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 /* 57 * XXX this is a temporary measure to allow folks to 58 * XXX disable Giant locking in the network code without 59 * XXX recompiling--in case of problems. 60 */ 61 int debug_mpsafenet = 0; 62 TUNABLE_INT("debug.mpsafenet", &debug_mpsafenet); 63 SYSCTL_INT(_debug, OID_AUTO, mpsafenet, CTLFLAG_RD, &debug_mpsafenet, 0, 64 "Enable/disable MPSAFE network support"); 65 66 volatile unsigned int netisr; /* scheduling bits for network */ 67 68 struct netisr { 69 netisr_t *ni_handler; 70 struct ifqueue *ni_queue; 71 int ni_flags; 72 } netisrs[32]; 73 74 static void *net_ih; 75 76 void 77 legacy_setsoftnet(void) 78 { 79 swi_sched(net_ih, 0); 80 } 81 82 void 83 netisr_register(int num, netisr_t *handler, struct ifqueue *inq, int flags) 84 { 85 86 KASSERT(!(num < 0 || num >= (sizeof(netisrs)/sizeof(*netisrs))), 87 ("bad isr %d", num)); 88 netisrs[num].ni_handler = handler; 89 netisrs[num].ni_queue = inq; 90 if ((flags & NETISR_MPSAFE) && !debug_mpsafenet) 91 flags &= ~NETISR_MPSAFE; 92 netisrs[num].ni_flags = flags; 93 } 94 95 void 96 netisr_unregister(int num) 97 { 98 struct netisr *ni; 99 100 KASSERT(!(num < 0 || num >= (sizeof(netisrs)/sizeof(*netisrs))), 101 ("bad isr %d", num)); 102 ni = &netisrs[num]; 103 ni->ni_handler = NULL; 104 if (ni->ni_queue != NULL) 105 IF_DRAIN(ni->ni_queue); 106 } 107 108 struct isrstat { 109 int isrs_count; /* dispatch count */ 110 int isrs_directed; /* ...directly dispatched */ 111 int isrs_deferred; /* ...queued instead */ 112 int isrs_queued; /* intentionally queueued */ 113 int isrs_drop; /* dropped 'cuz no handler */ 114 int isrs_swi_count; /* swi_net handlers called */ 115 }; 116 static struct isrstat isrstat; 117 118 SYSCTL_NODE(_net, OID_AUTO, isr, CTLFLAG_RW, 0, "netisr counters"); 119 120 static int netisr_enable = 0; 121 SYSCTL_INT(_net_isr, OID_AUTO, enable, CTLFLAG_RW, 122 &netisr_enable, 0, "enable direct dispatch"); 123 TUNABLE_INT("net.isr.enable", &netisr_enable); 124 125 SYSCTL_INT(_net_isr, OID_AUTO, count, CTLFLAG_RD, 126 &isrstat.isrs_count, 0, ""); 127 SYSCTL_INT(_net_isr, OID_AUTO, directed, CTLFLAG_RD, 128 &isrstat.isrs_directed, 0, ""); 129 SYSCTL_INT(_net_isr, OID_AUTO, deferred, CTLFLAG_RD, 130 &isrstat.isrs_deferred, 0, ""); 131 SYSCTL_INT(_net_isr, OID_AUTO, queued, CTLFLAG_RD, 132 &isrstat.isrs_queued, 0, ""); 133 SYSCTL_INT(_net_isr, OID_AUTO, drop, CTLFLAG_RD, 134 &isrstat.isrs_drop, 0, ""); 135 SYSCTL_INT(_net_isr, OID_AUTO, swi_count, CTLFLAG_RD, 136 &isrstat.isrs_swi_count, 0, ""); 137 138 /* 139 * Process all packets currently present in a netisr queue. Used to 140 * drain an existing set of packets waiting for processing when we 141 * begin direct dispatch, to avoid processing packets out of order. 142 */ 143 static void 144 netisr_processqueue(struct netisr *ni) 145 { 146 struct mbuf *m; 147 148 for (;;) { 149 IF_DEQUEUE(ni->ni_queue, m); 150 if (m == NULL) 151 break; 152 ni->ni_handler(m); 153 } 154 } 155 156 /* 157 * Call the netisr directly instead of queueing the packet, if possible. 158 */ 159 void 160 netisr_dispatch(int num, struct mbuf *m) 161 { 162 struct netisr *ni; 163 164 isrstat.isrs_count++; /* XXX redundant */ 165 KASSERT(!(num < 0 || num >= (sizeof(netisrs)/sizeof(*netisrs))), 166 ("bad isr %d", num)); 167 ni = &netisrs[num]; 168 if (ni->ni_queue == NULL) { 169 isrstat.isrs_drop++; 170 m_freem(m); 171 return; 172 } 173 /* 174 * Do direct dispatch only for MPSAFE netisrs (and 175 * only when enabled). Note that when a netisr is 176 * marked MPSAFE we permit multiple concurrent instances 177 * to run. We guarantee only the order in which 178 * packets are processed for each "dispatch point" in 179 * the system (i.e. call to netisr_dispatch or 180 * netisr_queue). This insures ordering of packets 181 * from an interface but does not guarantee ordering 182 * between multiple places in the system (e.g. IP 183 * dispatched from interfaces vs. IP queued from IPSec). 184 */ 185 if (netisr_enable && (ni->ni_flags & NETISR_MPSAFE)) { 186 isrstat.isrs_directed++; 187 /* 188 * NB: We used to drain the queue before handling 189 * the packet but now do not. Doing so here will 190 * not preserve ordering so instead we fallback to 191 * guaranteeing order only from dispatch points 192 * in the system (see above). 193 */ 194 ni->ni_handler(m); 195 } else { 196 isrstat.isrs_deferred++; 197 if (IF_HANDOFF(ni->ni_queue, m, NULL)) 198 schednetisr(num); 199 } 200 } 201 202 /* 203 * Same as above, but always queue. 204 * This is either used in places where we are not confident that 205 * direct dispatch is possible, or where queueing is required. 206 */ 207 int 208 netisr_queue(int num, struct mbuf *m) 209 { 210 struct netisr *ni; 211 212 KASSERT(!(num < 0 || num >= (sizeof(netisrs)/sizeof(*netisrs))), 213 ("bad isr %d", num)); 214 ni = &netisrs[num]; 215 if (ni->ni_queue == NULL) { 216 isrstat.isrs_drop++; 217 m_freem(m); 218 return (1); 219 } 220 isrstat.isrs_queued++; 221 if (!IF_HANDOFF(ni->ni_queue, m, NULL)) 222 return (0); 223 schednetisr(num); 224 return (1); 225 } 226 227 static void 228 swi_net(void *dummy) 229 { 230 struct netisr *ni; 231 u_int bits; 232 int i; 233 #ifdef DEVICE_POLLING 234 const int polling = 1; 235 #else 236 const int polling = 0; 237 #endif 238 239 do { 240 bits = atomic_readandclear_int(&netisr); 241 if (bits == 0) 242 break; 243 while ((i = ffs(bits)) != 0) { 244 isrstat.isrs_swi_count++; 245 i--; 246 bits &= ~(1 << i); 247 ni = &netisrs[i]; 248 if (ni->ni_handler == NULL) { 249 printf("swi_net: unregistered isr %d.\n", i); 250 continue; 251 } 252 if ((ni->ni_flags & NETISR_MPSAFE) == 0) { 253 mtx_lock(&Giant); 254 if (ni->ni_queue == NULL) 255 ni->ni_handler(NULL); 256 else 257 netisr_processqueue(ni); 258 mtx_unlock(&Giant); 259 } else { 260 if (ni->ni_queue == NULL) 261 ni->ni_handler(NULL); 262 else 263 netisr_processqueue(ni); 264 } 265 } 266 } while (polling); 267 } 268 269 static void 270 start_netisr(void *dummy) 271 { 272 273 if (swi_add(NULL, "net", swi_net, NULL, SWI_NET, INTR_MPSAFE, &net_ih)) 274 panic("start_netisr"); 275 } 276 SYSINIT(start_netisr, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_netisr, NULL) 277