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 <sys/param.h> 31 #include <sys/bus.h> 32 #include <sys/rtprio.h> 33 #include <sys/systm.h> 34 #include <sys/interrupt.h> 35 #include <sys/kernel.h> 36 #include <sys/kthread.h> 37 #include <sys/lock.h> 38 #include <sys/malloc.h> 39 #include <sys/proc.h> 40 #include <sys/random.h> 41 #include <sys/resourcevar.h> 42 #include <sys/sysctl.h> 43 #include <sys/unistd.h> 44 #include <machine/atomic.h> 45 #include <machine/cpu.h> 46 #include <machine/stdarg.h> 47 48 #include <sys/mbuf.h> 49 #include <sys/socket.h> 50 51 #include <net/if.h> 52 #include <net/if_types.h> 53 #include <net/if_var.h> 54 #include <net/netisr.h> 55 56 volatile unsigned int netisr; /* scheduling bits for network */ 57 58 struct netisr { 59 netisr_t *ni_handler; 60 struct ifqueue *ni_queue; 61 } netisrs[32]; 62 63 static struct mtx netisr_mtx; 64 static void *net_ih; 65 66 void 67 legacy_setsoftnet(void) 68 { 69 swi_sched(net_ih, 0); 70 } 71 72 void 73 netisr_register(int num, netisr_t *handler, struct ifqueue *inq) 74 { 75 76 KASSERT(!(num < 0 || num >= (sizeof(netisrs)/sizeof(*netisrs))), 77 ("bad isr %d", num)); 78 netisrs[num].ni_handler = handler; 79 netisrs[num].ni_queue = inq; 80 } 81 82 void 83 netisr_unregister(int num) 84 { 85 struct netisr *ni; 86 int s; 87 88 KASSERT(!(num < 0 || num >= (sizeof(netisrs)/sizeof(*netisrs))), 89 ("bad isr %d", num)); 90 ni = &netisrs[num]; 91 ni->ni_handler = NULL; 92 if (ni->ni_queue != NULL) { 93 s = splimp(); 94 IF_DRAIN(ni->ni_queue); 95 splx(s); 96 } 97 } 98 99 struct isrstat { 100 int isrs_count; /* dispatch count */ 101 int isrs_directed; /* ...successfully dispatched */ 102 int isrs_deferred; /* ...queued instead */ 103 int isrs_bypassed; /* bypassed queued packets */ 104 int isrs_queued; /* intentionally queueued */ 105 int isrs_swi_count; /* swi_net handlers called */ 106 }; 107 static struct isrstat isrstat; 108 109 SYSCTL_NODE(_net, OID_AUTO, isr, CTLFLAG_RW, 0, "netisr counters"); 110 111 static int netisr_enable = 0; 112 SYSCTL_INT(_net_isr, OID_AUTO, enable, CTLFLAG_RW, 113 &netisr_enable, 0, "enable direct dispatch"); 114 115 SYSCTL_INT(_net_isr, OID_AUTO, count, CTLFLAG_RD, 116 &isrstat.isrs_count, 0, ""); 117 SYSCTL_INT(_net_isr, OID_AUTO, directed, CTLFLAG_RD, 118 &isrstat.isrs_directed, 0, ""); 119 SYSCTL_INT(_net_isr, OID_AUTO, deferred, CTLFLAG_RD, 120 &isrstat.isrs_deferred, 0, ""); 121 SYSCTL_INT(_net_isr, OID_AUTO, bypassed, CTLFLAG_RD, 122 &isrstat.isrs_bypassed, 0, ""); 123 SYSCTL_INT(_net_isr, OID_AUTO, queued, CTLFLAG_RD, 124 &isrstat.isrs_queued, 0, ""); 125 SYSCTL_INT(_net_isr, OID_AUTO, swi_count, CTLFLAG_RD, 126 &isrstat.isrs_swi_count, 0, ""); 127 128 /* 129 * Call the netisr directly instead of queueing the packet, if possible. 130 * 131 * Ideally, the permissibility of calling the routine would be determined 132 * by checking if splnet() was asserted at the time the device interrupt 133 * occurred; if so, this indicates that someone is in the network stack. 134 * 135 * However, bus_setup_intr uses INTR_TYPE_NET, which sets splnet before 136 * calling the interrupt handler, so the previous mask is unavailable. 137 * Approximate this by checking intr_nesting_level instead; if any SWI 138 * handlers are running, the packet is queued instead. 139 */ 140 void 141 netisr_dispatch(int num, struct mbuf *m) 142 { 143 struct netisr *ni; 144 145 isrstat.isrs_count++; 146 KASSERT(!(num < 0 || num >= (sizeof(netisrs)/sizeof(*netisrs))), 147 ("bad isr %d", num)); 148 ni = &netisrs[num]; 149 KASSERT(ni->ni_queue != NULL, ("no queue for isr %d", num)); 150 if (netisr_enable && mtx_trylock(&netisr_mtx)) { 151 isrstat.isrs_directed++; 152 /* 153 * One slight problem here is that packets might bypass 154 * each other in the stack, if an earlier one happened 155 * to get stuck in the queue. 156 * 157 * we can either: 158 * a. drain the queue before handling this packet, 159 * b. fallback to queueing the packet, 160 * c. sweep the issue under the rug and ignore it. 161 * 162 * Currently, we do c), and keep a rough event counter. 163 */ 164 if (_IF_QLEN(ni->ni_queue) > 0) 165 isrstat.isrs_bypassed++; 166 ni->ni_handler(m); 167 mtx_unlock(&netisr_mtx); 168 } else { 169 isrstat.isrs_deferred++; 170 if (IF_HANDOFF(ni->ni_queue, m, NULL)) 171 schednetisr(num); 172 } 173 } 174 175 /* 176 * Same as above, but always queue. 177 * This is either used in places where we are not confident that 178 * direct dispatch is possible, or where queueing is required. 179 */ 180 int 181 netisr_queue(int num, struct mbuf *m) 182 { 183 struct netisr *ni; 184 185 KASSERT(!(num < 0 || num >= (sizeof(netisrs)/sizeof(*netisrs))), 186 ("bad isr %d", num)); 187 ni = &netisrs[num]; 188 KASSERT(ni->ni_queue != NULL, ("no queue for isr %d", num)); 189 isrstat.isrs_queued++; 190 if (!IF_HANDOFF(ni->ni_queue, m, NULL)) 191 return (0); 192 schednetisr(num); 193 return (1); 194 } 195 196 static void 197 swi_net(void *dummy) 198 { 199 struct netisr *ni; 200 struct mbuf *m; 201 u_int bits; 202 int i; 203 #ifdef DEVICE_POLLING 204 const int polling = 1; 205 #else 206 const int polling = 0; 207 #endif 208 209 mtx_lock(&netisr_mtx); 210 do { 211 bits = atomic_readandclear_int(&netisr); 212 if (bits == 0) 213 break; 214 while ((i = ffs(bits)) != 0) { 215 isrstat.isrs_swi_count++; 216 i--; 217 bits &= ~(1 << i); 218 ni = &netisrs[i]; 219 if (ni->ni_handler == NULL) { 220 printf("swi_net: unregistered isr %d.\n", i); 221 continue; 222 } 223 if (ni->ni_queue == NULL) 224 ni->ni_handler(NULL); 225 else 226 for (;;) { 227 IF_DEQUEUE(ni->ni_queue, m); 228 if (m == NULL) 229 break; 230 ni->ni_handler(m); 231 } 232 } 233 } while (polling); 234 mtx_unlock(&netisr_mtx); 235 } 236 237 static void 238 start_netisr(void *dummy) 239 { 240 241 mtx_init(&netisr_mtx, "netisr lock", NULL, MTX_DEF); 242 if (swi_add(NULL, "net", swi_net, NULL, SWI_NET, 0, &net_ih)) 243 panic("start_netisr"); 244 } 245 SYSINIT(start_netisr, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_netisr, NULL) 246