--- a/src/event/quic/ngx_event_quic_migration.c
+++ b/src/event/quic/ngx_event_quic_migration.c
@@ -24,8 +24,6 @@ ngx_int_t
 ngx_quic_handle_path_challenge_frame(ngx_connection_t *c,
     ngx_quic_path_challenge_frame_t *f)
 {
-    off_t                   max, pad;
-    ssize_t                 sent;
     ngx_quic_path_t        *path;
     ngx_quic_frame_t        frame, *fp;
     ngx_quic_socket_t      *qsock;
@@ -49,26 +47,11 @@ ngx_quic_handle_path_challenge_frame(ngx
     /*
      * An endpoint MUST expand datagrams that contain a PATH_RESPONSE frame
      * to at least the smallest allowed maximum datagram size of 1200 bytes.
-     * ...
-     * An endpoint MUST NOT expand the datagram containing the PATH_RESPONSE
-     * if the resulting data exceeds the anti-amplification limit.
      */
-    if (path->state != NGX_QUIC_PATH_VALIDATED) {
-        max = path->received * 3;
-        max = (path->sent >= max) ? 0 : max - path->sent;
-        pad = ngx_min(1200, max);
-
-    } else {
-        pad = 1200;
-    }
-
-    sent = ngx_quic_frame_sendto(c, &frame, pad, path->sockaddr, path->socklen);
-    if (sent < 0) {
+    if (ngx_quic_frame_sendto(c, &frame, 1200, path) != NGX_OK) {
         return NGX_ERROR;
     }
 
-    path->sent += sent;
-
     if (qsock == qc->socket) {
         /*
          * RFC 9000, 9.3.3.  Off-Path Packet Forwarding
@@ -535,8 +518,6 @@ ngx_quic_validate_path(ngx_connection_t 
 static ngx_int_t
 ngx_quic_send_path_challenge(ngx_connection_t *c, ngx_quic_path_t *path)
 {
-    off_t             max, pad;
-    ssize_t           sent;
     ngx_quic_frame_t  frame;
 
     ngx_log_debug2(NGX_LOG_DEBUG_EVENT, c->log, 0,
@@ -558,30 +539,16 @@ ngx_quic_send_path_challenge(ngx_connect
      */
 
      /* same applies to PATH_RESPONSE frames */
-
-    max = path->received * 3;
-    max = (path->sent >= max) ? 0 : max - path->sent;
-    pad = ngx_min(1200, max);
-
-    sent = ngx_quic_frame_sendto(c, &frame, pad, path->sockaddr, path->socklen);
-    if (sent < 0) {
+    if (ngx_quic_frame_sendto(c, &frame, 1200, path) != NGX_OK) {
         return NGX_ERROR;
     }
 
-    path->sent += sent;
-
     ngx_memcpy(frame.u.path_challenge.data, path->challenge2, 8);
 
-    max = (path->sent >= max) ? 0 : max - path->sent;
-    pad = ngx_min(1200, max);
-
-    sent = ngx_quic_frame_sendto(c, &frame, pad, path->sockaddr, path->socklen);
-    if (sent < 0) {
+    if (ngx_quic_frame_sendto(c, &frame, 1200, path) != NGX_OK) {
         return NGX_ERROR;
     }
 
-    path->sent += sent;
-
     return NGX_OK;
 }
 

--- a/src/event/quic/ngx_event_quic_output.c
+++ b/src/event/quic/ngx_event_quic_output.c
@@ -1208,12 +1208,13 @@ ngx_quic_send_ack_range(ngx_connection_t
 }
 
 
-ssize_t
+ngx_int_t
 ngx_quic_frame_sendto(ngx_connection_t *c, ngx_quic_frame_t *frame,
-    size_t min, struct sockaddr *sockaddr, socklen_t socklen)
+    size_t min, ngx_quic_path_t *path)
 {
+    off_t                   max;
     size_t                  min_payload, pad;
-    ssize_t                 len;
+    ssize_t                 len, sent;
     ngx_str_t               res;
     ngx_quic_header_t       pkt;
     ngx_quic_send_ctx_t    *ctx;
@@ -1227,6 +1228,15 @@ ngx_quic_frame_sendto(ngx_connection_t *
 
     ngx_quic_init_packet(c, ctx, qc->socket, &pkt);
 
+    /* account for anti-amplification limit: expand to allowed size */
+    if (path->state != NGX_QUIC_PATH_VALIDATED) {
+        max = path->received * 3;
+        max = (path->sent >= max) ? 0 : max - path->sent;
+        if ((off_t) min > max) {
+            min = max;
+        }
+    }
+
     min_payload = min ? ngx_quic_payload_size(&pkt, min) : 0;
 
     pad = 4 - pkt.num_len;
@@ -1234,14 +1244,14 @@ ngx_quic_frame_sendto(ngx_connection_t *
 
     len = ngx_quic_create_frame(NULL, frame);
     if (len > NGX_QUIC_MAX_UDP_PAYLOAD_SIZE) {
-        return -1;
+        return NGX_ERROR;
     }
 
     ngx_quic_log_frame(c->log, frame, 1);
 
     len = ngx_quic_create_frame(src, frame);
     if (len == -1) {
-        return -1;
+        return NGX_ERROR;
     }
 
     if (len < (ssize_t) min_payload) {
@@ -1255,10 +1265,17 @@ ngx_quic_frame_sendto(ngx_connection_t *
     res.data = dst;
 
     if (ngx_quic_encrypt(&pkt, &res) != NGX_OK) {
-        return -1;
+        return NGX_ERROR;
     }
 
     ctx->pnum++;
 
-    return ngx_quic_send(c, res.data, res.len, sockaddr, socklen);
+    sent = ngx_quic_send(c, res.data, res.len, path->sockaddr, path->socklen);
+    if (sent < 0) {
+        return NGX_ERROR;
+    }
+
+    path->sent += sent;
+
+    return NGX_OK;
 }

--- a/src/event/quic/ngx_event_quic_output.h
+++ b/src/event/quic/ngx_event_quic_output.h
@@ -34,7 +34,7 @@ ngx_int_t ngx_quic_send_ack(ngx_connecti
 ngx_int_t ngx_quic_send_ack_range(ngx_connection_t *c,
     ngx_quic_send_ctx_t *ctx, uint64_t smallest, uint64_t largest);
 
-ssize_t ngx_quic_frame_sendto(ngx_connection_t *c, ngx_quic_frame_t *frame,
-    size_t min, struct sockaddr *sockaddr, socklen_t socklen);
+ngx_int_t ngx_quic_frame_sendto(ngx_connection_t *c, ngx_quic_frame_t *frame,
+    size_t min, ngx_quic_path_t *path);
 
 #endif /* _NGX_EVENT_QUIC_OUTPUT_H_INCLUDED_ */