[PATCH 2/5] ipv4: Kill ip_rt_frag_needed().
From: David Miller <davem@davemloft.net>
Date: 2012-06-11 09:29:12
Subsystem:
networking [general], networking [ipv4/ipv6], rxrpc sockets (af_rxrpc), the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Ahern, Ido Schimmel, David Howells, Marc Dionne, Linus Torvalds
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 It's only real substance is to perform an extremely outdated BSD4.2 ICMP check, which we can safely remove.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> --- include/net/route.h | 2 -- net/ipv4/icmp.c | 4 +--- net/ipv4/route.c | 61 -------------------------------------------------- net/rxrpc/ar-error.c | 4 ---- 4 files changed, 1 insertion(+), 70 deletions(-)
diff --git a/include/net/route.h b/include/net/route.h
index 6340c37..cc693a5 100644
--- a/include/net/route.h
+++ b/include/net/route.h@@ -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);
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 @@ 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; }
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 @@ 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);
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 @@ 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) {
--
1.7.10