1 /* 2 * Stanford Enetfilter subroutines for tcpdump 3 * 4 * Based on the MERIT NNstat etherifrt.c and the Ultrix pcap-pf.c 5 * subroutines. 6 * 7 * Rayan Zachariassen, CA*Net 8 */ 9 #ifndef lint 10 static const char rcsid[] _U_ = 11 "@(#) $Header: /tcpdump/master/libpcap/pcap-enet.c,v 1.9 2006-10-04 18:09:22 guy Exp $"; 12 #endif 13 14 #ifdef HAVE_CONFIG_H 15 #include "config.h" 16 #endif 17 18 #include <sys/types.h> 19 #include <sys/time.h> 20 #include <sys/file.h> 21 #include <sys/ioctl.h> 22 #include <sys/socket.h> 23 24 #include <net/if.h> 25 #include <pcap/bpf.h> 26 #include <net/enet.h> 27 28 #include <netinet/in.h> 29 #include <netinet/if_ether.h> 30 31 #include <stdio.h> 32 #include <errno.h> 33 34 #include "interface.h" 35 36 struct packet_header { 37 #ifdef IBMRTPC 38 struct LengthWords length; 39 struct tap_header tap; 40 #endif /* IBMRTPC */ 41 u_char packet[8] 42 }; 43 44 extern int errno; 45 46 #define BUFSPACE (4*1024) 47 48 /* Forwards */ 49 static void efReadError(int, char *); 50 51 void 52 readloop(int cnt, int if_fd, struct bpf_program *fp, printfunc printit) 53 { 54 #ifdef IBMRTPC 55 register struct packet_header *ph; 56 register u_char *bp; 57 register int inc; 58 #else /* !IBMRTPC */ 59 static struct timeval tv = { 0 }; 60 #endif /* IBMRTPC */ 61 register int cc, caplen; 62 register struct bpf_insn *fcode = fp->bf_insns; 63 union { 64 struct packet_header hdr; 65 u_char p[BUFSPACE]; 66 u_short s; 67 } buf; 68 69 while (1) { 70 if ((cc = read(if_fd, (char *)buf.p, sizeof(buf))) < 0) 71 efReadError(if_fd, "reader"); 72 73 #ifdef IBMRTPC 74 /* 75 * Loop through each packet. 76 */ 77 bp = buf.p; 78 while (cc > 0) { 79 ph = (struct packet_header *)bp; 80 caplen = ph->tap.th_wirelen > snaplen ? snaplen : ph->tap 81 .th_wirelen ; 82 if (bpf_filter(fcode, (char *)ph->packet, 83 ph->tap.th_wirelen, caplen)) { 84 if (cnt >= 0 && --cnt < 0) 85 goto out; 86 (*printit)((char *)ph->packet, 87 (struct timeval *)ph->tap.th_timestamp, 88 ph->tap.th_wirelen, caplen); 89 } 90 inc = ph->length.PacketOffset; 91 cc -= inc; 92 bp += inc; 93 } 94 #else /* !IBMRTPC */ 95 caplen = cc > snaplen ? snaplen : cc ; 96 if (bpf_filter(fcode, buf.hdr.packet, cc, caplen)) { 97 if (cnt >= 0 && --cnt < 0) 98 goto out; 99 (*printit)(buf.hdr.packet, &tv, cc, caplen); 100 } 101 #endif /* IBMRTPC */ 102 } 103 out: 104 wrapup(if_fd); 105 } 106 107 /* Call ONLY if read() has returned an error on packet filter */ 108 static void 109 efReadError(int fid, char *msg) 110 { 111 if (errno == EINVAL) { /* read MAXINT bytes already! */ 112 if (lseek(fid, 0, 0) < 0) { 113 perror("tcpdump: efReadError/lseek"); 114 exit(-1); 115 } 116 else 117 return; 118 } 119 else { 120 (void) fprintf(stderr, "tcpdump: "); 121 perror(msg); 122 exit(-1); 123 } 124 } 125 126 void 127 wrapup(int fd) 128 { 129 #ifdef IBMRTPC 130 struct enstats es; 131 132 if (ioctl(fd, EIOSTATS, &es) == -1) { 133 perror("tcpdump: enet ioctl EIOSTATS error"); 134 exit(-1); 135 } 136 137 fprintf(stderr, "%d packets queued", es.enStat_Rcnt); 138 if (es.enStat_Rdrops > 0) 139 fprintf(stderr, ", %d dropped", es.enStat_Rdrops); 140 if (es.enStat_Reads > 0) 141 fprintf(stderr, ", %d tcpdump %s", es.enStat_Reads, 142 es.enStat_Reads > 1 ? "reads" : "read"); 143 if (es.enStat_MaxRead > 1) 144 fprintf(stderr, ", %d packets in largest read", 145 es.enStat_MaxRead); 146 putc('\n', stderr); 147 #endif /* IBMRTPC */ 148 close(fd); 149 } 150 151 int 152 initdevice(char *device, int pflag, int *linktype) 153 { 154 struct eniocb ctl; 155 struct enfilter filter; 156 u_int maxwaiting; 157 int if_fd; 158 159 #ifdef IBMRTPC 160 GETENETDEVICE(0, O_RDONLY, &if_fd); 161 #else /* !IBMRTPC */ 162 if_fd = open("/dev/enet", O_RDONLY, 0); 163 #endif /* IBMRTPC */ 164 165 if (if_fd == -1) { 166 perror("tcpdump: enet open error"); 167 error( 168 "your system may not be properly configured; see \"man enet(4)\""); 169 exit(-1); 170 } 171 172 /* Get operating parameters. */ 173 174 if (ioctl(if_fd, EIOCGETP, (char *)&ctl) == -1) { 175 perror("tcpdump: enet ioctl EIOCGETP error"); 176 exit(-1); 177 } 178 179 /* Set operating parameters. */ 180 181 #ifdef IBMRTPC 182 ctl.en_rtout = 1 * ctl.en_hz; 183 ctl.en_tr_etherhead = 1; 184 ctl.en_tap_network = 1; 185 ctl.en_multi_packet = 1; 186 ctl.en_maxlen = BUFSPACE; 187 #else /* !IBMRTPC */ 188 ctl.en_rtout = 64; /* randomly picked value for HZ */ 189 #endif /* IBMRTPC */ 190 if (ioctl(if_fd, EIOCSETP, &ctl) == -1) { 191 perror("tcpdump: enet ioctl EIOCSETP error"); 192 exit(-1); 193 } 194 195 /* Flush the receive queue, since we've changed 196 the operating parameters and we otherwise might 197 receive data without headers. */ 198 199 if (ioctl(if_fd, EIOCFLUSH) == -1) { 200 perror("tcpdump: enet ioctl EIOCFLUSH error"); 201 exit(-1); 202 } 203 204 /* Set the receive queue depth to its maximum. */ 205 206 maxwaiting = ctl.en_maxwaiting; 207 if (ioctl(if_fd, EIOCSETW, &maxwaiting) == -1) { 208 perror("tcpdump: enet ioctl EIOCSETW error"); 209 exit(-1); 210 } 211 212 #ifdef IBMRTPC 213 /* Clear statistics. */ 214 215 if (ioctl(if_fd, EIOCLRSTAT, 0) == -1) { 216 perror("tcpdump: enet ioctl EIOCLRSTAT error"); 217 exit(-1); 218 } 219 #endif /* IBMRTPC */ 220 221 /* Set the filter (accept all packets). */ 222 223 filter.enf_Priority = 3; 224 filter.enf_FilterLen = 0; 225 if (ioctl(if_fd, EIOCSETF, &filter) == -1) { 226 perror("tcpdump: enet ioctl EIOCSETF error"); 227 exit(-1); 228 } 229 /* 230 * "enetfilter" supports only ethernets. 231 */ 232 *linktype = DLT_EN10MB; 233 234 return(if_fd); 235 } 236