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![Lorenzo Bianconi](/assets/img/avatar_default.png)
According to the algorithm described in the comment block at the
beginning of ip_rt_send_redirect, the host should try to send
'ip_rt_redirect_number' ICMP redirect packets with an exponential
backoff and then stop sending them at all assuming that the destination
ignores redirects.
If the device has previously sent some ICMP error packets that are
rate-limited (e.g TTL expired) and continues to receive traffic,
the redirect packets will never be transmitted. This happens since
peer->rate_tokens will be typically greater than 'ip_rt_redirect_number'
and so it will never be reset even if the redirect silence timeout
(ip_rt_redirect_silence) has elapsed without receiving any packet
requiring redirects.
Fix it by using a dedicated counter for the number of ICMP redirect
packets that has been sent by the host
I have not been able to identify a given commit that introduced the
issue since ip_rt_send_redirect implements the same rate-limiting
algorithm from commit 1da177e4c3
("Linux-2.6.12-rc2")
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
152 lines
3.3 KiB
C
152 lines
3.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* INETPEER - A storage for permanent information about peers
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*
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* Authors: Andrey V. Savochkin <saw@msu.ru>
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*/
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#ifndef _NET_INETPEER_H
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#define _NET_INETPEER_H
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#include <linux/types.h>
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#include <linux/init.h>
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#include <linux/jiffies.h>
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#include <linux/spinlock.h>
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#include <linux/rtnetlink.h>
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#include <net/ipv6.h>
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#include <linux/atomic.h>
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/* IPv4 address key for cache lookups */
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struct ipv4_addr_key {
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__be32 addr;
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int vif;
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};
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#define INETPEER_MAXKEYSZ (sizeof(struct in6_addr) / sizeof(u32))
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struct inetpeer_addr {
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union {
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struct ipv4_addr_key a4;
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struct in6_addr a6;
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u32 key[INETPEER_MAXKEYSZ];
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};
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__u16 family;
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};
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struct inet_peer {
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struct rb_node rb_node;
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struct inetpeer_addr daddr;
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u32 metrics[RTAX_MAX];
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u32 rate_tokens; /* rate limiting for ICMP */
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u32 n_redirects;
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unsigned long rate_last;
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/*
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* Once inet_peer is queued for deletion (refcnt == 0), following field
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* is not available: rid
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* We can share memory with rcu_head to help keep inet_peer small.
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*/
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union {
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struct {
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atomic_t rid; /* Frag reception counter */
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};
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struct rcu_head rcu;
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};
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/* following fields might be frequently dirtied */
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__u32 dtime; /* the time of last use of not referenced entries */
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refcount_t refcnt;
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};
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struct inet_peer_base {
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struct rb_root rb_root;
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seqlock_t lock;
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int total;
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};
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void inet_peer_base_init(struct inet_peer_base *);
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void inet_initpeers(void) __init;
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#define INETPEER_METRICS_NEW (~(u32) 0)
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static inline void inetpeer_set_addr_v4(struct inetpeer_addr *iaddr, __be32 ip)
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{
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iaddr->a4.addr = ip;
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iaddr->a4.vif = 0;
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iaddr->family = AF_INET;
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}
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static inline __be32 inetpeer_get_addr_v4(struct inetpeer_addr *iaddr)
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{
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return iaddr->a4.addr;
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}
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static inline void inetpeer_set_addr_v6(struct inetpeer_addr *iaddr,
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struct in6_addr *in6)
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{
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iaddr->a6 = *in6;
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iaddr->family = AF_INET6;
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}
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static inline struct in6_addr *inetpeer_get_addr_v6(struct inetpeer_addr *iaddr)
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{
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return &iaddr->a6;
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}
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/* can be called with or without local BH being disabled */
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struct inet_peer *inet_getpeer(struct inet_peer_base *base,
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const struct inetpeer_addr *daddr,
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int create);
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static inline struct inet_peer *inet_getpeer_v4(struct inet_peer_base *base,
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__be32 v4daddr,
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int vif, int create)
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{
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struct inetpeer_addr daddr;
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daddr.a4.addr = v4daddr;
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daddr.a4.vif = vif;
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daddr.family = AF_INET;
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return inet_getpeer(base, &daddr, create);
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}
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static inline struct inet_peer *inet_getpeer_v6(struct inet_peer_base *base,
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const struct in6_addr *v6daddr,
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int create)
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{
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struct inetpeer_addr daddr;
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daddr.a6 = *v6daddr;
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daddr.family = AF_INET6;
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return inet_getpeer(base, &daddr, create);
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}
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static inline int inetpeer_addr_cmp(const struct inetpeer_addr *a,
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const struct inetpeer_addr *b)
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{
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int i, n;
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if (a->family == AF_INET)
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n = sizeof(a->a4) / sizeof(u32);
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else
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n = sizeof(a->a6) / sizeof(u32);
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for (i = 0; i < n; i++) {
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if (a->key[i] == b->key[i])
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continue;
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if (a->key[i] < b->key[i])
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return -1;
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return 1;
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}
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return 0;
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}
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/* can be called from BH context or outside */
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void inet_putpeer(struct inet_peer *p);
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bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout);
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void inetpeer_invalidate_tree(struct inet_peer_base *);
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#endif /* _NET_INETPEER_H */
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