[HICN-39] Added api that return a pointer to the signature hold in a packet

[HICN-40] Fixed signature calculation by allocating a contiguous portion of
memory that holds the entire hICN header (IP+TCP+AH)

Change-Id: I9d40bab0e3ecb82949b8b3a00e2cc1214457e4e3
Signed-off-by: Alberto Compagno <acompagn+fdio@cisco.com>

2 files changed, 21 insertions, 11 deletions

diff --git a/libtransport/src/hicn/transport/core/packet.cc b/libtransport/src/hicn/transport/core/packet.cc
index dd150d723..3872510ec 100644
--- a/libtransport/src/hicn/transport/core/packet.cc
+++ b/libtransport/src/hicn/transport/core/packet.cc
@@ -32,7 +32,7 @@ namespace core {
 const core::Name Packet::base_name("0::0|0");
 
 Packet::Packet(Format format)
-    : packet_(utils::MemBuf::create(getHeaderSizeFromFormat(format)).release()),
+    : packet_(utils::MemBuf::create(getHeaderSizeFromFormat(format, 256)).release()),
       packet_start_(packet_->writableData()),
       header_head_(packet_.get()),
       payload_head_(nullptr),
@@ -50,28 +50,22 @@ Packet::Packet(MemBufPtr &&buffer)
       header_head_(packet_.get()),
       payload_head_(nullptr),
       format_(getFormatFromBuffer(packet_start_)) {
-  auto header_size = getHeaderSizeFromFormat(format_);
-  int signature_size = 0;
 
+  int signature_size = 0;
   if (_is_ah(format_)) {
     signature_size = getSignatureSize();
   }
 
+  auto header_size = getHeaderSizeFromFormat(format_, signature_size);
+
   auto payload_length = packet_->length() - header_size - signature_size;
 
-  if (!payload_length && !signature_size) {
+  if (!payload_length) {
     return;
   }
 
   packet_->trimEnd(packet_->length());
 
-  if (signature_size) {
-    auto sig = packet_->cloneOne();
-    sig->advance(header_size);
-    sig->append(signature_size);
-    packet_->appendChain(std::move(sig));
-  }
-
   if (payload_length) {
     auto payload = packet_->cloneOne();
     payload_head_ = payload.get();
@@ -285,6 +279,20 @@ void Packet::setSignatureSize(std::size_t size_bytes) {
   if (ret < 0) {
     throw errors::RuntimeException("Packet without Authentication Header.");
   }
+
+  packet_->append(size_bytes);
+}
+
+uint8_t * Packet::getSignature() const {
+  uint8_t * signature;
+  int ret = hicn_packet_get_signature(
+      format_, (hicn_header_t *)packet_start_, &signature);
+
+  if (ret < 0) {
+    throw errors::RuntimeException("Packet without Authentication Header.");
+  }
+
+  return signature;
 }
 
 std::size_t Packet::getSignatureSize() const {
diff --git a/libtransport/src/hicn/transport/core/packet.h b/libtransport/src/hicn/transport/core/packet.h
index bc23588dc..038676540 100644
--- a/libtransport/src/hicn/transport/core/packet.h
+++ b/libtransport/src/hicn/transport/core/packet.h
@@ -133,6 +133,8 @@ class Packet : public std::enable_shared_from_this<Packet> {
 
   std::size_t getSignatureSize() const;
 
+  uint8_t * getSignature() const;
+
   void setSignatureTimestamp(const uint64_t &timestamp);
 
   uint64_t getSignatureTimestamp() const;