/* * This code is derived from code formerly in pcap-dlpi.c, originally * contributed by Atanu Ghosh (atanu@cs.ucl.ac.uk), University College * London, and subsequently modified by Guy Harris (guy@alum.mit.edu), * Mark Pizzolato , * Mark C. Brown (mbrown@hp.com), and Sagun Shakya . */ /* * This file contains dlpi/libdlpi related common functions used * by pcap-[dlpi,libdlpi].c. */ #ifndef lint static const char rcsid[] _U_ = "@(#) $Header: /tcpdump/master/libpcap/dlpisubs.c,v 1.1.2.2 2008-04-04 19:39:05 guy Exp $ (LBL)"; #endif #ifdef HAVE_CONFIG_H #include "config.h" #endif #ifdef HAVE_SYS_BUFMOD_H /* * Size of a bufmod chunk to pass upstream; that appears to be the * biggest value to which you can set it, and setting it to that value * (which is bigger than what appears to be the Solaris default of 8192) * reduces the number of packet drops. */ #define CHUNKSIZE 65536 /* * Size of the buffer to allocate for packet data we read; it must be * large enough to hold a chunk. */ #define PKTBUFSIZE CHUNKSIZE #else /* HAVE_SYS_BUFMOD_H */ /* * Size of the buffer to allocate for packet data we read; this is * what the value used to be - there's no particular reason why it * should be tied to MAXDLBUF, but we'll leave it as this for now. */ #define PKTBUFSIZE (MAXDLBUF * sizeof(bpf_u_int32)) #endif #include #include #ifdef HAVE_SYS_BUFMOD_H #include #endif #include #include #include #include #include #include #include #include #include #include "pcap-int.h" #include "dlpisubs.h" static void pcap_stream_err(const char *, int, char *); /* * Get the packet statistics. */ int pcap_stats_dlpi(pcap_t *p, struct pcap_stat *ps) { /* * "ps_recv" counts packets handed to the filter, not packets * that passed the filter. As filtering is done in userland, * this would not include packets dropped because we ran out * of buffer space; in order to make this more like other * platforms (Linux 2.4 and later, BSDs with BPF), where the * "packets received" count includes packets received but dropped * due to running out of buffer space, and to keep from confusing * applications that, for example, compute packet drop percentages, * we also make it count packets dropped by "bufmod" (otherwise we * might run the risk of the packet drop count being bigger than * the received-packet count). * * "ps_drop" counts packets dropped by "bufmod" because of * flow control requirements or resource exhaustion; it doesn't * count packets dropped by the interface driver, or packets * dropped upstream. As filtering is done in userland, it counts * packets regardless of whether they would've passed the filter. * * These statistics don't include packets not yet read from * the kernel by libpcap, but they may include packets not * yet read from libpcap by the application. */ *ps = p->md.stat; /* * Add in the drop count, as per the above comment. */ ps->ps_recv += ps->ps_drop; return (0); } /* * Loop through the packets and call the callback for each packet. * Return the number of packets read. */ int pcap_process_pkts(pcap_t *p, pcap_handler callback, u_char *user, int count, u_char *bufp, int len) { int n, caplen, origlen; u_char *ep, *pk; struct pcap_pkthdr pkthdr; #ifdef HAVE_SYS_BUFMOD_H struct sb_hdr *sbp; #ifdef LBL_ALIGN struct sb_hdr sbhdr; #endif #endif /* Loop through packets */ ep = bufp + len; n = 0; #ifdef HAVE_SYS_BUFMOD_H while (bufp < ep) { /* * Has "pcap_breakloop()" been called? * If so, return immediately - if we haven't read any * packets, clear the flag and return -2 to indicate * that we were told to break out of the loop, otherwise * leave the flag set, so that the *next* call will break * out of the loop without having read any packets, and * return the number of packets we've processed so far. */ if (p->break_loop) { if (n == 0) { p->break_loop = 0; return (-2); } else { p->bp = bufp; p->cc = ep - bufp; return (n); } } #ifdef LBL_ALIGN if ((long)bufp & 3) { sbp = &sbhdr; memcpy(sbp, bufp, sizeof(*sbp)); } else #endif sbp = (struct sb_hdr *)bufp; p->md.stat.ps_drop = sbp->sbh_drops; pk = bufp + sizeof(*sbp); bufp += sbp->sbh_totlen; origlen = sbp->sbh_origlen; caplen = sbp->sbh_msglen; #else origlen = len; caplen = min(p->snapshot, len); pk = bufp; bufp += caplen; #endif ++p->md.stat.ps_recv; if (bpf_filter(p->fcode.bf_insns, pk, origlen, caplen)) { #ifdef HAVE_SYS_BUFMOD_H pkthdr.ts.tv_sec = sbp->sbh_timestamp.tv_sec; pkthdr.ts.tv_usec = sbp->sbh_timestamp.tv_usec; #else (void) gettimeofday(&pkthdr.ts, NULL); #endif pkthdr.len = origlen; pkthdr.caplen = caplen; /* Insure caplen does not exceed snapshot */ if (pkthdr.caplen > p->snapshot) pkthdr.caplen = p->snapshot; (*callback)(user, &pkthdr, pk); if (++n >= count && count >= 0) { p->cc = ep - bufp; p->bp = bufp; return (n); } } #ifdef HAVE_SYS_BUFMOD_H } #endif p->cc = 0; return (n); } /* * Process the mac type. Returns -1 if no matching mac type found, otherwise 0. */ int pcap_process_mactype(pcap_t *p, u_int mactype) { int retv = 0; switch (mactype) { case DL_CSMACD: case DL_ETHER: p->linktype = DLT_EN10MB; p->offset = 2; /* * This is (presumably) a real Ethernet capture; give it a * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so * that an application can let you choose it, in case you're * capturing DOCSIS traffic that a Cisco Cable Modem * Termination System is putting out onto an Ethernet (it * doesn't put an Ethernet header onto the wire, it puts raw * DOCSIS frames out on the wire inside the low-level * Ethernet framing). */ p->dlt_list = (u_int *)malloc(sizeof(u_int) * 2); /* * If that fails, just leave the list empty. */ if (p->dlt_list != NULL) { p->dlt_list[0] = DLT_EN10MB; p->dlt_list[1] = DLT_DOCSIS; p->dlt_count = 2; } break; case DL_FDDI: p->linktype = DLT_FDDI; p->offset = 3; break; case DL_TPR: /* XXX - what about DL_TPB? Is that Token Bus? */ p->linktype = DLT_IEEE802; p->offset = 2; break; #ifdef HAVE_SOLARIS case DL_IPATM: p->linktype = DLT_SUNATM; p->offset = 0; /* works for LANE and LLC encapsulation */ break; #endif default: snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "unknown mactype %u", mactype); retv = -1; } return (retv); } #ifdef HAVE_SYS_BUFMOD_H /* * Push and configure the buffer module. Returns -1 for error, otherwise 0. */ int pcap_conf_bufmod(pcap_t *p, int snaplen, int timeout) { int retv = 0; bpf_u_int32 ss, chunksize; /* Non-standard call to get the data nicely buffered. */ if (ioctl(p->fd, I_PUSH, "bufmod") != 0) { pcap_stream_err("I_PUSH bufmod", errno, p->errbuf); retv = -1; } ss = snaplen; if (ss > 0 && strioctl(p->fd, SBIOCSSNAP, sizeof(ss), (char *)&ss) != 0) { pcap_stream_err("SBIOCSSNAP", errno, p->errbuf); retv = -1; } /* Set up the bufmod timeout. */ if (timeout != 0) { struct timeval to; to.tv_sec = timeout / 1000; to.tv_usec = (timeout * 1000) % 1000000; if (strioctl(p->fd, SBIOCSTIME, sizeof(to), (char *)&to) != 0) { pcap_stream_err("SBIOCSTIME", errno, p->errbuf); retv = -1; } } /* Set the chunk length. */ chunksize = CHUNKSIZE; if (strioctl(p->fd, SBIOCSCHUNK, sizeof(chunksize), (char *)&chunksize) != 0) { pcap_stream_err("SBIOCSCHUNKP", errno, p->errbuf); retv = -1; } return (retv); } #endif /* HAVE_SYS_BUFMOD_H */ /* * Allocate data buffer. Returns -1 if memory allocation fails, else 0. */ int pcap_alloc_databuf(pcap_t *p) { p->bufsize = PKTBUFSIZE; p->buffer = (u_char *)malloc(p->bufsize + p->offset); if (p->buffer == NULL) { strlcpy(p->errbuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE); return (-1); } return (0); } /* * Issue a STREAMS I_STR ioctl. Returns -1 on error, otherwise * length of returned data on success. */ int strioctl(int fd, int cmd, int len, char *dp) { struct strioctl str; int retv; str.ic_cmd = cmd; str.ic_timout = -1; str.ic_len = len; str.ic_dp = dp; if ((retv = ioctl(fd, I_STR, &str)) < 0) return (retv); return (str.ic_len); } /* * Write stream error message to errbuf. */ static void pcap_stream_err(const char *func, int err, char *errbuf) { snprintf(errbuf, PCAP_ERRBUF_SIZE, "%s: %s", func, pcap_strerror(err)); }