ipv4: Kill ip_rt_frag_needed().
There is zero point to this function.
It's only real substance is to perform an extremely outdated BSD4.2
ICMP check, which we can safely remove. If you really have a MTU
limited link being routed by a BSD4.2 derived system, here's a nickel
go buy yourself a real router.
The other actions of ip_rt_frag_needed(), checking and conditionally
updating the peer, are done by the per-protocol handlers of the ICMP
event.
TCP, UDP, et al. have a handler which will receive this event and
transmit it back into the associated route via dst_ops->update_pmtu().
This simplification is important, because it eliminates the one place
where we do not have a proper route context in which to make an
inetpeer lookup.
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 0c78ef1..e1caa1a 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -673,9 +673,7 @@
LIMIT_NETDEBUG(KERN_INFO pr_fmt("%pI4: fragmentation needed and DF set\n"),
&iph->daddr);
} else {
- info = ip_rt_frag_needed(net, iph,
- ntohs(icmph->un.frag.mtu),
- skb->dev);
+ info = ntohs(icmph->un.frag.mtu);
if (!info)
goto out;
}
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 03e5b61..4f5834c 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1664,67 +1664,6 @@
return 0;
}
-/*
- * The last two values are not from the RFC but
- * are needed for AMPRnet AX.25 paths.
- */
-
-static const unsigned short mtu_plateau[] =
-{32000, 17914, 8166, 4352, 2002, 1492, 576, 296, 216, 128 };
-
-static inline unsigned short guess_mtu(unsigned short old_mtu)
-{
- int i;
-
- for (i = 0; i < ARRAY_SIZE(mtu_plateau); i++)
- if (old_mtu > mtu_plateau[i])
- return mtu_plateau[i];
- return 68;
-}
-
-unsigned short ip_rt_frag_needed(struct net *net, const struct iphdr *iph,
- unsigned short new_mtu,
- struct net_device *dev)
-{
- unsigned short old_mtu = ntohs(iph->tot_len);
- unsigned short est_mtu = 0;
- struct inet_peer *peer;
-
- peer = inet_getpeer_v4(net->ipv4.peers, iph->daddr, 1);
- if (peer) {
- unsigned short mtu = new_mtu;
-
- if (new_mtu < 68 || new_mtu >= old_mtu) {
- /* BSD 4.2 derived systems incorrectly adjust
- * tot_len by the IP header length, and report
- * a zero MTU in the ICMP message.
- */
- if (mtu == 0 &&
- old_mtu >= 68 + (iph->ihl << 2))
- old_mtu -= iph->ihl << 2;
- mtu = guess_mtu(old_mtu);
- }
-
- if (mtu < ip_rt_min_pmtu)
- mtu = ip_rt_min_pmtu;
- if (!peer->pmtu_expires || mtu < peer->pmtu_learned) {
- unsigned long pmtu_expires;
-
- pmtu_expires = jiffies + ip_rt_mtu_expires;
- if (!pmtu_expires)
- pmtu_expires = 1UL;
-
- est_mtu = mtu;
- peer->pmtu_learned = mtu;
- peer->pmtu_expires = pmtu_expires;
- atomic_inc(&__rt_peer_genid);
- }
-
- inet_putpeer(peer);
- }
- return est_mtu ? : new_mtu;
-}
-
static void check_peer_pmtu(struct dst_entry *dst, struct inet_peer *peer)
{
unsigned long expires = ACCESS_ONCE(peer->pmtu_expires);
diff --git a/net/rxrpc/ar-error.c b/net/rxrpc/ar-error.c
index 5d6b572..a920608 100644
--- a/net/rxrpc/ar-error.c
+++ b/net/rxrpc/ar-error.c
@@ -81,10 +81,6 @@
_net("I/F MTU %u", mtu);
}
- /* ip_rt_frag_needed() may have eaten the info */
- if (mtu == 0)
- mtu = ntohs(icmp_hdr(skb)->un.frag.mtu);
-
if (mtu == 0) {
/* they didn't give us a size, estimate one */
if (mtu > 1500) {