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