1 /*- 2 * Copyright (c) 2001,2002,2003 Jonathan Lemon <jlemon@FreeBSD.org> 3 * Copyright (c) 1997, Stefan Esser <se@freebsd.org> 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 * 27 * $FreeBSD$ 28 */ 29 30 #include "opt_device_polling.h" 31 32 #include <sys/param.h> 33 #include <sys/bus.h> 34 #include <sys/rtprio.h> 35 #include <sys/systm.h> 36 #include <sys/interrupt.h> 37 #include <sys/kernel.h> 38 #include <sys/kthread.h> 39 #include <sys/lock.h> 40 #include <sys/malloc.h> 41 #include <sys/proc.h> 42 #include <sys/random.h> 43 #include <sys/resourcevar.h> 44 #include <sys/sysctl.h> 45 #include <sys/unistd.h> 46 #include <machine/atomic.h> 47 #include <machine/cpu.h> 48 #include <machine/stdarg.h> 49 50 #include <sys/mbuf.h> 51 #include <sys/socket.h> 52 53 #include <net/if.h> 54 #include <net/if_types.h> 55 #include <net/if_var.h> 56 #include <net/netisr.h> 57 58 volatile unsigned int netisr; /* scheduling bits for network */ 59 60 struct netisr { 61 netisr_t *ni_handler; 62 struct ifqueue *ni_queue; 63 int ni_flags; 64 } netisrs[32]; 65 66 static void *net_ih; 67 68 void 69 legacy_setsoftnet(void) 70 { 71 swi_sched(net_ih, 0); 72 } 73 74 void 75 netisr_register(int num, netisr_t *handler, struct ifqueue *inq, int flags) 76 { 77 78 KASSERT(!(num < 0 || num >= (sizeof(netisrs)/sizeof(*netisrs))), 79 ("bad isr %d", num)); 80 KASSERT(flags == 0 || flags == NETISR_FORCEQUEUE, 81 ("netisr_register: bad flags 0x%x\n", flags)); 82 netisrs[num].ni_handler = handler; 83 netisrs[num].ni_queue = inq; 84 netisrs[num].ni_flags = flags; 85 } 86 87 void 88 netisr_unregister(int num) 89 { 90 struct netisr *ni; 91 92 KASSERT(!(num < 0 || num >= (sizeof(netisrs)/sizeof(*netisrs))), 93 ("bad isr %d", num)); 94 ni = &netisrs[num]; 95 ni->ni_handler = NULL; 96 if (ni->ni_queue != NULL) 97 IF_DRAIN(ni->ni_queue); 98 ni->ni_queue = NULL; 99 } 100 101 struct isrstat { 102 int isrs_count; /* dispatch count */ 103 int isrs_directed; /* ...directly dispatched */ 104 int isrs_deferred; /* ...queued instead */ 105 int isrs_queued; /* intentionally queueued */ 106 int isrs_drop; /* dropped 'cuz no handler */ 107 int isrs_swi_count; /* swi_net handlers called */ 108 }; 109 static struct isrstat isrstat; 110 111 SYSCTL_NODE(_net, OID_AUTO, isr, CTLFLAG_RW, 0, "netisr counters"); 112 113 static int netisr_direct = 1; 114 SYSCTL_INT(_net_isr, OID_AUTO, direct, CTLFLAG_RW, 115 &netisr_direct, 0, "enable direct dispatch"); 116 TUNABLE_INT("net.isr.direct", &netisr_direct); 117 118 SYSCTL_INT(_net_isr, OID_AUTO, count, CTLFLAG_RD, 119 &isrstat.isrs_count, 0, ""); 120 SYSCTL_INT(_net_isr, OID_AUTO, directed, CTLFLAG_RD, 121 &isrstat.isrs_directed, 0, ""); 122 SYSCTL_INT(_net_isr, OID_AUTO, deferred, CTLFLAG_RD, 123 &isrstat.isrs_deferred, 0, ""); 124 SYSCTL_INT(_net_isr, OID_AUTO, queued, CTLFLAG_RD, 125 &isrstat.isrs_queued, 0, ""); 126 SYSCTL_INT(_net_isr, OID_AUTO, drop, CTLFLAG_RD, 127 &isrstat.isrs_drop, 0, ""); 128 SYSCTL_INT(_net_isr, OID_AUTO, swi_count, CTLFLAG_RD, 129 &isrstat.isrs_swi_count, 0, ""); 130 131 /* 132 * Process all packets currently present in a netisr queue. Used to 133 * drain an existing set of packets waiting for processing when we 134 * begin direct dispatch, to avoid processing packets out of order. 135 */ 136 static void 137 netisr_processqueue(struct netisr *ni) 138 { 139 struct mbuf *m; 140 141 for (;;) { 142 IF_DEQUEUE(ni->ni_queue, m); 143 if (m == NULL) 144 break; 145 ni->ni_handler(m); 146 } 147 } 148 149 /* 150 * Call the netisr directly instead of queueing the packet, if possible. 151 */ 152 void 153 netisr_dispatch(int num, struct mbuf *m) 154 { 155 struct netisr *ni; 156 157 isrstat.isrs_count++; /* XXX redundant */ 158 KASSERT(!(num < 0 || num >= (sizeof(netisrs)/sizeof(*netisrs))), 159 ("bad isr %d", num)); 160 ni = &netisrs[num]; 161 if (ni->ni_queue == NULL) { 162 isrstat.isrs_drop++; 163 m_freem(m); 164 return; 165 } 166 167 /* 168 * Unless NETISR_FORCEQUEUE is set on the netisr (generally 169 * indicating that the handler still requires Giant, which cannot be 170 * acquired in arbitrary order with respect to a caller), directly 171 * dispatch handling of this packet. Source ordering is maintained 172 * by virtue of callers consistently calling one of queued or direct 173 * dispatch, and the forcequeue flag being immutable after 174 * registration. 175 */ 176 if (netisr_direct && !(ni->ni_flags & NETISR_FORCEQUEUE)) { 177 isrstat.isrs_directed++; 178 ni->ni_handler(m); 179 } else { 180 isrstat.isrs_deferred++; 181 if (IF_HANDOFF(ni->ni_queue, m, NULL)) 182 schednetisr(num); 183 } 184 } 185 186 /* 187 * Same as above, but always queue. 188 * This is either used in places where we are not confident that 189 * direct dispatch is possible, or where queueing is required. 190 * It returns (0) on success and ERRNO on failure. On failure the 191 * mbuf has been free'd. 192 */ 193 int 194 netisr_queue(int num, struct mbuf *m) 195 { 196 struct netisr *ni; 197 198 KASSERT(!(num < 0 || num >= (sizeof(netisrs)/sizeof(*netisrs))), 199 ("bad isr %d", num)); 200 ni = &netisrs[num]; 201 if (ni->ni_queue == NULL) { 202 isrstat.isrs_drop++; 203 m_freem(m); 204 return (ENXIO); 205 } 206 isrstat.isrs_queued++; 207 if (!IF_HANDOFF(ni->ni_queue, m, NULL)) 208 return (ENOBUFS); /* IF_HANDOFF has free'd the mbuf */ 209 schednetisr(num); 210 return (0); 211 } 212 213 static void 214 swi_net(void *dummy) 215 { 216 struct netisr *ni; 217 u_int bits; 218 int i; 219 #ifdef DEVICE_POLLING 220 const int polling = 1; 221 #else 222 const int polling = 0; 223 #endif 224 225 do { 226 bits = atomic_readandclear_int(&netisr); 227 if (bits == 0) 228 break; 229 while ((i = ffs(bits)) != 0) { 230 isrstat.isrs_swi_count++; 231 i--; 232 bits &= ~(1 << i); 233 ni = &netisrs[i]; 234 if (ni->ni_handler == NULL) { 235 printf("swi_net: unregistered isr %d.\n", i); 236 continue; 237 } 238 if (ni->ni_queue == NULL) 239 ni->ni_handler(NULL); 240 else 241 netisr_processqueue(ni); 242 } 243 } while (polling); 244 } 245 246 static void 247 start_netisr(void *dummy) 248 { 249 250 if (swi_add(NULL, "net", swi_net, NULL, SWI_NET, INTR_MPSAFE, &net_ih)) 251 panic("start_netisr"); 252 } 253 SYSINIT(start_netisr, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_netisr, NULL); 254