pcap-enet.c revision 17683 
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 <sys/types.h>
11#include <sys/time.h>
12#include <sys/file.h>
13#include <sys/ioctl.h>
14#include <sys/socket.h>
15
16#include <net/if.h>
17#include <net/bpf.h>
18#include <net/enet.h>
19
20#include <netinet/in.h>
21#include <netinet/if_ether.h>
22
23#include <stdio.h>
24#include <errno.h>
25
26#include "interface.h"
27
28struct packet_header {
29#ifdef	IBMRTPC
30	struct LengthWords	length;
31	struct tap_header	tap;
32#endif	/* IBMRTPC */
33	u_char			packet[8]
34};
35
36extern int errno;
37
38#define BUFSPACE (4*1024)
39
40/* Forwards */
41static void efReadError(int, char *);
42
43void
44readloop(int cnt, int if_fd, struct bpf_program *fp, printfunc printit)
45{
46#ifdef	IBMRTPC
47	register struct packet_header *ph;
48	register u_char *bp;
49	register int inc;
50#else	/* !IBMRTPC */
51	static struct timeval tv = { 0 };
52#endif	/* IBMRTPC */
53	register int cc, caplen;
54	register struct bpf_insn *fcode = fp->bf_insns;
55	union {
56		struct packet_header hdr;
57		u_char	p[BUFSPACE];
58		u_short	s;
59	} buf;
60
61	while (1) {
62		if ((cc = read(if_fd, (char *)buf.p, sizeof(buf))) < 0)
63			efReadError(if_fd, "reader");
64
65#ifdef	IBMRTPC
66		/*
67		 * Loop through each packet.
68		 */
69		bp = buf.p;
70		while (cc > 0) {
71			ph = (struct packet_header *)bp;
72			caplen = ph->tap.th_wirelen > snaplen ? snaplen : ph->tap
73.th_wirelen ;
74			if (bpf_filter(fcode, (char *)ph->packet,
75						ph->tap.th_wirelen, caplen)) {
76				if (cnt >= 0 && --cnt < 0)
77					goto out;
78				(*printit)((char *)ph->packet,
79					(struct timeval *)ph->tap.th_timestamp,
80					ph->tap.th_wirelen, caplen);
81			}
82			inc = ph->length.PacketOffset;
83			cc -= inc;
84			bp += inc;
85		}
86#else	/* !IBMRTPC */
87		caplen = cc > snaplen ? snaplen : cc ;
88		if (bpf_filter(fcode, buf.hdr.packet, cc, caplen)) {
89			if (cnt >= 0 && --cnt < 0)
90				goto out;
91			(*printit)(buf.hdr.packet, &tv, cc, caplen);
92		}
93#endif	/* IBMRTPC */
94	}
95 out:
96	wrapup(if_fd);
97}
98
99/* Call ONLY if read() has returned an error on packet filter */
100static void
101efReadError(int fid, char *msg)
102{
103	if (errno == EINVAL) {	/* read MAXINT bytes already! */
104		if (lseek(fid, 0, 0) < 0) {
105			perror("tcpdump: efReadError/lseek");
106			exit(-1);
107		}
108		else
109			return;
110	}
111	else {
112		(void) fprintf(stderr, "tcpdump: ");
113		perror(msg);
114		exit(-1);
115	}
116}
117
118void
119wrapup(int fd)
120{
121#ifdef	IBMRTPC
122	struct enstats es;
123
124	if (ioctl(fd, EIOSTATS, &es) == -1) {
125		perror("tcpdump: enet ioctl EIOSTATS error");
126		exit(-1);
127	}
128
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",
137			es.enStat_MaxRead);
138	putc('\n', stderr);
139#endif	/* IBMRTPC */
140	close(fd);
141}
142
143int
144initdevice(char *device, int pflag, int *linktype)
145{
146	struct eniocb ctl;
147	struct enfilter filter;
148	u_int maxwaiting;
149	int if_fd;
150
151#ifdef	IBMRTPC
152	GETENETDEVICE(0, O_RDONLY, &if_fd);
153#else	/* !IBMRTPC */
154	if_fd = open("/dev/enet", O_RDONLY, 0);
155#endif	/* IBMRTPC */
156
157	if (if_fd == -1) {
158		perror("tcpdump: enet open error");
159		error(
160"your system may not be properly configured; see \"man enet(4)\"");
161		exit(-1);
162	}
163
164	/*  Get operating parameters. */
165
166	if (ioctl(if_fd, EIOCGETP, (char *)&ctl) == -1) {
167		perror("tcpdump: enet ioctl EIOCGETP error");
168		exit(-1);
169	}
170
171	/*  Set operating parameters. */
172
173#ifdef	IBMRTPC
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;
179#else	/* !IBMRTPC */
180	ctl.en_rtout = 64;	/* randomly picked value for HZ */
181#endif	/* IBMRTPC */
182	if (ioctl(if_fd, EIOCSETP, &ctl) == -1) {
183		perror("tcpdump: enet ioctl EIOCSETP error");
184		exit(-1);
185	}
186
187	/*  Flush the receive queue, since we've changed
188	    the operating parameters and we otherwise might
189	    receive data without headers. */
190
191	if (ioctl(if_fd, EIOCFLUSH) == -1) {
192		perror("tcpdump: enet ioctl EIOCFLUSH error");
193		exit(-1);
194	}
195
196	/*  Set the receive queue depth to its maximum. */
197
198	maxwaiting = ctl.en_maxwaiting;
199	if (ioctl(if_fd, EIOCSETW, &maxwaiting) == -1) {
200		perror("tcpdump: enet ioctl EIOCSETW error");
201		exit(-1);
202	}
203
204#ifdef	IBMRTPC
205	/*  Clear statistics. */
206
207	if (ioctl(if_fd, EIOCLRSTAT, 0) == -1) {
208		perror("tcpdump: enet ioctl EIOCLRSTAT error");
209		exit(-1);
210	}
211#endif	/* IBMRTPC */
212
213	/*  Set the filter (accept all packets). */
214
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");
219		exit(-1);
220	}
221	/*
222	 * "enetfilter" supports only ethernets.
223	 */
224	*linktype = DLT_EN10MB;
225
226	return(if_fd);
227}
228