h3: support trailer field sections

include/tquic.h

@@ -425,7 +425,7 @@ typedef struct quic_conn_stats_t {
 
 typedef struct http3_methods_t {
   /**
-   * Called when the stream got headers.
+   * Called when the stream receives a header or trailer field section.
    */
   void (*on_stream_headers)(void *ctx,
                             uint64_t stream_id,
@@ -1445,7 +1445,7 @@ int http3_stream_set_priority(struct http3_conn_t *conn,
                               const struct http3_priority_t *priority);
 
 /**
- * Send HTTP/3 request or response headers on the given stream.
+ * Send initial HTTP/3 request or response headers on the given stream.
  */
 int http3_send_headers(struct http3_conn_t *conn,
                        struct quic_conn_t *quic_conn,
@@ -1454,6 +1454,21 @@ int http3_send_headers(struct http3_conn_t *conn,
                        size_t headers_len,
                        bool fin);
 
+/**
+ * Send an additional HTTP/3 field section on the given stream.
+ *
+ * Clients can only send trailer sections. Servers can also send additional
+ * response field sections before the response body. Once a trailer section is
+ * sent, no more HEADERS or DATA frames can be sent on the stream.
+ */
+int http3_send_additional_headers(struct http3_conn_t *conn,
+                                  struct quic_conn_t *quic_conn,
+                                  uint64_t stream_id,
+                                  const struct http3_header_t *headers,
+                                  size_t headers_len,
+                                  bool is_trailer_section,
+                                  bool fin);
+
 /**
  * Send HTTP/3 request or response body on the given stream.
  */

src/ffi.rs

@@ -2349,7 +2349,7 @@ pub struct Header {
     value_len: usize,
 }
 
-/// Send HTTP/3 request or response headers on the given stream.
+/// Send initial HTTP/3 request or response headers on the given stream.
 #[cfg(feature = "h3")]
 #[no_mangle]
 pub extern "C" fn http3_send_headers(
@@ -2368,6 +2368,30 @@ pub extern "C" fn http3_send_headers(
     }
 }
 
+/// Send an additional HTTP/3 field section on the given stream.
+///
+/// Clients can only send trailer sections. Servers can also send additional
+/// response field sections before the response body. Once a trailer section is
+/// sent, no more HEADERS or DATA frames can be sent on the stream.
+#[cfg(feature = "h3")]
+#[no_mangle]
+pub extern "C" fn http3_send_additional_headers(
+    conn: &mut Http3Connection,
+    quic_conn: &mut Connection,
+    stream_id: u64,
+    headers: *const Header,
+    headers_len: size_t,
+    is_trailer_section: bool,
+    fin: bool,
+) -> c_int {
+    let h3_headers = headers_from_ptr(headers, headers_len);
+
+    match conn.send_additional_headers(quic_conn, stream_id, &h3_headers, is_trailer_section, fin) {
+        Ok(_) => 0,
+        Err(e) => e.to_errno() as c_int,
+    }
+}
+
 /// Send HTTP/3 request or response body on the given stream.
 #[cfg(feature = "h3")]
 #[no_mangle]
@@ -2516,7 +2540,7 @@ pub extern "C" fn quic_set_logger(
 #[cfg(feature = "h3")]
 #[repr(C)]
 pub struct Http3Methods {
-    /// Called when the stream got headers.
+    /// Called when the stream receives a header or trailer field section.
     pub on_stream_headers:
         Option<fn(ctx: *mut c_void, stream_id: u64, headers: &Http3Headers, fin: bool)>,