/* * pcap-dag.c: Packet capture interface for Endace DAG card. * * The functionality of this code attempts to mimic that of pcap-linux as much * as possible. This code is compiled in several different ways depending on * whether DAG_ONLY and HAVE_DAG_API are defined. If HAVE_DAG_API is not * defined it should not get compiled in, otherwise if DAG_ONLY is defined then * the 'dag_' function calls are renamed to 'pcap_' equivalents. If DAG_ONLY * is not defined then nothing is altered - the dag_ functions will be * called as required from their pcap-linux/bpf equivalents. * * Author: Richard Littin, Sean Irvine ({richard,sean}@reeltwo.com) * * Modifications: * 2003 May - Jesper Peterson * Code shuffled around to suit fad-xxx.c structure * Added atexit() handler to stop DAG if application is too lazy * 2003 September - Koryn Grant * Added support for nonblocking operation. * Added support for processing more than a single packet in pcap_dispatch(). * Fixed bug in loss counter code. * Improved portability of loss counter code (e.g. use UINT_MAX instead of 0xffff). * Removed unused local variables. * Added required headers (ctype.h, limits.h, unistd.h, netinet/in.h). * 2003 October - Koryn Grant * Changed semantics to match those of standard pcap on linux. * - packets rejected by the filter are not counted. */ #ifndef lint static const char rcsid[] _U_ = "@(#) $Header: /tcpdump/master/libpcap/pcap-dag.c,v 1.10.2.4 2003/11/21 10:20:45 guy Exp $ (LBL)"; #endif #ifdef HAVE_CONFIG_H #include "config.h" #endif #include /* optionally get BSD define */ #include #include #include #include "pcap-int.h" #include #include #include #include #include #include struct mbuf; /* Squelch compiler warnings on some platforms for */ struct rtentry; /* declarations in */ #include #include #include #define MIN_DAG_SNAPLEN 12 #define MAX_DAG_SNAPLEN 2040 #define ATM_SNAPLEN 48 typedef struct pcap_dag_node { struct pcap_dag_node *next; pcap_t *p; pid_t pid; } pcap_dag_node_t; static pcap_dag_node_t *pcap_dags = NULL; static int atexit_handler_installed = 0; static const unsigned short endian_test_word = 0x0100; #define IS_BIGENDIAN() (*((unsigned char *)&endian_test_word)) /* * Swap byte ordering of unsigned long long timestamp on a big endian * machine. */ #define SWAP_TS(ull) ((ull & 0xff00000000000000LL) >> 56) | \ ((ull & 0x00ff000000000000LL) >> 40) | \ ((ull & 0x0000ff0000000000LL) >> 24) | \ ((ull & 0x000000ff00000000LL) >> 8) | \ ((ull & 0x00000000ff000000LL) << 8) | \ ((ull & 0x0000000000ff0000LL) << 24) | \ ((ull & 0x000000000000ff00LL) << 40) | \ ((ull & 0x00000000000000ffLL) << 56) #ifdef DAG_ONLY /* This code is required when compiling for a DAG device only. */ #include "pcap-dag.h" /* Replace dag function names with pcap equivalent. */ #define dag_open_live pcap_open_live #define dag_platform_finddevs pcap_platform_finddevs #endif /* DAG_ONLY */ static int dag_setfilter(pcap_t *p, struct bpf_program *fp); static int dag_stats(pcap_t *p, struct pcap_stat *ps); static int dag_set_datalink(pcap_t *p, int dlt); static int dag_get_datalink(pcap_t *p); static int dag_setnonblock(pcap_t *p, int nonblock, char *errbuf); static void delete_pcap_dag(pcap_t *p) { pcap_dag_node_t *curr = NULL, *prev = NULL; for (prev = NULL, curr = pcap_dags; curr != NULL && curr->p != p; prev = curr, curr = curr->next) { /* empty */ } if (curr != NULL && curr->p == p) { if (prev != NULL) { prev->next = curr->next; } else { pcap_dags = curr->next; } } } /* * Performs a graceful shutdown of the DAG card, frees dynamic memory held * in the pcap_t structure, and closes the file descriptor for the DAG card. */ static void dag_platform_close(pcap_t *p) { #ifdef linux if (p != NULL && p->md.device != NULL) { if(dag_stop(p->fd) < 0) fprintf(stderr,"dag_stop %s: %s\n", p->md.device, strerror(errno)); if(dag_close(p->fd) < 0) fprintf(stderr,"dag_close %s: %s\n", p->md.device, strerror(errno)); free(p->md.device); } #else if (p != NULL) { if(dag_stop(p->fd) < 0) fprintf(stderr,"dag_stop: %s\n", strerror(errno)); if(dag_close(p->fd) < 0) fprintf(stderr,"dag_close: %s\n", strerror(errno)); } #endif delete_pcap_dag(p); /* Note: don't need to call close(p->fd) here as dag_close(p->fd) does this. */ } static void atexit_handler(void) { while (pcap_dags != NULL) { if (pcap_dags->pid == getpid()) { dag_platform_close(pcap_dags->p); } else { delete_pcap_dag(pcap_dags->p); } } } static int new_pcap_dag(pcap_t *p) { pcap_dag_node_t *node = NULL; if ((node = malloc(sizeof(pcap_dag_node_t))) == NULL) { return -1; } if (!atexit_handler_installed) { atexit(atexit_handler); atexit_handler_installed = 1; } node->next = pcap_dags; node->p = p; node->pid = getpid(); pcap_dags = node; return 0; } /* * Read at most max_packets from the capture stream and call the callback * for each of them. Returns the number of packets handled, -1 if an * error occured, or -2 if we were told to break out of the loop. */ static int dag_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user) { unsigned int processed = 0; int flags = p->md.dag_offset_flags; unsigned int nonblocking = flags & DAGF_NONBLOCK; for (;;) { /* Get the next bufferful of packets (if necessary). */ while (p->md.dag_mem_top - p->md.dag_mem_bottom < dag_record_size) { /* * Has "pcap_breakloop()" been called? */ if (p->break_loop) { /* * Yes - clear the flag that indicates that * it has, and return -2 to indicate that * we were told to break out of the loop. */ p->break_loop = 0; return -2; } p->md.dag_mem_top = dag_offset(p->fd, &(p->md.dag_mem_bottom), flags); if ((p->md.dag_mem_top - p->md.dag_mem_bottom < dag_record_size) && nonblocking) { /* Pcap is configured to process only available packets, and there aren't any. */ return 0; } } /* Process the packets. */ while (p->md.dag_mem_top - p->md.dag_mem_bottom >= dag_record_size) { unsigned short packet_len = 0; int caplen = 0; struct pcap_pkthdr pcap_header; dag_record_t *header = (dag_record_t *)(p->md.dag_mem_base + p->md.dag_mem_bottom); u_char *dp = ((u_char *)header) + dag_record_size; unsigned short rlen; /* * Has "pcap_breakloop()" been called? */ if (p->break_loop) { /* * Yes - clear the flag that indicates that * it has, and return -2 to indicate that * we were told to break out of the loop. */ p->break_loop = 0; return -2; } if (IS_BIGENDIAN()) { rlen = header->rlen; } else { rlen = ntohs(header->rlen); } p->md.dag_mem_bottom += rlen; switch(header->type) { case TYPE_ATM: packet_len = ATM_SNAPLEN; caplen = ATM_SNAPLEN; dp += 4; break; case TYPE_ETH: if (IS_BIGENDIAN()) { packet_len = header->wlen; } else { packet_len = ntohs(header->wlen); } packet_len -= (p->md.dag_fcs_bits >> 3); caplen = rlen - dag_record_size - 2; if (caplen > packet_len) { caplen = packet_len; } dp += 2; break; case TYPE_HDLC_POS: if (IS_BIGENDIAN()) { packet_len = header->wlen; } else { packet_len = ntohs(header->wlen); } packet_len -= (p->md.dag_fcs_bits >> 3); caplen = rlen - dag_record_size; if (caplen > packet_len) { caplen = packet_len; } break; } if (caplen > p->snapshot) caplen = p->snapshot; /* Count lost packets. */ if (header->lctr) { if (p->md.stat.ps_drop > (UINT_MAX - header->lctr)) { p->md.stat.ps_drop = UINT_MAX; } else { p->md.stat.ps_drop += header->lctr; } } /* Run the packet filter if there is one. */ if ((p->fcode.bf_insns == NULL) || bpf_filter(p->fcode.bf_insns, dp, packet_len, caplen)) { /* convert between timestamp formats */ register unsigned long long ts; if (IS_BIGENDIAN()) { ts = SWAP_TS(header->ts); } else { ts = header->ts; } pcap_header.ts.tv_sec = ts >> 32; ts = (ts & 0xffffffffULL) * 1000000; ts += 0x80000000; /* rounding */ pcap_header.ts.tv_usec = ts >> 32; if (pcap_header.ts.tv_usec >= 1000000) { pcap_header.ts.tv_usec -= 1000000; pcap_header.ts.tv_sec++; } /* Fill in our own header data */ pcap_header.caplen = caplen; pcap_header.len = packet_len; /* Count the packet. */ p->md.stat.ps_recv++; /* Call the user supplied callback function */ callback(user, &pcap_header, dp); /* Only count packets that pass the filter, for consistency with standard Linux behaviour. */ processed++; if (processed == cnt) { /* Reached the user-specified limit. */ return cnt; } } } if (nonblocking || processed) { return processed; } } return processed; } /* * Get a handle for a live capture from the given DAG device. Passing a NULL * device will result in a failure. The promisc flag is ignored because DAG * cards are always promiscuous. The to_ms parameter is also ignored as it is * not supported in hardware. * * See also pcap(3). */ pcap_t *dag_open_live(const char *device, int snaplen, int promisc, int to_ms, char *ebuf) { char conf[30]; /* dag configure string */ pcap_t *handle; char *s; int n; if (device == NULL) { snprintf(ebuf, PCAP_ERRBUF_SIZE, "device is NULL: %s", pcap_strerror(errno)); return NULL; } /* Allocate a handle for this session. */ handle = malloc(sizeof(*handle)); if (handle == NULL) { snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc %s: %s", device, pcap_strerror(errno)); return NULL; } /* Initialize some components of the pcap structure. */ memset(handle, 0, sizeof(*handle)); if (strstr(device, "/dev") == NULL) { char * newDev = (char *)malloc(strlen(device) + 6); newDev[0] = '\0'; strcat(newDev, "/dev/"); strcat(newDev,device); device = newDev; } else { device = strdup(device); } if (device == NULL) { snprintf(ebuf, PCAP_ERRBUF_SIZE, "str_dup: %s\n", pcap_strerror(errno)); goto fail; } /* setup device parameters */ if((handle->fd = dag_open((char *)device)) < 0) { snprintf(ebuf, PCAP_ERRBUF_SIZE, "dag_open %s: %s", device, pcap_strerror(errno)); goto fail; } /* set the card snap length to the specified snaplen parameter */ if (snaplen == 0 || snaplen > MAX_DAG_SNAPLEN) { snaplen = MAX_DAG_SNAPLEN; } else if (snaplen < MIN_DAG_SNAPLEN) { snaplen = MIN_DAG_SNAPLEN; } /* snap len has to be a multiple of 4 */ snprintf(conf, 30, "varlen slen=%d", (snaplen + 3) & ~3); fprintf(stderr, "Configuring DAG with '%s'.\n", conf); if(dag_configure(handle->fd, conf) < 0) { snprintf(ebuf, PCAP_ERRBUF_SIZE,"dag_configure %s: %s\n", device, pcap_strerror(errno)); goto fail; } if((handle->md.dag_mem_base = dag_mmap(handle->fd)) == MAP_FAILED) { snprintf(ebuf, PCAP_ERRBUF_SIZE,"dag_mmap %s: %s\n", device, pcap_strerror(errno)); goto fail; } if(dag_start(handle->fd) < 0) { snprintf(ebuf, PCAP_ERRBUF_SIZE, "dag_start %s: %s\n", device, pcap_strerror(errno)); goto fail; } /* * Important! You have to ensure bottom is properly * initialized to zero on startup, it won't give you * a compiler warning if you make this mistake! */ handle->md.dag_mem_bottom = 0; handle->md.dag_mem_top = 0; /* TODO: query the card */ handle->md.dag_fcs_bits = 32; if ((s = getenv("ERF_FCS_BITS")) != NULL) { if ((n = atoi(s)) == 0 || n == 16|| n == 32) { handle->md.dag_fcs_bits = n; } else { snprintf(ebuf, PCAP_ERRBUF_SIZE, "pcap_open_live %s: bad ERF_FCS_BITS value (%d) in environment\n", device, n); goto fail; } } handle->snapshot = snaplen; /*handle->md.timeout = to_ms; */ if ((handle->linktype = dag_get_datalink(handle)) < 0) { snprintf(ebuf, PCAP_ERRBUF_SIZE, "dag_get_linktype %s: unknown linktype\n", device); goto fail; } handle->bufsize = 0; if (new_pcap_dag(handle) < 0) { snprintf(ebuf, PCAP_ERRBUF_SIZE, "new_pcap_dag %s: %s\n", device, pcap_strerror(errno)); goto fail; } /* * "select()" and "poll()" don't (yet) work on DAG device descriptors. */ handle->selectable_fd = -1; #ifdef linux handle->md.device = (char *)device; #else free((char *)device); device = NULL; #endif handle->read_op = dag_read; handle->setfilter_op = dag_setfilter; handle->set_datalink_op = dag_set_datalink; handle->getnonblock_op = pcap_getnonblock_fd; handle->setnonblock_op = dag_setnonblock; handle->stats_op = dag_stats; handle->close_op = dag_platform_close; return handle; fail: if (device != NULL) { free((char *)device); } if (handle != NULL) { free(handle); } return NULL; } static int dag_stats(pcap_t *p, struct pcap_stat *ps) { /* This needs to be filled out correctly. Hopefully a dagapi call will provide all necessary information. */ /*p->md.stat.ps_recv = 0;*/ /*p->md.stat.ps_drop = 0;*/ *ps = p->md.stat; return 0; } /* * Get from "/proc/dag" all interfaces listed there; if they're * already in the list of interfaces we have, that won't add another * instance, but if they're not, that'll add them. * * We don't bother getting any addresses for them. * * We also don't fail if we couldn't open "/proc/dag"; we just leave * the list of interfaces as is. */ int dag_platform_finddevs(pcap_if_t **devlistp, char *errbuf) { FILE *proc_dag_f; char linebuf[512]; int linenum; unsigned char *p; char name[512]; /* XXX - pick a size */ char *q; int ret = 0; /* Quick exit if /proc/dag not readable */ proc_dag_f = fopen("/proc/dag", "r"); if (proc_dag_f == NULL) { int i; char dev[16] = "dagx"; for (i = '0'; ret == 0 && i <= '9'; i++) { dev[3] = i; if (pcap_add_if(devlistp, dev, 0, NULL, errbuf) == -1) { /* * Failure. */ ret = -1; } } return (ret); } for (linenum = 1; fgets(linebuf, sizeof linebuf, proc_dag_f) != NULL; linenum++) { /* * Skip the first two lines - they're headers. */ if (linenum <= 2) continue; p = &linebuf[0]; if (*p == '\0' || *p == '\n' || *p != 'D') continue; /* not a Dag line */ /* * Get the interface name. */ q = &name[0]; while (*p != '\0' && *p != ':') { if (*p != ' ') *q++ = tolower(*p++); else p++; } *q = '\0'; /* * Add an entry for this interface, with no addresses. */ p[strlen(p) - 1] = '\0'; /* get rid of \n */ if (pcap_add_if(devlistp, name, 0, strdup(p + 2), errbuf) == -1) { /* * Failure. */ ret = -1; break; } } if (ret != -1) { /* * Well, we didn't fail for any other reason; did we * fail due to an error reading the file? */ if (ferror(proc_dag_f)) { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "Error reading /proc/dag: %s", pcap_strerror(errno)); ret = -1; } } (void)fclose(proc_dag_f); return (ret); } /* * Installs the given bpf filter program in the given pcap structure. There is * no attempt to store the filter in kernel memory as that is not supported * with DAG cards. */ static int dag_setfilter(pcap_t *p, struct bpf_program *fp) { if (!p) return -1; if (!fp) { strncpy(p->errbuf, "setfilter: No filter specified", sizeof(p->errbuf)); return -1; } /* Make our private copy of the filter */ if (install_bpf_program(p, fp) < 0) { snprintf(p->errbuf, sizeof(p->errbuf), "malloc: %s", pcap_strerror(errno)); return -1; } p->md.use_bpf = 0; return (0); } static int dag_set_datalink(pcap_t *p, int dlt) { return (0); } static int dag_setnonblock(pcap_t *p, int nonblock, char *errbuf) { /* * Set non-blocking mode on the FD. * XXX - is that necessary? If not, don't bother calling it, * and have a "dag_getnonblock()" function that looks at * "p->md.dag_offset_flags". */ if (pcap_setnonblock_fd(p, nonblock, errbuf) < 0) return (-1); if (nonblock) { p->md.dag_offset_flags |= DAGF_NONBLOCK; } else { p->md.dag_offset_flags &= ~DAGF_NONBLOCK; } return (0); } static int dag_get_datalink(pcap_t *p) { int linktype = -1; /* Check the type through a dagapi call. */ switch(dag_linktype(p->fd)) { case TYPE_HDLC_POS: { dag_record_t *record; /* peek at the first available record to see if it is PPP */ while ((p->md.dag_mem_top - p->md.dag_mem_bottom) < (dag_record_size + 4)) { p->md.dag_mem_top = dag_offset(p->fd, &(p->md.dag_mem_bottom), 0); } record = (dag_record_t *)(p->md.dag_mem_base + p->md.dag_mem_bottom); if ((ntohl(record->rec.pos.hdlc) & 0xffff0000) == 0xff030000) { linktype = DLT_PPP_SERIAL; fprintf(stderr, "Set DAG linktype to %d (DLT_PPP_SERIAL)\n", linktype); } else { linktype = DLT_CHDLC; fprintf(stderr, "Set DAG linktype to %d (DLT_CHDLC)\n", linktype); } break; } case TYPE_ETH: linktype = DLT_EN10MB; fprintf(stderr, "Set DAG linktype to %d (DLT_EN10MB)\n", linktype); break; case TYPE_ATM: linktype = DLT_ATM_RFC1483; fprintf(stderr, "Set DAG linktype to %d (DLT_ATM_RFC1483)\n", linktype); break; case TYPE_LEGACY: linktype = DLT_NULL; fprintf(stderr, "Set DAG linktype to %d (DLT_NULL)\n", linktype); break; default: fprintf(stderr, "Unknown DAG linktype %d\n", dag_linktype(p->fd)); break; } return linktype; }