netisr.c revision 191816
138494Sobrien/*- 238494Sobrien * Copyright (c) 2001,2002,2003 Jonathan Lemon <jlemon@FreeBSD.org> 338494Sobrien * Copyright (c) 1997, Stefan Esser <se@freebsd.org> 438494Sobrien * All rights reserved. 5174294Sobrien * 638494Sobrien * Redistribution and use in source and binary forms, with or without 738494Sobrien * modification, are permitted provided that the following conditions 838494Sobrien * are met: 938494Sobrien * 1. Redistributions of source code must retain the above copyright 1038494Sobrien * notice, this list of conditions and the following disclaimer. 1138494Sobrien * 2. Redistributions in binary form must reproduce the above copyright 1238494Sobrien * notice, this list of conditions and the following disclaimer in the 1338494Sobrien * documentation and/or other materials provided with the distribution. 1438494Sobrien * 1582794Sobrien * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 1638494Sobrien * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 1738494Sobrien * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 1838494Sobrien * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 1938494Sobrien * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 2038494Sobrien * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 2138494Sobrien * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 2238494Sobrien * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2338494Sobrien * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 2438494Sobrien * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 2538494Sobrien * SUCH DAMAGE. 2638494Sobrien * 2738494Sobrien * $FreeBSD: head/sys/net/netisr.c 191816 2009-05-05 10:56:12Z zec $ 2838494Sobrien */ 2982794Sobrien 3038494Sobrien#include "opt_device_polling.h" 3138494Sobrien 3238494Sobrien#include <sys/param.h> 3338494Sobrien#include <sys/bus.h> 3438494Sobrien#include <sys/rtprio.h> 3538494Sobrien#include <sys/systm.h> 3638494Sobrien#include <sys/interrupt.h> 3738494Sobrien#include <sys/kernel.h> 3838494Sobrien#include <sys/kthread.h> 3938494Sobrien#include <sys/lock.h> 4038494Sobrien#include <sys/malloc.h> 4138494Sobrien#include <sys/proc.h> 4238494Sobrien#include <sys/random.h> 4338494Sobrien#include <sys/resourcevar.h> 4438494Sobrien#include <sys/sysctl.h> 4538494Sobrien#include <sys/unistd.h> 4638494Sobrien#include <sys/vimage.h> 4738494Sobrien#include <machine/atomic.h> 4838494Sobrien#include <machine/cpu.h> 4938494Sobrien#include <machine/stdarg.h> 5082794Sobrien 5182794Sobrien#include <sys/mbuf.h> 5282794Sobrien#include <sys/socket.h> 5338494Sobrien 54#include <net/if.h> 55#include <net/if_types.h> 56#include <net/if_var.h> 57#include <net/netisr.h> 58 59volatile unsigned int netisr; /* scheduling bits for network */ 60 61struct netisr { 62 netisr_t *ni_handler; 63 struct ifqueue *ni_queue; 64 int ni_flags; 65} netisrs[32]; 66 67static void *net_ih; 68 69void 70legacy_setsoftnet(void) 71{ 72 swi_sched(net_ih, 0); 73} 74 75void 76netisr_register(int num, netisr_t *handler, struct ifqueue *inq, int flags) 77{ 78 79 KASSERT(!(num < 0 || num >= (sizeof(netisrs)/sizeof(*netisrs))), 80 ("bad isr %d", num)); 81 KASSERT(flags == 0 || flags == NETISR_FORCEQUEUE, 82 ("netisr_register: bad flags 0x%x\n", flags)); 83 netisrs[num].ni_handler = handler; 84 netisrs[num].ni_queue = inq; 85 netisrs[num].ni_flags = flags; 86} 87 88void 89netisr_unregister(int num) 90{ 91 struct netisr *ni; 92 93 KASSERT(!(num < 0 || num >= (sizeof(netisrs)/sizeof(*netisrs))), 94 ("bad isr %d", num)); 95 ni = &netisrs[num]; 96 ni->ni_handler = NULL; 97 if (ni->ni_queue != NULL) 98 IF_DRAIN(ni->ni_queue); 99 ni->ni_queue = NULL; 100} 101 102struct isrstat { 103 int isrs_count; /* dispatch count */ 104 int isrs_directed; /* ...directly dispatched */ 105 int isrs_deferred; /* ...queued instead */ 106 int isrs_queued; /* intentionally queueued */ 107 int isrs_drop; /* dropped 'cuz no handler */ 108 int isrs_swi_count; /* swi_net handlers called */ 109}; 110static struct isrstat isrstat; 111 112SYSCTL_NODE(_net, OID_AUTO, isr, CTLFLAG_RW, 0, "netisr counters"); 113 114static int netisr_direct = 1; 115SYSCTL_INT(_net_isr, OID_AUTO, direct, CTLFLAG_RW, 116 &netisr_direct, 0, "enable direct dispatch"); 117TUNABLE_INT("net.isr.direct", &netisr_direct); 118 119SYSCTL_INT(_net_isr, OID_AUTO, count, CTLFLAG_RD, 120 &isrstat.isrs_count, 0, ""); 121SYSCTL_INT(_net_isr, OID_AUTO, directed, CTLFLAG_RD, 122 &isrstat.isrs_directed, 0, ""); 123SYSCTL_INT(_net_isr, OID_AUTO, deferred, CTLFLAG_RD, 124 &isrstat.isrs_deferred, 0, ""); 125SYSCTL_INT(_net_isr, OID_AUTO, queued, CTLFLAG_RD, 126 &isrstat.isrs_queued, 0, ""); 127SYSCTL_INT(_net_isr, OID_AUTO, drop, CTLFLAG_RD, 128 &isrstat.isrs_drop, 0, ""); 129SYSCTL_INT(_net_isr, OID_AUTO, swi_count, CTLFLAG_RD, 130 &isrstat.isrs_swi_count, 0, ""); 131 132/* 133 * Process all packets currently present in a netisr queue. Used to 134 * drain an existing set of packets waiting for processing when we 135 * begin direct dispatch, to avoid processing packets out of order. 136 */ 137static void 138netisr_processqueue(struct netisr *ni) 139{ 140 struct mbuf *m; 141 142 for (;;) { 143 IF_DEQUEUE(ni->ni_queue, m); 144 if (m == NULL) 145 break; 146 VNET_ASSERT(m->m_pkthdr.rcvif != NULL); 147 CURVNET_SET(m->m_pkthdr.rcvif->if_vnet); 148 ni->ni_handler(m); 149 CURVNET_RESTORE(); 150 } 151} 152 153/* 154 * Call the netisr directly instead of queueing the packet, if possible. 155 */ 156void 157netisr_dispatch(int num, struct mbuf *m) 158{ 159 struct netisr *ni; 160 161 isrstat.isrs_count++; /* XXX redundant */ 162 KASSERT(!(num < 0 || num >= (sizeof(netisrs)/sizeof(*netisrs))), 163 ("bad isr %d", num)); 164 ni = &netisrs[num]; 165 if (ni->ni_queue == NULL) { 166 isrstat.isrs_drop++; 167 m_freem(m); 168 return; 169 } 170 171 /* 172 * Unless NETISR_FORCEQUEUE is set on the netisr (generally 173 * indicating that the handler still requires Giant, which cannot be 174 * acquired in arbitrary order with respect to a caller), directly 175 * dispatch handling of this packet. Source ordering is maintained 176 * by virtue of callers consistently calling one of queued or direct 177 * dispatch, and the forcequeue flag being immutable after 178 * registration. 179 */ 180 if (netisr_direct && !(ni->ni_flags & NETISR_FORCEQUEUE)) { 181 isrstat.isrs_directed++; 182 ni->ni_handler(m); 183 } else { 184 isrstat.isrs_deferred++; 185 if (IF_HANDOFF(ni->ni_queue, m, NULL)) 186 schednetisr(num); 187 } 188} 189 190/* 191 * Same as above, but always queue. 192 * This is either used in places where we are not confident that 193 * direct dispatch is possible, or where queueing is required. 194 * It returns (0) on success and ERRNO on failure. On failure the 195 * mbuf has been free'd. 196 */ 197int 198netisr_queue(int num, struct mbuf *m) 199{ 200 struct netisr *ni; 201 202 KASSERT(!(num < 0 || num >= (sizeof(netisrs)/sizeof(*netisrs))), 203 ("bad isr %d", num)); 204 ni = &netisrs[num]; 205 if (ni->ni_queue == NULL) { 206 isrstat.isrs_drop++; 207 m_freem(m); 208 return (ENXIO); 209 } 210 isrstat.isrs_queued++; 211 if (!IF_HANDOFF(ni->ni_queue, m, NULL)) 212 return (ENOBUFS); /* IF_HANDOFF has free'd the mbuf */ 213 schednetisr(num); 214 return (0); 215} 216 217static void 218swi_net(void *dummy) 219{ 220 struct netisr *ni; 221 u_int bits; 222 int i; 223#ifdef DEVICE_POLLING 224 const int polling = 1; 225#else 226 const int polling = 0; 227#endif 228 229 do { 230 bits = atomic_readandclear_int(&netisr); 231 if (bits == 0) 232 break; 233 while ((i = ffs(bits)) != 0) { 234 isrstat.isrs_swi_count++; 235 i--; 236 bits &= ~(1 << i); 237 ni = &netisrs[i]; 238 if (ni->ni_handler == NULL) { 239 printf("swi_net: unregistered isr %d.\n", i); 240 continue; 241 } 242 if (ni->ni_queue == NULL) 243 ni->ni_handler(NULL); 244 else 245 netisr_processqueue(ni); 246 } 247 } while (polling); 248} 249 250static void 251start_netisr(void *dummy) 252{ 253 254 if (swi_add(NULL, "net", swi_net, NULL, SWI_NET, INTR_MPSAFE, &net_ih)) 255 panic("start_netisr"); 256} 257SYSINIT(start_netisr, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_netisr, NULL); 258