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