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