4465b46900
This patch allows a host to be configured to respond to any address in a specified range as if it were local, without actually needing to configure the address on an interface. This is done through routing table configuration. For instance, to configure a host to respond to any address in 10.1/16 received on eth0 as a local address we can do: ip rule add from all iif eth0 lookup 200 ip route add local 10.1/16 dev lo proto kernel scope host src 127.0.0.1 table 200 This host is now reachable by any 10.1/16 address (route lookup on input for packets received on eth0 can find the route). On output, the rule will not be matched so that this host can still send packets to 10.1/16 (not sent on loopback). Presumably, external routing can be configured to make sense out of this. To make this work, we needed to modify the logic in finding the interface which is assigned a given source address for output (dev_ip_find). We perform a normal fib_lookup instead of just a lookup on the local table, and in the lookup we ignore the input interface for matching. This patch is useful to implement IP-anycast for subnets of virtual addresses. Signed-off-by: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
120 lines
2.3 KiB
C
120 lines
2.3 KiB
C
/*
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*
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* Generic internet FLOW.
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*
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*/
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#ifndef _NET_FLOW_H
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#define _NET_FLOW_H
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#include <linux/in6.h>
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#include <asm/atomic.h>
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struct flowi {
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int oif;
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int iif;
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__u32 mark;
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union {
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struct {
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__be32 daddr;
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__be32 saddr;
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__u8 tos;
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__u8 scope;
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} ip4_u;
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struct {
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struct in6_addr daddr;
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struct in6_addr saddr;
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__be32 flowlabel;
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} ip6_u;
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struct {
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__le16 daddr;
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__le16 saddr;
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__u8 scope;
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} dn_u;
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} nl_u;
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#define fld_dst nl_u.dn_u.daddr
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#define fld_src nl_u.dn_u.saddr
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#define fld_scope nl_u.dn_u.scope
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#define fl6_dst nl_u.ip6_u.daddr
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#define fl6_src nl_u.ip6_u.saddr
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#define fl6_flowlabel nl_u.ip6_u.flowlabel
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#define fl4_dst nl_u.ip4_u.daddr
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#define fl4_src nl_u.ip4_u.saddr
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#define fl4_tos nl_u.ip4_u.tos
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#define fl4_scope nl_u.ip4_u.scope
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__u8 proto;
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__u8 flags;
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#define FLOWI_FLAG_ANYSRC 0x01
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#define FLOWI_FLAG_MATCH_ANY_IIF 0x02
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union {
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struct {
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__be16 sport;
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__be16 dport;
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} ports;
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struct {
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__u8 type;
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__u8 code;
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} icmpt;
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struct {
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__le16 sport;
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__le16 dport;
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} dnports;
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__be32 spi;
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struct {
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__u8 type;
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} mht;
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} uli_u;
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#define fl_ip_sport uli_u.ports.sport
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#define fl_ip_dport uli_u.ports.dport
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#define fl_icmp_type uli_u.icmpt.type
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#define fl_icmp_code uli_u.icmpt.code
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#define fl_ipsec_spi uli_u.spi
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#define fl_mh_type uli_u.mht.type
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__u32 secid; /* used by xfrm; see secid.txt */
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} __attribute__((__aligned__(BITS_PER_LONG/8)));
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#define FLOW_DIR_IN 0
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#define FLOW_DIR_OUT 1
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#define FLOW_DIR_FWD 2
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struct net;
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struct sock;
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struct flow_cache_ops;
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struct flow_cache_object {
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const struct flow_cache_ops *ops;
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};
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struct flow_cache_ops {
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struct flow_cache_object *(*get)(struct flow_cache_object *);
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int (*check)(struct flow_cache_object *);
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void (*delete)(struct flow_cache_object *);
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};
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typedef struct flow_cache_object *(*flow_resolve_t)(
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struct net *net, struct flowi *key, u16 family,
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u8 dir, struct flow_cache_object *oldobj, void *ctx);
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extern struct flow_cache_object *flow_cache_lookup(
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struct net *net, struct flowi *key, u16 family,
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u8 dir, flow_resolve_t resolver, void *ctx);
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extern void flow_cache_flush(void);
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extern atomic_t flow_cache_genid;
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static inline int flow_cache_uli_match(struct flowi *fl1, struct flowi *fl2)
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{
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return (fl1->proto == fl2->proto &&
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!memcmp(&fl1->uli_u, &fl2->uli_u, sizeof(fl1->uli_u)));
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}
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#endif
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