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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 It's only real substance is to perform an extremely outdated BSD4.2 ICMP check, which we can safely remove.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>
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parent
97bab73f98
commit
46517008e1
4 changed files with 1 additions and 70 deletions
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@ -215,8 +215,6 @@ static inline int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 s
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return ip_route_input_common(skb, dst, src, tos, devin, true);
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}
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extern unsigned short ip_rt_frag_needed(struct net *net, const struct iphdr *iph,
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unsigned short new_mtu, struct net_device *dev);
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extern void ip_rt_send_redirect(struct sk_buff *skb);
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extern unsigned int inet_addr_type(struct net *net, __be32 addr);
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@ -673,9 +673,7 @@ static void icmp_unreach(struct sk_buff *skb)
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LIMIT_NETDEBUG(KERN_INFO pr_fmt("%pI4: fragmentation needed and DF set\n"),
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&iph->daddr);
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} else {
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info = ip_rt_frag_needed(net, iph,
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ntohs(icmph->un.frag.mtu),
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skb->dev);
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info = ntohs(icmph->un.frag.mtu);
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if (!info)
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goto out;
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}
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@ -1664,67 +1664,6 @@ out: kfree_skb(skb);
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return 0;
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}
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/*
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* The last two values are not from the RFC but
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* are needed for AMPRnet AX.25 paths.
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*/
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static const unsigned short mtu_plateau[] =
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{32000, 17914, 8166, 4352, 2002, 1492, 576, 296, 216, 128 };
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static inline unsigned short guess_mtu(unsigned short old_mtu)
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{
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int i;
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for (i = 0; i < ARRAY_SIZE(mtu_plateau); i++)
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if (old_mtu > mtu_plateau[i])
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return mtu_plateau[i];
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return 68;
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}
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unsigned short ip_rt_frag_needed(struct net *net, const struct iphdr *iph,
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unsigned short new_mtu,
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struct net_device *dev)
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{
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unsigned short old_mtu = ntohs(iph->tot_len);
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unsigned short est_mtu = 0;
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struct inet_peer *peer;
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peer = inet_getpeer_v4(net->ipv4.peers, iph->daddr, 1);
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if (peer) {
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unsigned short mtu = new_mtu;
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if (new_mtu < 68 || new_mtu >= old_mtu) {
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/* BSD 4.2 derived systems incorrectly adjust
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* tot_len by the IP header length, and report
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* a zero MTU in the ICMP message.
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*/
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if (mtu == 0 &&
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old_mtu >= 68 + (iph->ihl << 2))
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old_mtu -= iph->ihl << 2;
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mtu = guess_mtu(old_mtu);
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}
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if (mtu < ip_rt_min_pmtu)
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mtu = ip_rt_min_pmtu;
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if (!peer->pmtu_expires || mtu < peer->pmtu_learned) {
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unsigned long pmtu_expires;
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pmtu_expires = jiffies + ip_rt_mtu_expires;
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if (!pmtu_expires)
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pmtu_expires = 1UL;
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est_mtu = mtu;
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peer->pmtu_learned = mtu;
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peer->pmtu_expires = pmtu_expires;
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atomic_inc(&__rt_peer_genid);
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}
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inet_putpeer(peer);
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}
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return est_mtu ? : new_mtu;
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}
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static void check_peer_pmtu(struct dst_entry *dst, struct inet_peer *peer)
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{
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unsigned long expires = ACCESS_ONCE(peer->pmtu_expires);
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@ -81,10 +81,6 @@ void rxrpc_UDP_error_report(struct sock *sk)
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_net("I/F MTU %u", mtu);
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}
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/* ip_rt_frag_needed() may have eaten the info */
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if (mtu == 0)
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mtu = ntohs(icmp_hdr(skb)->un.frag.mtu);
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if (mtu == 0) {
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/* they didn't give us a size, estimate one */
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if (mtu > 1500) {
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