From cb1a271c619821d7a6caff54e133202c0a9a693f Mon Sep 17 00:00:00 2001
From: goldsimon <goldsimon@gmx.de>
Date: Sat, 11 Mar 2017 20:42:59 +0100
Subject: [PATCH] lwip_recvmsg: MSG_PEEK must be limited to the first iov for
 TCP

---
 src/api/sockets.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/api/sockets.c b/src/api/sockets.c
index f5ba50d8..4abfb1b4 100644
--- a/src/api/sockets.c
+++ b/src/api/sockets.c
@@ -1144,8 +1144,9 @@ lwip_recvmsg(int s, struct msghdr *message, int flags)
         /* sum up received bytes */
         ret += recvd_local;
       }
-      if ((recvd_local < 0) || (recvd_local < (int)message->msg_iov[i].iov_len)) {
-        /* returned prematurely */
+      if ((recvd_local < 0) || (recvd_local < (int)message->msg_iov[i].iov_len) ||
+          (flags & MSG_PEEK)) {
+        /* returned prematurely (or peeking, which might actually be limitated to the first iov) */
         if (ret <= 0) {
           /* nothing received at all, propagate the error */
           ret = recvd_local;