net: introduce packet as data_source adapter

net/packet-data-source.hh

@@ -0,0 +1,35 @@
+#ifndef _PACKET_DATA_SOURCE_HH
+#define _PACKET_DATA_SOURCE_HH
+
+#include "core/reactor.hh"
+#include "net/packet.hh"
+
+namespace net {
+
+class packet_data_source final : public data_source_impl {
+    size_t _cur_frag = 0;
+    packet _p;
+public:
+    explicit packet_data_source(net::packet&& p)
+        : _p(std::move(p))
+    {}
+
+    virtual future<temporary_buffer<char>> get() override {
+        if (_cur_frag != _p.nr_frags()) {
+            auto& f = _p.fragments()[_cur_frag++];
+            return make_ready_future<temporary_buffer<char>>(
+                    temporary_buffer<char>(f.base, f.size,
+                            make_deleter(deleter(), [p = _p.share()] () mutable {})));
+        }
+        return make_ready_future<temporary_buffer<char>>(temporary_buffer<char>(0));
+    }
+};
+
+static inline
+input_stream<char> as_input_stream(packet&& p) {
+    return input_stream<char>(data_source(std::make_unique<packet_data_source>(std::move(p))));
+}
+
+}
+
+#endif