ng_sixlowpan: initial import of IP header compression

Makefile.dep

@@ -95,6 +95,11 @@ ifneq (,$(filter ng_sixlowpan_frag,$(USEMODULE)))
   USEMODULE += vtimer
 endif
 
+ifneq (,$(filter ng_sixlowpan_iphc,$(USEMODULE)))
+  USEMODULE += ng_sixlowpan
+  USEMODULE += ng_sixlowpan_ctx
+endif
+
 ifneq (,$(filter ng_sixlowpan,$(USEMODULE)))
   USEMODULE += ng_ipv6
   USEMODULE += ng_sixlowpan_netif

sys/Makefile

@@ -116,6 +116,9 @@ endif
 ifneq (,$(filter ng_sixlowpan_frag,$(USEMODULE)))
     DIRS += net/network_layer/ng_sixlowpan/frag
 endif
+ifneq (,$(filter ng_sixlowpan_iphc,$(USEMODULE)))
+    DIRS += net/network_layer/ng_sixlowpan/iphc
+endif
 ifneq (,$(filter ng_sixlowpan_netif,$(USEMODULE)))
     DIRS += net/network_layer/ng_sixlowpan/netif
 endif

sys/include/net/ng_sixlowpan.h

@@ -25,6 +25,7 @@
 #include "kernel_types.h"
 
 #include "net/ng_sixlowpan/frag.h"
+#include "net/ng_sixlowpan/iphc.h"
 
 #ifdef __cplusplus
 extern "C" {

sys/include/net/ng_sixlowpan/iphc.h

+/*
+ * Copyright (C) 2015 Martine Lenders <mlenders@inf.fu-berlin.de>
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @defgroup    net_ng_sixlowpan_iphc   IPv6 header compression (IPHC)
+ * @ingroup     net_ng_sixlowpan
+ * @brief       IPv6 header compression for 6LoWPAN.
+ * @{
+ *
+ * @file
+ * @brief   6LoWPAN IPHC definitions
+ *
+ * @author  Martine Lenders <mlenders@inf.fu-berlin.de>
+ */
+#ifndef NG_SIXLOWPAN_IPHC_H_
+#define NG_SIXLOWPAN_IPHC_H_
+
+#include <stdbool.h>
+
+#include "net/ng_pkt.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief   Dispatch mask for LOWPAN_IPHC.
+ */
+#define NG_SIXLOWPAN_IPHC1_DISP_MASK    (0xe0)
+
+/**
+ * @brief   Dispatch for LOWPAN_IPHC.
+ */
+#define NG_SIXLOWPAN_IPHC1_DISP         (0x60)
+
+/**
+ * @brief   Flag for Traffic Class & Flow Label elision (part of first byte of
+ *          LOWPAN_IPHC).
+ * @see <a href="http://tools.ietf.org/html/rfc6282#section-3.1.1">
+ *          RFC 6282, section 3.1.1
+ *      </a>
+ */
+#define NG_SIXLOWPAN_IPHC1_TF           (0x18)
+
+/**
+ * @brief   Flag for Next Header Compression (part of first byte of
+ *          LOWPAN_IPHC).
+ * @see <a href="http://tools.ietf.org/html/rfc6282#section-3.1.1">
+ *          RFC 6282, section 3.1.1
+ *      </a>
+ */
+#define NG_SIXLOWPAN_IPHC1_NH           (0x04)
+
+/**
+ * @brief   Flag for Hop Limit elision (part of first byte of LOWPAN_IPHC).
+ * @see <a href="http://tools.ietf.org/html/rfc6282#section-3.1.1">
+ *          RFC 6282, section 3.1.1
+ *      </a>
+ */
+#define NG_SIXLOWPAN_IPHC1_HL           (0x03)
+
+/**
+ * @brief   Flag for Context Identifier Extention (part of second byte
+ *          of LOWPAN_IPHC).
+ * @see <a href="http://tools.ietf.org/html/rfc6282#section-3.1.1">
+ *          RFC 6282, section 3.1.1
+ *      </a>
+ */
+#define NG_SIXLOWPAN_IPHC2_CID_EXT      (0x80)
+
+/**
+ * @brief   Flag for Source Address Compression (part of second byte
+ *          of LOWPAN_IPHC).
+ * @see <a href="http://tools.ietf.org/html/rfc6282#section-3.1.1">
+ *          RFC 6282, section 3.1.1
+ *      </a>
+ */
+#define NG_SIXLOWPAN_IPHC2_SAC          (0x40)
+
+/**
+ * @brief   Bits for Source Address Mode (part of second byte of
+ *          LOWPAN_IPHC).
+ * @see <a href="http://tools.ietf.org/html/rfc6282#section-3.1.1">
+ *          RFC 6282, section 3.1.1
+ *      </a>
+ */
+#define NG_SIXLOWPAN_IPHC2_SAM          (0x30)
+
+/**
+ * @brief   Flag for Destination Address Compression (part of second
+ *          byte of LOWPAN_IPHC).
+ * @see <a href="http://tools.ietf.org/html/rfc6282#section-3.1.1">
+ *          RFC 6282, section 3.1.1
+ *      </a>
+ */
+#define NG_SIXLOWPAN_IPHC2_DAC          (0x04)
+
+/**
+ * @brief   Bits for Destination Address Mode (part of second byte of
+ *          LOWPAN_IPHC).
+ * @see <a href="http://tools.ietf.org/html/rfc6282#section-3.1.1">
+ *          RFC 6282, section 3.1.1
+ *      </a>
+ */
+#define NG_SIXLOWPAN_IPHC2_DAM          (0x03)
+
+/**
+ * @brief   Flag for Multicast Compression (part of second byte of
+ *          LOWPAN_IPHC).
+ * @see <a href="http://tools.ietf.org/html/rfc6282#section-3.1.1">
+ *          RFC 6282, section 3.1.1
+ *      </a>
+ */
+#define NG_SIXLOWPAN_IPHC2_M            (0x08)
+
+/**
+ * @brief   6LoWPAN IPHC header length
+ */
+#define NG_SIXLOWPAN_IPHC_HDR_LEN       (2)
+
+/**
+ * @brief   6LoWPAN context idendifier extension header length
+ */
+#define NG_SIXLOWPAN_IPHC_CID_EXT_LEN   (1)
+
+/**
+ * @brief   Checks if datagram is an IPHC datagram.
+ *
+ * @param[in] data  Data of a datagram, may not be NULL.
+ *
+ * @return  true, if datagram is an IPHC datagram.
+ * @return  false, if datagram is not an IPHC datagram.
+ */
+static inline bool ng_sixlowpan_iphc_is(uint8_t *data)
+{
+    return ((*data & NG_SIXLOWPAN_IPHC1_DISP_MASK) == NG_SIXLOWPAN_IPHC1_DISP);
+}
+
+/**
+ * @brief   Decompresses a received 6LoWPAN IPHC frame.
+ *
+ * @param[in,out] pkt   A received 6LoWPAN IPHC frame. Will be translated
+ *                      into an IPv6 packet.
+ *
+ * @return  true, on success
+ * @return  false, on error.
+ */
+bool ng_sixlowpan_iphc_decode(ng_pktsnip_t *pkt);
+
+/**
+ * @brief   Compresses a 6LoWPAN for IPHC.
+ *
+ * @param[in,out] pkt   A 6LoWPAN frame with an uncompressed IPv6 header to
+ *                      send. Will be translated to an 6LoWPAN IPHC frame.
+ *
+ * @return  true, on success
+ * @return  false, on error.
+ */
+bool ng_sixlowpan_iphc_encode(ng_pktsnip_t *pkt);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* NG_SIXLOWPAN_IPHC_H_ */
+/** @} */

sys/include/net/ng_sixlowpan/netif.h

@@ -20,6 +20,8 @@
 #ifndef NG_SIXLOWPAN_NETIF_H_
 #define NG_SIXLOWPAN_NETIF_H_
 
+#include <stdbool.h>
+
 #include "kernel_types.h"
 
 #ifdef __cplusplus
@@ -32,6 +34,9 @@ extern "C" {
 typedef struct {
     kernel_pid_t pid;       /**< PID of the interface */
     uint16_t max_frag_size; /**< Maximum fragment size for this interface */
+#ifdef MODULE_NG_SIXLOWPAN_IPHC
+    bool iphc_enabled;      /**< enable or disable IPHC */
+#endif
 } ng_sixlowpan_netif_t;
 
 /**

sys/net/network_layer/ng_sixlowpan/iphc/Makefile

+MODULE = ng_sixlowpan_iphc
+
+include $(RIOTBASE)/Makefile.base

sys/net/network_layer/ng_sixlowpan/netif/ng_sixlowpan_netif.c

@@ -49,6 +49,9 @@ void ng_sixlowpan_netif_add(kernel_pid_t pid, uint16_t max_frag_size)
 
     free_entry->pid = pid;
     free_entry->max_frag_size = max_frag_size;
+#ifdef MODULE_NG_SIXLOWPAN_IPHC
+    free_entry->iphc_enabled = true;
+#endif
     return;
 }
 

sys/net/network_layer/ng_sixlowpan/ng_sixlowpan.c

@@ -19,6 +19,7 @@
 
 #include "net/ng_sixlowpan.h"
 #include "net/ng_sixlowpan/frag.h"
+#include "net/ng_sixlowpan/iphc.h"
 #include "net/ng_sixlowpan/netif.h"
 
 #define ENABLE_DEBUG    (0)
@@ -101,6 +102,18 @@ void _receive(ng_pktsnip_t *pkt)
         return;
     }
 
+#ifdef MODULE_NG_SIXLOWPAN_IPHC
+    if (ng_sixlowpan_iphc_is(payload->data)) {
+        if (!ng_sixlowpan_iphc_decode(pkt)) {
+            DEBUG("6lo: error on IPHC decoding\n");
+            ng_pktbuf_release(pkt);
+            return;
+        }
+        LL_SEARCH_SCALAR(pkt, payload, type, NG_NETTYPE_IPV6);
+
+    }
+#endif
+
     payload->type = NG_NETTYPE_IPV6;
 
     entry = ng_netreg_lookup(NG_NETTYPE_IPV6, NG_NETREG_DEMUX_CTX_ALL);
@@ -151,6 +164,8 @@ void _send(ng_pktsnip_t *pkt)
      * length is the length of the IPv6 datagram + 6LoWPAN dispatches,
      * while the datagram size is the size of only the IPv6 datagram */
     payload_len = ng_pkt_len(ipv6);
+    /* cppcheck: datagram_size will be read by ng_sixlowpan_frag implementation */
+    /* cppcheck-suppress unreadVariable */
     datagram_size = (uint16_t)payload_len;
 
     /* use sixlowpan packet snip as temporary one */
@@ -163,23 +178,6 @@ void _send(ng_pktsnip_t *pkt)
     }
 
     pkt = sixlowpan;
-
-    DEBUG("6lo: Send uncompressed\n");
-
-    sixlowpan = ng_pktbuf_add(NULL, NULL, sizeof(uint8_t), NG_NETTYPE_SIXLOWPAN);
-
-    if (sixlowpan == NULL) {
-        DEBUG("6lo: no space left in packet buffer\n");
-        ng_pktbuf_release(pkt);
-        return;
-    }
-
-    sixlowpan->next = ipv6;
-    pkt->next = sixlowpan;
-    disp = sixlowpan->data;
-    disp[0] = NG_SIXLOWPAN_UNCOMPRESSED;
-    payload_len++;
-
     iface = ng_sixlowpan_netif_get(hdr->if_pid);
 
     if (iface == NULL) {
@@ -192,11 +190,56 @@ void _send(ng_pktsnip_t *pkt)
         }
 
         ng_sixlowpan_netif_add(hdr->if_pid, max_frag_size);
+        iface = ng_sixlowpan_netif_get(hdr->if_pid);
     }
     else {
         max_frag_size = iface->max_frag_size;
     }
 
+#ifdef MODULE_NG_SIXLOWPAN_IPHC
+    if (iface->iphc_enabled) {
+        if (!ng_sixlowpan_iphc_encode(pkt)) {
+            DEBUG("6lo: error on IPHC encoding\n");
+            ng_pktbuf_release(pkt);
+            return;
+        }
+    }
+    else {
+        DEBUG("6lo: Send uncompressed\n");
+
+        sixlowpan = ng_pktbuf_add(NULL, NULL, sizeof(uint8_t),
+                                  NG_NETTYPE_SIXLOWPAN);
+
+        if (sixlowpan == NULL) {
+            DEBUG("6lo: no space left in packet buffer\n");
+            ng_pktbuf_release(pkt);
+            return;
+        }
+
+        sixlowpan->next = ipv6;
+        pkt->next = sixlowpan;
+        disp = sixlowpan->data;
+        disp[0] = NG_SIXLOWPAN_UNCOMPRESSED;
+        payload_len++;
+    }
+#else
+    DEBUG("6lo: Send uncompressed\n");
+
+    sixlowpan = ng_pktbuf_add(NULL, NULL, sizeof(uint8_t), NG_NETTYPE_SIXLOWPAN);
+
+    if (sixlowpan == NULL) {
+        DEBUG("6lo: no space left in packet buffer\n");
+        ng_pktbuf_release(pkt);
+        return;
+    }
+
+    sixlowpan->next = ipv6;
+    pkt->next = sixlowpan;
+    disp = sixlowpan->data;
+    disp[0] = NG_SIXLOWPAN_UNCOMPRESSED;
+    payload_len++;
+#endif
+
     DEBUG("6lo: max_frag_size = %" PRIu16 " for interface %"
           PRIkernel_pid "\n", max_frag_size, hdr->if_pid);