1 /* $NetBSD: ndbootd-bpf.c,v 1.8 2004/12/01 23:18:20 christos Exp $ */ 2 3 /* ndbootd-bpf.c - the Sun Network Disk (nd) daemon BPF component: */ 4 5 /* 6 * Copyright (c) 2001 Matthew Fredette. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by Matthew Fredette. 19 * 4. The name of Matthew Fredette may not be used to endorse or promote 20 * products derived from this software without specific prior written 21 * permission. 22 * 23 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED 24 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF 25 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 26 */ 27 28 /* <<Header: /data/home/fredette/project/THE-WEIGHT-CVS/ndbootd/config/ndbootd-bpf.c,v 1.4 2001/05/23 02:35:49 fredette Exp >> */ 29 30 /* 31 * <<Log: ndbootd-bpf.c,v >> 32 * Revision 1.4 2001/05/23 02:35:49 fredette 33 * Changed many debugging printfs to compile quietly on the 34 * alpha. Patch from Andrew Brown <atatat (at) atatdot.net>. 35 * 36 * Revision 1.3 2001/05/22 13:13:24 fredette 37 * Ran indent(1) with NetBSD's KNF-approximating profile. 38 * 39 * Revision 1.2 2001/05/09 20:50:46 fredette 40 * Removed an unnecessary comment. 41 * 42 * Revision 1.1 2001/01/29 15:12:13 fredette 43 * Added. 44 * 45 */ 46 47 #include <sys/cdefs.h> 48 #if o 49 static const char _ndbootd_bpf_c_rcsid[] = "<<Id: ndbootd-bpf.c,v 1.4 2001/05/23 02:35:49 fredette Exp >>"; 50 #else 51 __RCSID("$NetBSD: ndbootd-bpf.c,v 1.8 2004/12/01 23:18:20 christos Exp $"); 52 #endif 53 54 /* includes: */ 55 #include <sys/poll.h> 56 #include <net/bpf.h> 57 #include <paths.h> 58 59 /* structures: */ 60 struct _ndbootd_interface_bpf { 61 62 /* the size of the packet buffer for the interface: */ 63 size_t _ndbootd_interface_bpf_buffer_size; 64 65 /* the packet buffer for the interface: */ 66 char *_ndbootd_interface_bpf_buffer; 67 68 /* the next offset within the packet buffer, and the end of the data 69 * in the packet buffer: */ 70 size_t _ndbootd_interface_bpf_buffer_offset; 71 size_t _ndbootd_interface_bpf_buffer_end; 72 }; 73 74 /* the BPF program to capture ND packets: */ 75 static struct bpf_insn ndboot_bpf_filter[] = { 76 77 /* drop this packet if its ethertype isn't ETHERTYPE_IP: */ 78 BPF_STMT(BPF_LD + BPF_H + BPF_ABS, NDBOOTD_OFFSETOF(struct ether_header, ether_type)), 79 BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_IP, 0, 9), 80 81 /* drop this packet if its IP protocol isn't IPPROTO_ND: */ 82 BPF_STMT(BPF_LD + BPF_B + BPF_ABS, sizeof(struct ether_header) + NDBOOTD_OFFSETOF(struct ip, ip_p)), 83 BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_ND, 0, 7), 84 85 /* drop this packet if it's a fragment: */ 86 BPF_STMT(BPF_LD + BPF_H + BPF_ABS, sizeof(struct ether_header) + NDBOOTD_OFFSETOF(struct ip, ip_off)), 87 BPF_JUMP(BPF_JMP + BPF_JSET + BPF_K, 0x3fff, 5, 0), 88 89 /* drop this packet if it is carrying data (we only want requests, 90 * which have no data): */ 91 BPF_STMT(BPF_LD + BPF_H + BPF_ABS, sizeof(struct ether_header) + NDBOOTD_OFFSETOF(struct ip, ip_len)), 92 BPF_STMT(BPF_LDX + BPF_B + BPF_MSH, sizeof(struct ether_header)), 93 BPF_STMT(BPF_ALU + BPF_SUB + BPF_X, 0), 94 BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, sizeof(struct ndboot_packet), 0, 1), 95 96 /* accept this packet: */ 97 BPF_STMT(BPF_RET + BPF_K, (u_int) -1), 98 99 /* drop this packet: */ 100 BPF_STMT(BPF_RET + BPF_K, 0), 101 }; 102 103 /* this opens a raw socket using BPF. */ 104 int 105 ndbootd_raw_open(struct ndbootd_interface * interface) 106 { 107 int network_fd; 108 int saved_errno; 109 u_int bufsize; 110 u_int bpf_opt; 111 struct bpf_version version; 112 u_int packet_buffer_size; 113 struct bpf_program program; 114 struct _ndbootd_interface_bpf *interface_bpf; 115 const char *dev_bpf_filename = _PATH_BPF; 116 117 /* loop trying to open the /dev/bpf device: */ 118 if ((network_fd = open(dev_bpf_filename, O_RDWR)) < 0) { 119 /* we have failed: */ 120 _NDBOOTD_DEBUG((fp, "bpf: failed to open %s: %s", dev_bpf_filename, strerror(errno))); 121 return (-1); 122 } 123 _NDBOOTD_DEBUG((fp, "bpf: opened %s", dev_bpf_filename)); 124 125 /* this macro helps in closing the BPF socket on error: */ 126 #define _NDBOOTD_RAW_OPEN_ERROR(x) saved_errno = errno; x; errno = saved_errno 127 128 /* check the BPF version: */ 129 if (ioctl(network_fd, BIOCVERSION, &version) < 0) { 130 _NDBOOTD_DEBUG((fp, "bpf: failed to get the BPF version on %s: %s", 131 dev_bpf_filename, strerror(errno))); 132 _NDBOOTD_RAW_OPEN_ERROR(close(network_fd)); 133 return (-1); 134 } 135 if (version.bv_major != BPF_MAJOR_VERSION 136 || version.bv_minor < BPF_MINOR_VERSION) { 137 _NDBOOTD_DEBUG((fp, "bpf: kernel BPF version is %d.%d, my BPF version is %d.%d", 138 version.bv_major, version.bv_minor, 139 BPF_MAJOR_VERSION, BPF_MINOR_VERSION)); 140 close(network_fd); 141 errno = ENXIO; 142 return (-1); 143 } 144 /* put the BPF device into immediate mode: */ 145 bpf_opt = TRUE; 146 if (ioctl(network_fd, BIOCIMMEDIATE, &bpf_opt) < 0) { 147 _NDBOOTD_DEBUG((fp, "bpf: failed to put %s into immediate mode: %s", 148 dev_bpf_filename, strerror(errno))); 149 _NDBOOTD_RAW_OPEN_ERROR(close(network_fd)); 150 return (-1); 151 } 152 /* set a reasonable sized buffer for the BPF device */ 153 bufsize = 32768; 154 if (ioctl(network_fd, BIOCSBLEN, &bufsize) < 0) { 155 _NDBOOTD_DEBUG((fp, "bpf: failed set buffer size to %d: %s", 156 bufsize, strerror(errno))); 157 } 158 /* tell the BPF device we're providing complete Ethernet headers: */ 159 bpf_opt = TRUE; 160 if (ioctl(network_fd, BIOCSHDRCMPLT, &bpf_opt) < 0) { 161 _NDBOOTD_DEBUG((fp, "bpf: failed to put %s into complete-headers mode: %s", 162 dev_bpf_filename, strerror(errno))); 163 _NDBOOTD_RAW_OPEN_ERROR(close(network_fd)); 164 return (-1); 165 } 166 /* point the BPF device at the interface we're using: */ 167 if (ioctl(network_fd, BIOCSETIF, interface->ndbootd_interface_ifreq) < 0) { 168 _NDBOOTD_DEBUG((fp, "bpf: failed to point BPF socket at %s: %s", 169 interface->ndbootd_interface_ifreq->ifr_name, strerror(errno))); 170 saved_errno = errno; 171 close(network_fd); 172 errno = saved_errno; 173 return (-1); 174 } 175 /* set the filter on the BPF device: */ 176 program.bf_len = sizeof(ndboot_bpf_filter) / sizeof(ndboot_bpf_filter[0]); 177 program.bf_insns = ndboot_bpf_filter; 178 if (ioctl(network_fd, BIOCSETF, &program) < 0) { 179 _NDBOOTD_DEBUG((fp, "bpf: failed to set the filter on %s: %s", 180 dev_bpf_filename, strerror(errno))); 181 _NDBOOTD_RAW_OPEN_ERROR(close(network_fd)); 182 return (-1); 183 } 184 /* get the BPF read buffer size: */ 185 if (ioctl(network_fd, BIOCGBLEN, &packet_buffer_size) < 0) { 186 _NDBOOTD_DEBUG((fp, "bpf: failed to read the buffer size for %s: %s", 187 dev_bpf_filename, strerror(errno))); 188 _NDBOOTD_RAW_OPEN_ERROR(close(network_fd)); 189 return (-1); 190 } 191 _NDBOOTD_DEBUG((fp, "bpf: buffer size for %s is %u", 192 dev_bpf_filename, packet_buffer_size)); 193 194 /* allocate our private interface information and we're done: */ 195 interface->ndbootd_interface_fd = network_fd; 196 interface_bpf = ndbootd_new0(struct _ndbootd_interface_bpf, 1); 197 interface_bpf->_ndbootd_interface_bpf_buffer_size = packet_buffer_size; 198 interface_bpf->_ndbootd_interface_bpf_buffer = ndbootd_new(char, packet_buffer_size); 199 interface->_ndbootd_interface_raw_private = interface_bpf; 200 return (0); 201 #undef _NDBOOTD_RAW_OPEN_ERROR 202 } 203 204 /* this reads a raw packet: */ 205 int 206 ndbootd_raw_read(struct ndbootd_interface * interface, void *packet_buffer, size_t packet_buffer_size) 207 { 208 struct _ndbootd_interface_bpf *interface_bpf; 209 ssize_t buffer_end; 210 struct bpf_hdr the_bpf_header; 211 struct pollfd set[1]; 212 213 /* recover our state: */ 214 interface_bpf = (struct _ndbootd_interface_bpf *) interface->_ndbootd_interface_raw_private; 215 216 /* loop until we have something to return: */ 217 set[0].fd = interface->ndbootd_interface_fd; 218 set[0].events = POLLIN; 219 for (;;) { 220 221 /* if the buffer is empty, fill it: */ 222 if (interface_bpf->_ndbootd_interface_bpf_buffer_offset 223 >= interface_bpf->_ndbootd_interface_bpf_buffer_end) { 224 225 /* poll on the BPF socket: */ 226 _NDBOOTD_DEBUG((fp, "bpf: calling poll")); 227 switch (poll(set, 1, INFTIM)) { 228 case 0: 229 _NDBOOTD_DEBUG((fp, "bpf: poll returned zero")); 230 continue; 231 case 1: 232 break; 233 default: 234 if (errno == EINTR) { 235 _NDBOOTD_DEBUG((fp, "bpf: poll got EINTR")); 236 continue; 237 } 238 _NDBOOTD_DEBUG((fp, "bpf: poll failed: %s", strerror(errno))); 239 return (-1); 240 } 241 assert(set[0].revents & POLLIN); 242 243 /* read the BPF socket: */ 244 _NDBOOTD_DEBUG((fp, "bpf: calling read")); 245 buffer_end = read(interface->ndbootd_interface_fd, 246 interface_bpf->_ndbootd_interface_bpf_buffer, 247 interface_bpf->_ndbootd_interface_bpf_buffer_size); 248 if (buffer_end <= 0) { 249 _NDBOOTD_DEBUG((fp, "bpf: failed to read packets: %s", strerror(errno))); 250 return (-1); 251 } 252 _NDBOOTD_DEBUG((fp, "bpf: read %ld bytes of packets", (long) buffer_end)); 253 interface_bpf->_ndbootd_interface_bpf_buffer_offset = 0; 254 interface_bpf->_ndbootd_interface_bpf_buffer_end = buffer_end; 255 } 256 /* if there's not enough for a BPF header, flush the buffer: */ 257 if ((interface_bpf->_ndbootd_interface_bpf_buffer_offset 258 + sizeof(the_bpf_header)) 259 > interface_bpf->_ndbootd_interface_bpf_buffer_end) { 260 _NDBOOTD_DEBUG((fp, "bpf: flushed garbage BPF header bytes")); 261 interface_bpf->_ndbootd_interface_bpf_buffer_end = 0; 262 continue; 263 } 264 /* get the BPF header and check it: */ 265 memcpy(&the_bpf_header, 266 interface_bpf->_ndbootd_interface_bpf_buffer 267 + interface_bpf->_ndbootd_interface_bpf_buffer_offset, 268 sizeof(the_bpf_header)); 269 interface_bpf->_ndbootd_interface_bpf_buffer_offset += the_bpf_header.bh_hdrlen; 270 271 /* if we're missing some part of the packet: */ 272 if (the_bpf_header.bh_caplen != the_bpf_header.bh_datalen 273 || ((interface_bpf->_ndbootd_interface_bpf_buffer_offset + the_bpf_header.bh_datalen) 274 > interface_bpf->_ndbootd_interface_bpf_buffer_end)) { 275 _NDBOOTD_DEBUG((fp, "bpf: flushed truncated BPF packet")); 276 interface_bpf->_ndbootd_interface_bpf_buffer_offset += the_bpf_header.bh_datalen; 277 continue; 278 } 279 /* silently ignore packets that don't even have Ethernet 280 * headers, and those packets that we transmitted: */ 281 if (the_bpf_header.bh_datalen < sizeof(struct ether_header) 282 || !memcmp(((struct ether_header *) 283 (interface_bpf->_ndbootd_interface_bpf_buffer 284 + interface_bpf->_ndbootd_interface_bpf_buffer_offset))->ether_shost, 285 interface->ndbootd_interface_ether, 286 ETHER_ADDR_LEN)) { 287 /* silently ignore packets from us: */ 288 interface_bpf->_ndbootd_interface_bpf_buffer_offset += the_bpf_header.bh_datalen; 289 continue; 290 } 291 /* if the caller hasn't provided a large enough buffer: */ 292 if (packet_buffer_size < the_bpf_header.bh_datalen) { 293 errno = EIO; 294 interface_bpf->_ndbootd_interface_bpf_buffer_offset += the_bpf_header.bh_datalen; 295 return (-1); 296 } 297 /* return this captured packet to the user: */ 298 memcpy(packet_buffer, 299 interface_bpf->_ndbootd_interface_bpf_buffer 300 + interface_bpf->_ndbootd_interface_bpf_buffer_offset, 301 the_bpf_header.bh_datalen); 302 interface_bpf->_ndbootd_interface_bpf_buffer_offset += the_bpf_header.bh_datalen; 303 return (the_bpf_header.bh_datalen); 304 } 305 /* NOTREACHED */ 306 } 307 308 /* this writes a raw packet: */ 309 int 310 ndbootd_raw_write(struct ndbootd_interface * interface, void *packet_buffer, size_t packet_buffer_size) 311 { 312 return (write(interface->ndbootd_interface_fd, packet_buffer, packet_buffer_size)); 313 } 314
Indexes created Sun Sep 21 20:09:37 GMT 2025