max_seq = this_bundle->max_seq;
+       maskSeq = max_seq - 1;

 
 

-       // discard this fragment if frag_offset is bigger that the fragmentation buffer size
-       if (frag_offset >= MAXFRAGNUM)
-        {
-               LOG(3, s, t, "MPPP: Index out of range, received more than MAXFRAGNUM fragment (lost frag) seq:%d, begin_seq:%d, bundle:%d, max:%d\n",seq_num, this_fragmentation->start_seq, b, this_bundle->max_seq);
-                return;
-        }
+       /*
+        * 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;

        
        

-       // update M

        sess_local[s].last_seq = seq_num;
        sess_local[s].last_seq = seq_num;

+
+       uint32_t min;
+

        if (seq_num < this_fragmentation->M)
        if (seq_num < this_fragmentation->M)

+       {
+               min = seq_num;

                this_fragmentation->M = seq_num;
                this_fragmentation->M = seq_num;

+       }

        else
        {
        else
        {

-               uint32_t i, min = sess_local[(this_bundle->members[0])].last_seq;;
+               min = sess_local[(this_bundle->members[0])].last_seq;

                for (i = 1; i < this_bundle->num_of_links; i++)
                {
                for (i = 1; i < this_bundle->num_of_links; i++)
                {

-                       uint32_t s_seq = sess_local[(this_bundle->members[i])].last_seq; 
+                       uint32_t s_seq = sess_local[(this_bundle->members[i])].last_seq;

                        if (s_seq < min)
                                min = s_seq;
                }
                this_fragmentation->M = min;
        }
 
                        if (s_seq < min)
                                min = s_seq;
                }
                this_fragmentation->M = min;
        }
 

-       LOG(4, s, t, "MPPP: Setting M to %d\n", this_fragmentation->M); 
-       //calculate M's offset from the begin seq in the bundle
-       M_offset = (this_fragmentation->M + this_bundle->max_seq - this_fragmentation->start_seq) & (this_bundle->max_seq-1);
+       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)
+                       {
+                               if (begin_frame)
+                               {
+                                       // Set new Start sequence
+                                       this_fragmentation->start_index = begin_index;
+                                       this_fragmentation->start_seq = min;
+                                       frag_offset = 0;
+                               }
+                       }
+                       else
+                       {
+                               // 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);
+                               }
+                       }
+               }
+       }
+       else if ((this_fragmentation->fragment[start_index].length) &&
+                        (!(this_fragmentation->fragment[start_index].flags & MP_BEGIN)))
+       {
+               uint32_t f_seq = this_fragmentation->start_seq;
+               end_index = start_index;
+               // Find the Begin sequence
+               while (this_fragmentation->fragment[end_index].length)
+               {
+                       if (f_seq == this_fragmentation->fragment[end_index].seq)
+                       {
+                               if (this_fragmentation->fragment[end_index].flags & MP_BEGIN)
+                                       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: (FIND2) seq_num:%d frag_index:%d flags:%d is LOST\n",
+                                       this_fragmentation->fragment[end_index].seq, end_index, this_fragmentation->fragment[end_index].flags);
+                               // this frag is lost
+                               this_fragmentation->fragment[end_index].length = 0;
+                               this_fragmentation->fragment[end_index].flags = 0;
+                               break;
+                       }
+                       end_index = (end_index +1) & MAXFRAGNUM_MASK;
+                       f_seq++;
+               }
+
+               // Set new Start sequence
+               this_fragmentation->start_index = end_index;
+               this_fragmentation->start_seq = f_seq;
+               // recalculate the fragment offset from the new begin seq in the bundle
+               frag_offset = (int) (seq_num - f_seq);
+       }

 
 

-       //caculate M's index in the fragment array
-       M_index = (M_offset + this_fragmentation->start_index) & MAXFRAGNUM_MASK;
+       // 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, size frag:%d\n", seq_num, this_fragmentation->start_seq, l);
+               return;
+       }
+

        //caculate received fragment's index in the fragment array
        frag_index = (frag_offset + this_fragmentation->start_index) & MAXFRAGNUM_MASK;
 
        //caculate received fragment's index in the fragment array
        frag_index = (frag_offset + this_fragmentation->start_index) & MAXFRAGNUM_MASK;
 

-       //frame with a single fragment
-       if (begin_frame && end_frame)
-       {
-               // process and reset fragmentation
-                LOG(4, s, t, "MPPP: Both bits are set (Begin and End).\n");
-               this_fragmentation->fragment[frag_index].length = l;
-               this_fragmentation->fragment[frag_index].sid = s;
-               this_fragmentation->fragment[frag_index].flags = flags;
-               this_fragmentation->fragment[frag_index].seq = seq_num;
-               this_fragmentation->re_frame_begin_index = frag_index;
-               this_fragmentation->re_frame_end_index = frag_index;
-               processmpframe(s, t, p, l, 0);
-               this_fragmentation->fragment[frag_index].length = 0;
-               this_fragmentation->fragment[frag_index].flags = 0;
-               end_index = frag_index;
-       }
-       else

        {
                // insert the frame in it's place
                fragmentt *this_frag = &this_fragmentation->fragment[frag_index];
        {
                // 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 is LOST\n",
+                               this_frag->seq, frag_index, this_frag->flags);
+

                this_frag->length = l;
                this_frag->sid = s;
                this_frag->flags = flags;
                this_frag->seq = seq_num;
                this_frag->length = l;
                this_frag->sid = s;
                this_frag->flags = flags;
                this_frag->seq = seq_num;

-                memcpy(this_frag->data, p, l);
+               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;
+
+               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 is LOST\n",
+                                       this_fragmentation->fragment[frag_index_next].seq, frag_index_next, this_fragmentation->fragment[frag_index_next].flags);
+                               // 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
+                       }
+               }
+
+               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 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].length = 0;
+                               this_fragmentation->fragment[frag_index_prev].flags = 0;
+
+                               if (end_frame && (!begin_frame)) return; // assembling frame failed
+                       }
+               }
+
+assembling_frame:

                // try to assemble the frame that has the received fragment as a member         
                // get the beginning of this frame
                // try to assemble the frame that has the received fragment as a member         
                // get the beginning of this frame

-               begin_index = end_index = frag_index;
-               while (this_fragmentation->fragment[begin_index].length)
+               begin_index = end_index = this_fragmentation->start_index;
+               if (this_fragmentation->fragment[begin_index].length)

                {
                {

-                       if (this_fragmentation->fragment[begin_index].flags & MP_BEGIN)
-                               break;
-                       begin_index = (begin_index ? (begin_index -1) : (MAXFRAGNUM -1)); 
+                       if (!(this_fragmentation->fragment[begin_index].flags & MP_BEGIN))
+                               return; // assembling frame failed

                }
                }

-
-               // return if a lost fragment is found
-               if (!(this_fragmentation->fragment[begin_index].length))
+               else

                        return; // assembling frame failed
                        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;
                // 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; 
+
+                       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
                }
 
                // return if a lost fragment is found


@@ -1942,35 +2111,37 @@ void processmpin(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
                // 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
                // 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

-               uint32_t i;

 
 

-                       LOG(4, s, t, "MPPP: processing fragments from %d to %d\n", begin_index, end_index);
-                       // Push to the receive buffer
-                                       
+               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)
                for (i = begin_index;; i = (i + 1) & MAXFRAGNUM_MASK)

-                {
+               {

                        this_frag = &this_fragmentation->fragment[i];
                        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);
+                       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);
                        LOG(5, s, t, "MPPP: processing frame at %d, with len %d\n", i, this_frag->length);

-                        cur_len += 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;
                        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);
+                               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;
                        }
                                break;
                        }

-                }
-                // Set reassembled frame length to zero after processing it
-                this_fragmentation->re_frame_len = 0;
+               }
+
+               // 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
                for (i = begin_index;; i = (i + 1) & MAXFRAGNUM_MASK)
                {
                        this_fragmentation->fragment[i].length = 0;      // Indicates that this fragment has been consumed


@@ -1978,20 +2149,32 @@ void processmpin(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
                        if (i == end_index)
                                break;
                }
                        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)
+               {
+                       if (this_fragmentation->fragment[begin_index].seq == this_fragmentation->start_seq)
+                       {
+                               if (this_fragmentation->fragment[begin_index].flags & MP_BEGIN)
+                                       goto assembling_frame;
+                       }
+                       else
+                       {
+                               LOG(3, this_fragmentation->fragment[begin_index].sid, this_fragmentation->fragment[begin_index].tid,
+                                       "MPPP: START 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_fragmentation->fragment[begin_index].length = 0;
+                               this_fragmentation->fragment[begin_index].flags = 0;
+                       }
+               }

        }
        }

-       //discard fragments received before the recently assembled frame
-       begin_index = this_fragmentation->start_index;
-       this_fragmentation->start_index = (end_index + 1) & MAXFRAGNUM_MASK;
-        this_fragmentation->start_seq = (this_fragmentation->fragment[end_index].seq + 1) & (this_bundle->max_seq-1);
-       //clear length and flags of the discarded fragments
-       while (begin_index != this_fragmentation->start_index)
-        {
-                this_fragmentation->fragment[begin_index].flags = 0;
-               this_fragmentation->fragment[begin_index].length = 0;
-                begin_index = (begin_index + 1) & MAXFRAGNUM_MASK;
-        }

 
 

-       LOG(4, s, t, "MPPP after assembling: M index is =%d, start index is = %d, start seq=%d\n",M_index, this_fragmentation->start_index, this_fragmentation->start_seq);     

        return;
 }
 
        return;
 }
 


@@ -2373,7 +2556,7 @@ uint8_t *makeppp(uint8_t *b, int size, uint8_t *p, int l, sessionidt s, tunnelid
 
        if ((b - start) + l > size)
        {
 
        if ((b - start) + l > size)
        {

-               LOG(2, s, t, "makeppp would overflow buffer (size=%d, header+payload=%ld)\n", size, (b - start) + l);
+               LOG(2, s, t, "makeppp would overflow buffer (size=%d, header+payload=%td)\n", size, (b - start) + l);

                return NULL;
        }
 
                return NULL;
        }