1 /* $NetBSD: pcap-enet.c,v 1.2 2014/11/19 19:33:30 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 1.2 2014/11/19 19:33:30 christos Exp $"); 14 15 #ifdef HAVE_CONFIG_H 16 #include "config.h" 17 #endif 18 19 #include <sys/types.h> 20 #include <sys/time.h> 21 #include <sys/file.h> 22 #include <sys/ioctl.h> 23 #include <sys/socket.h> 24 25 #include <net/if.h> 26 #include <pcap/bpf.h> 27 #include <net/enet.h> 28 29 #include <netinet/in.h> 30 #include <netinet/if_ether.h> 31 32 #include <stdio.h> 33 #include <errno.h> 34 35 #include "interface.h" 36 37 struct packet_header { 38 #ifdef IBMRTPC 39 struct LengthWords length; 40 struct tap_header tap; 41 #endif /* IBMRTPC */ 42 u_char packet[8] 43 }; 44 45 extern int errno; 46 47 #define BUFSPACE (4*1024) 48 49 /* Forwards */ 50 static void efReadError(int, char *); 51 52 void 53 readloop(int cnt, int if_fd, struct bpf_program *fp, printfunc printit) 54 { 55 #ifdef IBMRTPC 56 register struct packet_header *ph; 57 register u_char *bp; 58 register int inc; 59 #else /* !IBMRTPC */ 60 static struct timeval tv = { 0 }; 61 #endif /* IBMRTPC */ 62 register int cc, caplen; 63 register struct bpf_insn *fcode = fp->bf_insns; 64 union { 65 struct packet_header hdr; 66 u_char p[BUFSPACE]; 67 u_short s; 68 } buf; 69 70 while (1) { 71 if ((cc = read(if_fd, (char *)buf.p, sizeof(buf))) < 0) 72 efReadError(if_fd, "reader"); 73 74 #ifdef IBMRTPC 75 /* 76 * Loop through each packet. 77 */ 78 bp = buf.p; 79 while (cc > 0) { 80 ph = (struct packet_header *)bp; 81 caplen = ph->tap.th_wirelen > snaplen ? snaplen : ph->tap 82 .th_wirelen ; 83 if (bpf_filter(fcode, (char *)ph->packet, 84 ph->tap.th_wirelen, caplen)) { 85 if (cnt >= 0 && --cnt < 0) 86 goto out; 87 (*printit)((char *)ph->packet, 88 (struct timeval *)ph->tap.th_timestamp, 89 ph->tap.th_wirelen, caplen); 90 } 91 inc = ph->length.PacketOffset; 92 cc -= inc; 93 bp += inc; 94 } 95 #else /* !IBMRTPC */ 96 caplen = cc > snaplen ? snaplen : cc ; 97 if (bpf_filter(fcode, buf.hdr.packet, cc, caplen)) { 98 if (cnt >= 0 && --cnt < 0) 99 goto out; 100 (*printit)(buf.hdr.packet, &tv, cc, caplen); 101 } 102 #endif /* IBMRTPC */ 103 } 104 out: 105 wrapup(if_fd); 106 } 107 108 /* Call ONLY if read() has returned an error on packet filter */ 109 static void 110 efReadError(int fid, char *msg) 111 { 112 if (errno == EINVAL) { /* read MAXINT bytes already! */ 113 if (lseek(fid, 0, 0) < 0) { 114 perror("tcpdump: efReadError/lseek"); 115 exit(-1); 116 } 117 else 118 return; 119 } 120 else { 121 (void) fprintf(stderr, "tcpdump: "); 122 perror(msg); 123 exit(-1); 124 } 125 } 126 127 void 128 wrapup(int fd) 129 { 130 #ifdef IBMRTPC 131 struct enstats es; 132 133 if (ioctl(fd, EIOSTATS, &es) == -1) { 134 perror("tcpdump: enet ioctl EIOSTATS error"); 135 exit(-1); 136 } 137 138 fprintf(stderr, "%d packets queued", es.enStat_Rcnt); 139 if (es.enStat_Rdrops > 0) 140 fprintf(stderr, ", %d dropped", es.enStat_Rdrops); 141 if (es.enStat_Reads > 0) 142 fprintf(stderr, ", %d tcpdump %s", es.enStat_Reads, 143 es.enStat_Reads > 1 ? "reads" : "read"); 144 if (es.enStat_MaxRead > 1) 145 fprintf(stderr, ", %d packets in largest read", 146 es.enStat_MaxRead); 147 putc('\n', stderr); 148 #endif /* IBMRTPC */ 149 close(fd); 150 } 151 152 int 153 initdevice(char *device, int pflag, int *linktype) 154 { 155 struct eniocb ctl; 156 struct enfilter filter; 157 u_int maxwaiting; 158 int if_fd; 159 160 #ifdef IBMRTPC 161 GETENETDEVICE(0, O_RDONLY, &if_fd); 162 #else /* !IBMRTPC */ 163 if_fd = open("/dev/enet", O_RDONLY, 0); 164 #endif /* IBMRTPC */ 165 166 if (if_fd == -1) { 167 perror("tcpdump: enet open error"); 168 error( 169 "your system may not be properly configured; see \"man enet(4)\""); 170 exit(-1); 171 } 172 173 /* Get operating parameters. */ 174 175 if (ioctl(if_fd, EIOCGETP, (char *)&ctl) == -1) { 176 perror("tcpdump: enet ioctl EIOCGETP error"); 177 exit(-1); 178 } 179 180 /* Set operating parameters. */ 181 182 #ifdef IBMRTPC 183 ctl.en_rtout = 1 * ctl.en_hz; 184 ctl.en_tr_etherhead = 1; 185 ctl.en_tap_network = 1; 186 ctl.en_multi_packet = 1; 187 ctl.en_maxlen = BUFSPACE; 188 #else /* !IBMRTPC */ 189 ctl.en_rtout = 64; /* randomly picked value for HZ */ 190 #endif /* IBMRTPC */ 191 if (ioctl(if_fd, EIOCSETP, &ctl) == -1) { 192 perror("tcpdump: enet ioctl EIOCSETP error"); 193 exit(-1); 194 } 195 196 /* Flush the receive queue, since we've changed 197 the operating parameters and we otherwise might 198 receive data without headers. */ 199 200 if (ioctl(if_fd, EIOCFLUSH) == -1) { 201 perror("tcpdump: enet ioctl EIOCFLUSH error"); 202 exit(-1); 203 } 204 205 /* Set the receive queue depth to its maximum. */ 206 207 maxwaiting = ctl.en_maxwaiting; 208 if (ioctl(if_fd, EIOCSETW, &maxwaiting) == -1) { 209 perror("tcpdump: enet ioctl EIOCSETW error"); 210 exit(-1); 211 } 212 213 #ifdef IBMRTPC 214 /* Clear statistics. */ 215 216 if (ioctl(if_fd, EIOCLRSTAT, 0) == -1) { 217 perror("tcpdump: enet ioctl EIOCLRSTAT error"); 218 exit(-1); 219 } 220 #endif /* IBMRTPC */ 221 222 /* Set the filter (accept all packets). */ 223 224 filter.enf_Priority = 3; 225 filter.enf_FilterLen = 0; 226 if (ioctl(if_fd, EIOCSETF, &filter) == -1) { 227 perror("tcpdump: enet ioctl EIOCSETF error"); 228 exit(-1); 229 } 230 /* 231 * "enetfilter" supports only ethernets. 232 */ 233 *linktype = DLT_EN10MB; 234 235 return(if_fd); 236 } 237