4 files changed, 65 insertions, 0 deletions
diff --git a/protocol/handshake.go b/protocol/handshake.go
new file mode 100644
index 0000000..02e3f0d
--- /dev/null
+++ b/protocol/handshake.go
@@ -0,0 +1,14 @@
+package protocol
+
+const (
+	TokenHeader      = "X-Observatory-Token"
+	ObserverIDHeader = "X-Observatory-Observer-ID"
+)
+
+// ServerPushInfo is the first server->client packet, applying configs to observers
+type ServerPushInfo struct {
+	Version uint64   `json:"server_push_info_version"`
+	Targets []Target `json:"targets"`
+}
+
+const CurrentServerPushInfoVersion uint64 = 240308
diff --git a/protocol/messages.go b/protocol/messages.go
new file mode 100644
index 0000000..d8f5697
--- /dev/null
+++ b/protocol/messages.go
@@ -0,0 +1,29 @@
+package protocol
+
+import (
+	"encoding/json"
+	"time"
+)
+
+type TimeStamp time.Time
+
+func (t *TimeStamp) UnmarshalJSON(data []byte) error {
+	var ts int64
+	err := json.Unmarshal(data, &ts)
+	if err != nil {
+		return err
+	}
+	*t = TimeStamp(time.UnixMilli(ts))
+	return nil
+}
+
+func (t TimeStamp) MarshalJSON() ([]byte, error) {
+	return json.Marshal(time.Time(t).UnixMilli())
+}
+
+type Observation struct {
+	Time    TimeStamp `json:"time"`
+	Target  Target    `json:"target"`
+	Online  bool      `json:"online"`
+	Latency uint32    `json:"latency"`
+}
diff --git a/protocol/observe.go b/protocol/observe.go
new file mode 100644
index 0000000..48d052a
--- /dev/null
+++ b/protocol/observe.go
@@ -0,0 +1,14 @@
+package protocol
+
+import (
+	"fmt"
+)
+
+type Target struct {
+	Host string `json:"host"`
+	Port uint16 `json:"port"`
+}
+
+func (t Target) String() string {
+	return fmt.Sprintf("%s:%d", t.Host, t.Port)
+}
diff --git a/protocol/publish.go b/protocol/publish.go
new file mode 100644
index 0000000..13e6ee1
--- /dev/null
+++ b/protocol/publish.go
@@ -0,0 +1,8 @@
+package protocol
+
+type TargetStats map[string][]SourcedObservation
+
+type SourcedObservation struct {
+	Observation
+	Source string `json:"source,omitempty"`
+}