1 /* $NetBSD: pcap-enet.c,v 1.5 2024/09/02 15:33:37 christos Exp $ */ 2 3 /* 4 * Stanford Enetfilter subroutines for tcpdump 5 * 6 * Based on the MERIT NNstat etherifrt.c and the Ultrix pcap-pf.c 7 * subroutines. 8 * 9 * Rayan Zachariassen, CA*Net 10 */ 11 12 #include <sys/cdefs.h> 13 __RCSID("$NetBSD: pcap-enet.c,v 1.5 2024/09/02 15:33:37 christos Exp $"); 14 15 #include <config.h> 16 17 #include <sys/types.h> 18 #include <sys/time.h> 19 #include <sys/file.h> 20 #include <sys/ioctl.h> 21 #include <sys/socket.h> 22 23 #include <net/if.h> 24 #include <pcap/bpf.h> 25 #include <net/enet.h> 26 27 #include <netinet/in.h> 28 #include <netinet/if_ether.h> 29 30 #include <stdio.h> 31 #include <errno.h> 32 33 #include "interface.h" 34 35 struct packet_header { 36 #ifdef IBMRTPC 37 struct LengthWords length; 38 struct tap_header tap; 39 #endif /* IBMRTPC */ 40 u_char packet[8] 41 }; 42 43 extern int errno; 44 45 #define BUFSPACE (4*1024) 46 47 /* Forwards */ 48 static void efReadError(int, char *); 49 50 void 51 readloop(int cnt, int if_fd, struct bpf_program *fp, printfunc printit) 52 { 53 #ifdef IBMRTPC 54 register struct packet_header *ph; 55 register u_char *bp; 56 register int inc; 57 #else /* !IBMRTPC */ 58 static struct timeval tv = { 0 }; 59 #endif /* IBMRTPC */ 60 register int cc, caplen; 61 register struct bpf_insn *fcode = fp->bf_insns; 62 union { 63 struct packet_header hdr; 64 u_char p[BUFSPACE]; 65 u_short s; 66 } buf; 67 68 while (1) { 69 if ((cc = read(if_fd, (char *)buf.p, sizeof(buf))) < 0) 70 efReadError(if_fd, "reader"); 71 72 #ifdef IBMRTPC 73 /* 74 * Loop through each packet. 75 */ 76 bp = buf.p; 77 while (cc > 0) { 78 ph = (struct packet_header *)bp; 79 caplen = ph->tap.th_wirelen > snaplen ? snaplen : ph->tap 80 .th_wirelen ; 81 if (pcapint_filter(fcode, (char *)ph->packet, 82 ph->tap.th_wirelen, caplen)) { 83 if (cnt >= 0 && --cnt < 0) 84 goto out; 85 (*printit)((char *)ph->packet, 86 (struct timeval *)ph->tap.th_timestamp, 87 ph->tap.th_wirelen, caplen); 88 } 89 inc = ph->length.PacketOffset; 90 cc -= inc; 91 bp += inc; 92 } 93 #else /* !IBMRTPC */ 94 caplen = cc > snaplen ? snaplen : cc ; 95 if (pcapint_filter(fcode, buf.hdr.packet, cc, caplen)) { 96 if (cnt >= 0 && --cnt < 0) 97 goto out; 98 (*printit)(buf.hdr.packet, &tv, cc, caplen); 99 } 100 #endif /* IBMRTPC */ 101 } 102 out: 103 wrapup(if_fd); 104 } 105 106 /* Call ONLY if read() has returned an error on packet filter */ 107 static void 108 efReadError(int fid, char *msg) 109 { 110 if (errno == EINVAL) { /* read MAXINT bytes already! */ 111 if (lseek(fid, 0, 0) < 0) { 112 perror("tcpdump: efReadError/lseek"); 113 exit(-1); 114 } 115 else 116 return; 117 } 118 else { 119 (void) fprintf(stderr, "tcpdump: "); 120 perror(msg); 121 exit(-1); 122 } 123 } 124 125 void 126 wrapup(int fd) 127 { 128 #ifdef IBMRTPC 129 struct enstats es; 130 131 if (ioctl(fd, EIOSTATS, &es) == -1) { 132 perror("tcpdump: enet ioctl EIOSTATS error"); 133 exit(-1); 134 } 135 136 fprintf(stderr, "%d packets queued", es.enStat_Rcnt); 137 if (es.enStat_Rdrops > 0) 138 fprintf(stderr, ", %d dropped", es.enStat_Rdrops); 139 if (es.enStat_Reads > 0) 140 fprintf(stderr, ", %d tcpdump %s", es.enStat_Reads, 141 es.enStat_Reads > 1 ? "reads" : "read"); 142 if (es.enStat_MaxRead > 1) 143 fprintf(stderr, ", %d packets in largest read", 144 es.enStat_MaxRead); 145 putc('\n', stderr); 146 #endif /* IBMRTPC */ 147 close(fd); 148 } 149 150 int 151 initdevice(char *device, int pflag, int *linktype) 152 { 153 struct eniocb ctl; 154 struct enfilter filter; 155 u_int maxwaiting; 156 int if_fd; 157 158 #ifdef IBMRTPC 159 GETENETDEVICE(0, O_RDONLY, &if_fd); 160 #else /* !IBMRTPC */ 161 if_fd = open("/dev/enet", O_RDONLY, 0); 162 #endif /* IBMRTPC */ 163 164 if (if_fd == -1) { 165 perror("tcpdump: enet open error"); 166 error( 167 "your system may not be properly configured; see \"man enet(4)\""); 168 exit(-1); 169 } 170 171 /* Get operating parameters. */ 172 173 if (ioctl(if_fd, EIOCGETP, (char *)&ctl) == -1) { 174 perror("tcpdump: enet ioctl EIOCGETP error"); 175 exit(-1); 176 } 177 178 /* Set operating parameters. */ 179 180 #ifdef IBMRTPC 181 ctl.en_rtout = 1 * ctl.en_hz; 182 ctl.en_tr_etherhead = 1; 183 ctl.en_tap_network = 1; 184 ctl.en_multi_packet = 1; 185 ctl.en_maxlen = BUFSPACE; 186 #else /* !IBMRTPC */ 187 ctl.en_rtout = 64; /* randomly picked value for HZ */ 188 #endif /* IBMRTPC */ 189 if (ioctl(if_fd, EIOCSETP, &ctl) == -1) { 190 perror("tcpdump: enet ioctl EIOCSETP error"); 191 exit(-1); 192 } 193 194 /* Flush the receive queue, since we've changed 195 the operating parameters and we otherwise might 196 receive data without headers. */ 197 198 if (ioctl(if_fd, EIOCFLUSH) == -1) { 199 perror("tcpdump: enet ioctl EIOCFLUSH error"); 200 exit(-1); 201 } 202 203 /* Set the receive queue depth to its maximum. */ 204 205 maxwaiting = ctl.en_maxwaiting; 206 if (ioctl(if_fd, EIOCSETW, &maxwaiting) == -1) { 207 perror("tcpdump: enet ioctl EIOCSETW error"); 208 exit(-1); 209 } 210 211 #ifdef IBMRTPC 212 /* Clear statistics. */ 213 214 if (ioctl(if_fd, EIOCLRSTAT, 0) == -1) { 215 perror("tcpdump: enet ioctl EIOCLRSTAT error"); 216 exit(-1); 217 } 218 #endif /* IBMRTPC */ 219 220 /* Set the filter (accept all packets). */ 221 222 filter.enf_Priority = 3; 223 filter.enf_FilterLen = 0; 224 if (ioctl(if_fd, EIOCSETF, &filter) == -1) { 225 perror("tcpdump: enet ioctl EIOCSETF error"); 226 exit(-1); 227 } 228 /* 229 * "enetfilter" supports only ethernets. 230 */ 231 *linktype = DLT_EN10MB; 232 233 return(if_fd); 234 } 235