2 * Stanford Enetfilter subroutines for tcpdump
4 * Based on the MERIT NNstat etherifrt.c and the Ultrix pcap-pf.c
7 * Rayan Zachariassen, CA*Net
10 #include <sys/types.h>
13 #include <sys/ioctl.h>
14 #include <sys/socket.h>
20 #include <netinet/in.h>
21 #include <netinet/if_ether.h>
26 #include "interface.h"
28 struct packet_header {
30 struct LengthWords length;
31 struct tap_header tap;
38 #define BUFSPACE (4*1024)
41 static void efReadError(int, char *);
44 readloop(int cnt, int if_fd, struct bpf_program *fp, printfunc printit)
47 register struct packet_header *ph;
51 static struct timeval tv = { 0 };
53 register int cc, caplen;
54 register struct bpf_insn *fcode = fp->bf_insns;
56 struct packet_header hdr;
62 if ((cc = read(if_fd, (char *)buf.p, sizeof(buf))) < 0)
63 efReadError(if_fd, "reader");
67 * Loop through each packet.
71 ph = (struct packet_header *)bp;
72 caplen = ph->tap.th_wirelen > snaplen ? snaplen : ph->tap
74 if (bpf_filter(fcode, (char *)ph->packet,
75 ph->tap.th_wirelen, caplen)) {
76 if (cnt >= 0 && --cnt < 0)
78 (*printit)((char *)ph->packet,
79 (struct timeval *)ph->tap.th_timestamp,
80 ph->tap.th_wirelen, caplen);
82 inc = ph->length.PacketOffset;
87 caplen = cc > snaplen ? snaplen : cc ;
88 if (bpf_filter(fcode, buf.hdr.packet, cc, caplen)) {
89 if (cnt >= 0 && --cnt < 0)
91 (*printit)(buf.hdr.packet, &tv, cc, caplen);
99 /* Call ONLY if read() has returned an error on packet filter */
101 efReadError(int fid, char *msg)
103 if (errno == EINVAL) { /* read MAXINT bytes already! */
104 if (lseek(fid, 0, 0) < 0) {
105 perror("tcpdump: efReadError/lseek");
112 (void) fprintf(stderr, "tcpdump: ");
124 if (ioctl(fd, EIOSTATS, &es) == -1) {
125 perror("tcpdump: enet ioctl EIOSTATS error");
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",
144 initdevice(char *device, int pflag, int *linktype)
147 struct enfilter filter;
152 GETENETDEVICE(0, O_RDONLY, &if_fd);
154 if_fd = open("/dev/enet", O_RDONLY, 0);
158 perror("tcpdump: enet open error");
160 "your system may not be properly configured; see \"man enet(4)\"");
164 /* Get operating parameters. */
166 if (ioctl(if_fd, EIOCGETP, (char *)&ctl) == -1) {
167 perror("tcpdump: enet ioctl EIOCGETP error");
171 /* Set operating parameters. */
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;
180 ctl.en_rtout = 64; /* randomly picked value for HZ */
182 if (ioctl(if_fd, EIOCSETP, &ctl) == -1) {
183 perror("tcpdump: enet ioctl EIOCSETP error");
187 /* Flush the receive queue, since we've changed
188 the operating parameters and we otherwise might
189 receive data without headers. */
191 if (ioctl(if_fd, EIOCFLUSH) == -1) {
192 perror("tcpdump: enet ioctl EIOCFLUSH error");
196 /* Set the receive queue depth to its maximum. */
198 maxwaiting = ctl.en_maxwaiting;
199 if (ioctl(if_fd, EIOCSETW, &maxwaiting) == -1) {
200 perror("tcpdump: enet ioctl EIOCSETW error");
205 /* Clear statistics. */
207 if (ioctl(if_fd, EIOCLRSTAT, 0) == -1) {
208 perror("tcpdump: enet ioctl EIOCLRSTAT error");
213 /* Set the filter (accept all packets). */
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");
222 * "enetfilter" supports only ethernets.
224 *linktype = DLT_EN10MB;