From d976092ce1b04d634d408f475224347cfae81201 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Fri, 23 Apr 2021 11:17:06 -0700 Subject: [PATCH] mptcp: implement MSG_TRUNC support The mentioned flag is currently silenlty ignored. This change implements the TCP-like behaviour, dropping the pending data up to the specified length. Signed-off-by: Paolo Abeni Sigend-off-by: Mat Martineau Signed-off-by: David S. Miller --- net/mptcp/protocol.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 1d5f23bd640c..ae08c563c712 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1739,7 +1739,7 @@ static void mptcp_wait_data(struct sock *sk, long *timeo) static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk, struct msghdr *msg, - size_t len) + size_t len, int flags) { struct sk_buff *skb; int copied = 0; @@ -1750,11 +1750,13 @@ static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk, u32 count = min_t(size_t, len - copied, data_len); int err; - err = skb_copy_datagram_msg(skb, offset, msg, count); - if (unlikely(err < 0)) { - if (!copied) - return err; - break; + if (!(flags & MSG_TRUNC)) { + err = skb_copy_datagram_msg(skb, offset, msg, count); + if (unlikely(err < 0)) { + if (!copied) + return err; + break; + } } copied += count; @@ -1966,7 +1968,7 @@ static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, while (copied < len) { int bytes_read; - bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied); + bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied, flags); if (unlikely(bytes_read < 0)) { if (!copied) copied = bytes_read;