ipcpd: normal: Add operations to get and set the PCI

This adds the operations needed in the normal IPCP to get and set the
Protocol Control Information. It allows to allocate or release space
in the current DU. The struct pci can be serialized into newly
allocate space. Vice versa, a struct pci can be deserialized given a
DU. It allows for decreasing the TTL in the DU and for calculating the
CRC32. The TTL and CRC32 can now be selected when creating a new DIF.

18 files changed, 382 insertions, 317 deletions

diff --git a/include/ouroboros/dif_config.h b/include/ouroboros/dif_config.h
deleted file mode 100644
index 2e354e8c..00000000
--- a/include/ouroboros/dif_config.h
+++ /dev/null
@@ -1,68 +0,0 @@
-/*
- * Ouroboros - Copyright (C) 2016
- *
- * DIF configurations for each IPCP type
- *
- *    Sander Vrijders <sander.vrijders@intec.ugent.be>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- */
-
-#include <stdint.h>
-#include <unistd.h>
-
-#ifndef OUROBOROS_DIF_CONFIG_H
-#define OUROBOROS_DIF_CONFIG_H
-
-enum ipcp_type {
-        IPCP_LOCAL = 0,
-        IPCP_NORMAL,
-        IPCP_SHIM_UDP,
-        IPCP_SHIM_ETH_LLC
-};
-
-struct dif_config {
-        char * dif_name;
-        enum ipcp_type type;
-
-        union {
-                /* Normal DIF */
-                struct {
-                        uint8_t addr_size;
-                        uint8_t cep_id_size;
-                        uint8_t pdu_length_size;
-                        uint8_t seqno_size;
-
-                        /* DUP constants */
-                        uint8_t ttl_size;
-                        uint8_t chk_size;
-
-                        uint32_t min_pdu_size;
-                        uint32_t max_pdu_size;
-                };
-                /* Shim UDP */
-                struct {
-                        uint32_t ip_addr;
-                        uint32_t dns_addr;
-                };
-                /* Shim Ethernet LLC */
-                struct {
-                        char * if_name;
-                };
-        };
-};
-
-
-#endif /* OUROBOROS_DIF_CONFIG_H */
diff --git a/include/ouroboros/irm_config.h b/include/ouroboros/irm_config.h
index d5f2b565..ba58f2f7 100644
--- a/include/ouroboros/irm_config.h
+++ b/include/ouroboros/irm_config.h
@@ -22,6 +22,7 @@
 
 #include <stdint.h>
 #include <unistd.h>
+#include <stdbool.h>
 
 #ifndef OUROBOROS_IRM_CONFIG_H
 #define OUROBOROS_IRM_CONFIG_H
@@ -52,8 +53,8 @@ struct dif_config {
                         uint8_t seqno_size;
 
                         /* DUP constants */
-                        uint8_t ttl_size;
-                        uint8_t chk_size;
+                        bool has_ttl;
+                        bool has_chk;
 
                         uint32_t min_pdu_size;
                         uint32_t max_pdu_size;
diff --git a/include/ouroboros/shm_rdrbuff.h b/include/ouroboros/shm_rdrbuff.h
index 6cdaa7bf..7a7049e3 100644
--- a/include/ouroboros/shm_rdrbuff.h
+++ b/include/ouroboros/shm_rdrbuff.h
@@ -65,20 +65,19 @@ int       shm_rdrbuff_read(uint8_t **           dst,
 int       shm_rdrbuff_remove(struct shm_rdrbuff  * rdrb,
                              ssize_t               idx);
 
+uint8_t * shm_du_buff_head(struct shm_du_buff * sdb);
 
-uint8_t * shm_du_buff_head_alloc(struct shm_rdrbuff * rdrb,
-                                 ssize_t              idx,
+uint8_t * shm_du_buff_tail(struct shm_du_buff * sdb);
+
+uint8_t * shm_du_buff_head_alloc(struct shm_du_buff * sdb,
                                  size_t               size);
 
-uint8_t * shm_du_buff_tail_alloc(struct shm_rdrbuff * rdrb,
-                                 ssize_t              idx,
+uint8_t * shm_du_buff_tail_alloc(struct shm_du_buff * sdb,
                                  size_t               size);
 
-int       shm_du_buff_head_release(struct shm_rdrbuff * rdrb,
-                                   ssize_t              idx,
+int       shm_du_buff_head_release(struct shm_du_buff * sdb,
                                    size_t               size);
 
-int       shm_du_buff_tail_release(struct shm_rdrbuff * rdrb,
-                                   ssize_t              idx,
+int       shm_du_buff_tail_release(struct shm_du_buff * sdb,
                                    size_t               size);
 #endif /* OUROBOROS_SHM_RDRBUFF_H */
diff --git a/src/ipcpd/ipcp.c b/src/ipcpd/ipcp.c
index 12111a51..ec5ab927 100644
--- a/src/ipcpd/ipcp.c
+++ b/src/ipcpd/ipcp.c
@@ -252,12 +252,12 @@ void * ipcp_main_loop(void * o)
                                 conf.cep_id_size = conf_msg->cep_id_size;
                                 conf.pdu_length_size
                                         = conf_msg->pdu_length_size;
-                                conf.qos_id_size     = conf_msg->qos_id_size;
-                                conf.seqno_size      = conf_msg->seqno_size;
-                                conf.ttl_size        = conf_msg->seqno_size;
-                                conf.chk_size        = conf_msg->chk_size;
-                                conf.min_pdu_size    = conf_msg->min_pdu_size;
-                                conf.max_pdu_size    = conf_msg->max_pdu_size;
+                                conf.qos_id_size = conf_msg->qos_id_size;
+                                conf.seqno_size = conf_msg->seqno_size;
+                                conf.has_ttl = conf_msg->has_ttl;
+                                conf.has_chk = conf_msg->has_chk;
+                                conf.min_pdu_size = conf_msg->min_pdu_size;
+                                conf.max_pdu_size = conf_msg->max_pdu_size;
                         }
                         if (conf_msg->ipcp_type == IPCP_SHIM_UDP) {
                                 conf.ip_addr  = conf_msg->ip_addr;
diff --git a/src/ipcpd/normal/CMakeLists.txt b/src/ipcpd/normal/CMakeLists.txt
index 68dca4b3..654bb127 100644
--- a/src/ipcpd/normal/CMakeLists.txt
+++ b/src/ipcpd/normal/CMakeLists.txt
@@ -22,12 +22,14 @@ protobuf_generate_c(FLOW_ALLOC_SRCS FLOW_ALLOC_HDRS
 
 set(SOURCE_FILES
         # Add source files here
-        main.c
+        cdap_request.c
+        crc32.c
         fmgr.c
         frct.c
-        cdap_request.c
+        main.c
         ribmgr.c
         rmt.c
+        shm_pci.c
 )
 
 add_executable (ipcpd-normal ${SOURCE_FILES} ${IPCP_SOURCES}
diff --git a/src/ipcpd/normal/crc32.c b/src/ipcpd/normal/crc32.c
new file mode 100644
index 00000000..ad3e2b35
--- /dev/null
+++ b/src/ipcpd/normal/crc32.c
@@ -0,0 +1,83 @@
+/*
+ * Ouroboros - Copyright (C) 2016
+ *
+ * 32-bit Cyclic Redundancy Check
+ *
+ *    Sander Vrijders   <sander.vrijders@intec.ugent.be>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <stddef.h>
+
+#include "crc32.h"
+
+static const uint32_t crc32_table[256] = {
+  0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
+  0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
+  0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2,
+  0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
+  0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
+  0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
+  0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa, 0x42b2986c,
+  0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
+  0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423,
+  0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
+  0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, 0x01db7106,
+  0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
+  0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d,
+  0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
+  0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
+  0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
+  0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7,
+  0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
+  0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa,
+  0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
+  0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81,
+  0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
+  0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84,
+  0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
+  0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
+  0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
+  0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e,
+  0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
+  0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55,
+  0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
+  0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28,
+  0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
+  0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f,
+  0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
+  0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
+  0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
+  0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69,
+  0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
+  0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc,
+  0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
+  0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693,
+  0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
+  0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
+};
+
+void crc32(uint32_t * crc, const uint8_t * buf, size_t len)
+{
+  size_t n;
+
+  *crc = *crc ^ 0xffffffff;
+
+  for (n = 0; n < len; n++)
+    *crc = crc32_table[(*crc ^ buf[n]) & 0xff] ^ (*crc >> 8);
+
+  *crc = *crc ^ 0xffffffff;
+}
diff --git a/src/ipcpd/normal/crc32.h b/src/ipcpd/normal/crc32.h
new file mode 100644
index 00000000..f22bbc19
--- /dev/null
+++ b/src/ipcpd/normal/crc32.h
@@ -0,0 +1,30 @@
+/*
+ * Ouroboros - Copyright (C) 2016
+ *
+ * 32-bit Cyclic Redundancy Check
+ *
+ *    Sander Vrijders   <sander.vrijders@intec.ugent.be>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#ifndef OUROBOROS_IPCP_CRC32_H
+#define OUROBOROS_IPCP_CRC32_H
+
+#include <stdint.h>
+
+void crc32(uint32_t * crc, const uint8_t * buf, size_t len);
+
+#endif /* OUROBOROS_IPCP_CRC32_H */
diff --git a/src/ipcpd/normal/dt_const.h b/src/ipcpd/normal/dt_const.h
index b33f16c5..eda66838 100644
--- a/src/ipcpd/normal/dt_const.h
+++ b/src/ipcpd/normal/dt_const.h
@@ -25,14 +25,15 @@
 #define IPCP_DT_CONST_H
 
 #include <stdint.h>
+#include <stdbool.h>
 
 struct dt_const {
-        uint8_t addr_size;
-        uint8_t cep_id_size;
-        uint8_t pdu_length_size;
-        uint8_t seqno_size;
-        uint8_t ttl_size;
-        uint8_t chk_size;
+        uint8_t  addr_size;
+        uint8_t  cep_id_size;
+        uint8_t  pdu_length_size;
+        uint8_t  seqno_size;
+        bool     has_ttl;
+        bool     has_chk;
         uint32_t min_pdu_size;
         uint32_t max_pdu_size;
 };
diff --git a/src/ipcpd/normal/frct.c b/src/ipcpd/normal/frct.c
index 7c2eba61..417815b7 100644
--- a/src/ipcpd/normal/frct.c
+++ b/src/ipcpd/normal/frct.c
@@ -126,6 +126,14 @@ int frct_fini()
         return 0;
 }
 
+struct dt_const * frct_dt_const()
+{
+        if (frct == NULL)
+                return NULL;
+
+        return frct->dtc;
+}
+
 int frct_dt_flow(int fd,
                  enum qos_cube qos)
 {
diff --git a/src/ipcpd/normal/frct.h b/src/ipcpd/normal/frct.h
index 91b2dfc7..09873445 100644
--- a/src/ipcpd/normal/frct.h
+++ b/src/ipcpd/normal/frct.h
@@ -30,26 +30,29 @@
 
 struct frct_i;
 
-int             frct_init(struct dt_const * dtc,
-                          uint32_t address);
-int             frct_fini();
+int               frct_init(struct dt_const * dtc,
+                            uint32_t address);
+int               frct_fini();
+
+struct dt_const * frct_dt_const();
+
+int               frct_dt_flow(int fd,
+                               enum qos_cube qos);
 
-int             frct_dt_flow(int fd,
-                             enum qos_cube qos);
 /*
  * FIXME: Will take the index in the DU map,
  * possibly cep-ids and address
  */
-int             frct_rmt_post();
+int                frct_rmt_post();
 
-struct frct_i * frct_i_create(uint32_t      address,
-                              buffer_t *    buf,
-                              enum qos_cube cube);
+struct frct_i *    frct_i_create(uint32_t      address,
+                                 buffer_t *    buf,
+                                 enum qos_cube cube);
 /* FIXME: Hand QoS cube here too? We received it in the flow alloc message. */
-int             frct_i_accept(struct frct_i * instance,
-                              buffer_t *      buf);
-int             frct_i_destroy(struct frct_i * instance,
-                               buffer_t *      buf);
+int                frct_i_accept(struct frct_i * instance,
+                                 buffer_t *      buf);
+int                frct_i_destroy(struct frct_i * instance,
+                                  buffer_t *      buf);
 
 /* FIXME: Add read/write ops for frct instances */
 
diff --git a/src/ipcpd/normal/ribmgr.c b/src/ipcpd/normal/ribmgr.c
index 007361fd..9733abc9 100644
--- a/src/ipcpd/normal/ribmgr.c
+++ b/src/ipcpd/normal/ribmgr.c
@@ -241,8 +241,8 @@ int ribmgr_cdap_write(struct cdap * instance,
                 rib->dtc.cep_id_size = msg->cep_id_size;
                 rib->dtc.pdu_length_size = msg->pdu_length_size;
                 rib->dtc.seqno_size = msg->seqno_size;
-                rib->dtc.ttl_size = msg->ttl_size;
-                rib->dtc.chk_size = msg->chk_size;
+                rib->dtc.has_ttl = msg->has_ttl;
+                rib->dtc.has_chk = msg->has_chk;
                 rib->dtc.min_pdu_size = msg->min_pdu_size;
                 rib->dtc.max_pdu_size = msg->max_pdu_size;
 
@@ -318,8 +318,8 @@ int ribmgr_cdap_start(struct cdap * instance,
                 stat_info.cep_id_size = rib->dtc.cep_id_size;
                 stat_info.pdu_length_size = rib->dtc.pdu_length_size;
                 stat_info.seqno_size = rib->dtc.seqno_size;
-                stat_info.ttl_size = rib->dtc.ttl_size;
-                stat_info.chk_size = rib->dtc.chk_size;
+                stat_info.has_ttl = rib->dtc.has_ttl;
+                stat_info.has_chk = rib->dtc.has_chk;
                 stat_info.min_pdu_size  = rib->dtc.min_pdu_size;
                 stat_info.max_pdu_size = rib->dtc.max_pdu_size;
 
@@ -529,8 +529,8 @@ int ribmgr_bootstrap(struct dif_config * conf)
         rib->dtc.cep_id_size  = conf->cep_id_size;
         rib->dtc.pdu_length_size = conf->pdu_length_size;
         rib->dtc.seqno_size = conf->seqno_size;
-        rib->dtc.ttl_size = conf->ttl_size;
-        rib->dtc.chk_size = conf->chk_size;
+        rib->dtc.has_ttl = conf->has_ttl;
+        rib->dtc.has_chk = conf->has_chk;
         rib->dtc.min_pdu_size = conf->min_pdu_size;
         rib->dtc.max_pdu_size = conf->max_pdu_size;
 
diff --git a/src/ipcpd/normal/shm_pci.c b/src/ipcpd/normal/shm_pci.c
index 144bd15e..94629790 100644
--- a/src/ipcpd/normal/shm_pci.c
+++ b/src/ipcpd/normal/shm_pci.c
@@ -21,127 +21,183 @@
  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
-#include <ourboros/errno.h>
-
-#include "shm_pci.h"
-#include <stdlib.h>
-
-#define SHM_PCI_HEAD_SIZE(a, b) a.addr_size * 2 +  \
-        a.cep_id_size * 2 +                    \
-        a.pdu_length_size +                    \
-        b.ttl_size +                           \
-        a.seqno_size +                         \
-        a.qos_id_size
-#define SHM_PCI_TAIL_SIZE(b) b.chk_size
-
 #define OUROBOROS_PREFIX "ipcpd/shm_pci"
 
 #include <ouroboros/logs.h>
+#include <ouroboros/errno.h>
 
-struct shm_pci {
-        /* head */
-        uint8_t * dst_addr;
-        uint8_t * src_addr;
-        uint8_t * dst_cep_id;
-        uint8_t * src_cep_id;
-        uint8_t * pdu_length;
-        uint8_t * ttl;
-        uint8_t * seqno;
-        uint8_t * qos_id;
+#include <stdlib.h>
+#include <string.h>
 
-        uint8_t * chk;
+#include "shm_pci.h"
+#include "frct.h"
+#include "crc32.h"
 
-        struct shm_du_buff * dub;
+#define QOS_ID_SIZE 1
+#define DEFAULT_TTL 60
+#define TTL_SIZE 1
+#define CHK_SIZE 4
 
-        struct ipcp_dtp_const dtpc;
-        struct ipcp_dup_const dupc;
+static int shm_pci_head_size(struct dt_const * dtc)
+{
+        int len = 0;
 
-};
+        len = dtc->addr_size * 2 + dtc->cep_id_size * 2
+                + dtc->pdu_length_size + dtc->seqno_size
+                + QOS_ID_SIZE;
 
-shm_pci_t * shm_pci_create(struct shm_du_buff      * dub,
-                           const struct ipcp_dtp_const * dtpc,
-                           const struct ipcp_dup_const * dupc)
+        if (dtc->has_ttl)
+                len += TTL_SIZE;
+
+        return len;
+}
+
+static int shm_pci_tail_size(struct dt_const * dtc)
 {
-        struct shm_pci * p;
+        return dtc->has_chk ? CHK_SIZE : 0;
+}
 
-        if (dub == NULL) {
-                LOG_DBGF("Bogus input. Bugging out.");
-                return NULL;
+int shm_pci_ser(struct shm_du_buff * sdb,
+                struct pci * pci)
+{
+        uint8_t * head;
+        uint8_t * tail;
+        int offset = 0;
+        struct dt_const * dtc;
+        uint8_t ttl = DEFAULT_TTL;
+
+        dtc = frct_dt_const();
+        if (dtc == NULL)
+                return -1;
+
+        head = shm_du_buff_head_alloc(sdb, shm_pci_head_size(dtc));
+        if (head == NULL)
+                return -1;
+
+        memcpy(head, &pci->dst_addr, dtc->addr_size);
+        offset += dtc->addr_size;
+        memcpy(head + offset, &pci->src_addr, dtc->addr_size);
+        offset += dtc->addr_size;
+        memcpy(head + offset, &pci->dst_cep_id, dtc->cep_id_size);
+        offset += dtc->cep_id_size;
+        memcpy(head + offset, &pci->src_cep_id, dtc->cep_id_size);
+        offset += dtc->cep_id_size;
+        memcpy(head + offset, &pci->pdu_length, dtc->pdu_length_size);
+        offset += dtc->pdu_length_size;
+        memcpy(head + offset, &pci->seqno, dtc->seqno_size);
+        offset += dtc->seqno_size;
+        memcpy(head + offset, &pci->qos_id, QOS_ID_SIZE);
+        offset += QOS_ID_SIZE;
+        if (dtc->has_ttl)
+                memcpy(head + offset, &ttl, TTL_SIZE);
+
+        if (dtc->has_chk) {
+                tail = shm_du_buff_tail_alloc(sdb, shm_pci_tail_size(dtc));
+                if (tail == NULL) {
+                        shm_du_buff_head_release(sdb, shm_pci_tail_size(dtc));
+                        return -1;
+                }
+
+                crc32((uint32_t *) tail, head, tail - head);
         }
 
-        p = malloc(sizeof *p);
+        return 0;
+}
 
-        if (p == NULL)
-                return NULL;
+struct pci * shm_pci_des(struct shm_du_buff * sdb)
+{
+        uint8_t * head;
+        struct pci * pci;
+        int offset = 0;
+        struct dt_const * dtc;
 
-        p->dub = dub;
+        head = shm_du_buff_head(sdb);
+        if (head == NULL)
+                return NULL;
 
-        p->dtpc = *dtpc;
-        p->dupc = *dupc;
+        dtc = frct_dt_const();
+        if (dtc == NULL)
+                return NULL;
 
-        p->dst_addr   = NULL;
-        p->src_addr   = NULL;
-        p->dst_cep_id = NULL;
-        p->src_cep_id = NULL;
-        p->pdu_length = NULL;
-        p->ttl        = NULL;
-        p->seqno      = NULL;
-        p->qos_id     = NULL;
-        p->chk        = NULL;
+        pci = malloc(sizeof(*pci));
+        if (pci == NULL)
+                return NULL;
 
-        return p;
+        memcpy(&pci->dst_addr, head, dtc->addr_size);
+        offset += dtc->addr_size;
+        memcpy(&pci->src_addr, head + offset, dtc->addr_size);
+        offset += dtc->addr_size;
+        memcpy(&pci->dst_cep_id, head + offset, dtc->cep_id_size);
+        offset += dtc->cep_id_size;
+        memcpy(&pci->src_cep_id, head + offset, dtc->cep_id_size);
+        offset += dtc->cep_id_size;
+        memcpy(&pci->pdu_length, head + offset, dtc->pdu_length_size);
+        offset += dtc->pdu_length_size;
+        memcpy(&pci->seqno, head + offset, dtc->seqno_size);
+        offset += dtc->seqno_size;
+        memcpy(&pci->qos_id, head + offset, QOS_ID_SIZE);
+        offset += QOS_ID_SIZE;
+        if (dtc->has_ttl)
+                memcpy(&pci->ttl, head + offset, TTL_SIZE);
+
+        return pci;
 }
 
-void shm_pci_destroy(shm_pci_t * pci)
+int shm_pci_shrink(struct shm_du_buff * sdb)
 {
-        free(pci);
-}
+        struct dt_const * dtc;
 
-int shm_pci_init(shm_pci_t * pci)
-{
-        if (pci == NULL) {
-                LOG_DBGF("Bogus input. Bugging out.");
-                return -EINVAL;
-        }
+        if (sdb == NULL)
+                return -1;
 
-        uint8_t * pci_head = shm_du_buff_head_alloc(
-                pci->dub, SHM_PCI_HEAD_SIZE(pci->dtpc, pci->dupc));
-        uint8_t * pci_tail = shm_du_buff_tail_alloc(
-                pci->dub, SHM_PCI_TAIL_SIZE(pci->dupc));
+        dtc = frct_dt_const();
+        if (dtc == NULL)
+                return -1;
 
-        if (pci_head == NULL) {
-                LOG_DBG("Failed to allocate space for PCI at head.");
-                return -ENOBUFS;
+        if (shm_du_buff_head_release(sdb, shm_pci_head_size(dtc))) {
+                LOG_ERR("Failed to shrink head.");
+                return -1;
         }
 
-        if (pci_tail == NULL) {
-                LOG_DBG("Failed to allocate space for PCI at tail.");
-                return -ENOBUFS;
+        if (shm_du_buff_tail_release(sdb, shm_pci_tail_size(dtc))) {
+                LOG_ERR("Failed to shrink tail.");
+                return -1;
         }
 
-        pci->dst_addr   = pci_head;
-        pci->src_addr   = (pci_head += pci->dtpc.addr_size);
-        pci->dst_cep_id = (pci_head += pci->dtpc.addr_size);
-        pci->src_cep_id = (pci_head += pci->dtpc.cep_id_size);
-        pci->pdu_length = (pci_head += pci->dtpc.cep_id_size);
-        pci->ttl        = (pci_head += pci->dtpc.pdu_length_size);
-        pci->seqno      = (pci_head += pci->dupc.ttl_size);
-        pci->qos_id     = (pci_head += pci->dtpc.seqno_size);
-
-        pci->chk        = (pci_tail);
-
         return 0;
 }
 
-void shm_pci_release(shm_pci_t * pci)
+int shm_pci_dec_ttl(struct shm_du_buff * sdb)
 {
-        if (pci == NULL)
-                return;
+        struct dt_const * dtc;
+        int offset = 0;
+        uint8_t * head;
+        uint8_t * tail;
 
-        if (pci->dub == NULL)
-                return;
+        dtc = frct_dt_const();
+        if (dtc == NULL)
+                return -1;
 
-        shm_du_buff_head_release(pci->dub, SHM_PCI_HEAD_SIZE(pci->dtpc,
-                                                             pci->dupc));
-        shm_du_buff_tail_release(pci->dub, SHM_PCI_TAIL_SIZE(pci->dupc));
+        if (dtc->has_ttl == false)
+                return 0;
+
+        offset = shm_pci_head_size(dtc) - 1;
+
+        head = shm_du_buff_head(sdb);
+        if (head == NULL)
+                return -1;
+
+        head[offset]--;
+
+        if (dtc->has_chk) {
+                tail = shm_du_buff_tail(sdb);
+                if (tail == NULL)
+                        return -1;
+
+                tail -= CHK_SIZE;
+
+                crc32((uint32_t *) tail, head, tail - head);
+        }
+
+        return 0;
 }
diff --git a/src/ipcpd/normal/shm_pci.h b/src/ipcpd/normal/shm_pci.h
index cb8dd5dd..aa9770b4 100644
--- a/src/ipcpd/normal/shm_pci.h
+++ b/src/ipcpd/normal/shm_pci.h
@@ -24,20 +24,28 @@
 #ifndef OUROBOROS_IPCP_SHM_PCI_H
 #define OUROBOROS_IPCP_SHM_PCI_H
 
-#include <ouroboros/shm_du_map.h>
+#include <ouroboros/shm_rdrbuff.h>
 
 #include <dt_const.h>
 
-struct shm_pci;
+struct pci {
+        uint64_t dst_addr;
+        uint64_t src_addr;
+        uint32_t dst_cep_id;
+        uint32_t src_cep_id;
+        uint32_t pdu_length;
+        uint64_t seqno;
+        uint8_t  qos_id;
+        uint8_t  ttl;
+};
 
-typedef struct shm_pci shm_pci_t;
+int          shm_pci_ser(struct shm_du_buff * sdb,
+                         struct pci * pci);
 
-shm_pci_t * shm_pci_create(struct shm_du_buff          * dub,
-                           const struct ipcp_dtp_const * dtpc,
-                           const struct ipcp_dup_const * dupc);
-void    shm_pci_destroy(shm_pci_t * pci);
+struct pci * shm_pci_des(struct shm_du_buff * sdb);
 
-int     shm_pci_init(shm_pci_t * pci);
-void    shm_pci_release(shm_pci_t * pci);
+int          shm_pci_shrink(struct shm_du_buff * sdb);
+
+int          shm_pci_dec_ttl(struct shm_du_buff * sdb);
 
 #endif /* OUROBOROS_IPCP_SHM_PCI_H */
diff --git a/src/ipcpd/normal/static_info.proto b/src/ipcpd/normal/static_info.proto
index 24b7994a..04824a38 100644
--- a/src/ipcpd/normal/static_info.proto
+++ b/src/ipcpd/normal/static_info.proto
@@ -3,8 +3,8 @@ message static_info_msg {
         required uint32 cep_id_size     = 2;
         required uint32 pdu_length_size = 3;
         required uint32 seqno_size      = 4;
-        required uint32 ttl_size        = 5;
-        required uint32 chk_size        = 6;
+        required bool   has_ttl         = 5;
+        required bool   has_chk         = 6;
         required uint32 min_pdu_size    = 7;
         required uint32 max_pdu_size    = 8;
         required uint32 address         = 9;
diff --git a/src/lib/dif_config.proto b/src/lib/dif_config.proto
index dbdf19e5..338634d1 100644
--- a/src/lib/dif_config.proto
+++ b/src/lib/dif_config.proto
@@ -7,8 +7,8 @@ message dif_config_msg {
         optional uint32 pdu_length_size =  5;
         optional uint32 qos_id_size     =  6;
         optional uint32 seqno_size      =  7;
-        optional uint32 ttl_size        =  8;
-        optional uint32 chk_size        =  9;
+        optional bool has_ttl           =  8;
+        optional bool has_chk           =  9;
         optional uint32 min_pdu_size    = 10;
         optional uint32 max_pdu_size    = 11;
         // Config for shim UDP
diff --git a/src/lib/irm.c b/src/lib/irm.c
index 64a4fa0f..fce11ba5 100644
--- a/src/lib/irm.c
+++ b/src/lib/irm.c
@@ -115,8 +115,8 @@ int irm_bootstrap_ipcp(pid_t               api,
                 config.has_pdu_length_size = true;
                 config.has_qos_id_size = true;
                 config.has_seqno_size = true;
-                config.has_ttl_size = true;
-                config.has_chk_size = true;
+                config.has_has_ttl = true;
+                config.has_has_chk = true;
                 config.has_min_pdu_size = true;
                 config.has_max_pdu_size = true;
 
@@ -125,8 +125,8 @@ int irm_bootstrap_ipcp(pid_t               api,
                 config.pdu_length_size = conf->pdu_length_size;
                 config.qos_id_size = conf->qos_id_size;
                 config.seqno_size = conf->seqno_size;
-                config.ttl_size = conf->ttl_size;
-                config.chk_size = conf->chk_size;
+                config.has_ttl = conf->has_ttl;
+                config.has_chk = conf->has_chk;
                 config.min_pdu_size = conf->min_pdu_size;
                 config.max_pdu_size = conf->max_pdu_size;
                 break;
diff --git a/src/lib/shm_rdrbuff.c b/src/lib/shm_rdrbuff.c
index 93a889ce..b0d295d9 100644
--- a/src/lib/shm_rdrbuff.c
+++ b/src/lib/shm_rdrbuff.c
@@ -690,32 +690,32 @@ int shm_rdrbuff_remove(struct shm_rdrbuff * rdrb, ssize_t idx)
         return 0;
 }
 
-uint8_t * shm_du_buff_head_alloc(struct shm_rdrbuff * rdrb,
-                                 ssize_t              idx,
-                                 size_t               size)
+uint8_t * shm_du_buff_head(struct shm_du_buff * sdb)
 {
-        struct shm_du_buff * sdb;
-        uint8_t * buf;
-
-        if (rdrb  == NULL)
+        if (sdb == NULL)
                 return NULL;
 
-        if (idx < 0 || idx > SHM_BUFFER_SIZE)
+        return (uint8_t *) (sdb + 1) + sdb->du_head;
+}
+
+uint8_t * shm_du_buff_tail(struct shm_du_buff * sdb)
+{
+        if (sdb == NULL)
                 return NULL;
 
-#ifdef __APPLE__
-        pthread_mutex_lock(rdrb->lock);
-#else
-        if (pthread_mutex_lock(rdrb->lock) == EOWNERDEAD) {
-                LOG_DBGF("Recovering dead mutex.");
-                pthread_mutex_consistent(rdrb->lock);
-        }
-#endif
-        sdb = idx_to_du_buff_ptr(rdrb, idx);
+        return (uint8_t *) (sdb + 1) + sdb->du_tail;
+}
+
+uint8_t * shm_du_buff_head_alloc(struct shm_du_buff * sdb,
+                                 size_t               size)
+{
+        uint8_t * buf = NULL;
+
+        if (sdb  == NULL)
+                return NULL;
 
         if ((long) (sdb->du_head - size) < 0) {
-                pthread_mutex_unlock(rdrb->lock);
-                LOG_DBGF("Failed to allocate PCI headspace.");
+                LOG_ERR("Failed to allocate PCI headspace.");
                 return NULL;
         }
 
@@ -723,37 +723,19 @@ uint8_t * shm_du_buff_head_alloc(struct shm_rdrbuff * rdrb,
 
         buf = (uint8_t *) (sdb + 1) + sdb->du_head;
 
-        pthread_mutex_unlock(rdrb->lock);
-
         return buf;
 }
 
-uint8_t * shm_du_buff_tail_alloc(struct shm_rdrbuff * rdrb,
-                                 ssize_t              idx,
+uint8_t * shm_du_buff_tail_alloc(struct shm_du_buff * sdb,
                                  size_t               size)
 {
-        struct shm_du_buff * sdb;
-        uint8_t * buf;
-
-        if (rdrb  == NULL)
-                return NULL;
+        uint8_t * buf = NULL;
 
-        if (idx < 0 || idx > SHM_BUFFER_SIZE)
+        if (sdb  == NULL)
                 return NULL;
 
-#ifdef __APPLE__
-        pthread_mutex_lock(rdrb->lock);
-#else
-        if (pthread_mutex_lock(rdrb->lock) == EOWNERDEAD) {
-                LOG_DBGF("Recovering dead mutex.");
-                pthread_mutex_consistent(rdrb->lock);
-        }
-#endif
-        sdb = idx_to_du_buff_ptr(rdrb, idx);
-
         if (sdb->du_tail + size >= sdb->size) {
-                pthread_mutex_unlock(rdrb->lock);
-                LOG_DBGF("Failed to allocate PCI tailspace.");
+                LOG_ERR("Failed to allocate PCI tailspace.");
                 return NULL;
         }
 
@@ -761,78 +743,37 @@ uint8_t * shm_du_buff_tail_alloc(struct shm_rdrbuff * rdrb,
 
         sdb->du_tail += size;
 
-        pthread_mutex_unlock(rdrb->lock);
-
         return buf;
 }
 
-int shm_du_buff_head_release(struct shm_rdrbuff * rdrb,
-                             ssize_t              idx,
+int shm_du_buff_head_release(struct shm_du_buff * sdb,
                              size_t               size)
 {
-        struct shm_du_buff * sdb;
-
-        if (rdrb  == NULL)
-                return -1;
-
-        if (idx < 0 || idx > SHM_BUFFER_SIZE)
+        if (sdb  == NULL)
                 return -1;
 
-#ifdef __APPLE__
-        pthread_mutex_lock(rdrb->lock);
-#else
-        if (pthread_mutex_lock(rdrb->lock) == EOWNERDEAD) {
-                LOG_DBGF("Recovering dead mutex.");
-                pthread_mutex_consistent(rdrb->lock);
-        }
-#endif
-
-        sdb = idx_to_du_buff_ptr(rdrb, idx);
-
         if (size > sdb->du_tail - sdb->du_head) {
-                pthread_mutex_unlock(rdrb->lock);
-                LOG_DBGF("Tried to release beyond sdu boundary.");
+                LOG_DBGF("Tried to release beyond SDU boundary.");
                 return -EOVERFLOW;
         }
 
         sdb->du_head += size;
 
-        pthread_mutex_unlock(rdrb->lock);
-
         return 0;
 }
 
-int shm_du_buff_tail_release(struct shm_rdrbuff * rdrb,
-                             ssize_t              idx,
+int shm_du_buff_tail_release(struct shm_du_buff * sdb,
                              size_t               size)
 {
-        struct shm_du_buff * sdb;
-
-        if (rdrb  == NULL)
-                return -1;
-
-        if (idx < 0 || idx > SHM_BUFFER_SIZE)
+        if (sdb  == NULL)
                 return -1;
 
-#ifdef __APPLE__
-        pthread_mutex_lock(rdrb->lock);
-#else
-        if (pthread_mutex_lock(rdrb->lock) == EOWNERDEAD) {
-                LOG_DBGF("Recovering dead mutex.");
-                pthread_mutex_consistent(rdrb->lock);
-        }
-#endif
-        sdb = idx_to_du_buff_ptr(rdrb, idx);
-
         if (size > sdb->du_tail - sdb->du_head) {
-                pthread_mutex_unlock(rdrb->lock);
-                LOG_DBGF("Tried to release beyond sdu boundary.");
+                LOG_ERR("Tried to release beyond SDU boundary.");
                 return -EOVERFLOW;
         }
 
         sdb->du_tail -= size;
 
-        pthread_mutex_unlock(rdrb->lock);
-
         return 0;
 }
diff --git a/src/tools/irm/irm_ipcp_bootstrap.c b/src/tools/irm/irm_ipcp_bootstrap.c
index 3db43e6e..ba9b7e2e 100644
--- a/src/tools/irm/irm_ipcp_bootstrap.c
+++ b/src/tools/irm/irm_ipcp_bootstrap.c
@@ -42,8 +42,6 @@
 #define DEFAULT_CEP_ID_SIZE 2
 #define DEFAULT_PDU_LEN_SIZE 2
 #define DEFAULT_SEQ_NO_SIZE 4
-#define DEFAULT_TTL_SIZE 1
-#define DEFAULT_CHK_SIZE 2
 #define DEFAULT_MIN_PDU_SIZE 0
 #define DEFAULT_MAX_PDU_SIZE 9000
 #define DEFAULT_DDNS 0
@@ -62,8 +60,8 @@ static void usage()
                "                [cep_id <CEP-id size> (default: %d)]\n"
                "                [pdu_len <PDU length size> (default: %d)]\n"
                "                [seqno <sequence number size> (default: %d)]\n"
-               "                [ttl <time to live size>  (default: %d)]\n"
-               "                [chk <checksum size>  (default: %d)]\n"
+               "                [ttl <add time to live value in the PCI>]\n"
+               "                [chk <add 32-bit checksum in the PCI>]\n"
                "                [min_pdu <minimum PDU size> (default: %d)]\n"
                "                [max_pdu <maximum PDU size> (default: %d)]\n"
                "if TYPE == " SHIM_UDP "\n"
@@ -74,7 +72,6 @@ static void usage()
                "                if_name <interface name>\n",
                DEFAULT_ADDR_SIZE, DEFAULT_CEP_ID_SIZE,
                DEFAULT_PDU_LEN_SIZE, DEFAULT_SEQ_NO_SIZE,
-               DEFAULT_TTL_SIZE, DEFAULT_CHK_SIZE,
                DEFAULT_MIN_PDU_SIZE, DEFAULT_MAX_PDU_SIZE, DEFAULT_DDNS);
 }
 
@@ -86,8 +83,8 @@ int do_bootstrap_ipcp(int argc, char ** argv)
         uint8_t cep_id_size = DEFAULT_CEP_ID_SIZE;
         uint8_t pdu_length_size = DEFAULT_PDU_LEN_SIZE;
         uint8_t seqno_size = DEFAULT_SEQ_NO_SIZE;
-        uint8_t ttl_size = DEFAULT_TTL_SIZE;
-        uint8_t chk_size = DEFAULT_CHK_SIZE;
+        bool has_ttl = false;
+        bool has_chk = false;
         uint32_t min_pdu_size = DEFAULT_MIN_PDU_SIZE;
         uint32_t max_pdu_size = DEFAULT_MAX_PDU_SIZE;
         uint32_t ip_addr = 0;
@@ -112,7 +109,7 @@ int do_bootstrap_ipcp(int argc, char ** argv)
                                 return -1;
                         }
                 } else if (matches(*argv, "dns") == 0) {
-                        if (inet_pton (AF_INET, *(argv + 1), &dns_addr) != 1) {
+                        if (inet_pton(AF_INET, *(argv + 1), &dns_addr) != 1) {
                                 usage();
                                 return -1;
                         }
@@ -127,9 +124,13 @@ int do_bootstrap_ipcp(int argc, char ** argv)
                 } else if (matches(*argv, "seqno") == 0) {
                         seqno_size = atoi(*(argv + 1));
                 } else if (matches(*argv, "ttl") == 0) {
-                        ttl_size = atoi(*(argv + 1));
+                        has_ttl = true;
+                        argc++;
+                        argv--;
                 } else if (matches(*argv, "chk") == 0) {
-                        chk_size = atoi(*(argv + 1));
+                        has_chk = true;
+                        argc++;
+                        argv--;
                 } else if (matches(*argv, "min_pdu") == 0) {
                         min_pdu_size = atoi(*(argv + 1));
                 } else if (matches(*argv, "max_pdu") == 0) {
@@ -157,8 +158,8 @@ int do_bootstrap_ipcp(int argc, char ** argv)
                 conf.cep_id_size = cep_id_size;
                 conf.pdu_length_size = pdu_length_size;
                 conf.seqno_size = seqno_size;
-                conf.ttl_size = ttl_size;
-                conf.chk_size = chk_size;
+                conf.has_ttl = has_ttl;
+                conf.has_chk = has_chk;
                 conf.min_pdu_size = min_pdu_size;
                 conf.max_pdu_size = max_pdu_size;
         } else if (strcmp(ipcp_type, SHIM_UDP) == 0) {