netisr.h revision 194201 
1/*-
2 * Copyright (c) 2007-2009 Robert N. M. Watson
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: head/sys/net/netisr.h 194201 2009-06-14 17:15:18Z bz $
27 */
28
29#ifndef _NET_NETISR_H_
30#define _NET_NETISR_H_
31#ifdef _KERNEL
32
33/*
34 * The netisr (network interrupt service routine) provides a deferred
35 * execution evironment in which (generally inbound) network processing can
36 * take place.  Protocols register handlers which will be executed directly,
37 * or via deferred dispatch, depending on the circumstances.
38 *
39 * Historically, this was implemented by the BSD software ISR facility; it is
40 * now implemented via a software ithread (SWI).
41 */
42#define	NETISR_IP	1
43#define	NETISR_IGMP	2		/* IGMPv3 output queue */
44#define	NETISR_ROUTE	3		/* routing socket */
45#define	NETISR_AARP	4		/* Appletalk ARP */
46#define	NETISR_ATALK2	5		/* Appletalk phase 2 */
47#define	NETISR_ATALK1	6		/* Appletalk phase 1 */
48#define	NETISR_ARP	7		/* same as AF_LINK */
49#define	NETISR_IPX	8		/* same as AF_IPX */
50#define	NETISR_ETHER	9		/* ethernet input */
51#define	NETISR_IPV6	10
52#define	NETISR_NATM	11
53
54/*-
55 * Protocols express ordering constraints and affinity preferences by
56 * implementing one or neither of nh_m2flow and nh_m2cpuid, which are used by
57 * netisr to determine which per-CPU workstream to assign mbufs to.
58 *
59 * The following policies may be used by protocols:
60 *
61 * NETISR_POLICY_SOURCE - netisr should maintain source ordering without
62 *                        advice from the protocol.  netisr will ignore any
63 *                        flow IDs present on the mbuf for the purposes of
64 *                        work placement.
65 *
66 * NETISR_POLICY_FLOW - netisr should maintain flow ordering as defined by
67 *                      the mbuf header flow ID field.  If the protocol
68 *                      implements nh_m2flow, then netisr will query the
69 *                      protocol in the event that the mbuf doesn't have a
70 *                      flow ID, falling back on source ordering.
71 *
72 * NETISR_POLICY_CPU - netisr will delegate all work placement decisions to
73 *                     the protocol, querying nh_m2cpuid for each packet.
74 *
75 * Protocols might make decisions about work placement based on an existing
76 * calculated flow ID on the mbuf, such as one provided in hardware, the
77 * receive interface pointed to by the mbuf (if any), the optional source
78 * identifier passed at some dispatch points, or even parse packet headers to
79 * calculate a flow.  Both protocol handlers may return a new mbuf pointer
80 * for the chain, or NULL if the packet proves invalid or m_pullup() fails.
81 *
82 * XXXRW: If we eventually support dynamic reconfiguration, there should be
83 * protocol handlers to notify them of CPU configuration changes so that they
84 * can rebalance work.
85 */
86struct mbuf;
87typedef void		 netisr_handler_t (struct mbuf *m);
88typedef struct mbuf	*netisr_m2cpuid_t(struct mbuf *m, uintptr_t source,
89			 u_int *cpuid);
90typedef	struct mbuf	*netisr_m2flow_t(struct mbuf *m, uintptr_t source);
91typedef void		 netisr_drainedcpu_t(u_int cpuid);
92
93#define	NETISR_POLICY_SOURCE	1	/* Maintain source ordering. */
94#define	NETISR_POLICY_FLOW	2	/* Maintain flow ordering. */
95#define	NETISR_POLICY_CPU	3	/* Protocol determines CPU placement. */
96
97/*
98 * Data structure describing a protocol handler.
99 */
100struct netisr_handler {
101	const char	*nh_name;	/* Character string protocol name. */
102	netisr_handler_t *nh_handler;	/* Protocol handler. */
103	netisr_m2flow_t	*nh_m2flow;	/* Query flow for untagged packet. */
104	netisr_m2cpuid_t *nh_m2cpuid;	/* Query CPU to process mbuf on. */
105	netisr_drainedcpu_t *nh_drainedcpu; /* Callback when drained a queue. */
106	u_int		 nh_proto;	/* Integer protocol ID. */
107	u_int		 nh_qlimit;	/* Maximum per-CPU queue depth. */
108	u_int		 nh_policy;	/* Work placement policy. */
109	u_int		 nh_ispare[5];	/* For future use. */
110	void		*nh_pspare[4];	/* For future use. */
111};
112
113/*
114 * Register, unregister, and other netisr handler management functions.
115 */
116void	netisr_clearqdrops(const struct netisr_handler *nhp);
117void	netisr_getqdrops(const struct netisr_handler *nhp,
118	    u_int64_t *qdropsp);
119void	netisr_getqlimit(const struct netisr_handler *nhp, u_int *qlimitp);
120void	netisr_register(const struct netisr_handler *nhp);
121int	netisr_setqlimit(const struct netisr_handler *nhp, u_int qlimit);
122void	netisr_unregister(const struct netisr_handler *nhp);
123
124/*
125 * Process a packet destined for a protocol, and attempt direct dispatch.
126 * Supplemental source ordering information can be passed using the _src
127 * variant.
128 */
129int	netisr_dispatch(u_int proto, struct mbuf *m);
130int	netisr_dispatch_src(u_int proto, uintptr_t source, struct mbuf *m);
131int	netisr_queue(u_int proto, struct mbuf *m);
132int	netisr_queue_src(u_int proto, uintptr_t source, struct mbuf *m);
133
134/*
135 * Provide a default implementation of "map an ID to a CPU ID".
136 */
137u_int	netisr_default_flow2cpu(u_int flowid);
138
139/*
140 * Utility routines to return the number of CPUs participting in netisr, and
141 * to return a mapping from a number to a CPU ID that can be used with the
142 * scheduler.
143 */
144u_int	netisr_get_cpucount(void);
145u_int	netisr_get_cpuid(u_int cpunumber);
146
147/*
148 * Interfaces between DEVICE_POLLING and netisr.
149 */
150void	netisr_sched_poll(void);
151void	netisr_poll(void);
152void	netisr_pollmore(void);
153
154#endif /* !_KERNEL */
155#endif /* !_NET_NETISR_H_ */
156