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![Andy Gospodarek](/assets/img/avatar_default.png)
This feature is only enabled with the new per-interface or ipv4 global sysctls called 'ignore_routes_with_linkdown'. net.ipv4.conf.all.ignore_routes_with_linkdown = 0 net.ipv4.conf.default.ignore_routes_with_linkdown = 0 net.ipv4.conf.lo.ignore_routes_with_linkdown = 0 ... When the above sysctls are set, will report to userspace that a route is dead and will no longer resolve to this nexthop when performing a fib lookup. This will signal to userspace that the route will not be selected. The signalling of a RTNH_F_DEAD is only passed to userspace if the sysctl is enabled and link is down. This was done as without it the netlink listeners would have no idea whether or not a nexthop would be selected. The kernel only sets RTNH_F_DEAD internally if the interface has IFF_UP cleared. With the new sysctl set, the following behavior can be observed (interface p8p1 is link-down): default via 10.0.5.2 dev p9p1 10.0.5.0/24 dev p9p1 proto kernel scope link src 10.0.5.15 70.0.0.0/24 dev p7p1 proto kernel scope link src 70.0.0.1 80.0.0.0/24 dev p8p1 proto kernel scope link src 80.0.0.1 dead linkdown 90.0.0.0/24 via 80.0.0.2 dev p8p1 metric 1 dead linkdown 90.0.0.0/24 via 70.0.0.2 dev p7p1 metric 2 90.0.0.1 via 70.0.0.2 dev p7p1 src 70.0.0.1 cache local 80.0.0.1 dev lo src 80.0.0.1 cache <local> 80.0.0.2 via 10.0.5.2 dev p9p1 src 10.0.5.15 cache While the route does remain in the table (so it can be modified if needed rather than being wiped away as it would be if IFF_UP was cleared), the proper next-hop is chosen automatically when the link is down. Now interface p8p1 is linked-up: default via 10.0.5.2 dev p9p1 10.0.5.0/24 dev p9p1 proto kernel scope link src 10.0.5.15 70.0.0.0/24 dev p7p1 proto kernel scope link src 70.0.0.1 80.0.0.0/24 dev p8p1 proto kernel scope link src 80.0.0.1 90.0.0.0/24 via 80.0.0.2 dev p8p1 metric 1 90.0.0.0/24 via 70.0.0.2 dev p7p1 metric 2 192.168.56.0/24 dev p2p1 proto kernel scope link src 192.168.56.2 90.0.0.1 via 80.0.0.2 dev p8p1 src 80.0.0.1 cache local 80.0.0.1 dev lo src 80.0.0.1 cache <local> 80.0.0.2 dev p8p1 src 80.0.0.1 cache and the output changes to what one would expect. If the sysctl is not set, the following output would be expected when p8p1 is down: default via 10.0.5.2 dev p9p1 10.0.5.0/24 dev p9p1 proto kernel scope link src 10.0.5.15 70.0.0.0/24 dev p7p1 proto kernel scope link src 70.0.0.1 80.0.0.0/24 dev p8p1 proto kernel scope link src 80.0.0.1 linkdown 90.0.0.0/24 via 80.0.0.2 dev p8p1 metric 1 linkdown 90.0.0.0/24 via 70.0.0.2 dev p7p1 metric 2 Since the dead flag does not appear, there should be no expectation that the kernel would skip using this route due to link being down. v2: Split kernel changes into 2 patches, this actually makes a behavioral change if the sysctl is set. Also took suggestion from Alex to simplify code by only checking sysctl during fib lookup and suggestion from Scott to add a per-interface sysctl. v3: Code clean-ups to make it more readable and efficient as well as a reverse path check fix. v4: Drop binary sysctl v5: Whitespace fixups from Dave v6: Style changes from Dave and checkpatch suggestions v7: One more checkpatch fixup Signed-off-by: Andy Gospodarek <gospo@cumulusnetworks.com> Signed-off-by: Dinesh Dutt <ddutt@cumulusnetworks.com> Acked-by: Scott Feldman <sfeldma@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
261 lines
7.7 KiB
C
261 lines
7.7 KiB
C
#ifndef _LINUX_INETDEVICE_H
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#define _LINUX_INETDEVICE_H
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#ifdef __KERNEL__
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#include <linux/bitmap.h>
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#include <linux/if.h>
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#include <linux/ip.h>
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#include <linux/netdevice.h>
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#include <linux/rcupdate.h>
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#include <linux/timer.h>
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#include <linux/sysctl.h>
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#include <linux/rtnetlink.h>
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struct ipv4_devconf {
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void *sysctl;
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int data[IPV4_DEVCONF_MAX];
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DECLARE_BITMAP(state, IPV4_DEVCONF_MAX);
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};
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#define MC_HASH_SZ_LOG 9
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struct in_device {
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struct net_device *dev;
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atomic_t refcnt;
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int dead;
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struct in_ifaddr *ifa_list; /* IP ifaddr chain */
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struct ip_mc_list __rcu *mc_list; /* IP multicast filter chain */
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struct ip_mc_list __rcu * __rcu *mc_hash;
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int mc_count; /* Number of installed mcasts */
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spinlock_t mc_tomb_lock;
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struct ip_mc_list *mc_tomb;
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unsigned long mr_v1_seen;
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unsigned long mr_v2_seen;
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unsigned long mr_maxdelay;
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unsigned char mr_qrv;
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unsigned char mr_gq_running;
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unsigned char mr_ifc_count;
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struct timer_list mr_gq_timer; /* general query timer */
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struct timer_list mr_ifc_timer; /* interface change timer */
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struct neigh_parms *arp_parms;
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struct ipv4_devconf cnf;
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struct rcu_head rcu_head;
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};
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#define IPV4_DEVCONF(cnf, attr) ((cnf).data[IPV4_DEVCONF_ ## attr - 1])
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#define IPV4_DEVCONF_ALL(net, attr) \
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IPV4_DEVCONF((*(net)->ipv4.devconf_all), attr)
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static inline int ipv4_devconf_get(struct in_device *in_dev, int index)
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{
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index--;
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return in_dev->cnf.data[index];
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}
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static inline void ipv4_devconf_set(struct in_device *in_dev, int index,
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int val)
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{
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index--;
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set_bit(index, in_dev->cnf.state);
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in_dev->cnf.data[index] = val;
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}
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static inline void ipv4_devconf_setall(struct in_device *in_dev)
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{
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bitmap_fill(in_dev->cnf.state, IPV4_DEVCONF_MAX);
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}
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#define IN_DEV_CONF_GET(in_dev, attr) \
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ipv4_devconf_get((in_dev), IPV4_DEVCONF_ ## attr)
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#define IN_DEV_CONF_SET(in_dev, attr, val) \
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ipv4_devconf_set((in_dev), IPV4_DEVCONF_ ## attr, (val))
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#define IN_DEV_ANDCONF(in_dev, attr) \
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(IPV4_DEVCONF_ALL(dev_net(in_dev->dev), attr) && \
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IN_DEV_CONF_GET((in_dev), attr))
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#define IN_DEV_NET_ORCONF(in_dev, net, attr) \
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(IPV4_DEVCONF_ALL(net, attr) || \
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IN_DEV_CONF_GET((in_dev), attr))
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#define IN_DEV_ORCONF(in_dev, attr) \
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IN_DEV_NET_ORCONF(in_dev, dev_net(in_dev->dev), attr)
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#define IN_DEV_MAXCONF(in_dev, attr) \
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(max(IPV4_DEVCONF_ALL(dev_net(in_dev->dev), attr), \
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IN_DEV_CONF_GET((in_dev), attr)))
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#define IN_DEV_FORWARD(in_dev) IN_DEV_CONF_GET((in_dev), FORWARDING)
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#define IN_DEV_MFORWARD(in_dev) IN_DEV_ANDCONF((in_dev), MC_FORWARDING)
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#define IN_DEV_RPFILTER(in_dev) IN_DEV_MAXCONF((in_dev), RP_FILTER)
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#define IN_DEV_SRC_VMARK(in_dev) IN_DEV_ORCONF((in_dev), SRC_VMARK)
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#define IN_DEV_SOURCE_ROUTE(in_dev) IN_DEV_ANDCONF((in_dev), \
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ACCEPT_SOURCE_ROUTE)
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#define IN_DEV_ACCEPT_LOCAL(in_dev) IN_DEV_ORCONF((in_dev), ACCEPT_LOCAL)
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#define IN_DEV_BOOTP_RELAY(in_dev) IN_DEV_ANDCONF((in_dev), BOOTP_RELAY)
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#define IN_DEV_LOG_MARTIANS(in_dev) IN_DEV_ORCONF((in_dev), LOG_MARTIANS)
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#define IN_DEV_PROXY_ARP(in_dev) IN_DEV_ORCONF((in_dev), PROXY_ARP)
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#define IN_DEV_PROXY_ARP_PVLAN(in_dev) IN_DEV_CONF_GET(in_dev, PROXY_ARP_PVLAN)
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#define IN_DEV_SHARED_MEDIA(in_dev) IN_DEV_ORCONF((in_dev), SHARED_MEDIA)
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#define IN_DEV_TX_REDIRECTS(in_dev) IN_DEV_ORCONF((in_dev), SEND_REDIRECTS)
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#define IN_DEV_SEC_REDIRECTS(in_dev) IN_DEV_ORCONF((in_dev), \
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SECURE_REDIRECTS)
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#define IN_DEV_IDTAG(in_dev) IN_DEV_CONF_GET(in_dev, TAG)
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#define IN_DEV_MEDIUM_ID(in_dev) IN_DEV_CONF_GET(in_dev, MEDIUM_ID)
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#define IN_DEV_PROMOTE_SECONDARIES(in_dev) \
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IN_DEV_ORCONF((in_dev), \
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PROMOTE_SECONDARIES)
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#define IN_DEV_ROUTE_LOCALNET(in_dev) IN_DEV_ORCONF(in_dev, ROUTE_LOCALNET)
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#define IN_DEV_NET_ROUTE_LOCALNET(in_dev, net) \
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IN_DEV_NET_ORCONF(in_dev, net, ROUTE_LOCALNET)
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#define IN_DEV_RX_REDIRECTS(in_dev) \
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((IN_DEV_FORWARD(in_dev) && \
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IN_DEV_ANDCONF((in_dev), ACCEPT_REDIRECTS)) \
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|| (!IN_DEV_FORWARD(in_dev) && \
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IN_DEV_ORCONF((in_dev), ACCEPT_REDIRECTS)))
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#define IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) \
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IN_DEV_CONF_GET((in_dev), IGNORE_ROUTES_WITH_LINKDOWN)
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#define IN_DEV_ARPFILTER(in_dev) IN_DEV_ORCONF((in_dev), ARPFILTER)
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#define IN_DEV_ARP_ACCEPT(in_dev) IN_DEV_ORCONF((in_dev), ARP_ACCEPT)
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#define IN_DEV_ARP_ANNOUNCE(in_dev) IN_DEV_MAXCONF((in_dev), ARP_ANNOUNCE)
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#define IN_DEV_ARP_IGNORE(in_dev) IN_DEV_MAXCONF((in_dev), ARP_IGNORE)
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#define IN_DEV_ARP_NOTIFY(in_dev) IN_DEV_MAXCONF((in_dev), ARP_NOTIFY)
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struct in_ifaddr {
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struct hlist_node hash;
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struct in_ifaddr *ifa_next;
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struct in_device *ifa_dev;
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struct rcu_head rcu_head;
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__be32 ifa_local;
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__be32 ifa_address;
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__be32 ifa_mask;
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__be32 ifa_broadcast;
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unsigned char ifa_scope;
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unsigned char ifa_prefixlen;
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__u32 ifa_flags;
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char ifa_label[IFNAMSIZ];
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/* In seconds, relative to tstamp. Expiry is at tstamp + HZ * lft. */
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__u32 ifa_valid_lft;
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__u32 ifa_preferred_lft;
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unsigned long ifa_cstamp; /* created timestamp */
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unsigned long ifa_tstamp; /* updated timestamp */
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};
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int register_inetaddr_notifier(struct notifier_block *nb);
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int unregister_inetaddr_notifier(struct notifier_block *nb);
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void inet_netconf_notify_devconf(struct net *net, int type, int ifindex,
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struct ipv4_devconf *devconf);
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struct net_device *__ip_dev_find(struct net *net, __be32 addr, bool devref);
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static inline struct net_device *ip_dev_find(struct net *net, __be32 addr)
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{
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return __ip_dev_find(net, addr, true);
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}
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int inet_addr_onlink(struct in_device *in_dev, __be32 a, __be32 b);
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int devinet_ioctl(struct net *net, unsigned int cmd, void __user *);
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void devinet_init(void);
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struct in_device *inetdev_by_index(struct net *, int);
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__be32 inet_select_addr(const struct net_device *dev, __be32 dst, int scope);
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__be32 inet_confirm_addr(struct net *net, struct in_device *in_dev, __be32 dst,
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__be32 local, int scope);
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struct in_ifaddr *inet_ifa_byprefix(struct in_device *in_dev, __be32 prefix,
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__be32 mask);
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static __inline__ int inet_ifa_match(__be32 addr, struct in_ifaddr *ifa)
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{
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return !((addr^ifa->ifa_address)&ifa->ifa_mask);
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}
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/*
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* Check if a mask is acceptable.
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*/
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static __inline__ int bad_mask(__be32 mask, __be32 addr)
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{
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__u32 hmask;
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if (addr & (mask = ~mask))
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return 1;
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hmask = ntohl(mask);
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if (hmask & (hmask+1))
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return 1;
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return 0;
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}
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#define for_primary_ifa(in_dev) { struct in_ifaddr *ifa; \
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for (ifa = (in_dev)->ifa_list; ifa && !(ifa->ifa_flags&IFA_F_SECONDARY); ifa = ifa->ifa_next)
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#define for_ifa(in_dev) { struct in_ifaddr *ifa; \
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for (ifa = (in_dev)->ifa_list; ifa; ifa = ifa->ifa_next)
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#define endfor_ifa(in_dev) }
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static inline struct in_device *__in_dev_get_rcu(const struct net_device *dev)
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{
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return rcu_dereference(dev->ip_ptr);
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}
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static inline struct in_device *in_dev_get(const struct net_device *dev)
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{
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struct in_device *in_dev;
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rcu_read_lock();
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in_dev = __in_dev_get_rcu(dev);
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if (in_dev)
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atomic_inc(&in_dev->refcnt);
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rcu_read_unlock();
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return in_dev;
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}
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static inline struct in_device *__in_dev_get_rtnl(const struct net_device *dev)
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{
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return rtnl_dereference(dev->ip_ptr);
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}
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static inline struct neigh_parms *__in_dev_arp_parms_get_rcu(const struct net_device *dev)
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{
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struct in_device *in_dev = __in_dev_get_rcu(dev);
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return in_dev ? in_dev->arp_parms : NULL;
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}
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void in_dev_finish_destroy(struct in_device *idev);
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static inline void in_dev_put(struct in_device *idev)
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{
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if (atomic_dec_and_test(&idev->refcnt))
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in_dev_finish_destroy(idev);
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}
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#define __in_dev_put(idev) atomic_dec(&(idev)->refcnt)
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#define in_dev_hold(idev) atomic_inc(&(idev)->refcnt)
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#endif /* __KERNEL__ */
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static __inline__ __be32 inet_make_mask(int logmask)
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{
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if (logmask)
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return htonl(~((1U<<(32-logmask))-1));
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return 0;
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}
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static __inline__ int inet_mask_len(__be32 mask)
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{
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__u32 hmask = ntohl(mask);
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if (!hmask)
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return 0;
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return 32 - ffz(~hmask);
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}
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#endif /* _LINUX_INETDEVICE_H */
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