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