From ac6627a28dbfb5d96736544a00c3938fa7ea6dfb Mon Sep 17 00:00:00 2001 From: Vadim Fedorenko Date: Tue, 20 Jul 2021 23:06:28 +0300 Subject: [PATCH] net: ipv4: Consolidate ipv4_mtu and ip_dst_mtu_maybe_forward Consolidate IPv4 MTU code the same way it is done in IPv6 to have code aligned in both address families Signed-off-by: Vadim Fedorenko Reviewed-by: David Ahern Signed-off-by: David S. Miller --- include/net/ip.h | 22 ++++++++++++++++++---- net/ipv4/route.c | 21 +-------------------- 2 files changed, 19 insertions(+), 24 deletions(-) diff --git a/include/net/ip.h b/include/net/ip.h index d9683bef86840..9192444f2964e 100644 --- a/include/net/ip.h +++ b/include/net/ip.h @@ -436,18 +436,32 @@ static inline bool ip_sk_ignore_df(const struct sock *sk) static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst, bool forwarding) { + const struct rtable *rt = container_of(dst, struct rtable, dst); struct net *net = dev_net(dst->dev); unsigned int mtu; if (net->ipv4.sysctl_ip_fwd_use_pmtu || ip_mtu_locked(dst) || - !forwarding) - return dst_mtu(dst); + !forwarding) { + mtu = rt->rt_pmtu; + if (mtu && time_before(jiffies, rt->dst.expires)) + goto out; + } /* 'forwarding = true' case should always honour route mtu */ mtu = dst_metric_raw(dst, RTAX_MTU); - if (!mtu) - mtu = min(READ_ONCE(dst->dev->mtu), IP_MAX_MTU); + if (mtu) + goto out; + + mtu = READ_ONCE(dst->dev->mtu); + + if (unlikely(ip_mtu_locked(dst))) { + if (rt->rt_uses_gateway && mtu > 576) + mtu = 576; + } + +out: + mtu = min_t(unsigned int, mtu, IP_MAX_MTU); return mtu - lwtunnel_headroom(dst->lwtstate, mtu); } diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 99c06944501ab..04754d55b3c17 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -1299,26 +1299,7 @@ static unsigned int ipv4_default_advmss(const struct dst_entry *dst) INDIRECT_CALLABLE_SCOPE unsigned int ipv4_mtu(const struct dst_entry *dst) { - const struct rtable *rt = (const struct rtable *)dst; - unsigned int mtu = rt->rt_pmtu; - - if (!mtu || time_after_eq(jiffies, rt->dst.expires)) - mtu = dst_metric_raw(dst, RTAX_MTU); - - if (mtu) - goto out; - - mtu = READ_ONCE(dst->dev->mtu); - - if (unlikely(ip_mtu_locked(dst))) { - if (rt->rt_uses_gateway && mtu > 576) - mtu = 576; - } - -out: - mtu = min_t(unsigned int, mtu, IP_MAX_MTU); - - return mtu - lwtunnel_headroom(dst->lwtstate, mtu); + return ip_dst_mtu_maybe_forward(dst, false); } EXPORT_INDIRECT_CALLABLE(ipv4_mtu); -- 2.39.5