/* * 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 */ #ifndef lint static const char rcsid[] = "@(#) $Header: /tcpdump/master/libpcap/pcap-dag.c,v 1.3 2003-07-25 04:04:57 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 struct mbuf; /* Squelch compiler warnings on some platforms for */ struct rtentry; /* declarations in */ #include #include #include #define MAX_DAG_SNAPLEN 2040 typedef struct pcap_dag_node { struct pcap_dag_node *next; pcap_t *p; } pcap_dag_node_t; static pcap_dag_node_t *pcap_dags = NULL; static int atexit_handler_installed = 0; #ifdef DAG_ONLY /* This code is reguired when compiling for a DAG device only. */ #include "pcap-dag.h" /* Replace dag function names with pcap equivalent. */ #define dag_stats pcap_stats #define dag_read pcap_read #define dag_open_live pcap_open_live #define dag_platform_finddevs pcap_platform_finddevs #define dag_setfilter pcap_setfilter #define dag_set_datalink_platform pcap_set_datalink_platform #endif /* DAG_ONLY */ static int dag_stats(pcap_t *p, struct pcap_stat *ps); 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); /* XXX - does "dag_close()" do this? If so, we don't need to. */ close(p->fd); } static void atexit_handler(void) { while (pcap_dags != NULL) { dag_platform_close(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; return 0; } /* * Get pointer to the ERF header for the next packet in the input * stream. This function blocks until a packet becomes available. */ static dag_record_t *get_next_dag_header(pcap_t *p) { register dag_record_t *record; int rlen; if (p->md.dag_mem_top - p->md.dag_mem_bottom < dag_record_size) { 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); rlen = ntohs(record->rlen); while (p->md.dag_mem_top - p->md.dag_mem_bottom < rlen) { 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); rlen = ntohs(record->rlen); } p->md.dag_mem_bottom += rlen; return record; } /* Size of payload in ATM packets */ #define ATM_CAPTURE_SIZE 48 /* Size of payload of Ethernet packet */ #define ETHERNET_LENGTH(h) min(ntohs((h)->wlen) - 4, ntohs((h)->rlen) - dag_record_size - 2 - (ntohs((h)->wlen) & 0x3)) /* Size of HDLC packet */ #define HDLC_LENGTH(h) min(ntohs((h)->wlen) - 4, ntohs((h)->rlen) - dag_record_size) #ifndef min #define min(a, b) ((a) > (b) ? (b) : (a)) #endif /* * Swap byte ordering of unsigned long long on a big endian * machine. */ static unsigned long long swapll(unsigned long long ull) { #if (BYTE_ORDER == BIG_ENDIAN) return ((ull & 0xff00000000000000LL) >> 56) | ((ull & 0x00ff000000000000LL) >> 40) | ((ull & 0x0000ff0000000000LL) >> 24) | ((ull & 0x000000ff00000000LL) >> 8) | ((ull & 0x00000000ff000000LL) << 8) | ((ull & 0x0000000000ff0000LL) << 24) | ((ull & 0x000000000000ff00LL) << 40) | ((ull & 0x00000000000000ffLL) << 56) ; #else return ull; #endif } /* * Read at most max_packets from the capture stream and call the callback * for each of them. Returns the number of packets handled or -1 if an * error occured. A blocking */ int dag_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user) { u_char *dp = NULL; int packet_len = 0, caplen = 0; struct pcap_pkthdr pcap_header; dag_record_t *header; register unsigned long long ts; /* Receive a single packet from the kernel */ header = get_next_dag_header(p); dp = ((u_char *)header) + dag_record_size; switch(header->type) { case TYPE_ATM: packet_len = ATM_CAPTURE_SIZE; caplen = ATM_CAPTURE_SIZE; break; case TYPE_ETH: packet_len = ntohs(header->wlen); caplen = ETHERNET_LENGTH(header); dp += 2; break; case TYPE_HDLC_POS: packet_len = ntohs(header->wlen); caplen = HDLC_LENGTH(header); break; } if (caplen > p->snapshot) caplen = p->snapshot; /* Run the packet filter if not using kernel filter */ if (p->fcode.bf_insns) { if (bpf_filter(p->fcode.bf_insns, dp, packet_len, caplen) == 0) { /* rejected by filter */ return 0; } } /* convert between timestamp formats */ ts = swapll(header->ts); pcap_header.ts.tv_sec = ts >> 32; ts = ((ts & 0xffffffffULL) * 1000 * 1000); ts += (ts & 0x80000000ULL) << 1; /* 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 += 1; } /* 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); return 1; } /* * 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; 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; } /* setup device parameters */ if((handle->fd = dag_open((char *)device)) < 0) { snprintf(ebuf, PCAP_ERRBUF_SIZE, "dag_open %s: %s", device, pcap_strerror(errno)); return NULL; } /* set the card snap length as specified by the specified snaplen parameter */ if (snaplen > MAX_DAG_SNAPLEN) { snaplen = MAX_DAG_SNAPLEN; } snprintf(conf, 30, "varlen slen=%d", (snaplen % 4) ? (snaplen + 3) & ~3 : snaplen); /* snap len has to be a multiple of 4 */ 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)); return NULL; } 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)); return NULL; } if(dag_start(handle->fd) < 0) { snprintf(ebuf, PCAP_ERRBUF_SIZE, "dag_start %s: %s\n", device, pcap_strerror(errno)); return NULL; } /* * 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; handle->md.is_dag = 1; handle->snapshot = snaplen; /*handle->md.timeout = to_ms; */ #ifdef linux if (device) { handle->md.device = strdup(device); } if (handle->md.device == NULL) { snprintf(ebuf, PCAP_ERRBUF_SIZE, "str_dup %s: %s\n", device, pcap_strerror(errno)); free(handle); return NULL; } #endif /* set link type */ /* Check the type through a dagapi call. */ switch(dag_linktype(handle->fd)) { case TYPE_HDLC_POS: handle->linktype = DLT_CHDLC; fprintf(stderr, "Set DAG linktype to %d (DLT_CHDLC)\n", handle->linktype); break; case TYPE_ETH: handle->linktype = DLT_EN10MB; fprintf(stderr, "Set DAG linktype to %d (DLT_EN10MB)\n", handle->linktype); break; case TYPE_ATM: handle->linktype = DLT_ATM_RFC1483; fprintf(stderr, "Set DAG linktype to %d (DLT_ATM_RFC1483)\n", handle->linktype); break; case TYPE_LEGACY: handle->linktype = DLT_NULL; fprintf(stderr, "Set DAG linktype to %d (DLT_NULL)\n", handle->linktype); break; default: snprintf(ebuf, PCAP_ERRBUF_SIZE, "dag_open_live %s: unknown linktype %d\n", device, dag_linktype(handle->fd)); return NULL; } handle->bufsize = 0;/*handle->snapshot;*/ if (new_pcap_dag(handle) < 0) { snprintf(ebuf, PCAP_ERRBUF_SIZE, "new_pcap_dag %s: %s\n", device, pcap_strerror(errno)); return NULL; } handle->stats_op = dag_stats; handle->close_op = dag_platform_close; return handle; } 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, *saveq; struct ifreq ifrflags; int ret = 0; /* Quick exit if /proc/dag not readable */ proc_dag_f = fopen("/proc/dag", "r"); if (proc_dag_f == NULL) { int i, fd; 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 gven 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. */ 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); } int dag_set_datalink_platform(pcap_t *p, int dlt) { return (0); }