6loWPAN: Fixes for fragmented packets. Change fixes some things, breaks other. Lots more to do.

include/nuttx/net/sixlowpan.h

@@ -80,7 +80,7 @@
 
 #define SIXLOWPAN_DISPATCH_FRAG1         0xc0 /* 11000xxx */
 #define SIXLOWPAN_DISPATCH_FRAGN         0xe0 /* 11100xxx */
-#define SIXLOWPAN_DISPATCH_FRAG_MASK     0xf1 /* 11111000 */
+#define SIXLOWPAN_DISPATCH_FRAG_MASK     0xf8 /* 11111000 */
 
 /* HC1 encoding */
 
@@ -398,6 +398,12 @@ struct ieee802154_driver_s
 
   uint16_t i_reasstag;
 
+  /* i_boffset.  Offset to the beginning of data in d_buf.  As each fragment
+   * is received, data is placed at an appriate offset added to this.
+   */
+
+  uint16_t i_boffset;
+
   /* The source MAC address of the fragments being merged */
 
   struct rimeaddr_s i_fragsrc;

net/sixlowpan/sixlowpan_framelist.c

@@ -252,6 +252,7 @@ int sixlowpan_queue_frames(FAR struct ieee802154_driver_s *ieee,
   FAR uint8_t *fptr;
   int framer_hdrlen;
   struct rimeaddr_s bcastmac;
+  uint16_t pktlen;
   uint16_t paysize;
 #ifdef CONFIG_NET_6LOWPAN_FRAG
   uint16_t outlen = 0;
@@ -365,6 +366,7 @@ int sixlowpan_queue_frames(FAR struct ieee802154_driver_s *ieee,
        */
 
       FAR struct iob_s *qtail;
+      FAR uint8_t *frame1;
       int verify;
 
       /* The outbound IPv6 packet is too large to fit into a single 15.4
@@ -383,7 +385,9 @@ int sixlowpan_queue_frames(FAR struct ieee802154_driver_s *ieee,
       DEBUGASSERT(verify == framer_hdrlen);
       UNUSED(verify);
 
-      /* Move HC1/HC06/IPv6 header */
+      /* Move HC1/HC06/IPv6 header to make space for the FRAG1 header at the
+       * beginning of the frame.
+       */
 
       memmove(fptr + SIXLOWPAN_FRAG1_HDR_LEN, fptr, g_frame_hdrlen);
 
@@ -402,11 +406,10 @@ int sixlowpan_queue_frames(FAR struct ieee802154_driver_s *ieee,
        * bytes for all subsequent headers.
        */
 
+      pktlen = buflen + g_uncomp_hdrlen;
       PUTINT16(fptr, RIME_FRAG_DISPATCH_SIZE,
-              ((SIXLOWPAN_DISPATCH_FRAG1 << 8) | buflen));
+               ((SIXLOWPAN_DISPATCH_FRAG1 << 8) | pktlen));
-
       PUTINT16(fptr, RIME_FRAG_TAG, ieee->i_dgramtag);
-      ieee->i_dgramtag++;
 
       g_frame_hdrlen += SIXLOWPAN_FRAG1_HDR_LEN;
 
@@ -414,9 +417,11 @@ int sixlowpan_queue_frames(FAR struct ieee802154_driver_s *ieee,
 
       sixlowpan_copy_protohdr(destip, fptr);
 
-      /* Copy payload and enqueue */
+      /* Copy payload and enqueue.  NOTE that the size is a multiple of eight
+       * bytes.
+       */
 
-      paysize = (CONFIG_NET_6LOWPAN_MAXPAYLOAD - g_frame_hdrlen) & 0xf8;
+      paysize = (CONFIG_NET_6LOWPAN_MAXPAYLOAD - g_frame_hdrlen) & ~7;
       memcpy(fptr + g_frame_hdrlen, buf,  paysize);
 
       /* Set outlen to what we already sent from the IP payload */
@@ -440,10 +445,11 @@ int sixlowpan_queue_frames(FAR struct ieee802154_driver_s *ieee,
 
       /* Create following fragments */
 
-      g_frame_hdrlen = SIXLOWPAN_FRAGN_HDR_LEN;
+      frame1 = iob->io_data;
-
       while (outlen < buflen)
         {
+          uint16_t fragn_hdrlen;
+
           /* Allocate an IOB to hold the next fragment, waiting if
            * necessary.
            */
@@ -459,49 +465,44 @@ int sixlowpan_queue_frames(FAR struct ieee802154_driver_s *ieee,
           iob->io_pktlen = 0;
           fptr           = iob->io_data;
 
-          /* Add the frame header */
+          /* Copy the frame header from first frame, into the correct
+           * location after the FRAGN header.
+           */
 
-          verify = sixlowpan_framecreate(ieee, iob, ieee->i_panid);
+          memmove(fptr + SIXLOWPAN_FRAGN_HDR_LEN,
-          DEBUGASSERT(verify == framer_hdrlen);
+                  frame1 + SIXLOWPAN_FRAG1_HDR_LEN,
-          UNUSED(verify);
+                  framer_hdrlen);
+          fragn_hdrlen = framer_hdrlen;
 
-          /* Move HC1/HC06/IPv6 header */
+          /* Setup up the FRAGN header at the beginning of the frame */
-
-          memmove(fptr + SIXLOWPAN_FRAGN_HDR_LEN, fptr, g_frame_hdrlen);
-
-          /* Setup up the fragment header */
 
           PUTINT16(fptr, RIME_FRAG_DISPATCH_SIZE,
-                  ((SIXLOWPAN_DISPATCH_FRAGN << 8) | buflen));
+                   ((SIXLOWPAN_DISPATCH_FRAGN << 8) | pktlen));
           PUTINT16(fptr, RIME_FRAG_TAG, ieee->i_dgramtag);
           fptr[RIME_FRAG_OFFSET] = outlen >> 3;
 
-          /* Copy protocol header that follows the IPv6 header */
+          fragn_hdrlen += SIXLOWPAN_FRAGN_HDR_LEN;
-
-          sixlowpan_copy_protohdr(destip, fptr);
 
           /* Copy payload and enqueue */
           /* Check for the last fragment */
 
+          paysize = (CONFIG_NET_6LOWPAN_MAXPAYLOAD - fragn_hdrlen) &
+                    SIXLOWPAN_DISPATCH_FRAG_MASK;
           if (buflen - outlen < paysize)
             {
               /* Last fragment, truncate to the correct length */
 
               paysize = buflen - outlen;
             }
-          else
-            {
-              paysize = (CONFIG_NET_6LOWPAN_MAXPAYLOAD - g_frame_hdrlen) & 0xf8;
-            }
 
-          memcpy(fptr + g_frame_hdrlen, buf + outlen, paysize);
+          memcpy(fptr + fragn_hdrlen, buf + outlen, paysize);
 
           /* Set outlen to what we already sent from the IP payload */
 
-          iob->io_len = paysize + g_frame_hdrlen;
+          iob->io_len = paysize + fragn_hdrlen;
           outlen     += paysize;
 
-          ninfo("Fragment offset %d, length %d, tag %d\n",
+          ninfo("Fragment offset=%d, paysize=%d, i_dgramtag=%d\n",
                 outlen >> 3, paysize, ieee->i_dgramtag);
           sixlowpan_dumpbuffer("Outgoing frame",
                                (FAR const uint8_t *)iob->io_data,
@@ -516,6 +517,10 @@ int sixlowpan_queue_frames(FAR struct ieee802154_driver_s *ieee,
 
           ieee->i_framelist->io_pktlen += iob->io_len;
         }
+
+      /* Update the datagram TAG value */
+
+      ieee->i_dgramtag++;
 #else
       nerr("ERROR: Packet too large: %d\n", buflen);
       nerr("       Cannot to be sent without fragmentation support\n");

net/sixlowpan/sixlowpan_input.c

@@ -111,12 +111,26 @@
 
 int sixlowpan_recv_hdrlen(FAR const uint8_t *fptr)
 {
-  uint16_t hdrlen;
+  uint16_t hdrlen = 0;
   uint8_t addrmode;
+  uint8_t tmp;
+
+  /* Check for a fragment header preceding the IEEE802.15.4 FCF */
+
+  tmp = *fptr & SIXLOWPAN_DISPATCH_FRAG_MASK;
+  if (tmp == SIXLOWPAN_DISPATCH_FRAG1)
+    {
+      hdrlen += SIXLOWPAN_FRAG1_HDR_LEN;
+    }
+  else if (tmp == SIXLOWPAN_DISPATCH_FRAGN)
+    {
+      hdrlen += SIXLOWPAN_FRAGN_HDR_LEN;
+    }
 
   /* Minimum header:  2 byte FCF + 1 byte sequence number */
 
-  hdrlen = 3;
+  fptr   += hdrlen;
+  hdrlen += 3;
 
   /* Account for destination address size */
 
@@ -209,9 +223,7 @@ int sixlowpan_recv_hdrlen(FAR const uint8_t *fptr)
 static int sixlowpan_frame_process(FAR struct ieee802154_driver_s *ieee,
                                    FAR struct iob_s *iob)
 {
-  FAR uint8_t *payptr;        /* Pointer to the frame payload */
   FAR uint8_t *hc1;           /* Convenience pointer to HC1 data */
-
   uint16_t fragsize  = 0;     /* Size of the IP packet (read from fragment) */
   uint16_t paysize;           /* Size of the data payload */
   uint8_t fragoffset = 0;     /* Offset of the fragment in the IP packet */
@@ -221,12 +233,13 @@ static int sixlowpan_frame_process(FAR struct ieee802154_driver_s *ieee,
 #ifdef CONFIG_NET_6LOWPAN_FRAG
   bool isfrag        = false;
   bool isfirstfrag   = false;
-  bool islastfrag    = false;
   uint16_t fragtag   = 0;     /* Tag of the fragment */
   systime_t elapsed;          /* Elapsed time */
 #endif /* CONFIG_NET_6LOWPAN_FRAG */
 
-  /* Get a pointer to the payload following the IEEE802.15.4 frame header. */
+  /* Get a pointer to the payload following the IEEE802.15.4 frame header(s).
+   * This size includes both fragmentation and FCF headers.
+   */
 
   hdrsize = sixlowpan_recv_hdrlen(iob->io_data);
   if (hdrsize < 0)
@@ -242,16 +255,13 @@ static int sixlowpan_frame_process(FAR struct ieee802154_driver_s *ieee,
   g_uncomp_hdrlen = 0;
   g_frame_hdrlen  = hdrsize;
 
-  /* Payload starts after the IEEE802.15.4 header */
-
-  payptr = &iob->io_data[hdrsize];
-
 #ifdef CONFIG_NET_6LOWPAN_FRAG
   /* Since we don't support the mesh and broadcast header, the first header
-   * we look for is the fragmentation header
+   * we look for is the fragmentation header.  NOTE that g_frame_hdrlen
+   * already includes the fragementation header, if presetn.
    */
 
-  switch ((GETINT16(payptr, RIME_FRAG_DISPATCH_SIZE) & 0xf800) >> 8)
+  switch ((GETINT16(iob->io_data, RIME_FRAG_DISPATCH_SIZE) & 0xf800) >> 8)
     {
     /* First fragment of new reassembly */
 
@@ -259,15 +269,12 @@ static int sixlowpan_frame_process(FAR struct ieee802154_driver_s *ieee,
       {
         /* Set up for the reassembly */
 
-        fragoffset  = 0;
+        fragsize    = GETINT16(iob->io_data, RIME_FRAG_DISPATCH_SIZE) & 0x07ff;
-        fragsize    = GETINT16(payptr, RIME_FRAG_DISPATCH_SIZE) & 0x07ff;
+        fragtag     = GETINT16(iob->io_data, RIME_FRAG_TAG);
-        fragtag     = GETINT16(payptr, RIME_FRAG_TAG);
 
-        ninfo("FRAG1: size %d, tag %d, offset %d\n",
+        ninfo("FRAG1: fragsize=%d fragtag=%d fragoffset=%d\n",
               fragsize, fragtag, fragoffset);
 
-        g_frame_hdrlen += SIXLOWPAN_FRAG1_HDR_LEN;
-
         /* Indicate the first fragment of the reassembly */
 
         isfirstfrag = true;
@@ -279,32 +286,18 @@ static int sixlowpan_frame_process(FAR struct ieee802154_driver_s *ieee,
       {
         /* Set offset, tag, size.  Offset is in units of 8 bytes. */
 
-        fragoffset  = payptr[RIME_FRAG_OFFSET];
+        fragoffset  = iob->io_data[RIME_FRAG_OFFSET];
-        fragtag     = GETINT16(payptr, RIME_FRAG_TAG);
+        fragtag     = GETINT16(iob->io_data, RIME_FRAG_TAG);
-        fragsize    = GETINT16(payptr, RIME_FRAG_DISPATCH_SIZE) & 0x07ff;
+        fragsize    = GETINT16(iob->io_data, RIME_FRAG_DISPATCH_SIZE) & 0x07ff;
 
-        ninfo("FRAGN: size=%d tag=%d offset=%d\n",
+        ninfo("FRAGN: fragsize=%d fragtag=%d fragoffset=%d\n",
               fragsize, fragtag, fragoffset);
-
-        g_frame_hdrlen += SIXLOWPAN_FRAGN_HDR_LEN;
-
         ninfo("FRAGN: i_accumlen=%d paysize=%u fragsize=%u\n",
               ieee->i_accumlen, iob->io_len - g_frame_hdrlen, fragsize);
 
         /* Indicate that this frame is a another fragment for reassembly */
 
         isfrag = true;
-
-        /* Check if it is the last fragement to be processed.
-         *
-         * If this is the last fragment, we may shave off any extrenous
-         * bytes at the end. We must be liberal in what we accept.
-         */
-
-        if (ieee->i_accumlen + iob->io_len - g_frame_hdrlen >= fragsize)
-          {
-            islastfrag = true;
-          }
       }
       break;
 
@@ -393,6 +386,7 @@ static int sixlowpan_frame_process(FAR struct ieee802154_driver_s *ieee,
            * compression dispatch logic.
            */
 
+          g_uncomp_hdrlen = ieee->i_boffset;
           goto copypayload;
         }
     }
@@ -413,10 +407,6 @@ static int sixlowpan_frame_process(FAR struct ieee802154_driver_s *ieee,
           return OK;
         }
 
-      /* Start reassembly if we received a non-zero length, first fragment */
-
-      if (fragsize > 0)
-        {
       /* Drop the packet if it cannot fit into the d_buf */
 
       if (fragsize > CONFIG_NET_6LOWPAN_MTU)
@@ -425,18 +415,15 @@ static int sixlowpan_frame_process(FAR struct ieee802154_driver_s *ieee,
           return OK;
         }
 
-          /* Set up for the reassembly */
-
       ieee->i_pktlen   = fragsize;
       ieee->i_reasstag = fragtag;
       ieee->i_time     = clock_systimer();
 
-          ninfo("Starting reassembly: i_pktlen %d, i_pktlen %d\n",
+      ninfo("Starting reassembly: i_pktlen %u, i_reasstag %d\n",
             ieee->i_pktlen, ieee->i_reasstag);
 
       rimeaddr_copy(&ieee->i_fragsrc, &g_pktaddrs[PACKETBUF_ADDR_SENDER]);
     }
-    }
 #endif /* CONFIG_NET_6LOWPAN_FRAG */
 
   /* Process next dispatch and headers */
@@ -446,7 +433,13 @@ static int sixlowpan_frame_process(FAR struct ieee802154_driver_s *ieee,
 #ifdef CONFIG_NET_6LOWPAN_COMPRESSION_HC06
   if ((hc1[RIME_HC1_DISPATCH] & SIXLOWPAN_DISPATCH_IPHC_MASK) == SIXLOWPAN_DISPATCH_IPHC)
     {
+      FAR uint8_t *payptr;
+
       ninfo("IPHC Dispatch\n");
+
+      /* Payload starts after the IEEE802.15.4 header(s) */
+
+      payptr = &iob->io_data[g_frame_hdrlen];
       sixlowpan_uncompresshdr_hc06(ieee, fragsize, iob, payptr);
     }
   else
@@ -455,7 +448,13 @@ static int sixlowpan_frame_process(FAR struct ieee802154_driver_s *ieee,
 #ifdef CONFIG_NET_6LOWPAN_COMPRESSION_HC1
   if (hc1[RIME_HC1_DISPATCH] == SIXLOWPAN_DISPATCH_HC1)
     {
+      FAR uint8_t *payptr;
+
       ninfo("HC1 Dispatch\n");
+
+      /* Payload starts after the IEEE802.15.4 header(s) */
+
+      payptr = &iob->io_data[g_frame_hdrlen];
       sixlowpan_uncompresshdr_hc1(ieee, fragsize, iob, payptr);
     }
   else
@@ -468,16 +467,9 @@ static int sixlowpan_frame_process(FAR struct ieee802154_driver_s *ieee,
       ninfo("IPv6 Dispatch\n");
       g_frame_hdrlen  += SIXLOWPAN_IPV6_HDR_LEN;
 
-      /* payptr was set up to begin just after the IPHC bytes.  However,
-       * those bytes are not present for the case of IPv6 dispatch.  Just
-       * reset back to the begnning of the buffer.
-       */
-
-      payptr = iob->io_data;
-
       /* Put uncompressed IP header in d_buf. */
 
-      memcpy(ipv6, payptr + g_frame_hdrlen, IPv6_HDRLEN);
+      memcpy(ipv6, iob->io_data + g_frame_hdrlen, IPv6_HDRLEN);
 
       /* Update g_uncomp_hdrlen and g_frame_hdrlen. */
 
@@ -493,6 +485,18 @@ static int sixlowpan_frame_process(FAR struct ieee802154_driver_s *ieee,
     }
 
 #ifdef CONFIG_NET_6LOWPAN_FRAG
+  /* Non-fragmented and FRAG1 frames pass through here.  Remember the
+   * offset from the beginning of d_buf where be begin placing the data
+   * payload.
+   */
+
+  if (isfirstfrag)
+    {
+      ieee->i_boffset = g_uncomp_hdrlen;
+    }
+
+  /* We branch to here on all good FRAGN frames */
+
 copypayload:
 #endif /* CONFIG_NET_6LOWPAN_FRAG */
 
@@ -512,17 +516,17 @@ copypayload:
 
   /* Sanity-check size of incoming packet to avoid buffer overflow */
 
-  reqsize = g_uncomp_hdrlen + (uint16_t) (fragoffset << 3) + paysize;
+  reqsize = g_uncomp_hdrlen + (fragoffset << 3) + paysize;
   if (reqsize > CONFIG_NET_6LOWPAN_MTU)
     {
-      ninfo("Required buffer size: %d+%d+%d=%d Available: %d\n",
+      ninfo("Required buffer size: %u+%u+%u=%u Available=%u\n",
-            g_uncomp_hdrlen, (int)(fragoffset << 3), paysize,
+            g_uncomp_hdrlen, (fragoffset << 3), paysize,
             reqsize, CONFIG_NET_6LOWPAN_MTU);
       return -ENOMEM;
     }
 
-  memcpy((FAR uint8_t *)ieee->i_dev.d_buf + g_uncomp_hdrlen +
+  memcpy(ieee->i_dev.d_buf + g_uncomp_hdrlen + (fragoffset << 3),
-         (int)(fragoffset << 3), payptr + g_frame_hdrlen,
+         iob->io_data + g_frame_hdrlen,
          paysize);
 
 #ifdef CONFIG_NET_6LOWPAN_FRAG
@@ -532,27 +536,13 @@ copypayload:
 
   if (isfrag)
     {
-      /* Add the size of the header only for the first fragment. */
+      /* Check if it is the last fragment to be processed.
-
+       *
-      if (isfirstfrag)
+       * If this is the last fragment, we may shave off any extrenous
-        {
+       * bytes at the end. We must be liberal in what we accept.
-          ieee->i_accumlen += g_uncomp_hdrlen;
-        }
-
-      /* For the last fragment, we are OK if there is extraneous bytes at the
-       * end of the packet.
        */
 
-      if (islastfrag)
+      ieee->i_accumlen = g_uncomp_hdrlen + (fragoffset << 3) + paysize;
-        {
-          ieee->i_accumlen = fragsize;
-        }
-      else
-        {
-          ieee->i_accumlen += paysize;
-        }
-
-      ninfo("i_accumlen %d, paysize %d\n", ieee->i_accumlen, paysize);
     }
   else
     {
@@ -563,10 +553,10 @@ copypayload:
    * the IP stack
    */
 
-  ninfo("sixlowpan_init i_accumlen %d, ieee->i_pktlen %d\n",
+  ninfo("i_accumlen=%d i_pktlen=%d paysize=%d\n",
-         ieee->i_accumlen, ieee->i_pktlen);
+         ieee->i_accumlen, ieee->i_pktlen, paysize);
 
-  if (ieee->i_accumlen == 0 || ieee->i_accumlen == ieee->i_pktlen)
+  if (ieee->i_accumlen == 0 || ieee->i_accumlen >= ieee->i_pktlen)
     {
       ninfo("IP packet ready (length %d)\n", ieee->i_pktlen);
 

net/sixlowpan/sixlowpan_tcpsend.c

@@ -403,6 +403,8 @@ void sixlowpan_tcp_send(FAR struct net_driver_s *dev)
       else
         {
           struct rimeaddr_s destmac;
+          FAR uint8_t *buf;
+          size_t buflen;
 
           /* Get the Rime MAC address of the destination.  This assumes an
            * encoding of the MAC address in the IPv6 address.
@@ -412,9 +414,12 @@ void sixlowpan_tcp_send(FAR struct net_driver_s *dev)
 
           /* Convert the outgoing packet into a frame list. */
 
+          buf    = dev->d_buf + sizeof(struct ipv6_hdr_s);
+          buflen = dev->d_len - sizeof(struct ipv6_hdr_s);
+
           (void)sixlowpan_queue_frames(
                   (FAR struct ieee802154_driver_s *)dev, ipv6hdr,
-                  dev->d_buf, dev->d_len, &destmac);
+                  buf, buflen, &destmac);
         }
     }