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90b93f1b31
When performing L3 offload, routes and nexthops are usually programmed
into two different tables in the underlying device. Therefore, the fact
that a nexthop resides in hardware does not necessarily mean that all
the associated routes also reside in hardware and vice-versa.
While the kernel can signal to user space the presence of a nexthop in
hardware (via 'RTNH_F_OFFLOAD'), it does not have a corresponding flag
for routes. In addition, the fact that a route resides in hardware does
not necessarily mean that the traffic is offloaded. For example,
unreachable routes (i.e., 'RTN_UNREACHABLE') are programmed to trap
packets to the CPU so that the kernel will be able to generate the
appropriate ICMP error packet.
This patch adds an "offload" and "trap" indications to IPv4 routes, so
that users will have better visibility into the offload process.
'struct fib_alias' is extended with two new fields that indicate if the
route resides in hardware or not and if it is offloading traffic from
the kernel or trapping packets to it. Note that the new fields are added
in the 6 bytes hole and therefore the struct still fits in a single
cache line [1].
Capable drivers are expected to invoke fib_alias_hw_flags_set() with the
route's key in order to set the flags.
The indications are dumped to user space via a new flags (i.e.,
'RTM_F_OFFLOAD' and 'RTM_F_TRAP') in the 'rtm_flags' field in the
ancillary header.
v2:
* Make use of 'struct fib_rt_info' in fib_alias_hw_flags_set()
[1]
struct fib_alias {
struct hlist_node fa_list; /* 0 16 */
struct fib_info * fa_info; /* 16 8 */
u8 fa_tos; /* 24 1 */
u8 fa_type; /* 25 1 */
u8 fa_state; /* 26 1 */
u8 fa_slen; /* 27 1 */
u32 tb_id; /* 28 4 */
s16 fa_default; /* 32 2 */
u8 offload:1; /* 34: 0 1 */
u8 trap:1; /* 34: 1 1 */
u8 unused:6; /* 34: 2 1 */
/* XXX 5 bytes hole, try to pack */
struct callback_head rcu __attribute__((__aligned__(8))); /* 40 16 */
/* size: 56, cachelines: 1, members: 12 */
/* sum members: 50, holes: 1, sum holes: 5 */
/* sum bitfield members: 8 bits (1 bytes) */
/* forced alignments: 1, forced holes: 1, sum forced holes: 5 */
/* last cacheline: 56 bytes */
} __attribute__((__aligned__(8)));
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
62 lines
1.6 KiB
C
62 lines
1.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _FIB_LOOKUP_H
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#define _FIB_LOOKUP_H
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#include <linux/types.h>
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#include <linux/list.h>
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#include <net/ip_fib.h>
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#include <net/nexthop.h>
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struct fib_alias {
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struct hlist_node fa_list;
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struct fib_info *fa_info;
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u8 fa_tos;
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u8 fa_type;
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u8 fa_state;
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u8 fa_slen;
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u32 tb_id;
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s16 fa_default;
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u8 offload:1,
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trap:1,
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unused:6;
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struct rcu_head rcu;
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};
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#define FA_S_ACCESSED 0x01
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/* Dont write on fa_state unless needed, to keep it shared on all cpus */
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static inline void fib_alias_accessed(struct fib_alias *fa)
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{
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if (!(fa->fa_state & FA_S_ACCESSED))
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fa->fa_state |= FA_S_ACCESSED;
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}
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/* Exported by fib_semantics.c */
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void fib_release_info(struct fib_info *);
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struct fib_info *fib_create_info(struct fib_config *cfg,
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struct netlink_ext_ack *extack);
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int fib_nh_match(struct fib_config *cfg, struct fib_info *fi,
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struct netlink_ext_ack *extack);
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bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi);
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int fib_dump_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
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struct fib_rt_info *fri, unsigned int flags);
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void rtmsg_fib(int event, __be32 key, struct fib_alias *fa, int dst_len,
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u32 tb_id, const struct nl_info *info, unsigned int nlm_flags);
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static inline void fib_result_assign(struct fib_result *res,
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struct fib_info *fi)
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{
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/* we used to play games with refcounts, but we now use RCU */
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res->fi = fi;
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res->nhc = fib_info_nhc(fi, 0);
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}
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struct fib_prop {
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int error;
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u8 scope;
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};
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extern const struct fib_prop fib_props[RTN_MAX + 1];
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#endif /* _FIB_LOOKUP_H */
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