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