6loWPAN: Add a little bit of HC1 compression logic.

net/sixlowpan/sixlowpan_hc1.c

@@ -53,6 +53,17 @@
 
 #ifdef CONFIG_NET_6LOWPAN_COMPRESSION_HC1
 
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/* Buffer access helpers */
+
+#define IPv6BUF(dev)  \
+  ((FAR struct ipv6_hdr_s *)((dev)->d_buf))
+#define UDPIPv6BUF(dev) \
+  ((FAR struct udp_hdr_s *)&dev->d_buf[NET_LL_HDRLEN(dev) + IPv6_HDRLEN])
+
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
@@ -136,14 +147,127 @@ void sixlowpan_compresshdr_hc1(FAR struct ieee802154_driver_s *ieee,
  *           fragment.
  *
  * Returned Value:
- *   None
+ *   Zero (OK) is returned on success, on failure a negater errno value is
+ *   returned.
  *
  ****************************************************************************/
 
-void sixlowpan_uncompresshdr_hc1(FAR struct ieee802154_driver_s *ieee,
+int sixlowpan_uncompresshdr_hc1(FAR struct ieee802154_driver_s *ieee,
                                 uint16_t iplen)
 {
-/* REVISIT: To be provided */
+  FAR struct ipv6_hdr_s *ipv6 = IPv6BUF(&ieee->i_dev);
+  FAR uint8_t *hc1 = RIME_HC1_PTR;
+
+  /* Format the IPv6 header in the device d_buf */
+  /* Set version, traffic clase, and flow label */
+
+  ipv6->vtc    = 0x60;  /* Bits 0-3: version, bits 4-7: traffic class (MS) */
+  ipv6->tcf    = 0;     /* Bits 0-3: traffic class (LS), 4-bits: flow label (MS) */
+  ipv6->flow   = 0;     /* 16-bit flow label (LS) */
+
+  /* Use stateless auto-configuration to set source and destination IP
+   * addresses.
+   */
+
+  sixlowpan_ipfromrime(&g_pktaddrs[PACKETBUF_ADDR_SENDER],
+                       &ipv6->srcipaddr);
+  sixlowpan_ipfromrime(&g_pktaddrs[PACKETBUF_ADDR_RECEIVER],
+                       &ipv6->destipaddr);
+  g_uncomp_hdrlen += IPv6_HDRLEN;
+
+  /* len[], proto, and ttl depend on the encoding */
+
+  switch (hc1[RIME_HC1_ENCODING] & 0x06)
+    {
+    case SIXLOWPAN_HC1_NH_ICMP6:
+      ipv6->proto    = IP_PROTO_ICMP6;
+      ipv6->ttl      = hc1[RIME_HC1_TTL];
+      g_rime_hdrlen += SIXLOWPAN_HC1_HDR_LEN;
+      break;
+
+#if CONFIG_NET_TCP
+    case SIXLOWPAN_HC1_NH_TCP:
+      ipv6->proto    = IP_PROTO_TCP;
+      ipv6->ttl      = hc1[RIME_HC1_TTL];
+      g_rime_hdrlen += SIXLOWPAN_HC1_HDR_LEN;
+      break;
+#endif /* CONFIG_NET_TCP */
+
+#if CONFIG_NET_UDP
+    case SIXLOWPAN_HC1_NH_UDP:
+      {
+        FAR struct udp_hdr_s *udp = UDPIPv6BUF(&ieee->i_dev);
+        FAR uint8_t *hcudp = RIME_HC1_HC_UDP_PTR;
+
+        ipv6->proto = IP_PROTO_UDP;
+        if ((hcudp[RIME_HC1_HC_UDP_HC1_ENCODING] & 0x01) != 0)
+          {
+            /* UDP header is compressed with HC_UDP */
+
+            if (hcudp[RIME_HC1_HC_UDP_UDP_ENCODING] !=
+                SIXLOWPAN_HC_UDP_ALL_C)
+              {
+                nwarn("WARNING: sixlowpan (uncompress_hdr), packet not supported");
+                return -EOPNOTSUPP;
+              }
+
+            /* IP TTL */
+
+            ipv6->ttl = hcudp[RIME_HC1_HC_UDP_TTL];
+
+            /* UDP ports, len, checksum */
+
+            udp->srcport =
+              htons(SIXLOWPAN_UDP_PORT_MIN + (hcudp[RIME_HC1_HC_UDP_PORTS] >> 4));
+            udp->destport =
+              htons(SIXLOWPAN_UDP_PORT_MIN + (hcudp[RIME_HC1_HC_UDP_PORTS] & 0x0F));
+
+            memcpy(&udp->udpchksum, &hcudp[RIME_HC1_HC_UDP_CHKSUM], 2);
+
+            g_uncomp_hdrlen += UIP_UDPH_LEN;
+            g_rime_hdrlen   += SIXLOWPAN_HC1_HC_UDP_HDR_LEN;
+          }
+        else
+          {
+            g_rime_hdrlen += SIXLOWPAN_HC1_HDR_LEN;
+          }
+      }
+      break;
+#endif /* CONFIG_NET_UDP */
+
+    default:
+      return -EPROTONOSUPPORT;
+    }
+
+  /* IP length field. */
+
+  if (iplen == 0)
+    {
+      /* This is not a fragmented packet */
+
+      ipv6->len[0] = 0;
+      ipv6->len[1] = ieee->i_dev.d_len - g_rime_hdrlen +  /* REVISIT */
+                     g_uncomp_hdrlen - IPv6_HDRLEN;
+    }
+  else
+    {
+      /* This is a 1st fragment */
+
+      ipv6->len[0] = (iplen - IPv6_HDRLEN) >> 8;
+      ipv6->len[1] = (iplen - IPv6_HDRLEN) & 0x00FF;
+    }
+
+  /* length field in UDP header */
+
+#if CONFIG_NET_UDP
+  if (ipv6->proto == IP_PROTO_UDP)
+    {
+      FAR struct udp_hdr_s *udp = UDPIPv6BUF(&ieee->i_dev);
+      memcpy(&udp->udplen, &ipv6->len[0], 2);
+    }
+#endif
+
+  return;
 }
 
 #endif /* CONFIG_NET_6LOWPAN_COMPRESSION_HC1 */

net/sixlowpan/sixlowpan_input.c

@@ -700,8 +700,12 @@ int sixlowpan_input(FAR struct ieee802154_driver_s *ieee)
 
                   ipv6hdr = (FAR struct ipv6_hdr_s *)(ieee->i_dev.d_buf);
 
-                  /* Get the Rime MAC address of the destination */
+                  /* Get the Rime MAC address of the destination.  This
-#warning Missing logic
+                   * assumes an encoding of the MAC address in the IPv6
+                   * address.
+                   */
+
+                  sixlowpan_rimefromip(ipv6hdr->destipaddr, &destmac);
 
                   /* Convert the outgoing packet into a frame list. */
 

net/sixlowpan/sixlowpan_internal.h

@@ -663,5 +663,27 @@ void sixlowpan_uncompresshdr_hc1(FAR struct ieee802154_driver_s *ieee,
 
 int sixlowpan_frame_hdralloc(FAR struct iob_s *iob, int size);
 
+/****************************************************************************
+ * Name: sixlowpan_ipfromrime and sixlowpan_rimefromip
+ *
+ * Description:
+ *   sixlowpan_ipfromrime: Use stateless auto-configuration to create an IP
+ *   address from a rime address.
+ *
+ *   sixlowpan_rimefromip: Assume stateless auto-configuration to extrate
+ *   the rime address from an IP address
+ *
+ *    128  112  96   80    64   48   32   16
+ *    ---- ---- ---- ----  ---- ---- ---- ----
+ *    fe80 0000 0000 0000  xxxx xxxx 0000 0000 2-byte Rime address (VALID?)
+ *    fe80 0000 0000 0000  xxxx xxxx xxxx xxxx 8-byte Rime address
+ *
+ ****************************************************************************/
+
+void sixlowpan_ipfromrime(FAR const struct rimeaddr_s *rime,
+                          net_ipv6addr_t ipaddr);
+void sixlowpan_rimefromip(const net_ipv6addr_t ipaddr,
+                          FAR struct rimeaddr_s *rime);
+
 #endif /* CONFIG_NET_6LOWPAN */
 #endif /* _NET_SIXLOWPAN_SIXLOWPAN_INTERNAL_H */

net/sixlowpan/sixlowpan_tcpsend.c

@@ -167,8 +167,11 @@ ssize_t psock_6lowpan_tcp_send(FAR struct socket *psock, FAR const void *buf,
 
   psock->s_flags = _SS_SETSTATE(psock->s_flags, _SF_SEND);
 
-  /* Get the Rime MAC address of the destination */
+  /* Get the Rime MAC address of the destination  This assumes an encoding
-#warning Missing logic
+   * of the MAC address in the IPv6 address.
+   */
+
+  sixlowpan_rimefromip(conn->u.ipv6.raddr, &destmac);
 
   /* If routable, then call sixlowpan_send() to format and send the 6loWPAN
    * packet.

net/sixlowpan/sixlowpan_udpsend.c

@@ -168,8 +168,11 @@ ssize_t psock_6lowpan_udp_send(FAR struct socket *psock, FAR const void *buf,
 
   psock->s_flags = _SS_SETSTATE(psock->s_flags, _SF_SEND);
 
-  /* Get the Rime MAC address of the destination */
+  /* Get the Rime MAC address of the destination  This assumes an encoding
-#warning Missing logic
+   * of the MAC address in the IPv6 address.
+   */
+
+  sixlowpan_rimefromip(conn->u.ipv6.raddr, &destmac);
 
   /* If routable, then call sixlowpan_send() to format and send the 6loWPAN
    * packet.

net/sixlowpan/sixlowpan_utils.c

@@ -66,8 +66,11 @@
 #include <nuttx/config.h>
 
 #include <string.h>
+#include <assert.h>
 #include <errno.h>
 
+#include <nuttx/net/sixlowpan.h>
+
 #include "sixlowpan/sixlowpan_internal.h"
 
 #ifdef CONFIG_NET_6LOWPAN
@@ -96,4 +99,60 @@ int sixlowpan_frame_hdralloc(FAR struct iob_s *iob, int size)
   return -ENOMEM;
 }
 
+/****************************************************************************
+ * Name: sixlowpan_ipfromrime
+ *
+ * Description:
+ *   Use stateless auto-configuration to create an IP address from a rime
+ *   address:
+ *
+ *    128  112  96   80    64   48   32   16
+ *    ---- ---- ---- ----  ---- ---- ---- ----
+ *    fe80 0000 0000 0000  xxxx xxxx 0000 0000 2-byte Rime address (VALID?)
+ *    fe80 0000 0000 0000  xxxx xxxx xxxx xxxx 8-byte Rime address
+ *
+ ****************************************************************************/
+
+void sixlowpan_ipfromrime(FAR const struct rimeaddr_s *rime,
+                          net_ipv6addr_t ipaddr)
+{
+  memset(ipaddr, 0, sizeof(net_ipv6addr_t));
+  ipaddr[0] = 0xfe80;
+
+  /* We consider only links with IEEE EUI-64 identifier or IEEE 48-bit MAC
+   * addresses.  NOTE: that CONFIG_NET_6LOWPAN_RIMEADDR_SIZE may be 2 or
+   * 8.  In the case of 2, we treat the address like an 8 byte address with
+   * the lower bytes set to zero.
+   *
+   * REVISIT:  This is just a guess so that I can continue making forward
+   * progress.  What is the correct policy?
+   */
+
+  memcpy(&ipaddr[4], rime, CONFIG_NET_6LOWPAN_RIMEADDR_SIZE);
+}
+
+/****************************************************************************
+ * Name: sixlowpan_rimefromip
+ *
+ * Description:
+ *   Assume stateless auto-configuration to extrate the rime address from
+ *   an IP address:
+ *
+ *    128  112  96   80    64   48   32   16
+ *    ---- ---- ---- ----  ---- ---- ---- ----
+ *    fe80 0000 0000 0000  xxxx xxxx 0000 0000 2-byte Rime address (VALID?)
+ *    fe80 0000 0000 0000  xxxx xxxx xxxx xxxx 8-byte Rime address
+ *
+ ****************************************************************************/
+
+void sixlowpan_rimefromip(const net_ipv6addr_t ipaddr,
+                          FAR struct rimeaddr_s *rime)
+{
+  /* REVISIT: See notes about 2 byte addresses in sixlowpan_ipfromrime() */
+
+  DEBUGASSERT(ipaddr[0] == 0xfe80);
+
+  memcpy(rime, &ipaddr[4], CONFIG_NET_6LOWPAN_RIMEADDR_SIZE);
+}
+
 #endif /* CONFIG_NET_6LOWPAN */