feat: Add allow_custom_from_hostname config option to control custom From header hostname

README.md

@@ -62,6 +62,7 @@ prometheus_port: port used to collect prometheus metrics. Used for autoscaling
 log_level: debug, info, warn, or error (default info)
 sip_port: port to listen and send SIP traffic (default 5060)
 rtp_port: port to listen and send RTP traffic (default 10000-20000)
+allow_custom_from_hostname: if true, allows the From header to be set to a custom hostname retrieved from the outbound trunk (default false)
 ```
 
 The config file can be added to a mounted volume with its location passed in the SIP_CONFIG_FILE env var, or its body can be passed in the SIP_CONFIG_BODY env var.

pkg/config/config.go

@@ -124,6 +124,9 @@ type Config struct {
 		// InboundWaitACK forces SIP to wait for an ACK to 200 OK before proceeding with the call.
 		InboundWaitACK bool `yaml:"inbound_wait_ack"`
 	} `yaml:"experimental"`
+
+	// AllowCustomFromHostname allows the FROM header to be set to a custom hostname.
+	AllowCustomFromHostname bool `yaml:"allow_custom_from_hostname"`
 }
 
 func NewConfig(confString string) (*Config, error) {

pkg/sip/client.go

@@ -172,6 +172,9 @@
 }
 
 func (c *Client) createSIPParticipant(ctx context.Context, req *rpc.InternalCreateSIPParticipantRequest) (resp *rpc.InternalCreateSIPParticipantResponse, retErr error) {
+	if c.conf.AllowCustomFromHostname {
+		req.Hostname = req.FromHostname
+	}
 	if c.mon.Health() != stats.HealthOK {
 		return nil, siperrors.ErrUnavailable
 	}

pkg/sip/outbound_test.go

@@ -123,3 +123,85 @@
 
 	cancel()
 }
+func TestCreateSIPParticipant_CustomFromHostname(t *testing.T) {
+	t.Run("when allowCustomFromHostname is false", func(t *testing.T) {
+		customFromHost := "custom-from.example.com"
+
+		client := NewOutboundTestClient(t, TestClientConfig{})
+		client.conf.AllowCustomFromHostname = false
+
+		req := MinimalCreateSIPParticipantRequest()
+		req.FromHostname = customFromHost
+
+		ctx, cancel := context.WithCancel(context.Background())
+		defer cancel()
+		go func() {
+			_, _ = client.CreateSIPParticipant(ctx, req)
+		}()
+
+		var sipClient *testSIPClient
+		select {
+		case sipClient = <-createdClients:
+			t.Cleanup(func() { _ = sipClient.Close() })
+		case <-time.After(100 * time.Millisecond):
+			require.Fail(t, "expected client to be created")
+			return
+		}
+
+		var tr *transactionRequest
+		select {
+		case tr = <-sipClient.transactions:
+			t.Cleanup(func() { tr.transaction.Terminate() })
+		case <-time.After(500 * time.Millisecond):
+			require.Fail(t, "expected transaction request to be created")
+			return
+		}
+
+		require.NotNil(t, tr)
+		require.NotNil(t, tr.req)
+		require.NotNil(t, tr.req.From())
+		require.NotEqual(t, customFromHost, tr.req.From().Address.Host)
+
+		require.NoError(t, tr.transaction.SendResponse(sip.NewResponseFromRequest(tr.req, sip.StatusBusyHere, "Busy Here", nil)))
+	})
+
+	t.Run("when allowCustomFromHostname is true", func(t *testing.T) {
+		customFromHost := "custom-from.example.com"
+
+		client := NewOutboundTestClient(t, TestClientConfig{})
+		client.conf.AllowCustomFromHostname = true
+
+		req := MinimalCreateSIPParticipantRequest()
+		req.FromHostname = customFromHost
+
+		ctx, cancel := context.WithCancel(context.Background())
+		defer cancel()
+		go func() {
+			_, _ = client.CreateSIPParticipant(ctx, req)
+		}()
+
+		var sipClient *testSIPClient
+		select {
+		case sipClient = <-createdClients:
+			t.Cleanup(func() { _ = sipClient.Close() })
+		case <-time.After(100 * time.Millisecond):
+			require.Fail(t, "expected client to be created")
+			return
+		}
+
+		var tr *transactionRequest
+		select {
+		case tr = <-sipClient.transactions:
+			t.Cleanup(func() { tr.transaction.Terminate() })
+		case <-time.After(500 * time.Millisecond):
+			require.Fail(t, "expected transaction request to be created")
+			return
+		}
+
+		require.NotNil(t, tr)
+		require.NotNil(t, tr.req)
+		require.NotNil(t, tr.req.From())
+		require.Equal(t, customFromHost, tr.req.From().Address.Host)
+		require.NoError(t, tr.transaction.SendResponse(sip.NewResponseFromRequest(tr.req, sip.StatusBusyHere, "Busy Here", nil)))
+	})
+}