netdev - [PATCH] net: ipv4: Remove MTU check in IP

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Date:   Sun, 7 Jan 2018 01:26:48 +0200
From:   Yonatan Goldschmidt <dev.jongy@...il.com>
To:     netdev@...r.kernel.org
Cc:     "David S. Miller" <davem@...emloft.net>
Subject: [PATCH] net: ipv4: Remove MTU check in IP_HDRINCL send flow

IP fragmentation can be performed as expected down the stack, without touching
irrelevant fields in the included header besides fragment offset, setting
IP_MF and header checksum.
If the included header has IP_DF set, EMSGSIZE is returned.

This allows users of IP_HDRINCL to have the kernel perform fragmentation.

Signed-off-by: Yonatan Goldschmidt <dev.jongy@...il.com>
---
 net/ipv4/raw.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index 125c1eab3eaa..63167abff05b 100644
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -359,11 +359,6 @@ static int raw_send_hdrinc(struct sock *sk, struct
flowi*,
        struct rtable *rt = *rtp;
        int hlen, tlen;

-       if (length > rt->dst.dev->mtu) {
-               ip_local_error(sk, EMSGSIZE, fl4->daddr,
inet->inet_dport,
-                              rt->dst.dev->mtu);
-               return -EMSGSIZE;
-       }
        if (length < sizeof(struct iphdr))
                return -EINVAL;

--
2.15.1