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ad52eef552
[ Upstream commit 73f156a6e8 ]
Ideally, we would need to generate IP ID using a per destination IP
generator.
linux kernels used inet_peer cache for this purpose, but this had a huge
cost on servers disabling MTU discovery.
1) each inet_peer struct consumes 192 bytes
2) inetpeer cache uses a binary tree of inet_peer structs,
with a nominal size of ~66000 elements under load.
3) lookups in this tree are hitting a lot of cache lines, as tree depth
is about 20.
4) If server deals with many tcp flows, we have a high probability of
not finding the inet_peer, allocating a fresh one, inserting it in
the tree with same initial ip_id_count, (cf secure_ip_id())
5) We garbage collect inet_peer aggressively.
IP ID generation do not have to be 'perfect'
Goal is trying to avoid duplicates in a short period of time,
so that reassembly units have a chance to complete reassembly of
fragments belonging to one message before receiving other fragments
with a recycled ID.
We simply use an array of generators, and a Jenkin hash using the dst IP
as a key.
ipv6_select_ident() is put back into net/ipv6/ip6_output.c where it
belongs (it is only used from this file)
secure_ip_id() and secure_ipv6_id() no longer are needed.
Rename ip_select_ident_more() to ip_select_ident_segs() to avoid
unnecessary decrement/increment of the number of segments.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
67 lines
1.6 KiB
C
67 lines
1.6 KiB
C
#ifndef __NET_IPIP_H
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#define __NET_IPIP_H 1
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#include <linux/if_tunnel.h>
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#include <net/ip.h>
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/* Keep error state on tunnel for 30 sec */
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#define IPTUNNEL_ERR_TIMEO (30*HZ)
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/* 6rd prefix/relay information */
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struct ip_tunnel_6rd_parm {
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struct in6_addr prefix;
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__be32 relay_prefix;
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u16 prefixlen;
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u16 relay_prefixlen;
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};
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struct ip_tunnel {
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struct ip_tunnel __rcu *next;
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struct net_device *dev;
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int err_count; /* Number of arrived ICMP errors */
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unsigned long err_time; /* Time when the last ICMP error arrived */
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/* These four fields used only by GRE */
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__u32 i_seqno; /* The last seen seqno */
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__u32 o_seqno; /* The last output seqno */
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int hlen; /* Precalculated GRE header length */
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int mlink;
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struct ip_tunnel_parm parms;
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/* for SIT */
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#ifdef CONFIG_IPV6_SIT_6RD
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struct ip_tunnel_6rd_parm ip6rd;
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#endif
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struct ip_tunnel_prl_entry __rcu *prl; /* potential router list */
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unsigned int prl_count; /* # of entries in PRL */
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};
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struct ip_tunnel_prl_entry {
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struct ip_tunnel_prl_entry __rcu *next;
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__be32 addr;
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u16 flags;
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struct rcu_head rcu_head;
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};
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#define __IPTUNNEL_XMIT(stats1, stats2) do { \
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int err; \
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int pkt_len = skb->len - skb_transport_offset(skb); \
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\
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skb->ip_summed = CHECKSUM_NONE; \
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ip_select_ident(skb, NULL); \
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\
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err = ip_local_out(skb); \
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if (likely(net_xmit_eval(err) == 0)) { \
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(stats1)->tx_bytes += pkt_len; \
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(stats1)->tx_packets++; \
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} else { \
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(stats2)->tx_errors++; \
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(stats2)->tx_aborted_errors++; \
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} \
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} while (0)
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#define IPTUNNEL_XMIT() __IPTUNNEL_XMIT(txq, stats)
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#endif
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