mirrors/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2025-11-04 02:30:34 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions

ipv4: Kill ip_rt_frag_needed().

Browse source 
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It's only real substance is to perform an extremely outdated BSD4.2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>
This commit is contained in:
David S. Miller 2012-06-10 00:04:12 -07:00
parent 97bab73f98
commit 46517008e1
4 changed files with 1 additions and 70 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

2
include/net/route.h
View file

@ -215,8 +215,6 @@ static inline int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 s
return ip_route_input_common(skb, dst, src, tos, devin, true);
}
extern unsigned short ip_rt_frag_needed(struct net *net, const struct iphdr *iph,
unsigned short new_mtu, struct net_device *dev);
extern void ip_rt_send_redirect(struct sk_buff *skb);
extern unsigned int inet_addr_type(struct net *net, __be32 addr);

4
net/ipv4/icmp.c
View file

@ -673,9 +673,7 @@ static void icmp_unreach(struct sk_buff *skb)
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;
}

61
net/ipv4/route.c
View file

@ -1664,67 +1664,6 @@ out: kfree_skb(skb);
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);

4
net/rxrpc/ar-error.c
View file

@ -81,10 +81,6 @@ void rxrpc_UDP_error_report(struct sock *sk)
_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) {