Added protobuf definitions for bitswap

Source:
https://github.com/ipfs/go-bitswap/blob/master/message/pb/message.proto

ipfs/protobuf/message.proto

@@ -0,0 +1,46 @@
+syntax = "proto3";
+
+package bitswap.message.pb;
+
+import "github.com/gogo/protobuf/gogoproto/gogo.proto";
+
+message Message {
+
+  message Wantlist {
+    enum WantType {
+      Block = 0;
+      Have = 1;
+    }
+
+    message Entry {
+			bytes block = 1 [(gogoproto.customtype) = "Cid", (gogoproto.nullable) = false];		// the block cid (cidV0 in bitswap 1.0.0, cidV1 in bitswap 1.1.0)
+			int32 priority = 2;	// the priority (normalized). default to 1
+			bool cancel = 3;		// whether this revokes an entry
+      WantType wantType = 4; // Note: defaults to enum 0, ie Block
+      bool sendDontHave = 5; // Note: defaults to false
+		}
+
+    repeated Entry entries = 1 [(gogoproto.nullable) = false];	// a list of wantlist entries
+    bool full = 2;							// whether this is the full wantlist. default to false
+  }
+
+  message Block {
+    bytes prefix = 1;		// CID prefix (cid version, multicodec and multihash prefix (type + length)
+    bytes data = 2;
+  }
+
+  enum BlockPresenceType {
+    Have = 0;
+    DontHave = 1;
+  }
+  message BlockPresence {
+    bytes cid = 1 [(gogoproto.customtype) = "Cid", (gogoproto.nullable) = false];
+    BlockPresenceType type = 2;
+  }
+
+  Wantlist wantlist = 1 [(gogoproto.nullable) = false];
+  repeated bytes blocks = 2;		// used to send Blocks in bitswap 1.0.0
+  repeated Block payload = 3 [(gogoproto.nullable) = false];		// used to send Blocks in bitswap 1.1.0
+  repeated BlockPresence blockPresences = 4 [(gogoproto.nullable) = false];
+  int32 pendingBytes = 5;
+}

ipfs/protobuf/message.proto.license

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+The MIT License (MIT)
+
+Copyright (c) 2014-2018 Juan Batiz-Benet
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.