xref: /freebsd/sys/net/netisr.h (revision 273c26a3c3bea87a241d6879abd4f991db180bf0)
1 /*-
2  * Copyright (c) 2007-2009 Robert N. M. Watson
3  * Copyright (c) 2010-2011 Juniper Networks, Inc.
4  * All rights reserved.
5  *
6  * This software was developed by Robert N. M. Watson under contract
7  * to Juniper Networks, Inc.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  *
30  * $FreeBSD$
31  */
32 
33 #ifndef _NET_NETISR_H_
34 #define _NET_NETISR_H_
35 
36 /*
37  * The netisr (network interrupt service routine) provides a deferred
38  * execution evironment in which (generally inbound) network processing can
39  * take place.  Protocols register handlers which will be executed directly,
40  * or via deferred dispatch, depending on the circumstances.
41  *
42  * Historically, this was implemented by the BSD software ISR facility; it is
43  * now implemented via a software ithread (SWI).
44  */
45 
46 /*
47  * Protocol numbers, which are encoded in monitoring applications and kernel
48  * modules.  Internally, these are used in bit shift operations so must have
49  * a value 0 < proto < 32; we currently further limit at compile-time to 16
50  * for array-sizing purposes.
51  */
52 #define	NETISR_IP	1
53 #define	NETISR_IGMP	2		/* IGMPv3 output queue */
54 #define	NETISR_ROUTE	3		/* routing socket */
55 #define	NETISR_ARP	4		/* same as AF_LINK */
56 #define	NETISR_ETHER	5		/* ethernet input */
57 #define	NETISR_IPV6	6
58 #define	NETISR_NATM	7
59 #define	NETISR_EPAIR	8		/* if_epair(4) */
60 #define	NETISR_IP_DIRECT	9	/* direct-dispatch IPv4 */
61 #define	NETISR_IPV6_DIRECT	10	/* direct-dispatch IPv6 */
62 
63 /*
64  * Protocol ordering and affinity policy constants.  See the detailed
65  * discussion of policies later in the file.
66  */
67 #define	NETISR_POLICY_SOURCE	1	/* Maintain source ordering. */
68 #define	NETISR_POLICY_FLOW	2	/* Maintain flow ordering. */
69 #define	NETISR_POLICY_CPU	3	/* Protocol determines CPU placement. */
70 
71 /*
72  * Protocol dispatch policy constants; selects whether and when direct
73  * dispatch is permitted.
74  */
75 #define	NETISR_DISPATCH_DEFAULT		0	/* Use global default. */
76 #define	NETISR_DISPATCH_DEFERRED	1	/* Always defer dispatch. */
77 #define	NETISR_DISPATCH_HYBRID		2	/* Allow hybrid dispatch. */
78 #define	NETISR_DISPATCH_DIRECT		3	/* Always direct dispatch. */
79 
80 /*
81  * Monitoring data structures, exported by sysctl(2).
82  *
83  * Three sysctls are defined.  First, a per-protocol structure exported by
84  * net.isr.proto.
85  */
86 #define	NETISR_NAMEMAXLEN	32
87 struct sysctl_netisr_proto {
88 	u_int	snp_version;			/* Length of struct. */
89 	char	snp_name[NETISR_NAMEMAXLEN];	/* nh_name */
90 	u_int	snp_proto;			/* nh_proto */
91 	u_int	snp_qlimit;			/* nh_qlimit */
92 	u_int	snp_policy;			/* nh_policy */
93 	u_int	snp_flags;			/* Various flags. */
94 	u_int	snp_dispatch;			/* Dispatch policy. */
95 	u_int	_snp_ispare[6];
96 };
97 
98 /*
99  * Flags for sysctl_netisr_proto.snp_flags.
100  */
101 #define	NETISR_SNP_FLAGS_M2FLOW		0x00000001	/* nh_m2flow */
102 #define	NETISR_SNP_FLAGS_M2CPUID	0x00000002	/* nh_m2cpuid */
103 #define	NETISR_SNP_FLAGS_DRAINEDCPU	0x00000004	/* nh_drainedcpu */
104 
105 /*
106  * Next, a structure per-workstream, with per-protocol data, exported as
107  * net.isr.workstream.
108  */
109 struct sysctl_netisr_workstream {
110 	u_int	snws_version;			/* Length of struct. */
111 	u_int	snws_flags;			/* Various flags. */
112 	u_int	snws_wsid;			/* Workstream ID. */
113 	u_int	snws_cpu;			/* nws_cpu */
114 	u_int	_snws_ispare[12];
115 };
116 
117 /*
118  * Flags for sysctl_netisr_workstream.snws_flags
119  */
120 #define	NETISR_SNWS_FLAGS_INTR		0x00000001	/* nws_intr_event */
121 
122 /*
123  * Finally, a per-workstream-per-protocol structure, exported as
124  * net.isr.work.
125  */
126 struct sysctl_netisr_work {
127 	u_int	snw_version;			/* Length of struct. */
128 	u_int	snw_wsid;			/* Workstream ID. */
129 	u_int	snw_proto;			/* Protocol number. */
130 	u_int	snw_len;			/* nw_len */
131 	u_int	snw_watermark;			/* nw_watermark */
132 	u_int	_snw_ispare[3];
133 
134 	uint64_t	snw_dispatched;		/* nw_dispatched */
135 	uint64_t	snw_hybrid_dispatched;	/* nw_hybrid_dispatched */
136 	uint64_t	snw_qdrops;		/* nw_qdrops */
137 	uint64_t	snw_queued;		/* nw_queued */
138 	uint64_t	snw_handled;		/* nw_handled */
139 
140 	uint64_t	_snw_llspare[7];
141 };
142 
143 #ifdef _KERNEL
144 
145 /*-
146  * Protocols express ordering constraints and affinity preferences by
147  * implementing one or neither of nh_m2flow and nh_m2cpuid, which are used by
148  * netisr to determine which per-CPU workstream to assign mbufs to.
149  *
150  * The following policies may be used by protocols:
151  *
152  * NETISR_POLICY_SOURCE - netisr should maintain source ordering without
153  *                        advice from the protocol.  netisr will ignore any
154  *                        flow IDs present on the mbuf for the purposes of
155  *                        work placement.
156  *
157  * NETISR_POLICY_FLOW - netisr should maintain flow ordering as defined by
158  *                      the mbuf header flow ID field.  If the protocol
159  *                      implements nh_m2flow, then netisr will query the
160  *                      protocol in the event that the mbuf doesn't have a
161  *                      flow ID, falling back on source ordering.
162  *
163  * NETISR_POLICY_CPU - netisr will delegate all work placement decisions to
164  *                     the protocol, querying nh_m2cpuid for each packet.
165  *
166  * Protocols might make decisions about work placement based on an existing
167  * calculated flow ID on the mbuf, such as one provided in hardware, the
168  * receive interface pointed to by the mbuf (if any), the optional source
169  * identifier passed at some dispatch points, or even parse packet headers to
170  * calculate a flow.  Both protocol handlers may return a new mbuf pointer
171  * for the chain, or NULL if the packet proves invalid or m_pullup() fails.
172  *
173  * XXXRW: If we eventually support dynamic reconfiguration, there should be
174  * protocol handlers to notify them of CPU configuration changes so that they
175  * can rebalance work.
176  */
177 struct mbuf;
178 typedef void		 netisr_handler_t(struct mbuf *m);
179 typedef struct mbuf	*netisr_m2cpuid_t(struct mbuf *m, uintptr_t source,
180 			 u_int *cpuid);
181 typedef	struct mbuf	*netisr_m2flow_t(struct mbuf *m, uintptr_t source);
182 typedef void		 netisr_drainedcpu_t(u_int cpuid);
183 
184 #define	NETISR_CPUID_NONE	((u_int)-1)	/* No affinity returned. */
185 
186 /*
187  * Data structure describing a protocol handler.
188  */
189 struct netisr_handler {
190 	const char	*nh_name;	/* Character string protocol name. */
191 	netisr_handler_t *nh_handler;	/* Protocol handler. */
192 	netisr_m2flow_t	*nh_m2flow;	/* Query flow for untagged packet. */
193 	netisr_m2cpuid_t *nh_m2cpuid;	/* Query CPU to process mbuf on. */
194 	netisr_drainedcpu_t *nh_drainedcpu; /* Callback when drained a queue. */
195 	u_int		 nh_proto;	/* Integer protocol ID. */
196 	u_int		 nh_qlimit;	/* Maximum per-CPU queue depth. */
197 	u_int		 nh_policy;	/* Work placement policy. */
198 	u_int		 nh_dispatch;	/* Dispatch policy. */
199 	u_int		 nh_ispare[4];	/* For future use. */
200 	void		*nh_pspare[4];	/* For future use. */
201 };
202 
203 /*
204  * Register, unregister, and other netisr handler management functions.
205  */
206 void	netisr_clearqdrops(const struct netisr_handler *nhp);
207 void	netisr_getqdrops(const struct netisr_handler *nhp,
208 	    u_int64_t *qdropsp);
209 void	netisr_getqlimit(const struct netisr_handler *nhp, u_int *qlimitp);
210 void	netisr_register(const struct netisr_handler *nhp);
211 int	netisr_setqlimit(const struct netisr_handler *nhp, u_int qlimit);
212 void	netisr_unregister(const struct netisr_handler *nhp);
213 #ifdef VIMAGE
214 void	netisr_register_vnet(const struct netisr_handler *nhp);
215 void	netisr_unregister_vnet(const struct netisr_handler *nhp);
216 #endif
217 
218 /*
219  * Process a packet destined for a protocol, and attempt direct dispatch.
220  * Supplemental source ordering information can be passed using the _src
221  * variant.
222  */
223 int	netisr_dispatch(u_int proto, struct mbuf *m);
224 int	netisr_dispatch_src(u_int proto, uintptr_t source, struct mbuf *m);
225 int	netisr_queue(u_int proto, struct mbuf *m);
226 int	netisr_queue_src(u_int proto, uintptr_t source, struct mbuf *m);
227 
228 /*
229  * Provide a default implementation of "map an ID to a CPU ID".
230  */
231 u_int	netisr_default_flow2cpu(u_int flowid);
232 
233 /*
234  * Utility routines to return the number of CPUs participting in netisr, and
235  * to return a mapping from a number to a CPU ID that can be used with the
236  * scheduler.
237  */
238 u_int	netisr_get_cpucount(void);
239 u_int	netisr_get_cpuid(u_int cpunumber);
240 
241 /*
242  * Interfaces between DEVICE_POLLING and netisr.
243  */
244 void	netisr_sched_poll(void);
245 void	netisr_poll(void);
246 void	netisr_pollmore(void);
247 
248 #endif /* !_KERNEL */
249 #endif /* !_NET_NETISR_H_ */
250