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3f2fb9a834
David Lamparter noted a use case where the source address selection fails
to pick an address from a VRF interface - unnumbered interfaces.
Relevant commands from his script:
ip addr add 9.9.9.9/32 dev lo
ip link set lo up
ip link add name vrf0 type vrf table 101
ip rule add oif vrf0 table 101
ip rule add iif vrf0 table 101
ip link set vrf0 up
ip addr add 10.0.0.3/32 dev vrf0
ip link add name dummy2 type dummy
ip link set dummy2 master vrf0 up
--> note dummy2 has no address - unnumbered device
ip route add 10.2.2.2/32 dev dummy2 table 101
ip neigh add 10.2.2.2 dev dummy2 lladdr 02:00:00:00:00:02
tcpdump -ni dummy2 &
And using ping instead of his socat example:
$ ping -I vrf0 -c1 10.2.2.2
ping: Warning: source address might be selected on device other than vrf0.
PING 10.2.2.2 (10.2.2.2) from 9.9.9.9 vrf0: 56(84) bytes of data.
>From tcpdump:
12:57:29.449128 IP 9.9.9.9 > 10.2.2.2: ICMP echo request, id 2491, seq 1, length 64
Note the source address is from lo and is not a VRF local address. With
this patch:
$ ping -I vrf0 -c1 10.2.2.2
PING 10.2.2.2 (10.2.2.2) from 10.0.0.3 vrf0: 56(84) bytes of data.
>From tcpdump:
12:59:25.096426 IP 10.0.0.3 > 10.2.2.2: ICMP echo request, id 2113, seq 1, length 64
Now the source address comes from vrf0.
The ipv4 function for selecting source address takes a const argument.
Removing the const requires touching a lot of places, so instead
l3mdev_master_ifindex_rcu is changed to take a const argument and then
do the typecast to non-const as required by netdev_master_upper_dev_get_rcu.
This is similar to what l3mdev_fib_table_rcu does.
IPv6 for unnumbered interfaces appears to be selecting the addresses
properly.
Cc: David Lamparter <david@opensourcerouting.org>
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
100 lines
2.4 KiB
C
100 lines
2.4 KiB
C
/*
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* net/l3mdev/l3mdev.c - L3 master device implementation
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* Copyright (c) 2015 Cumulus Networks
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* Copyright (c) 2015 David Ahern <dsa@cumulusnetworks.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#include <linux/netdevice.h>
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#include <net/l3mdev.h>
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/**
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* l3mdev_master_ifindex - get index of L3 master device
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* @dev: targeted interface
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*/
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int l3mdev_master_ifindex_rcu(const struct net_device *dev)
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{
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int ifindex = 0;
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if (!dev)
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return 0;
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if (netif_is_l3_master(dev)) {
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ifindex = dev->ifindex;
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} else if (netif_is_l3_slave(dev)) {
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struct net_device *master;
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struct net_device *_dev = (struct net_device *)dev;
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/* netdev_master_upper_dev_get_rcu calls
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* list_first_or_null_rcu to walk the upper dev list.
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* list_first_or_null_rcu does not handle a const arg. We aren't
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* making changes, just want the master device from that list so
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* typecast to remove the const
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*/
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master = netdev_master_upper_dev_get_rcu(_dev);
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if (master)
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ifindex = master->ifindex;
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}
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return ifindex;
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}
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EXPORT_SYMBOL_GPL(l3mdev_master_ifindex_rcu);
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/**
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* l3mdev_fib_table - get FIB table id associated with an L3
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* master interface
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* @dev: targeted interface
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*/
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u32 l3mdev_fib_table_rcu(const struct net_device *dev)
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{
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u32 tb_id = 0;
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if (!dev)
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return 0;
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if (netif_is_l3_master(dev)) {
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if (dev->l3mdev_ops->l3mdev_fib_table)
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tb_id = dev->l3mdev_ops->l3mdev_fib_table(dev);
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} else if (netif_is_l3_slave(dev)) {
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/* Users of netdev_master_upper_dev_get_rcu need non-const,
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* but current inet_*type functions take a const
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*/
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struct net_device *_dev = (struct net_device *) dev;
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const struct net_device *master;
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master = netdev_master_upper_dev_get_rcu(_dev);
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if (master &&
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master->l3mdev_ops->l3mdev_fib_table)
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tb_id = master->l3mdev_ops->l3mdev_fib_table(master);
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}
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return tb_id;
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}
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EXPORT_SYMBOL_GPL(l3mdev_fib_table_rcu);
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u32 l3mdev_fib_table_by_index(struct net *net, int ifindex)
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{
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struct net_device *dev;
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u32 tb_id = 0;
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if (!ifindex)
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return 0;
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rcu_read_lock();
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dev = dev_get_by_index_rcu(net, ifindex);
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if (dev)
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tb_id = l3mdev_fib_table_rcu(dev);
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rcu_read_unlock();
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return tb_id;
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}
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EXPORT_SYMBOL_GPL(l3mdev_fib_table_by_index);
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