bd085ef678
The MTU update code is supposed to be invoked in response to real
networking events that update the PMTU. In IPv6 PMTU update function
__ip6_rt_update_pmtu() we called dst_confirm_neigh() to update neighbor
confirmed time.
But for tunnel code, it will call pmtu before xmit, like:
- tnl_update_pmtu()
- skb_dst_update_pmtu()
- ip6_rt_update_pmtu()
- __ip6_rt_update_pmtu()
- dst_confirm_neigh()
If the tunnel remote dst mac address changed and we still do the neigh
confirm, we will not be able to update neigh cache and ping6 remote
will failed.
So for this ip_tunnel_xmit() case, _EVEN_ if the MTU is changed, we
should not be invoking dst_confirm_neigh() as we have no evidence
of successful two-way communication at this point.
On the other hand it is also important to keep the neigh reachability fresh
for TCP flows, so we cannot remove this dst_confirm_neigh() call.
To fix the issue, we have to add a new bool parameter for dst_ops.update_pmtu
to choose whether we should do neigh update or not. I will add the parameter
in this patch and set all the callers to true to comply with the previous
way, and fix the tunnel code one by one on later patches.
v5: No change.
v4: No change.
v3: Do not remove dst_confirm_neigh, but add a new bool parameter in
dst_ops.update_pmtu to control whether we should do neighbor confirm.
Also split the big patch to small ones for each area.
v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu.
Suggested-by: David Miller <davem@davemloft.net>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
155 lines
4.1 KiB
C
155 lines
4.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* INET An implementation of the TCP/IP protocol suite for the LINUX
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* operating system. INET is implemented using the BSD Socket
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* interface as the means of communication with the user level.
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*
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* Support for INET6 connection oriented protocols.
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*
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* Authors: See the TCPv6 sources
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*/
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#include <linux/module.h>
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#include <linux/in6.h>
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#include <linux/ipv6.h>
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#include <linux/jhash.h>
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#include <linux/slab.h>
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#include <net/addrconf.h>
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#include <net/inet_connection_sock.h>
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#include <net/inet_ecn.h>
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#include <net/inet_hashtables.h>
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#include <net/ip6_route.h>
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#include <net/sock.h>
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#include <net/inet6_connection_sock.h>
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#include <net/sock_reuseport.h>
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struct dst_entry *inet6_csk_route_req(const struct sock *sk,
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struct flowi6 *fl6,
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const struct request_sock *req,
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u8 proto)
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{
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struct inet_request_sock *ireq = inet_rsk(req);
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const struct ipv6_pinfo *np = inet6_sk(sk);
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struct in6_addr *final_p, final;
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struct dst_entry *dst;
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memset(fl6, 0, sizeof(*fl6));
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fl6->flowi6_proto = proto;
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fl6->daddr = ireq->ir_v6_rmt_addr;
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rcu_read_lock();
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final_p = fl6_update_dst(fl6, rcu_dereference(np->opt), &final);
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rcu_read_unlock();
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fl6->saddr = ireq->ir_v6_loc_addr;
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fl6->flowi6_oif = ireq->ir_iif;
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fl6->flowi6_mark = ireq->ir_mark;
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fl6->fl6_dport = ireq->ir_rmt_port;
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fl6->fl6_sport = htons(ireq->ir_num);
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fl6->flowi6_uid = sk->sk_uid;
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security_req_classify_flow(req, flowi6_to_flowi(fl6));
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dst = ip6_dst_lookup_flow(sock_net(sk), sk, fl6, final_p);
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if (IS_ERR(dst))
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return NULL;
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return dst;
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}
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EXPORT_SYMBOL(inet6_csk_route_req);
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void inet6_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
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{
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struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) uaddr;
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sin6->sin6_family = AF_INET6;
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sin6->sin6_addr = sk->sk_v6_daddr;
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sin6->sin6_port = inet_sk(sk)->inet_dport;
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/* We do not store received flowlabel for TCP */
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sin6->sin6_flowinfo = 0;
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sin6->sin6_scope_id = ipv6_iface_scope_id(&sin6->sin6_addr,
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sk->sk_bound_dev_if);
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}
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EXPORT_SYMBOL_GPL(inet6_csk_addr2sockaddr);
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static inline
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struct dst_entry *__inet6_csk_dst_check(struct sock *sk, u32 cookie)
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{
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return __sk_dst_check(sk, cookie);
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}
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static struct dst_entry *inet6_csk_route_socket(struct sock *sk,
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struct flowi6 *fl6)
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{
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struct inet_sock *inet = inet_sk(sk);
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struct ipv6_pinfo *np = inet6_sk(sk);
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struct in6_addr *final_p, final;
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struct dst_entry *dst;
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memset(fl6, 0, sizeof(*fl6));
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fl6->flowi6_proto = sk->sk_protocol;
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fl6->daddr = sk->sk_v6_daddr;
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fl6->saddr = np->saddr;
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fl6->flowlabel = np->flow_label;
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IP6_ECN_flow_xmit(sk, fl6->flowlabel);
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fl6->flowi6_oif = sk->sk_bound_dev_if;
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fl6->flowi6_mark = sk->sk_mark;
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fl6->fl6_sport = inet->inet_sport;
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fl6->fl6_dport = inet->inet_dport;
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fl6->flowi6_uid = sk->sk_uid;
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security_sk_classify_flow(sk, flowi6_to_flowi(fl6));
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rcu_read_lock();
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final_p = fl6_update_dst(fl6, rcu_dereference(np->opt), &final);
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rcu_read_unlock();
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dst = __inet6_csk_dst_check(sk, np->dst_cookie);
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if (!dst) {
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dst = ip6_dst_lookup_flow(sock_net(sk), sk, fl6, final_p);
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if (!IS_ERR(dst))
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ip6_dst_store(sk, dst, NULL, NULL);
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}
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return dst;
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}
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int inet6_csk_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl_unused)
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{
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struct ipv6_pinfo *np = inet6_sk(sk);
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struct flowi6 fl6;
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struct dst_entry *dst;
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int res;
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dst = inet6_csk_route_socket(sk, &fl6);
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if (IS_ERR(dst)) {
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sk->sk_err_soft = -PTR_ERR(dst);
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sk->sk_route_caps = 0;
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kfree_skb(skb);
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return PTR_ERR(dst);
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}
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rcu_read_lock();
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skb_dst_set_noref(skb, dst);
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/* Restore final destination back after routing done */
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fl6.daddr = sk->sk_v6_daddr;
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res = ip6_xmit(sk, skb, &fl6, sk->sk_mark, rcu_dereference(np->opt),
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np->tclass, sk->sk_priority);
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rcu_read_unlock();
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return res;
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}
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EXPORT_SYMBOL_GPL(inet6_csk_xmit);
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struct dst_entry *inet6_csk_update_pmtu(struct sock *sk, u32 mtu)
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{
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struct flowi6 fl6;
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struct dst_entry *dst = inet6_csk_route_socket(sk, &fl6);
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if (IS_ERR(dst))
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return NULL;
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dst->ops->update_pmtu(dst, sk, NULL, mtu, true);
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dst = inet6_csk_route_socket(sk, &fl6);
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return IS_ERR(dst) ? NULL : dst;
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}
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EXPORT_SYMBOL_GPL(inet6_csk_update_pmtu);
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