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3 * for Software Science (CSS).
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41 * from: @(#)bpf.c 8.1 (Berkeley) 6/4/93
43 * From: Utah Hdr: bpf.c 3.1 92/07/06
44 * Author: Jeff Forys, University of Utah CSS
46 * @(#)bpf.c 8.1 (Berkeley) 6/4/93
47 * $FreeBSD: src/libexec/rbootd/bpf.c,v 1.10 1999/08/28 00:09:44 peter Exp $
50 #include <sys/param.h>
51 #include <sys/ioctl.h>
52 #include <sys/socket.h>
67 #include "pathnames.h"
69 static int BpfFd = -1;
70 static unsigned BpfLen = 0;
71 static u_int8_t *BpfPkt = NULL;
74 ** BpfOpen -- Open and initialize a BPF device.
80 ** File descriptor of opened BPF device (for select() etc).
83 ** If an error is encountered, the program terminates here.
93 * Open the first available BPF device.
96 (void) sprintf(bpfdev, _PATH_BPF, n++);
97 BpfFd = open(bpfdev, O_RDWR);
98 } while (BpfFd < 0 && (errno == EBUSY || errno == EPERM));
101 syslog(LOG_ERR, "bpf: no available devices: %m");
106 * Set interface name for bpf device, get data link layer
107 * type and make sure it's type Ethernet.
109 (void) strncpy(ifr.ifr_name, IntfName, sizeof(ifr.ifr_name));
110 if (ioctl(BpfFd, BIOCSETIF, (caddr_t)&ifr) < 0) {
111 syslog(LOG_ERR, "bpf: ioctl(BIOCSETIF,%s): %m", IntfName);
116 * Make sure we are dealing with an Ethernet device.
118 if (ioctl(BpfFd, BIOCGDLT, (caddr_t)&n) < 0) {
119 syslog(LOG_ERR, "bpf: ioctl(BIOCGDLT): %m");
122 if (n != DLT_EN10MB) {
123 syslog(LOG_ERR,"bpf: %s: data-link type %d unsupported",
129 * On read(), return packets immediately (do not buffer them).
132 if (ioctl(BpfFd, BIOCIMMEDIATE, (caddr_t)&n) < 0) {
133 syslog(LOG_ERR, "bpf: ioctl(BIOCIMMEDIATE): %m");
138 * Try to enable the chip/driver's multicast address filter to
139 * grab our RMP address. If this fails, try promiscuous mode.
140 * If this fails, there's no way we are going to get any RMP
141 * packets so just exit here.
144 ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2;
146 ifr.ifr_addr.sa_family = AF_UNSPEC;
147 memmove((char *)&ifr.ifr_addr.sa_data[0], &RmpMcastAddr[0], RMP_ADDRLEN);
148 if (ioctl(BpfFd, BIOCPROMISC, (caddr_t)0) < 0) {
149 syslog(LOG_ERR, "bpf: can't set promiscuous mode: %m");
154 * Ask BPF how much buffer space it requires and allocate one.
156 if (ioctl(BpfFd, BIOCGBLEN, (caddr_t)&BpfLen) < 0) {
157 syslog(LOG_ERR, "bpf: ioctl(BIOCGBLEN): %m");
161 BpfPkt = (u_int8_t *)malloc(BpfLen);
163 if (BpfPkt == NULL) {
164 syslog(LOG_ERR, "bpf: out of memory (%u bytes for bpfpkt)",
170 * Write a little program to snarf RMP Boot packets and stuff
171 * it down BPF's throat (i.e. set up the packet filter).
174 #define RMP ((struct rmp_packet *)0)
175 static struct bpf_insn bpf_insn[] = {
176 { BPF_LD|BPF_B|BPF_ABS, 0, 0, (long)&RMP->hp_llc.dsap },
177 { BPF_JMP|BPF_JEQ|BPF_K, 0, 5, IEEE_DSAP_HP },
178 { BPF_LD|BPF_H|BPF_ABS, 0, 0, (long)&RMP->hp_llc.cntrl },
179 { BPF_JMP|BPF_JEQ|BPF_K, 0, 3, IEEE_CNTL_HP },
180 { BPF_LD|BPF_H|BPF_ABS, 0, 0, (long)&RMP->hp_llc.dxsap },
181 { BPF_JMP|BPF_JEQ|BPF_K, 0, 1, HPEXT_DXSAP },
182 { BPF_RET|BPF_K, 0, 0, RMP_MAX_PACKET },
183 { BPF_RET|BPF_K, 0, 0, 0x0 }
186 static struct bpf_program bpf_pgm = {
187 sizeof(bpf_insn)/sizeof(bpf_insn[0]), bpf_insn
190 if (ioctl(BpfFd, BIOCSETF, (caddr_t)&bpf_pgm) < 0) {
191 syslog(LOG_ERR, "bpf: ioctl(BIOCSETF): %m");
200 ** BPF GetIntfName -- Return the name of a network interface attached to
201 ** the system, or 0 if none can be found. The interface
202 ** must be configured up; the lowest unit number is
203 ** preferred; loopback is ignored.
206 ** errmsg - if no network interface found, *errmsg explains why.
209 ** A (static) pointer to interface name, or NULL on error.
215 BpfGetIntfName(errmsg)
218 struct ifreq ibuf[8], *ifrp, *ifend, *mp;
223 static char device[sizeof(ifrp->ifr_name)];
224 static char errbuf[128] = "No Error!";
229 if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
230 (void) strcpy(errbuf, "bpf: socket: %m");
233 ifc.ifc_len = sizeof ibuf;
234 ifc.ifc_buf = (caddr_t)ibuf;
237 if (ioctl(fd, OSIOCGIFCONF, (char *)&ifc) < 0 ||
238 ifc.ifc_len < sizeof(struct ifreq)) {
239 (void) strcpy(errbuf, "bpf: ioctl(OSIOCGIFCONF): %m");
243 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 ||
244 ifc.ifc_len < sizeof(struct ifreq)) {
245 (void) strcpy(errbuf, "bpf: ioctl(SIOCGIFCONF): %m");
250 ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len);
254 for (; ifrp < ifend; ++ifrp) {
255 if (ioctl(fd, SIOCGIFFLAGS, (char *)ifrp) < 0) {
256 (void) strcpy(errbuf, "bpf: ioctl(SIOCGIFFLAGS): %m");
261 * If interface is down or this is the loopback interface,
264 if ((ifrp->ifr_flags & IFF_UP) == 0 ||
266 (ifrp->ifr_flags & IFF_LOOPBACK))
268 (strcmp(ifrp->ifr_name, "lo0") == 0))
272 for (cp = ifrp->ifr_name; !isdigit(*cp); ++cp)
283 (void) strcpy(errbuf, "bpf: no interfaces found");
287 (void) strcpy(device, mp->ifr_name);
292 ** BpfRead -- Read packets from a BPF device and fill in `rconn'.
295 ** rconn - filled in with next packet.
296 ** doread - is True if we can issue a read() syscall.
299 ** True if `rconn' contains a new packet, False otherwise.
305 BpfRead(rconn, doread)
309 int datlen, caplen, hdrlen;
310 static u_int8_t *bp = NULL, *ep = NULL;
314 * The read() may block, or it may return one or more packets.
315 * We let the caller decide whether or not we can issue a read().
318 if ((cc = read(BpfFd, (char *)BpfPkt, (int)BpfLen)) < 0) {
319 syslog(LOG_ERR, "bpf: read: %m");
327 #define bhp ((struct bpf_hdr *)bp)
329 * If there is a new packet in the buffer, stuff it into `rconn'
330 * and return a success indication.
333 datlen = bhp->bh_datalen;
334 caplen = bhp->bh_caplen;
335 hdrlen = bhp->bh_hdrlen;
337 if (caplen != datlen)
339 "bpf: short packet dropped (%d of %d bytes)",
341 else if (caplen > sizeof(struct rmp_packet))
342 syslog(LOG_ERR, "bpf: large packet dropped (%d bytes)",
345 rconn->rmplen = caplen;
346 memmove((char *)&rconn->tstamp, (char *)&bhp->bh_tstamp,
347 sizeof(struct timeval));
348 memmove((char *)&rconn->rmp, (char *)bp + hdrlen, caplen);
350 bp += BPF_WORDALIGN(caplen + hdrlen);
359 ** BpfWrite -- Write packet to BPF device.
362 ** rconn - packet to send.
365 ** True if write succeeded, False otherwise.
374 if (write(BpfFd, (char *)&rconn->rmp, rconn->rmplen) < 0) {
375 syslog(LOG_ERR, "write: %s: %m", EnetStr(rconn));
383 ** BpfClose -- Close a BPF device.
399 if (BpfPkt != NULL) {
400 free((char *)BpfPkt);
408 ifr.ifr_addr.sa_len = RMP_ADDRLEN + 2;
410 ifr.ifr_addr.sa_family = AF_UNSPEC;
411 memmove((char *)&ifr.ifr_addr.sa_data[0], &RmpMcastAddr[0], RMP_ADDRLEN);
412 if (ioctl(BpfFd, SIOCDELMULTI, (caddr_t)&ifr) < 0)
413 (void) ioctl(BpfFd, BIOCPROMISC, (caddr_t)0);